EP0266422A1 - Verfahren zur herstellung von dünnen silizium-stahlblechen mit goss-textur mit niedrigen wattverlusten sowie mit ausgezeichneten oberflächeneigenschaften - Google Patents

Verfahren zur herstellung von dünnen silizium-stahlblechen mit goss-textur mit niedrigen wattverlusten sowie mit ausgezeichneten oberflächeneigenschaften Download PDF

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EP0266422A1
EP0266422A1 EP86902022A EP86902022A EP0266422A1 EP 0266422 A1 EP0266422 A1 EP 0266422A1 EP 86902022 A EP86902022 A EP 86902022A EP 86902022 A EP86902022 A EP 86902022A EP 0266422 A1 EP0266422 A1 EP 0266422A1
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annealing
steel sheet
thin sheet
subjecting
reduction
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EP0266422B2 (de
EP0266422A4 (de
EP0266422B1 (de
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Yukio Kawasaki St. Corp. Techn. Res. Di. Inokuti
Yoh Kawasaki St. Corp. Techn. Res. Div. Ito
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JFE Steel Corp
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Kawasaki Steel Corp
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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
    • C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
    • C21D8/1233—Cold rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1294—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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
    • C21D8/1227—Warm rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest

Definitions

  • the grain oriented silicon steel sheets can be utilized as a core for transformer and other electrical machinery and equipment, and are required to have a high magnetic flux density (represented by B l o value) and a low iron loss (represented by W 17 / 50 value).
  • Japanese Patent Application Publication No. 57-2,252 Japanese Patent Application Publication No. 58-53,419, Japanese Patent Application Publication No. 58-5,968, Japanese Patent Application Publication No. 58-26,405, Japanese Patent Application Publication No. 58-26,406, Japanese Patent Application Publication No. 58-26,407 and Japanese Patent Application Publication No.
  • a silicon steel material having a high Si content of Si: 3.1-4.5 % is essentially a material suitable for obtaining a high magnetic flux density, low iron loss product, and found that the surface properties can be made good even at the high Si content by enriching Mo in the surface layer of the steel material before the hot rolling as a means for solving the degradation of surface properties.
  • the surface properties of the product are largely improved as compared with the former case, but if it is particularly intended to thin the gauge of the product to 0.23-0.17 mm for obtaining low iron loss, there is remaining a large problem that the improving effect of surface properties is small.
  • Japanese Patent laid open No. 59-126,722 discloses that in order to stably manufacture thinned products by utilizing AlN precipitation phase at high Si content, two-stage cold rolling process largely different from the conventional strong one-stage cold rolling process is particularly applied to a hot rolled material containing small amounts of Cu and Sn in addition to AlN.
  • This is effective for stably reducing the iron loss of the thinned product, but has yet many problems that it is difficult to obtain products having excellent surface properties because the high-temperature heating of slab is usually required under a state of increasing Si and that the cost of the product becomes considerably higher because the small amounts of Sn and Cu are added for stabilizing secondary recrystallized grains.
  • the hot brittleness becomes conspicuous, and the hot tear is caused in the slab heating or hot rolling to considerably degrade, the surface properties of the product as previously mentioned.
  • the development on the improvement of steel sheet purity 3 or orientation 4 is considered to be extreme at the present.
  • the Goss orientation of secondary recrystallized grains in the existing products is aligned within 3°-4° on average with respect to the rolling direction, so that it is very difficult in metallurgy to make the crystal grain small under such a highly aligned state.
  • a method of producing a low iron loss grain oriented silicon steel thin sheet having excellent surface properties which comprises subjecting a steel slab containing
  • a method of producing a low iron loss grain oriented silicon steel thin sheet having excellent surface properties which comprises subjecting a steel slab containing
  • a method of producing a low iron loss, high magnetic flux density grain oriented silicon steel thin sheet having excellent surface properties which comprises subjecting a steel slab containing
  • a method of producing a low iron loss, high magnetic flux density grain oriented silicon steel thin sheet having excellent surface properties which comprises subjecting a steel slab containing
  • a method of producing a low iron low grain oriented silicon steel thin sheet having excellent surface properties which comprises subjecting a steel slab containing
  • a method of producing a low iron loss grain oriented silicon steel thin sheet having excellent surface properties which comprises subjecting a steel slab containing
  • the intermediate annealing in each of the above inventions is carried out by heating or cooling at a rate of 5°C per second over a range of 500 ⁇ 900°C at the temperature rising or temperature dropping stage.
  • the inventors have found that when a grain oriented silicon steel thin sheet is produced by utilizing A2N precipitation phase at a high silicon content of 3.1-4.5 wt%, products having excellent surface properties are obtained by adding a small amount of Mo to a steel material and also the production of grain oriented silicon steel sheets having a low iron loss is made possible at very stable steps by the adoption of two-stage cold rolling process including an intermediate annealing of rapid heating ⁇ rapid cooling, and as a result each of the above inventions has been accomplished.
  • the hot rolled steel sheet was subjected to a primary cold rolling at a reduction of not more than 70% and further to an intermediate annealing at 1,050°C for 3 minutes.
  • the intermediate annealing the temperature rising from 500°C to 900°C was carried out by rapid heating treatment of 10°C/s, and the temperature dropping from 900°C to 500°C was carried out by rapid cooling treatment of 15°C/s.
  • the steel sheet was subjected to a secondary cold rolling at a reduction of 70%-91% to obtain a cold rolled steel sheet having a final gauge of 0.20 mm, which was then subjected to decarburization and primary recrystallization annealing at 850°C in a wet hydrogen atmosphere.
  • an annealing separator mainly composed of MgO was applied to the surface of the steel sheet, which was subjected to a secondary recrystallization annealing by raising temperature between 850°C ⁇ 1, 100°C at 8°C/hr and further to a high-temperature finish annealing or a purification annealing in a dry hydrogen atmosphere at 1,200°C for 10 hours.
  • Fig. 1 The magnetic properties of the resulting product and the ratio of surface defect produced (a ratio of surface defect block existing on the steel sheet surface is represented by %) are shown in Fig. 1.
  • the product made from the test steel I containing Mo is good in the magnetic properties when the reduction at primary cold rolling is 10-60% (particularly 20-40%), and the ratio of surface defect produced in the product is noticed to be not more than 2% (not more than 0.5 % when the reduction at primary cold rolling is within a range of 20-25%).
