It has to be said that rust water leakage often occurs after pickling and phosphating in sheet metal processing, which is a common problem in many sheet metal processing. So how to prevent rust and solve this problem? At first, everyone needs to find the reason for this situation to analyze.
1. During pickling and passivation, the acid in the crevice is not neutralized or not completely neutralized. The phosphating treatment turns into an incomplete film and is easy to rust. After painting, the rust will spread to the crevice for a period of time.
2. Strong acid pickling passivation, strong partial alkali degreasing treatment, after the drug remaining in the gap is neutralized due to chemical interaction, many manufacturers do not clean the drinking water clean and tidy, which leads to the above gap after drying treatment. There is a milky white reactant. After painting for a period of time, this milky white reactant and the erosive chemicals in the vapor cause some kind of chemical reaction in the overflow gap. This difficulty is mostly caused between March and December. . And everyone's solution to the difficulty of preventing rust in sheet metal processing means the following:
1. Deoiling should use weak partial alkali as far as possible. It must not contain the active ingredient of flake alkali. TAL should be controlled at about 15POINT, and PH should not exceed 12.
2. For the step of pickling and passivation, sulfuric acid pickling and passivation can be used. The pickling and passivation time is better and not too long. It is just right to use ammonium sulfate.
3. After pickling and passivation, please use 1~2 potassium carbonate to neutralize.
4 For surface adjustment, it is better to use analytical chemicals such as sulfuric acid, and use the concentration value of 1 to 2 degrees.
5. The acid value of zinc-based phosphating treatment should be limited, and try to treat with dipping material: TA: 45 up and down, FA: 1.3 AC: 8 (20cc alcohol tube).
6. All hand-washed construction projects must not be cleaned and tidy, and hand-washed should be kept in overflow.
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