WO2024095595A1 - Feuille d'acier électromagnétique non orientée et son procédé de production - Google Patents

Feuille d'acier électromagnétique non orientée et son procédé de production Download PDF

Info

Publication number
WO2024095595A1
WO2024095595A1 PCT/JP2023/031961 JP2023031961W WO2024095595A1 WO 2024095595 A1 WO2024095595 A1 WO 2024095595A1 JP 2023031961 W JP2023031961 W JP 2023031961W WO 2024095595 A1 WO2024095595 A1 WO 2024095595A1
Authority
WO
WIPO (PCT)
Prior art keywords
steel sheet
less
group
total
mass
Prior art date
Application number
PCT/JP2023/031961
Other languages
English (en)
Japanese (ja)
Inventor
善彰 財前
智幸 大久保
勇人 齋藤
孝明 田中
龍一 末廣
Original Assignee
Ｊｆｅスチール株式会社
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
Application filed by Ｊｆｅスチール株式会社 filed Critical Ｊｆｅスチール株式会社
Publication of WO2024095595A1 publication Critical patent/WO2024095595A1/fr

Links

Images

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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • 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
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • 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

Definitions

  • the present invention relates to a non-oriented electrical steel sheet with excellent magnetic properties and a method for manufacturing the same.
  • HEVs hybrid electric vehicles
  • EVs electric vehicles
  • FCEVs fuel cell vehicles
  • the above motors have been improving in both efficiency and power output, and for EV motors that do not have internal combustion engines such as engines, there is a growing demand for higher motor power output.
  • Non-oriented electromagnetic steel sheets are often used as the iron core material for the drive motors of these EVs, and there is a strong demand for these steel sheets to have low iron loss in the high magnetic flux density range in order to achieve high motor power and high efficiency.
  • non-oriented electrical steel sheets have been designed to reduce iron loss by adding alloying elements such as Si and Al to increase resistivity or by reducing the sheet thickness to reduce eddy current loss.
  • alloying elements such as Si and Al to increase resistivity or by reducing the sheet thickness to reduce eddy current loss.
  • adding a large amount of alloying elements reduces saturation magnetic flux density, even if it can reduce iron loss.
  • the reduction in magnetic flux density increases copper loss in the motor, which leads to reduced motor efficiency.
  • reducing the sheet thickness requires reducing the thickness of the hot-rolled steel sheet or increasing the cold rolling reduction rate, which leads to reduced productivity. Therefore, if a non-oriented electrical steel sheet that has low core loss in the high magnetic flux density range could be developed without reducing the magnetic flux density or reducing productivity, it would be expected to greatly contribute to the miniaturization and efficiency improvement of electrical equipment.
  • Patent Document 1 discloses a method in which P is added to control the crystal orientation (texture) of the steel, thereby increasing the magnetic flux density and achieving low iron loss in the high magnetic flux density range.
  • Patent Document 1 since P is an element that segregates at grain boundaries and causes embrittlement of steel, the technology disclosed in Patent Document 1 cannot stably obtain low iron loss in the high magnetic flux density range and cannot fully meet the current demands for non-oriented electrical steel sheets.
  • the present invention was made in consideration of the above problems with the conventional technology, and its purpose is to provide a non-oriented electrical steel sheet with low core loss in the high magnetic flux density range without causing a decrease in magnetic flux density or productivity, and to propose an advantageous manufacturing method for the same.
  • the inventors conducted extensive research focusing on the effect of the surface condition on the magnetic properties of non-oriented electrical steel sheet. Specifically, the Co content in the steel was controlled within a specified range, and the steel sheet before final annealing was subjected to an electrolytic alkaline degreasing treatment (hereinafter referred to as "electrolytic degreasing treatment”, “electrolytic alkaline treatment”, or “alkali treatment”) under specified conditions, and then final annealing was performed at a low dew point of -70 to -10°C, controlling the amount of nitrogen in the surface layer within a specified range.
  • electrolytic degreasing treatment electrolytic alkaline degreasing treatment
