X80管线钢拉伸载荷作用下磁记忆效应

摘要

In order to study the metal magnetic memory effect of X80 pipeline steel, the tensile loading and unloading tests and off-line magnetic field measurement of plate specimen were carried out at different load levels. Combined with the polynomial fit and vector analysis, the variations of extreme value of longitudinal component, gradient value of normal component and magnetic field vector were obtained. According to the model for equivalent magnetization of stress, the evolution of magnetic field was explained. The results show that the variation of extreme value of longitudinal component of magnetic field is consistent with gradient value of normal component, and the magnetic field vector will be reversed under coupling effects of loading environmental magnetic field and tension load. When the load is less than 20 kN, the extreme value of longitudinal component and the gradient value of normal component increase slowly, but the amplitude of the magnetic field vector and the angle between the magnetic field vector and the tension axis decrease slowly. When the load is greater than 20 kN, the extreme value of longitudinal component, the gradient value of normal component and the amplitude of the magnetic field vector increase rapidly, and the direction of the magnetic field vector tends to be not changed.%为研究X80管线钢的金属磁记忆效应，通过不同载荷水平的板材拉伸加-卸载以及离线磁场测量，结合多项式拟合与矢量分析，得到试件表面磁场长度方向分量极值、法向分量梯度值以及合成矢量的变化规律，并根据应力等效磁化模型对其进行解释。研究结果表明：在加载环境磁场和拉伸载荷的耦合作用下，磁场长度方向分量极值和法向分量梯度值均呈现出单调递增的变化规律，而磁场矢量会发生反转。当载荷在20 kN以内时，长度方向分量极值和法向分量梯度值均随载荷幅值增加而缓慢增加，磁场矢量大小及其与长度方向的夹角随载荷增加而缓慢减小；而当载荷大于20 kN时，长度方向分量极值、法向分量梯度值以及磁场矢量大小均呈线性增加趋势，磁场矢量方向发生反向并逐渐趋于恒定。