US20140338794A1 - Method of producing grain-oriented electrical steel sheet having excellent iron loss properties - Google Patents

Method of producing grain-oriented electrical steel sheet having excellent iron loss properties Download PDF

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US20140338794A1
US20140338794A1 US14/344,805 US201214344805A US2014338794A1 US 20140338794 A1 US20140338794 A1 US 20140338794A1 US 201214344805 A US201214344805 A US 201214344805A US 2014338794 A1 US2014338794 A1 US 2014338794A1
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mass
annealing
steel sheet
primary recrystallization
heating rate
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Yukihiro Shingaki
Makoto Watanabe
Kunihiro Senda
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JFE Steel Corp
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    • 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
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • 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
    • C21D8/1261—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 following hot 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
    • C21D8/1272—Final recrystallisation annealing
    • 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
    • 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
    • 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
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • 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
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • 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
    • 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
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/16—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets
    • 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
    • C21D2201/00—Treatment for obtaining particular effects
    • C21D2201/05—Grain orientation
    • 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
    • C21D8/1222—Hot 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
    • C21D8/1216—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
    • C21D8/1266—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 between cold rolling steps

Definitions

  • This invention relates to a method of producing a grain-oriented electrical steel sheet, and more particularly to a method of producing a grain-oriented electrical steel sheet being excellent in the iron loss properties throughout the whole length of a product coil.
  • the grain-oriented electrical steel sheet is a soft magnetic material where its crystal orientation is highly oriented in the Goss orientation ( ⁇ 110 ⁇ 001>) and is mainly used as cores for transformers or the like.
  • the grain-oriented electrical steel sheet used in the transformer is required to have low iron loss W 17/50 (W/kg) representing magnetic loss when being magnetized to 1.7 T at a frequency of 50 Hz in order to reduce no-load loss (energy loss).
  • the iron loss of the electrical steel sheet is represented as the sum of hysteresis loss depending on crystal orientation, purity and the like and eddy-current loss depending on specific resistance, sheet thickness, magnetic domain size and the like. Therefore, as a method for reducing the iron loss are known a method of enhancing an accumulation degree of crystal orientation to improve a magnetic flux density, a method of increasing Si content for enhancing an electric resistance, a method of reducing a thickness of a steel sheet, a method of refining secondary recrystallized grains, a method of refining magnetic domain and so on.
  • Patent Document 1 discloses that the grain-oriented electrical steel sheet having extremely low iron loss can be obtained by heating the steel sheet rolled to a final thickness to a temperature of not lower than 700° C.
  • Patent Document 2 discloses that the grain-oriented electrical steel sheet having extremely low iron loss can be obtained by rapidly heating the steel sheet rolled to a final thickness to 800 ⁇ 950° C. at a heating rate of not less than 100° C./sec in an atmosphere having an oxygen concentration of not more than 500 ppm before the decarburization annealing, and conducting decarburization annealing wherein a temperature of a preceding zone at the decarburization annealing step is 775 ⁇ 840° C.
  • Patent Documents 3 and 4 disclose that grain-oriented electrical steel sheets being excellent in the film properties and magnetic properties can be obtained by heating a temperature zone of at least not less than 600° C. at a heating stage of decarburization annealing step to not lower than 800° C. at a heating rate of not less than 95° C./s or not less than 100° C./s and properly controlling an atmosphere of this temperature zone.
  • Patent Document 1 JP-A-H07-062436
  • Patent Document 2 JP-A-H10-298653
  • Patent Document 3 JP-A-2003-027194
  • Patent Document 4 JP-A-2000-204450
  • the invention is made in view of the above problems inherent to the conventional techniques and is to propose a method of producing a grain-oriented electrical steel sheet which is capable of stabilizing secondary recrystallization behavior to refine secondary recrystallized grains over a full length of a product coil to thereby make the iron loss of the full length of the product coil lower.
