CA2010586A1 - Method of making non-oriented magnetic steel strips - Google Patents
Method of making non-oriented magnetic steel stripsInfo
- Publication number
- CA2010586A1 CA2010586A1 CA002010586A CA2010586A CA2010586A1 CA 2010586 A1 CA2010586 A1 CA 2010586A1 CA 002010586 A CA002010586 A CA 002010586A CA 2010586 A CA2010586 A CA 2010586A CA 2010586 A1 CA2010586 A1 CA 2010586A1
- Authority
- CA
- Canada
- Prior art keywords
- slab
- temperature
- rolling
- hot
- annealing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Manufacturing Of Steel Electrode Plates (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
For enabling to manufacturing the non-oriented steel strips, by HDR, the invention is to decrease the amounts of AlN and MnS
which precipitate on the way of HDR to such a level that they do not affect the magnetic properties by regulating the Al and S
contents, and further to have unavoidable precipitating nitrides precipitate as coarse BN. In the invention, in regard to the steel composition, the amounts of C, Si and P are not only regul-ated, but also the amounts of Mn, Al, S and N are regulated from the above standpoint, and a proper amount of B is added if required.
In addition, in regard to treatment conditions, in order to secure necessary finishing and coiling temperatures, the lower limit of the slab temperature at the starting time of HDR is specified.
Moreover, to secure precipitation of BN and recrystallization of a ferrite structure, the lower limits of the finishing and coiling temperatures are specified. Furthermore, to secure the magnetic properties after cold rolling, the strips are finally continuously annealed at the determined temperature.
For enabling to manufacturing the non-oriented steel strips, by HDR, the invention is to decrease the amounts of AlN and MnS
which precipitate on the way of HDR to such a level that they do not affect the magnetic properties by regulating the Al and S
contents, and further to have unavoidable precipitating nitrides precipitate as coarse BN. In the invention, in regard to the steel composition, the amounts of C, Si and P are not only regul-ated, but also the amounts of Mn, Al, S and N are regulated from the above standpoint, and a proper amount of B is added if required.
In addition, in regard to treatment conditions, in order to secure necessary finishing and coiling temperatures, the lower limit of the slab temperature at the starting time of HDR is specified.
Moreover, to secure precipitation of BN and recrystallization of a ferrite structure, the lower limits of the finishing and coiling temperatures are specified. Furthermore, to secure the magnetic properties after cold rolling, the strips are finally continuously annealed at the determined temperature.
Description
2 ~
A METHOD OF MAKING NON-ORIENTED MAGNETIC STEEL STRIPS
TECHNICAL FIELD
The present invention relates to a method of making non-oriented magnetic steel strips through a hot direct rolling (called as "HDR" hereinafter).
Generally, HDR means, strictly speaking, a rolling method that a cast slab is directly hot-rolled without heating. But the explanation of the invention also includes in HDR in a broad sense such a process that the cast slab is reheated before a temperature goes down remarkably and is hot-rolled (hot slab -reheating - rolling).
BACKGROUND OF THE INVENTION
As important factors governing properties of magnetic steel strips, there are amounts, sizes, morphology and distribution of 15AlN and MnS which precipitate in steel. They do not only influ- i -ence the magnetic properties of final products but also play important roles for the formation of the microstructure of the steel strips during a series of processing.
In a case of grain oriented silicon steel strips, the pre-20cipitates such as AlN and MnS are effectively utilized as inhibi-tors which control a secondary recrystallization. However, with respect to the non-oriented silicon steel strips, there have been disclosed technologies to make the precipitates harmless, as follows:-251. The slab is heated at low temperature so as to check re-solution of AlN or MnS (e.g. Patent Publication No.50-35885). -2, The amounts of S and O are decreased which produce fine .
:, . ,, , , : . :
2()~ 5~
precipitates of non-metallic inclusions (e.g. Patent Publication No.56-22931).
A METHOD OF MAKING NON-ORIENTED MAGNETIC STEEL STRIPS
TECHNICAL FIELD
The present invention relates to a method of making non-oriented magnetic steel strips through a hot direct rolling (called as "HDR" hereinafter).
Generally, HDR means, strictly speaking, a rolling method that a cast slab is directly hot-rolled without heating. But the explanation of the invention also includes in HDR in a broad sense such a process that the cast slab is reheated before a temperature goes down remarkably and is hot-rolled (hot slab -reheating - rolling).
BACKGROUND OF THE INVENTION
As important factors governing properties of magnetic steel strips, there are amounts, sizes, morphology and distribution of 15AlN and MnS which precipitate in steel. They do not only influ- i -ence the magnetic properties of final products but also play important roles for the formation of the microstructure of the steel strips during a series of processing.
In a case of grain oriented silicon steel strips, the pre-20cipitates such as AlN and MnS are effectively utilized as inhibi-tors which control a secondary recrystallization. However, with respect to the non-oriented silicon steel strips, there have been disclosed technologies to make the precipitates harmless, as follows:-251. The slab is heated at low temperature so as to check re-solution of AlN or MnS (e.g. Patent Publication No.50-35885). -2, The amounts of S and O are decreased which produce fine .
:, . ,, , , : . :
2()~ 5~
precipitates of non-metallic inclusions (e.g. Patent Publication No.56-22931).
3. Ca and REM are added to control morphology of sulfide inclu-sions (e.g. Patent Publications No.58-17248 and No.58-17249).
4. The steel strip is coiled at ultra high temperature after hot rolling so as to cause a self-annealing thereof, so that AlN
is coarsened by self-annealing effect (Patent Publication No.57-43132).
Most of these technologies are based on the premise of the conventional processes which consist of slab reheating and hot rolling. However, taking it into consideration to employ the direct rolling regarded as promising in terms of energy- and process-savings, the above technologies alone are insufficient to obtain the excellent magnetic properties, because in the direct rolling, AlN or MnS finely precipitate in steel during the hot rolling process.
Therefore from the viewpoint of solving the above problems, as a method of coarsening AlN in HDR, technologies have been pro-posed to coarsen AlN by briefly heating the slab on the way of 20 HDR as taught in Patent Publications No.56-18045, No.56-33451 and Laid-Open No.58-123825. However, these techniques cause non-uniform precipitation of AlN in the thickness direction of the slab. Therefore those methods are not always sufficient for manufacturing the magnetic steel strip of which uniformity of the property is important.
SUMMARY OF THE INVENTION
The present invention has been developed in view of the conventional problems as mentioned above. In order to realize . .
2 0 ~ ~ e3 ~ ~
the HDR technique in a process of manufacturing the magnetic steel strip, the invention makes it possible to control the precipitation of AlN and MnS in HDR, which has been hitherto a difficult problem, by means of a claimed original component designation and a claimed prescription of treatment conditions.
That is, the essence of the invention is to decrease the amounts of AlN and MnS precipitating during HDR to a level that they do not affect magnetic properties by regulating the Al and S contents and also to have i~evitably precipitating nitrides as coarse BN
precipitates.
A first invention comprises the steps of starting a hot roll-ing on a continuously cast slab which is composed of C: not more than 0.02 wt%, Si: 0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al: not more than 0.002 wt%, P: not more than 15 0.1 wt%,N: not more than 0.0030 wt%, the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000C, or at a state that the slab is reheated higher than 1000C from a temperature range where the slab has a surface temperature of not lower than 600C and is soaked for more than 10 min, coiling at temperature of higher than 650C following accomplish-ing the rolling at finishing temperature of higher than 820C, subjecting a cold rolling of once to the hot rolled steel strip or cold rollings of more than twice interposing a process anneal-ing, and continuosuly annealing at a range between temperatures ~. .
of 750 and 950C. --A second invéntion comprises carrying out a treatment under the same condition as above mentioned to a continuously cast slab , ,, ' ", , : , ,,, ,, ,. , . :'' . ' ' '.
