Analysis of Surface Defects of Spiral Bevel Gear for Automobile Rear Axle

The spiral bevel gear of automobile rear axle was found to have many micro-hole defects in the tooth grinding process after carburizing and quenching heat treatment. Optical microscopy, scanning electron microscopy and a direct reading spectrometer were used to analyze the small-hole defects on the tooth surface. The results show that the small-hole defects on the tooth surface of the gear are due to the small-hole defects in the whole ring area of the radial section of the gear ring, which were exposed outside after the milling teeth. The small-hole defects in the whole ring region of the radial section of the gear were caused by deformation over-burning of the gear ring during the rolling process. In order to prevent such failure, it is advised that the temperature control should be strengthened and the rolling process should be optimized. In addition, ultrasonic inspection should be carried out after the turning process of the gear ring.