Austenitic stainless steel refers to stainless steel with an austenitic structure at room temperature. When the steel contains about 18% Cr, 8%-10% Ni, and about 0.1% C, it has a stable austenite structure.

Austenitic 304 stainless steel is a very common stainless steel, also known as 18/8 stainless steel in the industry. On the basis of this stainless steel, a high Cr-Ni series steel developed by adding Cr and Ni content and adding Mo, Cu, Si, Nb, Ti and other elements.

Austenitic stainless steel is non-magnetic and has high toughness and plasticity, but its strength is low. It is impossible to strengthen it through phase transformation. It can only be strengthened by cold working. If elements such as S, Ca, Se, Te, etc. are added, it has good properties. Machinability. Therefore, it is widely used in industry and furniture decoration industry and food and medical industry.

Stainless steel whose mechanical properties can be adjusted by heat treatment is, in layman’s terms, a type of hardenable stainless steel. Typical grades are Cr13 type, such as 2Cr13, 3Cr13, 4Cr13, etc. After quenching, the hardness is higher, and different tempering temperatures have different strength and toughness combinations. It is mainly used for steam turbine blades, tableware, and surgical instruments.

According to the difference in chemical composition, martensitic stainless steel can be divided into martensitic chromium steel and martensitic chromium-nickel steel.

According to the different structure and strengthening mechanism, it can be divided into martensitic stainless steel, martensitic and semi-austenite (or semi-martensitic) precipitation hardening stainless steel and maraging stainless steel.

Ferritic stainless steel (400 series) contains 15% to 30% chromium and has a body-centered cubic crystal structure. This type of steel generally does not contain nickel, and sometimes also contains a small amount of Mo, Ti, Nb and other elements. This type of steel has the characteristics of large thermal conductivity, small expansion coefficient, good oxidation resistance, and excellent stress corrosion resistance. It is mostly used to make atmospheric resistance. , Water vapor, water and oxidizing acid corroded parts.

The price of ferritic stainless steel is not only relatively low and stable, but also has many unique characteristics and advantages. It has been proved that in many application fields where it was originally believed that only austenitic stainless steel (300 series) could be used.

Ferritic stainless steel is an excellent alternative material. Ferritic stainless steel does not contain nickel. The main elements are chromium (>10%) and iron. Chromium is a particularly corrosion-resistant element for stainless steel, and its price is relatively stable.

Precipitation hardening stainless steel is a type of stainless steel with high strength, high toughness and high corrosion resistance by adding hardening elements individually or in combination in various types of stainless steel.

Precipitation hardening stainless steel has comprehensive properties such as high strength, high toughness, high corrosion resistance, high oxidation resistance and excellent formability and weldability.

It is widely used in cutting-edge industries and civil industries. For example, the typical precipitation hardening stainless steel 17-4P can be used to make structures below 370°C that require corrosion resistance, wear resistance, and high strength.

Duplex Stainless Steel (DSS) refers to stainless steel with ferrite and austenite each accounting for about 50%. Generally, the content of less phases needs to be at least 30%. In the case of low C content, the Cr content is 18% to 28%, and the Ni content is 3% to 10%. Some steels also contain alloying elements such as Mo, Cu, Nb, Ti, and N.

This type of steel has the characteristics of austenitic and ferritic stainless steel. Compared with ferrite, it has higher plasticity and toughness, no room temperature brittleness, and significantly improved intergranular corrosion resistance and welding performance, while still maintaining iron The 475℃ brittleness, high thermal conductivity, and superplasticity of element stainless steel. Compared with austenitic stainless steel, it has high strength and significantly improved resistance to intergranular corrosion and chloride stress corrosion. Duplex stainless steel has excellent pitting corrosion resistance and is also a nickel-saving stainless steel.

Its main feature is that the yield strength can reach 400-550MPa, which is twice that of ordinary stainless steel, so it can save materials and reduce equipment manufacturing costs. In terms of anti-corrosion, especially in the harsh medium environment (such as sea water, high chloride ion content), the pitting corrosion, crevice corrosion, stress corrosion and corrosion fatigue performance of duplex stainless steel is significantly better than ordinary austenite Stainless steel is comparable to high-alloy austenitic stainless steel.