DESCRIPTION
TITLE OF INVENTION: NON-ORIENTED ELECTRICAL STEEL
SHEET, METHOD OF MANUFACTURING THE SAME, LAMINATE FOR
MOTOR I R O N CORE, AND METHOD OF MANUFACTURING THE SAME
TECHNICAL FIELD
[ 0 0 0 1 ] The p r e s e n t i n v e n t i o n r e l a t e s t o a nono
r i e n t e d e l e c t r i c a l s t e e l s h e e t s u i t a b l e f o r an i r o n
c o r e m a t e r i a l of an e l e c t r i c a p p a r a t u s , a method o f
m a n u f a c t u r i n g t h e same, and s o on.
BACKGROUND ART
[ 0 0 0 2 ] I n r e c e n t y e a r s , a motor r o t a t i n g a t a h i g h
s p e e d and h a v i n g a r e l a t i v e l y l a r g e c a p a c i t y i s
i n c r e a s i n g l y used a s a d r i v i n g motor o f a n e l e c t r i c
v e h i c l e , a h y b r i d v e h i c l e , and t h e l i k e . For t h i s
r e a s o n , an i r o n c o r e m a t e r i a l t o be u s e d f o r a
d r i v i n g motor i s r e q u i r e d t o have a c h i e v e m e n t o f l o w
c o r e l o s s i n a r a n g e of s e v e r a l h u n d r e d Hz t o s e v e r a l
kHz h i g h e r t h a n a commercial f r e q u e n c y . F u r t h e r , a n
i r o n c o r e t o b e u s e d f o r a r o t o r i s a l s o r e q u i r e d t o
h a v e a c e r t a i n m e c h a n i c a l s t r e n g t h i n o r d e r t o
w i t h s t a n d a c e n t r i f u g a l f o r c e and a stress v a r i a t i o n .
An i r o n c o r e m a t e r i a l t o be used f o r o t h e r t h a n a
d r i v i n g motor of a v e h i c l e sometimes n e e d s t o have
s u c h a r e q u i r e m e n t .
[ 0 0 0 3 ] C o n v e n t i o n a l l y , some t e c h n i q u e s have been
p r o p o s e d whose p u r p o s e s a r e c o r e l o s s r e d u c t i o n ,
s t r e n g t h improvement a n d / o r t h e l i k e ( P a t e n t
L i t e r a t u r e s 1 t o 1 2 ) .
[0004] However, w i t h t h e s e t e c h n i q u e s , it i s
d i f f i c u l t t o a t t a i n a c h i e v e m e n t o f t h e c o r e l o s s
r e d u c t i o n and t h e s t r e n g t h i m p r o v e m e n t . F u r t h e r ,
some o f t h e t e c h n i q u e s h a v e d i f f i c u l t y i n a c t u a l l y
m a n u f a c t u r i n g a n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t .
CITATION LIST
PATENT LITERATURE
[0005] P a t e n t L i t e r a t u r e 1: J a p a n e s e L a i d - o p e n Pa t e n t
P u b l i c a t i o n No. 02-008346
P a t e n t L i t e r a t u r e 2: J a p a n e s e L a i d - o p e n P a t e n t
P u b l i c a t i o n No. 06-330255
P a t e n t L i t e r a t u r e 3: J a p a n e s e L a i d - o p e n P a t e n t
P u b l i c a t i o n No. 2006-009048
P a t e n t L i t e r a t u r e 4 : J a p a n e s e L a i d - o p e n P a t e n t
P u b l i c a t i o n No. 2006-070269
P a t e n t L i t e r a t u r e 5: J a p a n e s e L a i d - o p e n P a t e n t
P u b l i c a t i o n No. 10-018005
P a t e n t L i t e r a t u r e 6: J a p a n e s e L a i d - o p e n P a t e n t
P u b l i c a t i o n No. 2004-084053
P a t e n t L i t e r a t u r e 7 : J a p a n e s e L a i d - o p e n P a t e n t
P u b l i c a t i o n No. 2004-183066
P a t e n t L i t e r a t u r e 8 : J a p a n e s e L a i d - o p e n P a t e n t
P u b l i c a t i o n No. 2007-039754
P a t e n t L i t e r a t u r e 9: J a p a n e s e L a i d - o p e n P a t e n t
P u b l i c a t i o n No. 10-88298
P a t e n t L i t e r a t u r e 1 0 : I n t e r n a t i o n a l P u b l i c a t i o n
Pamphlet No. W02009/128428
P a t e n t L i t e r a t u r e 11: J a p a n e s e L a i d - o p e n P a t e n t
P u b l i c a t i o n No. 2003-105508
P a t e n t L i t e r a t u r e 12: J a p a n e s e L a i d - o p e n P a t e n t
P u b l i c a t i o n No. 11-229094
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[ 0 0 0 6 ] The p r e s e n t i n v e n t i o n h a s a n o b j e c t t o
p r o v i d e a n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t c a p a b l e
of a t t a i n i n g a c h i e v e m e n t o f a c o r e l o s s r e d u c t i o n a n d
a s t r e n g t h i m p r o v e m e n t , a method o f m a n u f a c t u r i n g t h e
same, and s o on.
SOLUTION TO PROBLEM
[ 0 0 0 7 ] The p r e s e n t i n v e n t i o n h a s b e e n made i n o r d e r
t o s o l v e t h e a b o v e - d e s c r i b e d p r o b l e m s , and t h e g i s t
t h e r e o f i s a s f o l l o w s .
[ 0 0 0 8 ] (1) A n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t
c o n t a i n i n g :
i n mass%,
C : g r e a t e r t h a n 0.01% a n d 0 . 0 5 % o r l e s s ;
S i : n o t l e s s t h a n 2.0% n o r more t h a n 4 . 0 % ;
Mn: n o t l e s s t h a n 0.05% n o r more t h a n 0 . 5 % ;
A l : n o t l e s s t h a n 0.01% n o r more t h a n 3.0%; and
a t l e a s t one s e l e c t e d from t h e g r o u p c o n s i s t i n g
o f T i , V, Z r , and N b ,
a b a l a n c e being composed o f Fe and i n e v i t a b l e
i m p u r i t i e s ,
w h e r e i n
when c o n t e n t s o f T i , V, Z r , Nb, and C ( m a s s % ) a r e
r e p r e s e n t e d a s [ T i ] , [ V ] , [ Z r ] , [Nb], and [C]
r e s p e c t i v e l y , a v a l u e o f a p a r a m e t e r Q r e p r e s e n t e d by
"Q = ( [ T i ] / 4 8 + [ V ] / 5 1 + [ Z r ] / 9 1 + [ N b ] / 9 3 ) / ( [ C ] / 1 2 ) "
i s n o t less t h a n 0 . 9 n o r more t h a n 1.1,
a m a t r i x o f a m e t a l s t r u c t u r e i s a f e r r i t e p h a s e ,
t h e m e t a l s t r u c t u r e d o e s n o t i n c l u d e a nonr
e c r y s t a l l i z e d s t r u c t u r e ,
a n a v e r a g e g r a i n s i z e of f e r r i t e g r a i n s
c o n s t i t u t i n g t h e f e r r i t e p h a s e i s n o t less t h a n 10 pm
n o r more t h a n 200 pm,
a p r e c i p i t a t e c o n t a i n i n g a t l e a s t one s e l e c t e d
from t h e g r o u p c o n s i s t i n g of T i , V , Z r , and Nb e x i s t s
w i t h a d e n s i t y o f 10 ym-3 o r more i n t h e f e r r i t e
g r a i n , a n d
an a v e r a g e g r a i n s i z e of t h e p r e c i p i t a t e i s n o t
l e s s t h a n 0.002 pm n o r more t h a n 0 . 2 pm.
[ 0 0 0 9 ] ( 2 ) The n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t
a c c o r d i n g t o ( I ) , f u r t h e r c o n t a i n i n g :
i n mass%, a t l e a s t one s e l e c t e d from t h e g r o u p
c o n s i s t i n g of
N : n o t l e s s t h a n 0 . 0 0 1 % n o r more t h a n 0 . 0 0 4 % ;
Cu: n o t less t h a n 0.5% n o r more t h a n 1 . 5 % ; and
Sn: n o t less t h a n 0.05% n o r more t h a n 0 . 5 % .
[ 0 0 1 0 ] ( 3 ) The n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t
a c c o r d i n g t o (1) o r ( 2 ) , w h e r e i n t h e p r e c i p i t a t e i s
a t l e a s t one s e l e c t e d from t h e g r o u p c o n s i s t i n g o f
c a r b i d e , n i t r i d e , and c a r b o n i t r i d e .
[OOlJ.] ( 4 ) A method o f m a n u f a c t u r i n g a n o n - o r i e n t e d
electrical steel sheet including:
performing hot rolling of a slab heated to a
temperature of not lower than llOO°C nor higher than
1330°C to obtain a hot-rolled steel sheet;
performing cold rolling of the hot-rolled steel
sheet to obtain a cold-rolled steel sheet; and
performing finish annealing of the cold-rolled
steel sheet at a temperature of not lower than 850°C
nor higher than llOO°C,
wherein
the slab contains:
in mass%,
C: greater than 0.01% and 0.05% or less;
Si: not less than 2.0% nor more than 4.0%;
Mn: not less than 0.05% nor more than 0.5%;
Al: not less than 0.01% nor more than 3.0%; and
at least one selected from the group consisting
of Ti, V, Zr, and Nb,
a balance being composed of Fe and inevitable
impurities, and
when contents of Ti, V, Zr, Nb, and C (mass%) are
represented as [Ti], [V], [Zr], [Nb], and [C]
respectively, a value of a parameter Q represented by
"Q = ([Ti] /48 t [V]/51 + [Zr]/91 + [Nb]/93) / ([C]/12)"
is not less than 0.9 nor more than 1.1.
[0012] (5) The method of manufacturing the nonoriented
electrical steel sheet according to (4),
wherein the slab further contains:
i n mass%, a t l e a s t one s e l e c t e d f r o m t h e g r o u p
c o n s i s t i n g of
N: n o t less t h a n 0.001% n o r more. t h a n 0.004%;
Cu: n o t l e s s t h a n 0 . 5 % n o r more t h a n 1 . 5 % ; a n d
Sn: n o t less t h a n 0.05% n o r more t h a n 0 . 5 % .
[0013] ( 6 ) The method o f m a n u f a c t u r i n g t h e nono
r i e n t e d e l e c t r i c a l s t e e l s h e e t a c c o r d i n g t o ( 4 ) o r
( 5 ) , f u r t h e r i n c l u d i n g , b e f o r e t h e p e r f o r m i n g c o l d
r o l l i n g , p e r f o r m i n g h o t - r o l l e d s h e e t a n n e a l i n g of t h e
h o t - r o l l e d s t e e l s h e e t .
