Deal With Rust In Sheet Metal Machining?

Rust will seep out of sheet metal after phosphating, so this is a problem that many factories need to solve urgently. However, before we can understand the reasons for this phenomenon, we can take corresponding measures. There are two main reasons for rust:

• 1. The acid in the cracks during pickling is not neutralized or incompletely neutralized, and the phosphate film is not completely rusty, and the rust spreads out of the cracks for a period of time after painting.
• 2. Strong acid pickling, strong alkaline degreasing. The medicaments remaining in the crevices were neutralized with each other and washed without washing. After baking, white products were sewn out. These white products are painted for a while. It reacts with the corrosive medium in the air and overflows the gap.

• 1. For degreasing, use weak alkaline degreasing. Must not contain protopine. TAL should be controlled around 15POINT and ph cannot exceed 13.
• 2. Sulfuric acid can be used for pickling. Pickling time should not be too long. Phosphoric acid is recommended.
• 3. After pickling, neutralize with 1-2 sodium carbonate;
• 4. Surface adjustment is recommended to use oxalic acid, the concentration is 1-2;
• 5. The acidity of zinc phosphating treatment should take the upper limit. Dipping treatment concentration: above TA35, FA1.2AC8 (20CC fermentation tube)
• 6. It is not necessary to wash all water washing projects, and the water washing should keep overflow

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