Hot Tensile Properties of Shielded Metal Arc Welded Similar and Dissimilar Joint of 9Cr-1Mo Steel and 304 Stainless Steel

The recent demand for power generation capability has raised the operating temperature of the power plants in the range of 600°C. High operating temperature leads to material degradation or reduced lifespan of boilers, which necessitates the analysis of the high-temperature behavior of welded joints of power plant boilers for a long lifespan and improved efficiency. Gr91 martensitic and SS304 austenitic stainless steel are identified as the primary piping material for these boilers. The boiler piping involves similar weld joints (Gr91/Gr91 and SS304/SS304) and dissimilar weld joints (SS304/Gr91) known as transition joints. These joints are exposed to high temperatures for a long duration during their service and it is therefore necessary to evaluate the high-temperature behavior of these weld joints. The hot tensile test is a short-term high-temperature test that serves as a valuable tool for analyzing the high-temperature behavior of the welds. In this investigation, by using the shielded metal arc welding (SMAW) process, similar joints of Gr91/Gr91 martensitic steel, SS304/SS304 were made using matching electrodes, and dissimilar joints between Gr91/SS304 were welded using INCONEL electrode. The joints were subjected to hot tensile test at temperatures of 550°C, 600°C, and 650°C. The stress–strain behavior of the weld joints at elevated temperatures was studied, compared with each other, and reported.