Influences of the cladding method and overlapping rate on the multi-channel overlapping of composite coatings

Composite surface coatings had poor flatness rates and unmelted gaps in the multi-channel overlapping process. The mathematical prediction models of the overlapping rate, flatness rate, and defect rate were established based on the single factor test to reveal the coupling effect of the overlapping rate on the flatness and defect rates (pore area and unmelted gaps) of coatings under different cladding methods. The large flatness rate and small defect rate were optimized to obtain the optimal overlapping rate under different cladding methods based on grey correlation analysis. Finally, the cladding efficiency was used as an index to determine the optimal cladding method. The model had a certain prediction ability. The flatness rate first increased and then decreased with the increased overlapping rate; the defect rate first decreased and then increases with the increased overlapping rate. The optimal overlapping rate was obtained with 30 % circular sequence overlapping to derive maximum surface flatness and the minimum defect rate. The coating could reach 13.986 mm2, and the cladding efficiency could reach 69.930 mm3/s at this time. Results showed that the multi-index grey correlation analysis had certain feasibility for the optimization of laser cladding process parameters. The work provides references for the multi-objective optimization of the surface properties of laser cladding composites as well as a theoretical basis for the comprehensive comparison of coating performance under different cladding methods and overlapping rates.