Creep of a Carbon-Manganese Steel under Cyclic Stress and Temperature Conditions

Nearly all creep data are obtained under closely controlled constant conditions of load and temperature. Most high-temperature plant, however, is subject to cyclic variations of both, due to periodic off load or reduced load conditions.

Test data for a C-Mn steel are presented for various cycles of stress and/or temperature. The effects of cycling of stress or temperature, and of in-phase changes of both, are predictable within reasonable limits. It is shown, however, that with out-of-phase changes in stress and temperature, i.e. high stress/low temperature to low stress/high temperature conditions, a very rapid acceleration of strain can occur.