Four common types of stainless steel wire mesh classification, characteristics, chemical types

Four common types of stainless steel wire mesh classification, characteristics, chemical types

Austenitic stainless steel: stainless steel square tube with austenitic structure at room temperature. When the steel contains about 18% Cr, 8%~10% Ni, and about 0.1% C, it has a stable austenitic structure. Austenitic chromium-nickel stainless steel includes the famous 18Cr-8Ni steel and the high Cr-Ni series steel developed on this basis by increasing the 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 has low strength. It is impossible to strengthen it through phase transformation and can only be strengthened through cold working.

If elements such as S, Ca, Se, and Te are added, it has good machinability. In addition to being resistant to corrosion by oxidizing acid media, this type of steel can also resist corrosion by sulfuric acid, phosphoric acid, formic acid, acetic acid, urea, etc. if it contains elements such as Mo and Cu. If the carbon content in this type of steel is less than 0.03% or contains Ti and Ni, its intergranular corrosion resistance can be significantly improved. High-silicon austenitic stainless steel has good corrosion resistance to nitric acid. Due to its comprehensive and good comprehensive properties, austenitic stainless steel has been widely used in all walks of life.

Ferritic stainless steel: stainless steel with ferrite as the main structure when in use. The chromium content is 11%~30%, and it has a body-centered cubic crystal structure. This type of steel generally does not contain nickel, and sometimes 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 manufacture parts resistant to atmospheric, water vapor, water and oxidizing acid corrosion. This type of steel has the disadvantages of poor plasticity, significantly reduced plasticity and corrosion resistance after welding, which limits its application. The application of out-of-furnace refining technology (AOD or VOD) can greatly reduce interstitial elements such as carbon and nitrogen, so this type of steel is widely used.

Austenite-ferrite duplex stainless steel: It is a stainless steel with about half austenite and half ferrite. In the case of low C content, the Cr content is 18%~28%, and the Ni content is 3%~10%. Some steels also contain alloying elements such as Mo, Cu, Si, Nb, Ti, and N. This type of steel has the characteristics of both austenite and ferrite stainless steel. Compared with ferrite, it has higher plasticity and toughness, no room temperature brittleness, and significantly improved intergranular corrosion resistance and welding performance. At the same time, it also maintains the 475℃ brittleness and high thermal conductivity of ferrite stainless steel, and has the characteristics of superplasticity. 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 resistance and is also a nickel-saving stainless steel.

Martensitic stainless steel: Stainless steel whose mechanical properties can be adjusted by heat treatment. In layman's terms, it is a type of hardenable stainless steel. The typical grade is Cr13, such as 20Cr13, 30Cr13, 40Cr13, etc. After quenching, the hardness is high, 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 two categories: martensitic chromium steel and martensitic chromium-nickel steel. According to the difference in organization and strengthening mechanism, it can also be divided into martensitic stainless steel, martensitic and semi-austenitic (or semi-martensitic) precipitation hardening stainless steel, and martensitic aging stainless steel.