In the
spiral tube production test, there is no magnetic flux leakage detection method to detect the phenomenon of a large hole of a spiral steel pipe passing through a wall. In addition to management and human factors, the scoreboard should be technically investigated and prevented. The method can be used to detect the depth of surface defects stuck, there is no clear conclusion. It has a certain relationship with the size and shape of the instrument and the probe's performance and defects.
Spiral coil method for the detection of high-speed steel, for many years widely used in
ssaw steel pipe quality inspection, especially the tightness testing of rebar. In use proved that the ferromagnetic spiral tube is difficult to get stuck in crack-like defects, so a high standard of ET, using the probe coil et method. In addition, ET's method can actually hide such a simple problem that its face is deep and it seems that so far it has not formed a clear consensus. Many of the eddy current probe equipment often can not find the defects such as the "outer break" often produced by the spiral steel pipe. Often visible to the naked eye, but not the only alarm such as equipment embarrassment. The emergence of fan-shaped eddy current alarm device, so that this situation has undergone fundamental changes. However, selecting the correct instrument and correctly detecting and adjusting it is still an important issue that can not be ignored. Another important factor is the reliability of the natural angle of tube surface defects. Theoretical and experimental studies show that when the azimuth of the artificial groove along the thickness direction of the outer surface of the pipe is 30 degrees, the surface defects of the artificial groove can not be detected in parallel, such as class delamination defects.
