SYSTEM FOR MAKING DEPTH OF QUENCH HARDENED LAYER PRECISE AND UNIFORM

摘要

PURPOSE:To make the depth of a hardened layer by one-shot surface hardening precisely uniform in the stage of heating the surface of a member by induction heating by making a power source frequency constant and determining the correlation with a temp. characteristic and current conduction time shown when an output is changed. CONSTITUTION:Now if members are respectively heated by making a power source frequency constant and changing an output P in such a mode as P1>P2> P3, the characteristic curves of the temp. distribution designating the temp. at which the members can be hardened to deltamm. depth as Q0 are as follows: the outputs P1, P2, P3 in the figure provide such curves F1, F2, F3 on which the surface temps. deg.C Q1, Q2, Q3 of the members are in a relation shown by: Q1>Q2> Q3. The characteristic curves of the rising temp. which rise up to the temp. deg.Cat which the members can be hardened to the depth deltamm. provided the curves wherein the current conduction time (second) corresponding respectively to the outputs P1, P2, P3 are regulated by the inequality T1