Magnetic particle testing or penetration testing for common defects in SSAW Steel Pipe. Spiral tube magnetic particle testing or penetration testing can effectively detect surface cracks, fold, re-skin surface defects, hairline, pinholes. For ferromagnetic materials, due to their high detection sensitivity, the magnetic particle detection method should be given priority; for non-ferromagnetic materials, such as stainless steel spiral tubes, the penetration inspection method should be used.
 
On-line austenitic steel spiral pipe, when the insulation is damaged or rainwater may have infiltrated into the site, pay attention to penetration test to find out the defects such as stress corrosion cracking or pitting corrosion. However, the magnetic powder or penetrant is only tested on the outer surface of the pipeline to detect the helpless surface internal defects. The inner surface of the detector, especially the crack defect detection, must be carried out by ultrasonic detection.


When there is less resection margin at the end of the spiral tube, the detection device for structural reasons sometimes fails to effectively detect the end of the spiral tube, and may eventually be the place where cracks or other defects exist. If there is a cracking tendency at the end of the spiral steel tube, the potential cracks may also occur due to the welding heat effect during the installation process. Therefore, it should be noted that after detecting some areas of welded spiral steel, the defects of prolonging spiral steel tip should be detected.