[0014] ( 7 ) A l a m i n a t e f o r a m o t o r i r o n c o r e
i n c l u d i n g :
n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s l a m i n a t e d t o
one a n o t h e r ,
w h e r e i n
e a c h of t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s
c o n t a i n s :
i n mass%,
C: g r e a t e r t h a n 0.01% and 0 . 0 5 % o r less;
S i : n o t less t h a n 2.0% n o r more t h a n 4 . 0 % ;
Mn: n o t less t h a n 0 . 0 5 % n o r more t h a n 0,5%;
A l : n o t l e s s t h a n 0.01% n o r more t h a n 3 . 0 % ; a n d
a t l e a s t one s e l e c t e d from t h e g r o u p c o n s i s t i n g
o f T i , V, Z r , and N b ,
a b a l a n c e b e i n g composed of Fe and i n e v i t a b l e
i m p u r i t i e s ,
when c o n t e n t s of T i , V, Z r , Nb, and C ( m a s s % ) a r e
r e p r e s e n t e d a s [ T i ] , [ V ] , [ Z r ] , [ N b ] , and [ C ]
r e s p e c t i v e l y , a v a l u e of a p a r a m e t e r Q r e p r e s e n t e d by
"Q = ( [ T i ] / 4 8 + [ V ] / 5 1 + [ Z r ] / 9 1 + [ N b ] / 9 3 ) / ( [ C ] / 1 2 ) "
i s n o t l e s s t h a n 0 . 9 nor more t h a n 1.1,
a m a t r i x o f a m e t a l s t r u c t u r e is a f e r r i t e p h a s e ,
t h e m e t a l s t r u c t u r e d o e s n o t i n c l u d e a nonr
e c r y s t a l l i z e d s t r u c t u r e ,
an a v e r a g e g r a i n s i z e o f f e r r i t e g r a i n s
c o n s t i t u t i n g t h e f e r r i t e p h a s e i s n o t l e s s t h a n 10 pm
n o r more t h a n 200 pm,
a p r e c i p i t a t e c o n t a i n i n g a t l e a s t one s e l e c t e d
f r o m t h e g r o u p c o n s i s t i n g o f T i , V, Z r , a n d N b e x i s t s
w i t h a d e n s i t y of 10 pm-3 o r more i n t h e f e r r i t e
g r a i n , and
an a v e r a g e g r a i n s i z e o f t h e p r e c i p i t a t e i s n o t
less t h a n 0 . 0 0 2 pm n o r more t h a n 0 . 2 pm.
[ 0 0 1 5 ] ( 8 ) The l a m i n a t e f o r t h e m o t o r i r o n c o r e
a c c o r d i n g t o ( 7 ) , w h e r e i n e a c h o f t h e n o n - o r i e n t e d
e l e c t r i c a l s t e e l s h e e t s f u r t h e r c o n t a i n s :
i n mass%, a t l e a s t one s e l e c t e d from t h e g r o u p
c o n s i s t i n g o f
N: n o t l e s s t h a n 0.001% n o r more t h a n 0 . 0 0 4 % ;
Cu: n o t l e s s t h a n 0.5% n o r more t h a n 1 . 5 % ; and
Sn: n o t l e s s t h a n 0.05% n o r more t h a n 0 . 5 % .
[ 0 0 1 6 ] ( 9 ) The l a m i n a t e f o r t h e m o t o r i r o n c o r e
a c c o r d i n g t o ( 7 ) o r ( 8 ) , w h e r e i n t h e p r e c i p i t a t e i s
a t l e a s t one s e l e c t e d from t h e g r o u p c o n s i s t i n g of
c a r b i d e , n i t r i d e , and c a r b o n i t r i d e .
[0017] ( 1 0 ) A method of m a n u f a c t u r i n g a l a m i n a t e f o r
a m o t o r i r o n c o r e i n c l u d i n g :
l a m i n a t i n g n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s
t o o n e a n o t h e r t o o b t a i n a l a m i n a t e ; a n d
a n n e a l i n g t h e l a m i n a t e u n d e r a c o n d i t i o n i n which
a s o a k i n g t e m p e r a t u r e i s n o t l o w e r t h a n 400°C n o r
h i g h e r t h a n 800°C, a s o a k i n g t i m e p e r i o d i s n o t
s h o r t e r t h a n 2 m i n u t e s n o r l o n g e r t h a n 10 h o u r s , and
an a v e r a g e c o o l i n g r a t e from t h e s o a k i n g t e m p e r a t u r e
t o 300°C i s n o t less t h a n O.OOOl°C/sec n o r more t h a n
0. 1 ° C / s e c ,
w h e r e i n
e a c h of t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s
c o n t a i n s :
i n mass%,
C : g r e a t e r t h a n 0 . 0 1 % a n d 0.05% o r less;
S i : n o t l e s s t h a n 2 . 0 % n o r more t h a n 4 . 0 % ;
Mn: n o t l e s s t h a n 0.05% n o r more t h a n 0 . 5 % ;
A l : n o t l e s s t h a n 0.01% n o r more t h a n 3 . 0 % ; and
a t l e a s t o n e s e l e c t e d from t h e g r o u p c o n s i s t i n g
o f T i , V, Z r , and Nb,
a b a l a n c e b e i n g composed o f Fe and i n e v i t a b l e
i m p u r i t i e s ,
when c o n t e n t s of T i , V, Z r , Nb, and C (mass%) a r e
r e p r e s e n t e d a s [ T i ] , [ V ] , [ Z r ] , [Nb], a n d [C]
r e s p e c t i v e l y , a v a l u e o f a p a r a m e t e r Q r e p r e s e n t e d by
"Q = ( [ T i ] / 4 8 + [ V ] / 5 1 + [ Z r ] / 9 1 + [Nb] / 9 3 ) / ( [ C l / 1 2 ) "
i s n o t l e s s t h a n 0 . 9 n o r more t h a n 1.1,
a m a t r i x o f a m e t a l s t r u c t u r e i s a f e r r i t e p h a s e ,
t h e m e t a l s t r u c t u r e d o e s n o t i n c l u d e a nonr
e c r y s t a l l i z e d s t r u c t u r e ,
an a v e r a g e g r a i n s i z e o f f e r r i t e g r a i n s
c o n s t i t u t i n g t h e f e r r i t e p h a s e i s n o t l e s s t h a n 10 pm
n o r more t h a n 200 pm,
a p r e c i p i t a t e c o n t a i n i n g a t l e a s t one s e l e c t e d
from t h e g r o u p c o n s i s t i n g o f T i , V, Z r , a n d N b e x i s t s
w i t h a d e n s i t y of 10pm-' o r more i n t h e f e r r i t e g r a i n ,
and
an a v e r a g e g r a i n s i z e o f t h e p r e c i p i t a t e i s n o t
less t h a n 0.002 pm n o r more t h a n 0 . 2 pm.
[ 0 0 1 8 ] (11) The m e t h o d o f m a n u f a c t u r i n g t h e l a m i n a t e
f o r t h e m o t o r i r o n c o r e a c c o r d i n g t o ( l o ) , w h e r e i n
e a c h of t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s
f u r t h e r c o n t a i n s :
i n m a s s % , a t l e a s t one s e l e c t e d from t h e g r o u p
c o n s i s t i n g o f
N: n o t l e s s t h a n 0.001% n o r more t h a n 0 . 0 0 4 % ;
Cu: n o t less t h a n 0 . 5 % n o r more t h a n 1 . 5 % ; and
Sn: n o t l e s s t h a n 0:05% n o r more t h a n 0 . 5 % .
[ 0 0 1 9 ] ( 1 2 ) The m e t h o d o f m a n u f a c t u r i n g t h e l a m i n a t e
f o r t h e m o t o r i r o n c o r e a c c o r d i n g t o ( 1 0 ) o r (ll),
w h e r e i n t h e p r e c i p i t a t e i s a t l e a s t one s e l e c t e d from
t h e g r o u p c o n s i s t i n g o f c a r b i d e , n i t r i d e , a n d
c a r b o n i t r i d e .
ADVANTAGEOUS EFFECTS OF INVENTION
[ 0 0 2 0 ] A c c o r d i n g t o t h e p r e s e n t i n v e n t i o n , a
c o m p o s i t i o n and a s t r u c t u r e o f a n o n - o r i e n t e d
electrical steel sheet are defined appropriately, so
that it is possible to attain achievement of core
loss reduction and strength improvement.
DESCRIPTION OF EMBODIMENTS
[0021] First, there will be explained a non-oriented
electrical steel sheet according to an embodiment of
the present invention and a method of manufacturing
the same.
[0022] The non-oriented electrical steel sheet
according to the present embodiment has a
predetermined composition, a matrix of a metal
structure is a ferrite phase, and the metal structure
does not include a non-recrystallized structure.
Further, an average grain size of ferrite grains
constituting the ferrite phase is not less than 10 pm
nor more than 200 pm, a precipitate containing at
least one selected from the group consisting of Ti,
V, Zr, and Nb exists in the ferrite grain with a
density of 10 pm-3 or more, and an average grain size
of the precipitate is not less. than 0.002 pm nor more
than 0.2 pm. The constitution makes it possible to
attain achievement of core loss reduction and
strength improvement. As a result, it is possible to
greatly contribute to achievement of high efficiency
of a motor, and the like.
[0023] Further, in the method of manufacturing the
non-oriented electrical steel sheet according to the
embodiment, hot rolling of a slab heated to not lower
t h a n 1100°C n o r h i g h e r t h a n 1330°C a n d h a v i n g a
p r e d e t e r m i n e d c o m p o s i t i o n i s p e r f o r m e d t o o b t a i n a
h o t - r o l l e d s t e e l s h e e t . N e x t , c o l d r o l l i n g o f t h e
h o t - r o l l e d s t e e l s h e e t i s p e r f o r m e d t o o b t a i n a c o l d -
r o l l e d s t e e l s h e e t . N e x t , f i n i s h a n n e a l i n g o f t h e
c o l d - r o l l e d s t e e l s h e e t is p e r f o r m e d .
[ 0 0 2 4 ] Here, t h e c o m p o s i t i o n of t h e n o n - o r i e n t e d
e l e c t r i c a l s t e e l s h e e t w i l l b e e x p l a i n e d .
