Fig. 12: Comparison of the pH2S limit derived from BN backward analyses against experimental evidence from the literature. | npj Materials Degradation

Fig. 12: Comparison of the pH2S limit derived from BN backward analyses against experimental evidence from the literature.

From: Predicting stress corrosion cracking in downhole environments: a Bayesian network approach for duplex stainless steels

Fig. 12

a Pitting corrosion instances occur as pH2S approximates to 0.5 bar. b SCC instances are primarily seen above 0.5 bar pH2S. Symbol shape indicates material type: circles for conventional DSS and diamonds for super DSS. Data points are coloured red if pitting, or SCC was reported and blue if no corrosion damage occurred. The black dashed lines in both plots represent the safe operating limits for pH2S (i.e., 0.02 and 0.2 bar) for DSS alloys according to ISO 15156-3 standard31. In contrast, the limit derived from the BN model at 0.5 bar pH2S is highlighted in pink. The data points cover a wide range of experimental conditions: pH2S up to 1.0 bar, Cl− concentrations near 30,000 ppm, temperatures from 21 to 100 °C; a pH interval of 2.5–5.4, pCO2 up to 70 bar, and applied stresses closely to \({\sigma }_{R}\) ≈ 0.9.

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