工艺参数对SLM成型316L不锈钢致密度的影响及缺陷表现方式

Effect of Process Parameters on Density of 316L Stainless Steel by SLM and Defects Manifestation Methods

利用选区熔化成型技术(SLM)制备了316L不锈钢试样。通过正交实验法研究了工艺参数对试样致密度的影响,利用扫描电镜(SEM)观察了试样组织缺陷,最后用金相显微镜观察试样表面的组织结构,同时验证试样的致密度。结果表明,工艺参数对试样致密度的影响顺序从大到小依次为:扫描间距、激光功率、扫描速度。体能量密度在小于52.33 J/mm^(3)时,致密度随着体能量密度增大而增大;体能量密度在大于52.33 J/mm^(3)时,致密度变化不明显,维持在94.09%~95.91%。由扫描间距过低造成的体能量密度过低会使试样表面出现行列式分布的孔洞,在一定范围内调高激光功率和调低扫描速度能有效减缓孔洞数量。试样组织相为单项奥氏体,试样致密度越大,孔洞越少。

316L stainless steel samples were prepared by selective laser melting(SLM). The effects of process parameters on the density of samples were investigated by orthogonal test. The structure defects of samples was observed by SEM. Finally, the microstructure of the sample surface was observed by metallographic microscope, and the densification of the sample was verified. The results show that the order of influence of process parameters on the density of samples from large to small is: scanning distance, laser power and scanning speed. When the bulk energy density is less than 52.33 J/mm^(3),the density increases with the increase of the bulk energy density. When the bulk energy density is greater than 52.33 J/mm^(3),the density does not change significantly, and maintains within 94.09%-95.91%. The low bulk energy density caused by too low scanning spacing induce the determinant distribution of voids on the surface of the sample, and in a certain standard,adjusting laser power and scanning speed can effectively reduce the number of holes. The microstructure of the sample is single austenite. The higher the density of the sample, the less the holes.