Multi-objective optimization of laser cladding parameters based on PCA and RSM-DE algorithm

The Box-Benhnken Design (BBD) experimental design model, as one of the response surface methods, was designed to obtain the optimal parameters for laser cladding of Inconel 718 powder on Q690 high-strength steel plate. A mathematical model between input variables (laser power, scanning speed, powder delivery rate) and response values (dilution rate, heat affected zone depth, microhardness) was established. Principal component analysis method was used to establish the comprehensive evaluation index of cladding layer, and differential evolution algorithm was used to optimize and determine the optimal process parameters. The optimal process parameters were used for test verification, and the macro-morphology and microstructure of the specimen under the optimal process parameters were observed and analyzed, and the response values were compared with the optimized specimen. The results showed that the optimal processing parameters were laser power of 1 800 W, scanning speed of 28 mm/s, and powder feeding rate of 1.9 r/min, under which the heat affected zone depth was 294 μm, the dilution rate was 14.2%, and the microhardness was 276.6 HV0.5. The optimum specimens showed a 6.8% reduction in the depth of the heat affected zone, a 24.7% reduction in dilution, and a 21.7% increase in microhardness, and the optimum specimens showed small dendritic crystals with a small amount of cellular crystals.