The relationship between minimum creep rate and rupture time in Cr-Mo steels

The Monkman-Grant equation is widely used to relate the minimum creep rate, εmin,and the rupture time, tr, in creep. However, for materials that exhibit large tertiary creep and limited secondary creep, the above equation has not been found to be valid, and a correction in terms of the rupture strain εr and the strain at the onset of tertiary stage, ε23, has to be incorporated. The relation is given in the form. © 1992 ASM International.