中文摘要：

研究焊缝缺陷处的磁记忆信号变化规律.建立了地磁场下焊缝的磁偶极子模型,并模拟了其在有、无缺陷时的变化曲线,根据模型曲线的变化情况总结出了焊缝处存在缺陷时磁场强度的变化规律.通过检测自制焊接试件的磁记忆信号与模型进行对比.缺陷处的检测曲线与模型模拟的曲线具有很好的一致性.建立的磁偶极子模型能够反映实际焊缝处的磁记忆信号情况,可以对焊缝处缺陷进行评价.

英文摘要：

To study on the changes of magnetic memory signals of defects in the weld seam, a magnetic dipole model of weld seam in earth magnetic field was established. The change curves with defect and without defect in the weld seam were simulated. According to the changes of curves, the law of magnetic field changes when there were defects in the weld seam was obtained. The magnetic memory signals of the self made weld samples were tested to compare with the model. The testing curves with defects in the weld seam and the simulated curves matched each other well. The magnetic dipole model established can reflect the real situation of magnetic memory signals in the weld seam, and can be used to estimate the defects in the weld seam.