Dissimilar autogenous TIG joint of Alloy 617 and AISI 304H steel for AUSC application

To reduce costs and improve high-temperature performance in Advanced Ultra Super Critical (AUSC) boilers, it is necessary to weld austenitic steel Inconel alloy. In this study, the autogenous tungsten inert gas (TIG) welding process was used join Alloy 617 an AISI 304H plate of thickness 5 mm. Microstructural analysis showed that microstructure formation uneven along weldments, with columnar cellular dendrites near interface while central area exhibited a combination columnar, cellular, equiaxed dendrites. The use energy dispersive spectroscopy electron probe micro-analysis unveiled presence unmixed layer at between steel. Furthermore, notable variation concentration alloying elements such as Fe, Cr, Ni, Co, Mo observed. Within metal, inter-dendritic areas precipitates rich Ti, Mo. Meanwhile, heat-affected zone (HAZ) phases like Cr Mo-rich M23C6 well M6C. Hardness tests non-uniform hardness 199 ± 6 HV metal 225 4 HAZ, 207 7 HAZ. segregation spaces led decline tensile properties welded parts resulted failure from region metal.