Effect of WC Content on the Wear and Corrosion Properties of Oscillating Laser-Cladding-Produced Nickel-Based Coating

Pneumatic conveying pipe is an important part of the coal industry. Its working environment is harsh, and it is mainly affected by serious wear and corrosion, which affects its operating life. Studying a method of strengthening the pipe wall of pneumatic conveying pipe is of great significance. In this paper, nickel-based alloy coatings with different WC (tungsten carbide) contents were prepared using an oscillating laser-cladding process, and the micro-characterization characteristics, wear resistance and corrosion resistance of the laser-cladded layer were discussed. The main conclusions are as follows: The microstructure of the laser-cladded layer gradually grows from the plane crystals and cellular crystals at the bottom to the relatively coarse columnar crystals in the middle, and finally to a large number of equiaxed crystals in the upper part. Moreover, with an increase in WC content, more fine equiaxed crystals are formed, mainly due to the decrease in temperature gradient with the increase in distance from the fusion line. Also, with an increase in WC content, the hardness and wear resistance of the nickel-based alloy are improved. When 20% WC is added, the laser-cladded layer shows the best corrosion resistance in 3.5 wt.% NaCl solution, and its polarization resistance is 16% lower than that when 10% WC is added. This study provides a technical reference for improving the operating life of pneumatic conveying pipelines.