Microstructure and properties of selective laser melted 316Lstainless steel in different directions

doi:10.13251/j.issn.0254-6051.2020.09.030

Abstract

Abstract: Microstructure and properties in transversal and longitudinal directions of 316L stainless steel additive manufacturing specimens produced by selective laser melting(SLM) were analyzed.The results show that the substructure of the SLM additive manufacturing specimens is composed of cellular microstructure with the size of 0.4 μm,and with no obvious composition segregation.Their transversal and longitudinal tensile strengths are 808 MPa and 713 MPa,respectively.After heat treatment at 1050 ℃,some of the cellular microstructures disappear,and the transversal and longitudinal strengths are reduced to 673 MPa and 579 MPa,respectively,which still have obvious strength advantages compared with the conventional hot rolled 316L steel(550 MPa).There are unfused defects in the SLM specimens,and the directivity and geometry of the defects have significant effect on the ability of the defects joining into a crack under the action of tensile stress.The elongation of the longitudinal specimen with defect length direction parallel to the tensile direction is 47.5%,and that of the transversal specimen is 20% after heat treatment.The elongation of the SLM specimen is significantly lower than that of the hot rolled 316L steel specimen.The unfused defect is one of the main factors leading to the decrease of plastic properties of the 316L stainless steel specimens processed by SLM.

Key words: 316L stainless steel, selective laser melting, microstructure, mechanical properties

CLC Number:

TG401

Zhang Renqi, Fan Lei, Zhou Baogang, Liang Yu. Microstructure and properties of selective laser melted 316Lstainless steel in different directions[J]. Heat Treatment of Metals, 2020, 45(9): 161-166.

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