Strategic Metals Use in the Gas Turbine Industry - Challenges and Opportunities.
Transcription
Strategic Metals Use in the Gas Turbine Industry - Challenges and Opportunities.
Strategic Metals Use in the Gas Turbine Industry - Challenges and Opportunities. Colin Small. © 2011 Rolls-Royce plc The information in this document is the property of Rolls-Royce plc and may not be copied or communicated to a third party, or used for any purpose other than that for which it is supplied without the express written consent of Rolls-Royce plc. This information is given in good faith based upon the latest information available to Rolls-Royce plc, no warranty or representation is given concerning such information, which must not be taken as establishing any contractual or other commitment binding upon Rolls-Royce plc or any of its subsidiary or associated companies. 70 years of development. Metals and applications. Challenges. Solutions? Conclusions. © 2011 Rolls-Royce plc 70 years of development. Metals and applications. Challenges. Solutions? Conclusions. © 2011 Rolls-Royce plc Whittle W1 1941. Weight 700 lbs. Thrust to weight ratio 1.2:1. Gas temperature around 600ºC. Turbine blade material. Ni-20Cr Trent 1000 2011. Weight 11924lbs. Thrust to Weight ratio 5.4:1. Gas temperature in excess of 1800°C. Turbine blade material. Ni-9.6Co-6.5Ta-6.4Cr-6.4W-5.6Al-3Re-1Ti Image © Rolls-Royce plc © 2011 Rolls-Royce plc 5 © 2011 Rolls-Royce plc Alloying additions to Turbine Blades. 1st Generation SX Conventionally Cast 20 18 2nd Generation SX 3rd Generation SX 4th Generation SX Cr Composition (wt. %) 16 14 Co 12 10 8 Ta+W Mo 6 4 Ru Ti Re 2 Al 0 1955 1965 1975 Year 1985 1995 Source: R C Reed, Superalloys: Fundamentals and Applications, Cambridge University Press, 2005 © 2011 Rolls-Royce plc 2005 70 years of development. Metals and applications. Challenges. Solutions? Conclusions. © 2011 Rolls-Royce plc Strategic Metals In Gas Turbines. Alloying Application Applications Typical Components Ni, and Co-based superalloys Ni, and Co-based superalloys Compressor, combustor, HP and LP turbine, exhaust Compressor, combustor, HP and LP turbine, exhaust Hafnium Ni-based superalloys Compressor, combustor, HP turbine, exhaust Niobium Ni-based superalloys Platinum Coatings Coatings Magnetic Materials Ni-based SX alloys HP turbine Combustor, HP turbine, exhaust Ancillaries HP turbine Blades, discs, casings, structural components Blades, discs, casings, structural components Blades, discs, casings, structural components Blades, disc and structural components SX blades Thermal barrier coatings Permanent magnets SX blades Ni-based SX alloys HP turbine Not used - too scarce/expensive Tantalum Ni-base superalloys, metallic metal Compressor, HP turbine, exhaust, electronics Blades, discs, casings, structural components, electrical capacitors Titanium Ti-based alloys Compressor Tungsten Ni-based superalloys Compressor, combustor, HP and LP turbine, exhaust Vanadium Ti-based alloys Compressor Material Cobalt Chromium Rare Earths Rhenium Ruthenium © 2011 Rolls-Royce plc Compressor, and LP turbine Blades, disc and structural components Blades, discs, casings, structural components Blades, discs, structural components Compressor blades Cobalt Chromium Niobium Tantalum Titanium Tungsten Vanadium Ancillaries and Control Systems Cobalt Rare Earths Tantalum © 2011 Rolls-Royce plc Use of Strategic Metals Compressor LP Turbine Discs Blades Cobalt Cobalt Chromium Chromium Hafnium Niobium, Tantalum Tantalum Titanium Tungsten Tungsten Vanadium Combustor Cobalt Chromium Rare Earths Tungsten In Combat Engines HP Turbine Discs Cobalt Chromium Tantalum Tungsten HP Turbine Blades Cobalt Chromium Hafnium Platinum Rhenium Rare Earths Tantalum Tungsten Exhaust Cobalt Chromium Rare Earths Tungsten LP Turbine Discs Cobalt Chromium Niobium Tantalum Tungsten Image © Eurojet Turbo GmbH 70 years of development. Metals and applications. Challenges. Solutions? Conclusions. © 2011 Rolls-Royce plc Challenges. Availability/Costs. Aerospace requirements. Materials usage. Image © Rolls-Royce plc © 2011 Rolls-Royce plc Availability & Costs. Scare resources cost more money. Scarcity, real or perceived? Is your demand significant? What is the cost of qualifying a new material? Image © Rolls-Royce plc © 2011 Rolls-Royce plc Aerospace Requirements. Changes must not invalidate certified products. Aerospace has a huge legacy product range to deal with. Traditional materials have decades of performance data behind them. Limited opportunity to use new technology to backfill on mature products Key issue – We must be able to state that the new material will perform as well as the traditional material for life required © 2011 Rolls-Royce plc Images © BAe Systems Material Usage. For a large engine we typically require…… 6 tonnes of Titanium 9 tonnes of Nickel 6.5 tonnes of Steel … to make a 6 tonne engine. © 2011 Rolls-Royce plc 70 years of development. Metals and applications. Challenges. Solutions? Conclusions. © 2011 Rolls-Royce plc Solutions? Do not use. Minimise. Substitute. Recycle. New alloys. © 2011 Rolls-Royce plc Image © Rolls-Royce plc Do not use. Preferred strategy, e.g. Ru. - 1 – 3% addition to alloy to current generation of SX alloys to improved performance (very effective). - Cost is volatile, $170 per troy ounce in 2011 but has reached $573 in 2007. - World production could not meet demand if used in SX blades. - Will not be used in SX blades. Not usually possible in established alloys (requalification cost). © 2011 Rolls-Royce plc Image © Rolls-Royce plc Minimise. Possibly as alloy composition is a balance of properties. Need to understand the important properties and tailor chemistry for those, e.g. Re. - Alloy element for 3rd and 4th generation SX alloys. - Original alloy design intent was to maximise creep resistance. - Service shows we don’t use full creep life but that environmental performance is a major issue. - Redesign of alloy to meet the in service need – reduce rhenium content . © 2011 Rolls-Royce plc Image © Rolls-Royce plc Substitute Sometimes possible. Recycle OK if bulk addition. Nearly impossible if in trace (ppm) quantities in small components. New alloys Design alloy with cost and supply as constraints as well as the usual property and environmental constraints. Opens up new areas of metallurgy Challenge is that these alloys do not have the traditional balance of engineering properties – need to educate designers and engineers to think differently. © 2011 Rolls-Royce plc Image © Rolls-Royce plc 70 years of development. Metals and applications. Challenges. Solutions? Conclusions. © 2011 Rolls-Royce plc Conclusions. Use of strategic materials is a challenge to the aerospace industry. Need to understand what is making it a strategic metal before you can address the issues. Number of strategies are available to limit use of such metals but it depends on the applications if any of these can be used. © 2011 Rolls-Royce plc