过配粉末激光选区熔化制备高氮不锈钢研究  

Manufacturing of high nitrogen stainless steel by Selective Laser Melting with overmixed powders

作　　者：任建彪 赵定国 孙鑫 王书桓 倪国龙 柳昆 REN Jianbiao;ZHAO Dingguo;SUN Xin;WANG Shuhuan;NI Guolong;LIU Kun(School of Metallurgy and Energy,North China University of Science and Technology,Tangshan 063210,China)

机构地区：[1]华北理工大学冶金与能源学院,河北唐山063210

出　　处：《粉末冶金工业》2023年第3期13-22,共10页Powder Metallurgy Industry

基　　金：河北省自然科学基金资助项目(E2020209014、E2021209146);河北省教育厅科研项目(JYG2021004)。

摘　　要：常压下高氮不锈钢粉末激光选区熔化法制备高氮不锈钢的过程存在氮逸出现象,不能有效制备出合格高氮不锈钢。采用过配粉末法配制了含氮量1.472%的不锈钢粉末,在激光选区熔化设备上开展了过配粉末打印成形实验,研究了激光工艺参数对高氮不锈钢氮含量、显微组织和力学性能的影响。实验结果表明,过配粉末法可制备出含氮量超0.9%且具有一定力学性能的高氮不锈钢;成形试样的氮含量与激光功率成反比,在扫描速度为1000 mm/s时,激光功率由200 W增至300 W,氮含量由0.991%降至0.956%;当激光功率为225 W时,扫描速度由700 mm/s增至1000 mm/s,氮含量由0.823%增至0.985%,与扫描速度成正比;当激光功率为250 W时,扫描速度由700 mm/s增至1000 mm/s,氮含量由0.817%增至0.970%,扫描速度对氮含量的影响更为显著。当扫描速度为1000 mm/s时,200~300 W范围内,随激光功率的增大,成形试样的内部缺陷逐渐减少,成形质量变好,抗拉强度呈先增加后降低趋势。优化结果表明,扫描速度1000 mm/s、激光功率275 W为最优成形工艺参数,在保证氮含量高于0.9%的同时,高氮不锈钢成形质量最好,内部缺陷数量最少,综合拉伸性能好,抗拉强度和屈服强度分别为1001.7 MPa和363.8 MPa。Nitrogen evolution exists in the process of Selective Laser Melting of high nitrogen stainless steel powder under atmospheric pressure,and qualified high nitrogen stainless steel cannot be effectively made.Stainless steel powder with nitrogen content of 1.472%was prepared by overmixing powder method,and the printing forming experiment of overmixed powders were carried out on Selective Laser Melting equipment.The effect of laser processing parameters on the nitrogen content,microstructure and mechanical properties of high nitrogen stainless steel was studied.The experimental results show that high nitrogen stainless steel with more than 0.9%nitrogen content and certain mechanical properties can be prepared by overmixed powders method.The nitrogen content of the formed sample is inversely proportional to the laser power,at a scan speed of 10oo mm/s,laser power is increased from 200 W to 300 W,nitrogen content decreases from 0.991%to 0.956%.Being directly proportional to the scan speed,at 225 W laser power,Scan speed is increased from 700 mm/s to 1000 mm/s,nitrogen content increases from 0.823%to 0.985%.At 250 W laser power,Scan speed is increased from 700 mm/s to 1000 mm/s,nitrogen content is increased from 0.817%to 0.970%.The scanning speed has more significant effects on the nitrogen content.At a scan speed of 1000 mm/s,ranging from 200 to 300 W,with the increase of laser power,the internal defects of the sample gradually reduce,the forming quality becomes better,and the tensile strength increases first and then decreases.The optimization results show that the scanning speed of 1000 mm/s and laser power of 275 W are the optimal parameters.The forming quality of high nitrogen stainless steel is the best,the number of internal defects is the least,and the comprehensive tensile properties are good,the tensile strength and yield strength are 1001.7 MPa and 363.8 MPa,respectively,while the nitrogen content is higher than 0.9%.

关 键 词：过配粉末 激光选区熔化 高氮不锈钢 氮含量 力学性能 

分 类 号：TF764.1[冶金工程—钢铁冶金]