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  • C21D6/00—Heat treatment of ferrous alloys
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  • C21D3/00—Diffusion processes for extraction of non-metals; Furnaces therefor
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  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1216—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the working steps
  • C21D8/1222—Hot rolling
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  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1216—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the working steps
  • C21D8/1233—Cold rolling
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  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment
  • C21D8/1255—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment with diffusion of elements, e.g. decarburising, nitriding
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  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment
  • C21D8/1261—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment following hot rolling
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  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment
  • C21D8/1272—Final recrystallisation annealing
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  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1277—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular surface treatment
  • C21D8/1283—Application of a separating or insulating coating
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  • 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
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  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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  • C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
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  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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  • C22C38/00—Ferrous alloys, e.g. steel alloys
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  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C8/02—Pretreatment of the material to be coated
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  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
  • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
  • C23C8/24—Nitriding
  • C23C8/26—Nitriding of ferrous surfaces
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  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C8/80—After-treatment
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  • C21D2201/00—Treatment for obtaining particular effects
  • C21D2201/05—Grain orientation

Definitions

• the present invention relates to an oriented silicon steel and manufacturing method thereof, in particular to an oriented silicon steel having low magnetostriction and manufacturing method thereof.
• Oriented silicon steel is a soft magnetic material characterized by sharp ⁇ 110 ⁇ 001> orientation (i.e., Gaussian grains). Oriented silicon steel, which is an important functional material, is commonly used in the manufacture of transformer cores.
• oriented silicon steel can be divided into common oriented silicon steel (abbreviated as CGO) and high magnetic oriented silicon steel (abbreviated as Hi-B); compared with CGO silicon steel, Hi-B silicon steel has lower iron loss, higher magnetic induction intensity, and smaller magnetostriction.
• CGO common oriented silicon steel
• Hi-B silicon steel has lower iron loss, higher magnetic induction intensity, and smaller magnetostriction.
• transformer noise performance has become a key indicator for manufacturers. Since the magnetostriction of oriented silicon steel has a decisive influence on the noise performance of transformers, oriented silicon steel with low magnetostriction has become a research hotspot.
• the prior art mainly reduces the magnetostriction of the oriented silicon steel by the following three technical routes: 1) increasing the Gaussian grain orientation degree of the oriented silicon steel product; 2) decreasing the thickness of the oriented silicon steel product; and 3) applying a high tensile coating. All these three technical routes can reduce the magnetostriction of oriented silicon steel.
• CN111748731A (disclosed on Oct. 9, 2020 , "Oriented silicon steel with low magnetostriction and manufacturing method thereof") produces preferred grain orientation (magnetic domain structure rearrangement) triggered by a portion of magnetic inhomogeneity due to partly sequential structural arrangement by hot stretching and magnetic annealing of a silicon steel substrate under specific conditions, so that the unidirectional magnetic anisotropy along the rolling direction is increased (i.e., the volume of the 180° magnetic domain wall is increased, and the volume of the 90° magnetic domain wall is decreased), which reduces the volume of the 90° magnetic domains of the oriented silicon steel product, and thus reduces the magnetostriction of the oriented silicon steel, which in turn reduces the overall noise level of the transformer.
• the application performed magnetic annealing under the following conditions: a magnetic annealing temperature of 750-200°C, a magnetic field oriented in the direction of rolling or transverse, and a pulsed field (50ms, 1-10 Hz) with a magnitude of 2500 A/m DC magnetic field + 50,000 A/m short-time pulsed magnetic field.
• the resulting oriented silicon steel product has an L v A(17/50) ⁇ 55 dB(A).
• CN105220071A discloses an oriented silicon steel having 0.1% ⁇ Cu ⁇ 0.5% and 0.01% ⁇ S ⁇ 0.05% in the oriented silicon steel substrate, and the atomic ratio Cu/S satisfies: 5 ⁇ Cu/S ⁇ 10.
• the coating tension on the steel surface, and the grain size of the product are strictly controlled.
