| 摘要 |
A cam shaft manufacturing process wherein a cam shaft is cast from a heat-treatable gray cast iron having a high carbide microstructure, is annealed while retaining the carbides and then cooled to room temperature. Surfaces, such as cam lobe surfaces, are then surface hardened and the cam shaft may thereafter be machined. The heat treating process comprises heating the cam shaft at 1600 DEG F. (871 DEG C.) in about twenty minutes, holding the cam shaft at 1600 DEG F. (871 DEG C.) for about twenty minutes and thereafter heat treating the cam shafts at a temperature of 1600 DEG to 1640 DEG F. (871 DEG to 893 DEG C.) for about eighty minutes. The cam shafts are then cooled rapidly to about 400 DEG F. (204 DEG C.), for example, within about an hour and a half, and thereafter air cooled.
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