  • the Bio value and W 17/50 value are somewhat poorer than those of the test steel I as magnetic properties as seen from plots shown by mark 0 in the same figure, and particularly the ratio of surface defect produced in the product is as extremely high as 6 ⁇ 18%.
  • the hot rolled steel sheet was subjected to a primary cold rolling at a reduction of about 40% and further to an intermediate annealing at 1,050°C for 3 minutes.
  • the intermediate annealing each of the temperature rising rate from 500°C to 900°C and the cooling rate from 900°C to 500°C was varied within a range of 1°C-100°C.
  • the steel sheet after the intermediate annealing was subjected to a secondary cold rolling at a reduction of about 83% to obtain a cold rolled steel sheet having a final gauge of 0.23 mm, which was then subjected to decarburization and primary recrystallization annealing at 850°C in a wet hydrogen atmosphere, an application of an annealing separator mainly composed of MgO onto steel sheet surface, a secondary recrystallization annealing by raising temperature from 850°C to 1,100°C at 10°C/hr, and a purification annealing in a dry hydrogen atmosphere at 1,200°C for 10 hours.
  • the magnetic properties of the resulting product are shown in Fig. 2.
  • products having considerably improved magnetic properties can be obtained when the temperature rising rate from 500°C to 900°C at the intermediate annealing and the cooling rate from 900°C to 500°C after the intermediate annealing are not less than 5°C/s, particularly not less than 10°C/s.
  • 59-126,722 applies only AeN micro-precipitation treatment through quenching treatment after normalized annealing in the conventional strong one-stage cold rolling process to the cooling stage of the intermediate annealing after the primary cold rolling, while according to the invention it is newly elucidated that excellent magnetic properties are obtained only by the combination of rapid cooling at the intermediate annealing with rapid heating at the temperature rising stage of the intermediate annealing and particularly the addition of Mo.
  • test steel A containing C: 0.046 wt%, Si: 3.36 wt%, Mo: 0.026 wt%, Sb: 0.025 wt%, acid soluble A2: 0.024 wt% and Se: 0.020 wt%
  • the hot rolled steel sheet was subjected to a normalized annealing at 1,050°C for 2 minutes and quenched.
  • the steel sheet was subjected to a primary cold rolling at a reduction of about 40% and further to an intermediate annealing at 1,000°C for 2 minutes.
  • the temperature rising from 500°C to 900°C was carried out by rapid heating treatment of 10°C/s
  • the temperature dropping from 900°C to 500°C was carried out by rapid cooling treatment of l2°C/s.
  • the steel sheet was subjected to a secondary cold rolling at a reduction of 85% to obtain a cold rolled steel sheet having a final gauge of 0.20 mm, which was subjected to decarburization and primary recrystallization annealing at 830°C in a wet hydrogen atmosphere.
  • the steel sheet After an annealing separator mainly composed of MgO is applied to the steel sheet surface, the steel sheet was subjected to a secondary recrystallization annealing by raising temperature from 850°C at a rate of 10°C/hr, a purification annealing in a dry hydrogen atmosphere at 1,200°C for 10 hours, a baking treatment with an insulation coating and a strain relief annealing at 800°C for 3 hours.
  • the magnetic properties of the product made from the test steel A containing Mo therein are good that the B 10 value is 1.94 T and the W 17/50 value is 0.82 W/kg, and it is noted that the ratio of surface defect produced in the product is 1.8%.
  • the magnetic properties of the product made from the comparative steel B of the conventional composition are bad that B 10 is 1.93 T and W 17 / 50 is 0.85 W/kg as compared with those of the test steel B containing Mo therein, and particularly the ratio of surface defect produced in the product is as extremely high as 8%.
  • the hot rolled steel sheet was subjected to a primary cold rolling at a reduction of not more than 70 % and further to an intermediate annealing at 1,100°C for 3 minutes.
  • the temperature rising from 500°C to 900°C was carried out by rapid heating treatment at a heating rate of 13°C/s, and the temperature dropping from 900°C to 500°C after the intermediate annealing was carried out by rapid cooling treatment at a cooling rate of 18°C/s.
  • the steel sheet was then subjected to a secondary cold rolling at a reduction of 70%-91% to obtain a cold rolled steel sheet having a final gauge of 0.20 mm.
  • a warm rolling at 250°C was carried out in the course of the cold rolling.
  • each of these samples was subjected to decarburization and primary recrystallization annealing in a wet hydrogen atmosphere, and after an annealing separator mainly composed of MgO was applied to the steel sheet surface, the sample was further subjected to a secondary recrystallization.annealing by raising temperature from 850°C to 1,100°C at 10°C/hr and a purification annealing in a dry hydrogen atmosphere at 1,200°C for 10 hours.
  • the test steels III containing Mo therein have good magnetic properties when the reduction at primary cold rolling is from 10 to 60% (particularly 20-40 % ), and it is noted that the ratio of surface defect produced in the product is not more than 3% (particularly not more than 1.0% when the reduction at primary cold rolling is within a range of 20-50 % ).
  • the properties of the comparative steels II of the conventional composition mark A, ⁇
  • B 10 value and W 17/50 value are somewhat poorer than those of Mo containing steel, and the ratio of surface defect produced in the product is as extremely high as 6-20%.
  • the magnetic properties are considerably good that W 17/50 value is 0.72 W/kg when the reduction at primary cold rolling is 30-40 % (reduction at secondary cold rolling, 87-85%) as shown in plots of mark B of the test steel III, and the ratio of surface defect produced in the product is as good as not more than 1%.
  • the W 17/50 value of iron loss is as good as 0.75 W/kg when the reduction at primary cold rolling is 30-40% as shown in plots of mark A, but the ratio of surface defect produced in the product is as high as 6-7 % .
  • the hot rolled steel sheet was subjected to two-stage cold rolling (reduction at primary cold rolling: 50 % , reduction at secondary cold rolling: 80%) through an intermediate annealing at 980°C for 3 minutes to obtain a cold rolled steel sheet having a final gauge of 0.20 mm.
  • the temperature rising from 500°C to 900°C was carried out by rapid heating treatment at a heating rate of 10°C/s, and the temperature dropping from 900°C to 500°C after the intermediate annealing was carried out at a cooling rate of 13°C/s.
  • the steel sheet was subjected to a secondary recrystallization annealing by raising temperature from 850°C to 1,050°C at 10°C/hr, a purification treatment at 1,200°C for 8 hours, a baking treatment with an insulation coating and a strain relief annealing at 800°C for 3 hours.
