<b>Accelerated Corrosion Behavior and Degradation Mechanisms of API X70 Line-Pipe Steel in Seawater and Sodium Thiosulfate Solutions: Implications for Long-Term Durability in Aggressive Marine Environments </b>

This experimental evaluation studies API X70 line-pipe steel which metal industries use for oil and gas transportation and pressure vessel applications due to its outstanding mechanical characteristics and longevity. The research evaluates steel substrate behavior while it remains immersed in seawater and sodium thiosulfate solutions throughout 50 days. API X70 displays excellent strength properties but its durability becomes questionable when used in severe highly corrosive circumstances like ocean water. The research determines both the steel material degradation rates and structural deterioration in addition to weight reduction in this corrosive environment. Scientists designed a testing environment which recreated offshore pipeline conditions to disclose the material degradation pattern in aggressive solutions. The experimental outcomes show that sodium thiosulfate solution promotes different rates of corrosion in comparison to seawater. The sodium thiosulfate solution enhances corrosion activity by increasing both pitting depth and corrosion rate because of sulfur compounds within the solution. This work reports weight measurements obtained from laboratory-exposed API X70 test pieces together with calculated corrosion values and general performance assessments. Essential information regarding the extended durability of API X70 line-pipe steel when exposed to marine conditions along with important data helps designers and maintenance professionals for proper line-pipe structure design particularly in sulfate-rich waters. Sulfide contamination requires methods for prevention to stop premature degradation of the material