Need heat treat advice on ATS-34

[bquinlan]

A nearby friend just acquired a temperature-controlled kiln capable for achieving north of 2000 F. So instead of sending away the knife I have ready for heat treat I'd like to try doing it myself.

After trying to do some research I'm more confused than I was when I started. There seem to be a lot of radically different ideas about what temperatures and durations to use for both the heat treat and the tempering phases.

On top of that I'm not clear about how to cool it down. Does it require an oil quench or just air cooling?

Can anyone help me sort this out? I would like to try this myself, but I've put way too much work into this knife to ruin in through ignorance. I may ruin it in other ways, but at least that would be an honest mistake. :-}

--Bob Q

(P.S. The forum search isn't working for me at the moment, so I apologize if this has all been covered before.)

 

[ALIass]

ATS-34 should be air cooled.
IIRC, Terzuola gives great directions on hardening and temper of ATS-34 in his book. It´s a must have IMHO and cheap! (Do a search for Terzuola and you´ll find the title... It´s still early here ) Bob T. is well known as a guy that knows how to treat steel
ALIass

 

[rlinger]

It will need to be atmosphere controlled or the decarburation and scaling will be way to deep. You should aquire heat treating foil for that. The austenitizing soak temperature is about 1950 F. Soak for about 23 minutes and immediately rapid air quench. Upon acheiving hand warm, about 125 F, place in PREHEATED tempering oven (about 600 F). Temper 2 hours, allow to cool outside the tempering oven to room temperature and repeat tempering for 2 hours at about 25 degrees less than the first tempering. Always be sure of the tempering oven temperature accuracy.

Practice on sample pieces of ATS-34 before spoiling your hard work on that blade. You can always send it out until you gain experience heat treating high alloy steels.

RL

 

[Stacy E. Apelt - Bladesmith]

I'm with rlinger on this one.I send mine out to someone who has the right ovens,proper tempering,cryo,etc.All that for a few bucks a blade.It takes a lot more than just 2000 degrees to Ht stainless.Try a few scraps and see for yourself.

SA

 

[bquinlan]

Thanks for the advice. (I'll have to look up Terzuola's book.) You've convinced me to practice on my screwups and send my finished stuff out, at least for a while. That will doubtless save me some heartache.

--Bob Q

 

[rlinger]

Some of the high alloy steels we sometimes like to make blades of do require austenitizing temperatures greater than 2000 degrees F, however that is not the norm. As examples 440C is austenitized in the 1850 F area and ATS-34 and all its cousins I am aware of are austenitized at about the 1950 F range.

For our purposes it is most important to atmosphere control high alloy steels while austenitizing them. Relatively, they require much more time at soak than other blade steels and therefore will decarburize much more deeply if left to an atmosphere of oxygen content.

A cryogenic treatment is recommended for high alloy steels, immediately performed either after a more shallow temper refered to as a 'snap temper' (a lesser temper sometimes performored before tempering) or between the usual two and sometimes three tempers of 2 hours per. Also there are those that prefer cryogenically treating straight out of quench. For many simple high carbon steels that we prefer to use a cryogenic treatment can also be recommended.

RL