An overview of new developments on linepipe steels and offshore structural steels at Posco

An overview of the development of linepipe and offshore structural steel manufacturing technology at POSCO is presented. As more energy production sites are being developed under the constrained conditions, there is currently a strong need for linepipe steels that can withstand severe conditions, such as extreme cold, deep seabed and corrosive environments. To meet current market needs, POSCO has developed API-X80/X100/sour X70 grade hot rolled strip and plates with low temperature toughness for energy transportation. Several mill trials with multiple process variables have been performed to optimize the production processes of high strength/high toughness linepipe steel, such as reheating/rolling/cooling conditions. API 2W Gr. 50 and 60 class steel plates have also been developed using TMCP techniques for offshore structures. Steel composition and manufacturing parameter were optimized to obtain high strength and good weldability. POSCO has now established an API Steel Application Center to provide total solutions for pipe manufacturers, energy firms, and construction companies. The API Steel Application Center consists of three laboratories, each specializing in pipe forming, pipe corrosion evaluation and welding research. Especially, in the forming laboratory, the world’s first UOE simulator is installed with several evaluation facilities for full-scale pipes. The UOE simulator can carry out U-ing, O-ing and expansion at the same machine. The present review describes the recent POSCO activity for new development of linepipe and offshore structural steels and briefly introduces the API Steel Application Center. (AU)