• the L v A(17) of the resulting oriented silicon steel product is less than 55 dB(A), and the vibration generated by the core of the transformer made of this oriented silicon steel is small, so that the overall noise level of the transformer is reduced.
• CN107881411A discloses a low-iron-loss and low-noise oriented silicon steel.
• the application reduces iron loss and reduces magnetostriction/reduces noise by strictly controlling the vertical reflectivity R of the magnesium silicate bottom layer of the oriented silicon steel substrate to visible light to 40-60%, while ensuring that the magnesium silicate bottom layer has a uniform brightness.
• the vibration noise of magnetostriction of the final product is less than 60 dB(A), which is particularly suitable for transformers.
• the magnetostriction can be reduced to some extent by controlling both the 90° magnetic domain distribution and the coating tension level.
• both of these methods require the use of additional external equipment or conditions to reduce the magnetostriction, and the reduction magnitude in magnetostriction is not significant.
• the reduction magnitude of the magnetostriction by the externally applied conditions at a later stage is relatively limited if the Gaussian texture of the oriented silicon steel substrate itself is not sharp enough.
• the method of refining the magnetic domains by increasing the coating tension has the same problem, and the method also has very high requirements on the coating properties.
• the magnetostriction can be reduced to some extent by reducing the thickness of the silicon steel sheet. However, due to the high silicon content of silicon steel, rolling the silicon steel to a thinner thickness would be more difficult and also result in increased costs.
• the prior art for reducing magnetostriction by increasing the coating tension and reducing the thickness of the silicon steel have significant limitations.
• by improving the Gaussian grain orientation degree of the oriented silicon steel itself e.g., by optimizing the chemical composition and adjusting the production process to improve the Gaussian grain orientation degree of the oriented silicon steel product
• i.e., by lowering the deviation angle of the Gaussian grains thereby increasing the magnetic induction intensity
• energy saving and environmental protection is also one of the focuses of the current production process. How to ensure the high quality and stable production of oriented silicon steel under the premise of reducing energy consumption will become one of the important R&D direction of oriented silicon steel.
• the present inventor expects to develop a new type of oriented silicon steel with low magnetostriction and a manufacturing method thereof, which can essentially improve the magnetic induction intensity of the oriented silicon steel and reduce the magnetostriction of the oriented silicon steel (by lowering the deviation angle of the Gaussian grains) on the basis of a green and consumption-reducing production process through the high-level design of the chemical composition of the oriented silicon steel and the rational optimization of the production process.
• This enables a high level of matching between high magnetic induction intensity and low magnetostriction of the oriented silicon steel.
• An objective of the present invention is to provide an oriented silicon steel and a manufacturing method thereof.
• the oriented silicon steel has an excellent matching of magnetic properties (especially in terms of high magnetic induction intensity and low magnetostriction), while at the same time the consumption of energy media in the production process is substantially reduced.
• the first aspect of the present invention provides an oriented silicon steel, comprising, in addition to 90% or more of Fe and inevitable impurities, the following components in percentage by mass: C: 0.020-0.080%, Si: 2.00-4.50%, Mn: 0.01-0.10%, S ⁇ 0.005%, acid soluble aluminum Als: 0.010-0.040%, N: 0.002-0.015%, Nb: 0.006-0.120%, and at least one selected from P: 0.01-0.10%, Sn: 0.01-0.30%, and Cu: 0.01-0.50%.
• the oriented silicon steel comprises the following components in percentage by mass: C: 0.020-0.080%, Si: 2.00-4.50%, Mn: 0.01-0.10%, S ⁇ 0.005%, acid soluble aluminum Als: 0.010-0.040%, N: 0.002-0.015%, Nb: 0.006-0.120%, and at least one selected from P: 0.01-0.10%, Sn: 0.01-0.30%, and Cu: 0.01-0.50%; the balance of Fe and inevitable impurities.
