HEAT TREATMENT METHOD FOR MEMBER MADE OF SPHEROIDAL GRAPHITE CAST IRON

PROBLEM TO BE SOLVED: To provide a heat treatment method for a member made of spheroidal graphite cast iron in which the cost for heat treatment can be reduced by abolishing a tempering treatment and the heat treatment time can be reduced. SOLUTION: While a cooling device 13 is disposed at the inner peripheral side of a cylindrical part 14 in a case-ring gear-mounting 11 and a coil 12a for high frequency induction heating of a high frequency induction heating apparatus 12 is disposed at the outer peripheral side of the cylindrical part 14, the inner peripheral part 14b is cooled by jetting the cooling water from a jetting hole 13a of the cooling device 13 and also, the outer peripheral part 14a is heated with the high frequency induction heating apparatus 12. At this time, the high frequency induction heating is quickly performed in 11.5 sec heating time from a room temperature to 1100°C heating temperature. Then, the high frequency induction heating is finished at the time of reaching 1100°C heating temperature, and after passage of 35 sec, the cooling water is jetted from the jetting hole of the cooling device integrated with the coil 12a for high frequency induction heating, and the outer peripheral part 14a is cooled from both sides of the cylindrical part 14. COPYRIGHT: (C)2005,JPO&NCIPI