Abstract: The Stress concentration is the main reason of damage to ferromagnetic metal pipelines. Through effective detection,the use status of metal pipelines can be predicted and the safety of equipment can be effectively guaranteed. The ferromagnetic effect of the material under stress is analyzed by the energy balance theory of ferromagnetic materials. The 3D simulation model of ferromagnetic materials is built by simulation software based on the metal band theory, and the magnetic effect characteristics of the system under tension stress are calculated. The weak magnetic field detecting sensor based on differential symmetrical structure is designed and manufactured. The stress concentration system of different types of pipelines is detected by the stress detection system based on the weak magnetic sensor. The stress concentration is verified by other stress detection methods. The results show that the weak magnetic sensor can effectively detect the weak magnetic field signal on the pipeline surface, and the weak magnetic field signal shows violent fluctuation characteristics in the stress concentration region. Various detection methods verify the effectiveness of the weak magnetic stress detection. Weak magnetic stress detection technology can effectively detect pipeline stress concentration caused by defects or deformation.

Key words: Metal pipeline, Weak magnetic effect, Weak magnetic sensor, Stress testing

摘要： 应力集中是造成铁磁性金属管道破坏的主要原因，通过应力的有效检测，可对金属管道的使用状态进行预判，有效保障设备的使用安全。利用铁磁材料能量平衡理论，对应力作用下的材料弱磁效应进行了分析；通过基于金属能带理论的仿真软件建立铁磁材料三维仿真模型，计算了拉应力作用下体系的磁效应特征；设计制作基于差动对称结构的微弱磁场检测传感器，通过基于弱磁传感器的应力检测系统对不同类型的管道应力集中状态进行检测，并利用其他应力检测手段对应力集中情况进行了验证。结果表明，弱磁传感器可有效检测管道表面的弱磁场信号；在应力集中区，弱磁场信号表现出剧烈的波动特征；各种检测手段均验证了弱磁应力检测的有效性，弱磁应力检测技术可有效检测由缺陷或变形等导致的管道应力集中。

关键词: 金属管道, 　弱磁效应, 　弱磁传感器, 　应力检测