A simple model for assessing the degradation of creep rupture strength after exposure to high temperatures at low stresses

For a material such as AISI type 316 stainless steel, long-term exposure to elevated temperatures at low stresses can lead to a considerable reduction in creep rupture strength compared to the unaged or virgin material. A simple quantitative model to assess this effect on creep rupture life is proposed. The model assumes that material degradation is caused by the nucleation and growth of damaged volumes, which result in a reduction in the effective load-bearing area of the material. The model can be useful in the analysis of post-exposure testing results for remaining life assessment. © 1989.