Microstructural and mechanical characteristics of 308L stainless steel manufactured by gas metal arc welding-based additive manufacturing

Abstract

In this paper, gas metal arc welding-based additive manufacturing (GMAW-AM) was used to build thin-walled 308L stainless steel parts. The microstructural and mechanical characteristics of the built thin walls were investigated. The results show that the GMAW-AM thin-walled 308L is dominantly composed of columnar dendrites, which grow along the build direction when increasing the number of depositing layers. The microstructure of the GMAW-AM thin-walled 308L mainly consists of two phases: a small amount of δ ferrite phases displayed within γ austenite dendrites. The microhardness of built materials ranges from 155 ± 1.20 HV0.1 to 169 ± 5.67 HV0.1. The average ultimate tensile strength (UTS), yield strength (YS) and elongation (EL) of the GMAW-AM thin-walled 308L in the vertical direction are 531.78 ± 4.52 MPa, 343.67 ± 7.53 MPa, and 39.58 ± 1.38%, respectively, which are obviously lower than those in the horizontal direction (UTS: 552.95 ± 4.96 MPa, YS: 352.69 ± 8.12 MPa, and EL: 54.13 ± 1.29%).