0.8设计系数用X80管线钢失效评估曲线研究

Study on Failure Assessment Curves(FAC) of X80 Pipeline Steel with 0.8 Design Coefficient

为了研究西气东输三线用0.8设计系数X80管线钢断裂性能,通过单轴拉伸和断裂韧性试验建立失效评估曲线和拟合方程,对3种不同屈强比的0.8设计系数X80管线钢管进行了失效评估。结果表明:与常用X80管材的失效评估曲线不同,选择3曲线并不是最保守曲线;高、低屈强比钢管的评估曲线在载荷比大于某一临界值时发生分离,高屈强比钢管的评估曲线在低屈强比钢管的评估曲线之下;屈强比大于0.9时,安全应用范围迅速减小。

In order to study the fracture performance of X80 pipeline steel used for the Third West-to-East Gas Pipeline Project with 0.8 design coefficient, it set FAC and fitted equations through uniaxial elongation and fracture toughness test, and conducted FAC for 3 different yield ratio X80 pipeline steel with 0.8 design coefficient. The results indicated that the third curve is different from FAC commonly used for X80 pipeline steel, it is not the most conservative curve. The FAC of high and low yield ratio separate when the load ratio is higher than a critical value, the FAC of high yield ratio steel pipe is below that of low yield ratio steel pipe; when the yield ratio is higher than 0.9, the security application range shorten rapidly.