Non-oriented electromagnetic steel sheet, rotor core, stator core, and motor

Abstract

Provided is a non-oriented electromagnetic steel sheet capable of achieving high strength and excellent magnetic flux density and further achieving excellent iron loss. The present disclosure provides a non-oriented electromagnetic steel sheet having a chemical composition described in the description, wherein: the sheet thickness t is 0.30 mm or less; F1 defined by formula (1) is 10.0 or greater; F2 defined by formula (2) is 8.5 or less; F3 defined by formula (3) is equal to or less than iron loss W5 / 1000 at a frequency of 1000 Hz and a magnetic flux density of 0.5 T; and F4 defined by formula (4) is equal to or greater than iron loss W10 / 400 at a frequency of 400 Hz and a magnetic flux density of 1.0 T when the non-oriented electromagnetic steel sheet is heat-treated at 800°C for 1 hour.　Formula (1): F1 = 4Si + 3Al + 2Mn Formula (2): F2 = 2Si + 3Al + Mn Formula (3): F3 = 45 - 12Si - 5Al - 2Mn + 1000 × t / (5 + 6Si + 5Al + 3Mn) Formula (4): F4 = 4 + 800 × t / (5 + 6Si + 5Al + 3Mn)

Description

Non-oriented electrical steel sheet, rotor core, stator core, and motor

[0001] The present disclosure relates to a non-oriented electrical steel sheet, a rotor core and a stator core manufactured using the non-oriented electrical steel sheet, and a motor including the rotor core and the stator core.

[0002] Non-oriented electrical steel sheets are widely used as the material for motor cores in motors. A motor core consists of a rotor core, which is the rotor part, and a stator core, which is the stator part. The rotor core and the stator core are required to have different characteristics.

[0003] Specifically, rotor cores are required to have not only low iron loss to improve motor efficiency, but also high strength for the following reasons. Motors for electric and hybrid vehicles are designed to increase motor output by increasing the motor rotation speed. Increasing motor output increases the centrifugal force acting on the rotor core, which is the rotor, while the motor is operating. Therefore, rotor cores are required to have both good iron loss and high strength.

[0004] On the other hand, the stator core does not require as high strength as the rotor core, and is required to have particularly good iron loss characteristics in order to improve motor efficiency.

[0005] As described above, the rotor core and the stator core have different required strength and iron loss levels. However, the rotor core and the stator core are manufactured using the same non-oriented electrical steel sheet. Specifically, the rotor core and the stator core are punched out from the same non-oriented electrical steel sheet.

[0006] Therefore, Japanese Patent Laid-Open Publication No. 2008-050686 (Patent Document 1) proposes a technique for obtaining a high-strength rotor core and a stator core with excellent iron loss performance from the same non-oriented electrical steel sheet.

[0007] In Patent Document 1, a thin non-oriented electrical steel sheet having a thickness of 0.15 to 0.35 mm is manufactured, which has a high-alloy chemical composition containing, by mass%, 0.0050% or less of C, 2.0% to 4.0% of Si, 0.05% to 2.0% of Mn, 3.0% or less of Al, 0.0030% or less of Ti, 0.0030% or less of S, 0.0030% or less of N, 0.0050% or less of V, 0.0050% or less of Nb, 0.0050% or less of Zr, and 0.0050% or less of As, with the balance being Fe and unavoidable impurities. A rotor and a stator are then punched out from the same non-oriented electrical steel sheet. Only the punched stator is heat-treated, while the punched rotor is not.

[0008] In Patent Document 1, high alloying of non-oriented electrical steel sheets achieves excellent iron loss and the high strength required for rotor cores. Then, heat treatment is performed on a stator core manufactured by punching high alloy and thin non-oriented electrical steel sheets, further reducing the iron loss of the stator core. With the above technology, an attempt is made to achieve both high strength for the rotor core and low iron loss for the stator using the same non-oriented electrical steel sheets.

[0009] Japanese Patent Application Laid-Open No. 2008-050686

[0010] As mentioned above, motors require high strength rotor cores and low iron loss stator cores. Motors also need to increase torque. Magnetic flux density is the driving force behind torque generation. Therefore, the non-oriented electrical steel sheet used as the material must also have excellent magnetic flux density.

[0011] In the above-mentioned Patent Document 1, a thin non-oriented electrical steel sheet is highly alloyed. In this case, it is certainly possible to reduce iron loss while ensuring strength. However, in the case of a high alloy and a thin non-oriented electrical steel sheet, sufficient magnetic flux density may not be obtained.

[0012] An object of the present invention is to provide a non-oriented electrical steel sheet, a rotor core, a stator core, and a motor that can achieve high strength, excellent magnetic flux density, and also excellent core loss.

[0013] The non-oriented electrical steel sheet according to the present disclosure has a chemical composition, in mass %, of Si: 2.0 to 4.0%, Mn: 0.1 to 1.5%, P: 0.15% or less, S: 0.0030% or less, Al: 0.1 to 2.0%, C: 0.0050% or less, N: 0.0050% or less, O: 0.0500% or less, Cr: 0 to 0.50%, Ti: 0 to 0.0030%, Mo: 0 to 0.100%, Ni: 0 to 0.50%, Cu: 0 to 0.50%, Sn: 0 to 0.100%, Sb: 0 to 0.100%, and Ca: 0 to 0.0000%. The alloy contains 50%, Mg: 0-0.0030%, rare earth elements: 0-0.0100%, B: 0-0.0030%, Zn: 0-0.0030%, Ge: 0-0.0030%, As: 0-0.0100%, Co: 0-0.0500%, V: 0-0.0030%, Se: 0-0.0030%, Zr: 0-0.0030%, Nb: 0-0.0030%, Pb: 0-0.0030%, and Ga: 0-0.0030%, with the balance being Fe and impurities. The alloy has a thickness t of 0.30 mm or less. F1 defined by formula (1) is 10.0 or more, and F2 defined by formula (2) is 8.5 or less. Furthermore, F3 defined in equation (3) is the iron loss W at a frequency of 1000 Hz and a magnetic flux density of 0.5 T. ５／１０００ F4 defined by the formula (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T when a non-oriented electrical steel sheet is heat-treated at 800 ° C. for 1 hour. １０／４００ That's all. F1 = 4Si + 3Al + 2Mn (1) F2 = 2Si + 3Al + Mn (2) F3 = 45 - 12Si - 5Al - 2Mn + 1000 x t / (5 + 6Si + 5Al + 3Mn) (3) F4 = 4 + 800 x t / (5 + 6Si + 5Al + 3Mn) (4) Here, the content of the corresponding element in mass% is substituted for each element symbol in formulas (1) to (4), and the plate thickness in mm is substituted for t.

[0014] A rotor core according to the present disclosure includes a plurality of laminated rotor core materials. The rotor core materials are plate-shaped. The rotor core materials have a chemical composition, in mass %, of 2.0 to 4.0% Si, 0.1 to 1.5% Mn, 0.15% or less P, 0.0030% or less S, 0.1 to 2.0% Al, 0.0050% or less C, 0.0050% or less N, 0.0500% or less O, 0 to 0.50% Cr, 0 to 0.0030% Ti, 0 to 0.100% Mo, 0 to 0.50% Ni, 0 to 0.50% Cu, 0 to 0.100% Sn, 0 to 0.100% Sb, and 0 to 0.0050% Ca. The steel sheet contains 0-0.0030% Mg, 0-0.0100% rare earth elements, 0-0.0030% B, 0-0.0030% Zn, 0-0.0030% Ge, 0-0.0030% As, 0-0.0100% Co, 0-0.0500% V, 0-0.0030% Se, 0-0.0030% Zr, 0-0.0030% Nb, 0-0.0030% Pb, and 0-0.0030% Ga, with the balance being Fe and impurities. The steel sheet has a thickness t of 0.30 mm or less. The F1 defined by formula (1) is 10.0 or more, and the F2 defined by formula (2) is 8.5 or less. Furthermore, F3 defined in equation (3) is the iron loss W at a frequency of 1000 Hz and a magnetic flux density of 0.5 T. ５／１０００ F4 defined by the formula (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T when the rotor core material is heat-treated at 800 ° C for 1 hour. １０／４００ That's all. F1 = 4Si + 3Al + 2Mn (1) F2 = 2Si + 3Al + Mn (2) F3 = 45 - 12Si - 5Al - 2Mn + 1000 x t / (5 + 6Si + 5Al + 3Mn) (3) F4 = 4 + 800 x t / (5 + 6Si + 5Al + 3Mn) (4) Here, the content of the corresponding element in mass% is substituted for each element symbol in formulas (1) to (4), and the plate thickness in mm is substituted for t.

[0015] A stator core according to the present disclosure includes a plurality of stacked stator core materials, each having an annular plate shape, and including a plurality of teeth arranged with gaps in the circumferential direction of the stator core material and extending in the radial direction of the stator core material. The chemical composition of the stator core material is, in mass%, Si: 2.0 to 4.0%, Mn: 0.1 to 1.5%, P: 0.15% or less, S: 0.0030% or less, Al: 0.1 to 2.0%, C: 0.0050% or less, N: 0.0050% or less, O: 0.0500% or less, Cr: 0 to 0.50%, Ti: 0 to 0.0030%, Mo: 0 to 0.100%, Ni: 0 to 0.50%, Cu: 0 to 0.50%, Sn: 0 to 0.100%, Sb: 0 to 0.100%, Ca: 0 to 0.0050%. , Mg: 0-0.0030%, rare earth elements: 0-0.0100%, B: 0-0.0030%, Zn: 0-0.0030%, Ge: 0-0.0030%, As: 0-0.0100%, Co: 0-0.0500%, V: 0-0.0030%, Se: 0-0.0030%, Zr: 0-0.0030%, Nb: 0-0.0030%, Pb: 0-0.0030%, and Ga: 0-0.0030%, with the balance being Fe and impurities. The sheet thickness t is 0.30 mm or less. F1 defined by formula (1) is 10.0 or more, and F2 defined by formula (2) is 8.5 or less. Furthermore, F4 defined in equation (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T. １０／４００ That is all. F1 = 4Si + 3Al + 2Mn (1) F2 = 2Si + 3Al + Mn (2) F4 = 4 + 800 × t / (5 + 6Si + 5Al + 3Mn) (4) Here, the content of the corresponding element in mass% is substituted for each element symbol in formulas (1), (2) and (4), and the plate thickness in mm is substituted for t.

[0016] A motor according to the present disclosure includes the above-described rotor core and the above-described stator core.

[0017] The non-oriented electrical steel sheet of the present disclosure provides high strength and excellent magnetic flux density, as well as excellent core loss. The rotor core of the present disclosure provides high strength and excellent magnetic flux density. The stator core of the present disclosure provides excellent magnetic flux density and excellent core loss.

[0018] FIG. 1A is a plan view showing an example of a rotor core of this embodiment. FIG. 1B is a plan view showing an example of a rotor core of this embodiment that is different from FIG. 1A. FIG. 1C is a plan view showing an example of a rotor core of this embodiment that is different from FIG. 1A and FIG. 1B. FIG. 2A is a cross-sectional view of the crimped portion taken along line IIA-IIA in FIG. 1A. FIG. 2B is a cross-sectional view of the crimped portion taken along line IIB-IIB in FIG. 1A. FIG. 3 is a plan view of a stator core of this embodiment.

[0019] The present inventors have investigated non-oriented electrical steel sheets that can achieve high strength, excellent magnetic flux density, and also excellent core loss. As described above, in order to achieve excellent magnetic flux density, it is preferable to avoid increasing the content of alloying elements. Therefore, the present inventors first investigated, from the viewpoint of chemical composition, non-oriented electrical steel sheets that can achieve high strength, excellent magnetic flux density, and excellent core loss after heat treatment. As a result, the chemical composition was found to be, in mass %, Si: 2.0 to 4.0%, Mn: 0.1 to 1.5%, P: 0.15% or less, S: 0.0030% or less, Al: 0.1 to 2.0%, C: 0.0050% or less, N: 0.0050% or less, O: 0.0500% or less, Cr: 0 to 0.50%, Ti: 0 to 0.0030%, Mo: 0 to 0.100%, Ni: 0 to 0.50%, Cu: 0 to 0.50%, Sn: 0 to 0.100%, Sb: 0 to 0.100%, Ca: 0 to 0.0050%, Mg: 0 to 0.0030%, and rare earth elements: 0%. The present inventors considered that a non-oriented electrical steel sheet containing Cr: 0-0.0100%, B: 0-0.0030%, Zn: 0-0.0030%, Ge: 0-0.0030%, As: 0-0.0100%, Co: 0-0.0500%, V: 0-0.0030%, Se: 0-0.0030%, Zr: 0-0.0030%, Nb: 0-0.0030%, Pb: 0-0.0030%, and Ga: 0-0.0030%, with the balance being Fe and impurities, could potentially provide high strength, excellent magnetic flux density, and excellent iron loss after heat treatment.

[0020] The present inventors further investigated means for obtaining high strength, excellent magnetic flux density, and excellent core loss in a non-oriented electrical steel sheet that satisfies the above-mentioned chemical composition.

[0021] In the above-mentioned chemical composition, Si, Al, and Mn increase the resistivity of the steel sheet and reduce iron loss. On the other hand, Si, Al, and Mn decrease the magnetic flux density. Therefore, the inventors further investigated the relationship between the Si content, Al content, and Mn content and the iron loss and magnetic flux density of steel sheets satisfying the above-mentioned chemical composition. As a result, the inventors found that in non-oriented electrical steel sheets satisfying the above-mentioned chemical composition, if F1 defined by formula (1) is 10.0 or more and F2 defined by formula (2) is 8.5 or less, excellent iron loss and excellent magnetic flux density can be achieved simultaneously. F1 = 4Si + 3Al + 2Mn (1) F2 = 2Si + 3Al + Mn (2) Here, the content of the corresponding element in mass % is substituted for each element symbol in formulas (1) and (2).

[0022] The inventors further investigated means for improving not only the strength but also the iron loss and magnetic flux density of a non-oriented electrical steel sheet that satisfies the above-mentioned chemical composition and has an F1 of 10.0 or more and an F2 of 8.5 or less. With the above-mentioned chemical composition, high strength due to alloying elements is not expected. Therefore, as a means for increasing strength other than high alloying, they focused on the amount of strain introduced into the steel sheet and the strain distribution within the steel sheet. If the amount of strain and strain distribution introduced into the steel sheet are appropriate, the strength of the steel sheet can be increased without relying on alloying elements. On the other hand, the strain introduced into the steel sheet deteriorates the iron loss. However, if the strain can be removed by heat treatment and the grain boundary area in the steel sheet can be reduced using the strain as a driving force, the iron loss can be further reduced.

[0023] It is extremely difficult to quantitatively express the strain amount and strain distribution in a steel sheet. Therefore, the inventors have investigated an index that correlates with the strain amount and strain distribution. As a result, it was found that F3 defined by the formula (3) is related to the iron loss W at a frequency of 1000 Hz and a magnetic flux density of 0.5 T. ５／１０００ F4 defined by the formula (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T when the non-oriented electrical steel sheet is annealed for stress relief. １０／４００It was found that if the above ratios are used, high strength and excellent magnetic flux density can be obtained, and further, excellent core loss can be obtained after heat treatment. F3 = 45 - 12Si - 5Al - 2Mn + 1000 × t / (5 + 6Si + 5Al + 3Mn) (3) F4 = 4 + 800 × t / (5 + 6Si + 5Al + 3Mn) (4) Here, the content of the corresponding element in mass% is substituted for each element symbol in formulas (3) and (4), and the plate thickness in mm is substituted for t.

[0024] The non-oriented electrical steel sheet, rotor core, stator core, and motor of this embodiment, which have been completed based on the above findings, have the following configurations.

[0025] The non-oriented electrical steel sheet of the first embodiment has a chemical composition, in mass %, of Si: 2.0 to 4.0%, Mn: 0.1 to 1.5%, P: 0.15% or less, S: 0.0030% or less, Al: 0.1 to 2.0%, C: 0.0050% or less, N: 0.0050% or less, O: 0.0500% or less, Cr: 0 to 0.50%, Ti: 0 to 0.0030%, Mo: 0 to 0.100%, Ni: 0 to 0.50%, Cu: 0 to 0.50%, Sn: 0 to 0.100%, Sb: 0 to 0.100%, and Ca: 0 to 0. 0.0050%, Mg: 0-0.0030%, rare earth elements: 0-0.0100%, B: 0-0.0030%, Zn: 0-0.0030%, Ge: 0-0.0030%, As: 0-0.0100%, Co: 0-0.0500%, V: 0-0.0030%, Se: 0-0.0030%, Zr: 0-0.0030%, Nb: 0-0.0030%, Pb: 0-0.0030%, Ga: 0-0.0030%, and the balance being Fe and impurities, and the plate thickness t is 0.30 mm or less. F1 defined by formula (1) is 10.0 or more, and F2 defined by formula (2) is 8.5 or less. Furthermore, F3 defined in equation (3) is the iron loss W at a frequency of 1000 Hz and a magnetic flux density of 0.5 T. ５／１０００ F4 defined by the formula (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T when a non-oriented electrical steel sheet is heat-treated at 800 ° C. for 1 hour. １０／４００That's all. F1 = 4Si + 3Al + 2Mn (1) F2 = 2Si + 3Al + Mn (2) F3 = 45 - 12Si - 5Al - 2Mn + 1000 x t / (5 + 6Si + 5Al + 3Mn) (3) F4 = 4 + 800 x t / (5 + 6Si + 5Al + 3Mn) (4) Here, the content of the corresponding element in mass% is substituted for each element symbol in formulas (1) to (4), and the plate thickness in mm is substituted for t.

