EP0588342B1 - Tôle d'acier électrique à grains orientés et matériau à haute densité de flux magnétique et procédé pour leur fabrication - Google Patents

Tôle d'acier électrique à grains orientés et matériau à haute densité de flux magnétique et procédé pour leur fabrication Download PDF

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EP0588342B1
EP0588342B1 EP93114924A EP93114924A EP0588342B1 EP 0588342 B1 EP0588342 B1 EP 0588342B1 EP 93114924 A EP93114924 A EP 93114924A EP 93114924 A EP93114924 A EP 93114924A EP 0588342 B1 EP0588342 B1 EP 0588342B1
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percent
flux density
magnetic flux
steel sheet
high magnetic
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EP0588342A1 (fr
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Kunihide c/o Nippon Steel Corporation Takashima
Ryutarou c/o Nippon Steel Corporation Kawamata
Yoshio c/o NIPPON STEEL CORPORATION Nakamura
Isao c/o Nippon Steel Corporation Iwanaga
Norito C/O Nippon Steel Corporation Abe
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Nippon Steel Corp
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Priority claimed from JP28648692A external-priority patent/JP3324044B2/ja
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    • 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
    • H01F1/147—Alloys characterised by their composition
    • H01F1/14766—Fe-Si based alloys
    • H01F1/14775—Fe-Si based 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
    • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • 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 of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1216—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the working steps
    • C21D8/1222—Hot rolling
    • 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 of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1216—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the working steps
    • C21D8/1233—Cold rolling
    • 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 of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1244—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment
    • C21D8/1261—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment following hot rolling
    • 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 of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1244—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment
    • C21D8/1266—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment between cold rolling steps
    • 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 of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1294—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a localised treatment

Definitions

  • This invention relates to grain-oriented electrical steel sheet and material having very high magnetic flux density for use in the cores of transformers and the like in which ⁇ 110 ⁇ [001] Goss texture orientation is promoted to a high level, and a method of manufacturing same.
  • grain-oriented electrical steel sheet is used primarily for the core material of transformers and other electrical devices, and with respect to magnetic properties therefore has to have good excitation and core loss characteristics.
  • a B 8 (magnetic flux density at a magnetic field strength of 800 A/m) value is used to express excitation characteristics numerically and core loss characteristics are expressed as a W 17/50 (core loss per kilogram of material that has been magnetized to 1.7 tesla at 50 Hz) value.
  • Core loss consists of hysteresis loss and eddy current loss.
  • Hysteresis loss depends on such factors as crystal orientation of the steel sheet (in other words, magnetic flux density), purity and internal stress, while factors such as electrical resistance, sheet thickness, grain size, magnetic domain size and steel sheet coating tension contribute to the eddy current loss.
  • JP-B-51-12451 and JP-B-53-28375 describe methods for improving the core loss characteristics that a tension coating imparts to steel sheet, but the tensioning effect of these depends on the product orientation, which is to say, the magnetic flux density, and as described in pages 2981 to 2984 of the Journal of Applied Physics, Vol. 41 No. 7 (June 1970), the higher the magnetic flux density B 8 the greater the tensioning effect becomes.
  • B 8 the higher the magnetic flux density
  • this method stably provided a product with a very high magnetic flux density B 8 that far exceeded 1.92 tesla.
  • the object of the present invention is to provide a grain-oriented electrical steel sheet and material having very high magnetic flux density and a method of manufacturing same, in place of the above described core loss reduction means.
  • the present inventors succeeded in stably obtaining a product having a very high magnetic flux density higher than the conventional 1.92 tesla, and upon analyzing the product discovered the first commercial means for obtaining very high magnetic flux density within the limits of the secondary recrystallization grain shape and the slope between ideal Goss orientation.
  • the inventors carried out various studies on the conditions needed to provide a product with very high magnetic flux density, and by controlling the secondary recrystallization matrix grains and the fine secondary recrystallization grains in the secondary recrystallization matrix grains in grain-oriented electrical steel sheet containing 2.5 to 4.0 percent silicon, succeeded in developing grain-oriented electrical steel sheet having very high magnetic flux density and excellent core loss reduction effect.
