Effect of Stress Ratio on Fatigue Crack Growth Threshold for Austenitic Stainless Steels in Air Environment

摘要

The fatigue crack growth threshold ΔK_(th) is an important characteristic of crack growth assessment for the integrity of structural components. However, the accurate threshold ΔK_(th) values for austenitic stainless steels in air environment are lacking in many fitness-for-service (FFS) codes, although fatigue crack growth tests have been performed and many test data had been published. This paper focuses on fatigue crack growth threshold ΔK_(th) values for austenitic stainless steel in air environment. The paper introduces the current ΔK_(th) values provided by four major FFS codes and summarizes the available test data based on the literature survey. The paper then discusses the applicability of the existing ΔK_(th) for stainless steels and proposes a new relation as a function of the stress ratio (the R ratio) for use by FFS codes.