声发射技术在钢包耳轴环形焊缝安全检测中的应用

On the way to safety detect the circumferential welds for a steel ladle trunnion by using the acoustic emission technology

钢包耳轴焊缝缺陷是影响钢包安全运行的重大危险源,常规检测手段无法探测耳轴根部的疲劳裂纹。利用声发射平面定位技术对钢包耳轴焊缝进行检测,对检测数据进行滤波,以确定目标信号。利用希尔伯特-黄变换对目标信号进行EMD分解,对分解后的8个本征模态函数进行傅里叶变换,以确定其频率范围。结果表明,声发射技术对形状复杂的大型设备的结构完整性检测有独特优势。

The present paper is to introduce a method on how to detect the circumferential welding defects for a steel ladle trunnion by using the acoustic emission technology. As is known, ladles are essential part to move liquid metals at high temperature in metallurgical works. However, the defects in trunnionwelds of a steel ladle always tend to be major hazard sources leadingtothe safe operation of the ladles. But the conventional detection method can hardly find the fatigue cracks in the trunnion root. It is for this reason that we have been working at the problem and proposed a scheme that acoustic emission plannar location technology can be used forthe job in this paper. The givenmethodwe have developed can be used to examine the behavior ofmaterial deformation under stress by usingthe Acoustic Emission （AE） testing, which can be used as a nondestructive means for finding the defects in the structural proof testing and plant operation. Ourmethod is to use the SAMOS AE system, inwhich the testing device is a technologically advanced system based on PAC’s PCI8 Acoustic Emission and can be made highly exciting or stimulating. The method has been developed working at a low power, low bandwidth and multiple channels. The SAMOS AE system we have proposed is working through the process of collecting incoming hits into eventsanalyzing the entering times of the hits in an event to produce a source location. In the process, the data filtering has been done to find the target signals. The results of our trial using the method indicate that when keeping the pressure, noticeable localization events are going on in the two pul-l up stages on the trunnion on the south side of the same position. Then, we have chosen the location event on stage 2, channel 1, as the target signal. The signal itself can reveal the actual situation of the defects. Hilber-t Huang Transform and FourierTransform can be used for the spectrum analysis for this target signal. The application results prove that the acoustic emission technology has unique advantages for the integrated detection of large and complex structures.