• the oriented silicon steel has a thickness of 0.15-0.30 mm
• the oriented silicon steel has a magnetic induction intensity of B8>1.95 T and a magnetostrictive vibration velocity sound pressure level of L v A ⁇ 50 dB(A).
• Another aspect of the present invention provides a manufacturing method for the above oriented silicon steel, comprising the following steps:
• a thickness of the slab is 180-250 mm.
• a heating temperature of the slab is 900-1150°C.
• the present application uses an post-inhibitor process that performs nitriding treatment, so that the content of inhibitor elements in the slab is relatively low.
• the heating temperature in step 2) is conducive to energy consumption reduction and obtaining sufficient inhibitor at the same time.
• the heating temperature of the slab is lower than 900°C, the inhibitor elements cannot be effectively solid-solutionized; when the heating temperature of the slab is higher than 1150°C, it will increase the energy consumption and the heat load of the heating furnace. Therefore, the heating temperature of the slab in step 2) is preferably controlled to be 900-1150°C.
• a thickness of the intermediate slab at the end of rough rolling is 35-50 mm
• an end temperature of rough rolling is higher than 950°C
• a coiling temperature is 800-1050°C
• a coiling time is 30-200s
• an initial temperature of finishing rolling is lower than 1050°C.
• the present application sets an end temperature of rough rolling to be higher than 950°C, which can ensure that a coiling temperature is 800-1050°C, a coiling time is 30-200s, and an initial temperature of subsequent finishing rolling is lower than 1050°C.
• a coiling temperature is 800-1050°C
• a coiling time is 30-200s
• an initial temperature of subsequent finishing rolling is lower than 1050°C.
• the layers of the hot-rolled plate themselves heat each other during the post-coiling and holding process, so there is no need for additional heating; in addition, the coiling between rough rolling and finishing rolling enable a more thorough recrystallization of the hot-rolled plate structure, and at the same time can precipitate part of the inhibitors dispersively.
• the desired recrystallization effect of the structure of the hot-rolled plate cannot be achieved; when the coiling temperature is higher than 1050°C or the coiling time is more than 200s, the grain organization of the intermediate slab and the precipitated inhibitors will be coarsened, which adversely affects the development of the subsequent structure and Gaussian texture. Therefore, it is preferred to set the temperature and/or time of the hot rolling process within the above range.
• a normalizing annealing treatment is carried out, and the normalizing annealing temperature does not exceed 1000°C, preferably 800-1000°C, more preferably 800-980°C, and a normalizing annealing time is 20-200s.
• the proportion of Gaussian grains with a deviation angle less than 3° in the steel plate after decarburizing annealing is significantly lower (i.e., significantly less than 10%) if the rough-rolled plate is not coiled and held, or if the normalizing annealing temperature after coiling and holding is higher than 1000°C.
• a cold rolling reduction ratio is >80%.
• a decarburizing annealing temperature is 800-900°C.
• the decarburization effect is not obvious; when the decarburizing annealing temperature is higher than 900°C, the primarily recrystallized grain is too coarse, affecting the secondary recrystallization.
• a proportion of Gaussian grains with a deviation angle less than 3° in the steel plate after decarburizing annealing is more than 10%.
• the "proportion of Gaussian grains with a deviation angle less than 3° in the steel plate after decarburizing annealing" herein refers to the ratio (in %) of the number of Gaussian grains with a deviation angle less than 3° to the total number of Gaussian grains.
• the "deviation angle” herein refers to the deviation angle of the Gaussian grain orientation.
• the deviation angle and ratio of Gaussian grains are observed and counted by a scanning electron microscope with an electron backscatter diffraction (EBSD) system.
• EBSD electron backscatter diffraction
• an amount of nitriding is 50-280 ppm.
• the present application uses a post-inhibitor process that performs nitriding treatment.
• a nitriding treatment must be performed prior to high-temperature annealing in order to form inhibitors that sufficient to inhibit growth of the primary recrystallized grain.
