Effect of Laser Remelting of 65Mn Steel on Microstructure Distribution and Tribological Properties

The brick-mud bionic microstructure of 65Mn steel was generated using a laser surface remelting method with different laser scanning speeds. The microstructure distribution, microhardness profile, and tribological properties were studied. The results indicated that the formed microstructure of the laser-treated samples displayed a crescent macromorphology. The top remelted zone was composed of martensite and retained austenite. The heat-affected zone was constructed with martensite and a few carbides. The formed martensite and retained austenite constructed the hard-phase (brick) and soft-phase (mud) bionic units, respectively. The maximum microhardness of the remelted zone and transition zone reached approximately 837 and 750 HV, respectively. The tribological results showed that the surface of the laser-remelted 65Mn steel exhibited prospective wear resistance. The average wear depth of the laser-treated bionic surface was reduced by 33% compared with that of the untreated surface. This is consistent with the qualitative simulation of the Johnson–Cook intrinsic structure model.