MICROSTRUCTURE AND FRACTURE MECHANISM OF WIRE ARC 316L STAINLESS STEEL WELDED JOINTS

Hang Dong; Yong Wang; Zhiyuan Liu; Can Liu

doi:10.17222/mit.2026.1640

Hang Dong School of Mechanical Science and Engineering, Northeast Petroleum University, 199 Fazhan Road, Daqing 163318, China
Yong Wang School of Mechanical Science and Engineering, Northeast Petroleum University, 199 Fazhan Road, Daqing 163318, China
Zhiyuan Liu School of Mechanical Science and Engineering, Northeast Petroleum University, 199 Fazhan Road, Daqing 163318, China
Can Liu School of Mechanical Science and Engineering, Northeast Petroleum University, 199 Fazhan Road, Daqing 163318, China

DOI: https://doi.org/10.17222/mit.2026.1640

Keywords: WAAM, welding, mechanical properties, microstructure

Abstract

This study investigates TIG-welded joints of wire arc additively manufactured 316L stainless steel. A pronounced <001> texture occurred in the fusion zone, with the strongest texture intensity observed in the columnar dendritic region, while the fusion zone center consisted of equiaxed grains with random orientations. The heat-affected zone exhibited a significant ‘thermo-mechanical’ effect, with high-angle grain boundaries decreasing from 91 % to 56 %. Non-uniform microhardness was observed, with the minimum in the columnar dendritic zone. The joint achieved an ultimate tensile strength of 378.6 MPa. However, the dimples on the fracture surface were predominantly shallow and heterogeneously distributed, indicating constrained ductility despite the ductile fracture mode.

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