Study on Microstructure and Properties of 50CrMo4 Steel Treated by Laser Texture-Discrete Hardening

In order to explore the influence of surface texture on laser discrete hardening effect, the surface of 50CrMo4 steel with different texture parameters was treated by laser discrete hardening.The size, microstructure, phase and hardness of hardened spot were analyzed by optical microscope, scanning electron microscope, X-ray diffractometer and microhardness tester.The results show that the laser beam can diffuse reflect inside the texture to promote the secondary absorption of the laser beam, which can improve the absorption rate of the laser beam, and the diameter and depth of the hardened spot are increased by 8.5% and 22.7%, respectively, compared with the un-textured surface.The hardened area increases with the increase of texture depth and density, and the influence of texture density is more obvious.The finer martensite structure of the hardened layer on the texture surface increases the average hardness of the hardened area by 4.3%.