H e r e i n a f t e r , " % ' I b e i n g t h e u n i t o f a c o n t e n t means
" m a s s % . " F u r t h e r , t h e c o m p o s i t i o n o f t h e s l a b i s
h a n d e d o v e r t o t h a t o f t h e n o n - o r i e n t e d e l e c t r i c a l
s t e e l s h e e t a s it i s , and t h u s t h e c o m p o s i t i o n o f t h e
n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t t o be e x p l a i n e d
h e r e is a l s o a c o m p o s i t i o n of a s l a b t o b e u s e d f o r
m a n u f a c t u r i n g t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l
s h e e t . The n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t
a c c o r d i n g t o t h e embodiment c o n t a i n s , f o r e x a m p l e , C:
g r e a t e r t h a n 0.01% a n d 0.05% o r l e s s , S i : n o t l e s s
t h a n 2.0% n o r more t h a n 4 . 0 % , Mn: n o t l e s s t h a n 0 . 0 5 %
n o r more t h a n 0 . 5 % , and A l : n o t less t h a n 0 . 0 1 % n o r
more t h a n 3 . 0 % , and f u r t h e r c o n t a i n s a t l e a s t one
s e l e c t e d f r o m t h e g r o u p c o n s i s t i n g o f T i , V, Z r , and
N b . F u r t h e r , t h e b a l a n c e o f t h e n o n - o r i e n t e d
e l e c t r i c a l s t e e l s h e e t i s composed o f Fe and
i n e v i t a b l e i m p u r i t i e s , and when c o n t e n t s of T i , V,
Z r , Nb, and C ( m a s s % ) a r e r e p r e s e n t e d a s [ T i ] , [ V ] ,
[ Z r ] , [ N b ] , and [ C ] r e s p e c t i v e l y , a v a l u e of a
p a r a m e t e r Q r e p r e s e n t e d by "Q = ( [ T i ] / 4 8 + [ V ] / 5 1 +
[ Z r ] / 9 1 + [Nb] / 9 3 ) / ( [ C ] / 1 2 ) " i s n o t less t h a n 0 . 9 n o r
more t h a n 1.1.
[ 0 0 2 5 ]
C f o r m s f i n e p r e c i p i t a t e s w i t h T i , V, Zr, a n d Nb.
The f i n e p r e c i p i t a t e s c o n t r i b u t e t o i m p r o v e m e n t o f
s t r e n g t h o f s t e e l . When t h e C c o n t e n t i s 0.01% o r
l e s s , it i s n o t p o s s i b l e t o o b t a i n t h e p r e c i p i t a t e s
i n an amount s u f f i c i e n t f o r t h e i m p r o v e m e n t of t h e
s t r e n g t h . When t h e C c o n t e n t i s g r e a t e r t h a n 0 . 0 5 % ,
t h e p r e c i p i t a t e s a r e l i k e l y t o p r e c i p i t a t e c o a r s e l y .
The c o a r s e p r e c i p i t a t e s d o n o t c o n t r i b u t e t o t h e
improvement o f t h e s t r e n g t h e a s i l y . F u r t h e r , when
t h e p r e c i p i t a t e s p r e c i p i t a t e c o a r s e l y , c o r e l o s s i s
l i k e l y t o d e t e r i o r a t e . T h u s , t h e C c o n t e n t i s
g r e a t e r t h a n 0.01% and 0 . 0 5 % o r l e s s . F u r t h e r , t h e C
c o n t e n t i s p r e f e r a b l y 0 . 0 2 % o r more, a n d i s a l s o
p r e f e r a b l y 0.04% o r l e s s .
[ 0 0 2 6 ] < S i : n o t l e s s t h a n 2.0% n o r more t h a n 4 . 0 % >
S i i n c r e a s e s r e s i s t i v i t y o f s t e e l t o r e d u c e c o r e
l o s s . When t h e S i c o n t e n t is less t h a n 2 . 0 % , i t i s
n o t p o s s i b l e t o o b t a i n t h e e f f e c t s u f f i c i e n t l y . When
t h e S i c o n t e n t i s g r e a t e r t h a n 4 . 0 % , s t e e l is b r i t t l e
t o t h e r e b y make it d i f f i c u l t t o p e r f o r m r o l l i n g .
Thus, t h e S i c o n t e n t i s n o t l e s s t h a n 2.0% n o r more
t h a n 4 . 0 % . F u r t h e r , t h e S i c o n t e n t i s p r e f e r a b l y
3.5% o r l e s s .
[00271
Mn, s i m i l a r l y t o S i , i n c r e a s e s r e s i s t i v i t y o f
s t e e l t o r e d u c e c o r e l o s s . F u r t h e r , Mn c o a r s e n s
s u l f i d e t o make it h a r m l e s s . When t h e Mn c o n t e n t is
l e s s t h a n 0 . 0 5 % , i t i s n o t p o s s i b l e t o o b t a i n t h e
e f f e c t s s u f f i c i e n t l y . When t h e Mn c o n t e n t is g r e a t e r
t h a n 0 . 5 % , a m a g n e t i c f l u x d e n s i t y d e c r e a s e s o r
c r a c k i n g i s l i k e l y t o o c c u r d u r i n g c o l d r o l l i n g .
F u r t h e r , an i n c r e a s e i n c o s t i s s i g n i f i c a n t . Thus,
t h e Mn c o n t e n t i s n o t less t h a n 0.05% n o r more t h a n
0 . 5 % . F u r t h e r , t h e Mn c o n t e n t i s p r e f e r a b l y 0.1% o r
m o r e , and is a l s o p r e f e r a b l y 0.3% o r l e s s .
[ 0 0 2 8 ] < A l : n o t less t h a n 0 . 0 1 % n o r more t h a n 3.0%>
A l , s i m i l a r l y t o S i , i n c r e a s e s r e s i s t i v i t y o f
s t e e l t o r e d u c e c o r e l o s s . F u r t h e r , A1 f u n c t i o n s a s
a d e o x i d i z i n g m a t e r i a l . When t h e A 1 c o n t e n t is less
t h a n 0.01%, i t i s n o t p o s s i b l e t o o b t a i n t h e e f f e c t s
s u f f i c i e n t l y . When t h e A1 c o n t e n t i s g r e a t e r t h a n
3 . 0 % , s t e e l is b r i t t l e t o t h e r e b y make it d i f f i c u l t
t o p e r f o r m r o l l i n g . Thus, t h e A 1 c o n t e n t i s n o t less
t h a n 0.01% n o r more t h a n 3 . 0 % . F u r t h e r , t h e A1
c o n t e n t i s p r e f e r a b l y 0.3% o r more, a n d is - a l s o
p r e f e r a b l y 2.0% o r l e s s .
[ 0 0 2 9 ] < T i , V, Z r , and Nb>
T i , V, Z r , and Nb form f i n e p r e c i p i t a t e s w i t h C
a n d / o r N . The p r e c i p i t a t e s c o n t r i b u t e t o i m p r o v e m e n t
o f s t r e n g t h of s t e e l . When t h e v a l u e o f t h e
p a r a m e t e r Q i s l e s s t h a n 0 . 9 , C i s e x c e s s i v e w i t h
r e s p e c t t o T i , V, Z r , and N b , and t h u s C s t r o n g l y
t e n d s t o e x i s t i n a s o l i d s o l u t i o n s t a t e i n a s t e e l
s h e e t a f t e r t h e f i n i s h a n n e a l i n g . When C e x i s t s i n a
s o l i d s o l u t i o n s t a t e , m a g n e t i c a g i n g i s l i k e l y t o
o c c u r . When t h e v a l u e o f t h e p a r a m e t e r Q i s g r e a t e r
t h a n 1.1, C i s i n s u f f i c i e n t w i t h r e s p e c t t o T i , V ,
Z r , and Nb, and t h u s it i s d i f f i c u l t t o o b t a i n t h e
f i n e p r e c i p i t a t e s t o t h e r e b y make it i m p o s s i b l e t o
o b t a i n t h e d e s i r e d s t r e n g t h . T h u s , t h e v a l u e o f t h e
p a r a m e t e r Q i s n o t less t h a n 0 . 9 n o r more t h a n 1.1.
F u r t h e r , t h e v a l u e of t h e p a r a m e t e r Q is p r e f e r a b l y
0 . 9 5 o r more, a n d i s a l s o p r e f e r a b l y 1 . 0 5 o r l e s s .
[ 0 0 3 0 ] The n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t
a c c o r d i n g t o t h e embodiment may f u r t h e r c o n t a i n a t
l e a s t o n e s e l e c t e d from t h e g r o u p c o n s i s t i n g of N :
n o t l e s s t h a n 0 . 0 0 1 % n o r more t h a n 0 . 0 0 4 % , Cu: n o t
l e s s t h a n 0.5% n o r more t h a n 1.5%, and S n : n o t l e s s
t h a n 0.05% n o r more t h a n 0 . 5 % .
[ 0 0 3 1 ]
N , s i m i l a r l y t o C , f o r m s f i n e p r e c i p i t a t e s w i t h
T i , V, Z r , and N b . The f i n e p r e c i p i t a t e s c o n t r i b u t e
t o improvement of s t r e n g t h o f s t e e l . When t h e N
c o n t e n t i s less t h a n 0 . 0 0 1 % , it is n o t p o s s i b l e t o
o b t a i n t h e p r e c i p i t a t e s i n an amount s u f f i c i e n t f o r
t h e f u r t h e r i m p r o v e m e n t o f t h e s t r e n g t h . Thus, t h e N
c o n t e n t i s p r e f e r a b l y 0 . 0 0 1 % o r more. When t h e N
c o n t e n t i s g r e a t e r t h a n 0 . 0 0 4 % , t h e p r e c i p i t a t e s a r e
l i k e l y t o p r e c i p i t a t e c o a r s e l y . Thus, t h e N c o n t e n t
i s 0 . 0 0 4 % o r l e s s .
100321
The p r e s e n t i n v e n t o r s found o u t t h a t when Cu i s
c o n t a i n e d i n s t e e l , p r e c i p i t a t e s c o n t a i n i n g a t l e a s t
one s e l e c t e d from t h e group c o n s i s t i n g of T i , V, Z r ,
and Nb a r e l i k e l y t o p r e c i p i t a t e f i n e l y . The f i n e
p r e c i p i t a t e s c o n t r i b u t e t o improvement of s t r e n g t h of
t h e s t e e l . When t h e Cu c o n t e n t i s less t h a n 0 . 5 % , it
i s n o t p o s s i b l e t o o b t a i n t h e e f f e c t s u f f i c i e n t l y .
Thus, t h e Cu c o n t e n t i s p r e f e r a b l y 0.5% or more.
