Research on defect imaging and detection technology for brazed copper-aluminum transition clamps based on multiple channels ultrasonic phased arrays

Brazed type copper-aluminum transition clamps are widely applied in power transmission systems. The interface quality influences electrical conductivity and operational safety. Traditional ultrasonic detection methods have limitations in identifying defects at dissimilar metal interfaces, including insufficient resolution and difficulty in quantitative analysis. An ultrasonic phased array technology (PAUT) based detection method has been proposed in this paper. A set of artificial calibration blocks with typical artificial defects has been designed and machined. High-precision imaging and quantitative assessment of copper-aluminum brazing interface defects based on image reconstruction and signal analysis algorithms has been achieved. Experimental results confirm that this method could effectively identify defects of 2mm diameter or 0.3mm depth lack-of-fusion zone. This method shows good repeat ability and applicability.