漏磁法检测薄带钢内部缺陷的研究进展  

Research on steel sheet internal defects detection technology based on magnetic flux leakage

作　　者：石桂芬[1] 何永辉[1] 张清[2] 

机构地区：[1]宝山钢铁股份有限公司,上海201900 [2]华东师范大学,上海200062

出　　处：《世界钢铁》2013年第4期58-62,72,共6页World Iron & Steel

摘　　要：漏磁法检测带钢内部缺陷是利用铁磁性材料在磁场中的导磁现象,若材料中有缺陷存在,就会在材料表面缺陷处形成漏磁场,通过漏磁场大小即可检测出缺陷大小。文章中给出了基于漏磁技术的薄带钢内部缺陷检测试验结果。在试验中,采用厚度为0.13mm的薄带钢为检测对象,并在其上打出直径为0.13mm的通孔和盲孔作为人工缺陷,将钢板磁化至深度饱和,能够较好地得到该缺陷的漏磁信号。目前,日本太平工业和Nireco两家公司开发出的漏磁检测设备已经进入工业化大生产阶段,二者的缺陷检测精度分别为0.0014mm3和0.000373mm3。分析认为可以根据现场检测条件和检测精度需求选择合适的磁敏传感器,并采用直流磁化方法,将带钢磁化至深度饱和来保证微小缺陷信号的检出。采集到漏磁信号后,用小波分析法进行信号预处理,然后以统计法或者神经元网络法来实现缺陷尺寸量化,往往能够得到较为精准的检测结果。对漏磁技术应用中的难点和技术发展趋势进行了展望。The magnetic flux leakage method to inspect internal defects in steel sheet is based on ferro- magnetic material＇ s magnetic phenomena in magnetic fields. If there＇ s any defects in a ferro-magnetic material, magnetic flux leakage field will appear in the surface of the defects. By calculating the quantity of the magnetic flux leakage, defect＇ s size can be got. Testing results for internal defects in steel sheet is showed in this paper. In this test, the object detection is a piece of 0.13 mm thick steel sheet with pseudo defects, which are artificial holes and each hole＇ s diameter is 0.13 mm. The test showed that inspecting sensors could get good magnetic flux leakage signal when the steel sheet was deeply magnetized into saturated status. Two Japanese companies, TAIHEI and NIRECO, have developed magnetic flux leakage detecting devices with high inspecting accuracy, which are 0. 001 4 mm^3 and 0. 000 373 mm^3 respectively. And now they＇ ve already stepped into industrial production stage. By analysis, two factors, one is industrial site＇s inspecting conditions and the other is inspecting accuracy, should be considered into to select suitable magnetic sensors. Meanwhile, DC magnetizing is the best way to magnetize steel sheets into deeply saturated status. As a result of above consideration , the magnetic flux leakage signal of very small defects can be detected . After the signal is captured, the wavelet analysis method preprocesses the signal and then the size of defects can be calculated by statistical method or neural network method. In the end, the difficulties and technical trend for applications of magnetic flux leakage detecting technology in future has been discussed.

关 键 词：漏磁检测 内部缺陷 磁化 

分 类 号：TF777[冶金工程—钢铁冶金]