涡流检测中的电磁场在空间中的衰减速度较快,传感器尺寸是影响涡流检测灵敏度的重要因素。采用尺寸较大的磁通门磁强计实现了304不锈钢20 mm深度处、铝合金16 mm深度处的检测,同时对试验过程进行了数值模拟,发现磁场B_x信号最大变化量的实际结果比数值模拟结果低33%~44%,但定性上两者符合得较好;数值模拟发现,小尺寸高灵敏度磁传感器涡流检测的灵敏度大幅优于感应线圈涡流检测仪的灵敏度,传感器的小尺寸可以弥补磁灵敏度上的劣势;同时可根据传感器尺寸与灵敏度绘制灵敏度需求曲线,比较不同传感器的涡流检测灵敏度。该结果有助于优化新型涡流传感器的设计。

The electromagnetic field in eddy current detection decays rapidly in space, and the sensor size is an important factor affecting the sensitivity of eddy current detection. A large flux-gate magnetometer was used to achieve the detection of 304 stainless steel at a depth of 20 mm and aluminum alloy at a depth of 16 mm. At the same time, the numerical simulation of the test process was carried out, and it was found that the actual results of B_x signal maximum variation were 33%~44% lower than the numerical simulation results. However qualitatively both of those two results were in good agreement. Numerical simulation shows that the sensitivity of small size and high sensitivity magnetic sensor in eddy current detection was much better than that of induction coil eddy current detector. Small size of the sensor could make up for the disadvantage of magnetic sensitivity. At the same time, the sensitivity demand curve could be drawn according to the sensor size and sensitivity to compare the eddy current detection sensitivity of different sensors. The results were helpful to optimize the design of new eddy current sensors.