RWL-34 Heat Treat
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Equipment used:
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18 inches deep model Evenheat knife makers oven with RampMaster II controller.
Also used for tempering.
Liquid nitrogen dewar
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RWL-34 Bushcraft Scandi grind about 5/32 max spine thickness
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Stress relieve (after grinding and ready to HT): 1200 F / 2 hr., oven cool to 800 F, still air cool
Preheat: 1400 F / 7 min. (ramp to preheat moderately)
Austenitize (ramp from preheat to austenitize as quickly as furnace allows): 1950 F / 15 min.
Rapid air quench
Snap Temper: 325 F / 1 hr.
Deep Cryo = 12 hr.
Temper: 500 F / 2 hr.
Temper: 450 F / 2 hr
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The blade used in this example tested 60 HRc after final temper.
The tip of tang (about 0.080 to 0.100 inch thick - a hammer ended bushcraft)
tested 58.5 HRc and it was the part of blade closest to the furnace door,
the coolest part of furnace. Another minute or two on the soak
I would not worry alot about but much longer than that could cause brittleness.
I would stay, for a blade of this size, within the 15 to 16 minute soak time.
Ramp moderately enough to preheat to ensure all cross section is at preheat
when preheat is attained. I would not preheat much longer than about 7
minutes but no less than either. After preheat get to austenitizing temperature
as quickly as allowed. I would use no less than forced air quenchant and plate quenching is fine.

I believe there is nothing sacride about the oven cool on the stress relieve.
I do that because it doesn't hurt and it also helps from me accidentally bending
the blade by carrying around the shop to hang up to cool when it is at 1200 F.
So I take a few extra minutes to let it cool in the oven before handling.
Also, it is arguable that the stress relieve is necessary since the remainder
of heat treat may do that anyhow. I won't debate that. I do it because
I don't know any better and it don't hurt to and I sleep better for doing it.

RL