EP0589418A1 - Process for producing oriented electrical steel sheet having minimized primary film, excellent magnetic properties and good workability - Google Patents

Process for producing oriented electrical steel sheet having minimized primary film, excellent magnetic properties and good workability Download PDF

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Publication number
EP0589418A1
EP0589418A1 EP93115198A EP93115198A EP0589418A1 EP 0589418 A1 EP0589418 A1 EP 0589418A1 EP 93115198 A EP93115198 A EP 93115198A EP 93115198 A EP93115198 A EP 93115198A EP 0589418 A1 EP0589418 A1 EP 0589418A1
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Prior art keywords
steel sheet
annealing
mgo
process according
weight
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EP93115198A
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German (de)
English (en)
French (fr)
Inventor
Hotaka c/o NIPPON STEEL CORPORATION Honma
Osamu c/o Nippon Steel Corporation Tanaka
Hiroaki c/o Nippon Steel Corporation Masui
Katsuro C/O Nippon Steel Corporation Kuroki
Tsutomu c/o NIPPON STEEL CORPORATION Haratani
Masao C/O Nippon Steel Corporation Ono
Isao c/o Nippon Steel Corporation Iwanaga
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Nippon Steel Corp
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Nippon Steel Corp
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Priority claimed from JP4251532A external-priority patent/JPH06100937A/ja
Priority claimed from JP4251533A external-priority patent/JPH06100997A/ja
Priority claimed from JP4284786A external-priority patent/JPH06136446A/ja
Application filed by Nippon Steel Corp filed Critical Nippon Steel Corp
Publication of EP0589418A1 publication Critical patent/EP0589418A1/en
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    • 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
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1277—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular surface treatment
    • C21D8/1283—Application of a separating or insulating coating
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • 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
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
    • C23C22/24—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing hexavalent chromium compounds
    • C23C22/33—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing hexavalent chromium compounds containing also phosphates
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process
    • C23C22/74—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process for obtaining burned-in conversion coatings
    • 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
    • H01F1/18—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 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
    • C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
    • C21D8/1266—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest between cold rolling steps
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
    • C21D8/1272—Final recrystallisation annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1277—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular surface treatment
    • C21D8/1288—Application of a tension-inducing coating

Definitions

  • the present invention relates to a process for producing an oriented electrical steel sheet having excellent magnetic properties.
  • the steel sheet is coated with a slurry of a fine powder of magnesia (magnesium oxide MgO) in water, optionally dried and then baked in the step of high-temperature finish annealing which also serves as secondary recrystallization annealing wherein MgO is reacted with SiO2 or Si to form a ceramic insulating primary film, i.e., forsterite (Mg2SiO4).
  • Mg2SiO4 ceramic insulating primary film
  • the forsterite imparts tension to the steel sheet, which is useful for improving magnetic properties, especially iron loss (transformer efficiency).
  • the effect of the inhibitor which serves to preferentially grow grains having a Goss orientation with the formation of grains having other orientations being inhibited, cannot be exhibited during the temperature rise, which provides a steel sheet having very poor magnetic properties and comprising fine grains because the growth of secondary recrystallized grains having a Goss orientation has been effected partially or not at all.
  • titanium oxides (TiO2 etc.) or other compounds are added to the MgO to form a denser primary film.
  • the primary film composed mainly of forsterite is a solid substance, there occurs a problem of working, such as shearing of products, which leads to a lowering in the service life of tools.
  • the present invention clarifies the above-described problems and minimizes the formation of a solid substance composed mainly of forsterite, i.e., a primary film, based on the following technical finding, to thus provide a process for producing a grain oriented electrical steel sheet having a high magnetic flux density, good workability and a very low iron loss value.
  • the present inventors have studied on the relationship between the average thickness of the primary film, composed mainly of forsterite, on the surface of the steel sheet and the magnetic properties and, as a result, have found the following facts.
  • a hot-rolled steel sheet for an oriented electrical steel sheet having a chemical composition specified in Table 1 was quenched after annealing, pickled, cold-rolled to a thickness of 0.23 mm, subjected to primary recrystallization annealing and coated with various annealing separators comprising an MgO powder and, added thereto, (S) sulfur compounds with the S content being varied.
  • the coated steel sheets were subjected to finish annealing to form primary films having various average thicknesses and coated with an insulating coating having tension to provide oriented electrical steel sheet samples which were then subjected to measurement for magnetic flux density.
  • Fig. 1 The results are shown in Fig. 1.
  • S content the proportion of weight of S per 100 of weight of MgO
  • the primary film is not reduced and the thickness thereof does not become 0.3 ⁇ m or less.
  • S content exceeds 10%, the surface of the steel sheet is roughened, which not only has an adverse effect on the magnetic properties but also gives rise to a lowering in the integration density in the orientation of the secondary recrystallized grains, so that no satisfactory effect of lowering the iron loss can be attained due to a lowering in the magnetic flux density.