  • Figure 1 shows the relationship between core loss and magnetic flux density B 8 in 3 percent silicon grain-oriented electrical steel sheet 0.30 mm thick from which the surface glass film has been removed by pickling, on which the measurement has been performed at a tension of 1.5 kg/mm 2 after laser beam irradiation at a 5 mm pitch perpendicular to the direction of cold rolling.
  • the magnetic flux density B 8 has been limited to not lower than 1.92 tesla.
  • Figure 2 shows the relationship between grain diameter in the direction of the cold rolling and magnetic flux density.
  • a magnetic flux density of 1.92 tesla or above is obtained stably in the case of grain diameters of not less than 10 mm in the secondary recrystallization grain matrix, and the attainment of 1.95 tesla is limited to grain diameters of not less than 10 mm.
  • secondary recrystallization grains less than 10 mm in diameter in the direction of the cold rolling and less than 5 mm in the direction perpendicular to the direction of cold rolling have a low magnetic flux density, and a ratio thereof that exceeds 20 percent will affect the magnetic flux density of the overall product and make it impossible to obtain a product having a magnetic flux density of 1.92 tesla or above, or a very high magnetic flux density of 1.95 tesla or above.
  • Figure 4 shows the relationship between core loss and magnetic flux density in grain-oriented electrical steel sheet product (with a tension coating) 0.30 mm thick containing 3 percent silicon.
  • a rough correspondence can be seen between magnetic flux density and core loss, but unlike in the case of the laser-beam irradiated material of Figure 1, there is considerable variation in core loss values for the same magnetic flux density.
  • the best core loss values were on a par with those of materials subjected to laser beam irradiation.
  • the matrix secondary recrystallization grains include not fewer than 50 percent fine secondary recrystallization grains having a diameter not exceeding 5 mm, a product was obtained which at a flux density of 1.92 tesla or above had a W 17/50 core loss of less than 1.0 W/kg, or at a flux density of 1.95 tesla or above had a W 17/50 core loss of 0.95 W/kg.
  • the inventors measured the fine orientation distribution features of the very high magnetic flux density grain-oriented electrical steel sheet according to the invention and, as a result, obtained the following new knowledge. Specifically, they learned that for a very high magnetic flux density grain-oriented electrical steel sheet to exhibit a flux density B 8 of not less than 1.92 tesla, even of 1.95 tesla or higher, it is necessary that among the matrix secondary recrystallization grains not fewer than 90 percent be accounted for by grains whose ⁇ 110 ⁇ [001] axes are inclined relative to the rolled surface less than 5 degrees around either the TD axis or the ND axis, and that not fewer than 90 percent be accounted for by fine secondary recrystallization grains whose ⁇ 110 ⁇ [001] axes are inclined relative to the rolled surface less than 10 degrees around either the TD axis or the ND axis. Outside these ranges it is difficult to achieve the object of the invention, namely, to obtain a very high magnetic flux density grain-oriented electrical steel sheet exhibiting a flux density B 8 of
  • the maximum diameter of the secondary recrystallization matrix grains referred to in the Summary of the Invention.
  • the limitation of the grain diameter in the direction perpendicular to the cold rolling direction to not more than 50 mm is not required from the point of the magnetic properties and was set only because larger grains are seldom obtained in actual products.
  • the grain diameter in the cold rolling direction has a bearing on the aforesaid orientation distribution. If the secondary recrystallization annealing is conducted in the flat state with respect to cut sheet segments, the limitation to not more than 100 mm set by the invention is not required as far as the relationship with grain orientation is concerned. In actual industrial production, however, the secondary recrystallization annealing is ordinarily conducted with respect to coiled sheet.
  • the invention limits the length of the secondary recrystallization grains in the cold rolling direction to not more than 100 mm.
