Classifications

• • 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
• • 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
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
  • C21D1/76—Adjusting the composition of the atmosphere
• • 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
  • C21D6/00—Heat treatment of ferrous alloys
  • C21D6/005—Heat treatment of ferrous alloys containing Mn
• • 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
  • C21D6/00—Heat treatment of ferrous alloys
  • C21D6/008—Heat treatment of ferrous alloys containing Si
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1216—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the working steps
  • C21D8/1222—Hot rolling
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1216—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the working steps
  • C21D8/1233—Cold rolling
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment
  • C21D8/1261—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment following hot rolling
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment
  • C21D8/1266—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment between cold rolling steps
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties characterised by the heat treatment
  • C21D8/1272—Final recrystallisation annealing
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1277—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular surface treatment
  • C21D8/1283—Application of a separating or insulating coating
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
• • 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
  • C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
• • 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
  • C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
• • 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
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
• • 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
  • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
• • 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
  • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
• • 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
  • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
• • 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
  • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
  • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
  • C23G1/08—Iron or steel
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
  • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
  • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
  • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
  • H01F1/147—Alloys characterised by their composition
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
  • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
  • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
  • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
  • H01F1/147—Alloys characterised by their composition
  • H01F1/14766—Fe-Si based alloys
  • H01F1/14775—Fe-Si based alloys in the form of sheets
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
  • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
  • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
  • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
  • H01F1/147—Alloys characterised by their composition
  • H01F1/14766—Fe-Si based alloys
  • H01F1/14791—Fe-Si-Al based alloys, e.g. Sendust
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
  • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
  • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
  • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
  • H01F1/16—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/20—Recycling

Definitions

• the present invention relates to non-oriented electrical steel sheets and a manufacturing method thereof.
• the motor cores of the various motors mentioned above are composed of a stator, which is the fixed part, and a rotor, which is the rotating part.
• the characteristics required for the stator and rotor that make up the motor core are not the same.
• the stator is required to have excellent magnetic properties (low iron loss and high magnetic flux density), while the rotor is required to have low iron loss and excellent mechanical properties (high strength).
• non-oriented electromagnetic steel sheets Because the characteristics required for the stator and rotor are different, the desired characteristics can be achieved by producing separate non-oriented electromagnetic steel sheets for the stator and rotor. However, preparing two types of non-oriented electromagnetic steel sheets complicates the manufacturing process of the iron core and leads to a decrease in yield. Therefore, in order to achieve the low iron loss and high strength required for the rotor while also achieving the low iron loss and high magnetic flux density required for the stator, non-oriented electromagnetic steel sheets with excellent magnetic properties and strength have been considered.
• Patent Documents 1 to 4 attempt to achieve excellent magnetic properties and high strength.
• Patent Documents 1 to 4 it is necessary to include a large amount of alloying elements, which causes the problem of reduced toughness and increased susceptibility to breakage during cold rolling.
• the present invention was made to solve these problems, and aims to provide a stable supply of non-oriented electrical steel sheets with excellent magnetic properties and high strength.
• the present invention relates to the following non-oriented electrical steel sheet and its manufacturing method.
• the chemical composition of the base material is, in mass%, C: 0.0040% or less, Si: more than 3.50% and less than 4.50%, Mn: less than 0.60% Al: 0.30-0.90%, P: 0.030% or less, S: 0.0018% or less, N: 0.0040% or less, Ti: less than 0.0040% Nb: less than 0.0050%; Zr: less than 0.0050%; V: less than 0.0050%, Cu: less than 0.200% Ni: less than 0.500% Sn and Sb: 0.005 to 0.060% in total, The balance is Fe and impurities.
• the average crystal grain size of the base material is more than 40 ⁇ m and not more than 140 ⁇ m,
• the degree of accumulation of the ⁇ 111 ⁇ orientation at a position of 1/4 of the plate thickness from the surface of the base material is 4.0 or less,
• the plate thickness of the base material is 0.10 to 0.30 mm;
• Non-oriented electrical steel sheet 4.2 ⁇ Si+Al+0.5 ⁇ Mn ⁇ 4.9...(i)
• the element symbols indicate the content (mass %) of each element.
• the tensile strength is 580 MPa or more.
• the base material has an insulating coating on its surface.
