JP5423629B2 - Method for producing non-directional electromagnetic hot-rolled steel strip with high magnetic flux density - Google Patents

Description

  The present invention relates to a method for producing a non-directional electromagnetic hot-rolled steel strip having a high magnetic flux density, which is used as an iron core material for electrical equipment. In particular, the present invention relates to a method for producing a non-directional electromagnetic hot-rolled steel strip that can omit the cold rolling and recrystallization annealing steps and has a low production cost.

  In recent years, due to increasing awareness of global environmental issues such as global warming, rotating machines, compressors and medium, small transformers, reactors, etc. that use non-directional electromagnetic hot-rolled steel strips have been incorporated. Efficiency regulations are being implemented in equipment. For this reason, even in applications where low grade non-oriented electromagnetic hot-rolled steel strips have been used, there is a growing trend to use middle grade and high grade non-oriented electrical steel sheets with lower iron loss. For this reason, the request | requirement to high magnetic flux density and low iron loss is stronger than the past with respect to a non-oriented electrical steel sheet.

  The reduction of iron loss in non-oriented electrical steel sheets is mainly achieved by reducing the Joule heat loss caused by the eddy current generated in each steel sheet when the iron core is excited by increasing the electrical resistivity by adding Si and Al. I came. Also, for the same purpose, eddy current loss has been reduced by reducing the plate thickness and shortening the path through which eddy current flows.

  Further, in order to reduce the loss of various devices in which the non-oriented electrical steel sheet is used, it is also important to reduce the copper loss, which is the Joule heat loss caused by the exciting current flowing in the coil that magnetizes the non-oriented electrical steel sheet. In order to reduce the copper loss, a material that expresses a higher magnetic flux density with a lower excitation current is required.

  For this purpose, it is essential to develop a non-oriented electrical steel sheet having a high magnetic flux density by controlling the texture of the non-oriented electrical steel sheet. Since the magnetization of the iron core becomes stronger by improving the magnetic flux density, it is possible to reduce the size of the iron core, and in a rotating machine, the torque is increased and the size and output can be increased. Thus, by using a high magnetic flux density non-oriented electrical steel sheet, there is an advantage that a rotating machine, a transformer, and the like can be reduced in size and weight. Further, in the magnetic shield, the shielding property is enhanced, and at the same time, the shield can be thinned.

  Conventionally, elements with high electrical resistivity, such as Si and Al, which have been mainly added to low iron loss non-oriented electrical steel sheets, decrease the saturation magnetic flux density as the content increases. First, as a result, the iron core size is increased, and there is a problem that the rotating machine, the transformer, and the like are enlarged.

  On the other hand, in the high magnetic flux density non-directional electromagnetic hot-rolled steel strip disclosing its manufacturing method in the present invention, it is possible to reduce the size of both the rotating machine and the iron core by improving the magnetic flux density. Such a moving body has an advantage that energy loss during operation can be reduced by reducing the weight of the entire system.

  Thus, by realizing a high magnetic flux density non-directional electromagnetic hot-rolled steel strip, not only can the copper loss during operation of the iron core and rotating machine be reduced, but also contribute to downsizing, as well as the overall equipment including it. There is also a great ripple effect on the system.

  On the other hand, in order to compete with cheap non-oriented electrical steel sheets supplied from emerging countries, it is an urgent issue to reduce manufacturing costs, and a manufacturing method that is much cheaper than the conventional non-oriented electrical steel sheet manufacturing method The development of was demanded. In addition, the demand for cost reduction among customers who use non-oriented electrical steel sheets is increasing during the times of great competition with foreign countries, and customers also have non-directionality with low cost and superior magnetic properties. Development of a method for manufacturing electrical steel sheets has been demanded.

  As a method for solving this problem, a thin slab manufacturing process with a small capital investment has been attracting attention.

  Hereinafter, the non-oriented electrical steel sheet manufactured by the present invention is referred to as a non-oriented electromagnetic hot-rolled steel strip or electromagnetic hot-rolled steel strip, and after the hot-rolled electrical steel sheet or cold-rolling process according to the prior art, in the finish annealing process Differentiate from non-oriented electrical steel sheets or cold-rolled electrical steel sheets that obtain recrystallized structure.

