Creep and High-Temperature Tensile Deformation Behavior of the TIG Welded P92/304L Dissimilar Steel Weld Joints

Abstract

Creep life, high-temperature tensile properties of creep strength enhanced ferritic-martensitic P92 steel and austenitic 304L stainless steel (SS) dissimilar weld joint were investigated. DWJ was prepared using tungsten inert gas welding process employing ERNiFeCr-2 (Inconel 718) filler metal. The creep tests were conducted at 650 degrees C under stresses ranging 80-180 MPa; and rupture times 1789.8 and 25.4 h were measured at 80 and 180 MPa, respectively. The micro-hardness investigations showed failure from base metal, P92 steel, irrespective of the creep testing condition. The early creep failure observed in P92 steel was mainly due to the formation of the laves phase and precipitation strengthening from coarsening of precipitates. The tensile and yield strengths were evaluated at temperatures ranging 450-850 degrees C to examine P92/304L weld joint strength; and strengths were found to decrease with the rise in temperature. From tensile test, it was observed that there were two types of fracture locations, which were base metals of 304L SS and P92 steel, respectively. The specimens failed from the base metal of 304L at 450 and 550 degrees C. P92 steel underwent significant strength reduction at 650 degrees C, and similar failure was also noticed in the base metal of P92 steel at 650-850 degrees C.