The present invention relates to an
electrical steel sheet.
BACKGROUND ART
[0002] In recent years, products with less
consumption energy have been developed in the fields
of vehicles, home electric appliances, and so on due
to a need to reduce global greenhouse gas. In the
field of vehicles, for example, there are a hybrid
drive vehicle with a combination of a gasoline engine
and a motor and a fuel-efficient vehicle such as a
motor drive electric vehicle. Further, in the field
of home electric appliances, there are a highefficiency
air conditioner, a refrigerator, and so
on, each of which has less annual electrical usage.
The technique common to these is a motor, and
increasing efficiency of a motor is an important
technique.
[0003] Then, in recent years, a divided iron core
advantageous in terms of winding design and yield has
been often employed for a stator of a motor.
Normally, the divided iron core is often fixed to a
case by shrink fitting, and when a compressive stress
acts on an electrical steel sheet by shrink fitting,
magnetic properties of the electrical steel sheet
decrease. Conventionally, studies for suppressing
such a decrease in magnetic properties have been
conducted.
[0004] However, a conventional electrical steel
sheet is likely to be affected by a compressive
stress, and therefore not able to exhibit excellent
magnetic properties when used for a divided iron
core, for example.
CITATION LIST
PATENT LITERATURE
[0005] Patent Literature 1: Japanese Laid-open
Patent Publication No. 2008-189976
Patent Literature 2: Japanese Laid-open Patent
Publication No. 2000-104144
Patent Literature 3: Japanese Laid-open Patent
Publication No. 2000-160256
Patent Literature 4: Japanese Laid-open Patent
Publication No. 2000-160250
Patent Literature 5: Japanese Laid-open Patent
Publication No. 11-236618
Patent Literature 6: Japanese Laid-open Patent
Publication No. 2014-77199
Patent Literature 7: Japanese Laid-open Patent
Publication No. 2012-36457
Patent Literature 8: Japanese Laid-open Patent
Publication No. 2012-36454
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0006] An object of the present invention is to
provide an electrical steel sheet capable of
exhibiting excellent magnetic properties even when a
compressive stress acts thereon.
SOLUTION TO PROBLEM
[ 0 0 0 7 1 The present inventors conducted earnest
studi~es in order to clarify the reason why excellent
magnetic properties cannot be obtained when a
conventional electrical steel sheet is used for a
divided iron core. As a result, it was revealed that
the relationship between the direction in which a
compressive stress acts and crystal orientations of
an el~ectrical steel sheet is important.
[ 0 0 0 8 1 The compressive stress to act on the
electrical steel sheet will be explained. A drive
motor of a hybrid vehicle and a compressor motor of
an air conditioner are multipolar, and therefore,
normally the direction of a magnetic flux passing
through a teeth part of a stator corresponds to the
rolling direction (to be sometimes referred to as "L
direction" hereinafter) of the electrical steel
sheet, and the direction of a magnetic flux passing
through a yoke part corresponds to the direction
perpendicular to the rolling direction and the sheet
thickness direction (to be sometimes referred to as
"C direction" hereinafter). When the divided iron
core is fixed to a case or the like by shrink
fitting, a compressive stress in the C direction acts
on the electrical steel sheet of the yoke part, but
no stress acts on the electrical steel sheet of the
teeth part. Accordingly, the electrical steel sheet
used for the divided iron core is desired to be able
to exhibit excellent magnetic properties in Llie C
direction under the compressive stress acting in the
C direction while exhibiting excellent magnetic
properties in the L direction under no stress.
[00091 The preseIlL inventors further conducted
earnest studies in order to clarify the constitution
for exhibiting such magnetic properties. As a
result, it was revealed that crystal grains in the
Goss orientation are not likely to be affected by the
compressive stress in the C direction and the
decrease in magnetic properties in the C direction is
not easily caused even if the compressive stress in
the C direction is applied, and crystal grains in the
Cube orientation are likely to be affected by the
compressive stress in the C direction and the
decrease in magnetic properties in the C direction is
easily caused when the compressive stress in the C
direction is applied. Then, it was revealed that
excellent magnetic properties can be obtained by
appropriately controlling the accumulation degree of
the (001)[100] orientation and the accumulation
degree of the (011) [loo] orientation.
[0010] As a result that the present inventors
further conducted earnest studies repeatedly based on
such findings, they have reached the following
various aspects of the invention.
[0011] (1) An electrical steel sheet includes:
a chemical composition represented by, in mass%:
C: 0.010% or less;
Si: 1.30% to 3.50%;
Al: 0.0000% to 1.6000%;
Mn: 0.01% to 3.00%;
S : 0.0100% or less;
N: 0.010% or less;
P: 0.000% to 0.150%;
Sn: 0.000% to 0.150%;
Sb: 0.000% to 0.150%;
Cr: 0.000% to 1.000%;
Cu: 0.000% to 1.000%;
Ni: 0.000% to 1.000%;
Ti: 0.010% or less;
V: 0.010% or less;
~ b :0. 010% or less; and
balance: Fe and impurities;
a crystal grain diameter of 20 pm to 300 pm; and
a texture satisfying Expression 1, Expression 2,
and Expression 3 when the accumulation degree of the
(001)[ I001 orientation is represented as ICubaen d the
accumulation degree of the (011)[100] orientation is
represented as 1 ~ ~ ~ ~ .
IGoss+ ICuhe2 10.5 . . .Expression 1
I G s s / I c u>e 0.50 . . .Expression 2
Icube 2 2. 5 . . . Expression 3
[0012] (2) The electrical steel sheet according to
(I), wherein the texture satisfies Expression 4,
Expression 5, and Expression 6
iGos+s Icube 2 10.7 . . .Expression 4
I G ~ ~ 2~ 0/.5I2 c .~ . . E~xp~res sion 5
ICuh2e 2.7 . . .E xpression 6
[0013] (3) The electrical steel sheet according to
(1) or (Z), further includes:
magnetic properties satisfying Expression 7 and
Expression 8 when a saturation magnetic flux density
is represented as Bs, a magnetic flux density in the
rolling direction at being magnetized by a
magnetizing force of 5000 A/m is represented as B50L,
and a magnetic flux density in the direction
perpendicular to the rolling direction and the sheet
thickness direction (sheet width direction) at being
magnetized by a magnetizing force of 5000 A/m is
represented as B50C.
B50C/Bs 2 0.790 . . . Expression 7
(B50L - B5OC) /Bs > 0.070 . . .Expression 8
[0014] (4) The electrical steel sheet according to
( 3 ) , wherein the magnetic properties satisfy
Expression 9.
(B50L - B50C) /Bs 2 0.075 . . .Expression 9
[0015] (5) The electrical steel sheet according to
(3) or (4), wherein the magnetic properties satisfy
Expression 10.
B50C/Bs 0.825 . . . Expression 10
[0016] (6) The electrical steel sheet according to
any one of (1) to (5), wherein in the chemical
composition,
P: 0.001% to 0.150%,
Sn: 0.001% to 0.150%, or
Sb: 0.001% to 0.150%, or any combination thereof
is satisfied.