  • the grain oriented silicon steel sheet was produced by a method of applying an annealing separator mainly composed of MgO with omitting the adhesion treatment of Al 2 O 3 powder according to the usual manner, which was a comparative example.
  • the magnetic properties of the product made from the test steel C containing Mo therein are good that B 10 is 1.94 T and W 17/50 is 0.84 W/kg when the MgO annealing separator is uniformly applied to the steel sheet according to the usual manner after the decarburization and primary recrystallization annealing, and the ratio of surface defect produced in the product is 0.4%.
  • the-magnetic properties of the product made from the comparative steel D of the conventional composition are B 10 of 1.93 T and W 17/50 of 0.86-0.90 W/kg depending upon the handling conditions after the decarburization and primary recrystallization annealing and are poorer than those of the test steel C containing Mo therein, and the ratio of surface defect produced in the product is as extremely high as 9-10 % .
  • test steel E containing C: 0.053 % , Si: 3.43%, Mo: 0.026 % , acid soluble Al: 0.029%, Se: 0.021% and Sb: 0.020%
  • steel ingot (test steel F) containing C: 0.058%, Si: 3.49%, acid soluble A2: 0.026%, S: 0.026 % , Cu: 0.1% and Sn: 0.05% was heated at 1,420°C for 5 hours to perform the dissociation-solution of inhibitor and hot rolled to form a hot rolled steel sheet of 2.0 mm in thickness.
  • the hot rolled-steel sheet was subjected to a normalized annealing at 1,080°C for 2 minutes, quenched and subjected to two-stage cold rolling (reduction at primary cold rolling: 50%, reduction at secondary cold rolling: 80 % ) through an intermediate annealing at 950°C for 3 minutes to obtain a cold rolled steel sheet having a final gauge of 0.20 mm.
  • the temperature rising from 500°C to 900°C was carried out by rapid heating treatment at 11°C/s, and the temperature dropping from 900°C to 500°C after the intermediate annealing was carried out at a cooling rate of 12°C/s.
  • the steel sheet was coated at its surface with an annealing separator mainly composed of MgO, and subjected to a secondary recrystallization annealing by raising temperature from 850°C to 1,050°C at a heating rate of 12°C/hr and further to a purification annealing in a dry hydrogen atmosphere at 1,220°C for 5 hours.
  • an annealing separator mainly composed of MgO
  • the steel sheet after the finish annealing was subjected to the baking treatment with the insulation coating and further to a strain relief annealing at 800°C for 3 hours.
  • the magnetic properties of the product made from the test steel E containing Mo therein are good as B 10 of 1.94 T and W 17/50 of 0.84 W/kg when the insulation coating is formed according to the usual manner after the finish annealing, and the ratio of surface defect produced in the product is 0.2%.
  • the magnetic properties are very good as Bio of 1.94 T and W 17/50 of 0.76 W/kg, and it is noted that the ratio of surface defect produced in the product is 0.4%.
  • the magnetic properties of the product made from the comparative steel F of the conventional composition are B 10 of 1.93 T and W 17/50 of 0.85-0.90 W/kg depending upon the handling conditions after the finish annealing and are poorer than those of the test steel E containing Mo therein, and the ratio of surface defect produced in the product is as extremely high as 9-11%.
  • a part of the constructions of the above method is a method wherein iron loss is reduced by irradiating a laser to the surface of the grain oriented silicon steel sheet after the finish annealing in a direction substantially perpendicular to the rolling direction to introduce artificial grain boundary thereinto as disclosed in Japanese Patent Application Publication No. 57-2,252, Japanese Patent Application Publication No. 57-53,419, Japanese Patent Application Publication No. 58-5,968, Japanese Patent Application Publication No. 58-26,405, Japanese Patent Application Publication No. 58-26,406, Japanese Patent Application Publication No. 58-26,407 and Japanese Patent Application Publication No. 58-36,051.
  • the low iron loss grain oriented silicon steel sheet can advantageously be produced by a method wherein-microstrain is introduced through laser irradiation, and a base metal is completely exposed through pickling to react with Sb at a high temperature, and recovery-recrystallization of local areas is accelerated to form heterogeneous microareas onto the steel sheet surface.
  • the latter method is an epock-making method that the degradation of iron loss is not caused even when being subjected to high-temperature heating treatment, which is different from the laser irradiated product sheet as mentioned above, and a part of the constructions of this method is disclosed in Japanese Patent laid open No. 60-255,926.
  • the invention makes possible to produce grain oriented silicon steel sheets having good iron loss and surface properties at stable steps by the addition of Mo to steel material, adoption of two-stage cold rolling process, preferably restriction of temperature rising-temperature dropping rates at the intermediate annealing, and further formation of heterogeneous microareas onto the steel sheet in the decarburization and primary recrystallization annealing or after the finish annealing, which is different from the aforementioned conventional techniques in the fundamental idea and is fairly superior in the effect obtained by the adoption of these steps as compared with the conventional techniques...
  • Si is an element effective for increasing the electrical resistance of silicon steel sheet to reduce eddy current loss as previously mentioned, and is particularly required to be not less than 3.1 wt% for reducing the iron loss of the thinned product.
  • Si amount exceeds 4.5 wt%, the brittle fracture is apt to be caused in the cold rolling, so that the Si amount is limited to a range of 3.1-4.5 wt%.
  • the Si amount in the conventional grain oriented silicon steel sheet utilizing AlN as an inhibitor is about 2.8-3.0 wt%, but if the Si amount is increased, the surface properties of product as in the comparative steels I, III of Figs. 1, 3 are considerably degraded.
  • the prevention on the occurrence of surface defects is made possible by adding 0.003-0.1 wt% of Mo to the steel material.
  • the amount of Mo added to the steel material is less than 0.003 wt%, the force improving the magnetic properties and preventing the occurrence of surface defect is weak, while when it exceeds 0.1 % , the decarburization in steel is delayed at the decarburization step, so that the amount should be limited to a range of 0.003-0.1 wt%.
  • Al forms a fine precipitate of AlN by bonding to N contained in steel and acts as a strong inhibitor.
  • acid soluble At is necessary to be within a range of 0.005-0.06 wt%.
  • the amount of acid soluble At is less than 0.005 wt%, the precipitated amount of AlN fine precipitates as an inhibitor is lacking and the growth of secondary recrystallized grains in ⁇ l10 ⁇ 001> orientation is insufficient, while when it exceeds 0.06 wt%, the growth of secondary recrystallized grains in ⁇ 110 ⁇ 001> orientation is also considerably degraded.
