Stainless steel is often divided into: martensitic steel, ferrite steel, austenitic steel, etc. In addition, it can be divided into chromium stainless steel, chromium nickel stainless steel and chromium manganese nitrogen stainless steel.
1. Ferritic stainless steel: 12-30% chromium. Its corrosion resistance, resistance and weldability are improved with the addition of chromium content, and its chloride stress corrosion resistance is better than that of other stainless steels. Crl7, cr17mo2ti, Cr25, cr25mo3ti and Cr28 belong to this category. Because of its high chromium content, ferritic stainless steel has good corrosion resistance and oxidation resistance, but poor mechanical and technological functions. It is mainly used in acid resistant structure with little stress and as anti-oxidation steel. This kind of steel can resist the corrosion of atmosphere and brine solution, and has the characteristics of good high temperature oxidation resistance and small thermal expansion coefficient. It can be used in food factory equipment, and can also be used to manufacture parts working at high temperature, such as gas turbine parts.
2. Austenitic stainless steel: it contains more than 18% chromium, about 8% nickel and a few molybdenum, titanium, nitrogen and other elements. It has good comprehensive function and can resist corrosion of various media. The common trademarks of austenitic stainless steel are 1Cr18Ni9, 0Cr19Ni9, etc. The WC & lt; percent of 0Cr19Ni9 steel is 0.08 and marked as "0" in the steel grade. This kind of steel contains a lot of Ni and Cr, which makes the steel austenite at room temperature. This kind of steel has outstanding plasticity, resistance to corrosion, weldability and corrosion resistance. It has good corrosion resistance in oxidizing and reducing media. It is used to manufacture acid resistant equipment, such as corrosion resistant containers and equipment lining, conveying pipes, resistant equipment parts, etc. The austenitic stainless steel is generally treated by solution treatment. The steel is heated to 1050-1150 ℃ and then cooled to obtain single-phase austenite arrangement.
3. Austenitic ferrite duplex stainless steel: it has the advantages of both austenitic and ferritic stainless steel, and has superplasticity. Stainless steel in which austenite and ferrite arrangements account for about half each. In the case of low C content, Cr content is 18-28%, Ni content is 3-10%. Some steels also contain Mo, Cu, Si, Nb, Ti, N and other alloy elements. This kind of steel has the characteristics of austenite and ferritic stainless steel. Compared with ferrite, this kind of steel has higher plasticity and resistance, no room temperature brittleness, and its intergranular corrosion resistance and welding function are significantly improved. At the same time, it also maintains the 475 ℃ brittleness of ferritic stainless steel, high thermal conductivity and superplasticity. Compared with austenitic stainless steel, it has high strength, intergranular corrosion resistance and chloride stress corrosion resistance. Duplex stainless steel has excellent pitting corrosion resistance and is also a nickel saving stainless steel.
4. Martensitic stainless steel: high strength, but poor plasticity and weldability. The common trademarks of martensitic stainless steel include 1Cr13, 3Cr13, etc. due to its high carbon content, it has high strength, hardness and wear resistance, but its corrosion resistance is slightly poor. It is used in some parts with high mechanical function requirements and general corrosion resistance function requirements, such as tension spring, turbine blade, hydraulic compressor valve, etc. This kind of steel is used after quenching and tempering.
Source: Jiangmen stainless steel plate http://www.jmdxbxg.com/index.html