• a method for producing a non-oriented electrical steel sheet according to any one of (1) to (3) above In mass percent, C: 0.0040% or less, Si: more than 3.50% and less than 4.50%, Mn: less than 0.60% Al: 0.30-0.90%, P: 0.030% or less, S: 0.0018% or less, N: 0.0040% or less, Ti: less than 0.0040% Nb: less than 0.0050%; Zr: less than 0.0050%; V: less than 0.0050%, Cu: less than 0.200% Ni: less than 0.500% Sn and Sb: 0.005 to 0.060% in total, The balance is Fe and impurities.
• Manufacturing method of non-oriented electrical steel sheet 4.2 ⁇ Si+Al+0.5 ⁇ Mn ⁇ 4.9...(i)
• the element symbols indicate the content (mass %) of each element.
• the inventors conducted extensive research to solve the above problems, and came to the following findings.
• the content of Si which has the highest solid solution strengthening ability and also contributes most to increasing electrical resistance, is set to more than 3.50% and not more than 4.50%.
• Al is set to 0.30% or more.
• the Al content is set to 0.90% or less to suppress deterioration of toughness.
• Mn has the lowest solid solution strengthening ability of the three elements, but it is an element that contributes to an increase in electrical resistance with little deterioration in toughness.
• Mn which has a lower solid solution strengthening ability than Si and Al, is contained in excess, the decrease in magnetic flux density is significant compared to the increase in strength, and if the Mn content is high, it becomes difficult to stably improve the magnetic properties. Therefore, the Mn content is set to less than 0.60%.
• the inventors therefore investigated a method for improving magnetic flux density while lowering the soaking temperature during annealing of the hot-rolled sheet. As a result, they discovered that rapid heating during finish annealing after cold rolling makes it possible to suppress the development of texture that is detrimental to magnetic properties, and that even when the soaking temperature during annealing of the hot-rolled sheet is low, it is possible to suppress the decrease in magnetic flux density.
• the inventors conducted experiments in which rapid heating was performed to various target temperatures, and found that rapid heating did not have any effect on improving the magnetic properties when the target temperature was low, but that rapid heating to a temperature of 850°C or higher improved the magnetic properties.
• the non-oriented electrical steel sheet according to one embodiment of the present invention has excellent magnetic properties and high strength, and is therefore suitable for both stators and rotors.
• the non-oriented electrical steel sheet according to this embodiment preferably has an insulating coating on the surface of the base material, which will be described below.
• C is an element that causes iron loss deterioration of non-oriented electrical steel sheets. If the C content exceeds 0.0040%, the iron loss of the non-oriented electrical steel sheet deteriorates and good magnetic properties cannot be obtained. Therefore, the C content is set to 0.0040% or less.
• the C content is preferably 0.0035% or less, and more preferably 0.0030% or less. Since C contributes to increasing the strength of the non-oriented electrical steel sheet, if it is desired to obtain this effect, the C content is preferably 0.0005% or more, and more preferably 0.0010% or more.
• Si more than 3.50% and not more than 4.50%
• Si is an element that increases the electrical resistance of steel, reduces eddy current loss, and improves the iron loss of non-oriented electrical steel sheets.
• Si is an element that is effective in increasing the strength of non-oriented electrical steel sheets because of its high solid solution strengthening ability.
• the Si content is made to be more than 3.50%.
• the Si content is preferably 3.60% or more, more preferably 3.70% or more, and even more preferably 3.80% or more.
• the Si content is made to be 4.50% or less.
• the Si content is preferably 4.40% or less, and more preferably 4.30% or less.
• Mn less than 0.60%
• Mn manganese
• Si and Al have poorer solid solution strengthening ability than Si and Al, a large amount of Mn is required to obtain high strength, and the magnetic flux density decreases significantly. Therefore, the Mn content is less than 0.60%.
• the Mn content is preferably 0.55% or less, and more preferably 0.50% or less. There is no need to set a lower limit for the Mn content, but if the above effect is to be obtained, the Mn content is preferably 0.10% or more, and more preferably 0.20% or more.
• Al 0.30-0.90%
• Al (aluminum) is an element that has the effect of increasing the electrical resistance of steel, thereby reducing eddy current loss and improving the iron loss of non-oriented electrical steel sheets.
• Al is an element that contributes to increasing the strength of non-oriented electrical steel sheets through solid solution strengthening.
