During the use of the magnetic drive pump, some users responded that the magnetic steel was demagnetized, resulting in the pump unable to operate normally. Therefore, it is considered to be the quality problem of the magnetic steel delivered by the company. However, after many after-sales analysis, we found that users had some problems in the early design or later use, resulting in demagnetization of magnetic steel. Therefore, in order to reduce the use cost of users and avoid unnecessary losses, let's talk about several major reasons for demagnetization of magnetic steel today. 1. The use temperature is unreasonable. The temperature of the material conveyed by the pump is too high, exceeding the allowable service temperature of the magnetic material. For example, for the pump with Nd-Fe-B magnetic steel, the service temperature should be less than 150 ℃. If the system temperature exceeds 150 ℃, the magnetic steel will be demagnetized soon. 2. Long time low lift operation. For example, if the flow at the rated point is 25 m3 / h and the head is 50 m, if it deviates from the rated point (for example, the head is only more than 10 meters), the return pressure inside the pump will drop, the circulation will be blocked, the eddy current belt of the metal isolation sleeve will not go, its temperature will rise sharply, and the magnetic steel will demagnetize. 3. Pipeline matching is unreasonable. For example, DN65 pipeline is required at the inlet. If the pipeline is less than 65mm, the flow will be in short supply, which will easily lead to poor internal circulation, heat is not easy to be taken away, and the system temperature exceeds the service temperature of magnetic steel. 4. The sliding bearing is worn and not replaced in time. If it is not replaced in time, there will be friction between the inner magnetic rotor and the inner wall of the isolation sleeve, resulting in the temperature rise of the isolation sleeve and demagnetization of the magnetic steel. 5. The magnetic pump runs idly. In this case, the temperature of the metal isolation sleeve and the inner magnetic rotor rises sharply, exceeding the service temperature of the magnetic steel, which will soon lead to demagnetization of the magnetic steel of the inner magnetic rotor. 6. The inlet and outlet pipelines of the pump are blocked. In this case, the magnetic pump idles, or the internal circulation of the pump is affected and the temperature rises; Moreover, the blockage of the outlet pipeline will also demagnetize the magnetic steel because the internal circulation of the pump cannot be carried out. If the pump inlet pipeline is equipped with a filter, the filter shall be cleaned regularly to ensure that the filtering area is within a reasonable range. 7. Abnormal jamming of rotor parts. The rotor component composed of internal magnet and impeller is stuck by mechanical impurities and cannot run, but the motor does not stop in time, which will lead to demagnetization of magnetic steel. 8. Cavitation. Cavitation of the pump due to various reasons will cause demagnetization of the magnetic steel.