  Here, the principle of improving the magnetic properties of the non-oriented electrical steel sheet will be described.

  In bcc iron used in non-oriented electrical steel sheets, the <100> direction of the crystal unit cell coincides with the easy axis of magnetization. Therefore, in the texture of the non-oriented electrical steel sheet, the random cube orientation in which the easy axis of bcc iron exists in the plate surface where the magnetic flux flows is considered ideal. This is expressed as {100} <0vw> using Miller indices, where v and w are arbitrary indices. In general, a crystal orientation having two <100> axes in a plate surface is called a cube orientation.

  However, in the texture of non-oriented electrical steel sheets obtained by ordinary cold rolling and recrystallization annealing, a gamma fiber texture with the <111> axis coincided with the normal direction of the plate surface has developed, and the ideal cube orientation exists. Is slight.

  On the other hand, in recent years, in Patent Document 1, non-directionality having a random cube texture obtained by subjecting a thin cast slab having an αγ transformation of 4% or more to low cold rolling of 5% or more and 40% or less. A method for manufacturing electrical steel sheets has been disclosed.

  In this prior application, the technical idea is to use columnar crystals formed during the casting of a thin slab. That is, the columnar crystals developed in the solidified structure of the thin slab coincide with the <100> axis of the crystal in the normal direction of the plate surface that is the growth direction, so the <100> axes in the other two directions are within the plate surface. It has a cube orientation that is favorable for the properties of the non-oriented electrical steel sheet.

  In this technology, the thin slab is cold-rolled at a rolling rate within a certain range, and the crystal grains in the cube orientation are grown during finish annealing with the columnar crystals formed in the thin slab during solidification. The technical idea is to improve the magnetic properties of the non-oriented electrical steel sheet by enriching the cube orientation of the product after finish annealing.

  In this prior application, the Si content is 4% or more, and no αγ transformation occurs in the α single phase from solidification to room temperature. For this reason, orientation randomization due to transformation between the α phase and γ layer formed during solidification does not occur, and columnar crystals having a cube orientation formed during solidification are effectively utilized, and there is no cubic orientation. A grain-oriented electrical steel sheet can be manufactured.

  On the other hand, in this prior application, since the cold rolling rate applied from the solidified slab to the final plate thickness is limited to a small range of 5% or more and less than 40%, there is no room for shape correction of the steel strip by cold rolling. There is a problem that there are few. This is because non-oriented electrical steel sheets are used by being laminated to form an iron core, and therefore require higher plate thickness accuracy than automobile steel sheets and the like.

  In Patent Document 2, molten steel having a Si content of 4% or less is directly and continuously cast, and the thickness of the thin cast slab is 30 mm or more and 140 mm or less. A method for manufacturing a non-oriented electrical steel sheet is disclosed in which a strip is used and the final sheet thickness is 30% to 85%.

  In this prior application, in order to make a hot-rolled steel strip by hot rolling using a thin slab whose thickness is usually thinner than a continuous cast slab of about 200 mm, the rolling reduction from the solidified slab to the hot-rolled steel strip is It can be lowered.

  Therefore, the technical idea is to improve the magnetic properties by controlling the texture after rolling and recrystallization by increasing the residual rate in the hot rolled steel strip of columnar crystals with cube orientation developed in thin cast slabs. Yes.

  In this prior application, columnar crystals having a cube orientation developed in a thin slab are likely to change to another orientation due to recrystallization during subsequent hot rolling, so it is difficult to control the remaining ratio of the cube orientation. There was a problem that the magnetic characteristics of the product were likely to be unstable.

  Moreover, in this prior application, since the hot-rolled steel strip was cold-rolled and subjected to finish annealing, there was a problem that the cost increased.

  Patent Document 3 discloses a casting method in which a strip having a thickness of 5 mm or less is continuously cast by a twin roll casting method or the like, and the cooling speed is controlled. Patent Document 4 discloses that a strip having a thickness of 5 mm is continuously cast by a cooling casting roll. However, a technique for subjecting the strip to hot rolling and rolling at least 15% is disclosed.

  Further, -Patent Document 5 discloses a method for controlling cooling after casting a thin strip having a thickness of 2 mm or less, for example.

