However, there are national standards for stainless steel used in catering containers, which stipulate the migration amount under specific conditions. The allowable migration itself is far below the amount that may be harmful to health. The food in reality (such as tea) is far milder than the "specific conditions" in the national standard determination. Even if there is chromium precipitation, it is far from "harmful".
Stainless steel is the abbreviation of stainless and acid-resistant steel, and steel or stainless steel resistant to weak corrosive media such as air, steam and water is called stainless steel. Steel resistant to chemical corrosive media (acid, alkali, salt and other chemical corrosion) is called acid-resistant steel.
Their corrosion resistance is different due to their different chemical compositions. Ordinary stainless steel is generally not resistant to chemical medium corrosion, and acid-resistant steel is generally stainless. The word "stainless steel" refers not only to one kind of stainless steel, but to 100 kinds of industrial stainless steel, and each developed stainless steel has good performance in its specific application field. The key to success is to find out the purpose first, and then determine the correct steel grade. There are usually only six kinds of steel related to the application field of building construction. They all contain 17 ~ 22% chromium, and the better steel also contains nickel. Adding molybdenum can further improve the atmospheric corrosivity, especially the corrosion resistance to chlorine-containing atmosphere.