  • electrolytic alkaline treatment electrolytic alkaline treatment
  • alkali treatment electrolytic alkaline treatment
  • the non-oriented electrical steel sheet according to the present invention which is based on the above findings, is configured as follows. [1] In mass%, it contains C: 0.0050% or less, Si: 2.0 to 6.5%, Mn: 0.05 to 2.00%, P: 0.10% or less, S: 0.0050% or less, Al: 0.3 to 2.0%, N: 0.0010% to 0.0050%, Co: 0.0010 to 0.010%, Ti: 0.0030% or less, Nb: 0.0030% or less, O: 0.0050% or less, and the balance is Fe and unavoidable impurities, and has a component composition consisting of and a nitrogen content Nc at a center portion of the steel sheet thickness and the nitrogen content Nc at the surface of the steel sheet and the nitrogen content Nc at the surface layer of the steel sheet satisfy the following formula (1): and the iron loss of the steel sheet excited at 50 Hz and 1.7 T is 3.2 W/kg or less.
  • the steel sheet is a non-oriented electrical steel sheet further containing, in addition to the above-mentioned chemical composition, one or more components selected from the following groups A to C: In the above weight percent, Group A: One or two selected from Sn: 0.005-0.20%, Sb: 0.005-0.20% Group B: One or more selected from Cu, Ni and Cr: 0.03-1.0% in total Group C: one or more selected from Ca, Mg and REM: 0.0005 to 0.020% in total [4] In the above [1] to [3], the steel sheet is a non-oriented electrical steel sheet containing, in addition to the above-mentioned chemical composition, one or more components selected from the following groups D to G.
  • Group D one or two selected from Ge and Ga: 0.0005 to 0.01% in total
  • E group Zn: 0.001-0.05%
  • F group one or more selected from Mo
  • As and W 0.001 to 0.05% in total
  • Group G one or more selected from B, Pb and V: 0.0001 to 0.01% in total
  • a method for producing a non-oriented electrical steel sheet according to the present invention based on the above findings is configured as follows. [5] A composition containing, by mass%, C: 0.0050% or less, Si: 2.0 to 6.5%, Mn: 0.05 to 2.00%, P: 0.10% or less, S: 0.0050% or less, Al: 0.3 to 2.0%, N: 0.0010 to 0.0050%, Co: 0.0010 to 0.010%, Ti: 0.0030% or less, Nb: 0.0030% or less, O: 0.0050% or less, with the balance being Fe and unavoidable impurities.
  • the method for producing a non-oriented electrical steel sheet includes a hot rolling step of hot rolling a steel slab having a structural composition to obtain a hot-rolled sheet, a cold rolling step of annealing the hot-rolled sheet or, without annealing, performing one cold rolling or two or more cold rolling steps with intermediate annealing in between to obtain a cold-rolled sheet, an electrolytic degreasing step of electrolytically degreasing the cold-rolled sheet, and a finish annealing step of finish annealing the electrolytically degreased cold-rolled sheet, wherein the electrolytic degreasing is performed for 1 to 15 seconds using an alkaline solution having a current density of 3 to 12 (C/ dm2 ), a concentration of 1 to 10%, and a liquid temperature of 30 to 120°C, and the finish annealing is performed at a dew point of -70 to -10°C.
  • the method for producing a non-oriented electrical steel sheet is characterized in that the steel slab further contains one or more components selected from Groups A to C in addition to the above-mentioned chemical composition.
  • Group A One or two selected from Sn: 0.005-0.20 mass%, Sb: 0.005-0.20 mass%
  • Group B One or more selected from Cu, Ni and Cr: 0.03-1.0 mass% in total
  • Group C one or more selected from Ca, Mg and REM: 0.0005 to 0.020 mass% in total
  • the method for producing a non-oriented electrical steel sheet further contains, in addition to the above-mentioned chemical composition, one or more components selected from the following groups D to G: In mass percent, Group D: one or more selected from Ge and Ga: 0.0005 to 0.01% in total E group: Zn: 0.001-0.05%
  • F group one or more selected from Mo, As and W: 0.001 to 0.05% in total
  • Group G one or more selected from
  • the present invention makes it possible to manufacture non-oriented electrical steel sheets with low iron loss in the high magnetic flux density range, making it possible to provide materials suitable for manufacturing motors that realize the miniaturization and high efficiency of electrical equipment.
  • 1 is a graph showing the relationship between Co content and iron loss.
  • 1 is a graph showing the relationship between the amount of surface layer nitriding (NasAlN)/Nc and iron loss.
  • 1 is a graph showing the relationship between electric charge density and iron loss.