• the amount of nitriding is lower than 50 ppm, the amount of inhibitor formation is insufficient; when the amount of nitriding is higher than 280 ppm, it will adversely affect the formation of the magnesium silicate bottom layer during the high-temperature annealing process.
• the amount of nitriding in step 6) of the present invention is strictly controlled to 50-280 ppm.
• the annealing separator may be an annealing separator commonly used in the art, preferably MgO.
• an annealing temperature is 1100-1250°C and an annealing time is greater than 25 hours.
• the insulation coating may be formed using a coating fluid commonly used in the art, such as forming the insulation coating by applying a coating fluid comprising phosphate, colloidal silicon dioxide, and chromic anhydride; the scoring may be performed using a scoring method commonly used in the art, such as laser scoring, electrochemical scoring, tooth roller scoring, high-pressure water beam scoring, or the like.
• the oriented silicon steel and the manufacturing method thereof according to the present invention realize the following beneficial effects:
• the present inventor found that the orientation degree of the Gaussian grain nuclei in the primary recrystallization has a decisive influence on the orientation degree of the Gaussian grain and magnetic induction intensity of the product through a large number of experiments. Therefore, the present inventor optimizes the design of the relevant process parameters, so that the proportion of Gaussian grains with a deviation angle less than3° in the steel plate after decarburizing annealing is more than 10%, thereby obtaining an oriented silicon steel product with desired Gaussian grain orientation degree and magnetic induction intensity.
• the present invention obtains an oriented silicon steel with a matched high magnetic induction intensity and low magnetostriction under the premise of an environmental-friendly and consumption-reducing production process.
• the oriented silicon steel in the present invention has excellent magnetic properties (magnetic induction intensity of B8>1.95 T, magnetostrictive vibration velocity sound pressure level of L v A ⁇ 50 dB(A)), which has good economic benefits and application prospects.
• the present inventors surprisingly discovered that by designing the chemical composition of the oriented silicon steel above, an oriented silicon steel with excellent overall performance (especially high magnetic induction intensity and low magnetostriction) can be obtained.
• the design principle of each aforementioned chemical elements is as follows. In the present application, the element contents are expressed in percentage by mass unless explicitly stated otherwise.
• C The addition of an appropriate amount of C ensures that an appropriate proportion of the ⁇ phase is obtained in the hot rolling or normalizing process, which is conducive to the precipitation of fine dispersed inhibitors.
• the C content in the steel is lower than 0.020%, the proportion of ⁇ phase is low, which is unfavorable to the precipitation of the inhibitor; when the C content in the steel is higher than 0.080%, the decarburization cost is increased.
• the C content in the oriented silicon steel of the present invention is controlled to 0.020-0.080%, preferably 0.022-0.073%.
• Si is the main element to reduce iron loss.
• the Si content in steel should not be too low or too high.
• the Si content in the silicon steel is lower than 2.00%, it is difficult to obtain the desired low iron loss in the oriented silicon steel product; when the Si content in the steel is higher than 4.50%, it leads to difficulties in cold rolling and a reduction in the product yield.
• the Si content in the oriented silicon steel of the present invention is controlled to 2.00-4.50%, preferably 2.19-4.29%.
• Mn The addition of an appropriate amount of Mn can form a small amount of MnS auxiliary inhibitor in the continuous casting and hot rolling process, which can effectively improve the microstructure and rollability of the oriented silicon steel.
• the Mn content in steel must be strictly controlled. When the Mn content is less than 0.01%, it is detrimental to obtaining the desired microstructure and rollability of the silicon steel; when the Mn content is higher than 0.10%, the slab heating temperature will be significantly increased, and it is easy to form coarse MnS inhibitors. Based on these considerations, the Mn content in the oriented silicon steel of the present invention is controlled to 0.01-0.10%, preferably 0.01-0.09%.
• S can form auxiliary inhibitors such as MnS and Cu 2 S.
• the S content in steel should not be too high. When the S content in the steel is too high, it will significantly increase the slab heating temperature, which is not favorable to production. Based on these considerations, the S content in the oriented silicon steel of the present invention is controlled to S ⁇ 0.005%, preferably ⁇ 0.004%.