Patent Document 6 discloses a method for stably casting a thin strip by controlling the oxide composition of MnO, SiO2, and Al2O3 in steel.

  However, when the solidified strip is a thin strip of 5 mm or less, even if at least 15% hot rolling is applied, there is little room for texture control of the hot-rolled steel strip by controlled hot rolling until the final thickness is reached. It is difficult to obtain a high magnetic flux density non-directional electromagnetic hot-rolled steel strip.

  Furthermore, if the thickness of the solidified strip is 5mm or less, there is little room for straightening the thickness to the final thickness by finishing hot rolling, and it is difficult to improve the thickness accuracy, which is necessary for non-directional electromagnetic hot-rolled steel strips. There is a problem that it is difficult to obtain the plate thickness accuracy.

  Patent Document 7 discloses a technique for rolling up a sheet bar after rough rolling, soaking it, and performing finish rolling as a method for producing a hot rolled electrical steel sheet. However, since the technical idea of this manufacturing method promotes recrystallization of the hot-rolled steel sheet during finish rolling, the recrystallized texture becomes γ fiber in bcc iron, and the magnetic flux density decreases.

  In addition, since the obtained hot-rolled electrical steel sheet is annealed in the embodiment of this prior application, the gamma fiber that is the main orientation further develops with the growth of crystal grains during annealing, and the magnetic flux density further decreases. .

  As described above, conventional thin slab manufacturing equipment or hot rolled electrical steel sheet manufacturing methods are not optimized for the manufacturing process of non-oriented electromagnetic hot rolled steel sheets, and there is much room for improvement. The high magnetic flux density non-oriented electromagnetic hot-rolled steel sheet, which is strong, low-cost, and advantageous for downsizing the iron core, could not be manufactured, and the above-mentioned demands of the customers could not be met.

JP-A-5-279740 JP 2002-206114 A JP-T-2004-508942 JP-T-2004-508944 JP-T-2004-509770 JP 2006-515801 A JP-A-9-194939 Japanese Patent Laid-Open No. 55-24942 JP 2006-124800 A

  The present invention utilizes a thin slab casting facility with a small capital investment, and uses a thin slab of appropriate thickness as a starting material, and finish hot rolling in an appropriate temperature range to produce an electromagnetic hot rolled steel strip. By this, non-oriented electromagnetic hot-rolled steel strip manufacturing technology is formed that has an excellent texture that is not obtained with conventional thin slab manufacturing equipment and has a high magnetic flux density in the 45 ° direction from the rolling direction. Is intended to provide.

The gist of the present invention is as follows.
(1) Mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
The remaining steel consisting of Fe and inevitable impurities is continuously cast into a thin cast piece having a plate thickness of 20 mm or more and 100 mm or less, followed by hot rolling, and a non-directional electromagnetic having a plate thickness of 0.4 mm or more and 2 mm or less. In the production method for obtaining a hot-rolled steel strip,
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.

650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃
(2) By mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
0.001% ≦ REM ≦ 0.01%
The remaining steel consisting of Fe and inevitable impurities is continuously cast into a thin cast piece having a plate thickness of 20 mm or more and 100 mm or less, followed by hot rolling, and a non-directional electromagnetic having a plate thickness of 0.4 mm or more and 2 mm or less. In the production method for obtaining a hot-rolled steel strip,
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.

650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃
(3) By mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
0.1% ≦ Cr ≦ 10%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
The remaining steel consisting of Fe and inevitable impurities is continuously cast into a thin cast piece having a plate thickness of 20 mm or more and 100 mm or less, followed by hot rolling, and a non-directional electromagnetic having a plate thickness of 0.4 mm or more and 2 mm or less. In the production method for obtaining a hot-rolled steel strip,
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.

650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃
(4) Mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
0.1% ≦ Cr ≦ 10%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
0.001% ≦ REM ≦ 0.01%
The remaining steel consisting of Fe and inevitable impurities is continuously cast into a thin cast piece having a plate thickness of 20 mm or more and 100 mm or less, followed by hot rolling, and a non-directional electromagnetic having a plate thickness of 0.4 mm or more and 2 mm or less. In the production method for obtaining a hot-rolled steel strip,
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.