  • 1 is a graph showing the relationship between the charge density and the surface layer nitride amount (NasAlN)/Nc.
  • 1 is a graph showing the relationship between alkali treatment concentration and iron loss.
  • 1 is a graph showing the relationship between the alkali treatment concentration and the surface layer nitride amount (NasAlN)/Nc.
  • 1 is a graph showing the relationship between alkali treatment temperature and iron loss.
  • 1 is a graph showing the relationship between the alkali treatment temperature and the surface layer nitride amount (NasAlN)/Nc.
  • 1 is a graph showing the relationship between alkali treatment time and iron loss.
  • 1 is a graph showing the relationship between the alkali treatment time and the surface layer nitride amount (NasAlN)/Nc.
  • Example 1 A steel containing 0.0025 mass% C, 2.9 mass% Si, 0.3 mass% Mn, 0.01 mass% P, 0.0019 mass% S, 0.6 mass% Al, 0.0023 mass% N, 0.0015 mass% Ti, 0.0009 mass% Nb, and 0.0020 mass% O, with Co varying in a range of 0.0001 to 0.02 mass%, and the balance being Fe and unavoidable impurities, was melted in a vacuum furnace and cast into a steel ingot. Next, the sheet was hot-rolled to a thickness of 2.0 mm, and then annealed at 950°C for 30 seconds.
  • the sheet was cold-rolled to a final thickness of 0.25 mm.
  • Test pieces measuring 30 mm wide x 180 mm long were cut out from the rolling direction (L direction) and width direction (C direction) of the thus obtained finish annealed sheet, and the iron loss W 17/50 in the high magnetic flux density region in the (L + C) direction was measured by the Epstein test.
  • the concentration (mass%) of nitrogen N present as AlN in the layer from the steel sheet surface to 1/20 of the sheet thickness and the concentration (mass%) of nitrogen N in the center of the steel sheet were analyzed by electrolytic extraction for this finish annealed sheet.
  • the ratio of the amount of nitrogen forming AlN in the layer (surface layer) from the steel sheet surface to 1/20 of the sheet thickness and the amount of nitrogen in the center of the steel sheet thickness is strongly correlated with the iron loss in the high magnetic flux density region.
  • Figure 2 shows the relationship between the ratio of the amount of nitrogen (amount of nitride in the surface layer/amount of nitrogen in the center of the sheet thickness) and the iron loss W 17/50 . It was found that the iron loss is greatly reduced when this ratio is 3.0 or less, and that the Co content of all steel sheets with this ratio of the amount of nitride being 3.0 or less is within the range of 0.001 to 0.01 mass%.
  • the steel sheet was manufactured as follows.
  • the sheet was hot-rolled to a thickness of 2.2 mm, and then annealed at 980°C for 30 seconds. After pickling, the sheet was cold-rolled to a final thickness of 0.35 mm.
  • the cold-rolled sheet was then electrolytically treated by changing the electrical charge density from 1 to 15 (C/dm 2 ) and immersing it in 3% sodium hydroxide at a liquid temperature of 90°C for 8 seconds.
  • a steel sheet was manufactured as follows. A steel containing C: 0.0028 mass%, Si: 3.2 mass%, Mn: 0.6 mass%, P: 0.01 mass%, S: 0.0019 mass%, Al: 0.8 mass%, N: 0.0022 mass%, Ti: 0.0011 mass%, Nb: 0.0007 mass%, O: 0.0020 mass%, Co: 0.0027 mass%, and the balance being Fe and inevitable impurities, was melted in a vacuum furnace and cast into a steel ingot. Next, the sheet was hot-rolled to a thickness of 2.2 mm, and then annealed at 980°C for 30 seconds.
  • the sheet was cold-rolled to a final thickness of 0.35 mm.
  • the cold-rolled sheet was then immersed in potassium hydroxide with a charge density of 4 (C/ dm2 ) and a liquid temperature of 90°C for 6 seconds, which was changed from 0.5 to 20%, for electrolysis.
  • the steel sheet was manufactured as follows.
  • the sheet was hot-rolled to a thickness of 2.2 mm, and then annealed at 980°C for 30 seconds.
  • the sheet was cold-rolled to a final thickness of 0.35 mm.
  • the cold-rolled sheet was then immersed in 3% calcium hydroxide for 4 seconds with a charge density of 4 (C/ dm2 ) and a liquid temperature of 20 to 150°C, and electrolytically treated.
  • the steel sheet was manufactured as follows. A steel containing C: 0.0028 mass%, Si: 3.2 mass%, Mn: 0.6 mass%, P: 0.01 mass%, S: 0.0019 mass%, Al: 0.8 mass%, N: 0.0022 mass%, Ti: 0.0011 mass%, Nb: 0.0007 mass%, O: 0.0020 mass%, Co: 0.0027 mass%, and the balance being Fe and inevitable impurities, was melted in a vacuum furnace and cast into a steel ingot. Next, the sheet was hot-rolled to a thickness of 2.2 mm, and then annealed at 980°C for 30 seconds.
