Metal stamping parts are the mechanical foundation parts with a large amount of use, which are used in almost all industries. Roll plating process is generally used in the production of electroplated metal stamping parts. Hot dip galvanizing (or hot-dip galvanizing for short) is a method to dip the plated metal stamping parts into liquid metal zinc or its alloy with low melting point for coating.
Hot dip galvanizing of metal automobile stamping parts mostly adopts flux method. Before the cleaned steel parts are immersed in the plating pot, a flux layer is formed on the surface to prevent oxidation and further remove the surface residues. During the process of immersion, the flux layer is volatilized by heat, which makes the fresh steel surface contact with the molten metal directly, and then infiltrates, dissolves, reacts and diffuses. The alloy layers of γ phase, δ 1 phase and ζ phase are formed on the steel surface in sequence, and a layer of molten metal zinc is attached. After cooling, the η phase zinc plating layer is formed.
Hot dip galvanized coating is a kind of low cost and good corrosion resistance coating. Due to the electrochemical characteristics of zinc, it has a "sacrificial" protection effect on the steel matrix, while the corrosion products (basic zinc carbonate) of zinc layer in the atmosphere are relatively dense, well attached and insoluble in water, which has a certain protection effect on the zinc layer. Therefore, hot-dip galvanizing is widely used to protect steel and its parts from atmospheric corrosion, especially suitable for mass production of standard parts and metal stamping parts.
Advantages of electro galvanizing for metal stamping parts:
1. The coating is even and bright. After passivation, various colors can be obtained and the decoration effect is good.
2. Low cost and simple operation.