JP3580013B2 - Hot rolling method of slab for electrical steel sheet - Google Patents

Description

【００２６】
同表から明らかなように、この発明に従う条件下で熱間圧延を実施した場合には、磁気特性および表面性状ともに良好であったが、比較例においては張力付与、絶縁性の機能を兼ねるグラス皮膜に、熱延板スケールに起因する欠陥（点状の皮膜剥離）が顕著にみられ、また磁気特性にも劣っていた。
【００２７】
実施例２
Ｃ：０．００５ ｗｔ％、Ｓｉ：３．０ ｗｔ％、Ｍｎ：０．１５ｗｔ％、Ａｌ：０．３ ｗｔ％およびＰ：０．０１ｗｔ％を含有し、残部は実質的にＦｅの組成になる電磁鋼スラブ（鋼Ａ、厚み ２２０ｍｍ）ならびにＣ：０．００４ ｗｔ％、Ｓｉ：１．５ ｗｔ％、Ｍｎ：０．３０ｗｔ％、Ａｌ：０．３ ｗｔ％およびＰ：０．０１ｗｔ％を含有し、残部は実質的にＦｅの組成になる電磁鋼スラブ（鋼Ｂ、厚み ２２０ｍｍ）をそれぞれ、通常のガス燃焼型加熱炉にて１２００℃に加熱後、熱間粗圧延を行って５５ｍｍ厚のシートバーとした。このとき、ロールベンディング量および縦ロールでの水平圧下量を制御して、シートバー断面形状を調整した。ついで、このシートバーを巻取り開始径を ０．３ｍとして巻取った後、再び巻戻して仕上圧延により板厚：２．６ ｍｍの熱延板とした。
ついで、鋼Ａは熱延板焼鈍後、また鋼Ｂは熱延板焼鈍を施さずに、冷間圧延により０．５０ｍｍに仕上げたのち、 ８５０℃， ３０秒の連続焼鈍を施した。
かくして得られた製品の磁気特性および表面性状について調査した結果を表２に示す。
【００２８】
【表２】

【００２９】
同表から明らかなように、この発明の要件を満足する条件下で熱間圧延を実施した場合は、磁気特性および表面性状とも良好であったが、比較例においては熱延前の表面割れが熱延、冷延によって引き延ばされた線状の欠陥（ヘゲ）が顕著に見られた。
【００３０】
実施例３
Ｃ：０．００２ ｗｔ％、Ｓｉ：０．６５ｗｔ％、Ｍｎ：０．２０ｗｔ％、Ａｌ：０．７０ｗｔ％およびＰ：０．０７ｗｔ％を含有し、残部は実質的にＦｅの組成になる電磁鋼スラブ（鋼Ａ、厚み ２２０ｍｍ）ならびにＣ：０．００２ ｗｔ％、Ｓｉ：０．３５ｗｔ％、Ｍｎ：０．２５ｗｔ％、Ａｌ：０．２５ｗｔ％およびＰ：０．０５ｗｔ％を含有し、残部は実質的にＦｅの組成になる電磁鋼スラブ（鋼Ｂ、厚み ２２０ｍｍ）をそれぞれ、通常のガス燃焼型加熱炉にて１２００℃に加熱後、熱間粗圧延を行って２０ｍｍ厚のシートバーとした。このとき、ロールベンディング量および縦ロールでの水平圧下量を制御して、シートバー断面形状を調整した。ついで、このシートバーを巻取り開始径を １．８ｍとして巻取った後、再び巻戻しながら仕上圧延中の先行シートバーの後端部に接合し、連続仕上圧延により板厚：２．４ ｍｍの熱延板とした。
ついで、鋼Ａは熱延板焼鈍後、また鋼Ｂは熱延板焼鈍を施さずに、冷間圧延により板厚：０．５３ｍｍの冷延板としたのち、 ７５０℃， ３０秒の連続焼鈍を施した。その後、スキンパスにより、０．５０ｍｍの最終板厚に仕上げた。
かくして得られた製品に ７５０℃， ２ｈの歪取り焼鈍を施した後、磁気特性および表面性状について調査した結果を表３に示す。
【００３１】
【表３】

【００３２】
同表から明らかなように、この発明に従う条件下で熱間圧延を実施した場合には、磁気特性および表面性状は共に良好であったが、比較例においてはスケールの残存に起因する表面欠陥（凹凸）が顕著に見られた。このようなスケール残りによる凹凸は製品の占積率を低下させるだけでなく、鋼板の打抜性に悪影響を及ぼす。
【００３３】
【発明の効果】
かくして、この発明によれば、熱間粗圧延後におけるシートバー巻取り時に、表面割れのおそれなしに生成スケールを効果的に剥離することができ、従って、磁気特性に優れるのは言うまでもなく、スケール残留や表面割れに起因した表面欠陥のない美麗表面の電磁鋼板を安定して得ることができる。
【図面の簡単な説明】
【図１】Ｈ_ｅ −Ｈ＝０の場合における、スケールの残存量に及ぼすシートバー厚みＨと巻取り径Ｄとの関係を示したグラフである。
【図２】Ｈ_ｅ −Ｈ＝１．０ の場合における、スケールの残存量に及ぼすシートバー厚みＨと巻取り径Ｄとの関係を示したグラフである。
【図３】Ｈ_ｅ −Ｈ＝３．０ の場合における、スケールの残存量に及ぼすシートバー厚みＨと巻取り径Ｄとの関係を示したグラフである。
【図４】Ｈ_ｅ −Ｈ＝５．０ の場合における、スケールの残存量に及ぼすシートバー厚みＨと巻取り径Ｄとの関係を示したグラフである。
【図５】Ｈ_ｅ −Ｈ＝７．０ の場合における、スケールの残存量に及ぼすシートバー厚みＨと巻取り径Ｄとの関係を示したグラフである。
【図６】スケールの残存量に及ぼすシートバー厚みと巻取り径との関係を示したグラフである。
【図７】表面欠陥の発生状況をシートバー厚みと巻取り径との関係で示したグラフである。
【図８】シートバー巻取り時における板剤の湾曲状態を示した模式図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for hot rolling a slab for an electromagnetic steel sheet, and more particularly to improving magnetic properties and surface properties.
Further, the present invention is applicable to any manufacturing of so-called electromagnetic steel sheets, regardless of whether they are non-oriented electrical steel sheets or oriented electrical steel sheets.
[0002]
[Prior art]