F u r t h e r , t h e Cu c o n t e n t i s more p r e f e r a b l y 0 . 8 % o r
more. When t h e Cu c o n t e n t i s g r e a t e r t h a n 1 . 5 % ,
s t e e l i s l i k e l y t o b e b r i t t l e . Thus, t h e Cu c o n t e n t
is 1.5% o r l e s s . F u r t h e r , t h e Cu c o n t e n t i s a l s o
p r e f e r a b l y 1.2% o r l e s s .
[0033] Though t h e r e a s o n why i n t h e c a s e of Cu b e i n g
c o n t a i n e d i n s t e e l , t h e a b o v e - d e s c r i b e d p r e c i p i t a t e s
p r e c i p i t a t e f i n e l y is u n c l e a r , t h e p r e s e n t i n v e n t o r s
s u p p o s e t h a t t h i s i s b e c a u s e a l o c a l c o n c e n t r a t i o n
d i s t r i b u t i o n of Cu is g e n e r a t e d i n a m a t r i x t o be a
p r e c i p i t a t i o n s i t e o f c a r b i d e . Thus, it i s a l s o
a c c e p t a b l e t h a t Cu h a s n o t p r e c i p i t a t e d when t h e
p r e c i p i t a t e i s made t o p r e c i p i t a t e . On t h e o t h e r
hand, a p r e c i p i t a t e of Cu c o n t r i b u t e s t o improvement
of s t r e n g t h o f a n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t .
Thus, it i s a l s o a c c e p t a b l e t h a t Cu p r e c i p i t a t e s .
[0034]
The p r e s e n t i n v e n t o r s a l s o found o u t t h a t when Sn
i s c o n t a i n e d i n s t e e l , p r e c i p i t a t e s c o n t a i n i n g a t
l e a s t o n e s e l e c t e d from t h e g r o u p c o n s i s t i n g o f T i ,
V, Z r , a n d Nb a r e l i k e l y t o p r e c i p i t a t e f i n e l y . The
f i n e p r e c i p i t a t e s c o n t r i b u t e t o i m p r o v e m e n t o f
s t r e n g t h of t h e s t e e l . When t h e Sn c o n t e n t i s less
t h a n 0 . 0 5 % , it i s n o t p o s s i b l e t o o b t a i n t h e e f f e c t
s u f f i c i e n t l y . Thus, t h e Sn c o n t e n t i s p r e f e r a b l y
0.05% o r more. F u r t h e r , t h e Sn c o n t e n t i s more
p r e f e r a b l y 0.08% o r more. When t h e Sn c o n t e n t i s
g r e a t e r t h a n 0 . 5 % , s t e e l i s l i k e l y t o b e b r i t t l e .
Thus, t h e Sn c o n t e n t i s 0.5% o r less. F u r t h e r , t h e
Sn c o n t e n t i s a l s o p r e f e r a b l y 0 . 2 % o r l e s s .
[ 0 0 3 5 ] < O t h e r components>
N i o f n o t less t h a n 0.5% n o r more t h a n 5% and P
o f n o t l e s s t h a n 0.005 -% n o r more t h a n 0.1% may a l s o
be c o n t a i n e d . N i and P c o n t r i b u t e t o s o l i d - s o l u t i o n
h a r d e n i n g of a s t e e l s h e e t and t h e l i k e .
[ 0 0 3 6 ] N e x t , t h e m e t a l s t r u c t u r e of t h e n o n - o r i e n t e d
e l e c t r i c a l s t e e l s h e e t w i l l be e x p l a i n e d .
LO0371 A s d e s c r i b e d a b o v e , t h e m a t r i x o f t h e m e t a l
s t r u c t u r e of t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t
a c c o r d i n g t o t h e embodiment is a f e r r i t e p h a s e , and
t h e n o n - r e c r y s t a l l i z e d s t r u c t u r e i s n o t i n c l u d e d i n
t h e m e t a l s t r u c t u r e . T h i s is b e c a u s e t h e nonr
e c r y s t a l l i z e d s t r u c t u r e i m p r o v e s s t r e n g t h b u t
d e t e r i o r a t e s t h e c o r e l o s s s i g n i f i c a n t l y . F u r t h e r ,
when t h e a v e r a g e g r a i n s i z e of t h e f e r r i t e g r a i n s
c o n s t i t u t i n g t h e f e r r i t e p h a s e i s l e s s t h a n 10 pm,
h y s t e r e s i s l o s s i n c r e a s e s . When t h e a v e r a g e g r a i n
s i z e of t h e f e r r i t e g r a i n s i s g r e a t e r t h a n 200 pm, an
e f f e c t of f i n e g r a i n h a r d e n i n g d e c r e a s e s
s i g n i f i c a n t l y . Thus, t h e a v e r a g e g r a i n s i z e o f t h e
f e r r i t e g r a i n s i s n o t less t h a n 1 0 pm nor more t h a n
200 pm. The a v e r a g e g r a i n s i z e of t h e f e r r i t e g r a i n s
i s p r e f e r a b l y 30 pm o r more, and i s a l s o p r e f e r a b l y
100 pm o r l e s s . F u r t h e r , t h e a v e r a g e g r a i n s i z e of
t h e f e r r i t e g r a i n s i s more p r e f e r a b l y 60 pm o r l e s s .
[ 0 0 3 8 ] I n t h e embodiment, p r e c i p i t a t e s c o n t a i n i n g a t
l e a s t one s e l e c t e d from t h e group c o n s i s t i n g of T i ,
V, Z r , and Nb e x i s t s i n t h e f e r r i t e g r a i n . A s t h e
p r e c i p i t a t e s a r e s m a l l e r and a number d e n s i t y of t h e
p r e c i p i t a t e s i s h i g h e r , t h e h i g h e r s t r e n g t h can be
o b t a i n e d . F u r t h e r , t h e s i z e of t h e p r e c i p i t a t e s i s
i m p o r t a n t a l s o i n t e r m s of m a g n e t i c p r o p e r t i e s . For
example, i n t h e c a s e when t h e d i a m e t e r of t h e
p r e c i p i t a t e i s s m a l l e r t h a n t h e t h i c k n e s s of a
m a g n e t i c domain w a l l , it i s p o s s i b l e t o p r e v e n t
d e t e r i o r a t i o n ( i n c r e a s e ) of h y s t e r e s i s l o s s c a u s e d by
p i n n i n g of domain w a l l d i s p l a c e m e n t . When t h e
a v e r a g e g r a i n s i z e of t h e p r e c i p i t a t e i s g r e a t e r t h a n
0 . 2 pm, it i s n o t p o s s i b l e t o o b t a i n t h e e f f e c t s
s u f f i c i e n t l y . Thus, t h e a v e r a g e g r a i n s i z e o f t h e
p r e c i p i t a t e i s 0 . 2 pm o r l e s s . The a v e r a g e g r a i n
s i z e i s p r e f e r a b l y 0 . 1 pm o r l e s s , i s more p r e f e r a b l y
0 . 0 5 pm o r l e s s , and i s s t i l l more p r e f e r a b l y 0 . 0 1 pm
o r l e s s .
[ 0 0 3 9 ] I n c i d e n t a l l y , t h o u g h , when t h e t h e o r e t i c a l
t h i c k n e s s of a m a g n e t i c domain w a l l o f a p u r e i r o n i s
e s t i m a t e d i n terms o f e x c h a n g e e n e r g y and a n i s o t r o p y
e n e r g y , it i s 0 . 1 pm o r s o , t h e a c t u a l t h i c k n e s s o f
t h e m a g n e t i c domain w a l l c h a n g e s a c c o r d i n g t o t h e
o r i e n t a t i o n i n which t h e m a g n e t i c domain w a l l i s
formed. F u r t h e r , a s i s a n o n - o r i e n t e d e l e c t r i c a l
s t e e l s h e e t , i n t h e c a s e when e l e m e n t s o t h e r t h a n Fe
a r e c o n t a i n e d , t h e t h i c k n e s s o f a m a g n e t i c domain
w a l l is a l s o a f f e c t e d by t h e i r t y p e s , a m o u n t s and t h e
l i k e . From t h i s v i e w p o i n t a s w e l l , it i s c o n c e i v a b l e
t h a t t h e a v e r a g e g r a i n s i z e of t h e p r e c i p i t a t e , which
i s 0.2 pm o r less, i s a p p r o p r i a t e .
[0040] When t h e a v e r a g e g r a i n s i z e o f t h e
p r e c i p i t a t e i s less t h a n 0.002 pm ( 2 nm), an e f f e c t
o f i n c r e a s i n g t h e m e c h a n i c a l s t r e n g t h is s a t u r a t e d .
F u r t h e r , it i s d i f f i c u l t t o c o n t r o l t h e a v e r a g e g r a i n
s i z e of t h e p r e c i p i t a t e i n a r a n g e o f less t h a n 0 . 0 0 2
pm. T h u s , t h e a v e r a g e g r a i n s i z e o f t h e p r e c i p i t a t e
i s 0.002 pm o r more.
[0041] F u r t h e r , a s t h e number d e n s i t y of t h e
p r e c i p i t a t e s i s h i g h e r , t h e h i g h e r s t r e n g t h c a n be
o b t a i n e d , and when t h e number d e n s i t y o f t h e
p r e c i p i t a t e s i n t h e f e r r i t e g r a i n i s l e s s t h a n 10 pm-
3 , it i s d i f f i c u l t t o o b t a i n t h e d e s i r e d s t r e n g t h .
T h e r e f o r e , t h e number d e n s i t y o f t h e p r e c i p i t a t e s i s
10 o r more. The number d e n s i t y is p r e f e r a b l y
1000 L1m-3 o r more, i s more p r e f e r a b l y 10000 p ~ n -o~r
more, i s f u r t h e r p r e f e r a b l y 100000 ) ~ r n -o~r more, and
is s t i l l more p r e f e r a b l y 1000000 pm-3 o r m o r e .
[ 0 0 4 2 ] N e x t , t h e method of m a n u f a c t u r i n g t h e nono
r i e n t e d e l e c t r i c a l s t e e l s h e e t w i l l b e e x p l a i n e d .
I n t h e embodiment, a s d e s c r i b e d a b o v e , t h e h o t
r o l l i n g o f t h e s l a b h e a t e d t o a t e m p e r a t u r e of n o t
l o w e r t h a n 1100°C n o r h i g h e r t h a n 1330°C is p e r f o r m e d
t o o b t a i n t h e h o t - r o l l e d s t e e l s h e e t . N e x t , t h e c o l d
r o l l i n g o f t h e h o t - r o l l e d s t e e l s h e e t i s p e r f o r m e d t o
o b t a i n t h e c o l d - r o l l e d s t e e l s h e e t . N e x t , t h e f i n i s h
a n n e a l i n g o f t h e c o l d - r o l l e d s t e e l s h e e t i s
p e r f o r m e d .
