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Thread: Case hardening compound receipe
09-05-2012, 03:18 AM #1
Case hardening compound receipe
I'm interested in trying case hardening but cannot get Kasenit or Cherry Red or any other specific case hardening compound (living overseas).
In a how-to I found this receipe:
13 parts hardwood charcoal (barbecue charcoal)
3 parts barium carbonate
2 parts sodium carbonate
1 part calcium carbonate
It does not mention if parts are measured by volume or by weight but at least these are all fairly easy to obtain substances. However said document described this mixture for use as a pack carburizing compound, they packed the pieces to be hardenend and this mixture in a box and heated it for several hours.
For convenience I would rather use the torch method; use a torch to heat the part to cherry red color and then dip it in the compound. Is this mixture suitable for this method also or is it not worth bothering?
09-05-2012, 03:36 AM #2
No idea if that changed or if it was at all close to the above formulation.
Measure is by weight, not volume, FWIW.
But check this out - the address is in UK but 'seems' to ship to 'mainland' .. which included CH last time Iooked .. if CH permits the importation:
Or sweep a 50 Km circle off Kloten and there must be someone left still using similar stuff.
09-05-2012, 04:17 AM #3
Thanks Bill, I'm aware that there's Chronos and I think also another seller in the UK, but including the postage it just gets pretty expensive (they charge quite a lot for the compound itself).
I'll continue to have an eye open. As with many other products I guess the problem is not that they're banned or restricted in our country but that there's just not enough demand for it to make it profitable to sell over the counter.
BTW: You seem to know Switzerland a bit ;-)
09-05-2012, 04:40 AM #4
09-05-2012, 04:48 AM #5
Though I've spent far more time in Kantons Zug and Zurich or in and around Brienz, Rinngen, Interlaken, and environs, had it not been for one Bernard Evers, I'd be living in Campione D' Italia maybe, the Ticino, certainly. Language is easier for me there, as I never learned to honk SD well.
09-05-2012, 07:44 AM #6
one of the principal ingredients in Kasenite is potassium cyanide.
This is used as a bleach in B&W fine art photography so if you have any photographers supply stores that would be the place to check.
My machinist teacher in high school made his own out of bone charcoal and potassium cyanide.
Obviously you need to use the same precautions in use as you would with Kasenite
Also if you make the charcoal from peach pits they are a source of potassium cyanide
09-05-2012, 07:55 AM #7
09-05-2012, 08:12 AM #8
Mark Rand liked this post
09-05-2012, 10:05 AM #9
I don't know about this recipe, I have the Cherry red product. But..
the best thing that has ever happened to pack case hardening is 4 or five small fire bricks to make a muffle.
The parts to be hardened are put in a suitable tin, and covered with compound, the tin then sealed except for a small pressure relief hole ;-)
The tin placed in the arrangement of fire brick, and soaked cherry red for as long as you care to hold the torch.
If everything is arranged before hand, the part can be spilled out into water or oil to quench if that's what is wanted.
Just saying, the bricks hold the heat, and save on gas ;-) do what you want.
09-05-2012, 10:31 AM #10
As most of you know, case hardening is time dependent. For any measurable amount of depth, the part has to be held at temperature (>1550F).
This is from Case Hardening Steel : Pack, Carbonnitriding and salt surface hardening
Carbonnitriding starting with low carbon steel (SAE 1008):
1 hour @ 1425 to 1450°F results in a case .004" deep.
2 hours @ 1425 to 1450°F results in a case .006" deep.
3 hours @ 1425 to 1450°F results in a case .009" deep.
4 hours @ 1425 to 1450°F results in a case .011" deep.
1 hour @ 1600 to 1625°F results in a case .015" deep.
2 hours @ 1600 to 1625°F results in a case .021" deep.
3 hours @ 1600 to 1625°F results in a case .026" deep.
4 hours @ 1600 to 1625°F results in a case .030" deep.
Heat Treaters Guide, 1982, ASM, p.25 chart (referenceing Metals Handbook 8th ed., Vol 2, ASM.
09-05-2012, 10:41 AM #11
Potassium cyanide when used as a case hardening will give decent colour case hardening
All in all both are used as a case hardening agent
Small items may be case hardened by repeated heating with a torch and quenching in a carbon rich medium, such as the commercial products Kasenit /Casenite or "Cherry Red". Older formulations of these compounds contain potentially toxic cyanide compounds, such as ferrocyanide compounds, while the more recent types such as Cherry Red do not.Cyaniding
Cyaniding is a case hardening process that is fast and efficient; it is mainly used on low carbon steels. The part is heated to 871-954 °C (1600-1750 °F) in a bath of sodium cyanideand then is quenched and rinsed, in water or oil, to remove any residual cyanide.