20~ ,6 which is composed of C: not more than 0.02 wt~, Si: 0.1 to 1.5 wt~, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt~, Al: not more than 0.005 wt~, P: not more than 0.1 wt~, N: not more than 0.0030 wt~, B: 0.8 to 2.b in B(wt%)/N(wt%), the balance being Fe and unavoid-able impurities.
BRIEF DESCRIPTION OF THE DR~WING
Figure 1 shows a region of B/N where a low core loss value is obtained in a relationship with Al content.
DETEILED DESCRIPTION OF THE INVENTION
The present invention will be explained in detail together with limiting reasons thereof.
The limiting reasons of the steel composition will be referr-ed to.
C: The invention premises that a steel contains not more than 0.02 wt% at a steel making stage. In particular, in terms of a magnetic aging, it is desirable that C is less than 0.005 wt~ in the final products. For this purpose, a decarburization is carried out either by a vacuum-degassing treatment in the steelmaking or by a decarburization annealing during final annealing stage. -Si: This is an effective element for decreasing a core 7Oss value in the magnetic steel strip. In high-grade products where the low core loss value is essential, more than 2 wt~ Si is added.
However, with an increase in Si content, recrystallization of -ferrite does not sufficiently proceed during hot rolling and subsequent coiling. Thus, the annealing to the hot rolled band is required for obtaining desired properties. In the invention, however, the upper limit of Si is specified at 1.5 wt~ for the ,~ , - , ,, , . - : ,, ~ . . . . .
,,, : : , . . .
2 0 1~
purpose of supplying low-grade products without annealing hot rolled strips more economically. On the other hand, for the sake of decreasing the core loss value essential for manufacturing the magnetic steel strip, the lower limit of Si is 0.1 wt%.
Mn: When manufacturing the magnetic steel strip, Mn precipi-tates S as MnS during HDR. Therefore the amount of Mn is very important from the stand view of its size control. To precipitate S sufficiently in the steel, the invention specifies the lower limit of Mn at 0.1 wt~ and the upper limit at 1.0 wt% as the limit 10 not exerting bad influences to the magnetic properties.
S: Aiming at regulating a total amount of MnS precipitation during HDR, S content is specified at less than 0.005 wt%.
Al: This is an important element in the invention. Contrary to the conventional technologies which aim at controlling the size 15 and distribution of AlN precipitates, the invention decreases Al extremely, aiming at lowering AlN to the level where it does not arouse problems over the magnetic properties. Thus, Al is regula-ted to not more than 0.002 wt%. Nevertheless, in a case of B addi- ---tion as later mentioned, the excellent properties can be obtained 20 by specifying Al at not more than 0.005 wt% as shown in Figure 1. --P: This is a cheap and effective element to decrease the core ---loss of a low Si magnetic steel strip. However, much addition not only makes the strip hard but also causes the slab cracking.
Therefore its upper limit is 0.1 wt%.
N: This precipitates as fineAlN in the hot rolling process, and inhibits grain growth of ferrite not only in the hot rolled - -strip but in the cold rolled strip during final annealing. The invention is to check the precipitation of AlN as much as possible and to possibly precipitate it as BN by B addition as later stated - 2~ 0~6 and specifies the upper limit of N at 0.0030 wt~ to regulate the amounts of precipitations in both AlN and BN.
B: This is one of the most important element in the invention.
Particularly, by regulating the Al amount, B extremely decreases the amount of AlN which precipitates during HDR, and also makes N, which is unavoidably contained, precipitate as BN. Figure 1 illustrates that a region of B/N, in which the low core loss value is obtained (~W15/50 is a difference in the core loss value between HDR products and the conventional HCR products), in relation with the Al content. When Al is not more than 0.005 wt~, the low core loss value almost equivalent to ~hat of the ordinary HCR products is obtained in the scope of B/N being 0.8 to 2Ø Thus, in the invention, B is added within the scope of B/N of 0.8 to 2Ø
In the present invention, the continuously cast slab having the composition as mentioned above is directly rolled, and a slab temperature (slab surface temperature, hereinafter referred to the same) at which the direct rolling starts is specified at more than 1000C. Because if the starting temperature of the rolling is lower than 1000C, it is difficult to secure the finishing and coiling temperature specified by the invention, and insufficient to provide strain-induced precipitation in the hot rolling process as well as BN growth after the coiling. Moreover in the invention, if the slab temperature becomes lower than 1000C after casting, the lower limit is specified at 600C, and it is possible to per-form the rolling by reheating the slab to higher than 1000C froma temperature range of higher than 600C, so that the desired pro-perties may be obtained. When the slab temperature decreases lower than 600C, it is difficult to uniformly heat the slab into its interior by a short-time reheating treatment, and a slab soaking .. . .
20 ~ ~ 3~ ~
such as the conventional heat treatment becomes inevitable. In short, it spoils merits of the invention from an econo~ical view-point. In addition, with respect to a soaking time when reheating the slab, the required properties may be obtained if securing more than 10 minutes. Nevertheless if the soaking time is too long, it is not a good policy in term of the economy. That is, the soak-ing for not more than 40 min is preferable.
In the hot rolling, the finish rolling is performed at the temperature of higher than 820C and the coiling is done higher than 6S0C to secure the coiling temperature. In order to have the ferrite structure of hot ro'led strip recrystallize suffici-ently after coiling, in addition to the precipitation of BN, the invention stipulates a precondition that the strip is coiled at - -higher than 650C.
15The hot rolled steel strip is,according to the conventional process, continuously annealed at the temperature of 750 to 950C
after cold rolling of once or more than twice interposing the process annealing.
The above mentioned process annealing is usually performed 20 at the soaking temperature of around 750 to 900C. As to this -annealing practice,either a coil annealing or a continuous anneal- -ing will do.
The final annealing is carried out by the continuous anneal-ing. If the heating temperature is lower than 750C, the grain 25 growth is insufficient. Contrary, if it is exceeds 950C, ferrite grains grow excessively, resulting in a core loss increase.
,,~ . , f, , ' , ' i 2 ~
The continuously cast slabs having the chemical compositions of Nos.1, 3 and 18 shown in Table 1 were subjected to HDR (to thickness: 2.0 mm) under the condition shown in Table 2. Then the hot rolled strips were pickled and cold-rolled to a thickness of 0.5 mm. The final annealing was performed to the strip in the continuously annealing line. The obtained magnetic properties of the strips are shown in Table 2.
The continuously cast slabs having the compositions of Nos.
8 and 18 shown in Table 1 were reheated and hot-rolled to a thick-ness of 2.0 mm under the conditions shown in Table 3. The hot rolled strips were pickled and cold-rolled to a thickness of 0.5 mm, and the final annealing was applied to the strips in the continuous annealing line. The obtained magnetic properties of the strips are shown in Table 3.
The continuously cast slabs having the compositions shown in Table 1 were directly hot rolled without introducing into the 20 heating furnace at the surface temperature of higher than 1000C
and were hot-rolled to a thickness of 2.0 mm at the finishing -~
temperature between 820 and 870C, and were coiled at the tempera-ture of 680 to 710C and pickled, and cold-rolled to a thickness of O.S mm. The obtained magnetic properties of the strips by the 25 continuous annealing at the temperatures shown in Table 4-a and 4-b are shown. --" ',, , ,',, ' ', ' ,, '' ' ; ':'' i': ''' " ' '., ~ ' ' ,, ,, ' ', : ' , ,,: - . ., :
',, , ,, ,, ,, :, , . ::
. .