• the addition of an appropriate amount of Al suppresses the refinement of AlN that occurs when Al combines with N in the steel, and improves the crystallization during final annealing. It has the effect of improving grain growth.
• the Al content is set to 0.30% or more.
• the Al content is preferably set to 0.40% or more, and more preferably set to 0.
• the Al content is more than 45%, and even more preferable that the Al content is 0.50% or more.
• the Al content is set to 0.90% or less, preferably 0.80% or less, and more preferably 0.70% or less.
• the electrical resistance of the steel is ensured by appropriately controlling the contents of Si, Al, and Mn. Also, from the viewpoint of ensuring strength, it is necessary to appropriately control the contents of Si, Al, and Mn. On the other hand, from the viewpoint of ensuring magnetic flux density and toughness, an upper limit is also necessary. Therefore, in addition to the contents of Si, Al, and Mn being within the above ranges, it is necessary to satisfy the following formula (i).
• the value of the middle part of the following formula (i) is preferably 4.3 or more, more preferably 4.4 or more, preferably 4.8 or less, and more preferably 4.7 or less.
• P 0.030% or less
• P phosphorus
• the P content is set to 0.030% or less.
• the P content is preferably 0.025% or less, and more preferably 0.020% or less.
• the P content is preferably 0.003% or more, and more preferably 0.005% or more.
• S 0.0018% or less
• S sulfur
• the S content is preferably 0.0016% or less, and more preferably 0.0014% or less.
• the S content is preferably 0.0001% or more, more preferably 0.0003% or more, and even more preferably 0.0005% or more.
• N 0.0040% or less
• N nitrogen
• the N content is set to 0.0040% or less.
• the N content is preferably 0.0030% or less, and more preferably 0.0020% or less.
• the N content is preferably 0.0005% or more.
• Ti less than 0.0040%
• Ti titanium
• carbides, nitrides When carbides or nitrides are formed, these precipitates themselves deteriorate the magnetic properties of the non-oriented electrical steel sheet. Furthermore, they inhibit the growth of crystal grains during finish annealing, thereby deteriorating the magnetic properties of the non-oriented electrical steel sheet. Therefore, the Ti content is less than 0.0040%.
• the Ti content is preferably 0.0030% or less, and more preferably 0.0025% or less.
• the Ti content is preferably 0.0005% or more.
• Nb less than 0.0050%
• Nb niobium
• the Nb content is preferably 0.0040% or less, more preferably 0.0030% or less, and even more preferably 0.0020% or less.
• the Nb content is preferably 0.0001% or more.
• Zr less than 0.0050%
• Zr zirconium
• the Zr content is preferably 0.0040% or less, more preferably 0.0030% or less, and even more preferably 0.0020% or less.
• the Zr content is preferably 0.0001% or more.
• V less than 0.0050%
• V vanadium
• the V content is preferably 0.0040% or less, more preferably 0.0030% or less, and even more preferably 0.0020% or less.
• the V content is preferably 0.0001% or more.
• Cu less than 0.200%
• Cu (copper) is an element that is inevitably mixed into steel. Intentionally including Cu increases the manufacturing cost of the non-oriented electrical steel sheet. Therefore, in this embodiment, it is not necessary to actively include Cu, and it is sufficient to include Cu at the impurity level.
• the Cu content is less than 0.200%, which is the maximum value that can be unavoidably mixed in the manufacturing process.
• the Cu content is preferably 0.150% or less, and more preferably 0.100% or less.
• the lower limit of the Cu content is not particularly limited, but an extreme reduction in the Cu content may cause an increase in manufacturing costs. Therefore, the Cu content is preferably 0.001% or more, more preferably 0.003% or more, and even more preferably 0.005% or more.
• Ni less than 0.500%
• Ni nickel
• Ni is an element that is inevitably mixed into steel.
• Ni is also an element that improves the strength of non-oriented electrical steel sheets, so it may be intentionally contained.
• the Ni content is less than 0.500%.
• the Ni content is preferably 0.400% or less, and more preferably 0.300% or less.
• the lower limit of the Ni content is not particularly limited, but an extreme reduction in the Ni content may cause an increase in manufacturing costs. Therefore, the Ni content is preferably 0.001% or more, more preferably 0.003% or more, and even more preferably 0.005% or more.
• the Ni content is preferably 0.200% or more.
