Magnetic particle testing or penetration testing can effectively detect surface cracks, folding, heavy leather 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 seamless tubes, the penetration test method should be adopted.


When the two ends of the resected edge are few, due to the reason of Casino Kay, the detection device configuration sometimes lacks effective detection on both ends of the head, but it is most likely to end the site where there are cracks or other defects. If the end of the crack tends to have potential, the welding heat affected during installation may also produce potential cracks. Therefore, it should be noted that after detecting some welded areas of seamless steel pipe, defects should be found at the end of the pipe.


When on-line austenitic seamless steel pipe is damaged by insulation or rainwater may have infiltrated into the site, attention should be paid to penetration test to find out the defects such as stress corrosion cracking or pitting corrosion.


However, magnetic powder or penetration testing can only detect the outer surface of steel pipe, and the inner surface defects are powerless. The inner surface of the inspection, especially the crack detection of this defect, must be carried out by ultrasonic inspection.