EP2559775B1 - Verfahren zur herstellung kornorientierter elektrischer sthalbleche - Google Patents

Verfahren zur herstellung kornorientierter elektrischer sthalbleche Download PDF

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EP2559775B1
EP2559775B1 EP12006829.1A EP12006829A EP2559775B1 EP 2559775 B1 EP2559775 B1 EP 2559775B1 EP 12006829 A EP12006829 A EP 12006829A EP 2559775 B1 EP2559775 B1 EP 2559775B1
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Prior art keywords
annealing
compound
steel sheet
annealing separator
grain
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French (fr)
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EP2559775A1 (de
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Takeshi Omura
Kazumichi Sashi
Yasuyuki Hayakawa
Masaki Kawano
Shinichi Yoshikawa
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JFE Steel Corp
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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
    • C22C38/02—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
    • C21D8/1277—Modifying the physical properties 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
    • 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
    • C22C38/04—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
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • 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

Definitions

  • the present invention relates to an annealing separator which prevents sticking between grain-oriented electrical steel sheets in annealing and to an annealing method using the above annealing separator.
  • the present invention also relates to a method for manufacturing a grain-oriented electrical steel sheet using the above annealing separator.
  • types of grain-oriented electrical steel sheets there are a steel sheet having a forsterite coating (i.e. forsterite-based coating) and a steel sheet having no forsterite coating, and the present invention relates to manufacturing methods of the respective steel sheets.
  • An electrical steel sheet is a material which has been widely used as an iron core material for transformers and rotary machines.
  • a grain-oriented electrical steel sheet is a steel sheet which achieves a significantly superior low iron loss by highly preferentially growing crystal grains in ⁇ 110 ⁇ 001>orientation, which is called the Goss orientation.
  • iron loss properties are regarded as important properties since they directly relate to an energy loss of a product.
  • punchability and bending workability are also important properties. That is, when iron cores of transformers and rotary machines are formed, an electrical steel sheet is formed into a predetermined shape through various processes such as punching, shearing, and bending. In addition, when a steel strip passes through a processing line in which the above various processes are performed, a steel sheet may be warped or the like in some cases. Hence, the properties described above are important.
  • a grain-oriented electrical steel sheet is manufactured by a process disclosed in paragraph [0005] of Japanese Unexamined Patent Application Publication No. 2003-41323 and the like. That is, a steel sheet obtained by rolling is processed by recrystallization annealing, and a single batch annealing called final annealing is then carried out. By this batch annealing, the secondary recrystallization is promoted, and as a result, crystal grains in the Goss orientation are highly preferentially grown.
  • a steel sheet which is wound in the form of a coil is heated in batch annealing, and in general, final annealing for manufacturing a grain-oriented electrical steel sheet is necessarily performed at a high temperature; hence, sticking occurs between parts of the steel sheet which is wound in the form of a coil.
  • a technique has been widely used in which an annealing separator primarily composed of MgO is applied so as to form a forsterite coating in annealing. It is believed that the forsterite coating is formed by reaction between MgO contained in an annealing separator and SiO 2 contained in oxides formed on a steel sheet surface (however, Fe is also contained in the coating).
  • This forsterite coating has superior annealing separation properties and has various advantageous features for the properties of a grain-oriented electrical steel sheet.
  • a hard coating tensile coating
  • the iron loss can be decreased.
  • a grain-oriented electrical steel sheet having a forsterite coating is inferior in both punchability and bending workability. That is, there have been problems in that a punching mold is worn out in a shorter time and in that burrs are formed on a sheared surface of a steel sheet. In addition, since peeling is liable to occur in bending process, superior peeling resistance on bending is required which prevents peeling even when a bending process or the like is performed after stress-relief annealing.
  • a method for changing a component of an annealing separator has been attempted, that is, a method has been attempted in which an annealing separator containing no MgO which reacts with SiO 2 present on a steel sheet surface is applied after recrystallization annealing, followed by final annealing.
  • annealing separators primarily composed of a material other than MgO there have been known an annealing separator primarily composed of alumina (powder) disclosed in Japanese Unexamined Patent Application Publication Nos. 6-136448 , 7-118750 , and 5-156362 , and an annealing separator primarily composed of alumina and/or silica disclosed in Japanese Unexamined Patent Application Publication Nos. 11-61261 and 8-134542 .
  • These annealing separators may be electrostatically sprayed onto a steel sheet or may be formed into a water slurry or a suspension using an alcohol or the like, followed by application to a steel sheet.
  • the technique disclosed in Japanese Unexamined Patent Application Publication No. 2003-41323 is to obtain the function of final annealing by performing batch annealing twice so as to promote the secondary recrystallization by first batch annealing and so as to form a forsterite coating by second batch annealing.
  • an annealing separator may be applied.
  • an annealing separator primarily composed of MgO is used in the first batch annealing after the recrystallization annealing, the formation of a forsterite coating in the second batch annealing is adversely influenced, and as a result, it becomes very difficult to obtain superior coating properties.
  • decarburization is preferably performed after the first batch annealing, a coating such as a forsterite coating disadvantageously interferes with the decarburization.
  • the present invention was made to solve the above problems and proposes an annealing separator which contains no MgO, which has superior application properties to a steel sheet and superior adhesion thereto after the application, and which can manufacture a grain-oriented electrical steel sheet without generating a dust problem and line contamination caused thereby, and in addition, the present invention also proposes an annealing method using the above annealing separator.
  • the present invention relates to a method for manufacturing a grain-oriented electrical steel sheet, which is suitably used as an iron core material of transformers and rotary machines, by using the above annealing separator.
  • the present invention proposes a method for manufacturing a grain-oriented electrical steel sheet having a forsterite coating with superior coating properties and a grain-oriented electrical steel sheet having superior workability without any forsterite coating.
  • the present invention provides a method as defined in claim 1. Preferred embodiments are set out in the dependent claims.
  • the method for manufacturing a grain-oriented electrical steel sheet may comprise a step of performing hot rolling of a slab formed from molten steel having a composition in which the content of C is 0.08 mass percent or less, the content of Si is 2.0 to 8.0 mass percent, the content of Mn is 0.005 to 1.0 mass percent, the content of Al is decreased to 150 ppm or less, and the contents of N, S, and Se are each decreased to 50 ppm or less, a step of then performing cold rolling once, or twice or more with intermediate annealing performed therebetween, to obtain a steel sheet having a final sheet thickness, a step of then performing recrystallization annealing, and a step of then performing final annealing in accordance with the annealing method described in the above (1), in which the amount of the annealing separator applied to the steel sheet before annealing in the final annealing is set to 0.005 to 5 g/m 2 per one surface.
  • the annealing separator be composed of an Al compound and a Si compound as a primary component, the ratio of the Al compound to the Si compound calculated based on Al 2 O 3 /(Al 2 O 3 +SiO 2 ) be 40 to 95 mass percent, and the annealing separator have a viscosity of 25 mPa ⁇ s or less and be in the form of a solution or a colloidal solution.
