Anti-Rust Treatment Of Metal Welds
When many metal parts are in use, they need to be welded according to specific needs, but there are corresponding welds when the metal is welded. In order to prevent normal use between the metals, we need to carry out anti-rust treatment between the welds. According to the specific situation, the following are the methods of anti-rust treatment of metal welds.
1. During pickling, the acid in the crevices is not neutralized or the neutralization is incomplete, and the phosphating treatment turns into a film that is not complete and easy to rust. After a period of time after painting, the rust spread and overflowed the cracks.
2. Strong acid pickling, strong alkaline degreasing treatment. The agents remaining in the cracks have not been washed and cleaned after neutralizing each other. After roasting and drying, there is a white product in the crevices. After painting for a period of time, these white products. It reacts chemically with the corrosive medium in the air and overflows at the crevice.
Solution to the problem:
1. Degreasing must be weakly alkaline, and must not contain tablets of alkali. The TAL should be controlled at about 15 ℃, and the pH should not exceed 13.
2. Sulfuric acid can be used for pickling, and the pickling time should not be too long.It is best to use phosphoric acid.
3. After pickling, it is best to neutralize with 1~2 sodium carbonate.
4. It is best to use oxalic acid for surface adjustment, with a concentration of 1~2.
5. The acidity of zinc-based phosphating treatment should be subject to the upper limit. The concentration of impregnation treatment: TA: 35 or more, FA: 1.2 AC:8 (20CC fermentation tube).
6. All washing projects must be cleaned enough, and the water should be kept overflowing.
