Stainless steel can be classified into martensitic stainless steel, ferritic stainless steel, duplex stainless steel, austenitic stainless steel, and precipitation-hardening stainless steel.
Martensitic Stainless Steel: It is a type of stainless steel whose mechanical properties can be adjusted through heat treatment. It is a hardenable stainless steel. It is mainly used for steam turbine blades, cutlery, and surgical instruments.
Ferritic Stainless Steel: It contains chromium ranging from 15% to 30% and has a body-centered cubic crystal structure. This type of steel generally does not contain nickel and has characteristics such as high thermal conductivity, low coefficient of expansion, good oxidation resistance, and excellent stress corrosion resistance. It is mostly used for manufacturing parts that are resistant to corrosion by atmospheric conditions, water vapor, water, and oxidizing acids.
Duplex Stainless Steel: It refers to stainless steel with approximately 50% ferrite and 50% austenite, and generally, the lower content should not be less than 30%.
Austenitic Stainless Steel: Austenitic stainless steel refers to stainless steel with an austenitic structure at room temperature. Austenitic stainless steel is non-magnetic, has high toughness and plasticity, but relatively low strength. It cannot be strengthened through phase transformation and can only be strengthened through cold working.
Precipitation Hardening Stainless Steel: It refers to a type of high-strength stainless steel that is obtained by adding different types and amounts of strengthening elements to the chemical composition of stainless steel. Through the precipitation hardening process, different types and amounts of carbides, nitrides, carbonitrides, and intermetallic compounds are precipitated, which enhances the strength of the steel while maintaining sufficient toughness. This type of stainless steel is abbreviated as PH steel.
