Optimization of key technology of Inconel 718 alloy by laser additive repair

In order to further optimize the forming quality of the samples and prolong its service life, this paper explores the influence of process parameters on the forming quality and mechanical properties of Inconel 718 alloy repaired by laser cladding , and carries out the single track cladding experiment of Inconel 718 alloy by orthogonal design, observes the surface morphology of the single track cladding layers with different process parameters and measures its width and height. Through the extreme difference and ranking results, the influence law of process parameters on the geometry of single track cladding layers are analyzed, and the influence order of three main process parameters on the morphology of single track cladding layers are obtained, so as to obtain the optimal combination of process parameters. Then, the bulk Inconel 718 alloy samples without cracks, pores and other defects are successfully prepared by using the adjusted process parameters. The influence of laser power on the microstructure, hardness, tensile strength and elongation after fracture of the cladding bulk Inconel 718 alloy are studied, and the relationship between process parameters, microstructure and mechanical properties is constructed. The results show that laser power and powder feeding rate are the main factors affecting the cladding height and width respectively. When the laser power is 1600 W, the scanning speed is 12.5 mm/s, and the powder feeding rate is 8 g/min, due to the influence of temperature gradient and cooling rate, the microstructure of the cladding sample is compact, the grain size is fine, the dendrite spacing is appropriate, and The sample has excellent tensile strength and elongation after fracture.