EP0143548B1 - Kornorientiertes Siliziumstahlblech mit geringem Eisenverlust, nicht verschlechtert durch Spannungsfreiglühen, und Verfahren zu dessen Herstellung - Google Patents

Kornorientiertes Siliziumstahlblech mit geringem Eisenverlust, nicht verschlechtert durch Spannungsfreiglühen, und Verfahren zu dessen Herstellung Download PDF

Info

Publication number
EP0143548B1
EP0143548B1 EP84307320A EP84307320A EP0143548B1 EP 0143548 B1 EP0143548 B1 EP 0143548B1 EP 84307320 A EP84307320 A EP 84307320A EP 84307320 A EP84307320 A EP 84307320A EP 0143548 B1 EP0143548 B1 EP 0143548B1
Authority
EP
European Patent Office
Prior art keywords
steel sheet
regions
annealing
film
forsterite film
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP84307320A
Other languages
English (en)
French (fr)
Other versions
EP0143548A1 (de
Inventor
Ujihiro C/O Research Laboratories Nishiike
Michiro C/O Research Laboratories Komatsubara
Yoshiaki C/O Research Laboratories Iida
Isao C/O Research Laboratories Matoba
Yukio C/O Research Laboratories Inokuti
Yo C/O Research Laboratories Ito
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Steel Corp
Original Assignee
Kawasaki Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=27327923&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0143548(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Priority claimed from JP58201279A external-priority patent/JPS6092479A/ja
Priority claimed from JP58201281A external-priority patent/JPS6092481A/ja
Priority claimed from JP58201280A external-priority patent/JPS6092480A/ja
Application filed by Kawasaki Steel Corp filed Critical Kawasaki Steel Corp
Publication of EP0143548A1 publication Critical patent/EP0143548A1/de
Application granted granted Critical
Publication of EP0143548B1 publication Critical patent/EP0143548B1/de
Expired legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01F1/14783—Fe-Si based alloys in the form of sheets with 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
    • 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
    • C21D8/1294—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a localized treatment
    • 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 a grain-oriented silicon steel sheet having a low iron loss, and a method of producing the steel sheet, and more particularly relates to a technique for lowering the iron loss of a grain-oriented silicon steel sheet by giving non-uniformity to a coating film formed on the steel sheet surface so as to define and form, on the steel sheet surface, local regions which are subjected to a tensile force different from that acting upon the remaining regions of the steel sheet surface.
  • Grain-oriented silicon steel sheets are mainly used in the iron cores of transformers and other electric instruments, and are required to have excellent magnetic properties and particularly to have a low iron loss represented by W 17/50 .
  • Japanese Patent Application Publication No. 23,647/79 discloses a method wherein secondary recrystallization-checking regions are formed on the steel sheet surface whereby finely divided secondary recrystallization grains are produced.
  • this technique cannot reliably control the size of the secondary recrystallization grain, and is not a practical method.
  • Japanese Patent Application Publication No. 5,968/83 disclose a technique wherein slight strain is introduced into the surface of the secondary recrystallized steel sheet by means of a ball-point pen-like small globe to subdivide the magnetic domain wall spacing whereby the iron loss is lowered.
  • Japanese Patent Application Publication No. 2,252/82 discloses a technique wherein laser beams are irradiated on to the surface of the final steel sheet product at intervals of several mm in a direction substantially perpendicular to the rolling direction to introduce high dislocation density regions into the surface layer of the steel sheet whereby the magnetic domain wall spacing is subdivided to lower the iron loss.
  • 188,810/82 discloses a technique wherein slight strain is introduced into a steel sheet surface layer by means of an electric spark whereby the magnetic domain wall spacing is subdivided to lower the iron loss.
  • slight plastic strain is introduced into the surface layer of the secondarily recrystallized steel sheet matrix, whereby the magnetic domain wall spacing is subdivided to lower the iron loss, and these methods are practical methods, and are excellent for lowering the iron loss.
  • the effect attained by the introduction of plastic strain into the steel sheet is lost by heat treatments, such as stress-relief annealing and the baking treatment of coating, which are carried out after punching, shearing, coiling and the like of the steel sheet.
  • Japanese Patent Application Publication No. 17,757/78 discloses a technique for lowering magnetostriction of a grain-oriented silicon steel sheet by forming inorganic coating films having a stripe-shaped pattern or checkered pattern on both matrix surfaces of the steel sheet.
  • the object of the present invention is to provide a grain-oriented silicon steel sheet having excellent magnetic properties by subdividing the magnetic domain wall spacing based on a technical idea different from that of the above described prior art, which steel sheet retains its excellent magnetic properties, obtained by the subdivision of the magnetic domain wall spacing, even after stress-relief annealing at high temperatures.
  • EP-A-0 033 878 discloses that grain-oriented silicon treated sheets for transformers and the like are known wherein the surface of the sheets are coated with forsterite which is overcoated with an insulating film based on, for example, a phosphate.
  • a grain-oriented silicon steel sheet comprising a matrix surface layer coated with a forsterite film characterised in that the matrix surface layer is free of plastically strained zones and includes regions of first and second types wherein the first type is coated with forsterite film and the second type is free of forsterite film or carries forsterite film having a thickness which is different to the thickness of the forsterite film carried by the first type, the grain oriented sheet having a low iron loss which is free from deterioration due to stress-relief annealing.
  • the present invention is based on the discoveries that, when a grain-oriented silicon steel sheet has local regions coated with different thicknesses of forsterite film the magnetic domain wall spacing can be very advantageously subdivided in the resulting grain-oriented silicon steel sheet because there occurs local non-uniformity of magnetic field or elastic strain field; and that, when a tension-giving type insulating coating is applied onto a grain-oriented silicon steel sheet having such regions the subdividing of the magnetic domain width can be more improved as a result of their synergistic effect.
