WO2008078915A1 - Procédé de fabrication de tôles en acier magnétiques à grains orientés ayant une excellente propriété magnétique et une grande productivité - Google Patents

Procédé de fabrication de tôles en acier magnétiques à grains orientés ayant une excellente propriété magnétique et une grande productivité Download PDF

Info

Publication number
WO2008078915A1
WO2008078915A1 PCT/KR2007/006723 KR2007006723W WO2008078915A1 WO 2008078915 A1 WO2008078915 A1 WO 2008078915A1 KR 2007006723 W KR2007006723 W KR 2007006723W WO 2008078915 A1 WO2008078915 A1 WO 2008078915A1
Authority
WO
WIPO (PCT)
Prior art keywords
temperature
annealing
grain
nitriding
steel sheets
Prior art date
Application number
PCT/KR2007/006723
Other languages
English (en)
Inventor
Jong-Tae Park
Chang-Soo Kim
Hyung-Don Joo
Kyu-Seung Choi
Seong-Kyu See
Kyu-Seok Han
Jae-Kwan Kim
Jae-Soo Lim
Byeong-Goo Kim
Original Assignee
Posco
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020060134910A external-priority patent/KR100797997B1/ko
Priority claimed from KR1020070078963A external-priority patent/KR101394452B1/ko
Priority claimed from KR1020070084448A external-priority patent/KR101408230B1/ko
Application filed by Posco filed Critical Posco
Priority to CN2007800484506A priority Critical patent/CN101573458B/zh
Publication of WO2008078915A1 publication Critical patent/WO2008078915A1/fr

Links

Classifications

    • 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
    • C21D8/1244—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
    • C21D8/1255—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 with diffusion of elements, e.g. decarburising, nitriding
    • 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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur

Definitions

  • the present invention relates to a method for producing grain-oriented electrical steel sheets having excellent magnetic properties with high productivity, in which the steel sheets are used as core materials for electrical devices, such as various transformers and large generators.
  • Grain-oriented electrical steel sheets are soft magnetic materials composed of crystal grains having a so-called Goss texture, expressed by
  • Such grain-oriented electrical steel sheets show excellent magnetic properties due to a secondary recrystallized texture obtained by inhibiting the growth of primary recrystallized grains and selectively growing
  • an inhibitor hindering the normal growth of primary recrystallized grains (hereinafter, referred to as "inhibitor") is particularly important. Also, it is important in the technology for producing grain-oriented electrical steel sheets to enable grains having a stable ⁇ 110 ⁇ 001> texture, among various grains, to preferentially grow
  • secondary recrystallization in a final annealing process.
  • an artificially formed fine precipitate or segregation element is used, and in order for the growth of all primary recrystallized grains to be inhibited in the final annealing process immediately until secondary recrystallization occurs, such precipitates should be distributed in a sufficient amount and a suitable size and should be thermally stable, so that they should not be easily dissolved in temperatures as high as that experienced immediately before secondary recrystallization occurs.
  • secondary recrystallization starts to occur because such inhibitors lose their function of inhibiting the growth of primary recrystallized grains while they grow or are dissolved with an increase in temperature. At this time, the secondary recrystallization occurs in a relatively short time.
  • Inhibitors which satisfy the above-mentioned conditions, and thus are currently widely used in industrial applications, include MnS, AlN, MnSe and the like.
  • a typical previous technology for producing electrical steel sheets using only MnS, among these inhibitors is disclosed in Japanese Patent Publication No. Sho 30-3651, and the production method comprises obtaining a stable secondary recrytallized texture through two stage cold rolling with an intermediate annealing.
  • the method that uses only MnS as the inhibitor has problems in that high magnetic flux density cannot be obtained, and a high production cost is incurred, because the cold rolling is carried out two times.
  • high magnetic flux density is required, because, when products having high magnetic flux density are used as core materials, the size of electrical devices can be smaller.
  • this method comprises a series of processes, including high- temperature slab reheating, hot rolling, hot-band annealing, cold rolling, decarburization annealing and final annealing.
  • the final annealing is a process in which secondary recrystallization occurs in a state in which the sheet is wound into a coil so as to develop the ⁇ 110 ⁇ 001> texture.
  • a MgO-based annealing separator is applied on the surface of steel sheets before annealing so as to prevent the steel sheets from sticking to each other and, at the same time, to allow an oxide layer, formed on the steel sheet surface upon decarburization annealing, to react with the annealing separator, to impart insulation properties to the steel sheets.
  • the steel sheets having the ⁇ 110 ⁇ 001> texture obtained by the final annealing are finally subjected to insulation coating, thus producing final products.
  • Another example of a method of producing grain-oriented electrical steel sheets using MnSe and Sb as inhibitors is disclosed in Japanese Patent Publication No. Sho 51-13469.
  • the production method comprises a series of processes, including high-temperature slab reheating, hot rolling, hot-band annealing, first cold rolling, intermediate annealing, second cold rolling, decarburization annealing and final annealing.
  • This method has an advantage in that high magnetic flux density can be obtained, but it has problems in that, because cold rolling is carried out two times, and expensive Sb or Se is used as an inhibitor, the production cost is increased, and workability is poor because of the toxicity of these elements. In addition to the above-described problems, these methods have fundamental problems that are very serious.
  • MnS or AlN contained in a slab for grain-oriented electrical steel sheets should be dissolved by reheating at a high temperature, such that it should be made into precipitates having a suitable size and distribution during hot rolling.
  • the slab must be reheated to a high temperature.
  • the slab must be reheated at more than 1300 ° C in the method that uses MnS as an inhibitor, more than 1350 ° C in the method that uses MnS+AIN as inhibitors, and more than 1320 ° C in the method that uses MnSe+Sb as inhibitors, such that high magnetic flux density can be obtained, hi actual industrial production, the slab is reheated to a temperature of about 1400 ° C in view of the size of the slab in order to obtain uniform temperature distribution up to the inner part of the slab.
  • Nitriding methods include various methods, including nitriding steel sheets in a gas atmosphere having nitriding ability after a decarburization process, applying an annealing separator containing a compound having a nitriding ability on steel sheets, and introducing an atmosphere gas containing a gas having nitriding ability inio the central part of steel sheets during a heating period in a high-temperature annealing process.
  • the method of nitriding steel sheets in a gas atmosphere having nitriding ability after a decarburization process is most generally used.
  • a method of supplying nitrogen into steel sheets in a separate nitriding process containing ammonia gas, after decarburizing the steel sheets with Al-based nitride is disclosed in Japanese
  • nitriding with ammonia gas uses a characteristic which ammonia is decomposed into hydrogen and nitrogen at more than about 500 ° C , and the decomposed nitrogen is introduced into steel sheets.
  • the nitrogen introduced into steel sheets reacts with Al, Si and the like, present in the steel sheets, to form nitrides which are used as inhibitors.
  • Al-based nitrides including AlN, (Al 5 Si)N and (Al,Si,Mn)N, are used as inhibitors.
  • All of the above-described methods are methods of producing grain- oriented electrical steel sheets by reheating slabs at low temperature and forming additional precipitates in the steel sheets using a material or gas having nitriding ability.
  • the gas having nitriding ability is represented by ammonia, and the operation of nitriding using the gas after decarburization annealing, and associated problem, are as follows.
  • Nitriding via the decomposition of ammonia gas can be achieved at temperatures higher than 500 " C, which is the decomposition temperature of ammonia gas.
  • 500 " C is the decomposition temperature of ammonia gas.
  • temperatures around 500 ° C the diffusion rate of nitrogen in steel sheets is very low, and thus nitriding must be carried out for a long time.
  • temperatures higher than 800 ° C nitriding easily occurs, but primary recrystallized grains grow easily, so that the distribution of grains in steel sheets becomes non-uniform, making the development of secondary recrystallization unstable.
  • a suitable nitriding temperature range is considered to be 500-800 ° C .
  • the nitriding time should be excessively increased. Therefore, nitriding is carried out in the temperature range of 700-800 ° C due to problems associated with productivity.
  • a method of carrying out nitriding based on this fact is disclosed in Korean Patent Publication No. 95 -4710.
  • the amount of nitriding is determined by ammonia concentration, nitriding temperature and nitriding time, and the suitable amount of nitriding should be determined based on a combination of these conditions, hi view of productivity, nitriding should be achieved in a short time, and thus the ammonia concentration and nitriding temperature should be high.
  • the nitrogen concentration is increased mainly in the surface part of steel sheets thereof. Accordingly, the variation in nitrogen concentration through the thickness of steel sheets is greatly increased.
  • the central part of steel sheets is not substantially nitrified, and in the surface part, non-uniform nitriding is very evident. Also, the amount of nitriding is greatly influenced by the conditions of steel sheets, including surface roughness, grain size and chemical composition. When the surface roughness is high, the area of contact with atmospheric gas is increased, thus causing variation in the nitriding amount. When the grain size is small, the area of grain boundaries per unit area are increased, and the diffusion of nitrogen through the grain boundaries occurs faster than the diffusion of nitrogen through the grain interiors, thus causing variation in the nitriding amount.
  • the final annealing process is a very important process for obtaining the secondary recrystallized texture having the ⁇ 110 ⁇ 001> orientation.
  • the method disclosed in Korean Patent Publication No. 95-4710 in which nitriding is carried out after decarburization, comprises a process of transforming precipitates produced after nitriding annealing, in the final annealing process.
