A relation between creep rate versus time is more characteristic of creep deformation behaviour than a relation between creep strain versus time, that is, a creep curve. The relation between creep rate versus time normarized by time to rupture was examined for 2.25Cr-1Mo, SUS 304 and 316 steels in order to clarify the dependences of materials and testing conditions on the creep deformation behaviour. It was found that the creep deformation behaviour was classified into four types. These four types of creep deformation behaviour were distinctly dependent on temperature and stress conditions, so a creep deformation type map was constructed for each steel. The simple expression of creep strain for each creep deformation type was proposed, and the appropriateness of these expressions was verified.