  • steel sheets which include forsterite films of different thicknesses in the first and second types of regions are referred to as having "forsterite film different-thickness regions", or merely “different-thickness regions”.
  • the present invention is further based on the discoveries that, when a grain-oriented silicon steel sheet has local regions which are coated with forsterite film and local regions which are free of forsterite film, the magnetic domain width of the resulting grain-oriented silicon steel sheet can be very advantageously subdivided similarly to the case where the sheet includes forsterite film different-thickness regions; and that, when a tension-giving type insulating coating is applied onto a grain oriented sheet having such regions the subdividing of the magnetic domain width can be more improved as a result of their synergistic effect.
  • steel sheets which include regions of a first type coated with forsterite film and regions of a second type which are free of forsterite film are referred to as having "non-forsterite film regions" or merely “filmless regions”.
  • a cold rolled steel sheet having a final gauge is generally subjected to a decarburization annealing to remove harmful carbon.
  • the decarburized steel sheet has a primary recrystallization texture containing an inhibitor, which forms a fine second phase dispersed in the interior of the steel sheet, and at the same time the surface layer of the steel sheet has a subscale structure consisting of the matrix and fine Si0 2 grains dispersed in the matrix.
  • the steel sheet After the decarburized and primary recrystallized sheet has an annealing separator consisting mainly of MgO applied to its surface, the steel sheet is subjected to a secondary recrystallization and purification annealing (a final annealing) at a high temperature of about 1,200°C.
  • a secondary recrystallization and purification annealing a final annealing
  • the crystal grains in the steel sheet grow into coarse grains having a ⁇ 100 ⁇ 001> orientation.
  • a part of the inhibitors, such as S, Se, N, etc. which remains in the steel sheet, is removed from the steel sheet matrix.
  • Si0 2 in the subscale of the surface layer of the steel sheet and MgO in the annealing separator coated on the steel surface react with each other according to the following equation: to form a coating film consisting of a polycrystal of forsterite (Mg 2 Si0 4 ) on the surface layer of the steel sheet.
  • Mg 2 Si0 4 polycrystal of forsterite
  • unreacted excess MgO serves to prevent fusing between adjacent steel sheets.
  • the unreacted annealing separator is removed from the steel sheet, and if necessary, an insulating coating is finally applied or a coil set is removed to obtain a product steel sheet.
  • the inventors have reinvestigated the role of forsterite film, and have found that the film gives a tensile force to the steel sheet to subdivide the magnetic domain wall spacing and the subdivision effect of the magnetic domain wall spacing in the steel sheet varies. As a result, the inventors have reexamined carefully the subdivision effect of the magnetic domain wall spacing in a steel sheet, and have found that the above mentioned effect is remarkable in places where the tensile stress field or the magnetic field is changed by the thickness of the foresterite film.
  • the grain-oriented silicon steel sheet has a low iron loss free from deterioration due to the stress-relief annealing, no plastically strained zones in the matrix surface layer, and a forsterite film coated on the surface wherein first regions of the surface have a forsterite film having a thickness different from that of the forsterite film in second regions of the surface.
  • the grain-oriented silicon steel sheet has a low iron loss free from deterioration due to the stress-relief annealing, no plastically strained zones in the matrix surface layer, and a forsterite film coated on the surface wherein first regions of the surface have a forsterite film having a thickness different from that of the forsterite film in second regions of the surface, said steel sheet further having a tension-giving type insulating coating film having a thermal expansion coefficient of not higher than 9.8x10- 6 1/°C formed on the forsterite film.
  • the grain-oriented silicon steel sheet has a low iron loss free from deterioration due to the stress-relief annealing, no plastically strained zones in the matrix surface layer, and a discontinuous forsterite film coated on the surface whereby first regions of the surface have no forsterite film coating and second regions of the surface do have a forsterite film coating.
  • the grain-oriented silicon steel sheet has a low iron loss free from deterioration due to the stress-relief annealing, no plastically strained zones in the matrix surface layer, and a discontinuous forsterite film coated on the surface whereby first regions of the surface have no forsterite film coating and second regions of the surfaces do have a forsterite film coating said steel sheet further having a tension-giving type insulating coating having a thermal expansion coefficient of not higher than 9.8x 10- 6 1/°C formed on the forsterite film.
  • the present invention also provides a method of producing a grain oriented silicon steel sheet as claimed in claim 6.
  • the starting material steel sheets are limited to ones having no plastically strained zones.
  • the reason is that the subdivision of the magnetic domain wall spacing by the introduction of a plastic strain into the steel sheet causes a serious deterioration in the properties due to the stress-relief annealing as described later.
  • the steel sheets having a forsterite film in accordance with the present invention include not only steel sheets having a forsterite film alone but also steel sheets having a general top coating film formed on the forsterite film as a surface coating.
  • the inventors have changed locally the thickness of a forsterite film on the sheet surface or have removed locally forsterite film from the sheet surface to provide the sheet surface with different regions and have investigated the influence of the shape, thickness difference, direction, etc. of these regions, upon the subdivision of the magnetic domain wall spacing, and have studied the relationship between the shape, thickness difference, direction, etc. of the regions upon the iron loss of the product steel sheet.
  • a continuous or discontinuous linear groove or land as illustrated in Fig. 1A is especially effective for lowering the iron loss.