  • the precipitates, produced after nitriding annealing are Si 3 N 4 or (Si 5 Mn)N, which are easily decomposed due to their thermal instability.
  • such precipitates cannot be used as inhibitors, because they do not satisfy the conditions of the inhibitors.
  • these precipitates should be converted into thermally stable precipitates such as AlN or (Al 5 Si)N, such that they can function as inhibitors.
  • the precipitates should be maintained at a temperature of 700-800 ° C for at least 4 hours in the subsequent final annealing process, such that they can be transformed into precipitates that can be used as inhibitors. This means that the final annealing process becomes very lengthy and must be strictly controlled, which is very disadvantageous in terms of production cost.
  • the objects of the final annealing are to impart insulation properties through the formation of a glassy film by a reaction between an oxide layer formed in decarburization and MgO, and to form the ⁇ 110 ⁇ 001> texture by secondary recrystallization and to remove impurities which deteriorate magnetic properties.
  • a conventional final annealing method in a heating section before the initiation of secondary recrystallization, the steel sheets are maintained in a mixed gas of nitrogen and hydrogen to protect nitrides, which serve as grain growth inhibitors, such that secondary recrystallization can develop well. After the completion of secondary recrystallization, the steel sheets are maintained in an atmosphere of 100% hydrogen for a long time to remove impurities.
  • the final annealing heat cycle consists of a first soaking zone for removing water from an MgO coating, a heating zone for forming a glassy film and developing secondary recrystallization, a second soaking zone for removing N and S from AlN and MnS, which have served as inhibitors until completion of secondary recrystallization, and a cooling zone.
  • the temperature of the first soaking zone is set in the range from 650-850 ° C
  • the temperature of the second soaking zone is set in the range from 1150-1250 ° C
  • the zones having the greatest effect on the magnetic properties of grain-oriented electrical steel sheets are known to be the heating zone and the second soaking zone.
  • the heating rate in the heating zone is set to a very low rate of 10-17 0 C /hr. It is generally known that, as the heating rate is low, the ⁇ 110 ⁇ 001> sharpness of the secondary recrystallized grains is increased, thus providing excellent magnetic properties.
  • the above method has problems in that, in the final annealing process, the likelihood that the secondary recrystallization of grains having orientations other than the ⁇ 110 ⁇ 001> orientation will occur is increased, so that the ⁇ 110 ⁇ 001> sharpness of secondary recrystallized grains is reduced, thus deteriorating the magnetic properties.
  • the present invention has been made in order to solve the above- described problems occurring in the prior art, and it is an object of the present invention to provide a method of low-temperature-slab reheated, grain-oriented steel sheets having excellent magnetic properties with high productivity by managing the content of N and S, which are removed in the second soaking zone in the final annealing process, at a low level from a steel making process, controlling the amount of N, which is dissolved during slab reheating of hot rolling process, and at the same time, controlling the heating rate of the heating zone in secondary recrystallization annealing in two different steps.
  • Another object of the present invention is to provide a method of producing grain-oriented electrical steel sheets having excellent magnetic properties with high productivity by adding a suitable amount of the sulf ⁇ de- forming element Cu to inhibit grain growth in the primary recrystallization step and make the size of primary recrystallized grains uniform, thus stably forming secondary recrystallized grains.
  • Still another object of the present invention is to provide a method of producing grain-oriented electrical steel sheets having excellent magnetic properties with high productivity through a low-temperature slab reheating process by adding a suitable amount of the grain-boundary segregation element Sb to inhibit grain growth in the primary recrystallization step so as to eliminate the non-uniformity of the size of primary recrystallized grains through the thickness of the sheets, and at the same time, to stably form secondary recrystallized grains, thus improving the magnetic properties and increasing the productivity of the steel sheets.
  • the present invention provides a method for producing a grain-oriented electrical steel sheet having excellent magnetic properties with high productivity, the method comprising reheating a slab for the grain-oriented electrical steel sheet to a temperature at which precipitates in the slab are partially dissolved, hot-rolling, hot-band annealing, cold-rolling, subjecting the cold-rolled sheet to simultaneous decarburization and nitriding annealing in an atmosphere of a mixed gas of ammonia, hydrogen and nitrogen, and then subjecting the sheet to final annealing, wherein the slab is reheated such that the amount of N that is dissolved during the slab reheating is in a range of 0.0010-0.0040%.
  • the grain- oriented electrical steel sheet (hereinafter, referred to as a "first electrical steel sheet”) contains, in wt%, 2.0-4.0% Si, 0.020-0.040% acid soluble Al, less than 0.20% Mn, less than 0.0055% N, 0.04-0.07% C, less than 0.0055% S, and 0.02- 0.075% P or 0.05-0.35% Cr, and includes the balance of Fe and other unavoidable impurities.
  • the grain-oriented electrical steel sheet (hereinafter, referred to as a "second electrical steel sheet”) contains, in wt%, 2.0-4.0% Si, 0.020-0.040% acid soluble Al, less than 0.20% Mn, less than 0.0055% N, 0.04-0.07% C, less than 0.0055% S, 0.05-0.50% Cu, and 0.02-0.075% P or 0.05-0.35% Cr, and includes the balance of Fe and other unavoidable impurities.
  • the grain-oriented electrical steel sheet (hereinafter, referred to as a "third electrical steel sheet”) contains, in wt%, 2.0-4.0% Si, 0.020-0.040% acid soluble Al, less than 0.20% Mn, less than 0.0055% N, 0.04-0.07% C, less than 0.0055% S, 0.01-0.15% Sb, and 0.02-0.075% P or 0.05-0.35% Cr, and includes the balance of Fe and other unavoidable impurities.
  • the heating rate in the heating zone is set in two steps in view of the temperature of initiation of secondary recrystallization, in which the heating rate in a heating zone is 18-75 °C/hr from first soaking temperature to 900-1020 ° C, and 10- 15 °C/hr from a temperature above 1020 ° C to second soaking temperature. Also, the temperature at which precipitates in the slab are partially dissolved is 1050-1250 ° C, and the secondary recrystallization temperature is in the range of 1020-1150 "C.
  • the average size of precipitates after hot rolling or the hot-band annealing is in the range of 300-3000 A, and the size of the primary recrystallized grains after the simultaneous decarburization and nitriding annealing is in the range of 18-30 [M-
  • the heating rate in the heating zone is 18-75 "C/hr from a first soaking temperature to 900-1020 ° C, and then 10-15 ° C/hr from a temperature above that temperature to a second soaking temperature.
  • the average size of precipitates after the hot rolling or the hot-band annealing is in the range of 300-3000 A, and the size of the primary recrystallized grains after the simultaneous decarburization and nitriding annealing is in the range of 18-30 ⁇ m.
  • the heating rate in the heating zone is set in two steps in view of the initiation temperature of secondary recrystallization, in which the heating rate in the heating zone is 18-75 °C/hr from a first soaking temperature to 900-1020 °C, and 10- 15 ° C /hr from a temperature above that temperature to a second soaking temperature. Also, the temperature at which precipitates in the slab are partially dissolved is 1050-1250 ° C, and the secondary recrystallization temperature is in the range of 1020-1150 "C.
  • the average size of precipitates after the hot rolling or the hot-band annealing is in the range of 300-3000 A, and the size of the primary recrystallized grains after the simultaneous decarburization and nitriding annealing is in the range of 18-30 ⁇ m-
  • the inventive method for producing a grain-oriented electrical steel sheet having excellent magnetic properties can be produced with high productivity by controlling the contents of N and S at low levels and, at the same time, limiting the amount of N that is dissolved during slab reheating of hot rolling process, and setting the heating rate in the heating zone in the final annealing process at a high rate in a temperature range in which secondary recrystallization is not initiated, and at a conventional rate in a temperature range in which secondary recrystallization occurs.
  • a low-temperature-slab reheated, grain-oriented electrical steel sheet having a higher magnetic property and productivity can be produced by inhibiting grain growth in the primary recrystallization step through the addition of a suitable amount of sulfide- forming element Cu so as to make the size of primary recrystallized grains uniform, thus stably forming secondary recrystallized grains.
