ATS-34 HT Sample

R

rlinger

Joined
Mar 29, 2002
Messages
4,591
This is a blade I made for a customer that wants it only for field dressing and not to be used for skinning or de-boning. I wanted to shoot for 60 - 61 HRc but no less than 59 and didn't think it should be so hard as 62. I think it turned out pretty well and wanted to share it, as I have been with other HT's in the past.

Here is the HT:
---------------
(foil wrapped ATS-34)

Equalize: 1410 F. / 7 min.

Austenitize: 1950 F. / 22 min.

Rapid air quench

Deep cryo: 13 hr.

Temper: 475 F. / 2 hr. 15 min.

Temper: 475 F. / 2 hr. 15 min.

61 HRc
 
Field dressing is not much of a challenge for a knife unless it's something like a warthog that has been rolling in mud.Any special shape?
 
Thanks for the data Roger.

Hmmmm, 1950, 475 and 61rc? Hmmmm.

I didn't think it'd come out that hard. I just finished my first ats-34 heattreat. I used 1975, 400 and a 6 hour LN cryo. Unfortunately I don't have the hardness tester set up yet. After the quench (aluminum plates) it was very hard.

But I don't know where it is now and am worried about finishing the knife. The file has a hard time with it, but it will bite.

Steve
 
Steve, 6 hr deep cryo may be a little light. However, if it was sufficient enough time to transform the majority of remaining austenite - figure your blade to be 61 - 62 HRc and probably closer to 62 than 61. It would also depend on having a long enough soak time. A couple 600 F. tempers may have given 60 HRc. I base all this on some stuff I've been doing with ATS-34. Download some data sheets and use those specs as the bases of your heat treats, then when possible have your results checked. Make written references of your work. Also, I listen to fellows like Mete and some others here that I believe in.

I did something with this blade I really don't like to do. That is I Rockwelled it before temper. It was 61 HRc as quenched. After deep cryo it was 64. After temper it is 61.

Mete, yes - the elk guide that will own the knife instructed me that it would only be used for field dressing and the only meat cutting would be to ring the back for sawing the back bone so to pack the elk out in halves.

RL
 
Roger,

Hmmm - some more.

The exact recipe I used (based on one given by a master smith that is helping me out) is:

1800 initial temp
1975 20 minue soak
quench with plates (FWIW didn't remove from foil)
left in the home freezer overnight (didn't have any LN on hand, figured as good a place to leave it as anywhere)
file test - very hard
Temper 400 one hour
7.5 hour LN (I figured wrong before)
Temper 400 one hour

Now here's my puzzlement. I've never worked ats-34 before. So I don't know how fast it is to finish. But this blade is so much easier to work than S30V I don't know if it's too soft or if ats-34 is just that much easier.

Steve

PS I'm trying to find a machine shop with a tester I can use.
 
Steve, my experience is it will always be easier to machine than S30V. I think you will find ATS-34 to finish about as well and about as easily as the tool steels you have used.

With care not to break the tip off, do your deep cryo temper before oven temper when heat treating stainless.

I like to equalize during the ramp to better prepare the steel for hardening. My data sheet (the one I like best) specifies the equalize temp. at 1400 F. for 154CM. Don't exceed 15 minutes for equalize. My reference for that is Bill Bryson.

My guess is that your master smith is putting the steel in the 1800 F. oven to help get the steel heated throughout before reaching the target temp..

I believe, because we are quenching thin parts, a rapid air quench is all you need. And, I wonder how you can get the edge properly quenched with two flat plates against a beveled blade. I have never tried it and that is one reason why.

Another thing I consider in determining my soak time is the ramp rate of my particular oven. For example, the vendor data sheet specifies recommended low end of austenitization temp. is 1900 F.. I consider that when ramping from 1900 F. to the target temp.. That also effects the equalize soak that I determine to use.

For my ATS-34 work I have been depending on the Crucible 154CM data sheet and by following it fairly closely I have been able to hit their aim hardnesses.

RL
 
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