Process parameters are the key factors to ensure the quality of valve parts repaired by laser cladding.Therefore

with laser power

scanning speed

powder feeding speed and defocus amount as independent variables

and pool depth

micro hardness and dilution rate as optimization objectives

the influence of process parameters on the cladding of Fe-based alloy powder on 40Cr substrate was studied based on orthogonal experiment. The regression equations of dilution rate

depth of molten pool and micro hardness were established by stepwise regression analysis. Finally

a set of optimal process parameters were obtained by the intelligent algorithm of NSGA-Ⅱ and verified by experiments. The results show that the main factor for the dilution rate and micro hardness of the cladding layer is the powder feeding speed

and the most important factor for the depth of the molten pool is the laser power. The optimal process parameters obtained by NSGA-Ⅱare as follows: the laser power is 2 182 W

the scanning speed is 17.2 mm/s

the powder feeding speed is 18.4 g/min

and the defocusing amount is 1.86 mm. Under these parameters

the morphology of the cladding layer is greatly improved

the dilution rate is 20.3%

the depth of the molten pool is 373 μm

the micro hardness is increased by 21.7%

and the repair quality is effectively improved.