Non-oriented electrical steel sheet, core, cold-rolled steel sheet, method for manufacturing non-oriented electrical steel sheet, and method for manufacturing cold-rolled steel sheet
A non-oriented electrical steel sheet has a predetermined chemical composition. The chemical composition satisfies (2×[Mn]+2.5×[Ni]+[Cu])−([Si]+2×[sol.Al]+4×[P])≥1.50%. In a case where Ahkl-uvw represents the area ratio of crystal grains in an {hkl}<uvw> orientation to the entire visual field when a plane at a depth of ½ of a sheet thickness from a surface parallel to a rolled surface is measured by SEM-EBSD, A411-011 is 15.0% or more, and the average grain size is 50 μm to 150 μm.
1 . A non-oriented electrical steel sheet comprising, as a chemical composition, by mass %:
C: 0.0100% or less;
Si: 1.50% to 4.00%;
sol.Al: 0.0001% to 1.00%;
S: 0.0100% or less;
N: 0.0100% or less;
one or more of Mn, Ni, and Cu: 2.5% to 5.0% in total;
Co: 0% to 1.0%;
Sn: 0% to 0.40%;
Sb: 0% to 0.40%;
P: 0% to 0.400%;
one or more of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0% to 0.010% in total; and
a remainder of Fe and impurities,
wherein the following Equation (1) is satisfied, where, by mass %, a Mn content is [Mn], a Ni content is [Ni], a Cu content is [Cu], a Si content is [Si], a sol.Al content is [sol.Al], and a P content is [P],
in a case where Ahkl-uvw represents an area ratio of crystal grains in an {hkl}<uvw> orientation to an entire visual field when a plane at a depth of ½ of a sheet thickness from a surface parallel to a rolled surface is measured by SEM-EBSD (Scanning Electron Microscope-Electron Back Scattering Diffraction), A411-011 is 15.0% or more, and
an average grain size is 50 μm to 150 μm,
(
2
×
[
Mn
]
+
2.5
×
[
Ni
]
+
[
Cu
]
)
-
(
[
Si
]
+
2
×
[
sol
.
Al
]
+
4
×
[
P
]
)
≥
1.5
%
.
(
1
)
2 . The non-oriented electrical steel sheet according to claim 1 ,
wherein when the surface is measured by the SEM-EBSD to create an ODF (Orientation Distribution Function)_at φ2=45°, the non-oriented electrical steel sheet has a maximum intensity at φ1=0° to 10° among φ1=0° to 90° and Φ=20°, and has a maximum intensity at Φ=5° to 35° among Φ1=0° and Φ=0° to 90°.
3 . The non-oriented electrical steel sheet according to claim 1 or 2 ,
wherein an area ratio of a specific orientation to the entire visual field when the plane at the depth of ½ of the sheet thickness from the surface parallel to the rolled surface is measured by the SEM-EBSD satisfies both the following Equations (2) and (3),
A
411
-
011
/
A
411
-
148
≥
1.1
(
2
)
A
411
-
011
/
A
100
-
011
≥
2.
.
(
3
)
4 . A core comprising the non-oriented electrical steel sheet according to claim 3 .
5 . A cold-rolled steel sheet which is used for manufacturing the non-oriented electrical steel sheet according to claim 3 , the cold-rolled steel sheet comprising, as a chemical composition, by mass %:
C: 0.0100% or less;
Si: 1.50% to 4.00%;
sol.Al: 0.0001% to 1.00%;
S: 0.0100% or less;
N: 0.0100% or less;
one or more of Mn, Ni, and Cu: 2.5% to 5.0% in total;
Co: 0% to 1.0%;
Sn: 0% to 0.40%;
Sb: 0% to 0.40%;
P: 0% to 0.400%;
one or more of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0% to 0.010% in total; and
a remainder of Fe and impurities,
wherein the following Equation (1) is satisfied, where, by mass %, a Mn content is [Mn], a Ni content is [Ni], a Cu content is [Cu], a Si content is [Si], a sol.Al content is [sol.Al], and a P content is [P], and
an area ratio A aα of crystal grains having a crystal orientation of an a-fiber to an entire visual field when a plane at a depth of ½ of a sheet thickness from a surface parallel to a rolled surface is measured by SEM-EBSD is 15.0% or more,
(
2
×
[
Mn
]
+
2.5
×
[
Ni
]
+
[
Cu
]
)
-
(
[
Si
]
+
2
×
[
sol
.
Al
]
+
4
×
[
P
]
)
≥
1.5
%
.
(
1
)
6 . A core comprising the non-oriented electrical steel sheet according to claim 1 or 2 .
