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case hardening with sugar

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I came across this video on youtube and wanted to share. I was unaware you could buy a set of files with varying hardness to test the hardness of steel.  The guy took mild steel bar and put it in a foil pouch with sugar and bakes at 1700 for 4 hours, then quenched in water getting a harness of 55R approximately.  Quenching in oil did not harden.  Sticking a hot blank in sugar also did not harden.  If you have a kiln I could see this as useful for marginal stuff like rail road spike knifes. 

 

https://www.youtube.com/watch?v=XvkmmoXriNI

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Actually hardening with sugar is an illusion, your pants are just getting tighter your legs aren't getting harder.

I don't know why you couldn't case harden with sugar though don't know why you'd want to. Sugar has a lot of extra junk in it that wouldn't be so good in steel. It might not even be a true case, it could be a layer of contaminated steel say the sulfur. 

Why not just buy a commercial product?

Yes you can get HRC files and they're more accurate than punches without special equipment.

Oh I just noticed this in the knife section, I don't think case hardening is useful for knives or what's going to happen when you sharpen it? Heck, the edge would just roll anyway.

Frosty The Lucky.

 

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Case hardening is possible. It's even possible to go to max depths around 1.5mm. It's just generally not worth it in a world where carbon steel is common as dirt and available everywhere. To get good penetration takes high carbon and LONG soaks at temperature or a Brazillian quenches in toxic kasenite. Pain in the rear. Who wants that for a rr spike knife? Much easier to weld in a bit of almost anything decent or just start with something good.

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No  Chemical reason not to use sugar as a source of carbon.  In fact white table sugar is the largest Volume pure organic chemical available.  It is simply carbon hydrogen and oxygen. Hot enough and decomposes into water and carbon. No sulfur no other mineral compounds.

That said most hardening compound use a number of chemicals that decompose at several different points and create more easily transported carbon compounds. I've  looked at the formula of Kasenite the MSDS available on line gives potassium ferrocyanide (yellow prussiate of soda) as the active component.

However, since our predecessors used formulas containing leather scraps, cow horn, and walnut shells I have to believe that sugar, which they also had available, was not particularly efficient.  

Edited by Charlotte
corrected information

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Of course, the thing that would be more fun to do is try it and see, then post here. "Failure is always an option"...Actually, favorite mythbusters quote is "The difference between science and fooling around is recording the results." Anybody got a kiln and Rockwell tester that wants to play with this?

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I tried the sugar.  It didn't work.  Or, to rephrase that, the tap I made successfully cut only one nut, so the project was successful.  But the case hardening was a failure.  It just is not in contact long enough.  Any carbon bearing compound will work, but the time must be hours, not seconds.

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I read an article years ago that suggested that during the late roman period some blades were made by forging out thin sheets of iron packing them in hardening materials. The resulting hardened sheet were then forge welded together. 

So you could do something like packing sheets of 18 gauge mild steel together in a canister and trying hardening that way.  I'd be interested in knowing the result. 

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Rather then case hardening for a blade use case hardening for light weight hammer head such as for a leafing or modeling hammer. That to me might be worth trying sugar for case hardening out. I've used cherry heat (or is it cherry red?) for the above hammers, and Mark Aspery has used kasenite for them. If I remember right when I took the level ll course from him he said they've lasted for years with no problem. I've also used super quench on light weight light duty hammers and not had issues. Though for my forging and heavy use/weight hammers I use tool steel.

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I'd recommend doing a bunch of research on blister/shear steel before trying to reinvent the wheel.  Been done for a long time before better methods came along.

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To my understanding (while sitting down), Anything with Carbon in it will allow you to "Just in Case" harden something. it is way easier to use a different (proper) Steel to start with, instead of trying to make Honey out of Dog Droppings. I could be wrong, but I haven't heard of a "Wagon Train" crossing this incontinent, for a LONG thyme.:D:D

Neil

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No  Chemical reason not to use sugar as a source of carbon.  In fact white table sugar is the largest Volume pure organic chemical available.  It is simply carbon hydrogen and oxygen. Hot enough and decomposes into water and carbon. No sulfur no other mineral compounds.

That said most hardening compound use a number of chemicals that decompose at several different points and create more easily transported carbon compounds. I've  looked at the formula of Kasenite the MSDS available on line gives potassium ferrocyanide (yellow prussiate of soda) as the active component.

However, since our predecessors used formulas containing leather scraps, cow horn, and walnut shells I have to believe that sugar, which they also had available, was not particularly efficient.  

I'm thinking they just ate the sugar. Wouldn't charcoal be the most efficient at case hardening?

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However, since our predecessors used formulas containing leather scraps, cow horn, and walnut shells I have to believe that sugar, which they also had available, was not particularly efficient.  

My point was and Is that pure carbon in the solid form is not very effective as a hardening agent.  We've got to remember that our ancestors were just as smart as we are and experimented with a lot of different things to produce hardened iron.  A lot of knowledge was lost when we shifted from craft tradition education to formal, academic education. Not everything in blacksmith tradition is necessarily  true but we can be certain that if there was a mixture of commonly available materials that was effective it was tried and accepted or rejected. :D

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Rather than a youtube video of unknown worth; how about the discussion of using sugar for case hardening in "The Cementation of Iron and Steel" Giolitti, Richards, Rouiller  which showed a result of 1.38 C after a mere 408 hours at 950 degC.

 

 

 

 

 

 

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That's a lot of time to soak.  Any idea what the dimensions and original carbon content were?  2% is up into the bottom end of cast iron. Sounds like an interesting book to check out.

 

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It's a great book from back a ways; lots of interesting experiments on if you have to have CO to case harden, (no, direct contact with the carbon donor will work); will diamonds work as a carbon donor, (yes), etc. The discussion of the design of the experiments I found interesting and useful after so many "by guess or by golly" ones I read or see on the web,  I can look up the original dimensions.  Also in this area would be "Steelmaking before Bessemer, Vol 1 Blister Steel"  which is a bit more in how it was done industrially in England

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