Electrical steel sheets are used as iron core materials for motors, generators, transformers, and the like, and are broadly classified into grain-oriented electrical steel sheets and non-oriented electrical steel sheets. In any case, in order to increase the energy efficiency of these devices, it is necessary that the magnetic properties include a small iron loss and a high magnetic flux density.
By the way, in recent years, as the accuracy of these devices has increased, the electromagnetic steel sheet as a material has been required to have less variation in magnetic properties and plate shape, and particularly to be uniform in a product coil. It has become.
In addition, in order to have a high space factor at the time of lamination and to stabilize device characteristics by high interlayer insulating properties, sufficient consideration is required for surface properties.
[0003]
[Problems to be solved by the invention]
As a factor of characteristic instability in the product coil, there is a temperature fluctuation during hot rolling. As a solution to this problem, JP-A-57-109504, JP-A-61-38703 and JP-A-62-248501 disclose that a sheet bar after hot rough rolling is once wound around a coil. Thereafter, a method of preventing the temperature at the rear end portion from lowering by rolling while unwinding has been proposed.
[0004]
However, when such a method is applied to a slab containing Si such as for an electromagnetic steel sheet, since the holding time at a high temperature by winding and unwinding the sheet bar is long, the peelability of the generated scale is poor. However, there remains a problem in that the surface properties of the product are significantly deteriorated.
If this scale is to be removed with a high-pressure water descaler or a roll-type mechanical descaler, which is usually performed before hot rolling, only the amount of water and the pressing force of the roll are required more than ordinary steel. Nevertheless, the scale still remained partially, and the deterioration of characteristics and the deterioration of the surface properties due to heat removal were inevitable.
[0005]
[Means for Solving the Problems]
The present invention advantageously solves the above-described problem, and even when the sheet bar is wound up after hot rough rolling and the unwinding process is performed, the scale is effectively peeled off, and the remaining scale is removed. An object of the present invention is to propose a novel hot rolling method for a slab for an electromagnetic steel sheet, which does not cause deterioration of the surface properties due to the slab.