  • low temperature zone a relatively low temperature zone mainly enhancing only the recovery
  • high temperature zone a relatively high temperature zone enhancing both of the recovery and the recrystallization
  • the invention includes a method of producing a grain-oriented electrical steel sheet which comprises a series of steps of hot rolling a steel slab having a chemical composition of C: 0.001 ⁇ 0.10 mass %, Si: 1.0 ⁇ 5.0 mass %, Mn:0.01 ⁇ 0.5 mass %, sol.
  • T1 (° C.): 500+2 ⁇ (NB ⁇ NA) (1);
  • an average heating rate S2 from the temperature T2 to 750° C. is set to 0.1 ⁇ 0.7 times of S1, wherein NA represents N amount (massppm) precipitated after the final cold rolling and NB represents N amount (massppm) precipitated after the primary recrystallization annealing in the equations (1) and (2).
  • the method of producing a grain-oriented electrical steel sheet according to an embodiment of the invention is characterized in that a total N content in the steel slab NB′(massppm) is used instead of the N amount precipitated after the primary recrystallization annealing NB (massppm).
  • the method of producing a grain-oriented electrical steel sheet according to an embodiment of the invention is characterized in that the steel slab contains one or more selected from Cu: 0.01 ⁇ 0.2 mass %, Ni: 0.01 ⁇ 0.5 mass %, Cr: 0.01 ⁇ 0.5 mass %, Mo: 0.01 ⁇ 0.5 mass %, Sb: 0.01 ⁇ 0.1 mass %, Sn: 0.01 ⁇ 0.5 mass %, Bi: 0.001 ⁇ 0.1 mass %, P: 0.001 ⁇ 0.05 mass %, Ti: 0.005 ⁇ 0.02 mass % and Nb: 0.0005 ⁇ 0.100 mass % in addition to the above chemical composition.
  • the secondary recrystallized grains can be stably refined over the full length of the product coil, so that it is possible to produce a grain-oriented electrical steel sheet having low iron loss in a high yield.
  • FIG. 1 is a view illustrating a comparison between heating pattern of an embodiment of the invention and heating pattern of the conventional technique in primary recrystallization annealing.
  • the refining of the secondary recrystallized grains can be stably attained by setting a high heating rate with respect to a relatively low temperature zone mainly enhancing only the recovery (low temperature zone) and setting a heating rate lower than that of the low temperature zone with respect to a relatively high temperature zone enhancing both of the recovery and the recrystallization (high temperature zone).
  • a nucleus of the Goss orientation ( ⁇ 110 ⁇ 001>) is located in a deformation band formed in ⁇ 111 ⁇ fiber structure easily storing strain energy of rolling structure.
  • the deformation band is a region particularly storing strain energy in the ⁇ 111 ⁇ fiber structure.
  • the heating rate of the low temperature zone in the primary recrystallization annealing is low, a deformation band having extremely high strain energy is preferentially recovered to release the strain energy, so that the recrystallization of the Goss orientation nucleus is hardly caused. While when the heating rate of the low temperature zone is high, the deformation band can be kept at a state of the high strain energy to a high temperature, so that the recrystallization of the Goss orientation nucleus can be preferentially caused.
  • the ⁇ 111 ⁇ primary recrystallization texture is produced by the recrystallization of the ⁇ 111 ⁇ fiber structure in the rolling texture. Also, since the rolling texture is oriented in the ⁇ 111 ⁇ fiber structure, the main orientation of the primary recrystallization texture is the ⁇ 111 ⁇ primary recrystallization texture unless any special heat treatment is conducted. Also, the ⁇ 111 ⁇ fiber structure is high in the strain energy as compared to other surrounding textures though the energy is not so much as that of the deformation band generating nuclei of the Goss orientation. Therefore, it is said to be a crystal orientation easy to be recrystallized next to the Goss orientation under a heat treatment condition that the rapid-heating is conducted in the low temperature zone mainly enhancing only the recovery.
  • the ranges of the low temperature zone and the high temperature zone have a close relation to the recovery temperature and recrystallization temperature of the material, so that they vary depending on the precipitation state of solute nitrogen having an effect of inhibiting polygonization of dislocation in the primary recrystallization annealing to delay the recovery of the structure and the start of the recrystallization, concretely by N amount precipitated in the primary recrystallization annealing. Therefore, it is necessary to change the heating rate depending on the above precipitated N amount.