2NaCN + O2 → 2NaCNO2NaCNO + O2 → Na2CO3 +CO + N22CO → CO2 + CThis process produces a thin, hard shell (between 0.25 - 0.75 mm, 0.01 and 0.03 inches) that is harder than the one produced by carburizing, and can be completed in 20 to 30 minutes compared to several hours so the parts have less opportunity to become distorted. It is typically used on small parts such as bolts, nuts, screws and small gears. The major drawback of cyaniding is that cyanide salts are poisonous.
09-05-2012, 11:49 AM #12
09-05-2012, 12:07 PM #13
One of Guy Lataurd's Machinists Bedside Readers has a formula in it and instructions. My copies are at home, so I cant tell you which one.
09-06-2012, 03:10 PM #14
The barium carbonate recipe requires a sealed container.
Barium carbonate decomposes around the correct temperature for case hardening, releasing carbon dioxide. The carbon dioxide reacts with the charcoal, giving carbon monoxide which carburizes the metal, the resulting carbon dioxide then reacts with more charcoal and the process repeats.
If it is not closed in, the carbon dioxide and monoxide gasses just leak away.
You may have more trouble getting hold of barium carbonate, than getting hold of a ferro-cyanide.
Despite their name, Ferrocyanides are not particularly toxic, they even get used in food products.
Barium carbonate is toxic, it's a neuro toxin, and causes severe muscle and stomach cramps. The LD 50 (dose for 50% chance of death) for adult humans is about 4 grams.
Although it has no taste, it wouldn't be much use to a poisoner - it would show up on an x-ray as a "barium meal" (the sulphate, used for medical barium meals is only just to say sufficiently insoluble to avoid giving ill effects - there isn't much in it).
Barium Carbonate (witherite) used to be mined in northern England. Most places, it's a mineralogical curiosity, In northern England, there were veins of almost pure barium carbonate. Small amounts were used locally as rat poison, and there are local tales of mine ponies and other animals being accidentally poisoned.
09-06-2012, 07:31 PM #15
Where can you find the chemicals, in rural USA?
09-06-2012, 10:32 PM #16
09-06-2012, 11:43 PM #17
When I was teaching in a technical college, I used to make projects out of mild steel and case harden them by making a steel box with a lid that could be sealed and burying the workpieces in bone meal. I put them in a gas furnace at 1550 degrees for four hours. Bone meal gives off a lot of gas until it becomes charcoal. I would expect the steel being at 1550 degrees makes it permeable, enabling it to absorb carbon from the gasses from the bone meal. This method was produced very satisfactory results, quenched in cold water. You can get bone meal from any farm store, it is used as a supplement in animal feed.
09-07-2012, 07:23 AM #18
Aquarium charcoal is another excellent hardening compound,found at pet stores. It,and bone meal,will both give deeper hardening than Kasenite when used in closed containers. I have personally used these things and can vouch for them.
When I was Toolmaker,I made some parts,such as forked centers for the treadle lathe at the Geddy Foundry in Williamsburg. Just used mild steel. We put the parts in a graphite crucible with bone meal with a heavy lid into the forge. I also put in some 4" long nails. Once in a while,I'd pull out a nail and break it off in a vise to see how deep the case was. After a few hours,it was a good 1/32",so I removed the parts and quenched them,then tempered them to a medium straw.
I don't know why aquarium charcoal is considered better than regular charcoal,but our gunsmith's shop used it and bone meal. It was reputedly made from the bones of laboratory monkeys,but they didn't let the public know that. It could have been the porosity. Not sure if they still use monkey bone.
09-07-2012, 08:43 AM #19
Reading on a BBQ forum one poster said to buy charcoal local to where he was overseas the stuff sold for use in Hookah's was very high quality, and cheaper than most any other source.
Looking on amazon here in the US the hookah charcoal is quite expensive.
The aquarium stuff is usually CARBON not "charcoal", with the carbon being a more refined form ?
09-07-2012, 08:38 PM #20
For small parts, only a torch with Acetylene (C2H2) and oxygen (O2) for fuel can give good results.
Run the flame fuel rich (with a long white cone) the flame is not as hot as it is normally adjusted, but heats slower and does not seem to burn sharp corners in the part.
With white hot carbon in the flame as the source of the carbon will give the steel a nice case when quenched in water.