X90管线钢示波冲击特征值的研究

为了更准确地评价X90管线钢的韧性，利用示波冲击试验机提取了不同温度下该管线钢的载荷－位移曲线，研究了其冲击韧性随温度的变化情况。结果表明，在20 ℃和0 ℃时X90管线钢示波冲击曲线与GB/T 19748中的F型曲线相似，为韧性断口；－20 ℃以下时，可以看到明显的不稳定裂纹扩展特征；随着温度的降低，X90管线钢示波冲击的最大力基本不变，而屈服力升高；裂纹形成能，剪切唇及二次纤维区形成能基本不随温度变化而变化，仅当达到－100 ℃时，裂纹形成能，剪切唇及二次纤维区形成能急剧降低。稳定裂纹扩展能随着温度的降低而降低。

Instrumented Impact Characteristic Value Research on X90 Pipeline Steel

In order to more accurately evaluate the toughness of X90 pipeline steel,the load-displacement curve was extracted under different temperatures by using instrumented impact testing machine,and the impact toughness variation situation along with temperature was studied.The results showed that the instrumented impact curve of X90 pipeline steel at 20 ℃ and 0 ℃ was similar to the GB/T 19748 F type,was ductile fracture;-20 ℃ below,obvious unstable crack propagation characteristics can be seen;with the reduction of temperature,the maximum force of X90 pipeline steel instrumented impact basically unchanged,while the yield force increased;crack formation energy,shear lip and secondary fiber area formation energy almost unchanged as the temperature changing;only when the temperature reached-100 ℃,crack formation energy,shear lip and secondary fiber area formation energy decreased sharply.Stable propagation crack energy decreased with the temperature decreasing.