Ultrasonic C-scan inspection of brazed joint in thin panel honeycomb structure

The non-destructive testing of brazed joint in honeycomb structure with thin panel（thickness: 0.2 mm) was studied by ultrasonic C-scan method. Samples with different types of artificial defect were designed; the characteristic signal and the main parameters of the test were determined by the pre-experiment, and then parameters were optimized by orthogonal design, finally the optimum process was verified by a single panel sample. The multiple reflection echoes were chosen as the characteristic signal. The optimal C-scan results were achieved when the 20 MHz focus probe was used, and the pass band range for received signal were selected as 8-17.5 MHz. The defects such as incomplete penetration and core damage can be detected with ultrasonic C-scan, and the detection accuracy can reach to 1 mm.