Thread: Looking for the best heat treatment for O1

Mr.Blue and some others could speak to this better than I, but the info that I have always been given is that the grain size blow up starts at temps above 1600F or around 871C for the kind of carbon/tool steel that we are discussing unless you have a steel with enough vanadium in it to delay that growth a bit and even then, it will still not be ideal. When guys over here do an initial "normalizing"cycle on spheroidized 52100 to break up the carbides and get stuff in solution, the do it at around 1650F or 898C. The DO get grain growth, but they count on the subsequent lower temperature thermal/normalizing cycles to take care of that. Sounds like you were growing grain at almost eve step of the process.

Originally Posted by gregg71

Exactly.