焊接裂纹金属磁记忆信号特征研究的进展

Progress in the Study of Metal Magnetic Memory Signal Features of Welding Cracks

反映焊接裂纹的金属磁记忆信号特征包括信号过零点位置、小波分析能量极大值点位置、傅立叶分析相位突变位置、区域信号的最大值与最小值差值、信号在检测方向上的梯度、信号在检测方向垂直方向上的梯度。以上6个信号特征通过金属磁记忆信号特征判断焊接裂纹的方法。可以描述焊接裂纹时的作用以及相互之间的关系。研究表明:过零点特征和小波分析极大值点位置特征是不可靠的,用其他4个特征来判断焊接裂纹得到的结论很可靠。未来需要建立用这4个特征来判断焊接裂纹的系统。

The paper studied the following six metal magnetic memory （MMM） signal features of welding cracks： the position where signal value is zero, the position where energy of wavelet analysis arrives at maximal point, the position where phases of the Fourier analysis mutate, difference between maximum regional signal＇s maximum and its minimum, signal gradient in the direction of detection and its gradient in the perpendicular direction. The above six signal features can judge welding cracks through using MMM signal features, and describe the inter-relationship among cracks during the course of welding them. The study shows preliminarily that the position where signal value is zero and the position where energy of wavelet analysis arrives at maximal point are not reliable, whereas the judgement of welding cracks using the other four signal features is highly reliable. The system for such judgement needs to be established.