钢包耳轴活性缺陷声发射信号特征与定位分析

Active defects of ladle trunnions acoustic emission signal characteristics and sources location analysis

钢包耳轴是整个钢包结构的关键部位之一，耳轴根部在长期的高温吊拉作业中会产生活性疲劳裂纹．针对常规超声法难以对耳轴根部焊缝进行无损检测的问题，提出基于声发射（Acoustic emission，AE）平面定位技术对钢包耳轴根部焊缝活性缺陷进行检测的方法．对原始AE数据进行滤波处理并结合小波包变换对信号进行分析．实验结果表明该方法能够较准确定位焊缝活性缺陷的位置．经过小波包对AE信号进行3层分解与重构后，活性缺陷AE信号频带主要分布在62．5—125kHz，其能量占总能量的81．25％，符合一般裂纹扩展的频率特征．

Trunnions are one of the core components of a steel ladle, active fatigue cracks may emerge in the trunnion roots for a long time hauling operation under ]high temperature condition. To overcome the difficulty of conventional ultrasonic method in detecting the weld of the trunnion roots, a inspection scheme based on acoustic emission （AE） plane location for the non -destructive testing（NDT） of the weld active defect of the trunnion roots was proposed. The original AE data was filtered and wavelet packet transform was used for the AE signal analysis. Results showed that the position of the weld active defect is located relatively accurate with the method. 3 - layers decomposition and reconstruction was performed with the AE signal using wavelet packet, the frequency domain of active defect AE signal is mainly distributed from 62.5 to 125 kHz and the signal energy account for 81.25 % of the total energy, agreeing with the general frequency characteristics of the crack propagation.