THE CORRECT METHOD OF DEGAUSSING SPIRAL PIPE

Spiral Pipe degaussing method
1, with a coil wound pipe outside, to the coil through the AC, alternating current gradually decreases until it is reduced to zero. Degaussing Results: Does not change the physical properties of spiral steel pipe, however, in the event of an external magnetic field again, spiral steel pipe will be magnetized.
2, through the heat treatment process can be more thorough degaussing, however, after degaussing, spiral steel hardness and rigidity are subject to change, and then encountered when the applied magnetic field, magnetic field disappeared after the steel pipe will be substantially no residual magnetism in the future.
3, the heat treatment process, probably: anaerobic heated to a certain temperature, and then, with 72 hours to cool slowly to room temperature.
Cause of the magnetic field to produce spiral steel pipe
In the welding process, the welding DC welding, the welding horn and a big line positions due to the large current, generate a strong magnetic field, steel tube under the action of the magnetic field, the magnetic moments tend to acquire or to obtain the same magnetic field arrangement direction. When the end of welding, the magnetic field gradually reduced until it disappears, because the hysteresis in the tube as well as the presence of residual magnetic flux density, which is what we usually refer to the residual magnetism phenomenon.
Hazard spiral steel field
The existence of residual magnetism, image intensifier electron beam is deflected, X-ray image generation television system “S” type distortion, affecting the pores, slag and other natural defects, especially the lack of penetration, cracks and other defects in the linear nature detection rate.
As the impact of pipeline stages to improve the image intensifier and X-ray television systems change type, especially remanence.
The existence of residual magnetism when the pipeline butt welding ring, will have partial arc phenomenon, affecting the quality of welding, the presence of residual magnetism seriously affected the quality of construction.