Stainless steel is often divided into martensitic steel, ferritic steel, austenitic steel, austenitic ferrite (duplex) stainless steel, and precipitation hardening stainless steel according to their structural state. Stainless steel is the abbreviation for stainless steel and acid resistant steel. Steel that is resistant to weak corrosive media such as air, steam, water, or has rust resistance is called stainless steel.

Carbon steel is steel, but not pure steel, as it is more prone to oxidation and rust due to the absence of other alloying elements. The higher the carbon steel content, the greater the hardness, and the higher the strength, which is relatively lower in plasticity. It is usually used on metal parts that require strength, hardness, and wear resistance, such as cutting tools, steel cables, piano wires, springs, and cutting tools. After processing, the parts usually need to be further processed and tempered. The higher the carbon content of steel, the higher its hardness, strength, and wear resistance after heating treatment. Carbon steel is divided into high carbon steel, medium carbon steel, and low carbon steel, each of which is further divided into two types; According to its characteristics, high carbon steel is hard and brittle, while low carbon steel is soft and ductile.