  • the sheet was cold-rolled to a final thickness of 0.35 mm.
  • the cold-rolled sheet was then immersed in 3% sodium hydroxide with a charge density of 3 (C/ dm2 ) and a liquid temperature of 35°C for 5 to 30 seconds, and electrolytically treated.
  • Test pieces with a width of 30 mm and a length of 180 mm were cut out from the rolling direction (L direction) and the width direction (C direction) of the thus obtained finish annealed sheet, and the iron loss W 17/50 in the high magnetic flux density region in the (L + C) direction was measured by the Epstein test. Furthermore, the nitrogen content (N as AlN) of the steel sheet surface layer and the nitrogen content in the steel sheet thickness center were analyzed using the extraction residue.
  • the oxide layer of the steel sheet surface layer formed during finish annealing becomes thick, and nitriding during finish annealing is promoted through the oxide film.
  • Non-oriented electrical steel sheet The non-oriented electrical steel sheet according to this embodiment will be described. First, the reasons for limiting the composition of the non-oriented electrical steel sheet will be described. Note that “%” for components means “mass %” unless otherwise specified.
  • C 0.0050% or less
  • C is a harmful element that causes magnetic aging, forms carbides and precipitates, and deteriorates iron loss characteristics. Therefore, the C content is limited to 0.0050% or less. Preferably, the C content is 0.0040% or less. There is no particular lower limit for the C content, but from the viewpoint of suppressing the decarburization cost in the refining process, it is preferably about 0.0001%.
  • Si 2.0 to 6.5%
  • Si has the effect of increasing the resistivity of steel and reducing iron loss.
  • Si has the effect of increasing the strength of steel by solid solution strengthening, so the Si content is set to 2.0% or more.
  • the Si content is set to 6.5%.
  • the Si content is preferably 2.5 to 6.0%.
  • Mn 0.05 to 2.00% Mn, like Si, is a useful element for increasing the resistivity and strength of steel. It is also an element that forms sulfides to improve hot brittleness, so the Mn content is set to 0.05% or more. On the other hand, if the Mn content exceeds 2.00%, it causes slab cracking and deteriorates the operability in steelmaking, so the upper limit is set to 2.00%. Preferably, the Mn content is in the range of 0.10 to 1.50%.
  • P 0.10% or less
  • P is an element that has a large effect of increasing resistivity and reducing eddy current loss, so it can be added appropriately.
  • the upper limit of the P content is set to 0.10%.
  • the P content is 0.05% or less.
  • the P content is preferably 0.001% or more.
  • the upper limit of the S content is set to 0.0050%.
  • the S content is 0.0030% or less.
  • Al 0.3 to 2.0% Like Si, Al has the effect of increasing the resistivity of steel and reducing iron loss. However, if the Al content exceeds 2.0%, the steel becomes embrittled and difficult to roll, so the upper limit is set to 2.0%. On the other hand, if the Al content is less than 0.3%, fine nitrides are formed and precipitated, which rather deteriorates the iron loss characteristics, so the lower limit is set to 0.3%.
  • the Al content is preferably 0.4 to 1.5%.
  • N 0.0010 to 0.0050%
  • N is a harmful element that forms nitrides and deteriorates magnetic properties, so it is limited to 0.0050% or less.
  • limiting the N content to 0.0010% or less would significantly increase the cost of the refining process, so the lower limit is set to 0.0010%.
  • the N content is preferably 0.0015 to 0.0040%.
  • Co 0.0010 to 0.010%
  • the Co content is set to 0.0010% or more.
  • the oxide film layer (nitridation suppression layer) containing Co is not formed by the electrolytic alkaline pretreatment, although the reason is unclear, so the Co content is limited to 0.010% or less.
  • the Co content is 0.002 to 0.007%.
  • Ti 0.0030% or less
  • Ti is a harmful element that forms and precipitates fine carbonitrides, increasing iron loss.
  • the upper limit is set to 0.0030%.
  • the Ti content is 0.0020% or less.
  • Nb 0.0030% or less
  • Nb is a harmful element that forms fine carbonitrides and precipitates, increasing iron loss.
  • the Nb content exceeds 0.0030%, the above-mentioned adverse effects become significant, so the upper limit is set to 0.0030%.
  • the Nb content is 0.0020% or less.
  • O 0.0050% or less Since O is a harmful element that forms oxides and deteriorates magnetic properties, the O content is limited to 0.0050% or less. Preferably, the O content is 0.0040% or less.