• Sn (tin) and Sb (antimony) have the effect of improving the texture and increasing the magnetic flux density of non-oriented electrical steel sheets. They are also useful elements for ensuring low iron loss in non-oriented electrical steel sheets by segregating to the surface of the base material and suppressing oxidation and nitridation during annealing.
• the total content of one or both of Sn and Sb is set to 0.005% or more.
• the total content is preferably 0.010% or more, more preferably 0.015% or more.
• the total content of one or both of Sn and Sb is set to 0.060% or less.
• the total content is preferably 0.050% or less, more preferably 0.040% or less.
• the balance is Fe and impurities.
• impurities refers to components that are mixed in due to various factors in the manufacturing process and raw materials such as ores and scraps when industrially manufacturing steel, and are acceptable within the range that does not adversely affect the present invention.
• the contents of Cr and Mo as impurity elements are not particularly specified.
• these elements are contained in the range of 0.5% or less, there is no particular effect on the properties of the non-oriented electrical steel sheet according to this embodiment.
• Ca and Mg are contained in the range of 0.002% or less, there is no particular effect on the properties of the non-oriented electrical steel sheet according to this embodiment.
• rare earth elements are contained in the range of 0.004% or less, there is no particular effect on the properties of the non-oriented electrical steel sheet according to this embodiment.
• REM refers to a total of 17 elements consisting of Sc, Y, and lanthanoids, and the above REM content refers to the total content of these elements.
• O is also an impurity element, but even if it is contained in a range of 0.035% or less, it does not affect the properties of the non-oriented electrical steel sheet according to this embodiment. Since O can be mixed into the steel during the annealing process, even if it is contained in a range of 0.010% or less at the slab stage (i.e., ladle value), there is no particular effect on the properties of the non-oriented electrical steel sheet according to this embodiment.
• impurity elements such as Zn, Pb, Bi, As, B, and Se may be included, but as long as the content of each is within the range of 0.0050% or less, the properties of the non-oriented electrical steel sheet according to this embodiment are not impaired.
• the chemical composition of the base material of the non-oriented electrical steel sheet according to this embodiment can be measured using various known methods. For example, it can be measured using ICP optical emission spectrometry, gravimetry, or spark discharge optical emission spectrometry.
• C and S can be measured using the combustion-infrared absorption method
• N can be measured using the inert gas combustion-thermal conductivity method
• O can be measured using the inert gas fusion-non-dispersive infrared absorption method.
• the average grain size of the base material is set to be more than 40 ⁇ m and not more than 140 ⁇ m.
• the average grain size of the base material is set to be more than 40 ⁇ m, it is possible to suppress the deterioration of hysteresis loss and improve magnetic properties.
• the average grain size is preferably 50 ⁇ m or more, more preferably 60 ⁇ m or more.
• the average grain size is preferably 130 ⁇ m or less, more preferably 120 ⁇ m or less.
• the average grain size of the base material is determined in accordance with JIS G 0551:2013 "Steel - Microscopic test method for grain size.”
• the concentration of ⁇ 111 ⁇ orientation is set to 4.0 or less. By suppressing the development of ⁇ 111 ⁇ orientation, it is possible to improve magnetic properties.
• the concentration of ⁇ 111 ⁇ orientation is preferably 3.8 or less, more preferably 3.6 or less. There is no need to set a lower limit for the concentration of ⁇ 111 ⁇ orientation, but 1.0 is a substantial lower limit.
• the degree of accumulation of the ⁇ 111 ⁇ orientation is measured by an X-ray diffraction device.
• the degree of accumulation is a value obtained by measuring the X-ray intensity of a standard sample that does not have accumulation in a specific orientation and the test material under the same conditions by X-ray diffraction, and dividing the X-ray intensity of the test material obtained by dividing the X-ray intensity of the standard sample by the X-ray intensity of the standard sample.
• the specific measurement method is as follows. The measurement was performed on the polished surface of the non-oriented electrical steel sheet of the test material, which was chemically polished to remove the base material from one side surface to a depth of 1/4 of the sheet thickness.
• the degree of accumulation of the ⁇ 111 ⁇ orientation is obtained from the crystal orientation distribution function ODF (Orientation Distribution Functions), which represents the three-dimensional texture, calculated by the series expansion method based on the pole figures of the ⁇ 200 ⁇ , ⁇ 110 ⁇ , ⁇ 310 ⁇ , and ⁇ 211 ⁇ planes of the ⁇ -Fe phase measured by an X-ray diffraction device.