• Acid soluble aluminum Als is an important component in the formation of the main inhibitor AlN.
• the acid soluble aluminum Als content in steel is lower than 0.010%, it will lead to insufficient inhibitor; when the acid soluble aluminum Als content in steel is higher than 0.040%, it will lead to coarse inhibitor AlN. Therefore, the acid soluble aluminum Als content in the silicon steel needs to be strictly controlled. Based on these considerations, the acid soluble aluminum Als content in the oriented silicon steel of the present invention is controlled to 0.010-0.040%, preferably 0.012-0.039%.
• N The addition of an appropriate amount of N can properly inhibit grain growth.
• the addition of N in silicon steel can cooperate with acid soluble aluminum Als to form AlN before nitriding, thereby effectively inhibiting the growth of the primary recrystallized grains.
• the N content in the steel is lower than 0.002%, the growth of the primary recrystallized grains cannot be effectively inhibited; when the N content in the steel is higher than 0.015%, the difficulty of steelmaking will be significantly increased.
• the N content in the oriented silicon steel of the present invention is controlled to 0.002-0.015%, preferably 0.003-0.014%.
• Nb In order to reduce the slab heating temperature, the Mn and Cu contents are relatively low, but this leads to insufficient precipitation of MnS and Cu 2 S. Therefore, in order to compensate for the lack of inhibition ability of the inhibitor, an appropriate amount of Nb is added into the silicon steel. Nb can form auxiliary inhibitor Nb (C, N), and play the role of auxiliary inhibitor. In addition, due to the relatively low solid solution temperature of Nb (C, N), it can also reduce the heating temperature of the slab. When the Nb content in the steel is lower than 0.006%, the inhibitor Nb (C, N) formed cannot fully realize the inhibitory effect; when the Nb content in the steel is higher than 0.120%, the occurrence of secondary recrystallization is hindered as the inhibitory effect is too strong. Based on these considerations, the Nb content in the oriented silicon steel of the present invention is controlled to 0.006-0.120%, preferably 0.006-0.118%.
• P and Sn are both grain boundary segregation elements.
• the addition of an appropriate amount of P and Sn in silicon steel can act as auxiliary inhibitor.
• the auxiliary inhibitor effect cannot be fully realized; when the P and Sn contents in the steel are higher than 0.10% and 0.30%, respectively, the decarburization and nitriding will be adversely affected.
• the P content in the oriented silicon steel of the present invention is controlled to 0.01-0.10%, preferably 0.02-0.08%, and the Sn content is controlled to 0.01-0.30%, preferably 0.02-0.25%.
• Cu The addition of an appropriate amount of Cu in silicon steel can not only form auxiliary inhibitors such as Cu 2 S, but also effectively expand the ⁇ -phase region, thus facilitating the precipitation of other inhibitors.
• the Cu content in steel should not be too low or too high.
• the Cu content in the silicon steel is lower than 0.01%, the above effect cannot be fully realized; when the Cu content in the silicon steel is higher than 0.50%, the production cost will be increased.
• the Cu content in the oriented silicon steel of the present invention is controlled to 0.01-0.50%, preferably 0.02-0.48%, for example 0.02-0.39%.
• the oriented silicon steel of Examples 1-12 of the present invention is manufactured by the following steps:
• Example 10 and Example 11 were also subjected to a normalizing annealing treatment (normalizing annealing temperature was not more than 1000°C, normalizing annealing time was 20-200s) between steps 3) and 4).
• Comparative Examples 1-20 used similar process steps to manufacture the oriented silicon steel, wherein the Comparative Examples other than Comparative Example 16 were also subjected to a normalizing annealing treatment between steps 3) and 4).
• the chemical composition and the process parameters of the oriented silicon steel of Examples 1-12 satisfy the claimed scope of the present invention, whereas at least one of the chemical composition and/or the process parameters of Comparative Examples 1-20 does not satisfy the claimed scope of the present invention.
