Detection and determination of copper weld cracks of opposite joint circumferential weld in automatic welding for long distance pipeline

Copper crack is one of the common defects of opposite joint circumferential welding seam in automatic welding for long-distance pipeline. Phased array ultrasonic detection, TOFD detection and AUT (Automatic ultrasonic testing) are effective detection methods to detect copper cracks. X-ray detection has great limitations on the detection of copper cracks, which may show typical crack characteristics and even fail to detect copper cracks. The cracks of molten copper were detected by various detection methods, and the results showed that,the determination of automatic welding copper cracks should be combined with the above detection methods to accurately characterize the copper cracks.