n°02/2016 - Institut de Soudure

Transcription

ISDOC Publications
Veille scientifique et technique
n°02/2016
Auteur : Jérôme DIETSCH
Service Documentation
Date : 4 mars 2016
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Ce document est confidentiel et exclusivement destiné au personnel de
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Soudure. Il ne doit être ni reproduit, ni diffusé auprès d’autres établissements.
Votre contact : Frédéric Messager
Tél. : +33 (0)1 49 90 37 59
f.messager@isgroupe.com
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IS DO C P ub l ic at i o ns
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TABLE DES MATIERES
Soudage à l'électrode enrobée ........................................................................................... 6
Dans quels cas utiliser des électrodes enrobées à basse teneur en hydrogène
Phénomène de carburation lors de l'utilisation d'électrodes enrobées de base nickel de type ENiCrFe7
Soudage TIG ....................................................................................................................... 6
Mesure de la température d'un plasma d'arc TIG pulsé asymétrique à l'aide d'une méthode d'imagerie monochromatique
multidirectionnelle
Soudage plasma ................................................................................................................. 7
Variation dynamique et inclinaison de l'orifice débouchant du keyhole en soudage plasma
Système plasma à variation douce de polarité pour le soudage en corniche, et asymétrie des soudures obtenues
Soudage avec fil-électrode fusible ...................................................................................... 7
Analyse calorimétrique de l'ensemble des écoulements thermiques générés en soudage à l'arc avec fil-électrode fusible
Influence de la concentration en CO2 sur les performances opérationnelles du procédé de soudage avec fil-électrode fusible
en mode court-circuit
Influence des gaz de protection sur les performances des procédés de soudage et sur les caractéristiques des assemblages
soudés en acier duplex et superduplex
Possibilités de compensation d'un apport de chaleur élevé, notamment par le positionnement de la torche par rapport à la
tôle supérieure lors du soudage d'angle d'un assemblage à recouvrement
Optimisation des contraintes résiduelles en jouant sur les produits d'apport et l'apport de chaleur lors du soudage bout à
bout des aciers à haute résistance
Etude sur l'inertie thermique lors du soudage pulsé sous protection gazeuse avec fil-électrode fusible d'alliages d'aluminium
Contrôle du transfert de métal et de chaleur lors du soudage CMT d'assemblages acier/aluminium
Efficacité du procédé CMT pour le soudage des alliages d'aluminium 7075
Soudage sous protection gazeuse avec fil-électrode fusible des alliages de magnésium : films d'oxydes, surépaisseurs et
protubérances
Microstructure et caractéristiques mécaniques des assemblages à recouvrement aluminium/nickel réalisés par soudage CMT
Soudage par résistance .................................................................................................... 12
La productivité du procédé de soudage par résistance à la molette s'accroît grâce aux commandes adaptatives
Un traitement thermique après soudage innovant pour l'amélioration des caractéristiques mécaniques des assemblages
soudés par résistance par points
Profils de températures à l'interface des joints lors de la simulation du soudage par résistance par points d'aciers zingués et
d'aciers non-revêtus
Soudage par étincelage .................................................................................................... 13
Microstructure et tendance à la rupture des assemblages d'aciers dissemblables réalisés par soudage en bout par étincelage
Soudage par friction ......................................................................................................... 14
Simulation physique de l'évolution de la microstructure des assemblages soudés en alliage Ti-6Al-4V réalisés par friction
linéaire
Document confidentiel exclusivement destiné à l'Institut de Soudure et aux établissements Membres de l’Institut de Soudure ; toute reproduction ou redistribution interdite.
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Soudage par friction-malaxage ........................................................................................ 14
Etude paramétrique du procédé de soudage par friction-malaxage par points avec une tête de soudage sans pion appliqué à
l'alliage d'aluminium 5754
Amélioration des caractéristiques mécaniques d'assemblages de laitons 70/30 réalisés par friction-malaxage multipasse avec
refroidissement rapide
Clarification de l'écoulement de matière et de la formation de défauts en soudage par friction-malaxage
Caractérisation du procédé de soudage par friction-malaxage par points basée sur l'analyse de l'enveloppe de signaux vibroacoustiques
Soudage par friction-malaxage assisté par ultrasons de l'alliage d'aluminium 6061
Recours au soudage par friction-malaxage pour la réalisation d'assemblages dissemblables entre alliage d'aluminium (6111)
et thermoplastiques
Influence d'un traitement thermique après soudage sur la microstructure et les caractéristiques d'assemblages en acier
32Mn-7Cr-1Mo-0,3N réalisés par friction-malaxage
Stabilité des précipités de type Y-Ti-O dans les assemblages en alliages ferritiques nanostructurés réalisés par frictionmalaxage
Développement d'un équipement de soudage par friction-malaxage de petites dimensions actionné manuellement
Examen de la microstructure et caractéristiques mécaniques d'assemblages constitués de nuances dissemblables d'alliage de
magnésium réalisés par friction-malaxage
Soudage par friction-malaxage d'assemblages dissemblables aluminium/magnésium : influence de la position relative des
pièces
Complétion du trou laissé lors de la mise en œuvre du procédé de soudage par friction-malaxage à l'aide d'un outil disposant
d'un pion consommable
Amélioration de la macrosection, de la microstructure et des caractéristiques mécaniques des assemblages bout à bout en
alliage d'aluminium 2024-T4 réalisés au moyen du procédé de soudage par friction-malaxage amélioré par ultrasons
Soudage hybride .............................................................................................................. 19
Etude sur les mécanismes d'un procédé de soudage hybride TIG-MIG
Soudage laser ................................................................................................................... 20
Projections générées lors du soudage laser avec oscillation du faisceau
Influence de la composition chimique sur la microstructure et les caractéristiques mécaniques du métal fondu lors du
soudage laser d'un acier à haute résistance
Souder l'aluminium en combinant un laser à diode et un laser Nd:YAG pulsé
Soudage laser en mode keyhole de plusieurs épaisseurs de tôles fines en acier inoxydable pour la fabrication de piles à
combustible
Atténuation des défauts formés à la racine des joints en soudage laser et soudage hybride laser-arc
Soudage sous eau ............................................................................................................ 21
Etude préliminaire sur le soudage pleine eau avec chauffage par induction en temps réel
Soudage par explosion ..................................................................................................... 22
Mécanismes de formation de joints de haute qualité en acier inoxydable martensitiques assemblés par diffusion
Produits d'apport ............................................................................................................. 22
Caractéristiques et soudabilité de nuances modifiées de fils d'apport à basse température de transformation de phase
Evaluation de nouveaux produits d'apport sans argent pour le brasage
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Procédés de soudage spéciaux ......................................................................................... 23
Modélisation des cycles thermiques et du grossissement des composés intermétalliques lors de l'assemblage au moyen du
procédé FMB (Friction Melt Bonding) d'un acier à ultra-faible teneur en carbone à l'alliage d'aluminium 2024-T3
Le soudage par décharge de condensateurs gagne en attractivité
Assemblage par diffusion ................................................................................................. 24
Mécanisme d'interaction entre les interstices et l'interface des joints de grains en assemblage par diffusion
Brasage fort ..................................................................................................................... 24
Microstructures des assemblages TiAl brasés avec produits d'apport de base Ti-Zr
Comportement des couches d'oxydes sur aluminium lors de traitements thermiques et leur influence sur la brasabilité
Influence de la couche intermédiaire de zinc sur la brasabilité de l'alliage de magnésium AZ31B sur tôles fines d'acier
Un procédé de brasage pour la fabrication rapide de panneaux laminés constitués de tôles fines
Microstructure à l'interface d'assemblages dissemblables alliage de magnésium AZ1B / acier étamé brasés au laser
Brasage tendre ................................................................................................................. 26
Caractérisation et cinétique de formation de composés intermétalliques à l'état liquide lors du brasage tendre avec produits
d'apport sans plomb
Soudobrasage................................................................................................................... 27
Effet de l'aluminisation par immersion à chaud sur les caractéristiques mécaniques et la microstructure à l'interface des
assemblages Ti/Al réalisés par soudobrasage TIG
Rechargement .................................................................................................................. 27
Contrôle de la variable électrode positive/électrode négative lors du rechargement dur sous flux en polarité variable de
carbures de chrome primaires
Traitements thermiques ................................................................................................... 28
Le préchauffage - Mal compris, souvent négligé et parfois mal effectué
Effets d'un TTAS sur la microstructure et les caractéristiques mécaniques d'un métal fondu ERNiCrFe-7 hors dilution
Traitement thermique après soudage de fontes de fortes épaisseurs
Coupage ........................................................................................................................... 29
Sélectionner un équipement de coupage plasma
Ventilation des tables automatisées pour la découpe des métaux
Collage ............................................................................................................................. 29
Influence du processus de durcissement sur la résistance d'assemblages collés à l'aide d'adhésifs durcissant à chaud
Mécanismes de frittage et caractéristiques mécaniques d'assemblages collés réalisés à l'aide de nanoparticules d'argent et
destinés à des applications électroniques
Plastiques......................................................................................................................... 30
Etude sur le soudage par vibration linéaire du nylon type 66 renforcé de fibre de verre - Lauréat du prix Henry Granjon 2014
catégorie A : technologies d'assemblage et de fabrication
Dégradation thermique du polycarbonate et du polyamide 6 en soudage laser par transmission
Matériaux dissemblables .................................................................................................. 31
Etude expérimentale et modélisation de couches fondues dans des structures mixtes polymère/métal
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Caractéristiques méaniques d'assemblages dissemblables constitués d'acier DP 980 et d'alliage d'aluminium 7075-T6
Effet d'un traitement électrolytique au plasma pour l'assemblage des métaux aux plastiques
Métallurgie du soudage .................................................................................................... 32
Evolution de l'hydrogène dans la ZAT d'un acier à précipitation de cuivre de grade 780 MPa au regard de sa susceptibilité à la
fissuration à froid
Formation de zone appauvries en manganèse dans les zones fondues contenant du titane
Observation in situ de la formation de ferrite aciculaire et de l'affinage des grains dans la zone affectée thermiquement
simulée d'un acier à haute résistance faiblement allié
Mode de solidification du métal fondu d'un alliage de base nickel à forte teneur en chrome
Effet des variantes de transformations cristallographiques en zone fondue de soudures réalisées sous protection gazeuse
avec fil-électrode fusible
Influence de l'azote sur la microstructure et les caractéristiques mécaniques des alliages de nickel
Fatigue ............................................................................................................................. 34
Assurance qualité du traitement de martelage à haute fréquence des soudures à l'aide d'un système de balayage laser 3D
manuel
Une nouvelle méthode pour les essais de fatigue-corrosion appliqués au placage des tubes d'eau
Fluage .............................................................................................................................. 35
Corrélation entre formation de ferrite et tenue au fluage des soudures sur acier Cr-Mo - Lauréat du prix Henry Granjon 2013
catégorie B : comportement des matériaux et soudabilité
Contraintes, déformations et retrait ................................................................................. 36
Effets de la transformation de la phase austénitique sur les contraintes résiduelles de soudures longitudinales ne supportant
pas de charges
Analyse numérique de l'effet des hétérogénéités de résistance mécanique sur le champ de contraintes d'éprouvettes Charpy
Mesure in situ et modélisation des déformations et de la température lors du soudage à l'arc
Profil des contraintes résiduelles dans les assemblages de tôles fines d'acier réalisés par rivetage
Influences des caractéristiques mécaniques du métal fondu et de la température de transformation de phase sur les
contraintes résiduelles de soudage
Conception et calcul ......................................................................................................... 37
Optimisation de viroles tronconiques soudées soumises à compression axiale et charges de flexion
Longueur efficace des soudures pour les assemblages en T de sections creuses rectangulaires soumis à des charges de flexion
- Lauréat du prix Henry Granjon 2014 catégorie C : conception et intégrité structurale
Contrôles non destructifs ................................................................................................. 38
Une méthode à ondelette innovante pour la surveillance par vibration de roulements à bille
Une méthode CND micro-magnétique pour l'évaluation des délaminages dans les plastiques renforcés de fibres de carbone
Analyses théoriques d'une méthode de contrôle par flux de fuite d'un courant électrique alternatif et vérification
expérimentale
Identification de défauts internes et externes sur pipelines à l'aide de la méthode PSO-SVM
Détection de défauts typiques dans les câbles en acier au moyen d'une analyse en ondelettes
Avancées en matière de probabilité de détection au travers d'études de modélisation et de simulation
Quantile de probabilité de détection : distinction entre incertitude et variabilité en contrôle non-destructif
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Vraisemblance des indications : que faire lorsque la probabilité de détection demeure incertaine
Les défis posés par la fiabilité des contrôles non-destructifs
Conception d'un système perfectionné d'inspection automatisé pour composants aéronautiques basé sur le ressuage
fluorescent
Utilisation de la décomposition modale empirique et d'un algorithme flou pour l'analyse de radiographies de soudures
Système mobile de radiographie X à haute énergie pour le contrôle non destructif des conteneurs de frêt
Industrie automobile ........................................................................................................ 43
Améliorer la formabilité d'assemblages en aciers dual phase destinés à l'industrie automobile réalisés par faisceau laser avec
refroidissement localisé
Industrie aéronautique et aérospatiale ............................................................................ 43
Réaliser un commutateur parfaitement étanche pour l'aéronautique
Industrie électronique ...................................................................................................... 44
Soudage des batteries : un guide pour le choix et la mise en œuvre des procédés d'assemblage
LISTE DES PUBLICATIONS ANALYSEES ............................................................................ 45
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Soudage à l'électrode enrobée
Dans quels cas utiliser des électrodes enrobées à basse teneur en hydrogène
The case for using low-hydrogen covered electrodes
With its versatility, ease of use, and capability to reduce harmful hydrogen diffusion in the weld deposit, the low-hydrogen
covered electrode is a wise choice. While mechanized welding is seen as the future for a number of applications, shielded
metal arc welding (SMAW) in combination with low-hydrogen electrodes often can prove to be the best choice. Lowhydrogen electrodes are the logical choice for a variety of welding applications. Following is a look at what low-hydrogen
electrodes are and why they work so well.
Auteur(s) : BYALL L.
Affiliation(s) : The Lincoln Electric Co., Cleveland
Pays : Etats-Unis
Source : Welding Journal, vol.94, n°1, 2015, pp. 28-30 (3 pages) , en anglais
Cote ISDOC : WJ201501.28-30
Phénomène de carburation lors de l'utilisation d'électrodes enrobées de base nickel de type
ENiCrFe7
Carburization phenomenon of ENiCrFe7 nickel-based alloy covered electrode
The ENiCrFe7 nickel-based alloy covered electrode is a key welding material for the construction of nuclear power plants. But
this material is very susceptible to ductility dip cracking (DDC) at elevated temperatures. The carbon level in the weld has
evidently shown its significance for the DDC susceptibility. However, it is practically difficult to decrease the carbon content
in the deposited metal of this welding material. To clarify such carburization phenomenon, a systematic experiment was
performed to investigate the controlling factors. It was found that the carburization was a universal phenomenon that
occurred in the three different slag systems. The acidic (CaO-TiO2-SiO2 type) and neutral (CaO-CaF2-TiO2 type) slag systems
exhibited relatively lower carburization; but the basic (CaO-CaF2 type) slag demonstrated the largest carburization. It was
confirmed that the carbon source was from the carbonates in the flux coating, which decomposed out carbon step by step
and directly contributed to the carburization. The ferrosilicon and ferrotitanium could deoxidize the carbon from the carbon
oxide at the welding temperature, thus indirectly contributing to the carburization. The larger welding current resulted in
larger heat input and higher welding temperature that facilitated the decomposition of carbon oxide, therefore leading to
the larger carburization.
Auteur(s) : QIN R., HE G.
Affiliation(s) : State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University
Pays : Chine
Source : Welding Journal, vol.94, n°3, 2015, pp. 83s-90s (8 pages) , en anglais
Cote ISDOC : WJ201503.83s-90s
Soudage TIG
Mesure de la température d'un plasma d'arc TIG pulsé asymétrique à l'aide d'une méthode
d'imagerie monochromatique multidirectionnelle
Temperature measurement of asymmetrical pulsed TIG arc plasma by multidirectional monochromatic imaging method
Arc plasma diagnostics by spectroscopy have been often used to measure the arc properties, such as the temperature.
Measurements of an axially asymmetrical arc plasma require the optical computed tomography technique. This study
constructed the simultaneous and multidirectional measurement system by six sets of CCD camera and interference filter
with monochromatic imaging method. The deviation of the central wavelength of the filters was calibrated by tilting
operation, and the sensitivity of detectors was calibrated by referencing the stationary and axially symmetric tungsten inert
gas (TIG) arc plasma. We could perform the temperature measurement of the transient and asymmetrical TIG arc plasma
such as in the transition period between the peak 150 A and base 10 A current of a 50 Hz pulsed TIG arc with 30° tilted torch.
It was revealed that the high-temperature area of 30° tilted arc is larger than that of perpendicular arc. The comparison of
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pulsed and continuous arcs shows that the arc shape and the temperature variation reasonably followed the current change
as long as the changing rate was about -113 A/ms.
Auteur(s) : NOMURA K., KISHI T., SHIRAI K., HIRATA Y., KATAOKA K.
Affiliation(s) : Osaka University
Pays : Japon
Source : Welding in the World, vol.59, n°2, mars 2015, pp. 283-293 (11 pages) , en anglais
Cote ISDOC : WW201502.283-293
Soudage plasma
Variation dynamique et inclinaison de l'orifice débouchant du keyhole en soudage plasma
Dynamic variation of keyhole exit and its inclination in plasma arc welding
The dynamic behavior of keyhole in plasma arc welding determines the weld quality. In this study, the keyhole images are
observed during the process, and both the keyhole geometry and its position relative to the torch axis are determined. The
deviation distance of the keyhole exit at bottom side of the workpiece from the torch centerline is used to describe the
extent of keyhole inclination and is measured based on the captured sequential images of the keyhole exit. Experiments are
conducted to study the dynamic variation of keyhole exit and its inclination extent. The interaction between the plasma arc
and the molten pool and its influence on the keyhole inclination are analyzed. The results lay solid foundation for monitoring
and controlling the thermal process in keyhole plasma arc welding.