2 ~
Table 1 , '. ' ' ~ : _ H'~'H'~'H'~'~'H H'~'~ 'H'~.H.~,~.H'~ H
::::: . _ H o o-o,o o,o-o o o o o o~O~O-O~O O,O~o,o o~O~o~o~o 3 ~ ~ ~ -1 ~1 ~'~ ~ ~ ~ ~ ~'~ ~ ';; ;; --; _ -0 0.0 .0'0'0'0.0'0'0 0'0'0.0'0 0,0~0 C~
~- ~ ~ o. ~' ~ ~` ~. ~. ~1 7 ~ ~ ~ ~' o -- ~ ~ ~. ~ ~-, , . , : ' ', ', ', ', , '. , . ', ', '. '. . _ o.o.o'o'o.o o.o'o'o.o,o.o.o'.o,o'o o.o,o o o.o o o ~ ., ~, ~, ~' ~, ~ . ' ~. ~' o' o', ~, ~ o, ~, o o ~, ~, o ~ ~ o w ~, ~
: : : : , : : , : . : : : : : _ o.o.o o o o o o.o,o.o o.o,o.o o,o,o o.o o o o.o.o 3 o' o o' o, o', o', o', ~o. ~ ~o, ~o ~, o, o, o, o, 7 o q~ . '. . . . ' ' ' ', ' ', . ' , '. . . '. '. . '. _ o'.o'.o,o.o',o,o~,o.o,o,o,o',o~o,o~o~,o.o,o,o.o'o.o.o',o ,, . o o o o o. O~ O O O O o oo co~ o~ o o o o~ o o o o o o o C~
~-,~.~',~'.~'~'.~ ~'~.~ ~.~.~,~-~.~. * ~ ~.~ * ~,~.~ ~ _ U) o.o~o~o o o'o o~o'o o o,o,o,o,o'.o o',o,o, ,o~,o,o',o (D o~o'o~o o',o',o',o'o,o'O~o~o~o,o',o.o~o',o~o,~ 3~o~o,o',o o D o:o:o:o:o. O:l~: o: o: o: o: O: o: o: o: o: o: o: o: o:~ :---: o: o: o .
~vl.~.r ~ r r ~ ~-r '~'~'*'r r ' ~' ~r .~'~. ~ ~r ~ ~ ~
0~0,0,0~0',0~O,O',O',O~O~O~O,O,O~,O,O'~O~,O'~O,O~'O,O,O',O .
0,0,0~0~0~0~o~oo~o~o~oo~oo~o.oo~oo~oo~o~o~o~o~o~o~o~- 'O Z
0 ~-:r~:r~ -:r~:r~:r~:~a:~-:r~:r~ .r~.r~.~ .r~.~ -vl ~-- o _7, a~, _1, co, r~. O, c~- ~ ~D 1--, o, c~, cn. oo, ~- o, vl- --- o oo to. _l _ : -O O, ~ ~0'0,0~O,O, , '~0'.0', ',0',0',0~0'O~ ~0,0,0'o, ', ~' ~" '.
~h O~ '~ '~ ' ' ' I ' I ' o' o' I, O', 0, O~ O~ O~ I ~ O~ O~ O~ O' I ~ I W
O Vl' ~ ' O~ 0'00~' O~ ' ,Vl', ~ ~r~ o',~-vl~ Vl' O' ~
D) . . . _ ., ~ : : : : : : ' , ~ ~ , : : : : : : : :
3 ~ 0;o ~ ~ ~ ~ ~ O O ~ ~ ~ ~ ~; ~ r '~r ~ r ~ O D
g _~
_ 9 _ : ' ,~ ,., ;,`
~, , "' ,, ~ , ', - :ti ,. , , , ~, , , , , " , , , ~, ...
", , ., , , i , , . . . .. . . .
201 ~86 Table 2 - A ~ D E F Bso :
~n (nC) (nc) (C) (~C) (T) ~Is/sn C 1120 830 700 720* 1.77 8.15 . ii20 830 700 760 i;82 i;~5 1 . li20 850 730 760 i;i3 i;25 I ¦1100 8~0 730 800 1.80 7.20 C 1100 830 630* 800 .1.75 7.95 _ C 960* 770* 730 800 1i;73 7.76 I ¦1100 850 720 770 1.79 7.35 C 1100 790* 720 770 1.`74 7.56 3 I 1100 850 700 800 1.78 7.26 C 1100 850 620* 800 1.75 8.15 ......... ............. ............. ............. ........ ~.. ............ .............
_ _C _50* 790* 720 _0 1.7~ 7.65 I 1100 8Z0 720 820 1.70 ~ .73 I 1120 820 7~0 820 1.71 ~.69 ......... ............ ............ ............. ............. ............ ......... , I 1120 850 760 850 1.73 4.65 ......... ............. ............ ............. ............. ............ .............
18 C990* 820 750 850 1.71 5.03 C1100 780* 710 850 1.70 5.27 C1120 850 620* 850 1.68 5.85 I1150 870 780 850 1.7~ 4.55 I1120 860 680 760 1.82 7.63 ......... ............. ............ ............. ............. ............ ............. ..
23 C 1120 860 600* 760 1.76 8.15 ... . -1l00 S00~ 700 760 1.78 - 5-.09 -- -..
A: Process; B: HDR starting temperature C: Comparative condition; D: Finishing temperature E: Coiling temperature: F: Final annealing temperature -- -I: Inventive condition; * out of claimed condition : --G: Magnetic properties ~ -" , .~, ,, .,, ", . , , , ,, , ", :" , .
2 ~
Table 3 ,_ * ~, ~ ~ b . . . . . . . . . . . .
.. .. .. .. .. : : : : : :
O ~ U) (-) ~ (1 (1, 0, )--(, (`) H ' H () ' (~ ) ' H ' O ' H . H b C tD 1-- 0 )t : : : : : : : : : : , :
~ 5 ~ o : : : : : : : : : : : :
O ~) 'J ,'- (D . . -, . . ., , . _ ~ a) _~. ~'. _l' ~. -~. _~ _~
`- o: o: o: cn: o: o: cs~ o: o: o: o: o: o: o (~Z
O, O, O, O' O' O, O O, O' O, O~ 0~, O, O
D~ D) (~ : : *: : : : : : *: : *: :
3 o . ~ . : ::
3 tD ~ - . . . ~ . . . .
3 ~ ~ ,~ ,~ ,_ I~ ~ ~ ~ ~I :C
O 0 CJ~ l CJI 0 cn ~: ~: c ~: o: o: ~: O ~ ~
o ~ o C ~ O~ O~ O~ O~ O- O, O O~ 0 O', O O O~ O _, C ~ . . ............ . ~ ~, .
. , .
..1-- o~ cn o). ~ a) a) ~ -- w ~ ~ a) ~ El ~
g O ~ Ccn~o~o~o~o~o',o O' 1~0'0~0'0,0 1-::::'' .,, ,. _ ,' "~. 8 -- :-,~ ., ~, ~, ~, ~ . ~ . ~ ~ ..
