Quenchant for o1 that doesn't require heating?

[kuraki]

My thinking is that the difference in speed between say AAA and 50 isn't all that great. Yes, one is faster, but not so much faster as 50 compared to brine in the mass and web thickness we are typically doing. On a thick block it makes a difference as the exterior contracts so much faster than the interior, but then we quench air hardening steel in plates, or in liquid cooled plates, without a second thought when that is significantly faster than still air.

I just don't believe you can quench an oil hardening steel in the sizes and shapes we're working with too fast in a 50 type oil.

Now if it's already hot, that's another story.

 

[duurza]

If the quenchant is too fast, you could add unneeded stress to the blade. I've used DT-48 on medium speed steels without apparent problems, but it would be interesting to see the microstructures of the steels compared to medium speed oils.

Very true. I did some research and simulation into this a while ago and a general rule that I got out of all that was that if the temp dropped from 815 C to less than 600 C in less than 9 seconds, there would be unnecessary stresses (though very minimal). From below 400 C, O1 can be quenched in ambient air to harden.