Why should steel pipe be anticorrosive

The treatment quality of the main base of the steel pipe directly affects the adhesion quality and anti-corrosion effect of the anti-corrosion layer. At present, the commonly used methods for basic treatment include jet rust removal, tool rust removal, chemical rust removal and flame rust removal. The commonly used methods on site are mainly jet rust removal and tool rust removal. The quality of the base treatment should meet the requirements of the quality grade of rust removal in the construction of anticorrosive materials. In the "rust grade and rust grade of steel surface before coating" GB/T8923 standard, the quality grade of jet rust removal is divided into mild jet rust removal (Sal), thorough jet rust removal (Sa2), very thorough jet rust removal (sa2%) and the steel surface clean jet rust removal (Sa3) four kinds, Quality levels of tool derusting were divided into thorough hand and power tool derusting (St2) and very thorough hand and power tool derusting (St3).
The anti-corrosion principle of steel pipe is very simple, is to make full use of the stability of tin to cut off the corrosion medium and steel contact, to the purpose of anti-corrosion, its anti-corrosion mechanism and paint barrier. However, the anti-corrosion mechanism of galvanized steel pipe is different from that of galvanized steel pipe.
It is very important to keep the integrity of the coating. If the coating is scratched through the iron base, it is easy to rust and corrosion. This requires the coating to be thick enough to withstand a certain scratch, friction, if the coating is scratched to the damage of the iron substrate, the need for timely paint protection, otherwise corrosion, will rust the iron substrate below the tin layer, and the tin coating is intact, corrosion to a certain extent, the tin layer will fall off.
The composition of steel is mainly iron (Fe) containing a certain amount of carbon (C), in the air exposure is easy to be oxidized by oxygen in the air, and the formation of iron oxide (Fe2O3) ferric oxide, is a brown red substance, commonly known as rust, and the air also contains nitrogen oxides, such as NO2, the composition of the air in the water will become weak acid, Chemical reactions with the surface of the steel pipe will corrode the steel pipe, slowly, the material thickness of the steel pipe will be lost, if used in engineering, there may be leakage, fracture, softening and so on, so the preservation of the steel pipe to anti-corrosion.