When both ends of the reserved resection margin less, due to the structural reasons of the detection device, both ends of the head and sometimes the lack of effective testing, the end is most likely there are cracks or other defects in the site. End there is a potential crack tendency, the installation of the weld heat affected may also be potential crack propagation. Therefore, it should be noted that the detection of a certain region of the welded seamless steel pipe, the timely detection of defective expansion of the pipe ends.
Magnetic particle testing, penetrant testing can be effectively found that the surface crack, fold, double skin, hairline, pinhole surface defects. Ferromagnetic material, should give priority to the use of magnetic particle testing method, because it has a high detection sensitivity; non-ferromagnetic material such as stainless steel seamless pipe penetration assay.
Magnetic powder or penetration testing only in the steel pipe surface to detect internal and surface defects are powerless. The internal surface detection, especially detection of crack defects, must be to be detected by ultrasound.
With austenitic seamless steel pipe should be noted that when the insulation is damaged or there may be rain infiltrated the site, penetrant testing, to detect stress corrosion cracking or pitting defects.