Auteur(s) : WU C.S., LIU Z.M.
Affiliation(s) : Shandong University, Tianjin University
Pays : Chine
Source : Welding in the World, vol.59, n°3, mai 2015, pp. 365-371 (7 pages) , en anglais
Cote ISDOC : WW201503.365-371
Système plasma à variation douce de polarité pour le soudage en corniche, et asymétrie des
soudures obtenues
Soft variable polarity plasma arc horizontal welding technology and weld asymmetry
Soft variable polarity plasma arc welding technology has been proposed to solve the problems in horizontal position welding
for aluminium alloys. Arc thermal field shape, arc pressure distribution and the characteristic of the weld pool, which are
important for keyhole stability, have been changed compared with the ordinary variable polarity plasma arc. Its stability in
application can be evaluated by the operational window. The thermal cycle curves, microstructures and micro-hardness of
the horizontal position weld indicate the weld asymmetry. The influence of asymmetry as well as welding defects on tensile
strength and fracture behaviour has been studied. The fundamental reason for the asymmetry was considered as the
asymmetric fluid flow around the keyhole in the weld pool.
Auteur(s) : ZHANG Q.L., YANG C.L., LIN S.B., FAN C.L.
Affiliation(s) : State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology
Pays : Chine
Source : Science and Technology of Welding and Joining, vol.20, n°4, 2015, pp. 297-306 (10 pages) , en anglais
Cote ISDOC : STWJ201504.297-306
Soudage avec fil-électrode fusible
Analyse calorimétrique de l'ensemble des écoulements thermiques générés en soudage à l'arc
avec fil-électrode fusible
Calorimetric analyses of the comprehensive heat flow for gas metal arc welding
Within this manuscript, the comprehensive heat flow, as well as the energy balance for gas-shielded arc welding processes
based on experimental investigations is discussed. The main focus lies on the gas metal arc welding (GMAW) process which is
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further analysed. Different calorimetric measurement methods and results for the separate determination of the energy
content of droplet and welding arc as well as energy input into the component are presented. Additionally, heat losses to the
surrounding atmosphere and the cooling energy of the external cooling power source system are analysed. The mean droplet
temperatures are within a range of Tdr=2350-2700 °C. The studies also show that a specific manipulation of the droplet
temperature during the welding process is not possible and droplet temperature depends on several parameters. Increasing
the wire feed speed, reducing the diameter of the filler material or increasing the stick out length result in an increase of the
droplet temperature. The analyses allow to conclude that the welding arc is mainly responsible for the weld seam
penetration and the droplet temperature only contributes in a minor manner. Preliminary experiments also show that the
heat input into the component is highly influenced by the selection of welding parameters. Measurements confirm that it is
possible to increase the efficiency of welding processes for example by reducing the wire feed speed, using carbon dioxide
shielding gas or increasing the stick out length. On the contrary, increasing the current or voltage or reducing the shielding
gas flow reduces the process efficiency. The difference between the lowest and highest achievable value of efficiency can be
more than 15 % for one specific welding process.
Auteur(s) : HAELSIG A., KUSCH M., MAYR P.
Affiliation(s) : Technische Universität Chemnitz
Pays : Allemagne
Cote ISDOC : WW201502.191-199
Influence de la concentration en CO2 sur les performances opérationnelles du procédé de soudage
avec fil-électrode fusible en mode court-circuit
Influence of the CO2 content on operational performance of short-circuit GMAW
CO2 blended with Ar is the most common shielding gas used for short-circuit gas metal arc welding (GMAW). There has been
some technical knowledge devised from the process application over the years (personal opinion and results from practice)
on the selection of the gas blend composition. However, there is still a lack of more scientific data to explain the performance
of the mixtures. This paper presents a systematic study of the influence that CO 2 content in mixture with Argon has on the
operational performance of the short circuit GMAW. The objectives of this study were to describe, to quantify and to explain
the alterations in the metal transfer behavior, spatter generation, weld bead geometry and bead finish due to the different
CO2 contents in the shielding gas. Carbon steel plates were welded in adequate parametric conditions for each CO 2 + Ar
shielding gas composition (CO2 ranging from 2 to 100 %). These parametric conditions were found by applying a metal
transfer regularity index over welds carried out at different voltage settings for each gas blend. A target of 130 A was applied
as base for comparison. Laser shadowgraphy with high-speed filming and current and voltage oscillograms were used as
analysis tools. The results showed (and confirmed) that the increase of the CO 2 content deteriorates metal transfer
regularity, leading to excessive spatter generation and uneven bead appearance, but increases the penetration and the
fusion area of the weld beads and improves bead convexity. In general, the CO 2 content should neither be lower than 10 %
(unless for thin plates) nor higher than 30 %.
Auteur(s) : LISKEVYCH O., SCOTTI A.
Affiliation(s) : Center for Research and Development of Welding Processes, Federal University of Uberlandia (Laprosolda
Pays : Brésil
Cote ISDOC : WW201502.217-224
Influence des gaz de protection sur les performances des procédés de soudage et sur les
caractéristiques des assemblages soudés en acier duplex et superduplex
Effect of shielding gas on welding performance and properties of duplex and superduplex stainless steel welds
The influence of shielding gases on welding performance and on properties of duplex and super duplex stainless steel welds
was studied. Using argon as the reference gas, helium, nitrogen and carbon dioxide were added and five mixtures evaluated.
Bead-on-plate welds and circumferential pipe welds were produced using mechanized GMA welding in the down hand
position. Welding performance, corrosion resistance, mechanical properties, microstructural features and weld imperfections
were assessed and related to the shielding gas. Shielding gases containing 30 % helium showed excellent results; whilst pure
argon showed unstable arc and poor weld pool fluidity and Ar + 2% CO2 resulted in under fill and porosity. Mixtures
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containing helium resulted in higher ductility welds and higher impact toughness values than welds produced with Ar + 2%
CO2. Sound and balanced duplex microstructures free from inter metallics were found with suitable ferrite contents for all
the shielding gases studied. All the duplex pipe welds passed the corrosion test regardless of the shielding gas used, and the
best results in the corrosion test for super duplex pipe welds were found when using Ar + 30% He + 0.5% CO2 + 1.8 % N2 as
shielding gas.
Auteur(s) : VALIENTE BERMEJO M.A., KARLSSON L., SVENSSON L.E., HURTIG K., RASMUSON H., FRODIGH M., BENGTSSON P.
Affiliation(s) : Department of Engineering Science, University West, ESAB AB, Sandvik Materials Technology, AGA Gas AB
Pays : Suède
Cote ISDOC : WW201502.239-249
Possibilités de compensation d'un apport de chaleur élevé, notamment par le positionnement de
la torche par rapport à la tôle supérieure lors du soudage d'angle d'un assemblage à recouvrement
Possibilities for compensating a higher heat input, in particular by the torch offset relative to the top sheet at the fillet
weld on a lap joint
This paper deals with the use of an adaptive control system for compensating the variation in the gap height of a fillet welded
lap joint. Gap bridging requires the input of additional filler material and is related to an increased energy input. Hence, the
aim was a compensation of the effect of an increased heat input, in order to maintain the weld pool and excessive
penetration, which can prevent consequently root reinforcement and burn-through. The findings achieved in this work show
possibilities for a real-time controlled adjustments of the welding parameters in automated metal active gas (MAG) welding
for compensating a higher heat input, in particular by means of the torch offset relative to the top sheet at the fillet weld on
a lap joint.
Auteur(s) : EBERT-SPIEGEL M., GOECKE S.F., RETHMEIER M.
Affiliation(s) : Brandenburg University of Applied Science, BAM Federal Institute for Materials Research and Testing
Pays : Allemagne
Cote ISDOC : WW201503.443-453
Optimisation des contraintes résiduelles en jouant sur les produits d'apport et l'apport de chaleur
lors du soudage bout à bout des aciers à haute résistance
Improving welding stresses by filler metal and heat control selection in component-related butt joints of high-strength
steel
The application of high-strength fine-grained structural steels with yield strengths greater than or equal to 690 MPa expands
because of present light weight design trends. The requirements regarding the welded components safety increased due to
high loading capacity. This determines a sustainable and economic application as well. However, high welding residual
stresses could diminish the components safety, especially due to high restraint conditions in component or repair welds.
Therefore, this work is concerned with global and local welding stresses, especially crack-critical welding stresses in the HAZ
and while root welding due to the restraint conditions. Restraint intensities of real components were analysed and realised
with two different weld tests, alongside two different plate dimensions and steel grades. A comparison of the test results
showed several significant effects for heat control and restraint intensity regarding restraint forces and local welding
stresses. Among these effects, substantial influences were found for the filler metal selection with partially altered results for
root and filler beads. Local stresses of weld seam and HAZ were affected differently.
Auteur(s) : SCHROEPFER D., KROMM A., KANNENGIESSER T.
Affiliation(s) : BAM Federal Institute for Materials Research and Testing
Pays : Allemagne
Cote ISDOC : WW201503.455-464
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Etude sur l'inertie thermique lors du soudage pulsé sous protection gazeuse avec fil-électrode
fusible d'alliages d'aluminium
Investigation on thermal inertia of GMAW-P welding on Al alloy
Thermal inertia relates to the rate at which the plasma cools and heats, which plays important role in improving the arc
stability at base time of pulsed gas metal arc welding (GMAW-P). A three dimensional (3D) transient model is established to
investigate the thermal inertia due to current rapid variation of GMAW-P. The model is validated by comparison of measured
and predicted arc profile and voltage. Thermal inertia increases as the current decent rate improves at the same current
difference. Two high thermal inertia zones exist in arc region, one locates right under the wire tip, and another is above
molten pool surface. The arc region with high temperature is broadened due to thermal inertia compared to constant
current, which is more obvious as the current decent rate increases. The results show that thermal inertia remarkably
-1
influences the arc temperature and stability while current decent rate is higher than 130 A ms .
Auteur(s) : WANG L.L., LU F.G., CUI H.C., TANG X.H.
Affiliation(s) : School of Materials Science and Engineering, Shanghai Jiao Tong University
Pays : Chine
Contrôle du transfert de métal et de chaleur lors du soudage CMT d'assemblages acier/aluminium
Control of mass and heat transfer for steel/aluminium joining using cold metal transfer process
The Cold Metal Transfer process is investigated to join zinc coated steel with aluminium alloy by braze-welding. A 4043 filler
metal is deposited on the surface of the coated steel, and the effect of the current waveform on the metal transfer and the
heat transferred to the base metal is investigated. The reduction in the ‘boost phase’ duration of the current waveform
decreases the volume of liquid drops at the wire tip and allows to increase the short-circuit frequency, inducing a similar or
-1
higher deposit rate. Regular deposits are obtained when the linear energy remains below, approx. 500 J mm . The heat
transferred to the base metal, and thus the thickness of the intermetallic layer formed at the Al/steel interface, is lower for
an equivalent deposit rate when the short-circuit frequency is high.
Auteur(s) : MEZRAG B., DESCHAUX-BEAUME F., BENACHOUR M.
Affiliation(s) : Mechanical and Civil Engineering Laboratory, University Montpellier II, Ingeniery of Mechanical Systems and Materials Laboratory,
University of Tlemcem
Pays : Algérie
Efficacité du procédé CMT pour le soudage des alliages d'aluminium 7075
Effectiveness of cold metal transfer process for welding 7075 aluminium alloys
Cold metal transfer (CMT) welding is a promising process to improve the mechanical characteristics of the hard to weld 7075T6 aluminium alloy owing to its unique advantages in contrast to conventional metal inert gas welding process. The welded
joints, using ER5356, were identified and characterised by means of optical microscopy, scanning electron microscopy and
energy dispersive spectroscopy. Mechanical properties were measured by tensile and hardness tests. Results indicate that
CMT provides better joint tensile strength and ductility compared to metal inert gas welding. The softness in the heat
affected zone was very low, but a big hardness gap was recognised in the welded metal compared to base metal. The joint
had mechanical property coefficients of 77%, 60% and 69% for yield strength, ultimate tensile strength and elongation
respectively.
Auteur(s) : ELREFAEY A.
Affiliation(s) : Austrian Institute of Technology
Pays : Autriche
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Soudage sous protection gazeuse avec fil-électrode fusible des alliages de magnésium : films
d'oxydes, surépaisseurs et protubérances
L'utilisation du magnésium pour l'allègement des véhicules tend à se généraliser. Le soudage sous protection gazeuse avec
fil-électrode fusible peut tout à fait convenir pour l'assemblage des alliages de magnésium dans le cadre d'une production en
masse. En effet, des travaux récents menés à l'université du Wisconsin et ayant consisté à déposer des passes sur des tôles
en alliages de magnésium ont montré que :
- le problème des fortes projections générées lors du soudage de ces alliages peut être maitrisé en adoptant un transfert par
court-circuit contrôlé ;
- le problème des soufflure causé par l'azote peut être résolu en éliminant la couche de
Mg(OH)2 qui se forme naturellement avec le temps à la surface des fils-électrode.
La présente étude consista à effectuer des assemblages bout à bout et par recouvrement au
moyen de la méthodologie proposée. L'alliage AZ31, qui est actuellement le plus couramment
utilisé fut sélectionné pour les expérimentations. Des soudures saines furent obtenues, et les
caractéristiques mécaniques des assemblages s'avérèrent quasi équivalentes à celles du
matériau de base. Toutefois, de nouveaux problèmes affectant significativement la qualité des
soudures furent identifiés :
- la formation de films d'oxydes en soudage bout à bout ;
- la formation de surépaisseurs marquées en soudage bout à bout ;
- la formation de protubérances du cordon en soudage par recouvrement.
Soudure sur un assemblage
Ces trois nouvelles difficultés, tout comme celles identifiées précédemment, sont bien par recouvrement mettant en
évidence les protubérances
davantage liées aux particularités physico-chimiques du magnésium (faible densité à l'état ("fingers")
pouvant se former
liquide, faible tenue aux déformations à l'état solide, et forte affinité avec l'oxygène) qu'au
lors du soudage des alliages
de magnésium.
procédé de soudage. Des solutions permettant de parer à ces problèmes furent cependant
identifiées.
Gas metal arc welding of magnesium alloys: oxide films, high crowns, and fingers
The use of Mg alloys for vehicle weight reduction has been increasing rapidly worldwide. Gas metal arc welding (GMAW) has
the potential for mass-production welding of Mg alloys. Recently, the University of Wisconsin demonstrated in bead-on-plate
GMAW of Mg alloys that:
- the issue of severe spatter, which has long delayed the use of GMAW for Mg alloys, can be eliminated by using controlled
short circuiting (CSC),
- the issue of severe hydrogen porosity can be eliminated by removing Mg(OH)2, which forms on the welding wire surface
over time.
The present study aimed at actual butt and lap joint welding of Mg alloys by CSCGMAW. The most widely used wrought Mg
alloy AZ31 Mg (approx. Mg3Al1Zn0.2Mn) was welded by CSCGMAW. Sound welds were made without spatter and hydrogen
porosity, with butt joint welds approaching 100% of the base metal strength. However, three new significant issues were
found to occur easily and degrade the weld quality significantly:
- formation of oxide films inside butt joint welds,
- formation of high crowns on butt joint welds,
- formation of fingers from lap joint welds.
These three new issues, like the issues of spatter and porosity investigated previously, were caused mainly by the unusual
physical and chemical properties of Mg, rather than the welding process itself. These properties include the low liquid
density, low solid deformability, low liquid fluidity, and high oxygen affinity of Mg. The mechanisms of their formation were
established, and the methods for their elimination or reduction were demonstrated.
Auteur(s) : CHAI X., YANG Y.K., CARLSON B.E., KOU S.
Affiliation(s) : Department of Materials Science and Engineering, the University of Wisconsin, Madison, Manufacturing System Lab, General Motors
Research and Development Center, Warren
Pays : Etats-Unis
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Microstructure et caractéristiques mécaniques des assemblages à recouvrement aluminium/nickel
réalisés par soudage CMT
Microstructure and mechanical properties of cold metal transfer welded aluminium/nickel lap joints
Cold metal transfer (CMT) welding aluminium alloy to pure nickel using AlSi5 filler wire was investigated in this work. A
characterisation of microstructure reveals that Al and Ni could be successfully jointed by the CMT welding process. From the
Ni side to the Al side, the interfacial structure consisted of Ni substrate, Ni 3Al-Ni0.9Al1.1-Ni2Al3 intermetallic compound layer,
NiAl3 layer and Al-Si solid solution four parts. Moreover, the welding velocity had a significant influence on the interfacial
morphology of the Ni/Al joints. Shear tensile testing shows that maximum shear strength of 42 MPa was obtained at a
-1
welding velocity of 15 mm/s . Brittle fractures were observed in all of the lap joint specimens, with fractures located mainly
at the NiAl and NiAl3 intermetallic compound layer.
Auteur(s) : LIU Y.B., SUN Q.J., SANG H.B., FENG J.C.
