Thread: Best custom knife maker NZ

Originally Posted by terryf

Huh?? that's pointless unless you didn't do it properly the first 3 times...

I mean 3 times of tempering in different temperatures, and one final quenching on the edge. I was told by a Japanese metal engineer long time ago.

Originally Posted by Black Rabbit

I mean 3 times of tempering in different temperatures, and one final quenching on the edge. I was told by a Japanese metal engineer long time ago.

That's a process called normalising. It's used to refine the grain structure of the steel after forging and before austenitizing (hardening)

Essential process for a forged blade, you get big grain growth during forging due to the high temps which if left unchecked creates a brittle blade