Hot Tensile Properties of Filler Added Constant Current Gas Tungsten Arc Welded AISI 304HCu Super Austenitic Stainless Steel Joints

AISI 304HCu austenitic stainless steel containing 2.3 to 3 (% wt) of Cu is mainly used in superheaters and reheater of ultra super critical (USC) boilers which operates over 600°C of steam temperature. Austenitic stainless steels welded by gas tungsten arc welding (GTAW) alters the phase composition, and microstructure of the steel in the fusion zone of welds and may affect the mechanical properties. In our previous investigation, it is found that autogenous welding of AISI 304HCu tubes resulted in segregation of alloying elements in the weld metal and resulted in joints with inferior tensile strength. Hence, in this study the high temperature tensile properties of filler added GTA welded AISI 304HCu tube joints were evaluated and correlated with the microstructural features. The tensile strength of the filler added GTA weld joints was higher than the parent metal at all test temperatures and the weld joint with filler addition was recommended for application in USC boilers.