  • S and Se form dispersed precipitation phases of MnS or MnSe together with A2N to promote the inhibitor effect. If the amount of S or Se in total is less than 0.005 wt%, the inhibitor effect of MnS or MnSe is weak, while when the total amount exceeds 0.1 wt%, the hot and cold workabilities are considerably degraded, so that the amount of at least one of S, Se in total should be within a range of 0.005-0.1 wt%.
  • the S amount is less than 0.005 wt%, or if the Se amount is less than 0.003 wt%, the inhibitor effect is lacking, while if each of the amounts exceeds 0.05 wt%, the hot and cold workabilities are degraded, so that it is desirable that the S amount is within a range of 0.005-0.05 wt% and the Se amount is within a range of 0.003-0.05 wt%.
  • Sb functions the control of primary recrystallized grain growth.
  • the amount is less than 0.005 wt % , the effect is small, while when it exceeds 0.2 wt % , the magnetic flux density is lowered to reduce the magnetic properties, so that the amount should be within a range of 0.005-0.2 wt%.
  • C is required to produce r transformation in a part of the steel sheet during the annealing of the hot rolled steel sheet in connection with the fine precipitation of AiN.
  • the C amount is suitable within a range of about 0.030-0.080 wt% when the Si amount is within a range of 3.1 ⁇ 4.5 wt% according to the invention.
  • At least one of Sn, Cu and B added to ordinary silicon steel as a well-known inhibitor for primary recrystallized grain growth may be contained in a total amount of not more than 0.5 wt%, and also it is generally accepted to contain a slight amount of inevitable elements such as Cr, Ti, V, Zr, Nb, Ta, Co, Ni, P, As and so on.
  • LD converter open hearth and other well-known steel making processes can be used as a means for melting the steel material used in the method according to the invention. It is a matter of course that the above means may be used together with vacuum treatment or vacuum dissolution.
  • the usual ingot making-bloom rolling as well as continuous casting may preferably be used.
  • the thus obtained silicon steel slab is heated in the well-known method and then subjected to a hot rolling.
  • the thickness before hot rolling obtained by the hot rolling is different by the reduction of the subsequent cold rolling step, but it is usually desirable to be about l.5 ⁇ 3.0 mm.
  • the addition of a small amount of Mo to the steel material is an essential feature for obtaining silicon steel sheets having good surface properties.
  • a means for enriching Mo in the surface layer of the steel sheet by applying Mo compound to the surface up to the completion of the hot rolling may naturally be used.
  • the hot rolled steel sheet after the completion of the hot rolling is subjected to a primary cold rolling.
  • the steel sheet is subjected to a normalized annealing within a temperature range of 900 ⁇ 1, 200°C and a quenching treatment for obtaining finely uniformized dispersion of C into the hot rolled steel sheet before the primary cold rolling.
  • the reduction at primary cold rolling is somewhat different in accordance with the gauge of the product, but it is limited to 10-60 % (desirably 20-50%) for obtaining the thinned product having good properties according to the invention as seen from Figs. 1 and 3.
  • the intermediate annealing is carried out at a temperature of 900-1,100°C for about 30 seconds-30 minutes.
  • the temperature rising from 500°C to 900°C and the temperature dropping from 900°C to 500°C after the intermediate annealing are carried out at a rate of not less than 5°C/s, preferably not less than 10°C/s.
  • Such rapid heating and rapid cooling treatments may be performed by a well-known means such as a continuous furnace, a batch furnace or the like.
  • the secondary cold rolling is adapted at a reduction of 75-90 % as seen from Figs. 1 and 3, whereby a cold rolled steel sheet having a final gauge of 0.1-0.25 mm is finished.
  • Each of the inventions is to produce high magnetic flux density electromagnetic steel thin sheets.
  • the steel sheets having good properties are obtained by finishing the hot rolled steel sheet of about 1.5-3.0 mm in thickness at the reduction of each of the cold rolling and secondary cold rolling shown in Figs. 1 and 3 into a cold rolled steel thin sheet having a final gauge of 0.1 ⁇ 0.25 mm.
  • an ageing treatment at 50 ⁇ 600°C may be performed through plural passes as disclosed in Japanese Patent Application Publication No. 54-13,866.
  • the thus cold rolled thin sheet of 0.1-0.25 mm in gauge is subjected to a decarburization annealing serving as a primary recrystallization within a temperature range of about 750 ⁇ 870°C.
  • the decarburization annealing may be usually performed in a wet hydrogen atmosphere having a dew point + about 30 ⁇ 65°C or in a mixed gas atmosphere of hydrogen ⁇ nitrogen for several minutes.
  • the steel sheet after the decarburization annealing is coated with an annealing separator mainly composed of MgO and subjected to a finish annealing to grow secondary recrystallized grains in ⁇ 110 ⁇ 001> orientation.
  • the concrete conditions for the finish annealing may be the same as in the well-known ones, but it is usually desirable that the secondary recrystallized grains are grown by raising temperature up to 1,150-1,250°C at a temperature rising rate of 3-50°C/hr and then a purification annealing is carried out in a dry hydrogen atmosphere for 5-20 hours.
  • a treatment for forming heterogeneous microareas onto the steel sheet surface through subsequent high-temperature finish annealing is previously performed in the decarburization and primary recrystallization annealing, i.e. before or after this annealing treatment and then the high-temperature finish annealing is performed as previously mentioned in the third and fourth inventions, or the laser irradiation is performed as mentioned in the fifth and sixth inventions, whereby low iron loss grain oriented silicon steel sheets can be produced.
  • the treatment for the formation of heterogeneous microareas can use the following methods:
  • the decarburization promotion area and decarburization delay area are alternately formed on the steel sheet surface at substantially an equal width every an interval of 1-50 mm as previously disclosed in Japanese Patent laid open No. 60-39,124.
  • the narrower the width of these areas the finer the primary recrystallized texture, and hence the secondary recrystallized grain becomes finer.
  • the secondary recrystallized grain size of the product is usually within a range of 1.5-25 mm, when the primary recrystallized texture is varied on the steel sheet surface at a width corresponding to not more than 2 times of the secondary recrystallized grain size or a width of 3-50 mm, it is possible to obtain finer secondary recrystallized grains.
