Creep-rupture life prediction for 9Cr-1Mo-Nb-V weld metal

Abstract

Creep tests were carried out with shielded-metal- Arc weld metal for 9Cr-1Mo-Nb-V steel. The testing temperature and stress levels were chosen so that rupture would occur around 1 000 hours. The three creep-rupture life prediction methodologies, namely the Monkman-Grant law, the modified projection, and the method, were applied to each experimental creep curve, and the constant numbers for individual equations were obtained. All these three were proven to be practical for weld metals similar to the base metal. However, the Monkman-Grant law has been proven to be the most effective when predicting creep rupture life at an early stage of creep test. The equation, obtained in this study, was relevant also when the Mn+Ni content varied in 9Cr-1Mo-Nb-V weld metal.