  • the S compound can minimize the thickness of the primary film and further has an important effect that nitriding during finish annealing can be inhibited.
  • MnS and AlN are used as the inhibitor in the secondary recrystallization.
  • MnS disappears at a relatively low temperature to optimize the primary recrystallization structure.
  • AlN leads to development of secondary recrystallization to provide a good secondary recrystallized structure.
  • nitriding occurs during finish annealing, since the inhibitor is excessively strengthened and the optimization of the primary recrystallized structure by the disappearance of MnS cannot be attained, the sharpness of Goss texture in the orientation of the secondary recrystallized grains deteriorates.
  • the addition of the S compound to the annealing separator inhibits the penetration of nitrogen into the steel sheet.
  • the formation of the primary film inhibits the penetration of nitrogen to some extent.
  • the S compound is added to inhibit the formation of the primary film and, at the same time, to inhibit nitriding, thereby providing a good orientation sharpness of Goss texture.
  • At least one of these additives may further be added in an amount of 1 to 15 parts by weight in terms of the total amount of Cl, (CO3) ⁇ 2, (NO3) ⁇ 2 and (SO4) ⁇ 2 based on 100 parts by weight of MgO.
  • Examples of the above-described additives contemplated in the present invention include a sulfide, or a chloride, a carbonate, a nitrate and a sulfate of Li, K, Bi, Na, Ba, Ca, Mg, Zn, Fe, Zr, Sn, Sr, Al, etc.
  • at least one of sulfides of the above-described elements is added in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of MgO, or at least one of compounds, such as chlorides, carbonates, etc. of the above-described elements, is added in an amount of 2 to 20 parts by weight based on 100 parts by weight of MgO.
  • the chlorides and the like are very useful for accelerating the action of reducing the primary film on the surface of the steel sheet.
  • Cl ions react directly with a matrix at the interface of the primary film and the matrix to form a chloride at the interface of the primary film and the matrix, which strongly promotes the peeling of the primary film. Therefore, it is necessary to add the chlorides etc. when no satisfactory effect is attained by using the S compound alone or the yield is deteriorated due to the presence of sites where the secondary recrystallization could not be sufficiently developed because of uneven decarburization, finish annealing, etc.
  • the primary film is more effectively inhibited by virtue of the combined effect, which enables the presence of the primary film on the steel sheet to be brought to substantially zero.
  • a grain oriented electrical steel sheet having a chemical composition specified in Table 2 was hot-rolled, and the hot-rolled sheet was quenched after annealing and cold-rolled to a thickness of 0.23 mm. Grooves having a depth of 15 ⁇ m were provided, at a pitch of 5 mm by using a roll, in the direction of the width of the steel sheet, and the steel sheet was then subjected to primary recrystallization annealing, coated with various annealing separators comprising a MgO powder and, added thereto, various compounds, subjected to the coated steel sheets to finish annealing to form primary films having various average thicknesses and coated with an insulating coating having tension to provide oriented electrical steel sheet samples which were then subjected to measurements for iron loss.
  • the present inventors have made further studies and, as a result, have confirmed that grooving during the primary recrystallization annealing or the intermediate step before or after the primary recrystallization annealing in addition to the above-described step of cold rolling can provide a satisfactory magnetic domain division effect.
  • the steel sheet was then cooled, coated with various annealing separators comprising a MgO powder and, various compounds, subjected to finish annealing to form primary films having various average thicknesses and coated with an insulating coating having tension to provide grain oriented electrical steel sheet samples which were then subjected to measurements for iron loss.
  • the results are shown in Fig. 3.
  • the iron loss improves with a reduction in the thickness of the primary film, and this tendency is particularly significant when the thickness of the primary film is 0.3 ⁇ m or less.
  • grooves having an average depth of 1 to 50 ⁇ m and an average width of 500 ⁇ m or less in a regular arrangement in a direction at an angle of 45 to 90° to the longitudinal direction of rolling of the steel sheet by a mechanical, chemical, optical, thermal, electrical or other energy irradiation method. This is because the grooves enable the magnetic domain of the product to be more finely divided, which contributes to a reduction of the iron loss.
  • the grooves may be provided by any means, for example, a mechanical method using a grooved roll, a grooved or sprocket press, etc., an energy irradiation method using a laser beam, a plasma, etc., a method wherein water, an oil or the like is blown against the steel sheet at a high pressure, chemical etching with an acid or like, electrical etching or a method comprising a combination of the above methods so far as the formed grooves satisfy the above-described requirements.
  • a mechanical method using a grooved roll, a grooved or sprocket press, etc. an energy irradiation method using a laser beam, a plasma, etc.
  • a method wherein water, an oil or the like is blown against the steel sheet at a high pressure
  • chemical etching with an acid or like electrical etching or a method comprising a combination of the above methods so far as the formed grooves satisfy the above-described requirements.
