Sub zero quinch or soak?

[Mike22]

Why is the sub zero soak or quinch done? I have heat treated many parts and tempered. What do you gain from the sub zero soak or what else does it do to the metal? Sorry if this seems like a simpleton question.

Thanks

Mike

 

[drysideshooter]

Do a quick search here on the forums or even a Google search and you will find a lot of information.

 

[Boogaloo]

The short answer is that it reduces retained austenite. Some steels have a mf (martensite finish) temperature well below zero thus they must be supercooled to maximize conversion of austenite to martensite.

 

[Karl B. Andersen]

The word is quench.