650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃
(5) By mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
Furthermore, it contains at least one kind of Sn, Cu, and Sb in a range of 0.01% or more and 0.1% or less,
Non-directional electromagnetic hot-rolled steel strip having a thickness of 0.4 mm or more and 2 mm or less, continuously cast on molten steel consisting of Fe and inevitable impurities to a thin cast piece having a thickness of 20 mm or more and 100 mm or less, followed by hot rolling In the manufacturing method to obtain
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.

650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃
(6) By mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
0.001% ≦ REM ≦ 0.01%
Furthermore, it contains at least one kind of Sn, Cu, and Sb in a range of 0.01% or more and 0.1% or less,
Non-directional electromagnetic hot-rolled steel strip having a thickness of 0.4 mm or more and 2 mm or less, continuously cast on molten steel consisting of Fe and inevitable impurities to a thin cast piece having a thickness of 20 mm or more and 100 mm or less, followed by hot rolling In the manufacturing method to obtain
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.

650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃
(7) By mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
0.1% ≦ Cr ≦ 10%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
Furthermore, it contains at least one kind of Sn, Cu, and Sb in a range of 0.01% or more and 0.1% or less,
Non-directional electromagnetic hot-rolled steel strip having a thickness of 0.4 mm or more and 2 mm or less, continuously cast on molten steel consisting of Fe and inevitable impurities to a thin cast piece having a thickness of 20 mm or more and 100 mm or less, followed by hot rolling In the manufacturing method to obtain
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.

650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃
(8) By mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
0.1% ≦ Cr ≦ 10%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
0.001% ≦ REM ≦ 0.01%
Furthermore, it contains at least one kind of Sn, Cu, and Sb in a range of 0.01% or more and 0.1% or less,
Non-directional electromagnetic hot-rolled steel strip having a thickness of 0.4 mm or more and 2 mm or less, continuously cast on molten steel consisting of Fe and inevitable impurities to a thin cast piece having a thickness of 20 mm or more and 100 mm or less, followed by hot rolling In the manufacturing method to obtain
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.

650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃
(9) A non-directional electromagnetic hot-rolled steel strip obtained by any one of (1) to (8).
(10) An electromagnetic component manufactured by a non-directional electromagnetic hot-rolled steel strip manufactured by the method according to any one of (1) to (8), wherein the electromagnetic component is divided into an EI core and a rotating machine An electromagnetic component comprising one of a core, a transformer frame iron core, a small iron core, a reactor iron core, a rotating machine stator, a rotating machine rotor, a fluorescent light ballast, a spiral core, and a magnetic shield.

  According to the present invention, it is possible to manufacture a non-directional electromagnetic hot-rolled steel strip having a high magnetic flux density at a low cost.

  As a result of intensive studies on an inexpensive method for producing a non-directional electromagnetic hot-rolled steel strip that achieves a high magnetic flux density in a thin slab casting process capable of reducing the capital investment, the inventors have conducted a thin slab casting. By controlling the thickness to a constant condition, controlling the hot rolling rate from the thin cast slab to the electromagnetic hot rolled steel strip, and simultaneously rolling the thin cast slab at a low temperature of 850 ° C. or less, the electromagnetic heat It was newly found that the texture of the steel strip is appropriately controlled and the magnetic flux density in the direction of 45 degrees from the rolling direction is remarkably improved.

  As a result, it has become possible to provide a manufacturing method having excellent magnetic characteristics, omitting the cold rolling and recrystallization annealing steps and having a low manufacturing cost.

  This is a technical concept that is completely different from the technique of controlling the texture of the non-oriented electrical steel sheet by utilizing the columnar crystals of the cube orientation existing in the thin cast slab, as described above in Patent Document 1 and Patent Document 2. It is based on.

  As a result, in order to obtain a high magnetic flux density non-oriented electrical steel sheet in the prior art, the cost of hot-rolled sheet annealing, etc. to hot-rolled sheet obtained by a long facility consisting of blast furnace, steelmaking, rough hot rolling and finishing hot rolling It is possible to simplify the process in which such additional steps are performed, and then cold-rolled and finish-annealed.

