Vacuum requirements and corrosion resistance of stainless steel flanges By yaang.com

The corrosion of stainless steel flange, is usually characterized by the thinning of the wall of the stainless steel flange, a partial pits and pitting. Stainless steel flange corrosion detection method is the method of magnetic flux leakage and ultrasonic test. Stainless steel flange has its rubber sealing, vacuum seal main metal seal and magnetic fluid seal. Among them, the metal seal can satisfy the requirement of ultra high vacuum, but has the following disadvantages: metal sealing ring elasticity bad, takes a lot of seal. Repeated use is very poor; The roughness of the flange sealing surface and edge and with high accuracy; Seal and flange material thermal expansion coefficient difference is bigger, easy to cause local deformation caused by the leakage.

The thermal expansion coefficient of the stainless steel pipe is similar to the copper pipe., is 1.5 times that of ordinarystainless steel pipe compared with stainless steel flange. pipe fitting has the characteristics of slow heat bilges cold shrink. Stainless steel is generally not local corrosion, chloride content of the resistance of 304 stainless steel can be up to 304 PPM, chloride content of the resistance of 316 stainless steel can be up to 316 PPM, this conclusion is based on exposure experiment data which has been confirmed by experience.

The corrosion resistance of the stainless steel flanges in all kinds of stainless steel pipes are the best. Because stainless steel flanges can passivation with oxidant, in the density of surface forming a layer of tough rich chromium oxide film Cr2O3, effective to prevent further oxidation reaction to occur. Will not happen like carbon steel, stainless steel flange uniform corrosion, when used without protective coating.

Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)