[0017] (7) The electrical steel sheet according to
any one of (I) to (6), wherein in the chemical
composition,
Cr: 0.005% to 1.000%,
Cu: 0.005% to 1.000%,
Ni: 0.005% to 1.000%, or any combination thereof
is satisfied.
[0018] (8) The electrical steel sheet according to
any one of (1) to ( 7 ) , wherein a thickness thereof is
0.10 mm to 0.50 mm.
ADVANTAGEOUS EFFECTS OF INVENTION
[0019] According to the present invention, an
appropriate texture is included, thereby making it
possible to exhibit excellent magnetic properties
even when a compressive stress acts.
BRIEF DESCRIPTION OF DRAWINGS
[0020] [Fig. 11 Fig. 1 is a view illustrating a
relationship between an accumulation degree and a
core loss W15/400L obtained in a first test.
[Fig. 21 Fig. 2 is a view illustrating a
relationship between the accumulation degree and a
core loss W15/400C obtained in the first test.
[Fig. 31 Fig. 3 is a view illustrating a
distribution of the accumulation degree in the first
test.
[Fig. 41 Fig. 4 is a view illustrating a
distribution of a magnetic flux density in the first
test.
D E S C R I P T I O N OF EMBODIMENTS
[0021] Hereinafter, embodiments of the present
invention will be described in detail with reference
to the attached drawings.
100221 First, a texture of an electrical steel sheet
according to the embodiment of the present invention
will be described. The electrical steel sheet
according to the embodiment of the present invention
has a texture satisfying Expression 1, Expression 2,
and Expression 3 when the accumulation degree of the
(001)[100] orientation (to be sometimes referred to
as "Cube orientation" hereinafter) is represented as
ICubaen d the accumulation degree of the (011)[ I001
orientation (to be sometimes referred to as "Goss
orientation" hereinafter) is represented as 1 ~ T~he ~ ~ .
accumulation degree of a certain orientation means
the ratio of an intensity in the orientation to a
random intensity (random ratio), and is an index used
normally when a texture is indicated.
I G+ ~I c u h e~ ~10. 5 . . .Expression 1
IGosS/IC3u> b0e. 50 . . .Expression 2
I c u b e > 2.5 . . . Expression 3
[0023] Crystal grains in the Goss orientation
contribute to an improvement in magnetic properties
particularly in the L direction. Crystal grains in
the Cube orientation contribute to improvements in
magnetic properties in the L direction and magnetic
properties in the C direction. As described above,
the present inventors revealed that the crystal
grains in the Goss orientation are not likely to be
affected by the compressive stress in the C direction
and the decrease in magnetic properties in the C
direction is not easily caused even when the
compressive stress in the C direction is applied, and
the crystal grains in the Cube orientation are likely
to be affected by the compressive stress in the C
direction and the decrease in magnetic properties in
the C direction is caused easily when the compressive
stress in the C direction is applied.
[00241 When the value of "IGoss+ I C u b e r ' is less than
10.5, sufficient magnetic properties in the L
direction cannot be obtained under no stress. Thus,
Expression 1 needs to be satisfied. For the purpose
of obtaining more excellent magnetic properties in
the L direction under no stress, the value of "IGos+s
ICubeits' preferably 10.7 or more and more preferably
11.0 or more.
LO0251 When the value of " I G o s s / I C u b e " is less than
0.50, sufficient magnetic properties in the C
direction cannot be obtained when the compressive
stress in the C direction is applied. Thus,
Expression 2 needs to be satisfied. For the purpose
of obtaining more excellent magnetic properties in
the C direction under the compressive stress in the C
direction, the value of " I G ~ ~ i~s /prIef~er~abl~y ~0."52
or more and more preferably 0.55 or more. The
relationship between the value of "IGOSs/ICUanbde "t he
magnetic properties in the C direction under the
compr~essive stress in the C direction is not clear,
but is thought as follows. In general, when the
compressive stress acts in the <100> direction, the
magnetic properties are likely to deteriorate rather
than the case when the compressive stress acts
paral.le1 to the <110> direction. The C direction of
crystal grains in the (001) [loo] orientation (Cube
orientation) corresponds to the [010] direction, and
the C direction of crystal grains in the (011)[100]
orientation (Goss orientation) corresponds to the
[Ol-11 direction. Thus, it is thought that as the
value of "IG,,,/Ic,~," is lower, namely as the ratio of
crystal grains in the Cube orientation is higher, the
ratio of the crystal grains in the direction
parallel to the C direction is higher and the
magnetic properties of the electrical steel sheet are
more likely to decrease by the compressive stress in
the C direction.
[0026] Also when the value of " I C U b e " is less than
2.5, sufficient magnetic properties in the C
direction cannot be obtained when the compressive
stress in the C direction is applied. Thus,
Expression 3 needs to be satisfied. For the purpose
of obtaining more excellent magnetic properties in
the C direction under the compressive stress in the C
direction, the value of "Icubei"s preferably 2 . 7 or
more and more preferably 3.0 or more.
[0027] When Expression 3 is not satisfied even
though Expression 2 is satisfied, although the
magnetic properties in the C direction are not likely
to decrease by the compressive stress in the C
direction, sufficient magnetic properties in the C
direction cannot be obtained under no stress, and
therefore the magnetic properties in Lhe C direction
under the compressive stress in the C direction are
not sufficient. When Expression 2 and Expression 3
are not satisfied, sufficient magnetic properties in
the C direction cannot be obtained under no stress
and the magnetic properties in the C direction
decrease by the compressive stress in the C
direction, and therefore the magnetic properties in
the C direction under the compressive stress in the C
direction are not sufficient. When Expression 2 is
not satisfied even though Expression 3 is satisfied,
although sufficient magnetic properties in the C
direction can be obtained under no stress, the
magnetic properties in the C direction decrease by
the compressive stress in the C direction, and
therefore the magnetic properties in the C direction
under the compressive stress in the C direction are
not sufficient. When Expression 2 and Expression 3
are satisfied, sufficient magnetic properties in the
C direction can be obtained under no stress and the
magnetic properties in the C direction are not likely
to decrease by the compressive stress in the C
direction, and therefore excellent magnetic
properties in the C direction can be obtained under
the compressive stress in the C direction.
LO0281 The accumulation degree I,,,, and the
accumulation degree Icube can be measured in the
following manner. First, (110), (200), and (211)
pole figures of an electrical steel sheet being a
measuring object are measured by the X-ray
diffraction Schultz method. At this time, measuring
positions are the position where the depth of the
electrical steel sheet from the surface is 1/4 of the
thickness (to be sometimes referred to as "1/4
position" hereinafter) and the position where the
depth of the electrical steel sheet from the surface
is 1/2 of the thickness (to be sometimes referred to
as "1/2 position" hereinafter). Next, a threedimensional
orientation analysis is performed by the
series expansion method using the pole figures. The
average value of three-dimensional orientation
distribution densities at the 1/4 position and the
1/2 position is calculated with respect to each of
the (001)[1001 orientation (Cube orientation) and the
(011) [I001 orientation (Goss orientation) obtained by
the analysis. The two types of values obtained in
this manner can be the accumulation degree IGoss and
the accumulation degree Icube respectively.