  • the effect of applying the coating agent to the steel sheet surface is sufficiently developed even at the one-side surface, but it is more enhanced when being applied to both-side surfaces of the steel sheet.
  • As the application method to the steel sheet surface it is considered that the application with a grooved or uneven rubber roll is optimum, but a spraying method after the covering of unnecessary area with a masking plate may be used.
  • the coating solution for forming the decarburization promotion area and decarburization delay area on the steel sheet surface may be prepared according to the teaching published by the inventors (Y.Inokuti: Trans. ISIJ, Vol.- 15 (1975), P.324), which is quoted below by way of precaution.
  • Decarburization promotion agent MgCl 2 ⁇ 6H 2 O, Mg(NOg) 2 -6H 2 O, CaCe 2 -2H 2 O, Ca(NO 3 ) 2 -4H 2 O, SrCl 2 -2H 2 O, Sr(NO 3 ) 2 -4H 2 O, BaCl 2 -2H 2 O, Ba(N0 3 ) 2 , KCl, KMn0 4 , K 2 P 2 O 7 , KBr, KClO 3 , KBr0 3 , KF, NaCl, NaI0 4 , NaOH, NaHP0 4 , NaH 2 PO 4 -2H 2 O, NaF, NaHCO 3 -Na 2 O 5 , Na 4 P 2 O 7 -10H 2 O, NaI-(NH 4 ) 2 Cr 2 O 7 , Cu(NO 3 ) 2 -3H 2 O, Fe(NO 3 ) 3 -9H 2 O, Co(N0 3 ) 2 -6H 2 0, Ni(NO
  • Decarburization delay agent K 2 S, Na 2S2 O 3 ⁇ 5H 2 O, Na 2 S ⁇ 9H 2 O, MgS0 4 , SrS0 4 , Al 2 (SO 4 ) 3 ⁇ 18H 2 O, S 2 Cl 2 , NaHS0 3 , FeSO 4 ⁇ 7H 2 O, KHS0 4 , Na 2 S 2 O 8 , K 2 S 2 O 7 , Ti(S0 4 ) 2 ⁇ 3H 2 O, CuSO 4 ⁇ 5H 2 O, ZnSO 4 ⁇ 7H 2 O, CrSO 4 ⁇ 7H 2 O, (NH 4 ) 2 S 2 O 8 , H 2 S0 4 , H 2 Se0 3 , Se O Cl 2 , Se 2 Cl 2 , Se0 2 , H 2 Se0 4 , K 2 Se, Na2Se, Na 2 SeO 3 , K 2 Se0 3 , Na 2 SeO 4 , K 2 Se0 4 , H 2 TeO 4 ⁇ 2H 2 O, Na 2 Te0
  • the non-treated area is formed as a delay area in the treatment using only the former agent or as a promotion area in the treatment using only the latter agent.
  • the method of forming the microareas on the steel sheet surface after the decarburization and primary recrystallization annealing with a secondary recrystallization promoting or controlling agent may be performed according to the teaching of Japanese Patent laid open No. 60-89,521, which is quoted below by way of precaution.
  • YAG laser-pulse generating multimode is optimum.
  • the preferable irradiation conditions of laser treatment for steel sheet surface are
  • the method 3 i.e. the formation of temperature difference on the steel sheet-surface through heat treatment may be performed according to the teachings of the well-known articles (Japanese Patent laid open No. 60-103,132 and the like). By way of precaution, the preferred conditions are mentioned as follows.
  • the method for ununiform heat treatment through these repeated annealing treatments may be performed by any one of conventional well-known means such as local heating with flash lamp, infrared ray lamp, high frequency induction heating, pulse type heat treatment and so on.
  • the annealing separator mainly composed of MgO is applied to the treated steel sheet surface and then the high-temperature finish annealing is performed to grow the secondary recrystallized grains strongly aligned in ⁇ 110 ⁇ 001> orientation.
  • the concrete conditions of the finish annealing may be the same as in the conventional well-known annealing method, but it is usually desirable that the temperature is raised up to 1,150-1,2500C at a temperature rising rate of 3-50°C/hr to grow the secondary recrystallized grains and then a purification annealing is carried out in a dry hydrogen atmosphere for 5-20 hr..
  • the method may be performed according to the method previously disclosed in Japanese Patent laid open No. 60-92,479. By way of precaution, there are mentioned the following four methods:
  • oxides such as Si0 2 , Al 2 O 3 , Zr0 2 and so on as well as metals such as Zn, Al, Sn, Ni, Fe and so on are mentioned.as a reaction inhibiting substance.
  • the amount of the reaction inhibiting substance adhered exceeds 1 g/m 2 , the reaction inhibiting effect becomes excessive and the forsterite layer is not formed. Therefore,it is necessary to control the amount of forsterite layer thickness reduced by limiting the amount of the reaction inhibiting substance to not more than 1 g/m 2 .
  • anyone of application, spraying, plating, printing, static painting and the like may be utilized as a means for adhering the reaction inhibiting substance to the steel sheet.
  • the water repellent substance oil paint, varnish and the like are advantageously adaptable.
  • This substance inhibits the contact between the steel sheet surface and the annealing separator to delay the reaction of forsterite formation and form the reduced area of forsterite thickness.
  • the amount of the substance adhered exceeds 0.1 g/m 2 , the reaction delaying effect becomes excessive to form no forsterite layer, so that it is necessary to control the reduced amount of forsterite layer thickness by limiting the amount of the substance to not more than 0.1 g/m2.
  • the application, spraying, printing, static painting and the like may be used likewise the case of using the aforementioned reaction inhibiting substance.
  • This substance oxidises Si in steel at high temperature in the subsequent finish annealing to increase the amount of Si0 2 grains in subscale of steel sheet surface, whereby the thickness of forsterite layer after the finish annealing is increased to locally form the thickness increased layer on the steel sheet surface.
  • oxides such as FeO, Fe 2 0 3 , Ti0 2 and so on, reducible silicates such as Fe 2 Si0 4 and so on, hydroxides such as Mg(OH) 2 and so on are advantageously adaptable.
  • the amount of the oxidizer adhered exceeds 2 g/m 2 , the layer thickness becomes too thick to lose the adhesion force to the steel sheet and peel off the layer, and consequently the given object can not be achieved.
  • the thermal expansion coefficient of the insulation coating is not more than 8.5x10 -6 1/°C and the coefficient between different coatings is not less than 1.1 as disclosed in Japanese Patent laid open No. 60-103,182, which may be achieved by alternately applying and baking the conventionally known different coating solutions at an interval of 1-30 mm.
