Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
  • C21D8/1233—Cold rolling
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
  • C21D8/1255—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest with diffusion of elements, e.g. decarburising, nitriding
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium

Definitions

• the present invention relates to the field of ferrous metallurgy and can be used in the production of cold rolled anisotropic electrical steel.
• the closest to the claimed technical solution for the combination of essential features is "The method of obtaining a sheet of electrical steel with an oriented grain structure and high magnetic properties" according to the patent of the Russian Federation jN ° 2193603. Including continuous casting of steel, obtaining a slab of steel, high temperature annealing, hot rolling , cold rolling in one or more stages, continuous primary recrystallization decarburization annealing and nitriding annealing, applying separating anti-stick coatings; and secondary recrystallization annealing in a cage oven.
• the technical result of obtaining steel with high magnetic induction is achieved by that. that continuous casting is subjected to steel containing, in mass. % from 2.5 to 4.5 silicon, from 0.015 to 0.075. preferably from 0.025 to 0.050 carbon, from 0.03 to 0.40. preferably 0.05 to 0.20 manganese, less than 0.012. preferably from 0.005 to 0.007 sulfur, from 0.010 to 0.040. preferably 0.02 to 0.035 soluble aluminum, from 0.003 to 0.013. preferably from 0.006 to 0.010 nitrogen, less than 0.005, preferably less than 0.003 titanium, iron and the remainder of the minimum amount of unavoidable impurities.
• high-temperature annealing of slabs is carried out at a temperature of from 1200 to 1320 0 C. preferably from 1270 to 1310 0 C, after hot rolling the sheet is cooled to a temperature of less than 700 0 C, preferably below 600 0 C. quick heating of the hot-rolled sheet first to a temperature of from 1000 to 1 150 0 C, preferably from 1060 to 1 130 0 C, followed by cooling, holding at a temperature of from 800 to 950 0 C.
• Secondary recrystallization annealing at the final stage of processing is performed at a temperature of from 700 to 1200 0 C for a period of time from 2 to 10 hours, preferably less than 4 hours.
• steel must have high magnetic permeability and, accordingly, high magnetic induction and at the same time minimal loss of permutation.
• the finished steel must have certain structural parameters — a perfect texture ⁇ 1 10 ⁇ ⁇ 001> and an optimal grain size, which are formed during secondary recrystallization during high-temperature annealing. Disclosure of invention
• the task to which the proposed technical solution is directed. consists in improving the magnetic properties of anisotropic electrical steel. producing anisotropic steel with low magnetization reversal losses (P
• the method for the production of anisotropic electrical steel involves the smelting of steel containing mass. % from 2.5 to 3.6 silicon, from 0.05 to 0.40 manganese, from 0.02 to 0.065 carbon, from 0.004 to 0.013 nitrogen, less than 0.012 sulfur, less than 0.005 titanium, from 0.020 to 0.035 acid-soluble aluminum, continuous casting into slabs, heating slabs in heating furnaces , hot rolling, annealing of hot rolled strips, cold rolling in one or several stages with aging operations between passes, continuous annealing of cold rolled strips during which recrystallization, decarburization in a humid nitrogen-hydrogen atmosphere and nitriding are performed. application of a heat-resistant release coating and high-temperature annealing for secondary recrystallization.
• the steel is continuously poured onto the thickness of the finished slab 220-270 mm.
• the slabs are placed in a methodical furnace at a surface temperature of slabs of at least 450 0 C. they are heated before hot rolling to a temperature of 1,100-1,200 0 C.
• the atmosphere for nitriding is obtained by passing nitrogen-hydrogen gas through an aqueous solution of ammonia NHj with a concentration of 6-25% in the solution or by mixing gaseous ammonia NH3 with the nitrogen-hydrogen atmosphere of the furnace.
• the strip is cooled after continuous annealing in an atmosphere with a hydrogen content of 50-100%.
• the invention is illustrated by the following:
• the main second phase is aluminum nitride.
• One of the main tasks of hot rolling is to isolate a certain amount of the dispersed phase necessary to prevent uncontrolled grain growth at the stages of decarburization and nitriding during continuous annealing.
• the temperature of the heating of the slab should be 1250-1300 0 C.
