Subsequent welding of mild steel in the pipeline industry: mechanical, wear and microstructure characteristics

Abstract In this work, an attempt was made to join MS IS2062 using a combination of gas tungsten arc welding (GTAW) and shielded metal arc welding (SMAW) processes using various welding parameters to get the best weldability. An initial scanning electron microscope study was conducted to determine the microstructure of the sample. In addition to measuring and correlating microstructures and welding parameters, mechanical properties like tensile strength and microhardness are also measured. Here, friction force (FF) and specific wear rate (SWR) were carried out to analyse the tribological behaviour of the weld joint. It was found that the weld MS IS2062 by subsequent welding achieved 15% and 5% higher yield strength and 5% and 4% harder than SMAW and GTAW. Pull-off and cracks were found in the tensile fracture image, and changes in grain boundaries have been observed in the microstructural study. The contact pressure shows the greatest influence on roughness and FF; at the same time, velocity influences the SWR, as found in the experimental results. The subsequent welding process was performed with good stabilisation by balancing between the SMAW and GTAW welding, and to obtain superior properties, we must optimise our results and choose the best possible method.