Air-Hardening

(Russian samozakalivanie, “self-hardening”), in metallurgy, the acquisition by certain metallic alloys of properties characteristic of their hardened state as a result of cooling in the air after being heated to the hardening temperature. Air-hardening is characteristic of high-alloy steels with a high stability of supercooled austenite in the temperature interval between the critical points and the beginning of martensite transformation. It is also characteristic of some magnesium and other alloys.