Abstract
The fatigue resistance of steel deteriorates under prolonged exposure to pressurized hydrogen due to the hydrogen embrittlement effect. The hydrogen assisted fatigue crack growth rate (HA-FCGR) is investigated in this study. A previously published tri-linear model of Region II of the HA-FCGR curve was updated to make it easier to calibrate. Fatigue test results from existing literature are used to identify fitting constants required for the updated Tri-Linear model. The modeled HA-FCGR curves are compared against experimental data to demonstrate the agreement with the test results. The updated Tri-Linear model directly correlates the hydrogen gas pressure, cyclic load ratio and frequency, test temperature, and the yield stress of the steel to the predicted HA-FCGR. The six fitting constants are transferable between steels and operational conditions, within bounds.