  • the steel sheet layer is peeled off from the steel sheet surface after the finish annealing by means of a laser or a means for application of stress such as scriber, and a part of the base metal is removed with an acid such as hydrochloric acid, nitric acid or the like, and then the treated steel sheet is immersed in an aqueous solution of an inorganic compound containing a semi-metal, a metal or the like to fill in the removed portion, which is thereafter subjected to recovery ⁇ recrystallization annealing serving as a strain relief annealing to form ununiform areas.
  • an insulation coating composed mainly of phosphate and colloidal silica is applied and baked to the above treated sheet. It is naturally required for use in transformers having a capacity as large as 1,000,000 KVA.
  • the formation of such an insulation coating may be performed by using the conventionally well-known process as it is.
  • the strain relief annealing is carried out at a temperature of not lower than 600°C.
  • the method according to the invention has a characteristic that the degradation of magnetic properties is not caused even after such a high-temperature annealing.
  • a continuously cast slab containing C: 0.059%, Si: 3.49 % , Mo: 0.024 % , acid soluble Al: 0.034 % , S: 0.029% was heated at 1,430°C for 3 hours and hot rolled to form a hot rolled steel sheet of 2.2 mm in thickness. Thereafter, the steel sheet was subjected to a primary cold rolling at a reduction of about 50 % and further to an intermediate annealing at 1,100°C for 3 minutes. -In the intermediate annealing, rapid heating treatment of 12°C/s was performed from 500°C to 900°C, and rapid cooling treatment of 15°C/s was performed from 900°C to 500°C after the intermediate annealing.
  • the steel sheet was subjected to a cold rolling at a reduction of about 80 % to obtain a cold rolled steel sheet having a final gauge of 0.20 mm, which was then subjected to a primary recrystallization annealing serving as a decarburization in a wet hydrogen atmosphere at 830°C.
  • the magnetic properties were Bio:1.93 T and W 17/50 :0.80 w/kg, and the surface properties were very good as the ratio of surface defect block produced was 0.8%.
  • a continuously cast slab containing C: 0.064%, Si: 3.39 % , Mo: 0.019%, acid soluble A8: 0.029%, Se: 0.020%, Sb: 0.022 % was heated at 1,420°C for 4 hours and hot rolled to a thickness of 2.2 mm. Thereafter, the steel sheet was subjected to a primary cold rolling at a reduction of about 40 % and further to an intermediate annealing at 1,100°C for 2 minutes. In the intermediate annealing, rapid heating treatment of 12°C/s was performed from 500°C to 900°C, and rapid cooling treatment of 18°C/s was performed from 900°C to 500°C after the intermediate annealing.
  • the steel sheet was subjected to a secondary cold rolling at a reduction of about 83% to obtain a cold rolled steel sheet having a final gauge of 0.23 mm, which was then subjected to decarburization and primary recrystallization annealing in a wet hydrogen atmosphere at 840°C.
  • a secondary recrystallization was performed by raising temperature from 850°C to 1,100°C at 10°C/hr, and then a purification annealing was performed in a dry hydrogen atmosphere at 1,200°C for 15 hours.
  • the magnetic properties and surface properties of the resulting product were as follows.
  • the magnetic properties were B 10 :1.93 T and W 17/50 :0.80 w/kg, and the surface properties were very good as the ratio of surface defect block produced was 0.6%.
  • a steel ingot containing C: 0.058%, Si: 3.59%, Mo: 0.035%, acid soluble At: -0.033%, S: 0.023%, Cu: 0.15%, Sn: 0.11% was hot rolled to form a hot rolled steel sheet of 2.0 mm in thickness, which was then subjected to a primary cold rolling (reduction: about 40%). Thereafter, the steel sheet was subjected to an intermediate annealing at 1,050°C for 5 minutes, wherein the temperature rising from 500°C to 900° C was performed by rapid heating treatment of 18°C/s and the temperature dropping from 900°C to 500°C was performed by rapid cooling treatment of 20°C/s.
  • the steel sheet was subjected to a strong cold rolling at a reduction of about 89% to obtain a cold rolled steel sheet having a final gauge of 0.17 mm, during which a warm rolling at 300°C was performed. Then, the steel sheet was subjected to decarburization and primary recrystallization annealing in a wet hydrogen atmosphere at 840°C, a secondary recrystallization by raising temperature from 850°C to 1,100°C at 1 5 ° C/ hr, and a purification annealing in a dry hydrogen atmosphere at 1,200°C for 15 hours.
  • the magnetic properties were B 10 :1.93 T and W 17/50 :0.76 w/kg, and the surface properties were good as the ratio of surface defect block produced was 0.9 % .
  • a continuously cast slab containing C: 0.064%, Si: 3.45%, Mo: 0.025 % , acid soluble A2: 0.025%, S: 0.028 % was heated at 1420°C for 4 hours and hot rolled to form a hot rolled steel sheet of 2.2 mm in thickness. Then, the steel sheet was subjected to a primary cold rolling at a reduction of about 30% and further to an intermediate annealing at 1,080°C for 3 minutes. In the intermediate annealing, rapid heating treatment of 13°C/s was performed from 500°C to 900°C, and rapid cooling treatment of 18°C/s was performed from 900°C to 500°C.
  • the steel sheet was subjected to a cold rolling at a reduction of about 85% to obtain a cold rolled steel sheet having a final gauge of 0.23 mm.
  • an aqueous diluted solution of MgS0 4 (0.01 mol/l) at 85°C was applied by spraying with a jig of 0.5 mm in width at an interval of 5 mm in a direction substantially perpendicular to the rolling direction to alternately form the applied areas and non-applied areas, which was then subjected to decarburization and primary recrystallization annealing in a wet hydrogen atmosphere at 840°C.
  • the steel sheet was slowly heated from 850°C to 1,100°C at 10°C/hr and then subjected to a purification annealing in a hydrogen atmosphere at 1,200°C for 10 hours.
  • the magnetic properties and surface properties of the resulting product were as follows.
  • the magnetic properties were B 10 :1.93 T and W 17/50 :0.82 w/kg, and the surface properties were very good as the ratio of surface defect block produced was 1.2 % .
