During use, due to the influence of air and the environment, a black substance may appear on the surface, which requires blackening treatment. Blackening treatment is actually a process of heat treatment for metal objects such as stainless steel. After treatment, an oxide film forms on the surface to achieve the purpose of anti-corrosion and rust prevention. After the heating treatment, the wear resistance of the heater surface is improved, the surface hardness is increased, and it does not affect the internal components of the electric heater.
Under normal working conditions, the simplest method for blackening the surface of an electric heater involves the following steps:
1. First, clean the surface of the metal tube to keep it clean;
2. Second, perform degreasing treatment on the surface. This process can completely immerse the metal tube in the degreasing solution. The pH value of the degreasing solution should preferably be around 13, and the time should not be less than half an hour. After degreasing, rinse with clean water.
3. Next, pickling can be carried out. The pH value of the pickling solution is around 3, and the treatment time should not exceed 10 minutes. After pickling, rinse with clean water;
4. Blackening treatment: the pH value of the bath solution is between 2-4, the treatment time is around 10 minutes, and after blackening, it must be thoroughly cleaned;
5. Finally, dry and apply oil;