  • the invention is based on the technical idea described above.
  • the C is an element useful for generating the Goss orientation grains and is necessary to be included in an amount of not less than 0.001 mass % in order to develop such an effect.
  • the C amount exceeds 0.10 mass %, there is a risk of deteriorating the magnetic properties due to an insufficient decarburization in the decarburization annealing. Therefore, the C amount is in the range of 0.001 to 0.10 mass %. Preferably, it is in the range of 0.005 to 0.08 mass %.
  • Si has an effect of increasing an electrical resistance of steel to reduce iron loss and is preferably added in an amount of at least 1.0 mass % in the invention.
  • the Si amount is in the range of 1.0 to 5.0 mass %. More preferably, it is in the range of 2.0 to 4.5 mass %.
  • Mn not only effectively contributes to the improvement of the hot brittleness of steel, but also forms precipitates of MnS, MnSe or the like to develop a function as an inhibitor when S and Se are included.
  • the Mn content is less than 0.01 mass %, the above effect is not sufficient, while when the addition amount exceeds 0.5 mass %, the slab heating temperature required for dissolving the precipitates such as MnS, MnSe or the like becomes extremely high, which is not preferable. Therefore, the Mn content is in the range of 0.01 to 0.5 mass %. Preferably, it is in the range of 0.01 to 0.3 mass %.
  • Al is a useful element forming AlN in steel and precipitating as a second dispersion phase to act as an inhibitor.
  • the content as sol. Al is less than 0.003 mass %, the sufficient precipitation amount cannot be ensured and the above effect is not obtained.
  • it exceeds 0.050 mass % as sol. Al the slab heating temperature necessary for solid solution of AlN becomes extremely high and also AlN is coarsened by the heat treatments after the hot rolling to lose the function as an inhibitor. Therefore, Al content is in the range of 0.003 to 0.050 mass % as sol. Al. Preferably, it is in the range of 0.005 to 0.040 mass %.
  • N is an element required for forming AlN as an inhibitor like Al.
  • the addition amount is less than 0.0010 mass %, the precipitation of AlN is insufficient, while when it exceeds 0.020 mass %, blistering or the like is caused in heating the slab. Therefore, N content is in the range of 0.0010 to 0.020 mass %. Preferably, it is in the range of 0.0030 to 0.015 mass %.
  • S and Se are useful elements which are precipitated as a second dispersion phase in steel by bonding to Mn or Cu to form MnS, MnSe, Cu 2-x S or Cu 2-x Se to thereby act as an inhibitor.
  • the addition amount of S and Se in total is less than 0.005 mass %, the above addition effect is not obtained sufficiently, while when it exceeds 0.040 mass %, not only solving S and Se to steel is insufficient in the heating of the slab, but also surface defects are caused in a product. Therefore, the addition amount of S and Se is in the range of 0.005 to 0.040 mass % without regard for the single addition and the composite addition. Preferably, it is in the range of 0.005 to 0.0030 mass %.
  • the grain-oriented electrical steel sheet of the invention may contain at least one selected from Cu: 0.01 ⁇ 0.2 mass %, Ni: 0.01 ⁇ 0.5 mass %, Cr: 0.01 ⁇ 0.5 mass %, Mo: 0.01 ⁇ 0.5 mass %, Sb: 0.01 ⁇ 0.1 mass %, Sn: 0.01 ⁇ 0.5 mass %, Bi: 0.001 ⁇ 0.1 mass %, P: 0.001 ⁇ 0.05 mass %, Ti: 0.005 ⁇ 0.02 mass % and Nb: 0.0005 ⁇ 0.0100 mass %.
  • Cu, Ni, Cr, Mo, Sb, Sn, Bi, P, Ti and Nb are elements easily segregating into crystal grain boundary or surface or elements forming carbonitride and have a subsidiary action as an inhibitor. Therefore, the addition of these elements can further improve the magnetic properties.
