Types of Stainless Steel
Posted by may green on March 25th, 2020
The stainless steel is an important alloy widely applied in daily life and various industries. Through the CNC machining process, they can be machined to customized stainless steel parts with high precision and complex shapes, such as stainless steel CNC machining of cnclathing.com Stainless steel can not only be classified into 200 series, 300 series, 400 series, 500 series, 600 series, but also Austenitic, Ferritic or Duplex types as below.
Types of Stainless Steel
1. Austenitic stainless steel
Austenitic stainless steel refers to stainless steel with austenitic structure at room temperature. When the steel contains about 18% Cr, 8% ~ 25% Ni and about 0.1% C, it has a stable austenite structure. Austenitic stainless steel is non-magnetic and has high toughness and plasticity, but its strength is low, so it can not be strengthened by the transformation. It can only be strengthened by cold working. If s, CA, Se, TE, and other elements are added, it has good machinability.
2. Ferritic stainless steel
The chromium content of ferritic stainless steel (400 Series) is 15% ~ 30%, which has a BCC crystal structure. This kind of steel generally does not contain nickel, and sometimes contains a small amount of Mo, Ti, Nb, and other elements. This kind of steel has the characteristics of large thermal conductivity, small expansion coefficient, good oxidation resistance, excellent stress corrosion resistance, etc., and is mostly used to manufacture parts resistant to atmospheric, water vapor, water, and oxidative acid corrosion. 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 ferritic stainless steel is a very excellent alternative material in many applications that originally thought that only austenitic stainless steel (300 Series) could be used.
3. Martensitic stainless steel
High strength, but poor plasticity and weldability. The commonly used grades of martensitic stainless steel are 1Cr13, 3Cr13, etc. because of its high carbon content, it has high strength, hardness and wear resistance, but its corrosion resistance is slightly poor. It is used for some parts with high mechanical property requirements and general corrosion resistance requirements, such as spring, turbine blade, hydraulic compressor valve, etc. This kind of steel is used after quenching and tempering. Annealing is required after forging and stamping.
4. Duplex stainless steel
Duplex stainless steel (DSS for short) is characterized by both austenitic and ferritic stainless steel because it accounts for about 50% of ferrite and austenite respectively. In the case of low C content, Cr content is 18% ~ 28%, Ni content is 3% ~ 10%. Some steels also contain Mo, Cu, Nb, Ti, N and other alloy elements. Compared with ferrite, it has higher plasticity and toughness, no room temperature brittleness, significantly improved intergranular corrosion resistance and welding performance, and maintained 475 ℃ brittleness, high thermal conductivity and Superplasticity of ferritic stainless steel. Compared with austenitic stainless steel, it has higher 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.
5. Precipitation hardening stainless steel
Precipitation hardening stainless steel Steel) refers to a kind of high-strength stainless steel which is added with different types and quantities of strengthening elements on the basis of the chemical composition of stainless steel, and precipitates different types and quantities of carbides, nitrides, carbonitrides and intermetallic compounds through a precipitation hardening process, so as to improve the strength of the steel and maintain sufficient toughness.
Different stainless steel types and comparison:
https://bit.ly/2WGR5IP
