Effect of GTAW and GMAW-STT Processes on Mechanical Properties and Microstructure of Dissimilar Pipe Joining between ASTM A106 Gr.B and ASTM A312 TP316/316L in 6G Position

This research used an ER309LSi filler material in both 6G positions in the gas metal arc welding-surface tension transfer (GMAW-STT) process in comparison to the gas tungsten arc welding (GTAW) process. The goal of this research was to study the mechanical characteristics and microstructure of dissimilar pipe joining between ASTM A312 Gr. TP316/316L and ASTM A106 Gr.B. Tensile, bending, and Vickers hardness tests, as well as nondestructive methods, were used to test the weldment in accordance with ASME BPVC IX-2023. The experiment determined that both GMAW-STT and GTAW weldments produced non-destructive and mechanical testing results that met accepted standards. The microstructures of carbon steel are ferrite and Pearlite, stainless steel shows the presence of twin bands in the austenite matrix. It shows that the GMAW-STT process can be more productive than conventional GTAW. Furthermore, it can generate enough delta-ferrite content to prevent solidification cracking in the weld metal.