Effect of laser surface remelting on the microstructure and properties of high manganese steel coating

In the early stage of service, high manganese steel (HMS) exhibits intensive wear, so it needs to be pre-hardened. However, the poor cutting performance of HMS limits the pre-hardening. In this paper, a two-step manufacturing technology of laser wire feeding cladding (LC) - laser surface remelting (LSR) for HMS coating was proposed, and high quality and high performance wear-resistant coating for HMS was obtained. The phase, microstructure, grain size, microhardness, and wear behavior of the coatings before and after LSR were studied. The results show that the coating obtained by LSR has better wear resistance, as the volume wear rate decreases from 2.1 x 10-4 mm3/N & sdot;m to 4.56 x 10-5 mm3/N & sdot;m, which is 78.29 % reduction. It is found that no phase transformation occurs after LSR but martensitic transformation occurs after deformation. At the same time, the grain size becomes larger, but the amount of equiaxed dendrites increases and their size decreases. These can inhibit dislocation movement and improve the work hardening capability of HMS. Through this composite process, the wear resistance of HMS under low load conditions can be greatly improved. Therefore, the improved wear resistance of HMS coating under low stress can effectively solve the initial wear problem.