中文摘要：

大变形管线钢因其较低的屈强比、较高的形变强化指数和较大的均匀伸长率,成为地震、滑坡、冻土等地质灾害地区油、气输送管道的首选材料。结合我国管道工程建设的要求,采用材料显微分析方法和力学性能测试等手段,对一种贝氏体＋铁素体X80大变形管线钢在预应变中的脆化规律进行了研究。结果表明,预应变使X80大变形管线钢产生脆化;随着预应变量的增大,该管线钢强度和硬度增加,塑性和韧性下降;预应变脆化形成的机理是管线钢位错亚结构的变化。

英文摘要：

Large deformation pipeline steel possesses low yield ratio, high deformation reinforcement index and high uniform elongation, so it is the preferred material of steel pipe for transporting oil and gas in geological disaster area, such as earthquake, landslide, frozen earth and so on. In this article, combined with the requirements of China pipeline engineering construction, it studied embrittlement regular of a kind of bainite＋ferrite X80 pipeline steel in prestrain by material microscopic analysis methods and mechanical properties test. The result showed that prestrain make X80 large deformation pipeline steel generate embrittlement.With prestrain increasing, the strength and hardness enhance, plasticity and toughness decrease. The Changes in the pipeline steel dislocation substructure cause prestrain embrittlement.