  • the addition amount is less than the above lower limit, the effect of suppressing the coarsening of the primary recrystallized grains is not obtained sufficiently at a higher temperature zone of the secondary recrystallization process, while when it exceeds the above upper limit, there is a risk of causing poor secondary recrystallization or poor appearance of the coating. Therefore, if such elements are added, it is preferable to be added in the aforementioned range.
  • the steel slab used as a raw material of the grain-oriented electrical steel sheet according to the invention preferably contains N in an amount of not less than 0.0010 mass % and a nitride-forming element such as Al or the like precipitating by forming nitride.
  • the remainder other than the aforementioned components is Fe and inevitable impurities.
  • other components may be contained within the scope not damaging the effect of the invention.
  • the method of producing the grain-oriented electrical steel sheet according to embodiments of the invention comprises a series of steps of hot-rolling a steel slab having the above chemical composition suitable for the invention, subjecting the hot rolled sheet to a hot band annealing if necessary, subjecting the sheet to a single cold rolling or two or more cold rollings with an intermediate annealing therebetween to obtain a cold rolled sheet having a final thickness, subjecting the cold rolled sheet to primary recrystallization annealing, applying an annealing separator composed mainly of MgO, Al 2 O 3 or the like, and subjecting the sheet to a final annealing.
  • the method of producing the steel slab is not particularly limited except that it is preferable to adjust the chemical composition so as to conform with the invention, and well-known production methods can be used. Also, the reheating temperature of the steel slab prior to the hot rolling is preferable to be not lower than 1300° C. because it is necessary to solve the inhibitor-forming elements completely.
  • the conditions of the hot rolling, the conditions of the hot band annealing conducted if necessary, and the conditions of the single cold rolling or two or more cold rollings with an intermediate annealing therebetween for the formation of a cold rolled sheet having a final thickness are not particularly limited as long as they are conducted according to the usual manner. Moreover, aging between rolling passes or warm rolling may be properly adopted in the cold rolling. The production conditions after the cold rolling will be explained below.
  • the effect of stably reducing the iron loss can be obtained by setting the heating rate in the low temperature zone to not less than 80° C./sec which is higher than of the usual primary recrystallization annealing and setting the heating rate in the high temperature zone to the range of 0.1 to 0.7 times of the heating rate of the low temperature zone.
  • the temperature ranges of the low temperature zone and high temperature zone during the heating process are determined based on the precipitation state of N in the steel sheet.
  • the solute nitrogen existing after the cold rolling is unevenly distributed on the crystal grain boundary or dislocation and forms nitrides to be finely precipitated on the dislocation during the heating process of the primary recrystallization annealing so that it has an effect of limiting the movement of the dislocation to inhibit the polygonization, or an effect of recovering the rolled structure or delaying the recrystallization. Therefore, it is considered that the amount of N precipitated in the primary recrystallization annealing largely affects the recovery or the recrystallization.
  • the inventors have measured N amount NA (massppm) precipitated in the steel sheet after the final cold rolling and N amount NB (massppm) precipitated in the steel sheet after the primary recrystallization annealing and presumed the difference (NB ⁇ NA) (massppm) to be N amount newly precipitated by the primary recrystallization annealing and made many experiments for studying a relation between the difference (NB ⁇ NA) and heating conditions for obtaining good magnetic properties (heating rate, temperature range). As a result, we have found that proper heating conditions exist depending on (NB ⁇ NA) as mentioned later.
  • a heating rate S1 between a temperature T1 determined from the following equation (1) and a temperature T2 determined from the following equation (2) is necessary to be not less than 80° C./sec.
  • the heating rate Si in this temperature range is slower than 80° C./sec, the recovery is caused in the deformation band producing the nucleus of the Goss orientation ⁇ 110 ⁇ ⁇ 001>, and preferential recrystallization in the nucleus of the Goss orientation is not caused and the number of the nuclei of the Goss orientation cannot be increased, so that secondary recrystallized grains cannot be refined.
  • the heating rate in the low temperature zone is sufficient to be not less than 80° C./sec, so that an average heating rate from a temperature lower than T1 may be not less than 80° C./sec.
