What problems should be paid attention to in the use of electrical grade magnesium oxide powder?
1. For stainless steel components with relatively long tubes (such as 4-6 meters), they must be annealed at a high temperature of 900°C before bending. In this case, the resistance wire should be made of nickel-chromium wire instead of iron-chromium wire as much as possible. Because aluminum (Al) is particularly easy to deprive the oxygen in the MgO powder at 900℃ (aluminum and oxygen have a strong affinity), the result is partial reduction of magnesium oxide, that is, MgO changes the surface of magnesium, which will make the MgO powder black. Of course, nickel is used. Chromium wire is much better, because the affinity of chromium and oxygen is small, and the affinity of nickel and oxygen is also very small, so the MgO powder must be reduced, that is, the reduction temperature is much higher.
2. Increasing the compression density of MgO powder can reduce the working temperature of the resistance wire, but it is meaningless for annealing (referring to stainless steel 900 ℃) for the use of electricity, because the former has a temperature gradient, and the latter has temperature at various points equal.
3. Reducing the thickness of the insulating layer of the MgO powder can also reduce the working temperature of the MgO powder and increase the life of the heating tube.
4. Prevent the generation of organic matter and rust spots on the inner wall of the pipe. Therefore, the pipe, especially the iron pipe, must be pickled and dried to wipe the rust. After the process is completed, the pipe is quickly filled with powder and must not be left for too long. Especially in the high temperature season to avoid rust.
5. Since the MgO powder itself has organic matter that will cause the magnesium powder to turn black, it is recommended to roast the used MgO powder before filling the powder.
6. MgO powder or block should not be exposed to sun and night dew, let alone rain in the open air, so as to avoid acid rain and harmful gas from being immersed in the block and powder.
