How to add carbon to steel.

[ThomasPowers]

At Quad-State a couple of years ago Ric Furrer demonstrated 3 ways of making steel; One was melting in a crucible, one was making blister steel and one was in a charcaol forge making orishnaghane (sp).

For making blister steel they used to put 1" steel bars in refractory boxes with carbon compounds and heat to red for a week to 10 days---this may be repeated! (even at the time of the ACW steel could be 5 times the cost of iron).

The resulting blister steel could be used as is or cut-stacked-welded to make shear steel that was a bit more homogenious and that repeaded for double shear steel---so you could have double blistered double shear steel if you were really picky.

The "o" method was to take small bits of wrought iron (rivets, nails---small cross section stuff) and put them in the charcoal forge and heat them for an hour or more to soak in carbon. You then weld up the scraps into a solid piece of steel.

How an old times smith would do a buggy axle? Weld some steel on the ends and forget the rest that doesn't need it!. He could do this by welding a steel piece on the ends or wrapping the ends with a steel "sheet". Since they used to weld up the drive shafts for ship engines they were able to get good enough welds for a buggy axle...

A source of info would be "Steel Making Before Bessemer, vol 1 Blister Steel, vol 2 Crucible Steel" (need to check that title when I get home)

Also "Mechanics Exercises" by Joseph Moxon discusses the various wrought iron available around 1700 and what each was good for.

"Practical Blacksmithing", Richardson, has a lot of info from the late 19th century when the switch from real wrought iron to Bessemer steel was taking place in the smithy. It's a collection of articles from a Blacksmithing Journal of the time.

Thomas

[jgourlay]

Great information all, and thanks. Here is the reason I ask. I work with several chemists and several metallurgists.

I posed this as a simple question to many of them. At first they gave the flippant answer of, "you just add carbon to molten iron" with "stupid" being the subtext.

So then I started asking things like, "well, at that temperature, how do you keep the carbon from simply burning off as C02?" and "with such different densities, won't the carbon just sit on top of the iron?" and "will the iron wet the carbon?"

That just got gaped mouth stares and stumped expressions. So, I thought I'd throw it up here....and sure enough get better answers. Not that I plan on doing this, it's just monkey curiosity.

[Jeff Mack]

Originally Posted by ThomasPowers

For making blister steel they used to put 1" steel bars in refractory boxes with carbon compounds and heat to red for a week to 10 days---this may be repeated! (even at the time of the ACW steel could be 5 times the cost of iron).

Thomas,

Does the box need to be truly sealed, or just real close. I'm paranoid about butting anything sealed in a forge. A little moisture could ruin my day.

Thanks!
Jeff

[ThomasPowers]

Their idea of sealing was to lute the seam in the box with clay---a fairly porous non pressure seal. The idea is to keep the C0 *in* the box in content with the metal and away from the possibly contaminated (sulfur) combustion gasses.

I remeber a mosaic damascus demo at Quad-State where that very question came up. The demonstrator had mad a Ni form and put it in a piece of square tubing and filled around it with shot blasting medium and had the helper go weld the top on (after a shot of WD40). Turns out that the helper was better with the arc welder than the demonstrator was and while the box was heating it "popped". No excitement though.

Thomas

[FredW]

Interesting post. I am going to try the box method of making a steel billet (for knives). I have some high nickel iron powder and graphite. My plan was to weld up the billet inside a mild steel case with a mixture of the powder graphite and some pieces of high carbon steel (shavings probably). Now I think when I weld it i will leave some of the seam unwelded.

You could also add carbon, if you wanted to melt the steel, is add graphite, charcoal, coal, etc. to the charge then through charcoal on top. A fairly thick layer to keep out the O2. The ashes will help to seal it theoretically. I guess you could even use glass on top.

Fred

[oakwoodforge]

Very thorough article on Ancient carburisation of iron to steel:
Ancient carburisation of iron to steel: a comment
A bit dry perhaps but an interesting read none the less.

[ApprenticeMan]

JPH does case hardening, it was a really interesting process to talk wiht him about it. I never even heard the word plumbago before.