[0029] As described above, the texture preferably
satisfies Expression 4, Expression 5, and Expression
6.
+ ICube 10.7 . . .Expression 4
I G ~ ~ ~2/ 0I.5c2 ~ .~ . .~Ex pression 5
Icube 2 2. 7 ... Expression 6
[0030] Next, magnetic properties of the electrical
steel sheet according to the embodiment of the
present invention will be described. The electrical
steel sheet according to the embodiment of the
present invention preferably has magnetic properties
satisfying Expression 7 and Expression 8 when a
saturation magnetic flux density is represented as
Bs, a magnetic flux density in the rolling direction
at being magnetized by a magnetizing force of 5000
A/m is represented as BSOL, and a magnetic flux
density in the direction perpendicular to the rolling
direction and the sheet thickness direction (sheet
width direction) at being magnetized by a magnetizing
force of 5000 A/m is represented as B50C.
B50C/Bs 1 0.790 ... Expression 7
(B50L - B50C) /Bs 0.070 . . .Expression 8
[0031] When the value of "B50C/BsW is less than
0.790, sufficient magnetic properties in the C
direction sometimes may not be obtained under the
compressive stress. Thus, Expression 7 is preferably
satisfied. For the purpose of obtaining more
excellent magnetic properties in the C direction
under the compressive stress in the C direction, the
value of "B50C/Bsn is more preferably 0.795 or more
and further preferably 0.800 or more. On the other
hand, when "B50C/Bsn is too high, the magnetic
properties may become likely to deteriorate by the
compressive stress, so that the value of "B50C/BsV is
preferably 0.825 or less, further preferably 0.820 or
less, and furthermore preferably 0.815 or less.
[00321 When the value of " (B50L - BSOC) /Bs" is less
than 0.070, sufficient magnetic properties in the C
direction sometimes may not be obtained under the
compressive stress. Thus, Expression 8 is preferably
satisfied. The magnetic properties may become likely
to deteriorate by the compressive stress, so that the
value of "(B50L - B50C)/BsV is more preferably 0.075
or more and further preferably 0.080 or more.
[0033] As described above, the magnetic properties
preferably satisfy Expression 9 or Expression 10 or
the both.
(B50L - B50C) /Bs 1 0.075 . . .Expression 9
B50C/Bs 0.825 ... Expression 10
[0034] Next, a chemical composition of the
electrical steel sheet according to the embodiment of
the present invention and a slab used for manufacture
of the electrical steel sheet will be described. The
electrical steel sheet according to the embodiment of
the present invention is manufactured by hot rolling
of slab, hot-rolled sheet annealing, first cold
rolling, intermediate annealing, second cold rolling,
finish annealing, and the like, of which details will
be described later. Thus, not only properties of the
electrical steel sheet but also these processes are
considered in the chemical composition of the
electrical steel sheet and the slab. In the
following description, " % " being a unit of a content
of each element contained in the electrical steel
sheet means "mass%" unless otherwise specified. The
elect.rical steel sheet according to the embodiment
includes a chemical composition represented by C:
0.010% or less, Si: 1.30% to 3.50%, Al: 0.0000% to
1.6000%, Mn: 0.01% to 3.00%, S: 0.0100% or less, N:
0.010% or less, P: 0.000% to 0.150%, Sn: 0.000% to
0.150%, Sb: 0.000% to 0.150%, Cr: 0.000% to 1.000%,
Cu: 0.000% to 1.000%, Ni: 0.000% to 1.000%, Ti:
0.010% or less, V: 0.010% or less, Nb: 0.010% or
less, and balance: Fe and impurities. Examples of
the impurities include ones contained in raw
materials such as ore and scrap, and ones mixed in a
manufacturing process.
[00351 (Si: 1.30% to 3.50%)
Si is an element effective for increasing
specific resistance to reduce a core loss. When the
content of Si is 1.30% or more, it is possible to
more securely obtain the specific resistance
improving effect. Thus, the content of Si is 1.30%
or more. The content of Si is preferably 1.60% or
more and more preferably 1.90% or more. On the other
hand, when the content of Si is greater than 3.50%, a
desired texture cannot be obtained and a desired
magnetic flux density cannot be obtained. Thus, the
content of Si is 3.50% or less. The content of Si is
preferably 3.30% or less and more preferably 3.10% or
less. The reason why a desired texture cannot be
obtained when the content of Si is greater than 3.50%
is thought that a change in deformation behavior in
cold rolling is caused due to an increase in the
content of Si.
[0036] (Al: 0.0000% to 1.6000%)
A1 is an element to decrease a saturation
magnetic flux density. When the content of A1 is
greater than 1.6000%, a desired texture cannot be
obtained and a desired magnetic flux density cannot
be obtained. Thus, the content of A1 is 1.6000% or
less. The content of A1 is preferably 1.4000% or
less, more preferably 1.2000% or less, and further
preferably 0.8000% or less. The reason why a desired
texture cannot be obtained when the content of A1 is
greater than 1.6000% is thought that a change in
deformation behavior in cold rolling is caused due to
an increase in the content of Al. The lower limit of
the content of A1 .is not limited in particular. A1
has an effect of increasing specific resistance to
reduce a core loss, and for the purpose of obtaining
this effect, the content of A1 is preferably 0.0001%
or more and more preferably 0.0003% or more.
[0037] (Mn: 0.01% to 3.00%)
Mn is an element effective for increasing
specific resistance to reduce a core loss. When the
content of Mn is 0.01% or more, it is possible to
more securely obtain such a specific resistance
improving effect. Thus, the content of Mn is 0.01%
or more. The content of Mn is preferably 0.03% or
more and more preferably 0.05% or more. On the other
hand, when Mn is contained excessively, the magnetic
flux density decreases. Such a phenomenon is
significant when the content of Mn is greater than
3.00%. Thus, the content of Mn is 3.00% or less.
The content of Mn is preferably 2.70% or less, more
preferably 2.50% or less, and further preferably
2.40% or less.
[00381 (C: 0.010% or less)
C is not an essential element but is contained in
a steel as an impurity, for example. C is an element
to deteriorate magnetic properties by magnetic aging.
Thus, the lower the content of C is, the better it
is. Such deterioration of magnetic properties is
significant when the content of C is greater than
0.010%. For this reason, the content of C is 0.010%
or less. The content of C is preferably 0.008% or
less and more preferably 0.005% or less.
[0039] (S: 0.0100% or less)
S is not an essential element but is contained in
a steel as an impurity, for example. S bonds to Mn
in a steel to form fine MnS to inhibit grain growth
during finish annealing and deteriorate magnetic
properties. Thus, the lower the content of S is, the
better it is. Such deterioration of magnetic
properties is significant when the content of S is
greater than 0.0100%. For this reason, the content
of S is 0.0100% or less. The content of S is
preferably 0.0080% or less and more preferably
0.0050% or less. S contributes to an improvement in
magnetic flux density. For the purpose of obtaining
this effect, 0.0005% or more of S may also be
contained. The reason why S contributes to an
improvement in magnetic flux density is thought that
the grain growth in an orientation disadvantageous to
the magnetic properties is inhibited by S.
