How much do you know about the common surface treatment of self tapping screws

The common surface treatments of self-tapping screws are: electroplating, anodizing, passivation, electrophoresis, blackening (blue) and dacromet, etc.

1. Electroplating is to be electroplated self-tapping screw as the cathode soaked into the solution containing metal cations to be electroplated, through the action of the metal attached to the surface of Yin and commonly used electroplating metal nickel, chromium, tin, copper, gold and silver.

2. Anodizing is the use of chemical or electrochemical treatment, so that a metal surface containing the metal composition of a skin film. Most metal materials (such as stainless steel, zinc alloy, aluminum alloy, copper alloy, titanium alloy) can be in the appropriate electrolyte for Yang and oxidation treatment.

3. Blackening, generally using alkaline chemical oxidation method, because of the appearance of the characteristics of the oxide film, can only be used in the general situation or oily medium, or taking into account the effect of the appearance, the screw will be blackened.

4. Passivation is to dissolve the iron pollutants hidden on the screw, so that the surface of the self-tapping screw open into a layer of passivation protective film, can protect the screw is not easy to be corroded, general passivation surface treatment method applied to electronic products.

5. Electrophoresis is to evenly cover paint, rubber and other particles on the surface of screw fasteners. After surface treatment by electrophoresis, the coating on the screw surface should be uniform, flat and smooth.

6. Dacromet surface treatment can be plated in three colors, black, silver gray, silver white. The advantage of Dacromet surface treatment is that rust - proof west can be good, suitable for the material of carbon steel and stainless steel.