  • a discontinuous linear groove or land formed of recesses or protrusions arranged in a row when the distance between adjacent recesses or protrusions is more than 0.5 mm, the effect is low.
  • the effect for lowering the iron loss is almost the same as that of a continuous linear groove or land.
  • Figs. 1B and 2 Regarding the direction of the different-thickness regions, as illustrated in Figs. 1B and 2, it is especially effective in the case of an inclination angle of 60 ⁇ 90° with respect to the rolling direction (measuring condition in Fig. 2: sheet thickness: 0.30 mm; dotted line-like different-thickness region, interval: 4 mm, width: 1 mm, decreased thickness: 1.5 mm). Further, regarding the thickness difference between the regions, as illustrated in Fig. 3, both the larger thickness region and the smaller thickness region exhibit almost the same effect. In any case, it has been found that it is effective when the thickness difference is not less than 0.3 um (measuring condition in Fig.
  • the interval between adjacent regions as illustrated in Fig. 1C is desirably within the range of 1-30 mm as illustrated Fig. 5 (measuring condition in Fig. 5: sheet thickness: 0.30 mm; linear groove, angle; 90°, width: 1 mm, thickness difference: 0.5 pm).
  • the effect of the different-thickness regions is almost the same when the regions are provided on both surfaces of the steel sheet and when the regions are provided only on one surface thereof.
  • the coating film located around the removed portion of the coating film is flowed into the removed portion of the coating film by the stress-relief annealing so as to repair the removed portion of the coating film into a uniform surface, and the coating film has excellent insulating property and corrosion resistance. It has been found that the annealing temperature necessary for repairing such coating film is preferably within the range of 600-900°C.
  • a continuous or discontinuous linear region free of forsterite as illustrated in Fig. 1A is especially effective for lowering the iron loss.
  • a discontinuous linear filmless region formed of recesses arranged in a row when the distance between adjacent recesses is more than 0.5 mm, the effect is low.
  • the effect for lowering the iron loss is almost the same as that of a continuous linear filmless region.
  • Figs. 1 B and 7 Regarding the direction of the filmless region, as illustrated in Figs. 1 B and 7, it is especially effective in the case of an inclination angle of 60-90° with respect to the rolling direction (measuring condition in Fig. 7: sheet thickness: 0.30 mm; dotted line-like filmless region, interval: 4 mm, width: 1 mm).
  • Fig. 8 Regarding the width of the continuous or discontinuous linear filmless region, an excellent effect is obtained within the range of 0.05-2.0 mm, preferably 0.8-1.5 mm, as illustrated Fig. 8 (measuring condition in Fig. 8: sheet thickness: 0.30 mm; linear filmless region, interval: 3 mm, angle: 90°).
  • the distance between adjacent filmless regions as illustrated in Fig. 1C is desirably within the range of 1-30 mm as illustrated Fig. 9 (measuring condition in Fig. 9: sheet thickness: 0.30 mm; linearfilmless region, angle: 90°, width: 1 mm).
  • the effect of the filmless regions is almost the same in the case where a forsterite film having regions free of forsterite is formed on each surface of a steel sheet and in the case where a forsterite film having regions free of forsterite is formed only on one surface thereof.
  • a finally annealed silicon steel sheet having a forsterite film on the matrix surface and further having a tension-giving type coating film having a thermal expansion coefficient of 5.6x10-6 1/°C formed on the forsterite film was divided into 4 steel sheets, and regions free of forsterite film, each having a width of 1.0 mm, were formed at an inclination angle of 90° with respect to the rolling direction and at a repeating interval of 4 mm by the following methods.
  • any of the above described methods (1)­(4) resulted in grain-oriented silicon steel sheets having a very low iron loss of W 17/50 of 0.97-0.98 W/kg.
  • the steel sheets treated with methods (1), (2) and (4) still had a low iron loss of 0.97-0.98 W/kg, but the iron loss of the steel sheet treated with method (3) was noticeably deteriorated to 1.05 W/kg.
  • the inventors have ascertained the reason as follows.
  • the steel sheets treated with methods (1)­(4) before the stress-relief annealing only the steel sheet treated with method (3) had a plastically strained zone formed in the matrix surface layer just beneath the region, wherein the forsterite film has been removed, and this plastic strain is released and extinguished by the stress-relief annealing. Accordingly, in order not to deteriorate the iron loss due to the stress-relief annealing, it is important that plastically strained zones are not introduced into the steel sheet matrix surface layer.
  • the coating film located around the removed portion of the coating film is flowed into the removed portion of the coating film by the stress-relief annealing so as to repair the removed portion of the coating film into a uniform surface, and the coating film has excellent insulating property and corrosion resistance. It has been found that the annealing temperature necessary for repairing such coating film is preferably within the range of 600-900°C.
  • a hot rolled coil produced by a method, wherein a molten steel is produced by a commonly known steel-making process, for example, by a converter, an electric furnace, etc., the molten steel is subjected to an ingot making-slabbing process or a continuous casting process etc. to produce a slab, and the slab is subjected to a hot rolling.
  • the hot rolled sheet has a composition containing about 2.0-4.0% by weight of Si.
  • a Si content of less than 2.0% results in a grain-oriented silicon steel sheet having a very poor iron loss, and a Si content of more than 4.0% results in a poor cold workability of the hot rolled sheet.
  • any constituents for grain-oriented silicon steel sheets are applicable.
  • the hot rolled sheet is subjected to one cold rolling or two or more cold rollings with an intermediate annealing between them to produce a cold rolled sheet having a final gauge.
  • a normalizing annealing of the hot rolled sheet or a warm annealing instead of the cold rolling may be carried out.
  • the cold rolled sheet having a final gauge is subjected to a primary recrystallization annealing under an oxidizing atmosphere capable of decarburization or under a weak oxidizing atmosphere capable of forming a subscale. Then, an annealing separator consisting mainly of MgO is applied to the steel sheet surface. In this application step, regions not coated with annealing separator are locally formed on the steel sheet surface, whereby the object aimed in the present invention are advantageously achieved.
