In all applications of stainless steel, stainless steel screws are a very inconspicuous but closely linked way of application. The stainless steel is a very excellent alloy metal.
There are three main types of metal corrosion and usually can approach are composition design of contact surface of metal and metal dielectric properties, its application environment and external medium, change the stainless steel itself, if you want to use the complete corrosion resistance of stainless steel to produce stainless steel screws, unless special application requirements, or from the angle of economy it is not cost-effective nor practical, and put the screws on the surface and easy to cause the corrosion of the environment medium complete isolation, the feasibility is very low.
Improve the composition structure of stainless steel can increase the corresponding resistance in some situations, but as the application of less ordinary stainless steel screws basically is not taken in the optimization of steel components to meet the demands for use, and even if the optimization cannot completely screw can meet the diverse and harsh environment of demand.
Therefore, for stainless steel screws, the most widely used and the most suitable corrosion resistance method is to make surface treatment of the material.
Stainless steel screw surface corrosion prevention technique refers to the use of various methods on the surface of stainless steel materials with common protective layer, and its role is to isolate the metal medium environment and corrosion resistance from the formation to suppress the corrosion process, or reduce the corrosive medium and the stainless steel material surface contact degree, so as to avoid or the purpose of reducing corrosion.
The requirements for the protection layer of the stainless steel screw surface are required as described below. The first is to have good corrosion resistance, wear resistance and high hardness. Secondly, the structure of the stainless steel material used is dense, perfect and small pore. The third point is that both the surface protection layer and the matrix metal should be separated and have good bonding force. The last point is that the surface protection layer should be spread evenly and with a certain thickness.
The surface protection layer of stainless steel usually includes two kinds of metal coating and non-metallic coating. The metal coating means the metal or alloy with strong corrosion resistance is used as the protective layer on the stainless steel surface, and the coating is also called the coating. There are many ways to produce metal coating, the most commonly used is electroplating, then molten metal plating and chemical surface treatment.
Instead of metal coating refers to the use of organic polymer materials such as paint or inorganic material such as ceramic, forming a protective layer on the surface of stainless steel material, the protective layer can be stainless steel and the external environment medium is completely isolated, also can effectively prevent the substrate from corrosion of stainless steel.
Source: China Stainless Steel Screws Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)