| 摘要 |
<p>PURPOSE:To minimize the remaining soft part by stopping the supply of an electric current when a heating coil reaches the hardened part in the hardening of the circumferential part of an annular member, etc. with an induction heating coil and a follow-up cooler, and cooling the member below the coil by sprayed water. CONSTITUTION:The hardening of an annular member W is carried out with a high-frequency heating coil C directly above the part to be hardened and an attached cooler J, and the heated part is quenched by moving the coil C. In hardening the circumferential surface, when the heating coil C reaches the already hardened part H1, the supply of the current to the coil is stopped. The cooling water SJ is simultaneously sprayed to the surface of a member below the coil C which is hardened. Although a large remaining soft zone is left heretofore to eliminate the inconveniences due to the reheating of the already hardened part H1, the remaining soft zone can be exremely narrowed by this method.</p> |
