First, the choice of the material of the electric heating tube shell depends mainly on the heating medium, and the tube is required to have better corrosion resistance in the heating medium, thereby obtaining a long service life.
In our normal industrial equipment, the main thing is to heat water and air. The heating medium of this kind is the most widely used, such as stainless steel 304, stainless steel 321, stainless steel 316, stainless steel 310S, etc.
Electric heating tube stainless steel has many different grades, such as stainless steel 304, stainless steel 321, stainless steel 316L, stainless steel 310S and so on. Conventional non-alkaline water and oil can be heated with stainless steel 304. Some acid-alkaline liquids are made of stainless steel 316L, but strong acid and alkali are not suitable for stainless steel 316L. From the standpoint of temperature resistance, the general working temperature is Stainless steel 304 can be used around 300 degrees, stainless steel 321 is recommended for working temperature of about 500 degrees, and stainless steel 310S is recommended for higher temperatures. The above is purely personal experience, non-accurate theoretical values, for reference only.
Second, the choice of the material of the electric heating tube shell also needs to consider the temperature resistance
In fact, according to my personal summary, the material of the electric heating tube shell is mainly selected according to the following points:
1, the working environment
Heat the liquid or heat the air. If it is liquid, it is water or oil, or it is a corrosive chemical liquid. If it is air, whether it is vacuum or normal air or corrosive gas, these need to be considered.
2, working temperature
Temperature we need to consider two, one is the surface temperature of the heating tube, and the other is the temperature of the heating tube heating environment.
3. The situation of water quality
The poor water quality leads to scale and the effect of scale on the heating tube. We have analyzed it before. Then, for different water quality, we also need to consider the choice of shell material.
