444铁磁性不锈钢焊管缺陷的识别与分类

Defect identification and classification of 444 ferromagnetic stainless steel welded pipe

基于涡流检测技术,提出一种针对444铁磁性不锈钢焊管的缺陷识别与分类方法。首先采集经过磁饱和处理后的钢管涡流信号,通过经验模态分解(EMD)进一步对涡流信号进行降噪,提取到最能代表原始信号特征的内涵模态分量(IMF),对所选取的IMF提取时频域特征参数;为了提高模型识别效率,通过主成分分析(PCA)对特征向量集降维;最后使用支持向量机(SVM)对焊缝缺陷进行识别与分类。试验结果表明,该方法对444不锈钢焊管各缺陷的识别准确率较高,生产中可将含有特定缺陷的产品自动筛选出来,提高了生产效率。

A defect identification and classification method for 444 ferromagnetic stainless steel welded pipes was proposed based on eddy current testing technology.In this method,the eddy current signal of the steel pipe after magnetic saturation processing was first collected,and the eddy current signal was further denoised by empirical mode decomposition(EMD),and the intrinsic modal component(IMF)which can best represent the original signal characteristics was extracted,and the time-frequency domain characteristic parameters were extracted from the selected IMF.In order to improve the efficiency of model recognition,principal component analysis(PCA)was used to reduce the dimension of eigenvector set.Finally,support vector machine(SVM)was used to identify and classify weld defects.The experimental results showed that the method had high accuracy in identifying the defects of 444 stainless steel welded pipe,and can be used to select the products with specific defects automatically to improve the production efficiency.