  • the lowest temperature of the temperature range in the high temperature zone is the highest temperature T2 in the low temperature zone and corresponds to the temperature starting recrystallization of only a specific crystal orientation (Goss orientation) when heated at the heating rate S1.
  • the highest temperature is a temperature of 750° C. recrystallizing almost all crystals.
  • the reason why the heating rate S2 is related to S1 is considered due to the fact that as the heating rate in the low temperature zone becomes higher, the recovery of the Goss orientation being preferentially recrystallized can be at an inhibited state, and even if a retention time in the high temperature zone is made short, the recrystallization of the Goss orientation can be promoted and an optimum heating rate in the high temperature zone becomes high in accordance with the heating rate S1 in the low temperature zone.
  • the heating rate S2 in the high temperature zone is too high, the recrystallization of texture intended to preferentially recrystallize is also at an inhibited state, and all of orientations is recrystallized to randomize recrystallization texture to thereby cause poor secondary recrystallization. Therefore, it is preferable to limit the heating rate S2 to not more than 0.7 times of S1. Inversely, when the heating rate S2 is too slow, ⁇ 111 ⁇ primary recrystallized texture is increased and the effect of refining secondary grains is not obtained, so that it is preferable to be not less than 0.1 times of S1.
  • the preferable S2 is in the range of 0.2 to 0.6 times of S1.
  • the primary recrystallization annealing is ordinarily conducted in combination with decarburization annealing. Even in the invention, the primary recrystallization annealing combined with decarburization annealing may be conducted. In this case, it is preferable that the decarburization annealing is conducted by heating at a heating rate suitable for the invention under such a wet hydrogen atmosphere that an oxidation potential PH 2 O/PH 2 of the atmosphere is not less than 0.1. Furthermore, when there is restriction on the annealing facility, the decarburization annealing may be performed after the heating treatment at the temperature range and heating rate suitable for the invention is conducted in a non-oxidizing atmosphere.
  • the steel sheet subjected to the primary recrystallization annealing as described above is subsequently coated on the steel sheet surface with an annealing separator and then subjected to a final annealing of generating secondary recrystallization.
  • the annealing separator can be used, for example, ones composed mainly of MgO and added with TiO 2 if necessary, in case of forming forsterite coating or ones composed mainly of SiO 2 or Al 2 O 3 in case of forming no forsterite coating.
  • a product sheet is obtained by applying and baking an insulation coating on the surface of the steel sheet or subjecting to flattening annealing for correcting the shape if necessary.
  • the kind of the insulation coating is not particularly limited, but it is preferable to use a tension coating for providing tensile force to the surface of the steel sheet in order to further reduce the iron loss.
  • the insulation coating may be formed by again applying an aqueous slurry composed mainly of MgO onto the surface of the steel sheet after the final annealing and subjecting to an annealing for forming a forsterite coating.
  • the steel sheet after the final annealing may be subjected to a well-known magnetic domain subdividing treatment by lineally conducting plasma jet or laser irradiation or electron beam irradiation or by providing linear strain with a protruded roll.
  • the secondary recrystallization texture can be stably refined over the full length of the product coil, so that grain-oriented electrical steel sheets having low iron loss can be produced in a high yield.
  • a steel slab containing C: 0.06 mass %, Si: 3.3 mass %, Mn: 0.08 mass %, S: 0.023 mass %, sol. Al: 0.03 mass %, N: 0.008 mass %, Cu: 0.2 mass % and Sb: 0.02 mass % is heated to 1430° C. and soaked for 30 minutes and hot rolled to obtain a hot rolled sheet having a sheet thickness of 2.2 mm, which is subjected to a hot band annealing at 1000° C. for 1 minute, cold rolled to obtain an intermediate cold rolled sheet having a sheet thickness of 1.5 mm and subjected to an intermediate annealing.
  • the intermediate annealing is conducted under two conditions that the sheet is heated to 1100° C.
  • the sheet is further cold rolled to obtain a cold rolled sheet having a final thickness of 0.23 mm.