  • the very high magnetic flux density grain-oriented electrical steel sheet is produced from the same materials as used in the production of an ordinary high flux density grain-oriented electrical steel sheet using AlN as the main inhibitor, except that it further contains 0.0005 to 0.05 percent bismuth by weight.
  • a high magnetic flux density grain-oriented electrical steel sheet using AlN as its main inhibitor is typically produced by a high temperature slab heating method in which the slab is heated to a high temperature of not lower than 1280°C at the time of hot rolling (as in the method of JP-B-46-23820) or by a low temperature slab heating method in which the slab is heated to a temperature that does not exceed 1270°C (as in the method of JP-A-59-56522). Either of these methods can be used for obtaining a very high magnetic flux density grain-oriented electrical steel sheet by addition of a small amount of bismuth in accordance with this invention.
  • the improvement in flux density is slight, while at a content of more than 0.05 percent the effect of increasing flux density saturates, making addition of more than this amount uneconomical. Since a higher bismuth content also causes edge cracking during hot rolling, its upper limit is set at 0.05 percent. From the viewpoint of flux density improvement effect and negative economic effect (the cost increase and reduced yield from edge cracking resulting from bismuth addition), it is preferable for the bismuth content to be 0.0005 to 0.01 percent.
  • JP-A-50-72817, JP-A-51-78733 and JP-A-53-39922 Addition of bismuth during production of a grain-oriented electrical steel sheet material is taught by JP-A-50-72817, JP-A-51-78733 and JP-A-53-39922.
  • these patents describe grain-oriented electrical steel sheets that fundamentally do not contain aluminum and in their specifications explain that bismuth is added in lieu of Sb, an intergranular segregation element. Therefore, differently from in the present invention, bismuth has to be added at not less than 0.01 to 0.02 percent.
  • JP-A-51-107499 and JP-A-63-100127 also teach bismuth addition.
  • a carbon content of less than 0.03 percent is undesirable because it leads to abnormal grain growth during slab heating prior to hot rolling and results in a type of defective secondary recrystallization known as streaks.
  • a carbon content of less than 0.03 percent is undesirable because secondary recrystallization becomes unstable, and when it does occur, results in very poor magnetic flux density.
  • a carbon content of more than 0.15 percent is undesirable from the industrial viewpoint because the decarburization becomes insufficient at a normal decarburization annealing time period, thus giving rise to magnetic aging in the product.
  • Si A silicon content of less than 2.5 percent is undesirable because it increases the product eddy current loss, while a silicon content of greater than 4.0 percent is undesirable because it makes cold rolling difficult at normal temperature.
  • Mn In the high-temperature slab heating method, an manganese content of 0.02 to 0.30 percent is necessary for precipitating MnS as an auxiliary inhibitor to AlN. A content below the lower limit is undesirable because the amount of inhibitor becomes insufficient. A content above the upper limit is undesirable because MnS remains undissolved during slab heating and forms coarse precipitates after hot rolling, which weakens the inhibitor effect and causes unstable secondary recrystallization. In the low-temperature slab heating method, a manganese content of 0.10 to 0.80 percent is necessary for obtaining a high magnetic flux density.
  • Acid soluble aluminum serves as a main inhibitor forming element in the production of a high magnetic flux density grain-oriented electrical steel sheet. In this point, it is also an important constituent in the present invention. An acid soluble aluminum content of less than 0.010 percent is undesirable because the amount of precipitated AlN becomes insufficient and lowers the inhibitor strength. On the other hand, at a content of more than 0.065 percent the AlN precipitates become coarse, and this also lowers the inhibitor strength.
  • N Like acid soluble aluminum, nitrogen is a main inhibitor forming element. A content outside the range of 0.0030 to 0.0150 percent disrupts the optimum inhibitor state and, as such, is undesirable.
  • Tin is an element effective for stabilizing the secondary recrystallization of thin products. It is therefore required to be present at a content of not less than 0.05 percent. Its upper limit is set at 0.05 percent because its effect saturates above this level and addition of a greater amount only increases cost.
