Research on multi-laser phase change hardening process on raceway surface of three-row roller slewing bearings

Three-row roller slewing bearings are the core components of large-scale rotating equipment, which play the roles of relative motion of two parts and load transfer. The laser phase change hardening numerical model and multi-lap laser phase change hardening numerical simulation of three-row roller slewing bearings were established in this paper. The hardened layer morphology under different lap rates was analyzed. Through the analysis of the hardened layer flatness, microstructure and microhardness changes in the lap area of the experimental results, the depth of the hardened layer of the specimens was more uniform in the range of 33.3%–50% lap rate. The change of friction coefficient, wear volume, and wear morphology of each group of specimens were analyzed, and the effect of different lap rates on the wear resistance of the slewing bearing raceway surface was verified. The results show that the lowest wear amount of the specimen under 2 mm lap (corresponding to 33.3% lap rate, the flatness 0.758, the softening zone width 0.74 mm) is only 0.0122 mm 3 , which reduces the wear amount by 12.5% compared with that of the base specimen, and improves the anti-wear performance. The research in this paper is conducive to improving the uniformity of the depth of the hardened layer on the surface of the three-row roller slewing bearing raceway, increasing its surface wear resistance and extending the service life of large-scale rotating equipment, which is of great engineering significance.