| 摘要 |
PROBLEM TO BE SOLVED: To provide a method in which inevitable bend deformation of a heating coil itself does not influence hardening quality in performing hardening of a journal part or a pin part of a crankshaft using the heating coil of a method called a semi-cut two turn method or a semi-cut two loop method.SOLUTION: Energization is performed in a state in which heating coils 13, 14 of first and second hardening units 11, 12 are abutted together to perform hardening of a work-piece W. The treatment is performed in a state in which an axial direction of oil holes 6 formed in the work-piece is aligned to a longer direction of an abutted surface of the heating coils 13, 14. An escaping concavity 38 is formed beforehand at a part facing an opening of the oil hole 6 in the heating coils 13, 14, and over heating to a vicinity of the opening of the oil hole 6 is avoided. |
