Stainless steel fasteners are also made of metal, and metal corrosion prevention methods mainly include four aspects, namely, the nature of the material itself, the use environment, the interface between data and environment, and the design of improved metal structures.
If stainless steel fasteners are made of complete corrosion-resistant alloys, unless there is a special need, it is unrealistic in terms of economic concept, or it is not feasible in practice to completely isolate the appearance of fasteners from the environmental factors that cause corrosion, which may be very difficult. Improving the design of metal structure can improve the impact of special circumstances under certain conditions, but most stainless steel fasteners can not be fully modified in design, and their maintenance role is not permanent, so this method can not basically deal with problems, as long as the anti-corrosion on the interface, that is, the surface anti-corrosion treatment is currently widely used.
Anti corrosion treatment of stainless steel fastener surface refers to the application of various methods to apply maintenance layer on the metal surface, which is used to isolate the metal from the corrosive environment to prevent the corrosion process, or reduce the contact between corrosive media and the metal surface, so as to avoid or reduce corrosion.
The stainless steel fastener maintenance layer shall meet the following requirements:
1. Corrosion resistance, abrasion resistance, high hardness
2. The structure is tight and intact with small pores.
3. Solid separation from the base metal and good adhesion.
4. It is evenly distributed and has a certain thickness.
The maintenance layer is usually divided into metal coating and non-metal coating. The metal coating refers to the maintenance layer made of metal or alloy with strong corrosion resistance on the metal surface that is easy to corrode. This kind of coating is also called coating. There are many methods and varieties for producing metal coatings, among which electroplating is the most common, followed by molten metal immersion (hot dip) and chemical surface treatment. The non-metallic coating refers to the maintenance layer formed on the surface of metal equipment or parts by using organic macromolecular materials such as paint and inorganic materials such as ceramics. The maintenance layer can completely isolate the base metal from the environmental medium and prevent the base metal from corrosion due to contact with the stainless steel standard parts.