  • an ordinary forsterite film is formed on the surface coated with the annealing separator.
  • a thin forsterite film is formed on the surface which was not coated with the annealing separator, so that the sheet surface is provided with different thickness-regions as required by the first and second embodiments of the present invention.
  • the inhibitor there can be used oxides such as Si0 2 , AI z 0 3 , Zr0 2 , etc. and metals such as Zn AI, Sn, Ni, Fe, etc.
  • oxides such as Si0 2 , AI z 0 3 , Zr0 2 , etc.
  • metals such as Zn AI, Sn, Ni, Fe, etc.
  • water-repelling substances oil paint and varnish, etc. are advantageously used.
  • the water-repelling substances prevent contact of the steel sheet surface with the annealing separator to delay the forsterite forming reaction and to form a region of smaller thickness.
  • the reaction-delaying effect becomes excessive, and a forsterite film is not at all formed. Therefore, it is necessary that the degree to which the thickness of the forsterite film is to be decreased is controlled by using the water-repelling substance in an amount persistently of not more than 0.1 g/m 2 .
  • the oxidizing agent oxidizes Si in the steel at a high temperature during the following final annealing to increase the amount of Si0 2 particles in the subscale of the steel sheet surface layer and to increase the thickness of the forsterite film after the final annealing. Hence, a larger thickness film can be locally formed on the steel sheet surface.
  • oxides such as FeO, Fe 2 0 3 , TiO z , etc.
  • easily reducible silicates such as Fe 2 Si0 4 , etc. hydroxides, such as Mg(OH) 2 , etc.
  • the method besides chemical polishing and electrolytic polishing, there are methods of removing the forsterite film by using a rotating disc-like grindstone, by using an iron needle under a light pressure, and by optical means, for example laser beams, etc. having their power properly adjusted, and other methods.
  • optical means for example laser beams, etc. having their power properly adjusted, and other methods.
  • laser beams when laser beams are used as the optically removing method, multiple beams may be taken out from one light source or the whole irradiation may be effected in the presence of an appropriate mask, whereby a plural number of different-thickness regions can be advantageously formed efficiently by one operation.
  • a continuous linear groove or land is especially effective.
  • the continuous linear groove or land can be replaced by a discontinuous linear groove or land, that is, by recesses or protrusions arranged in a row.
  • a discontinuous linear groove or land when the distance between adjacent recesses or protrusions is more than 0.5 mm, the effect is low. Further, when the width of the linear different-thickness region or linear filmless region is about 0.05-2.0 mm, the effect is high.
  • an inclination angle within the range of 60-90° with respect to the rolling direction is especially preferable.
  • the inclination angle with respect to the rolling direction of the steel sheet is especially important. The reason why the effect for lowering the iron loss is poor in the case of excessively large width of the different-thickness region or filmless region, or in the case of isolated recesses or protrusions, is probably because the directional effect of the whole regions does not sharply appear.
  • the continuous or discontinuous linear groove or land is arranged repeatedly with respect to the rolling direction.
  • the interval between adjacent grooves or lands is within the range of 1.0-30 mm.
  • the continuous or discontinuous linear groove or land may have different shapes and widths, and may be arranged in different angles with respect to the rolling direction.
  • the effect of providing the different-thickness regions or the filmless regions is almost the same in the case where the regions are present on both surfaces of the steel sheet as in the case where the regions are present only on one surface of the steel sheet.
  • silicon steel sheets having more excellent magnetic properties can be produced in the following manner.
  • a tension-giving type insulating coating film having a thermal expansion coefficient of not more than 9.8x10- 6 1/°C is formed as a top coating on a grain-oriented silicon steel sheet having a forsterite film, and then the top coating and a part of the forsterite film or the top coating and all of the forsterite film are locally removed to form regions including a small thickness of forsterite film or regions which are free of forsterite film and then.the steel sheet is subjected to an annealing at a temperature of 600-900°C to repair the portions where the top coating is absent.
  • the top coating gives a surface tension to the steel sheet surface by the difference in thermal expansion coefficient between the steel sheet and the coating film, and therefore it is necessary that the top coating film has a thermal expansion coefficient somewhat different from that of the steel sheet.
  • the inventors have ascertained that a top coating film having a thermal expansion coefficient of not higher than 9.8x 10- 6 1/°C gives a satisfactorily low iron loss value to the product steel sheet by the synergistic effect of the effect caused by the different-thickness regions or fil mless regions and the surface tension-giving effect of the top coating film.
  • the thickness of the coating film is preferably within the range of about 0.5-10 g/m 2 (per one surface) in view of corrosion resistance and space factor.
  • the grain-oriented silicon steel sheets having different-thickness regions or filmless regions exhibit excellent magnetic properties in both cases.
  • the steel sheets can be directly used in a practical apparatus similar to the commonly used grain-oriented silicon steel sheets or they can be used in a practical apparatus after they have been provided with the top insulation coating.
  • the iron loss value is lowered by defining and forming different-thickness regions or filmless regions in the forsterite film. The reason is probably that these regions are subjected to different tensions and plastic strain is introduced into the steel sheet surface by the action of these different tensions so that the magnetic domain wall spacing is effectively subdivided.
