There are many kinds of protective layer thickness of metal materials, as far as special-shaped springs are concerned, the plating process is generally used to obtain the protective layer thickness of metal materials. The thickness of the protective layer of electroplating process can not only maintain the corrosion, but also improve the appearance of the special-shaped spring. Some electroplating process metal materials can also improve the working characteristics of special-shaped spring, such as improving the surface compressive strength, improving the professional ability of anti-wear, improving the temperature resistance, preventing ray etching and so on. Customized special-shaped spring, but if it is simple to facilitate the etching of special-shaped spring, it should generally use pickling phosphating layer and plating process cadmium layer. Electroplating process nickel shaped spring zinc in the dry gas is more stable, most do not cause change, not easy to fade. When wet gas is converted into a layer of active zinc oxide or zinc carbonic acid milk white plastic film. This dense plastic film prevents further erosion. Therefore, the hot dip galvanized layer is used for the corrosion protection layer thickness of special-shaped spring under the general gas specification. Where and sulfuric acid, hydrochloric acid, anhydrous aluminum chloride and other solutions contact, as well as in the atmosphere of sulfur trioxide and other humid gases on the special-shaped spring, are not suitable for zinc plating.