Affiliation(s) : State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Shandong Provincial Key Laboratory of Special
Welding Technology, Harbin Institute of Technology at Weihai
Pays : Chine
Soudage par résistance
La productivité du procédé de soudage par résistance à la molette s'accroît grâce aux commandes
adaptatives
Pour réaliser des soudures parfaitement étanches avec le procédé de soudage par résistance à la molette, il faut que les
différents points de soudures se recouvrent correctement et que chaque point soit de qualité suffisante. Un apport d'énergie
insuffisant produira des points de soudure de dimensions insuffisantes, alors qu'à l'inverse, un excès de chaleur se traduira
par l'expulsion des soudures. De nombreux paramètres doivent donc être pris en compte pour parvenir au résultat escompté
: choix des matériaux constituant les électrodes, diamètre des électrodes, effort appliqué, courant électrique déployé et
temps de maintien notamment. L'ensemble de l'équipement utilisé pour la mise en œuvre du procédé doit parfaitement
fonctionner et être doté des outils et des composants appropriés afin d'assurer la reproductibilité des opérations de
soudage. Les systèmes de commandes doivent permettre un ajustement assez fin des différents variables, toute variation
d'un seul de ces paramètres se traduisant immédiatement sur le résultat final. Cet article montre justement comment les
récentes avancées dans le domaine des commandes numériques permettent de réenvisager la mise en œuvre de ce procédé,
quelque peu tombé en désuétude, dans un contexte industriel productif.
Resistance seam welding throughput increases with adaptive controls
Making a gas-tight seal with a seam welding machine involves making a series of overlapping spots. Each spot produced
should be a fully formed nugget that is free of expulsion. Using too little heat produces an undersized spot, which can cause a
leak. Using too much heat produces expulsion, which can also cause a leak. In addition to controlling the formation of each
nugget, sufficient control of the spot spacing must be maintained to ensure each nugget overlaps with the next. Each
precision spot welding application generally requires selecting the correct material electrodes along with the right electrode
face diameter, electrode force, current, and amount of time. A capable machine with proper tooling is required to maintain
control of the electrode contact area on the part and apply electrode force that is repeatable from weld to weld. A capable
control is required to provide accurate delivery of the programmed current for each weld. Variation in any of these
parameters will vary the spot welding results. A spot welding machine may be used to make a gas-tight seal by making a
weld, lifting the electrodes off the part, moving the part a specified distance, bringing the electrodes back onto the part to
make another weld, and repeating that process until the desired length seam is produced. Spot spacing must be accurately
controlled to ensure each spot produced sufficiently overlaps with the next.
Auteur(s) : COHEN R.K.
Affiliation(s) : WeldComputer Corp., New York
Pays : Etats-Unis
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Un traitement thermique après soudage innovant pour l'amélioration des caractéristiques
mécaniques des assemblages soudés par résistance par points
Novel postweld heat treatment method for improving mechanical properties of resistance spot weld
A novel postweld heat treatment method by applying cross-direction welding current (crosscurrent) was applied on the
resistance spot weld. The effect of cross-current on the nugget shape, microstructure and mechanical properties was
investigated. The results show that the cross-current postweld heat treatment enhances the efficiency of postweld heat
treatment and improves the mechanical performance of nugget. The cross-current promotes the recrystallisation of nugget
microstructure, which induced the transformation of microstructure from column crystal to quasi equiaxed grain. The
quasiequiaxed grains of martensite in the weld nugget significantly increase the microhardness of weld nugget and the
tensile shear force of weld joint.
Auteur(s) : DUAN R., LUO Z., LI Y., ZHANG Y., LIU Z. M.
Affiliation(s) : School of Materials Science and Engineering, Tianjin University, Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University
Pays : Chine
Profils de températures à l'interface des joints lors de la simulation du soudage par résistance par
points d'aciers zingués et d'aciers non-revêtus
Interfacial temperature profiles in simulated resistance spot welding of bare and zinc coated steel
For better understanding of basic phenomena of resistance spot welding, temperature profiles were measured by monitoring
the infrared emissions at 5 kHz from one dimensionally simulated welding of sheet metal disks between the electrodes of a
resistance spot welding machine. The weld variables included the zinc coating thickness, coating morphology, workpiece
thickness, and electrode force. For a given tap and heat control setting in the welding machine, as the coating thickness
increased, the induced welding current increased due to a lower contact resistance created by the molten zinc layer.
However, the temperatures experienced by the workpiece and electrode decreased. This was due to a decreased power
absorption of the materials with lower electrical resistance of thicker coatings and the electrical characteristics of the spot
welding machine. The temperature differences in welding of materials with different coating morphologies and specimen
thicknesses are most pronounced at the faying interface. As the electrode force increased, the temperature differences
between the materials decreased due to the decreased effect of the contact characteristics. The thicker material of bare steel
became less sensitive to the contact characteristics as the electrode force increased. This was due to the decreased ratio of
contact resistance to the total resistance. Thinner materials experience faster temperature rise and lose more heat to the
electrodes.
Auteur(s) : KIM E., EAGAR T.W.
Affiliation(s) : Department of Systems Engineering, Ajou University, Suwon Massachusetts Institute of Technology, Cambridge
Pays : Etats-Unis
Soudage par étincelage
Microstructure et tendance à la rupture des assemblages d'aciers dissemblables réalisés par
soudage en bout par étincelage
Microstructure and fracture behaviour of flash butt welds between dissimilar steels
Flash butt welds between high carbon steel and chrome–nickel steel were studied in this article. Light and electron
microscopic studies have shown that the welded joints have a complex structure consisting of several phases. In addition to
pearlite colonies, austenite microvolumes and regions of high strength martensite, the welds contain brittle inclusions of
titanium sulphide and carbide particles. The mechanical behaviour of the welded joints is negatively influenced by the
dramatic change in hardness in the weld zone. Fractographic analysis of dynamically fractured welds between carbon steel
and stainless steels has shown that the fracture in the weld samples occurs in both steels. This behaviour of the material is
caused by the non-uniform distribution of martensitic regions within the weld. The formation of martensitic regions in the
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structure of the material is a major cause of the reduction in the fatigue crack resistance of the welded joints.
Auteur(s) : NIKULINA A.A., BATAEV A.A., SMIRNOV A.I., POPELYUKH A.I., BUROV V.G., VESELOV S.V.
Affiliation(s) : Novosibirsk State Technical University
Pays : Russie
Soudage par friction
Simulation physique de l'évolution de la microstructure des assemblages soudés en alliage Ti-6Al4V réalisés par friction linéaire
Physical simulation of microstructural evolution in linear friction welded joints of Ti-6Al-4V alloy
The novel shear compression specimen was used to simulate the microstructural evolution in linear friction welding joints of
Ti-6Al-4V alloy. Similar formation mechanisms of microstructures and microtextures were found in the linear friction welding
joints and shear compression specimen. Accordingly, the shear compression test was proved to simulate the microstructural
evolution and the thermomechanical conditions that occurred in linear friction welding joint. Furthermore, the strain rate in
linear friction welding was estimated to exceed the value of 70s [-]1.
Auteur(s) : JING L., FU R.D., LI Y.J., SHI Y., WANG J., DU D.X.
Affiliation(s) : State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, College of Materials Science and Engineering,
Yanshan University
Pays : Chine
Soudage par friction-malaxage
Etude paramétrique du procédé de soudage par friction-malaxage par points avec une tête de
soudage sans pion appliqué à l'alliage d'aluminium 5754
Parametric study of FSSW of aluminium alloy 5754 using a pinless tool
A parametric study of friction stir spot welding (FSSW) of lap joints in aluminium alloy 5754 using a pinless tool with scrolled
shoulder is presented. Experimental plan was done according to the response surface methodology (RSM), where tool
rotation speed varied between 988 and 3511 rev/min, plunge rate between 24.4 and 150 mm/min and dwell time between 1
and 3.5 s. The plunge depth was held constant at 0.4mm. During welding, the axial force and torque were monitored using a
dynamometer. The welds were tensile shear tested, and the broken samples were visually examined. The weld bond line and
microstructure were analysed using light optic microscope under polarised light, and SEM was used for examination of
fractured surface. Mathematical models describing the relationship between welding parameters and joint strength, axial
force and torque were developed. FSSW parameters, at which maximal joint strength was obtained, were considered as
optimal. At these welding parameters, the axial force and torque were in the lower range among tested parameters. Material
flow and joint formation are experimentally presented and schematically illustrated.
Auteur(s) : KLOBCAR D., TUSEK J., SMOLEJ A., SIMONCIC S.
Affiliation(s) : Faculty of Mechanical Engineering, University of Ljubljana
Department of Materials and Metallurgy, Faculty of Natural Sciences, University of Ljubljana
Pays : Slovénie
Cote ISDOC : WW201502.269-281
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Amélioration des caractéristiques mécaniques d'assemblages de laitons 70/30 réalisés par frictionmalaxage multipasse avec refroidissement rapide
Enhanced mechanical properties of 70/30 brass joint by multi-pass friction stir welding with rapid cooling
70/30 (Cu/Zn) brass plates with a 2 mm thickness were jointed by repeated rapid cooling friction stir welding. The joints from
each FSW cycle showed the typical construction of a microstructure which includes the stir zone and the thermomechanically affected zone, but the morphology and boundary characteristics in these zones changed with the different
cycles. In the stir zone, the grain size decreased and the number fraction of the high angle boundaries increased with the
increasing number of FSW cycles. The texture analysis suggested that the post-annealing effect, which frequently occurred
after the FSW process, was remarkably restricted by the liquid CO2 cooling, which accelerated the refinement of the
microstructure. As a result, a joint with an ultrafine grained structure (0.8 [mu]m) and an excellent strength ductility
matching (548 MPa and 34% respectively) can be achieved by multi-pass rapid cooling FSW process.
Auteur(s) : XU N., UEJI R., FUJII H.
Affiliation(s) : Joining and Welding Research Institute, Osaka University
Pays : Japon
Clarification de l'écoulement de matière et de la formation de défauts en soudage par frictionmalaxage
Clarification of material flow and defect formation during friction stir welding
The defect formation mechanism during friction stir welding (FSW) was investigated by the three dimensional visualisation of
material flow around a tool. The three-dimensional flow patterns under various FSW conditions were obtained using two
pairs of X-ray transmission real time imaging systems. The flow patterns revealed that the tilt of horizontal material flow
around the tool and the stagnation of material flow on the advancing side (AS) of the tool were significantly correlated to the
formation of defects. The material flow velocity during FSW was directly calculated based on the results of three-dimensional
visualisation. The material flow velocity on the AS obviously decreased under the condition where defects were formed.
Auteur(s) : MORISADA Y., IMAIZUMI T., FUJII H.
Affiliation(s) : Osaka University
Pays : Japon
Caractérisation du procédé de soudage par friction-malaxage par points basée sur l'analyse de
l'enveloppe de signaux vibro-acoustiques
Characterisation of friction stir spot welding process based on envelope analysis of vibro-acoustical signals
The evaluation of the relationship between the vibro-acoustical signals generated by friction stir spot welding (FSSW) process
with its parameters and stages such as torque, dwell time, and tool rotation speed, is developed in this work. A dissimilar lapjoint was conducted using pure copper and AA1050 H24 aluminium alloy. The vibro-acoustical signals in Z and Y directions,
and torque applied by the tool during the process have been acquired by the instrument NI USB-9234. The characterisation in
the time and frequency domains of the vibro-acoustical signals has been performed in order to correlate them with the
stages of processing and tool torque. The analysis has confirmed that the vibro-acoustical signals were significantly affected
by changes in process forces and can thus be used as a non-destructive method for process monitoring, optimisation tasks,
and control of FSSW process.
Auteur(s) : MACIAS E.J., ROCA A.S., FALS H.C., MURO J.C.S., FERNANDEZ J.B.
Affiliation(s) : Department of Electrical Engineering, University of La Rioja, Faculty of Mechanical Engineering, University of Oriente
Pays : Espagne, Cuba
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Soudage par friction-malaxage assisté par ultrasons de l'alliage d'aluminium 6061
Ultrasonically assisted friction stir welding of aluminium alloy 6061
Ultrasonically assisted friction stir welding (UAFSW) was explored. Metallographic structures and material flow prepared by
UAFSW were compared with those prepared by conventional FSW. Hardness curves, tensile strength, and elongation of
welds fabricated at different ultrasonic powers were characterised. Experimental results showed that hardness curves,
tensile strength of welds increased with increased ultrasonic power when it was less than 50%. The elongations decreased
with ultrasonic energy output increased. Scanning electron microscopy photographs in different positions of fracture by
UAFSW show fracture pattern and origin.
Auteur(s) : MA H.K., HE D.Q., LIU J.S.
Affiliation(s) : College of Mechanical and Electrical Engineering of Central South University
Pays : Chine
Recours au soudage par friction-malaxage pour la réalisation d'assemblages dissemblables entre
alliage d'aluminium (6111) et thermoplastiques
Dissimilar joining between aluminium alloy (AA 6111) and thermoplastics using friction stir welding
In this work, friction stir welding was used to produce shear overlap joints between aluminium and a thermoplastic (AA 6111
to polyphenylene sulphide). The process uses the friction stir welding tool to create metallic chips which merge with the
molten thermoplastic to form a joint. No special surface pretreatment is required before joining. Cross-sections show
mechanical locking between the chipped polymer filled zone and the surrounding aluminium sheet. The effects of joining
parameters such as rotational speed, translational speed and distance to backing were investigated in relation to the joint
strength and failure mode. Optimum speeds and backing distances could be identified. The joint strength is dominated by
mechanical interlocking between the chip and polymer filled zone and the aluminium sheet.
Auteur(s) : RATANATHAVORN W., MELANDER A.
Affiliation(s) : Department of Production Engineering, School of Industrial Engineering and Management, KTH-Royal Institute of Technology, Swerea
KIMAB AB
Pays : Suède
Influence d'un traitement thermique après soudage sur la microstructure et les caractéristiques
d'assemblages en acier 32Mn-7Cr-1Mo-0,3N réalisés par friction-malaxage
Effect of post-weld heat treatment on microstructures and properties of friction stir welded joint of 32Mn-7Cr-1Mo-0.3N
steel
In this study, the microstructures and mechanical properties of friction stir welded and post-weld heat treated joints of
32Mn-7Cr-1Mo-0.3N steel were investigated. Significant microstructural and mechanical property gradients were found
along the transverse directions of the as welded joint. These gradients led to overmatching characteristic with higher
strength but lower ductile than base material. The post-weld heat treatment effectively reduced the gradient characteristics
in the as welded joint. Consequently, the mechanical property of the joint was nearly restored to the level of base metals.
However, the abnormal grain growth was observed in the heat affected zone of the post-weld heat treated joint. The
possible mechanism was discussed in term of the evolution of atom segregation at grain boundaries.
Auteur(s) : LI Y.J., FU R.D., DU D.X., JING L.J., SANG D.L., WANG Y.P.
Affiliation(s) : State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, College of Materials Science and Engineering,
Yanshan University
Pays : Chine
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Stabilité des précipités de type Y-Ti-O dans les assemblages en alliages ferritiques nanostructurés
réalisés par friction-malaxage
Stability of Y-Ti-O precipitates in friction stir welded nanostructured ferritic alloys
Nanostructured ferritic alloys, which have complex microstructures consisting of ultrafine ferritic grains with a dispersion of
stable oxide particles and nanoclusters, are promising materials for fuel cladding and structural applications in the next
generation nuclear reactor. This study evaluates microstructure of friction stir welded nanostructured ferritic alloys using
electron microscopy and atom probe tomography techniques. Atom probe tomography results revealed that nanoclusters
are coarsened and inhomogeneously distributed in the stir zone and thermos-mechanically affected zone. Three hypotheses
on coarsening of nanoclusters are presented. The hardness difference in different regions of friction stir weld has been
explained.
Auteur(s) : YU X., MAZUMDER B., MILLER M.K., DAVID S.A., FENG Z.
Affiliation(s) : Materials Science and Technology Division, Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge National
Laboratory
Pays : Etats-Unis
Développement d'un équipement de soudage par friction-malaxage de petites dimensions actionné
manuellement
Le soudage par friction-malaxage est désormais largement utilisé dans divers secteurs de l'industrie. Les équipements utilisés
doivent toutefois être en mesure de supporter les efforts importants appliqués lors de la mise en œuvre du procédé, ce qui
explique qu'ils deviennent rapidement lords et volumineux. Dès lors, il est difficile d'envisager une mise en œuvre sur site du
soudage par friction-malaxage ; idem pour les opérations de réparation par soudage. Les auteurs de cette étude proposent
un équipement novateur, doté de dispositifs permettant d'une part un chauffage localisé des matériaux de base et d'autre
part, de contrebalancer les charges. Ils ont étudié la relation entre effort appliqué et paramètres de soudage et ont pu
démontrer que l'approche qu'ils proposent permet de réduire l'effort appliqué dans le sens du soudage (Fx) jusqu'à 70 N, et
l'effort appliqué transversalement (Fy) jusqu'à 50 N voire moins. Il leur fut ainsi possible de réduire fortement les dimensions
de l'équipement de soudage par friction-malaxage.
Development of small sized friction stir welding equipment for hand operated weld
Friction stir welding (FSW) is widely used in various industrial fields. However, high stiffness is required for FSW equipment
which has to withstand high applied load and tool torque and therefore, the equipment becomes large sized. It is difficult to
employ FSW for site welding such as repair welding and/or manual welding. The authors made a prototype of FSW apparatus
equipped with a counterbalanced tool and a local heating device. The relationship between the applied load and welding
parameters was investigated and it was found that the force in the welding direction, Fx is reduced to 70 N or less and that in
the transverse direction Fy is to 50 N or less. The combined use of the prototype equipment with a counterbalanced tool and
the local heating is very effective to downsize FSW equipment.
Auteur(s) : MORISADA Y., TAMASHIRO K., KAMAI M., UEJI R., FUJII H.
