Optimization Effects of HVOF Process Parameters on the Qualities of WC-20Cr3C2-7Ni Coating Using the Taguchi Method and Grey Relational Analysis

Taguchi is a simple and powerful analytical optimization method widely used in the design of technological processes. However, the original Taguchi method only allows for solving single-objective optimization problems. It is necessary to combine it with grey relational analysis (GRA) to achieve multiple-objective optimization. This paper presents a multi-objective optimization to study the influence of high-velocity oxy-fuel (HVOF) spray technology parameters on the quality of WC-20Cr3C2-7Ni coatings using the Taguchi method and grey relational analysis. The optimal coating process, designed by the Taguchi L9 orthogonal array, considers four factors: oxygen flow rate, LPG flow rate, spraying distance, and powder feed rate, with each factor having three levels of values. Optimal parameters were selected for the best coating quality (hardness, porosity, and deposition efficiency) from experiments. The optimal HVOF process parameters for WC-20Cr3C2-7Ni obtained by multi-objective optimization were oxygen flow rate 130 lpm, LPG flow rate 44 lpm, spray distance 310 mm, and powder feed rate 45 g.min-1.