  • a test specimen of 100 mm ⁇ 300 mm is taken out from a central portion in longitudinal and widthwise directions of each of the cold rolled sheet coils thus obtained and subjected to a primary recrystallization annealing combined with a primary recrystallization and decarburization in a laboratory.
  • the primary recrystallization annealing is conducted with an electrical heating furnace by heating while varying heating rates from 300° C. and 800° C. as shown in Table 1 and then promoting decarburization while keeping at 840° C. for 2 minutes. In this case, PH 2 O/PH 2 of the atmosphere is controlled to 0.3.
  • test specimen taken out from the cold rolled sheet is electrolyzed, filtered and extracted with an AA-based electrolytic solution (acetylacetone) of 10 mass %, and then N amount precipitated in the cold rolled sheet is quantified from the remaining residue to determine N amount precipitated in the cold rolled sheet NA.
  • N amount precipitated in the steel sheet after the primary recrystallization annealing is measured in the same way to determine N amount precipitated after the primary recrystallization annealing NB.
  • the difference between NA and NB (NB ⁇ NA) is determined as N amount newly precipitated by the primary recrystallization annealing.
  • test specimens subjected to the primary recrystallization annealing are prepared with respect to each of the respective heating conditions.
  • an annealing separator composed mainly of MgO and added with 10 mass % of TiO 2 is applied onto each surface of these test specimens in form of an aqueous slurry and dried, the test specimen is subjected to a final annealing to conduct secondary recrystallization and then coated and baked with a phosphate-based insulation tension coating.
  • iron loss W 17/50 is measured with a single sheet tester to determine an average value and a standard deviation.
  • the coating is removed from the test specimen by pickling, and then a secondary recrystallized grain size in a length range of 300 mm is measured by a linear analysis to determine an average value on the 50 test specimens.
  • Table.1 As seen from these results, the steel sheets subjected to the heating in the primary recrystallization annealing under conditions according to the invention are small in the secondary recrystallized grain size and good in the iron loss properties and show reduced dispersion.
  • a steel slab having a chemical composition shown in Table 2 and Table 3 is heated at 1400° C. for 20 minutes, hot rolled to obtain a hot rolled sheet of 2.0 mm in thickness, subjected to a hot band annealing at 1000° C. for 1 minute, cold rolled to obtain an intermediate cold rolled sheet of 1.5 mm in thickness, subjected to an intermediate annealing at 1100° C. for 2 minutes, cold rolled to obtain a final cold rolled sheet having a thickness of 0.23 mm, and then subjected to a magnetic domain subdividing treatment by forming linear grooves through electrolytic etching.
  • an aqueous slurry of an annealing separator composed mainly of MgO and added with 10 mass % of TiO 2 is applied and dried on the surface of the steel sheet after the primary recrystallization, and the sheet is wound in a coil, subjected to a final annealing, and subjected to a flattening annealing for the purpose of applying and baking a phosphate-based insulation tension coating and flattening the steel sheet to thereby produce a product sheet.
  • N amount precipitated in the steel sheet after the cold rolling NA and N amount precipitated in the steel sheet after the primary recrystallization NB are determined by analyzing the test specimens cut out from longitudinal end portions and widthwise central portion of the coil.
  • the sheets of Invention Examples heated under the conditions according to the invention are good in the worst value of iron loss W 17/50 and high in the ratio of the portion having iron loss W 17/50 of not more than 0.80 w/kg (achievement ratio).
  • N in steel is not actively increased (not nitrided) in the primary recrystallization as in this example, it may be considered that all of the N amount in the steel slab is precipitated after the primary recrystallization annealing. In the actual operation, therefore, if the N amount precipitated after the cold rolling (before the primary recrystallization annealing) becomes clear, it is possible to set appropriate heating rate patterns. Also, if the production condition such as annealing pattern before the final cold rolling or the like is constant, it is possible to estimate N amount precipitated in the steel sheet after the cold rolling based on preliminary research.
  • the technique of the invention is applicable to improve textures of non-oriented electrical steel sheets or to improve textures of thin steel sheets.

