Just wanted to chime in here to add a little info on cold and cryogenic treatments (-115F and -315F respectively). The general consensus by metallurgists (and keep in mind that that is typically hard to come by; so when everyone agrees, chances are it is right) is that the primary benefit is in cold treating, which converts all retained austenite in most steels, but some steels need the cryo treatment to achieve full conversion. Internal stresses exist between retained austenite and martensite. Once the retained austenite is converted those stresses are gone. The newly formed martensite is