  • a cold rolled steel sheet of 0.30 mm in thickness was prepared from a hot rolled silicon steel sheet containing 3.2% of Si according to the ordinary method, and subjected to a decarburization-primary recrystallization annealing. Then, before an annealing separator was applied to the surface of the annealed sheet, A1 2 0 3 powder as an inhibitor for the forsterite forming reaction was adhered linearly to the steel sheet surface under the following conditions:- adhesion amount: 0.5 g/m 2 , the inclination angle with respect to the rolling direction: 90°, the adhesion width: 2 mm, and the repeating interval in the rolling direction: 4 mm. Thereafter, the annealing separator was applied onto the thus treated steel sheet, and then the steel sheet was subjected to a final annealing at 1,200°C for 5 hours.
  • a grain-oriented silicon steel sheet was prepared as a Comparative Example according to the ordinary method wherein A1 2 0 3 powder was not adhered.
  • the above top coated steel sheets were subjected to a stress-relief annealing at 800° for 2 hours, and the iron loss values of the annealed sheets were measured.
  • the obtained values are as follows.
  • a cold rolled steel sheet of 0.28 mm in thickness was prepared from a hot rolled silicon steel sheet containing 3.0% of Si according to the ordinary method, and subjected to a decarburization-primary recrystallization annealing.
  • an annealing separator consisting mainly of MgO was once applied onto the surface of the annealed steel sheet, the annealing separator was removed linearly by a plastic bar with a fine tip under the following conditions: ⁇ the inclination angle with respect to the rolling direction: 90°, the width: 0.5 mm, and the repeating interval in the rolling direction: 2 mm.
  • the steel sheet was subjected to a final annealing at 1,200°C for 5 hours.
  • Example 2 Examination of the film properties of both the samples showed, that, in the Comparative Example, a grey forsterite film of a uniform thickness was formed, while in Example 2, a forsterite film having a small thickness was formed at the regions at which the annealing separator was removed.
  • the iron loss values of Example 2 and the Comparative Example were as follows:
  • a cold rolled steel sheet of 0.23 mm in thickness was prepared from a hot rolled silicon steel sheet containing 3.0% of Si according to the ordinary method, and subjected to a decarburization . primary recrystallization.annealing. After an annealing separator consisting mainly of MgO was once applied onto the surface of the annealed steel sheet, the annealing separator was removed linearly by a plastic bar with a fine tip under the following ⁇ onditions:­the inclination angle with respect to the rolling direction: 90°, the width: 0.5 mm, and the repeating interval in the rolling direction: 5 mm. Then, the steel sheet was subjected to a final annealing at 1,200°C for 5 hours. A steel sheet treated up to the final annealing step according to the ordinary steps, wherein the annealing separator was not removed was adopted as a Comparative Example.
  • Example 3 Examination of the film properties of both the samples showed that, in the Comparative Example, a grey forsterite film of a uniform thickness was formed; while in Example 3, a forsterite film having a small thickness was formed at the regions at which the annealing separator was removed.
  • the iron loss values of Example 3 and the Comparative Example were as follows:
  • a cold rolled steel sheet of 0.30 mm in thickness was prepared from a hot rolled silicon steel sheet containing 3.0% of Si according to the ordinary method, and subjected to a decarburization - primary recrystallization annealing. Then, an annealing separator was applied to the surface of the steel sheet by means of a rubber roll with ridges. At this time, the annealing separator was applied to the steel sheet surface such that applied regions and non-applied regions were alternatively defined and formed with respect to the rolling direction under the following conditions:- the width of the non-applied region: 1.5 mm, and the repeating interval in the rolling direction: 5 mm. Thereafter, the steel sheet was subjected to a final annealing at 1,200°C for 5 hours. For comparison, a grain-oriented silicon steel sheet as a Comparative Example was prepared according to the ordinary production steps in which the forsterite film was uniformly formed over the whole surface of the steel sheet.
  • a cold rolled steel sheet of 0.30 mm in thickness was prepared from a hot rolled silicon steel sheet containing 3.2% of Si according to the ordinary method, and subjected to a decarburization - primary recrystallization annealing. Then, prior to the application of an annealing separator, FeO as an oxidizing agent for Si contained in the steel was linearly applied to the surface of the steel sheet under the following conditions:- the amount of FeO: 0.5 g/m 2 , the inclination angle with respect to the rolling direction: 90°, the width: 2 mm, and the repeating interval in the rolling direction: 10 mm.
  • a grain-oriented silicon steel sheet was prepared as a Comparative Example according to the ordinary steps in which no oxidizing agent was applied prior to the application of the annealing separator.
  • the iron loss values were as follows:
  • a cold rolled steel sheet of 0.20 mm in thickness was prepared from a hot rolled silicon steel sheet containing 3.2% of Si according to the ordinary method, and subjected to a decarburization - primary recrystallization annealing. Then prior to the application of an annealing separator, the surface of the steel sheet was printed with an oil paint having water-repellent property to the annealing separator slurry in an amount of 0.05 g/m 2 by a printing process in the form of a discontinuous straight line under the following ⁇ onditions:­ the inclination angle of the printed regions with respect to the rolling direction: 90°, the width: 0.3 mm, the distance between adjacent spots arranged in a row: 0.3 mm, and the interval of the adjacent printed regions in the rolling direction: 3 mm.
  • a grain-oriented silicon steel sheet was prepared as a Comparative Example according to the ordinary steps in which the above mentioned printing treatment of the water-repelling substance was not performed.
  • a cold rolled steel sheet of 0.30 mm in thickness was prepared from a hot rolled silicon steel sheet containing 3.2% of Si according to the ordinary method, and subjected to a decarburization - primary recrystallization annealing. Then, an annealing separator consisting mainly of MgO was applied onto the surface of the steel sheet, and the applied steel sheet was subjected to a final annealing at 1,200°C for 5 hours to form a grain-oriented silicon steel sheet with a grey forsterite film on the surface thereof.
  • the iron loss value of this steel sheet was 1.06 W/kg at W 17/50 .
  • the iron loss of the steel sheet thus obtained was 1.02 W/kg at W 17/50 .
  • the iron loss value after a stress-relief annealing of the above obtained steel sheet at 850°C for 2 hours was 1.01 W/kg at W 17/50 .
