Darmawan Hidayat, Silmi Ath-Thahirah Al-Azhima, Rahadian Zainul, Nendi Suhendi Syafei
This study evaluates the combined effects of applied tensile stress and exposure duration on the corrosion behavior and stress-corrosion cracking (SCC) susceptibility of API 5 L Grade B pipeline steel in acidic sour environments representative of oil and gas service. Although this steel grade is widely used for pipelines due to its mechanical strength and cost efficiency, its long-term integrity is strongly influenced by the interaction between mechanical loading and corrosive media containing CO₂ and H₂S. Specimens were subjected to three tensile stress conditions corresponding to small deformation, notching, and necking (σ/YS ≈ 1.30–2.92), followed by immersion in 1.0 M acetic acid saturated with CO₂ and H₂S for up to 1510 h. Corrosion rates were determined using weight-loss measurements, while SCC morphology, microstructural degradation, and surface chemistry were characterized using optical microscopy, SEM, and EDS. The results indicate that increasing tensile stress significantly accelerates corrosion and promotes SCC initiation by destabilizing surface films and enhancing localized plastic deformation. Although corrosion rates decline with longer exposure due to the formation of an FeCO₃ film, this apparent reduction does not prevent localized damage under high stress. Crack morphology gradually shifts from mainly transgranular SCC at moderate stress to a combination of transgranular and intergranular cracking with severe deformation and extended exposure. Elemental analysis supports repeated rupture of corrosion films and continuous crack growth in highly stressed areas. These findings demonstrate that applied tensile stress is the dominant factor governing SCC susceptibility, while exposure time primarily moderates corrosion kinetics. The results emphasize the need to incorporate operational stress levels into pipeline integrity assessment and lifetime prediction for sour service conditions. © The Author(s) 2026.
Department of Electrical Engineering, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang km. 21 Jatinangor, Sumedang, Indonesia; Program study Industrial Automation Engineering and Robotic Education, Faculty of Technology and Vocational Education, Universitas Pendidikan Indonesia, Jl. Setiabudi no. 299, Bandung, Indonesia; Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Negeri Padang, Padang, Indonesia
