On 2018-08-08 14:48:54
On 2018-08-08 14:47:24
On 2018-08-08 11:45:46
With the development of society, science and technology have been developed by leaps and bounds, but followed by a series of environmental problems and ecological harmony. Carbon dioxide emissions have a negative impact on the current development of thermal power plants. The research shows that increasing steam pressure and temperature is an effective way to solve the above problems. The main high-temperature components used in thermal power plants are basically heat-resistant steel, so the development of new heat-resistant steel, improve the use temperature range of heat-resistant steel, and enhance its creep fracture strength at higher temperatures has been a hot research field in the field of metallurgy, electricity and materials.
Continuous casting of heat-resistant steel can not only improve the yield of molten steel, but also save the process of opening and returning, greatly reduce the energy consumption and significantly improve the production efficiency. The continuous casting has uniform structure, small segregation and low labor intensity. Therefore, continuous casting is not only an important measure to improve the quality and reduce the cost of heat-resistant steel production, but also an important symbol of modern production. Steel continuous casting steel cc ratio generally have higher requirements on technology and equipment, such as, heat resistant steel continuous casting temperature and chemical composition of molten steel is very strict, and requires pouring temperature control in the narrow range, in order to prevent secondary oxidation, in the process of continuous casting production requirements take no oxidation protective casting, heat resistant steel continuous casting of the ladle, tundish, slide gate, into the shuikou with refractory has strict requirements, in order to improve casting solidification organization, reduce the inclusion, center segregation, shrinkage cavity, inner crack defects, such as access to quality of continuous casting, Generally, electromagnetic stirring technology is adopted, and the cooling process of heat resisting steel continuous casting is different from that of general steel, especially martensitic steel. The casting must be put into the annealing furnace at more than 300℃ for slow cooling, so as to prevent the transformation of Martensitic steel and generate deformation cracks. The quality requirements of heat resisting steel continuous casting are much stricter than that of general steel.
High temperature resistant castings are classified according to the main use of steel
Industrial furnace with the heat resistant steel: besides furnace reactor, power plant boiler, petrochemical industry, the metallurgy, machinery, building materials, light industry and other industries, are widely used as heat exchanger, heating furnace tube, reflect the tank furnaces in various heat-resistant parts, in addition to use the heat resistant steel such as plates, tubes, rods deformation of material, and USES a lot of heat resistant steel castings.
310 (0Cr25Ni20) or 3Cr24Ni7SiNRe, 2Cr25Ni13 steel are mostly used for annealing furnace covers, muff tank, radiation tube, charging frame and chain belt of continuous heating furnace with controlled atmosphere.
High alloy heat-resistant centrifugal cast tubes are also used in a large number of bottom rollers and radiation tubes in continuous heating and heat treatment furnaces in metallurgical plants. The commonly used brands are 0Cr18Ni9, 00Cr18Ni9, 1Cr18Ni9Ti, 0Cr17Ni12Mo2, 00Cr17Ni12Mo2, 3Cr24Ni7SiNRe, 0Cr23Ni13, 1Cr20Ni14, Cr25Ni20Si2, 00Cr10Ni20Mo6Cu6, 4Cr25Ni35NbW, 70CrMoVBRe, 4Cr28Ni48W5Si2, 3Cr26Ni4MnMoRe and so on.
In the cement industry, a large number of heat-resistant steel pieces, such as 3Cr24Ni7SiNRe, 1Cr20Ni14, Cr25Ni20Si2, are used in the heat-resistant steel chains in the pre-tropical zone of wet cement kilns, grate plates for cooling machines in large cement kilns, and material buckets for cooling machines.