[0040] (N: 0.010% or less)
N is not an essential element but is contained in
a steel as an impurity, for example. N bonds to A1
in a steel to form fine A1N to inhibit grain growth
during finish annealing and deteriorate magnetic
properties. Thus, the lower the content of N is, the
better it is. Such deterioration of magnetic
properties is significant when the content of N is
greater than 0.010%. For this reason, the content of
N is 0.010% or less. The content of N is preferably
0.008% or less and more preferably 0.005% or less.
[0041] P, Sn, Sb, Cr, Cu, and Ni are not essential
elements but are arbitrary elements, which may be
contained appropriately in the electrical steel sheet
up to a specific amount as a limit.
[0042] (P: 0.000% to 0.150%, Sn: 0.000% to 0.150%,
Sb: 0.000% to 0.150%)
P, Sn, and Sb each have an effect to improve the
texture of the electrical steel sheet to improve
magnetic properties. Thus, P, Sn, or Sb, or any
combination thereof may also be contained. For the
purpose of sufficiently obtaining this effect, P:
0.001% or more, Sn: 0.001% or more, or Sb: 0.001% or
more, or any combination thereof is preferable, and
P: 0.003% or more, Sn: 0.003% or more, or Sb: 0.003%
or more, or any combination thereof is more
preferable. However, excessive P, Sn, and Sb may
cause segregation in a crystal grain diameter to
decrease ductility of the steel sheet, resulting in
difficulty in cold rolling. Such a decrease in
ductility is significant in the case of P: greater
than 0.150%, Sn: greater than 0.150%, or Sb: greater
than 0.150%, or any combination thereof. For this
reason, P: 0.150% or less, Sn: 0.150% or less, and
Sb: 0.150% or less are set. P: 0.100% or less, Sn:
0.100% or less, or Sb: 0.100% or less, or any
combination thereof is preferable, and P: 0.050% or
less, Sn: 0.050% or less, or Sb: 0.050% or less, or
any combination thereof is more preferable. That is,
P: 0.001% to 0.150%, Sn: 0.001% to 0.150%, or Sb:
0.001% to 0.150%, or any combination thereof is
preferably satisfied.
[0043] (Cr: 0.000% to 1.000%, Cu: 0.000% to 1.000%,
Ni: 0.000% to 1.000%)
Cr, Cu, and Ni are elements effective for
increasing specific resistance to reduce a core loss.
Thus, Cr, Cu, or Ni, or any combination thereof may
also be contained. For the purpose of sufficiently
obtaining this effect, Cr: 0.005% or more, Cu: 0.005%
or more, or Ni: 0.005% or more, or any combination
thereof is preferable, and Cr: 0.010% or more, Cu:
0.010% or more, or Ni: 0.010% or more, or any
combination thereof is more preferable. However,
excessive Cr, Cu, and Ni may deteriorate the magnetic
flux density. Such deterioration of magnetic flux
density is significant in the case of Cr: greater
than 1.000%, Cu: greater than 1.000%, or Ni: greater
than 1.000%, or any combination thereof. For this
reason, Cr: 1.000% or less, Cu: 1.000% or less, and
Ni: 1.000% or less are set. Cr: 0.500% or less, Cu:
0.500% or less, or Ni: 0.500% or less, or any
combination thereof is preferable, and Cr: 0.300% or
less, Cu: 0.300% or less, or Ni: 0.300% or less, or
any combination thereof is more preferable. That is,
Cr: 0.005% to 1.000%, Cu: 0.005% to 1.000%, or Ni:
0.005% to 1.000%, or any combination thereof is
preferably satisfied.
[0044] (Ti: 0.010% or less, V: 0.010% or less, Nb:
0.010% or less)
Ti, V, and Nb are not essential elements but are
contained in a steel as an impurity, for example.
Ti, V, and Nb bond to C, N, Mn, or other element to
form inclusions to inhibit growth of crystal grains
during annealing and deteriorate magnetic properties
Thus, the lower the content of Ti, the content of V,
and the content of Nb are, the better it is. Such
deterioration of magnetic properties is significant
in the case of Ti: greater than 0.010%, V: greater
than 0.010%, or Nb: greater than 0.010%, or any
combination thereof. For this reason, Ti: 0.010% or
less, V: 0.010% or less, and Nb: 0.010% or less are
set. Ti: 0.007% or less, V: 0.007% or less, or Nb:
0.007% or less, or any combination thereof is
preferable, and Ti: 0.004% or less, V: 0.004% or
less, or Nb: 0.004% or less, or any combination
thereof is more preferable.
100451 Next, an average crystal grain diameter of
the electrical steel sheet according to the
embodiment of the present invention will be
described. Even when the average crystal grain
diameter is too large or too small, the core loss
deteriorates. Such deterioration of core loss is
significant when the average crystal grain diameter
is less than 20 pm or greater than 300 pm. Thus, the
average crystal grain diameter is 20 pm to 300 pm.
The lower limit of the average crystal grain diameter
is preferably 30 pm and further preferably 40 pm.
The upper limit of the average crystal grain diameter
is preferably 250 pm and further preferably 200 pm.
LO0461 As the average crystal grain diameter, the
average value of crystal grain diameters measured in
the sheet thickness direction and the rolling
direction by the intercept method in a vertical
section structure photograph parallel to the sheet
thickness direction and the rolling direction can be
used. As the vertical section structure photograph,
an optical micrograph can be used, and, for example,
a photograph taken at 50-fold magnification can be
used.
100471 Next, the thickness of the electrical steel
sheet according to the embodiment of the present
invention will be described. When the electrical
steel sheet is too thin, productivity may
deteriorate, resulting in that it is not easy to
manufacture an electrical steel sheet having a
thickness of less than 0.10 mm with high
productivity. Thus, the sheet thickness is
preferably 0.10 mm or more. The sheet thickness of
the electrical steel sheet is more preferably 0.15 mm
or more and further preferably 0.20 mm or more. On
the other hand, when the electrical steel sheet is
too thick, the core loss may deteriorate. Such
deterioration of core loss is significant when the
sheet thickness is greater than 0.50 mm. For this
reason, the sheet thickness is preferably 0.50 mm or
less. The sheet thickness of the electrical steel
sheet is more preferably 0.35 mm or less and further
preferably 0.30 mm or less.
[00481 Next, a preferred method of manufacturing the
electrical steel sheet according to the embodiment
will be described. In the manufacturing method, hot
rolling of slab, hot-rolled sheet annealing, first
cold rolling, intermediate annealing, second cold
rolling, and finish annealing are performed.
[00491 In the hot rolling, for example, a slab
having the above-described chemical composition is
charged into a heating furnace and is subjected to
hot rolling. When a slab temperature is high, it is
also possible to start hot rolling without charging
into a heating furnace. Various conditions of the
hot rolling are not limited in particular. The slab
can be obtained by continuous casting of a steel, or
obtained by bloom rolling of a steel ingot, for
example.
