Evaluating the Effects of Gas Tungsten Arc Weld Parameters on Mechanical Properties of UNS S31803 Stainless Steel Weldment

The focus of this study was to evaluate the weld parameters in relation to heat input and their effect on corrosion and mechanical properties. Such properties include hardness, tensile strength and impact toughness of UNS S31803 stainless steel. Using the process of Gas Tungsten Arc Weld, samples of 50.8mm (2inch) UNS S31803 stainless steel pipe with dimensions of thickness 5.54mm and 300mm length were welded. The range of parameters in which the weld was carried out are voltage of 10- 12V, speed of weld 50 90mm/min, and weld current 100-150A. To ensure no defects, samples were first tested non-destructively after welding and micro-structural examinations and ferrite content measurements were performed. Corrosion test, according to ASTM G48 standard, was conducted. The heat input effect on hardness, tensile, and impact toughness was also examined. The effects of the parameters were studied from the experiment results. It was observed that there were improved mechanical properties at low heat input than high heat input. The Corrosion rate for optimized parameters at 22oC and 28oC were 0.04g/m2.day, and 0.74g/m2.day respectively, which is lower than the 1.00g/m2.day in which corrosion is said to be initiated. The optimum welding parameters of the experiment were found to be welding current of 100A, voltage of 10V, and speed of 90mm/min. The hardness, tensile strength and impact toughness values for the optimized parameters after conducting a confirmation experiment were found to be 371HVN, 994MPa, and 237J respectively. The study showed that weldment has higher strength values than the base metal