高强度管线钢落锤撕裂性能的试验

Experimental research on DWTT performance of high-strength pipeline steel

以X80管线钢为试验材料,采用金相显微镜和扫描电子显微镜,研究了显微组织、M/A、夹杂物对管线钢落锤撕裂性能的影响。结果表明,管线钢落锤撕裂性能(DWTT)随着多边形铁素体体积分数的增加而改善,当多边形铁素体的体积分数超过某一临界值(约28%)后,DWTT性能开始降低;组织中的M/A岛细小且弥散分布,其尺寸控制在纳米级别有利于改善DWTT性能;针对本研究试验钢,若其厚度方向上组织均匀、组织中铁素体体积分数为28%、M/A岛平均尺寸和比例分别为0.42μm和2.8%时,试验钢具有最好的落锤撕裂性能(韧性剪切面积率94.5%)。

The effects of microstructures,martensite/austenite(M/A)and inclusions on the drop weight tear test(DWTT)of X80 pipeline steel were studied by means of metallographic microscope and scanning electron microscope.The results show that DWTT performance improves with the increasing of polygonal ferrite(PF)volume fraction.For the test steel,if the structure is uniform in the thickness direction,the ferrite volume fraction in the structure is 28%,and the average size and ratio of M/A islands are 0.42μm and 2.8%,respectively,the test steel has DWTT performance(toughness shear area ratio 94.5%).