  • the remainder of the non-oriented electrical steel sheet according to this embodiment is Fe and unavoidable impurities.
  • Sn and Sb have the effect of improving the recrystallized texture and improving the magnetic flux density and iron loss.
  • the Sn and Sb contents must be 0.005% or more.
  • the Sn and Sb contents are preferably 0.005-0.20%.
  • Group B one or more selected from Cu, Ni and Cr: 0.03 to 1.0% in total Cu, Ni, and Cr have the effect of increasing resistivity and reducing iron loss.
  • the total content of one or more selected from Cu, Ni, and Cr is 0.03% or more. Addition of one or more selected from Cu, Ni, and Cr in a total content of 1.0% or more leads to an increase in cost. Therefore, the total content of one or more selected from Cu, Ni, and Cr is preferably 0.03 to 1.0%. More preferably, the total content of one or more selected from Cu, Ni, and Cr is 0.05 to 0.8%.
  • Group C one or more selected from Ca, Mg and REM: 0.0005 to 0.020% in total Ca, Mg and REM have the effect of forming stable sulfides and improving grain growth.
  • the total content of one or more of Ca, Mg and REM is set to 0.0005% or more.
  • the total content of one or more of Ca, Mg and REM is preferably set to 0.0005 to 0.020%.
  • composition of the non-oriented electrical steel sheet it is preferable to further contain at least one group of components selected from the following groups D to G.
  • Group D one or two selected from Ge and Ga: 0.0005 to 0.01% in total Ge and Ga are elements that have the effect of improving the texture.
  • the total content of Ge and Ga is preferably set to 0.0020% or more.
  • the total content of Ge and Ga is set to 0.01% or less, and preferably to 0.0050% or less.
  • Zn 0.001-0.05%
  • Zn is an element that has the effect of suppressing nitridation during finish annealing.
  • the Zn content is 0.001 mass% or more, preferably 0.002% or more.
  • the Zn content exceeds 0.05 mass%, Zn forms sulfides, which increases iron loss. Therefore, the Zn content is limited to 0.05 mass% or less.
  • the Zn content is preferably in the range of 0.002 to 0.01 mass%.
  • F group one or more selected from Mo, As and W: 0.001 to 0.05% in total Mo
  • As and W are elements that have the effect of improving high-temperature strength, and by adding one or more of Mo, As and W, surface defects (scuffs) in the non-oriented electrical steel sheet can be suppressed.
  • the steel plate of the present invention is a high alloy steel, and the surface is easily oxidized, so that the occurrence rate of scabs due to surface cracks is high. Therefore, by adding one or more of Mo, As and W, the above cracks can be suppressed.
  • the total content of Mo, As, and W is set to 0.001% or more, preferably 0.005% or more.
  • the total content is set to 0.05% or less, preferably 0.02% or less.
  • Group G one or more selected from B, Pb and V: 0.0001 to 0.01% in total B, Pb and V are elements that have the effect of segregating at grain boundaries and improving the toughness of a steel sheet.
  • the steel plate of the present invention is a high alloy steel, and may have low toughness. Therefore, the toughness can be improved by adding one or more of B, Pb, and V.
  • the total content of B, Pb, and V is set to 0.0001% or more, preferably 0.0005% or more.
  • the total content exceeds 0.01%, carbonitrides are formed, which leads to an increase in iron loss. Therefore, the total content is set to 0.01% or less, preferably 0.0050% or less.
  • Oxide layer containing Si, Al and Co on the surface of the steel sheet The oxide layer containing Si, Al and Co suppresses nitridation on the surface of the steel sheet and realizes low iron loss. Therefore, at least one of the steel sheets has an oxide layer containing Si, Al and Co on its surface.
  • the oxide may be amorphous, may be a crystalline phase, or may be a composite oxide of amorphous and crystalline.
  • the ratio of the crystalline phase to the total of the amorphous phase and the crystalline phase contained in the oxide layer is preferably 0% or more and 30% or less, more preferably 0% or more and 10% or less.
  • Al concentration in oxide layer is 10 at% or more Among the elements contained in the oxide layer, Al and Co have a nitridation suppression effect, and the Al concentration is preferably 10 at% or more. This is because a higher Al concentration results in a denser oxide film, which increases the nitridation suppression effect during finish annealing.
  • the amount of Co added is very small, and when it is contained in the oxide layer, it exhibits the effect of suppressing nitridation. The difference in effect due to the concentration of Co is very small, and therefore the amount of Co added is not particularly limited.
