INDUCTION HARDENING METHOD FOR CRANK SHAFT AND APPARATUS THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide an induction hardening method for crank shaft and an apparatus therefor with which the hardening treatment of the crank shaft can be performed in a short time and the efficiency of the hardening treatment of the crank shaft can be improved. SOLUTION: During applying the hardening-cooling process for performing hardening and cooling by injecting the cooling liquid for hardening to pin parts 3a-3d after applying the high frequency induction heating to the pin parts 3a-3d of the crank shaft 1, the hardening treatment process is applied to a flange part F at the one end side of the crank shaft 1 or a shaft part S at the other end side of the crank shaft 1.