7 . A cold-rolled steel sheet which is used for manufacturing the non-oriented electrical steel sheet according to claim 1 or 2 , the cold-rolled steel sheet comprising, as a chemical composition, by mass %:
C: 0.0100% or less;
Si: 1.50% to 4.00%;
sol.Al: 0.0001% to 1.00%;
S: 0.0100% or less;
N: 0.0100% or less;
one or more of Mn, Ni, and Cu: 2.5% to 5.0% in total;
Co: 0% to 1.0%;
Sn: 0% to 0.40%;
Sb: 0% to 0.40%;
P: 0% to 0.400%;
one or more of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0% to 0.010% in total; and
a remainder of Fe and impurities,
wherein the following Equation (1) is satisfied, where, by mass %, a Mn content is [Mn], a Ni content is [Ni], a Cu content is [Cu], a Si content is [Si], a sol. Al content is [sol.Al], and a P content is [P], and
an area ratio A aα of crystal grains having a crystal orientation of an a-fiber to an entire visual field when a plane at a depth of ½ of a sheet thickness from a surface parallel to a rolled surface is measured by SEM-EBSD is 15.0% or more,
(
2
×
[
Mn
]
+
2.5
×
[
Ni
]
+
[
Cu
]
)
-
(
[
Si
]
+
2
×
[
sol
.
Al
]
+
4
×
[
P
]
)
≥
1.5
%
.
(
1
)
8 . A method for manufacturing a non-oriented electrical steel sheet according to claim 1 , the method comprising:
a hot rolling step of performing hot rolling on a steel material so that a final pass of finish rolling is performed at an Ar3 temperature or higher to obtain a hot-rolled steel sheet, the steel material including, as a chemical composition, by mass%: C: 0.0100% or less, Si: 1.50% to 4.00%, sol.Al: 0.0001% to 1.00%, S: 0.0100% or less, N: 0.0100% or less, one or more of Mn, Ni, and Cu: 2.5% to 5.0% in total, Co: 0% to 1.0%, Sn: 0% to 0.40%, Sb: 0% to 0.40%, P: 0% to 0.400%, one or more of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0% to 0.010% in total, and a remainder of Fe and impurities, in which the following Equation ( 1 ) is satisfied, where, by mass%, a Mn content is [Mn], a Ni content is [Ni], a Cu content is [Cu], a Si content is [Si], a sol.Al content is [sol.Al], and a P content is [P];
a cooling step of cooling the hot-rolled steel sheet after the hot rolling step;
a cold rolling step of performing cold rolling on the hot-rolled steel sheet after the cooling step to obtain a cold-rolled steel sheet;
an intermediate annealing step of performing intermediate annealing on the cold-rolled steel sheet;
a skin pass rolling step of performing skin pass rolling on the cold-rolled steel sheet after the intermediate annealing step to obtain the non-oriented electrical steel sheet; and
a final annealing step of performing final annealing on the non-oriented electrical steel sheet after the skin pass rolling step at an annealing temperature of 750°C. or higher and an Ac1 temperature or lower and at an annealing time of 2 hours or longer,
wherein in the cooling step, the cooling is started after 0.10 seconds or longer have elapsed from the final pass of the finish rolling, a temperature is set to 300°C. or higher and an Ar1 temperature or lower for transformation after 3 seconds, and
a rolling reduction in the skin pass rolling step is 5% to 20%.
9 . The method for manufacturing a non-oriented electrical steel sheet according to claim 8 , wherein in the cooling step, an average grain size of the hot-rolled steel sheet after the cooling step is 3 to 10 μm.
10 . The method for manufacturing a non-oriented electrical steel sheet according to claim 9 ,
wherein a rolling reduction in the cold rolling step is 75% to 95%.
11 . The method for manufacturing a non-oriented electrical steel sheet according to claim 10 ,
wherein in the intermediate annealing step, an annealing temperature is set to the Ac1 temperature or lower.
12 . The method for manufacturing a non-oriented electrical steel sheet according to claim 9 ,
wherein in the intermediate annealing step, an annealing temperature is set to the Ac1 temperature or lower.
13 . The method for manufacturing a non-oriented electrical steel sheet according to claim 8 ,
wherein a rolling reduction in the cold rolling step is 75% to 95%.
14 . The method for manufacturing a non-oriented electrical steel sheet according to claim 13 ,
wherein in the intermediate annealing step, an annealing temperature is set to the Ac1 temperature or lower.
15 . The method for manufacturing a non-oriented electrical steel sheet according to claim 8 ,
wherein in the intermediate annealing step, an annealing temperature is set to the Ac1 temperature or lower.