[0006]
That is, the present invention
C: 0.0001-0.1 wt%,
Si: 0.05-4.5 wt%,
When subjecting a slab for magnetic steel sheet containing Mn: 2.5 wt% or less to hot rolling including rough rolling and finish rolling,
The sheet bar of the cross-sectional shape after rough rolling H <H _e ≦ H + 5
Where H: Sheet bar center thickness (mm)
H _e: sheet bar ends Thickness (mm)
And the relationship
H / 100 ≦ D ≦ H / 30 + 2
Where D: sheet bar winding diameter (m) from winding start to winding end
A hot rolling method for a slab for an electromagnetic steel sheet, wherein the slab is wound around a coil under conditions that satisfy the following conditions and then unwound and subjected to finish rolling.
[0007]
Further, in the present invention, after the hot rough rolling, the wound and unwound sheet bar can be connected to the rear end of the preceding sheet bar during the finish rolling to perform the finish rolling continuously.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be specifically described based on the experimental results that led to the present invention.
Experiment 1
C: 0.005 wt%, Si: 0.55 wt%, Mn: 0.50 wt%, Al: 0.03 wt%, and P: 0.01 wt%, and the balance is substantially Fe. A steel slab (thickness: 220 mm) is heated to 1150 ° C. in a normal gas-fired heating furnace, then made into a sheet bar by hot rough rolling, wound up in a coil, unwound after heat retention, and finished rolled. To obtain a hot-rolled sheet having a thickness of 2.0 mm.
At this time, the sheet bar thickness, H = 10, 20, 30 , 40, 50, 60mm and, respectively to adjust the horizontal rolling reduction in the roll bending amount and vertical rolls, the cross-sectional shape of the sheet bar _H e -H = 0, 1.0, 3.0, 5.0, 7.0 (mm)
Where H: sheet bar center thickness (mm)
H _e: sheet bar ends Thickness (mm)
And
In winding the sheet bar, the winding start diameter was changed to 1, 2, 3, 4 m.
[0009]
The coil after the finish hot rolling was sampled by dividing it in the longitudinal direction, and the winding diameter of the sheet bar was determined based on the sampling position.
Further, the scale of the steel sheet surface after being immersed in 10% sulfuric acid at 80 ° C. for 5 minutes was examined and used as an index of the remaining amount of the scale.
1 to 5 show the results of investigations on the relationship between the sheet bar thickness and the winding diameter that affect the remaining amount of scale.
[0010]
As apparent from the figure, the sheet bar winding diameter is small and the sheet bar thickness is too large scale remaining amount is small, especially 0 <H _e -H when the ≦ 5, dotted following areas in the figure ( D ≦ H / 30 + 2), it was found that the amount of remaining scale was significantly reduced.
[0011]
Experiment 2
C: 0.01 wt%, Si: 1.3 wt%, Mn: 0.2 wt%, Al: 0.05 wt% and P: 0.03 wt%, the balance being an electromagnetic steel slab (thickness: 220 mm) substantially consisting of Fe Is heated to 1100 ° C. in a normal gas-fired heating furnace, then made into a sheet bar by hot rough rolling, wound around a coil, unwound again after heat retention, and subjected to finish rolling to a 1.8 mm thick heat. It was a rolled sheet.
At this time, the sheet bar thickness was changed to H = 20, 30, 40, 50, 60, 70 , and 80 mm, while the winding start diameter was fixed at 0.3 m.
The cross-sectional shape of the sheet bar was a constant _{H e -H = 1.0 (mm)} .
[0012]
The coil after the finish hot rolling was sampled by dividing it in the longitudinal direction, and the winding diameter of the sheet bar was determined based on the sampling position.
Further, the scale of the steel sheet surface after being immersed in 10% sulfuric acid at 80 ° C. for 5 minutes was examined and used as an index of the remaining amount of the scale.
FIG. 6 summarizes the results of an investigation on the relationship between the sheet bar thickness and the winding diameter that affect the remaining amount of scale.
According to the figure, it was found that the amount of remaining scale was very small and good under all conditions.
[0013]
However, in Experiment 2, a surface defect (scab) was observed, which was not observed at all in Experiment 1 and is considered to be caused by cracks before hot rolling.
Then, the occurrence state of such surface defects was investigated next.
FIG. 7 shows the occurrence of surface defects in relation to the sheet bar thickness and the winding diameter.
According to the figure, the occurrence of surface defects is more remarkable as the sheet bar winding diameter is smaller and the sheet bar is thicker, but it is not generated at all in the region ( D ≧ H / 100) above the dotted line in the figure. found.
