Microstructure and wear resistance of Ni-based tungsten carbide coating by laser cladding on tunnel boring machine cutter ring

Tunnel boring machine (TBM) cutter is the tooth of TBM, the service life of the cutter affects the construction progress and efficiency. In this study, the Ni-based tungsten carbide composite powder was deposited on the surface of the TBM cutter ring by laser cladding to improve the wear resistance. The microstructure of the coating was analyzed, the wear resistance was studied and compared with the substrate. A wear-resistant coating with low porosity was prepared on the surface of the 5Cr5MoSiV1 cutter ring, which has a good metallurgical bonding with the substrate. The main phases in the coating were γ-Ni, WC and W2C. Spherical WC and its decomposed WC and W2C small particles are widely distributed in the coating, effectively hindering the pressing and ploughing of hard rock particles, thereby improving the wear resistance of the coating. The calculated results of the volume loss before and after wear showed that the wear resistance of the cladding layer was about 7 times higher than that of the substrate. The results showed that laser cladding Ni-based WC is effective ways to improve the tribological properties of TBM cutter ring.