Anisotropy in Mechanical Properties and Corrosion of X-52 Pipeline Steel at Different Pipe Angles

Abstract

Non-uniform corrosion and cracking could occur at different pipe angles (different clocks) on oil and gas transmission pipelines. While this could be due to different environmental conditions surrounding the pipeline or nonuniformity in microstructure, mechanical and corrosion properties at different pipe angles. This study investigates corrosion and mechanical properties of X-52 pipeline steel at different pipe angles. In this regard, microscopic characterization, weight loss corrosion tests, electrochemical corrosion tests, and also mechanical characterizations tests (hardness, tensile and fracture toughness) were performed. Results showed that corrosion and mechanical properties of the X-52 pipeline steel was not uniform at different pipe angles and 180 degree (6 o’clock) position had the most corrosion rate and fracture toughness. Nonuniformity in grain orientations and microstructure of pipeline steel is considered to be the reason for anisotropy observed in corrosion and mechanical properties.