  • a low-temperature-slab reheated, grain-oriented electrical steel sheet having a higher magnetic property and productivity can be produced by inhibiting grain growth in the primary recystallization step through the addition of the grain-boundary segregation element Sb so as to eliminate the non-uniformity of the size of primary recrystallized grains through the thickness of the sheet, thus stably forming secondary recrystallized grains.
  • Nitriding is carried out after decarburization or at the same time as decarburization, and nitrogen produced by the decomposition of ammonia gas flows into steel sheets to form nitrides.
  • the method of carrying out nitriding after decarburization is carried out at 700-800 ° C
  • the method of carrying out decarburization and nitriding at the same time is carried out at 800-950 ° C in an atmosphere of ammonia + hydrogen + nitrogen.
  • these two methods are based on metallurgically different technical concepts, rather than a mere difference between nitriding methods or annealing temperatures therebetween.
  • the method of forming precipitates through a separate nitriding process after decarburization is carried out at an annealing temperature of less than 800 ° C, at which nitrides such as Si 3 N 4 and (Si 5 Mn)N are formed.
  • nitrides such as Si 3 N 4 and (Si 5 Mn)N are formed.
  • Such precipitates are easily formed at low temperature, but are thermally very unstable. Thus, such precipitates are readily decomposed at high temperatures, and thus cannot be used as inhibitors in grain-oriented electrical steel sheets.
  • nitrides are formed locally at the surface part of steel sheets.
  • these precipitates should be decomposed again in the final annealing process, which is a subsequent process, such that they should be re- precipitated with other elements present in steel sheets.
  • the precipitates produced at this time are stable nitrides such as AlN or (Al 5 Si)N, which can be inhibitors in grain-oriented electrical steel sheets.
  • the method of forming precipitates through simultaneous decarburization and nitriding requires an annealing temperature of more than 800 ° C. This temperature is set in consideration of the fact that a temperature of less than 800 ° C is not industrially useful, because the annealing time at that temperature is excessively long, and the fact that nitrides can be relatively stably produced by allowing the diffusion of nitrogen to actively occur.
  • the second soaking zone can also be shortened, thus greatly reducing the final annealing time.
  • the non-uniformity of the size of primary recrystallized grains is increased compared to that in the process of carrying out nitriding after decarburization, and the excessively grown grains can be secondarily recrystallized due to the size advantage, thus deteriorating the magnetic properties of final products.
  • this problem can be prevented by adding a suitable amount of Cu or Sb.
  • Cu is finely precipitated as sulfides in the hot rolling step to inhibit the excessive growth of primary recrystallized grains, and Sb segregates in grain boundaries to inhibit the excessive growth of primary recrystallized grains, so that the size of grains can be uniform through the thickness of sheets.
  • Sb segregates in grain boundaries to inhibit the excessive growth of primary recrystallized grains, so that the size of grains can be uniform through the thickness of sheets.
  • Si is the basic element of electrical steel sheets, and serves to increase the resistivity of materials and to reduce the core loss of the materials. If the content of Si is less than 2.0%, resistivity will decrease, and the core loss characteristics will consequently be deteriorated, and if it is more than 4.0%, the brittleness of steel will be increased, in which case cold rolling becomes very difficult, and the formation of secondary recrystallized grains becomes unstable. For this reason, the content of Si is limited to 2.0-4.0%.
  • Al forms nitrides such as AlN, (Al 5 Si)N or (Al 5 Si 5 Mn)N, which act as inhibitors. If the content of Al is less than 0.02%, it cannot provide the sufficient effect of inhibitors, and if it is excessively high, Al-based nitrides precipitate too coarsely, and thus the resulting inhibitors will show insufficient effects. For this reason, the content of Al is limited to 0.02-0.04%.
  • Mn has the effect of increasing resistivity to reduce core loss in the same manner as Si. Also, it reacts with nitrogen introduced by nitriding treatment together with Si to form a precipitate of (Al 5 Si 5 Mn)N to inhibit the growth of primary recrystallized grains, thus playing an important role in secondary recrystallization.
  • it when it is added in an amount of more than 0.20%, it will promote austenite phase transformation to reduce the size of primary recrystallized grains, thus making secondary recrystallization unstable. Accordingly, the content of Mn is limited to less than 0.20%.
  • N is contained in an amount of more than 0.0055% in a steel making step, the size of primary recrystallized grains will be reduced, leading to a decrease in the temperature of initiation of secondary recrystallization.
  • grains having orientations other than the ⁇ 110 ⁇ 001> orientation will also be subjected to secondary recrystallization, thus deteriorating the magnetic properties thereof, and a long time is required to remove N in the second soaking zone of the final annealing process, making it difficult to produce a grain-oriented steel sheet at high productivity.
  • the content of N in steel is as low as 0.0055% or lower, the effect of coarsening the size of initial grains before cold rolling will be obtained, and thus the number of grains having the ⁇ 110 ⁇ 001> orientation in the primary recrystallized sheet will be increased, so that the size of secondary recrystallized grains will be reduced, thus improving the magnetic properties of final products. Accordingly, the content of N is limited to less than 0.0055%.
  • C When C is added in an amount of more than 0.04%, it will promote the austenite phase transformation of steel, so that a hot-rolled texture will made fine during a hot rolling process, thus assisting in the formation of a uniform fine texture.
  • the content thereof is more than 0.07%, coarse carbides will be precipitated, and it will be difficult to remove carbon during decarburization. Accordingly, the content of C is limited to 0.04-0.07%.
  • P promotes the growth of primary recrystallized grains in low- temperature-slab reheated, grain-oriented electrical steel sheets, so that it increases the temperature of secondary recrystallization, thus improving the sharpness of ⁇ 110 ⁇ 001> grains in final products. Meanwhile, P not only reduces the core loss of final products by increasing the number of ⁇ 110 ⁇ 001> grains in primary recrystallized sheets, but also improves the sharpness of ⁇ 110 ⁇ 001> grains in final products by strongly developing the ⁇ 111 ⁇ 112> texture in the primary recrystallized sheets, thus increasing the magnetic flux density of the products.
  • P has the function of segregating in grain boundaries up to a high temperature of about 1000 ° C during secondary recrystallization annealing to thus retard the decomposition of precipitates so as to enhance the inhibiting force by the precipitates.
  • P needs to be added in an amount of more than 0.02%.
  • P is added in an amount of more than 0.075%, the size of primary recrystallized grains will be reduced instead of being increased, so that secondary recrystallization will be unstable, and in addition, the brittleness of steel will be increased, thus making the cold rolling of steel difficult. Accordingly, the content of P is limited to 0.02%- 0.075%.
  • Cr this function of P will be offset, and thus if P is added, the preferred content of Cr will be less than 0.05%.
  • Cr is a ferrite forming element, acts to grow primary recrystallized grains, and increases ⁇ 110 ⁇ 001> grains in primary recrystallized sheets.
  • Cr needs to be added in an amount of more than 0.05%.
  • the content of Cr is limited to 0.05-0.35%.
  • the content of P adversely affects the useful function of Cr.
  • P segregates in grain boundaries from the hot rolling step, so that it adversely affects the growth of primary recrystallized grains by Cr, and in addition, increases the brittleness of steel, thus deteriorating the cold rolling of the steel difficult. Accordingly, when Cr is added, the content of P is limited to less than 0.02%.
  • Cu can finely precipitate in the hot rolling step to thus act as an inhibitor against the growth of primary recrystallized grains, and does not substantially act as an inhibitor against the growth of secondary recrystallized grains.
  • Cu In order for Cu to inhibit the excessive growth of primary recrystallized grains, Cu needs to be added in an amount of more than 0.05%. Meanwhile, if Cu is contained in an amount of more than 0.50%, the size of primary recrystallized grains will be excessively reduced, so that the temperature of initiation of secondary recrystallization will be lowered, thus deteriorating magnetic properties. Accordingly, the content of Cu is limited to 0.05-0.50%.
  • Sb segregates in grain boundaries to inhibit the excessive growth of primary recrystallized grains.
  • Sb is added in an amount of less than 0.01%, the function thereof will be difficult to sufficiently exhibit.