[0014]
From the results of Experiments 1 and 2 described above, in order to effectively descaling the scale generated when winding the sheet bar after rough rolling before the finish hot rolling, and not to generate surface defects due to cracks, the sheet bar of the cross-sectional shape after rough rolling H <H _e ≦ H + 5
And, over the entire period from the start of winding to the end of winding,
H / 100 ≦ D ≦ H / 30 + 2
It has been found that it is only necessary to wind up under conditions that satisfy the conditions.
[0015]
The reason why the above-described effects can be obtained by winding the sheet bar under the conditions satisfying the above formula according to the present invention is considered as follows.
That is, the scale generated on the surface of the sheet bar is mechanically peeled off due to the deformation of the sheet bar during winding and rewinding of the sheet bar. Substantially, this is considered to be an effect similar to that of a conventional roll pressing mechanical descaler.
However, in the case of the present invention, since it is not necessary to press the roll or spray high-pressure water, there is an advantage in that the temperature of the plate is less reduced.
[0016]
FIG. 8 schematically shows a state in which the plate material is curved at the time of winding the sheet bar.
As shown in the drawing, the outside of the sheet bar having the length AB due to the curvature of the sheet bar becomes A'B '(> AB), and the inside becomes A "B"(<AB). Elongation and shrinkage on the bar front and back contribute to peeling.
The expansion and contraction increase as the sheet bar thickness H increases and the radius of curvature D / 2 decreases. That is, the scale releasability is improved.
On the other hand, if the curve is made larger than necessary for scale peeling, a large tensile stress is applied to the vicinity of the surface layer on the front and back surfaces during winding and rewinding, and fine grain boundary cracks occur. It is considered that the film is stretched by the process to become a surface defect.
[0017]
If the sheet bars come into contact with each other and the surface pressure is applied during the winding of the sheet bar, the scale generated on the sheet bar surface will bite into the base steel part due to the surface pressure, and the scale will be more difficult to peel.
In this respect, if H <H _e, because sheet bars each other during winding is in contact only at the end, since the locations other than the end portion surface pressure not applied in substantial scale bites into the base steel part And therefore easily peeled off. Nevertheless, the H _e is larger than the H + 5, although the surface pressure is not applied, the gap of the sheet bar comrades increases during winding, from the atmosphere (substantially atmospheric) becomes much be encapsulated, thereby It is considered that the remaining amount of scale increases because additional scale is generated.
Therefore, in order to reduce the amount of residual scale and to prevent surface defects due to grain boundary cracks, it is important to control the cross-sectional shape, thickness and winding diameter of the sheet bar within the appropriate ranges described above according to the present invention. is there.
[0018]
Next, the reason why the component composition of the material is limited to the above range in the present invention will be described.
C: 0.0001-0.1 wt%
When manufacturing a grain-oriented electrical steel sheet, 0.01 wt% or more is necessary to promote the refinement of the microstructure of the hot-rolled sheet, but if it exceeds 0.1 wt%, the load in decarburization annealing is large. In addition, C remaining in the product is not preferable because it induces aging deterioration of magnetic properties.
On the other hand, in the production of non-oriented electrical steel sheets, the content needs to be 0.01% by weight or less in order to prevent aging deterioration of products. The lower limit is set to 0.0001 wt% for economic reasons.
[0019]
Si: 0.05 to 4.5 wt%
Si is an element useful for increasing electric resistance and improving iron loss. However, if added in excess of 4.5 wt%, cold rollability is deteriorated, so the upper limit is 4.5 wt%. I do.
When the grain-oriented electrical steel sheet is still produced, if the content is less than 2 wt%, secondary recrystallization is hindered by randomization of the texture due to austenite transformation, so the lower limit is preferably 2 wt%.
In this regard, in the case of a non-oriented electrical steel sheet, it is not necessary to set a lower limit in particular because secondary recrystallization is not performed, but the lower limit is set to 0.05 wt% in order to improve iron loss.
[0020]
Mn: 2.5 wt% or less Mn is a useful element for improving hot workability. However, if it exceeds 2.5 wt%, the amount of transformation increases and magnetic deterioration occurs. Is the upper limit.
[0021]
Although the essential components have been described above, various other known elements can be added.
For example, in a grain-oriented electrical steel sheet, Al, P, Cr, B, Se, S, Te, Nb, Bi, Sn, Sb, N, Mo, or the like can be added as an inhibitor component.
In the Nakata countercurrent electrical steel sheet, it can be added Al, B, Sb, Ni, Cu and Sn, as the magnetic properties improve component.
[0022]
Next, a manufacturing method will be described.
