Process Optimization for Cold Metal Transition Cladding 316L Stainless Steel on Q235B Steel Surface

316L stainless steel cladding layer was prepared on the surface of Q235 steel by cold metal transition （CMT） cladding technique. Through the design of a three-factor and three-level orthogonal test, the effects of wire feeding speed （5.0, 5.5, 6.0 m·min⁻¹）, welding speed （2.0, 2.5, 3.0 mm·s⁻¹） and swing width （12, 14, 16 mm） on the microstructure, microhardness, dilution rate, wear resistance and corrosion resistance of the cladding layer were systematically studied, and the optimal cladding process was obtained. The results show that the cladding layer prepared by different processes all formed good metallurgical bond with the substrate. The bottom of the cladding layers was composed of columnar crystals, a small amount of equiaxed crystals and dendritic crystals, while the top was mainly composed of equiaxed crystals and a small number of columnar crystals. The average hardness of the cladding layer under different processes was 246.3 HV, approximately 1.54 times that of the substrate. The average friction coefficient and the average wear mass loss were 0.302 5 and 3.82 mg, respectively, both lower than those of the substrate （0.392 4, 6.5 mg）. The order of influence of CMT cladding process parameters on the quality of the cladding layer from high to low was wire feeding speed, welding speed, and swing width. The optimal process parameters were wire feeding speed of 6.0 m·min⁻¹, welding speed of 3.0 mm·s⁻¹, and swing width of 14 mm. At this time, the hardness of the cladding layer was the highest, at 259.8 HV, the free-corrosion current density was relatively low, at 0.132 6 mA·cm⁻², the wear mass loss was 3.3 mg, and the dilution rate was 9.80%.