Affiliation(s) : Joining and Welding Research Institute, Osaka University
Pays : Japon
Examen de la microstructure et caractéristiques mécaniques d'assemblages constitués de nuances
dissemblables d'alliage de magnésium réalisés par friction-malaxage
Microstructural investigation and mechanical properties of dissimilar friction stir welded magnesium alloys
Dissimilar joints of magnesium alloys were obtained by friction stir welding. Detailed microstructure and texture
examinations were performed on the joints. Significant difference in microtexture distribution and microstructural features is
observed between crown and stir zones in the dissimilar joints. However, an overall effect of these factors on mechanical
properties of layered joints is not obvious as both the up and middle samples present quite similar yield strength and strain
hardening behaviour. Moreover, both samples fracture in the Mg-3Al-1Zn alloy side. The fracture of the middle sample starts
at the boundary of transition and stir zones, while the up sample starts in the crown zone side.
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Auteur(s) : LIU Z., LIU D., XU J., ZHENG X., LIU Q., XIN R.
Affiliation(s) : College of Materials Science and Engineering, State Key Laboratory of Mechanical Transmission, Chongqing University
Pays : Chine
Soudage par friction-malaxage d'assemblages dissemblables aluminium/magnésium : influence de
la position relative des pièces
Friction stir welding of dissimilar aluminium-magnesium joints: sheet mutual position effects
Friction stir welding (FSW) is a solid state welding process used to weld difficult to be welded or unweldable materials as
aluminium alloys. In the last years, other materials have been successfully tested as magnesium, titanium and nickel based
alloys. Dissimilar joints can be obtained by FSW, but issues arise concerning the correct choice of the process parameters. In
the paper, the results of an experimental and numerical campaign aimed to produce dissimilar AZ31-AA6016-T6 butt joints
are presented. The effect of sheet mutual position and main process parameters was investigated. It was found that
intermetallics are the main cause of the poor quality of the joints. Sound joints can be produced only if the magnesium alloy
is in the advancing side.
Auteur(s) : BUFFA G., BAFFARI D., DI CARO A., FRATINI L.
Affiliation(s) : University of Palermo
Pays : Italie
Complétion du trou laissé lors de la mise en œuvre du procédé de soudage par friction-malaxage à
l'aide d'un outil disposant d'un pion consommable
Filling exit holes of friction stir welding lap joints using consumable pin tools
In this study, filling friction stir welding was used to remove the exit hole of friction stir welding lap joints made from AA5456
sheets. For this purpose, the exit holes were filled by consumable pins with various geometries and different pin applying
methods. Then, the structures and mechanical properties of the resulting joints were investigated. Results showed that the
strength of 7% higher than the strength of the joint with the non-filled exit hole, approx. 91% of the corresponding defect
free joints, is obtainable with this technique. The best results were found by a pin with 118 cone angle, 8 mm diameter and 7
mm length, and with a 6 mm plunge without rotation.
Auteur(s) : BEHMAND S.A., MIRSALEHI S. E., OMIDVAR H., SAFARKHANIAN M.A.
Affiliation(s) : Department of Mining and Metallurgical Engineering, Amirkabir University of Technology (AUT), Department of Materials Science, Majlesi
Branch, Islamic Azad University
Pays : Iran
Amélioration de la macrosection, de la microstructure et des caractéristiques mécaniques des
assemblages bout à bout en alliage d'aluminium 2024-T4 réalisés au moyen du procédé de soudage
par friction-malaxage amélioré par ultrasons
Improved weld macrosection, microstructure and mechanical properties of 2024Al-T4 butt joints in ultrasonic vibration
enhanced friction stir welding
Ultrasonic vibration enhanced friction stir welding (UVeFSW) is a new variant of friction stir welding (FSW) in which a
sonotrode transmits ultrasonic energy directly into the localised area of the workpiece near and ahead of the rotating tool.
This study investigated the influence of ultrasonic vibration on the formation, microstructure and mechanical properties of
butt welded 2024Al-T4 joints, and attempted to unveil the underlying mechanism of UVeFSW by experimental methods.
Morphology inspection, X-ray detection and metallographic inspection of the welds revealed that ultrasonic vibration can
improve the weld formation at higher welding speeds. The stir zone in the UVeFSW broadened, while the grains in the heat
affected zone had no obvious growth contrary to that in the base metal. Results of the mechanical tests indicated that the
tensile strength and elongation of joints, and the microhardness value in the stir zone increased at the same welding
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parameters.
Auteur(s) : LIU X.C., WU C.S., PADHY G.K.
Affiliation(s) : MOE Key Lab for Liquid-Solid Structure Evolution and Materials Processing and Institute of Materials Joining, Shandong University
Pays : Chine
Soudage hybride
Etude sur les mécanismes d'un procédé de soudage hybride TIG-MIG
Lors de la mise en œuvre d'un procédé hybride TIG-MIG (torche TIG en courant continu et polarité négative et torche MIG en
courant continu et polarité positive), la stabilité de l'arc MIG peut être assurée même sous atmosphère totalement inerte
grâce aux effets synergiques de l'arc TIG, et l'hybridation des procédés permet de tirer le meilleur parti de chacun d'eux
(qualité des soudures TIG et productivité du procédé MIG). Durant cette étude deux expérimentations furent menées pour :
- démontrer qu'un courant continu circule entre la cathode TIG et
l'anode MIG au travers d'un plasma d'arc hybride ;
- mesurer l'apport d'énergie réel sur la base de la quantité d'azote qui
s'évapore afin de caractériser avec précision la source de chaleur.
Ces travaux permirent de constater que l'énergie libérée par la source
TIG est moindre en mode hybride et que l'apport de chaleur se trouve
diminué de 10 % par rapport aux procédés TIG et MIG conventionnels.
De plus, dans certaines conditions spécifiques, il fut constaté que la
valeur du courant TIG est moindre que celle du courant MIG ; en sortie
de générateur, cette valeur peut même être nulle alors que l'arc TIG
reste nettement observable. Cependant l'arc MIG devient alors instable.
Il ressort de cette étude qu'un courant continu est bien généré entre les
deux torches et que la torche TIG permet bien de contrôler la stabilité de
l'arc MIG.
Study for the mechanism of TIG-MIG hybrid welding process
On TIG-MIG hybrid welding process (TIG: DCEN and MIG: DCEP), the
Différence de stabilité entre soudage MIG conventionnel
et soudage hybride TIG -MIG sous protection gazeuse
stability of MIG arc can be kept even in pure inert shielding gas by the
d'argon (acier inoxydable 304 d'épaisseur 12 mm, vitesse
effect of hybridization with TIG arc, and it becomes possible to achieve
d'avance de 30 cm/min). Le graphique signalé par
l'astérisque représente la forme d'onde du courant MIG.
the new welding method which has both merits of high quality as TIG
welding process and high efficiency as MIG welding process. In this report, we performed two experiments mainly as follows
to solve two problems:
- Analysis of output from TIG power source in hybrid welding state to prove experimentally the existence of direct current
path which flows between TIG cathode and MIG anode via in hybrid arc plasma.
- Measurement of actual heat input based on evaporation amount of liquid nitrogen to investigate detailed heat source
property of this process.
As results, it was shown that output of TIG power source in hybrid welding condition is lower than it in single TIG welding,
and the heat efficiency in hybrid welding condition decreases about 10 % rather than it in single heat source of TIG or MIG
arc. Moreover, in specific condition that value of TIG current is lower than value of MIG current, output of TIG power source
becomes entirely zero even though TIG arc shape is observed clearly, and thus, the stability of MIG arc is lost then. It can be
said that these findings reveal the existence of direct current and explain one of mechanisms that TIG arc can control the arc
stability and heat input of MIG arc.
Auteur(s) : KANEMARU S., SASAKI T., SATO T., ERA T., TANAKA M.
Affiliation(s) : TAIYO NIPPON SANSO Corporation, DAIHEN (OTC) Corporation, Osaka University
Pays : Japon
Cote ISDOC : WW201502.261-268
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Soudage laser
Projections générées lors du soudage laser avec oscillation du faisceau
Spatter formation in laser beam welding using laser beam oscillation
This paper presents an approach towards a better understanding of spatter formation in laser beam welding. Hereunto,
experimental investigations and numerical simulation are carried out. For the study, various steels and aluminium alloys were
selected to investigate the influences of alloying elements upon spatter formation. The welding was performed by applying a
laser beam oscillation technique in which weld seam is generated by a spiral movement of the laser beam, in order to check
the influence of weld pool movement according to spatter formation. This strategy was also transferred to the numerical
simulation to get a detailed insight into the processes taking place in the keyhole when spatters form. Furthermore, a new
detection method is presented which allows a three-dimensional tracking of spatters by using a pair of synchronised stereo
cameras.
Auteur(s) : HUGGER F., HOFMANN K., KOHL S., DOBLER M., SCHMIDT M.
Affiliation(s) : Bayerisches Laserzentrum GmbH, University of Erlangen-Nuremberg, SAOT
Pays : Allemagne
Cote ISDOC : WW201502.165-172
Influence de la composition chimique sur la microstructure et les caractéristiques mécaniques du
métal fondu lors du soudage laser d'un acier à haute résistance
Effect of chemical composition on microstructure and mechanical properties of laser weld metal of high-tensile-strength
steel
Laser beam welding (LBW) and laser-arc hybrid welding are expected to be applied to welding of high-strength steel plates
over 780 MPa, because they have advantages such as low distortion and a narrow heat-affected zone. This research
examined the relationship between the chemical composition of high-strength steel plates and the microstructure and
mechanical properties of the weld metal with the aim of improving the toughness of welded joints of high-strength steels by
the LBW process. The results revealed that weld metal toughness is strongly dependent on the carbon (C) content of the
steel plates, and excellent toughness can be obtained in weld metals with low C contents having an almost fully lower bainite
structure without formation of slender martensite austenite constituent (MA). Based on these results, a guideline for
appropriate alloying element design for high strength steels for LBW was proposed, targeting mechanical properties of
tensile strength ≥ 980 MPa and toughness vE - 40 °C ≥ 47 J.
Auteur(s) : SUMI H., OI K., YASUDA K.
Affiliation(s) : JFE Steel Corporation
Pays : Japon
Cote ISDOC : WW201502.173-178
Souder l'aluminium en combinant un laser à diode et un laser Nd:YAG pulsé
Aluminum welding by combining a diode laser with a pulsed Nd:YAG laser
Laser welding of aluminum alloys (AA 5754 and AA 6016) by superimposing a pulsed Nd:YAG laser with a continuous wave
(cw) diode laser has been investigated in order to improve the weldability and the process efficiency. The low absorption of
laser radiation at a wavelength of 1064 nm and the high thermal conductivity make it difficult to laser weld aluminum alloys
efficiently. Therefore, a pulsed Nd:YAG laser and a low power diode laser emitting a wavelength of 980 nm were spatially
superimposed. This configuration allows to enhance the absorption for the Nd:YAG welding laser due to the preheating of
the diode laser. Thus, the process efficiency as well as the weld quality is enhanced. The experiments revealed that a small
output power of the diode laser (inf. 150 W) allows increasing the welding speed up to 80 % and the weld depth up to 38 %.
Furthermore, the superposition leads to a significant improve of the weld seam quality, in particular to avoid hot cracking.
Auteur(s) : BERGMANN J.P., BIELENIN M., FEUSTEL T.
Affiliation(s) : Technische Universität Ilmenau
Pays : Allemagne
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Cote ISDOC : WW201502.307-315
Soudage laser en mode keyhole de plusieurs épaisseurs de tôles fines en acier inoxydable pour la
fabrication de piles à combustible
Laser keyhole welding of stainless steel thin plate stack for applications in fuel cell manufacturing
An investigation based on both experimental and numerical approaches is presented in this paper on laser keyhole welding
processes to join stacks consisting of multiple stainless steel plates. The welding parameters are shown to be decisive factors
for weld penetration depth and welding productivity. The cooling rate varies with welding parameters and the location of
solidification sites, and it directly determines the primary dendrite arm spacing for the columnar dendrites inside the weld
zone. The joint fails in coach peel tests when the loading pressure is 93.4 MPa, and the fracture surface shows a mixed brittle
and ductile mode. The corrosion resistance of the weld to the polymer electrolyte membrane fuel cell working environment
is comparable to that of the substrate.
Auteur(s) : TAN W., SHIN Y.C.
Affiliation(s) : Center for Laser Based Manufacturing, Purdue University
Pays : Etats-Unis
Atténuation des défauts formés à la racine des joints en soudage laser et soudage hybride laserarc
Mitigation of root defect in laser and hybrid laser arc welding
Even though laser and hybrid laser arc welding processes can produce single pass, complete joint penetration welds in excess
of 12 mm, root defects, such as root humping, have been observed at these greater plate thicknesses. The competition
between the surface tension and the weight of the liquid metal in the weld pool is expected to govern root defect formation.
A series of laser and hybrid laser gas metal arc welds has been completed in which each force is independently varied. The
internal morphologies of the resulting root defects are characterized by X-ray computed tomography and found to vary
significantly when welding with either the laser or hybrid laser arc process. In order to compute the surface tension and
liquid metal weight, a model based on the approximate geometry of the weld pool is developed and successfully predicts the
range of processing conditions where root defects form. Process maps are then constructed for low-carbon steel and 304
stainless steel alloy systems. These maps can then be used to select welding parameters that produce defect free complete
joint penetration welds over a wide range of plate thicknesses.
Auteur(s) : BLECHER J.J., PALMER T.A., DEBROY T.
Affiliation(s) : Department of Materials Science and Engineering, Applied Research Laboratory, The Pennsylvania State University, University Park
Pays : Canada
Soudage sous eau
Etude préliminaire sur le soudage pleine eau avec chauffage par induction en temps réel
Preliminary investigation on real-time induction heating-assisted underwater wet welding
A novel real-time induction heating assisted underwater wet welding process was investigated. The addition of induction
heating could reduce the cooling rate of the joint in underwater wet welding. The macro and microstructures, mechanical
properties such as tensile, impact, and bending properties, and Y-slit restraint testing were studied. The results showed the
content of martensite (M) and upper bainite (BU) phases decreased, while the proeutectoid ferrite (PF) and acicular ferrite
(AF) phases increased as the induction heating voltage increased. Mechanical properties of the joint were improved through
addition of induction heating and fracture morphology with characteristic uniform dimples belonging to ductile fracture. The
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cracking ratio of Y-slit restraint testing was also decreased. Therefore, the susceptibility to cold cracking of the wet welding
joint was improved.
Auteur(s) : ZHANG H.T., DAI X.Y., FENG J C., HU L.L.
Affiliation(s) : Welding and Joining, Harbin Institute of Technology, Shandong Provincial Key Laboratory of Special Welding Technology, Weihai
Pays : Chine
Soudage par explosion
Mécanismes de formation de joints de haute qualité en acier inoxydable martensitiques assemblés
par diffusion
Formation mechanisms of high quality diffusion bonded martensitic stainless steel joints
Diffusion bonding of martensitic stainless steel was conducted at different times. Based on the interface characteristic and
shear strength, bonding mechanisms were discussed. Results showed that the bonding quality was controlled by void
shrinkage and interface grain boundary migration. Large voids with scraggly edges changed to small voids with smooth edges,
leading to an increase in interface bonding ratio. Two cases of interface grain boundary migration were revealed: interface
grain boundary migration at the triple junction induced by the reduction in grain boundary energy and strain induced
interface grain boundary migration resulted from the stored energy. Owing to the void shrinkage and interface grain
boundary migration, the shear strength of the joint matched that of the base material.
Auteur(s) : ZHANG C., LI H., LI M. Q.
Affiliation(s) : School of Materials Science and Engineering, Northwestern Polytechnical University
Pays : Chine
Produits d'apport
Caractéristiques et soudabilité de nuances modifiées de fils d'apport à basse température de
transformation de phase
Properties and weldability of modified low transformation temperature filler wires
Low transformation temperature (LTT) alloys allow to control residual stresses already during the welding process. Especially
high-strength structural steel applications may benefit from the LTT effect as they are sensitive to residual stresses due to a
limited ductility. Within this study, two modified LTT alloys were tested concerning their weldability under varying conditions.
Beside the transformation behavior, basic material properties were determined from all weldmetal. Hot cracking as well as
cold cracking susceptibility was evaluated using specific tests. The materials’ capability for residual stress control was
characterized by online measurements of the occurring loads during double-sided multipass fillet welding in a special test
facility. Varying heat control parameters were found to affect the stress buildup significantly. In the specific case, the results
revealed that higher working temperatures may favor lower stress buildup despite the higher overall heat input. Local
residual stress measurements using X-ray diffraction support this finding.
Auteur(s) : KROMM A., VAN DER MEE V., KANNENGIESSER T., KALFSBEEK B.
Affiliation(s) : BAM Federal Institute for Materials Research and Testing, Berlin
Pays : Allemagne
Cote ISDOC : WW201503.413-425
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Evaluation de nouveaux produits d'apport sans argent pour le brasage
Evaluation of new silver-free brazing filler metals
TiBraze®LOK59-03 (Cu-40Zn-1Sn-0.3Si) filler metal provides the best combination of strength and flow as compared to
standard BAg-1 and BCuP-5 silver-containing filler metals. LOK59-03 is better suited to braze steels than the conventional
silver based BFM; it makes sound quality joints and can withstand high loads. LOK59-03 is recommended for industrial testing
and approval of brazing stainless steel and carbon steel. Unlike other copper-phosphorus filler metals, low-temperature silver
free filler metal TiBraze®P14 (Cu-4Sn-6P) provided sufficient strength of carbon steel brazed joints despite the iron phosphide
layer at the interface. However, this filler metal is not suitable for brazing nickel-plated carbon steel. Brazed lap joints of
steels manufactured using TiBraze®LOK59-03 exhibited ductile behavior under static tension loading due to formation of
relatively homogeneous microstructure of joint metal presented by copper- zinc solid solutions containing only approx.1% of
precipitated Cu3Sn phase. Partial dissolution of such components of stainless steel as chromium and nickel in the joint metal
also improves the strength of brazed joints. Despite of microstructure characterized by uniform distribution of copper-based
solid solution and fine-grained eutectic, steel brazed joints made with TiBraze®P14 do not possess ductility due to formation
of continuous iron phosphide layer along the steel interface.
