选择低成本的316L不锈钢旧粉进行选区激光熔化（SLM）成形,拟通过工艺参数优化和热处理来提高产品的性能。采用平均粒径为27.6 μm的316L不锈钢旧粉,在不同的工艺参数下制备多组试样,然后进行微观形貌观察和力学性能测试;选取成形性能较优的试样,研究不同冷却方式的热处理工艺对试样力学性能、耐蚀性以及组成相的影响。研究结果表明：激光能量密度为54 J/mm 3时,试样的成形性能（硬度、抗拉强度、延伸率等）最佳,且激光能量密度一定时,成形性能与激光功率、扫描速度密切相关;热处理后,试样表现为硬度和抗拉强度下降,延伸率和耐蚀性增大,奥氏体组织未发生转变,仅晶粒尺寸变大。使用316L不锈钢旧粉进行SLM成形时,选择适宜的成形参数与热处理方法可以使成形件具有优良的力学性能。

In this paper, the used powder of 316L stainless steel with low cost was selected for selective laser melting （SLM）, and process parameter optimization and post-heat treatment were performed to improve the properties of the products. To be specific, after multiple groups of samples were prepared under different process parameters through the used powder with an average particle size of 27.6 μm, their microstructures were observed and their mechanical properties were tested. Then, some samples with good forming properties were adopted to study the effect of the heat treatment process with different cooling modes on the mechanical properties, corrosion resistance, and phase composition. The results show that when the laser energy density was 54 J/mm 3, the forming properties （hardness, tensile strength, elongation, etc.） of the samples were optimal, and the forming properties of the samples were closely related to the laser power and scanning speed in the case of constant laser energy density. After heat treatment, the hardness and tensile strength of the samples decreased, and the elongation and corrosion resistance improved. Besides, the austenite structure was not transformed, and only the grain size became larger. In conclusion, when the used powder of 316L stainless steel was employed for SLM, selecting reasonable forming parameters and heat treatment method can achieve good mechanical performance of the products.