The term "stainless steel" does not simply refer to one kind of stainless steel, but refers to more than one hundred kinds of industrial stainless steels, and each developed stainless steel has good performance in its specific application field. The key to success is to first understand the application and then identify the correct steel grade. There are usually only six steel grades relevant to building construction applications. They all contain 17-22% chromium, and the better steel grades also contain nickel. The addition of molybdenum can further improve the atmospheric corrosion resistance, especially the corrosion resistance to chloride-containing atmospheres.

Stainless steel is often divided into martensitic steel, ferritic steel, austenitic steel, austenitic-ferritic (duplex) stainless steel and precipitation hardening stainless steel according to the organizational state. In addition, it can be divided into: chromium stainless steel, chromium-nickel stainless steel and chromium manganese nitrogen stainless steel.