In the production process of electric heating tubes, blackening treatment is sometimes used. The heat treatment is a process of heat treatment of metal objects such as stainless steel. After the treatment, there is an oxide film on the surface to achieve the purpose of anticorrosion and rust prevention. After the heat treatment, the wear resistance of the surface of the heating pipe is increased, and the hardness of the surface is improved, and the components inside the electric heating pipe are not affected.
Under the normal working conditions, the easiest way to blacken the surface of the electric heating tube is as follows:
1. First clean the surface of the metal tube and keep it clean;
2, the second is the surface of the degreasing treatment, this process can completely place the metal tube in the degreasing liquid. The pH of the degreased solution is preferably around 13, and the time is not less than half an hour. Wash off with water after degreasing.
3. Next, pickling can be carried out. The pH value of the pickling solution is about 3, the treatment time is not longer than 10 minutes, and the water is washed after pickling;
4. Blackening treatment: the concentration of the pool liquid is between 2-4, the treatment time is up to 10 minutes, and it is incomparably cleaned after blackening;
5, finally drying, oiling;
According to the above five points, the blackening treatment of the electric heating tube is a very effective method.