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Cited By (9)

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Publication number Priority date Publication date Assignee Title
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US20150007908A1 (en) * 2011-08-18 2015-01-08 Jfe Steel Corporation Method for producing oriented electromagnetic steel sheet
US9805851B2 (en) 2011-10-20 2017-10-31 Jfe Steel Corporation Grain-oriented electrical steel sheet and method of producing the same
US10294544B2 (en) 2014-05-12 2019-05-21 Jfe Steel Corporation Method for producing grain-oriented electrical steel sheet
US10294543B2 (en) 2014-05-12 2019-05-21 Jfe Steel Corporation Method for producing grain-oriented electrical steel sheet
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US20230029310A1 (en) * 2019-12-18 2023-01-26 Posco Grain-oriented electrical steel sheet and manufacturing method therefor
EP3992324A4 (en) * 2019-08-13 2023-08-02 Baoshan Iron & Steel Co., Ltd. High-magnetic-induction oriented silicon steel and manufacturing mathod therefor

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IN2015DN02841A (enrdf_load_stackoverflow) * 2012-09-27 2015-09-11 Jfe Steel Corp
CN107109552B (zh) * 2014-10-06 2018-12-28 杰富意钢铁株式会社 低铁损取向性电磁钢板及其制造方法
JP7214974B2 (ja) * 2018-03-30 2023-01-31 日本製鉄株式会社 方向性電磁鋼板の製造方法
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KR102579761B1 (ko) 2019-01-16 2023-09-19 닛폰세이테츠 가부시키가이샤 방향성 전자 강판의 제조 방법
JP7463976B2 (ja) * 2020-02-28 2024-04-09 Ｊｆｅスチール株式会社 方向性電磁鋼板の製造方法
JP7364966B2 (ja) * 2020-06-24 2023-10-19 日本製鉄株式会社 方向性電磁鋼板の製造方法
CN111663081B (zh) * 2020-07-10 2021-07-27 武汉科技大学 一种采用低温加热板坯的含铌取向硅钢及生产方法
KR20250047800A (ko) * 2022-09-30 2025-04-04 닛폰세이테츠 가부시키가이샤 무방향성 전자 강판 및 무방향성 전자 강판의 제조 방법

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4898626A (en) * 1988-03-25 1990-02-06 Armco Advanced Materials Corporation Ultra-rapid heat treatment of grain oriented electrical steel
WO2011105054A1 (ja) * 2010-02-24 2011-09-01 Ｊｆｅスチール株式会社 方向性電磁鋼板の製造方法
US20140251514A1 (en) * 2011-10-20 2014-09-11 Jfe Steel Corporation Grain-oriented electrical steel sheet and method of producing the same (as amended)

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE789262A (fr) 1971-09-27 1973-01-15 Nippon Steel Corp Procede de formation d'un film isolant sur un feuillard d'acierau silicium oriente
JPS5652117B2 (enrdf_load_stackoverflow) 1973-11-17 1981-12-10
RU2041268C1 (ru) * 1991-10-25 1995-08-09 Армко Инк. Способ получения высококремнистой электротехнической стали
JP2983128B2 (ja) * 1993-08-24 1999-11-29 新日本製鐵株式会社 極めて低い鉄損をもつ一方向性電磁鋼板の製造方法
KR100440994B1 (ko) * 1996-10-21 2004-10-21 제이에프이 스틸 가부시키가이샤 방향성전자강판및그제조방법
DE69706388T2 (de) * 1996-10-21 2002-02-14 Kawasaki Steel Corp., Kobe Kornorientiertes elektromagnetisches Stahlblech
JP3456862B2 (ja) 1997-04-25 2003-10-14 新日本製鐵株式会社 極めて低い鉄損をもつ一方向性電磁鋼板の製造方法
DE69913624T2 (de) * 1998-09-18 2004-06-09 Jfe Steel Corp. Kornorientieres Siliziumstahlblech und Herstellungsverfahren dafür