  • it is preferable to set the electrical charge density of the electrolytic alkaline treatment to 5 to 10 (C/dm 2 ).
  • the thickness of the oxide layer is preferably 5 nm or more from the viewpoint of suppressing nitridation. On the other hand, if the oxide layer is excessively thick, the space factor of the steel sheet decreases, so the thickness of the oxide layer is preferably 50 nm or less.
  • the proportion of the crystalline phase and the thickness of the oxide layer can be measured by observation with a transmission electron microscope (TEM) and a scanning transmission electron microscope (STEM) and by energy dispersive X-ray spectroscopy (EDS) analysis. Specifically, a STEM-EDS element distribution map is measured at 50,000 times or more with a beam system of 1 nm or less, and then a TEM image is obtained at 300,000 times or more. From the obtained STEM-EDS element distribution map and TEM image, the regions where Al and O exist and where lattice fringes can be confirmed are regarded as crystalline phases, and the other regions where Al and O exist are regarded as amorphous phases.
  • TEM transmission electron microscope
  • STEM scanning transmission electron microscope
  • EDS energy dispersive X-ray spectroscopy
  • the thickness of the oxide layer can be measured by measuring the thickness of the Al region in the STEM-EDS elemental analysis map. Specifically, an EDS line profile is acquired at intervals of 0.5 nm, and from the obtained element distributions of Al, Si, Co, and O, the region where the weight fraction of O is 10% or more and the weight fractions of Al, Si, and Co are 3% or more is treated as the oxide layer.
  • the oxide layer may contain Fe, and the Fe concentration in the oxide layer is not particularly limited to an upper limit, but is preferably less than 100% as a ratio to Al or Si, or the sum of both. Measurements can be performed using STEM-EDS (100,000 times) or the like.
  • the amount of nitrogen (NasAlN) in the steel sheet surface layer present as AlN in the layer from the surface of the steel sheet to 1/20 of the sheet thickness is 0.01 mass% or less. If fine AlN precipitates are present in the steel sheet surface layer, iron loss in the high magnetic flux density region increases and magnetic properties deteriorate. Therefore, it is necessary to suppress the formation of AlN, and the amount of nitrogen present as AlN is expressed as an index of AlN, and the amount of nitrogen (NasAlN) in the steel sheet surface layer present as AlN is 0.01 mass% or less.
  • the nitrogen content Nc at the center of the steel plate thickness and the nitrogen content (NasAlN) in the surface layer of the steel plate satisfy the formula (1): (NasAlN)/Nc ⁇ 3.0 (1)
  • the ratio of the amount of nitrogen forming AlN in the layer from the steel sheet surface to 1/20 of the sheet thickness (surface layer) to the amount of nitrogen in the center of the steel sheet thickness has a strong correlation with iron loss in the high magnetic flux density region. Since iron loss decreases significantly when the nitrogen amount ratio is 3.0 or less, the nitrogen amount ratio was set to 3.0 or less.
  • Iron loss of steel sheet is 3.2 W/kg or less. If the iron loss exceeds 3.2 W/kg, the motor may generate heat or the efficiency of the motor may decrease when the motor is driven in the high torque range. Therefore, the iron loss of the steel sheet is set to 3.2 W/kg or less.
  • the method includes a hot rolling step of hot rolling a steel slab having the above-mentioned composition to obtain a hot-rolled sheet, a cold rolling step of annealing the hot-rolled sheet or performing one cold rolling or two or more cold rolling steps with intermediate annealing sandwiched therebetween to obtain a cold-rolled sheet without annealing, an electrolytic degreasing step of electrolytically degreasing the cold-rolled sheet, and a finish annealing step of finish annealing the electrolytically degreased cold-rolled sheet, the electrolytic degreasing being performed for 1 to 15 seconds using an alkaline solution with a charge density of 3 to 12 (C/dm 2 ), a concentration of 1 to 10%, and a liquid temperature of 30 to 120° C., and a dew point of ⁇ 70 to ⁇ 10° C. during the finish anne
  • the steel slab used in the manufacture of the non-oriented electrical steel sheet according to this embodiment can be produced by melting steel having the above-mentioned component composition suitable for the present invention through a commonly known refining process using a converter, an electric furnace, a vacuum degassing device, etc., and then by a conventional continuous casting method or an ingot making-blooming rolling method.