  • the Al compound is preferably at least one of an Al compound having a hydroxyl group and an organic acid group and a dehydrated product (including partly dehydrated product) of an Al compound having a hydroxyl group and an organic acid group. More preferably, the Al compound is at least one of a basic Al acetate, a basic Al formate, a basic Al chloride, a basic Al nitrate, a basic Al oxalate, a basic Al sulfamate, a basic Al lactate, and a basic Al citrate or a mixture containing two or more of the above compounds.
  • the present invention preferably provides annealing of the grain-oriented electrical steel sheet, comprising the steps of applying an annealing separator to a steel sheet and annealing the steel sheet coated with the annealing separator, wherein the annealing separator comprises an Al compound in the form of a solution or a colloidal solution and further comprises at least one compound selected from the group consisting of a Si compound, a Sr compound, a Ca compound, a Zr compound, a Ti compound, and a Ba compound, the content of the Al compound is 40 to 95 mass percent in terms of a solid component ratio represented by the following equation (2), and the viscosity of the annealing separator is 25 mPa ⁇ s or less.
  • Solid component ratio of Al compound solid component of Al compound / solid component of Al compound + solid component of said at least one compound sum
  • the annealing separator may contain at least one compound selected from the group consisting of the Si compound, the Sr compound, the Ca compound, the Zr compound, the Ti compound, and the Ba compound in the form of a solution or a colloidal solution.
  • an annealing separator having superior application properties and adhesion properties after application, it was discovered that when an annealing separator is composed of an Al compound and a stable compound at a high temperature as a primary component, and when the Al compound is present in the form of a solution or a colloidal solution, the problems described above can be solved.
  • the inventors of the present invention also found a preferable viscosity of the annealing separator, a preferable solid component ratio of the Al compound, and a preferable amount of the annealing separator applied to a steel sheet.
  • experiments performed for making the present invention will be described.
  • a steel slab was manufactured by continuous casting from a component composition in which 0.020 mass percent of C, 3.30 mass percent of Si, 0.070 mass percent of Mn, and 400 mass ppm of Sb were contained, and the contents of Al, N, S, and Se were decreased to 38 mass ppm, 33 mass ppm, 18 ppm, and less than 10 ppm (less than the analytical limit), respectively.
  • the steel slab was processed by cold rolling once, or twice or more with intermediate annealing performed therebetween, so as to obtain a steel sheet having a final sheet thickness.
  • the steel sheet thus cold-rolled was processed by recrystallization annealing and final annealing.
  • an aqueous colloidal solution solid component concentration: 3.0 mass percent
  • silica sol colloidal silica
  • baking treatment was performed at ultimate temperature of the steel sheet of 250°C, followed by spontaneous cooling. From the difference in weight of the steel sheet before the application and after the baking treatment, the amount of the annealing separator thus adhered was estimated, and this weight was regarded as an application amount of the annealing separator.
  • the steel sheet coated with the annealing separator was evaluated by visual inspection.
  • the steel sheet was washed with running water at a flow rate of approximately 1.0 m/s. Subsequently, after water was removed by a ringer roll, drying was performed at 200°C for 10 seconds. Next, the weight of the steel sheet was again measured, and the application amount of the annealing separator was again calculated. The difference in weight of the annealing separator before and after the water washing was obtained and was regarded as a peeled amount. Based on the peeled amount thus obtained, the evaluation was performed as follows.
  • Table 1 Application amount (g/m 2 ) Viscosity (mPa ⁇ s) Application properties Adhesion properties of annealing separator Peeled amount (g/m 2 ) Annealing separation effect Peeling strength (N) 0.1 3.1 ⁇ ⁇ 0.05 ⁇ 3 0.5 3.1 ⁇ ⁇ 0.20 ⁇ 0 1 3.1 ⁇ ⁇ 0.65 ⁇ 0 2 3.1 ⁇ ⁇ 1.70 ⁇ 0 3 3.1 ⁇ ⁇ 2.90 ⁇ 2
  • silica sol has a problem of adhesion properties to a steel sheet as an annealing separator. Accordingly, in order to use silica sol as an annealing separator and in order to improve the adhesion properties to a steel sheet, the effectiveness of addition of an alumina sol as a film-forming component was investigated by the inventors of the present invention.
  • an annealing separator solid component concentration: 2.0 mass percent
  • an aqueous colloidal solution primarily composed of an alumina sol (colloidal alumina) and a silica sol was applied in an application amount of 0.5 g/m 2 per one surface by a roll coater.
  • baking was performed at ultimate temperature of the steel sheet of 250°C, followed by spontaneous cooling.
  • a temperature of 850°C was maintained for 30 hours in a nitrogen atmosphere
  • a temperature of 1,000°C was maintained for 5 hours in an Ar atmosphere as the final annealing.
  • the ratio of the alumina sol to the silica sol was changed in the range of 20 to 100 mass percent based on Al 2 O 3 /(Al 2 O 3 +SiO 2 ), and the viscosity of the annealing separator was changed in the range of 3.5 to 100 mPa ⁇ s.
  • the viscosity of the annealing separator was changed by using an alumina sol having a different viscosity.
  • the viscosity of the alumina sol can be controlled, for example, by the shape of sol particles and the solid component ratio thereof.
  • the appearance of the sol particles is in the form of feathers, a high viscosity is obtained, and when the appearance is similar to a sphere (or a particle shape) or an oval (or a bar shape), a low viscosity is obtained.
  • Table 2 Alumina sol ⁇ silica sol ratio Al 2 O 3 /(Al 2 O 3 +SiO 2 ): mass% Viscosity (mPa ⁇ s) Application properties Adhesion properties of annealing separator Removed amount (g/m 2 ) Annealing separation effect Peeling strength (N) 10 3.5 ⁇ ⁇ 0.2 ⁇ 0 20 3.5 ⁇ ⁇ 0.1 ⁇ 0 40 3.5 ⁇ ⁇ 0.05 ⁇ 0 50 3.5 ⁇ ⁇ 0 ⁇ 0 75 3.5 ⁇ ⁇ 0 ⁇ 0 90 3.5 ⁇ ⁇ 0 ⁇ 0 100 3.5 ⁇ ⁇ 0 ⁇ 0 Table 3 Alumina sol ⁇ silica sol ratio Al 2 O 3 /(Al 2 O 3 +SiO 2 ): mass% Viscosity (mPa ⁇ s) Application properties Adhesion properties of annealing separator Peeled amount (g/m 2 ) Annealing separation effect Peeling strength (N) 60 3.5 ⁇ ⁇
  • an annealing separator solid component concentration: 2.5 mass percent
  • solid component concentration 2.5 mass percent
  • the viscosity of the annealing separator was set to 2.5 mPa ⁇ s and the ratio of the alumina sol to the silica sol was set to 75 mass percent based on Al 2 O 3 /(Al 2 O 3 +SiO 2 ).
  • the experimental results are shown which were obtained when the application amount was changed.
