Mechanical Properties and CO₂ Corrosion Behavior of High Strength and Toughness X80 Pipeline Steel

Abstract:

A type of X80 grade high strength and toughness pipeline steel was designed and researched. The strengthening mechanism of the steel was analyzed by SEM, TEM and XRD, and the CO₂ corrosion behavior of the steel was simulated by high-temperature and high-pressure autoclave. The result shows that the microstructure of the base metal is mainly acicular ferrite with a small amount of granular bainite. Acicular ferrite consists of laths which occlude and interweave with each other, and there are many dislocation and carbonitrides distributing in acicular ferrite, which made the pipeline steel have good strength and toughness. Under the simulation of the actual working conditions, the activity of reactants is low at 30°C, so the corrosion rate is smaller at this temperature; the maximum of corrosion rate occurs at 60°C; when the temperature increases to 90°C, the corrosion rate is lower than that of 60°C, that is because hindering corrosion effect which take by the acceleration deposit of corrosion product is better than the acceleration corrosion reactions.

• Periodical: Advanced Materials Research (Volumes 1010-1012)
• Pages: 1709-1712
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1010-1012.1709
• Online since: August 2014
• Authors: Li Dong Wang*, Feng Lei Liu, Hui Bin Wu
• Keywords: Acicular Ferrite, CO₂ Corrosion, Corrosion Product Scales, Pipeline Steel

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