Sulfide Stress Corrosion Cracking of Steels

Critical nominal stress and critical stress intensity factors for sulfide stress corrosion cracking of various steels were determined using fatigue-precracked, laboratory, cantilever beam specimens and short lengths of oil field casing and tubing pressured to failure. The laboratory critical constants were found to be lower than those obtained from short lengths of casing and tubing containing longitudinal internal surface notches. Acceptable steels were defined by statistical methods as those which did not crack in sulfide environments when stressed to their yield strength. The effects of sodium chloride, pH, hydrogen sulfide concentration, temperature, cold working, heat treatment and strength of the steel on these critical constants were determined. Critical flaw sizes which can be used for inspection were calculated from the critical stress intensity factors.