  • the application amount was excessively small, the annealing separation effect was insufficient, and sticking between steel sheets occurred.
  • the application amount was increased, the adhesion properties of the annealing separator to a steel sheet were degraded. Accordingly, in order to ensure superior adhesion properties to a steel sheet and to obtain the annealing separation effect, the application amount of the annealing separator is preferably controlled.
  • Table 4 Alumina sol ⁇ silica sol ratio Al 2 O 3 /(Al 2 O 3 +SiO 2 ): mass% Viscosity (mPa ⁇ s) Application amount (g/m 2 ) Application properties Adhesion properties of annealing separator Peeled amount (g/m 2 ) Annealing separation effect Peeling strength (N) 75 2.5 0.001 ⁇ ⁇ 0 ⁇ 100 75 2.5 0.005 ⁇ ⁇ 0 ⁇ 10 75 2.5 0.05 ⁇ ⁇ 0 ⁇ 0 75 2.5 0.5 ⁇ ⁇ 0 ⁇ 0 75 2.5 1 ⁇ ⁇ 0 ⁇ 0 75 2.5 2 ⁇ ⁇ 0 ⁇ 0 75 2.5 3 ⁇ ⁇ 0 ⁇ 0 75 2.5 6 ⁇ ⁇ 1.2 ⁇ 0
  • the restriction is generally determined at the point of time when the annealing separator is applied to a steel sheet.
  • an Al compound in the form of a solution or a colloidal solution and a stable compound at a high temperature are used, that is, as the stable compound, at least one know compound other than MgO is used which has superior high temperature stability and which does not react or is unlikely to react in batch annealing.
  • the stable compound at a high temperature may be in the form of a solution or a colloidal solution as is the Al compound. That is the annealing separator may be in the form of a solution or a colloidal solution.
  • the form of a solution means the state in which the compound is dissolved in a medium such as water or an organic solvent.
  • the form of a colloidal solution means the state in which particles of the above compound having a size of approximately 100 nm or less are stably dispersed in the above medium with the assistance of structure parts of functional groups or the like, which parts have affinity for the medium.
  • liquid used as the medium is collectively called a solvent. Since the colloidal solution does not look like suspension and is transparent, it is similar to a solution; however, when colloidal particles are present, the presence thereof can be confirmed by measurement of light scattering.
  • the primary component indicates a composition component other than an auxiliary agent and an additive which will be described later.
  • the primary component occupies approximately 65 mass percent or more of the entire annealing separator component (that is, a material forming a solute or colloid) after drying and preferably occupies 75 mass percent or more.
  • the liquid used as a solvent is not particularly limited, and either water or an organic solvent may be used.
  • the organic solvent although methanol, isopropanol, ethylene glycol or the like may be generally used, the organic solvent is not limited thereto.
  • Water is preferably used as a solvent in view of cost, wide selectability of the compound, and the like. In this case, in order to adjust liquid properties or the like, approximately 50 mass percent or less of an organic solvent may be mixed with water.
  • an annealing separator which contains water as a primary solvent is called an aqueous annealing separator.
  • the annealing separator described above is very effective.
  • the reason at least two types of compounds are used as a primary component of the annealing separator are to obtain a significant annealing separation effect by the stable compound at a high temperature and also to obtain a superior film-forming effect by the Al compound in the form of a solution or a colloidal solution.
  • an annealing separator for steel sheets can first be obtained having superior application properties and adhesion properties to a steel sheet after application, and in particular, the properties required for an annealing separator for grain-oriented electrical steel sheets can be satisfied.
  • the Al compound is limited to a compound which forms colloid in a solvent such as water. That is, when the Al compound is not in a colloidal state, the film-forming effect cannot be obtained, and as a result, the adhesion properties cannot be obtained. For example, when alumina in the form of a slurry or suspension is applied, the film is not formed.
  • the particle diameter of the colloid of the Al compound is preferably set to approximately 50 nm or less. As for the lower limit, there is not preferable particle diameter limit, and even in the vicinity of the analytical limit, a sufficient effect can be obtained.
  • the Al compound is preferably an aluminum compound having a hydroxyl group and an organic acid group and/or a dehydrated product (may include a partly dehydrated product, and hereinafter, the dehydrated product is the same as described above) of the above Al compound. More preferably, the Al compound is Al, an aluminum compound having a hydroxyl group and an organic acid group and/or a dehydrated product thereof.
  • a basic Al acetate for example, there may be mentioned at least one of a basic Al acetate, a basic Al formate, a basic Al chloride, a basic Al nitrate, a basic Al oxalate, a basic Al sulfamate, a basic Al lactate, and a basic Al citrate or a mixture containing at least two of the above compounds.
  • the basic aluminum acetate has a molecular formula represented by Al x (OH) y (CH 3 COO) z , (x, y, and z are 1 or more), and in particular, Al 2 (OH) 5 (CH 3 COO) is preferable.
  • This compound can be present in the form of from molecules dissolved in a solvent to colloidal particles of approximately several nanometers and can be preferably used as a coating raw material. According to a thermal analysis, a large peak because of dehydration reaction is observed at 200 to 230°C, and a network structure between molecules is formed through dehydration condensation by heating, thereby forming a film.
  • the basic aluminum acetate or the like may be partly or entirely dehydrated.
  • a material similar to that used for the aqueous annealing separator may also be used.
  • a known compound may be used and is not particularly limited; however, for example, a Si compound, a Sr compound, a Ca compound, a Zr compound, a Ti compound, and a Ba compound may be mentioned.
  • a particular compound an oxide such as SiO 2 , SrO, TiO 2 , BaO, or CaO may be mentioned.
  • a compound is preferably used which is chemically modified to have a hydrophilic group such as a hydroxyl group.
  • a compound in the state in which the surface thereof is covered with a known hydrophilic material in a solvent there may be used a compound in the state in which the surface thereof is covered with a known hydrophilic material in a solvent.
  • the stable compound at a high temperature may be designed by using a lipophilic group or the like.
  • the high temperature in the case of the stable compound at a high temperature indicates an annealing temperature; however, for a grain-oriented electrical steel sheet, a compound which is stable at 1,200°C is satisfactory, and a compound which is stable at 1,300°C is more preferable.
  • a compound which neither reacts by itself nor reacts with a steel sheet or an oxide (such as SiO 2 , FeO, Fe 3 O 4 , or Fe 2 SiO 4 ) on the surface thereof at the temperatures mentioned above may be used as the stable compound at a high temperature.
  • a Si compound is preferable in view of the application properties, annealing separation properties, and the like.
  • the Si compound silica in the form of colloid, that is, so-called colloidal silica is particularly preferable because of a relatively low cost in addition to high stability with an alumina sol.
  • the colloidal silica is inorganic colloid primarily composed of SiO 2 and is often amorphous.
  • non-colloidal Al compound an Al compound which is not in the form of a solution nor a colloidal solution, such as alumina particles, is stable at a high temperature, the effect of improving the application properties of the Al compound in the form of a solution or a colloidal silica is not significant.