  • the thickness of the primary film is 0.3 ⁇ m or less, a combination of the primary film with the above-described grooves contributes to a remarkable improvement in the magnetic properties. The reason for this has not been elucidated yet.
  • the present invention has been completed based on the above-described studies and observations.
  • the electrical steel sheet to which the present invention is applicable, is limited to a steel comprising Al as a main ingredient besides Si and a main inhibitor comprising Si3N4 or AlN or MnS in the case of a steel having a high S content. It is a matter of course that the addition of other additive elements, such as Sn, Se, Sb, Cu, Bi, Nb, Ti, V and Ni as auxiliary elements, besides Si and Al, for the purpose of improving the magnetic properties does not change the subject matter of the present invention.
  • additive elements such as Sn, Se, Sb, Cu, Bi, Nb, Ti, V and Ni as auxiliary elements, besides Si and Al, for the purpose of improving the magnetic properties does not change the subject matter of the present invention.
  • this production process is characterized in that, in a steel having a Si content of 2.5 to 4.5%, Al is contained in an amount of 0.010 to 0.050% in terms of the amount of an acid solved Al during the production of the steel by the melt process and N is added in an amount of 0.0030 to 0.0120% during the production of the steel by the melt process. S and Mn are incorporated in respective amounts of 0.008 to 0.06% and 0.03 to 0.20%.
  • Al is useful for forming an AlN inhibitor and should be present in an amount of at least 0.010% in terms of the amount of acid solved Al during the production of the steel by the melt process. In the present invention, however, when the amount of Al exceeds 0.050% in terms of the acid solved Al content, not only no suitable amount of AlN is formed but also the amount of formation of Al2O3 is increased, which is detrimental to the purity of the steel and has an adverse effect of the magnetic properties.
  • N is indispensable to the formation of Si3N4 and AlN inhibitors and, in the present invention, should be present in an amount of at least 0.0030% after the completion of the primary annealing, that is, during the production of the steel by the melt process.
  • the N content exceeds 0.0120%, an excessive amount of Al or Si is consumed, which is unfavorable for secondary recrystallization.
  • S is necessary in an amount of at least 0.008% during the production of the steel by the melt process for the purpose of effectively using MnS as the inhibitor when a positive utilization of S is intended.
  • S content exceeds 0.06%, MnS unfavorably aggregates. The same effect can be attained when sulfurizing is effected by any method before the secondary recrystallization.
  • Mn is necessary for the formation of MnS and should be present in an amount of at least 0.03% during the production of the steel by the melt process. When the Mn content exceeds 0.20%, it becomes difficult to form MnS.
  • C is necessary for ensuring the amount of ⁇ phase in the hot rolling and should be present in an amount of at least 0.03% for ensuring the magnetic properties contemplated in the present invention.
  • the C content exceeds 0.120%, it becomes difficult to provide a favorable aggregate structure in the primary recrystallization annealing.
  • elements are not particularly characteristic as compared with elements used in the conventional steel, elements such as Sn, Se, Sb, Cu, B, Nb, Ti, V and Ni can improving the magnetic properties and the use thereof does not change the subject matter of the present invention.
  • a molten steel which has been tapped in a converter or an electric furnace and optionally subjected to refining to regulate the composition, is subjected to continuous casting, ingot making/slabbing, thin slab continuous casting to omit the hot rolling or the like and to provide a slab having a thickness of 30 to 400 mm (50 mm or less in the case of thin slab continuous casting).
  • the lower limit of the thickness is 30 mm from the viewpoint of the productivity
  • the upper limit of the thickness is 400 mm from the viewpoint of preventing abnormal distribution of Al2O3 due to center segregation.
  • the upper limit of the thickness is 50 mm from the viewpoint of suppressing the formation of coarse grains caused by a reduction in the cooling rate.
  • the slab thus obtained is reheated to 1,200°C or above by gas heating, electric heating or the like and subsequently hot-rolled into a hot coil having a thickness of 10 mm or less.
  • the lower limit of the reheating temperature is 1,200°C from the viewpoint of melting MnS and AlN.
  • the upper limit of the thickness of the hot coil is 10 mm from the viewpoint of attaining a cooling rate capable of forming proper precipitates.
  • the thickness is preferably 10 mm or less.
  • the hot coil thus provided is again annealed at 800 to 1250°C and then subjected to water cooling, air cooling or other treatment or a combination thereof to suitably improve the magnetic properties.
  • the lower limit of the annealing temperature is 800°C from the viewpoint of dissolving AlN, while the upper limit, for preventing the coarsening of AlN grains is 1250°C.
  • the hot coil is pickled in a direct or batch manner and then subjected to cold rolling.
  • the cold rolling is effected with a reduction ratio of 60 to 95%.
  • the lower limit of the reduction ratio is 60% from the viewpoint of recrystallization, preferably 70% from the viewpoint of increasing grains having a ⁇ 111 ⁇ 112 ⁇ orientation in the primary annealing to accelerate the formation of grains having a Goss orientation in the secondary recrystallization annealing.