  • it is contained in an amount of more than 0.15%, the size of primary recrystallized grains will be excessively reduced, so that the temperature of initiation of secondary recrystallization will be lowered, thus deteriorating magnetic properties.
  • the ability to inhibit the growth of grains will also be excessively increased, so that secondary recrystallized grains cannot be formed. Accordingly, the content of Sb is limited to the range of 0.01 - 0.15%.
  • the reheating temperature of a slab before hot rolling is the temperature at which precipitates in the slab are partially dissolved, but the reheating temperature is determined such that the amount of N to be dissolved is in the range of 0.0010- 0.0040%. Generally, the temperature at which precipitates in the slab are partially dissolved is below 1250 °C .
  • the present inventors have found that a factor having a decisive effect on the size of primary recrystallized grains is not the amount of N in a steel making step, but rather the amount of N dissolved during slab reheating in a hot rolling process.
  • the slab-reheating temperature should be 1050 "C in order for the amount of N dissolved to be 0.0010%.
  • the heating temperature should be 1250 ° C in order for the amount of N dissolved to be 0.0040%.
  • the heating temperature is below 1050 ° C, the hot rolling of slabs will be difficult to carry out, and if the heating temperature is above 1250 ° C , fine precipitates will be formed in the hot rolling step, and the size of primary recrystallized grains will consequently be reduced, making it difficult to expect stable secondary recrystallization.
  • the amount of N dissolved during slab reheating is less than 0.0010%, the average size of primary recrystallized grains will be excessively increased, in which case that secondary recrystallization will not occur, thus greatly deteriorating magnetic properties. Even when the average size of grains is reduced by lowering the primary recrystallization annealing temperature, it is impossible to avoid the problem in which the surface properties are deteriorated. Meanwhile, when the amount of N dissolved is more than 0.0040%, the average size of primary recrystallized grains will be reduced, so that the secondary recrystallization temperature will be lowered, thus deteriorating the sharpness of ⁇ 110 ⁇ 001> texture. Accordingly, the amount of N dissolved during slab reheating is limited to the range of 0.0010- 0.0040%.
  • the electrical steel sheet slab, reheated as described above, is hot-rolled according to a conventional method.
  • the final thickness of a hot-rolled steel sheet is generally 2.0-3.5 mm.
  • the hot-rolled sheet is subjected to hot-band annealing, and then to cold cooling to a final thickness of 0.23-0.35 mm.
  • hot-band annealing can be performed using various methods, a method comprising heating the sheet to 1000-1200 ° C and soaking the heated sheet at 850-950 0 C, followed by cooling, is used in the present invention.
  • the average size of precipitates after hot rolling or hot-band annealing is 300-3000 A .
  • the cold-rolled sheet is subjected to concurrent decarburization and nitriding annealing in an atmosphere of a mixed gas of ammonia + hydrogen + nitrogen.
  • nitriding can be carried out in any process after cold rolling, because it is a process in which nitrogen is introduced into steel to form nitrides for use as inhibitors. That is, during decarburization or a separate nitriding annealing process following decarburization, nitrogen can be introduced into steel using ammonia gas.
  • the method of carrying out decarburization and nitriding simultaneously is an economical and simple process.
  • the dew point of a mixed gas of hydrogen and nitrogen varies depending on the annealing temperature and the composition of the mixed gas, and is set such that decarburization ability is maximized.
  • the simultaneous decarburization and nitriding annealing is preferably carried out at a temperature of 800-950 ° C. If the annealing temperature is below 800 ° C, a long time will be required for decarburization, and the size of primary recrystallized grains will also be reduced, so that stable secondary recrystallization in final annealing cannot be expected.
  • the time of concurrent decarburization and nitriding annealing is determined by the annealing temperature and the concentration of the added ammonia gas, and the annealing time is generally more than 30 seconds. At this time, the size of primary recrystallized grains is controlled in the range of 18-30 (M.
  • grain-oriented electrical steel sheets having excellent magnetic properties are produced by applying a MgO-based annealing separator on steel sheets, and then subjecting the steel sheets to final annealing for a long time to induce secondary recrystallization, thus forming a ⁇ 110 ⁇ 001> texture in which the ⁇ 110 ⁇ plane of the secondary recrystallized grains is parallel to the rolling plane and the ⁇ 001> direction is parallel to the rolling direction.
  • the objects of the final annealing are to impart insulation properties through the formation of a glassy film by a reaction between an oxide layer formed in decarburization and MgO, to form the ⁇ 110 ⁇ 001> texture by secondary recrystallization, and to remove impurities, which deteriorates magnetic properties.
  • a conventional final annealing method in a heating zone before secondary recrystallization occurs, the steel sheets are maintained in a mixed gas of nitrogen and hydrogen to protect nitrides, serving as grain growth inhibitors, such that secondary recrystallization can develop well. After the completion of secondary recrystallization, the steel sheets are maintained in an atmosphere of 100% hydrogen for a long time to remove impurities.
  • the time required for final annealing is generally 135-160 hours, and varies slightly depending on the capacity and type of heat treatment furnace into which the steel sheet coil is charged.
  • the final annealing process requiring a long time as described above, has received the most attention in the process for producing grain-oriented electrical steel sheets, and efforts to shorten the final annealing time have been continuously attempted, but a satisfactory result has not yet been obtained.
  • zones having the greatest effect on the magnetic properties of grain-oriented electrical steel sheets are a heating zone and a second soaking zone.
  • the heating rate in the heating zone is generally set to a very slow rate of 10-15 "C /hours.
  • the present inventors have paid attention to the fact that, when an Al-based inhibitor is used in a process of low-temperature slab reheating, the size of primary recrystallized grains in the final annealing process is not substantially changed immediately before secondary recrystallization is initiated, and thus the primary recrystallized texture is not changed either. As a result, the present inventors found that the heating rate in the temperature range in which secondary recrystallization does not occur has little or no effect on secondary recrystallization behavior. From this fact, the present inventors have found that, when the heating rate in the heating zone is set in two steps based on the temperature range in which secondary recrystallization occurs, the heating zone of the final annealing process can be greatly shortened.
  • the present invention it is possible to shorten the time significantly without deteriorating magnetic properties, by elevating the temperature in the heating zone at a rate of 18-75 ° C/hr from the first soaking temperature to the temperature of initiation of secondary recrystallization and elevating the temperature from the temperature of initiation of secondary recrystallization to the second soaking temperature.
  • the temperature on which the two-step heating is based is in the range of 900-1020 °C .
  • the upper limit of the temperature is 1020 ° C.
  • the variation between the highest temperature and the lowest temperature in the steel sheet coil will be excessively increased, so that the surface characteristics of the steel sheet will be greatly deteriorated, and in addition, the secondary recrystallization of the steel sheet will be unstable, thus deteriorating the magnetic properties of the steel sheet.
  • the reason why the lower limit of the temperature is 900 ° C is because, at temperatures lower than 900 0 C, the effect of the two-step heating will not be apparent. Accordingly, considering the correlation between the temperature variation in the steel sheet coil and the surface characteristic and magnetic properties of the steel sheet, the temperature is limited to the range to 900-1020 ° C.
  • the reason why the heating rate is limited to below 75 0 C /hr is that, when the heating rate is higher than 75 ° C/hr, the temperature variation in the sheet coil will be increased, thus adversely affecting the surface characteristics of the sheet.
  • the reason why the heating rate is limited to above 18 ° C/hr is that, when the heating rate is lower than 18 ° C/hr, the heating time will be increased, leading to a reduction in productivity.
  • Examples 1-4 relate to a first electrical steel sheet; Examples 5-6 to a second electrical steel sheet; and Examples 7-8 to a third electrical steel sheet.
  • the steel sheets were applied with an annealing separator MgO and finally annealed in a coil state.
