Failure Study of Creep and High-Temperature Tensile Tested Tungsten Inert Gas Welded P92 Steel and AISI 304L Steel Dissimilar Weld Joints

The present study explores the creep and high-temperature tensile performance of the P92/304L dissimilar weld joint. The gas tungsten arc welding (GTAW) technique was used to prepare the dissimilar weld joint between P92 creep strength enhanced ferritic (CSEF) steel and 304L austenitic stainless steel (SS) by utilizing ERNiCrMo-3 filler metal. After welding, tensile strength was evaluated at 450, 550, 650, 750, and 850 °C temperature to examine the performance of the dissimilar weld joint at elevated temperatures. The high-temperature tensile test result indicated that the ultimate tensile strength (UTS) decreased from 439 to 58 MPa, and yield strength (YS) fell from 155 to 41 MPa during the test from 450 to 850 °C. After high-temperature tensile strength, the creep performance of the P92/304L dissimilar weld joint has also been investigated at 650 °C in the stress range of 100-200 MPa. All the creep specimens failed from the P92 steel parent metal region during the creep test at different conditions. The maximum creep life of 706.9 h was observed for the specimen tested at 650 °C under 100 MPa. The minimum creep life of 11.9 h was observed for the specimen tested at 650 °C under 200 MPa. The relationship between the rupture time and applied stress followed the logarithmic equation as log (t r) = log (14.39695) + (− 5.79039) log (σ). The softening of the parent metal matrix due to the consumption of the solid solution strengthening W and Cr elements and the coarsening of the precipitates were the main reasons behind the creep failure at 650 °C in the stress range of 100-130 MPa. The plastic deformation caused by the grain boundary sliding was mainly responsible for creep failure at 650 °C in the stress range of 150-200 MPa. Graphical Abstract: [Figure not available: see fulltext.]