How to add carbon to steel.

[jgourlay]

You have two things.

1. low carbon steel
2. A lump o' coal.

How do you get the lump o' coal into the low carbon steel to make high carbon steel?

[Rich Hale]

Actually there is another solution to this problem, which I will get to later in this post.
For a long time I have heard of the old smiths that could increase the amount of carbon in a bar of steel with hammer and forge and coal...And have also heard of charcoal being used. Now I supose there are couple of questions that we need to find answers for. One you can do as some claim, sprinkle a bit of coal or charcoal dust on the anvil and pound the hot bar onto/into it and after a few rouinds of this you could spark test the piece and compare it to a piece of the same stock you kept as a test sample. You could also forge weld a piece of high carbon steel to the low carbon and cut stack and reweld it until you get enough layers. .
If you wonder why a smith would go to the trouble of all of this work to get a higher carbon steel it is simple. They did not have the resources then as we have now.
Here is the other solution,,,buy some high carbon steel or recycle some..get what you want and make what you wish from it. Enjoy

[oakwoodforge]

To answer your question: Time, Temp and air ( O2 control ) ... Carburizing mild steel or iron takes lots of time and fuel and is not easily, predictibly or econimicly done in small batches without LOTS of practice. If you need High carbon steel why use $100.00 worth of Coal/charcoal to get $5.00 worth of marginal quality semi-carbon steel with unknown properties? If you can't get any High carbon steel localy try ordering from some place like Clark and Osborne, A 3 foot long peice of 1/2 inch diameter O-1 High carbon steel will cost only about $6.35
ToolAndDie.com - The Toolmakers Marketplace: Oilcrat (O1) Drill Rod 3 feet Long
Hope this helps

Jens

[bruce wilcock]

change your low carbon steel ,for wrought iron and you will easily steel it up in a coal forge by working it at full welding heat folding and refining it driving out the slag and caburising it ,if you throw some casenit in the fire you will land up with a type of blister steel, if you fold that in ,or get some silver steel and have a easy life

[ThomasPowers]

Unless you are careful you are more likely to lose your carbon layer to scale than to increase the carbon content of the piece while forging it.

Also coal has sulfur in it something you *DON'T* want in any steel you make.

In general the old way was to enclose it in a refractory container with carbon compounds---charcoal, leather, horn scrapings, etc and heat as hot and as long as possible.

Theophilus mentions this in a book he wrote in 1120 AD, "Divers Arts", when he mentions greasing a file and wrapping it in leather and then encasing it in a good clay and then heating till it's red.

nb: coal was not used by blacksmiths till the high to late middle ages and charcoal was still the preferred fuel for much longer. (see Abraham Darby and his work to commercially smelt iron using coal instead of charcoal in the 1700's!)

You can also use "natural steels" naturally high carbon blooms from your bloomery.

And for an off the wall method the UN book on blacksmithing tells hoy you can use cast iron as a hardfacing compound for mild steel, heating both pieces and "crayonning the cast iron onto the steel".


Thomas

[bruce wilcock]

yes you are right you have to be verry carefull to get the blister folded in without it crumbling and loosing it. Have you had a try at putting a wash of cast iron on steel ,i have found that when working with a cupula all the lances and pokers have a coat of iron thats has hard as flint, though i never thought of using it as a wear resistant tool, can you find out more about rubbing a cast wash onto steel,its worth giving it a try .

[Dan OHare]

Man I love this forum... so much good stuff here. My question is how does one add carbon to something BIG, like say, a buggy axle. Lots of wisdom from oakwoodforge but even today, as in days of yore a smith is likely to use something from the heap first rather than seek a specific piece new and take it from there. Once I watched a man named Herschel House "add carbon" to some small pieces he had just forged, gun parts, a flint hammer and a frizzen. These were small bits of iron which he placed in a crucible of about cup size with some hardwood charcoal from his forge and steeped it in his fire. At this point he mentioned what Thomas cited, horn or leather could be used here as all organic matter is carbon based. He made it all look so simple and I don't doubt his work as many a backwoods smith did just this for many a rifle. Could this be done on a larger scale, such as for a long rod like a buggy axle or anything else of that size. Some of us LIKE doing things the hard way for the sake of nostalgia. Dan

[Rich Waugh]

Nope, the idea is to keep the carbon in and oxygen out, but creating pressure isn't necessary. Something combustible (the carbonaceous material)in there burns up any oxygen that might creep in.

[Rich Waugh]

Nope, it doesn't have to be sealed super tight; you're not trying to move the carbon into the steel by creating pressure. The carbonaceous material in there will burn up any stray oxygen that creeps in.

[Woody]

Ferrous:

what you are describing is "Case Hardening" it does impart some additional carbon to the metal part, but the depth of penetration is only a few thousandths of an inch. You can check Richardson's Practical Blacksmithing, I believe it has several pages on the process. If you had a forge big enough to handle a buggy axle, you could case harden it, but the results would be the same, an axle with a hard layer that is only a few thousandths of an inch thick. Rather than an exercise in nostalga, I fear it would be an exercise in futility.

Woody