Type of fastener surface treatment

Surface treatment is the process of forming a covering layer on the surface of a workpiece by a certain method. The purpose of the surface treatment is to give the surface appearance and anti-corrosion effect of the product. The surface treatment methods are all attributed to the following methods:

1. Electroplating: A part to be electroplated is immersed in an aqueous solution containing a metal compound to be deposited, and an electric current is passed through the bath to deposit and deposit the plated metal on the part. Generally electroplated with galvanized, copper, nickel, chromium, copper-nickel alloys, etc., sometimes boiled (blue), phosphatized, etc. are also included.

2. Hot-dip galvanizing: This is accomplished by immersing the carbon steel parts in a bath of dissolved zinc at a temperature of approximately 510°C. As a result, the iron-zinc alloy on the surface of the steel gradually becomes passivated zinc on the outer surface of the product. Hot dip aluminum plating is a similar process.

3. Mechanical plating: The surface of the product is impacted by the particles of the plated metal, and the coating is cold-welded to the surface of the product.

General screws are mostly electroplated, but they are used for hot-dip galvanizing in hexagonal wood screws such as electricity, highways, etc.; the cost of electroplating is generally 0.6-0.8 yuan per kilogram, and hot-dip zinc is generally 1.5-2 yuan/ Kilograms, the cost is higher.