  That is, the present invention provides a method for producing a low-cost, high magnetic flux density non-directional electromagnetic hot-rolled steel strip by means of a thin slab casting apparatus and hot rolling with a small capital investment. In particular, when performing this manufacturing method, the thin slab after casting is hot-rolled under appropriate conditions to finish it into an electromagnetic hot-rolled steel strip. It is disclosed that it is indispensable for the production of the belt.

First, the ingredients are explained.
In the present invention, excessive addition of Si reduces the magnetic flux density of the product, so its content is limited to 4.0% or less. On the other hand, an addition amount of 0.1% or more is required for the purpose of ensuring electric resistivity within a range not hindering improvement in magnetic flux density and reducing eddy current loss.

  Al is added in an amount of 0.01% or more for the purpose of securing the electric resistivity as in the case of Si or for deoxidation. If the addition amount exceeds 2.5%, the magnetic flux density is lowered, so the addition amount is set to 2.5% or less. Since it is possible to secure deoxidation and electrical resistivity with Si, Mn, etc., the addition of Al is not essential in the present invention.

  Therefore, there is no lower limit to the amount of Al added, and 2.5% ≦ Al. Since Al mixed as an inevitable impurity has high oxidation ability, the concentration becomes “tr.” Below the analytical measurement limit. This is often Al <0.001%.

  If C is contained excessively, magnetic aging occurs during use and iron loss increases, so the content is set to 0.004% or less.

  The present invention is aimed at producing a high magnetic flux density non-directional electromagnetic hot-rolled steel strip. Further, in order to reduce precipitates and improve iron loss, the C content is 0.003% or less. Is more preferable, and 0.002% or less is more preferable.

  S and N are partly re-dissolved during slab heating in the hot rolling process, and fine precipitates of MnS and AlN are reprecipitated during hot rolling to suppress grain growth during finish annealing. This causes the magnetic flux density and iron loss to deteriorate. For this reason, both the contents must be 0.003% or less.

  In addition, in the present invention, Mn may be added not only for deoxidation but also for the purpose of improving electrical resistivity, controlling recrystallization texture, or detoxifying precipitate MnS. If the Mn addition amount is less than 0.1%, the effect of Mn addition cannot be obtained, so the Mn addition amount is set to 0.1% or more. Further, if the Mn addition amount exceeds 2.0%, the magnetic flux density decreases, so the Mn addition amount is set to 2.0% or less.

  Further, Mn may be mixed in an amount of 0.1% or less as an inevitable impurity during the steelmaking process of the non-oriented electromagnetic hot rolled steel strip.

  In the present invention, P may be added for the purpose of increasing hardness and improving punchability. If the P addition amount is less than 0.03%, the effect is not sufficient, and if it exceeds 0.1%, the iron loss increases. Therefore, the P addition amount is set to 0.03% or more and 0.1% or less. P addition is particularly effective in non-directional electromagnetic hot-rolled steel strips with low Si content and low hardness. On the other hand, when the Si content is 1% or more, the addition of P is not always necessary because the hardness is sufficient.

  Moreover, although 0.025% or less of P is contained as an inevitable impurity, the content of the inevitable impurity level does not affect the magnetic properties of the non-oriented electromagnetic hot-rolled steel strip. Further, as described below, even if Cr is less than 0.1%, Sn, Cu and Sb are each less than 0.01% and REM is less than 0.001%, the magnetic properties of the present invention are not affected. Not acceptable.

  In the present invention, Cr may be added for the purpose of increasing the electrical resistivity. In this case, if the Cr addition amount is less than 0.1%, the addition effect cannot be obtained, and if the Cr addition amount exceeds 10%, the iron loss increases, so the Cr addition amount is 0.1% or more and 10%. % Or less. However, addition of less than 0.1% does not hinder the magnetic properties of the present invention and is included in the scope of the present invention.

  In addition, at least one of Sn, Cu, and Sb is added in the range of 0.01% or more and 0.1% or less for the purpose of improving the recrystallization texture of the product of the non-oriented electromagnetic hot-rolled steel strip. Also good. If the addition amount for this purpose is less than 0.01%, the effect of addition cannot be obtained, and if it exceeds 0.1%, the effect is saturated and the cost increases, so the addition amount is 0.01% or more and 0%. .1% or less. However, the addition of less than 0.01% does not inhibit the magnetic properties of the present invention and is included in the scope of the present invention.