  • the first soaking temperature in the final annealing was 700 "C
  • the heating rate in a heating zone between 700 and 1200 ° C were varied in the conditions shown in Table 1 below
  • the atmosphere of the final annealing was a mixed gas of 25% nitrogen + 75% hydrogen up to 1200 " C .
  • comparative materials 2 and 3 in which the heating rate in the entire heating zone was increased, showed poor magnetic properties compared to those of comparative material 1.
  • the cold- rolled sheets were subjected to simultaneous decarburization and nitriding by introducing a mixed gas of 75% hydrogen and 25% nitrogen, having a dew point of 65 °C, and 1% dry ammonia gas, into a furnace at 875 °C, and maintaining the cold-rolled sheets in the atmosphere gas for 180 seconds.
  • the steel sheets were applied with an annealing separator MgO and finally annealed in a coil state.
  • the first soaking temperature in the final annealing was 700 0 C
  • the second soaking temperature was 1200 ° C
  • the heating rate in the heating zone were 45 ° C/hr in the temperature range of 700- 950 0 C, and 15 ° C/hr in the temperature range of 950-1200 "C .
  • the soaking time at 1200 ° C was varied as shown in Table 2.
  • the atmosphere of the final annealing was a mixed gas of 25% nitrogen + 75% hydrogen up to 1200 "C , and 100% hydrogen at 1200 ° C and higher.
  • the steel sheets were cooled in the furnace.
  • the magnetic properties, measured for various process conditions, are shown in Table 2. [Table 2]
  • the inventive materials had S and N contents at conventional levels, even when the secondary soaking time was greatly reduced. Also, the inventive materials showed excellent magnetic properties compared to the comparative materials, in which the second soaking time was 25 hours. Thus, it can be seen that, according to the present invention, it is possible to improve both the magnetic properties and productivity of grain-oriented electrical steel sheets simultaneously.
  • the cold-rolled sheets were subjected to simultaneous decarburization and nitriding by introducing a mixed gas of 75% hydrogen and 25% nitrogen, having a dew point of 65 ° C, and 1% dry ammonia gas, into a furnace at 875 ° C, and maintaining the cold-rolled sheets in the atmosphere gas for 180 seconds.
  • the steel sheets were applied with an annealing separator MgO and finally annealed in a coil state.
  • the first soaking temperature in the final annealing was 700 ° C
  • the second soaking temperature was 1200 ° C
  • the heating rate in the heating zone were 45 °C/hr in the temperature range of 700- 950 ° C and 15 ° C/hr in the temperature range of 950-1200 °C .
  • the atmosphere of the final annealing was a mixed gas of 25% nitrogen + 75% hydrogen up to 1200 ° C , and 100% hydrogen at 1200 ° C and higher for 20 hours. Then, the steel sheets were cooled in the furnace.
  • Table 3 The magnetic properties measured for various process conditions are shown in Table 3. [Table 3]
  • the cold- rolled sheets were subjected to simultaneous decarburization and nitriding by introducing a mixed gas of 75% hydrogen and 25% nitrogen, having a dew point of 65 " C, and 1% dry ammonia gas, into a furnace at 875 "C, and maintaining the cold-rolled sheets in the atmosphere gas for 180 seconds.
  • the steel sheets were applied with an annealing separator MgO and finally annealed in a coil state.
  • the first soaking temperature in the final annealing was 700 "C
  • the second soaking temperature was 1200 “C
  • the heating rate in the heating zone were 45 ° C/hr in the temperature range of 700-
  • the atmosphere of the final annealing was a mixed gas of 25% nitrogen + 75% hydrogen up to 1200 ° C, and 100% hydrogen at 1200 ° C and higher. Then, the steel sheets were cooled in the furnace.
  • the magnetic properties, measured for various process conditions, are shown in Table 4.
  • the inventive materials showed excellent magnetic properties compared to those of the comparative materials in which the contents of S and N were at conventional levels and the second soaking time was 25 hours.
  • the present invention it was possible to improve the magnetic properties and productivity of grain-oriented electrical steel sheets simultaneously.
  • the hot-rolled steel sheets were heated to 1095 ° C, maintained at 900 ° C for 90 seconds, quenched in water, washed with acid, and then cold-rolled to a thickness of 0.30 mm.
  • the cold-rolled sheets were subjected to simultaneous decarburization and nitriding by introducing a mixed gas of 75% hydrogen and 25% nitrogen, having a dew point of 64 ° C, and 1% dry ammonia gas into a furnace at 875 ° C , and maintaining the cold-rolled sheets in the atmosphere gas for 180 seconds.
  • the steel sheets were applied with the annealing separator MgO and finally annealed in a coil state.
  • the first soaking temperature in the final annealing was 700 ° C
  • the second soaking temperature was 1200 °C
  • the heating rate in the heating zone were 45 ° C/hr in the temperature range of 700- 950 ° C, and 15 ° C/hr in the temperature range of 950-1200 ° C. Meanwhile, the soaking time at 1200 ° C was 15 hours.
  • the atmosphere of the final annealing was a mixed gas of 25% nitrogen + 75% hydrogen up to 1200 ° C, and 100% hydrogen at 1200 ° C and higher. Then, the steel sheets were cooled in the furnace.
  • the magnetic properties measured for various process conditions are shown in Table 5. [Table 5]
  • the inventive materials 9-12 in which Cu was added in an amount within the range of the present invention, showed excellent magnetic properties compared to those of comparative materials 24-25.
  • the cold-rolled sheets were subjected to simultaneous decarburization and nitriding by introducing a mixed gas of 75% hydrogen and 25% nitrogen, having a dew point of 66 "C, and 1% dry ammonia gas into a furnace at 875 ° C, and maintaining the cold-rolled sheets in the atmosphere gas for 180 seconds.
  • the steel sheets were applied with the annealing separator MgO and finally annealed in a coil state.
  • the first soaking temperature in the final annealing was 700 0 C
  • the second soaking temperature was 1200 ° C
  • the heating rate in the heating zone were 45 ° C/hr in the temperature range of 700- 950 ° C, and 15 ° C/hr in the temperature range of 950-1200 ° C .
  • the atmosphere of the final annealing was a mixed gas of 25% nitrogen + 75% hydrogen up to 1200 °C, and 100% hydrogen at 1200 °C and higher.
  • the steel sheets were cooled in the furnace.
  • the magnetic properties, measured for various process conditions, are shown in Table 6. [Table 6]
  • the inventive materials 13-15 in which the amount of N dissolved during slab reheating satisfied the range of the present invention, showed excellent magnetic properties compared to those of comparative materials 26-27.
  • the hot-rolled steel sheets were heated to 1120 ° C, maintained at 920 ° C for 90 seconds, quenched in water, washed with acid, and then cold-rolled to a thickness of 0.30 mm.
  • the cold-rolled sheets were subjected to simultaneous decarburization and nitriding by introducing a mixed gas of 75% hydrogen and 25% nitrogen, having a dew point of 65 0 C , and 1% dry ammonia gas, into a furnace at 875 ° C, and maintaining the cold-rolled sheets in the atmosphere gas for 180 seconds.
  • the steel sheets were applied with the annealing separator MgO and finally annealed in a coil state.
  • the first soaking temperature in the final annealing was 700 ° C
  • the second soaking temperature was 1200 "C
  • the heating rate in the heating zone were 45 ° C/hr in the temperature range of 700- 950 ° C, and 15 ° C/hr in the temperature range of 950-1200 ° C .
  • the soaking time at 1200 ° C was 15 hours.
  • the atmosphere of the final annealing was a mixed gas of 25% nitrogen + 75% hydrogen up to 1200 °C, and 100% hydrogen at 1200 ° C or higher.
  • the steel sheets were cooled in the furnace.
  • the magnetic properties, measured for various process conditions, are shown in Table 7. [Table 7]
  • inventive materials 16-19 in which Sb was added in amounts within the range of the present invention, had excellent magnetic properties compared to those of comparative materials 28-29.
  • the cold-rolled sheets were subjected to simultaneous decarburization and nitriding by introducing a mixed gas of 75% hydrogen and 25% nitrogen, having a dew point of 65 " C , and 1% dry ammonia gas, into a furnace at 875 ° C, and maintaining the cold-rolled sheets in the atmosphere gas for 180 seconds.
  • the steel sheets were applied with annealing separator MgO and finally annealed in a coil state.
  • the first soaking temperature in the final annealing was 700 °C
  • the second soaking temperature was 1200 0 C
  • the heating rate in the heating zone were 45 0 C /hr in the temperature range of 700-950 ° C and 15 °C/hr in the temperature range of 950-1200 ° C.
  • the atmosphere of the final annealing was a mixed gas of 25% nitrogen + 75% hydrogen up to 1200 °C, and 100% hydrogen at 1200 0 C or higher for 15 hours.
  • the steel sheets were cooled in the furnace.
  • Table 8 The magnetic properties measured for various process conditions are shown in Table 8 below. [Table 8]
  • the inventive materials 20-22 in which the amount of N dissolved during slab reheating fell within the range of the present invention, showed excellent magnetic properties compared to those of comparative materials 30-31.

