铝合金回填式搅拌摩擦点焊缺陷的超声检测及信号识别  

Ultrasonic Testing and Signal Identification of the Defects in Aluminium Alloy Refill Friction Stir Spot Welding

作　　者：孙静茹 李京龙[1] 豆建新 熊江涛[1] 石俊秒 赵华夏 SUN Jing-ru;LI Jing-long;DOU Jian-xin;XIONG Jiang-tao;SHI Jun-miao;ZHAO Hua-xia(Shaanxi Key Laboratory of Friction Welding Technologies,State Key Laboratory of Solidification Processing,School of Materials Science and Engineering,Northwestern Polytechnical University,Xi'an 710072,China;AVIC Manufacture Technology Institute,Beijing 100024,China)

机构地区：[1]西北工业大学材料学院凝固技术国家重点实验室陕西省摩擦焊接技术重点实验室,西安710072 [2]中国航空制造技术研究院,北京100024

出　　处：《精密成形工程》2019年第6期65-72,共8页Journal of Netshape Forming Engineering

摘　　要：目的利用水浸聚焦超声C扫描对2524铝合金回填式搅拌摩擦点焊(RFSSW)接头进行检测并完成缺陷识别。方法以A扫描时域信号为对象,绘制能量谱与金相作对照,确定焊合区;分析未焊合、聚集型孔洞及弥散型孔洞的时域和频域波形特征,并对频域信号进行小波分析,提取特征量。结果缺陷区反射回波的归一化能量不低于0.02;不同形式的缺陷(聚集型孔洞、弥散型孔洞、弱连接)其频谱形状特征不同,具有不同的峰值个数。结论通过金相验证,表明超声波C扫描对接头缺陷可进行有效的检测和区分。The paper aims to conduct immersion ultrasonic C-scan test for identifying different defects of the 2524 aluminum alloy joints with refill friction stir spot welding(RFSSW). With A-scan signal as the object, the energy spectrum was compared with the microstructures to determine the welded area. The time-domain and frequency-domain waveform characteristics of the unwelded, aggregated and dispersed holes were analyzed. The frequency-domain signal was analyzed by wavelet analysis to extract the feature. The normalized energy of reflection echo in the defect zone was not less than 0.02;different defects(aggregated, dispersed holes and kissing bond) had different frequency spectrum features and different peaks. The result of metallographic verification demonstrates that ultrasonic C-scan can effectively detect and distinguish defects of the joints.

关 键 词：回填式搅拌摩擦点焊 超声检测 时频变换 小波分析 

分 类 号：TG441.7[金属学及工艺—焊接]