Development of Fatigue Crack Growth Thresholds for Austenitic Stainless Steels Exposed to Air Environment for ASME Code Section XI

Fatigue crack growth thresholds Delta Kth define stress intensity factor range below which cracks will not grow. The thresholds Delta Kth are useful in industries to determine durability lifetime. Although massive fatigue crack growth experiments for stainless steels in air environment had been reported, the thresholds Delta Kth are not codified at the American Society of Mechanical Engineers (ASME) Code Section XI, as well as other fitness-for-service (FFS) codes and standards. Based on the investigation of a few FFS codes and review of literature survey of experimental data, the thresholds Delta Kth exposed to air environment have been developed for the ASME Code Section XI. A guidance of the thresholds Delta Kth for austenitic stainless steels in air at room and high temperatures can be developed as a function of stress ratio R.