Hydrogen effect on mechanical properties and cracking of creep-resistant 9% Cr P92 steel and P91 weld metal

Abstract Martensitic 9% Cr steels like P91 and P92 can show an increased susceptibility to delayed hydrogen-assisted cracking. The focus of this study was the microstructure heat treatment effect on mechanical properties base material multi-layer weld metal in both as-welded post treated (PWHT) condition. Tensile tests with hydrogen-free reference samples electrochemically hydrogen charged were carried out; assessed supported by detailed fractographic analysis. Finally, a microstructure-dependent fracture criterion is established. All investigated microstructures showed hydrogen-influenced degradation compared samples. martensitic had highest degree presence hydrogen. PWHT comparable properties. From that point view, significantly risk for cold cracking during welding fabrication joints must be considered before any conducted.