Auteur(s) : DUFFEY M.J., MARCHAL J.T., LONEY M.R., ALEXANDROV B.T., SHAPIRO A.E.
Affiliation(s) : Engineering Program, The Ohio State University, Columbus, Titanium Brazing, Inc., Hilliard, Ohio
Pays : Etats-Unis
Procédés de soudage spéciaux
Modélisation des cycles thermiques et du grossissement des composés intermétalliques lors de
l'assemblage au moyen du procédé FMB (Friction Melt Bonding) d'un acier à ultra-faible teneur en
carbone à l'alliage d'aluminium 2024-T3
Modelling thermal cycles and intermetallic growth during friction melt bonding of ULC steel to aluminium alloy 2024-T3
Dissimilar materials, aluminium 2024-T3 and ultralow carbon steel, have been welded by a novel process called friction melt
bonding. A finite element thermal model is developed to predict temperature cycles and to estimate the fusion pool
geometry and the intermetallic bonding layer thickness. The total mechanical power input in pseudo-steady state is inferred
from in situ measurements at the tool torque and rotational speed. Temperature dependent properties, including the latent
heat of fusion, and proper contact conditions between the welded plates and the backing plate are included. Predicted
temperatures are in agreement with the measurements at various distances from the weld centreline. Molten pool
geometries and intermetallic thicknesses, whose control is crucial to insure good weld mechanical performances, are also in
accordance with the experimental observations.
Auteur(s) : CRUCIFIX S., VAN DER REST C., JIMENEZ-MENA N., JACQUES P.J., SIMAR A.
Affiliation(s) : Université catholique de Louvain, iMMC-IMAP
Pays : Belgique
Le soudage par décharge de condensateurs gagne en attractivité
The use of capacitor discharge welding is on the rise
The automotive industry in North America has been abuzz recently with talk about capacitor discharge (CD) welding. The
main reason is that the light-weighting necessary to achieve the U.S. Corporate Average Fuel Economy (CAFE) standards,
combined with the need for crash-testing robustness, has led to the adoption of increasing amounts of hot-stamped boron
steels in the manufacture of automobiles. These steels are often difficult to resistance weld efficiently as the strength of the
weld achieved is not always easy to measure (simple chisel testing doesn’t work well with such hard material), the welding
force is high (often previously used welding guns now have insufficient force), and the typically uneven aluminum-silicon
(AlSi) coating on the steel is particularly aggressive to shortening electrode life. Projection welding of forged projections into
the substrate is especially troublesome, largely because helpful literature is limited, and welding standards are nonexistent.
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In such cases, CD welding has proved to be efficacious in welding these boron steels in both the “as-received from the mill”
and the “hot stamped” condition, while being especially effective for fasteners.
Auteur(s) : SCOTCHMER N.
Affiliation(s) : Huys Industries, Ltd., Weston
Pays : Canada
Assemblage par diffusion
Mécanisme d'interaction entre les interstices et l'interface des joints de grains en assemblage par
diffusion
Interaction mechanism between void and interface grain boundary in diffusion bonding
The interaction process between void and migrating interface grain boundary (IGB) in the bonding interface of
1Cr11Ni2W2MoV steel joints produced by diffusion bonding has been examined, and the corresponding interaction
mechanism was analysed. The results showed that there were two cases occurring in void-IGB interaction by comparing the
IGB velocity with void velocity: if the IGB velocity exceeded the void velocity, the void would separate from the IGB and be
trapped inside the grain; otherwise, the void would attach to and migrate with the IGB. It was also found that the void-IGB
interaction was related to the radius of void. The bigger voids easily separated from the migrating IGB, while the smaller
voids tended to attach to it. The approximate theoretical values of critical radius of voids for separation/attachment were
derived, and they agreed well with the experimental values obtained.
Auteur(s) : ZHANG C., LI H., LI M. Q.
Affiliation(s) : School of Materials Science and Engineering, Northwestern Polytechnical University
Pays : Chine
Brasage fort
Microstructures des assemblages TiAl brasés avec produits d'apport de base Ti-Zr
Microstructures of the TiAl joints brazed with Ti-Zr-based filler metals
TiAl is brazed with Ti-Zr-Fe and Ti-Zr-Cu-Ni-Fe brazing foils at 1323 and 1373 K for 5 min. Ti-rich, Ti3Al, and white blocky Ti-ZrAl-Fe phase are found in the joint brazed with Ti-Zr-Fe filler metal at 1323 K. Ti2Al phase is formed with the improved brazing
temperature. When using Ti-Zr-Cu-Ni-Fe filler metal, the joints are mainly comprised of Ti-rich, Ti3Al, and Ti2Al and white
blocky Ti-Zr-Al-(Cu, Ni, Fe) phase. The joint widths and the size and amount of white blocky Ti-Zr-based phases in the center
of the joints are increased when the brazing temperature is increased. And under the same brazing condition, the joint width,
the size of Ti3Al and Ti-Zr-Al-(Cu, Ni, Fe) phase in the joint brazed with Ti-Zr-Cu-Ni-Fe filler metal, are larger than that of Ti-ZrFe filler metal. More TiAl base metal dissolved into the joint induces the wider joint and the higher concentration of element
Al in the joint, which lead to form Ti2Al phase. Too large size compounds such as Ti-Zr-based phases and Ti3Al would
deteriorate the joint property. A lot of these phases also might have a negative effect on the joint property.
Auteur(s) : YE L., XIONG H.P., HUAI J.F., CHEN B.
Affiliation(s) : Beijing Institute of Aeronautical Materials, Aviation Industry Corporation of China
Pays : Chine
Cote ISDOC : WW201502.201-208
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Comportement des couches d'oxydes sur aluminium lors de traitements thermiques et leur
influence sur la brasabilité
Behaviour of the aluminium oxide layer during heat treatment and the resulting effects on brazeability
During the last years, the trend to develop lighter products becomes more and more important in the automotive industry. In
case of reduction of the material thicknesses, the joining technologies become more important as well and lead to a request
for higher process reliability. This is also happening in the field of aluminium brazing with shielding gas. In the manufacturing
of aluminium heat exchangers as well as other components comprised of product line-up by BEHR, the automotive industry
systems partner, the NOCOLOK flux brazing technology (non-corrosive lok), i.e., the gas-shielded brazing of aluminium
materials, is consistently state of the art. To date, the joining of aluminium materials as necessary in the manufacturing
processes of aluminium products has always posed a challenge, due to aluminium’s high affinity for oxygen. The
implementation of fluxing agents during the aluminium brazing and soldering processes eliminates the formation of oxide
layers on the component surface, and surface reoxidation is prevented via a shielding-gas atmosphere. The said shielding-gas
atmosphere is provided using nitrogen. In practice, the build-up of humidity and oxygen content in the shielding-gas
atmosphere cannot be totally prevented. The increasingly complex brazing products require continuous brazing-process
improvements. In order to fulfil this requirement, sensitivity analyses relating to oxide layer build-up have been set up. In
particular, the impact of oxygen and humidity in the brazing protective atmosphere as well as the influence of humidity on
the aluminium surface are hereby closely examined. The retaining water model describes the interaction of the aluminium
surface and the process of water treatment and leads as a important key factor for a higher understanding of the behaviour
of the aluminium oxide during heat treatment and the resulting effect on brazeability.
Auteur(s) : LOHREY M., FUESSEL U., TUERPE M.
Affiliation(s) : MAHLE Behr GmbH
Pays : Allemagne
Cote ISDOC : WW201502.225-237
Influence de la couche intermédiaire de zinc sur la brasabilité de l'alliage de magnésium AZ31B
sur tôles fines d'acier
Effect of Zn interlayer on brazeability of AZ31B-Mg alloy to steel sheet
The brazeability of AZ31B-H24 magnesium alloy sheet to Zn electroplated, plain carbon steel sheet using an Mg-Al-Zn alloy
filler metal and a diode laser heat source has been investigated. While the Zn coating promoted good wetting between the
molten filler alloy and the steel sheet, it did not play a direct role in forming the final bond. Bonding between the magnesium
alloy and the steel was facilitated by the formation of two transition layers. First, a nanoscale layer of FeAl 3 phase formed on
the surface of the steel by diffusion of Al from the Mg-Al-Zn brazing alloy into the steel. Upon further cooling, nucleation and
growth of either α-MgzMgZn eutectic phases or Mg2(Al,Zn)3 phase occurred on the FeAl3 surface layer.
Auteur(s) : NASIRI A.M., ZHOU Y.
Affiliation(s) : Centre for Advanced Materials Joining, University of Waterloo
Pays : Canada
Un procédé de brasage pour la fabrication rapide de panneaux laminés constitués de tôles fines
Brazing process promises rapid processing of laminated thin-metal panels
This work studied the basic feasibility of conducting indirect resistance heated braze joints, which was developed as a
precursor to a full indirect resistance roll-brazing (RRB) process. Work was conducted in a number of steps. First, the
technology was demonstrated using repeated application of indirectly resistance-heated bars or elements. This process was
termed indirect resistance bar brazing. This approach was used for joining finite width panels. As part of the resistance bar
brazing process, the need for electrically isolated heating elements was identified. Material selection for the composite
(ceramic-metal-ceramic) heating element was done, and the assembly processes defined. This then became an enabler to
demonstrate the resistance bar brazing process. This process was used to produce preliminary technology demonstrator
samples. All results were then used to develop requirements for an indirect RRB variant of the technology. A pilot indirect
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RRB system was assembled complete with specially designed segmented refractory metal-based rolls. This system provided
demonstration for continuous brazing of a candidate three-high corrugated sandwich material. These studies demonstrated
the feasibility and potential for manufacturing continuously indirect roll-brazed sandwich products. However, this work is
preliminary and will require additional development for scaling to commercially viable products.
Auteur(s) : GOULD J., COX D.
Affiliation(s) : EWI, Columbus, Ohio, CellTech Metals, San Diego, Californie
Pays : Etats-Unis
Microstructure à l'interface d'assemblages dissemblables alliage de magnésium AZ1B / acier étamé
brasés au laser
Interfacial microstructure of laser brazed AZ31B magnesium to Sn-plated steel sheet
The brazeability of AZ31B-H24 magnesium alloy sheet to Sn-coated plain carbon steel sheet using a Mg-Al-Zn alloy filler metal
and a diode laser heat source has been investigated. While the Sn-coating promoted good wetting between the molten filler
metal and the steel sheet, it did not play a role in forming the final metallic bond. Its primary function appeared to be in
maintaining an oxide free steel surface until the molten Mg filler metal could come in direct contact with the steel surface. In
all cases, failure of transverse tensile shear test specimens of the joint occurred in the steel base metal. Metallic bonding
between the magnesium alloy and the steel was facilitated by the formation of two transition layers, including a Fe(Al) solid
solution formed on the surface of the steel and a nano-scale layer of Al8(Mn,Fe)5 phase on the Fe(Al) surface layer.
Examination of the Fe(Al)-Al8(Mn,Fe)5 and Al8(Mn,Fe)5-Mg interfaces using HR-TEM showed that orientation relationships
(OR) with a low angle of rotation of the matching planes and low inter-planar mismatch and therefore low interfacial energy
density existed at the Fe(Al) Al8(Mn, Fe)5 interface and a high angle of rotation of the matching planes and large inter-planar
mismatch, and therefore, high interfacial energy density existed at the Al 8Mn5-Mg interface. These results were further
validated using an edge-to-edge crystallographic matching model of the Fe(Al)Al8( Mn,Fe)5 and Al8(Mn,Fe)5-Mg interfaces.
Auteur(s) : NASIRI A.M., WECKMAN D.C., ZHOU Y.
Affiliation(s) : Department of Mechanical & Mechatronics Engineering, Center for Advanced Materials Joining, University of Waterloo
Pays : Canada
Brasage tendre
Caractérisation et cinétique de formation de composés intermétalliques à l'état liquide lors du
brasage tendre avec produits d'apport sans plomb
Characterization and growth kinetics of the formation of intermetallic compounds in the liquid state during soldering with
lead-free solders
The research described in this paper developed the experimental techniques necessary for promoting intermetallic layer
growth throughout the melting and solidification cycle of the solder and then measuring the thickness of these layers. Most
of the literature to date reported on aged soldered joints to investigate in-service intermetallic layer growth. To observe
intermetallic compound (IMC) growth during the liquid state of soldering required an experimental setup that quickly raises
the temperature of the solder joint followed by fast cooling (comparable to the actual joint conditions). Temperatures at
increments of 25° above the soldering temperature and times of 2, 5, and 8 s for growth were carefully controlled. After the
experiments, the copper substrate/solder alloy interface was examined using light microscopy, scanning electron microscopy
(SEM), and SEM-EDS (energy dispersive spectroscopy). As expected, intermetallic phases such as Cu 6Sn5, Cu3Sn, and Ag3Sn
were observed, with Cu6Sn5 being the major phase. Statistical analysis was performed for the IMC thickness data obtained
from the long profile analysis. Empirical equations capable of predicting the IMC layer thicknesses were determined. Using
Arrhenius analysis, the activation energy for intermetallic layer growth was calculated to be approximately 7 kCal/mol. This
value is significantly lower than the value of approximately 24 kCal/mol reported in the literature for Cu6Sn5. Even
considering the presence of Cu3Sn (counted together with Cu 6Sn5) which has about 15 % higher activation energy of
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formation than Cu6Sn5, the experimentally measured values were still lower. The discrepancy was attributed to the fact that
the values reported in the literature were mostly based on solid-state transformations while the measurements and
calculations in this work were limited to the intermetallic layer formation from liquid state followed by growth.
Auteur(s) : MADENI J.C., LIU S., DE ANDRADE P.H.S, CARSON. C.H.
Affiliation(s) : Center for Welding, Joining, and Coatings Research, George Ansell Metallurgical and Materials Engineering Department
Pays : Etats-Unis
Cote ISDOC : WW201503.325-338
Soudobrasage
Effet de l'aluminisation par immersion à chaud sur les caractéristiques mécaniques et la
microstructure à l'interface des assemblages Ti/Al réalisés par soudobrasage TIG
Effect of hot dip aluminising on interfacial microstructure and mechanical properties of Ti/Al joint by TIG arc welding
brazing
The joint of Al 5A06 and aluminised Ti-6Al-4V dissimilar alloys was achieved by means of tungsten inert gas arc welding
brazing. The effect of aluminized coating on the spreading behaviour of filler metal on Ti substrate was studied. The
spreadability of liquid filler metal on the Ti substrate was enhanced obviously due to the presence of aluminised coating. The
interfacial reaction layer was characterised by a uniform lamellar layer of TiAl 3 intermetallic, with a thickness of 1 mm. Sound
joints with well appearance were obtained, and the optimised tensile strength of the joint reached 216 MPa. The failure
initiated from the interfacial layer at the root face and then propagated within the weld seam at the upper part of the joint.
Capable welding parameters were broadened by the presence of aluminised coating for dissimilar metal joining of Ti/Al.
Auteur(s) : WAN L., LV S., HUANG Y., XU Y., CUI Q.
Affiliation(s) : State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Changchun Institute of Optics, Chinese Academy of
Sciences
Pays : Chine
Rechargement
Contrôle de la variable électrode positive/électrode négative lors du rechargement dur sous flux
en polarité variable de carbures de chrome primaires
Primary chromium carbide fraction control with variable polarity SAW
Using alternating current (AC) when welding chromium carbide hardfacing alloys has a pronounced effect on the resulting
welds. To examine exactly the effect of AC balance (fraction of time in electrode positive) on FeCrC hardfacing, six different
samples were made varying from 50 to 75% balance in 5% increments. The heat input was found to increase from 3.82 to
4.30 kJ/mm and dilution along the centerline increased from 3.7 to 31.1%. The ultimate consequence of increasing the
balance was a decrease in the volume fraction of primary carbides from 21 to 3% and a decrease in average diameter of
carbides from 30.3 to 21.8 mm with the increase in balance. The increase in the volume fraction of carbides also coincided
with microstructures that had higher percentages of hypereutectic microstructures that should lead to more uniform wear
throughout the height of the hardfacing. The increase in volume fraction of carbides as the balance decreases should also
increase the wear resistance. The use of AC waveform with balances near 50% gave microstructures expected to perform the
best.
Auteur(s) : BORLE S.D., LE GALL I., MENDEZ P.F.
Affiliation(s) : University of Alberta
Pays : Canada
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Traitements thermiques
Le préchauffage - Mal compris, souvent négligé et parfois mal effectué
Preheat - Misunderstood, often overlooked, and sometimes misapplied
Whether preheat is required or not, and regardless of the method implemented, preheat can provide any combination of the
following benefits: reduce shrinkage stresses in the weld and adjacent base metal, especially in highly restrained joints;
provide a slower rate of cooling through the critical temperature range, preventing excessive hardening and reduced ductility
of both the weld and HAZ; provide a slower rate of cooling through the 400°F (200°C) range, allowing more time for hydrogen
that may be present to diffuse away from the weld and adjacent base metal to avoid hydrogen induced cracking; and remove
contaminants. It is always desirable to achieve a through-thickness soak at the prescribed preheat temperature.
Inappropriate application of local preheat too often can result in damaged material and must be avoided.
Auteur(s) : NEWELL W.F.Jr
Affiliation(s) : Euroweld, Ltd.
