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运用超声波扫描显微镜对点焊接头进行超声波C扫描检测,分析了不同焊接工艺条件下的C扫描图像及其演变特征,同时研究了C扫描图像各特征区域A扫描信号的变化特征;通过拉剪试验获得了接头抗拉强度、峰值位移以及能量吸收值等力学性能参数,探讨了点焊接头C扫描图像与各力学性能参数之间存在的对应关系.结果表明:超声波C扫描图像能够反映点焊接头内部形貌特征;通过A扫描信号可以甄别C扫描图像的特征区域;当供给压力为0.15 MPa时,超声波C扫描图像可以呈现飞溅、过烧等焊接缺陷;随着供给压力的增大,焊核直径逐渐增大,接头能量吸收值、峰值位移与抗拉强度等力学性能均呈现先增大后减小的变化趋势.
The ultrasonic scanning microscopy was used to inspect the spot welding joint by ultrasonic C-scan. The C-scan images and their evolution characteristics under different welding conditions were analyzed. At the same time, the changing characteristics of A-scan signal in each characteristic area of C-scan image were studied. The mechanical properties such as tensile strength, peak displacement and energy absorption were obtained, and the corresponding relationship between the C-scan images and the mechanical parameters was discussed. The results show that the ultrasonic C-scan images can reflect the spot welding joints The internal structure of the C-scan image can be distinguished by the A-scan signal. When the pressure is 0.15 MPa, the ultrasonic C-scan images can show the welding defects such as splashing, over-burning and so on. With the increase of the supply pressure, Diameter increases gradually, the joint energy absorption, peak displacement and tensile strength and other mechanical properties showed an increasing trend first and then decrease.