Stress corrosion cracking of X80 pipeline steel exposed to high pH solutions with different concentrations of bicarbonate

• Published in: International journal of minerals, metallurgy and materials metallurgy and materials, 2013-07, Vol.20 (7), p.645-652
• Main Authors: Fan, Lin, Du, Cui-wei, Liu, Zhi-yong, Li, Xiao-gang
• Format: Article
• Language: English
• Subjects: Anodic dissolution; Bicarbonates; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Corrosion; Corrosion and Coatings; Crack tips; Dissolution; Electrochemistry; Glass; High strength low alloy steels; Materials Science; Metallic Materials; Natural Materials; Pipelines; SCC敏感性; Slow strain rate; Steel; Steels; Stress concentration; Stress corrosion; Stress corrosion cracking; Structural steels; Surfaces and Interfaces; Thin Films; Tribology; X80管线钢; 应力腐蚀开裂; 浓度; 碳酸氢盐; 稀溶液; 裂纹尖端; 高pH值
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-013-0778-4

Susceptibilities to stress corrosion cracking （SCC） of X80 pipeline steel in high pH solutions with various concentrations of HC03 at a passive potential of-0.2 V vs. SCE were investigated by slow strain rate tensile （SSRT） test. The SCC mechanism and the effect of HC03 were discussed with the aid of electrochemical techniques. It is indicated that X80 steel shows enhunced susceptibility to SCC with the concentration of HCO3 increasing from 0.15 to 1.00 mol/L, and the susceptibility can be evaluated in terms of current density at -0.2 V vs. SCE. The SCC behavior is controlled by the dissolution-based mechanism in these circumstances. Increasing the concentration of HCO3 not only increases the risk of rupture of passive films but also promotes the anodic dissolution of crack tips. Besides, little susceptibility to SCC is found in dilute solution containing 0.05 mol/L HCO3 for X80 steel. This can be attributed to the inhibited repassivation of passive films, manifesting as a more intensive dissolution in the non-crack tip areas than at the crack tips.