• ODF Orientation Distribution Functions
• the ⁇ 111 ⁇ orientation may be further classified into the ⁇ 111 ⁇ 011> orientation and the ⁇ 111 ⁇ 112> orientation.
• Magnetic Properties in the non-oriented electrical steel sheet according to this embodiment excellent magnetic properties means low core loss W 10/400 and high magnetic flux density B 50 .
• the magnetic properties (iron loss W 10/400 and magnetic flux density B 50 ) are measured in accordance with the Epstein test method defined in JIS C 2550-1:2011.
• the density of the steel sheet is set to 7.65 g/cm 3 and the magnetic measurements are performed.
• the iron loss W 10/400 means the iron loss that occurs under the conditions of a maximum magnetic flux density of 1.0 T and a frequency of 400 Hz
• the magnetic flux density B 50 means the magnetic flux density in a magnetic field of 5000 A/m.
• low iron loss W10 /400 means 14.5 W/kg or less when the sheet thickness is 0.26 mm or more, 12.5 W/kg or less when the sheet thickness is 0.21 to 0.25 mm, and 11.2 W/kg or less when the sheet thickness is 0.20 mm or less.
• High magnetic flux density B50 means 1.64 T or more when the sheet thickness is 0.26 mm or more, 1.63 T or more when the sheet thickness is 0.21 to 0.25 mm, and 1.62 T or more when the sheet thickness is 0.20 mm or less.
• the non-oriented electrical steel sheet according to this embodiment has high strength.
• the tensile strength does not need to be particularly limited, but it is preferable that the tensile strength is 580 MPa or more. It is more preferable that the tensile strength is 590 MPa or more, and further more preferable that the tensile strength is 600 MPa or more.
• the tensile strength is measured by carrying out a tensile test in accordance with JIS Z 2241:2011.
• the sheet thickness of the base material is set to 0.10 mm or more from the viewpoint of manufacturing costs of cold rolling and finish annealing.
• the sheet thickness of the base material is set to 0.30 mm or less. Therefore, the sheet thickness of the base material of the non-oriented electrical steel sheet according to this embodiment is 0.10 to 0.30 mm.
• the sheet thickness of the base material is preferably 0.15 to 0.27 mm.
• the surface of the base material has an insulating coating. Since the non-oriented electrical steel sheet is used after being laminated after punching out a core blank, by providing an insulating coating on the surface of the base material, it is possible to reduce eddy currents between the sheets and reduce eddy current loss in the core.
• the type of insulating coating is not particularly limited, and known insulating coatings used as insulating coatings for non-oriented electrical steel sheets can be used.
• Examples of such insulating coatings include composite insulating coatings that are mainly made of inorganic substances and further contain organic substances.
• composite insulating coatings are insulating coatings that are mainly made of at least one of inorganic substances such as metal chromate salts, metal phosphate salts, colloidal silica, Zr compounds, and Ti compounds, and have fine organic resin particles dispersed therein.
• insulating coatings that use metal phosphate salts, coupling agents of Zr or Ti, or carbonates or ammonium salts of these as starting materials are preferably used.
• the amount of the insulating coating is not particularly limited, but is preferably about 200 to 3000 mg/ m2 per side, and more preferably 300 to 2500 mg/ m2 per side. By forming the insulating coating so that the amount of coating falls within the above range, it is possible to maintain excellent uniformity.
• various known measurement methods can be used, such as a method of measuring the mass difference before and after immersion in a sodium hydroxide aqueous solution, or a fluorescent X-ray method using a calibration curve method.
• the non-oriented electrical steel sheet according to this embodiment is not particularly limited in the manufacturing method, but can be manufactured by sequentially carrying out a hot rolling process, a hot-rolled sheet annealing process, a descaling process, a cold rolling process, and a finish annealing process on a steel ingot having the above-mentioned chemical composition under the conditions shown below, for example.
• a hot rolling process a hot-rolled sheet annealing process
• a descaling process a cold rolling process
• a finish annealing process on a steel ingot having the above-mentioned chemical composition under the conditions shown below, for example.
• an insulating coating is formed on the surface of the base material
• an insulating coating forming process is carried out after the above-mentioned finish annealing process.
