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Old 02-23-2017, 11:07 AM
samuraistuart samuraistuart is offline
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Join Date: Dec 2012
Location: San Antonio Texas
Posts: 163
Yes...the toughness got better with cryo...not wear resistance. There are charts, most of us have seen them, that claim something like 400% increase in WEAR RESISTANCE with O1 that has been cryoed, over O1 that was not. Now think about that for a minute. If it was wear resistance....then you would spend 4 times the amount of time/effort in hand sanding an O1 blade that was cryoed over one that wasn't. That most certainly is not the case. It isn't wear resistance that is changed...it is overall toughness (due to the cohesion gained between matrix and carbides).

Yes, AEBL is a good candidate for sub zero dry ice. Why? Because of the retained austenite after an AEBL quench. How do we know without X ray diffraction examination? Because the hardness goes up after the sub zero quench! That is RA being converted over to martensite (technically...untempered martensite).

HT is fuzzy, no doubt. Some if it's straightforward. Some isn't. Like re-heat treating SS. It's been said not to do it. But you CAN, depending on the alloy.

Cryo with any steel that has alloying, whether it is Cr, V, Mo, W, whatever.....can benefit because of the carbide precipitation that happens during upon tempering. If those alloys were not in the steel, then cryo would be of less benefit, other than converting the RA over. And especially a eutectoid steel like 1075 or 1084. Cryo isn't going to do much at all with these steels. There isn't hardly any RA (there is a little minute amount), nor are there alloys to allow the carbide precip.

Last edited by samuraistuart; 02-23-2017 at 11:09 AM.
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