[00501 After the hot rolling, annealing of a hotrolled
steel sheet obtained by the hot rolling (hotrolled
sheet annealing) is performed. The hot-rolled
sheet annealing may also be performed using a box
furnace, and continuous annealing may also be
performed as the hot-rolled sheet annealing.
Hereinafter, annealing using a box furnace is
sometimes referred to as box annealing. When the
temperature of hot-rolled sheet annealing is too low
and when the time for hot-rolled sheet annealing is
too short, it may not be possible to sufficiently
coarsen crystal grains, resulting in that desired
magnetic properties sometimes may not be obtained.
On the other hand, when the temperature of hot-rolled
sheet annealing is too high and when the time for
hot-rolled sheet annealing is too long, manufacturing
costs may increase. When the box annealing is
performed, for example, the hot-rolled steel sheet is
preferably held for 1 hour to 200 hours at a
temperature zone of 700°C to llOO°C. The holding
temperature when performing the box annealing is more
preferably 730°C or more and further preferably 750°C
or more. The holding temperature when performing the
box annealing is more preferably 1050°C or less and
further preferably 1000°C or less. The holding time
- 23 -
when performing the box annealing is more preferably
2 hours or more and further preferably 3 hours or
more. The holding time when performing the box
annealing is more preferably 1 5 0 hours or less and
further preferably 1 0 0 hours or less. In the case of
performing the continuous annealing, for example, the
hot-rolled steel sheet is preferably passed through a
temperature zone of 750°C to 1250°C for a time period
of 1 second to 600 seconds. The holding temperature
when performing the continuous annealing is more
preferably 780°C or more and further preferably 80OoC
or more. The holding temperature when performing the
continuous annealing is more preferably 1220°C or less
and further preferably 1200°C or less. The holding
time when performing the continuous annealing is more
preferably 3 seconds or more and further preferably 5
seconds or more. The holding time when performing
the continuous annealing is more preferably 500
seconds or less and further preferably 400 seconds or
less. The average crystal grain diameter of an
annealed steel sheet obtained by the hot-rolled sheet
annealing is preferably 20 pm or more, more
preferably 35 pm or more, and further preferably 40
pm or more.
[00511 After the hot-rolled sheet annealing, cold
rolling (first cold rolling) of the annealed steel
sheet is performed. A cold rolling ratio of the
first cold rolling(to be sometimes referred to as
"first cold rolling ratio" hereinafter) is preferably
40% to 85%. When the first cold rolling ~ d L i u is
less than 40% or greater than 85%, a desired texture
may not be obtained and desired magnetic flux density
and core loss cannot be obtained. The first cold
rolling ratio is more pr-eferdhly 45% or more and
further preferably 50% or more. The first cold
rolling ratio is more preferably 80% or less and
further preferably 75% or less.
LO0521 After the first cold rolling, annealing
(intermediate annealing) of a cold-rolled steel sheet
obtained by the first cold rolling (to be sometimes
referred to as "intermediate cold-rolled steel sheet"
hereinafter) is performed. As the intermediate
annealing, box annealing may be performed, and
continuous annealing may also be performed as the
intermediate annealing. When the temperature of
intermediate annealing is too low and when the time
for intermediate annealing is too short, it may not
be possible to sufficiently coarsen crystal grains,
resulting in that desired magnetic properties
sometimes may not be obtained. On the other hand,
when the temperature of intermediate annealing is too
high and when the time for intermediate annealing is
too long, manufacturing costs may increase. When
performing the box annealing, for example, the coldrolled
steel sheet is preferably held for 1 hour to
200 hours at a temperature zone of 850°C to llOO°C.
The holding temperature when performing the box
annealing is more preferably 880°C or more and further
preferably 900°C or more. The holding tempeidLure
when performing the box annealing is more preferably
1050°C or less and further preferably 1000°C or less.
The holding time when performing the box annealing is
more preferably 2 hours or more and further
preferably 3 hours or more. The holding time when
performing the box annealing is more preferably 150
hours or less and further preferably 100 hours or
less. In the case of performing the continuous
annealing, for example, the hot-rolled steel sheet is
preferably passed through a temperature zone of 1050°C
to 1250°C for a time period of 1 second to 600
seconds. The holding temperature when performing the
continuous annealing is more preferably 10BO°C or more
and further preferably lllO°C or more. The holding
temperature when performing the continuous annealing
is more preferably 1220°C or less and further
preferably 1200°C or less. The holding time when
performing the continuous annealing is more
preferably 2 seconds or more and further preferably 3
seconds or more. The holding time when performing
the continuous annealing is more preferably 500
seconds or less and further preferably 400 seconds or
less. The average crystal grain diameter of an
intermediate annealed steel sheet obtained by the
intermediate annealing is preferably 140 pm or more,
more preferably 170 pm or more, and further
preferably 200 pm or more. As the intermediate
annealing, the box annealing is more preferable than
the continuous annealing.
[0053] After the intermediate annealing, cold
rolling (second cold rolling) of the intermediate
annealed steel sheet obtained by the intermediate
annealing is performed. A cold rolling ratio of the
second cold rolling (to be sometimes referred to as
"second cold rolling ratio" hereinafter) is
preferably 45% to 85%. When the second cold rolling
ratio is less than 45% or greater than 85%, a desired
texture may not be obtained and desired magnetic flux
density and core loss cannot be obtained. The second
cold rolling ratio is more preferably 50% or more and
further preferably 55% or more. The second cold
rolling ratio is more preferably 80% or less and
further preferably 75% or less.
[0054] After the second cold rolling, annealing
(finish annealing) of a cold-rolled steel sheet
obtained by the second cold rolling is performed.
When the temperature of finish annealing is too low
and when the time for finish annealing is too short,
the average crystal grain diameter of 20 pm or more
may not be obtained, resulting in that desired
magnetic properties sometimes may not be obtained.
On the other hand, in order to perform the finish
annealing at a temperature greater than 1250°C, a
special facility is needed, which may be
disadvantageous economically. When the time for
finish temperature is greater than 600 hours,
productivity may be low and it may be disadvantageous
economically. The temperature of finish annealing is
preferably 700°C to 1250°C, and the time for finish
annealing is preferably 1 second to 600 seconds. The
temperature of finish annealing is more preferably
750°C or more. The temperature of finish annealing is
more preferably 1200°C or less. The time for finish
annealing is more preferably 3 seconds or more. The
time for finish annealing is more preferably 500
seconds or less.
[0055] After the finish annealing, an insulating
coating film may also be formed on the surface of the
electrical steel sheet. As the insulating coating
film, one made of only organic components, one made
of only inorganic components, or one made of organicinorganic
compounds may also be formed. From a
viewpoint of reducing environmental loads, an
insulating coating film not containing chromium may
also be formed. Insulating coating that exhibits
adhesive ability by heating and pressurizing may also
be performed as coating. As a coating material that
exhibits adhesive ability, for example, an acrylic
resin, a phenol resin, an epoxy resin, a melamine
resin, or the like can be used.
