During the use of electric heaters, due to the influence of air and environment, a black substance appears on their surface, which requires blackening treatment. Blackening treatment is actually a process of heat treatment for metal objects such as stainless steel. After treatment, a layer of oxide film forms on the surface to achieve the purpose of anti-corrosion and rust prevention. After heat treatment, the wear resistance of the heater surface is improved, the surface hardness is increased, and the internal components of the electric heater are not affected.
Under normal working conditions, the simplest method for blackening the surface of electric heaters 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 is preferably 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, and the treatment time is about 10 minutes. After blackening, clean thoroughly;
5. Finally, dry and apply oil;