  • a compound which is stable at a high temperature other than the non-colloidal Al compound is preferably contained.
  • the non-colloidal Al compound is not taken into calculation of the solid component ratio which will be described later.
  • the Al compound preferably has a solid component ratio of 40 to 95 mass percent which is represented by the following equation (1).
  • Solid component ratio of Al compound solid component of Al compound / solid component of Al compound + solid component of stable compound at a high temperature sum
  • the solid component of the Al compound is calculated based on the form of Al 2 O 3 and that of the stable compound at a high temperature is calculated based on the form of a primary compound obtained after baking.
  • a silica sol silica, that is, SiO 2 is a primary compound
  • titania titania, that is, TiO 2 is a primary compound.
  • a baking step is not particularly provided, calculation is performed based on a primary compound which is obtained when baking treatment is performed.
  • the solid component indicates the quantity contained in an annealing separator component after drying.
  • the solid component ratio of the Al compound is 40 mass percent or less, the Al compound which is a film-forming component is not sufficient, and hence the adhesion properties of the annealing separator become insufficient.
  • the solid component ratio is more than 95 mass percent, the amount of a highly reactive Al compound is excessively increased, and as a result, the coating liquid is not stabilized. Hence, a uniform coating cannot be formed, and as a result, a product with defective appearance is obtained.
  • the solid component ratio of the Al compound is preferably 50 mass percent or more, more preferably 60 mass percent or more, and even more preferably 70 mass percent or more.
  • the solid component ratio of the Al compound can be represented by the following equation (2).
  • Solid component ratio of Al compound solid component of Al compound / solid component of Al compound + ( solid component of said at least one compound sum
  • solid components of the above compounds are preferably calculated based on the following respective forms:
  • the ratio of the Al compound to the Si compound calculated based on Al 2 O 3 /(Al 2 O 3 +SiO 2 ) is preferably set to 40 to 95 mass percent.
  • the viscosity of the annealing separator is set to 25 (mPa ⁇ s) or less. When the viscosity is more than 25 (mPa ⁇ s), the application properties are seriously degraded, so that uniform application of the annealing separator to a steel sheet is interfered with. In addition, as a result, part which is not coated with the annealing separator is generated, and hence adhesion between steel sheets occurs in final annealing.
  • the viscosity of the present invention is a viscosity of the annealing separator at a liquid temperature of 25°C measured by an Oswald viscometer.
  • S constitutional substance
  • S-containing compound a compound containing S
  • superior magnetic properties can be stably imparted to a grain-oriented electrical steel sheet.
  • S-containing compound is decomposed in batch annealing, and that the S then enters the steel and is segregated in grain boundaries. That is, it is believed that by the S thus segregated, grain growth is suppressed and that as a result, secondary recrystallization is stabilized.
  • the amount of a S-containing compound for addition is preferably set to approximately 25 mass percent or less in terms of the solid component ratio to the annealing separator component after baking.
  • evaluation is performed based on the solid component ratio of a S-containing compound which is to be formed when baking treatment is performed.
  • the S-containing compound is not particularly limited; however, an inorganic S compound such as a sulfate (including a sulfite) or a metal sulfide is preferably used.
  • an inorganic S compound such as a sulfate (including a sulfite) or a metal sulfide is preferably used.
  • strontium sulfate, magnesium sulfate, and magnesium sulfide may be mentioned.
  • an annealing separator various methods generally used for industrial purposes, such as roll coater, flow coater, spray, and knife coater, may be used.
  • the annealing separator of the present invention is baked by heating after application.
  • a baking method for example, a general method, such as a hot-wind type, an infrared type, or an induction heating type method, may be used. Conditions of baking treatment may be determined in consideration of various situations; however, temperature is in the range of approximately 150 to 400°C, and a preferable time is in the range of approximately 1 to 300 seconds.
  • additives such as a surfactant and/or a corrosion inhibitor may also be blended.
  • the content of an additive is preferably set to 10 mass percent or less to the annealing separator component after baking in order to maintain a sufficient annealing separation effect as the annealing separator.
  • surfactant commercial available nonionic, anionic, cationic surfactants may all be used.
  • a corrosion inhibitor type is not particularly limited, and commercially available products may be used.
  • the annealing separator of the present invention is not prohibited to be applied to other steel sheets.
  • the annealing separator of the present invention is effective when a steel strip wound in the form of a coil is heated in a furnace; however, it may also be applied to the case in which steel sheets which are piled up are processed by heat treatment.
  • molten steel or steel slab To the composition of a product sheet and that of a starting material (molten steel or steel slab), known components preferably used for a grain-oriented electrical steel sheet may all be applied.
  • molten steel components of a representative composition the reasons for restriction of the respective components will be described.
  • the content of C is more than 0.08 mass percent, it becomes difficult to decrease the content to 50 mass ppm or less (at which no magnetic aging occurs) in a manufacturing process, and hence the content is preferably set to 0.08 mass percent of less.
  • the lower limit is not necessarily determined, from an industrial point of view, the lower-limit is approximately 5 mass ppm.
  • Si is an effective element which increases the electrical resistance of steel and which improves the iron loss, and in order to obtain the above effect, the content is preferably set to 2.0 mass percent or more.
  • the content is more than 8.0 mass percent, the workability and magnetic flux density are degraded, and hence the upper limit is preferably set to 8.0 mass percent.
  • a preferable content of Si is in the range of 2.0 to 8.0 mass percent.
  • Mn is an effective element which improves the hot workability, and the content is preferably set to 0.005 mass percent or more.
  • a preferable content of Mn is 1.0 mass percent or less.
  • the content of Mn is preferably set in the range of 0.005 to 1.0 mass percent.
  • the content of Al is preferably decreased to 150 mass ppm or less, and the contents of N, S, and Se are also preferably decreased to 50 mass ppm or less.
  • the elements mentioned above are preferably decreased as small as possible in view of magnetic properties, and for example, the content of Al is more preferably decreased to 100 mass ppm or less.
  • the cost may be increased in some cases; hence, when the components in the range described above are allowed to remain, any problems may not occur at all.
  • the lower-limit content of each element determined from a cost reduction point of view is currently approximately 10 mass ppm.
  • the above elements are inversely added in accordance with the inhibitor which is to be used. For example, it is generally performed that when AlN is used as an inhibitor, 0.015 to 0.04 mass percent of Al and 0.005 to 0.015 mass percent of N are added; when BN is used, 0.001 to 0.006 mass percent of B and 0.005 to 0.015 mass percent of N are added; when MnSe and/or MnS is used, 0.005 to 0.06 mass percent of at least one of Se and S is added.
  • Sb and/or Sn in a total amount of approximately 0.005 to 0.1 mass percent is preferably added to a grain-oriented electrical steel sheet since the magnetic properties are further improved.
  • the balance is preferably composed of iron and inevitable impurities.
  • a slab having a common dimension may be manufactured by a common ingot casting method or continuous casting method or a thin cast slab (so-called thin slab) having a thickness of 100 mm or less may be manufactured by a direct casting method.
