SSAW common defects magnetic particle testing or penetration testing. Spiral pipe magnetic particle testing or penetrant testing can be effectively found that surface cracks, folding, re-skin surface defects, hairline, pinholes. For ferromagnetic materials, magnetic particle testing method should be given priority, because of its high detection sensitivity; for non-ferromagnetic material, such as stainless steel spiral pipe, is used penetrant inspection method.
Online austenitic steel spiral pipe, when the insulation is damaged or rain may have infiltrated the site, note that penetration testing to find stress corrosion cracking or pitting and other defects. However, magnetic particle or penetrant testing only on the outer surface of the pipe to detect internal defects in the surface of the powerless. The inner surface of the detector, especially crack type defect detection must be carried out by ultrasonic testing.
When the spiral pipe ends aside less resection margin, due to structural reasons detection device, spiral pipe ends head sometimes can not be effectively detected, and the end is the most likely site of the presence of cracks or other defects. If the spiral steel pipe ends there is potential for cracking tendency, weld heat affected during installation may also make potential crack. Therefore, it should be noted that after the detection of certain welded spiral steel area, to detect extended spiral steel tip defects.
