Case hardening using sugar

It turns out that my memory wasn't playing tricks on me:
<http://www.thecrossbowmansden.com/Triggers.html .
One interesting thing - they quench in olive oil.
It also turns out that various kinds of liquid soap or detergent also work:
<http://www.practicalmachinist.com/ubb/ultimatebb.php/topic/1/28050.html> .
Kasenite is also used: heat the metal up, roll in the powder, heat to red heat, quench.
If you don't have Kasenite, in a pinch, use sugar: <http://www.nlsme.co.uk/Newsletters/NLSME-August-2005.pdf .
The above methods yield a fairly thin case, and repeated application is used to deepen the case.
Probably, any substance that yields a tightly adherent char will work. I suppose one could as well varnish the item before heat treatment begins. Or barbeque sauce. The process appears to be millennia old.
One can also use the above process and materials to prevent decarburization, which was my original purpose. Decarburization is the opposite of case hardening.
Now, all these examples so for have the metal at a red heat, maximum. Well, some go to orange-red. We'll see if this works at a orange-white heat.
Joe Gwinn

Joseph Gwinn wrote:
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are traditional ingredients.
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Extra vergine? :-)
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Kasenite is the classical method. Not stone old, but quite old. It has the advantage of being faster compared to sugar (later not tried out yet).
BTW: The more traditional and "real" casehardening in the oven is happening in a box (thus casehardening) and takes hours. Kasenite is much quicker and is not for casehardening, it would eat up the heating-elements in an electrical furnace.
Thanks for the links!
Nick

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Nick's talking about pack hardening----a process that can yield a hardened depth of up to .090", given enough time in the oven at the proper temperature.
Harold

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I think you need to get more dictionaries. This is a very old term, and should have had time to diffuse into dictionaries.
Your English is good enough that an English technical dictionary would work, versus a German-English dictionary.
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These are all methods to achieve case hardening, where a surface layer is made much harder than the inside of the iron object in question. Case hardening always involves diffusing carbon into the surface from some nearby carbon-rich substance.
Carbonizing is the process of adding carbon to the surface.
In pack hardening, the iron object is put in an airtight box (made of metal, or of pottery) in a packed bed of powdered charcoal or bone ash or coke or whatever, and the sealed box is held at a red heat for an hour or two, the depth of the resulting case depending on time and temperature.
Another method is immersion of the iron object in molten salts containing some mixture of carbon and nitrogen. The classic is the cyanide bath.
Then there are the coat-and-heat methods, such as with sugar or Kasenite.
Joe Gwinn

Joseph Gwinn wrote:
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It's a technical dictionary for machinery. Getting more and more disappointed from it. I should have bought the two-volume dictionary that would have cost more than 200.- EUR **shrug**
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Sooner or later, I'll buy the Moltrecht (SP?).
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Ah, so case hardening doesn't describe (precisely) how it is done, contrary to box hardening. Should I understand the "case" means the carbon-enriched area and not a case to put something in?
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So I meant box hardening.
Thanks, Nick

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No, Ouch! For that kind of money, one can buy the best of English-only dictionaries, with change left over.
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Actually, I'd get a large but ordinary American English dictionary first. These terms are all old enough that they have found their way into standard dictionaries.
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Yes to both.
I did forget to mention that after adding the carbon to the outside layers, one must do the usual heat, quench, and temper process for the surface to actually be hard.
A standard trick is to do the carbonizing (or carburization) part of the case-hardening process, machine all but the intended hard area away, and then perform the heat, quench, and temper process. Because the metal is in the annealed state, machining is easy, regardless of carbon content. This yields very selective hardening, with sharp borders.
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Well, you can call it that too. The terms are pretty much equivalent.
Joe Gwinn

On Tue, 20 Mar 2007 23:14:55 -0400, Joseph Gwinn
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200 Euros?
The hardbound OED 20 volume set is GBP850 or USD895 or Eur900 (amazon.co.uk/.com/.fr)
That a book published by a British company and then shipped 3500 miles across the pond is only 53% of the price of shipping it 3 feet out of the door in Oxford doesn't surprise me in the least. Nor does the fact that the same book is 29% cheaper when shipped across the channel to the land of the cheese eating surrender monkeys.
Ripoff Britain lives up to its name.
P.S. the leatherbound edition is GBP4000, enough to buy a decent machine tool.