  • a slab is reheated and then hot-rolled by a common method; however, without performing heating after casting, hot rolling may be directly performed.
  • hot rolling may be performed, or without performing hot rolling, subsequent steps may be performed.
  • the hot-rolled steel sheet is then annealed (normalizing) whenever necessary.
  • hot-rolled steel sheet annealing is preferably performed.
  • the temperature for hot-rolled steel sheet annealing is preferably increased to 800°C or more.
  • the hot-rolled steel sheet annealing temperature is preferably set to 1,100°C or less.
  • the hot-rolled steel sheet annealing temperature is preferably set in the range of 800 to 1,100°C.
  • a preferable annealing time of the hot-rolled steel sheet annealing is 1 to 300 seconds.
  • recrystallization annealing is performed.
  • intermediate annealing is performed between cold rolling steps.
  • the intermediate annealing is preferably performed at 900 to 1,200°C for approximately 1 to 300 seconds.
  • the temperature of cold rolling may be increased to 100 to 250°C. This is sometimes called warm rolling; however, in the present invention, this rolling is regarded as one type of cold rolling.
  • aging treatment at a temperature in the range of 100 to 250°C may be performed once or more.
  • the recrystallization annealing is mainly performed in order to form a primary recrystallization texture and is preferably performed by continuous annealing.
  • a humid atmosphere is used; however, when decarburization is not required, a dry atmosphere may be used.
  • the temperature is 750 to 1,100°C and the time is approximately 1 to 300 seconds.
  • the content of C in a steel sheet in the secondary recrystallization annealing (final annealing, or a first batch annealing step when the final annealing is performed by two batch annealing steps) is controlled in the range of 100 to 250 mass ppm, particularly in a grain-oriented electrical steel sheet containing no inhibitor, it is preferable in order to improve the magnetic flux density.
  • the control of the amount of C may be performed by the recrystallization annealing or may be subsequently performed in a different step.
  • a technique in which the amount of Si is increased by siliconizing method may be applied to a steel sheet after, for example, the recrystallization annealing.
  • the annealing separator of the present invention is applied before or after the recrystallization annealing.
  • a conventional annealing separator Since a conventional annealing separator has inferior adhesion properties to a steel sheet, application thereof before recrystallization annealing cannot be performed since line contamination occurs by peeling of the annealing separator during the recrystallization annealing. This situation is similar to the case of an annealing separator primarily composed of MgO which requires long-time heating for forming a coating. However, since the annealing separator of the present invention has superior adhesion properties to a steel sheet and will not cause line contamination by peeling, the application may be performed either before or after the recrystallization annealing.
  • the application amount of the annealing separator of the present invention is preferably set to 0.005 g/m 2 or more in order to obtain sufficient effect of preventing adhesion between steel sheets.
  • the application amount thereof is preferably set to 5 g/m 2 or less.
  • the application amount of the annealing separator is preferably set in the range of 0.005 to 5 g/m 2 .
  • a more preferable lower limit is 0.05 g/m 2 and a more preferable upper limit is 2 g/cm 2 .
  • an amount of the annealing separator which is outside the range described above, may also be used.
  • the annealing separator may be applied only to one surface of a steel sheet; however, in order to reliably obtain the effect, application is preferably performed on the two surfaces.
  • the change in composition or the like of the annealing separator between the front and the rear surfaces of a steel sheet is not prohibited; however, from a manufacturing point of view, the same annealing separator is preferably applied to the two surfaces.
  • final annealing is performed by batch annealing.
  • the purpose of the final annealing is to promote the secondary recrystallization and to decrease impurities (purification).
  • the annealing conditions known conditions which can achieve those purposes may be used.
  • a preferable final annealing temperature is approximately 750 to 1,300°C
  • the temperature may be set to approximately 750 to 1,000°C in the first half and may be set to approximately 900 to 1,300°C in the second half.
  • the secondary recrystallization is primarily promoted in the first half, and the purification is primarily promoted in the second half.
  • a preferable final annealing time a holding time in the above temperature range is approximately 1 to 300 hours.
  • the content of C is preferably decreased, after the secondary recrystallization is performed, to 50 ppm or less at which no magnetic aging occurs.
  • a method for decreasing the content of C there may be mentioned a method in which decarburization is performed during the final annealing and a method in which a decarburization step is additionally performed after the final annealing.
  • high temperature annealing at 1,000°C or more in an atmosphere containing hydrogen may be performed during the final annealing, and in particular, during the second half thereof.
  • the decarburization step additionally performed after the final annealing, for example, (1) annealing (decarburization annealing) in an oxidizing atmosphere, (2) surface polishing for mechanically removing graphite in a surface layer, and (3) chemically removing graphite in a surface layer such as electrolytic washing, chemical polishing or plasma irradiation are effectively performed.
  • annealing decarburization annealing
  • surface polishing for mechanically removing graphite in a surface layer
  • chemically removing graphite in a surface layer such as electrolytic washing, chemical polishing or plasma irradiation are effectively performed.
  • the reasons the decarburization can be performed by the methods (2) and (3) are that by the end of the final annealing, C in the form of graphite precipitates in the surface layer of a steel sheet, and decarburization inside the steel is already completed.
  • a dense or firm coating layer is formed on the surface in the final annealing (for example, when a conventional annealing separator primarily composed of MgO is used), surface activation is interfered with, and as s result, the precipitation of graphite in a surface layer of a steel sheet is also interfered with.
  • the coating formed from the annealing separator of the present invention has superior adhesion properties; however, the precipitation of graphite in a surface layer of a steel sheet is not adversely influenced although the reason for this has not been understood, and hence the above decarburization method can be preferably used.
  • the shape is effectively corrected by applying a tensile strength through flattening annealing.
  • the decarburization may be simultaneously performed (one type of method (1) described above).
  • the technique for increasing the amount of Si by a siliconizing method may be further employed after the final annealing. This technique is effectively used in order to further decrease the iron loss.
  • an organic coating containing a resin is preferably used as the insulating coating.
  • an inorganic coating is preferably used as the insulating coating.
  • a step only for removing the annealing separator is not particularly required.
  • first batch annealing is performed in order to realize the secondary recrystallization.
  • the annealing conditions known annealing conditions which can promote the secondary recrystallization may be used.
  • the temperature is approximately 750 to 1,100°C and the time is approximately 1 to 300 hours.
  • subscale formation is first performed by continuous annealing.
  • first batch annealing is performed while a predetermined amount of C is contained in order to improve the magnetic properties
  • decarburization is preferably simultaneously performed.
  • annealing conditions time, temperature, atmosphere, and the like
  • known annealing conditions may be used so as to easily and stably form the forsterite coating in a subsequent batch annealing.
  • a preferable annealing temperature is approximately 750 to 1,000°C
  • a preferable annealing time is approximately 1 to 300 seconds
  • a preferable atmosphere is an oxidizing atmosphere containing a hydrogen gas and a nitrogen gas.
