Stainless steel is referred to as stainless steel, it is composed of stainless steel and acid steel two parts, in short, can resist atmospheric corrosion of steel called stainless steel, and can resist the corrosion of chemical media steel called acid steel. Generally speaking, chromium content Cr more than 12% steel has the characteristics of stainless steel according to the microstructure of stainless steel after heat treatment can be divided into five categories: ferritic stainless steel, martensitic stainless steel, austenitic stainless steel, austenitic - ferritic biphase stainless steel and precipitation hardened stainless steel.

Carbon steel is an iron carbon alloy with carbon content ranging from 0.0218% to 2.11%. Also known as carbon steel. It also contains small amounts of silicon, manganese, sulfur and phosphorus. The higher the carbon content of general carbon steel, the greater the hardness, the higher the strength, but the lower the plasticity.