  • the reduction ratio exceeds 95%, grains unfavorable for the magnetic properties called "deviated Goss grains", which are grains having a Goss orientation rotated within the plane, occur during the secondary recrystallization annealing.
  • the above-described process is the so-called “single cold rolling process”.
  • double cold rolling process wherein cold rolling is effected twice with annealing between the cold rollings (i.e., cold rolling-annealing-cold rolling is effected)
  • the reduction ratio of the first cold rolling and the reduction ratio of the second cold rolling are 10 to 80% and 50 to 95%, respectively.
  • 10% is the minimum reduction ratio of the first cold rolling necessary for the recrystallization
  • 80% and 95% are respectively the upper reduction ratios for the first cold rolling and the second cold rolling limited from the viewpoint of forming proper grains having a Goss orientation during the secondary recrystallization
  • 50% is the lower reduction ratio of the second cold rolling necessary for properly forming grains having a ⁇ 111 ⁇ 112 ⁇ orientation formed in the primary annealing in the double cold rolling process.
  • inter-pass aging wherein the steel sheet is heated to a temperature in the range of from 100 to 400°C is also useful for improving the magnetic properties.
  • the aging temperature is below 100°C, no aging effect can be attained, while when it exceeds 400°C, the dislocation is unfavorably recovered.
  • the steel sheet is then subjected to primary recrystallization annealing.
  • the formation of grooves at a temperature in the range from 300 to 950°C in the course of or before or after the primary recrystallization annealing is important to the present invention.
  • the temperature of the steel sheet is preferably 600°C or above.
  • it exceeds 950°C since the primary crystallized grains are coarsened, a Goss orientation favorable to iron loss cannot be provided during the secondary recrystallization.
  • the grooves may be formed during any of the first annealing and the second annealing. Alternatively, the formation of the grooves may be divided between the first annealing and the second annealing.
  • the grooves thus provided remain after the completion of the finish annealing, and the combined effect of the grooves and the minimized primary film composed mainly of forsterite and having an average thickness as small as 0.3 ⁇ m provides a low iron loss value unattainable by the prior art.
  • the reason why the thickness of the primary film is preferably 0.3 ⁇ m or less is as described above, and when the thickness exceeds 0.3 ⁇ m, no sufficient iron loss value is provided by grooving in the intermediate step according to the present invention.
  • the method of forming grooves is as described above, when the average depth of the grooves is less than 1 ⁇ m, no magnetic domain division effect can be attained. On the other hand, when the average depth of the grooves exceeds 50 ⁇ m, the depth is excessively large, which prevents smooth flow of the magnetic flux, so that the iron loss becomes poor. It is preferably 5 to 30 ⁇ m.
  • the grooves are preferably arranged in a regular manner. This is because the magnetic domain can be regularly divided. In general, it is preferred for the grooves to be provided at a substantially constant pitch having an angle of 45 to 90° (right angle) to the longitudinal direction of the steel sheet.
  • the pitch of the grooves is preferably 2 to 20 mm.
  • the pitch is less than 2 mm, the magnetic domain is excessively divided, which leads to an increase in 90° domain, so that the magnetic strain as well as the iron loss becomes poor.
  • the pitch of the grooves exceeds 20 mm, the effect of dividing the magnetic domain cannot be attained.
  • the primary recrystallization annealing is effected in both the single cold rolling process and the second cold rolling process. It is useful to effect decarburization in the annealing.
  • C is not only unfavorable to the growth of the secondary recrystallized grains but also leads to a deterioration in the iron loss when it remains as an impurity. It is preferred for the C content to be lowered in the stage of production of the steel by the melt process because the step of decarburization can be shortened and, further, grains having a ⁇ 111 ⁇ 112 ⁇ orientation are increased. Setting of a proper dew point in the primary crystallization serving also as decarburization annealing enables an oxide layer necessary for the subsequent formation of the primary film to be ensured.
  • the primary recrystallization annealing temperature is preferably 700 to 950°C.
  • the lower limit of the primary recrystallization annealing temperature is 700°C from the viewpoint of causing the recrystallization, while the upper limit is 950°C from the viewpoint of preventing the occurrence of coarse grains.
  • the amount of oxidation in the primary recrystallization annealing be 1000 ppm or less in terms of the [O] content and the FeO/SiO2 is 0.25 or less.
  • the [O] content exceeds 100 ppm, the SiO2 content and FeO content of the oxide film inevitably become high and the thickness of the oxide film increases, which is disadvantageous in the glass film decomposition reaction during the high temperature finish annealing.
  • the amount of oxidation is preferably 400 to 800 ppm in terms of the [O] content.
  • the FeO/SiO2 ratio is preferably 0.25 or less.
  • a magnesium oxide (composed mainly of MgO; hereinafter referred to as "MgO”) powder is dissolved in water or an aqueous solution composed mainly of water and coated in a slurry form on the steel sheet.
