The Making of Wrought Iron

The Making of
Wrought Iron
Denise Diderot
L’Encyclopédie, ou Dictionaire Raisonné des Sience...1751
Copyright Peter H. Kunz. CH-8200 Schaffhausen
The Blast Furnace
Denise Diderot
L’Encyclopédie, ou Dictionaire Raisonné des Sience...1751
When the iron runs in the hearth
and the mold is ready, the
furnace master pulls aside the
hearth-gate. The molten iron
issued from the furnace with
slag floating on the surface.
Skimming it off was the function
of the bar laid across the mold.
Some iron masters preferred to
Protect the metal from the air as
it blackened and solidified. As
soon as the tap was completed,
a workman tossed a layer of
ashes across the still red
surface.
Tools for the Forging Wrought Iron
Tools:
1 Tongs for crude barrens
2 Black smith’s tongs
3 Tongs for iron barren
4 Tongs for round steel
Products:
5 Crude Iron
6 Crude iron barren
7 Preforged rod
8 Rod forged on one side only
9 Completed iron bar
Denise Diderot
L’Encyclopédie, ou Dictionaire Raisonné des Sience...1751
Getting Crude Iron
Pig iron is loaded onto the
hearth through the opening at
the back, and forger shoves the
pig bit by bit towards the flame
as the softened portion is
collected into a “loop.”
Impurities, the “scories”, run out
from the bottom of the hearth.
Denise Diderot
L’Encyclopédie, ou Dictionaire Raisonné des Sience...1751
Forging the Crude Iron Barren
Denise Diderot
L’Encyclopédie, ou Dictionaire Raisonné des Sience...1751
Conversion of the pasty “loop”
into bar iron fit for manufacturing
required four or five heats and
forgings. The successive forms
into which the iron is worked by
the tilt-hammer are shown at
right: the “loop” (Fig. 5), the
“half-bloom” (Fig. 6), and the
“bloom” (Fig. 7), with its two
ends, the “ancony” and the
“mocket head.” In Fig. 8 the
“ancony” has been beaten out to
a bar, and in Fig. 9 the “mocket
head” has been flattened.
Forging of the Raw Rod
The cam mechanism for lifting
the hammer is illustrated in the
forging of the bloom. The great
shaft, bound in iron bands, has
a number of cams to operate the
hammer. As can be imagined, a
forge was an inferno, not just of
heat, but of noise..
Denise Diderot
L’Encyclopédie, ou Dictionaire Raisonné des Sience...1751
Forging of an Iron Bar
Cold water cast on the bloom
at the moment of hammering
assists in scaling off impurities,
and it compounds the banging
of the hammer with the hissing,
almost, the shriek, of water
exploding into steam. This view
shows the hammer being
raised. Notice that he shaft has
to be protected from bloom
and anvil by an iron shield.
Denise Diderot
L’Encyclopédie, ou Dictionaire Raisonné des Sience...1751
Rolling and Slitting Mill
Denise Diderot
L’Encyclopédie, ou Dictionaire Raisonné des Sience...1751
Here is a combination rolling and
slitting mill, which flattens bar
iron and slits the strips into rods.
First the bar must be soaked to a
white heat for at least an hour in
a wood-burning oven. Then it is
progressively thinned and
lengthened between rollers. The
gap between the rollers narrows
from one pair to the next. In this
picture the flattened bar is
passing toward the reader
through the slitting mill. It
emerges as a bundle of rods like
those stacked against the wall at
the left
Binding Rods into Bundles for Shipping
Two workmen bind rods into
bundles for shipping.
They use the little forge in the
background for working the
bands.
Denise Diderot
L’Encyclopédie, ou Dictionaire Raisonné des Sience...1751
End