US20200318215A1 - Steel sheet for shielding magnetic field and method for manufacturing same - Google Patents

Steel sheet for shielding magnetic field and method for manufacturing same Download PDF

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US20200318215A1
US20200318215A1 US16/955,562 US201816955562A US2020318215A1 US 20200318215 A1 US20200318215 A1 US 20200318215A1 US 201816955562 A US201816955562 A US 201816955562A US 2020318215 A1 US2020318215 A1 US 2020318215A1
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steel sheet
magnetic field
shielding magnetic
temperature
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Tae-Il So
Ho-Kyung SHIM
Chon-Kue KIM
Jong-In Choi
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Posco Holdings Inc
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Posco Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • 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
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0073—Shielding materials
    • 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
    • C21D1/26—Methods of annealing
    • C21D1/28—Normalising
    • 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 by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—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 by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/12—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
    • 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
    • H01F1/032—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 hard-magnetic materials
    • H01F1/10—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 hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure
    • H01F1/11—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 hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure in the form of particles
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/36—Electric or magnetic shields or screens
    • H01F27/366—Electric or magnetic shields or screens made of ferromagnetic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F3/00—Cores, Yokes, or armatures
    • H01F3/02—Cores, Yokes, or armatures made from sheets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0206—Manufacturing of magnetic cores by mechanical means
    • H01F41/0233—Manufacturing of magnetic circuits made from sheets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0266—Moulding; Pressing
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0073—Shielding materials
    • H05K9/0075—Magnetic shielding materials
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/004—Dispersions; Precipitations
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite

Definitions

  • the present disclosure relates to a steel sheet for shielding a magnetic field used in a medical magnetic resonance imaging (MRI) room wall, or the like, and a method for manufacturing the same.
  • MRI magnetic resonance imaging
  • a magnetic resonance imaging (MRI) device mainly used in hospitals is a device applying radio waves to a human body located within a strong magnetic field and measuring the reflected magnetic field to observe brains, internal organs, and other internal organs.
  • the MRI device utilizes a superconducting magnet to generate a static magnetic field, and there have recently been high magnetic field MRI devices of 7 T (T: Tesla) or higher developed to obtain high-resolution images.
  • permeability characteristics indicating a high magnetic flux density according to a specific magnetic field intensity in a material are important in shielding a DC magnetic field, and it is necessary to have a low coercive force.
  • precipitates such as carbon, nitrogen, carbides or nitrides in steel, which hinder movements of a magnetic domain wall, should be minimized, and grain growth should be promoted while reducing grain boundaries.
  • An addition of impurities to steel forms finely dispersed precipitates during solidification or during a heat treatment process after rolling, thereby forming a new magnetic domain which reduces static magnetic energy and intervenes movements of the magnetic domain wall.
  • the intrusive element reduces permeability by elastically deforming a lattice of a solid solution, and carbon is a representative element.
  • Patent Document 1 has proposed a hot-rolled pickled thick steel sheet having excellent magnetic field shielding characteristics; however, the steel sheet of Patent Document 1 is different from that of the present disclosure in that it lacks magnetic shielding performance because magnetic characteristics are only provided by hot-rolling, coiling and pickling without a heat treatment and is a material for shielding an AC magnetic fields. Recently, there is increasing demand for steel materials having excellent magnetic shielding ability capable of shielding a DC magnetic field such as an MRI room. (Patent Document 1) Korea Patent Publication No. 10-2005-0129244
  • An aspect of the present disclosure is to provide a steel sheet having excellent magnetic field shielding performance by controlling alloying elements and heat treatment conditions, and a method for manufacturing the same.
  • An aspect of the present disclosure relates to a steel sheet for shielding magnetic field, comprising, by weight %, 0.02% or less of carbon (C), 0.001% to 0.05% of silicon (Si), 0.01% to 0.2% of manganese (Mn), 0.001% or 0.05% of aluminum (Al), 0.005% or less niobium (Nb), 0.07% or less of titanium (Ti), 0.01% or less of nitrogen (N), 0.015% or less of phosphorus (P), 0.005% or less of sulfur (S), and a remainder of iron (Fe) and inevitable impurities, wherein a microstructure has ferrite as main structure, wherein the ferrite has an average grain size of 100 ⁇ m or greater.
  • An another aspect relates to a method for manufacturing a steel sheet for shielding magnetic field, including reheating a steel slab comprising by weight %, 0.02% or less of carbon (C), 0.001% to 0.05% of silicon (Si), 0.01% to 0.2% of manganese (Mn), 0.001% or 0.05% of aluminum (Al), 0.005% or less niobium (Nb), 0.07% or less of titanium (Ti), 0.01% or less of nitrogen (N), 0.015% or less of phosphorus (P), 0.005% or less of sulfur (S), and a remainder of iron (Fe) and inevitable impurities at a temperature of Ac3 to 1250° C., hot rolling the reheated slab and finish hot rolling at a temperature of Ar3 or higher to obtain a steel sheet; and air cooling the steel sheet to room temperature.
  • C carbon
  • Si silicon
  • Mn manganese
  • Al aluminum
  • Nb niobium
  • Ti titanium
  • N nitrogen
  • P phosphorus
  • the present disclosure can provide a steel sheet having excellent magnetic field shielding performance, capable of suppressing an impact on the human body and external electronic devices when applying a DC magnetic field and applying the DC magnetic field from an MRI device to outside of an MRI room by enabling smooth movements of magnetic domains.
  • FIG. 1 is a graph illustrating magnetic flux density according to magnetic field intensity of Inventive Examples 2, 5 and 7 and Comparative Example 2.
  • FIG. 2 is a graph illustrating relative permeability according to the magnetic flux density of Inventive Examples 2, 5 and 7 and Comparative Example 2.
  • the present inventors conducted extensive research on the above technical problems, and as a result, controlled alloying elements and a manufacturing process to improve shielding performance of a DC magnetic field to coarse grains and facilitate smooth movements of a magnetic domain when the DC magnetic field is applied, thereby providing a steel material having a size of 15 mmt capable of preventing the DC magnetic field released from hospital MRI devices being applied to the outside an MRI room and affecting the human body and external electronic devices.
  • the steel sheet of the present disclosure may contain, by weight % (hereinafter, “%”), 0.02% or less of carbon (C), 0.001% to 0.05% of silicon (Si), 0.01% to 0.2% of manganese (Mn), 0.001% or 0.05% of aluminum (Al), 0.005% or less of niobium (Nb), 0.07% or less of titanium (Ti), 0.01% or less of nitrogen (N), 0.015% or less of phosphorus (P), 0.005% or less of sulfur (S), and a remainder of iron (Fe) and inevitable impurities.
  • C is preferably contained of 0.02% or less, more preferably 0.005% or less.
