选区激光熔化1Cr18Ni9Ti不锈钢的组织和性能

Microstructure and Properties of Selective Laser Melting1Cr18Ni9Ti Stainless Steel

为了分析选区激光熔化(SLM)成形1Cr18Ni9Ti不锈钢零件的组织和性能,研究了该零件的致密度、化学成分、微观组织和力学性能。采用1050℃/30 min工艺对拉伸试样进行固溶处理,分析了固溶处理对试样微观组织和力学性能的影响。结果表明:SLM成形1Cr18Ni9Ti不锈钢粉末时,低激光功率和高扫描速度易出现熔合不良造成的孔隙缺陷,且对试样的断后伸长率和断面收缩率的影响较大。与原始粉末相比,SLM成形零件内部S和P元素含量较少,而C元素的含量是原始粉末的2倍多。采用优化后的工艺参数成形的该零件具有良好的拉伸性能:抗拉强度为732 MPa,塑性延伸强度为576 MPa,断后伸长率为44.5%,断面收缩率Z为71%。在热处理前,内部存在一定的元素偏析,熔覆层和扫描线明显;固溶处理后,熔覆层和扫描线消失,内部组织均匀,该零件的抗拉强度为704 MPa,塑性延伸强度为384MPa,断后伸长率为40.0%,断面收缩率Z为67%。

In order to analyze the microstructure and properties of SLM 1Cr18Ni9Ti stainless steel parts,the density,chemical composition,microstructure and mechanical properties of the part were studied. The solid solution treatment for the tensile samples was carried out under 1050 ℃/30 min. The effects of solid solution treatment on the micristructure and properties of the samples were analyzed. The results show that low laser power and high scanning speed are easy to cause void defects due to poor fusion when 1Cr18Ni9Ti stainless steel powder was formed by SLM, and that has a greater impact on the elongation after fracture and the percentage reduction of area of the specimen. Compared with the original powder, the content of S and P in the SLMed part is less, while the content of C element is more than 2 times of the original powder. The SLMed part by optimizing process parameters has better tensile property, the tensile strength is 732 MPa, the plastic elongation strength is 576 MPa, the elongation after fracture is 44.5% and the percentage reduction of area Z is 71%. Before heat treatment, there is element segregation phenomenon in the interior, and the cladding layer and scanning line are obvious. After solid solution treatment, the cladding layer and scanning line disappear, and the interior structure is uniform, then the tensile strength of the part is 704 MPa, the plastic elongation strength of the part is 384 MPa, the elongation after fracture is 40.0%and the of the part is 67%.