Straight seam pipe is formed by the surface layer of ultra-thin and very solid and stable chromium-rich oxide film (protective film), to prevent the continued infiltration of oxygen atoms, continue oxidation, and corrosion resistance. Once for some reason, the film was continuously damaged, the air or liquid oxygen atoms will continue to infiltrate or continuous separation of iron atoms in the metal, the formation of loose iron oxide, the metal surface will also continue to rust. This surface film is damaged in many forms, more common in everyday life are the following:
1. Straight seam pipe surface deposit with deposits of other metal elements of dust or heterogeneous metal particles in the humid air, the condensate between the attachment and stainless steel, the two connected into a micro-battery, triggering the electricity Chemical reaction, protective film damaged, called electrochemical corrosion.
2. Straight seam pipe surface adhesion of organic juice (such as vegetables, noodles soup, sputum, etc.), in the case of water oxygen, organic acids, organic acids for a long time on the metal surface corrosion.
3. Straight seam steel surface adhesion with acid, alkali, salt substances (such as the renovation of the wall of the alkali water, lime splashing), causing local corrosion.
4. In polluted air (such as a large amount of sulfide, carbon dioxide, nitrogen oxides in the atmosphere), the case of condensate, the formation of sulfuric acid, nitric acid, acetic acid point, causing chemical corrosion.