  • Cu Copper is an element effective for improving the glass film produced by added tin. A content of less than 0.01 percent produces little effect, while a content in excess of 0.10 percent lowers the magnetic flux density of the product.
  • One feature of the present invention is the requirement that, in terms of bismuth, the bismuth addition to the molten steel be made at 100 to 5000 g per ton of molten steel.
  • the source of the bismuth is not particularly limited and may be either metallic bismuth or a substance containing bismuth.
  • the molten steel whose composition has been adjusted in the foregoing manner is cast in the ordinary manner.
  • the casting method is not particularly specified.
  • the cast steel is then hot rolled into a hot-rolled coil.
  • the slab heating temperature at the time of hot rolling preferably not less than 1280°C in the case of the high-temperature slab heating production method and not more than 1270°C in the case of the low-temperature slab heating method.
  • the hot-rolled sheet is then subjected to a single stage cold rolling or several stages of cold rolling with interpass annealing to obtain a sheet of final thickness. Since the object is to obtain a high magnetic flux density grain-oriented electrical steel sheet, the final cold rolling reduction ratio (in the case of a single stage cold rolling, the reduction rate therefore) is preferably 65 to 95 percent.
  • the inhibitor strengthening effect obtained by addition of bismuth as explained earlier maintains the inhibitor effect up to high temperatures, making it possible to selectively grow Goss nuclei at the stage where the intergranular movement accelerates in the high-temperature region. This is thought to enable secondary recrystallization to proceed.
  • the cold rolling with interpass aging described in JP-B-54-13846 is generally conducted at the time of cold rolling, with the composition of the present invention a product with excellent magnetic flux density can be obtained using the tandem cold rolling method without conducting interpass aging treatment. There is therefore no need to rely on this prior art.
  • the sheet Prior to final cold rolling, the sheet is subjected to the high-temperature annealing JP-B-46-23820 and then quenched.
  • the composition of the present invention makes it possible to extend the range of the high-temperature annealing conditions.
  • One condition that can be broadened is the annealing temperature.
  • High-temperature annealing is ordinarily conducted at a temperature of 950 to 1200°C, preferably 1050 to 1200°C, and more preferably not less than 1100°C. With the composition of the present invention, however, it is possible to obtain a product with excellent magnetic flux density even when annealing is conducted within the temperature range of 850 to 1100°C.
  • JP-B-46-23820 calls for conducting the quenching following high-temperature annealing at a cooling rate which lowers the temperature from 950°C to 400°C in 2 to 200 seconds. According to Figure 4 of this prior art reference, higher cooling rates are preferable for obtaining a product with high magnetic flux density.
  • this reference states that for obtaining a magnetic flux density of 1.92 tesla using an annealing temperature of 1150°C it is necessary for the cooling from 950°C to 400°C to be conducted in less than 20 seconds.
  • the cooling condition can be extended toward the gradual cooling side. Specifically, a product exhibiting excellent magnetic flux density can be obtained even with gradual cooling in which the temperature is lowered from 950°C to 400°C in 30 seconds or more.
  • milder cooling conditions make it easier to achieve uniform cooling and to mitigate sheet brittleness by softening the quenched structure. This relaxation of cooling conditions therefore has high industrial significance and can be expected to be vigorously pursued in conjunction with the improvement of core loss property through increased silicon content.
  • the sheet cold rolled to final product thickness is annealed and then subjected to decarburization annealing in the usual manner.
  • the decarburization annealing method is not particularly specified, it is preferably conducted for 30 seconds to 30 minutes at 700 to 900°C in a mixed gas atmosphere consisting of wet hydrogen or hydrogen and nitrogen.
  • the surface of the decarburization annealed sheet is coated with an annealing separator of ordinary composition in the ordinary manner.
  • the secondary recrystallization annealing is conducted for not less than 5 hours at a temperature of not less 1000°C in an atmosphere of hydrogen or nitrogen or a mixture of both.
