Overview of development and commercialization of X120 ultra-high strength UOE linepipe

High-pressure operation through high strength linepipe reduces the long distance transportation cost of natural gas. In order to maximize the cost reduction, X120 UOE pipe has been developed. Low C - high Mn - Mo- Nb - Ti - B steel with a fine-grained lower bainite (LB) dominant microstructure realizes high strength, excellent low temperature toughness and good weldability. The boron-added, low carbon steel is also suitable for achieving good long seam HAZ toughness. In addition to the plate development, UOE forming technology and seam welding technology were tough challenges but successfully developed. Suitability for use in a pipeline system was demonstrated through an extensive development program that included burst tests, fracture toughness evaluation, girth welding technology, etc. A 1.6 km demonstration line was successfully constructed. (AU)