Case hardening instructions?

Hey Dave,

There was a thread here on RCM starting December 9/05 Subject: "Casenite/Kasenit" which might prove fruitful if you can do a deja-vu or whatever its called. It was OP'ed by Peter ???, but as I recall there were a few replies, including Jan-Eric. think.

Take care.

Brian Laws>Anyone have a good link to instructions for home case-hardening? I've

It is a highly variable process. For professional info get a copy of Heat-Treating, Cleaning and Finishing, Metals Handbook, Vol 2, 8th edition. The used book sites usually have copies for about $20.

For gunsmithing related refinishing see:

Randy

Ah, perfect. Funny that they start out by saying, basically, "lots of conflicing information out there, so here's our take on it". It's always nice to have someone acknowledge that at the get-go. If everyone has a different approach, chances are it doesn't matter all that much, way I look at it. Thanks for the link!

Dave

Find some _old_stock_ Kasenit. Follow the instructions.

Or else send it out to a commercial heat-treat shop who have liquid baths and the fume extraction to make use of them.

Nothing in the middle seems to work very well. It's not a question of technique, it's a question of materials - and the new stuff just isn't what old Kasenit used to be.

Andy, I didn't know if it was me or the Kasenit. But you say it's the Kasenit that doesn't work as well as it used to, so that mystery is solved. Anyway, what I do now is to heat the part, dip into Kasenit, heat, dip, heat, dip, then hold at dull red heat for a minute or so, maybe two minutes, then plunge into cold water. This method, with the new Kasenit, seems to work as well as a single dip into the stuff when I first learned about it 24 years ago. Finding old stock stuff might be kinda hard. But I do know where about a pound of the stuff is. I think I'll give my old boss a call and see if he wants to give it up. Since I was the only one who ever used it. Eric

It's the Kasenit. Now I'd just like to know _what_ the difference is. I've heard rumours that it's a reduced activity so that there's less cyanide floating out of the hot tin, but nothing definite.

The "sealed box and heat the whole lot" is much better too, but it's long winded and expensive of materials.

To be honest, I just don't case harden any more. Good steels are cheap and commonplace, time is expensive - if I want to harden something, I make it from the right stuff in the first place (Mr Plasma and his friend Mr Pneumatic Belt Sander help too).

If I'm case hardening these days, it's faffing around with Bloody Vikings or some such and we've got tin boxes full of horse toenails to play with.

I think that perhaps the started to wash the contaminants off the hooves before grinding them into the blend. the plant workers are exposed to more than enough horse sh*t from management without having to be exposed to it on the raw feed stock. Gerry :-)} London, Canada

My Kasenit (or the German equivalent) is _very_ old, but it still works. The time you hold the piece at "red-temperature" has influence on the depth of the carbon enriched steel. That's clear. I see that I get enough carbon when, when I quench the part, the color of the hardened part changes. If all the debris/sooth falls off by quenching, it is OK.

Nick

Dave

Basically case hardening is diffusing carbon into a steel surface to get a high carbon alloy on the surface. There are lots of ways of doing that, so there are lots of methods that work. My grandfather, who grew up as a blacksmith, used sodium cyanide. He'd melt it and put the metal in. 1/32" depth per minute was his rule of thumb. He always did it outside and stayed upwind (or did it in the forge) so he didn't poison himself. Frankly, I'm not that confident and happy to pay others to do it.

Jim