Research Projects

Power generating units use various fuels, including oil, coal, and natural gases, with 41% of the world's power generation relying on coal. To minimize CO2 emissions, 41% of power generation relies on coal. To achieve higher efficiency and reduced emissions, advanced countries have developed ultra-supercritical (A-USC) technology, which operates at high temperatures and pressures. To handle these conditions, heat-resistant materials are needed, leading to the development of Ni-based superalloys, ferritic/martensitic steel, and austenitic grade steel. In the Indian AUSC program, Inconel 617 alloy is proposed for high-temperature sections of superheaters and reheaters, while SS304H steel is proposed for moderate high-temperature sections. A dissimilar joining of the Ni-based superalloy with heat-resistant austenitic grade SS304H steel is inevitable in a moderate high-temperature section due to economic aspects. Studying weldability issues and optimizing dissimilar welding between Inconel 617 alloy and SS304H steel is important to improve design flexibility and reduce material costs. However, welding of Inconel 617 alloy with SS304H steel faces issues due to differences in thermal expansion coefficient, melting temperature, and microstructure. This investigation includes developing a welding procedure, optimizing welding process parameters, filler selection, weldments characterization, structural integrity tests, and residual stress variation along the weldments for dissimilar welded joints of Inconel 617 alloy and SS304H steel.