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

Fatigue crack growth thresholds ΔK_th define stress intensity factor range below which cracks will not grow. The thresholds ΔK_th 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 ΔK_th 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 ΔK_th exposed to air environment have been developed for the ASME Code Section XI. A guidance of the thresholds ΔK_th for austenitic stainless steels in air at room and high temperatures can be developed as a function of stress ratio R.