One, corrosion of stainless steel pipes
Corrosion occurs at the entire interface between the stainless steel pipe and the dielectric environment and is characterized by uniform thinning along the section, which occurs mostly in the acid and hot alkaline medium. Corrosion resistance of stainless steel pipes is often evaluated by corrosion rate (mm/a).
Two, stainless steel pipe corrosion reasons
Can not form a passivation film or passivation film instability and passivation membrane damage and can not timely repair; in the actual engineering application, the electrolyte in many corrosive environment, even if the stainless steel pipe is in a passive state, often at different speeds (sometimes very slowly) were dissolved; finally, the control equipment, components, stainless steel vessel thickness (or section) gradually thinning and failure.
Three, prevent stainless steel pipe corrosion measures
Choose the grade of corrosion resistance according to the kind, concentration, temperature and specific requirements of the corrosive medium. Then choose the appropriate stainless steel grade according to the corrosion resistance grade requirements.
Stainless steel pipe corrosion resistance when there are ten levels of standards. Choose which level to meet the requirements of anti-corrosion equipment, components, in addition to the length of life, the characteristics of equipment and components (thick, thin, big or small) and the product quality (color purity, impurities, etc.) are considered in the. For example, the use of the process, equipment, use components required to maintain smooth mirror or precise size and impurities, the purity of the product, the color has special requirements, generally 1 ~ 3 level standard; while the demand is not high, the maintenance is convenient or life is not very long, the equipment components, can use 4 ~ 6 grade standard. However, in normal circumstances, the standard greater than 6 is not selected.
The corrosion resistance of stainless steel pipes is actually evaluated by their corrosion rate in the medium. In this medium, the corrosion rate of the stainless steel pipe is corrosion resistant within the allowable range, but this is not corrosion free.
There are a lot of stainless steel pipe corrosion Handbook for reference, and the test data of stainless steel in a large number of practical medium for use, and there are a lot of practical engineering experience using stainless steel pipe, as long as we have the correct selection and reasonable use of stainless steel, stainless steel corrosion accident can be prevented. Generally speaking, in the practical application, the corrosion resistance of the stainless steel pipe to advance in the medium, the corrosion rate of stainless steel pipe, master the equipment under the reasonable use of the service life.
Source: China Steel Pipe Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)