Landscapes

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

Abstract

La présente invention concerne un procédé de production d'une tôle en acier magnétique à grains orientés ayant d'excellentes propriétés magnétiques avec une grande productivité. Selon le procédé décrit, une tôle en acier magnétique à grains orientés, d'une brame réchauffée à basse température, peut être produite en limitant les teneurs en N et S à de faibles niveaux dans une étape de fabrication d'acier, en limitant la quantité de N qui est dissoute durant le réchauffage de la brame dans un procédé de laminage à chaud, et en contrôlant un taux de chauffage dans la zone de chauffage du procédé de recuit final à un degré élevé dans une plage de températures dans laquelle la recristallisation secondaire n'est pas initiée, et à un niveau conventionnel dans une plage de températures dans laquelle la recristallisation secondaire se produit.
PCT/KR2007/006723 2006-12-27 2007-12-21 Procédé de fabrication de tôles en acier magnétiques à grains orientés ayant une excellente propriété magnétique et une grande productivité WO2008078915A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN2007800484506A CN101573458B (zh) 2006-12-27 2007-12-21 高产率地生产具有优异磁特性的晶粒定向电工钢板的方法

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
KR10-2006-0134910 2006-12-27
KR1020060134910A KR100797997B1 (ko) 2006-12-27 2006-12-27 자성과 생산성이 우수한 방향성 전기강판의 제조방법
KR10-2007-0078963 2007-08-07
KR1020070078963A KR101394452B1 (ko) 2007-08-07 2007-08-07 자성과 생산성이 우수한 방향성 전기강판의 제조방법
KR10-2007-0084448 2007-08-22
KR1020070084448A KR101408230B1 (ko) 2007-08-22 2007-08-22 자성과 생산성이 우수한 방향성 전기강판의 제조방법