[0056] Such an electrical steel sheet according to
the embodiment is suitable for an iron core of a
high-efficiency motor, particularly for a stator iron
core of a high-efficiency divided iron core type
motor. As the high-efficiency motor, for example,
compressor motors of an air conditioner, a
refrigerator, and so on, drive motors of an electric
vehicle, a hybrid vehicle, and so on, and a motor of
a power generator are exemplified.
[(I0571 In the foregoing, the preferred embodiment of
the present invention has been described in detail,
but, the present invention is not limited to such an
example. It is apparent that a person having common
knowledge in the technical field to which the present
invention belongs is able to devise various variation
or modification examples within the range of
technical ideas described in the claims, and it
should be understood that such examples belong to the
technical scope of the present invention as a matter
of course.
EXAMPLE
[0058] Next, the electrical steel sheet according to
the embodiment of the present invention will be
concretely described while giving examples. Examples
to be given below are just merely one example of the
electrical steel sheet according to the embodiment of
the present invention, and the electrical steel sheet
according to the present invention is not limited to
the following examples.
[0059] (First Test)
In the first test, the relationship between the
texture and the magnetic properties was examined.
First, a plurality of slabs each containing, in
mass%, C: 0.002%, Si: 2.10%, Al: 0.0050%, Mn: 0.20%,
S: 0.002%, N: 0.002%, P: 0.012%, Sn: 0.002%, Sb:
0.001%, Cr: 0.01%, Cu: 0.02%, Ni: 0.01%, Ti: 0.002%,
V: 0.002%, and Nb: 0.003%, and balance being composed
Fe and impurities were produced. Some of the slabs
were subjected to hot rolling, and thereby hot-rolled
steel sheets each having a sheet thickness of 2.5 mm
were obtained, and then box annealing for holding at
800°C for 10 hours, or continuous annealing for
holding at 1000°C for 30 seconds was performed as hotrolled
sheet annealing, and annealed steel sheets
were obtained. Next, on the annealed steel sheets,
cold rolling was performed one time, or cold rolling
was performed two times with intermediate annealing
performed therebetween, and cold-rolled steel sheets
each having a sheet thickness of 0.30 mm were
obtained. As the intermediate annealing, box
annealing for holding at 950°C for 10 hours, or
continuous annealing for holding at a temperature of
900°C to llOO°C for 30 seconds was performed. The
other slabs were each rough rolled to a sheet
thickness of 10 mm in hot rolling, and then grinding
of front and back surfaces was performed, and thereby
ground sheets each having a thickness of 3 mm were
obtained. Next, the ground sheets were each heated
at 1150°C for 30 minutes, and then subjected to finish
rolling in one pass at 850°C under the condition of a
strain rate being 35s-l, and hot-rolled steel sheets
each having a sheet thickness of 1.0 mm were
obtained. Thereafter, hot-rolled sheet annealing to
perform holding at 1000°C for 30 seconds was
- 30 -
performed, and then cold-rolled steel sheets each
having a sheet thickness of 0.30 mm were obtained by
cold rolling.
[0060] After the cold rolling, on the cold-rolled
steel sheets, finish annealing for holding at 1000°C
for 1 second was performed, and electrical steel
sheets were obtained. Measurement by the abovedescribed
Schultz method was performed to reveal that
the accumulation degree Icubew as 0.1 to 10.0 and the
accumulation degree was 0.3 to 23.8 as
represented in Table 1 below. Measurement by the
above-described method using a vertical section
structure photograph was performed to reveal that the
average crystal grain diameter was 66 pm to 72 pm.
[0061] A core loss and a magnetic flux density of
respective samples were measured. As the core loss,
a core loss W15/400L and a core loss Wl5/400C were
measured. The core loss W15/400L is a core loss
obtained when magnetization is performed in the L
direction at a frequency of 400 Hz until the magnetic
flux density of 1.5T. The core loss W15/400C is a
core loss obtained when magnetization is performed in
the C direction at a frequency of 400 Hz until the
magnetic flux density of 1.5T. As the magnetic flux
density, a magnetic flux density B50L and a magnetic
flux density B50C were measured. The magnetic flux
density B50L is a magnetic flux density in the L
direction at being magnetized by a magnetizing force
of 5000 A/m. The magnetic flux density B50C is a
magnetic flux density in the C direction at being
magnetized by a magnetizing force of 5000 A/m. The
core loss W15/400L and the magnetic flux density B50L
were measured without application of a compressive
stress, and the core loss W15/400C and the magnetic
flux density B50C were measured in a state where a
compressive stress of 40 MPa was applied in the C
direction. The magnetic property was measured by a
55-mm-square single sheet tester (SST) in conformity
with JIS C 2556. Results thereof are represented in
Table 1, and Fig. 1 and Fig. 2. In Table 1, each
underline indicates that a corresponding numerical
value is outside the present invention range or
preferred range. In Table 1, the saturation magnetic
flux density Bs was obtained by the following
expression. [Si], [Mn], and [All are the contents of
Si, Mn, and A1 respectively.
Bs = 2.1561 - 0.0413 x [Si] - 0.0198 x [Mn] -
0.0604 x [All
[0062] [Table 11
TABLE 1
10 110.0 14.0 1 14.0 1 -0.40 1 71 1 1.83 1 1.73 1 0.886 1 0.838 1 0.048 1 39.6 1 70.5 1 COMPARATIVE EXAMPLE
11 (01 10.3 1 & 1 3.00 / 69 1 1.72 1 1.63 1 0.833 1 0.789 1 0.044 1 42.2 1 69.2 1 COMPARATIVE EXAMPLE
[ 0 0 6 3 ] As illustrated in Fig. 1, the higher the
value of "I,,,, t I C u b e 8 ' was, the lower the core loss
W15/400L was. This is inferred because the Goss
orientation and the Cube orientation both are the
orientation contributing to the improvement in the
magnetic properties in the L direction, as described
above.
[ 0 0 6 4 ] As illustrated in Fig. 2, in the case of the
value of " I C U b e q ' being 2 . 5 or more, the higher the
value of " I G / I C U bwa"s , the lower the core loss
W15/400C was. This is inferred because as the value
of l l I ~ o s s / I C u b e "i s higher, the ratio of crystal grains
in the Cube orientation to be likely to be affected
by the compressive stress in the C direction is
higher, as described above.
[ 0 0 6 5 ] As illustrated in Fig. 2, in the case of the
value of ' ' I c ~ ~be~in' g' less than 2 . 5 , the core loss
W15/400C was not as low as the case of the value of
"ICubeb"e ing 2 . 5 or more. This is inferred because
the crystal grains in the Cube orientation
contributing to the improvement in the magnetic
properties in the C direction were decreased, as
described above.
[ 0 0 6 6 ] In Fig. 3, the accumulation degree I,,,, and
the accumulation degree Icube of the above-described
invention examples and comparative examples, and the
relations of Expression 1, Expression 2, and
Expression 3 are illustrated. As is clear from Fig.
1, Fig. 2 , and Fig. 3, when all of Expression 1,
- 34 -
Expression 2, and Expression 3 were satisfied,
excellent magnetic properties in the L direction were
able to be obtained under no stress and excellent
magnetic properties in the C direction were able to
be obtained under the compressive stress in the C
direction.