  • Silicon (Si) is mainly used as a deoxidizer. When Si is contained, solubility of C is reduced, thereby lowering magnetic field shielding characteristics. In this regard, it is preferable to contain 0.05% or less. However, Si less than 0.001% results in insufficient deoxidization. Accordingly, an amount of Si is preferably 0.001% to 0.05%, more preferably 0.001% to 0.05%.
  • Manganese (Mn) is an element binding to S to form MnS, which is a factor itself increasing brittleness. In order to reduce the brittleness due to S, it is preferable to contain 0.01% or more. However, since MnS formed at a grain boundary during high temperature heat treatment suppress grain coarsening, it is preferable that an amount of Mn not exceed 0.2%.
  • Aluminum (Al) is an element for deoxidizing molten steel inexpensively. To sufficiently obtain such an effect, it is preferable to contain 0.001% or more. In the case of an amount exceeding 0.05%, however, Al binds to N to form AlN, thereby suppressing grain coarsening. In this regard, it is preferable to contain Al in an amount of 0.05% or less.
  • Niobium (Nb) is an element precipitated in the form of NbC or Nb(C,N) to significantly improve strength of a base material and a weld zone. Further, Nb employed during reheating at a high temperature suppresses recrystallization of austenite and transformation of ferrite or bainite thereby refine a structure. In this regard, Nb is an element added to secure strength of a conventional hot rolled steel sheet. Meanwhile, Nb has an adverse effect on magnetic shielding characteristics due to grain refinement, and thus, it is preferable that 0.005% or less of Nb be contained.
  • Titanium (Ti) has an effect of inhibiting grain growth as a result of reacting mainly with nitrogen when heated and thus is preferable to be added to a conventional carbon steel to improve strength and toughness.
  • Ti is a detrimental element ingrain coarsening, it is preferable to contain Ti in an amount of 0.07% or less.
  • Nitrogen (N) is an element forming TiN when simultaneously added with Ti and forming AlN by binding to Al when Ti is not added.
  • TiN, AlN, or the like is formed at a grain boundary or within a grain, grain coarsening is suppressed during heat treatment at a high temperature.
  • N is preferably contained in an amount of 0.01% (100 ppm) or less, more preferably 0.005% (50 ppm) or less.
  • Phosphorus (P) is an element advantageous in improving strength and corrosion resistance but may significantly increase brittleness of a material. In this regard, it is desirable that an amount thereof be managed to be as low as possible. Accordingly, it is preferable that the amount of P be 0.015% or less.
  • S Sulfur
  • MnS MnS
  • an amount of S be 0.005% or less.
  • the steel sheet of the present disclosure contains iron (Fe) in addition to the above mentioned alloy elements.
  • Fe iron
  • undesired impurities may be inevitably incorporated from an environment or a raw material during a conventional manufacturing process and thus cannot be excluded.
  • Such impurities are known to any one of ordinary skill in the art, and will thus not be mentioned in detail.
  • the steel sheet of the present disclosure has a main structure of ferrite and preferably contains 95 area % or more of ferrite, more preferably 99 area % or more.
  • an average grain size of the ferrite be 100 ⁇ m or greater.
  • the grain size is less than 100 ⁇ m after hot rolling, air cooling, normalizing heat treatment, and stress relief annealing, a movement of a magnetic domain is not smooth so that a magnetic flux density is not sufficiently high when a magnetic field is induced on a shielding steel sheet. Thereby, a shielding effect is not sufficient when a DC magnetic field is applied to an MRI of 7 T or higher.
  • the steel sheet of the present disclosure may contain precipitates at a grain boundary or within a grain of the ferrite.
  • the precipitates may be AlN, TiN, MnS, or the like.
  • a maximum size of the precipitate not exceed 100 nm, more preferably 20 nm.
  • the steel sheet has yield strength of 190 MPa or less, tensile strength of 220 MPa to 300 MPa, elongation of 40% or more, and a yield ratio of 0.8 or less.
  • the steel sheet of the prevent disclosure is preferably has a magnetic flux density of 1 T (Tesla) or higher under magnetic field intensity of 300 A/m, more preferably 1.3 T or higher for better DC magnetic field shielding performance.
  • the steel sheet of the present disclosure may be manufactured by heating a steel material (a steel slab) satisfying the alloy composition described above and hot rolling. If necessary, stress relief annealing may be performed, in addition to a normalizing heat treatment. Each process will be described in detail.
  • a steel material satisfying the previously described alloy composition a steel slab, is prepared and heated.
  • the heating is preferably performed in the temperature range of Ac3 to 1250° C.
  • the Ac3 can be calculated using Equation 1 below.
  • the heating temperature of the steel slab is less than Ac3, transformation of austenite to ferrite is initiated during rolling, thereby adversely affecting magnetic characteristics due to refinement of grain size of ferrite. Meanwhile, it is preferable that the heating be performed at a temperature not exceeding 1250° C. in consideration of economical feasibility.
  • Each component symbol refers to a content thereof (wt %).
  • the heated steel material is hot rolled.
  • the hot rolling process specifically involves rough rolling of the reheated slab and finish rolling to obtain a hot rolled steel sheet.
  • the rough rolling is preferably performed in the temperature range of Tnr to 1250° C.
  • Tnr can be derived from Equation 2 below.
