Cause Analysis on Turning Hard Point of 40Cr Steel Bearing Retainer Ring

When a bearing company produced the 40Cr steel bearing retainer ring, it was found that there were turning hard points in the 40Cr steel bearing retainer ring. The causes of turning hard points were analyzed by means of chemical composition analysis, hardness test, metallographic examination. The results show that the turning hard points of the 40Cr steel bearing retainer ring were caused by the pressing of dissimilar metals. It should be that during the rolling process of steel, the parts of the production line were not fastened well, and they were impacted by the external force during the rolling process, which made the parts fall off. The parts were pressed into the steel in a moment during the high-speed rolling process, which finally caused the turning hard points of the bearing retainer ring.