自安装井口平台外输海底管道疲劳拉伸磁记忆性能研究

Study on Tensile Magnetic Memory Performance of Self-installed Wellhead Offshore Pipeline

为研究自安装井口平台外输海底管道在地磁激励下疲劳拉伸过程中X80钢表面磁场信号变化规律,使用MTS810 250疲劳拉伸试验机对X80钢的拉伸试样进行了不同载荷下的疲劳拉伸试验。实验过程中借助磁记忆传感器对拉伸试样表面的磁记忆信号变化进行监测,借助手持显微镜观察疲劳过程中试样疲劳破坏情况,借助扫描电镜对断裂后的断口进行分析。结果表明:磁记忆对拉伸疲劳损伤敏感,并归纳提出了以切向信号极值、切向梯度信号极值的连线斜率为特征值的X80钢拉伸疲劳损伤敏感的磁记忆检测参数体系,为磁记忆检测方法的现场应用奠定了基础。

In order to study the variation of magnetic field signals on the surface of X80 steel during the fatigue tensile process of subsea pipelines transporting from self-installed wellhead platform under geomagnetic excitation,the fatigue tensile test of X80 steel samples under different loads was carried out using MTS810 250 fatigue tensile tester. During the experiment,the change of magnetic memory signal on the surface of the tensile samples was monitored by magnetic memory sensor,the fatigue failure of the samples was observed by hand-held microscope,and the fracture surface after fracture was analyzed by SEM. The results show that magnetic memory is sensitive to tensile fatigue damage,and a new testing parameter system of magnetic memory for X80 steel is proposed,in which the connecting line slope of the extremum of tangential signal and tangential gradient signal is taken as the characteristic value,it lays a foundation for the field application of magnetic memory testing method.