[ 0 0 4 3 ] I n t h e h o t r o l l i n g , by h e a t i n g , p r e c i p i t a t e s
c o n t a i n i n g T i , V, Z r , a n d / o r Nb, which a r e c o n t a i n e d
i n t h e s l a b , a r e made t o b e o n c e s o l i d - d i s s o l v e d , a n d
i n t h e f o l l o w i n g t e m p e r a t u r e - l o w e r i n g p r o c e s s ,
p r e c i p i t a t e s c o n t a i n i n g T i , V, Z r , a n d / o r Nb a r e made
t o p r e c i p i t a t e f i n e l y . When a h e a t i n g t e m p e r a t u r e i s
l o w e r t h a n llOO°C, it i s d i f f i c u l t t o s u f f i c i e n t l y
s o l i d - d i s s o l v e t h e p r e c i p i t a t e s c o n t a i n i n g T i , V, Z r ,
a n d / o r Nb. When t h e h e a t i n g t e m p e r a t u r e i s h i g h e r
t h a n 1330°C, t h e r e i s a r i s k t h a t t h e s l a b is d e f o r m e d
d u r i n g t h e h e a t i n g , o r s l a g o c c u r s . Thus, t h e
h e a t i n g t e m p e r a t u r e i s n o t l o w e r t h a n 1100°C n o r
h i g h e r t h a n 1330°C. The h e a t i n g t e m p e r a t u r e i s
p r e f e r a b l y 1150°C o r h i g h e r , and i s a l s o p r e f e r a b l y
1300°C o r l o w e r .
[ 0 0 4 4 ] I n t h e h o t r o l l i n g , f o r e x a m p l e , r o u g h
r o l l i n g and f i n i s h r o l l i n g a r e p e r f o r m e d . A f i n i s h
t e m p e r a t u r e o f t h e f i n i s h r o l l i n g ( f i n i s h i n g
t e m p e r a t u r e ) i s p r e f e r a b l y n o t lower t h a n 750°C n o r
h i g h e r t h a n 850°C, and a t e m p e r a t u r e d u r i n g c o i l i n g
a f t e r t h e f i n i s h r o l l i n g ( c o i l i n g t e m p e r a t u r e ) i s
p r e f e r a b l y 600°C o r l o w e r . I n e i t h e r c a s e , t h i s i s t o
make t h e p r e c i p i t a t e s c o n t a i n i n g T i , V , Z r , a n d / o r Nb
p r e c i p i t a t e a s f i n e l y a s p o s s i b l e .
[ 0 0 4 5 1 The t h i c k n e s s o f t h e h o t - r o l l e d s t e e l s h e e t
i s n o t l i m i t e d i n p a r t i c u l a r . However, it is n o t
e a s y t o make t h e t h i c k n e s s of t h e h o t - r o l l e d s t e e l
s h e e t t o l e s s t h a n 1 . 6 mm, which a l s o l e a d s t o a
d e c r e a s e i n p r o d u c t i v i t y . On t h e o t h e r hand, when
t h e t h i c k n e s s o f t h e h o t - r o l l e d s t e e l s h e e t i s 2 . 7
mm, it i s sometimes n e c e s s a r y t o e x c e s s i v e l y i n c r e a s e
a r e d u c t i o n r a t i o i n t h e f o l l o w i n g c o l d r o l l i n g . In
t h e c a s e when t h e r e d u c t i o n r a t i o i n t h e c o l d r o l l i n g
is h i g h e x c e s s i v e l y , a t e x t u r e of a n o n - o r i e n t e d
e l e c t r i c a l s t e e l s h e e t may sometimes d e t e r i o r a t e and
m a g n e t i c p r o p e r t i e s ( m a g n e t i c f l u x d e n s i t y and c o r e
. - l o s s ) d e t e r i o r a t e . Thus, t h e t h i c k n e s s . of t h e h o t -
r o l l e d s t e e l s h e e t is p r e f e r a b l y n o t less t h a n 1 . 6 mm
n o r more t h a n 2 . 7 mm.
[ 0 0 4 6 1 The c o l d r o l l i n g may be p e r f o r m e d o n l y one
t i m e , o r may a l s o be p e r f o r m e d two o r more t i m e s w i t h
i n t e r m e d i a t e a n n e a l i n g b e i n g i n t e r p o s e d t h e r e b e t w e e n .
The f i n a l r e d u c t i o n r a t i o i n t h e c o l d r o l l i n g is
p r e f e r a b l y n o t l e s s t h a n 60% n o r more t h a n 9 0 % . T h i s
is t o make t h e m e t a l s t r u c t u r e ( t e x t u r e ) of a nono
r i e n t e d e l e c t r i c a l s t e e l s h e e t o b t a i n e d a f t e r t h e
f i n i s h a n n e a l i n g b e t t e r t o o b t a i n a h i g h m a g n e t i c
f l u x d e n s i t y and a low c o r e l o s s . F u r t h e r , i n t h e
c a s e of t h e i n t e r m e d i a t e a n n e a l i n g b e i n g p e r f o r m e d ,
i t s t e m p e r a t u r e is p r e f e r a b l y n o t lower t h a n 900°C nor
h i g h e r t h a n 1100°C. T h i s i s t o make t h e m e t a l
s t r u c t u r e b e t t e r . The f i n a l r e d u c t i o n r a t i o i s more
p r e f e r a b l y 65% o r more, and i s a l s o more p r e f e r a b l y
82% o r l e s s .
[0047] A s o a k i n g t e m p e r a t u r e of t h e f i n i s h a n n e a l i n g
i s p r e f e r a b l y 850°C o r h i g h e r , and a s o a k i n g t i m e
p e r i o d is p r e f e r a b l y 20 s e c o n d s o r l o n g e r . T h i s i s
t o make t h e a v e r a g e g r a i n s i z e o f f e r r i t e g r a i n s i n a
n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t 10 pm o r more and
make a m e t a l s t r u c t u r e b e t t e r .
[0048] I n c i d e n t a l l y , when t h e s o a k i n g t e m p e r a t u r e of
t h e f i n i s h a n n e a l i n g i s g r e a t e r t h a n llOO°C, t h e
p r e c i p i t a t e s c o n t a i n i n g T i , V, Z r , a n d / o r Nb t h a t
have p r e c i p i t a t e d f i n e l y i n t h e c o l d - r o l l e d s t e e l
s h e e t a r e s o l i d - d i s s o l v e d t o s t r o n g l y t e n d t o
p r e c i p i t a t e t h e r e a f t e r n o t i n c r y s t a l g r a i n s b u t i n
g r a i n b o u n d a r i e s . Thus, t h e s o a k i n g t e m p e r a t u r e o f
t h e f i n i s h a n n e a l i n g i s p r e f e r a b l y 1100°C o r l o w e r .
I n c i d e n t a l l y , when t h e s o a k i n g t i m e is l o n g e r t h a n 2
m i n u t e s , a d e c r e a s e i n p r o d u c t i v i t y is s i g n i f i c a n t .
Thus, t h e s o a k i n g t i m e i s p r e f e r a b l y 2 m i n u t e s o r
s h o r t e r .
[00491 I n c i d e n t a l l y , b e f o r e p e r f o r m i n g t h e c o l d
9
r o l l i n g , a n n e a l i n g of t h e h o t - r o l l e d s t e e l s h e e t ,
namely h o t - r o l l e d s h e e t a n n e a l i n g may a l s o be
p e r f o r m e d . The a p p r o p r i a t e h o t - r o l l e d s h e e t
a n n e a l i n g i s p e r f o r m e d , t h e r e b y making a t e x t u r e of a
n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t more d e s i r a b l e
and making it p o s s i b l e t o o b t a i n a more e x c e l l e n t
m a g n e t i c f l u x d e n s i t y . I n t h e c a s e when a s o a k i n g
t e m p e r a t u r e of t h e h o t - r o l l e d s h e e t a n n e a l i n g i s
lower t h a n 850°C, and i n t h e c a s e when a s o a k i n g t i m e
p e r i o d i s s h o r t e r t h a n 30 s e c o n d s , it is d i f f i c u l t t o
make t h e t e x t u r e more d e s i r a b l e . In t h e c a s e when
t h e s o a k i n g t e m p e r a t u r e i s h i g h e r t h a n llOO°C, t h e
p r e c i p i t a t e s c o n t a i n i n g T i , V, Z r , a n d / o r Nb t h a t
have p r e c i p i t a t e d f i n e l y i n t h e h o t - r o l l e d s t e e l
s h e e t a r e s o l i d - d i s s o l v e d t o s t r o n g l y t e n d t o
p r e c i p i t a t e t h e r e a f t e r n o t i n c r y s t a l g r a i n s b u t i n
g r a i n b o u n d a r i e s . When t h e s o a k i n g t i m e p e r i o d i s
l o n g e r t h a n 5 m i n u t e s , a d e c r e a s e i n p r o d u c t i v i t y i s
s i g n i f i c a n t . Thus, i n t h e h o t - r o l l e d s h e e t
a n n e a l i n g , t h e s o a k i n g t e m p e r a t u r e i s p r e f e r a b l y n o t
l o w e r t h a n 850°C n o r h i g h e r t h a n llOO°C and t h e
s o a k i n g t i m e p e r i o d i s p r e f e r a b l y n o t s h o r t e r t h a n 30
s e c o n d s nor l o n g e r t h a n 5 m i n u t e s .
[00501 In t h i s manner, t h e n o n - o r i e n t e d e l e c t r i c a l
s t e e l s h e e t a c c o r d i n g t o t h e embodiment may be
m a n u f a c t u r e d . Then, t h e n o n - o r i e n t e d e l e c t r i c a l
s t e e l s h e e t m a n u f a c t u r e d i n t h i s manner i s p r o v i d e d
with t h e m e t a l s t r u c t u r e a s d e s c r i b e d above t o be
a b l e t o o b t a i n t h e h i g h s t r e n g t h and t h e low c o r e
l o s s . T h a t i s , t h e a b o v e - d e s c r i b e d p r e c i p i t a t e s a r e
g e n e r a t e d d u r i n g t h e h o t r o l l i n g , and
r e c r y s t a l l i z a t i o n i s c a u s e d and t h e a b o v e - d e s c r i b e d
f e r r i t e p h a s e i s g e n e r a t e d d u r i n g t h e f i n i s h
a n n e a l i n g . I n c i d e n t a l l y , an i n s u l a t i n g c o a t i n g f i l m
may a l s o be formed a c c o r d i n g t o need a f t e r t h e f i n i s h
a n n e a l i n g .