~- O -Dl Q~ o: o: o: o: o o o ~D, O 0, O' '` t1 ~,. ~ a) o) ~ ~ ~ ~ 1 Hr~ O ' O ' O ' O . 0: 0: 0 0: 0: 0 ' O ' O, O ' O ~_ : -~- ~ g 0- . ~,, '. *, ',,,, '. . ,, ., ...... , ~ ', :~ ~D `- : : : : : : : : : : : : , ., ~rt~ :::::: ::::~ ,_ '.
1-- 3 ~ l C~:~:~:~:~:~:~ ~--:_l:cn:al:~):a):a~ 1 3:
1'-~a(D~.. o.ooo.o~oo o~o~o~o~o~o~o ~_ 5 n ~ : ~ : :
~ ~ '- ' ' ' : : : : ' . , , . .
o8 c ~ 3 ~,. ~ 1 o~ ~ t~3 . : . .
o: oo: 1-- o: o: ~: o _J 0: 00: 00: 00 0 00 ID 5 o: o: o: o: o: o: o o: o: o: o: o: o: o ~_ '- : : : : ~ ~ . . . . . . .
o t~ ~ c ~4 ~ ~ . . _ _ . ~ ~ ', '. . ~ ~, , . _~ ,-c.n: ~J~: Vl: cn: o: o: o 0: o: o: o o~ v~ ~2 ~:1 O ~o, o o', o, o~ o, o o, o, o, o, o' o' o '-- ., .
Z 1~D : : : : : : _. : : : : ~. , ...... .. ~'. _ ~t ~l^, X ~t )~ ~ _~ .- .-C :. :. :- :. :. :. . :- :. :. :- :. :-3 5 .. 1 ~ ~ v--~: v~: ~ : v~: ~ ~ : ~ ~J o ~v ~ (D ~ v', ~J~ v~ O, C~ ~' 00, ~1 ~_ ~ ., A" ~ ~
,. . ' ............ . ' '. '~ ' . ...
~ ~q ~ n : : : : . . . . . ,_ C rt v: cn: ~: ~: v~: ~: ~ o): v): v: CJl: V~ cn: cn 6 A ,_ . :. :. : :. : : : :. : :. :. : ~ I' 3 lol Vl' o, ~ ~ V-l, cOrl v~, v~ , ~' o~ o ~ ~ ~.
~V ~V : : : : : : : : : : : : ~
. . . . ~ _ ~ ~ .
rt 1. ...
~D
~D
2010~3~
Table 4-a . I .
~o. I B soW-~s/so ( C) ( T )(w/kg) 1 760 1.817 35 800 i ;807 20 2 760 1.757.45 ........................ ......................... ......................... 800 1.757_.23 3 7 ~~0 1.80-7.29 ~
800 i ;797 ; 25 __ 760 1.757.90 800 ï ;747 ; 86 760 1.72~ .--12 800 - - ï ;72_ 8.0 i 6 --- 760 1.77 7.20 ....................... ......................... .........................800 1.75 '7.02 7 760 1.72 7 55 .-800 ï; 72 7 25 8 800 1.77 5 82 850 ï; 76 5 '73 9 ~ 800 1.75 6.65 850 ï ;7 ~ 6 ;54 ..
ï o -I 800 I 1.76--l 6-.46 850 i ;75 6 ; 32 _ ..
ll 8---00 1.73 6.60-85 -0 ï ; 73 - 6.5-4-12 1 800 1 1.69 - -6.89 - 850 ï ; 70 - 6.85 13 1 800 1.. 7-;6 6.45 1 -1 850 1.7-5 6.24 1 --.-:
1~ 800 1.77 16.00 850 - ï ; 76 5 ;94 F: Final annealing temperature G: Magnetic properties ,,,,, ,, , ." "-,,,, ,.,..,, . ., . ., , ,- , ., , ., . , ~. . : .
, ., . . , , , , , , . , ,, ,, ,, . , . :
20:~as~
. Table 4-b NQ . . ~
( C ) ( '~' ) (w/ kg ) 850 1.72 5.89 16 840 1.71 4.78 _ 880 1.70 4.65 17 ~3 ~ 0 1.75 4.60 .. 8 ~30 i; 73 4; 50 18 840 11 -74 4.72 880 1.73 4.64 l9 840 1.70 5.23 880 1.70 5.01 ~340 .1..... 6... 9.. ..... 5... 4.5 ~380 1.~ 9 5.32 211 8 ~ 0 1.75 4.62 880 1.75 4.57 22 ~380 - .. 1.. ~ .. 3.. ...... 4.. ~ .. .5 '320 1. G 3 3.95 23 7 ~ 0 1.82 7.63 780 1.81 7.59 2~ 760 ..... 1.. 7... ?.. 8.30 1 780 1 1.75 8.00 25 760 1.81 7.70 780 ï; 83 7; 50 F: Final annealing temperature G: Magnetic properties -. ~ , , , , , : , . ~,, .
is coarsened by self-annealing effect (Patent Publication No.57-43132).
Most of these technologies are based on the premise of the conventional processes which consist of slab reheating and hot rolling. However, taking it into consideration to employ the direct rolling regarded as promising in terms of energy- and process-savings, the above technologies alone are insufficient to obtain the excellent magnetic properties, because in the direct rolling, AlN or MnS finely precipitate in steel during the hot rolling process.
Therefore from the viewpoint of solving the above problems, as a method of coarsening AlN in HDR, technologies have been pro-posed to coarsen AlN by briefly heating the slab on the way of 20 HDR as taught in Patent Publications No.56-18045, No.56-33451 and Laid-Open No.58-123825. However, these techniques cause non-uniform precipitation of AlN in the thickness direction of the slab. Therefore those methods are not always sufficient for manufacturing the magnetic steel strip of which uniformity of the property is important.
SUMMARY OF THE INVENTION
The present invention has been developed in view of the conventional problems as mentioned above. In order to realize . .
2 0 ~ ~ e3 ~ ~
the HDR technique in a process of manufacturing the magnetic steel strip, the invention makes it possible to control the precipitation of AlN and MnS in HDR, which has been hitherto a difficult problem, by means of a claimed original component designation and a claimed prescription of treatment conditions.
That is, the essence of the invention is to decrease the amounts of AlN and MnS precipitating during HDR to a level that they do not affect magnetic properties by regulating the Al and S contents and also to have i~evitably precipitating nitrides as coarse BN
precipitates.
A first invention comprises the steps of starting a hot roll-ing on a continuously cast slab which is composed of C: not more than 0.02 wt%, Si: 0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al: not more than 0.002 wt%, P: not more than 15 0.1 wt%,N: not more than 0.0030 wt%, the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000C, or at a state that the slab is reheated higher than 1000C from a temperature range where the slab has a surface temperature of not lower than 600C and is soaked for more than 10 min, coiling at temperature of higher than 650C following accomplish-ing the rolling at finishing temperature of higher than 820C, subjecting a cold rolling of once to the hot rolled steel strip or cold rollings of more than twice interposing a process anneal-ing, and continuosuly annealing at a range between temperatures ~. .
of 750 and 950C. --A second invéntion comprises carrying out a treatment under the same condition as above mentioned to a continuously cast slab , ,, ' ", , : , ,,, ,, ,. , . :'' . ' ' '.
20~ ,6 which is composed of C: not more than 0.02 wt~, Si: 0.1 to 1.5 wt~, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt~, Al: not more than 0.005 wt~, P: not more than 0.1 wt~, N: not more than 0.0030 wt~, B: 0.8 to 2.b in B(wt%)/N(wt%), the balance being Fe and unavoid-able impurities.
