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Old 04-12-2018, 11:37 AM
samuraistuart samuraistuart is offline
Steel Addict
 
Join Date: Dec 2012
Location: San Antonio Texas
Posts: 163
Thanks Kevin for taking the time to discuss the "How to heat treat Aldo's 52100 steel". I get tired of doing it. I first learned it from you, and discussed it with a few others just to make sure (not that I doubted you, I just don't want to be guilty of only listening to one version of how to do it). Since I followed the recommended method you showed us, and showed us WHY, I have gotten consistent results with Aldo's 52100. 66+hrc post quench, every time. I do the 1650f normalizing for 20 minutes, just to make sure that carbon is freed from it's spheroid bond, and then air cool it to room temp. Then I thermal cycle it around critical temp to help make sure aus grain is as fine as I can reasonably get it, and will usually quench on the final thermal cycle, around 1425f. I then austenitize at 1475 for 10 minutes, and quench in 130f canola (a commercial medium speed oil would be nice, at least I have P50 for W2 and 1095). I do put it in the 0°f freezer for 30 minutes, not for a bump in HRC (that isn't going to happen), but just "peace of mind" in that I am getting the most retained austenite I can convert. The way I see it, 0°f is better than 75°f room temp. I bet I am only converting 1% of RA, if that! But it is for peace of mind, nothing more. LN2 certainly isn't needed, and dry ice/acetone is a hassle to go get, and isn't needed either, really. My post quench HRC is around 66-67, so I have to temper much hotter than the industry charts show.

Interestingly, the 52100 from Chuck at AKS indeed is finely spheroidized. I can skip the normalizing and cycling and go straight to hardening. Same results, and quite a bit of time and energy saved.
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