The solution treatment after doing the heat treatment mannered null precipitation

摘要

PROBLEM TO BE SOLVED: To provide a heat treatment method, by which the retained austenite structure in a precipitation hardening type stainless steel can effectively be removed. ;SOLUTION: After executing a solution treatment to the precipitation hardening type stainless steel, a sub-zero treatment is immediately executed, and successively, a precipitation hardening treatment and again, the sub-zero treatment are immediately executed. The retained austenite structure shown again after the precipitation hardening treatment in spite of its removal in the former sub-zero treatment just after the solution treatment, is transformed into martensite structure by the latter sub-zero treatment just after the precipitation hardening treatment to remove the retained austenite structure.;COPYRIGHT: (C)2000,JPO