Classification of heat-resistant steel

Classification by alloying element content
1) Low carbon steel: In the middle of such steel contains or rarely contains other alloying elements, its carbon content is generally not more than 0.2%.
2) Low-alloy heat-resistant steel: In this kind of steel contains one or several alloying elements, but the content is not high, the total amount of alloying elements contained in the general steel does not exceed 5%, the carbon content does not exceed 0.2%.
3) High-alloy heat-resistant steel: in this kind of steel, there are many alloying elements, and the alloying element content is generally more than 10%, or even up to more than 30%.
Classification according to the characteristics of steel
1) Anti-oxidation steel (or heat-resistant non-peeling steel) : This kind of steel has good oxidation resistance and high temperature corrosion resistance at high temperatures (generally 550 ~ 1200℃), and has a certain high temperature strength. It is used to manufacture all kinds of heating furnace parts and heat exchangers, manufacture heat turbine combustion, boiler cucumbers, heating furnace bottom plate and roller table and furnace tube. Oxidation resistance is the main indicator, and the components themselves do not bear a lot of pressure.
2) Heat strength steel: at high temperatures (usually 450 ~ 900 ° C) can withstand considerable additional stress and have excellent oxidation resistance and high temperature gas corrosion resistance, and usually require periodic variable stress. It is usually used as rotor and blade of steam turbine and gas turbine, superheater of boiler, bolt and spring working at high temperature, intake and exhaust valve of internal combustion engine, petroleum hydrogenation reactor, etc.
Classification by main use of steel
Heat-resistant steel for industrial furnaces: In addition to reactors, power station boilers, petrochemical industrial furnaces, in metallurgy, machinery, building materials, light industry and other industries, widely used as heat exchangers, heating furnace tubes, reflection tanks and other furnace in a variety of heat-resistant parts, in addition to the use of plates, tubes, rods and other heat-resistant steel deformation materials, and a large number of heat-resistant steel castings. Various annealing furnace covers in metallurgical plants, Muffle tanks, radiation tubes, charging frames, chain belts, etc. of controlled atmosphere continuous heating furnaces, are mostly 310 (0Cr25Ni20) or 3Cr24Ni7SiNRe, 2Cr25Ni13 steel and so on. A large number of bottom rolls and radiation tubes in continuous heating furnaces and heat treatment furnaces in metallurgical plants are also centrifugal cast tubes of high alloy heat-resistant steel. The commonly used brands are 0Cr18Ni9, 00Cr18Ni9, 1Cr18Ni9Ti, 0Cr17Ni12Mo2, 00Cr17Ni12Mo2, 3Cr24Ni7SiNRe, 0Cr23Ni13, 1Cr20Ni14, Cr25Ni20Si2, 00Cr10Ni20M o6Cu6, 4Cr25Ni35NbW, 70CrMoVBRe, 4Cr28Ni48W5Si2, 3Cr26Ni4MnMoRe, etc. In the cement industry, a large number of heat-resistant steel parts are used, such as 3Cr24Ni7SiNRe, 1Cr20Ni14, Cr25Ni20Si2, etc., in the heat-resistant steel chain in the wet cement kiln pre-heat belt, the grate plate for the large cement kiln grate cooler, and the material bucket for the cooling machine