  • the sheet After excess annealing separator has been removed, the sheet is subjected to continuous annealing to flatten a coil set. An insulating coating is applied and baked on at the same time. If necessary, magnetic domain fining treatment is conducted by irradiation with a laser beam or the like. The invention does not particularly specify the magnetic domain fining treatment method.
  • An electrical steel sheet slab comprising 0.06 to 0.09 percent carbon, 3.0 to 3.35 percent silicon, 0.08 percent manganese, 0.025 percent sulfur, 0.020 to 0.035 percent acid soluble aluminum, 0.008 percent nitrogen, 0 to 0.15 percent tin, 0 to 0.05 percent copper and 0.0005 to 0.05 percent bismuth and the balance of iron and unavoidable impurities, was heated to 1320°C and hot rolled to a sheet thickness of 2.3 mm. The hot rolled sheets were then cold rolled to obtain product sheets 0.30 mm and 0.23 mm thick, and between cold rollings some of these sheets were subjected to aging treatment 5 times at 200°C. Prior to final cold rolling high temperature annealing was applied at 1120°C for 2 minutes.
  • the sheets were then subjected to decarburization annealing at 850°C, coated with an annealing separator in which the main constituent was MgO and then subjected to secondary recrystallization annealing at 1200°C. After removing the remaining annealing separator, pieces measuring 60 mm by 300 mm were cut as specimens to measure magnetic properties, and the specimens were annealed at 850°C to remove internal stresses. Next, an insulating coating was applied to the specimens and baked. The magnetic properties of some of the specimens were measured after the specimens were subjected to laser beam irradiation at 5 mm intervals. After then being pickled with strong acid, specimen grain diameter and the like were measured. The results are listed in Table 1.
  • Specimens 2 and 3 containing bismuth have a magnetic flux density exceeding 1.95 tesla and a ratio of large grains in the secondary recrystallization grain matrix exceeding 80 percent, and a core loss, following laser-beam irradiation, that is far lower than 0.90 W/kg, which for an 0.30 mm thick product can be described as excellent characteristics that surpass the limits of prior art products.
  • Specimens 4 and 5 containing bismuth have a magnetic flux density exceeding 1.95 tesla, a ratio of large grains in the secondary recrystallization grain matrix exceeding 80 percent, and the matrix large grains also include are more than 50 percent fine secondary recrystallization grains, so that even without laser-beam treatment they exhibit core loss values not exceeding 0.95 W/kg, which can be described as particularly excellent characteristics for an 0.30 mm thick product.
  • Specimens 9, 10 and 11 are 0.23 mm thick products and like 0.30 mm thick products are within the scope of the present invention, and as laser-beam irradiated products exhibit particularly good characteristics.
  • Specimens were prepared from 0.30 mm thick sheet produced by the same as Example 1, and the magnetic properties of the specimens were measured. Next, after pickling with strong acid, in each specimen the orientation of 20 crystal grains was measured, using the Laue method. The results are listed in Table 2.
  • Example 4 The products obtained in Example 4 were subjected to magnetic domain fining treatment using laser-beam irradiation at a pitch of 5 mm. The results are listed in Table 5.
  • Bi content (%) Cu content (%)
  • B 8 (T) W 17/50 (W/kg) 0.009 None added 2.000 0.62 0.009 0.07 2.013 0.60
  • the specimens of this Example have a very high magnetic flux density and after grain fining attain an excellent core loss of 0.6 W/kg.
  • 0.008 percent bismuth was added to steel containing 0.06 percent carbon, 3.2 percent silicon, 0.13 percent manganese, 0.007 percent sulfur, 0.028 percent acid soluble aluminum, 0.008 percent nitrogen and 0 to 0.12 percent tin.
  • the slab was heated to 1150°C and hot rolled to a sheet thickness of 1.8 mm.