  • a continuously cast slab containing C: 0.066 % , Si: 3.5%, Mo: 0.035%, acid soluble Al: 0.030%, S: 0.02 6% , Sb: 0.026%, Sn: 0.1%, Cu: 0.1% was heated at 1,430°C for 4 hours and hot rolled to form a hot rolled steel sheet of 2.2 mm in thickness. Then, the steel sheet was subjected to a primary cold rolling at a reduction of about 40% and further to an intermediate annealing at 1,050°C for 5 minutes. In the intermediate annealing, rapid heating treatment of 15°C/s was performed from 500°C to 900°C, and rapid cooling treatment of 20°C/s was performed from 900°C to 5 00°C after the intermediate annealing.
  • the steel sheet was subjected to a cold rolling at a reduction of about 85 % to obtain a cold rolled steel sheet having a final gauge of 0.20 mm, during which a warm rolling at 250°C was performed.
  • the steel sheet was slowly heated from 850°C to 1,100°C at 8°C/hr and subjected to a purification annealing in a hydrogen atmosphere at 1,200°C for 10 hours.
  • the magnetic properties and surface properties of the resulting product were as follows.
  • the magnetic properties were B IO :1.94 T and W17/50:0.73 w/kg, and the surface properties were very good as the ratio of surface defect block produced was 1.2%.
  • a continuously cast slab containing C: 0.058 % , Si: 3.40 % , Mo: 0.026%, Se: 0.021 % , acid soluble A2: 0.030 % , Sb: 0.025 % was heated at 1,430°C for 3 hours and hot rolled to form a hot rolled steel sheet of 2.2 mm in thickness. Then, the steel sheet was subjected to a primary cold rolling at a reduction of about 50 % and further to an intermediate annealing at 1,100°C for 3 minutes. In the intermediate annealing, rapid heating treatment of 12°C/s was performed from 500°C to 900°C, and rapid cooling treatment of 15°C/s was performed from 900°C to 500°C after the intermediate annealing.
  • the steel sheet was subjected to a cold rolling at a reduction of about 80% to obtain a cold rolled steel sheet having a final gauge of 0.20 mm, which was then subjected to a primary recrystallization annealing serving as a decarburization in a wet hydrogen atmosphere at 830°C.
  • the steel sheet was subjected to a secondary recrystallization by raising temperature from 850°C to 1,100°C at 10°C/hr and further to a purification annealing in a hydrogen atmosphere at 1,200°C for 10 hours.
  • the forsterite layer having a thickness thinner by 0.6 ⁇ m was formed on the area coated with Al 2 O 3 powder.
  • the strain relief annealing was performed at 800°C for 3 hours.
  • the magnetic properties and surface properties of the resulting product were as follows.
  • the magnetic properties were B 10 :1.94 T and W 17/50 :0.78 w/kg, and the surface properties were very good as the ratio of surface defect block produced was 0.9%.
  • a continuously cast slab containing C: 0.054 % , Si: 3.36 % , Mo: 0.024%, acid soluble Al: 0.025 % , Se: 0.020% was heated at 1,420°C for 4 hours and hot rolled to form a hot rolled steel sheet of 2.2 mm in thickness. Then, the steel sheet was subjected to a primary cold rolling at a reduction of about 40% and further to an intermediate annealing at 1,100°C for 2 minutes. In the intermediate annealing, rapid heating treatment of 12°C/s was performed from 500°C to 900°C, and rapid cooling treatment of 18°C/s was performed from 900°C to 500°C after the intermediate annealing.
  • the steel sheet was subjected to a secondary cold rolling at a reduction of about 83% to obtain a cold rolled steel sheet having a final gauge of 0.23 mm, which was then subjected to decarburization and primary recrystallization annealing in a wet hydrogen atmosphere at 840°C.
  • a pulse laser was irradiated linearly (line width: 0.3 mm) at an interval of 8 mm in a direction perpendicular to the rolling direction, and thereafter a solution of SbCl 3 (0.01 mol/l, 90°C) was applied at the laser irradiated position.
  • a secondary recrystallization was performed by raising temperature from 850°C to 1,100°C at 10°C/hr, and then a purification annealing was performed in a dry hydrogen atmosphere at 1,200°C for 15 hours.
  • the steel sheet was subjected to a strain relief annealing at 800°C for 2 hours.
  • the magnetic properties and surface properties of the resulting product were as follows.
  • the magnetic properties were Bio:1.94 T and W 17/50 :0.79 w/kg, and the surface properties were very good as the ratio of surface defect block produced was 0.8%.
  • a steel ingot containing C: 0.054%, Si: 3.49%, Mo: 0.025%, acid soluble Al: 0.030%, S: 0.022%, Cu: C 15 % , Sn: 0.10 % was hot rolled to form a hot rolled stee.. sheet of 2.0 mm in thickness, which was subjected to a primary cold rolling (reduction: about 40%). Then, the steel sheet was subjected to an intermediate annealing at 1,050°C for 5 minutes, wherein the temperature rising from 500°C to 900°C was carried out by rapid heating treatment of 18°C/s, and the temperature dropping from 900°C to 500°C after the intermediate annealing was carried out by rapid cooling treatment of 20°C/s.
  • the steel sheet was subjected to a strong cold rolling at a reduction of about 89 % to obtain a cold rolled steel sheet having a final gauge of 0.17 mm, during which a warm rolling at 300°C was performed. Then, the steel sheet was subjected to decarburization and primary recrystallization annealing in a wet hydrogen atmosphere at 840°C, before which an electron beam was scanned at a width of 0.5 mm and an interval of 12 mm in a direction perpendicular to the rolling direction to form ununiform heat areas.
  • a secondary recrystallization was performed by raising temperature from 850°C to 1,100°C at 15°C/hr, and a purification annealing was performed in a dry hydrogen atmosphere at 1,200°C for 15 hours.
  • a strain relief annealing was performed at 800°C for 5 hours.
  • the magnetic properties were Bio:1.94 T and W 17/50 :0.77 w/kg, and the surface properties were very good as the ratio of surface defect block produced was 1.2 % .
  • a continuously cast slab containing C: 0.057 % , Si: 3.35%, Mo: 0.025%, acid soluble A2: 0.020%, S e: 0.022 % , Sb: 0.023% was heated at 1,420°C for 4 hours and hot rolled to form a hot rolled steel sheet of 2.2 mm in thickness. Then, the steel sheet was subjected to a primary cold rolling at a reduction of about 30 % and further to an intermediate annealing at 1,080°C for 3 minutes. In the intermediate annealing, rapid heating treatment of 13°C/s was performed from 500°C to 900°C, and rapid cooling treatment of 18°C/s was performed from 900°C to 500°C after the intermediate annealing.
