The corrosion resistance of stainless steel tubing depends on the content of chromium. When the amount of chromium is added up to 10.5%, the atmospheric corrosion resistance of steel increases remarkably. When the content of chromium is higher, the corrosion resistance can be improved, but it is not obvious. The reason is that alloying of steel with chromium changes the type of surface oxide to a surface oxide similar to that of pure chromium metal. This close adhesion chromium oxide protects surface, and prevent further oxidation. This oxide layer is extremely thin, through it you can see the natural burnish of stainless steel surface, make the stainless steel has unique surface. Moreover, if the surface is damaged, the exposed steel surface will react with the atmosphere for self repair and reform the "passive film" and continue to play a protective role.