| 摘要 |
<p>PURPOSE:To enable hardening imparting uniform hardness and generating no quenching crack, in applying high frequency hardening to the end surfaces of machine parts having different radii around the axial line thereof, by a method wherein ring like grooves are formed to the end surfaces of machine parts and high frequency hardening is applied to the inner side surfaces thereof. CONSTITUTION:Ring like grooves 3 are provided to both end surfaces 2 of the clutch hub for an automobile having each different dimensions such as (a), (b), (c), (d) or (e) and, in this state, high frequency coils are arranged so as to be opposed to respective end surfaces 2 to heat the same and, when the temps. of the inner surfaces of the ring like grooves in the end surfaces 2 reach 850- 900 deg.C, oil hardening is carried out. Because uniform temp. distribution can be assured over the inner surfaces of the ring like grooves 3 during high frequency heating by said ring like grooves, uniform hardness distribution is obtained over the total inner side surfaces after hardening as well as the hardening free from quenching crack or dimensional change.</p> |