  • MgO magnesium oxide
  • a very small amount of a suitable compound is added for the purpose of accelerating a forsterite formation reaction that facilitates the melting of the MgO powder during the subsequent secondary recrystallization annealing.
  • the amount thereof added is preferably 1 to 15%.
  • the lower limit of 1% is from the viewpoint of attaining the effect of accelerating the forsterite reaction.
  • the proportion of MgO becomes so small that the forsterite reaction does not proceed.
  • Antimony compounds such as Sb2(SO4)3, have the effect of melting MgO at a relatively low temperature.
  • the amount of addition thereof is preferably 0.05 to 5%.
  • the lower limit of the amount of addition thereof is 0.05% from the viewpoint of causing the above-described melting at a low temperature.
  • the amount of addition exceeds 5%, a proper reaction for the formation of forsterite from MgO is inactivated.
  • Boron compounds such as Na2B4O7, and strontium/barium and carbide/nitride compounds having the same function as the boron compounds, have the effect of melting MgO at somewhat higher temperature than that for the antimony compounds.
  • the amount of addition thereof is preferably 0.05 to 5%.
  • the lower limit of the amount of addition thereof is 0.05% from the viewpoint of attaining the above-described effect.
  • the amount of addition thereof exceeds 5%, a proper reaction for the formation of forsterite from MgO is inactivated.
  • These compounds may be added in the form of a combination thereof.
  • the amount of addition of the compounds is expressed as a percentage of the weight proportion of the compound per 100 parts by weight of MgO.
  • an annealing separator comprising a MgO powder and, added and mixed therewith, a S compound having a S content of 0.5 to 10%.
  • the thickness of the primary film exceeds 0.3 ⁇ m, while when it exceeds 10%, the magnetic flux density lowers.
  • the above-described annealing separator may further comprise at least one member selected from the group consisting of Cl compounds, carbonates, nitrates and sulfates in an amount of 1 to 15% in terms of the total amount of Cl, (CO3) ⁇ 2, (NO3) ⁇ 2 and (SO4) ⁇ 2. This can more effectively inhibit the formation of the primary film, so that the thickness of the primary film can be brought to substantially zero.
  • the annealing separators may comprise a MgO powder and, added and mixed therewith, 0.5 to 20% of at least one of sulfides of Li, K, Bi, Na, Ba, Ca, Mg, Zn, Fe, Zr, Sn, Sr, Al, etc. and/or 2 to 20% of at least one of carbonates, nitrates and chlorides of these elements.
  • the amount of the sulfide is less than 0.5%, the primary film cannot be effectively reduced.
  • it exceeds 20% by weight the film formation process becomes so unstable that it is difficult to attain the high magnetic flux density and low iron loss contemplated in the present invention.
  • the object of the present invention cannot be attained also when the amount of the carbonates, nitrates and chlorides of the above elements is less than 2% or exceeds 20%.
  • water of hydration of MgO is also important and limited to 0.5 to 5.0%.
  • the content of water of hydration is less than 0.5%, the reactivity of MgO is deteriorated.
  • it exceeds 5.0% the dew point in an atmosphere between the steel sheets becomes so high that an uneven oxide film occurs on the surface of the steel sheet, which makes it impossible to have an even, very thin primary film or a non-primary film.
  • the maximum arrival temperature is preferably 1100 to 1300°C.
  • the lower limit temperature is 1100°C from the viewpoint of ensuring the secondary recrystallization.
  • the temperature exceeds 1300°C, the grains are excessively coarsened, which leads to an increase in the iron loss.
  • the primary film composed mainly of forsterite becomes remarkably reduced or absent by virtue of the effect of the addition of special additives to the MgO powder, so that the nitrogen compound inhibitors (such as AlN and Si3N4) necessary for the secondary recrystallization in the annealing are likely to escape during finish annealing.
  • the function of MnS as an inhibitor is also important. For this reason, it is important to prevent the penetration of N into the steel by regulating the partial pressure of nitrogen (P N2 ) in the atmosphere gas during the finish annealing to 25% or less, which enables secondary recrystallization to be stably effected.
  • the addition of the S compound to the annealing separator inhibits nitriding during finish annealing to enable grains having a more sound Goss orientation to be stably grown.
  • the second crystallization temperature is below 700°C, N does not penetrate into the steel, while when the temperature exceeds the maximum arrival temperature, the secondary recrystallization or the like is unfavorably completed.
  • this annealing is effected in a hydrogen atmosphere because it becomes possible to attain a further effect of the present invention that secondary recrystallized grains having an excellent Goss orientation can be provided.
  • the high-temperature finish annealing when the heating rate is excessively high, the inhibitor is likely to escape before the satisfactory recrystallization occurs.
  • stable magnetic properties can be provided by limiting the heating rate to 30 °C/hr or less.
