Effects of Laser Remelting on Microstructure, Wear Resistance, and Impact Resistance of Laser-Clad Inconel625-Ni/WC Composite Coating on Cr12MoV Steel

In this study, an Inconel625-Ni60-Ni60/25%WC (Inconel625-Ni/WC) composite coating was fabricated on Cr12MoV steel by first-stage laser cladding, followed by second-stage laser remelting with various laser powers, and the better laser energy density of 25.0 J/mm2 for laser remelting test was obtained by macroscopic morphology and microhardness analysis. The effects of laser remelting on the microstructure, microhardness, wear resistance, and impact resistance of the composite coating was systematically investigated by combining various characterization methods. The results showed that laser remelting did not cause the composite coating to produce new phases. The microstructure of the Ni/WC layer in the remelted composite coating was denser and finer, and the average grain size of the surface layer was reduced by 11.69%. The impact depth of laser remelting was about 2.0 mm. The average microhardness of the Ni/WC layer in the remelted composite coating increased by 5.9%, and the average wear rate of the surface was reduced by 50.12% compared with that before laser remelting. The wear surface of remelted composite coating exhibited abrasive wear, and the wear resistance was significantly improved. In addition, the impact toughness value of the remelted composite coating reached 5.15 J/cm2, which increased by 87.96% compared with that before laser remelting. The impact resistance of the composite coating was further improved.