After heat treatment, it will increase the wear resistance and hardness of the outer surface of the heating tube, without affecting the components inside the heating tube. In the production process of electric heating tubes, there are special cases where blackening treatment is used. Heat treatment is a process of heat treatment for metal objects such as stainless steel. After treatment, there will be an oxide film on the surface to achieve the goal of corrosion prevention and rust prevention.
The simplest method for blackening the surface of electric heating tubes under normal working conditions is as follows:
1. Firstly, clean the surface of the metal tube to maintain cleanliness;
2. The second is to perform degreasing treatment on the surface, which can absolutely place the metal tube in the degreasing solution. The pH value of the degreasing solution should be around 13, and the time should not be less than half an hour. After defatting, rinse with clean water.
3. Next, acid washing can be carried out. The pH value of the acid washing solution is about 3, and the disposal time should be no more than 10 minutes. After acid washing, rinse with clean water;
4. Blackening treatment: The concentration of the liquid in the pool is between 2-4 pH, and the disposal time is about 10 minutes. After that, the blackening is extremely clean and tidy;
5. Finally, bake and oil;