  • the hot rolled sheets were then annealed at 1100°C, and after being pickled were subjected to aging treatment 5 times at 180°C between cold rolling passes, whereby the sheets were cold rolled to a thickness of 0.23 mm, subjected to decarburization annealing at 830°C and then subjected to nitriding treatment for 30 seconds at 750°C in an atmosphere containing ammonium.
  • Table 10 shows the relationship between bismuth content, hot-rolled sheet annealing and cooling conditions, the number of bending repetitions the annealed sheets were subjected to and the magnetic flux density B 8 of the product sheets.
  • Bi content % Cooling conditions Cooling rate °C/s No. of bendings B 8 (T) None added Quenched in 100°C water 30 8 1.919 Atmospheric cooling 4 >20 1.852 0.010 Quenched in 100°C water 30 2 1.968 Forced air-cooling 13 18 1.982 Atmospheric cooling 4 >20 1.961

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Claims (10)

  1. Tôle d'acier électrique à grains orientés à très haute densité de flux magnétique produite à partir d'une brame comprenant, en poids, de 0,03 à 0,15 pour cent de carbone, de 2,5 à 4,0 pour cent de silicium, de 0,02 à 0,30 pour cent de manganèse, de 0,005 à 0,040 pour cent de soufre, de 0,010 à 0,065 pour cent d'aluminium soluble dans un acide, de 0,0030 à 0,0150 pour cent d'azote, de 0,0005 à 0,05 pour cent de bismuth optionnellement de 0,05 à 0,50 pour cent d'étain et/ou de 0,01 à 0,10 pour cent de cuivre et le reste du fer et des impuretés inévitables, et ayant une très haute densité de flux magnétique B8 non inférieure à 1,92 tesla dans laquelle, pas moins de 80 pour cent en superficie sont constitués de grains de recristallisation secondaire de matrice ayant un diamètre non supérieur à 100 mm et non inférieur à 10 mm dans une direction de laminage à froid et pas supérieur à 50 mm et pas inférieur à 5 mm dans une direction perpendiculaire à la direction de laminage à froid et dans laquelle en outre, parmi les grains dans ladite matrice, pas moins de 50 pour cent sont des grains de recristallisation secondaire fins ayant un diamètre moyen non supérieur à 5 mm, dans laquelle le bismuth et l'aluminium soluble dans un acide sont contenus en tant que composants inhibiteurs.
  2. Tôle d'acier électrique à grains orientés à très haute densité de flux magnétique selon la revendication 1,
    dans laquelle, parmi les grains de recristallisation secondaire de matrice, pas moins de 90 pour cent sont constitués de grains dont les axes (110) [001] sont inclinés, par rapport à la surface laminée, de moins de 5 degrés autour soit de l'axe TD, soit de l'axe ND, et pas moins de 90 pour cent sont constitués de grains de recristallisation secondaire fins dont les axes (110) [001] sont inclinés, par rapport à la surface laminée, de moins de 10 degrés autour soit de l'axe TD, soit de l'axe ND.
  3. Tôle d'acier électrique à grains orientés à très haute densité de flux magnétique produite à partir d'une brame comprenant, en poids, de 0,03 à 0,15 pour cent de carbone, de 2,5 à 4,0 pour cent de silicium, de 0,10 à 0,80 pour cent de manganèse, jusqu'à 0,010 pour cent de soufre, de 0,010 à 0,065 pour cent d'aluminium soluble dans un acide, 0,0030 à 0,0150 pour cent d'azote, de 0,0005 à 0,05 pour cent de bismuth, optionnellement de 0,05 à 0,50 pour cent d'étain et/ou de 0,01 à 0,10 pour cent de cuivre et le reste du fer et des impuretés inévitables, et ayant une très haute densité de flux magnétique B8 non inférieure à 1,92 tesla dans laquelle, pas moins de 80 pour cent en superficie sont constitués de grains de recristallisation secondaire de matrice ayant un diamètre non supérieur à 100 mm et non inférieur à 10 mm dans une direction de laminage à froid et pas supérieur à 50 mm et pas inférieur à 5 mm dans une direction perpendiculaire à la direction de laminage à froid et dans laquelle en outre, parmi les grains dans ladite matrice, pas moins de 50 pour cent sont des grains de recristallisation secondaire fins ayant un diamètre moyen non supérieur à 5 mm, dans laquelle le bismuth et l'aluminium soluble dans un acide sont contenus en tant que composants inhibiteurs.