  • the steel sheet was subjected to a cold rolling at a reduction of about 85% to obtain a cold rolled steel sheet having a final gauge of 0.23 mm, which was then subjected to decarburization and primary recrystallization annealing in a wet hydrogen atmosphere at 840°C.
  • an annealing separator mainly composed of MgO the steel sheet was slowly heated from 850°C to 1,100°C at 10°C/hr and subjected to a purification annealing in a hydrogen atmosphere at 1,200°C for 10 hours.
  • the steel sheet was subjected to recovery-recrystallization annealing serving as a strain relief annealing at 800°C for 5 hours.
  • the magnetic properties and surface properties of the resulting product were as follows.
  • the magnetic properties were B IO :1.94 T and W 17/50 :0.78 w/kg, and the surface properties were very good as the ratio of surface defect block produced was 1.1%.
  • a continuously cast slab containing C: 0.056 % , Si: 3.41%, Mo: 0.025%, acid soluble Al: 0.030%, Se: 0.020 % , Sn: 0.1%, Cu: 0.1% was heated at 1,430°C for 4 hours and hot rolled to form a hot rolled steel sheet of 2.2 mm in thickness. Then, the steel sheet was subjected to a primary cold rolling at a reduction of about 40% and further to an intermediate annealing at 1,050°C for 5 minutes. In the intermediate annealing, rapid heating treatment of 15°C/s was performed from 500°C to 900°C, and rapid cooling treatment of 20°C/s was performed from 900°C to 500°C after the intermediate annealing.
  • the steel sheet was subjected to a secondary cold rolling at a reduction of about 85 % to obtain a cold rolled steel sheet of 0.20 mm in gauge, during which a warm rolling at 250°C was performed. Then, the steel sheet was subjected to decarburization and primary recrystallization annealing in a wet hydrogen atmosphere at 850°C, coated with an annealing separator mainly composed of MgO, slowly heated from 850°C to 1,100°C at 8°C/hr, and subjected to a purification annealing in a hydrogen atmosphere at 1,200°C for 10 hours.
  • an annealing separator mainly composed of MgO
  • the magnetic properties were B 10 :1.94 T and W 17 / 50 :0.76 w/kg, and the surface properties were very good as the ratio of surface defect block produced was 1.1%.
  • the invention has a remarkable effect that grain oriented silicon steel thin sheets having a low iron loss that B io value is not less than 1.92 T and W 17/50 value is not more than 0.85 W/kg (0.23 mm thickness) and very excellent surface properties can be produced industrially and stably.
  • products having excellent iron loss properties and surface properties can be produced at stable steps by including Mo and A2 into a steel material, subjecting a steel sheet to two-stage cold rolling process to obtain a final cold rolled steel sheet, and forming heterogeneous microareas onto the steel sheet surface in decarburization and primary recrystallization annealing or after finish annealing to grow ununiform and fine secondary recrystallized texture in Goss orientation.

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EP86902022A 1986-03-25 1986-03-25 Verfahren zur herstellung von dünnen silizium-stahlblechen mit goss-textur mit niedrigen wattverlusten sowie mit ausgezeichneten oberflächeneigenschaften Expired - Lifetime EP0266422B2 (de)

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PCT/JP1986/000138 WO1987005945A1 (en) 1986-03-25 1986-03-25 Process for producing low core loss, thin, unidirectional silicon steel plate having excellent surface properties

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0468819A1 (de) * 1990-07-27 1992-01-29 Kawasaki Steel Corporation Verfahren zum Herstellen von kornorientierten Siliziumstahlblechen mit verbesserter magnetischer Flussdichte
WO1998002590A1 (de) * 1996-07-12 1998-01-22 Thyssen Stahl Ag Verfahren zur herstellung von kornorientiertem elektroblech

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GB1266957A (de) * 1968-04-27 1972-03-15
FR2268868A1 (de) * 1974-04-25 1975-11-21 Nippon Steel Corp
FR2472614A1 (fr) * 1979-12-28 1981-07-03 Kawasaki Steel Co Procede pour produire des toles d'acier au silicium a grains orientes ayant une induction magnetique tres elevee et une faible perte dans le fer
EP0108575A2 (de) * 1982-11-08 1984-05-16 Armco Advanced Materials Corporation Verfahren zum örtlichen Glühen von kornorientiertem Siliciumstahl mit Goss-Textur
JPS6151803A (ja) * 1984-08-21 1986-03-14 Kawasaki Steel Corp 鉄損の低い一方向性けい素鋼板

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JPS59173218A (ja) * 1983-03-24 1984-10-01 Kawasaki Steel Corp 磁束密度が高く鉄損の低い一方向性けい素鋼板の製造方法
JPS59126722A (ja) * 1983-01-11 1984-07-21 Nippon Steel Corp 鉄損の優れた薄手高磁束密度一方向性電磁鋼板の製造方法
JP2684302B2 (ja) * 1992-10-21 1997-12-03 株式会社ニューギン パチンコ遊技機

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GB1266957A (de) * 1968-04-27 1972-03-15
FR2268868A1 (de) * 1974-04-25 1975-11-21 Nippon Steel Corp
FR2472614A1 (fr) * 1979-12-28 1981-07-03 Kawasaki Steel Co Procede pour produire des toles d'acier au silicium a grains orientes ayant une induction magnetique tres elevee et une faible perte dans le fer
EP0108575A2 (de) * 1982-11-08 1984-05-16 Armco Advanced Materials Corporation Verfahren zum örtlichen Glühen von kornorientiertem Siliciumstahl mit Goss-Textur
JPS6151803A (ja) * 1984-08-21 1986-03-14 Kawasaki Steel Corp 鉄損の低い一方向性けい素鋼板

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See also references of WO8705945A1 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0468819A1 (de) * 1990-07-27 1992-01-29 Kawasaki Steel Corporation Verfahren zum Herstellen von kornorientierten Siliziumstahlblechen mit verbesserter magnetischer Flussdichte
WO1998002590A1 (de) * 1996-07-12 1998-01-22 Thyssen Stahl Ag Verfahren zur herstellung von kornorientiertem elektroblech

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WO1987005945A1 (en) 1987-10-08
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EP0266422A4 (de) 1988-11-02
EP0266422B1 (de) 1990-11-28

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