• a steel ingot (slab) having the above chemical composition is heated and the heated steel ingot is hot rolled to obtain a hot rolled sheet.
• the heating temperature of the steel ingot when subjected to hot rolling is not particularly specified, but is preferably, for example, 1050 to 1250° C.
• the thickness of the hot rolled sheet after hot rolling is also not particularly specified, but is preferably, for example, about 1.5 to 3.0 mm, taking into account the final thickness of the base material.
• hot-rolled sheet annealing is performed for the purpose of reducing the iron loss of the steel sheet.
• hot-rolled sheet annealing is performed under conditions of a soaking temperature of 800 to 920 ° C and a soaking time of 1 second to 10 minutes.
• a soaking temperature 800 to 920 ° C and a soaking time of 1 second to 10 minutes.
• 820 ° C or higher is preferable.
• 900 ° C or lower is preferable.
• ⁇ Descaling process> The steel sheet after the above-mentioned hot-rolled sheet annealing is subjected to shot blasting and then pickling to remove the scale layer formed on the surface of the base material. Since a scale layer develops during hot-rolled sheet annealing, by performing shot blasting before pickling, descaling by the subsequent pickling becomes easier.
• pickling conditions such as the concentration of the acid used in pickling, the concentration of the accelerator used in pickling, and the temperature of the pickling solution are not particularly limited, and may be known pickling conditions.
• finish annealing is performed.
• a continuous annealing furnace for the finish annealing.
• the finish annealing is performed under the conditions of a soaking temperature of 900 to 1050°C and a soaking time of 1 second to 10 minutes.
• the soaking temperature is less than 900°C, the crystal grain size becomes fine and the iron loss deteriorates, which is undesirable, and if the soaking temperature exceeds 1050°C, the strength becomes insufficient and the iron loss also deteriorates, which is undesirable. Also, if the soaking time is less than 1 second, the crystal grains cannot grow sufficiently. On the other hand, if the soaking time exceeds 10 minutes, it will cause an increase in manufacturing costs.
• the material is heated to a temperature of 850°C or higher so that the heating rate in the temperature range of 500 to 850°C is 400°C/s or higher.
• the heating rate is preferably 800°C/s or more, and more preferably 1000°C or more.
• the magnetic properties can be improved by performing rapid heating to a temperature of 850°C or more.
• the average heating rate may be 1 to 2000°C/s for the entire heating process, including the temperature range below 500°C and the soaking temperature.
• an insulating film forming step is carried out as necessary.
• the method for forming the insulating film is not particularly limited, and the following known insulating film forming methods are available:
• the treatment liquid may be applied and dried by a known method using the treatment liquid.
• Known examples of the insulating coating include composite insulating coatings that are mainly made of an inorganic material and further contain an organic material.
• a composite insulating coating is, for example, an insulating coating that is mainly composed of at least one of metal salts such as metal chromate salts and metal phosphate salts, or inorganic substances such as colloidal silica, Zr compounds, and Ti compounds, with fine organic resin particles dispersed in it.
• metal salts such as metal chromate salts and metal phosphate salts
• inorganic substances such as colloidal silica, Zr compounds, and Ti compounds, with fine organic resin particles dispersed in it.
• insulating coatings that use metal phosphate salts, Zr or Ti coupling agents as starting materials are preferably used.
• the surface of the base material on which the insulating coating is to be formed may be subjected to any pretreatment, such as degreasing with an alkali or pickling with hydrochloric acid, sulfuric acid, phosphoric acid, etc., before the treatment liquid is applied.
• the treatment liquid may also be applied to the surface of the base material as is after finish annealing without performing these pretreatments.
• the non-oriented electrical steel sheet of the present invention obtained as described above has excellent properties such as low iron loss, high magnetic flux density, and high strength, making it suitable as a material for both rotor cores and stators.
• a slab having the chemical composition shown in Table 1 was heated to 1150°C, then hot rolled at a finishing temperature of 850°C and a finishing thickness of 2.0 mm, and coiled at 600°C to produce hot-rolled steel sheet.
• the resulting hot-rolled steel sheet was hot-rolled in a continuous annealing furnace under the conditions shown in Table 2.
• the steel sheet thus obtained was descaled by shot blasting and pickling, and then cold-rolled to produce cold-rolled steel sheet with the thickness shown in Table 2.