[0051] Next, t h e r e w i l l be e x p l a i n e d a l a m i n a t e f o r
a motor i r o n c o r e c o n s t i t u t e d w i t h t h e n o n - o r i e n t e d
e l e c t r i c a l s t e e l s h e e t s a c c o r d i n g t o t h e embodiment.
[0052] The n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s
a c c o r d i n g t o t h e embodiment a r e i n c l u d e d i n t h e
l a m i n a t e f o r t h e motor i r o n c o r e . The l a m i n a t e f o r
t h e motor i r o n c o r e may be o b t a i n e d i n a manner t h a t
t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s a r e formed
i n t o a d e s i r e d s h a p e by p u n c h i n g o r t h e l i k e , and a r e
l a m i n a t e d t o be f i x e d by c a u l k i n g o r t h e l i k e , f o r
example. S i n c e t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l
s h e e t s a c c o r d i n g t o t h e embodiment a r e i n c l u d e d , a
c o r e l o s s of t h e l a m i n a t e f o r t h e motor i r o n c o r e i s
low and m e c h a n i c a l s t r e n g t h of t h e l a m i n a t e i s h i g h .
[0053] The l a m i n a t e f o r t h e m o t o r i r o n c o r e may be
c o m p l e t e d a t t h e t i m e when t h e f i x a t i o n a s d e s c r i b e d
above is f i n i s h e d . F u r t h e r , a n n e a l i n g may be
p e r f o r m e d a f t e r t h e a b o v e - d e s c r i b e d f i x a t i o n and
b e f o r e c o m p l e t i n g t h e l a m i n a t e . The a n n e a l i n g may be
p e r f o r m e d under a c o n d i t i o n i n which a s o a k i n g
t e m p e r a t u r e i s n o t l o w e r t h a n 400°C n o r h i g h e r t h a n
800°C, a s o a k i n g t i m e p e r i o d i s n o t s h o r t e r t h a n 2
m i n u t e s n o r l o n g e r t h a n 10 h o u r s , and a n a v e r a g e
c o o l i n g r a t e from t h e s o a k i n g t e m p e r a t u r e t o 300°C i s
n o t l e s s t h a n O.OOOl°C n o r more t h a n O.l°C, and t h e
l a m i n a t e f o r a motor i r o n c o r e may be c o m p l e t e d a f t e r
f i n i s h i n g t h e a n n e a l i n g . P r e c i p i t a t e s a r e
p r e c i p i t a t e d t h r o u g h t h e a n n e a l i n g , t h e r e b y making it
p o s s i b l e t o f u r t h e r i m p r o v e t h e s t r e n g t h .
[ 0 0 5 4 ] I n t h e c a s e when t h e s o a k i n g t e m p e r a t u r e o f
t h e a n n e a l i n g i s l o w e r t h a n 400°C, and i n t h e c a s e
when t h e s o a k i n g t i m e p e r i o d i s s h o r t e r t h a n 2
m i n u t e s , i t i s d i f f i c u l t t o make t h e p r e c i p i t a t e s
p r e c i p i t a t e s u f f i c i e n t l y . I n t h e c a s e when t h e
s o a k i n g t e m p e r a t u r e is h i g h e r t h a n 800°C, and i n t h e
c a s e when t h e s o a k i n g t i m e p e r i o d is l o n g e r t h a n 10
h o u r s , e n e r g y c o n s u m p t i o n i s i n c r e a s e d , o r a s s o c i a t e d
f a c i l i t i e s a r e l i k e l y t o be damaged, a n d a n i n c r e a s e
i n c o s t i s s i g n i f i c a n t . F u r t h e r , t h e p r e c i p i t a t e s
may s o m e t i m e s p r e c i p i t a t e c - o a r s e l y t o t h e r e b y make it
d i f f i c u l t t o i n c r e a s e t h e s t r e n g t h s u f f i c i e n t l y .
Thus, t h e s o a k i n g t e m p e r a t u r e i s p r e f e r a b l y n o t l o w e r
t h a n 400°C n o r h i g h e r t h a n 800°C, and t h e s o a k i n g t i m e
p e r i o d is p r e f e r a b l y n o t s h o r t e r t h a n 2 m i n u t e s n o r
l o n g e r t h a n 1 0 h o u r s . F u r t h e r , t h e s o a k i n g
t e m p e r a t u r e i s more p r e f e r a b l y 500°C o r h i g h e r , and
t h e s o a k i n g t i m e p e r i o d i s more p r e f e r a b l y 10 m i n u t e s
o r l o n g e r . When t h e a v e r a g e c o o l i n g r a t e from t h e
soaking temperature to 300°C is less than
O.OOOl°C/sec, carbide is likely to precipitate
coarsely. When the average cooling rate is greater
than O.l°C/sec, it is difficult to make the
precipitates precipitate sufficiently. Thus, the
average cooling rate from the soaking temperature to
300°C is preferably not less than O.OOOl°C/sec nor
more than 0. 1°C/sec.
EXAMPLE
[0055] Next, there will be explained experiments
conducted by the present inventors. Conditions and
so on in these experiments are examples employed for
confirming the applicability and effects of the
present invention, and the present invention is not
limited to these examples.
[0056] (Experimental example 1)
First, steels having various compositions listed
in Table 1 were melted by vacuum melting. Then,
obtained slabs were each heated at 1250°C for 1 hour.
Thereafter, hot rolling of each of the slabs heated
to a temperature of 1250°C was performed to obtain
hot-rolled steel sheets. The thickness of each of
the hot-rolled steel sheets (hot-rolled sheets) was
2.0 rnm. Subsequently, pickling of each of the hotrolled
steel sheets was performed, and cold rolling
of each of the hot-rolled steel sheets was performed
to obtain cold-rolled steel sheets. The thickness of
each of the cold-rolled steel sheets (cold-rolled
s h e e t s ) was 0 . 3 5 mm. Then, f i n i s h a n n e a l i n g of e a c h
of t h e c o l d - r o l l e d s t e e l s h e e t s was p e r f o r m e d . A
s o a k i n g t e m p e r a t u r e was 1000°C and a s o a k i n g t i m e
p e r i o d was 30 s e c o n d s i n t h e f i n i s h a n n e a l i n g . I n
t h i s manner, v a r i o u s n o n - o r i e n t e d e l e c t r i c a l s t e e l
s h e e t s were m a n u f a c t u r e d . Then, a m e t a l s t r u c t u r e o f
e a c h of t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s was
o b s e r v e d . I n t h e o b s e r v a t i o n of t h e m e t a l s t r u c t u r e ,
f o r example, measurement of a g r a i n s i z e ( J I S G 0552)
and o b s e r v a t i o n of p r e c i p i t a t e s were p e r f o r m e d .
F u r t h e r , a JIS No. 5 t e s t p i e c e was c u t o u t from e a c h
of t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s , and i t s
m e c h a n i c a l p r o p e r t y was m e a s u r e d . F u r t h e r , a t e s t
p i e c e of 55 mm x 55 mm was c u t o u t from each of t h e
n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s , and i t s
m a g n e t i c p r o p e r t y w e r e measured by a s i n g l e s h e e t
m a g n e t i c p r o p e r t y measurement method ( J I S C 2 5 5 6 ) .
A s t h e m a g n e t i c p r o p e r t y , a c o r e l o s s under a
c o n d i t i o n of a f r e q u e n c y b e i n g 400 Hz and a maximum
m a g n e t i c f l u x d e n s i t y b e i n g 1 . 0 T (WlOJ400) was
m e a s u r e d . F u r t h e r , a c o r e l o s s (W10/400) was
measured also a f t e r an a g i n g t r e a t m e n t a t 200°C f o r 1
day i n o r d e r t o o b s e r v e an e f f e c t of m a g n e t i c a g i n g .
T h a t i s , w i t h r e s p e c t t o e a c h of t h e n o n - o r i e n t e d
e l e c t r i c a l s t e e l s h e e t s , t h e c o r e l o s s (W10/400) was
measured b e f o r e and a f t e r t h e a g i n g t r e a t m e n t . These
r e s u l t s a r e l i s t e d i n T a b l e 2 .
[0057] [ T a b l e 11
TABLE 1
[ 0 0 5 8 ] [Table 21
TABLE 2
REMARKS
[ 0 0 5 9 ] As l i s t e d i n T a b l e 2, i n c o n d i t i o n s No. C 1 t o
No. C19 e a c h f a l l i n g w i t h i n t h e r a n g e o f t h e p r e s e n t
i n v e n t i o n , it was p o s s i b l e t o o b t a i n a t e n s i l e
s t r e n g t h o f 550 MPa o r more and a c o r e l o s s (W10/400)
o f 35 W/kg o r l e s s . On t h e o t h e r h a n d , i n c o n d i t i o n s
No. Dl t o No. D8 e a c h f a l l i n g o u t s i d e t h e r a n g e o f
t h e p r e s e n t i n v e n t i o n , it was d i f f i c u l t t o a c h i e v e
t h e t e n s i l e s t r e n g t h and t h e c o r e l o s s .
[ 0 0 6 0 ] ( E x p e r i m e n t a l e x a m p l e 2 )
F i r s t , s l a b s made o f s t e e l s No. A l l a n d No. A 1 7
l i s t e d i n T a b l e 1 were h e a t e d a t t e m p e r a t u r e s l i s t e d
i n T a b l e 3 f o r 1 h o u r . Then, h o t r o l l i n g o f e a c h o f
t h e s l a b s h e a t e d t o t h e t e m p e r a t u r e s l i s t e d i n T a b l e
3 was p e r f o r m e d t o o b t a i n h o t - r o l l e d s t e e l s h e e t s .
The t h i c k n e s s o f e a c h o f t h e h o t - r o l l e d s t e e l s h e e t s
was 2.0 mm. T h e r e a f t e r , a n n e a l i n g ( h o t - r o l l e d s h e e t
a n n e a l i n g ) o f one ( c o n d i t i o n No. E 4 ) of t h e h o t -
r o l l e d s t e e l s h e e t s was p e r f o r m e d u n d e r t h e c o n d i t i o n
l i s t e d i n T a b l e 3 . S u b s e q u e n t l y , p i c k l i n g o f e a c h of
t h e h o t - r o l l e d s t e e l s h e e t s was p e r f o r m e d , and c o l d -
r o l l i n g o f each o f t h e h o t - r o l l e d s t e e l s h e e t s was
p e r f o r m e d t o o b t a i n c o l d - r o l l e d s t e e l s h e e t s . The
t h i c k n e s s o f e a c h of t h e c o l d - r o l l e d s t e e l s h e e t s was
0 . 3 5 mm. Then, f i n i s h a n n e a l i n g o f e a c h o f t h e c o l d -
r o l l e d s t e e l s h e e t s was p e r f o r m e d . A s o a k i n g
t e m p e r a t u r e was 1000°C a n d a s o a k i n g t i m e p e r i o d was
30 s e c o n d s i n t h e f i n i s h a n n e a l i n g . I n t h i s m a n n e r ,
v a r i o u s n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s were
m a n u f a c t u r e d . T h e r e a f t e r , w i t h r e s p e c t t o e a c h of
t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s , t h e
e v a l u a t i o n s s i m i l a r t o t h o s e of E x p e r i m e n t a l example
1 were p e r f o r m e d . These r e s u l t s a r e a l s o l i s t e d i n
T a b l e 3.