  • a step of removing the annealing separator of the present invention is not necessary. That is, even when the forsterite coating is applied to a steel sheet with the annealing separator of the present invention provided therebetween, the adhesion properties of the forsterite coating are superior, and in addition, the purification is not interfered with by the presence of the annealing separator of the present invention.
  • an annealing separator primarily composed of MgO is applied to the surface of the steel sheet, followed by the second batch annealing. Since this second batch annealing is performed for forming the forsterite coating and for the purification to reduce impurities, known annealing conditions which can achieve these two purposes may be used.
  • a preferable annealing temperature is approximately 900 to 1,300°C, and a preferable annealing time is approximately 1 to 300 hours.
  • the annealing separator primarily composed of MgO a known compound may be used.
  • a compound is preferably used in which approximately 80 to 99 mass percent of MgO as a solid component and, whenever necessary, at least one of TiO 2 , SrSO 4 , MgSO 4 and the like as the balance are contained.
  • the technique may be further used in which the amount of Si is increased by a siliconizing method.
  • a tensile coating is finally applied whenever necessary, followed by baking.
  • the shape may be corrected by flattening annealing, and furthermore, flattening annealing which simultaneously bakes the tensile coating may also be performed.
  • the grain-oriented electrical steel sheet of the present invention indicates an electrical steel sheet in which the secondary recrystallization is realized.
  • the case in which Cube oriented grains ( ⁇ 100 ⁇ 001>orientation or ⁇ 100 ⁇ 011>orientation) are recrystallized is also included in Claims of the present invention.
  • a texture in which crystal grains are preferentially oriented in the Cube orientation can be formed by a known method, and for example, it may be performed by the control of a rolling texture; however, a process after the recrystallization annealing is approximately similar to that for realizing the secondary recrystallized grains which are preferentially oriented in the Goss orientation.
  • first batch annealing was performed.
  • An annealing separator shown in Table 5 was applied before or after the recrystallization annealing.
  • the application of the annealing separator was performed by a roll coater, and baking treatment was then performed at ultimate temperature (sheet temperature) of the steel sheet of 250°C, followed by spontaneous cooling.
  • the baking was performed by direct flame of a propane gas.
  • the first batch annealing was performed at 850°C for 40 hours in a nitrogen atmosphere, so that the secondary recrystallization was completed.
  • annealing separator used for the second batch annealing a compound containing 95 mass percent of MgO and 5 mass percent of TiO 2 as a solid component was used. Subsequently, the second batch annealing was performed at 1,200°C for 5 hours in a dry hydrogen atmosphere.
  • the tensile coating was composed of a compound containing phosphoric acid, chromic acid, and colloidal silica and was baked at a temperature of 800°C.
  • the stress-relief annealing was performed at 800°C for 3 hour in a nitrogen atmosphere.
  • Table 5 shows the components of the annealing separator and the application conditions thereof.
  • Annealing separators containing powdered SiO 2 and/or Al 2 O 3 as a primary component other than No. 26 were applied in the form of an aqueous slurry, and No. 26 was suspended in an alcohol so as to have a solid component of 5 mass percent and was then applied by spraying.
  • annealing separators primarily composed of a compound other than a powder were diluted with water to form a colloidal solution, followed by application.
  • As an auxiliary agent 3 percent by weight of strontium sulfate, magnesium sulfate, or magnesium sulfide was added as shown in the table.
  • a solid component other than that shown in Table 5 was not added; however, whenever necessary, 0.5 mass percent or less of a surfactant (non-ionic type) or the like was added.
  • the order of the step of applying the annealing separator (classification was made whether the application was performed before or after the recrystallization annealing), the application properties of the annealing separators, the adhesion properties thereof after drying, and the annealing separation effect after the first batch annealing are shown in Table 6.
  • Table 7 shows the magnetic properties, forsterite coating properties, and contents (in base iron, that is, each content was obtained by analysis performed after a coating on a steel sheet surface was removed) of Al, C, N, S, and Se after the second batch annealing, which were obtained when the samples coated with the annealing separators of the present invention were processed by the subsequent steps to form product sheets.
  • the forsterite coating properties were evaluated by a minimum bending radius at which coating peeling was not generated when a sample processed by stress-relief annealing was wound around a cylinder.
  • the magnetic properties were measured in accordance with JIS C2550 using an Epstein test piece having a size of 30 ⁇ 300 mm.
  • B 8 indicates a magnetic flux density (T) at a magnetic force of 800 A/m
  • W 17/50 indicates an iron loss value (W/kg) at a frequency of 50 Hz and at a maximum magnetic flux density of 1.7 T.
  • a steel slab containing no inhibitor-forming elements was manufactured by continuous casting, in which 0.019 mass percent of C, 3.28 mass percent of Si, 0.073 mass percent of Mn, and 330 mass ppm of Sb were contained, and in which the contents of Al, N, S, and Se were decreased to 38 mm ppm, 30 mass ppm, 18 mass ppm, and less than 10 mass ppm (lower than the analytical limit), respectively.
  • the balance was iron and inevitable impurities.
  • the steel slab was hot-rolled to form a hot-rolled steel sheet having a thickness of 2.0 mm, followed by hot-rolled steel sheet annealing at 1,050°C for 60 seconds.
  • a cold-rolled steel sheet having a thickness of 0.30 mm was formed by cold rolling, followed by recrystallization annealing at 900°C for 10 seconds in a dry atmosphere having a dew point of -45°C.
  • the first batch annealing was performed.
  • the annealing separator was applied before or after the recrystallization annealing according to Table 8.
  • the application of the annealing separator was performed by a roll coater, and baking treatment was then performed at ultimate sheet temperature of 250°C, followed by spontaneous cooling.
  • the baking was performed by direct flame of a propane gas.
  • the first batch annealing was performed at 865°C for 50 hours in a nitrogen atmosphere, so that the secondary recrystallization was completed.
  • annealing separator primarily composed of MgO was then applied. Since the first batch annealing was performed while 100 to 150 mass ppm of C remained, in the continuous annealing performed for this subscale formation, decarburization was also simultaneously performed. The continuous annealing was performed at 850°C for 80 seconds in an oxidizing atmosphere having a dew point of 60°C.
  • the annealing separator used in this example was an annealing separator containing 92.5 mass percent of MgO and 7.5 mass percent of TiO 2 as a solid component.
  • the second batch annealing was performed.
  • high-temperature annealing at approximately 1,200°C required for purification of an inhibitor component was not necessary, and annealing may be performed under conditions in which the forsterite coating can be formed.
  • the second batch annealing was performed at a temperature of 1,100°C, which was lower than that used in the past, for 5 hours, and the atmosphere was dry hydrogen.
  • the tensile coating was composed of a compound containing phosphoric acid, chromic acid, and colloidal silica and was baked at a temperature of 800°C.
  • the stress-relief annealing was performed at 800°C for 3 hour in a nitrogen atmosphere.
  • the components and application conditions of the annealing separator the conditions of the corresponding Nos. shown in Table. 5 were performed as was the case of Example 1.