BRIEF DESCRIPTION OF THE DR~WING
Figure 1 shows a region of B/N where a low core loss value is obtained in a relationship with Al content.
DETEILED DESCRIPTION OF THE INVENTION
The present invention will be explained in detail together with limiting reasons thereof.
The limiting reasons of the steel composition will be referr-ed to.
C: The invention premises that a steel contains not more than 0.02 wt% at a steel making stage. In particular, in terms of a magnetic aging, it is desirable that C is less than 0.005 wt~ in the final products. For this purpose, a decarburization is carried out either by a vacuum-degassing treatment in the steelmaking or by a decarburization annealing during final annealing stage. -Si: This is an effective element for decreasing a core 7Oss value in the magnetic steel strip. In high-grade products where the low core loss value is essential, more than 2 wt~ Si is added.
However, with an increase in Si content, recrystallization of -ferrite does not sufficiently proceed during hot rolling and subsequent coiling. Thus, the annealing to the hot rolled band is required for obtaining desired properties. In the invention, however, the upper limit of Si is specified at 1.5 wt~ for the ,~ , - , ,, , . - : ,, ~ . . . . .
,,, : : , . . .
2 0 1~
purpose of supplying low-grade products without annealing hot rolled strips more economically. On the other hand, for the sake of decreasing the core loss value essential for manufacturing the magnetic steel strip, the lower limit of Si is 0.1 wt%.
Mn: When manufacturing the magnetic steel strip, Mn precipi-tates S as MnS during HDR. Therefore the amount of Mn is very important from the stand view of its size control. To precipitate S sufficiently in the steel, the invention specifies the lower limit of Mn at 0.1 wt~ and the upper limit at 1.0 wt% as the limit 10 not exerting bad influences to the magnetic properties.
S: Aiming at regulating a total amount of MnS precipitation during HDR, S content is specified at less than 0.005 wt%.
Al: This is an important element in the invention. Contrary to the conventional technologies which aim at controlling the size 15 and distribution of AlN precipitates, the invention decreases Al extremely, aiming at lowering AlN to the level where it does not arouse problems over the magnetic properties. Thus, Al is regula-ted to not more than 0.002 wt%. Nevertheless, in a case of B addi- ---tion as later mentioned, the excellent properties can be obtained 20 by specifying Al at not more than 0.005 wt% as shown in Figure 1. --P: This is a cheap and effective element to decrease the core ---loss of a low Si magnetic steel strip. However, much addition not only makes the strip hard but also causes the slab cracking.
Therefore its upper limit is 0.1 wt%.
N: This precipitates as fineAlN in the hot rolling process, and inhibits grain growth of ferrite not only in the hot rolled - -strip but in the cold rolled strip during final annealing. The invention is to check the precipitation of AlN as much as possible and to possibly precipitate it as BN by B addition as later stated - 2~ 0~6 and specifies the upper limit of N at 0.0030 wt~ to regulate the amounts of precipitations in both AlN and BN.
B: This is one of the most important element in the invention.
Particularly, by regulating the Al amount, B extremely decreases the amount of AlN which precipitates during HDR, and also makes N, which is unavoidably contained, precipitate as BN. Figure 1 illustrates that a region of B/N, in which the low core loss value is obtained (~W15/50 is a difference in the core loss value between HDR products and the conventional HCR products), in relation with the Al content. When Al is not more than 0.005 wt~, the low core loss value almost equivalent to ~hat of the ordinary HCR products is obtained in the scope of B/N being 0.8 to 2Ø Thus, in the invention, B is added within the scope of B/N of 0.8 to 2Ø
In the present invention, the continuously cast slab having the composition as mentioned above is directly rolled, and a slab temperature (slab surface temperature, hereinafter referred to the same) at which the direct rolling starts is specified at more than 1000C. Because if the starting temperature of the rolling is lower than 1000C, it is difficult to secure the finishing and coiling temperature specified by the invention, and insufficient to provide strain-induced precipitation in the hot rolling process as well as BN growth after the coiling. Moreover in the invention, if the slab temperature becomes lower than 1000C after casting, the lower limit is specified at 600C, and it is possible to per-form the rolling by reheating the slab to higher than 1000C froma temperature range of higher than 600C, so that the desired pro-perties may be obtained. When the slab temperature decreases lower than 600C, it is difficult to uniformly heat the slab into its interior by a short-time reheating treatment, and a slab soaking .. . .
20 ~ ~ 3~ ~
such as the conventional heat treatment becomes inevitable. In short, it spoils merits of the invention from an econo~ical view-point. In addition, with respect to a soaking time when reheating the slab, the required properties may be obtained if securing more than 10 minutes. Nevertheless if the soaking time is too long, it is not a good policy in term of the economy. That is, the soak-ing for not more than 40 min is preferable.
In the hot rolling, the finish rolling is performed at the temperature of higher than 820C and the coiling is done higher than 6S0C to secure the coiling temperature. In order to have the ferrite structure of hot ro'led strip recrystallize suffici-ently after coiling, in addition to the precipitation of BN, the invention stipulates a precondition that the strip is coiled at - -higher than 650C.
15The hot rolled steel strip is,according to the conventional process, continuously annealed at the temperature of 750 to 950C
after cold rolling of once or more than twice interposing the process annealing.
The above mentioned process annealing is usually performed 20 at the soaking temperature of around 750 to 900C. As to this -annealing practice,either a coil annealing or a continuous anneal- -ing will do.
The final annealing is carried out by the continuous anneal-ing. If the heating temperature is lower than 750C, the grain 25 growth is insufficient. Contrary, if it is exceeds 950C, ferrite grains grow excessively, resulting in a core loss increase.
,,~ . , f, , ' , ' i 2 ~
The continuously cast slabs having the chemical compositions of Nos.1, 3 and 18 shown in Table 1 were subjected to HDR (to thickness: 2.0 mm) under the condition shown in Table 2. Then the hot rolled strips were pickled and cold-rolled to a thickness of 0.5 mm. The final annealing was performed to the strip in the continuously annealing line. The obtained magnetic properties of the strips are shown in Table 2.
The continuously cast slabs having the compositions of Nos.
8 and 18 shown in Table 1 were reheated and hot-rolled to a thick-ness of 2.0 mm under the conditions shown in Table 3. The hot rolled strips were pickled and cold-rolled to a thickness of 0.5 mm, and the final annealing was applied to the strips in the continuous annealing line. The obtained magnetic properties of the strips are shown in Table 3.
The continuously cast slabs having the compositions shown in Table 1 were directly hot rolled without introducing into the 20 heating furnace at the surface temperature of higher than 1000C
and were hot-rolled to a thickness of 2.0 mm at the finishing -~
temperature between 820 and 870C, and were coiled at the tempera-ture of 680 to 710C and pickled, and cold-rolled to a thickness of O.S mm. The obtained magnetic properties of the strips by the 25 continuous annealing at the temperatures shown in Table 4-a and 4-b are shown. --" ',, , ,',, ' ', ' ,, '' ' ; ':'' i': ''' " ' '., ~ ' ' ,, ,, ' ', : ' , ,,: - . ., :
',, , ,, ,, ,, :, , . ::
. .