  • a cold rolled steel sheet of 0.30 mm in thickness was prepared from a hot rolled silicon steel sheet containing 3.2% of Si according to the ordinary method, and subjected to a decarburization - primary recrystallization annealing.
  • the resulting steel sheet was divided into two pieces, and one of them as such was coated with an annealing separator consisting mainly of MgO, and then subjected to a final annealing at 1,200°C for 5 hours, which was used as a Comparative Example.
  • the other steel sheet piece was adhered linearly on its surface with Al 2 O 3 powder as an inhibitor for the forsterite forming reaction under the following conditions:- the adhesion amount: 0.5 g/m 2 , the inclination angle with respect to the rolling direction: 90°, the adhesion width: 2 mm, and the repeating interval in the rolling direction: 4 mm, and then the annealing separator was applied thereon, followed by a final annealing.
  • each of coating liquids I-VII shown in Table 1 was applied and baked onto each of the above steel sheets to form a top coat insulating film thereon.
  • the iron loss values of the thus obtained products are shown in Table 2.
  • a grain-oriented silicon steel sheet containing 2.8% of Si and having a thickness of 0.28 mm, having an iron loss value of 1.08 W/kg at W 17/50 and having a uniform forsterite film on the surface thereof was divided into three pieces A, B and C. Then, the coating liquid II and coating liquid V shown in Table 1 were applied and baked onto the piece A and the pieces B and C respectively to produce grain-oriented silicon steel sheets each having a top coating film.
  • linear decreased thickness regions of the forsterite film were formed under the following conditions:- the width: 0.5 mm, the inclination angle with respect to the rolling direction: 90°, and the interval between adjacent regions in the rolling direction: 3 mm, without forming scratches on the steel sheet matrix surface by a method in which an iron needle with a fine tip was pushed against the steel sheet surface and moved thereon under a light pressure to remove the coating film and a part of the forsterite film.
  • a cold rolled steel sheet of 0.30 mm in thickness was prepared from a hot rolled silicon steel sheet containing 3.2% of Si according to the ordinary method, and subjected to a decarburization - primary recrystallization annealing. Then, the resulting steel sheet was divided into two pieces, and one of them as such was coated with an annealing separator consisting mainly of MgO, and then subjected to a final annealing at 1,200°C for 5 hours to prepare a Comparative Example.
  • the other steel sheet piece was adhered linearly on the surface with AI 2 0 3 powder as an inhibitor for the reaction of the annealing separator with Si0 2 contained in the subscales of the steel sheet under the following conditions:- the adhesion amount: 1.5 g/m 2 , the inclination angle with respect to the rolling direction: 90°, the adhesion width: 2 mm, and the repeating interval in the rolling direction: 4 mm, and then coated with the annealing separator, and subjected to a final annealing.
  • each of coating liquids I-VII shown in Table 1 was applied and baked onto each of the above steel sheets to form a top 'coat insulating film thereon.
  • the iron loss values of the thus obtained articles are shown in Table 3. Further, after a stress-relief annealing of the articles was performed at 800°C for 2 hours, the iron loss values thereof were measured. The obtained results are also shown in Table 3.
  • a cold rolled steel sheet of 0.30 mm in thickness was prepared from a hot rolled silicon steel sheet containing 3.2% of Si, and subjected to a decarburization primary recrystallization annealing according to the ordinary method. Then, prior to application of an annealing separator, the surface of the steel sheet was coated with Fe 2 Si0 4 as an oxidizing agent for Si contained in the steel under the following conditions:- the adhesion amount: 4 g/m 2 , the inclination angle with respect to the rolling direction: 90°, the width: 2 mm, and the repeating interval in the rolling direction: 10 mm, and further coated with the annealing separator, and subjected to a final annealing at 1,200°C for 5 hours.
  • a grain-oriented silicon steel sheet was prepared as a Comparative Example by the ordinary steps in which no oxidizing agent-adhering treatment was performed prior to the application of the annealing separator.
  • the iron loss values of the resulting steel sheets are as follows:
  • a cold rolled steel sheet of 0.30 mm in thickness was prepared from a hot rolled silicon steel sheet containing 3.2% of Si, and subjected to decarburization . primary recrystallization annealing. Then, the surface of the resulting steel sheet was coated with an annealing separator consisting mainly of MgO, and subjected to a final annealing at 1,200°C for 5 hours to obtain a grain-oriented silicon steel sheet having a uniform grey forsterite film on the surface thereof.
  • the iron loss value of this steel sheet was 1.06 W/kg at W 17/50 .
  • filmless regions were formed in the forsterite film under the following ⁇ onditions:­ the width: 0.5 mm, the inclination angle with respect to the rolling direction: 90°, and the interval between adjacent regions in the rolling direction: 6 mm, by a method, in which an iron needle with a fine tip was pushed against the steel sheet surface and moved thereon under a light pressure to draw a line and to remove the forsterite film.
  • the iron loss of the above treated steel sheet was 1.02 W/kg at W 17/50 .
  • a grain-oriented silicon steel sheet containing 2.8% of Si, having a thickness of 0.28 mm, having an iron loss value of 1.08 W/kg at W 17/50 , and having a uniform forsterite film formed on the surface thereof was divided into three pieces A, B and C. Then, the coating liquid II and the coating liquid VI shown in Table 1 were applied and baked onto the piece A and the pieces B and C respectively to produce grain-oriented silicon steel sheets each having a top coating film.
  • linear filmless regions were formed in the forsterite film under the following conditions:- the width: 0.5 mm, the inclination angle with respect to the rolling direction: 90°, and the interval between adjacent regions in the rolling direction: 5 mm, without forming scratches on the steel sheet matrix surface by a method in which an iron needle with a fine tip was pushed against the steel sheet surface and moved thereon under a light pressure to remove the coating film and forsterite film.
  • the pieces A, B and C were subjected to an annealing at 800°C for 10 minutes.
  • the filmless regions of the coating film on the surface of the piece C were repaired by such an annealing treatment.
  • the iron loss values of the thus treated steel sheets were:

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Dispersion Chemistry (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing Of Steel Electrode Plates (AREA)
  • Soft Magnetic Materials (AREA)

Claims (14)

1. Kornorientiertes Siliziumstahlblech mit einer matrixförmigen Oberflächenschicht, beschichtet mit einem Forsteritfilm, dadurch gekennzeichnet, daß die matrixförmige Oberflächenschicht frei von plastisch beanspruchten Zonen ist und Bereiche erster und zweiter Typen aufweist, von denen der erste Type mit Forsteritfilm beschichtet ist und der zweite Typ frei von Forsteritfilm ist oder Forsteritfilm mit einer Stärke trägt, die sich von der Stärke des vom ersten Type getragenen Forsteritfilms unterscheidet, wobei das kornorientierte Blech einen niedrigen Eisenverlust aufweist, der frei ist von Verschlechterung infolge von Spannungsfreimachen.
2. Stahlblech nach Anspruch 1, bei dem die Bereiche des zweiten Typs die Form kontinuierlicher oder diskontinuierlicher linearer Nuten oder Vorsprünge aufweisen.
3. Stahlblech nach Anspruch 2, bei dem die kontinuierlichen oder diskontiuieriichen linearen Nuten oder Vorsprünge in bezug auf die Walzrichtung des Stahlblechs um einen Winkel von 60-90° abgewinkelt sind.
4. Stahlblech nach Anspruch 1, 2 oder 3, bei dem die Bereiche des zweiten Typs einen Forsteritfilm mit einer Stärke tragen, die um nicht weniger als 0,3 pm von der Stärke des von den Bereichen des ersten Typs getragenen Forsteritfilms differiert.
5. Kornorientiertes Siliziumstahlblech nach einem der vorhergehenden Ansprüche, welches zusätzlich versehen ist mit einem spannungsgebenden isolierenden Beschichtungsfilm, der einen Wärmeausdehnungskoeffizienten von nicht mehr als 9,8x10-1 1/°C aufweist und auf dem Forsteritfilm gebildet ist.
6. Verfahren zum Herstellen eines kornorientierten Siliziumstahlblechs nach Anspruch 1, bei dem ein warmgewalztes Blech, das durch Warmwalzen aus einer siliziumhaltigen Stahlbramme hergestellt wurde, einem Kaltwalzvorgang oder zwei oder mehreren Kaltwalzvorgängen mit einem Zwischenglühvorgang zwischen diesen Vorgängen ausgesetzt wird, um ein kaltgewalztes Blech mit einem End-Maß herzustellen, das kaltgewalzte Blech einem zur Entkohlung vorgesehenen ersten Umkristallisationsglühvorgang ausgesetzt wird, ein hauptsächlich aus MgO bestehendes Glühtrennmittel auf die Oberfläche des entkohlten und primär umkristallisierten Stahlblechs aufgebracht wird, und das so behandelte Stahlblech einem End-Glühvorgang ausgesetzt wird, um einen Forsteritfilm auf der Stahblechoberfläche zu bilden, dadurch gekennzeichnet, daß das Blech Bereiche, die keinen Forsteritfilm tragen, oder Bereiche aufweist, die Forsteritfilme mit verschiedenen Stärken tragen.
7. Verfahren nach Anspruch 6, bei dem die Bereiche durch örtliches Aufbringen des Glühtrennmittels auf die Oberfläche des entkohlten und primär umkristallisierten Stahlblechs geschaffen werden.
8. Verfahren nach Anspruch 6, bei dem die Bereiche durch gleichförmiges Aufbringen des Glühtrennmittels auf die Oberfläche des entkohlten und primär umkristallisierten Stahlblechs und anschließendes örtliches Entfernen von Glühtrennmittel von der Stahlblechoberfläche geschaffen werden.
9. Verfahren nach Anspruch 6, bei dem die Bereiche geschaffen werden, indem man vor dem Aufbringen des Glühtrennmittels örtlich einen Inhibitor für die forsteritbildende Reaktion mit einer Menge von nicht mehr als 1 g/m2 an der Oberfläche des entkohlten und primär umkristallisierten Stahlblechs anhaften läßt.
10. Verfahren nach Anspruch 6, bei dem die Bereiche geschaffen werden, indem man örtlich eine für eine Schlempe des Glühtrennmittels wasserabstoßende Substanz mit einer Menge von nicht mehr als 0,1 g/m2 an der Oberfläche des entkohlten und primär umkristallisierten Stahlblechs anhaften läßt, bevor die Schlempe des Glühtrennmittels aufgebracht wird.
11. Verfahren nach Anspruch 6, bei dem die Bereiche geschaffen werden, indem man örtlich ein Oxidiermittel für in dem Stahl enthaltenes Si in einer Menge von nicht mehr als 2.0 g/m2 an der Oberfläche des entkohlten und primär umkristallisierten Stahlblechs anhaften läßt, bevor die Schlempe des Glühtrennmittels aufgebracht wird.
12. Verfahren nach Anspruch 6, bei dem die Bereiche durch örtliches Entfernen eines Teiles oder des gesamten während des End-Glühens gebildeten Forsteritfilms geschaffen werden, ohne eine plastische Beanspruchung im Inneren der Stahlblechmatrix zu verursachen.
13. Verfahren nach Anspruch 6, mit dem zusätzlichen Schritt, daß man auf die dne Forsteritfilm tragende Stahlblechoberfläche eine Ober-Beschichtungsflüssigkeit aufbringt, die einen spannungsgebenden isolierenden Ober-Beschichtungsfilm mit einem Wärmeausdehnungskoeffizienten von nicht mehr als 9,8x 10-6 1¡OC bildet, und man die Beschichtungsflüssigkeit in einem Temperaturbereich von 60G-900°C an den Forsteritfilm anbackt.
14. Verfahren nach Anspruch 13, bei dem der Ober-Beschichtungsfilm und mindestens ein Teil des Forsteritfilms örtlich entfernt werden, ohne eine plastische Beanspruchung im Inneren der Stahlblechmatrix zu verursachen, um das Blech mit den Bereichen zu versehen, und dann zur Wiederherstellung des Ober-Beschichtungsfilms das so behandelte Stahlblech einem Glühvorgang in einem Temperaturbereich von 60G-900°C ausgesetzt wird.
EP84307320A 1983-10-27 1984-10-24 Kornorientiertes Siliziumstahlblech mit geringem Eisenverlust, nicht verschlechtert durch Spannungsfreiglühen, und Verfahren zu dessen Herstellung Expired EP0143548B1 (de)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP58201279A JPS6092479A (ja) 1983-10-27 1983-10-27 歪取り焼鈍によつて特性が劣化しない低鉄損の方向性けい素鋼板およびその製造方法
JP58201281A JPS6092481A (ja) 1983-10-27 1983-10-27 歪取り焼鈍によつて特性が劣化しない低鉄損の方向性けい素鋼板およびその製造方法
JP201280/83 1983-10-27
JP58201280A JPS6092480A (ja) 1983-10-27 1983-10-27 歪取り焼鈍によつて特性が劣化しない低鉄損の方向性けい素鋼板およびその製造方法
JP201279/83 1983-10-27
JP201281/83 1983-10-27

