In a preheated kiln heats steel to the color of orange and leave it to cool down, about three, four hours. A2 belongs to a group of air-hardening steel, is hard to forge, but it made knives are excellent.
The steel (A2) I used to make punches and dies for stamping press. D2 is even better but it's too hard for file work
I know, maybe it's stupid, maybe it's funny, but I'm doing the blade such as a long time ago. Then there was the bolt sanders, grinders, plasma cutters and yet they did great knives.