METHOD FOR HEATING INNER SURFACE OF HOLE

摘要

PROBLEM TO BE SOLVED: To provide a method of uniformly heating the inner surface of a hole without reducing the heating efficiency in the induction heating of the inner surface of the hole. SOLUTION: In the induction heating method, the inner peripheral surface and the bottom surface of the bottomed hole arranged in a metallic member 1 is subjected to induction heating, plural hair-pin state coils 5, 5' are arranged in the holes. These coils are integrally rotated within the range of 180 deg. around the center line of the hole or electric current is supplied to the coils while changing over the bearing to uniformly raise the temp. of the inner peripheral surfaces and the bottom surfaces of the holes.