  4. Un procédé de fabrication d'une tôle d'acier électrique à grains orientés à très haute densité de flux magnétique selon l'une quelconque des revendications 1 à 3, comprenant les étapes de coulée d'un matériau de tôle d'acier électrique à grains orientés à très haute densité de flux magnétique pour former une brame d'acier, chauffage de la brame, laminage à chaud de la brame, si nécessaire exécution d'un recuit à haute température avant laminage à froid final et refroidissement de l'acier, laminage à froid de l'acier en une seule étape, ou en deux étapes ou plus avec un recuit intermédiaire entre elles incluant un laminage à froid final à un taux de réduction de 65 à 95 pour cent, recuit de décarburation et application d'un séparateur de recuit, et recuit de finition de recristallisation secondaire, dans lequel du bismuth ou un composé contenant du bismuth est ajouté à l'acier fondu en quantité équivalente de bismuth de 100 à 5000 g/tonne d'acier fondu, grâce à quoi le bismuth et l'aluminium soluble dans un acide résultent en des composants inhibiteurs.
  5. Un procédé de fabrication d'une tôle d'acier électrique à grains orientés à très haute densité de flux magnétique selon la revendication 4,
    dans laquelle la brame contient, en poids, de 0,02 à 0,30 pour cent de manganèse, de 0,005 à 0,040 pour cent de soufre et la brame est chauffée à au moins 1.280 °C.
  6. Un procédé de fabrication d'une tôle d'acier électrique à grains orientés à très haute densité de flux magnétique selon la revendication 4,
    dans laquelle la brame contient, en poids, de 0,10 à 0,80 pour cent de manganèse, jusqu'à 0,010 pour cent de soufre, la brame est chauffée à pas plus de 1.270 °C et le recuit de décarburation est suivi par un traitement de nitruration.
  7. Un procédé de fabrication d'une tôle d'acier électrique à grains orientés à très haute densité magnétique selon l'une quelconque des revendications 4 à 6,
    comprenant l'obtention d'une épaisseur de produit de 0,23 mm à 0,15 mm par un laminage à froid de réduction lourde en une étape.
  8. Un procédé de fabrication d'une tôle d'acier électrique à grains orientés à très haute densité magnétique selon l'une quelconque des revendications 4 à 7,
    comprenant un laminage à froid tandem.
  9. Un procédé de fabrication d'une tôle d'acier électrique à grains orientés à très haute densité magnétique selon l'une quelconque des revendications 4 à 8,
    comprenant un recuit à haute température à 850°C à 1100°C pendant, entre 30 secondes et 30 minutes, avant le laminage à froid final.
  10. Un procédé de fabrication d'une tôle d'acier électrique à grains orientés à très haute densité magnétique selon l'une quelconque des revendications 4 à 9,
    comprenant un recuit à haute température suivant par refroidissement de pas plus de 950°C à 400°C à une vitesse qui est inférieure à 30°C/s, avant le laminage à froid final.
