METHOD AND HEATING COIL FOR UNIFORM HEATING OF STEP PART OF STEPPED MEMBER AND ITS NEIGHBORING PART

摘要

PURPOSE:To heat easily and uniformly the step part of a stepped member and its neighboring part with one-shot heating by heating the large-diameter parallel part and small-diameter parallel part of said member at the same heating rate by separate conductors and heating the step and its neighboring part by the heat conducted from both parallel parts. CONSTITUTION:Heating of an axially rotating work W by using heating coils is accomplished by impressing the magnetic flux phis generated from a conductor CS in the prescribed circumferential angle part to the part to be heated of the small-diameter parallel part S of said work and the magnetic flux phil generated from a conductor CL in the remaining circumferential angle part to the part to be heated of the large- diameter part L respectively at the same density per unit area and heating said parts to the same temp. within the prescribed time by impressing said magnetic fluxe respectively without deviation in the longitudinal direction of the parts to be heated. The step part sandwiched by both parts to be heated is heated to the same temp. as the temp. in the parts to be heated of the parallel parts mainly by the heat inflow from both parts to be heated and partly by the slight heat generated by the magnetic fluxes leaking from the conductors CS and CL according to the above-mentioned heating.