Extrapolation of creep life data for 1Cr–0.5Mo steel

A new approach to analysis of stress rupture data allows rationalization, extrapolation and interpretation of multi-batch creep life measurements reported for ferritic 1Cr–0.5Mo tube steel. Specifically, after normalizing the applied stress through the appropriate UTS value, the property sets at various creep temperatures are superimposed onto a sigmoidal ‘master curve’ using the activation energy for lattice diffusion in the alloy steel matrix (300 kJ mol−1). Despite the considerable batch-to-batch scatter, results from tests lasting less than 30,000 h then allow straightforward prediction of creep lives for stress–temperature conditions causing failure in times up to 150,000 h.