What are the main types of stainless steel?

 Stainless steel is often divided into martensitic steel, ferrite steel, austenitic steel, austenite-ferrite (duplex) stainless steel and precipitation hardening stainless steel. In addition, can be divided into: chromium stainless steel, chromium nickel stainless steel and chromium manganese nitrogen stainless steel. Also used for pressure vessels with special stainless steel "GB24511_2009_ pressure equipment with stainless steel plate and steel belt".

Containing chromium 15% ~ 30%. Its corrosion resistance, toughness and weldability improve with the increase of chromium content, and its chloride stress corrosion resistance is better than other kinds of stainless steel, which belong to this category of Crl7, Cr17Mo2Ti, Cr25, Cr25Mo3Ti, Cr28 and so on. Ferritic stainless steel because of high chromium content, corrosion resistance and oxidation resistance are relatively good, but the mechanical properties and process performance is poor, mostly used for the force is not acid resistant structure and use as oxidation resistance steel. This kind of steel can resist the corrosion of atmosphere, nitric acid and brine solution, and has the characteristics of high temperature oxidation resistance, small coefficient of thermal expansion, etc. It is used for nitric acid and food factory equipment, and can also be made to work at high temperature parts, such as gas turbine parts.

Chromium is more than 18%, but also contains about 8% nickel and a small amount of molybdenum, titanium, nitrogen and other elements. Good comprehensive performance, can withstand a variety of media corrosion. The common grades of austenitic stainless steel are 1Cr18Ni9, 0Cr19Ni9 and so on. 0 cr19ni9 steel Wc< 0.08%, marked as "0" in steel. This type of steel contains a large amount of Ni and Cr, which makes the steel appear as austenite at room temperature. This kind of steel has good plasticity and toughness, weldability and corrosion resistance and non-magnetic or weak magnetic, the corrosion resistance in oxidizing and reducing medium are good, used to make acid equipment, such as corrosion resistant containers and equipment lining, pipelines, nitric acid resistant equipment parts, etc., also can be used as the main body of watches and clocks jewelry stainless steel material. Austenitic stainless steel is generally treated with solid solution, that is, the steel is heated to 1050 ~ 1150℃, and then water or air cooled to obtain a single-phase austenitic structure.

It has the advantages of austenite and ferritic stainless steel, and has superplasticity. Stainless steel with austenitic and ferritic structures of about half each. In the case of low carbon content, chromium (Cr) content in 18%~28%, nickel (Ni) content in 3%~10%. Some steels also contain Mo, Cu, Si, Nb, Ti, N and other alloying elements. This kind of steel has the characteristics of austenite and ferritic stainless steel, compared with ferritic, higher plasticity, toughness, no room temperature brittleness, intergranular corrosion resistance and welding performance are significantly improved, but also maintain the 475℃ brittleness of ferritic stainless steel and high thermal conductivity, with superplasticity and other characteristics. Compared with austenitic stainless steel, its strength is high and its resistance to intergranular corrosion and chloride stress corrosion is obviously improved. Dual phase stainless steel has excellent corrosion resistance and is also a nickel saving stainless steel.

The matrix is austenite or martensite structure, and the common grade of precipitated hardened stainless steel is 04Cr13Ni8Mo2Al, etc. Stainless steel that can be hardened by precipitation hardening (also known as age hardening) treatment.

High strength, but poor plasticity and weldability. Martensitic stainless steel commonly used brands are 1Cr13, 3Cr13, etc., because of the higher carbon content, it has higher strength, hardness and wear resistance, but the corrosion resistance is slightly worse, for higher mechanical properties, corrosion resistance requirements of some parts, such as spring, steam turbine blades, hydraulic valve, etc. This type of steel is used after quenching and tempering. Annealing is required after forging and stamping.

Stainless steel plate and strip for pressure equipment

Special stainless steel for pressure vessels, its classification and code, size, shape and allowable deviation, technical requirements, test methods, inspection rules, packaging, marking and product quality certificate have clear requirements. Common brand number 06Cr19Ni10, 022Cr17Ni12Mo2 number code: S30408, S31603 and so on. Mainly used in food machinery, pharmaceutical machinery and other sanitary equipment.