  Further, in order to reduce harmful sulfide precipitation, Ca addition as shown in Patent Document 8 may be performed.

  Ti precipitates as fine TiN and increases iron loss. Further, when solute Ti is subjected to strain relief annealing on the non-oriented electromagnetic hot-rolled steel strip, solute Ti precipitates as TiC during the strain relief annealing and increases iron loss. Thus, Ti is an element harmful to the magnetism of the non-directional electromagnetic hot-rolled steel strip.

  If the Ti content exceeds 0.005%, a large amount of fine TiN precipitates in the steel, hindering the grain growth of the non-directional electromagnetic hot-rolled steel strip during finish annealing or strain relief annealing and increasing iron loss. Since it is not preferable, the Ti content is set to 0.005% or less.

  In the thin slab process, compared to the continuous casting process in which a slab with a thickness of about 200 mm is cast, the cooling rate at the time of solidification is fast and the precipitates are easily refined, so the Ti content should be reduced to 0.002% or less. Is preferred. In order to further improve the magnetic properties and achieve a high magnetic flux density, it is more preferable to reduce the Ti content to 0.001% or less.

  As an effective method of fixing iron in steel and reducing harmful sulfides while coarsely precipitating TiN and improving iron loss, REM is added to molten steel as disclosed in Patent Document 9. Also good.

  REM forms REM oxysulfide. In the present invention, this REM oxysulfide formation works particularly effectively for improving the magnetic properties of the non-directional electromagnetic hot-rolled steel strip.

  If the REM addition amount is less than 0.001%, the effect of addition is not sufficient, so the addition is determined to be 0.001% or more. Further, if it exceeds 0.01%, the iron loss increases, so the REM addition amount is set to 0.01% or less. However, addition of less than 0.001% does not hinder the magnetic properties of the present invention and is included in the scope of the present invention.

REM oxysulfide REM ₂ O ₂ S scavenges S and simultaneously precipitates TiN on REM ₂ O ₂ S, making the precipitate substantially coarse and simultaneously detoxifying Ti. Become. This has the effect of further promoting the reduction of iron loss.

O content for this purpose is preferably REM equivalent in _REM 2 _{O 2} S. REM may be added by a known method as disclosed in Patent Document 9.

  Here, REM means a rare earth element, and is a generic name of a total of 17 elements obtained by adding scandium and yttrium to 15 elements from lanthanum to lutetium called lanthanoids in the periodic table of elements.

  In the present invention, even if only one of them is used or two or more elements are used in combination, the effect is exhibited, and if it is within the range of the amount specified in the present invention, non-oriented electromagnetic hot rolled steel The effect is demonstrated in the belt.

  With thin slabs, it is difficult to secure a process of reheating for a long time in a slab heating furnace after casting, as in general continuous cast slabs. Therefore, detoxification of S and Ti is an important technical point for obtaining a non-directional electromagnetic hot-rolled steel strip having high magnetic flux density and low iron loss.

  Next, process conditions will be described.

  First, in this invention, the product obtained by the thin slab casting process and hot rolling is called an electromagnetic hot rolled steel strip, and it distinguishes from the hot rolled electrical steel plate obtained by the conventional hot rolling.

  Molten steel composed of the above components is cast into a thin cast slab of 20 mm to 100 mm. The casting method of the thin cast piece may be any known method such as a fixed mold method, a twin roll method, a single roll method, or a twin belt method. The fixing mold may be oscillated by a known method.

  The thin slab is hot-rolled to obtain an electromagnetic hot rolled steel strip having a predetermined thickness. At this time, in the present invention, the temperature at which hot rolling of a thin slab is started in order to obtain a non-directional electromagnetic hot rolled steel strip having a high magnetic flux density in the direction of 45 ° from the intended rolling direction by controlling the texture. Control is the most important point.

  After casting, when the thin slab is continuously subjected to hot rolling, the thin slab after casting is passed through a cooling zone and cooled by a known method such as water cooling, and then cooled to near the hot rolling start temperature. The temperature of the thin cast slab may be controlled to the hot rolling start temperature by a tunnel furnace, and the thin cast slab may be soaked at the same time and subjected to hot rolling. As long as a sufficient cooling zone for the thin slab can be secured, the thin slab may be cooled by air cooling. The temperature control of the thin cast slab by the tunnel furnace is performed by a known method such as induction heating or gas heating.