Publications (1)

Publication Number Publication Date
WO2008078915A1 true WO2008078915A1 (fr) 2008-07-03

Family

ID=39562671

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2007/006723 WO2008078915A1 (fr) 2006-12-27 2007-12-21 Procédé de fabrication de tôles en acier magnétiques à grains orientés ayant une excellente propriété magnétique et une grande productivité

Country Status (1)

Country Link
WO (1) WO2008078915A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120312424A1 (en) * 2010-02-18 2012-12-13 Kenichi Murakami Method of manufacturing grain-oriented electrical steel sheet
EP3128028A1 (fr) * 2014-03-31 2017-02-08 JFE Steel Corporation Tôle recuite de recristallisation primaire pour tôle d'acier électromagnétique orientée et procédé de production de tôle d'acier électromagnétique orientée
EP3235914A4 (fr) * 2014-12-18 2017-11-08 Posco Tôle d'acier électrique à grains orientés et procédé pour la fabriquer

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59190324A (ja) * 1983-04-09 1984-10-29 Kawasaki Steel Corp 磁束密度の高い一方向性けい素鋼板の製造方法
JPS59190325A (ja) * 1983-04-09 1984-10-29 Nippon Steel Corp 連続鋳造法を適用した鉄損の優れた一方向性珪素鋼板の製造法
JPH06256847A (ja) * 1993-03-03 1994-09-13 Nippon Steel Corp 磁気特性の優れた一方向性電磁鋼板の製造方法
JPH07138643A (ja) * 1993-11-16 1995-05-30 Nippon Steel Corp 磁気特性の優れた一方向性電磁鋼板の製造方法
KR20060074648A (ko) * 2004-12-28 2006-07-03 주식회사 포스코 자기특성이 우수한 방향성 전기강판 및 그 제조방법

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59190324A (ja) * 1983-04-09 1984-10-29 Kawasaki Steel Corp 磁束密度の高い一方向性けい素鋼板の製造方法
JPS59190325A (ja) * 1983-04-09 1984-10-29 Nippon Steel Corp 連続鋳造法を適用した鉄損の優れた一方向性珪素鋼板の製造法
JPH06256847A (ja) * 1993-03-03 1994-09-13 Nippon Steel Corp 磁気特性の優れた一方向性電磁鋼板の製造方法
JPH07138643A (ja) * 1993-11-16 1995-05-30 Nippon Steel Corp 磁気特性の優れた一方向性電磁鋼板の製造方法
KR20060074648A (ko) * 2004-12-28 2006-07-03 주식회사 포스코 자기특성이 우수한 방향성 전기강판 및 그 제조방법

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120312424A1 (en) * 2010-02-18 2012-12-13 Kenichi Murakami Method of manufacturing grain-oriented electrical steel sheet
US9175362B2 (en) * 2010-02-18 2015-11-03 Nippon Steel & Sumitomo Metal Corporation Method of manufacturing grain-oriented electrical steel sheet
EP3128028A1 (fr) * 2014-03-31 2017-02-08 JFE Steel Corporation Tôle recuite de recristallisation primaire pour tôle d'acier électromagnétique orientée et procédé de production de tôle d'acier électromagnétique orientée
EP3128028A4 (fr) * 2014-03-31 2017-05-03 JFE Steel Corporation Tôle recuite de recristallisation primaire pour tôle d'acier électromagnétique orientée et procédé de production de tôle d'acier électromagnétique orientée
EP3235914A4 (fr) * 2014-12-18 2017-11-08 Posco Tôle d'acier électrique à grains orientés et procédé pour la fabriquer
US10851431B2 (en) 2014-12-18 2020-12-01 Posco Grain-oriented electrical steel sheet and manufacturing method therefor

Similar Documents

Publication Publication Date Title
KR100721822B1 (ko) 저철손 고자속밀도를 갖는 방향성 전기강판 제조방법
WO2017111509A1 (fr) Tôle d'acier magnétique à grains orientés et procédé de fabrication s'y rapportant
KR100797997B1 (ko) 자성과 생산성이 우수한 방향성 전기강판의 제조방법
WO2008078915A1 (fr) Procédé de fabrication de tôles en acier magnétiques à grains orientés ayant une excellente propriété magnétique et une grande productivité
KR101506677B1 (ko) 방향성 전기강판 및 그 제조방법
KR101539751B1 (ko) 방향성 전기강판 및 그 제조방법
CN113195770B (zh) 取向电工钢板及其制造方法
KR100359239B1 (ko) 자기특성과 경제성이 우수한 고자속 밀도 방향성 전기강판의 제조방법
KR101141279B1 (ko) 자기특성이 우수한 방향성 전기강판 제조방법
WO2008078947A1 (fr) Procédé de fabrication de tôles d'acier magnétiques à grains orientés
KR102538120B1 (ko) 방향성 전기강판 및 그의 제조방법
KR20020044243A (ko) 자기특성이 우수한 방향성 전기강판의 제조방법
KR20140084898A (ko) 방향성 전기강판 및 그 제조방법
KR101539752B1 (ko) 방향성 전기강판 및 그 제조방법
KR100721819B1 (ko) 철손이 낮고 자속밀도가 높은 방향성 전기강판 제조방법
KR102597512B1 (ko) 방향성 전기강판 및 그의 제조방법
KR101131721B1 (ko) 자기 특성이 우수한 방향성 전기강판의 제조방법
KR102405173B1 (ko) 방향성 전기강판 및 그의 제조방법
KR100359242B1 (ko) 고자속 밀도 방향성 전기강판의 저온가열식 제조방법
KR100345696B1 (ko) 슬라브저온가열에의한고자속밀도일방향성전기강판의제조방법
KR20020044244A (ko) 방향성 전기강판의 제조방법
KR100530056B1 (ko) 생산성이 우수한 방향성 전기강판의 제조방법
KR100479995B1 (ko) 자속밀도가 우수한 방향성 전기강판의 제조방법
KR100256336B1 (ko) 자기적특성이 우수한 방향성 규소강의 제조방법
KR20230095517A (ko) 방향성 전기강판 및 이의 제조 방법

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 200780048450.6

Country of ref document: CN

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07851689

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 07851689

Country of ref document: EP

Kind code of ref document: A1