I agree with Scott about the hardness. Nothing wrong with Rc 58-60 kitchen knives, but you should easily be able to get Rc-61-62 from 52100 with the right HT and sub-zero/cryo. On a kitchen slicer, the extra wear resistance can be a big advantage.
Scott-
The HT for 52100 is a bit more complex than a simpler high carbon steel, because the 1.5% chromium makes it act more like an alloy steel. There are two commonly published schools of thought on the HT regime, and variations on those two. Hopefully, all of them are attaining the same results. I feel that if you carefully follow either system, you will get a good blade.
The metallurgical process requires spheroidizing the blade before HT and assuring a fully annealed, fine grain, and stress free blade. The spheroidization will make sure the carbides get evenly distributed in the austenitization. How to attain this is well and frequently discussed, and there is no need to repeat it here.
Once the blade is ready for hardening, austenitize at 1525-1550°F and soak for around ten to twenty minutes.
This is followed by a quench in a good quality medium speed oil.
The quench must be IMMEDIATELY* finished ( * see notes below) by lowering the blade to a minimum of -70°F and holding it there for at least one hour, which can be easily reached with dry ice and acetone ( home freezers don't get to -70°F). As soon as the blade cools in the oil to be cool enough to handle, wash and rinse it off gently, and place in the sub-zero or cryo tank. Whether cryo at -300°F gains any detectable extra toughness by converting the carbides is debated for 52100, but -70°F or lower is required to get full hardness.
Tempering must be done IMEDIATELY* after the blade warms up from the sub-zero treatment. Tempering at a minimum of 250°F is required too convert the brittle tetragonal martensite into tougher cubic martensite. 300°F will yield around Rc63, and 350°F will get Rc61-62.
Temper twice.
*NOTES:
Some use a 30 minute snap temper at 250F to avoid cracks forming in the sub-zero/cryo end of the quench.....and some don't. Both camps seem to claim the same end result, so how necessary a snap temper is, is arguable. It may cause a loss of a point in hardness, but gain several points in sanity for those who can't stand the risk of a blade cracking in HT. My understanding is that the HT guys who do this professionally go from quench to sub-zero in a continuous drop. Some home shops guys recommend suspending the blade over the LN for ten minutes and then lowering it in to allow the blade to cool down more gently. With Dry ice and acetone, I don't think there is any need to delay the quench cooling beyond bringing the blade down to around 100°F and washing it off ( which should cool it more, to about 70-80°F), then placing it in the dry ice slurry.
If not doing a sub-zero/cryo treatment, the temper should follow the quench when the steel has cooled to around 100-120°F. Without the sub-zero/cryo, there will be some amount of stable/permanent RA. This isn't a harmful thing, just something that will affect the final hardness by a point or two.
IMMEDIATELY in 52100 is really immediately. Any delay will result in lower final hardness. The quench does not finish converting the austenite into martensite until it reaches -70°F, so any delay in getting it down to that temperature will aid in stabilizing the RA, yielding lower final hardness.
Use good sense in determining what constitutes a "delay". There is no need to run across the room in a hurry to dunk it in the LN, but don't go eat dinner or wait until morning while the blade is cooling off from the quench, either.
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