Is there a preferred temperature for the air to be at with an air quench on D2? I guess what I’m asking is am I better to air quench over my forge for a few hours in the shop….. or hang it outside in the winter at -20 deg? And why?
I’ve not worked with D2, but I have worked with a fair bit of A2, which has a pretty similar heat treating response from what I understand. A2, once you heat it up sufficiently, will get hard pretty much no matter what you do to it. If you try to anneal it like a conventional steel in vermiculite, it still is hard, but pretty crappy. There is so much RA that it doesn’t even stick to a magnet well, even though it will skate a file. I wouldn’t try slowing down the quench. It will get hard, but I’m willing to bet that you will get a terrible mix of martensite with tons of RA, a little perlite, and maybe some bainite. It’s not gonna be good. Larrin Thomas has some good info on D2.Could you just jam it into some vermiculite, like when trying to anneal other steels? Or does it have to cool faster than that?