在石油石化行业中，储罐底板经常发生腐蚀而进行补板维修。对有补板的储罐底板的腐蚀情况进行准确评价是检测人员面临的迫切需要解决的问题。采用漏磁检测技术对储罐底板和补板进行研究分析，建立了补板缺陷漏磁场的有限元模型，得到了缺陷不同位置时漏磁场的空间分布特性。在实验室条件下进行缺陷不同位置的对比试验，试验结果与仿真分析一致。磁化结构在磁化被检件过程中，会先把补板磁化至近饱和状态，磁化程度和单板试验的磁化程度相差不大，但补板缺陷处产生的漏磁场会优先从未被磁化至饱和状态的原底板中穿过，致使缺陷量化结果小于实际值。

In the petroleum and petrochemical industry, tank bottoms are often corroded and patch repairs are performed. Accurate evaluation of the bottom corrosion of the tank floor with patch plates is an urgent task for the inspectors. In this paper, the magnetic flux leakage detection technology is used to study and analyze the tank bottom plate and the patch plate. The finite element model of the leakage magnetic field of the patch defect is established, and the spatial distribution characteristics of the leakage magnetic field at different positions of the defect are obtained. Experiments were carried out on different positions of defects under laboratory conditions. The experimental results were consistent with the simulation analysis. The magnetization structure magnetizes the plate to a near-saturation state during the magnetization of the part to be inspected. The degree of magnetization and the degree of magnetization of the single plate experiment are similar. However, the leakage magnetic field generated at the patch defect will preferentially pass through the original substrate that has not been magnetized to saturation, resulting in a defect quantification result that is smaller than the actual value.