Magnetic particle testing or penetration detection can be useful to find the appearance of cracks, folds, double skin, hairline, pinhole appearance shortcomings. About ferromagnetic materials, magnetic particle testing method should be preferred, because of its high detection sensitivity; on non-ferromagnetic materials, such as stainless steel seamless pipe, then use soaked detection.
When the two remaining reserved ADX less, because the layout reasons detecting apparatus, two heads are sometimes not useful in detecting, and the end is capable of cracks or other defects site. If there is a potential end cracking tendency of the weld heat affected apparatus also allows potential expansion of cracks. Thus, we should also pay attention to the detection zone must seamless steel welding, expanding pipe ends to discover defects. On -line use of austenitic seamless insulation is damaged or when to have rain infiltrated the site, should be soaked focus detection to detect stress corrosion cracking or pitting and other shortcomings. However, detection of magnetic or soaked steel outer appearance can only be detected, internal appearance of the shortcomings of the powerless. Detection of internal appearance, particularly the detection of cracks class disadvantage, it is necessary to carry out after ultrasonic detector.
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