Reading through current HSM: Kasenite question.

[Cobbler]

Is there such a thing as a "home brew" recipie for Kasenite?

[Arthur.Marks]

It sounds from the article that the "home brew" ingredients are now illegal to buy. I don't know.

[jungle_geo]

Like Scope stated above, you can achieve up to 0.020 case depth without a lot of effort assuming you can tolerate minor to very minor scaling on the surface.

If I have a surface finish quality critical part that needs to have wear resistance also and don't want to spend a lot of time at the surface grinder or I don't have access to a cylindrical grinder for such parts, I will use the following format to achieve very repeatable results:

I'll soak the over-sized part covered in Kasenite in an oven at around 1650F for 50-60 minutes then I slow cool the part by shutting the oven off and letting it cool slowly in the oven resulting in about 0.020 depth of case.
Later after cooling, I will semi-finish machine the part taking no more than 0.005 off if at all possible to preserve as much of the case as possible. This leaves me with about 0.015 of case hardening left and a high quality surface finish. After the slow cool the part is relatively soft so you can finish machine with HSS and it cuts very nice. If its a part requiring a mirror surface finish I'll leave ~0.001 oversize for the finish grind or less if I just need to buff the part.
I then pack the part in an anti-scaling compound such as PBC and heat to 1700F and water quench.
The quench water will remove almost all the anti-scale compound exposing a perfectly clean part with no added surface imperfections (usually). At this point the hardness is around 56-60 Rc. Temper the part for toughness for an hour (the longer the better) somewhere around 300-500F depending on the application and end up somewhere around 54-45 Rc corresponding to the tempering temperature.
Finish grind or buff depending on the application requirements and you have a great surface hardened part with a mirror finish if required.

One could avoid the whole reheat in anti-scaling compound if you didn't mind grinding the entire part up to 0.005 deep to get below the scale pockets. In that case just quench after the initial Kasenit soak and grind away. If you don't have access to a cylindrical grinder and have a cylindrical part requiring a good surface finish this process has worked great for me only requiring buffing the surface with some 400-600 grit cloth.

I was a little surprised in the HSM article where the author mentioned he achieved a Rc of somewhere in the 30's IIRC. I found that to be rather low based on my experience and almost not worth the effort he went to with building the carburizing chamber, etc.
I usually use 1018, so I'm not starting out with anything special to achieve these results.

[IanPendle]

Someone in these posts on case hardening has mention an anti-scale compound called PBC. Is this a short form for a single chemical or is it a proprietary compound ?

Rgds. Ian.

[Evan]

Google does have it's uses.

Here is a source for "Anti Scale Compound"
Rose Mill Company
122 Park Ave
East Hartford , Conn 06108
PH: 1-860-289-4098

http://www.rosemill.com/

The alternative is to buy a container of 99% boric acid powder roach and ant killer and dust the metal with that. Same thing.

[lazlo]

Google does have it's uses.

Here is a source for "Anti Scale Compound"
Rose Mill Company

Rose Mill is the manufacturer of PBC anti-scale

If you mix the boric acid with alcohol, it's much easier to paint onto the work.

[lazlo]

Is there such a thing as a "home brew" recipie for Kasenite?

Sure, just pack the mild steel with carbon. Old Timers used strips of charred leather belts. Classic case hardening compound is just finely ground charcoal. Bone charcoal and wood charcoal have chemical contaminants that leave beautiful colors on the skin.

The Bullseye Mixture in the 2nd Guy Lautard Bedside reader is charcoal plus a chemical accelerant (barium carbonate).

A good thread about home-brew case hardening mixtures ensued when I asked about the toxicity of barium carbonate:

Barium carbonate toxicity?

[fishfrnzy]

BTW, if you have a part that you want to max out the hardness 8620 is the alloy to use. Should get you a deeper case ( about 2X ) and its core is much tougher. See pages 5 and 23 of below(if my link works):

http://www.emjmetals.com/pdf/bluebook-r.pdf