Pays : Etats-Unis
Effets d'un TTAS sur la microstructure et les caractéristiques mécaniques d'un métal fondu
ERNiCrFe-7 hors dilution
Effects of PWHT on the microstructure and mechanical properties of ERNiCrFe-7 all-weld metal
The effects on the microstructure and room temperature mechanical properties of the nickel-based filler metal ERNiCrFe-7
due to a post weld heat treatment (PWHT) at 610°C have been studied. It was shown that PWHT caused an increase in yield
strength and ultimate tensile strength, but at the cost of reduced ductility and impact toughness. Crack tip opening
displacement (CTOD) fracture toughness tests revealed an initial increase in maximum CTOD when a short PWHT was given,
but declined with prolonged PWHT. The PWHT also caused a transition in fracture mechanism from microvoid coalescence to
quasi-cleavage in room temperature air. Chromium-rich M23C6 type grain boundary carbides were present already in the aswelded weld metal, and were observed to coarsen during the PWHT. Intragranular M 23C6 carbides were not observed in the
as-welded state, but were precipitated during the 610°C PWHT. Precipitation of these intragranular carbides is believed to be
the main reason for the changes in mechanical properties.
Auteur(s) : SHEN R.R., ZHOU Z., LIU P., CHAI G.
Affiliation(s) : KTH Royal Institute of Technology, Sandvik Materials Technology
Pays : Suède
Cote ISDOC : WW201503.317-323
Traitement thermique après soudage de fontes de fortes épaisseurs
PWHT of thick ferrous castings
To understand postweld heat treatment (PWHT) of steel, you need to know the upper and lower critical temperatures for
steel. Why? Looking at the change of steel crystal structures and its polymorphism at changing temperatures supplies
valuable insight. This article addresses the following areas: making sure the casting and/or weld is at temperature with
respect to thick sections, the importance of time at temperature during different cycles, lag time between oven air
temperatures, the casting’s surface vs. centerline of thick sections, and the need to avoid temper embrittlement.
Auteur(s) : THOMAS E.
Affiliation(s) : Bradken Tacoma, Tacoma, Washington
Pays : Etats-Unis
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Coupage
Sélectionner un équipement de coupage plasma
Selecting a plasma arc cutting system
Selecting a new plasma arc cutting (PAC) system is a lot like selecting a new truck. Plasma systems, like trucks, range from
light duty, personal use models to heavy-duty industrial models, with specialized versions available to meet specific customer
needs. All share certain attributes, but within each class there are other features that are unique to the specific model. In the
end, what really matters is which one meets the customer’s needs most efficiently and most cost effectively. There are no
industry standards for comparing PAC systems, so customers are left with confusing and contradicting information from the
manufacturers. Historically, cutting capacity and initial purchase cost have been the key considerations for selecting a
system. While capacity and price contribute to the decision-making process, additional factors should also be considered. The
operating cost - the actual cost of ownership - should be the most important cost consideration. There are often significant
differences in operating cost among various systems, and in a year of cutting these differences can really add up. This article
presents a set of questions as a guide for selecting the best system for your needs, a list of some attributes that all PAC
systems share with an explanation of why each is important, and an easy to use method for calculating operating cost.
Affiliation(s) : Hypertherm Hanover, N.H.
Pays : Etats-Unis
Ventilation des tables automatisées pour la découpe des métaux
Ventilation of automated metal cutting tables
This study investigated the specific airflow dynamic properties of capture systems fitted to automated metal cutting tables.
Tests were conducted on a multi-zone ventilated table equipped with suction slots incorporated into the side panels of the
dross box. They led to a better understanding of the detailed flow structure near the table and, in particular, characterized
the airflows through the various passages between the compartment under suction and the rest of the workshop; these
airflows counteract potential pollutant leaks. The impacts of the following operating parameters on the distribution of air
velocities induced by the ventilation were studied: dimensions and position of the plate to be cut on the supporting table; air
extracted through slots on one or two sides; position of cutting point with respect to table length; presence of peripheral
protective screens; and the existence of drafts in the workshop.
Auteur(s) : BRACONNIER R.
Affiliation(s) : Institut National de Recherche et de Sécurité, Vandoeuvre lès Nancy
Pays : France
Collage
Influence du processus de durcissement sur la résistance d'assemblages collés à l'aide d'adhésifs
durcissant à chaud
Influence of the curing process on joint strength of a toughened heat-curing adhesive
Lightweight construction methods will make a significant contribution to sustainable CO2 reduction in new car body
developments. Multi-material design offers cost-efficient lightweight solutions for car mass production. The key to
successfully drive this development trend is a particularly economical, safe and sustainable joining technique: adhesive
bonding. In automotive production, the car body must be heated in an oven to ensure the curing process of the adhesives.
The increase in temperature leads to different expansion performance of adherends according to their individual thermal
expansion behaviour. Stresses occurring may be so great as to cause plastic deformation in the joint area. During cooling of
the bonded construction, further relative displacements occur between the joint partners, which can lead to joint failure.
These effects influence the usability, sustainability and long-term durability of adhesively bonded components and have not
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yet been considered for use in automotive car body design. As part of a research project, a test stand was built to allow
adhesive bonds to be cured under diverse selected temperature-time profiles e.g. to simulate the cathodic dip-paint process.
Various degrees of adhesive curing can be realized and the influence on the joint evaluated in a subsequent tensile test.
Parameters such as the maximum strength or displacement at fracture, but also the plastic deformation behaviour of the
used toughened adhesive system, depend on the degree of curing. Temperature related relative displacements are simulated
by applying an additional mechanical stress during adhesive curing. Their influence on the mechanical properties of the
adhesive bond is evaluated in a subsequent tensile test. There is a significant influence of relative displacement on the
mechanical behaviour of the adhesive joint during adhesive curing.
Auteur(s) : MESCHUT G., HAHN O., TEUTENBERG D.
Affiliation(s) : University of Paderborn
Pays : Allemagne
Cote ISDOC : WW201502.209-216
Mécanismes de frittage et caractéristiques mécaniques d'assemblages collés réalisés à l'aide de
nanoparticules d'argent et destinés à des applications électroniques
Sintering mechanisms and mechanical properties of joints bonded using silver nanoparticles for electronic packaging
applications
The low-temperature bonding process using metal nanoparticles has attracted considerable attention due to its potential
applications including electronic packaging. However, the fundamental understanding of this advanced bonding technology is
still limited. In this study, Ag nanoparticle paste used as a bonding material is prepared by the chemical reduction method.
The sintering behaviors of Ag nanoparticles during the bonding process were investigated using the classical sphere-tosphere approach. At low sintering temperatures (160-250°C), the calculated mechanism-characteristic exponent n is 7.9,
which indicates that surface diffusion is the dominant diffusion mechanism. With the increase of temperatures (300-350°C),
mechanism characteristic exponent n changes to 3.75. This indicates that volume diffusion is probably the prevailing
diffusion mechanism at this stage. Based on the classical sphere-to-sphere model, the relationship between the joint strength
evolution and neck growth of Ag particles is revealed. It is found that the joint strength is proportional to square of neck size
ratio (x/r)2 of sintered Ag particles.
Auteur(s) : YAN J., ZOU G., LIU L., ZHANG D., BAI H., WU A.P., ZHOU Y.N.
Affiliation(s) : Tsinghua University, National Engineering and Technological Research Center for Non ferrous Metal Composites, General Research
Institute for Nonferrous Metals, Centre of Advanced Materials for Joining, Department of Mechanical and Mechatronics Engineering, University of
Waterloo
Pays : Chine, Canada
Cote ISDOC : WW201503.427-432
Plastiques
Etude sur le soudage par vibration linéaire du nylon type 66 renforcé de fibre de verre - Lauréat
du prix Henry Granjon 2014 catégorie A : technologies d'assemblage et de fabrication
Research into linear vibration welding of glass fibre-reinforced nylon 66 - Henry Granjon Prize 2014 - Winner Category A Joining and Fabrication Technology
In this paper, results of vibration welding of glass fibre-reinforced nylon 66 are presented. The hot air blower was used for
preheating of the welded surfaces before the welding process. The aim of the research was determination of the influence of
the thermal conditions of vibration welding process on the quality of joints, including weld microstructure, the content of the
crystal phase, orientation of the glass fibres in the weld and the tensile strength. Influence of the welding conditions on the
weld microstructure and the orientation of the glass fibres is determined during the light microscopic examinations as well as
in the scanning electron microscopic examinations. A melting temperature and the content of the crystal phase of welds
were tested using differential scanning calorimetry (DSC). Fitting of the mathematical function describing penetration curve
was performed, and calculations of the heat power were made. Comparison of results of vibration welding of nylon
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composite conducted with and without preheating was carried out. Results indicate that the use of preheating during
vibration welding process eliminates the solid-state friction in the welding process and leads to the significant improvement
of the welds quality at the shorter weld time.
Auteur(s) : WEGLOWSKA A.
Affiliation(s) : Instytut Spawalnictwa (Institute of Welding)
Pays : Pologne
Cote ISDOC : WW201503.339-352
Dégradation thermique du polycarbonate et du polyamide 6 en soudage laser par transmission
Thermal degradation of PC and PA6 during laser transmission welding
Laser transmission welding (LTW) causes a temperature rise at the weld interface which leads to melting, molecular diffusion
and ultimately joining of the two components. Weld temperatures increase with laser power at a given scan speed. However,
at higher temperatures, it has been observed that weld strength starts to decline due to material thermal degradation.
Thermal degradation is a kinetic phenomenon which depends on both temperature and time. Thermal gravimetric analysis
(TGA) is used to study the thermal degradation of two commonly used thermoplastic materials: polycarbonate (PC) and
polyamide 6 (PA6). Each material was studied at several levels of carbon black (CB). The TGA data were then used to obtain
the kinetic triplets (frequency factor, activation energy and reaction model) of the materials using a non-linear model-fitting
method. These kinetic triplets were combined with temperature-time data obtained from a finite element method (FEM)
simulation of the LTW process to predict material degradation. The conditions predicted to cause thermal degradation were
then compared with experimental data. It is found that the predicted onset of material degradation is in reasonable
agreement with both the onset of experimentally observed degradation and the onset of weld strength decline for PC and
PA6.
Auteur(s) : BATES P.J., OKORO T.B., CHEN M.
Affiliation(s) : Royal Military College of Canada
Pays : Canada
Cote ISDOC : WW201503.381-390
Matériaux dissemblables
Etude expérimentale et modélisation de couches fondues dans des structures mixtes
polymère/métal
Experimental investigations and modeling of the melting layer in polymer-metal hybrid structures
The melting layer in thermal joining of polymer-metal hybrid joints is analyzed according to process management and
microstructure. These results were transferred to spot joints for describing the material behavior and the resulting joining
zone. This leads to a generally valid model concept for laser-based polymer-metal joining.
Auteur(s) : SCHRICKER K., STAMBKE M., BERGMANN J.P.
Affiliation(s) : Department of Production Technology, TU Ilmenau
Pays : Allemagne
Cote ISDOC : WW201503.407-412
Caractéristiques méaniques d'assemblages dissemblables constitués d'acier DP 980 et d'alliage
d'aluminium 7075-T6
Mechanical properties of dissimilar metal joints composed of DP 980 steel and AA 7075-T6
A solid state joining process, called friction bit joining, was used to spot weld aluminium alloy 7075-T6 to dual phase 980
steel. Lap shear failure loads for specimens without adhesive averaged approx. 10 kN, while cross-tension specimens
averaged 2.8 kN. Addition of adhesive with a thickness up to 500 mm provided a gain of approx. 50% to lap shear failure
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loads, while a much thinner layer of adhesive increased cross-tension failure loads by 20%. Microstructures of the welds were
martensitic, but the hardness of the joining bit portion was greater than that of the DP 980, owing to its higher alloy content.
Softening in the heat affected zone of a welded joint appeared to be relatively small, though it was enough to cause nugget
pullout failures in some lap shear tension specimens. Other failures in lap shear tension were interfacial, while all of the
failures in cross-tension were interfacial.
Auteur(s) : SQUIRES L., LIM Y.C., MILES M.P., FENG Z.
Affiliation(s) : Manufacturing Engineering Technology, Brigham Young University, Materials Science & Technology Division, Oak Ridge National
Laboratory
Pays : Etats-Unis
Effet d'un traitement électrolytique au plasma pour l'assemblage des métaux aux plastiques
Effect of plasma electrolytic oxidation coating on joining metal to plastic
Joining of magnesium alloy to polyethylene without adhesive using a newly developed friction lap welding technology was
investigated. The polyethylene and magnesium alloy were hard to be joined together without surface pre-modification due
to the lack of polar groups on polyethylene surfaces. Strong hybrid joints were achieved after the polyethylene was treated
by corona discharge, and the magnesium alloy was subjected to plasma electrolytic oxidation treatment. Scanning electron
microscope and high resolution transmission electron microscope observations demonstrated that the high joining strength
was attributed to the development of both chemical bonds at the interface and micromechanical interlocking.
Auteur(s) : LIU F.C., LIAO J., GAO Y., NAKATA K.
Affiliation(s) : JWRI, Osaka University, Kurimoto Ltd
Pays : Japon
Métallurgie du soudage
Evolution de l'hydrogène dans la ZAT d'un acier à précipitation de cuivre de grade 780 MPa au
regard de sa susceptibilité à la fissuration à froid
Hydrogen evolution of Cu precipitation 780 MPa grade steel HAZ with consideration of its cold cracking susceptibility
The Cu precipitation 780 MPa grade steel has higher resistance to cold cracking than the conventional steels. To study this,
we have investigated the hydrogen evolution characteristics of the Cu steel heat-affected zone (HAZ) by the thermal
desorption spectroscopy method and compared with those of conventional 780 MPa steel HAZ. The thermal cycle tests were
conducted to obtain the HAZ microstructures, and the peak temperatures were selected from 500 to 1400° C at intervals of
100°C. Hydrogen was then charged, and the hydrogen evolution curves were measured at a heating rate of 100°C/h. The
results show that the amounts of hydrogen released from the specimens whose peak temperatures of the thermal cycle tests
were 1000°C or higher are lower, while the results of the conventional steels have the opposite tendency. We numerically
calculated the hydrogen evolution curves to determine physical constants, and using these constants, we also calculated the
hydrogen concentration profiles of the y-groove weld cracking test and found that the hydrogen concentration of the Cu
steel HAZ near the fusion line tends to become lower than those of the conventional steel HAZ. This phenomenon is
considered one of the reasons for the higher cold cracking resistance of the Cu steel.
Auteur(s) : KASUYA T., IZAWA T., KAKESHITA T., KUMAGAI T., WATANABE K.
Affiliation(s) : Nippon Steel & Sumitomo Metal Corporation, Osaka University
Pays : Japon
Cote ISDOC : WW201503.353-364
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Formation de zone appauvries en manganèse dans les zones fondues contenant du titane
Formation of Mn-depleted zone in Ti-containing weld metals
Characteristics of non-metallic inclusions are studied using three shielded metal arc (SMA) weld metals which differ greatly in
Ti content and are correlated with the acicular ferrite contents measured in the as-deposited weld microstructure.
Correlation is found between the inclusion phases present and the amount of acicular ferrite formed in each weld. In the 5
ppm Ti weld, the weld microstructure is extremely low in acicular ferrite content and this microstructure can be correlated
with the amorphous Mn-silicate phase that formed abundantly in the inclusions of this weld. At 410 and 580 ppm Ti, the
weld microstructure contains very high amount of acicular ferrite, and this microstructure can be explained by the presence
of a Mn-depleted zone (MDZ), likely formed associating with the formation of inclusions dominant with Ti2O3 and MnTiO3.
The possible mechanisms for MDZ formation are discussed.
Auteur(s) : SEO K., KIM Y.M., EVANS G.M., JIN K.H., LEE C.
Affiliation(s) : Hanyang University, Korea Institute of Industrial Technology
Pays : Corée
Cote ISDOC : WW201503.373-380
Observation in situ de la formation de ferrite aciculaire et de l'affinage des grains dans la zone
affectée thermiquement simulée d'un acier à haute résistance faiblement allié
In situ observation of acicular ferrite formation and grain refinement in simulated heat affected zone of high strength low
alloy steel
The phase transformation from austenite to acicular ferrite in the simulated coarse grained heat affected zone of a high
strength low alloy steel was investigated by means of analytical characterisation techniques such as in situ microscopy,
transmission electron microscopy and electron backscattered diffraction analysis. The acicular ferrite grains nucleated on
inclusions (Zr-Ti oxides) in coarse austenite grain grew in different directions and effectively partitioned coarse austenite
grain into several finer and separate regions. The crystallographic grain size became small for coarse austenite grains due to
the effective partitioning by acicular ferrite laths or plates.
Auteur(s) : WAN X.L., WU K.M., NUNE K.C., LI Y., CHENG L.
Affiliation(s) : The State Key Laboratory of Refractories and Metallurgy, Hubei Collaborative Innovation Center for Advanced Steels, International
Research Institute for Steel Technology, Wuhan University of Science and Technology, Department of Metallurgical and Materials Engineering, University
of Texas at El Paso
Pays : Chine, Etats-Unis
Mode de solidification du métal fondu d'un alliage de base nickel à forte teneur en chrome
Solidification behaviour of a high chromium nickel base alloy weld deposited metal
The solidification behaviour including micro-segregation and secondary phase formation of a high chromium nickel base alloy
weld deposited metal was examined with optical microscopy, scanning electron microscopy and transmission electron
microscopy. Micro-segregation potential of major alloying elements in the weld deposited metal was investigated. The microconstituents formed during solidification were identified to be TiC and γ/Laves eutectic constituent. Most γ/Laves eutectic
constituents were located at the dendrite interstices due to the micro-segregation of Nb, Mo and Si. The volume percent of
γ/Laves constituent was predicted by using Scheil equation, and there was a reasonable agreement between the predicted
and measured value. Last, two possible solidification paths added to the γ-Nb-C pseudo-ternary solidification diagram were
proposed to analyse the solidification sequence of the new high chromium nickel base alloy.
Auteur(s) : DI X.J., CHEN B.
