Processing flow of bevel gear: blanking → finishing → grinding → carburizing and quenching → cleaning → tempering. Later, it was found that the surface of the bevel gear showed a large arc peripheral arc crack. 1 / 3 of the cracks of the bevel gear sample were located on the upper convex plane of the bevel gear, and about 2 / 3 were located on the outer arc surface. From the appearance, there were two breaks about 100 ° adjacent to the outer arc peripheral surface, and the overall grain was straight, showing the characteristics of quenching stress crack.
The crack depth of the crack section is about 30mm inward from 17mm from the surface and 45mm from the surface, that is, before the stress causes the crack, the aggregation degree is uniform in the appearance of the finished bevel gear, and the release is completed instantly. The macro morphology of cracked bevel gear is shown in the figure.