Because the stainless steel pipe fittings in the chloride ion more widespread and corrosive medium environment, will destroy the surface passivation membrane, and formation of corrosion pits, combined with the surface of the part of the inclusions, poor chrome area, grain boundary and dislocation, the stainless steel surface is very susceptible to corrosion, form the rusty spot, make lose luster, around stainless steel produced by corrosion. Therefore, use the environment as much as possible, reduce the content of chlorine ions, keep the space clean and dry, and reduce the dust adhesion. If you are in a coastal city, a humid space, and a lot of chlorine ions, then choose 316 or 316L materials that are resistant to corrosion, to reduce the erosion of chloride media.
The conditions that lead to the corrosion of stainless steel cracks are more extensive. Most corrosive media will cause crevice corrosion in the stainless steel pipe. Such as rain, water vapor condensate chlorine ion will produce crevice corrosion, especially in the cracks are very small, oxygen, it is hard to get into local often appears crevice corrosion, such as water supply pipe flange, screw between links and links with other different materials, easy to produce crevice corrosion.
When two types of metal with different potential potential energy are different, the contact between steel and stainless steel can produce potential difference and can be corroded easily.
What are the measures and countermeasures to avoid corrosion of stainless steel pipe fittings?
The first is to prevent it in the production process. In stainless steel pipe production enterprises, considering the safety and to prevent the corrosion of the pipe fittings in use factor, in the processing of stainless steel pipe fittings must take solid solution treatment, the heat treatment is very important.
Second stainless steel pipe fittings in the welding and solid solution to ensure that the use of gas, because in the welding process and solid solution treatment process, using gas can greatly enhance stainless steel pipe welding seam and the corrosion resistance of the stainless steel body, thereby greatly enhancing the service life of the stainless steel tube products.
Solid solution is an important measure to improve the application and anti-corrosion of stainless steel pipe fittings. The solid solution process can improve the processing cost, but also enhance the safety factor.
Pipeline design prevention. In the process of pipeline design, not only to minimize crevice corrosion, but also reduce the construction site welding, really need to welding the first order processing, after gas protection and reduce the damage to the aperture passivation layer, the other is the installation environment is bad, there is water vapor, easily able to consider using the viega profi-press connection mode, to avoid the generation of cracks.
The fourth installation construction process prevention. Corrosion resistance of stainless steel is not absolute, but relative, conditional requirement, under adverse factors and conditions stainless steel can also be corroded. Therefore, it is necessary to maintain a clean and dry environment during installation, so as to avoid moisture accumulation, which can prolong the service life of products. Followed by the construction and installed to prevent the residual grinding wheel for cutting the foam in the stainless steel tube, welding oxide and carbon powder production of corrosive medium, such as the layer to minimize the grinding wheel for cutting of stainless steel metal structure damage, prevent to produce a variety of corrosion.
Source: China Stainless Steel Pipe Fittings Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)