X80钢级管道环焊缝非均匀裂纹体断裂驱动力

Fracture driving forces of cracked girth welds with mechanical heterogeneity for X80 pipes

采用试验测试与数值模拟相结合的方法,研究了X80钢级管道环焊缝焊接热影响区的组织及其对断裂驱动力的影响.试验表征了焊接热影响区显微组织与硬度分布,研究表明热影响区存在软化现象;采用有限元数值模拟方法,将环焊缝简化为由母材、焊缝和热影响区组成的力学非均匀体,研究了焊缝匹配、焊缝宽度、软化区对环焊缝非均质裂纹体的断裂驱动力的影响.结果表明,随着焊缝匹配系数增加,环焊缝非均质裂纹体的断裂驱动力减小;相对于高匹配而言,低匹配焊缝的热影响区的软化对裂纹驱动力影响较大.

Microstructure,microhardness and fracture driving force are investigated experimentally and numerically for the heat affected zone of girth welds of X80 pipes in the paper.The soft region exists in the heat affected zone of girth welds,based on the experiment results of microstructure and microhardness distribution.By simplifing the girth welds with mechanical hetrogeneity into base metal,weld metal and heat affected zone,the fracture driving force of cracked girth welds are studied numerically with weld matching property,weld width and soft zone in heat affected zone.The results show that the fracture driving force decreases with the increase of weld matching property,and the soft region in the undermatched weldment has stronger effects on the fracture driving force of girth weld than that in the overmatched weldment.