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How to choose magnesium powder for electric heating elements？
Table of Contents
According to the heating method of electric heating element:
1. If dry-burning in the air, generally use a high-temperature powder series or a high-temperature-resistant and moisture-proof powder series.
2. If heated in water, heavy silicon-modified powder is generally used. If dry burning experiments are required under test conditions, the high-temperature resistant and moisture-proof powder series can be used.
3. For some electric heating tubes, the empty tube is pre-heated to green black, and shiny. For oven-type electric heating tubes, it is best to use high-temperature resistant and moisture-proof powder and medium-temperature powder series.
4. If there is a heating pipe with 1050-degree high-temperature heat treatment, different types of high-temperature powder series can be selected according to the surface load and the length of the pipe. And don’t choose to change your profile again.
Select magnesium powder according to the working temperature powder, that is, the surface load：
1. Choose low-temperature powder or medium-low-temperature powder below 6W.
2. Choose medium-temperature powder below 8W.
3. Choose medium and high temperature powder below 9W.
Non-air fired electric heating element
Strong convection and contact thermal conductive electric heating elements such as copper, aluminum, Bundy or stainless steel tubes:
1. Copper pipes are mainly water-fired pipes
There are many spiral shapes, and some are heat treated for a short time in order to bend. The heat treatment temperature ranges from 500-660 degrees.
This kind of pipe requires moisture-proof ability and modified magnesium powder that has good thermal conductivity but has little requirement for dry burning leakage current.
Therefore, low-temperature powder series products of medium or above are needed. If there is no heat treatment and only 250-350 moisture removal, the grade of magnesium powder can be appropriately reduced.
2. Aluminum tubes mainly use contact heat conduction
Mainly die-cast horseshoe tubes or other types of aluminum tubes.
Due to the low hardness of aluminum tubes, the density of magnesium powder is very high. It is best to provide samples with high density products.
Some types of aluminum tube manufacturing processes include brazing processes. This type of tube requires good moisture resistance and modified magnesium powder that has good thermal conductivity but does not require high dry burning leakage current.
Therefore, low-temperature powder series products are needed. If there is no heat treatment and only 250-350 moisture is released, the grade of magnesium powder can be appropriately reduced.
3. BUNdy Bundy tube
It is also called copper-plated iron pipe. The main feature of this kind is that it solves the problem of iron pipe being placed for a short period and easy to rust.
It mainly produces bread machine tubes and other products with embedded thermal conductivity. Therefore, low-temperature powder products are mostly used.
4. Strong convection such as stainless steel pipes
What it actually refers to is that the electric heating tube is empty-fired on the surface, but the temperature of the tube surface is quickly reduced due to the use of strong air flow.
The temperature that magnesium powder withstands is not too high, and it is basically not much different from the temperature when heated in water.
This kind of electric heating has high requirements for strong air flow. If the temperature cannot be cooled down quickly, it will easily cause problems such as pipe melting or explosion.
5. Contact heat conduction
In fact, the electric heating tube is embedded in the workpiece that needs to be heated. Since the heating mesons are different, it is generally understood as a hot water channel, instant heater, etc.
Most of these products can be low-temperature powder products, but for some products such as abrasive heaters, you need to ask the customer’s specific work questions.
Some are lower than 700 degrees and require moisture-proof capabilities, so the medium-temperature powder series of high-temperature and moisture-proof magnesium oxide products are often used, while some products require the use of high-temperature tubes.
6. Industrial heating tube
Most of them are dry-fired pipes. Since the length of the pipe and the problems of using the pipe are quite different, medium-temperature powder and high-temperature powder products are mostly used.
It also requires high-temperature powder light silicon treatment products to have some moisture-proof capabilities.