[ 0 0 6 1 ] [ T a b l e 31
TABLE 3
REMARKS
MECHANICAL
PROPERTY
TENSILE
STRENGTH
(MP~)
I 560
%
8 ' 0
E l
METALSTRUCTURE
1250
1050
IS40
MAGNETIC
PROPERTIES
CRYSTALUZED
NONSTRUCTURE
AREA RATIO
(%)
0
-
-
-
HOT-ROLLED
€8
F1
F2
1200
1250
1250
1150
A a
6
A l l
BEFORE
AGING
TREATMENT
W10/400
(W/kn)
21
34
27
25 . 27
SHEET
SOAKING
TEMPERATURE
("C)
-
A17
A l l
A11
SUB
HFATING
HEATING
TEMPERATURE
PC)
1150
AFTER
AGING
TREATMENT
W10/400
(w/kd
21
33
28
25
26
0
o
0
0
AVERAGE
GRAIN
DlAMETER
(urn)
165
ANNEAUNG
SOAKNO pz$, (wc)
-- -
9-50
15
32
33
- -
8-0
PRECIPITATE
0.015
1.1
0.01
AVERAGE
GRAIN
DIAMETER
(urn)
0.15
32
210
9
83000
330
8100
-
-
-
0.01
0.04
0.05
Tic, NbC. Cu
NbC
NbC
0
0
0
NUMBER
bm-5)
250
680
490
640
TYPES OF MAIN
PRECIPITATES
NbC
84000
47000
38000
, 95
33
21
38
32
21
38
NbC 1 880
N ~ C I aoo
NbC 1 500
0.007 820000
PRECIPITATES WERE
LARGE. AND
MSETCRHEANNGICTHA L
WAS POOR.
FERRITE GRAINS WERE
SMALL AND
CORE LOSS WAS HIGH.
, Tic. NbC, Cu 710
[00621 As listed in Table 3, in conditions No, El to
No. E6 each falling within the range of the present
invention, it was possible to obtain a tensile
strength of 550 MPa or more and a core loss (W10/400)
of 35 W/kg or less. On the other hand, in conditions
No. F1 and No. F2 each falling outside the range of
the present invention, it was difficult to achieve
the tensile strength and the core loss.
[00631 (Experimental example 3)
First, slabs made of steels No. All and No. A17
listed in Table 1 were each heated for 1 hour. At
that time, a slab heating temperature of the steel
No. All was 1250°C, and the slab heating temperature
of the steel No. -A17 was 1150°C. Then, hot rolling of
each of the slabs heated to 1250°C or 1150°C was
performed to obtain hot-rolled steel sheets. The
thickness of each of the hot-rolled steel sheets was
2.0 mm. Thereafter, pickling of each of the hotrolled
steel sheets was performed, and cold rolling
of each of the hot-rolled steel sheets was performed
to obtain cold-rolled steel sheets. The thickness of
each of the cold-rolled steel sheets was 0.35 mm.
Subsequently, finish annealing of each of the coldrolled
steel sheets was performed. A soaking
temperature was 1000°C and a soaking time period was
30 seconds in the finish annealing. Then, an
insulating film was formed on the surface of each of
the cold-rolled steel sheets obtained after the
f i n i s h a n n e a l i n g . I n t h i s manner, v a r i o u s nono
r i e n t e d e l e c t r i c a l s t e e l s h e e t s were m a n u f a c t u r e d .
[00641 T h e r e a f t e r , 30 s t e e l s h e e t s e a c h h a v i n g a
s i z e i n a r o l l i n g d i r e c t i o n of 300 mm and a s i z e i n a
d i r e c t i o n p e r p e n d i c u l a r t o t h e r o l l i n g d i r e c t i o n of
60 mm were punched out from e a c h of t h e n o n - o r i e n t e d
e l e c t r i c a l s t e e l s h e e t s . The s t e e l s h e e t h a v i n g such
a s h a p e and s i z e i s sometimes u s e d f o r an a c t u a l
motor c o r e . Then, t h e 30 s t e e l s h e e t s were l a m i n a t e d
t o one a n o t h e r t o o b t a i n a l a m i n a t e . S u b s e q u e n t l y ,
a n n e a l i n g of e a c h of t h e l a m i n a t e s was p e r f o r m e d
u n d e r t h e c o n d i t i o n l i s t e d i n T a b l e 4 . Then, a s t e e l
s h e e t f o r a test was e x t r a c t e d from e a c h of t h e
l a m i n a t e s , and w i t h r e s p e c t t o t h e s t e e l s h e e t , t h e
e v , a l u a t i o n s s i m i l a r t o t h o s e o f E x p e r i m e n t a l example
1 were p e r f o r m e d . That is, t h e e v a l u a t i o n i n t e n d e d
f o r a l a m i n a t e u s e d f o r a motor c o r e was p e r f o r m e d .
These r e s u l t s a r e a l s o l i s t e d i n Table 4 . Here, o n e s
w i t h t h e a n n e a l i n g c o n d i t i o n d e v i a t i n g from t h e
a b o v e - d e s c r i b e d f a v o r a b l e c o n d i t i o n were e a c h set a s
a c o m p a r a t i v e e x a m p l e .
[0065] [ T a b l e 4 1
TABLE 4
[ 0 0 6 6 ] As listed in Table 4, in conditions No. G 1 to
No. G7 in which the favorable annealing was
performed, it was possible to sufficiently improve
the tensile strength. On the other hand, in
conditions No. H1 to No. H6 with the annealing
condition deviating from the favorable range, it was
not possible to sufficiently improve the tensile
strength, the productivity was low, or the core loss
was high.
[ 0 0 6 7 ] It should be noted that the above-described
embodiment merely illustrates a concrete example of
implementing the present invention, and the technical
scope of the present invention is not to be construed
in a restrictive manner by the embodiment. That is,
the present invention may be implemented in various
forms without departing from the technical spirit or
main features thereof.
INDUSTRIAL APPLICABILITY
[0068] The present invention may be utilized in an
industry of manufacturing electrical steelr- sheets and
in an industry of utilizing electrical steel sheets
such as motors, for example.

CLAIMS
[Claim 11 A n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t
c o n t a i n i n g :
i n mass%,
C: g r e a t e r t h a n 0.01% and 0.05% o r l e s s ;
S i : n o t l e s s t h a n 2.0% n o r more t h a n 4 . 0 % ;
Mn: n o t l e s s t h a n 0.05% n o r more t h a n 0 . 5 % ;
A l : n o t less t h a n 0.01% n o r more t h a n 3 . 0 % ; and
a t l e a s t one s e l e c t e d from t h e group c o n s i s t i n g
of T i , V, Z r , and Nb,
a b a l a n c e b e i n g composed of Fe and i n e v i t a b l e
i m p u r i t i e s ,
w h e r e i n
when c o n t e n t s of T i , V, Z r , N b , and C (mass%) a r e
r e p r e s e n t e d a s [ T i ] , [V], [ Z r ] , [Nb], and [ C ]
r e s p e c t i v e l y , a v a l u e of a p a r a m e t e r Q r e p r e s e n t e d by
"Q = ( [ T i ] / 4 8 + [ V ] / 5 1 + [ Z r ] / 9 1 + [ N b ] / 9 3 ) / ( [ C ] / 1 2 ) "
is n o t l e s s t h a n 0 . 9 nor more t h a n 1.1,
a m a t r i x of a m e t a l s t r u c t u r e is a f e r r i t e p h a s e ,
t h e m e t a l s t r u c t u r e d o e s n o t c o m p r i s e a non=
r e c r y s t a l l i z e d s t r u c t u r e ,
a n a v e r a g e g r a i n s i z e of f e r r i t e g r a i n s
c o n s t i t u t i n g t h e f e r r i t e p h a s e i s n o t l e s s t h a n 10 pm
nor more t h a n 200 pm,
a p r e c i p i t a t e c o n t a i n i n g a t l e a s t one s e l e c t e d
from t h e g r o u p c o n s i s t i n g of T i , V , Z r , and N b e x i s t s
with a d e n s i t y of 1 0 o r more i n t h e f e r r i t e
grain, a n d
an a v e r a g e g r a i n s i z e of t h e p r e c i p i t a t e i s n o t
less t h a n 0.002 ym n o r more t h a n 0 . 2 pm.
[Claim 23 The n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t
a c c o r d i n g t o c l a i m 1, f u r t h e r c o n t a i n i n g :
i n mass%, a-t l e a s t one s e l e c t e d from t h e g r o u p
c o n s i s t i n g o f
N : n o t l e s s t h a n 0 . 0 0 1 % nor more t h a n 0 . 0 0 4 % ;
Cu: n o t less t h a n 0 . 5 % nor more t h a n 1.5%; a n d
Sn: n o t less t h a n 0.05% nor more t h a n 0 . 5 % .
[Claim 31 The n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t
a c c o r d i n g t o c l a i m 1, w h e r e i n t h e p r e c i p i t a t e is a t
l e a s t one s e l e c t e d from t h e group c o n s i s t i n g of
c a r b i d e , n i t r i d e , and c a r b o n i t r i d e .
[Claim 4 1 The n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t
a c c o r d i n g t o c l a i m 2 , w h e r e i n t h e p r e c i p i t a t e is a t
l e a s t one s e l e c t e d from t h e g r o u p c o n s i s t i n g of
c a r b i d e , n i t r i d e , and c a r b o n i t r i d e .
