Wrought iron from cast iron

[Ferrous Beuler]

I have a question. Without the benefit of an advanced education in metallurgical science I cannot provide the answer for myself. Here is my question- Can cast iron be converted into wrought iron?
If so, by what process and could this be done economically by one person in a simple shop. What would be the yield from a small batch of say, 100 pounds of cast.:)Dan.

[RainsFire]

I've been wondering this too, and I think it's possible but difficult.. like making steel I guess..

from what I understand (which is very little) all you would have to do would dramatically decrease the carbon content, and somehow "wrought" it with a flux?
I think you would end up with a mild steel though..

erm, I guess that wasn't helpful lol.. but you would definately need a high temp refractory setup, which is hard in a simple shop.. but do-able.

[matt87]

As I recall, this is how wrought was produced for a few decades; pig iron (carbon c. 4%?) was reduced in carbon content by puddling; melt the iron, blast lots of air over it and stir regularly. See Pig iron - Wikipedia, the free encyclopedia

Finering seems more viable for 'small' scale though Finery forge - Wikipedia, the free encyclopedia
You do have a power hammer, right? ;)

[HWooldridge]

IIRC, wrought iron is the most ancient and primitive ferric-based raw material and was made from iron ore that was often "black sand" or slightly larger pieces of ore. The melts were done at relatively low temps and the puddle was a mass of material that never quite fully melted like cast iron does to fill a mold. It was still a very hot mass and was worked while hot to refine then forged repeatedly if additional refinement was desired. The native carbon content was quite low and tended to be less than .15% along with some level of silica that initially existed in the melt as slag. To answer your question, I think it would be difficult to convert cast iron into wrought. Just based on carbon content alone, you'd be better off starting with mild steel.

[jimbob]

isn't that more or less what has been airing on the history channel; on Japanese sword making; where they cook it for several days in a clay oven, then break the oven open and pull the chunk of steel out

[bipolarandy]

Dan, it "could" be done in a small shop , buy why? Real wought iron isn't that hard to find, factorys churned out tons of it for over a hundered years. and now you can buy Pure iron bars too.
The thing is, with most old steelmaking techniques , you will have a large loss of metal, Even more so when working with wrought iron because of the refining involed.

Take a trip up to the Chittenango Barge Canal Museum in Chittenango, NY. The guys up there have tons of iron they pulled outta the ground from the 1850's, im sure they'd give you a piece if you asked nicely.

[matt87]

IIRC, wrought iron is the most ancient and primitive ferric-based raw material and was made from iron ore that was often "black sand" or slightly larger pieces of ore. The melts were done at relatively low temps and the puddle was a mass of material that never quite fully melted like cast iron does to fill a mold. It was still a very hot mass and was worked while hot to refine then forged repeatedly if additional refinement was desired. The native carbon content was quite low and tended to be less than .15% along with some level of silica that initially existed in the melt as slag.

More or less yes, though it isn't a melt; the process is a reduction or a smelt as (as you point out) the iron never actually melts.

To answer your question, I think it would be difficult to convert cast iron into wrought. Just based on carbon content alone, you'd be better off starting with mild steel.

That's what the puddling or finery process does; it produces an oxidizing atmosphere (one with lots of O2 but little or no CO or CO2). Since much of the carbon in pig or cast iron is in its free state , when it is melted in the furnace the carbon reacts with the 02 to produce CO and CO2; this evectively lowers the carbon content of the iron.

Practically speaking, this is probably not worth it on a small scale -- as HWooldridge and others say. Sounds like a heck of a lot of fun though...

[Ferrous Beuler]

Thanks guys for all the input but this whole notion is beginning to sound a lot like WORK!
Aparently it is possible and would certainly be cool to do, go from scratch to a finished iron product, but it seems like a long row to hoe...Dan

[Shane Stegmeier]

Very cool link to lots of articles on steel and iron production...

A Steel Glossary with Linked References

An aweful lot on the history of iron production and a lot on historic patternwelding too

[woodwalker]

oooo, I just read about this in The Art of Blacksmithing. To make iron, one puts the ore in a really hot fire. after a while, put the fire out and dig out the iron collected at the bottom. Most of it will be cast iron, so build an even hotter fire, and put the cast iron in it. The fire will (or should, I guess would be a better way to put it) burn the carbon out of it, leaving you with wrought iron.

Basically, dig a hole, direct the air from a few blowers into it, and light a fire in it. Tunr the blowers on full blast, and wait.

I won't garintee results, but that's how I read it.