Fatigue propagation behaviour was investigated for low alloy steels of types commonly used in sour dilute brines. Test variables included hydrogen sulfide partial pressure, total pressure, stress ratio, fatigue frequency, steel grade and test temperature. Sour fatigue propagation rates were much higher than propagation rates in air and the sour rates
showed pronounced frequency effects at higher stress intensity factor ranges. Increased hydrogen sulfide partial pressure increased propagation but total pressure did not. Implications for operations in wet, sour environments are discussed.
Keywords: fatigue, sour brine, corrosion fatigue, fatigue crack
propagation, hydrogen sulfide, steel.