| 摘要 |
A method and apparatus for shaping, in a planar direction, an elongatd generally flat surface formed in a steel workpiece and having a geometric continuous configuration, such as the outer facing surface of a cam on a camshaft for an internal combustion engine, which involve providing an inductor having a generally continuous heating surface matching the cam surface and generally parallel with the cam surface, forming at least one elongated uniformly cross-section groove in the inductor heating section and extending in a preselected linear location with respect to the heating surface and coterminous with the inductor heating surface, positioning the camshaft with the cam surface facing the parallel matching heating surface of the inductor with an air gap between the parallel matching surfaces so that the groove in the inductor surface faces a preselected band of the cam surface, such as the middle portion of the cam surface, energizing the inductor with a current having a frequency of less than about 25 KHz for a time less than about 3.0 seconds with a power density of about 20-70 KW/in2, at the cam surface, whereby the steel surface is heated to a temperature above the hardening temperature of the cam surface, with the higher power density at the outer edges of the cam surface, and immediately quench hardening the cam surface with a liquid quenching substance whereby the flatness of the cam surface is controlled by the position of the elongated groove. An equivalent result can be accomplished by other arrangements for changing the heating effect and particular band around the cam surface preparatory to immediate quench hardening.
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