激光选区熔化成型316L不锈钢工艺参数研究

针对激光选区熔化成型316L不锈钢工艺参数选择问题,采用单因素条件变量分析法,在激光选区熔化过程中,分析了激光功率、扫描速度对316L不锈钢成型零件表面粗糙度、致密度、硬度和尺寸偏差的影响规律。结果表明:当激光功率降低或者扫描速度提高时,内部能量密度减小,粉末熔化量减少,试样表面球化效应增强,孔隙缺陷增多,试样致密度减小、硬度降低;当激光功率提高或者扫描速度降低时,内部能量密度增大,粉末被过度烧蚀,产生较大的尺寸偏差,所形成熔道易塌陷,导致层间结合较差,试样性能降低。当激光功率为300 W、扫描速度为1000 mm/s时,能量密度适中,形成了较好的冶金结合,抗拉强度可达753 MPa,上表面硬度HRB能达到97.22。该项研究为316L不锈钢激光选区熔化工艺参数的合理选择提供了参考。

Study on Process Parameters of Selective Laser Melting 316L Stainless Steel

Aiming at the selection of process parameters for selective laser melting 316L stainless steel,the single factor conditional variable analysis method was used.In the process of selective laser melting,the effects of laser power and scanning speed on the surface roughness,density,hardness and dimensional deviation of 316L stainless steel parts were analyzed.The results show that when the laser power decreases or the scanning speed increases,the internal energy density decreases,the melting amount of powder decreases,the spheroidization effect of sample surface increases,the porosity defects increase,the density and hardness of the sample decrease.When the laser power increases or the scanning speed decreases,the internal energy density increases,the powder is excessively ablated,resulting in large dimensional deviation,and the formed weld channel is easy to collapse,resulting in poor interlayer bonding and reduced sample performance.When the laser power is 300 W and the scanning speed is 1000 mm/s,the energy density is moderate and a good metallurgical bonding is formed.The tensile strength can reach 753 MPa and the upper surface hardness HRB can reach 97.22.This study provides a reference for the reasonable selection of process parameters of laser selective melting 316L stainless steel.