View Full Version : Reading through current HSM: Kasenite question.

12-11-2010, 01:53 PM
Call me a late bloomer, but I just picked up the current copy of HSM. It raised an old question of mine WRT Kasenite. How deep does the case develop? I know with traditional methods, you control the depth with time at temp. Is it the same with Kasenite? I am assuming that it does not add dimension to the part being hardened---i.e. a coating.

Basically, the question is: if you use Kasenite, how much room are you leaving yourself to grind? Can you alter the depth with repeated application / extending time at temp?

12-11-2010, 02:13 PM
My recollection was that it couldn't produce as deep a case as pack hardening or likely more modern methods. This link confirms that with the directions suggesting .020 depth if you're willing to keep it up to temperature for about an hour. (Max carburizing depth is about .05 - .06)


12-11-2010, 02:40 PM
Case hardening is not a "coating", it is an absorption process. Parts will grow slightly, usually only about 0.0001" maybe a little more, or a little less. If your case is critical, it is best to have a professional heat treater do the job for you.

12-11-2010, 03:08 PM
Thanks! Shoulda looked up the manufacturer's page first. Lesson learned. :o

12-11-2010, 04:42 PM
Basically, the question is: if you use Kasenite, how much room are you leaving yourself to grind? Can you alter the depth with repeated application / extending time at temp?

The case can be made deeper by repeated application. I use it regularly and a triple application will produce a case at least 5 to 10 thou deep. I used it on bending dies made from mild steel and they show zero deformation even on the sharp die for hard right angles. It's easy to use, heat to cherry red, roll the part in the powder to coat it and then hold the heat up with the torch for a couple of minutes. Then quench in brine for maximum hardness. The coating springs right off the part during the quench. Repeat if you want a deeper case. Keep a fan behind you to blow fumes away. Although the sodium ferrocyanide is entirely non toxic it does release small amounts of hydrogen cyanide when it decomposes under heat. It doesn't make enough fumes to kill you but why breath cyanide if you aren't being forced to? :eek:

12-11-2010, 06:05 PM
While we're at this, what's the correct pronunciation of the word "Kasenit"?

12-11-2010, 06:54 PM
No idea. The stuff I use is called "Quick Hard". No, it isn't blue....:D

BTW, it is shippable by any method. It is not hazmat and is the same chemical used in table salt to prevent caking.

12-11-2010, 07:18 PM
The stuff I use is called "Quick Hard". No, it isn't blue...
LOL :D :D :D :D

12-11-2010, 07:54 PM
Don't know if it is correct, but I have always heard it pronounced same as Case Knit.

12-11-2010, 10:26 PM
Case N ite

I use it quite a bit, love it. I get case hardening to about .020 with triple heat treat soakings. Smells like hell though, I have set off a few fire alarms over the years in our school using it.......

12-12-2010, 12:45 AM
Is there such a thing as a "home brew" recipie for Kasenite?

12-12-2010, 01:28 AM
It sounds from the article that the "home brew" ingredients are now illegal to buy. I don't know.

12-12-2010, 01:54 AM
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.

12-12-2010, 02:31 AM
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.

12-12-2010, 02:49 AM
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


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

12-12-2010, 10:15 AM
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.

12-12-2010, 10:24 AM
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? (http://bbs.homeshopmachinist.net/showthread.php?t=28292&)

12-12-2010, 02:32 PM
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):