Publications (2)

Publication Number Publication Date
EP0143548A1 EP0143548A1 (de) 1985-06-05
EP0143548B1 true EP0143548B1 (de) 1988-08-24

Family

ID=27327923

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84307320A Expired EP0143548B1 (de) 1983-10-27 1984-10-24 Kornorientiertes Siliziumstahlblech mit geringem Eisenverlust, nicht verschlechtert durch Spannungsfreiglühen, und Verfahren zu dessen Herstellung

Country Status (2)

Country Link
EP (1) EP0143548B1 (de)
DE (1) DE3473679D1 (de)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1278985C (en) * 1985-04-30 1991-01-15 Allegheny Ludlum Corporation Grain-oriented silicon steel and stress coating therefor
US5185043A (en) * 1987-12-26 1993-02-09 Kawasaki Steel Corporation Method for producing low iron loss grain oriented silicon steel sheets
JPH0670256B2 (ja) * 1987-12-26 1994-09-07 川崎製鉄株式会社 歪取り焼鈍によって特性が劣化しない低鉄損方向性珪素鋼板の製造方法
GB9309338D0 (en) * 1993-05-06 1993-06-16 Orb Elect Steels Ltd Coating of steels
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
KR102407899B1 (ko) 2017-09-28 2022-06-10 제이에프이 스틸 가부시키가이샤 방향성 전기 강판

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5317757B2 (de) * 1973-09-21 1978-06-10
JPS5423647B2 (de) * 1974-04-25 1979-08-15
JPS585968B2 (ja) * 1977-05-04 1983-02-02 新日本製鐵株式会社 超低鉄損一方向性電磁鋼板の製造方法
JPS5518566A (en) * 1978-07-26 1980-02-08 Nippon Steel Corp Improving method for iron loss characteristic of directional electrical steel sheet
US4363677A (en) * 1980-01-25 1982-12-14 Nippon Steel Corporation Method for treating an electromagnetic steel sheet and an electromagnetic steel sheet having marks of laser-beam irradiation on its surface

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PROCEEDINGS OF THE SYMPOSIUM ON MAGNETISM AND MAGNETIC MATERIALS, 9th-12th December 1975, Philadelphia, pages 574-575, American Institute of Physics, New York, US; T. IRIE et al: "Effect of insulating coating on domain structure in grain oriented 3% Si-Fe sheet as observed with a high voltage scanning electron microscope" *

Also Published As

Publication number Publication date
DE3473679D1 (en) 1988-09-29
EP0143548A1 (de) 1985-06-05

Similar Documents

Publication Publication Date Title
KR100297046B1 (ko) 매우철손이낮은방향성전자강판과그제조방법
EP0202339B1 (de) Verfahren zur herstellung von gleichgerichteten elektroblechen mit geringen eisenverlusten
EP0033878B1 (de) Verfahren zum Behandeln eines elektromagnetischen Stahlbleches mit Laserstrahlen
US4952253A (en) Grain-oriented silicon steel sheet having a low iron loss free from deterioration due to stress-relief annealing and a method of producing the same
EP3653759A1 (de) Orientiertes elektromagnetisches stahlblech und verfahren zur herstellung davon
EP0143548B1 (de) Kornorientiertes Siliziumstahlblech mit geringem Eisenverlust, nicht verschlechtert durch Spannungsfreiglühen, und Verfahren zu dessen Herstellung
US5173129A (en) Grain-oriented silicon steel sheet having a low iron loss free from deterioration due to stress-relief annealing and a method of producing the same
US4964922A (en) Method for domain refinement of oriented silicon steel by low pressure abrasion scribing
JPH028027B2 (de)
JPS636610B2 (de)
EP0345937B1 (de) Verfahren zur Veredelung der magnetischen Bereiche von elektrischen Stählen
JPH029111B2 (de)
JPH0680172B2 (ja) 鉄損の低い方向性けい素鋼板およびその製造方法
JP2671084B2 (ja) 鉄損特性の優れる高磁束密度方向性電磁鋼板及びその製造方法
JPS6139395B2 (de)
US5041170A (en) Method employing skin-pass rolling to enhance the quality of phosphorus-striped silicon steel
JPH0615696B2 (ja) 鉄損の低い一方向性電磁鋼板の製造方法
JPS6319573B2 (de)
JPH0337843B2 (de)
JP2738620B2 (ja) 加工性の優れた高磁束密度超低鉄損方向性電磁鋼板及びその製造方法
JPH028028B2 (de)
JPH0218392B2 (de)
JPH01198430A (ja) 極めて鉄損が優れ、被膜密着性の優れた方向性電磁鋼板の製造方法
JPS61246375A (ja) 歪取り焼鈍による特性の劣化がない低鉄損方向性けい素鋼板およびその製造方法
JPS63232302A (ja) 歪取り焼鈍によって特性が劣化しない低鉄損の方向性けい素鋼板

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE FR GB IT SE

17P Request for examination filed

Effective date: 19850930

17Q First examination report despatched

Effective date: 19860527

R17C First examination report despatched (corrected)

Effective date: 19870202

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT SE

REF Corresponds to:

Ref document number: 3473679

Country of ref document: DE

Date of ref document: 19880929

ET Fr: translation filed
ITF It: translation for a ep patent filed

Owner name: SOCIETA' ITALIANA BREVETTI S.P.A.

PLBI Opposition filed

Free format text: ORIGINAL CODE: 0009260

26 Opposition filed

Opponent name: THYSSEN STAHL AG

Effective date: 19890522

ITTA It: last paid annual fee
PLBN Opposition rejected

Free format text: ORIGINAL CODE: 0009273

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: OPPOSITION REJECTED

27O Opposition rejected

Effective date: 19911012

EAL Se: european patent in force in sweden

Ref document number: 84307320.6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19971015

Year of fee payment: 14

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19981025

EUG Se: european patent has lapsed

Ref document number: 84307320.6

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20031003

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20031022

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20031103

Year of fee payment: 20

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20041023

REG Reference to a national code

Ref country code: GB

Ref legal event code: PE20