According to its organizational structure, stainless steel is divided into austenitic stainless steel, ferritic stainless steel, duplex stainless steel, martensitic stainless steel and precipitation hardening stainless steel.

1. Austenitic stainless steel

Austenitic stainless steel is the most important type of stainless steel, and its output and consumption account for 70% of the total amount of stainless steel. According to the alloying method, austenitic stainless steel can be divided into two categories: chromium-nickel steel and iron-chromium-manganese steel. The former uses nickel as the austenitizing element and is the main body of austenitic steel; the latter uses manganese and nitrogen instead of expensive nickel to save nickel.

Generally speaking, austenitic steel has good corrosion resistance, good comprehensive mechanical properties and process properties, but low strength and hardness.

2. Ferritic stainless steel

Ferritic stainless steel contains 11%-30% chromium, and basically does not contain nickel. It is a nickel-saving steel type, and its structure is mainly ferrite in use.

Ferritic stainless steel has high strength, low cold work hardening tendency, excellent local corrosion resistance such as chloride stress corrosion, pitting corrosion, and crevice corrosion, but is sensitive to intergranular corrosion and has poor low temperature toughness.

3. Duplex stainless steel

It is generally believed that there is more than 15% ferrite on the austenite matrix, or more than 15% austenite on the ferrite matrix can be called austenite + ferrite duplex stainless steel.

Duplex stainless steels combine the advantages of austenitic and ferritic steels.

4. Martensitic stainless steel

Martensitic stainless steel is a kind of steel whose properties can be adjusted by means of heat treatment, and has high strength and hardness.

Five, precipitation hardening stainless steel

Precipitation-hardening stainless steel is a steel that precipitates carbides in steel by means of heat treatment, thereby achieving the purpose of improving strength.