漏磁检测技术对钢板对接焊缝检测鲜有应用，根据铁磁性焊缝的特点，针对焊接结构中较敏感的裂纹缺陷，探讨应用漏磁法检测钢板对接焊缝裂纹缺陷。采用有限元数值模拟方法(FEM)，建立了焊缝三维FEM模型;对比分析焊缝不同区域存在裂纹时漏磁场分布规律;建立不同焊缝余高包含相同尺寸裂纹的三维FEM模型，分析由于焊缝余高的存在对裂纹检出率的影响;研究在焊缝余高3 mm结构条件下，漏磁场磁感应强度分量峰值随裂纹深度的变化规律，得到漏磁场相关对比分析曲线。仿真结果表明：漏磁法适用于钢板对接焊缝缺陷的检测研究;焊缝余高越小，可获得更高的缺陷检出率;漏磁场磁感应强度分量峰值均随裂纹深度的增加呈递增趋势。

Magnetic flux leakage(MFL) technology was seldom applied on testing for the butt weld of steel plate, in view of the characteristics of the ferromagnetic weld, butt welds cracks of the steel plate with MFL method were investigated according to the cracks that were relatively more sensitive to welded structure. 3D finite element method(FEM) model of the weld was established by using FEM; the MFL field distribution was analyzed comparatively when the crack exists in the different regions of the weld; 3D FEM models of different weld reinforcement with the same size cracks were established, also the effect of the detection rate of cracks because of weld reinforcement was analyzed; the laws were obtained representing distribution of the component peak of the magnetic induction to the change of the depth of the crack, and the curves were obtained representing distribution of the MFL field under 3mm conditions of weld reinforcement. The outcome indicates that MFL method is suitable for testing study of butt welds defect of the steel plate; the detection rate of defects is getting higher as the weld reinforcement is becoming smaller; the trends are increasing with the component peak of the magnetic induction of the MFL field to the change of the depth of the crack.