  • the coating of the steel sheet after the secondary recrystallization with a high tension film (coating) having an organic or inorganic insulating film in combination with a heat treatment or the like or the coating of such a film by a sol-gel process is especially important for the purpose of improving insulating properties and magnetic properties.
  • the reason for this is that, in the present invention, since the primary film having a high tension property, such as forsterite, is minimized or absent, the coating of an insulating film having a high tension property is effective to compensate for the minimized primary film or the absence of the primary film.
  • a material comprising, in terms of weight, 0.056% of C, 3.35% of Si, 0.10% of Mn, 0.27% of acid solved Al, 0.0070% of N and 0.0165% of S with the balance consisting of Fe and unavoidable impurities was hot-rolled to a thickness of 2.0 mm, annealed at 1120°C for 2 min, pickled, cold-rolled to a final steel sheet thickness of 0.225 mm. Then, the steel sheet was subjected to decarburization annealing at 850°C for 3 min in an atmosphere comprising 25% of N2 and 75% of H2 and having a dew point of 55°C. In this case, the oxygen content of the steel sheet was 600 ppm.
  • the steel sheet was coated with an annealing separator having a composition specified in Table 4 and then subjected to final finish annealing under atmosphere conditions (A) and (B) specified in Table 5. Subsequently, the annealed steel sheet was coated with a solution comprising 100 ml of 20% colloidal silica, 50 ml of 50% Al(H2PO4) and 5g of CrO3 at a coverage after drying of 6 g/m2 and subjected to heat flattening and baking at 880°C for 45 sec.
  • the film properties of surface of the steel sheet and the workability of the steel sheet are given in Table 5.
  • Steels comprising chemical ingredients specified in Tables 6 and 9 were prepared by a melt process in a converter, and steel sheets were prepared under conditions specified in Tables 7, 8, 10 and 11. Some of the hot-rolled sheets were annealed under conditions of 1120°C for 30 sec and cooled with water after the completion of the annealing. All the samples except for sample F were subjected to inter pass aging at 250°C. The formation of grooves was effected after or during cold rolling. Thereafter, the steel sheets were subjected to primary annealing.
  • the steel sheets were coated with a powder.
  • the powder was dissolved in water to form a slurry that was then coated on the steel sheets and dried at 350°C.
  • the amount of addition of a compound is expressed as a percentage of the weight proportion of the compound per 100 parts by weight of MgO.
  • the coated sheet sheets were subjected to secondary recrystallization annealing at various average heating rates in a temperature range of from 700°C to the maximum arrival temperature. In this case, the maximum arrival temperature was 1,200°C.
  • the steel sheets were heat-coated with a high-tension insulating film (a secondary film) comprising a phosphoric acid compound, subjected to blanking and stress relieving annealing at 850°C for 4 hr in a dry atmosphere comprising 90% of N2 and 10% of H2 and subjected to a magnetic measurement test.
  • a high-tension insulating film (a secondary film) comprising a phosphoric acid compound
  • the magnetic measurement was effected by the SST testing method for a single sheet having a size of 60 ⁇ 300 mm.
  • the B8 value [magnetic flux density (Tesla) at 800 A/m] and W 17/50 (iron loss value (w/kg) in 1.7 Tesla at 50 Hz) and W 13/50 (iron loss value (w/kg) in 1.3 Tesla at 50 Hz) were measured.
  • Steels comprising chemical ingredients specified in Table 12 were produced in a converter, and grain oriented electrical steel sheets were produced under conditions specified in Tables 13 and 14. Some of the hot-rolled sheets were annealed under conditions of 1,120°C at 30 sec and cooled with water after the completion of the annealing. All the samples except for sample F were subjected to between-pass aging at 250°C. Thereafter, the steel sheets were subjected to primary annealing. The formation of groove was effected during the primary annealing. Further, the steel sheets were coated with a powder. In this case, the powder was dissolved in water to form a slurry that was then coated on the steel sheets and dried at 350°C. In this connection, the amount of addition of a compound is expressed as a percentage of the weight proportion of the compound per 100 parts by weight of MgO.
  • the coated sheet sheets were subjected to secondary recrystallization annealing at various average temperature rise rates in a temperature range of from 700°C to the maximum arrival temperature.
  • the maximum arrival temperature was 1,200°C.
  • the steel sheets were heat-coated with a high-tension insulating film (a secondary film) comprising a phosphoric acid compound, subjected to blanking and stress relieving annealing at 850°C for 4 hr in a dry atmosphere comprising 90% of N2 and 10% of H2 and subjected to a magnetic measurement test. The results are given in Table 14.
  • All the maximum depth, pitch and angle to the rolling direction of grooves are measurements for products after the completion of the secondary recrystallization annealing.
  • the magnetic measurement was effected by the SST testing method for a single sheet having a size of 60 ⁇ 300 mm.
