Seamless Steel Tube Common Defects on Magnetic Particle Detection or Penetration Testing

Magnetic particle detection or osmotic osmosis detection can effectively detect surface cracks, folding, heavy skin, hair lines, pinholes and other surface defects. For ferromagnetic materials, magnetic particle inspection method should be given priority, because of its high detection sensitivity; for non-ferromagnetic materials, such as stainless steel seamless pipe, the use of osmosis osmosis detection method.

When the cut-off allowance is small at both ends, the two ends are sometimes not effectively detected because of the structure of the detection device, and the end is the site most likely to have cracks or other defects. If there is latent crack tip tendency, the installation of the welding heat effects are also possible to latent crack propagation. Therefore, should also pay attention to a certain area of seamless steel pipe after welding detection, the timely detection of defects in the expansion of steel pipe head.

On the use of austenitic seamless steel pipe, when the insulation layer damage or possible rain infiltration of the site should pay attention to the osmotic oozing test to find stress corrosion cracking or pitting and other defects.

However, the detection of magnetic powder or osmotic osmosis can only detect the outer surface of the steel pipe, the inner surface of the defect is powerless. The detection of the inner surface, in particular the detection of crack-like defects, must be achieved through the ultrasonic detection.