以搭接式铜铝过渡线夹为典型代表的双层异质金属构件广泛应用于能源、航空航天等重要工程领域。由于焊接控制条件不稳定等因素,双层异质金属构件的焊接界面处可能出现金属层减薄等界面缺陷,因此,对双层异质金属构件焊接界面缺陷实施有效的无损定量检测至关重要。聚焦于搭接式铜铝过渡线夹的无损检测,深入探究其焊接界面金属层减薄缺陷的暂态涡流检测技术。通过暂态涡流检测的有限元仿真计算,在分析检测信号对焊接界面缺陷响应特性的同时,提出了新型暂态涡流检测信号特征及金属层减薄缺陷定量评估方法。搭建了双层异质金属构件暂态涡流检测试验平台,通过试验,进一步研究焊接界面处金属层减薄缺陷的可视化定量检测方法。仿真和试验结果表明了所提暂态涡流检测信号新特征及定量评估方法在搭接式铜铝过渡线夹焊接界面缺陷定量检测中的有效性。

The Double-layer Heterogeneous Conductor (DHC) such as the lap-joint copper-aluminum transition terminal clamp is widely used in pivotal engineering fields including energy, aerospace, etc. The unstable welding control conditions would leave the welding interface vulnerable to interface damages such as the wall-thinning defect in the conductive layer, it is imperative to detect and evaluate welding-interface damages with effective nondestructive evaluation techniques. In this paper Transient Eddy Current (TEC) inspection of the wall-thinning defect occurring at the welding interface of a lap-joint copper-aluminum transition terminal clamp was intensively investigated. The characteristics of the TEC response to the interface damage were scrutinized via finite element analysis. A TEC signal feature and assessment method for evaluation of the wall-thinning defect were proposed. In parallel, an experimental platform of TEC inspection of DHC was built up for further investigation regarding imaging and evaluation of the wall-thinning defect at the welding interface. From the results of simulations and experiments, it was found that the proposed TEC signal feature and evaluation method were capable of quantitatively evaluating the interface damage of the lap-joint copper-aluminum transition terminal clamp.