Screw Corrosion Prevention

Screw Corrosion Prevention

Screw Corrosion Prevention

Metal by the environment, by chemical or electrochemical reaction resulting from the devastating assault, known as corrosion, almost all metal products, in a certain environment, will have some type of corrosion, and metal screws are naturally can not avoid the problem of metal corrosion, the use of the environment and the time is not the same time, the phenomenon of corrosion is also a significant difference. Many polluting industries, such as steel, petrochemicals, thermal power generation, etc. Together with the recent steam, locomotive substantial growth, a large number of emissions, 使 air is full of corrosive properties of Sulfide with nitrogen gas and particles, which are caused metal corrosion of the main reasons. For example, six light Mailiao Formosa Plastics plant, currently found in the screws, bolts, structural steel and pipes and other metal corrosion situation, the seriousness of the plant may have exceeded the original estimate before, the formation of engineers must pay attention and priority issues .

Corrosion of equipment will result in substantial maintenance costs and severe economic losses, as a result of corrosion to increase the design, manufacture, maintenance and repair cost, or even cases of damage and disaster. The most extensive use of screws, the maximum amount of demand, the corrosion resistance of the merits to determine its utility for durability, safety and reliability of the equipment have a significant impact, therefore Corrosion Prevention Methods Research, development and application of modern anti-corrosion technology , is an important subject.

Method of corrosion

Metal corrosion methods are mainly four aspects, namely, control of material itself, the use of the environment, materials and environment interface, and improved the design of metal structures, the use of a completely corrosion resistant alloy to produce screws, unless there are special needs, or in the economic point of which are unrealistic, or the surface of the screw corrosive environmental factors participants complete isolation, in practice, does not seem feasible, may be very difficult. Improved metal structure designed to improve in some circumstances the effect of the special situation, but most of the design of the screw can not be fully modified, and its protective effect is not permanent, therefore this method can not solve the problem, only at the interface of corrosion , that is, anti-corrosion surface treatment is the most widely used method.

Surface corrosion is the use of various methods of dealing with the metal surface to exert protective layer, its role is to separate metal and corrosive environment, in order to inhibit the corrosion process, produce, or reduce the corrosive medium with the metal surface contact, and to prevent or the purpose to reduce corrosion. Protective layer should be able to meet the following requirements: 1. Corrosion, wear, high hardness, 2. Structure, the integrity, porosity, 3. And matrix metal-binding solid, good adhesive force, 4. Uniformly distributed and have a certain thickness. Protective layer is usually divided into two types of metal coatings and non-metallic coating, metal coating is stronger with the corrosion resistance of the metal or alloy corrosion in the metal surface easily forms a protective layer, such coating is also called coating. The method of metal plating and types of large, one of the most common is electroplating method, followed by the molten metal dip method (hot dip), and chemical surface treatment.

Non-metallic coating is the use of organic polymer materials such as paint, and inorganic materials such as ceramics, metal equipment or parts to form the surface protective layer, the protective layer can base metals and environmental media completely isolated to prevent contact with the base metal due to corrosion medium caused by corrosion.