ATS-34 Heat Treat sample - -

[rlinger]

I may have hit it real good on this HT and thought I would share it. I haven't done any retention testing on it, and won't on this particular blade, but it is hard as rocks and sharpens like working butter compared to some others I have treated. I came by this recipie by tweeking some ATS-34 HT'ing notes I had kept from other ATS-34 work. There is nothing special about the stock and is the same stock I have used for two or three other knives. The blade is a full-V grind and the edge was a mere approx. 8 mil thick. The blade was not cryo'd but that fact does not make it better.

- - -

I put the foil wrapped blade in the room temperature HT oven.

Ramp to 1450 F. and hold for 5 minutes., Ramp to 1965 F. and hold (soak) for 25 minutes.

Rapid air quench to no less than but approx. 150 F. (I used a light air compressor to provide air flow over the foil wrapped steel packet.)

Hold in secondary pre-heated oven at 200 F. until primary oven cools enough to use for tempering.

Place in primary oven and ramp to 950 F. and hold for 2 hours 15 minutes (first temper).

Remove and still air cool to room temperature.

Temper again at 950 F. for 2 hours 15 minutes.

Roger

 

[Mike Hull]

I could be wrong, but I believe you are holding at 1950, about 20 minutes too long. Everything I have seen is 1/2 hour for every inch of thickness. On typical blade thickness', five minutes is usual.

 

[Epsilon]

15-30 minutes seems pretty normal to me, for a steel like ATS-34 that is. 5 minutes seems too short for ATS-34 unless you are austenitizing ungodly high. Mike, the thickness rule changes in high alloy situations like ATS-34 is all. Need for greater solution.

rlinger,
Sounds like you got yourself a formula there. You should try snapping a piece to inspect grain size and then test for hardness. That should give you a nice well rounded idea of your results. Question though... in your secondary oven, why not just make that your tempering oven? Instead of using it as the PQSR prior to tempering in your main oven? Just curious is all.

Keep up the good work.

Jason

 

[Mike Hull]

Yep your right, I was looking at the 440C specs.:footinmou

 

[rlinger]

That is just a toaster oven. I use it to hold quenched steel from falling below an absolute minimum while waiting for the HT oven to cool back for tempering.

Roger

 

[rlinger]

Soak times for ATS-34 extend to the 40 minute range at 1950 to 2000 F.. My limited experience proves this a bit long for knife edge thicknesses. Not that there is edge deformation but rather enlarged grain structure. Another large consideration, for me, is not to allow any steel to fall below approx. 125 F. before the first temper session. I base this last statement on both advise given me by Tim Zowada and published writing. This is why I only grind decarb, if any, after at least a snap temper.

Roger