• the steel sheet was subjected to finish annealing under the conditions shown in Table 2 in a mixed atmosphere of H 2 : 20%, N 2 : 80%, and a dew point of -30°C.
• Induction heating was used for heating during the finish annealing, and the steel sheet was rapidly heated to the final temperature shown in Table 2.
• the heating process from the final temperature to the soaking temperature and the soaking process were performed by heating using a radiant tube.
• the heating rate from the final temperature to the soaking temperature was about 5°C/s.
• An insulating coating made of aluminum phosphate and an acrylic-styrene copolymer resin emulsion with a particle size of 0.2 ⁇ m was applied to the steel sheet after the finish annealing, and the coating was baked in air at 350°C.
• the average grain size of the base material was measured according to JIS G 0551:2013 "Steel-Microscopic Test Method for Grain Size".
• Epstein test pieces were taken from the rolling direction and width direction of each test material, and the core loss W 10/400 and magnetic flux density B 50 were evaluated by the Epstein test according to JIS C 2550-1:2011. Note that the density of the steel sheet was set to 7.65 g/cm 3 , and magnetic measurements were performed.
• the parent material of each test material was removed from one surface to a depth of 1/4 of the plate thickness by chemical polishing, and the degree of concentration of the ⁇ 111 ⁇ orientation on the polished surface was determined from the crystal orientation distribution function ODF (Orientation Distribution Functions), which represents the three-dimensional texture, calculated by the series expansion method based on the pole figures of the ⁇ 200 ⁇ , ⁇ 110 ⁇ , ⁇ 310 ⁇ , and ⁇ 211 ⁇ planes of the ⁇ -Fe phase measured by an X-ray diffraction device.
• ODF Orientation Distribution Functions
• JIS No. 5 tensile test specimens were taken from each test material in accordance with JIS Z 2241:2011, with the longitudinal direction coinciding with the rolling direction of the steel plate. Tensile tests were then conducted in accordance with JIS Z 2241:2011 using the test specimens to measure the tensile strength.
• test No. 1 the heating rate during final annealing was lower than the specified range, so the concentration of the ⁇ 111 ⁇ orientation exceeded the specified range, resulting in poor magnetic flux density.
• test No. 4 the temperature reached by rapid heating during final annealing was lower than the specified range, so the concentration of the ⁇ 111 ⁇ orientation exceeded the specified range, resulting in poor magnetic flux density.
• test No. 7 the plate thickness was thicker than the specified range, resulting in poor iron loss.
• the S content was higher than the specified range, resulting in a large amount of MnS precipitation and poor iron loss.
• test No. 10 the total Sn and Sb content was lower than the specified range, resulting in the concentration of ⁇ 111 ⁇ orientation exceeding the specified range and poor magnetic flux density.
• test No. 11 the total Sn and Sb content was higher than the specified range, resulting in poor toughness and fracture during cold rolling, making it impossible to measure tensile strength and magnetic properties.
• test No. 18 the Si content was lower than the specified range, resulting in poor tensile strength.
• test No. 19 the Si content was higher than the specified range, resulting in poor toughness and fracture during cold rolling, making it impossible to measure tensile strength and magnetic properties.
• the Al content was lower than the specified range, resulting in the average crystal grain size after finish annealing being smaller than the specified range and poor iron loss.
• test No. 21 the soaking temperature during hot-rolled sheet annealing was lower than the specified range, so the concentration of the ⁇ 111 ⁇ orientation exceeded the specified range, resulting in poor magnetic flux density.
• test No. 23 the soaking temperature during hot-rolled sheet annealing was higher than the specified range, so toughness deteriorated and the specimen broke during cold rolling, making it impossible to measure tensile strength and magnetic properties.
• test No. 24 the Al content was higher than the specified range, so toughness deteriorated and the specimen broke during cold rolling, making it impossible to measure tensile strength and magnetic properties.
• test No. 26 the soaking temperature in the final annealing was lower than the specified range, the average crystal grain size was smaller than the specified range, and the iron loss was poor.
• test No. 29 the soaking temperature in the final annealing was higher than the specified range, the average crystal grain size was larger than the specified range, and the tensile strength was poor.
• non-oriented electrical steel sheets with excellent magnetic properties and high strength can be obtained stably at low cost.

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