Line pipe pieces: large-diameter high-voltage transmission and the use of high-grade steel pipes is an important trend in the development of international pipeline project. Increase the thickness and strength with the increasing demand for oil and natural gas, delivery pressure and diameter of the pipeline is also constantly increased in order to increase the efficiency of its delivery. Taking into account the structural stability and safety of the pipeline, the need to increase the strength and progress of the pipe wall thickness, and thus serves as the conduit of such pipeline specifications are thick and high-strength toward the direction of development. Due to the compressibility of natural gas, so gas pipeline delivery pressure pipelines to be relatively high. Most foreign pressure gas pipeline in recent years, from the early 4.5 ~ 6.4MPa increased to 8.0 ~ 12MPa, some pipelines can reach 14 ~ 15.7MPa, so that the gas pipeline grade accordingly progress. Foreign large-diameter gas pipeline has been widely used steel grade X70, X80 began to enter into the small-scale use phase, X100 also successfully developed and to begin developing the X120. Acidic pipeline transportation of natural gas has been able to produce to X65 steel grade. The use of large-diameter pipeline in the 21st century is the peak period of China gas pipeline construction. "West-East" pipeline with large-diameter, high-pressure pipeline approach. This pipeline total length of 4167km, the delivery pressure of 10MPa, diameter is 1016mm, steel grade used for the X70, a thickness of 14.6mm, lateral impact energy ~ 20 ℃ for ≥120J. The grade, size, toughness level the country has production and quality to meet international standards. Therefore, the production of this specification high strength, high toughness of pipeline to China in the future use of domestic production of large diameter pipeline, high pressure gas pipeline is of great strategic significance.