  • Table 8 shows the order of the step of applying the annealing separator (before or after the recrystallization annealing), application properties of the annealing separator, adhesion properties thereof after drying, and annealing separation effect after the first batch annealing.
  • the steel manufactured by the method of the present invention showed superior application properties of the annealing separator, adhesion properties thereof after drying, and annealing separation effect after the first batch annealing.
  • the annealing separator of the present invention can be effectively applied to a composition type which contains no inhibitor.
  • Table 9 shows the magnetic properties, forsterite coating properties, and contents of Al, C, N, S, and Se after the second batch annealing, which were obtained when the samples coated with the annealing separators of the present invention were processed by the subsequent steps to form product sheets.
  • the measurement methods of the respective properties were the same as those in Example 1.
  • a cold-rolled steel sheet having a thickness of 0.27 mm was formed by cold rolling, followed by recrystallization annealing at 880°C for 10 seconds in a dry atmosphere having a dew point of -45°C. Subsequently, the final annealing was performed.
  • the annealing separator was applied before or after the recrystallization annealing in accordance with Table 10.
  • the application of the annealing separator was performed by a roll coater, and baking was then performed at ultimate sheet temperature of 250°C, followed by spontaneous cooling.
  • the baking was performed by direct flame of a propane gas.
  • purification was performed at 1,200°C for 5 hours in a H 2 atmosphere.
  • the components and application conditions of the annealing separator the conditions of the corresponding Nos. shown in Table. 5 were performed as was the case of Example 1.
  • an insulating coating film As the insulating coating film, a chromate insulating coating film containing an organic resin, which has been generally used, was used, and baking was performed at 300°C. The stress-relief annealing was performed at 750°C for 2 hours in a nitrogen atmosphere.
  • Table 10 shows the application properties of the annealing separator, adhesion properties thereof after drying, annealing separation effect after the final annealing, magnetic properties, insulating coating properties, and contents of Al, C, N, S, and Se after the final annealing.
  • the viscosity of the annealing separator was outside of the present invention, the application properties were seriously inferior, and sticking occurs between parts of a steel sheet at which application was not performed.
  • Nos. 12 and 15 the ratio of the Al compound to the silicon compound was outside of the present invention.
  • the amount of the Al compound, which was a film-forming component was small, the adhesion properties of the annealing separator to a steel sheet were inferior.
  • the amount of a highly reactive Al compound was large, the coating liquid was not stabilized, and hence a uniform coating could not be formed. As a result, appearance defects occurred.
  • a steel slab containing no inhibitor-forming elements was manufactured by continuous casting, in which 0.018 mass percent of C, 3.32 mass percent of Si, 0.070 mass percent of Mn, and 300 mass ppm of Sb were contained, and in which the contents of Al, N, S, and Se were decreased to 40 mm ppm, 25 mass ppm, 15 mass ppm, and less than 10 mass ppm, respectively.
  • the balance was iron and inevitable impurities.
  • the steel slab was hot-rolled to form a hot-rolled steel sheet having a thickness of 1.8 mm, followed by hot-rolled steel sheet annealing at 950°C for 60 seconds.
  • the annealing separator was applied before or after the recrystallization annealing in accordance with Table 11.
  • the application of the annealing separator was performed by a roll coater, and baking was then performed at ultimate sheet temperature of 250°C, followed by spontaneous cooling.
  • the baking was performed by direct flame of a propane gas.
  • a temperature of 1,000°C was maintained for 5 hours in an Ar atmosphere.
  • decarburization annealing was performed in an oxidizing atmosphere, so that the content of C in base iron was decreased.
  • an insulating coating film As the insulating coating film, a chromate insulating coating film containing an organic resin, which has been generally used, was used, and baking was performed at 300°C. The stress-relief annealing was performed at 750°C for 2 hours in a nitrogen atmosphere.
  • Table 11 shows the application properties of the annealing separator, adhesion properties thereof after drying, annealing separation effect after the final annealing, magnetic properties, insulating coating film properties, and contents of Al, C, N, S, and Se after the final annealing.
  • the steel to which the annealing separator of the present invention was applied showed superior results regardless of the order of the step of applying the annealing separator.
  • annealing separators shown in Table 12 grain-oriented electrical steel sheets were manufactured.
  • the manufacturing process was as shown in Table 13, processes A and B (method by performing final annealing once) used the steel slab and manufacturing conditions of Example 3, and processes C and D (method by performing batch annealing twice) used the steel slab and manufacturing conditions of Example 1.
  • the annealing separator components other than the primary component and application conditions were the same as those in Example 1. Since scattering was not practically observed by a scattering method in No. 6, the annealing separator was practically regarded as a solution.
  • the annealing separators and the application conditions were as those of No. 13 shown in Table 5.
  • the annealing separator for grain-oriented electrical steel sheets, according to the present invention has superior application properties and adhesion properties to a steel sheet, and in an annealing separator application step and subsequent steps performed thereafter, stable operation can be ensured.
  • the annealing separator of the present invention has superior operating properties, such that while the adhesion properties are maintained, purification and decarburization can be performed without causing any problems and, in addition, a step of removing the coating is not required.
  • this annealing separator When this annealing separator is applied to a process for manufacturing a grain-oriented electrical steel sheet, a grain-oriented electrical steel sheet having superior magnetic properties and forsterite coating properties and a grain-oriented electrical steel sheet having superior magnetic properties and workability without forsterite coating can be easily manufactured.

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Claims (9)

  1. Verfahren zur Herstellung eines kornorientierten Elektrostahlblechs, umfassend die Schritte:
    a) Bilden eines Stahlblechs mit einer endgültigen Blechdicke durch Walzen einer Bramme, welche aus geschmolzenem Stahl hergestellt ist, der 0,08 Massenprozent oder weniger C, 2,0 bis 8,0 Massenprozent Si und 0,005 bis 1,0 Massenprozent Mn enthält;
    b) Aufbringen eines Glühseparators auf das Stahlblech und Backen des mit dem Glühseparator beschichteten Stahlblechs, wobei der Glühseparator eine Al-Verbindung in Form einer Lösung oder einer kolloidalen Lösung und eine stabile Verbindung, die bei hoher Temperatur stabil ist, umfasst, und wobei die Menge des Glühseparators, der auf das Stahlblech aufgebracht ist, auf 0,005 bis 5 g/m2 je Oberfläche eingestellt ist;
    c) Schlussglühen durch Chargenglühen des nach dem Verfahrensschritt b) erhaltenen Stahlblechs; und
    d) Durchführen des Rekristallisationsglühens des Stahlblechs vor dem Verfahrensschritt b) oder nach dem Verfahrensschritt b) und vor dem Verfahrensschritt c),
    dadurch gekennzeichnet, dass
    eine Netzwerkstruktur zwischen Molekülen während des Backens von 150 °C bis 400 °C durch eine Dehydratationskondensationsreaktion der Al-Verbindung gebildet wird.
