Creep Resistance and Microstructure Evolution in P23/P91 Welds

The paper summarizes the results of investigations on heterogeneous P23/P91 welds after long-term creep exposure at 500, 550, and 600 °C. Two weld variants were studied: Weld A used P91 steel as the filler material, while Weld B used a filler matching P23 steel. Weld A showed higher creep rupture strength than Weld B at all temperatures. Most failures in cross-weld specimens occurred in the partially decarburized zones of P23 or WM23 steel, with creep ductility below 9%. Investigations of minor phases aligned well with kinetic simulations considering a 0.1 mm fusion zone. Microstructural studies showed carburization in the P23/P91 weld fusion zones. Partial decarburization of P23/WM23 steel involved the dissolution of M7C3 and M23C6 particles, and detailed studies revealed Fe2(W,Mo) Laves phase precipitation in decarburized areas. Thermodynamic simulations linked this phase's appearance to reduced carbon content in these areas. EBSD investigations indicated better microstructural stability of partially decarburized P23 steel in Weld A based on creep test results. The dataset includes two Excel files with data from the creep tests: P91_P23_Thyssen_2024.xlsx contains data for the P91-P23 welded joint using Thyssen (Cr2WV) as the welding metal, with test temperatures of 500 °C, 550 °C, and 600 °C, stress range from 200 to 55 MPa, and time to fracture over 45,000 hours. P91_P23_Thermanit_2024.xls includes data for the P91-P23 welded joint using Thermanit E CrMo 9 B as the welding metal, with the same test parameters but a time to fracture over 81,000 hours. Both datasets are used for evaluating Seifert's parametric equation. 4o