  • the B8 value [magnetic flux density (Tesla) at 800 A/m] and W 17/50 (iron loss value (w/kg) in 1.7 Tesla at 50 Hz) and W 13/50 (iron loss value (w/kg) in 1.3 Tesla at 50 Hz) were measured.

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EP93115198A 1992-09-21 1993-09-21 Process for producing oriented electrical steel sheet having minimized primary film, excellent magnetic properties and good workability Withdrawn EP0589418A1 (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP4251532A JPH06100937A (ja) 1992-09-21 1992-09-21 グラス被膜を有しない極めて鉄損の優れた珪素鋼板の製造法
JP251532/92 1992-09-21
JP251533/92 1992-09-21
JP4251533A JPH06100997A (ja) 1992-09-21 1992-09-21 グラス被膜を有しない磁気特性の優れた珪素鋼板及びその製造法
JP284786/92 1992-10-22
JP4284786A JPH06136446A (ja) 1992-10-22 1992-10-22 グラス被膜を有しない鉄損の優れた方向性電磁鋼板の製造法

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0684322A3 (en) * 1994-05-23 1996-05-22 Kaisui Kagaku Kenkyujo Kk Ceramic coating and manufacturing process.
WO1999053107A1 (de) * 1998-04-09 1999-10-21 Koenigbauer Georg Verfahren zur herstellung eines forsterit-isolationsfilms auf einer oberfläche von korn-orientierten, anisotropen elektrotechnischen stahlblechen
EP1992708A1 (en) * 2006-03-07 2008-11-19 Nippon Steel Corporation Process for producing grain-oriented magnetic steel sheet with excellent magnetic property
EP2615184A1 (en) * 2010-09-09 2013-07-17 Nippon Steel & Sumitomo Metal Corporation Oriented electromagnetic steel sheet and process for production thereof
EP2615189A1 (en) * 2010-09-10 2013-07-17 JFE Steel Corporation Grain-oriented magnetic steel sheet and process for producing same
EP2623634A1 (en) * 2010-09-30 2013-08-07 JFE Steel Corporation Oriented electromagnetic steel plate
EP2799594A4 (en) * 2011-12-28 2015-08-26 Jfe Steel Corp DIRECTIONAL ELECTROMAGNETIC STEEL SHEET HAVING A COATING, AND METHOD FOR MANUFACTURING THE SAME
CN104884646A (zh) * 2012-12-28 2015-09-02 Posco公司 取向电工钢板及其制造方法
EP2623633A4 (en) * 2010-09-28 2017-11-01 JFE Steel Corporation Oriented electromagnetic steel plate
US10793929B2 (en) 2013-07-24 2020-10-06 Posco Grain-oriented electrical steel sheet and method for manufacturing same
CN113166950A (zh) * 2018-11-30 2021-07-23 Posco公司 取向电工钢板及其制造方法
US11984249B2 (en) 2018-01-31 2024-05-14 Jfe Steel Corporation Grain-oriented electrical steel sheet, wound transformer core using the same, and method for producing wound core

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5360272B2 (ja) * 2011-08-18 2013-12-04 Ｊｆｅスチール株式会社 方向性電磁鋼板の製造方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3440344A1 (de) * 1984-01-09 1985-07-18 Nippon Steel Corp., Tokio/Tokyo Verfahren zur herstellung von kornorientiertem elektrostahlblech mit verbesserten magnetischen eigenschaften und verbesserten glasfilmeigenschaften
EP0394696A1 (en) * 1989-03-30 1990-10-31 Nippon Steel Corporation Method of producing grain oriented electrical steel sheet having high magnetic flux density
EP0525467A2 (en) * 1991-07-10 1993-02-03 Nippon Steel Corporation Grain oriented silicon steel sheet having excellent primary glass film properties

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3440344A1 (de) * 1984-01-09 1985-07-18 Nippon Steel Corp., Tokio/Tokyo Verfahren zur herstellung von kornorientiertem elektrostahlblech mit verbesserten magnetischen eigenschaften und verbesserten glasfilmeigenschaften
US4543134A (en) * 1984-01-09 1985-09-24 Nippon Steel Corporation Process for producing grain-oriented electrical steel sheet having both improved magnetic properties and properties of glass film
EP0394696A1 (en) * 1989-03-30 1990-10-31 Nippon Steel Corporation Method of producing grain oriented electrical steel sheet having high magnetic flux density
EP0525467A2 (en) * 1991-07-10 1993-02-03 Nippon Steel Corporation Grain oriented silicon steel sheet having excellent primary glass film properties

Non-Patent Citations (8)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 104, no. 12, March 24, 1986, Columbus, Ohio, USA TANAKA OSAMU et al. "Direc- tional electromagnetic steel strip.", page 301, column 2, abstract-no. 93 360 w *
