On Tue, 13 Mar 2012 11:33:27 -0700, jk wrote:

Stanley Schaefer wrote:


IF you could get wrought iron, you could probably do the "crucible
steel" process with a modern pottery kiln. The old-style steel-making
process was to convert iron ore to cast iron in a blast furnace, cast
iron to wrought iron by burning out the carbon during puddling,

I don't believe that is what is generally considered to be wrought
iron.
WI is produced by Hammering and forge welding on blooms ( The
hammering being the "wrought"ing) And has a fibrous grainy texture due
to slag inclusion.
And what you are describing would be "bar iron" or "puddle steel"
which is considerably closer to mild steel than it is to WI

This is a *really* complicated subject, because there were so many
different processes used to make "finery iron," "sponge iron," "bar
iron," and so on. A bloom could be any of several products, usually
low-carbon iron that could be forged or rolled into wrought iron, or
steel. Some blooms were solid; others were spongy.

But the puddling method was the most common, if not the
highest-volume, method for making wrought iron for at least a
half-century before 1900. It also was used in Germany for making mild
steel.

You can spend a lot of time studying old iron- and steel-making
methods, and for metalworking hobbyists, it's an enjoyable study. At
least, it was for me, back when I was Materials editor at American
Machinist.

Here's a pretty good, if confusing, description of puddling from
Wikipedia. I think it's accurate but I haven't studied it for decades:

http://en.wikipedia.org/wiki/Puddling_(metallurgy)

Wrought iron is basically low-carbon iron with silicate slag
inclusions, hammered out into a stringy composite.

--
Ed Huntress




jk