[0067] Fig.4 illustrates the relationship between
the ratio of the magnetic flux density B50L to the
saturation magnetic flux density Bs (B5OL/Bs) and the
ratio of the magnetic flux density B50C to the
saturation magnetic flux density Bs (B50C/Bs). As
illustrated in Fig. 4, the invention examples satisfy
Expression 7 and Expression 8.
B50C/Bs 1 0.790 ... Expression 7
(B50L - B50C)/Bs 2 0.070 ... Expression 8
[0068] (Second Test)
In the second test, the relationship of the
condition of the intermediate annealing, the
accumulation degree, and the magnetic properties was
examined. First, a plurality of hot-rolled steel
sheets each containing, in mass%, C: 0.002%, Si:
1.99%, Al: 0.0190%, Mn: 0.20%, S: 0.002%, N: 0.002%,
and P: 0.0128, and balance being composed of Fe and
impurities and having a sheet thickness of 2.5 mm
were fabricated. Next, on the hot-rolled steel
sheets, box hot-rolled sheet annealing for holding at
a temperature of 800°C for 10 hours was performed to
obtain annealed steel sheets. The average crystal
grain diameter of the annealed steel sheets was 70
pm. Thereafter, first cold rolling with a first cold
rolling ratio of 60% was performed on the annealed
steel sheets, to obtain intermediate cold-rolled
steel sheets each having a sheet thickness of 1.0 mm.
Subsequently, on the intermediate cold-rolled steel
sheets, intermediate annealing was performed under
the condition represented in Table 2 below, to obtain
intermediate annealed steel sheets. As represented
in Table 2, the average crystal grain diameter of the
intermediate annealed steel sheets was 71 pm to 355
pm. Next, on the intermediate annealed steel sheets,
second cold rolling was performed, to obtain coldrolled
steel sheets each having a sheet thickness of
0.30 mm. Thereafter, on the cold-rolled steel
sheets, finish annealing for holding at 1000°C for 15
seconds was performed, to obtain electrical steel
sheets. As a result of a measurement by the abovedescribed
Schultz method, it was revealed that the
accumulation degree Icube was 2.3 to 4.1 and the
accumulation degree I,,,, was 6.5 to 24.5 as
represented in Table 2 below. As a result of a
measurement by the above-described method using a
vertical section structure photograph, it was
revealed that the average crystal grain diameter was
70 pm to 82 pm as represented in Table 2.
[0069] The magnetic flux density B50L and the
magnetic flux density B50C were measured in the same
manner as in the first test. Results thereof are
represented in Table 2. In Table 2, each underline
i n d i c a t e s t h a t a c o r r e s p o n d i n g n u m e r i c a l v a l u e is
o u t s i d e t h e p r e s e n t i n v e n t i o n r a n g e o r p r e f e r r e d
r a n g e .
[0070] [ T a b l e 21
TABLE 2
STEELSHEET
1 27 ~CONT~NUOUS~ 1120°C 130 SECONDS~ 221 14.1 1 8.7 1 12.8 1 2.12 / 80 1 0.901 1 0.814 1 0.087 I INVENTION EXAMPLE /
[0071] As represented in Table 2, in Samples No. 23
to No. 27, the intermediate annealing was performed
under the preferred condition, and thereby a desired
texture was able to be obtained and the magnetic
properties satisfying Expression 7 and Expression 8
were able to be obtained. On the other hand, in
Samples No. 21 and No. 22, the condition of the
intermediate annealing was outside the preferred
range, and therefore a desired texture was not able
to be obtained and the magnetic properties did not
satisfy Expression 8.
[0072] (Third Test)
In the third test, the relationship of the
component, the accumulation degree, and the magnetic
properties was examined. First, a plurality of hotrolled
steel sheets each containing the components
represented in Table 3 and further containing Ti:
0.002%, V: 0.003%, and Nb: 0.002%, and balance being
composed of Fe and impurities and having a sheet
thickness of 2.0 mm were fabricated. Next, as hotrolled
sheet annealing, continuous annealing for
holding at lOOO0C for 30 seconds was performed, to
obtain annealed steel sheets. The average crystal
grain diameter of the annealed steel sheets was 72 pm
to 85 pm. Thereafter, first cold rolling with a
first cold rolling ratio of 70% was performed on the
annealed steel sheets, to obtain intermediate coldrolled
steel sheets each having a sheet thickness of
0.6 mm. Subsequently, on the intermediate coldrolled
steel sheets, box intermediate annealing for
holding at 950°C for 100 hours was performed, to
obtain intermediate annealed steel sheets. The
average crystal grain diameter of the intermediate
annealed steel sheets was 280 pm to 343 pm. Next, on
the intermediate annealed steel sheets, second cold
rolling with a second cold rolling ratio of 58% was
performed, to obtain cold-rolled steel sheets each
having a sheet thickness of 0.25 mm. Thereafter, on
the cold-rolled steel sheets, finish annealing for
holding at a temperature of 1050°C for 30 seconds was
performed, to obtain electrical steel sheets. As a
result of a measurement by the above-described
Schultz method, it was revealed that the accumulation
degree Icuhewa s 1.9 to 3.9 and the accumulation degree
I Gwas~ 8.~0 t~o 21 .3 as represented in Table 4 below.
As a result of a measurement by the above-described
method using a vertical section structure photograph,
it was revealed that the average crystal grain
diameter is 105 pm to 123 vm as represented in Table
4.
[0073] Then, the magnetic flux density B50L and the
magnetic flux density B50C were measured in the same
manner as in the first test. Results thereof are
represented in Table 4. In Table 3 or Table 4, each
underline indicates that a corresponding numerical
value is outside the present invention range or
preferred range.
LO0741 [Table 31
TABLE 3
[ 0 0 7 5 ] [ T a b l e 4 1

therefore a desired texture was able to be obtained
and the magnetic properties satisfying Expression 7
and Expression 8 were able to be obtained. On the
other hand, in Samples No. 39 to No. 41, the content
of A1 or the content of Si was outside the present
invention range, and therefore a desired texture was
not able to be obtained and the magnetic properties
did not satisfy Expression 8.
[0077] (Fourth Test)
In the fourth test, the relationship between the
conditions of the hot-rolled sheet annealing, the
first cold rolling, and the second cold rolling and
the magnetic properties was examined. First, hotrolled
steel sheets each containing, in mass%, C:
0.002%, Si: 2.15%, Al: 0.0050%, Mn: 0.20%, S: 0.003%,
N: 0.001%, P: 0.016%, Sn: 0.003%, Sb: 0.002%, Cr:
0.02%, Cu: 0.01%, Ni: 0.01%, Ti: 0.003%, V: 0.001%,
and Nb: 0.002%, and balance being composed of Fe and
impurities and having a sheet thickness of 1.6 mm to
2.5 mm were fabricated. Next, on the hot-rolled
steel sheets, hot-rolled sheet annealing was
performed under the condition represented in Table 5
below, to obtain annealed steel sheets. As
represented in Table 5, the average crystal grain
diameter of the annealed steel sheets was 24 pm to
135 vm. Thereafter, first cold rolling with a first
cold rolling ratio of 35% to 75% was performed on the
annealed steel sheets, to obtain intermediate coldrolled
steel sheets each having a sheet thickness of
0.5 mm to 1.3 mm. Subsequently, on the intermediate
cold-rolled steel sheets, box intermediate annealing
for holding at 950°C for 10 hours was performed, to
obtain intermediate annealed steel sheets. The
average crystal grain diameter of the intermediate
annealed steel sheets was 295 pm to 314 pm. Next, on
the intermediate annealed steel sheets, second cold
rolling with a second cold rolling ratio of 30% to
86% was performed, to obtain cold-rolled steel sheets
each having a sheet thickness of 0.15 mm to 0.35 mm.
