Effects of Heat Input on Microstructures, Hardness, and Residual Stress of GMA Weld Dissimilar butt joints between Stainless Steel SUS 316 and Marine Steel AH 36

Abstract

The present study investigates the dissimilar metal weld between SUS 316 and Naval Steel AH 36. The joints were fabricated with the gas metal arc welding with ER309L filler wire with two different heat inputs (0.8 kJ/mm and 1.5 kJ/mm). The weld joints were subjected to metallurgical and mechanical characterization as well as residual stress measurement by neutron diffraction several locations from the center of a weldment. The microstructural examination was carried out to reveal the defect in the weld joints and structural transformation in the weld zone. The results showed that the tensile residual stresses for the low heat input present in the axial direction and compressive residual stress in the direction of normal and transverse at stainless steels 316 welds. While the tensile residual stresses on the low heat input of marine steel AH 36 present in the direction of normal and transverse, but the compressive residual stress is in the axial direction. However, in contrast, the high heat input of dissimilar weld produces the compressive stress in the normal and transverse directions and tensile residual stress in the axial direction. The hardness value tends to proportional to the amount of residual stress. The dissimilar welds with low heat input produce a relatively higher residual stress compared to welds with high input that experienced balanced tensile and compressive residual stress.