  • Each component symbol refers to a content thereof (wt %).
  • the finish rolling when the finish rolling is performed in a temperature range below Ar3, at which the austenite begins to transform to ferrite, refined ferrite forms nuclei at a ferrite grain boundary, thereby reducing an average grain size so that adversely affecting magnetic characteristics. Accordingly, it is preferable that the finish rolling be performed at a temperature of Ar3 or higher.
  • Hot rolled steel sheet is then cooled.
  • the cooling is not particularly managed.
  • air cooling is performed, the air cooling is performed until the temperature reaches room temperature.
  • the cooled steel sheet is normalizing heat treated of maintaining at a temperature of Ac3 or higher for (1.3t+30) minutes, and then, furnace cooling or air cooling.
  • the normalizing heat treatment performed for a long period of time at a temperature of Ar3 or higher is effective in improving magnetic shielding characteristics due to additional grain coarsening. It requires at least (1.3t, t: thickness) minutes to allow an thick steel plate to reach a target temperature, and at least 30 minutes of maintaining after the target temperature is reached to distribute a uniform temperature from a surface of the steel sheet to a center thereof.
  • stress relief annealing of heat treating at 800° C. to 900° C. for (1.3t+30) minutes, and then, furnace cooling may be performed. Stress remaining in the hot rolled steel sheet, which has been rough rolled and finish rolled, may interfere movements of the magnetic domain and significantly reduce the magnetic characteristics.
  • stress relief annealing of heat treating at 800° C. to 900° C. for (1.3t+30, t: thickness of steel sheet) minutes after the normalizing heat treatment, and then air cooling or furnace cooling may be additionally performed to maximize the magnetic shielding characteristics.
  • a steel slab having a thickness of 300 mm and the composition of Table 1 is prepared, and a sheet material is manufactured under the condition of Table 2 below.
  • a unit of the alloy composition of Table 1 is wt %, and a remainder of iron (Fe) and inevitable impurities are included.
  • a grain size and mechanical properties were evaluated and indicated in Table 3 below.
  • the grain size was observed in a thickness direction of the steel sheet using an optical microscope.
  • the mechanical properties such as yield strength, tensile strength, elongation, and the like, were evaluated using a tensile tester by taking a full thickness sample in a rolling direction at room temperature.
  • Inventive Examples satisfying the alloy composition and manufacturing process of the present disclosure have a grain size of 100 ⁇ m or greater, yield strength of 190 MPa or less, tensile strength of 220 MPa to 300 MPa, elongation of 40% or more, and a yield ratio of 0.8 or less.
  • Comparative Examples 1 and 2 employs a steel containing C in an amount exceeding the amount suggested in the present disclosure, so that they contain grains having a refined size as compared to those of Inventive Examples 1 to 7, and thus have yield strength and tensile strength beyond the ranges suggested in the present disclosure due to grain refinement.
  • Comparative Example 3 has a composition satisfying the range suggested in the present disclosure, however, a thickness of a final product after hot rolling the slab is small (a total reduction amount is increased), which is beyond the strength range suggested in the present disclosure.
  • Inventive Examples 1 to 7 satisfying the alloy composition and manufacturing method of the present disclosure have a magnetic flux density of 1.0 T or higher at magnetic field intensity of B3.
  • Inventive Example 3 among all Inventive Examples, does not involve additional normalizing heat treatment after hot rolling and cooling and showed relative lower values as compared to Inventive Examples 1 and 2, which are in similar conditions.
  • Inventive Example 7 is a result of performing stress relief annealing and thus has a highest excellent magnetic flux density compared to the other conditions.
  • Comparative Examples 1 to 3 have a magnetic flux density of 0.11 T to 0.98 T at magnetic field intensity of B3, indicating inappropriateness to be used as a material for an MRI shielding room of 7 T or higher.
  • FIG. 1 is a graph illustrating magnetic flux density according to magnetic field intensity of Inventive Examples 2, 5 and 7 and Comparative Example 2.
  • the magnetic flux density was found to be high in the order of Examples 7, 2, and 5, while Comparative Example 2 showed a lowest magnetic flux density. It can be seen that the magnetic characteristics are the highest when the stress relief annealing and normalizing heat treatment are performed after hot rolling and the composition and components suggested in the present disclosure are satisfied.
  • FIG. 2 is a graph illustrating relative permeability according to the magnetic flux density of Inventive Examples 2, 5 and 7 and Comparative Example 2.
  • Permeability is a value indicating a degree of magnetization of a medium in a given magnetic field
  • relative permeability indicates a ratio of permeability of a medium to vacuum permeability and is represented as the equation “magnetic flux density/magnetic field intensity/1.257.”
  • the relative permeability of FIG. 2 illustrates a result of each sample indicated in FIG. 1 calculated using the equation with respect to the magnetic flux density.
  • the graph indicates that a higher relative magnetic permeability enables easier magnetization of a shielding material when a magnetic field is applied and more effective shielding performance.