  In addition, after cooling the cast thin slab to the vicinity of the hot rolling start temperature in the cooling zone, it is wound in a coil shape to a predetermined length and simultaneously with heat retention or heating in a coil box by a known method. Soaking may be performed, the temperature of the thin cast slab may be controlled to the hot rolling start temperature, and then the thin cast slab may be rewound to be subjected to hot rolling. At this time, thin cast pieces that are hot-rolled back and forth may be joined by welding or the like by a known method, and hot rolling may be performed continuously.

  Moreover, in order to improve the windability of a thin slab, you may perform 2% or more and 50% or less pre-rolling before winding a thin slab into a coil shape. When the rolling ratio of the preliminary rolling is more than 50%, the equipment cost of the stand for reduction is increased, so 50% or less is preferable. If the rolling ratio of the preliminary rolling is less than 2%, the effect of improving the winding property of the thin cast slab cannot be obtained, so 2% or more is preferable.

  In addition to water cooling in the cooling zone, the thin cast piece may be cooled by contacting the cooling roll with the thin cast piece and transferring heat from the thin cast piece to the roll. At this time, the shape may be adjusted by applying a light pressure of 10% or less with a cooling roll. If the amount of reduction by the cooling roll is more than 10%, the rolling reaction force increases, and the equipment cost for increasing the rigidity of the cooling roll is increased, so the reduction amount is preferably 10% or less. A plurality of cooling rolls may be provided.

  The novel points of the technical idea of the present invention will be described below.

  Non-oriented electrical steel sheets are roughly classified into hot rolled electrical steel sheets and cold rolled electrical steel sheets. The former uses the hot-rolled hot-rolled steel strip as it is as a non-oriented electrical steel sheet. While the manufacturing process is simple, it is difficult to control the texture, and the characteristics are generally inferior to cold rolled electrical steel sheets.

  A cold-rolled electrical steel sheet is pickled and cold-rolled from a hot-rolled sheet obtained by finish hot-rolling, and then finish-annealed to give a surface film for use. In order to improve the properties, the cold rolling rate is appropriately controlled, or further, the hot rolled sheet is annealed to increase the crystal grain size before cold rolling, and then cold rolling and finishing. Annealed to give a surface coating and used.

  Although the characteristics are superior to those of hot-rolled electrical steel sheets, there is a problem that the manufacturing cost is higher than that of hot-rolled electrical steel sheets because it involves a cold-rolling, finish annealing process, and in some cases, a hot-rolled sheet annealing process before cold rolling.

  When the hot-rolled sheet is not annealed before cold rolling, the main orientation of the recrystallized structure obtained by cold rolling and finish annealing is a gamma fiber texture in which the <111> axis coincides with the normal direction of the plate surface. There is a problem that an optimum texture cannot be obtained for the non-oriented electrical steel sheet.

  On the other hand, when the hot rolled sheet is annealed before the cold rolling to increase the grain size before the cold rolling, a shear band is formed in the coarse crystal grain during the cold rolling. Crystal grains called Goss orientation recrystallize and grow during finish annealing. For this reason, the presence rate of the Goss orientation in the γ fiber is increased and the magnetic properties are improved.

  In the Goss direction, one of the <100> directions, which are the three easy axes of bcc iron, coincides with the rolling direction, and the remaining two are inclined at 45 ° above and below the plate surface. For this reason, it has the characteristic that the magnetic flux density of two directions of the rolling direction and the 180 degree opposite direction is excellent.

  A hot rolled electrical steel sheet is a non-oriented electrical steel sheet obtained by hot rolling, and since recrystallization proceeds immediately after hot rolling at high temperature, its texture is the same γ fiber as that of cold rolled electrical steel sheet. Yes, it is not a preferred texture for the original non-oriented electrical steel sheet.

  The inventors paid attention to this point and intensively studied a novel texture control method while applying a thin cast slab casting process having a low manufacturing cost to a conventional hot-rolled electrical steel sheet.

