漏磁结合涡流的非铁磁性金属材料探伤研究

Magnetic flux leakage combined with eddy current for non-ferromagnetic metal materials damage detection

针对非铁磁性金属的内外壁损伤检测问题,设计了一种中低频的交流电磁场检测模型,对漏磁及涡流效应在交流电磁场检测中的耦合机制进行了分析,并制作电磁检测装置进行实验验证。基于COMSOL有限元仿真建立二维仿真模型,针对不同深度、不同大小的表面缺陷及埋深缺陷进行仿真检测,得到相应的检测线圈电压幅值、相位与缺陷深度的关系;以仿真结果为基础制作了电磁检测装置,并对非铁磁性金属待测试件进行检测,结果表明,制作的电磁检测装置可以穿透18 mm不锈钢板检测到高5 mm、长12 mm的矩形埋深缺陷及上表面深3 mm、Ф5 mm的微型圆孔缺陷。结果表明,低频激励信号对于待测试件的上下表面缺陷均有良好的检测效果,而中频激励信号仅适用于上表面缺陷检测。

In order to detect the damage of the inner and outer walls of non-ferromagnetic metals, a medium and low frequency AC electromagnetic field detection model is designed. The coupling mechanism of magnetic flux leakage and eddy current effect in the detection of AC electromagnetic field is analyzed, and the electromagnetic detection device is made for experimental verification. Based on COMSOL finite element simulation, the two-dimensional simulation model is established. The simulation tests are carried out for surface defects and buried depth defects of different depth and sizes, and the relationship between voltage amplitude, phase of the coil and defect depth is obtained. Based on the simulation results, the electromagnetic detection device is made and the non-ferromagnetic metal test piece is tested. The results show that the manufactured electromagnetic detection device can penetrate the 18 mm stainless steel plate to detect a rectangular buried depth defect with a height of 5 mm and a length of 12 mm and a micro circular hole defect with a upper surface of 3 mm and Ф5 mm. It is concluded that the low frequency excitation signal has a good detection effect on the upper and lower surface defects of the test piece, while the intermediate frequency excitation signal is only suitable for the detection of upper surface defects.