Originally Posted by
Larry Williams
I started reading all the old texts containing heat treating information I could get my hands on. When they did mention judging the phase change to austenite it was always cryptic. I found descriptions like, "when the steel opens", "when it sweats", "when the flux rises." Never any mention of color or magnets. Then I found a better description in a 1938 Machinery's Handbook in a section on heat treating high speed steel. I knew I'd seen what was described as soon as I read it.