Microstructure and Wear Resistance of Iron-Based Laser Cladding Layer on Surface of 35CrMo Steel

LC3530 iron-based powder was cladded on the surface of 35CrMo steel substrate by CO₂ laser cladding device. The microstructure, hardness and wear resistance of cladding layer were studied and compared with those of substrate. The results show that the microstructure of the substrate was tempered sorbite, and the grain size was about 20 μm; the microstructure of the cladding layer was uniform and fine equiaxed grains, and the grain size was mostly 8 μm. The average hardness of substrate was 254.1 HV, while that of cladding layer was 640.5 HV and the distribution of hardness was more uniform. Under the same test conditions, the wear loss and wear coefficient of the cladding layer sample were only 1/7 and 1/5 of those of the substrate, respectively; the roughness of the cladding layer sample after wear was significantly lower than that before wear, indicating that the wear resistance of 35CrMo steel was significantly improved after laser cladding. The wear mechanism of the substrate was plough wear; the wear mechanism of the cladding layer was microscopic cutting, and its excellent wear resistance was related to the formation of high hardness alloy carbides containing iron, chromium, molybdenum and carbon.