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102022111444A1 (de) 2022-05-09 2023-11-09 Thyssenkrupp Steel Europe Ag Verwendung eines Kohlenstoffstahlblechs für elektromagnetische Abschirmzwecke

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102255829B1 (ko) * 2019-12-16 2021-05-25 주식회사 포스코 충격인성이 우수한 제진 댐퍼용 강재 및 이의 제조방법

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005281806A (ja) * 2004-03-30 2005-10-13 Jfe Steel Kk 靭性に優れた低降伏点鋼材とその製造方法
JP2008248290A (ja) * 2007-03-29 2008-10-16 Nippon Steel Corp 靭性に優れたダンパー用低降伏点鋼およびその製造方法

Family Cites Families (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2682144B2 (ja) * 1988-10-24 1997-11-26 日本鋼管株式会社 軟磁性鋼材の製造方法
JPH0696745B2 (ja) * 1988-06-30 1994-11-30 日本鋼管株式会社 軟質磁性材料の製造方法
JPH0266119A (ja) * 1988-08-31 1990-03-06 Nkk Corp 磁気シールド特性に優れた高透磁率軟磁性純鉄板の製造方法
US5019191A (en) * 1988-12-22 1991-05-28 Sumitomo Metal Industries, Ltd. Magnetic steel plate for use as a magnetic shielding member and a method for the manufacture thereof
JP2679258B2 (ja) * 1989-06-17 1997-11-19 日本鋼管株式会社 鉄基軟磁性鋼材
JPH0613747B2 (ja) * 1989-09-07 1994-02-23 住友金属工業株式会社 磁気シールド用電磁鋼板およびその製造方法
JP2503110B2 (ja) * 1991-02-20 1996-06-05 新日本製鐵株式会社 磁気特性の優れた無方向性電磁厚板の製造方法
JPH05186855A (ja) * 1991-06-26 1993-07-27 Nippon Steel Corp 磁気特性に優れた無方向性電磁鋼板およびその製造方法
JP3162782B2 (ja) * 1992-03-05 2001-05-08 川崎製鉄株式会社 磁気特性の優れた軟磁性鉄板及びその製造方法
KR0129244B1 (ko) 1994-07-08 1998-04-08 구자홍 공조기
JPH09157743A (ja) * 1995-12-08 1997-06-17 Sumitomo Metal Ind Ltd 磁気シールド用電磁鋼板とその製造方法
CN1078625C (zh) * 1997-11-05 2002-01-30 新日本制铁株式会社 地磁屏蔽特性优良的高强度冷轧钢板及其制造方法
JP3692222B2 (ja) * 1997-11-05 2005-09-07 新日本製鐵株式会社 地磁気シールド特性の良好な高強度冷延鋼板および高強度めっき鋼板とその製造方法
JP4047502B2 (ja) * 1999-10-14 2008-02-13 新日本製鐵株式会社 磁気シールド構造用鋼板およびその製造方法
JP4174320B2 (ja) * 2000-12-19 2008-10-29 ポスコ 優れた電気及び磁気シールド特性を有する高強度の鋼板及びその製造方法
KR100490989B1 (ko) * 2000-12-19 2005-05-24 주식회사 포스코 수산화마그네슘이 포함된 고효율 원적외선 방사 분말
JP2003147488A (ja) * 2001-11-06 2003-05-21 Kawasaki Steel Corp 磁気シールド用極厚鋼板及びその製造方法
KR20040041454A (ko) * 2002-11-11 2004-05-17 주식회사 포스코 자기차폐성이 우수한 음극선관용 이너쉴드 냉연강판의제조방법
JP2005150130A (ja) * 2003-11-11 2005-06-09 Nippon Steel Corp 電磁波吸収作用をもつ電磁鋼板
KR100638043B1 (ko) * 2004-10-04 2006-10-23 동부제강주식회사 자기차폐성 및 가공성이 뛰어난 브라운관의 인너실드용 고투자율강판 및 그 제조방법
JP4779474B2 (ja) * 2005-07-07 2011-09-28 住友金属工業株式会社 回転子用無方向性電磁鋼板およびその製造方法
JP4853392B2 (ja) * 2007-06-12 2012-01-11 住友金属工業株式会社 回転子用無方向性電磁鋼板およびその製造方法
KR101185289B1 (ko) * 2010-08-30 2012-09-21 현대제철 주식회사 용접부 저온 인성이 우수한 고강도 강판 및 그 제조 방법
US20150211088A1 (en) * 2011-12-23 2015-07-30 Posco Non-magnetic high manganese steel sheet with high strength and manufacturing method thereof
KR101359109B1 (ko) * 2011-12-28 2014-02-06 주식회사 포스코 황화물 응력균열 저항성 및 저온인성이 우수한 압력용기용 강재 및 그 제조방법
JP6110097B2 (ja) * 2012-03-30 2017-04-05 日新製鋼株式会社 高出力リラクタンスモータ鉄心用鋼板とその製造方法、これを素材とするリラクタンスモータ用ロータ、ステータおよびリラクタンスモータ
JP2017002392A (ja) * 2015-06-12 2017-01-05 株式会社神戸製鋼所 軟磁性鋼板
CN106399854B (zh) * 2016-06-23 2018-10-02 宝山钢铁股份有限公司 抗应力腐蚀开裂优良的高锰非磁性钢板及其制造方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005281806A (ja) * 2004-03-30 2005-10-13 Jfe Steel Kk 靭性に優れた低降伏点鋼材とその製造方法
JP2008248290A (ja) * 2007-03-29 2008-10-16 Nippon Steel Corp 靭性に優れたダンパー用低降伏点鋼およびその製造方法

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
ARAKI K, JP 2005281806 A machine translation, 2005-10-13 (Year: 2005) *
UEMORI R, JP-2008248290-A machine translation, 2008-10-16 (Year: 2008) *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102022111444A1 (de) 2022-05-09 2023-11-09 Thyssenkrupp Steel Europe Ag Verwendung eines Kohlenstoffstahlblechs für elektromagnetische Abschirmzwecke

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