关键词: X70, 钢级, 低温韧性, 螺旋埋弧焊管, 西气东输管道工程

Abstract: To satisfy the need for large-diameter and thick-wall X70 SAWH used for long-distance natural gas pipelines like the West-East gas pipeline project, Huayou Steel Pipe Co Ltd developed a new product ---X70 φ1016mm×17.5mm SAWH steel pipe. This product is localized and meets the requirement on the related technological standards of the West-East gas pipeline project. Of those standards, the transverse-to-pipe-axis yield strength averages 529MPa while the tensile strength averages 645MPa. The average value of TPA Charpy impact energy is higher than 300J (-10℃ ), the average value of weld Charpy impact energy 163J (-10℃ ), the average value of heat-affected zone Charpy impact energy 204J (-10℃ ), and DWTT shear area averages 100% (-10℃ ). The company also developed a series of new technologies, such as high steel grade, large-diameter and thick-wall low-stress forming technology, welding technology and dedicated welding materials, establishing the capacity for mass production. This product has been successfully used for long-distance natural gas pipelines, such as the West-East gas pipeline, the Shaanxi-Beijing gas pipeline and the second West-East gas pipeline. All the technological indexes of the steel pipe meet the requirements of the pipeline.

Key words: X70, low-temperature toughness, SAWH pipe, West-East gas pipeline project