CMT-WAAM deposition strategies for thin overhanging disc of SS308LSi and investigation of mechanical and microstructural characteristics

Abstract

This work investigates the deposition strategies with microstructural evolution and mechanical properties of SS308LSi overhanging disc produced by CMT-WAAM in horizontal position. The disc was deposited on a rotating cylindrical substrate where three primary geometrical abnormalities named sagging, start and end defect and humping were observed. The causes and remedial strategies were investigated to eliminate these abnormalities. Microstructure analysis of the layers cross section revealed a defect free layer depositions and columnar solidification with epitaxial grain growth. A very slightly coarser grains structure is observed in the middle layers of the disc compared to that of bottom and top regions. The microhardness at bottom, mid and top regions are in the range of 236 ± 9.2 HV, 227 ± 11.3 HV and 232 ± 6 HV, respectively. The microhardness values are consistent with the calculated SDAS along the build direction. Tensile tests were performed at room temperature and the samples failed with an average yield strength, ultimate tensile strength, and percentage of elongation of 391.4 ± 21 MPa, 616.8 ± 19.5 MPa and 45.6 ± 0.8% respectively. This work reveals that CMT-WAAM can successfully produce overhanging disc components of high-quality without using an industrial robot at a relatively low cost.