An Estimator for the Influence of Service Temperature on Creep Rupture Life Available to Purchase

The 2001 ASME B31.1 Code (Code) has a warning to the piping designer regarding materials susceptible to creep damage. However, the Code does not prescribe a methodology to determine the accelerated life reduction for a component due to events resulting in operating temperatures in excess of the design temperature. In general, the quantitative evaluation of the service life of a component subject to creep damage is very complex. Nevertheless, the amount of accelerated creep damage due to increased temperature can be approximately estimated. This paper is the technical basis for a recent modification to the Code. It provides an approximate relationship of operating temperature and time for equivalent creep damage of typical power piping materials. Piping designers, plant operators, and plant engineers may use this information as a rough idea of the relationship of temperature and time to maintain an equivalent safety margin on creep rupture life. This evaluation includes a discussion of tolerance to temperature increase for some low chrome ferritic, intermediate chrome martensitic, and austenitic stainless steel alloys.