Adoption of commercial production of X65 plate steel for deep-water gas pipelines at Azovstal Iron & Steel Works and Welspun Pipe Company

This paper describes the metallurgical approach used for the production of 160 miles of 36” OD X-65 linepipe in thicknesses up to 31 mm (1.25 inch) which was installed in several hundred feet of water in the Gulf of Mexico. The project was conceived and executed by GulfTerra (now Enterprise Products) and is named Cameron Highway Offshore Project. At the time of completion it represented the longest offshore pipeline in the Gulf of Mexico. A low carbon niobium microalloyed steel was produced and rolled at Azov Stal. Careful attention to continuous casting and rolling conditions resulted in plate and pipe that had uniform microstructure throughout the thickness and excellent notch toughness. (AU)