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And the old mountan man method of rehardening a flintlock frizzen("hammer" for you Brits), wrapping the part in leather and clay and heating it up in a fire, then quenching same in cold water. Just about any carbonaceous material will do, saw one writeup for doing color case hardening with flower pots and bean charcoal. Sounded kind of stinky, but I guess it worked.
Stan

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    This reminds me of a story from a co-worker who had been a machinist for several places, in addition to being one in the Navy. He and the others used to play cards while they ate lunch, with their feet on a large wooden box under the table, held shut with wood screws.
    One day, he and a couple of others were told to bring the box outdoors, and set it up with some fans blowing over it to assist the wind. A portable forge was brought up and used to heat some metal parts red hot, while they unscrewed the lid of the box.
    Then, everyone was moved upwind, and the metal parts, still red hot, were tossed into the box, resulting in a billow of smoke which was quickly carried away by the wind and the fans.
    It was at this point that he discovered that he had been eating lunch daily with his feet on a box of potassium cyanide. :-)
    The box was then sealed back up, and put under the table again, and things continued as before.
    While I would like to try KCN hardening, I can't imagine being that casual about it. :-)
    Enjoy,         DoN.

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It's all the same thing, Nick, just a matter of terminology, with pack hardening being one of the methods the objective is achieved. The item is "packed" in carbonaceous material in a container and heated. Another would be gas carburizing, where it's done by the atmosphere of the furnace. You'll even find it called pack carburization.
The purpose is to introduce carbon to the article in question to permit hardening. The case in and of itself does not harden the material, but allows the heat treat process to do so. Carbon content would be too low otherwise. The carbon is introduced in the form of carbon monoxide, a product of heating the carbonaceous materials in an oxygen poor atmosphere, and is absorbed by the steel, which has an affinity for carbon.
The "case" in question is the increased carbon area around the part, or, said another way, the mild steel inside is encased in higher carbon for the purpose of hardening.
Harold

Harold and Susan Vordos wrote:
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Terminology was my problem, not technology. :-)
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That's the trick. Now I understand the difference in the words.
Thanks, Nick

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Originally, but then it went rancid and the Wife threw it out.
I have collected all the old vegetable oil in the house, and it turns out that new corn oil costs less than real quenching oil or spindle oil. Peanut oil is best because it has the highest flash point.
I've read that in the old days, real machinists smelled of rancid lard oil.
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I've read lots about the box method, which has to be millennia old, and when I get a furnace that would be the method of choice. In the meantime, it's all torch all the time.
Joe Gwinn

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Actually, cottonseed oil has a higher smoke point and a higher flash point than peanut oil. I use the oil out of my turkey fryer, cottonseed oil. The shop smells like fried chicken after quenching operations. Might be some schmaltz (sp?) in the pot as well.
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Bacon drippings are used for threading on the lathe, eh? Tom

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Nope, lard oil. Google on same. You can still get it if you look hard enough. Pressed from lard, has nothing to do with bacon(except it comes from the same sort of critter).
Stan

Joseph Gwinn wrote:
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Works great with Kasenite. Also it has the advantage that you can select where you want the part to get hard. Could be done with case hardening to: Case harden it (without quenching) and turn/mill off that part that doesn't have to become hard. Of course you start with a bigger part. :-) Then harden and temper. Has been done that way a zillion of times.
Nick

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Heh! Depends on what you consider "old".
I started in the trade in '57, at Sperry Utah Engineering Laboratories. They were founded in '56, a division of Sperry out of New York. Most of the top brass came from the Greatneck plant, as I understood it, although we also had a few from Bluebell, an operation in the south, Tennessee, I think. Anyway, the project was the Sergeant Missile. We produced the inertial guidance system. The roll pitch and yaw gimbals were all machined from precision aluminum castings, and, due to little miniaturization at that point in time, were fairly large items. The stable platform was approximately 18" in size, perhaps a little larger. Time has a way of erasing these things from your memory.
The point is, the gimbals were machined on a Warner Swasey turret lathe, using lard oil in the sump. While the smell wasn't very strong, it was one of the worst of smells I could think of.
Harold

Harold and Susan Vordos wrote:
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Did you ever work on the ST-80 and ST-120 stable platforms for the Redstone and Pershing missiles by any chance?

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No-------at least no knowingly. My job with Sperry was specifically for the purpose of building the Sergeant, which was taken from the R&D stage through production and phase out in the facility. Fact is, I quit when the project ran out. I say not knowingly, because I have no way of knowing if guidance systems were being produced for others, but if they were, they were identical to the one used in the Sergeant.
Aside from building a huge alignment fixture for the Mariner project, the Sergeant was the only space related item that was built by Sperry Utah to that point in time. They went on to do other defense work, and became one of my customers when I ran my own shop.
Harold

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I've used Kasenit for casehardening in an electric heat treat oven for years, I fail to see the problem.