Affiliation(s) : Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, School of Materials Science and Engineering, Tianjin University
Pays : Chine
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Effet des variantes de transformations cristallographiques en zone fondue de soudures réalisées
sous protection gazeuse avec fil-électrode fusible
Effect of variant transformations in fusion zones of gas metal arc welds
The macro- and microtextures of gas metal arc welds fabricated using both conventional ferritic and low transformation
temperature (LTT) filler metals were examined. Both welds were largely composed of acicular ferrite. The weld textures were
found to be distinct, which is observed to be due to variant selection during the austenite to ferrite transformation. In situ
electron backscatter diffraction performed during thermal cycling of the LTT fusion zone into the austenite phase field
confirmed that these transformations satisfy the expected crystallographic relationships. Implications for welding
consumable design and finite element process modelling are drawn.
Auteur(s) : BERES M., ABREU H.F.G., SANTOS L.P.M., DAVIES C.M., DYE D.
Affiliation(s) : Universidade Federal Do Ceara
Pays : Brésil
Influence de l'azote sur la microstructure et les caractéristiques mécaniques des alliages de nickel
Nitrogen effect on the microstructure and mechanical properties of nickel alloys
In this research, the effects of nitrogen addition in Ar gas on weld metal microstructure and mechanical properties of Alloy
263 (UNS N07263) and Alloy X (UNS N06002) were studied. Autogenous gas tungsten arc welding (GTAW) was employed by
adding 0-4 vol% N2 in Ar. Welding speed and heat input rate were measured as functions of gas composition. The weld metal
microstructure was studied by optical and scanning electron microscopy. Experimental results demonstrated that the
dendritic structure of the weld was refined by increasing N 2 in Ar for both alloys. An addition of 4 vol% N 2 to Ar decreased
significantly the columnar region in Alloy 263 fusion zone (FZ), while no similar change was observed in Alloy X. This
difference is discussed based on microstructural characterization. Finally, it was found that the tensile strength and hardness
have been augmented with increased nitrogen in the shielding gas.
Auteur(s) : NABAVI B., GOODARZI M., AMANI V.
Affiliation(s) : School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran, School of Metallurgical and Materials
Engineering, College of Engineering, University of Tehran
Pays : Iran
Fatigue
Assurance qualité du traitement de martelage à haute fréquence des soudures à l'aide d'un
système de balayage laser 3D manuel
Quality assurance for high-frequency mechanical impact (HFMI) treatment of welds using handheld 3D laser scanning
technology
The idea of using 3D point clouds obtained with the aid of a handheld 3D laser scanner for the quality assurance of highfrequency mechanical impact (HFMI) treatment is proposed and demonstrated in this paper. The effectiveness of impact
treatments for extending the fatigue lives of welded structures has been demonstrated in numerous studies. Guidelines for
the proper execution of impact treatments have been developed. A lack of suitable quality assurance (QA) procedures for
accepting or rejecting the treatment after completion has been previously identified. In contrast with the existing QA
procedures, which are based mainly on controlling inputs and visual inspection, a technology-based, quantitative
methodology is developed in this paper. Five welded specimens were subjected to impact treatment at various levels to
simulate under-, proper, and over-treatment. A handheld 3D laser scanner was then used to facilitate a point cloud-based
method to determine the geometric parameters of the treated weld toe groove, which were then measured manually. The
results show that the proposed methodology is successful in identifying the different treatment levels. This approach has a
number of advantages over the existing QA methods, including the following: providing quantitative measures, ease of use,
and archive-ability.
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Auteur(s) : GHAHREMANI K., SAFA M., YEUNG J., WALBRIDGE S., HAAS C., DUBOIS S.
Affiliation(s) : Department of Civil and Environmental Engineering, University of Waterloo, Creaform Inc.
Pays : Canada
Cote ISDOC : WW201503.391-400
Une nouvelle méthode pour les essais de fatigue-corrosion appliqués au placage des tubes d'eau
A new method for corrosion fatigue testing of weld cladding waterwall coatings
The use of low nitrogen oxide (NOx) boilers in coal fired power plants has resulted in corrosive combustion conditions that
have led to a reduction in the service lifetime of water-wall tubes. As a solution, Ni-based weld claddings are being used to
provide the necessary corrosion resistance. However, they are often susceptible to premature failure due to corrosion
fatigue cracking. In order to mitigate the cracking problem, significant research efforts are needed to develop a fundamental
understanding of the corrosion fatigue behavior of Ni-based claddings. In this work, an experimental method was developed
to characterize the corrosion fatigue behavior of weld claddings. A Gleeble thermo-mechanical simulator was adapted to
permit the exposure of samples to a simulated corrosive combustion gas at a constant elevated temperature while applying a
controlled cyclic stress. The results demonstrate that this experimental method can be used to accurately simulate the
corrosion fatigue mechanism of weld claddings that has been observed in service. The implementation of this experimental
method will allow for a better understanding of the corrosion fatigue behavior of water-wall claddings in combustion
environments and provide a tool for optimizing the corrosion fatigue resistance.
Auteur(s) : STOCKDALE W., DUPONT J.N., HARLOW D.G.
Affiliation(s) : Department of Materials Science and Engineering, and Department of Mechanical Engineering and Mechanics, Lehigh University,
Bethlehem
Pays : Etats-Unis
Fluage
Corrélation entre formation de ferrite et tenue au fluage des soudures sur acier Cr-Mo - Lauréat
du prix Henry Granjon 2013 catégorie B : comportement des matériaux et soudabilité
Correlation of ferrite formation to creep properties of Cr-Mo steel welds - Henry Granjon prize 2013 winner category B:
materials behaviour and weldability
-4
-4
A factor of four decreases from 16.0×10 to 4.1×10 %/h in steady state creep rate was observed in the fine grained heataffected zone (FGHAZ) of a Cr-Mo steel weld, by reducing the pre-weld tempering temperature from 760 to 650°C. The
current study used electron backscatter diffraction and synchrotron x-ray diffraction techniques to characterize the
microstructure in the FGHAZ of the two tempering temperature conditions. The results showed carbide-free ferrite that
formed in the FGHAZ of weldments that were pre-weld tempered at 760°C, contributed to void formation resulting in lower
creep strength. It is proposed that the formation of ferrite in the FGHAZ is due to the incomplete dissolution of Cr23C6 carbide
at heating process during welding, which results in Cr enrichment adjacent to the undissolved Cr 23C6 carbide. Dictra
simulation confirmed ferrite formation at the carbide/austenite boundaries during Cr 23C6 carbide dissolution.
Auteur(s) : XINGHUA YU
Affiliation(s) : Oak Ridge National Laboratory
Pays : Etats-Unis
Cote ISDOC : WW201502.251-259
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Contraintes, déformations et retrait
Effets de la transformation de la phase austénitique sur les contraintes résiduelles de soudures
longitudinales ne supportant pas de charges
On the effects of austenite phase transformation on welding residual stresses in non-load carrying longitudinal welds
Residual stresses affect the fatigue strength of welded structures and components. A common sample type used for studies
on residual stress effects is the fillet-welded longitudinal gusset. This sample type shows in fatigue tests significant residual
stress effects. But the mechanisms of residual stress generation are not clarified for this sample type yet. High tensile residual
stresses in the surface layer near the weld toe could not be proven by experimental methods but are generally assumed.
Here presented are results from experimental and numerical investigations on welding residual stress generation. Specimens
with single and multilayer fillet welds have been produced as well as simplified curved multilayer deposition welds studying
residual stress build-up. Temperature measurements have been conducted during welding examining the influence of
austenite phase transformation. Residual stresses have been determined by means of X-ray diffraction at the surface as well
as by neutron diffraction over specimen thickness. Further, the mechanisms of residual stress build-up have been evaluated
by finite element calculations. It could be shown that the austenite phase transformation has significant effect on the
residual stresses near the weld toe also for this sample type.
Auteur(s) : HENSEL J., NITSCHKE-PAGEL T., DILGER K.
Affiliation(s) : Institute of Joining and Welding, Technische Universität Braunschweig
Pays : Allemagne
Cote ISDOC : WW201502.179-190
Analyse numérique de l'effet des hétérogénéités de résistance mécanique sur le champ de
contraintes d'éprouvettes Charpy
Numerical analysis of strength mismatch effect on stress field in Charpy specimen
The influence of strength mismatch adjacent to the V-notch in Charpy specimen on stress field has been numerically analyzed
with a 3D finite element method. It is found that the softer material adjacent to the V-notch provides a “shielding effect”
from high-speed straining introduced by impact loading. As this leads to reduction in flow stress ahead of the V-notch, lower
opening stress compared with homogeneous specimen is found in the case of the V-notch within the harder material in
heterogeneous specimen. By contrast, in the case of the V-notch within the softer material, plastic strain is concentrated
near the V-notch and the opening stress is elevated by constraint due to hard material adjacent to the V notch. The Charpy
impact test was conducted with the Charpy specimen extracted from the clad steel consisted of low- and high-strength steels
in order to investigate the strength mismatch effect Charpy absorbed energy KV. It is found that KV value is affected by
strength mismatch adjacent to the V-notch and the Weibull stress criterion can be applied to the quantitative evaluation of
the strength mismatch effect on KV.
Auteur(s) : TAKASHIMA Y., YAMADA Y.S., HANDA T., IGI S., OI K., MINAMI F.
Affiliation(s) : Osaka University, JFE Steel Corporation
Pays : Japon
Cote ISDOC : WW201503.433-441
Mesure in situ et modélisation des déformations et de la température lors du soudage à l'arc
In situ strain and temperature measurement and modelling during arc welding
Experiments and numerical models were applied to investigate the thermal and mechanical behaviours of materials adjacent
to the weld pool during arc welding. In the experiment, a new high temperature strain measurement technique based on
digital image correlation (DIC) was developed and applied to measure the in situ strain evolution. In contrast to the
conventional DIC method that is vulnerable to the high temperature and intense arc light involved in fusion welding
processes, the new technique utilised a special surface preparation method to produce high temperature sustaining speckle
patterns required by the DIC algorithm as well as a unique optical illumination and filtering system to suppress the influence
of the intense arc light. These efforts made it possible for the first time to measure in situ the strain field 1 mm away from
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the fusion line. The temperature evolution in the weld and the adjacent regions was simultaneously monitored by an infrared
camera. Additionally, a thermal-mechanical finite element model was applied to substantiate the experimental
measurement.
Auteur(s) : CHEN J., YU X., MILLER R.G., FENG Z.
Affiliation(s) : Oak Ridge National Laboratory
Pays : Etats-Unis
Profil des contraintes résiduelles dans les assemblages de tôles fines d'acier réalisés par rivetage
Residual stress profiles in riveted joints of steel sheets
The residual stress profiles in two different self-piercing riveted (SPR) joints were characterised using the neutron diffraction
technique. The joints were produced using semi-tubular steel rivets and carbon steel sheets of different thicknesses and
hardnesses. The residual stress in the sheet material inside the bore of the rivet was compressive at the centre and the stress
became tensile away from the centre. The stresses found in the semi-tubular rivet were compressive, with a lower
magnitude in the rivet head compared with those in the rivet leg. For the SPR joints examined, the compressive residual
stress in the rivet leg was greater for the thin joint than the thick joint, and this was due to the higher force gradient
encountered during the rivet flaring stage. The originality of this work was to relate the residual stress profile to the physical
event that occurred during the SPR process.
Auteur(s) : HAQUE R., WONG Y.C., PARADOWSKA A., DURANDET Y.
Affiliation(s) : Faculty of Science, Engineering and Technology, Swinburne University of Technology, Australian Nuclear Science and Technology
Organisation
Pays : Australie
Influences des caractéristiques mécaniques du métal fondu et de la température de
transformation de phase sur les contraintes résiduelles de soudage
Effects of weld metal strength and transformation temperature on welding residual stress
In this study, we assess the effects of weld metal strength and transformation temperature on the residual stress in 2.25Cr1.6 W steel welded joints. We find that the stress levels in the weld and the peak residual stress position in the base metal
can be controlled by the appropriate selection of filler metal. Low transformation temperature weld metals are capable of
inducing compressive residual stresses in the weld bead. Meanwhile, for stresses and bending moment equilibrium, the high
strength weld metal pushes the peak tensile stress outward to reside at the base metal, keeping off the weak region. A
reasonable agreement is obtained between the numerical modelling considering phase transformation and the accurate local
stresses measurement associated to weld microstructure regions.
Auteur(s) : XU M., CHEN J., JIN Y., LI Y., LU H.
Affiliation(s) : School of Materials Science and Engineering, Shanghai Jiao Tong University
Pays : Chine
Conception et calcul
Optimisation de viroles tronconiques soudées soumises à compression axiale et charges de flexion
Optimization of welded conical shells for axial compression and bending
The problem is to find the optimum dimensions of a cantilever column loaded by compression and bending. The column is
constructed as a circular or conical unstiffened shell. In both cases, the cost minimum is not limited by a fabrication
constraint, by which the minimum shell radius would be prescribed. The cost comparison of both structural versions shows
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the most economic one.
Auteur(s) : JARMAI K., FARKAS J.
Affiliation(s) : University of Miskolc
Pays : Hongrie
Cote ISDOC : WW201503.401-406
Longueur efficace des soudures pour les assemblages en T de sections creuses rectangulaires
soumis à des charges de flexion - Lauréat du prix Henry Granjon 2014 catégorie C : conception et
intégrité structurale
Weld effective lengths of rectangular hollow section T-connections under branch bending - Henry Granjon prize 2014
winner Category C: Design and Structural Integrity
The 2010 AISC Specification for Structural Steel Buildings has expanded the scope in chapter K: design of HSS and box
member connections to include a section K4: welds of plates and branches to rectangular HSS. An experimental program was
undertaken at the University of Toronto to test various unreinforced RHS-to-RHS 90° T-connections subject to branch inplane bending moment with the objective of determining the effectiveness of the welded joint. Twelve unique test
specimens were designed to be weld-critical, and the results from the full-scale tests revealed that the current equation for
the effective elastic section modulus for in-plane bending, Sip, given in Table K4.1 of AISC 360-10 is very conservative. A
modification to the current requirements that limits the effective width of the transverse weld elements is proposed,
resulting in a safe and more economical weld design method for RHS-to-RHS T-, Y- and X- connections subject to branch axial
1.5
load or bending moment. It is also concluded that the fillet weld directional strength enhancement factor, (1.00+0.50sin θ),
should not be universally applied to all connections between square and rectangular hollow structural sections in
combination with effective weld properties as it may result in an unsafe design.
Auteur(s) : MC FADDEN M.R.
Affiliation(s) : MMM Group
Pays : Canada
Cote ISDOC : WW201502.295-305
Contrôles non destructifs
Une méthode à ondelette innovante pour la surveillance par vibration de roulements à bille
Novel wavelet technology for vibration condition monitoring of rolling element bearings
In this paper, a novel wavelet technology is proposed and experimentally validated for bearing diagnosis. The methodology
differs from the past literature in terms of calculating the wavelet transform for successive realisations (referred to as periods
in this paper) of the whole signal. The novel wavelet technology proposed here for bearing diagnosis is adaptive to the
stochastic nature of the bearing signal and, thus, remains insensitive to the ball/roller slippage in the bearing raceways. A
diagnostic feature in the form of a normalised instantaneous integrated wavelet modulus has been employed for bearing
condition monitoring. By using experiment data, the novel wavelet technology is validated and the diagnostics potential is
revealed. It has been shown that the proposed technology has an advantage over the classical envelope spectra due to the
fact that the proposed technology requires a smaller signal length in comparison with the enveloping/demodulation
technique.
Auteur(s) : GELMAN L., MURRAY B., PATEL T.H., THOMSON A.
Affiliation(s) : Cranfield University, Cranfield, SKF, Livingston
Pays : Royaume-Uni
Source : Insight, vol.57, n°1, 2015, pp. 40-47 (8 pages) , en anglais
Cote ISDOC : INSIGHT201501.40-47
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Une méthode CND micro-magnétique pour l'évaluation des délaminages dans les plastiques
renforcés de fibres de carbone
Micro-magnetic NDT for delamination defects in carbon fibre-reinforced plastic
This study proposes a micro-magnetic non-destructive testing (NDT) method in the geomagnetic field to detect delamination
defects in carbon fibre-reinforced plastic (CFRP). The relative permeability of the CFRP is slightly greater than that of air, as
determined by CFRP material magnetisation. Thus, CFRP is a weak paramagnetic substance. The mechanism of the micromagnetic NDT method is analysed based on the CFRP delamination defect’s magnetic anomaly characteristics. Furthermore,
a defect determination criterion is used to investigate three artificial delamination defects preset in a specimen. The
amplitudes of magnetic induction intensity changing between 25 and 50 nT are considered as a magnetic anomaly caused by
the defects. Moreover, the areas are consistent with the preset position of the artificial defects. The signal differential
treatment can assist the preliminary quantification. A new method is provided to quickly and effectively detect delamination
defects in CFRP. In addition, new ideas for defect detection are suggested.
Auteur(s) : BO H., RUNQIAO Y.
Affiliation(s) : Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hang Kong University, Nanchang
Pays : Chine
Analyses théoriques d'une méthode de contrôle par flux de fuite d'un courant électrique alternatif
et vérification expérimentale
Theoretical analyses of an alternating current electric flux leakage inspection method and experimental verification
This work proposes an alternating current electric flux leakage (AC-EFL) testing methodology that can be applied to detect
metallic material surface defects. The inspection principles and feasibility of this strategy are described in detail on the basis
of electric field (E-field) theory. Theoretical analyses using a three-dimensional (3D) finite element method (FEM) are
presented to explain the working principle of this technology. A disturbed E-field caused by defects can be decomposed into
a non-conservative (or rotational) E-field that arises from a time-variant magnetic field and a conservative (or irrotational) Efield that results from free charge. 3D FEM simulations were employed to separately analyse the rotational and irrotational Efield distribution inside and outside an AC-carrying aluminium rod with a surface crack. The simulation results demonstrated
that, for metallic materials with high conductivity, the conservative E-field due to free charge could be neglected when the
frequency of the exciting voltage is high compared to the non-conservative E-field produced by the time-varying magnetic
field. Experiments applying a prototype coplanar capacitive probe were also conducted and the experimental results agreed
well with those of the theoretical analyses, confirming the signal mechanisms of AC-EFL.