2 ~
Table 1 , '. ' ' ~ : _ H'~'H'~'H'~'~'H H'~'~ 'H'~.H.~,~.H'~ H
::::: . _ H o o-o,o o,o-o o o o o o~O~O-O~O O,O~o,o o~O~o~o~o 3 ~ ~ ~ -1 ~1 ~'~ ~ ~ ~ ~ ~'~ ~ ';; ;; --; _ -0 0.0 .0'0'0'0.0'0'0 0'0'0.0'0 0,0~0 C~
~- ~ ~ o. ~' ~ ~` ~. ~. ~1 7 ~ ~ ~ ~' o -- ~ ~ ~. ~ ~-, , . , : ' ', ', ', ', , '. , . ', ', '. '. . _ o.o.o'o'o.o o.o'o'o.o,o.o.o'.o,o'o o.o,o o o.o o o ~ ., ~, ~, ~' ~, ~ . ' ~. ~' o' o', ~, ~ o, ~, o o ~, ~, o ~ ~ o w ~, ~
: : : : , : : , : . : : : : : _ o.o.o o o o o o.o,o.o o.o,o.o o,o,o o.o o o o.o.o 3 o' o o' o, o', o', o', ~o. ~ ~o, ~o ~, o, o, o, o, 7 o q~ . '. . . . ' ' ' ', ' ', . ' , '. . . '. '. . '. _ o'.o'.o,o.o',o,o~,o.o,o,o,o',o~o,o~o~,o.o,o,o.o'o.o.o',o ,, . o o o o o. O~ O O O O o oo co~ o~ o o o o~ o o o o o o o C~
~-,~.~',~'.~'~'.~ ~'~.~ ~.~.~,~-~.~. * ~ ~.~ * ~,~.~ ~ _ U) o.o~o~o o o'o o~o'o o o,o,o,o,o'.o o',o,o, ,o~,o,o',o (D o~o'o~o o',o',o',o'o,o'O~o~o~o,o',o.o~o',o~o,~ 3~o~o,o',o o D o:o:o:o:o. O:l~: o: o: o: o: O: o: o: o: o: o: o: o: o:~ :---: o: o: o .
~vl.~.r ~ r r ~ ~-r '~'~'*'r r ' ~' ~r .~'~. ~ ~r ~ ~ ~
0~0,0,0~0',0~O,O',O',O~O~O~O,O,O~,O,O'~O~,O'~O,O~'O,O,O',O .
0,0,0~0~0~0~o~oo~o~o~oo~oo~o.oo~oo~oo~o~o~o~o~o~o~o~- 'O Z
0 ~-:r~:r~ -:r~:r~:r~:~a:~-:r~:r~ .r~.r~.~ .r~.~ -vl ~-- o _7, a~, _1, co, r~. O, c~- ~ ~D 1--, o, c~, cn. oo, ~- o, vl- --- o oo to. _l _ : -O O, ~ ~0'0,0~O,O, , '~0'.0', ',0',0',0~0'O~ ~0,0,0'o, ', ~' ~" '.
~h O~ '~ '~ ' ' ' I ' I ' o' o' I, O', 0, O~ O~ O~ I ~ O~ O~ O~ O' I ~ I W
O Vl' ~ ' O~ 0'00~' O~ ' ,Vl', ~ ~r~ o',~-vl~ Vl' O' ~
D) . . . _ ., ~ : : : : : : ' , ~ ~ , : : : : : : : :
3 ~ 0;o ~ ~ ~ ~ ~ O O ~ ~ ~ ~ ~; ~ r '~r ~ r ~ O D
g _~
_ 9 _ : ' ,~ ,., ;,`
~, , "' ,, ~ , ', - :ti ,. , , , ~, , , , , " , , , ~, ...
", , ., , , i , , . . . .. . . .
201 ~86 Table 2 - A ~ D E F Bso :
~n (nC) (nc) (C) (~C) (T) ~Is/sn C 1120 830 700 720* 1.77 8.15 . ii20 830 700 760 i;82 i;~5 1 . li20 850 730 760 i;i3 i;25 I ¦1100 8~0 730 800 1.80 7.20 C 1100 830 630* 800 .1.75 7.95 _ C 960* 770* 730 800 1i;73 7.76 I ¦1100 850 720 770 1.79 7.35 C 1100 790* 720 770 1.`74 7.56 3 I 1100 850 700 800 1.78 7.26 C 1100 850 620* 800 1.75 8.15 ......... ............. ............. ............. ........ ~.. ............ .............
_ _C _50* 790* 720 _0 1.7~ 7.65 I 1100 8Z0 720 820 1.70 ~ .73 I 1120 820 7~0 820 1.71 ~.69 ......... ............ ............ ............. ............. ............ ......... , I 1120 850 760 850 1.73 4.65 ......... ............. ............ ............. ............. ............ .............
18 C990* 820 750 850 1.71 5.03 C1100 780* 710 850 1.70 5.27 C1120 850 620* 850 1.68 5.85 I1150 870 780 850 1.7~ 4.55 I1120 860 680 760 1.82 7.63 ......... ............. ............ ............. ............. ............ ............. ..
23 C 1120 860 600* 760 1.76 8.15 ... . -1l00 S00~ 700 760 1.78 - 5-.09 -- -..
A: Process; B: HDR starting temperature C: Comparative condition; D: Finishing temperature E: Coiling temperature: F: Final annealing temperature -- -I: Inventive condition; * out of claimed condition : --G: Magnetic properties ~ -" , .~, ,, .,, ", . , , , ,, , ", :" , .
2 ~
Table 3 ,_ * ~, ~ ~ b . . . . . . . . . . . .
.. .. .. .. .. : : : : : :
O ~ U) (-) ~ (1 (1, 0, )--(, (`) H ' H () ' (~ ) ' H ' O ' H . H b C tD 1-- 0 )t : : : : : : : : : : , :
~ 5 ~ o : : : : : : : : : : : :
O ~) 'J ,'- (D . . -, . . ., , . _ ~ a) _~. ~'. _l' ~. -~. _~ _~
`- o: o: o: cn: o: o: cs~ o: o: o: o: o: o: o (~Z
O, O, O, O' O' O, O O, O' O, O~ 0~, O, O
D~ D) (~ : : *: : : : : : *: : *: :
3 o . ~ . : ::
3 tD ~ - . . . ~ . . . .
3 ~ ~ ,~ ,~ ,_ I~ ~ ~ ~ ~I :C
O 0 CJ~ l CJI 0 cn ~: ~: c ~: o: o: ~: O ~ ~
o ~ o C ~ O~ O~ O~ O~ O- O, O O~ 0 O', O O O~ O _, C ~ . . ............ . ~ ~, .
. , .
..1-- o~ cn o). ~ a) a) ~ -- w ~ ~ a) ~ El ~
g O ~ Ccn~o~o~o~o~o',o O' 1~0'0~0'0,0 1-::::'' .,, ,. _ ,' "~. 8 -- :-,~ ., ~, ~, ~, ~ . ~ . ~ ~ ..
~- O -Dl Q~ o: o: o: o: o o o ~D, O 0, O' '` t1 ~,. ~ a) o) ~ ~ ~ ~ 1 Hr~ O ' O ' O ' O . 0: 0: 0 0: 0: 0 ' O ' O, O ' O ~_ : -~- ~ g 0- . ~,, '. *, ',,,, '. . ,, ., ...... , ~ ', :~ ~D `- : : : : : : : : : : : : , ., ~rt~ :::::: ::::~ ,_ '.
