RING-SHAPED MEMBER HEAT TREATMENT METHOD AND RING-SHAPED MEMBER MANUFACTURING METHOD

摘要

The ring-shaped member heat treatment method is provided with: a process of revolving a coil (21), which is disposed so as to face the rolling contact surface (11) of a ring-shaped molding (10) that is obtained from steel and which induction-heats the molding (10), relative to the molding (10) along the circumferential direction thereof to form a ring-shaped heated region in which the steel is austenitized on the molding (10); and a process of simultaneously cooling the entire heated region to the temperature of the Ms point or below. In the process for forming the heated region, each region of the rolling contact surface (11) is heated so as to alternate multiple times between a state exceeding the A1 point temperature and a temperature state below the A1 point temperature at which a supercooled austenite state is maintained.