CHEMICAL ABSTRACTS, vol. 104, no. 4, January 27, 1986, Columbus, Ohio, USA TANAKA OSAMU et al. "Ani- sotropic silicon steel sheet having high magnetic and coating characteristics.", page 201, column 2, abstract-no. 22 728m *
CHEMICAL ABSTRACTS, vol. 105, no. 26, December 29, 1986, Columbus, Ohio, USA NISHIIKE UJIHIRO et al. "La- mination of oriented silicon steel sheets.", page 247, column 2, abstract-no. 230 798g *
CHEMICAL ABSTRACTS, vol. 114, no. 16, April 22, 1991, Columbus, Ohio, USA TANAKA OSAMU et al. "Sup- pressing glassy film forma- tion on oriented electric steel strip for lustrous appearance and easy punching.", page 273, column 1, abstract-no. 147 984e *
PATENT ABSTRACTS OF JAPAN, unexamined applications, C field, vol. 10, no. 377, December 16, 1986, THE PATENT OFFICE JAPANESE GOVERNMENT page 62 C 392 *
PATENT ABSTRACTS OF JAPAN, unexamined applications, C field, vol. 13, no. 457, October 16, 1989, THE PATENT OFFICE JAPANESE GOVERNMENT page 36 C 644 *
PATENT ABSTRACTS OF JAPAN, unexamined applications, C field, vol. 14, no. 314, July 5, 1990, THE PATENT OFFICE JAPANESE GOVERNMENT page 104 C 737 *
PATENT ABSTRACTS OF JAPAN, unexamined applications, C field, vol. 15, no. 112, March 18, 1991, THE PATENT OFFICE JAPANESE GOVERNMENT page 26 C 815 *

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US5629251A (en) * 1994-05-23 1997-05-13 Kabushiki Kaisha Kaisui Kagaku Kankyujo Ceramic coating-forming agent and process for the production thereof
EP0684322A3 (en) * 1994-05-23 1996-05-22 Kaisui Kagaku Kenkyujo Kk Ceramic coating and manufacturing process.
WO1999053107A1 (de) * 1998-04-09 1999-10-21 Koenigbauer Georg Verfahren zur herstellung eines forsterit-isolationsfilms auf einer oberfläche von korn-orientierten, anisotropen elektrotechnischen stahlblechen
EP1992708A1 (en) * 2006-03-07 2008-11-19 Nippon Steel Corporation Process for producing grain-oriented magnetic steel sheet with excellent magnetic property
EP1992708A4 (en) * 2006-03-07 2012-03-21 Nippon Steel Corp PROCESS FOR THE PRODUCTION OF AN ORIENTED GRAIN MAGNETIC STEEL SHEET WITH EXCELLENT MAGNETIC PROPERTIES
EP2615184A4 (en) * 2010-09-09 2014-06-11 Nippon Steel & Sumitomo Metal Corp ORIENTED ELECTROMAGNETIC STEEL SHEET AND PROCESS FOR ITS PRODUCTION
EP2615184A1 (en) * 2010-09-09 2013-07-17 Nippon Steel & Sumitomo Metal Corporation Oriented electromagnetic steel sheet and process for production thereof
US8784995B2 (en) 2010-09-10 2014-07-22 Jfe Steel Corporation Grain oriented electrical steel sheet and method for manufacturing the same
EP2615189A4 (en) * 2010-09-10 2014-04-09 Jfe Steel Corp GRAIN ORIENTED MAGNETIC STEEL SHEET AND PROCESS FOR PRODUCING THE SAME
EP2615189A1 (en) * 2010-09-10 2013-07-17 JFE Steel Corporation Grain-oriented magnetic steel sheet and process for producing same
EP2623633A4 (en) * 2010-09-28 2017-11-01 JFE Steel Corporation Oriented electromagnetic steel plate
EP2623634A1 (en) * 2010-09-30 2013-08-07 JFE Steel Corporation Oriented electromagnetic steel plate
EP2623634A4 (en) * 2010-09-30 2015-04-15 Jfe Steel Corp ORIENTED ELECTROMAGNETIC STEEL SHEET
EP2799594A4 (en) * 2011-12-28 2015-08-26 Jfe Steel Corp DIRECTIONAL ELECTROMAGNETIC STEEL SHEET HAVING A COATING, AND METHOD FOR MANUFACTURING THE SAME
CN104884646A (zh) * 2012-12-28 2015-09-02 Posco公司 取向电工钢板及其制造方法
US10023932B2 (en) 2012-12-28 2018-07-17 Posco Grain-oriented electrical steel sheet, and method for manufacturing the same
US10793929B2 (en) 2013-07-24 2020-10-06 Posco Grain-oriented electrical steel sheet and method for manufacturing same
US11984249B2 (en) 2018-01-31 2024-05-14 Jfe Steel Corporation Grain-oriented electrical steel sheet, wound transformer core using the same, and method for producing wound core
CN113166950A (zh) * 2018-11-30 2021-07-23 Posco公司 取向电工钢板及其制造方法
CN113166950B (zh) * 2018-11-30 2023-07-14 浦项股份有限公司 取向电工钢板及其制造方法

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