Abstract: Based on the domestic and international standards for technical specifications on X70 and X80 welded pipes, this article analyzes the chemical composition of low-alloy, high-strength and tough X70 and X80 hot-rolled coiled plates and their welding material alloy system as well as the composition determination method. It also focuses on the technological bottlenecks of residual stress for development of domestic X70 and X80 spiral steel pipe. The residual stress distributed under the different work processes was compared in the different pipemaking processes and then the residual stress control method was proposed for spiral submerged arc welded pipe. Based on production for India’s Relais natural gas pipeline project and the eastern segment of Sino-Russian pipeline project, it was confirmed that toughness and residual stress of X70 and X80 spiral welded pipe products are well controlled thanks to adoption of low-alloy, high-strength and tough coiled plates and welding materials as well as the reasonable residual stress control method. With all functional indexes satisfying the demand for technological conditions, the product is a domestic leader in the area in terms of quality and fills a blank both at home and abroad.

Key words: X70 and X80, spiral submerged arc steel pipe, steel used for pipeline, residual stress

摘要： 针对国内外标准对X70、X80 焊管的技术指标要求, 分析了低合金、高强韧性X70、X80 热轧卷板化学成 分与焊接材料合金体系及组分研究确定方法; 结合目前制约国产X70、X80 螺旋钢管发展的残余应力技术瓶颈, 通过不 同制管生产过程中, 不同工序下残余应力大小分布情况的比对, 提出了螺旋埋弧焊管残余应力控制方法。通过印度瑞 莱斯天然气管线工程及中俄东线管道项目工程批量生产证明: 经采用研究开发的低合金高强韧性卷板及焊接材料, 合 理的残余应力控制方法所生产的X70、X80 螺旋焊管产品强韧性及残余应力控制良好, 各项性能技术指标均能满足技术 条件要求, 产品实物质量达到国内先进水平, 填补国内外空白。

关键词: X70/ X80; 螺旋埋弧钢管; 管线钢; 残余应力