1-- 3 ~ l C~:~:~:~:~:~:~ ~--:_l:cn:al:~):a):a~ 1 3:
1'-~a(D~.. o.ooo.o~oo o~o~o~o~o~o~o ~_ 5 n ~ : ~ : :
~ ~ '- ' ' ' : : : : ' . , , . .
o8 c ~ 3 ~,. ~ 1 o~ ~ t~3 . : . .
o: oo: 1-- o: o: ~: o _J 0: 00: 00: 00 0 00 ID 5 o: o: o: o: o: o: o o: o: o: o: o: o: o ~_ '- : : : : ~ ~ . . . . . . .
o t~ ~ c ~4 ~ ~ . . _ _ . ~ ~ ', '. . ~ ~, , . _~ ,-c.n: ~J~: Vl: cn: o: o: o 0: o: o: o o~ v~ ~2 ~:1 O ~o, o o', o, o~ o, o o, o, o, o, o' o' o '-- ., .
Z 1~D : : : : : : _. : : : : ~. , ...... .. ~'. _ ~t ~l^, X ~t )~ ~ _~ .- .-C :. :. :- :. :. :. . :- :. :. :- :. :-3 5 .. 1 ~ ~ v--~: v~: ~ : v~: ~ ~ : ~ ~J o ~v ~ (D ~ v', ~J~ v~ O, C~ ~' 00, ~1 ~_ ~ ., A" ~ ~
,. . ' ............ . ' '. '~ ' . ...
~ ~q ~ n : : : : . . . . . ,_ C rt v: cn: ~: ~: v~: ~: ~ o): v): v: CJl: V~ cn: cn 6 A ,_ . :. :. : :. : : : :. : :. :. : ~ I' 3 lol Vl' o, ~ ~ V-l, cOrl v~, v~ , ~' o~ o ~ ~ ~.
~V ~V : : : : : : : : : : : : ~
. . . . ~ _ ~ ~ .
rt 1. ...
~D
~D
2010~3~
Table 4-a . I .
~o. I B soW-~s/so ( C) ( T )(w/kg) 1 760 1.817 35 800 i ;807 20 2 760 1.757.45 ........................ ......................... ......................... 800 1.757_.23 3 7 ~~0 1.80-7.29 ~
800 i ;797 ; 25 __ 760 1.757.90 800 ï ;747 ; 86 760 1.72~ .--12 800 - - ï ;72_ 8.0 i 6 --- 760 1.77 7.20 ....................... ......................... .........................800 1.75 '7.02 7 760 1.72 7 55 .-800 ï; 72 7 25 8 800 1.77 5 82 850 ï; 76 5 '73 9 ~ 800 1.75 6.65 850 ï ;7 ~ 6 ;54 ..
ï o -I 800 I 1.76--l 6-.46 850 i ;75 6 ; 32 _ ..
ll 8---00 1.73 6.60-85 -0 ï ; 73 - 6.5-4-12 1 800 1 1.69 - -6.89 - 850 ï ; 70 - 6.85 13 1 800 1.. 7-;6 6.45 1 -1 850 1.7-5 6.24 1 --.-:
1~ 800 1.77 16.00 850 - ï ; 76 5 ;94 F: Final annealing temperature G: Magnetic properties ,,,,, ,, , ." "-,,,, ,.,..,, . ., . ., , ,- , ., , ., . , ~. . : .
, ., . . , , , , , , . , ,, ,, ,, . , . :
20:~as~
. Table 4-b NQ . . ~
( C ) ( '~' ) (w/ kg ) 850 1.72 5.89 16 840 1.71 4.78 _ 880 1.70 4.65 17 ~3 ~ 0 1.75 4.60 .. 8 ~30 i; 73 4; 50 18 840 11 -74 4.72 880 1.73 4.64 l9 840 1.70 5.23 880 1.70 5.01 ~340 .1..... 6... 9.. ..... 5... 4.5 ~380 1.~ 9 5.32 211 8 ~ 0 1.75 4.62 880 1.75 4.57 22 ~380 - .. 1.. ~ .. 3.. ...... 4.. ~ .. .5 '320 1. G 3 3.95 23 7 ~ 0 1.82 7.63 780 1.81 7.59 2~ 760 ..... 1.. 7... ?.. 8.30 1 780 1 1.75 8.00 25 760 1.81 7.70 780 ï; 83 7; 50 F: Final annealing temperature G: Magnetic properties -. ~ , , , , , : , . ~,, .
Claims (6)
1. A method of manufacturing non-oriented magnetic steel strips, comprising the steps of starting a hot rolling on a continuously cast slab which is composed of C: not more than 0.02 wt%, Si:
0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al:
not more than 0.002 wt%, P: not more than 0.1 wt%, N: not more than 0.0030 wt%, the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000°C, or at a state that the slab is reheated to higher than 1000°C from a temperatrue range where the slab has a surface temperature of not lower than 600°C and is soaked for more than 10 min, coiling at a temperature which is higher than 650°C following accomplishing the hot-rolling at finishing temperature which is higher than 820°C, subjecting a cold-rolling of once to the hot rolled steel strip or cold rollings of more than twice interposing a process annealing thereto, and continuously annealing at a range between temperatures of 750 and 950°C.
0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al:
not more than 0.002 wt%, P: not more than 0.1 wt%, N: not more than 0.0030 wt%, the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000°C, or at a state that the slab is reheated to higher than 1000°C from a temperatrue range where the slab has a surface temperature of not lower than 600°C and is soaked for more than 10 min, coiling at a temperature which is higher than 650°C following accomplishing the hot-rolling at finishing temperature which is higher than 820°C, subjecting a cold-rolling of once to the hot rolled steel strip or cold rollings of more than twice interposing a process annealing thereto, and continuously annealing at a range between temperatures of 750 and 950°C.
2. A method of manufacturing non-oriented magnetic steel strips, comprising the steps of starting a hot rolling on a continuously cast slab which is composed of C: less than 0.005 wt%, Si: 0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al: not more than 0.002 wt%, P: not more than 0.1 wt%, N: not more than 0.0030 wt%, the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000°C, or at a state that the slab is reheated to higher than 1000°C from a temperature range where the slab has a surface temperature of not lower than 600°C and is soaked for more than 10 min, coiling at a temperature which is higher than 650°C following accomplishing the hot-rolling at finishing temperature which is higher than 820°C, subjecting a cold-rolling of once to the hot-rolled steel strip or cold rollings of more than twice interposing a process annealing thereto, and continuously annealing at a range between temperatures of 750 and 950°C.
3. A method of manufacturing non-oriented magnetic steel strips, comprising the steps of starting a hot rolling in a continuously cast slab which is composed of C: not more than 0.02 wt%, Si:
0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al:
not more than 0.002 wt%, P: not more than 0.1 wt%, N:not more than 0.0030 wt%, the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000°C,or at a state that the slab is reheated to higher than 1000°C from a temperature range where the slab has a surface temperature of not lower than 600°C and is soaked for more than 10 min, coiling at a temperature which is higher than 650°C following accomplishing the hot-rolling at finishing temperature of more than 820°C,subjecting a cold-rolling of once to the hot-rolled steel strip or cold rollings of more than twice interposing a process annealing thereto, and continuously annealing serving as a de-carburization annealing at a range between temperatures of 750°C
and 950°C, thereby to decrease the C content less than 0.005 wt.
0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al:
not more than 0.002 wt%, P: not more than 0.1 wt%, N:not more than 0.0030 wt%, the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000°C,or at a state that the slab is reheated to higher than 1000°C from a temperature range where the slab has a surface temperature of not lower than 600°C and is soaked for more than 10 min, coiling at a temperature which is higher than 650°C following accomplishing the hot-rolling at finishing temperature of more than 820°C,subjecting a cold-rolling of once to the hot-rolled steel strip or cold rollings of more than twice interposing a process annealing thereto, and continuously annealing serving as a de-carburization annealing at a range between temperatures of 750°C
and 950°C, thereby to decrease the C content less than 0.005 wt.
