What are the Causes of Custom Sheet Metal Rusting? -

1. When pickling passivation, the acid at the seam is not neutralized or neutralized incompletely, and the pickling phosphate becomes a skin film incompletely and rusts easily. After spraying, rust will be scattered in the overflowing crevices.

custom sheet metal box — Custom Sheet Metal Box

2. strong alkali pickling passivation, strong alkali degreasing treatment, the remaining drug oxidation in the gap, many manufacturers do not have tap water finishing, dry gap formation milky generation, after spraying for a period of time, milky generation, gas corrosion material in the overflow gap to form a certain exothermic reaction, this problem often occurs.

The methods to avoid corrosion in sheet metal processing are as follows:

We must choose weak partial alkali degreasing, which cannot contain flake alkali components, TAL should be manipulated to 15POINT up and down, PH not more than 12.

Hydrochloric acid wash passivation can be used for the pickling passivation process. Pickling passivation time does not need to be too long. The use of ammonium sulfate is just right.After pickling passivation, please use for 1~2 sodium carbonate in the combination.Use organic chemicals such as hydrochloric acid and other organic chemical raw materials, the concentration value of 1 ~ 2 degrees. Zinc pickling phosphate acid value should be bundled, try prepreg: TA: about 45, FA: 1.3AC: 8 (20cc hair alcohol tube). Do not need to sort out the hand washing project, hand washing to keep the overflow.

Related Posts