  • a thin cast piece having a thickness of 100 mm or less may also be produced by a direct casting method.
  • the steel slab is usually hot-rolled by a known method to obtain a hot-rolled sheet.
  • the steel slab is usually reheated to a predetermined temperature in a heating furnace before being subjected to hot rolling, but it may be subjected to hot rolling immediately after casting without being reheated. In the case of a thin cast piece, it may be hot-rolled or may be directly subjected to the subsequent steps without hot rolling.
  • the hot-rolled sheet may be annealed, or may be directly proceeded to the subsequent process without annealing.
  • the hot-rolled sheet annealing following hot rolling is preferably performed at a soaking temperature in the range of 800 to 1100 ° C. If the soaking temperature is less than 800 ° C, the effect of hot-rolled sheet annealing is small, and sufficient improvement of magnetic properties cannot be obtained. On the other hand, if the soaking temperature exceeds 1100 ° C, the crystal grains become coarse, which promotes brittle fracture (sheet breakage) during cold rolling or is disadvantageous in terms of manufacturing costs.
  • the soaking time is preferably 3 min or less from the viewpoint of ensuring productivity. More preferably, the soaking temperature is 850 to 1000 ° C, and the soaking time is 1 min or less.
  • Cold rolling is a process in which the hot-rolled annealed sheet that has been pickled is cold-rolled to the sheet thickness of the product sheet (final sheet thickness).
  • the steel sheet after the hot-rolled sheet annealing is then cold-rolled once or twice or more times with intermediate annealing between them to obtain a cold-rolled sheet having a final thickness.
  • the final thickness (product thickness) of the cold-rolled sheet is not particularly limited, but is preferably 0.50 mm or less from the viewpoint of obtaining the effect of reducing iron loss.
  • the cold-rolled sheet is electrolytically treated with an alkaline solution.
  • the conditions for the electrolytic alkaline treatment are a charge density of 3 to 12 (C/dm 2 ), an alkaline solution concentration of 1 to 10%, a treatment temperature of 30 to 120° C., and a time of 1 to 15 seconds in order to form a nitriding suppression layer (oxidation layer) during finish annealing.
  • the alkaline solution is selected from any one of sodium hydroxide, potassium hydroxide, calcium hydroxide, and sodium orthosilicate.
  • the charge density is preferably set to 5 to 10 (C/dm 2 ).
  • the finish annealing is performed at a low dew point. Specifically, the finish annealing is performed at a dew point of -70 to -10°C. This is because if the dew point exceeds -10°C, an oxide layer is formed inside the steel sheet, and the desired nitriding inhibition layer (oxide layer) is not formed on the surface layer of the steel sheet. In addition, since a low dew point of less than -70°C increases the industrial cost, the dew point of the finish annealing is set to -70 to -10°C.
  • the soaking temperature during finish annealing is preferably 900 to 1200°C, and more preferably 1000 to 1100°C.
  • the soaking time during finish annealing is preferably 1 to 120 seconds, and more preferably 5 to 60 seconds.
  • the steel sheet that has been subjected to the above-mentioned final annealing is then coated with an insulating coating as necessary to produce the finished sheet.
  • the insulating coating may be inorganic, organic, or a mixture of inorganic and organic, with no particular restrictions.
  • Test pieces were taken from the product sheets thus obtained, and test pieces 30 mm wide x 180 mm long were cut out from the rolling direction (L direction) and the width direction (C direction), and the iron loss W 17/50 in the (L+C) direction was measured by the Epstein test. Test pieces were also taken from the above samples, and subjected to electrolytic extraction analysis to analyze the nitrogen concentration N (mass%) from the steel sheet surface to a depth of 1/20 of the sheet thickness and the nitrogen concentration N (mass%) at the center of the steel sheet. The thickness of the surface oxide layer was also observed by TEM and STEM.
  • the present invention can reduce iron loss in the high magnetic flux density range without causing a decrease in magnetic flux density, making it suitable for use as a motor core material in hybrid electric vehicles, electric vehicles, generators, air conditioner compressors, vacuum cleaners, machine tools, etc.