[Claim 51 A method of m a n u f a c t u r i n g a n o n - o r i e n t e d
e l e c t r i c a l s t e e l s h e e t c o m p r i s i n g :
p e r f o r m i n g h o t r o l l i n g of a s l a b h e a t e d t o a
t e m p e r a t u r e o f n o t l o w e r t h a n l l O O ° C n o r h i g h e r t h a n
1330°C t o o b t a i n a h o t - r o l l e d s t e e l s h e e t ;
p e r f o r m i n g c o l d r o l l i n g of t h e h o t - r o l l e d steel
s h e e t t o o b t a i n a c o l d - r o l l e d s t e e l s h e e t ; and
p e r f o r m i n g f i n i s h a n n e a l i n g of t h e c o l d - r o l l e d
s t e e l s h e e t a t a t e m p e r a t u r e of n o t l o w e r t h a n 850°C
nor h i g h e r t h a n llOO°C,
w h e r e i n
the slab contains:
in mass%,
C: greater than 0.01% and 0.05% or less;
Si: not less than 2.0% nor more than 4.0%;
Mn: not less than 0.05% nor more than 0.5%;
Al: not less than 0.01% nor more than 3.0%; and
at least one selected from the group consisting
of Ti, V, Zr, and Nb,
a balance being composed of Fe and inevitable
impurities, and
when contents of Ti, V, Zr, Nb, and C (mass%) are
represented as [Ti], [ V ] , [Zr], [Nb], and [C]
respectively, a value of a parameter Q represented by
"Q = ([Ti] /48 + [V]/51 + [Zr] /91 + [Nb]/93) / ([C] / 1 2 ) "
is not less than 0.9 nor more than 1.1.
[Claim 61 The method of manufacturing the nonoriented
electrical steel sheet according ,to claim 5,
wherein the slab further contains:
in mass%, at least one selected from the group
consisting of
N: not less than 0.001% nor more than 0.004%;
Cu: not less than 0.5% nor more than 1.5%; and
Sn: not less than 0.05% nor more than 0.5%.
[Claim 71 The method of manufacturing the nonoriented
electrical steel sheet according to claim 5,
further comprising, before the performing cold
rolling, performing hot-rolled sheet annealing of the
hot-rolled steel sheet.
[Claim 81 The method of m a n u f a c t u r i n g t h e nono
r i e n t e d e l e c t r i c a l s t e e l s h e e t a c c o r d i n g t o c l a i m 6 ,
f u r t h e r c o m p r i s i n g , b e f o r e t h e p e r f o r m i n g c o l d
r o l l i n g , p e r f o r m i n g h o t - r o l l e d s h e e t a n n e a l i n g of t h e
h o t - r o l l e d s t e e l s h e e t .
[Claim 93 A l a m i n a t e f o r a motor i r o n c o r e
c o m p r i s i n g :
n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s l a m i n a t e d t o
one a n o t h e r ,
w h e r e i n
e a c h of t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s
c o n t a i n s :
i n mass%,
C: g r e a t e r t h a n 0.01% and 0.05% o r l e s s ;
S i : n o t l e s s t h a n 2 . 0 % n o r more t h a n 4 . 0 % ;
Mn: n o t l e s s t h a n 0.05% n o r more t h a n 0 . 5 % ;
A l : n o t l e s s t h a n 0.01% n o r more t h a n 3 . 0 % ; a n d
a t l e a s t one s e l e c t e d from t h e g r o u p c o n s i s t i n g
of T i , V, Z r , and Nb,
a b a l a n c e b e i n g composed of Fe and i n e v i t a b l e
i m p u r i t i e s ,
when c o n t e n t s of T i , V, Z r , Nb, and C (mass%) a r e
r e p r e s e n t e d a s [ T i ] , [V], [ Z r ] , [Nb], and [ C ]
r e s p e c t i v e l y , a v a l u e of a p a r a m e t e r Q r e p r e s e n t e d by
"Q = ( [ T i ] / 4 8 + [V]/51 + [ Z r ] / 9 1 + [ N b ] / 9 3 ) / ( [ C ] / 1 2 ) "
i s n o t l e s s t h a n 0 . 9 n o r more t h a n 1 . 1 ,
a m a c r i x o f a m e t a l s t r u c t u r e i s a f e r r i t e p h a s e ,
t h e m e t a l s t r u c t u r e d o e s n o t c o m p r i s e a nonr
e c r y s t a l l i z e d s t r u c t u r e ,
an a v e r a g e g r a i n s i z e o f f e r r i t e g r a i n s
c o n s t i t u t i n g t h e f e r r i t e p h a s e i s n o t less t h a n 10 pm
n o r more t h a n 200 pm,
a p r e c i p i t a t e c o n t a i n i n g a t l e a s t one s e l e c t e d
from t h e g r o u p c o n s i s t i n g o f T i , V, Z r , and Nb e x i s t s
w i t h a d e n s i t y o f 1 0 pm-3 o r more i n t h e f e r r i t e
g r a i n , and
a n a v e r a g e g r a i n s i z e o f t h e p r e c i p i t a t e i s n o t
less t h a n 0 . 0 0 2 pm n o r more t h a n 0 . 2 pm.
[ C l a i m 101 The l a m i n a t e f o r t h e m o t o r i r o n c o r e
a c c o r d i n g t o c l a i m 9, w h e r e i n e a c h o f t h e nono
r i e n t e d e l e c t r i c a l s t e e l s h e e t s f u r t h e r c o n t a i n s :
i n mass%, a t l e a s t one s e l e c t e d from t h e g r o u p
c o n s i s t i n g o f
N : n o t less t h a n 0.001% n o r more t h a n 0 . 0 0 4 % ;
Cu: n o t l e s s t h a n 0.5% n o r more t h a n 1 . 5 % ; and
Sn: n o t l e s s t h a n 0.05% n o r more t h a n 0 . 5 % .
[ C l a i m 111 The l a m i n a t e f o r t h e m o t o r i r o n c o r e
a c c o r d i n g t o c l a i m 9, w h e r e i n t h e p r e c i p i t a t e i s a t
l e a s t one selected from t h e g r o u p c o n s i s t i n g of
c a r b i d e , n i t r i d e , a n d c a r b o n i t r i d e .
[ C l a i m 121 The l a m i n a t e f o r t h e m o t o r i r o n c o r e
a c c o r d i n g t o c l a i m 1 0 , w h e r e i n t h e p r e c i p i t a t e is a t
l e a s t one s e l e c t e d from t h e g r o u p c o n s i s t i n g o f
c a r b i d e , n i t r i d e , a n d c a r b o n i t r i d e .
[ C l a i m 131 A method o f m a n u f a c t u r i n g a l a m i n a t e f o r
a m o t o r i r o n c o r e c o m p r i s i n g :
l a m i n a t i n g n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s
t o one a n o t h e r t o o b t a i n a l a m i n a t e ; and
a n n e a l i n g t h e l a m i n a t e u n d e r a c o n d i t i o n i n which
a s o a k i n g t e m p e r a t u r e i s n o t l o w e r t h a n 400°C n o r
h i g h e r t h a n 800°C, a s o a k i n g t i m e p e r i o d i s n o t
s h o r t e r t h a n 2 m i n u t e s n o r l o n g e r t h a n 10 h o u r s , and
an a v e r a g e c o o l i n g r a t e from the s o a k i n g t e m p e r a t u r e
t o 300°C i s n o t less t h a n O.OOOl°C/sec n o r more t h a n
0. 1 ° C / s e c ,
w h e r e i n
e a c h o f t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l s h e e t s
c o n t a i n s :
i n mass%,
C: g r e a t e r t h a n 0.01% and 0 . 0 5 % o r less;
S i : n o t less t h a n 2 . 0 % n o r more t h a n 4 . 0 % ;
Mn: n o t less t h a n 0 . 0 5 % n o r more t h a n 0 . 5 % ;
A l : n o t l e s s t h a n 0.01% n o r more t h a n 3 . 0 % ; and
a t l e a s t o n e s e l e c t e d from t h e g r o u p c o n s i s t i n g
of T i , V, Z r , and Nb,
a b a l a n c e b e i n g composed o f Fe and i n e v i t a b l e
i m p u r i t i e s ,
when c o n t e n t s of T i , V, Z r , N b , and C ( m a s s % ) a r e
r e p r e s e n t e d as [ T i ] , [ V ] , [ Z r ] , [ N b ] , and [C]
r e s p e c t i v e l y , a v a l u e o f a p a r a m e t e r Q r e p r e s e n t e d by
"Q = ( [ T i l / 4 8 + [ V ] / 5 1 + [ Z r ] / 9 1 + [Nbl / 9 3 ) / ( [ C ] / 1 2 ) "
i s n o t less t h a n 0 . 9 n o r more t h a n 1.1,
a m a t r i x o f a m e t a l s t r u c t u r e i s a f e r r i t e p h a s e ,
t h e m e t a l s t r u c t u r e d o e s n o t c o m p r i s e a nonr
e c r y s t a l l i z e d s t r u c t u r e ,
an a v e r a g e g r a i n s i z e o f f e r r i t e g r a i n s
c o n s t i t u t i n g t h e f e r r i t e p h a s e i s n o t less t h a n 10 pm
nor more t h a n 200 pm,
a p r e c i p i t a t e c o n t a i n i n g a t l e a s t one s e l e c t e d
from t h e g r o u p c o n s i s t i n g of T i , V , Z r , and Nb e x i s t s
w i t h a d e n s i t y of 1 0 p m - ~ o r more i n t h e f e r r i t e g r a i n ,
and
an a v e r a g e g r a i n s i z e of t h e p r e c i p i t a t e i s n o t
less t h a n 0.002 pm n o r more t h a n 0 . 2 pm.
[ C l a i m 1 4 ] The method of m a n u f a c t u r i n g t h e l a m i n a t e
f o r t h e motor i r o n c o r e a c c o r d i n g t o c l a i m 1 3 ,
w h e r e i n e a c h of t h e n o n - o r i e n t e d e l e c t r i c a l s t e e l
s h e e t s f u r t h e r c o n t a i n s :
i n mass%, a t l e a s t one s e l e c t e d from t h e group
c o n s i s t i n g of
N : n o t less t h a n 0.001% n o r more t h a n 0 . 0 0 4 % ;
Cu: n o t l e s s t h a n 0.5% n o r more t h a n 1 . 5 % ; and
Sn: n o t l e s s t h a n 0.05% n o r more t h a n 0 . 5 % .
[Claim 15] The method o f m a n u f a c t u r i n g t h e l a m i n a t e
f o r t h e motor i r o n c o r e a c c o r d i n g t o c l a i m 1 3 ,
w h e r e i n t h e p r e c i p i t a t e is a t l e a s t one s e l e c t e d from
t h e group c o n s i s t i n g o f c a r b i d e , n i t r i d e , and
c a r b o n i t r i d e .
[Claim 16] The method o f m a n u f a c t u r i n g t h e l a m i n a t e
f o r t h e motor i r o n c o r e a c c o r d i n g t o c l a i m 1 4 ,
w h e r e i n t h e p r e c i p i t a t e is a t l e a s t one s e l e c t e d from
t h e group c o n s i s t i n g of c a r b i d e , n i t r i d e , and
carbonitride.