| 摘要 |
PURPOSE:To relieve a hardening strain under a small load in a short time by leaving a prescribed amount of retained austenite and applying external force for strain relief in a martensitic transformation stage. CONSTITUTION:A member is carburized and hardened so as to leave 20-30vol% retained austenite by adjusting conditions during the carburization and hardening such as the carbon potential of the atmosphere and the hardening temp. External force is applied to the carburized and hardened member, and the hardening strain of the member is relieved by subzero treatment at a temp. at which retained austenite can be transformed into martensite. Thus, the hardening strain can be relieved under a small load in a short time. |
