激光焊接缺陷多向磁场激励下磁光成像检测

为了研究交叉焊缝缺陷的磁光图像特征，对中碳钢板进行十字对接激光焊，获得同时具有横向和纵向焊后裂纹的试验样本，同时采用恒定磁场和交变磁场对试验样本进行多角度励磁, 用磁光成像传感器采集不同角度磁场激励下焊接缺陷处的磁光图像，并对磁光图像的缺陷特征进行分析。结果表明，多向磁场激励下的磁光成像技术能明显检测出多角度的焊接缺陷，且能有效避免曲线裂纹在焊接缺陷检测中的漏检现象; 同时，交变磁场激励下, 同一裂纹成像的分辨率提高了40pixel~50pixel，能更精确地定位缺陷位置。此研究为提高焊接缺陷的检出率提供了依据。

Magneto-optical imaging detection of laser welding defects under multi-directional magnetic field excitation

In order to study the magneto-optical image(MOI) characteristics of cross-weld defects, cross butt laser welding was performed on the medium carbon steel plate to obtain test samples with both transverse and longitudinal cracks. The test sample was excited by constant magnetic field and alternating magnetic field. Magneto-optical imaging sensor was used to collect magneto-optical images of welding defects under magnetic excitation from different angles. The defect characteristics of magneto-optical image were then analyzed. The results show that the magneto-optical imaging technology under multi-direction excitation can obviously detect multi-angle welding defects, and can effectively avoid the missing detection phenomenon of curve cracks in welding defect detection. The resolution of the same crack image is increased by 40pixel~50pixel under the excitation of the alternating magnetic field, which can locate the defect more accurately. This study provides a basis for improving the detection rate of welding defects.