Determination of creep constitutive model for 28-48WCo alloy based on experimental creep tests at 817–982 °C

Abstract

The high-chromium high-nickel alloy is widely used as a heat-resistant material for components in plants under elevated temperatures, and thus, prediction of its creep deformation and rupture life is required for safe design. In this study, a creep constitutive model for the 28-48WCo alloy was determined by employing the Sherby-Dorn equation. Creep deformation tests were conducted at temperatures of 817, 871, 927 and 982 °C, under an applied stress ranging from 27.58 to 82.74 MPa. High temperature tension tests were also conducted to measure the change in elastic modulus with temperature variation. The model provided good predictability of the minimum creep strain rate in the range of experimental test conditions, with a coefficient of determination of 0.92. The creep rupture life was characterized using the Larson-Miller parameter. Creep design curves were proposed to estimate the creep rupture life of the 28-48WCo alloy at a temperature range of 817–982 °C.