The steel slab adjusted to the above-mentioned preferable component composition is subjected to a rolling treatment as necessary and subjected to slab heating or directly subjected to rough rolling after casting.
In the present invention, after the rough rolling, the sheet bar is once wound into a coil, and after heat retention, the sheet bar is rewound and subjected to finish annealing.
H / 100 ≦ D ≦ H / 30 + 2
It is important to carry out under conditions that satisfy the following.
When the unwound sheet bar is subjected to finish rolling, continuous processing by joining the leading end of the succeeding sheet bar to the trailing end of the preceding sheet bar is particularly desirable from the viewpoint of improving operating efficiency. It is advantageous.
[0023]
After the hot rolling, the non-oriented electrical steel sheet is subjected to one or two or more cold rollings according to a conventional method, and then subjected to finish annealing to obtain a product sheet.
In addition, for grain-oriented electrical steel sheets, this is also subjected to cold rolling one or more times according to a conventional method, followed by decarburization and primary recrystallization annealing, and then applying an annealing separating agent, A secondary recrystallization annealing and a final finish annealing are performed to obtain a product plate.
[0024]
【Example】
Example 1
C: 0.05 wt%, Si: 3.3 wt%, Mn: 0.08 wt%, Se: 0.015 wt%, Al: 0.025 wt%, and N: 0.008 wt%, with the balance being the balance After heating an electromagnetic steel slab (thickness 220 mm) substantially having a Fe composition to 1200 ° C. in a normal gas-fired heating furnace, and then to a high temperature of 1410 ° C. in an induction heating electric furnace, Rough rolling was performed to obtain a sheet bar having a thickness of 30 mm. At this time, the cross-sectional shape of the sheet bar was adjusted by controlling the roll bending amount and the horizontal reduction amount by the vertical roll. Next, the sheet bar was wound with a winding start diameter of 2.0 m, and was rewound again to obtain a hot-rolled sheet having a thickness of 2.0 mm by finish rolling.
Then, after the hot-rolled sheet annealing, the sheet was finished to a final sheet thickness of 0.23 mm by two cold rolling steps with intermediate annealing. Thereafter, after decarburization and primary recrystallization annealing were performed in a humid atmosphere, an annealing separator containing MgO 2 as a main component was applied, and then final finishing annealing was performed at 1200 ° C. for 10 hours in a dry hydrogen atmosphere. .
Table 1 shows the results of an investigation on the magnetic properties and surface properties of the product thus obtained.
Note that the sheet bar winding diameter was determined from the radius of curvature at the time of winding the sheet bar calculated based on the sampling position.
[0025]
[Table 1]

[0026]
As is clear from the table, when hot rolling was performed under the conditions according to the present invention, both the magnetic properties and the surface properties were good, but in the comparative example, the glass having both functions of imparting tension and insulating properties was used. Defects (dot-like film peeling) caused by the scale of the hot rolled sheet were remarkably observed in the film, and the magnetic properties were also poor.
[0027]
Example 2
C: 0.005 wt%, Si: 3.0 wt%, Mn: 0.15 wt%, Al: 0.3 wt%, and P: 0.01 wt%, and the balance is substantially Fe composition. Slab (steel A, thickness 220 mm) and C: 0.004 wt%, Si: 1.5 wt%, Mn: 0.30 wt%, Al: 0.3 wt% and P: 0.01 wt%. The remaining steel slab (steel B, thickness 220 mm) having a composition of substantially Fe is heated to 1200 ° C. in a normal gas-fired heating furnace, and then hot-rolled to a thickness of 55 mm. Sheet bar. At this time, the cross-sectional shape of the sheet bar was adjusted by controlling the roll bending amount and the horizontal reduction amount by the vertical roll. Subsequently, the sheet bar was wound with a winding start diameter of 0.3 m, and was rewound again to obtain a hot-rolled sheet having a sheet thickness of 2.6 mm by finish rolling.
Then, steel A was hot-rolled sheet-annealed, and steel B was not subjected to hot-rolled sheet annealing, but was finished to 0.50 mm by cold rolling and then subjected to continuous annealing at 850 ° C. for 30 seconds.
Table 2 shows the results of investigation on the magnetic properties and surface properties of the products thus obtained.
[0028]
[Table 2]

[0029]
As is clear from the table, when hot rolling was performed under the conditions satisfying the requirements of the present invention, both the magnetic properties and the surface properties were good, but in the comparative example, surface cracks before hot rolling were observed. Remarkable linear defects (scabs) elongated by hot rolling and cold rolling were observed.