[0026] The non-oriented electrical steel sheet of the second embodiment is the non-oriented electrical steel sheet of the first embodiment, and has a chemical composition of Cr: 0.01 to 0.50%, Ti: 0.0001 to 0.0030%, Mo: 0.001 to 0.100%, Ni: 0.01 to 0.50%, Cu: 0.01 to 0.50%, Sn: 0.001 to 0.100%, Sb: 0.001 to 0.100%, Ca: 0.0001 to 0.0050%, Mg: 0.0001 to 0.0030%, rare earth elements: 0.0001 to 0.0100%, B: 0.000 0.0001 to 0.0030%, Zn: 0.0001 to 0.0030%, Ge: 0.0001 to 0.0030%, As: 0.0001 to 0.0100%, Co: 0.0001 to 0.0500%, V: 0.0001 to 0.0030%, Se: 0.0001 to 0.0030%, Zr: 0.0001 to 0.0030%, Nb: 0.0001 to 0.0030%, Pb: 0.0001 to 0.0030%, and Ga: 0.0001 to 0.0030%.

[0027] A non-oriented electrical steel sheet of a third embodiment is the non-oriented electrical steel sheet of the first or second embodiment, and has a yield stress of 450 MPa or more and a fracture elongation of 20% or more.

[0028] The non-oriented electrical steel sheet of the fourth embodiment is a non-oriented electrical steel sheet of any one of the first to third embodiments, and has a magnetic flux density B in the direction of each angle at a pitch of 22.5° when the rolling direction is set as the reference 0°. ５０ A, B ５０ (0°), B ５０ (22.5°), B ５０ (45°), B ５０ (67.5°) and B ５０ (90°), the average magnetic flux density B defined by equation (5)５０ａｖｅ is 1.65T or more. ５０ａｖｅ = (B ５０ (0°) + 2 x B ５０ (22.5°) + 2 x B ５０ (45°) + 2 x B ５０ (67.5°) + B ５０ (90°)) / 8 (5)

[0029] The non-oriented electrical steel sheet of the fifth embodiment is the non-oriented electrical steel sheet of any one of the first to fourth embodiments, and when the non-oriented electrical steel sheet is heat-treated at 800°C for 1 hour, the iron loss W １０／４００ Furthermore, the magnetic flux density B in the direction of each angle at a pitch of 22.5° when the rolling direction is set as the reference 0° is １ A, B １ (0°), B １ (22.5°), B １ (45°), B １ (67.5°) and B １ (90°), the average magnetic flux density B defined by equation (6) １ａｖｅ The magnetic flux density B ５００ The magnetic flux density B in each angle direction at 22.5° pitch when the direction of the maximum value is set as the reference 0° ５００ A, B ５００ (0°), B ５００ (22.5°), B ５００ (45°), B ５００ (67.5°) and B ５００ (90°), the average magnetic flux density B defined by equation (7) ５００ａｖｅ is 1.98T or more. B １ａｖｅ = (B １ (0°) + 2 x B １ (22.5°) + 2 x B １ (45°) + 2 x B １ (67.5°) + B １ (90°)) / 8 (6) B ５００ａｖｅ = (B ５００ (0°) + 2 x B ５００ (22.5°) + 2 x B ５００ (45°) + 2 x B ５００ (67.5°) + B ５００ (90°)) / 8 (7)

[0030] A non-oriented electrical steel sheet of a sixth embodiment is the non-oriented electrical steel sheet of any one of the first to fifth embodiments, and has a thermal conductivity of 20 W / mK or more at 20°C and a thermal conductivity of 23 W / mK or more at 150°C.

[0031] A rotor core according to a first embodiment includes a plurality of laminated rotor core materials. The rotor core materials are plate-shaped. The rotor core materials have a chemical composition, in mass %, of 2.0 to 4.0% Si, 0.1 to 1.5% Mn, 0.15% or less P, 0.0030% or less S, 0.1 to 2.0% Al, 0.0050% or less C, 0.0050% or less N, 0.0500% or less O, 0 to 0.50% Cr, 0 to 0.0030% Ti, 0 to 0.100% Mo, 0 to 0.50% Ni, 0 to 0.50% Cu, 0 to 0.100% Sn, 0 to 0.100% Sb, and 0 to 0.005% Ca. 0%, Mg: 0-0.0030%, rare earth elements: 0-0.0100%, B: 0-0.0030%, Zn: 0-0.0030%, Ge: 0-0.0030%, As: 0-0.0100%, Co: 0-0.0500%, V: 0-0.0030%, Se: 0-0.0030%, Zr: 0-0.0030%, Nb: 0-0.0030%, Pb: 0-0.0030%, Ga: 0-0.0030%, and the balance being Fe and impurities, and the plate thickness t is 0.30 mm or less. F1 defined by formula (1) is 10.0 or more, and F2 defined by formula (2) is 8.5 or less. Furthermore, F3 defined in equation (3) is the iron loss W at a frequency of 1000 Hz and a magnetic flux density of 0.5 T. ５／１０００ F4 defined by the formula (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T when the rotor core material is heat-treated at 800 ° C for 1 hour. １０／４００ That's all. F1 = 4Si + 3Al + 2Mn (1) F2 = 2Si + 3Al + Mn (2) F3 = 45 - 12Si - 5Al - 2Mn + 1000 × t / (5 + 6Si + 5Al + 3Mn) (3) F4 = 4 + 800 × t / (5 + 6Si + 5Al + 3Mn) (4) Here, the content of the corresponding element in mass% is substituted for each element symbol in formulas (1) to (4), and the plate thickness in mm is substituted for t.

[0032] A rotor core according to a second embodiment is the rotor core according to the first embodiment, wherein the rotor core material further includes a crimped portion and a flat portion that is a flat region. The crimped portion includes an inclined portion that is inclined relative to the flat portion. The thickness of the inclined portion is 85% or less of the thickness of the flat portion.

[0033] The rotor core of the third embodiment is the rotor core of the second embodiment, and in a cross section including the central axis of the rotor core material, the Vickers hardness H １４ is 180 HV or more, and the Vickers hardness H １２１ Is H １４ It is +40HV or more.

[0034] A stator core according to a first embodiment includes a plurality of stacked stator core materials, each having an annular plate shape, arranged with gaps between them in the circumferential direction of the stator core material and including a plurality of teeth extending in the radial direction of the stator core material. The chemical composition of the stator core material is, in mass%, Si: 2.0 to 4.0%, Mn: 0.1 to 1.5%, P: 0.15% or less, S: 0.0030% or less, Al: 0.1 to 2.0%, C: 0.0050% or less, N: 0.0050% or less, O: 0.0500% or less, Cr: 0 to 0.50%, Ti: 0 to 0.0030%, Mo: 0 to 0.100%, Ni: 0 to 0.50%, Cu: 0 to 0.50%, Sn: 0 to 0.100%, Sb: 0 to 0.100%, Ca: 0 to 0.0050%. , Mg: 0-0.0030%, rare earth elements: 0-0.0100%, B: 0-0.0030%, Zn: 0-0.0030%, Ge: 0-0.0030%, As: 0-0.0100%, Co: 0-0.0500%, V: 0-0.0030%, Se: 0-0.0030%, Zr: 0-0.0030%, Nb: 0-0.0030%, Pb: 0-0.0030%, and Ga: 0-0.0030%, with the balance being Fe and impurities. The sheet thickness t is 0.30 mm or less. F1 defined by formula (1) is 10.0 or more, and F2 defined by formula (2) is 8.5 or less. Furthermore, F4 defined in equation (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T. １０／４００That is all. F1 = 4Si + 3Al + 2Mn (1) F2 = 2Si + 3Al + Mn (2) F4 = 4 + 800 × t / (5 + 6Si + 5Al + 3Mn) (4) Here, the content of the corresponding element in mass% is substituted for each element symbol in formulas (1), (2) and (4), and the plate thickness in mm is substituted for t.

[0035] A stator core according to a second embodiment is the stator core according to the first embodiment, wherein the stator core material further includes a crimped portion and a flat portion that is a flat region. The crimped portion includes an inclined portion that is inclined relative to the flat portion. The thickness of the inclined portion is 85% or less of the thickness of the flat portion.

[0036] The stator core of the third embodiment is the stator core of the second embodiment, and in a cross section including the central axis of the stator core material, the Vickers hardness H ２４ is 175HV or more, and the Vickers hardness H ２２１ is the Vickers hardness H ２４ It is ±10HV or less.

[0037] The motor of the first aspect includes a rotor core of any one of the first to third aspects and a stator core of any one of the first to third aspects.

[0038] The non-oriented electrical steel sheet, rotor core, stator core, and motor of this embodiment will be described below. Note that "%" regarding the content of an element means mass % unless otherwise specified.

[0039] [Features of the Non-oriented Electrical Steel Sheet of the Present Embodiment] The non-oriented electrical steel sheet of the present embodiment satisfies the following features 1 to 5. (Feature 1) The chemical composition, in mass %, is: Si: 2.0 to 4.0%, Mn: 0.1 to 1.5%, P: 0.15% or less, S: 0.0030% or less, Al: 0.1 to 2.0%, C: 0.0050% or less, N: 0.0050% or less, O: 0.0500% or less, Cr: 0 to 0.50%, Ti: 0 to 0.0030%, Mo: 0 to 0.100%, Ni: 0 to 0.50%, Cu: 0 to 0.50%, Sn: 0 to 0.100%, Sb: 0 to 0.100%, and Ca: 0 to 0.0050%. %, Mg: 0-0.0030%, rare earth elements: 0-0.0100%, B: 0-0.0030%, Zn: 0-0.0030%, Ge: 0-0.0030%, As: 0-0.0100%, Co: 0-0.0500%, V: 0-0.0030%, Se: 0-0.0030%, Zr: 0-0.0030%, Nb: 0-0.0030%, Pb: 0-0.0030%, and Ga: 0-0.0030%, with the balance consisting of Fe and impurities. (Feature 2) The plate thickness t is 0.30 mm or less. (Feature 3) F1, defined by formula (1), is 10.0 or more. F1 = 4Si + 3Al + 2Mn (1) Here, the content of the corresponding element in mass % is substituted for each element symbol in formula (1). (Feature 4) F2 defined in formula (2) is 8.5 or less. F2 = 2Si + 3Al + Mn (2) Here, the content of the corresponding element in mass % is substituted for each element symbol in formula (2). (Feature 5) F3 defined in formula (3) is less than or equal to the iron loss W at a frequency of 1000 Hz and a magnetic flux density of 0.5 T. ５／１０００ F4 defined by the formula (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T when a non-oriented electrical steel sheet is heat-treated at 800 ° C for 1 hour. １０／４００ That's all. F3 = 45 - 12Si - 5Al - 2Mn + 1000 × t / (5 + 6Si + 5Al + 3Mn) (3) F4 = 4 + 800 × t / (5 + 6Si + 5Al + 3Mn) (4) Here, the content of the corresponding element in mass% is substituted for each element symbol in formulas (3) and (4), and the plate thickness in mm is substituted for t. Features 1 to 5 will be explained below.

[0040] [(Feature 1) Chemical Composition] The chemical composition of the non-oriented electrical steel sheet according to this embodiment contains the following elements. Note that "%" in the chemical composition of the non-oriented electrical steel sheet means mass % unless otherwise specified.

[0041] Si: 2.0 to 4.0% Silicon (Si) increases the resistivity of the steel sheet and reduces eddy current loss. As a result, iron loss of the steel sheet is reduced. Si also dissolves in the steel sheet to increase its strength. If the Si content is less than 2.0%, the above effects cannot be fully achieved even if the contents of other elements are within the ranges of this embodiment. On the other hand, if the Si content exceeds 4.0%, the punching workability of the non-oriented electrical steel sheet decreases even if the contents of other elements are within the ranges of this embodiment. Therefore, the Si content is 2.0 to 4.0%. The preferred lower limit of the Si content is 2.1%, more preferably 2.2%, even more preferably 2.3%, even more preferably 2.5%, and even more preferably 2.8%. The preferred upper limit of the Si content is 3.7%, even more preferably 3.6%, even more preferably 3.5%, and even more preferably 3.2%.

[0042] Mn: 0.1 to 1.5% Manganese (Mn) increases the resistivity of the steel sheet and reduces eddy current loss. As a result, iron loss of the steel sheet is reduced. If the Mn content is less than 0.1%, the above effect cannot be sufficiently obtained even if the contents of other elements are within the ranges of this embodiment. On the other hand, if the Mn content exceeds 1.5%, the magnetic flux density of the steel sheet decreases even if the contents of other elements are within the ranges of this embodiment. Therefore, the Mn content is 0.1 to 1.5%. A preferred lower limit of the Mn content is 0.2%, more preferably 0.3%, and even more preferably 0.4%. A preferred upper limit of the Mn content is 1.0%, more preferably 0.8%, even more preferably 0.7%, and even more preferably 0.6%.

[0043] P: 0.15% or less Phosphorus (P) is unavoidably contained. In other words, the P content is greater than 0%. P increases the strength of the steel sheet through solid solution strengthening. Even if even a small amount of P is contained, the above effect can be obtained to some extent. However, if the P content exceeds 0.15%, even if the contents of other elements are within the ranges of this embodiment, the steel sheet becomes embrittled, workability deteriorates, and cracks may occur in the steel sheet during cold rolling. Therefore, the P content is 0.15% or less. The preferred lower limit of the P content is 0.01%, more preferably 0.03%. The preferred upper limit of the P content is 0.12%, more preferably 0.10%, and even more preferably 0.08%.

[0044] S: 0.0030% or less Sulfur (S) is an unavoidable impurity. In other words, the S content is greater than 0%. If the S content exceeds 0.0030%, even if the contents of other elements are within the ranges of this embodiment, S will produce excessive sulfides such as MnS. These sulfides deteriorate the iron loss and magnetic flux density of the steel sheet. Therefore, the S content is 0.0030% or less. The S content is preferably as low as possible. However, excessive reduction of the S content increases manufacturing costs. Therefore, from the viewpoint of industrial productivity, the lower limit of the S content is preferably greater than 0.0001%, more preferably 0.0003%, even more preferably 0.0004%, and even more preferably 0.0005%. The upper limit of the S content is preferably 0.0020%, more preferably 0.0018%, even more preferably 0.0017%, even more preferably 0.0015%, even more preferably 0.0010%, and even more preferably 0.0008%.

[0045] Al: 0.1 to 2.0% Aluminum (Al) increases the resistivity of the steel sheet and reduces eddy current loss. As a result, iron loss of the steel sheet is reduced. If the Al content is less than 0.1%, the above effect cannot be sufficiently obtained even if the contents of other elements are within the ranges of this embodiment. On the other hand, if the Al content exceeds 2.0%, the magnetic flux density of the steel decreases even if the contents of other elements are within the ranges of this embodiment. Therefore, the Al content is 0.1 to 2.0%. A preferred lower limit of the Al content is 0.2%, more preferably 0.3%, and even more preferably 0.4%. A preferred upper limit of the Al content is 1.8%, more preferably 1.6%, and even more preferably 1.4%. In this specification, the Al content in the chemical composition of a non-oriented electrical steel sheet refers to the content of acid-soluble Al (sol. Al).

[0046] C: 0.0050% or less Carbon (C) adheres to dislocations in the steel sheet to increase its strength. Even if even a small amount of C is contained, the above effect can be achieved to some extent. However, if the C content exceeds 0.0050%, even if the contents of other elements are within the ranges of this embodiment, excessive carbides are formed, degrading the iron loss and magnetic flux density of the steel sheet. Therefore, the C content is 0.0050% or less. The preferred lower limit of the C content is more than 0%, more preferably 0.0001%, more preferably more than 0.0001%, more preferably 0.0005%, even more preferably 0.0008%, and even more preferably 0.0010%. The preferred upper limit of the C content is 0.0040%, more preferably 0.0036%, even more preferably 0.0030%, even more preferably 0.0025%, and even more preferably 0.0020%.

[0047] N: 0.0050% or less Nitrogen (N) is an unavoidable impurity. That is, the N content is greater than 0%. If the N content exceeds 0.0050%, even if the contents of other elements are within the ranges of this embodiment, N forms excessive nitrides in the steel sheet, degrading the iron loss and magnetic flux density of the steel sheet. Therefore, the N content is 0.0050% or less. The N content is preferably as low as possible. However, excessive reduction of the N content increases manufacturing costs. Therefore, from the viewpoint of industrial productivity, the preferred lower limit of the N content is 0.0001%, more preferably 0.0005%, even more preferably 0.0010%, even more preferably 0.0013%, and even more preferably 0.0015%. The preferred upper limit of the N content is 0.0040%, even more preferably 0.0030%, and even more preferably 0.0025%.