  2. Verfahren zur Herstellung eines kornorientierten Elektrostahlblechs nach Anspruch 1, gekennzeichnet durch:
    ein anschließender Schritt des kontinuierlichen Glühens des Stahlblechs; und
    einen zweiten Chargenglühschritt des Chargenglühens nach dem Aufbringen eines zweiten Glühseparators auf das Stahlblech, wobei der Glühseparator MgO.
  3. Verfahren zur Herstellung eines kornorientierten Elektrostahlblechs nach Anspruch 1 oder 2,
    wobei die Bramme eine Bramme ist, die aus geschmolzenem Stahl mit einer Zusammensetzung gebildet ist, in der der Gehalt an Al auf 150 ppm oder weniger verringert ist und der Gehalt an N, S und Se jeweils auf 50 ppm oder weniger verringert ist.
  4. Verfahren zur Herstellung eines kornorientierten Elektrostahlblechs nach einem der vorhergehenden Ansprüche,
    wobei der Verfahrensschritt a) umfasst:
    Bilden eines warmgewalzten Stahlblechs durch Warmwalzen der Bramme;
    Durchführen einer Warmgewalztenstahlblechglühung des warmgewalzten Stahlblechs, wann immer dies notwendig ist; und
    Durchführen eines Kaltwalzens, einmal oder zweimal oder mehr mit dazwischen durchgeführtem Zwischenglühen, um ein Stahlblech mit einer endgültigen Blechdicke zu erhalten.
  5. Verfahren zur Herstellung eines kornorientierten Elektrostahlblechs nach einem der vorhergehenden Ansprüche,
    wobei die Al-Verbindung mindestens eine von einer Hydroxylgruppe und einer organischen Säuregruppe aufweist und ein dehydratisiertes Produkt einer Al-Verbindung eine Hydroxylgruppe und einer organischen Säuregruppe aufweist, und
    optional zumindest eines von einem basischen Al-Acetat, einem basischen Al-Formiat, einem basischen Al-Chlorid, einem basischen Al-Nitrat, einem basischen Al-Oxalat, einem basischen Al-Sulfamat, einem basischen Al-Lactat und einem basischen Al-Citrat ist oder eine Mischung, welche mindestens zwei der obigen Verbindungen enthält;
    wobei die stabile Verbindung ausgewählt ist aus SiO2, SrO, TiO2, BaO, CaO und ZrO2 in Form einer Lösung oder einer kolloidalen Lösung; und
    wobei die Viskosität des Glühseparators 25 mPa*s oder weniger bei einer Flüssigkeitstemperatur von 25 °C beträgt, gemessen mit einem Ostwald-Viskosimeter.
  6. Verfahren zur Herstellung eines kornorientierten Elektrostahlblechs nach einem der vorhergehenden Ansprüche,
    wobei der Gehalt der AI-Verbindung 40 bis 95 Massenprozent, ausgedrückt als Festkomponentenverhältnis, dargestellt durch die folgende Gleichung, beträgt: festes Komponenteverhältnis der Al-Verbindung = ( feste Komponente der Al- Verbindung ) / { ( feste Komponente der Al- Verbindung ) + ( feste Komponente der stabilen Verbindung , die bei hoher Temperatur stabil ist Summe ) } , wobei
    Figure imgb0006
     wobei
    (1) die Feststoffkomponente der AI-Verbindung auf der Grundlage der Formel Al2O3 berechnet wird und die Feststoffkomponente der stabilen Verbindung, die bei hoher Temperatur stabil ist auf der Grundlage der Formel einer Primärverbindung berechnet wird, die beim Brennen des Glühseparators gebildet wird nach dessen Auftragung in Verfahrensschritt b), oder
    (2) wobei die festen Komponenten der Verbindungen basierend auf den folgenden jeweiligen Formen berechnet werden:
    die AI-Verbindung ... ..Al2O3, die Si-Verbindung ... ... SiO2,
    die Sr-Verbindung ... ..SrO, die Ca-Verbindung ... ..CaO,
    die Zr-Verbindung ... ..ZrO2, die Ti-Verbindung .. ... TiO2, und
    die Ba-Verbindung ... ..BaO.
  7. Verfahren zur Herstellung eines kornorientierten Elektrostahlblechs nach Anspruch 6,
    wobei die mindestens eine stabile Verbindung SiO2 in Form einer Lösung oder einer kolloidalen Lösung ist, wobei das Verhältnis der AI-Verbindung zu dem SiO2 in Form einer Lösung oder einer kolloidalen Lösung berechnet basierend auf Al2O3/(Al2O3 + SiO2) 40 bis 95 Massenprozent ist.
  8. Verfahren zur Herstellung eines kornorientierten Elektrostahlblechs nach einem der Ansprüche 5 bis 7,
    wobei der Glühseparator weiterhin S oder eine Verbindung umfasst, die S in einem Feststoffkomponentenverhältnis von 25 Massenprozent oder weniger enthält, das erhalten wird, wenn der Glühseparator nach dem Aufbringen desselben in Verfahrensschritt b) gebacken wird.
  9. Verfahren zur Herstellung eines kornorientierten Elektrostahlblechs nach Anspruch 8,
    wobei das S oder die Verbindung, die S enthält, mindestens eine ist, ausgewählt aus der Gruppe bestehend aus Sr-Sulfat, Mg-Sulfat und Mg-Sulfid.
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JP6323423B2 (ja) * 2015-09-25 2018-05-16 Ｊｆｅスチール株式会社 方向性電磁鋼板およびその製造方法
KR101850133B1 (ko) * 2016-10-26 2018-04-19 주식회사 포스코 방향성 전기강판용 소둔 분리제 조성물, 방향성 전기강판 및 방향성 전기강판의 제조방법
KR102231543B1 (ko) * 2016-11-28 2021-03-23 제이에프이 스틸 가부시키가이샤 방향성 전기 강판 및 방향성 전기 강판의 제조 방법
KR101906962B1 (ko) * 2016-12-22 2018-10-11 주식회사 포스코 방향성 전기강판용 소둔 분리제 조성물, 방향성 전기강판 및 방향성 전기강판의 제조방법
WO2020145316A1 (ja) * 2019-01-08 2020-07-16 日本製鉄株式会社 方向性電磁鋼板、方向性電磁鋼板の製造方法、及び、方向性電磁鋼板の製造に利用される焼鈍分離剤

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EP1698706B1 (de) 2017-08-16
TW200525042A (en) 2005-08-01
TWI272311B (en) 2007-02-01
ES2673149T3 (es) 2018-06-20
CN100513597C (zh) 2009-07-15
EP1698706A4 (de) 2007-05-30
KR100774229B1 (ko) 2007-11-07
EP2559775A1 (de) 2013-02-20
WO2005054523A1 (ja) 2005-06-16
CN1890390A (zh) 2007-01-03
KR20060103517A (ko) 2006-10-02
EP1698706A1 (de) 2006-09-06
ES2643750T3 (es) 2017-11-24

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