体能量密度对SLM成形316L不锈钢耐腐蚀性的影响

Influence of bulk energy density on corrosion resistance of 316L stainless steel formed by SLM

为了探究不同体能量密度对SLM成形316L不锈钢耐腐蚀性的影响,采用正交试验法制备不同激光功率、扫描间距和扫描速度下的SLM 316L不锈钢成形件,利用扫描电镜和电化学试验对其微观组织和自腐蚀电位进行观察和测量。结果表明,体能量密度过大或过小时,成形件表面的气孔和孔洞等缺陷较多,自腐蚀电位减小,耐腐蚀性变差。体能量密度为44.64 J/mm^(-3)时,SLM 316L不锈钢成形件的自腐蚀电位最高,组织表面的气孔等缺陷相对较少,耐腐蚀性最好。激光功率、扫描间距和扫描速度对SLM 316L不锈钢成形件的耐腐蚀性影响的次序为:激光功率>扫描间距和扫描速度,最佳的工艺参数组合为激光功率250 W,扫描间距0.14 mm,扫描速度800 mm/s。

In order to explore the effect of different bulk energy density on corrosion resistance of SLM formed 316 L stainless steel, SLM 316 L stainless steel formed parts were prepared under different laser power, scanning spacing and scanning speed by orthogonal test method. The microstructure and self-corrosion potential were observed and measured by means of scanning electron microscope and electrochemical test. The results show that if the bulk energy density is too large or very small, there are more defects such as pores and holes on the surface of the molded parts, the self-corrosion potential is decreased, and the corrosion resistance is deteriorated. When the bulk energy density is 44.64 J/mm^(-3), the self-corrosion potential of SLM 316 L stainless steel molded parts is the highest, the defects such as pores on the surface are relatively few, and the corrosion resistance is the best. The order of the factor of laser power, scanning distance and scanning speed on the corrosion resistance of SLM 316 L stainless steel molded parts is: laser power > scanning distance and scanning speed. The best combination of process parameters is laser power of 250 W, scanning spacing of 0.14 mm and scanning speed of 800 mm/s.