The term 'wrought iron' presents difficulties in itself. It is used by
chemists and metallurgists to distinguish it (malleable iron) from cast
iron. However in 18th century usage wrought iron was iron that had been
made into something by a nailer, locksmith, blacksmith, or other
manufacturer. The bar or rod iron that left the forge or slitting mill was
not wrought iron. It was merely iron (or strictly unwrought iron).
Peter King
----- Original Message -----
From: Michael McNeil <[log in to unmask]>
To: <[log in to unmask]>
Sent: 29 November 2000 18:26
Subject: Re: a metal question / 'wrought steel'?
In the stainless steel world "wrought" is simply a term meaning that the
material was made into its final form primarily by mechanical deformation
after solidification, as opposed to cast or weld-metal. Bar, wire, nails,
etc. are common wrought products. This terminology is certainly less common
in carbon and alloy steel products (with which I have worked very little)
and may be eccentric or obsolete.
At least in the SS and nickel alloy world, the wrought/cast difference is
utterly different from the wrought iron/cast iron difference. There are
sometimes minor chemical differences, but basically the composition of
wrought and cast stainless steels of the same basic type are too close for
anyone but a metallurgist to worry about. The differences are in
microstructure.
>>> [log in to unmask] 11/29 11:15 AM >>>
There were a number of ways to make steel. You might want to look at:
Rostoker, William and Bennet Bronson
1990 Pre-Industrial Iron: Its Technology and Ethnology. Archeomaterials
Monograph No. 1, Philadelphia.
Gordon, Robert B.
1996 American Iron 1607-1900. The Johns Hopkins University Press,
Baltimore
and London.
Barraclough, Kenneth C.
1976 The development of the Cementation Process for the Manufacture of
Steel.
Post-Medieval Archaeology 10:65-88.
1991 Steel in the Industrial Revolution. In The Industrial Revolution in
Metals, edited by R. F. Tylecote and Joan Day, pp. 261-306. The Institute
of
Metals, London.
They have pretty good descriptions of the various methods for making steel.
According to what I have read, a bloomery hearth can also be used to make
steel. Needham states that the bloomery was never really used in China to
make
wrought iron. It was used for the production of steel (Gilmour 1999:87-90;
Needham 1980:514-520 and 539). The tatara method used in Japan produces
steel,
as well as cast iron and wrought iron all at once.
Gilmour, Brian
1999 Ironworking in ancient China: a review of two recent publications.
The
Journal of the Historical Metallurgy Society 32(2):87-92.
Needham, Joseph
1980 The Evolution of Iron and Steel Technology in East and Southeast Asia.
In
The Coming of the Age of Iron, edited by Theodore A. Wertime and James D.
Muhly,
pp. 507-542. Yale University Press, New Haven and London.
I'm not a metallurgist so I won't comment too much on "wrought steel".
Except
to say that it might not always be appropriate. Steel made by cementation
would
have been "wrought" or "forged" but I think the historic term is "shear
steel". This steel was a thin layer formed on the outside of bars of low
carbon iron. After processing these would have been pile welded to form a
sandwich of steel and iron. The more times it was cut up and forged, the
more
layers were obtained.
Steel that was produced in bloomeries or the "natural, cullen(?), or German"
steel would not have been. As they would have been steel all the way
through
the bloom. There is some historic evidence, and I can't remember where I
read
it (article by Brian Awty?), that bloomers were rated by the amount of steel
they managed to produce. The more steel the better they were.
Also some steel produced in cementation furnaces was further processed into
"crucible steel". Here it was completely melted in a crucible and the
result
would not have been layered, but a more homogenous material. this is a
later
development in Europe. Again look at the above references for dates and
techniques.
Hope this is of some help.
Jamie Brothers
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