Auteur(s) : YE Z., KANG Y., SUN Y., YANG G., FENG B.O., ZHOU Q.
Affiliation(s) : School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, The Institute of Agricultural
Machinery, Hubei University of Technology
Pays : Chine
Identification de défauts internes et externes sur pipelines à l'aide de la méthode PSO-SVM
Internal and external defect identification of pipelines using the PSO-SVM method
Defects due to corrosion can occur on both the internal and external surfaces of a pipeline. Magnetic flux leakage (MFL)
pipeline inspection gauges can detect and locate defects on both the internal and external wall surfaces of pipelines but are
generally unable to discriminate between internal and external defects. Therefore, this paper presents a classification
approach to achieve defect discrimination based on support vector machines (SVM). First, time-frequency analysis is
employed to acquire the feature vectors of the time domain and frequency domain from the MFL signal. Then, a distance
evaluation technique is used to remove the redundant and irrelevant information and select the salient features for the
classification process. Next, the selected feature vectors are used as the inputs to the proposed SVM model of defect
classification. The parameters of this model are optimised using the particle swarm optimisation (PSO) algorithm. Finally,
with the optimised model parameters and training sample data, the classification model of the location of the defect based
on SVM is established. The experimental results indicate that the proposed method is an effective approach for internal and
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external defect classification based on the MFL signal.
Auteur(s) : JIAN Q., AI Z.
Affiliation(s) : School of Mechatronic Engineering, Southwest Petroleum University, Chengdu
Pays : Chine
Détection de défauts typiques dans les câbles en acier au moyen d'une analyse en ondelettes
Detecting typical defects in wire ropes through wavelet analysis
Wavelet-based diagnosis of typical defects in wire ropes is investigated in this paper. Due to the characteristics of the
material and structure of steel wire ropes, the magnetic flux leakage (MFL) method is used to detect the typical defects.
Three representative samples with varying extents and types of damage (including broken wires, wear and corrosion) are
fabricated for detection. A characteristic index system, which contains the initial wave, wave width, crest value, trough value
and peak-to-peak value, is put forward to diagnose the defect types in steel wire ropes. The fault signal is decomposed and
reconstructed using wavelet transform to eliminate background noise and to detect singularity. Defect positions are located
by setting a threshold value for the modulus maxima that are extracted from the reconstructed signal. Moreover, wavelet
packet energy analysis is performed to determine the energy distribution of the fault signal. The extent of damage is
estimated by calculating the energy change in the fault frequency band. The results show that the types of defect are
identified effectively via the characteristic index system established in this paper. The locations of defects are obtained
accurately by dint of wavelet transform. Meanwhile, the energy of the fault frequency band is concentrated in the lowfrequency region and increases as the extent of the defect deepens.
Auteur(s) : GAO G., QIN Y., LIAN M., LIU Y.
Affiliation(s) : Beijing University of Technology - Mechanical Engineering and Applied Electronics Technology
Pays : Chine
Avancées en matière de probabilité de détection au travers d'études de modélisation et de
simulation
Developments in probability of detection modeling and simulation studies
There have been considerable contributions to POD modeling in the last decade. It is hoped that procedures for threeparameter and four-parameter models and also the bootstrapping approach for confidence intervals will be codified for
more general use. Simulation studies were introduced as a way of to quantify the effect of sample size on confidence bound
calculations. In the future, such simulation studies can be used to quantify the effect of changes in model form or different
techniques for calculating confidence bounds. Further simulation studies can investigate the effect of the choice of left
censoring that data and the detection threshold on the coverage of the true a90. Hence, it is recommended that future POD
software projects enable simulation studies to facilitate such investigations.
Auteur(s) : KNOPP J.S., CIARALLO F., GRANDHI R.V.
Affiliation(s) : Air Force Research Laboratory (AFRL/RXCA), Ohio, Wright State University, Dayton, Ohio
Pays : Etats-Unis
Source : Materials Evaluation, vol.73, n°1, 2015, pp. 55-61 (7 pages) , en anglais
Cote ISDOC : ME201501.55-61
Quantile de probabilité de détection : distinction entre incertitude et variabilité en contrôle nondestructif
Quantile probability of detection: distinguishing between uncertainty and variability in nondestructive testing
Measurement outputs from a nondestructive testing (NDT) inspection system usually involve different sources of variability
such as operator variation, probe or transducer variation, flaw morphology variation, setup and calibration variation,
environmental related variations, and measurement error. If an appropriate experiment is conducted, it is possible to
estimate the separate effects of different sources of variability. These sources of variability imply that the probability of
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detection (POD) itself is random, depending, for example, on the operator and transducer assigned to do the inspection. The
commonly-used traditional statistical techniques for estimating POD provide an estimate of the mean of the POD
distribution. That is, the traditional techniques provide an estimate of the POD that one would obtain by averaging over all of
the different sources of variability captured by the POD experiment. This focus on mean POD (and its associated lower
confidence bound) ignores inspection variability and has the potential to provide an overly optimistic impression of POD
when there is considerable variation. In this paper, the authors describe an extension to the traditional reporting of mean
POD that accurately reflects NDT variability and the risk of having an inspection that will have poor performance.
Auteur(s) : LI M., SPENCER F.W., MEEKER W.Q.
Affiliation(s) : REANCON, Centerton, Arkansas, SFHire, Albuquerque, New Mexico, Center for Nondestructive Evaluation and Department of Statistics,
Iowa State University, Ames
Pays : Etats-Unis
Vraisemblance des indications : que faire lorsque la probabilité de détection demeure incertaine
Profile likelihood: what to do when maximum probability of detection never gets to one
The statistical techniques in MIL-HDBK-1823A work for the large majority of situations, but not all situations. When the
model (any mathematical model, not just a probability of detection [POD] model) does not have the same characteristics as
the data, then it is the wrong model. Two, not uncommon, examples are a POD minimum value that never approaches zero,
perhaps due to background noise, or a maximum POD that does not approach one, possibly a result of an occluded
inspection site, while the Mll-HDBK-1823A requires asymptotes at both zero and one. The authors discuss a statistical
procedure for adding an asymptote to the standard POD model, estimating its most likely value, and computing confidence
bounds on that estimate.
Auteur(s) : ANNIS C., ALDRIN J.C., SABBAGH H.A.
Affiliation(s) : Statistical Engineering, Floride, Computational Tools, Gurnee, Illinois, Victor Technologies, LLC, Bloomington, Indiana
Pays : Etats-Unis
Les défis posés par la fiabilité des contrôles non-destructifs
Challenges to nondestructive testing reliability
Nondestructive testing (NDT) technology has multiple origins that range from tools and expertise developed by craftsman to
assess the excellence of their own work to an integral element of modern materials evaluation, production processes,
assessment of structural integrity, and service life extension. NDT procedures were developed by trial and error for each
application, and the discrimination capabilities were unknown but acceptable if protected by large safety factors and
reduction of scrap or failures. NDT is unique in providing no (or little) direct feedback to validate success in a specific
application. Large margins have been traditional in engineering measurements and applications of new technology and are
usually supported by a functional test such as proof loading, temperature exposure, and so on, until confidence is gained in
both applications and practices. In the absence of validated NDT capabilities data, unsupported assumptions and beliefs were
developed. It was not uncommon to encounter beliefs that no cracks existed after completion of an NDT procedure. The
pass/fail concept was institutionalized by document selling organizations (ASTM International, SAE International, the
American Society of Engineers, and so on) as procedures for success in various industry applications. The detection
capabilities, limits, or boundaries of applicability were not known, and ranges of application were not indicated. NDT was
often managed as a series of fixed quality assurance procedures. When a failure occurred, the NDT technician was often
blamed, more training was recommended, and nothing substantive was suggested. Focus on personnel training and skill
qualification produced aids such as SNT-TC-1A and the ASNT NDT Level III programs. Little attention was given to variance in
application or quantitative measurement data development. As material property limits and design engineering practices
improved, the demand to understand and quantify small discontinuity detection capabilities of NDT techniques, procedures,
and applications increased. Tremendous advantages in design efficiencies, weight reduction, and structure life extension are
possible by detection of small discontinuities. Confidence in reliable detection of small discontinuities by NDT was
demanded, but was not supported by NDT engineering or engineering data.
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Auteur(s) : RUMMEL W.D.
Affiliation(s) : D&W Enterprises, Ltd., Littleton, Colorado
Pays : Etats-Unis
Source : Materials Evaluation, vol.73, n°1, 2015, pp.38-42 (5 pages) , en anglais
Conception d'un système perfectionné d'inspection automatisé pour composants aéronautiques
basé sur le ressuage fluorescent
Design of an advanced automatic inspection system for aircraft parts based on fluorescent penetrant inspection analysis
Non-destructive testing (NDT) of aircraft parts has become increasingly important in improving the safety and reliability of
the aerospace industry, especially in the testing of high-temperature and high-pressure turbine engine parts. Among the
various types of NDT methods available, fluorescent penetrant inspection (FPI) is comparably more cost-efficient and is
widely used in NDT on aircraft parts. However, current FPI still requires considerable labour forces in its processing,
inspection and analysis procedures. In this paper, we have developed an advanced automatic inspection system (AAIS) that
uses image processing and pattern recognition techniques to aid human inspectors. The system can automatically detect,
measure and classify discontinuities from the FPI images of aircraft parts. Tests have been performed on the sample images
provided by our industrial partners to evaluate our developed AAIS. The test results demonstrate that the developed system
has significantly improved the efficiency of FPI with satisfactory accuracy.
Auteur(s) : ZHENG J., XIE W.F., VIENS M., BIRGLEN L., MANTEGH I.
Affiliation(s) : Department of Mechanical & Industrial Engineering, Concordia University, Montreal, Département de génie mécanique, L’École de
technologie supérieure, Montreal, Department of Mechanical Engineering, Polytechnique Montreal, CNRC Aerospace Manufacturing Technology Centre,
Montreal
Pays : Canada
Utilisation de la décomposition modale empirique et d'un algorithme flou pour l'analyse de
radiographies de soudures
Using empirical mode decomposition and a fuzzy algorithm for the analysis of weld defect images
Radiography is one of the most important NDT methods used for different applications, such as the evaluation of defects and
the recognition of damage in a weld through radiographic images. The correct inspection of radiographs and evaluation of
the weld images are dependent on both the image quality and on the interpreter’s experience. In practice, the images are
often very noisy and have a low contrast. Therefore, some methods of processing are required to improve the image quality.
Here, empirical mode decomposition (EMD) and the fuzzy method have been used to detect weld defects in radiographic
images. For the detection of a weld defect, the EMD components of the radiographic images are extracted and then the
locally lower and higher spatial empiquencies in the image are used to evaluate the weld defect. The fuzzy method is applied
to the images to enhance the contrast. These results show that the combination of EMD and the fuzzy method can detect the
kind of weld defect with up to 86% to 95% accuracy.
Auteur(s) : MOVAFEGHI A.
Affiliation(s) : Department of Nuclear Safety and Radiological Protection, NDT Labs, Nuclear Science and Technology Research Institute (NSTRI), Tehran
Pays : Iran
Système mobile de radiographie X à haute énergie pour le contrôle non destructif des conteneurs
de frêt
Mobile high-energy X-ray radiography for nondestructive testing of cargo containers
Radiologic evaluation techniques are nondestructive testing (NDT) used to detect the bulk of explosives and contraband
materials in large objects. As compared to conventional low-energy (inf. 450 keV) X-ray imaging, high-energy (sup. 1 MeV)
digital X-ray radiography is required for the NDT of large containers because of the need for high penetration through thick
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materials, sensitivity, and the ability to distinguish between low- and high-Z materials. Mobile, high-energy, and high
resolution radiologic techniques are useful to detect contraband and threat materials in digital radiographic images of
containers with complex packing. This paper presents a mobile, high-energy X-ray radiographic technique for the in-field
nondestructive inspection of cargo containers. The developed experimental technique consisted of a betatron as a highenergy (7.5 MeV) X-ray source and a high-resolution (400 µm) matrix detector for the digital X-ray imaging. In order to
evaluate the detection efficiency and image quality of the measurement technique, a test specimen was proposed that was
made of a 3 mm thick steel container with an inner dimension of 60 x 30 x 40 cm3 comprising different low- and high-Z
materials. Image quality indicators were used to assess the essential image quality parameters such as image basic spatial
resolution, effective attenuation coefficient, and signal-to-noise ratio (SNR). Experimental investigations were performed on
a 6.1 m sea freight container with mockup dangerous materials in complex packing. Preliminary experimental results showed
that the proposed technique was able to distinguish between liquids and solids, as well as detect contraband materials.
Furthermore, a remarkable SNR of approx. 400 was achieved in the measured digital X-ray images. The influence of
temperature on X-ray radiation dose rate at different X-ray energies was also investigated. Finally, important applications of
the proposed technique in the context of maritime security are discussed.
Auteur(s) : KOLKOORI S., WROBEL N., HOHENDORF S., REDMER B., EWERT U.
Affiliation(s) : Department of Non-Destructive Testing, BAM Federal Institute for Materials Research and Testing, Berlin
Pays : Allemagne
Cote ISDOC : ME201502.175-185
Industrie automobile
Améliorer la formabilité d'assemblages en aciers dual phase destinés à l'industrie automobile
réalisés par faisceau laser avec refroidissement localisé
Improving formability of laser welded automotive dual phase steels with local cooling
A new laser welding process with the local cooling was presented and applied to two automotive dual phase steels, DP780
and DP980. The microstructure, microhardness, tensile properties of welded joints and limiting dome height (LDH) of welded
blanks were investigated. It is observed that the local cooling during laser welding process can greatly reduce the martensite
tempering and thus reduce the heat affected zone softening. The laser welded joints with the local cooling all failed at the
base metal, and exhibit the comparable strength and ductility with the base metal. For the welded blanks with the local
cooling, LDH is increased significantly, and failure initiates from the weld and propagates perpendicular to the weld.
Auteur(s) : WEI C., ZHANG J., YANG S., SUN L., TAO W., WU F., XIA W.
Affiliation(s) : State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, GM China
Science Laboratory
Pays : Chine
Industrie aéronautique et aérospatiale
Réaliser un commutateur parfaitement étanche pour l'aéronautique
Creating a leak-tight aircraft relay switch
How welding dissimilar metals, including copper-nickel and low-carbon steel, brought this important piece to life. Pure
metals and alloys have widely different constituents, including thermal conductivity, strength, and vapor pressure. Welding
dissimilar metals, therefore, creates challenges that are specific to the nature of the combination you are trying to weld. Over
the years, analysis of these combinations has allowed tabulation of some results.
Auteur(s) : TRILLWOOD R.
Affiliation(s) : Electron Beam Engineering, Inc., Anaheim, Californie
Pays : Etats-Unis
44
N ° 02 /2 0 1 6
4 mars 2016
45
Industrie électronique
Soudage des batteries : un guide pour le choix et la mise en œuvre des procédés d'assemblage
Battery welding: a guide to selecting and using joining technologies
Batteries and battery packs have become an integral part of everyday life in response to the ever-increasing demand for
portable electronic devices, cordless power tools, energy storage, and hybrid and electric cars. This, in turn, drives the need
to manufacture batteries and battery packs that meet the quality and production requirements for these products. There are
a number of materials joining requirements for battery manufacturing, depending on the specific type, size, and capacity of
the battery. Internal terminal connections, battery can and fill plug sealing, tab-to-terminal connections, and external
electrical connections are a few key examples. Several joining options can be considered for each of these operations, such as
resistance, ultrasonic, micro-gas tungsten arc welding (GTAW), and laser welding, including the newest fiber laser options.
The decision to use one or the other is generally dictated by the specific type of weld required and production requirements.
Ultrasonic welding is commonly used for joining the internal electrode battery materials, which are usually constructed of
thin foils of aluminum and copper. The remaining joining requirements, including the connections inside the can, and
external terminal tab connections, are well suited to resistance, micro-GTAW, and laser welding. For can and plug
applications (seam sealing), laser welding is the joining technology of choice. The following is an overview of resistance,
micro-GTAW, and laser welding technologies, along with examples of battery joining applications, detailing when and where
to use each technology.
Affiliation(s) : Miyachi America Corp., Monrovia, Californie
Pays : Etats-Unis
45
N ° 02 /2 0 1 6
4 mars 2016
P UB LI C A TI ON S A NA L YS E E S
45
LISTE DES PUBLICATIONS ANALYSEES
Insight, vol.57, n°1, 2015, pp. 40-47 (8 pages)
Insight, vol.57, n°2, 2015, pp. 74-77 (4 pages)
Materials Evaluation, vol.73, n°1, 2015, pp. 96-99 (4 pages)
Materials Evaluation, vol.73, n°2, 2015, pp. 175-185 (11 pages)
Science and Technology of Welding and Joining, vol.20, n°2, 2015, pp. 172-180 (9 pages)
Welding Journal, vol.94, n°1, 2015, pp. 40-42 (3 pages)
Welding Journal, vol.94, n°2, 2015, pp. 32-36 (5 pages)
Welding Journal, vol.94, n°3, 2015, pp. 91s-100s (10 pages)
Welding in the World, vol.59, n°2, mars 2015, pp. 307-315 (9 pages)
Welding in the World, vol.59, n°3, mai 2015, pp. 317-323 (7 pages)

n°02/2016 - Institut de Soudure

Transcription

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