• the thickness of the slab from 220 to 270 mm provides the optimum cooling rate during casting, which prevents the formation of coarse inclusions of aluminum nitriles, and also due to the low thermal conductivity of silicon steel, at a surface temperature of at least 450 0 C allows you to keep the temperature from 700 0 in the central layers of the slab C and, accordingly, keep a sufficient number of phase-forming elements in the solution. Under such initial conditions, the heating of slabs before hot rolling to a temperature of 1 100 - 1200 0 C. i.e. in the interval. corresponding to the maximum amount of the ⁇ -phase in the volume of the metal, allows you to transfer and save in the solution a sufficient number of phase-forming elements.
• heating slabs before hot rolling to a temperature of 1 100 - 1200 0 C allows to reduce scale formation during heating of slabs in a heating furnace, to reduce the time it takes to stop the heating furnace to clean the scale, and to increase the productivity of the hot rolling mill.
• the initial stage of annealing - heating the strip has a great influence on the structure characteristics of the treated metal.
• the heating of the strip during continuous annealing at a rate of from 20 to 50 ° C / s to a temperature of from 750 to 800 ° C prevents the coagulation and dissolution of the complex of fine particles of the second phase, the presence of which is necessary in the deformed matrix at the initial stage of primary recrystallization.
• Particles of the dispersed phase inhibit grain growth with an orientation different from the Goss texture ⁇ 1 10 ⁇ ⁇ 001>. and contribute to the formation of microregions with an orientation close to ⁇ 1 10 ⁇ ⁇ 001>. which, transforming, ultimately provide grain growth with the indicated orientation during secondary recrystallization.
• the inhibitory phase helps to reduce the heterogeneity in the microstructure and thereby contributes to the controlled growth of primary recrystallization grains.
• Maintaining the oxidizing potential of a moist nitrogen-hydrogen atmosphere characterized by the magnitude of RnURzo. in the range from 1.9 to 2.5, not only provides a high rate of carbon removal reaction and its low final content, but also leads to the formation of an internal oxidation zone on the surface of the strip, which contains, in addition to silicon oxide, a sufficient amount of fayalite (2FeO * SiCb).
• the resulting composition of the internal oxidation zone transforming further during the soaking operations after decarburization, nitriding, and soaking after nitriding, at the declared values of the oxidation potential and during cooling to a temperature of 600-100 0 C in a dry nitrogen-hydrogen atmosphere with a hydrogen content of at least 10%, provides time of subsequent technological operations surface formation of a high-quality strip.
• Carrying out nitriding at a temperature of 780-850 0 C provides the maximum nitriding rate and obtaining the required mass fraction of nitrogen in the metal with a minimum ammonia content in the furnace atmosphere and. accordingly, with its minimum consumption. Raising the nitriding temperature above 85 ° C requires an increase in nitriding time, an increase in the concentration of ammonia in the atmosphere of the furnace, and an increase in its consumption. At temperatures below 780 0 C, the processes of nitrogen diffusion into the metal slow down sharply.
• the carbon content in the central layers is significantly higher than in the surface.
• the nitrogen content in the surface layers can be several times higher than its content in the central layers.
• the heterogeneity of the distribution of carbon and nitrogen in the metal matrix negatively affects the formation of the texture in the process of secondary recrystallization and. accordingly, at the level of magnetic properties of the finished steel.
• temperatures are raised by 5-50 0 C from the decarburization temperature, to a maximum of 870 ° C. and exposure for 10-30 seconds.
• the temperature is raised by 30-200 0 C. to a maximum of 1050 0 C '. and exposure for 15-30 seconds.
• Obtaining a nitrogen-hydrogen atmosphere for nitriding containing ammonia in the framework of the proposed method is possible by mixing the nitrogen-hydrogen atmosphere with pure gaseous ammonia or passing the nitrogen-hydrogen atmosphere through an aqueous solution of ammonia with a concentration of 6-25% in the solution.
• the second way is to use an aqueous solution of ammonia

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Electromagnetism (AREA)
• Manufacturing & Machinery (AREA)
• Manufacturing Of Steel Electrode Plates (AREA)
• Soft Magnetic Materials (AREA)
• Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

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• 2009
  • 2009-08-03 RU RU2009129759/02A patent/RU2407808C1/ru active
• 2010
  • 2010-07-27 PL PL398129A patent/PL219132B1/pl unknown
  • 2010-07-27 BR BR112012001801A patent/BR112012001801A2/pt not_active Application Discontinuation
  • 2010-07-27 WO PCT/RU2010/000413 patent/WO2011016757A1/ru active Application Filing
  • 2010-07-27 CZ CZ2012-29A patent/CZ306161B6/cs unknown

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