[0048] O: 0.0500% or less Oxygen (O) is an unavoidable impurity. In other words, the O content is greater than 0%. If the O content exceeds 0.0500%, even if the contents of other elements are within the ranges of this embodiment, O will form excessive oxides in the steel sheet, degrading the iron loss and magnetic flux density of the steel sheet. Therefore, the O content is 0.0500% or less. The O content is preferably as low as possible. However, excessive reduction of the O content increases production costs. Therefore, from the viewpoint of industrial productivity, the preferred lower limit of the O content is 0.0001%, more preferably 0.0005%, even more preferably 0.0010%, and even more preferably 0.0015%. The preferred upper limit of the O content is 0.0200%, even more preferably 0.0100%, even more preferably 0.0050%, and even more preferably 0.0030%.

[0049] The balance of the chemical composition of the non-oriented electrical steel sheet of this embodiment is composed of Fe and impurities. Here, the impurities are unintentionally contained substances that are mixed in from raw materials such as ore and scrap, or from the manufacturing environment, during industrial production of the non-oriented electrical steel sheet. The content of these impurities is permissible within a range that does not adversely affect the non-oriented electrical steel sheet of this embodiment.

[0050] [Optional Elements] The chemical composition of the non-oriented electrical steel sheet of this embodiment further includes, in place of a portion of Fe, Cr: 0 to 0.50%, Ti: 0 to 0.0030%, Mo: 0 to 0.100%, Ni: 0 to 0.50%, Cu: 0 to 0.50%, Sn: 0 to 0.100%, Sb: 0 to 0.100%, Ca: 0 to 0.0050%, Mg: 0 to 0.0030%, rare earth elements: 0 to 0.0100%, B: 0 to 0. 0.0030%, Zn: 0-0.0030%, Ge: 0-0.0030%, As: 0-0.0100%, Co: 0-0.0500%, V: 0-0.0030%, Se: 0-0.0030%, Zr: 0-0.0030%, Nb: 0-0.0030%, Pb: 0-0.0030%, and Ga: 0-0.0030% may be contained. These optional elements will be described below.

[0051] [First Group: Cr] The chemical composition of the non-oriented electrical steel sheet of this embodiment may further contain Cr in place of a portion of Fe.

[0052] Cr: 0 to 0.50%. Chromium (Cr) is an optional element and does not necessarily need to be contained. That is, the Cr content may be 0%. When chromium is contained, that is, when the Cr content exceeds 0%, Cr, like Si, increases the resistivity of the steel sheet and reduces eddy current loss. As a result, the iron loss of the steel sheet is reduced. Even if even a small amount of Cr is contained, the above effects can be obtained to some extent. However, if the Cr content exceeds 0.50%, the magnetic flux density of the steel sheet decreases. Therefore, the Cr content is 0 to 0.50%. The preferred lower limit of the Cr content is 0.01%, more preferably 0.02%, and even more preferably 0.03%. The preferred upper limit of the Cr content is 0.40%, more preferably 0.35%, even more preferably 0.30%, and even more preferably 0.10%.

[0053] [Second Group: Ti, Mo, Ni, and Cu] The chemical composition of the non-oriented electrical steel sheet according to this embodiment may further contain one or more elements selected from the group consisting of Ti, Mo, Ni, and Cu, in place of a portion of Fe. These elements are optional elements, and all of them increase the strength of the steel sheet. Each element will be described below.

[0054] Ti: 0 to 0.0030% Titanium (Ti) is an optional element and may not be contained. In other words, the Ti content may be 0%. When Ti is contained, that is, when the Ti content exceeds 0%, Ti forms carbonitrides and increases the strength of the non-oriented electrical steel sheet through precipitation strengthening. Even if even a small amount of Ti is contained, the above effect can be achieved to some extent. However, if the Ti content exceeds 0.0030%, even if the contents of other elements are within the ranges of this embodiment, excessive carbonitrides will be formed, deteriorating the magnetic properties. Therefore, the Ti content is 0 to 0.0030%. The preferred lower limit of the Ti content is 0.0001%, more preferably 0.0005%, and even more preferably 0.0010%. The preferred upper limit of the Ti content is 0.0025%, more preferably 0.0020%, and even more preferably 0.0017%.

[0055] Mo: 0 to 0.100% Molybdenum (Mo) is an optional element and does not necessarily need to be contained. That is, the Mo content may be 0%. When Mo is contained, that is, when the Mo content exceeds 0%, Mo forms carbonitrides and increases the strength of the non-oriented electrical steel sheet through precipitation strengthening. Even if even a small amount of Mo is contained, the above effect can be achieved to some extent. However, if the Mo content exceeds 0.100%, even if the contents of other elements are within the ranges of this embodiment, excessive carbides will be formed, deteriorating the magnetic properties. Therefore, the Mo content is 0 to 0.100%. The preferred lower limit of the Mo content is 0.001%, more preferably 0.005%, even more preferably 0.010%, and even more preferably 0.015%. The preferred upper limit of the Mo content is 0.090%, even more preferably 0.080%, even more preferably 0.075%, and even more preferably 0.070%.

[0056] Ni: 0 to 0.50% Nickel (Ni) is an optional element and does not necessarily need to be contained. That is, the Ni content may be 0%. When contained, that is, when the Ni content exceeds 0%, Ni increases the strength of the steel sheet through solid solution strengthening. Even if even a small amount of Ni is contained, the above effect can be obtained to some extent. However, if the Ni content exceeds 0.50%, the steel sheet becomes embrittled and workability deteriorates, even if the contents of other elements are within the ranges of this embodiment. Therefore, the Ni content is 0 to 0.50%. The preferred lower limit of the Ni content is 0.01%, more preferably 0.02%, and even more preferably 0.03%. The preferred upper limit of the Ni content is 0.35%, more preferably 0.20%, and even more preferably 0.10%.

[0057] Cu: 0 to 0.50% Copper (Cu) is an optional element and does not necessarily need to be contained. In other words, the Cu content may be 0%. When contained, Cu increases the strength of the non-oriented electrical steel sheet. Even if even a small amount of Cu is contained, the above effect can be obtained to some extent. However, if the Cu content exceeds 0.50%, the steel sheet becomes embrittled and its workability decreases. Therefore, the Cu content is 0 to 0.50%. The preferred lower limit of the Cu content is 0.01%, more preferably 0.02%, and even more preferably 0.03%. The preferred upper limit of the Cu content is 0.30%, more preferably 0.20%, even more preferably 0.15%, and even more preferably 0.10%.

[0058] [Third Group: Sn, Sb, Ca, Mg, and Rare Earth Elements (REM)] The chemical composition of the non-oriented electrical steel sheet according to this embodiment may further contain, in place of a portion of Fe, one or more elements selected from the group consisting of Sn, Sb, Ca, Mg, and rare earth elements (REM). These elements are optional elements, and all of them improve the magnetic properties of the steel sheet. Each element will be described below.

[0059] Sn: 0 to 0.100% Tin (Sn) is an optional element and does not necessarily need to be contained. That is, the Sn content may be 0%. When Sn is contained, that is, when the Sn content exceeds 0%, Sn segregates on the surface of the steel sheet and suppresses oxidation and nitridation during finish annealing. This reduces the iron loss of the non-oriented electrical steel sheet. Sn also improves the texture of the steel sheet and increases the magnetic flux density. Even if even a small amount of Sn is contained, the above effects can be achieved to some extent. However, if the Sn content exceeds 0.100%, the steel sheet becomes embrittled and its workability deteriorates, even if the contents of other elements are within the ranges of this embodiment. Therefore, the Sn content is 0 to 0.100%. The preferred lower limit of the Sn content is 0.001%, more preferably 0.005%, and even more preferably 0.010%. The preferred upper limit of the Sn content is 0.080%, more preferably 0.070%, and even more preferably 0.060%.

[0060] Sb: 0 to 0.100% Antimony (Sb) is an optional element and may not be contained. That is, the Sb content may be 0%. When contained, that is, when the Sb content exceeds 0%, Sb segregates on the surface of the steel sheet and suppresses oxidation and nitridation during finish annealing. This reduces the iron loss of the non-oriented electrical steel sheet. Sb also improves the texture of the steel sheet and increases the magnetic flux density. Even if even a small amount of Sb is contained, the above effects can be achieved to some extent. However, if the Sb content exceeds 0.100%, the steel sheet becomes embrittled and its workability deteriorates, even if the contents of other elements are within the ranges of this embodiment. Therefore, the Sb content is 0 to 0.100%. The preferred lower limit of the Sb content is 0.001%, more preferably 0.003%, even more preferably 0.005%, and even more preferably 0.010%. The upper limit of the Sb content is preferably 0.080%, more preferably 0.070%, even more preferably 0.060%, even more preferably 0.040%, even more preferably 0.030%, and even more preferably 0.020%.

[0061] Ca: 0 to 0.0050% Calcium (Ca) is an optional element and may not be contained. That is, the Ca content may be 0%. When contained, that is, when the Ca content exceeds 0%, Ca combines with S during the casting of molten steel to form coarse precipitates, such as coarse sulfides and / or coarse oxysulfides. The coarse sulfides adsorb inhibitors, such as MnS, TiN, and AlN, with fine grain sizes of approximately 100 nm, that are formed in the steel sheet during manufacturing processes after the casting process. This suppresses the inhibition of grain growth by inhibitors during final annealing. Therefore, grain growth is promoted during final annealing. As a result, the magnetic properties of the non-oriented electrical steel sheet are improved. Even if even a small amount of Ca is contained, the above effects can be achieved to some extent. However, when the Ca content exceeds 0.0050%, excessive coarse precipitates are formed even when the contents of other elements are within the ranges of this embodiment. In this case, recrystallization and grain growth during the final annealing process are inhibited. Therefore, the Ca content is 0 to 0.0050%. The lower limit of the Ca content is preferably 0.0001%, more preferably 0.0005%, and even more preferably 0.0010%. The upper limit of the Ca content is preferably 0.0040%, more preferably 0.0035%, even more preferably 0.0030%, and even more preferably 0.0025%.

[0062] Mg: 0 to 0.0030% Magnesium (Mg) is an optional element and does not necessarily need to be contained. That is, the Mg content may be 0%. When contained, that is, when the Mg content exceeds 0%, Mg, like Ca, forms coarse precipitates and suppresses the inhibition of grain growth by inhibitors during final annealing. Therefore, grain growth is promoted during final annealing. As a result, the magnetic properties of the non-oriented electrical steel sheet are improved. Even if even a small amount of Mg is contained, the above effect can be achieved to some extent. However, if the Mg content exceeds 0.0030%, excessive coarse precipitates will form even if the contents of other elements are within the ranges of this embodiment. In this case, recrystallization and grain growth during the final annealing process will be inhibited. Therefore, the Mg content is 0 to 0.0030%. The preferred lower limit of the Mg content is 0.0001%, more preferably 0.0002%, and even more preferably 0.0003%. The upper limit of the Mg content is preferably 0.0020%, more preferably 0.0015%, and even more preferably 0.0010%.

[0063] Rare earth elements (REM): 0 to 0.0100% Rare earth elements (REM) are optional elements and may not be contained. That is, the REM content may be 0%. When contained, that is, when the REM content exceeds 0%, REM, like Ca, forms coarse precipitates and suppresses the inhibition of grain growth by inhibitors during final annealing. Therefore, grain growth is promoted during final annealing. As a result, the magnetic properties of the non-oriented electrical steel sheet are improved. Even if even a small amount of REM is contained, the above effect can be achieved to some extent. However, if the REM content exceeds 0.0100%, excessive coarse precipitates are formed even if the contents of other elements are within the ranges of this embodiment. In this case, recrystallization and grain growth during the final annealing process are inhibited. Therefore, the REM content is 0 to 0.0100%. The lower limit of the REM content is preferably 0.0001%, more preferably 0.0005%, and even more preferably 0.0010%. The upper limit of the REM content is preferably 0.0050%, more preferably 0.0045%, even more preferably 0.0040%, and even more preferably 0.0030%.

[0064] In this specification, REM refers to one or more elements selected from the group consisting of scandium (Sc) with atomic number 21, yttrium (Y) with atomic number 39, and lanthanoids lanthanum (La) with atomic number 57 to lutetium (Lu) with atomic number 71. In addition, in this specification, the REM content refers to the total content of these elements.

[0065] [Fourth Group: B] The chemical composition of the non-oriented electrical steel sheet of this embodiment may further contain B instead of a portion of Fe.

[0066] B: 0 to 0.0030% Boron (B) is an optional element and does not necessarily need to be contained. In other words, the B content may be 0%. If it is contained, that is, if the B content exceeds 0%, B forms nitrides that inhibit recrystallization during finish annealing. Therefore, the B content is 0 to 0.0030%. An excessive reduction in the B content increases production costs. Therefore, from the viewpoint of industrial productivity, the preferred lower limit of the B content is 0.0001%, more preferably 0.0002%, and even more preferably 0.0003%. The preferred upper limit of the B content is 0.0020%, more preferably 0.0015%, even more preferably 0.0010%, and even more preferably 0.0007%.

[0067] [Fifth Group: Zn, Ge, As, and Co] The chemical composition of the non-oriented electrical steel sheet of this embodiment may further contain one or more elements selected from the group consisting of Zn, Ge, As, and Co, in place of a portion of Fe. These elements are optional elements, and all of them reduce the iron loss of the non-oriented electrical steel sheet. Each element will be described below.

[0068] Zn: 0 to 0.0030% Zinc (Zn) is an optional element and does not necessarily need to be contained. That is, the Zn content may be 0%. When contained, that is, when the Zn content exceeds 0%, Zn suppresses the formation of oxides and sulfides and reduces the iron loss of the non-oriented electrical steel sheet. Even if even a small amount of Zn is contained, the above effect can be obtained to some extent. However, if the Zn content exceeds 0.0030%, the above effect saturates even if the contents of other elements are within the ranges of this embodiment. Therefore, the Zn content is 0 to 0.0030%. The preferred lower limit of the Zn content is 0.0001%, more preferably 0.0003%, and even more preferably 0.0005%. The preferred upper limit of the Zn content is 0.0025%, more preferably 0.0020%, and even more preferably 0.0015%.

[0069] Ge: 0 to 0.0030% Germanium (Ge) is an optional element and does not necessarily need to be contained. That is, the Ge content may be 0%. When contained, that is, when the Ge content exceeds 0%, Ge reduces the iron loss of the non-oriented electrical steel sheet. Ge also increases the magnetic flux density. Even if even a small amount of Ge is contained, the above effect can be obtained to some extent. However, if the Ge content exceeds 0.0030%, the above effect saturates even if the contents of other elements are within the ranges of this embodiment. Therefore, the Ge content is 0 to 0.0030%. The preferred lower limit of the Ge content is 0.0001%, more preferably 0.0003%, and even more preferably 0.0005%. The preferred upper limit of the Ge content is 0.0025%, more preferably 0.0020%, and even more preferably 0.0015%.

[0070] As: 0 to 0.0100% Arsenic (As) is an optional element and does not necessarily need to be contained. That is, the As content may be 0%. When contained, that is, when the As content exceeds 0%, As reduces the iron loss of the non-oriented electrical steel sheet. As also increases the magnetic flux density. Even if even a small amount of As is contained, the above effect can be obtained to some extent. However, if the As content exceeds 0.0100%, the above effect saturates even if the contents of other elements are within the ranges of this embodiment. Therefore, the As content is 0 to 0.0100%. The preferred lower limit of the As content is 0.0001%, more preferably 0.0005%, and even more preferably 0.0010%. The preferred upper limit of the As content is 0.0080%, more preferably 0.0060%, 0.0045%, and even more preferably 0.0040%.

[0071] Cobalt (Co) is an optional element and does not necessarily need to be contained. That is, the Co content may be 0%. When Co is contained, that is, when the Co content exceeds 0%, Co reduces the iron loss of the non-oriented electrical steel sheet. Co also increases the magnetic flux density. Even if even a small amount of Co is contained, the above effect can be obtained to some extent. However, if the Co content exceeds 0.0500%, the above effect saturates even if the contents of other elements are within the ranges of this embodiment. Therefore, the Co content is 0 to 0.0500%. The preferred lower limit of the Co content is 0.0001%, and more preferably 0.0010%. The preferred upper limit of the Co content is 0.0400%, more preferably 0.0300%, even more preferably 0.0200%, even more preferably 0.0100%, and even more preferably 0.0065%.

[0072] [Sixth Group: V, Se, Zr, Nb, Pb, and Ga] The chemical composition of the non-oriented electrical steel sheet according to this embodiment may further contain, in place of a portion of Fe, one or more elements selected from the group consisting of V, Se, Zr, Nb, Pb, and Ga. These elements are impurities that deteriorate iron loss. Each element will be described below.

[0073] V: 0 to 0.0030% Vanadium (V) is an impurity and may not be contained. That is, the V content may be 0%. When vanadium (V) is contained, that is, when the V content exceeds 0%, V forms fine precipitates and deteriorates the iron loss of the non-oriented electrical steel sheet. If the V content exceeds 0.0030%, the iron loss of the non-oriented electrical steel sheet will deteriorate significantly even if the contents of other elements are within the ranges of this embodiment. Therefore, the V content is 0 to 0.0030%. The V content is preferably as low as possible. However, excessive reduction of the V content increases manufacturing costs. Therefore, considering normal industrial production, the lower limit of the V content is preferably 0.0001%, more preferably 0.0003%, and even more preferably 0.0005%. The upper limit of the V content is preferably 0.0025%, more preferably 0.0020%, and even more preferably 0.0015%.

[0074] Se: 0 to 0.0030% Selenium (Se) is an impurity and may not be contained. That is, the Se content may be 0%. When contained, that is, when the Se content exceeds 0%, Se forms fine precipitates and deteriorates the iron loss of the non-oriented electrical steel sheet. If the Se content exceeds 0.0030%, the iron loss of the non-oriented electrical steel sheet will deteriorate significantly, even if the contents of other elements are within the ranges of this embodiment. Therefore, the Se content is 0 to 0.0030%. The Se content is preferably as low as possible. However, excessive reduction of the Se content increases manufacturing costs. Therefore, considering normal industrial production, the preferred lower limit of the Se content is 0.0001%, more preferably 0.0003%, and even more preferably 0.0005%. The preferred upper limit of the Se content is 0.0025%, more preferably 0.0020%, and even more preferably 0.0015%.

[0075] Zr: 0 to 0.0030% Zirconium (Zr) is an impurity and may not be contained. That is, the Zr content may be 0%. When contained, that is, when the Zr content exceeds 0%, Zr forms fine precipitates and deteriorates the iron loss of the non-oriented electrical steel sheet. If the Zr content exceeds 0.0030%, the iron loss of the non-oriented electrical steel sheet will deteriorate significantly, even if the contents of other elements are within the ranges of this embodiment. Therefore, the Zr content is 0 to 0.0030%. The Zr content is preferably as low as possible. However, excessive reduction of the Zr content increases manufacturing costs. Therefore, considering normal industrial production, the preferred lower limit of the Zr content is 0.0001%, more preferably 0.0003%, and even more preferably 0.0005%. The preferred upper limit of the Zr content is 0.0025%, more preferably 0.0020%, and even more preferably 0.0015%.

[0076] Nb: 0 to 0.0030% Niobium (Nb) is an impurity and may not be contained. That is, the Nb content may be 0%. If Nb is contained, that is, if the Nb content exceeds 0%, Nb forms fine precipitates and deteriorates the iron loss of the non-oriented electrical steel sheet. If the Nb content exceeds 0.0030%, the iron loss of the non-oriented electrical steel sheet will deteriorate significantly even if the contents of other elements are within the ranges of this embodiment. Therefore, the Nb content is 0 to 0.0030%. The Nb content is preferably as low as possible. However, excessive reduction of the Nb content increases manufacturing costs. Therefore, considering normal industrial production, the lower limit of the Nb content is preferably 0.0001%, more preferably 0.0003%, and even more preferably 0.0005%. The upper limit of the Nb content is preferably 0.0025%, more preferably 0.0020%, and even more preferably 0.0015%.

[0077] Pb: 0 to 0.0030% Lead (Pb) is an impurity and may not be present. That is, the Pb content may be 0%. If lead is present, that is, if the Pb content exceeds 0%, Pb forms fine Pb particles and deteriorates the iron loss of the non-oriented electrical steel sheet. If the Pb content exceeds 0.0030%, the iron loss of the non-oriented electrical steel sheet will deteriorate significantly, even if the contents of other elements are within the ranges of this embodiment. Therefore, the Pb content is 0 to 0.0030%. The lower the Pb content, the better. However, excessive reduction of the Pb content increases manufacturing costs. Therefore, considering normal industrial production, the preferred lower limit of the Pb content is 0.0001%, more preferably 0.0003%, and even more preferably 0.0005%. The preferred upper limit of the Pb content is 0.0025%, more preferably 0.0020%, and even more preferably 0.0015%.

[0078] Ga: 0 to 0.0030% Gallium (Ga) is an impurity and may not be contained. That is, the Ga content may be 0%. When contained, that is, when the Ga content exceeds 0%, Ga forms fine precipitates and deteriorates the core loss of the non-oriented electrical steel sheet. If the Ga content exceeds 0.0030%, the core loss of the non-oriented electrical steel sheet will deteriorate significantly, even if the contents of other elements are within the ranges of this embodiment. Therefore, the Ga content is 0 to 0.0030%. The Ga content is preferably as low as possible. However, excessive reduction of the Ga content increases manufacturing costs. Therefore, considering normal industrial production, the preferred lower limit of the Ga content is 0.0001%, more preferably 0.0003%, and even more preferably 0.0005%. The preferred upper limit of the Ga content is 0.0025%, more preferably 0.0020%, and even more preferably 0.0015%.

[0079] [Method for Measuring the Chemical Composition of Non-Oriented Electrical Steel Sheet] The chemical composition of the non-oriented electrical steel sheet of this embodiment can be measured by a well-known elemental analysis method in accordance with JIS G0321:2017. Specifically, chips are collected from the steel sheet using a drill. The collected chips are dissolved in acid to obtain a solution. The solution is subjected to ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometry) to perform elemental analysis of the chemical composition. The C content, S content, and O content are determined by a well-known high-frequency combustion method (combustion-infrared absorption method). The N content is determined using a well-known inert gas fusion-thermal conductivity method.

[0080] [(Feature 2) Regarding Sheet Thickness t] In the non-oriented electrical steel sheet of this embodiment, the sheet thickness t is 0.30 mm or less. Since the sheet thickness t is 0.30 mm or less, eddy current loss is reduced. The preferred lower limit of the sheet thickness t is 0.14 mm, more preferably 0.15 mm, even more preferably 0.19 mm, even more preferably 0.20 mm, even more preferably 0.21 mm, and even more preferably 0.24 mm. The preferred upper limit of the sheet thickness t is 0.29 mm, more preferably 0.27 mm, and even more preferably 0.25 mm.

[0081] [Method for measuring thickness t of non-oriented electrical steel sheet] The thickness t of a non-oriented electrical steel sheet is determined by the following method. The thickness is measured at 10 measurement positions on the non-oriented electrical steel sheet. All measurement positions are arranged on a line segment oriented in a direction tilted 45° from the rolling direction, and the distance between adjacent measurement points is 1.0 mm. The arithmetic mean value of the 10 measured thicknesses is taken as the thickness t (mm) of the non-oriented electrical steel sheet. The thickness is a value obtained by rounding the obtained arithmetic mean value to two decimal places. A micrometer is used for the measurement.

[0082] [(Feature 3) Regarding F1] In the non-oriented electrical steel sheet of this embodiment, F1 defined by formula (1) is 10.0 or more: F1=4Si+3Al+2Mn (1) where each element symbol in formula (1) is substituted with the content of the corresponding element in mass%.

[0083] F1 is an index relating to the resistivity of a non-oriented electrical steel sheet that satisfies Feature 1. If F1 is less than 10.0, a sufficiently high resistivity cannot be obtained even if the non-oriented electrical steel sheet satisfies the other features. As a result, the non-oriented electrical steel sheet does not achieve sufficiently low iron loss. If F1 is 10.0 or more, the non-oriented electrical steel sheet achieves sufficiently high resistivity, provided that the other features are satisfied. As a result, the non-oriented electrical steel sheet achieves excellent iron loss.

[0084] The preferred lower limit of F1 is 10.3, more preferably 10.5, even more preferably 11.5, even more preferably 12.0, and even more preferably 12.5. The upper limit of F1 is not particularly limited. However, if F1 is too high, the thermal conductivity of the non-oriented electrical steel sheet decreases. Therefore, the preferred upper limit of F1 is 17.0, more preferably 16.0, even more preferably 15.5, even more preferably 15.0, even more preferably 14.5, and even more preferably 14.0.

[0085] [(Feature 4) Regarding F2] In the non-oriented electrical steel sheet of this embodiment, F2 defined by formula (2) is 8.5 or less: F2=2Si+3Al+Mn (2) where the content of the corresponding element in mass% is substituted for each element symbol in formula (2).

[0086] F2 is an index relating to the saturation magnetic flux density of a non-oriented electrical steel sheet that satisfies Feature 1. If F2 exceeds 8.5, a sufficiently high magnetic flux density cannot be obtained even if the non-oriented electrical steel sheet satisfies the other features. Furthermore, if F2 exceeds 8.5, the thermal conductivity may further decrease. If F2 is 8.5 or less, a sufficiently high magnetic flux density can be obtained in the non-oriented electrical steel sheet, provided that the other features are satisfied.

[0087] The lower limit of F2 is preferably 5.0, more preferably 5.5, even more preferably 5.8, and even more preferably 6.0. The upper limit of F2 is preferably 8.3, more preferably 8.2, even more preferably 8.0, even more preferably 7.8, even more preferably 7.6, and even more preferably 7.5.

[0088] [(Feature 5) Regarding F3 and F4] In the non-oriented electrical steel sheet of the present embodiment, F3 defined by the formula (3) is further defined as the iron loss W ５／１０００ F4 defined by the formula (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T when a non-oriented electrical steel sheet is heat-treated at 800 ° C. for 1 hour. １０／４００That's all. F3 = 45 - 12Si - 5Al - 2Mn + 1000 x t / (5 + 6Si + 5Al + 3Mn) (3) F4 = 4 + 800 x t / (5 + 6Si + 5Al + 3Mn) (4) Here, the content of the corresponding element in mass% is substituted for each element symbol in formulas (3) and (4), and the plate thickness in mm is substituted for t. F3 and F4 will be explained below.

[0089] F3 and F4 are indices relating to the amount of strain and strain distribution in the metal structure of the non-oriented electrical steel sheet. As described above, in the non-oriented electrical steel sheet of this embodiment, in order to obtain high strength, high magnetic flux density, and excellent iron loss after stress relief annealing, the content of alloy elements in the steel sheet is intentionally kept low, and a specific amount of strain and strain distribution are introduced into the steel sheet. As a result, when a non-oriented electrical steel sheet used as a rotor core is used as a rotor core material without stress relief annealing, the manufactured rotor core can obtain high strength and excellent magnetic flux density. Furthermore, when a non-oriented electrical steel sheet used as a stator core is used as a stator core material after stress relief annealing, the manufactured stator core can obtain excellent iron loss and excellent magnetic flux density.

[0090] It is extremely difficult to quantitatively indicate the amount of strain and strain distribution in a steel sheet, so in this embodiment, F3 and F4 are used as indicators of the amount of strain and strain distribution in the steel sheet.

[0091] [Regarding F3] F3 is the iron loss W at a frequency of 1000 Hz and a magnetic flux density of 0.5 T ５／１０００ If F3 is greater than 0.05, the amount of strain introduced into the steel sheet is too small or the strain distribution in the steel sheet is inappropriate. Therefore, the non-oriented electrical steel sheet cannot obtain a sufficiently high strength. ５／１０００ If the strain is less than 1 / 2, a sufficient amount of strain is introduced into the steel sheet, and the distribution of the introduced strain is also appropriate. Therefore, in the case of a non-oriented electrical steel sheet, if Features 1 to 4 are satisfied and F4 is heat treated at 800°C for 1 hour, the iron loss W １０／４００ Assuming that the above is the case, a high magnetic flux density can be obtained.

[0092] The preferred lower limit of F3 is the iron loss W５／１０００ 0.40 times, and more preferably, the iron loss W ５／１０００ 0.50 times, and more preferably, the iron loss W ５／１０００ The preferred upper limit of F3 is 0.60 times the iron loss W ５／１０００ 0.90 times, and more preferably, the iron loss W ５／１０００ 0.87 times, and more preferably, the iron loss W ５／１０００ It is 0.85 times.

[0093] [Regarding F4] F4 is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T when a non-oriented electrical steel sheet is heat treated at 800°C for 1 hour. １０／４００ If the strain is less than 1 / 2, the amount of strain introduced into the steel sheet before stress relief annealing is not sufficiently reduced. Or, the distribution of strain in the steel sheet is inappropriate. In this case, a sufficiently low iron loss for stator applications cannot be obtained. Furthermore, since strain inhibits magnetization, the magnetic flux density B １ decreases.

[0094] Iron loss W when F4 is heat treated at 800°C for 1 hour １０／４００ If the above conditions are met, a sufficient amount of strain can be reduced from the steel sheet, and the distribution of the introduced strain is also appropriate. Therefore, in the case of non-oriented electrical steel sheets, Features 1 to 4 are satisfied, and F3 is the iron loss W ５／１０００ Provided that the following is true, excellent core loss and excellent magnetic flux density can be obtained in the non-oriented electrical steel sheet after stress relief annealing.

[0095] The preferred lower limit of F4 is the iron loss W １０／４００ 1.01 times, and more preferably, the iron loss W １０／４００ 1.02 times, and more preferably, the iron loss W １０／４００ The preferred upper limit of F4 is 1.05 times the iron loss W １０／４００ 1.50 times, and more preferably, the iron loss W １０／４００ 1.40 times, and more preferably, the iron loss W １０／４００ It is 1.30 times.

[0096] [Iron loss W of non-oriented electrical steel sheet ５／１０００ Measurement method for iron loss W of the non-oriented electrical steel sheet of this embodiment ５／１０００is determined by the Epstein test method shown below. In accordance with JIS C 2550-1:2011 and 2550-3:2019, multiple Epstein test pieces are cut out from the non-oriented electrical steel sheet. The size of the Epstein test piece is 30 mm wide and 280 mm long. As the Epstein test pieces, multiple L-direction test pieces are cut out, the longitudinal direction of which is the rolling direction of the non-oriented electrical steel sheet, and multiple C-direction test pieces are cut out, the longitudinal direction of which is perpendicular to the rolling direction of the non-oriented electrical steel sheet. The number of L-direction test pieces and the number of C-direction test pieces are the same, and the total number of each type of test piece is 16 (8 L-direction test pieces and 8 C-direction test pieces).

[0097] The L-direction test pieces and the C-direction test pieces are placed in an Epstein frame. Assuming that the four sides of the Epstein frame are parallel to the X direction or the Y direction, four L-direction test pieces are placed on each of a pair of sides parallel to the X direction. Four C-direction test pieces are placed on each of a pair of sides parallel to the Y direction. The ends of the L-direction test pieces and the ends of the C-direction test pieces are stacked so that they overlap each other alternately. This results in the L-direction test pieces and the C-direction test pieces being assembled in a square shape. The Epstein test pieces assembled in a square shape were subjected to the electromagnetic steel strip test method in accordance with JIS C 2550-1:2011 and 2550-3:2019, and the iron loss W at 1000 Hz and 0.5 T was measured. ５／１０００ (W / kg) is measured.

[0098] [Iron loss W after stress relief annealing of non-oriented electrical steel sheet １０／４００ Measurement method for iron loss W after stress relief annealing of the non-oriented electrical steel sheet of this embodiment １０／４００ is calculated by the following method. ５／１０００According to the method described in [Measurement method for the L-direction test piece], multiple Epstein test pieces (8 L-direction test pieces and 8 C-direction test pieces) are cut out from the non-oriented electrical steel sheet. The cut Epstein test pieces (L-direction test pieces and C-direction test pieces) are subjected to heat treatment (stress relief annealing). In the heat treatment, the heat treatment temperature is 800°C, and the holding time at the heat treatment temperature is 1 hour. Note that the temperature and time are based on the temperature of the Epstein test piece itself, not the temperature of the annealing furnace (furnace temperature). Stress relief annealing is performed with the Epstein test pieces stacked. The temperature of the Epstein test pieces is measured using a thermocouple.

[0099] For temperature measurement, the test Epstein test specimens and the same number of temperature-measurement Epstein test specimens as the test Epstein test specimens are loaded into the same heat treatment furnace and heat-treated simultaneously. Specifically, a test Epstein test specimen set consisting of a stack of multiple test Epstein test specimens and a temperature-measurement Epstein test specimen set consisting of a stack of multiple temperature-measurement Epstein test specimens are prepared. The insulating coating of the Epstein test specimen (steel plate) located at the center of the stacking direction of the temperature-measurement Epstein test specimen set is removed with sandpaper (#240). A thermocouple is welded to the location where the insulating coating was removed. The temperature-measurement Epstein test specimen set with the welded thermocouple is heat-treated simultaneously with the test Epstein test specimen set. At this time, the temperature measured by the thermocouple of the temperature-measurement Epstein test specimen set is considered to be the temperature of the test Epstein test specimen set.

[0100] During the heat treatment, it is not necessary to fix the multiple Epstein test pieces in the test Epstein test piece set to one another, and it is not necessary to fix the multiple Epstein test pieces in the temperature measurement Epstein test piece set to one another. If the stacking of the multiple Epstein test pieces for temperature measurement becomes unstable due to the insertion of thermocouples in the Epstein test piece set for temperature measurement, each longitudinal end of the Epstein test piece set for temperature measurement may be tied and fixed with a stainless steel wire or the like having a diameter of about 0.3 mm.

[0101] The Epstein test specimens (L-direction test specimens and C-direction test specimens) were heated to 800°C and then placed in the Epstein frame.５／１０００ Similarly to the method described in [Measurement method for L-direction test pieces], four L-direction test pieces are placed on each of a pair of sides parallel to the X direction of the Epstein frame. Four C-direction test pieces are placed on each of a pair of sides parallel to the Y direction. The ends of the L-direction test pieces and the ends of the C-direction test pieces are stacked so that they overlap each other alternately. This results in the L-direction test pieces and C-direction test pieces being assembled in a square shape. The Epstein test pieces assembled in a square shape are subjected to the electromagnetic steel strip test method in accordance with JIS C 2550-1:2011 and 2550-3:2019 to measure the iron loss W at 400 Hz and 1.0 T. １０／４００ Measure.

[0102] [Effects of the Non-oriented Electrical Steel Sheet of the Present Embodiment] The non-oriented electrical steel sheet of the present embodiment satisfies Features 1 to 5. Therefore, the non-oriented electrical steel sheet of the present embodiment has high strength and excellent magnetic flux density. Furthermore, the non-oriented electrical steel sheet of the present embodiment has excellent iron loss after stress relief annealing.

[0103] [Regarding strength] The non-oriented electrical steel sheet of this embodiment can achieve even higher strength. Specifically, the non-oriented electrical steel sheet of this embodiment has a yield stress of 450 MPa or more. A preferred lower limit of the yield stress is 460 MPa, more preferably 470 MPa, and even more preferably 480 MPa. The upper limit of the yield stress is not particularly limited. However, in the non-oriented electrical steel sheet of this embodiment, the upper limit of the yield stress is, for example, 530 MPa.

[0104] [Method for Measuring Yield Stress] The yield stress of the non-oriented electrical steel sheet of this embodiment is measured by the following method. A JIS No. 5 tensile test piece, as specified in JIS Z 2241:2011, is taken from the non-oriented electrical steel sheet. A tensile test is performed at room temperature and atmospheric pressure using the taken tensile test piece in accordance with JIS Z 2241:2011 to obtain the yield stress (MPa). Note that if an upper yield point appears on the stress-strain curve obtained by the tensile test, the yield stress is taken as the upper yield point (MPa). If no upper yield point appears on the obtained stress-strain curve, the yield stress is taken as the 0.2% proof stress (MPa).

[0105] [Regarding magnetic flux density] The non-oriented electrical steel sheet of this embodiment provides excellent magnetic flux density. Specifically, the magnetic flux density B ５０ A, B ５０ (0°), B ５０ (22.5°), B ５０ (45°), B ５０ (67.5°) and B ５０ (90°), the average magnetic flux density B defined by equation (5) ５０ａｖｅ is 1.65T or more. ５０ａｖｅ = (B ５０ (0°) + 2 x B ５０ (22.5°) + 2 x B ５０ (45°) + 2 x B ５０ (67.5°) + B ５０ (90°)) / 8 (5)

[0106] [Average magnetic flux density B ５０ａｖｅ Measurement method for average magnetic flux density B ５０ａｖｅ is determined by the following method: Epstein test pieces are prepared for non-oriented electrical steel sheets in the rolling direction (L direction), 22.5°, 45°, and 67.5° directions from the rolling direction, and a direction perpendicular to the rolling direction (90° direction, i.e., C direction), and the magnetic flux density B ５０ The test method basically complies with JIS C 2550-1 (2011). Epstein test pieces extending in the L direction, 22.5° direction, 45° direction, 67.5° direction, and C direction are cut out in one set for each direction. For each set of Epstein test pieces cut out in the same direction, the magnetic steel strip test method compliant with JIS C 2550-1 (2011) and 2550-3 (2011) is carried out, and the magnetic flux density B at 5000 A / m in each direction is measured. ５０ The magnetic flux density B in each direction is measured. ５０ Substituting into equation (5), the average magnetic flux density B ５０ａｖｅ (T) is obtained.

[0107] Preferably, in the non-oriented electrical steel sheet of this embodiment, when the non-oriented electrical steel sheet is heat treated at 800°C for 1 hour, the magnetic flux density B１ A, B １ (0°), B １ (22.5°), B １ (45°), B １ (67.5°) and B １ (90°), the average magnetic flux density B defined by equation (6) １ａｖｅ is 0.70 T or more, and the magnetic flux density B ５００ The magnetic flux density B in each angle direction at 22.5° pitch when the direction of the maximum value is set as the reference 0° ５００ A, B ５００ (0°), B ５００ (22.5°), B ５００ (45°), B ５００ (67.5°) and B ５００ (90°), the average magnetic flux density B defined by equation (7) ５００ａｖｅ is 1.98T or more. B １ａｖｅ = (B １ (0°) + 2 x B １ (22.5°) + 2 x B １ (45°) + 2 x B １ (67.5°) + B １ (90°)) / 8 (6) B ５００ａｖｅ = (B ５００ (0°) + 2 x B ５００ (22.5°) + 2 x B ５００ (45°) + 2 x B ５００ (67.5°) + B ５００ (90°)) / 8 (7)

[0108] Average magnetic flux density B when non-oriented electrical steel sheet is heat treated at 800°C for 1 hour １ａｖｅ is 0.70 T or more, and the average magnetic flux density B ５００ａｖｅ If the magnetic flux density is 1.98 T or more, sufficient magnetic flux density can be obtained in an electric vehicle during high-speed driving when the magnetic field applied to the motor is lowest, during city driving when the magnetic field applied to the motor is higher than during high-speed driving but lower than when climbing a slope, and during climbing a slope when the magnetic field applied to the motor is highest.

[0109] [Average magnetic flux density B １ａｖｅ Measurement method for average magnetic flux density B １ａｖｅis determined by the following method. Epstein test pieces are prepared for a non-oriented electrical steel sheet in the rolling direction (L direction), in the direction of 22.5°, 45°, and 67.5° from the rolling direction, and in the direction perpendicular to the rolling direction (90° direction, i.e., C direction). The non-oriented electrical steel sheet is heat treated (stress relief annealing) at 800°C for 1 hour. The magnetic flux density B in each direction is measured using the Epstein test pieces after the heat treatment. １ The test method basically complies with JIS C 2550-1 (2011). Epstein test pieces extending in the L direction, 22.5° direction, 45° direction, 67.5° direction, and C direction are subjected to the magnetic steel strip test method in accordance with JIS C 2550-1 (2011) and 2550-3 (2011) for each set of Epstein test pieces in the same direction, and the magnetic flux density B at 100 A / m in each direction is measured. １ The magnetic flux density B in each direction is measured. １ Substituting into equation (6), the average magnetic flux density B １ａｖｅ (T) is obtained.

[0110] [Average magnetic flux density B ５００ａｖｅ Measurement method for average magnetic flux density B ５００ａｖｅ is determined by the following method. Epstein test pieces are prepared for a non-oriented electrical steel sheet in the rolling direction (L direction), in the direction of 22.5°, 45°, and 67.5° from the rolling direction, and in the direction perpendicular to the rolling direction (90° direction, i.e., C direction). The non-oriented electrical steel sheet is heat treated (stress relief annealing) at 800°C for 1 hour. The magnetic flux density B in each direction is measured using the Epstein test pieces after the heat treatment. ５００ The test method basically complies with JIS C 2550-1 (2011). Epstein test pieces extending in the L direction, 22.5° direction, 45° direction, 67.5° direction, and C direction are subjected to the magnetic steel strip test method in accordance with JIS C 2550-1 (2011) and 2550-3 (2011) for each set of Epstein test pieces in the same direction, and the magnetic flux density B at 50,000 A / m in each direction is measured. ５００ The magnetic flux density B in each direction is measured. ５００ Substituting into equation (7), the average magnetic flux density B ５００ａｖｅ (T) is obtained.

[0111] [Regarding Iron Loss] The non-oriented electrical steel sheet of this embodiment exhibits excellent iron loss after stress relief annealing. Specifically, the iron loss W １０／４００ is less than F4W / kg.

[0112] [Regarding Other Characteristics] [Regarding Thermal Conductivity] The non-oriented electrical steel sheet of this embodiment also has high thermal conductivity. Specifically, the non-oriented electrical steel sheet of this embodiment has a thermal conductivity of 20 W / mK or more at 20°C and a thermal conductivity of 23 W / mK or more at 150°C.

[0113] In this case, the rotor core and stator core manufactured using the non-oriented electrical steel sheet of this embodiment have high thermal conductivity, which prevents the motor core from overheating during operation, thereby preventing demagnetization of the magnets in the motor core.

[0114] [Method for measuring thermal conductivity] The thermal conductivity of a non-oriented electrical steel sheet can be measured by the following method. The thermal conductivity of a non-oriented electrical steel sheet can be calculated as the product of the thermal diffusion coefficient, density, and specific heat. Therefore, the thermal diffusion coefficient, density, and specific heat of a non-oriented electrical steel sheet are calculated by the following method. A laser flash analyzer is used to determine the thermal diffusion coefficient of the non-oriented electrical steel sheet. Specifically, a test piece of 6 mm diameter x thickness is taken from the center of the sheet width of the non-oriented electrical steel sheet. One surface of the test piece is irradiated with a laser pulse using the laser flash analyzer. At this time, the temperature change on the other surface is detected with an infrared detector. The time-series change in temperature is obtained. The thermal diffusion equation is used to calculate the thermal diffusion coefficient (m ２ / seconds).

[0115] Furthermore, the density of the non-oriented electrical steel sheet is determined based on the Archimedes method. Specifically, a test piece measuring 100 mm x 100 mm x sheet thickness is taken from the center of the sheet width of the non-oriented electrical steel sheet. The mass of the test piece when dry is determined. Next, the test piece is immersed in a water tank. The mass of the test piece in the immersed state (i.e., when subjected to the buoyancy of water) is determined. These results and the specific gravity of water are used to determine the specific gravity of the test piece (non-oriented electrical steel sheet).

[0116] Furthermore, the specific heat of the non-oriented electrical steel sheet is determined using a differential scanning calorimeter. Specifically, a test piece measuring 6 mm diameter and thickness is taken from the center of the sheet width of the non-oriented electrical steel sheet. The test piece is placed on the sample pan of the differential scanning calorimeter. A substance with a known specific heat is used as a reference sample. The temperature of the test piece and the temperature of the reference sample are changed at a constant rate, and the specific heat of the test piece (non-oriented electrical steel sheet) is determined based on the difference in temperature change between the two. Based on the obtained thermal diffusion coefficient, specific gravity, and specific heat of the non-oriented electrical steel sheet, the thermal conductivity (W / mK) at 20°C and the thermal conductivity (W / mK) at 150°C of the non-oriented electrical steel sheet are determined.

[0117] [Regarding fracture elongation] The non-oriented electrical steel sheet of this embodiment is further excellent in fracture elongation. Specifically, the non-oriented electrical steel sheet of this embodiment has a fracture elongation of 20% or more. The non-oriented electrical steel sheet of this embodiment is excellent in fracture elongation. Therefore, when manufacturing a motor core by stacking multiple motor core materials (rotor core materials or stator core materials described below) formed by processing non-oriented electrical steel sheets, it becomes possible to fix the overlapping motor core materials by caulking, without using an adhesive.

[0118] As described above, the non-oriented electrical steel sheet of this embodiment provides excellent elongation at break. Therefore, when a motor core material is manufactured using the non-oriented electrical steel sheet of this embodiment as a starting material, crimping can be performed even if the sheet thickness is 0.30 mm or less. A motor core formed by laminating the motor core material provides excellent iron loss.

[0119] The breaking elongation can be determined based on the stress-strain curve obtained by carrying out a tensile test according to the method described in the above-mentioned [Method for measuring yield stress].

[0120] [Method for manufacturing non-oriented electrical steel sheet] An example of a method for manufacturing a non-oriented electrical steel sheet of this embodiment will be described. The example of a method for manufacturing a non-oriented electrical steel sheet of this embodiment includes the following steps: (Step 1) Hot rolling step (Step 2) Hot-rolled sheet annealing step (Step 3) Cold rolling step (Step 4) Finish annealing step Note that the hot-rolled sheet annealing step of step 2 is an optional step, and may or may not be performed. Each step will be described below.

[0121] [(Step 1) Hot Rolling Step] In the hot rolling step, a slab is hot rolled to produce a hot-rolled steel sheet. The slab has a chemical composition such that the chemical composition of the produced non-oriented electrical steel sheet satisfies Feature 1. The slab is produced by a well-known method. For example, the slab is produced by a continuous casting method using molten steel having the above-mentioned chemical composition.

[0122] The prepared slab is subjected to hot rolling. Preferably, the conditions of the hot rolling step are appropriately adjusted depending on whether or not the subsequent hot-rolled sheet annealing step is performed. For example, when the hot-rolled sheet annealing step is not performed (i.e., when self-annealing is performed), the preferred slab heating temperature in the hot rolling step is 1200°C to 1250°C, the preferred finish rolling temperature is 1050°C or higher, and the preferred coiling temperature is 750°C or lower. For example, when hot-rolled sheet annealing is performed, the preferred slab heating temperature in the hot rolling step is 1100°C to 1150°C, the preferred finish rolling temperature is 850°C or lower, and the preferred coiling temperature is 700°C or lower.

[0123] [(Step 2) Hot-rolled sheet annealing step] The hot-rolled sheet annealing step is an optional step. In other words, the hot-rolled sheet annealing step does not have to be performed. When the hot-rolled sheet annealing step is performed and box annealing is performed as the hot-rolled sheet annealing, the preferred heat treatment temperature is 800°C or higher, and the preferred soaking time at the heat treatment temperature is 10 hours or longer. When continuous annealing is performed as the hot-rolled sheet annealing, the preferred heat treatment temperature is 950°C or higher, and the preferred soaking time at the heat treatment temperature is 30 seconds or longer. If necessary, a well-known pickling treatment may be performed on the steel sheet before annealing in the hot-rolled sheet annealing step and / or on the steel sheet after annealing.

[0124] [(Step 3) Cold Rolling Step] In the cold rolling step, cold rolling is performed on the hot-rolled steel sheet produced in the hot rolling step or the hot-rolled steel sheet after the hot-rolled sheet annealing step to produce a cold-rolled steel sheet. Cold rolling may be performed once or multiple times. When cold rolling is performed multiple times, well-known intermediate annealing may be performed after cold rolling and before the next cold rolling is performed.

[0125] [(Step 4) Finish Annealing Step] Finish annealing is performed on the cold-rolled steel sheet produced by the cold rolling step to produce a non-oriented electrical steel sheet. In the finish annealing, the cold-rolled steel sheet finished to the final sheet thickness is annealed to recrystallize and grow crystal grains. The finish annealing step includes a temperature increase step, a soaking step in which the steel sheet is soaked at a maximum temperature T1 (°C), and a cooling step in which the steel sheet is cooled after the soaking step. The finish annealing step satisfies the following conditions 1 to 3. (Condition 1) Annealing is performed at a maximum temperature T1 of 900°C or less. (Condition 2) The lower of the maximum temperature T1 (°C) and 800°C is referred to as the maximum strain-affecting temperature T2 (°C). In the cooling step, the temperature range from the maximum temperature T2 to 500°C is referred to as the strain-imparting temperature range. The tension TE (kgf / mm ２ ) satisfies the following formula (A): 1.0 ≥ TE ≥ 1.2 - T2 / 1000 (A) where TE in formula (A) is the tension (kgf / mm ２) is substituted. When tension changes in the strain-applying temperature range, the maximum value of tension in the strain-applying temperature range is substituted for TE in formula (A). Note that when tension is applied to a steel sheet during the cooling process to introduce strain, the strain is likely to disappear due to recovery in a temperature range of 800°C or higher. Therefore, the strain-affecting maximum reachable temperature T2 is set to the lower temperature (°C) of the maximum reachable temperature T1 and 800°C. (Condition 3) The maximum reachable temperature T1, tension TE, strain-affecting maximum temperature T2, and the average cooling rate CR (°C / sec) from the strain-affecting maximum temperature T2 to 500°C in the cooling process satisfy formula (B). LOG{(T2-500) / CR-5}×TE≧0.02 (B) Here, the strain-affecting maximum temperature T2 (°C) is substituted for T2 in formula (B). The average cooling rate CR (°C / sec) is substituted for CR. The tension (kgf / mm ２ ) is substituted. When the tension changes in the strain-applying temperature range, the maximum value of the tension in the strain-applying temperature range is substituted for TE in formula (B). Each condition will be explained below.

[0126] [(Condition 1) Regarding the maximum temperature T1] The maximum temperature T1 is set to 900°C or less. If the maximum temperature T1 exceeds 900°C, the amount of strain and the strain distribution in the manufactured non-oriented electrical steel sheet will not be appropriate. As a result, F3 will be W ５／１０００ or iron loss W when F4 is heat treated at 800 ° C for 1 hour １０／４００ If the maximum temperature T1 is 900°C or less, the amount of strain and the strain distribution in the manufactured non-oriented electrical steel sheet are appropriate. ５／１０００ When F4 is heat treated at 800°C for 1 hour, the iron loss W １０／４００ The lower limit of the maximum temperature T1 is, for example, 700°C.

[0127] [(Condition 2) Formula (A)] In the strain-imparting temperature range during the cooling process, the tension TE imparted to the steel sheet is adjusted to satisfy the following formula (A): 1.0 ≥ TE ≥ 1.2 - T2 / 1000 (A).

[0128] The tension TE applied to the steel sheet in the strain-applying temperature range affects the amount of strain and strain distribution of the manufactured non-oriented electrical steel sheet.

[0129] FA is defined as follows: FA = 1.2 - T2 / 1000 Tension TE (kgf / mm ２ If F3 is less than FA, the amount and distribution of strain imparted to the steel sheet in the strain-applying temperature range will be inappropriate. ５／１０００ or iron loss W when F4 is heat treated at 800 ° C for 1 hour １０／４００ Tension TE (kgf / mm ２ ) is FA or more, the amount and distribution of strain imparted to the steel sheet in the strain imparting temperature range will be in an appropriate range. ５／１０００ When F4 is heat treated at 800°C for 1 hour, the iron loss W １０／４００ That's all.

[0130] On the other hand, the tension TE is 1.0 kgf / mm ２ If F3 is greater than W, excessive strain is introduced in the strain application temperature range, resulting in more dislocation pair annihilation. In this case, the amount of strain is insufficient and an appropriate strain distribution is not formed. ５／１０００ or iron loss W when F4 is heat treated at 800 ° C for 1 hour １０／４００ It will be less than.

[0131] [Regarding (Condition 3) Formula (B)] To introduce an appropriate amount of strain into a non-oriented electrical steel sheet and form an appropriate strain distribution, it is necessary to apply an appropriate tension TE for an appropriate time in the strain application temperature range. Here, RS is defined as follows: RS = LOG{(T2 - 500) / CR - 5} x TE ≥ 0.02 (B) Here, the maximum temperature T2 (°C) at which strain is affected is substituted for T2 in formula (B). The average cooling rate CR (°C / sec) is substituted for CR. TE is the tension (kgf / mm) applied to the steel sheet in the strain application temperature range. ２ ) is substituted.

[0132] If RS is less than 0.02, the time during which tension is applied in the temperature range where strain is applied, satisfying condition 2, is too short. In this case, the amount of strain accumulated in the non-oriented electrical steel sheet is insufficient, and an appropriate strain distribution is not formed. ５／１０００ or iron loss W when F4 is heat treated at 800 ° C for 1 hour １０／４００ If RS is 0.02 or more, the amount of strain accumulated in the non-oriented electrical steel sheet is appropriate, assuming that other conditions are met, and an appropriate strain distribution is formed. As a result, F3 is ５／１０００ The iron loss W when F4 is heat treated at 800 ° C for 1 hour is as follows. １０／４００ That's all.

[0133] [Other Steps] In the above-described manufacturing method, a coating step may be carried out after the final annealing step. In the coating step, an insulating coating is applied to the surface of the non-oriented electrical steel sheet after the final annealing. The type of insulating coating is not particularly limited. The insulating coating may be an organic component, an inorganic component, or a mixture of an organic component and an inorganic component.

[0134] The non-oriented electrical steel sheet of this embodiment can be manufactured by the above manufacturing method. Note that the manufacturing method of the non-oriented electrical steel sheet of this embodiment is not particularly limited as long as it satisfies Features 1 to 5.

[0135] [Regarding the rotor core] The rotor core of this embodiment is manufactured using the non-oriented electrical steel sheet of this embodiment as a material. Fig. 1A is a plan view showing an example of a rotor core 1. Referring to Fig. 1A, the rotor core 1 includes a plurality of rotor core materials 10. The rotor core materials 10 are plate-shaped. The rotor core 1 is configured by stacking the plurality of rotor core materials 10.

[0136] The shape of the rotor core is not particularly limited as long as it is plate-shaped. Fig. 1A shows a rotor core for a permanent magnet synchronous motor as an example. In Fig. 1A, a rotor core material 10 is disk-shaped and includes a plurality of through holes 11 arranged in the circumferential direction. Permanent magnets (not shown) are disposed in the through holes 11. The rotor core material 10 further includes a through hole 13 in the center. A motor shaft (not shown) is inserted into the through hole 13.

[0137] Although Fig. 1A shows the rotor core for a permanent magnet synchronous motor, the rotor core may have any other shape as long as it is plate-shaped. For example, if the motor is a reluctance motor, the rotor core may be plate-shaped with multiple salient poles 15 as shown in Fig. 1B, or disk-shaped with multiple through holes 16 that serve as flux barriers as shown in Fig. 1C. Furthermore, if the motor is an induction motor, the rotor core may have multiple through holes in which induced current paths made of copper or aluminum die-cast are installed.

[0138] The rotor core material 10 is manufactured by punching the non-oriented electrical steel sheet of this embodiment. Therefore, the rotor core material 10 satisfies Features 1 to 5. Therefore, the rotor core 1 has high strength. The rotor core 1 also has excellent magnetic flux density. The rotor core material 10 also has excellent breaking elongation. Specifically, the breaking elongation of the rotor core material 10 is 20% or more.

[0139] [Method for measuring magnetic properties of rotor core material] The magnetic flux density and iron loss of the rotor core material can be measured based on the single sheet magnetic property test (SST) specified in JIS C 2556:2015.

[0140] Specifically, the rotor core blank is separated from the rotor core. If the rotor core blanks are fixed together with an adhesive, the rotor core blank may be heated to a temperature range of 300 to 450°C to soften the adhesive, and then the rotor core blank may be separated from the rotor core.

[0141] SST test pieces are taken from the separated rotor core material. Note that wire cutting is used to take the SST test pieces to avoid processing strain. The SST test pieces are, for example, 55 mm x 55 mm x plate thickness.

[0142] If it is not possible to obtain SST test pieces measuring 55 mm x 55 mm x thickness from the rotor core material, two L-direction SST test pieces measuring 16 mm in the L direction (rolling direction) x 8 mm width x thickness are obtained, and two C-direction SST test pieces measuring 16 mm in the C direction (direction perpendicular to the rolling direction) x 8 mm width x thickness are obtained. For L-direction iron loss measurements, the two L-direction SST test pieces are arranged in a 16 mm x 16 mm square and the test is conducted. For C-direction iron loss measurements, the two C-direction SST test pieces are arranged in a 16 mm x 16 mm square and the test is conducted.

[0143] Using the SST test piece, the iron loss in the L direction W ５／１０００（Ｌ） (W / kg) and iron loss in the C direction W ５／１０００（Ｃ） (W / kg) Iron loss in L direction W ５／１０００（Ｌ） (W / kg) and iron loss in the C direction W ５／１０００（Ｃ） The arithmetic mean value of (W / kg) is the iron loss W ５／１０００（Ｌ＋Ｃ） (W / kg). The obtained iron loss W ５／１０００（Ｌ＋Ｃ） is converted into a value measured using an Epstein tester specified in JIS C 2550-1:2011 and JIS C 2550-3:2019, and used as an Epstein equivalent value.

[0144] The Epstein equivalent value can be determined by the following method. An Epstein test piece and an SST test piece are taken in advance from the same non-oriented electrical steel sheet. The Epstein test piece is subjected to the above-mentioned [Iron loss W of non-oriented electrical steel sheet]. ５／１０００ The iron loss W ５／１０００（ＥＰ） The above-mentioned SST test is carried out on the SST test piece to determine the iron loss W ５／１０００（Ｌ＋Ｃ） (W / kg) is calculated. ５／１０００（ＥＰ） (W / kg) and iron loss W in SST test specimen ５／１０００（Ｌ＋Ｃ） Based on the weight loss (W / kg), the conversion factor K is calculated using the following formula: K = (iron loss W in Epstein test piece)５／１０００（ＥＰ） ) / (Iron loss in SST test piece W ５／１０００（Ｌ＋Ｃ） )

[0145] The measured values ​​of the rotor core obtained by the SST test (iron loss W ５／１０００（Ｌ＋Ｃ） ) is multiplied by the above K to obtain the iron loss W equivalent to Epstein ５／１０００ (W / kg). The Epstein equivalent value is calculated as the iron loss W of the rotor core. ５／１０００ (W / kg).

[0146] If an Epstein test piece cannot be taken from the rotor core material, the density of the rotor core material, the magnetic flux density B50 in the SST test, and the iron loss W ５／１０００（Ｌ＋Ｃ） Substantially the same density, magnetic flux density B50 and iron loss W ５／１０００（Ｌ＋Ｃ） Specifically, the density of the prepared non-oriented electrical steel sheet is within ±1% of the density of the rotor core material, and the iron loss W obtained by the SST test piece is ５／１０００（Ｌ＋Ｃ） The iron loss W obtained from the SST test piece of the rotor core material ５／１０００（Ｌ＋Ｃ） The magnetic flux density B50 obtained by the SST test piece is within the range of B50 ±2% obtained by the SST test piece of the rotor core material. ５／１０００ The iron loss W was measured using an Epstein test piece by a method conforming to the measurement method of ５／１０００（ＥＰ） The obtained iron loss W ５／１０００（ＥＰ） (W / kg) is the Epstein equivalent value.

[0147] Preferably, the rotor core material 10 may further include a crimped portion 12 and a flat portion 14, as also shown in Figures 1A to 1C. The crimped portion 12 is a recess formed in the rotor core material 10. When a plurality of rotor core materials 10 are stacked, the crimped portions 12 of the rotor core materials 10 that are stacked one above the other fit together and are fixed to each other. The flat portion 14 is a flat region, different from the crimped portion 12. The flat portion 14 is a portion that becomes the base material of the rotor core material 10, and the thickness of the flat portion 14 corresponds to the thickness of the non-oriented electrical steel sheet that is the material.

[0148] When the rotor core 1 is formed using the crimped portions 12, there is no need to fix the rotor core materials 10 together with an adhesive. When the rotor core materials 10 are fixed together with an adhesive, compressive stress is applied to the rotor core materials 10 due to volumetric shrinkage when the adhesive solidifies. This compressive stress deteriorates the iron loss of the rotor core 1. On the other hand, when the rotor core materials 10 are fixed together using the crimped portions 12, compressive stress like that applied with an adhesive is not applied.

[0149] 2A is a cross-sectional view of the crimped portion 12 in FIG. 1A taken along line IIA-IIA (X direction). FIG. 2B is a cross-sectional view of the crimped portion 12 in FIG. 1A taken along line IIB-IIB (Y direction). Referring to FIGS. 2A and 2B, the crimped portion 12 includes a pair of inclined portions 121. The inclined portions 121 are formed so as to be inclined with respect to the flat portion 14 of the rotor core blank 10. The crimped portion 12 may include a bottom portion 122 between the pair of inclined portions 121. Alternatively, the crimped portion 12 may be a so-called V-shaped crimp in which the lower ends of the pair of inclined portions 121 are connected to each other without including the bottom portion 122. By including the inclined portions 121, the crimped portion 12 increases the fixing force due to fitting.

[0150] The cross-sectional shape of the crimped portion 12 is not limited to the shape shown in FIG. 2B or a V-shape. For example, it may be a U-shape or a W-shape. The crimped portion 12 may also be an N-shape. As long as the crimped portion 12 includes the inclined portion 121, the cross-sectional shape of the crimped portion 12 is not particularly limited.

[0151] The inclined portion 121 of the crimped portion 12 corresponds to the portion of the rotor core material 10 where the thickness is the thinnest. １２１ is the plate thickness PT of the flat portion 14 of the rotor core material 10 １４ The thickness of the flat portion 14 is 85% or less. １４ corresponds to the thickness t of the non-oriented electrical steel sheet used as the material.

[0152] As described above, in this embodiment, the thickness PT of the inclined portion 121 of the crimped portion 12 １２１ is the plate thickness PT of the flat portion 14 １４Therefore, the inclination angle of the inclined portion 121 relative to the flat portion 14 can be made steeper. As a result, the size of the inclined portion 12 when the rotor core material 10 is viewed from above can be kept small. Furthermore, by making the inclination angle of the inclined portion 121 relative to the flat portion 14 steeper, the fixing force when fitted is increased.

[0153] When forming the crimped portion 12 including the inclined portion 121, the plate thickness of the inclined portion 121 becomes thin. Therefore, the rotor core material 10 needs to have a degree of ductility that allows the inclined portion 121 to be formed. As described above, the rotor core material 10 satisfies Features 1 to 5, and therefore has excellent breaking elongation. Therefore, the plate thickness PT １２１ is the plate thickness PT of the flat portion 14 １４ Therefore, the crimped portion 12 can be formed including the inclined portion 121 that is 85% or less of the original length.

[0154] Preferably, the thickness PT of the inclined portion 121 １２１ is the plate thickness PT of the flat portion 14 １４ Preferably, the thickness PT is 83% or less, and more preferably 80% or less. １２１ is plate thickness PT １４ It is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more.

[0155] Preferably, the Vickers hardness H １４ The Vickers hardness H １２１ Is H １４ +40 HV or more. As described above, the rotor core material 10 satisfies Features 1 to 5. Therefore, it has excellent strength. As a result, the Vickers hardness of the crimped portion 12 and the Vickers hardness of the flat portion 14 are also high.

[0156] [Plate thickness PT of flat portion 14 １４ and the thickness PT of the inclined portion 121 １２１ Measurement method for thickness PT of flat portion 14 １４ and the thickness PT of the inclined portion 121 １２１is obtained by the following method: A test piece including the cross section of FIG. 2B is taken from one rotor core material 10. The thickness of the flat portion 14 is measured at any five points on the flat portion 14, and the arithmetic mean value of the five obtained values ​​is defined as the thickness PT of the flat portion 14. １４ (mm) Plate thickness PT １４ The value (mm) is a value obtained by rounding off the fourth decimal place of the obtained arithmetic mean value to three decimal places. Furthermore, the thickness is measured at five arbitrary points of the inclined portion 121, and the obtained five arithmetic mean values ​​are used as the thickness PT of the inclined portion 121. １２１ (mm) Plate thickness PT １２１ The value (mm) is the value obtained by rounding off the fourth decimal place of the obtained arithmetic mean value to three decimal places. Measurement may be performed using a micrometer or a non-contact measuring device such as a laser triangulation type plate thickness measuring device.

[0157] [Vickers hardness H of the flat portion 14 １４ and the Vickers hardness H of the inclined portion 121 １２１ Measurement method for Vickers hardness H of flat portion 14 １４ and the Vickers hardness H of the inclined portion 121 １２１ is obtained by the following method. A test piece including the cross section of FIG. 2B is taken from the rotor core material 10. A Vickers hardness test according to JIS Z 2244-1:2020 is carried out at five arbitrary positions at the center of the plate thickness of the inclined portion 121 on the cross section of the test piece. The test force is 1 N. If the Vickers hardness tester can only control the test force in kgf units, the test force is 0.1 kgf. The arithmetic mean value of the obtained Vickers hardness is taken as the Vickers hardness H of the inclined portion 121. １２１ (HV) Vickers hardness H １２１ (HV) is an integer value obtained by rounding off the obtained arithmetic mean value to one decimal place.

[0158] Similarly, a Vickers hardness test according to JIS Z 2244-1:2020 is carried out at five arbitrary central positions of the thickness of the flat portion 14 of the cross section of the test piece. The test force is 1 N. If the Vickers hardness tester can only control the test force in kgf units, the test force is 0.1 kgf. The arithmetic mean value of the obtained Vickers hardness is taken as the Vickers hardness H of the flat portion 14.１４ Vickers hardness (HV) is １４ (HV) is an integer value obtained by rounding off the obtained arithmetic mean value to one decimal place.

[0159] [Regarding the Stator Core] The stator core of this embodiment is manufactured using the non-oriented electromagnetic steel sheet of this embodiment as a material. FIG. 3 is a plan view of the stator core 2. Referring to FIG. 3, the stator core 2 includes a plurality of stator core materials 20. The stator core materials 20 are in the shape of circular ring plates. The stator core 2 is configured by stacking a plurality of stator core materials 20. The stator core material 20 includes a plurality of teeth 21. The plurality of teeth 21 are arranged with gaps between each other in the circumferential direction of the stator core material 20. The teeth 21 extend in the radial direction of the stator core material 20.

[0160] The stator core material 20 is manufactured by punching the non-oriented electrical steel sheet of this embodiment and then performing stress relief annealing. Therefore, the stator core material 20 satisfies Features 1 to 4, and further, F4 defined in Equation (4) is smaller than the iron loss W １０／４００ As a result, the stator core 2 has excellent magnetic flux density and excellent iron loss. Furthermore, the stator core material 20, in the state after punching and before stress relief annealing, has excellent breaking elongation, similar to the rotor core material 10. Specifically, the breaking elongation of the stator core material 20 is 20% or more.

[0161] [Method for Measuring Magnetic Properties of Stator Core Material] The magnetic flux density and iron loss of the stator core material can be measured based on the Single Sheet Tester (SST) specified in JIS C 2556:2015. Specifically, the stator core material is separated from the stator core. If the stator core materials are fixed together with an adhesive, the stator core material may be heated to a temperature range of 300 to 450°C to soften the adhesive, and then the stator material may be separated from the stator core. SST test pieces are taken from the separated stator core material. Note that wire cutting is used to take the SST test pieces to avoid processing distortion. The SST test pieces are, for example, 55 mm x 55 mm x thickness.

[0162] If it is not possible to obtain SST test pieces measuring 55 mm x 55 mm x thickness from the stator core material, two L-direction SST test pieces measuring 16 mm in the L direction (rolling direction) x 8 mm width x thickness are obtained, and two C-direction SST test pieces measuring 16 mm in the C direction (direction perpendicular to the rolling direction) x 8 mm width x thickness are obtained. For iron loss measurement in the L direction, the two L-direction SST test pieces are arranged in a 16 mm x 16 mm square and the test is conducted. For iron loss measurement in the C direction, the two C-direction SST test pieces are arranged in a 16 mm x 16 mm square and the test is conducted.

[0163] Using the SST test piece, the iron loss in the L direction W ５／１０００（Ｌ） (W / kg) and iron loss in the C direction W ５／１０００（Ｃ） (W / kg) Iron loss in L direction W ５／１０００（Ｌ） (W / kg) and iron loss in the C direction W ５／１０００（Ｃ） The arithmetic mean value of (W / kg) is the iron loss W ５／１０００（Ｌ＋Ｃ） (W / kg). The obtained iron loss W ５／１０００（Ｌ＋Ｃ） is converted into a value measured using an Epstein tester specified in JIS C 2550-1:2011 and JIS C 2550-3:2019, and used as an Epstein equivalent value.

[0164] The Epstein equivalent value can be determined by the following method. An Epstein test piece and an SST test piece are taken in advance from the same non-oriented electrical steel sheet. The Epstein test piece is subjected to the above-mentioned [Iron loss W of non-oriented electrical steel sheet]. ５／１０００ The iron loss W ５／１０００（ＥＰ） The above-mentioned SST test is carried out on the SST test piece to determine the iron loss W ５／１０００（Ｌ＋Ｃ） (W / kg) is calculated. ５／１０００（ＥＰ） (W / kg) and iron loss W in SST test specimen ５／１０００（Ｌ＋Ｃ） Based on the weight loss (W / kg), the conversion factor K is calculated using the following formula: K = (iron loss W in Epstein test piece) ５／１０００（ＥＰ） ) / (Iron loss in SST test piece W ５／１０００（Ｌ＋Ｃ） )

[0165] The measured values ​​of the stator obtained by the SST test (iron loss W ５／１０００（Ｌ＋Ｃ） ) is multiplied by the above K to obtain the iron loss W equivalent to Epstein ５／１０００ (W / kg). The Epstein equivalent value is calculated as the iron loss W of the stator core. ５／１０００ (W / kg).

[0166] If an Epstein test piece cannot be taken from the stator core material, the density of the stator core material, the magnetic flux density B50 in the SST test, and the iron loss W ５／１０００（Ｌ＋Ｃ） Substantially the same density, magnetic flux density B50 and iron loss W ５／１０００（Ｌ＋Ｃ） Specifically, the density of the prepared non-oriented electrical steel sheet is within ±1% of the density of the rotor core material, and the iron loss W obtained by the SST test piece is ５／１０００（Ｌ＋Ｃ） The iron loss W obtained from the SST test piece of the rotor core material ５／１０００（Ｌ＋Ｃ） The magnetic flux density B50 obtained by the SST test piece is within the range of B50 ±2% obtained by the SST test piece of the rotor core material. ５／１０００ The iron loss W was measured using an Epstein test piece by a method conforming to the measurement method of ５／１０００（ＥＰ） The obtained iron loss W ５／１０００（ＥＰ） (W / kg) is the Epstein equivalent value.

[0167] Preferably, the stator core material 20 may further include a flat portion 24 and a crimped portion 22, as shown in Fig. 3. The crimped portion 22 is a recess formed in the stator core material 20. When a plurality of stator core materials 20 are stacked, the crimped portions 22 of the stator core materials 20 that are stacked one above the other fit together and are fixed to each other. In other words, the crimped portion 22 plays the same role as the crimped portion 12. Unlike the crimped portion 22, the flat portion 24 is a flat region. The flat portion 24 is a portion that becomes the base material of the stator core material 20, and the thickness of the flat portion 24 corresponds to the thickness of the non-oriented electromagnetic steel sheet that is the material.

[0168] When the stator core 2 is formed using the crimped portions 22, there is no need to fix the stator core materials 20 together with an adhesive. Therefore, when the stator core materials 20 are fixed together using the crimped portions 22, compressive stress, which is the case with adhesives, is not applied. In the case of the stator core 2, after the multiple stator core materials 20 are fixed together with the crimped portions 22, strain relief annealing is performed. Therefore, strain introduced into the crimped portions 22 when the crimped portions 22 were formed is also removed. As a result, not only is compressive stress, which is the case when an adhesive is used, not applied to the stator core 2, but the influence of strain when the crimped portions 22 are formed is also sufficiently suppressed. Therefore, the stator core 2 has excellent iron loss.

[0169] The configuration of the crimped portion 22 is the same as that of the crimped portion 12. Referring to Figures 2A and 2B, the crimped portion 22 includes a pair of inclined portions 221. The inclined portions 221 are formed at an angle relative to the portions of the stator core material 20 other than the crimped portion 22. The crimped portion 22 may include a bottom portion 222 between the pair of inclined portions 221. Alternatively, the crimped portion 22 may be a so-called V-shaped crimp in which the lower ends of the pair of inclined portions 221 are connected without including the bottom portion 222. By including the inclined portions 221, the crimped portion 22 has an increased fixing force due to fitting.

[0170] Similarly to the crimped portion 12, the crimped portion 22 may be, for example, U-shaped or W-shaped. The crimped portion 22 may also be N-shaped. As long as the crimped portion 22 includes the inclined portion 221, the cross-sectional shape of the crimped portion 22 is not particularly limited.

[0171] The inclined portion 221 of the crimped portion 22 corresponds to the thinnest portion of the stator core material 20. ２２１ is the plate thickness PT of the flat portion 24, which is the portion other than the crimped portion 22 of the stator core material 20. ２４ The thickness PT of the flat portion 24 is 85% or less. ２４ corresponds to the thickness t of the non-oriented electrical steel sheet used as the material.

[0172] As described above, in this embodiment, the thickness PT of the inclined portion 221 of the crimped portion 22 ２２１ is the plate thickness PT of the flat portion 24 ２４ Therefore, the inclination angle of the inclined portion 221 relative to the flat portion 24 can be made steeper. As a result, the size of the inclined portion 22 when the stator core material 20 is viewed from above can be kept small. Furthermore, by making the inclination angle of the inclined portion 221 relative to the flat portion 24 steeper, the fixing force when fitted is increased.

[0173] When forming the crimped portion 22 including the inclined portion 221, the plate thickness of the inclined portion 221 becomes thin. Therefore, the stator core material 20 needs to have a degree of ductility that allows the inclined portion 221 to be formed. As described above, the stator core material 20 satisfies Features 1 to 4, and further, F4 defined in Equation (4) is smaller than the iron loss W １０／４００ Therefore, the sheet thickness PT ２２１ is the plate thickness PT of the flat portion 24 ２４ Therefore, the crimped portion 22 can be formed including the inclined portion 221 that is 85% or less of the original length.

[0174] Preferably, the thickness PT of the inclined portion 221 ２２１ is the plate thickness PT of the flat portion 24 ２４ Preferably, the thickness PT is 83% or less, and more preferably 80% or less. ２２１ is plate thickness PT ２４It is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more.

[0175] Preferably, the Vickers hardness H at the center of the thickness of the flat portion 24 of the stator core material 20 is ２４ is 175 Hv or more, and the Vickers hardness H ２２１ is the Vickers hardness H of the flat portion 24 ２４ The hardness is ±10 HV or less. The stator core material 20 has been subjected to stress relief annealing, so that strain is removed, resulting in low hardness.

[0176] [Plate thickness PT of flat portion 24 ２４ and the thickness PT of the inclined portion 221 ２２１ Measurement method for thickness PT of flat portion 24 ２４ and the thickness PT of the inclined portion 221 ２２１ is obtained by the following method: A test piece including the cross section of FIG. 2B is taken from one rotor core material 10. The thickness of the flat portion 24 is measured at any five points on the flat portion 24, and the arithmetic mean value of the five obtained values ​​is defined as the thickness PT of the flat portion 24. ２４ (mm) Plate thickness PT ２４ The arithmetic mean value (mm) is an integer obtained by rounding off the first decimal place of the obtained arithmetic mean value. Furthermore, the thickness is measured at any five points of the inclined portion 221, and the obtained five arithmetic mean values ​​are used as the thickness PT of the inclined portion 221. ２２１ (mm) Plate thickness PT ２２１ The thickness (mm) is an integer value obtained by rounding off the obtained arithmetic mean value to the nearest tenth. Measurement may be performed using a micrometer or a non-contact measuring device such as a laser triangulation type plate thickness measuring instrument.

[0177] [Vickers hardness H of the flat portion 24 ２４ and the Vickers hardness H of the inclined portion 221 ２２１ Measurement method for Vickers hardness H of flat portion 24 ２４ and the Vickers hardness H of the inclined portion 221 ２２１is obtained by the following method. A test piece including the cross section of FIG. 2B is taken from the stator core material 20. A Vickers hardness test according to JIS Z 2244-1:2020 is carried out at five arbitrary positions at the center of the thickness of the inclined portion 221 of the cross section of the test piece. The test force is 1 N. If the Vickers hardness tester can only control the test force in kgf units, the test force is 0.1 kgf. The arithmetic mean value of the obtained Vickers hardness is taken as the Vickers hardness H of the inclined portion 221. ２２１ (HV) Vickers hardness H ２２１ (HV) is an integer value obtained by rounding off the obtained arithmetic mean value to one decimal place.

[0178] Similarly, a Vickers hardness test according to JIS Z 2244-1:2020 is carried out at five arbitrary points at the center of the thickness of the flat portion 24 of the cross section of the test piece. The test force is 1 N. The arithmetic mean value of the obtained Vickers hardness values ​​is defined as the Vickers hardness H of the flat portion 24. ２４ (HV) Vickers hardness H ２４ (HV) is an integer value obtained by rounding off the obtained arithmetic mean value to one decimal place.

[0179] [Method of Manufacturing Rotor Core 1 and Stator Core 2] The rotor core 1 and stator core 2 are manufactured by the following method. The rotor core material 10 and the stator core material 20 are manufactured by punching from the non-oriented electromagnetic steel sheet of this embodiment. Before punching, the crimped portion 12 is formed by pressing in the region that will become the rotor core material 10. Similarly, the crimped portion 22 is formed by pressing in the region that will become the stator core material 20.

[0180] After the crimped portions 12 are formed, the rotor core blank 10 is continuously punched out. At this time, a newly punched rotor core blank 10 is stacked on top of the punched rotor core blank 10, and the crimped portions 12 are fitted together. In other words, the stacking and fitting of the rotor core blanks 10 is also carried out while the punching process is being carried out. The rotor core 1 is manufactured through the above steps.

[0181] Similarly, after forming the crimped portions 22, the stator core blanks 20 are continuously punched out. At this time, newly punched stator core blanks 20 are stacked on top of the punched stator core blanks 20, and the crimped portions 22 are fitted together. In other words, the stacking and fitting of the stator core blanks 20 is also carried out while the punching process is being carried out. Stress relief annealing is carried out on the stacked multiple stator core blanks 20. Stress relief annealing is carried out, for example, at 800 to 850°C for 1 to 10 hours. The stator core 2 is manufactured through the above steps.

[0182] [Regarding the Motor] The motor of this embodiment includes the rotor core and the stator core described above. Because the motor of this embodiment includes the rotor core and stator core of this embodiment, the rotor core has high strength. The motor of this embodiment also has excellent magnetic flux density and iron loss.

[0183] Non-oriented electrical steel sheets having the chemical compositions shown in Table 1 (Table 1A, Table 1B, and Table 1C) were produced by the following method.

[0184]

[0185]

[0186]

[0187] The slabs (steel billets) were hot-rolled to produce hot-rolled steel sheets with a thickness of 2.0 mm. The slab heating temperature was 1100°C to 1150°C. The finish rolling temperature was 800°C or higher and 850°C or lower. The coiling temperature was 700°C or lower. The hot-rolled steel sheets were subjected to hot-rolled sheet annealing by soaking at 1000°C for 1 minute. The steel sheets after the hot-rolled sheet annealing were cold-rolled to produce cold-rolled steel sheets with various thicknesses.

[0188] The cold-rolled steel sheets thus produced were subjected to final annealing. The maximum temperature T1 (°C) and tension TE (kgf / mm ２), average cooling rate CR (°C / sec), and RS are shown in Table 2. In the "1.0 ≥ TE ≥ FA" column in Table 2, "T" means that formula (A) is satisfied. "F" means that formula (A) is not satisfied. Non-oriented electrical steel sheets of each test number were manufactured by the above manufacturing process. The sheet thickness (mm) of each test number is shown in the "Sheet thickness t (mm)" column in Table 2. Furthermore, F1 to F4 of each test number are shown in the "F1", "F2", "F3" and "F4" columns of Table 2, respectively. In Table 2, "F3 ≤ W ５／１０００ "T" in the "" column indicates that F3 is iron loss W ５／１０００ "F" means that F3 is the iron loss W ５／１０００ It means that we have surpassed the １０／４００ "T" in the "≦F4" column indicates the W value when F4 is heat treated at 800°C for 1 hour. １０／４００ "F" means that F4 is heat treated at 800°C for 1 hour. １０／４００ means less than.

[0189]

[0190] [Evaluation Tests] The following evaluation tests were carried out on the non-oriented electrical steel sheets with each test number: (Test 1) Chemical composition measurement test (Test 2) Sheet thickness measurement test (Test 3) Iron loss measurement test (Test 4) Yield stress and fracture elongation measurement test (Test 5) Magnetic flux density measurement test (Test 6) Thermal conductivity measurement test Tests 1 to 6 are explained below.

[0191] [(Test 1) Chemical Composition Measurement Test] The chemical composition of the non-oriented electrical steel sheet of each test number was measured based on the method described in the above-mentioned [Method for measuring the chemical composition of non-oriented electrical steel sheet]. As a result, the chemical composition of the non-oriented electrical steel sheet of each test number was as shown in Table 1.

[0192] [(Test 2) Sheet Thickness Measurement Test] The sheet thickness of the non-oriented electrical steel sheet of each test number was measured based on the method described in the above-mentioned [Method for measuring sheet thickness t of non-oriented electrical steel sheet]. The measurement results are shown in the "Sheet thickness t (mm)" column in Table 2.

[0193] [(Test 3) Iron Loss Measurement Test] The above-mentioned [Iron Loss W of Non-oriented Electrical Steel Sheet] ５／１０００Based on the measurement method, the iron loss W of the non-oriented electrical steel sheet of each test number ５／１０００ (W / kg) was calculated. ５／１０００ The iron loss W ５／１０００ Furthermore, the above-mentioned "Iron loss W of non-oriented electrical steel sheet after stress relief annealing" is shown in the "(W / kg)" column. １０／４００ Based on the measurement method of the non-oriented electrical steel sheet of each test number, the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T when heat treated at 800 ° C for 1 hour was measured. １０／４００ The iron loss W １０／４００ The iron loss after stress relief annealing W in Table 3 １０／４００ (W / kg)" column.

[0194]

[0195] [(Test 4) Yield Stress and Breaking Elongation Measurement Test] The yield stress (MPa) of the non-oriented electrical steel sheet of each test number was determined based on the above-mentioned [Yield Stress Measurement Method]. The obtained yield stress is shown in the "Yield Stress (MPa)" column in Table 3. Furthermore, the breaking elongation (%) of the non-oriented electrical steel sheet of each test number was determined from the stress-strain curve obtained by the [Yield Stress Measurement Method]. The obtained breaking elongation is shown in the "Breaking Elongation (%)" column in Table 3.

[0196] [(Test 5) Magnetic Flux Density Measurement Test] ５０ａｖｅ Based on the measurement method of the average magnetic flux density B of the non-oriented electrical steel sheet of each test number ５０ａｖｅ (T) was obtained. The obtained average magnetic flux density B ５０ａｖｅ (T) in Table 3 ５０ａｖｅ Furthermore, the above-mentioned [average magnetic flux density B １ａｖｅ Based on the measurement method of the average magnetic flux density B of the non-oriented electrical steel sheet of each test number １ａｖｅ (T) was obtained. The obtained average magnetic flux density B １ａｖｅ (T) in Table 3 １ａｖｅ Furthermore, the above-mentioned [average magnetic flux density B ５００ａｖｅ Based on the measurement method of the average magnetic flux density B of the non-oriented electrical steel sheet of each test number ５００ａｖｅ (T) was obtained. The obtained average magnetic flux density B ５００ａｖｅ (T) in Table 3５００ａｖｅ (T)" column.

[0197] [(Test 6) Thermal Conductivity Measurement Test] Based on the above-mentioned [Method for Measuring Thermal Conductivity], the thermal conductivity (W / mK) at 20°C and the thermal conductivity (W / mK) at 150°C of the non-oriented electrical steel sheet of each test number were determined. The obtained thermal conductivities at 20°C and 150°C are shown in Table 3 in the "20°C Thermal Conductivity (W / mK)" and "150°C Thermal Conductivity (W / mK)" columns.

[0198] [Evaluation Results] Referring to Tables 1 to 3, test numbers 1 to 29 satisfied characteristics 1 to 5. Therefore, the yield strength was 450 MPa or more, and high strength was obtained. Furthermore, the average magnetic flux density B ５０ａｖｅ The magnetic flux density was 1.65 T or more, and an excellent magnetic flux density was obtained. 1０／4００ However, the F4W / kg was less than F4W / kg, and excellent iron loss was obtained after stress relief annealing.

[0199] In addition, in these test numbers 1 to 29, the average magnetic flux density B １ａｖｅ is 0.70 T or more, and the average magnetic flux density B ５００ａｖｅ The thermal conductivity at 20° C. was 20 W / mK or more, and the thermal conductivity at 150° C. was 23 W / mK or more, so excellent thermal conductivity was obtained.

[0200] On the other hand, in test numbers 30 and 31, F1 did not satisfy formula (1), and therefore sufficient iron loss was not obtained after stress relief annealing.

[0201] In test numbers 32 and 33, F2 did not satisfy formula (2). Therefore, sufficient magnetic flux density was not obtained. In addition, in test number 33, the thermal conductivity at 20°C and 150°C was low. This is thought to be because F1 was high.

[0202] In test numbers 34 and 35, the maximum temperature T1 reached in the final annealing process exceeded 900°C. ５／１０００ As a result, sufficient yield strength and elongation at break were not obtained.

[0203] In test numbers 36 and 37, the tension TE during the final annealing process was less than FA. Therefore, F3 did not satisfy formula (3), and F4 did not satisfy formula (4). As a result, sufficient yield strength was not obtained. Furthermore, the average magnetic flux density B after stress relief annealing １ａｖｅ was less than 0.70 T, and a sufficient magnetic flux density was not obtained.

[0204] In test numbers 38 and 39, the tension TE during the final annealing process was 1.0 kgf / mm ２ Therefore, F3 did not satisfy formula (3), and F4 did not satisfy formula (4). As a result, sufficient yield strength was not obtained. Furthermore, the average magnetic flux density B １ａｖｅ was less than 0.70 T, and a sufficient magnetic flux density was not obtained.

[0205] In test numbers 40 and 41, RS did not satisfy formula (B). Therefore, F3 did not satisfy formula (3), and F4 did not satisfy formula (4). As a result, sufficient yield strength was not obtained. Furthermore, the average magnetic flux density B after stress relief annealing １ａｖｅ was less than 0.70 T, and a sufficient magnetic flux density was not obtained.

[0206] Using the non-oriented electrical steel sheets of each test number in Table 1, rotor core materials having the shape shown in FIG. 1A and stator core materials having the shape shown in FIG. 3 were manufactured. Specifically, the non-oriented electrical steel sheets of each test number were punched to manufacture the rotor core materials. Furthermore, the non-oriented electrical steel sheets of each test number were punched to manufacture intermediate materials for the stator core materials. The intermediate materials were subjected to stress relief annealing at 800°C for 1 hour to manufacture the stator core materials.

[0207] The following evaluation tests were conducted on the rotor core material and stator core material with each test number: (Test 7) ​​Magnetic property evaluation test (Test 8) Measurement test of thickness of inclined portion of crimped portion and thickness of flat portion (Test 9) Measurement test of hardness of inclined portion of crimped portion and hardness of flat portion Tests 7 to 9 are explained below.

[0208] [(Test 7) ​​Magnetic Property Evaluation Test] Based on the method described in the above [Method for Measuring Magnetic Properties of Rotor Core Material], the iron loss W of the rotor core material of each test number was measured. ５／１０００ The iron loss (W / kg) was calculated. The size of the test piece was 16 mm x width 8 mm x thickness. ５／１０００ (W / kg) is shown in Table 4A. Furthermore, based on the method described in [Method for measuring magnetic properties of stator core material], the iron loss W １０／４００ The iron loss (W / kg) was calculated. The size of the test piece was 16 mm x width 8 mm x thickness. １０／４００ (W / kg) is shown in Table 4B.

[0209]

[0210]

[0211] [(Test 8) Measurement test of thickness of inclined portion of crimped portion and thickness of flat portion] １４ and the thickness PT of the inclined portion 121 １２１ Based on the method described in [Measuring Method of the Flat Part 14 of the Rotor Core Material], １４ and the thickness PT of the inclined portion 121 １２１ Furthermore, the thickness PT of the flat portion 24 was calculated. ２４ and the thickness PT of the inclined portion 221 ２２１ Based on the method described in [Method of measuring the thickness PT of the flat portion 24 of the stator core material], ２４ and the thickness PT of the inclined portion 221 ２２１ The obtained plate thickness PT １４ (mm), plate thickness PT １２１ (mm), plate thickness PT ２４ (mm) and plate thickness PT ２２１ (mm) are shown in Table 4 (Table 4A and Table 4B).

[0212] [(Test 9) Hardness Measurement Test of the Inclined Portion and the Flat Portion of the Crimped Portion] The above-mentioned [Vickers hardness H of the flat portion 14] １４ and the Vickers hardness H of the inclined portion 121 １２１ The Vickers hardness H of the flat portion 14 of the rotor core material was measured based on the method described in the measurement method for the Vickers hardness H of the flat portion 14 of the rotor core material. １４and the Vickers hardness H of the inclined portion 121 １２１ Furthermore, the Vickers hardness H ２４ and the Vickers hardness H of the inclined portion 221 ２２１ The Vickers hardness H of the flat portion 24 of the stator core material was measured based on the method described in the measurement method for the Vickers hardness H of the flat portion 24 of the stator core material. ２４ and the Vickers hardness H of the inclined portion 221 ２２１ The obtained Vickers hardness H １４ (HV), Vickers hardness H １２１ (HV), Vickers hardness H ２４ (HV), Vickers hardness H ２２１ (HV) is shown in Table 4.

[0213] [Evaluation Results] Referring to Table 4 (Table 4A and Table 4B), in the rotor core materials of test numbers 1 to 29, which are examples of the present invention, the thickness of the inclined portion is 85% or less of the thickness of the flat portion, and the Vickers hardness H １４ is 180 HV or more, and the Vickers hardness H １２１ H １４ In addition, in the stator core materials of test numbers 1 to 29, which are examples of the present invention, the thickness of the inclined portion is 85% or less of the thickness of the flat portion, and the Vickers hardness H ２４ is 175 HV or more, and the Vickers hardness H ２２１ is the Vickers hardness H ２４ It was ±10 HV or less.

[0214] The embodiments of the present disclosure have been described above. However, the above-described embodiments are merely examples for implementing the present disclosure. Therefore, the present disclosure is not limited to the above-described embodiments, and can be implemented by appropriately modifying the above-described embodiments within the scope of the present disclosure.

Claims

1. A non-oriented electrical steel sheet having a chemical composition, in mass%, of Si: 2.0 to 4.0%, Mn: 0.1 to 1.5%, P: 0.15% or less, S: 0.0030% or less, Al: 0.1 to 2.0%, C: 0.0050% or less, N: 0.0050% or less, O: 0.0500% or less, Cr: 0 to 0.50%, Ti: 0 to 0.0030%, Mo: 0 to 0.100%, Ni: 0 to 0.50%, Cu: 0 to 0.50%, Sn: 0 to 0.100%, Sb: 0 to 0.100%, Ca: 0 to 0.0050%, Mg: 0 to 0.0030%, rare earth elements: 0 to 0.0100%, B: 0 to 0.0030%, Zn: 0 to 0.0030%, Ge: 0 to 0.0030%, As: 0 to 0.0100%, Co: 0 to 0.0500%, V: 0 to 0.0030%, Se: 0 to 0.0030%, Zr: 0 to 0.0030%, Nb: 0 to 0.0030%, Pb: 0 to 0.0030%, and Ga: 0 to 0.0030%, with the balance being Fe and impurities; a sheet thickness t is 0.30 mm or less; F1 defined by formula (1) is 10.0 or more; F2 defined by formula (2) is 8.5 or less; F3 defined in equation (3) is the iron loss W at a frequency of 1000 Hz and a magnetic flux density of 0.5 T. ５／１０００ F4 defined by the formula (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T when the non-oriented electrical steel sheet is heat-treated at 800°C for 1 hour. １０／４００ Non-oriented electrical steel sheet having the above formulas: F1 = 4Si + 3Al + 2Mn (1) F2 = 2Si + 3Al + Mn (2) F3 = 45 - 12Si - 5Al - 2Mn + 1000 x t / (5 + 6Si + 5Al + 3Mn) (3) F4 = 4 + 800 x t / (5 + 6Si + 5Al + 3Mn) (4) Here, the element symbols in formulas (1) to (4) are substituted with the content of the corresponding element in mass%, and t is substituted with the sheet thickness in mm.

2. A non-oriented electrical steel sheet according to claim 1, wherein the chemical composition is: Cr: 0.01 to 0.50%, Ti: 0.0001 to 0.0030%, Mo: 0.001 to 0.100%, Ni: 0.01 to 0.50%, Cu: 0.01 to 0.50%, Sn: 0.001 to 0.100%, Sb: 0.001 to 0.100%, Ca: 0.0001 to 0.0050%, Mg: 0.0001 to 0.0030%, rare earth elements: 0.0001 to 0.0100%, B: 0.0001 to 0.0030%, Zn: 0.0001 to 0.0030%, A non-oriented electrical steel sheet containing one or more elements selected from the group consisting of Ge: 0.0001 to 0.0030%, As: 0.0001 to 0.0100%, Co: 0.0001 to 0.0500%, V: 0.0001 to 0.0030%, Se: 0.0001 to 0.0030%, Zr: 0.0001 to 0.0030%, Nb: 0.0001 to 0.0030%, Pb: 0.0001 to 0.0030%, and Ga: 0.0001 to 0.0030%.

3. A non-oriented electrical steel sheet according to claim 1, having a yield stress of 450 MPa or more and a fracture elongation of 20% or more.

4. The non-oriented electrical steel sheet according to claim 1, wherein the magnetic flux density B in the direction of each angle at a pitch of 22.5° when the rolling direction is set as the reference 0° ５０ A, B ５０ (0°), B ５０ (22.5°), B ５０ (45°), B ５０ (67.5°) and B ５０ (90°), the average magnetic flux density B defined by equation (5) ５０ａｖｅ A non-oriented electrical steel sheet having a strength of 1.65T or more. ５０ａｖｅ = (B ５０ (0°) + 2 x B ５０ (22.5°) + 2 x B ５０ (45°) + 2 x B ５０ (67.5°) + B ５０ (90°)) / 8 (5) 5. The non-oriented electrical steel sheet according to claim 1, wherein when the non-oriented electrical steel sheet is heat treated at 800°C for 1 hour, the iron loss W １０／４００ is F4 or less, and the magnetic flux density B in the direction of each angle at a pitch of 22.5° when the rolling direction is set as the reference 0° １ A, B １ (0°), B １ (22.5°), B １ (45°), B １ (67.5°) and B １ (90°), the average magnetic flux density B defined by equation (6) １ａｖｅ is 0.70 T or more, and the magnetic flux density B ５００ The magnetic flux density B in the direction of each angle at a pitch of 22.5° when the direction of the maximum value of ５００ A, B ５００ (0°), B ５００ (22.5°), B ５００ (45°), B ５００ (67.5°) and B ５００ (90°), the average magnetic flux density B defined by equation (7) ５００ａｖｅ A non-oriented electrical steel sheet having a hardness of 1.98T or more. １ａｖｅ = (B １ (0°) + 2 x B １ (22.5°) + 2 x B １ (45°) + 2 x B １ (67.5°) + B １ (90°)) / 8 (6) B ５００ａｖｅ = (B ５００ (0°) + 2 x B ５００ (22.5°) + 2 x B ５００ (45°) + 2 x B ５００ (67.5°) + B ５００ (90°)) / 8 (7) 6. A non-oriented electrical steel sheet according to claim 1, wherein the thermal conductivity at 20°C is 20 W / mK or more, and the thermal conductivity at 150°C is 23 W / mK or more.

7. A rotor core material comprising a plurality of laminated rotor core materials, each of which is plate-shaped, and which has a chemical composition, in mass %, of Si: 2.0 to 4.0%, Mn: 0.1 to 1.5%, P: 0.15% or less, S: 0.0030% or less, Al: 0.1 to 2.0%, C: 0.0050% or less, N: 0.0050% or less, O: 0.0500% or less, Cr: 0 to 0.50%, Ti: 0 to 0.0030%, Mo: 0 to 0.100%, Ni: 0 to 0.50%, Cu: 0 to 0.50%, Sn: 0 to 0.100%, Sb: 0 to 0.100%, Ca: 0 to 0.0050%, Mg: 0 to 0.0030%, rare earth elements: 0 to 0.0100%, B: 0 to 0.0030%, Zn: 0 to 0.0030%, Ge: 0 to 0.0030%, As: 0 to 0.0100%, Co: 0 to 0.0500%, V: 0 to 0.0030%, Se: 0 to 0.0030%, Zr: 0 to 0.0030%, Nb: 0 to 0.0030%, Pb: 0 to 0.0030%, and Ga: 0 to 0.0030%, with the balance being Fe and impurities, the sheet thickness t is 0.30 mm or less, F1 defined by formula (1) is 10.0 or more, and F2 defined by formula (2) is 8.5 or less, F3 defined in equation (3) is the iron loss W at a frequency of 1000 Hz and a magnetic flux density of 0.5 T. ５／１０００ F4 defined by the formula (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T when the rotor core material is heat-treated at 800°C for 1 hour. １０／４００ The rotor core is as follows: F1 = 4Si + 3Al + 2Mn (1) F2 = 2Si + 3Al + Mn (2) F3 = 45 - 12Si - 5Al - 2Mn + 1000 x t / (5 + 6Si + 5Al + 3Mn) (3) F4 = 4 + 800 x t / (5 + 6Si + 5Al + 3Mn) (4) Here, the element symbols in formulas (1) to (4) are substituted with the content of the corresponding element in mass%, and t is substituted with the plate thickness in mm.

8. A rotor core as set forth in claim 7, wherein the rotor core material further includes a crimped portion and a flat portion which is a flat region, the crimped portion includes an inclined portion formed at an angle relative to the flat portion, and the thickness of the inclined portion is 85% or less of the thickness of the flat portion.

9. A rotor core according to claim 8, wherein in a cross section including a central axis of the rotor core material, a Vickers hardness H １４ is 180 HV or more, and the Vickers hardness H １２１ Is H １４ A rotor core that is +40HV or higher.

10. A stator core material includes a plurality of stacked stator core materials, each of which has an annular plate shape, and includes a plurality of teeth arranged with gaps in the circumferential direction of the stator core material and extending in the radial direction of the stator core material, and the stator core material has a chemical composition, in mass %, of Si: 2.0 to 4.0%, Mn: 0.1 to 1.5%, P: 0.15% or less, S: 0.0030% or less, Al: 0.1 to 2.0%, C: 0.0050% or less, N: 0.0050% or less, O: 0.0500% or less, Cr: 0 to 0.50%, Ti: 0 to 0.0030%, Mo: 0 to 0.100%, Ni: 0 to 0.50%, Cu: 0 to 0.50%, Sn: 0-0.100%, Sb: 0-0.100%, Ca: 0-0.0050%, Mg: 0-0.0030%, rare earth elements: 0-0.0100%, B: 0-0.0030%, Zn: 0-0.0030%, Ge: 0-0.0030%, As: 0-0.0100%, Co: 0-0.0500%, V: 0-0.0030%, Se: 0-0.0030%, Zr: 0-0.0030%, Nb: 0-0.0030%, Pb: 0-0.0030%, and Ga: 0-0.0030%, with the balance being Fe and impurities; The plate thickness t is 0.30 mm or less, F1 defined by formula (1) is 10.0 or more, F2 defined by formula (2) is 8.5 or less, and F4 defined by formula (4) is the iron loss W at a frequency of 400 Hz and a magnetic flux density of 1.0 T. １０／４００ The stator core is as follows: F1 = 4Si + 3Al + 2Mn (1) F2 = 2Si + 3Al + Mn (2) F4 = 4 + 800 × t / (5 + 6Si + 5Al + 3Mn) (4) Here, the element symbols in formulas (1), (2) and (4) are substituted with the content of the corresponding element in mass%, and t is substituted with the plate thickness in mm.

11. A stator core according to claim 10, wherein the stator core material further includes a crimped portion and a flat portion which is a flat region, the crimped portion includes an inclined portion formed at an angle relative to the flat portion, and the thickness of the inclined portion is 85% or less of the thickness of the flat portion.

12. A stator core according to claim 11, wherein in a cross section including a central axis of the stator core material, a Vickers hardness H ２４ is 175 HV or more, and the Vickers hardness H ２２１ is the Vickers hardness H ２４ A stator core having a resistance of ±10HV or less.

13. A motor comprising: a rotor core according to any one of claims 7 to 9; and a stator core according to any one of claims 10 to 12.

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