Influence of Heat Inputs on Weld Profiles and Mechanical Properties of Carbon and Stainless Steel

This study examines the effect of heat input on the weld bead profile, microstructure and mechanical properties of single V- joint welded carbon and stainless-steel plates. The as-received sample steel plates were sectioned into eight pieces; dimension 75 X 30 X 10 mm  thicknesses. Shielded metal arc welding (SMAW) of heat inputs 1250 and 2030 J/mm was used to produce full penetration bead on the plates. Although visual inspection indicated that some of the welds were macro defect free, austenitic stainless steel exhibited more weld distortions than the carbon steel and this was partially attributed to its lower carbon content and the width to depth aspect ratio of the weld profile aside the magnitude of the induced stress. For the carbon steel, as the heat input increased, the hardness value of both the heat affected zone and fusion zone increased. In contrast, for stainless steel, the hardness values were reasonably comparable within same weld region (HAZ or FZ) irrespective of heat input. Furthermore, the ultimate tensile strength of the stainless steel decreased as heat input increased while the ductility increased with an increase in heat input, in contrast to carbon steel, where both ductility and ultimate tensile strength generally decreased