4. A method of manufacturing non-oriented magnetic steel strips, comprising the steps of starting a hot rolling on a continuously cast slab which is composed of C: not more than 0.02 wt%, Si:
0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al:
not more than 0.005 wt%, P: not more than 0.1 wt%, N: not more than 0.0030 wt%, B: 0.8 to 2.0 in B(wt%)/N(wt%ff), the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000°C, or at a state that the slab is reheated to higher than 1000°C from a temperature range where the slab has a surface temperature of not lower than 600°C and is soaked for more than 10 min, coiling at temperature which is higher than 650°C following accomplishing the rolling at finishing temperature of more than 820°C, subjecting a cold-rolling of once to the hot rolled steel strip or cold-rollings of more than twice interposing a process annealing thereto, and continuously annealing at a range between temperatures of 750 and 950°C.
0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al:
not more than 0.005 wt%, P: not more than 0.1 wt%, N: not more than 0.0030 wt%, B: 0.8 to 2.0 in B(wt%)/N(wt%ff), the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000°C, or at a state that the slab is reheated to higher than 1000°C from a temperature range where the slab has a surface temperature of not lower than 600°C and is soaked for more than 10 min, coiling at temperature which is higher than 650°C following accomplishing the rolling at finishing temperature of more than 820°C, subjecting a cold-rolling of once to the hot rolled steel strip or cold-rollings of more than twice interposing a process annealing thereto, and continuously annealing at a range between temperatures of 750 and 950°C.
5. A method of manufacturing non-oriented magnetic steel strips, comprising the steps of starting a hot rolling on a continuously cast slab which is composed of C: less than 0.005 wt%, Si: 0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al: not more than 0.005 wt%, P: not more than 0.1 wt%, N: not more than 0.0030 wt%, B: 0.8 to 2.0 in B(wt%)/N (wt%), the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000°C, or at a state that the slab is reheated to higher than 1000°C from a temperature range where the slab has a surface temperature not lower than 600°C
and is soaked for more than 10 min, coiling at temperature of more than 650°C following accomplishing the rolling at finishing temperature of more than 820°C, subjecting a cold rolling of once to the hot rolled steel strip or cold rollings of more than twice interposing a process annealing thereto, and continuously annealing at a range between temperatures of 750 and 950°C.
and is soaked for more than 10 min, coiling at temperature of more than 650°C following accomplishing the rolling at finishing temperature of more than 820°C, subjecting a cold rolling of once to the hot rolled steel strip or cold rollings of more than twice interposing a process annealing thereto, and continuously annealing at a range between temperatures of 750 and 950°C.
6. A method of manufacturing non-oriented magnetic steel strips, comprising the steps of starting a hot rolling on a continuously cast slab which is composed of C: not more than 0.02 wt%, Si:
0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al:
not more than 0.005 wt%, P: not more than 0.1 wt%,N: not more than 0.0030 wt%, B: 0.8 to 2.0 in B(wt%)/N(wt%), the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000°C, or at a state that the slab is reheated to higher than 1000°C from a temperature range where the slab has a surface temperature of not lower than 600°C and is soaked for more than 10 min, coiling at temperature of more than 650°C following accomplishing at finishing temperature of more than 820°C, subjecting a cold rolling of once to the hot rolled steel strip or cold rollings of more than twice interposing a process annealing thereto, and continuously annealing serving as a decarburization annealing at a range between temperatures of 750 and 950°C, thereby to decrease the C content less than 0.005 wt%.
0.1 to 1.5 wt%, Mn: 0.1 to 1.0 wt%, S: less than 0.005 wt%, Al:
not more than 0.005 wt%, P: not more than 0.1 wt%,N: not more than 0.0030 wt%, B: 0.8 to 2.0 in B(wt%)/N(wt%), the balance being Fe and unavoidable impurities, at a state that the surface temperature of the slab is not lower than 1000°C, or at a state that the slab is reheated to higher than 1000°C from a temperature range where the slab has a surface temperature of not lower than 600°C and is soaked for more than 10 min, coiling at temperature of more than 650°C following accomplishing at finishing temperature of more than 820°C, subjecting a cold rolling of once to the hot rolled steel strip or cold rollings of more than twice interposing a process annealing thereto, and continuously annealing serving as a decarburization annealing at a range between temperatures of 750 and 950°C, thereby to decrease the C content less than 0.005 wt%.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP39214 | 1989-02-21 | ||
| JP3921489 | 1989-02-21 | ||
| JP342,206 | 1989-12-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2010586A1 true CA2010586A1 (en) | 1990-08-21 |
Family
ID=12546886
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002010586A Abandoned CA2010586A1 (en) | 1989-02-21 | 1990-02-21 | Method of making non-oriented magnetic steel strips |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2010586A1 (en) |
-
1990
- 1990-02-21 CA CA002010586A patent/CA2010586A1/en not_active Abandoned
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3636579A (en) | Process for heat-treating electromagnetic steel sheets having a high magnetic induction | |
| EP0947597B2 (en) | Method of producing a grain-oriented electrical steel sheet excellent in magnetic characteristics | |
| CA1318576C (en) | Method of making non-oriented silicon steel sheets having excellent magnetic properties | |
| US5833768A (en) | Grain-oriented electrical steel sheet with very low core loss and method of producing the same | |
| KR950013287B1 (en) | Method of making non-viented magnetic steel strip | |
| US5108521A (en) | Method of making non-oriented magnetic steel strips | |
| US7887645B1 (en) | High permeability grain oriented electrical steel | |
| CN115747650B (en) | A kind of low temperature high magnetic induction grain oriented silicon steel and the method for improving its magnetic property stability | |
| US5139582A (en) | Method of manufacturing an oriented silicon steel sheet having improved magnetic characeristics | |
| EP0527495B1 (en) | Method of producing non-oriented electrical steel sheet having good magnetic properties | |
| CA2033059C (en) | Process for producing grain oriented silicon steel sheets having excellent magnetic properties | |
| US5169457A (en) | Method of making non-oriented electrical steel sheets | |
| US4371405A (en) | Process for producing grain-oriented silicon steel strip | |
| CA2010586A1 (en) | Method of making non-oriented magnetic steel strips | |
| EP0551141A1 (en) | Oriented magnetic steel sheets and manufacturing process therefor | |
| KR100347597B1 (en) | Manufacturing method of high magnetic flux density oriented electrical steel sheet | |
| EP0392535B2 (en) | Process for preparation of grain-oriented electrical steel sheet having superior magnetic properties | |
| JPH0629461B2 (en) | Method for producing silicon steel sheet having good magnetic properties | |
| KR960006025B1 (en) | Manufacturing method of high magnetic flux density oriented electrical steel with excellent magnetic properties | |
| JP2653948B2 (en) | Preparation of Standard Grain Oriented Silicon Steel without Hot Strip Annealing | |
| CN119530648A (en) | A high-grade non-oriented silicon steel with a high proportion of favorable texture and a production method thereof | |
| JPH0387316A (en) | Production of grain-oriented silicon steel sheet having stable magnetic property | |
| KR100256343B1 (en) | The manufacturing method for oriented electric steel sheet with low temperature heating type | |
| JPH03249130A (en) | Production of nonoriented silicon steel sheet | |
| JPH09194940A (en) | Method for manufacturing unidirectional electrical steel sheet |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |