Development and trend of ultrasonic testing in automobile spot welding

Resistance spot welding is one of the most commonly used welding methods in the automotive industry. The welding process is short and complicated and the formation of the weld nugget is not visible. Thus it is necessary to monitor and assess the weld quality. In this paper,the inspection methods used for automobile spot weld quality were reviewed. Then ultrasonic testing technology was discussed emphatically,which includes the classification of ultrasonic detection system and the present products,signal processing methods,imaging technology,etc.At last,the current main challenges were summarized and the future development trend was introduced.