JP3386751B2 (ja) * 1999-06-15 2003-03-17 川崎製鉄株式会社 被膜特性と磁気特性に優れた方向性けい素鋼板の製造方法
JP3873489B2 (ja) * 1998-11-10 2007-01-24 Ｊｆｅスチール株式会社 被膜特性および磁気特性に優れる方向性けい素鋼板の製造方法
JP3537339B2 (ja) 1999-01-14 2004-06-14 新日本製鐵株式会社 皮膜特性と磁気特性に優れた方向性電磁鋼板及びその製造方法
JP4598320B2 (ja) 2001-07-12 2010-12-15 新日本製鐵株式会社 方向性電磁鋼板の製造方法
WO2006132095A1 (ja) * 2005-06-10 2006-12-14 Nippon Steel Corporation 磁気特性が極めて優れた方向性電磁鋼板及びその製造方法
BRPI0712010B1 (pt) * 2006-05-24 2014-10-29 Nippon Steel & Sumitomo Metal Corp Métodos de produção de uma chapa de aço elétrico com grãos orientados
JP5300210B2 (ja) * 2006-05-24 2013-09-25 新日鐵住金株式会社 方向性電磁鋼板の製造方法
JP5760590B2 (ja) * 2011-03-30 2015-08-12 Ｊｆｅスチール株式会社 方向性電磁鋼板の製造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4898626A (en) * 1988-03-25 1990-02-06 Armco Advanced Materials Corporation Ultra-rapid heat treatment of grain oriented electrical steel
WO2011105054A1 (ja) * 2010-02-24 2011-09-01 Ｊｆｅスチール株式会社 方向性電磁鋼板の製造方法
US20130074996A1 (en) * 2010-02-24 2013-03-28 Jfe Steel Corporation Method for manufacturing grain oriented electrical steel sheet
US20140251514A1 (en) * 2011-10-20 2014-09-11 Jfe Steel Corporation Grain-oriented electrical steel sheet and method of producing the same (as amended)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140202599A1 (en) * 2011-08-12 2014-07-24 Jfe Steel Corporation Method for producing oriented magnetic steel sheet
US9640320B2 (en) * 2011-08-12 2017-05-02 Jfe Steel Corporation Method of producing grain-oriented electrical steel sheet
US20150007908A1 (en) * 2011-08-18 2015-01-08 Jfe Steel Corporation Method for producing oriented electromagnetic steel sheet
US9290824B2 (en) * 2011-08-18 2016-03-22 Jfe Steel Corporation Method of producing grain-oriented electrical steel sheet
US9805851B2 (en) 2011-10-20 2017-10-31 Jfe Steel Corporation Grain-oriented electrical steel sheet and method of producing the same
US10294543B2 (en) 2014-05-12 2019-05-21 Jfe Steel Corporation Method for producing grain-oriented electrical steel sheet
US10294544B2 (en) 2014-05-12 2019-05-21 Jfe Steel Corporation Method for producing grain-oriented electrical steel sheet
CN110832112A (zh) * 2017-07-13 2020-02-21 日本制铁株式会社 方向性电磁钢板
US11145446B2 (en) * 2017-07-13 2021-10-12 Nippon Steel Corporation Grain-oriented electrical steel sheet
CN110832112B (zh) * 2017-07-13 2021-12-21 日本制铁株式会社 方向性电磁钢板
EP3733915A4 (en) * 2017-12-26 2020-11-04 Posco ELECTRICAL ORIENTED STEEL SHEET AND ITS PRODUCTION PROCESS
US12404572B2 (en) 2017-12-26 2025-09-02 Posco Co., Ltd Oriented electrical steel sheet and method for preparing same
EP3992324A4 (en) * 2019-08-13 2023-08-02 Baoshan Iron & Steel Co., Ltd. High-magnetic-induction oriented silicon steel and manufacturing mathod therefor
US20230029310A1 (en) * 2019-12-18 2023-01-26 Posco Grain-oriented electrical steel sheet and manufacturing method therefor
US12331370B2 (en) * 2019-12-18 2025-06-17 Posco Grain-oriented electrical steel sheet and manufacturing method therefor

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