• Example 1 The chemical compositions of the oriented silicon steels of Examples 1-12 and Comparative Examples 1-20 are shown in Table 1.
• Table 1 (wt%, the balance is Fe and inevitable impurities) Number C Si Mn S Als N Nb P Sn Cu
• Example 1 0.031 3.25 0.02 0.004 0.029 0.003 0.009 0.04 0.08 0.02
• Example 2 0.052 3.51 0.04 0.004 0.027 0.006 0.011 0.08 0.15 -
• Example 3 0.073 3.81 0.06 0.004 0.021 0.008 0.033 - - 0.15
• Example 4 0.066 3.03 0.08 0.004 0.018 0.011 0.062 0.06 - -
• Example 5 0.048 2.84 0.09 0.004 0.033 0.013 0.097 - 0.20 -
• Example 6 0.022 2.19 0.01 0.004 0.036 0.014 0.118 - 0.25 0.18
• Example 7 0.045 4.29 0.05 0.004 0.012 0.009
• step 5 the steel plates after decarburizing annealing of Examples 1-12 and Comparative Examples 1-20 were sampled, then the proportion of Gaussian grains with a deviation angle less than 3° of each sample was observed and analyzed by a scanning electron microscope with an electron backscatter diffraction (EBSD) system.
• EBSD electron backscatter diffraction
• the proportion of Gaussian grains with a deviation angle less than 3° in the steel plate after decarburizing annealing of Examples 1-12 is 11%-22%.
• the proportion of Gaussian grains with a deviation angle less than 3° in the steel plate after decarburizing and annealing of Comparative Examples 1-20 is 3.6%-9.4%, which is significantly lower than those of Examples 1-12.
• the oriented silicon steel products manufactured in Examples 1-12 and Comparative Examples 1-20 were sampled, and the magnetic properties of each sample were measured and analyzed to obtain the magnetic induction intensity B8 and the magnetostrictive vibration velocity sound pressure level L v A of each oriented silicon steel sample.
• Magnetic property test the magnetic induction intensity of the oriented silicon steel of Examples 1-12 and Comparative Examples 1-20 is determined in accordance with the national standard GB/T 13789-2008 "Method for Measuring the Magnetic Properties of Electrical Steel Sheets (Strips) with a Monolithic Tester".
• L v A is the magnetostrictive vibration velocity sound pressure level of oriented silicon steel under the test conditions described above.
• the unit is dB(A)
• the magnetic induction intensity B8 of Examples 1-12 is 1.954-1.972 T, and the magnetostrictive vibration velocity sound pressure level L v A is 43-48 dB(A).
• the magnetic induction intensity B8 of Comparative Examples 1-20 is 1.805-1.939 T (apparently lower than Examples 1-12), and the magnetostrictive vibration velocity sound pressure level L v A is 51-64 dB(A) (apparently higher than Examples 1-12).
• the present inventors After analyzing the proportion of Gaussian grains with a deviation angle less than 3° in the steel plate after decarburizing annealing, the present inventors surprisingly found that different combinations of hot rolling and normalizing annealing process parameters have a key influence on the deviation angle ⁇ of the Gaussian grain orientation in the steel plate after decarburizing annealing.
• the proportion of Gaussian grains with a deviation angle less than 3° in the steel plate after decarburizing annealing can be significantly increased, especially within the range of the chemical composition claimed in the present invention, by coiling and holding the rough-rolled plate at a temperature of 800-1050°C while subsequent low-temperature normalizing annealing (normalizing annealing temperatures of no more than 1000°C) is performed, or even no normalizing annealing treatment is performed.
• the present inventors have found through extensive experiments that the orientation degree of the Gaussian grain nuclei in the primary recrystallization has a decisive influence on the Gaussian grain orientation degree and the magnetic induction intensity of the product.
• the oriented silicon steel manufactured according to the method of the present invention shows a high level of matching between high magnetic induction intensity and low magnetostriction.

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• 2022
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