EP93114924A 1992-09-17 1993-09-16 Tôle d'acier électrique à grains orientés et matériau à haute densité de flux magnétique et procédé pour leur fabrication Expired - Lifetime EP0588342B1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP248194/92 1992-09-17
JP24819492 1992-09-17
JP04248194A JP3098628B2 (ja) 1992-09-17 1992-09-17 超高磁束密度一方向性電磁鋼板
JP28648692 1992-10-23
JP286486/92 1992-10-23
JP28648692A JP3324044B2 (ja) 1992-10-23 1992-10-23 超高磁束密度一方向性電磁鋼板の製造方法

Publications (2)

Publication Number Publication Date
EP0588342A1 EP0588342A1 (fr) 1994-03-23
EP0588342B1 true EP0588342B1 (fr) 2000-07-12

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EP (1) EP0588342B1 (fr)
KR (1) KR0183408B1 (fr)
DE (1) DE69328998T2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3594373A4 (fr) * 2017-05-12 2020-02-26 JFE Steel Corporation Tôle d'acier magnétique orientée et son procédé de fabrication

Families Citing this family (10)

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Publication number Priority date Publication date Assignee Title
JP3598590B2 (ja) * 1994-12-05 2004-12-08 Ｊｆｅスチール株式会社 磁束密度が高くかつ鉄損の低い一方向性電磁鋼板
JP3470475B2 (ja) * 1995-11-27 2003-11-25 Ｊｆｅスチール株式会社 極めて鉄損の低い方向性電磁鋼板とその製造方法
DE69810852T2 (de) * 1997-07-17 2003-06-05 Kawasaki Steel Corp., Kobe Kornorientiertes Elektrostahlblech mit ausgezeichneten magnetischen Eigenschaften und dessen Herstellungsverfahren
KR100538595B1 (ko) * 1997-07-17 2006-03-22 제이에프이 스틸 가부시키가이샤 자기특성이우수한방향성전자강판및그의제조방법
KR19990088437A (ko) * 1998-05-21 1999-12-27 에모또 간지 철손이매우낮은고자속밀도방향성전자강판및그제조방법
CN1321215C (zh) 2001-07-16 2007-06-13 新日本制铁株式会社 高磁场铁损和涂层特性优异的超高磁通密度单取向电工钢板及其制造方法
DE20302583U1 (de) * 2003-01-18 2003-06-12 W.E.T. Wasser-Energie-Technologie GmbH, 95359 Kasendorf Filtermembranrückspülung mit einem Druckbehälter
KR101351957B1 (ko) * 2011-11-22 2014-01-22 주식회사 포스코 자성이 우수한 방향성 전기강판 및 이의 제조방법
CN103834856B (zh) * 2012-11-26 2016-06-29 宝山钢铁股份有限公司 取向硅钢及其制造方法
KR102504894B1 (ko) * 2019-01-31 2023-02-28 제이에프이 스틸 가부시키가이샤 방향성 전기 강판 및 그것을 사용한 철심

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Publication number Priority date Publication date Assignee Title
EP0101321B1 (fr) * 1982-08-18 1990-12-05 Kawasaki Steel Corporation Procédé pour la production de tôle ou de bande en acier au silicium à grain orienté présentant une haute induction magnétique et faible perte dans le fer
CA1229542A (fr) * 1984-05-24 1987-11-24 Yoshiaki Iida Production de tole d'acier au silicium a grains orientes
JPH0713266B2 (ja) * 1987-11-10 1995-02-15 新日本製鐵株式会社 鉄損の優れた薄手高磁束密度一方向性電磁鋼板の製造方法
JPH0230740A (ja) * 1988-04-23 1990-02-01 Nippon Steel Corp 鉄損の著しく優れた高磁束密度一方向性電磁鋼板及びその製造方法
EP0390142B2 (fr) * 1989-03-30 1999-04-28 Nippon Steel Corporation Procédé de fabrication d'une tÔle en acier électromagnétique à grain orienté ayant une haute densité de flux magnétique
JPH0717960B2 (ja) * 1989-03-31 1995-03-01 新日本製鐵株式会社 磁気特性の優れた一方向性電磁鋼板の製造方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3594373A4 (fr) * 2017-05-12 2020-02-26 JFE Steel Corporation Tôle d'acier magnétique orientée et son procédé de fabrication

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KR940007195A (ko) 1994-04-26
EP0588342A1 (fr) 1994-03-23
KR0183408B1 (ko) 1999-04-01
DE69328998D1 (de) 2000-08-17
DE69328998T2 (de) 2001-03-01

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