为探究表面粗糙度对涡流检测的影响,对不同粗糙度表面上的裂纹开展涡流检测试验。结果表明:在较为粗糙的工件表面,裂纹能否被有效检测不仅取决于粗糙度的大小,还跟加工方式和纹理有关。将粗糙表面等效为多个以Ra值为深度的裂口,从等效裂口对涡流产生截断的角度,分析了工件表面场强度分布;通过分析裂口对电子流动的阻碍,得出了表面粗糙度与工件电导率的关系。
To explore the influence of surface roughness on eddy current testing,a series of experiments was applied to work pieces with different surface roughness value Ra.The experiment results show that:for work pieces with rough surface,the detectability of defects is not only dependant on the roughness value but also on the ways of manufacturing and texture.In this paper,the rough surface is equivalent to numbers of defects with depth of Ra.The distribution of magnetic field is analyzed on the basis of the truncation of eddy current caused by equivalent defect.Furthermore,the influence of surface roughness on specimen conductivity is proposed based on the hinder of electron flow caused by equivalent defect.