Rationalization of Short-Term Creep Test Data and Prediction of Long-Term Creep Strengths of a Fe-20Cr-25Ni (Wt Pct) Austenitic Stainless Steel (Alloy 709)

A new creep model is applied to rationalize the stress and temperature dependences of minimum creep rate for a Fe-20Cr-25Ni (wt pct) austenitic stainless steel (Alloy 709). The creep activation energy determined on the basis of this model does not depend on stress and the stress exponent not on temperature. Consequently, it can be used together with the Mankman–Grant relationship to predict the long-term creep strengths and lifetimes at different temperatures using short-term creep rupture data.