Experimental characteristics of 316L stainless steel thin wall processed in wire-based arc additive manufacturing process

Abstract

Wire arc additive manufacturing (WAAM) is an innovative technology for the fabrication of larger metal parts with complex geometry. It has a higher deposition rate, low wastage, production efficiency, and close tolerance. In this work, 316L stainless steel parts were manufactured by cold metal transfer-based WAAM process, and the effects of microstructure and mechanical properties were investigated. Microstructure studies reveal the formation of columnar and equiaxed grain morphologies with the development of epitaxial growth along the building direction. The radiographic test confirms various defects such as pores and cracks associated with the 316L deposited part. However, the microhardness studies show a uniform distribution of hardness values. The average value of microhardness of the as-deposited part was 220 HV. Tensile studies show the horizontal samples were ultimate tensile stress (UTS): 576 MPa, yield stress (YS): 302 MPa, and elongation (EL): 35% in comparison with the vertical samples were UTS: 469 MPa, YS: 295 MPa and EL: 39% and the sample exhibits the anisotropy properties. Further, the fracture surface of the tensile sample exhibits a ductile fracture with enough dimples, voids, and plastic deformation. The result shows that fabricated WAAM stainless steel 316L parts exhibit the finer microstructure and improved mechanical properties, which is extremely better than 316L stainless steel casting, forging, and wrought counterparts.