There are two ways to get rid of the damage caused by the magnetic conductivity of ferromagnetic materials to the flaw detection. First, the far field eddy current flaw detection device is selected for eddy detection. Second, the steel tube is magnetized in the saturated state and then tested. The former method must upgrade the instrument and equipment, while the latter method only needs to basically improve the magnetic saturation state device of the original basic instrument and equipment to carry out flaw detection on steel pipes, etc., which has the advantage of less project investment. A ferromagnetic material that has undergone a saturation state can be treated as a magnet material.
In general, magnetic saturator is used for vortex testing of steel tube. The coil with DC power supply is used to create a stable magnetic field, and the magnetic field is channeled to the flaw detection part of the steel tube to be tested by means of the magnetic absorbing component of the guide column contour line, so that it can achieve magnetic saturation. In order to make better use of the electromagnetic field created by the coil, the device is generally made of a ferromagnetic material (such as pure iron) housing. Because the μ value of pure iron is very large and the magnetoelectric type is not large, the magnetic induction line leaked in the indoor space will be collected by the shell and dredged to the detection part of the steel pipe.
Because the strong magnetized current flow will make the coil hot according to the magnetic saturator coil, it is necessary to have excellent heat transfer countermeasures to prevent coil damage.
In addition to creating a strong alternating current electromagnetic field, the magnetic saturation state device is often used to clamp the inspection coil industrial eddy current flaw detector, so the structure of the magnetic saturation state device is closely related to the appearance design of the hardness eddy current flaw detection coil. In the cross scroll flaw detection, the guide post in the magnetic saturation state device is kept in the same boat with the detection coil, otherwise it will lead to great poor axial sensitivity, resulting in missed and false detection.