METHOD AND DEVICE OF LOCAL ANNEALING BY HIGH FREQUENCY INDUCTION HEATING

PURPOSE:To prevent welding deformation by winding a ceramic member of good heat conductivity on the surface of a columnar member, by providing an iron core material in such a way that the surface of the ceramic member is covered therewith, and by winding an excitation coil thereon, so as to let high frequency current run. CONSTITUTION:A ceramic material 5 of an insulator of good heat conductivity is wound on the outer surface of a turbine rotor shaft 1, in an layer, and the end shape of an iron core 6 of a conductor is provided on the outer surface thereof in such a way that a magnetic line of force 2 is concentrated on a heat affecting part (HAZ part) 12, and a high frequency heating coil 3 is wound on the outer surface of the iron core 6, while high frequency predetermined current and voltage are supplied from a high frequency heating power source 4, so as to heat only the HAZ part 12. Since only a predetermined point can be heated effectively, deformation due to heat treatment can be eliminated.