Predicting the Strain to Tertiary Creep for Elevated-Temperature Structural Materials

Abstract

The creep strain incurred before the onset of tertiary creep can be an important design criterion in the use of elevated-temperature structural materials. Various methods for predicting the amount of this strain are discussed. Application of these methods to data for types 304 and 316 austenitic stainless steels, nickel-base Inconel alloy 718, and ferritic 2 1/4 Cr-1 Mo steel is presented, with generally good results. The behavior of these four materials, including variations among different materials, is discussed in terms of basic material characteristics.