[0030]
Example 3
C: 0.002 wt%, Si: 0.65 wt%, Mn: 0.20 wt%, Al: 0.70 wt%, and P: 0.07 wt%, and the balance is substantially Fe. Contains steel slab (steel A, thickness 220 mm) and C: 0.002 wt%, Si: 0.35 wt%, Mn: 0.25 wt%, Al: 0.25 wt% and P: 0.05 wt%, with the balance being the balance Are heated to 1200 ° C. in a normal gas-fired heating furnace, and then subjected to hot rough rolling to form a 20 mm-thick sheet bar with a magnetic steel slab (steel B, thickness 220 mm) substantially having a Fe composition. did. At this time, the cross-sectional shape of the sheet bar was adjusted by controlling the roll bending amount and the horizontal reduction amount by the vertical roll. Then, after winding the sheet bar at a winding start diameter of 1.8 m, the sheet bar is joined to the rear end of the preceding sheet bar during finish rolling while being unwound again, and the sheet thickness is 2.4 mm by continuous finish rolling. Hot rolled sheet.
Then, steel A was subjected to hot-rolled sheet annealing, and steel B was not subjected to hot-rolled sheet annealing, but was cold-rolled into a cold-rolled sheet having a thickness of 0.53 mm, and then continuously annealed at 750 ° C. for 30 seconds. Was given. Then, it was finished to a final thickness of 0.50 mm by a skin pass.
Table 3 shows the results obtained by subjecting the thus obtained product to strain relief annealing at 750 ° C. for 2 hours and then examining the magnetic properties and surface properties.
[0031]
[Table 3]

[0032]
As is clear from the table, when hot rolling was performed under the conditions according to the present invention, both the magnetic properties and the surface properties were good, but in the comparative example, the surface defects ( Remarkably). Such unevenness due to the remaining scale not only lowers the space factor of the product, but also adversely affects the punching performance of the steel sheet.
[0033]
【The invention's effect】
Thus, according to the present invention, at the time of winding the sheet bar after hot rough rolling, the formed scale can be effectively peeled off without fear of surface cracking, and therefore, needless to say, the scale is excellent in magnetic properties. It is possible to stably obtain an electromagnetic steel sheet having a beautiful surface without surface defects caused by residual or surface cracks.
[Brief description of the drawings]
[1] in the case of H _e -H = 0, it is a graph showing the relationship between the sheet bar thickness H and the winding diameter D on the residual amount of the scale.
In the case of FIG. 2 H _e -H = 1.0, is a graph showing the relationship between the sheet bar thickness H and the winding diameter D on the residual amount of the scale.
[3] in the case of H _e -H = 3.0, it is a graph showing the relationship between the sheet bar thickness H and the winding diameter D on the residual amount of the scale.
In the case of FIG. 4 H _e -H = 5.0, is a graph showing the relationship between the sheet bar thickness H and the winding diameter D on the residual amount of the scale.
[5] in the case of H _e -H = 7.0, it is a graph showing the relationship between the sheet bar thickness H and the winding diameter D on the residual amount of the scale.
FIG. 6 is a graph showing the relationship between the thickness of the sheet bar and the winding diameter that affects the remaining amount of the scale.
FIG. 7 is a graph showing a state of occurrence of surface defects in a relationship between a sheet bar thickness and a winding diameter.
FIG. 8 is a schematic diagram illustrating a curved state of a plate material during winding of a sheet bar.

Claims (2)

C: 0.0001-0.1 wt%,
Si: 0.05-4.5 wt%,
When subjecting a slab for magnetic steel sheet containing Mn: 2.5 wt% or less to hot rolling including rough rolling and finish rolling,
The sheet bar of the cross-sectional shape after rough rolling H <H _e ≦ H + 5
Where H: Sheet bar center thickness (mm)
H _e: sheet bar ends Thickness (mm)
And the relationship
H / 100 ≦ D ≦ H / 30 + 2
Where D: sheet bar winding diameter (m) from winding start to winding end
A method for hot rolling a slab for an electromagnetic steel sheet, comprising winding a coil under a condition satisfying the following, followed by rewinding and subjecting the slab to finish rolling. 2. The electromagnetic device according to claim 1, wherein after the hot rough rolling, the wound and unwound sheet bar is connected to the rear end of the preceding sheet bar during the finish rolling, and the finish rolling is continuously performed. Hot rolling method of slab for steel plate.

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