Thereafter, on the cold-rolled steel sheets, finish
annealing for holding at a temperature of 800°C to
1120°C for a time period of 15 seconds to 60 seconds
was performed, to obtain electrical steel sheets. As
a result of a measurement by the above-described
Schultz method, it was revealed that the accumulation
degree ICube was 1.5 to 3.7 and the accumulation degree
IGoswsa s 5.5 to 16.4 as represented in Table 6 below.
As a result of a measurement by the above-described
method using a vertical section structure photograph,
it was revealed that the average crystal grain
diameter is 32 pm to 192 pm as represented in Table
6.
[0078] The magnetic flux density B50L and the
magnetic flux density B50C were measured in the same
manner as in the first test. Results thereof are
represented in Table 6. In Table 5 or Table 6, each
underline indicates that a corresponding numerical
value is outside the present invention range or
preferred range.
[0079] [Table 51
TABLE 5
[0080] [Table 61
TABLE 6
[0081] In Samples No. 51 to No. 53, the hot-rolled
sheet annealing, the first cold rolling, and the
second cold rolling were performed under the
preferred conditions, and therefore a desired texture
was able to be obtained and the magnetic properties
satisfying Expression 7 and Expression 8 were able to
be obtained. On the other hand, in Samples No. 54 to
No. 57, the condition of the hot-rolled sheet
annealing, the first cold rolling, or the second cold
rolling was outside the preferred range, and
therefore a desired texture was not able to be
obtained and the magnetic properties did not satisfy
Expression 7 or Expression 8.
[0082] (Fifth Test)
In the fifth test, 4-pole 6-slot interior
permanent magnet ( I P M ) divided iron core motors were
fabricated using the electrical steel sheets of
Sample'No. 3, Sample No. 7, and Sample No. 8 as an
iron core material,,of which torque constants under
the condition of a load torque being lNm, 2Nm, and
3Nm were measured. The IMP divided iron core motor
was set so as to make the L direction of the
electrical steel sheet parallel to a teeth part of a
motor iron core and make the C direction thereof
parallel to a back yoke part thereof. The torque
constant is a value obtained by normalizing an
appropriate torque by a current value necessary for
outputting the torque. In other words, the torque
constant corresponds to a torque per 1A of current,
and the higher the torque constant is, the more
preferable it is. Results thereof are represented in
Table 7. In Table 7, each underline indicates that a
corresponding numerical value is outside the present
invention range.
[0083] [Table 71
TABLE 7
[0084] As represented in Table 7, the torque
constant of the divided iron core motor using Sample
No. 3 as an iron core material was more excellent
than the torque constants of the divided iron core
motors using Sample No. 7 and Sample No. 8 as an iron
core material under all the load torques. On the
other hand, the torque constant of the divided iron
core motor using Sample No. 7 or Sample No. 8 as an
iron core material was low under the condition of
particularly the load torque being low.
INDUSTRIAL APPLICABILITY
[0085] The present invention may be used for, for
example, industries of manufacturing an electrical
steel sheet and industries of using the electrical
steel sheet such as motors.

CLAIMS
[Claim 11 An electrical steel sheet, comprising:
a chemical composition represented by, in mass%:
C: 0.010% or less;
Si: 1.30% to 3.50%;
Al: 0.0000% to 1.6000%;
Mn: 0.01% to 3.00%;
S: 0.0100% or less;
N: 0.010% or less;
P: 0.000% to 0.150%;
Sn: 0.000% to 0.150%;
Sb: 0.000% to 0.150%;
Cr: 0.000% to 1.000%;
Cu: 0.000% to 1.000%;
Ni: 0.000% to 1.000%;
Ti: 0.010% or less;
V: 0.010% or less;
Nb: 0.010% or less; and
balance: Fe and impurities;
a crystal grain diameter of 20 pm to 300 pm; and
a texture satisfying Expression 1, Expression 2,
and Expression 3 when the accumulation degree of the
(001) [loo] orientation is represented as ICube and the
accumulation degree of the (011)[100] orientation is
represented as I G ~ ~ ~ ,
IGOS+S IcUbe2 10. 5 . . .Expression 1
I G ~ ~2~ 0./50I .~ . . E~xpr~es~sio n 2
Icube > 2. 5 . . . Expression 3.
[Claim 21 The electrical steel sheet according to
claim 1, wherein the texture satisfies Expression 4,
Expression 5, and Expression 6,
I Gf ~Icu~be 2~ 10 .7 . . .Expression 4
IG,,,/Ic,~, 2 0.52 . . .Expression 5
Icube 2 2. 7 . . . Expression 6.
[Claim 31 The electrical steel sheet according to
claim 1 or 2, further comprising:
a magnetic property satisfying Expression 7 and
Expression 8 when a saturation magnetic flux density
is represented as Bs, a magnetic flux density in a
rolling direction at being magnetized by a
magnetizing force of 5000 A/m is represented as B50L,
and a magnetic flux density in a direction
perpendicular to the rolling direction and a sheet
thickness direction at being magnetized by a
magnetizing force of 5000 A/m is represented as B50C,
BSOC/Bs 2 0.790 ... Expression 7
(B50L - B50C)/Bs 0.070 ... Expression 8.
[Claim 41 The electrical steel sheet according to
claim 3, wherein the magnetic property satisfies
Expression 9,
(B50L - BSOC)/Bs 2 0.075 . . . Expression 9.
[Claim 51 The electrical steel sheet according to
claim 3 or 4, wherein the magnetic property satisfies
Expression 10,
B5OC/Bs 0.825 . . . Expression 10.
[Claim 61 The electrical steel sheet according to
any one of claims 1 to 5, wherein in the chemical
composition,
P: 0.001% to 0.150%,
Sn: 0.001% to 0.150%, or
Sb: 0.001% to 0.150%, or any combination thereof
is satisfied.
[Claim 71 The electrical steel sheet according to
any one of claims 1 to 6, wherein in the chemical
composition,
Cr: 0.005% to 1.000%,
Cu: 0.005% to 1.000%,
Ni: 0.005% to 1.000%, or any combination thereof
is satisfied.
[Claim 81 The electrical steel sheet according to
any one of claims 1 to 7, wherein a thickness thereof
is 0.10 mm to 0.50 mm.