Landscapes

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

Abstract

L'invention propose une feuille d'acier électromagnétique non orientée dans laquelle une diminution de la densité de flux magnétique et une diminution de la productivité sont évitées, et la perte de noyau dans une région de densité de flux magnétique élevée est faible. De plus, l'invention propose un procédé de production avantageux pour la feuille d'acier électromagnétique non orientée.　Cette feuille d'acier électromagnétique non orientée présente une composition de composant contenant C, Si, Mn, P, S, Al, N, Co, Ti, Nb et O, et comprend une couche d'oxyde contenant du Si, de l'Al et du Co dans au moins une surface de la feuille d'acier. La teneur en azote dans une couche de surface de feuille d'acier est d'au plus 0,01 % en masse. La teneur en azote Nc au niveau de la partie centrale dans la direction de l'épaisseur de la feuille d'acier et la teneur en azote (NasAlN) dans la couche de surface de feuille d'acier satisfont la formule (1). La perte de noyau de la feuille d'acier est d'au plus 3,2 W/kg lorsque la feuille d'acier est excitée à 50 Hz et 1,7 T. Ce procédé de production pour une feuille d'acier électromagnétique non orientée comprend : une étape de laminage à chaud d'une brame d'acier contenant la composition de composants susmentionnée, le laminage à froid de la brame d'acier après ou sans recuit, la soumission de la brame d'acier à un traitement de dégraissage électrolytique, et la soumission de la brame d'acier à un recuit de finition. Pour le traitement de dégraissage électrolytique, la densité de quantité d'électricité, la concentration, la température de liquide et la durée de traitement d'un liquide alcalin sont spécifiées. Le recuit de finition est effectué à un point de rosée bas.　(1) : (NasAlN)/Nc ≤ 3,0
PCT/JP2023/031961 2022-10-31 2023-08-31 Feuille d'acier électromagnétique non orientée et son procédé de production WO2024095595A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022174748 2022-10-31
JP2022-174748 2022-10-31

Publications (1)

Publication Number Publication Date
WO2024095595A1 true WO2024095595A1 (fr) 2024-05-10

Family

ID=90930174

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/031961 WO2024095595A1 (fr) 2022-10-31 2023-08-31 Feuille d'acier électromagnétique non orientée et son procédé de production

Country Status (1)

Country Link
WO (1) WO2024095595A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02240214A (ja) * 1989-03-15 1990-09-25 Nkk Corp 無方向性電磁鋼板の熱延板焼鈍方法
JP2006241563A (ja) * 2005-03-07 2006-09-14 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
WO2020136993A1 (fr) * 2018-12-27 2020-07-02 Ｊｆｅスチール株式会社 Tôle d'acier électrique non orientée et son procédé de production
CN114214561A (zh) * 2021-11-30 2022-03-22 马鞍山钢铁股份有限公司 一种超高效变频空调压缩机用无取向硅钢薄带及其制造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02240214A (ja) * 1989-03-15 1990-09-25 Nkk Corp 無方向性電磁鋼板の熱延板焼鈍方法
JP2006241563A (ja) * 2005-03-07 2006-09-14 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
WO2020136993A1 (fr) * 2018-12-27 2020-07-02 Ｊｆｅスチール株式会社 Tôle d'acier électrique non orientée et son procédé de production
CN114214561A (zh) * 2021-11-30 2022-03-22 马鞍山钢铁股份有限公司 一种超高效变频空调压缩机用无取向硅钢薄带及其制造方法

Similar Documents

Publication Publication Date Title
JP6738056B1 (ja) 無方向性電磁鋼板およびその製造方法
TWI820337B (zh) 無方向性電磁鋼板的製造方法與馬達鐵芯的製造方法、以及馬達鐵芯
CN110678568A (zh) 无方向性电磁钢板及其制造方法
WO2024095595A1 (fr) Feuille d'acier électromagnétique non orientée et son procédé de production
JP6950748B2 (ja) 無方向性電磁鋼板の製造方法
JP2003293101A (ja) 歪取焼鈍後の磁気特性および耐食性に優れた無方向性電磁鋼板
JP2022074677A (ja) 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
JP7392902B1 (ja) 無方向性電磁鋼板およびその製造方法
JP7392901B1 (ja) 無方向性電磁鋼板およびその製造方法
TWI834484B (zh) 無方向性電磁鋼板及其製造方法
TWI844248B (zh) 無方向性電磁鋼板及其製造方法
TW202419641A (zh) 無方向性電磁鋼板及其製造方法
JP7473862B1 (ja) 無方向性電磁鋼板の製造方法
WO2023282072A1 (fr) Tôle d'acier électrique non orientée et son procédé de fabrication
WO2024095666A1 (fr) Procédé de fabrication de tôle d'acier magnétique non orientée
KR20230143194A (ko) 무방향성 전자 강판 및 그 제조 방법
WO2023176866A1 (fr) Tôle d'acier électromagnétique non orientée, et procédé de fabrication de celle-ci
WO2024057940A1 (fr) Tôle d'acier électromagnétique non orientée à haute résistance et son procédé de fabrication

Legal Events

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

Ref document number: 23885361

Country of ref document: EP

Kind code of ref document: A1