The present study evaluates the effect of the brine’s ionic strength upon the sulfide stress cracking resistance.

The experimental design considers the molar content of H2S in the associated gas and the NaCl concentration in the test brine as the independent variables. All tests are performed at room temperature and 1 atmosphere pressure, and the solutions are kept at constant pH of 3.5 and 4.5 through the experiments. The SSC resistance evaluation is performed on grade C110 low alloy steel by means of the notched tensile slow strain rate (NTSSRT) method to assess the value of the threshold stress intensity for SSCC (KIth).

The results indicate that at constant brine ionic strength the SSCC cracking resistance decreases monotonically with increase of the activity of dissolved H2S. Furthermore the experiments show that at constant dissolved H2S activity the KIth values increase with the brine ionic strength.

The results suggest that the dissolved H2S activity alone does not describe the relationship between the sour environment and the susceptibility to SSCC. Other parameters, such as dissolved Hydrogen in the steel must be considered.

Subject
Hydrogen sulfide, Tubular goods, Hydrogen concentration, Sour environments, Notches, Adsorption, Sodium chloride, Acidity, Constants, Fugacity, Salt concentration, Steel, Brines
Keywords:
Fracture mechanics, sulfide stress corrosion cracking, brine strength, threshold stress intensity, notch tensile tests
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2016
Association for Materials Protection and Performance (AMPP)
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