SLM Process Parameters Optimization And Forming Quality Analysis Of 316L Stainless Steel

Selective Laser melting(SLM)is a metal additive manufacturing technology based on powder,which can realize the integrated manufacturing of complex parts.At present,the long manufacturing cycle caused by low forming efficiency is one of the important reasons restricting the further industrialization of this technology.In order to solve such problems,on the basis of ensuring the forming quality,this project will improve the forming efficiency of SLM products as the goal,and use 316 L stainless steel powder to optimize the forming process parameters(powder-bed depth,laser power,scanning speed,scanning distance)to achieve the expected research objectives.The specific contents are as follows.(1)refer to the original process forming equipment parameters,determine powder-bed depth?With laser power,scanning speed,scanning distance for independent variable factors,the degree of density and microhardness as evaluation index,design with three factors five levels orthogonal test,the poor analysis method to analyze the test results found that the effect of technical parameters on the dense degree of primary and secondary order: laser power>scanning distance>scanning speed;The order of influence on microhardness is laser power > scanning speed > scanning distance.(2)Combined with the multi-objective optimization method and genetic calculation solution principle,the optimization problem of process parameters under the two evaluation indexes of compacting degree and microhardness was solved,boundary conditions were set and a multi-objective optimization model was established.The regression equations of each evaluation index and process parameters were obtained by data fitting,which were used as fitness function to solve the optimization model,and the optimization parameter set was obtained.(3)Test and verify the optimized parameter set to determine the final process parameter combination.After solution heat treatment at 1050 ?,the samples prepared with these parameters were subjected to metallographic morphology analysis,tensile and impact tests,and then the parts were trial-produced.The results show that the transverse metallographic structure of the samples is closer than that of the longitudinal one.The tensile strength and impact energy of transverse specimens are greater than those of longitudinal specimens at room temperature.This parameter can be used in industrial manufacturing.The optimized process parameters were as follows: powder-bed depth 0.06 mm,laser power 330 W,scanning speed 1000mm/s and scanning spacing 0.06mm;The compactness of the prepared sample is 99.2%,the microhardness is 251.8HV,the tensile strength is [608.40,653.61]MPa,the yield strength is [319.05,386.13]MPa,the elongation is [49.25,54.85]%,the area shrinkage is [66.61,79.63]%,the impact energy is [129.74,164.13]J,Compared with the sample with original process parameters,the forming time is shortened by about 1/3,It has satisfied the expected research purpose.