  As a result, by lowering the rolling start temperature of the thin slab, strain is released during hot rolling of the thin slab, and recrystallization of the texture of the electromagnetic hot-rolled steel strip is suppressed, which is referred to as a 45 ° cube texture. It was found that an electromagnetic hot rolled steel strip having a high magnetic flux density in the 45 ° direction from the rolling direction, which is a feature of the present invention, can be produced by maintaining the rolled texture.

  The 45 ° cube texture is a texture having an easy axis of magnetization in two directions inclined by 45 ° from the rolling direction in the plate surface and a high magnetic flux density in the four directions on the entire circumference. For this reason, there exists an advantage that the easy magnetization direction in a plate surface becomes twice the Goss direction which has a magnetization easy direction in two directions of the rolling direction and the 180 degree opposite direction.

  Also, in order to develop the rolling texture, it is important in the present invention to secure a certain amount or more of the reduction from the thin cast slab to the electromagnetic hot rolled steel strip so that a sufficient rolling rate can be obtained. I also found. The manufacturing method was designed based on these new technical ideas, and the manufacturing method of the low-cost, high magnetic flux density electromagnetic hot-rolled steel strip was completed.

  As described above, a rolling texture is developed in the electromagnetic hot-rolled steel strip of the present invention. This texture has four easy axes in the direction inclined by 45 ° from the rolling direction in the plate surface. On the other hand, in the Goss type high magnetic flux density cold rolled electrical steel sheet of the prior art, the easy magnetization direction can be obtained only in two directions of the rolling direction and the opposite direction in the plate surface.

  Thus, in the present invention, the direction of easy magnetization in the plate surface changed from two directions to four directions of the conventional high magnetic flux density electrical steel sheet, and increased twice. In addition, in the present invention, the scale of the casting apparatus and the hot rolling apparatus is smaller than before, and there is a cost advantage that the steps after the cold rolling are omitted.

  Patent Document 7 discloses a technique for rolling up a sheet bar after rough rolling, soaking it, and performing finish rolling as a method for producing a hot rolled electrical steel sheet. However, the purpose of this production method is to make the temperature of the hot-rolled steel sheet after finish rolling uniform from the front end to the rear end of the steel sheet and promote recrystallization. However, in this prior application, the recrystallized texture is a γ fiber in bcc iron, so the magnetic flux density is lowered. Therefore, this prior application is completely different in technical idea from the promotion of the development of the 45 ° cube texture by suppressing recrystallization in the present invention.

  In the present invention, if the thickness of the thin slab is less than 20 mm, the amount of reduction required for developing the texture of the electromagnetic hot-rolled steel strip intended by the present invention is insufficient, so the thickness of the thin slab is 20 mm. It is determined as above.

  If the thickness of the thin cast slab is less than 20 mm, there is less room for shape control of the electromagnetic hot-rolled steel strip by hot rolling, making it difficult to control the thickness and shape of the final product. Also from this viewpoint, the thickness of the thin slab is set to 20 mm or more.

  If the thickness of the thin cast slab exceeds 100 mm, the texture control effect of the electromagnetic hot-rolled steel strip is saturated and the reduction amount of the thin cast slab increases. Detract from the economics of the process. Therefore, also from this viewpoint, in the present invention, the thickness of the thin cast piece is set to 100 mm or less.

  If the thickness of the electromagnetic hot-rolled steel strip finished by hot rolling of a thin slab is more than 2 mm, a problem arises in handling properties such as rewinding at room temperature. Therefore, in the present invention, the thickness of the electromagnetic hot-rolled steel strip Is set to 2 mm or less.

  Moreover, if the thickness of the electromagnetic hot-rolled steel strip is less than 0.4 mm, it is difficult to control the thickness of the hot-rolled steel strip. Therefore, in the present invention, the thickness of the electromagnetic hot-rolled steel strip is set to 0.4 mm or more.

  When the hot rolling start temperature F0T exceeds 850 ° C., recrystallization proceeds during hot rolling, so the degree of accumulation of the 45 ° cube texture developed during rolling decreases, and the 45 ° direction from the rolling direction intended by the present invention. An electromagnetic hot rolled steel strip with a high magnetic flux density in the ° direction cannot be obtained. Therefore, in the present invention, the hot rolling start temperature F0T is set to 850 ° C. or less.

  Further, when the hot rolling start temperature F0T is less than 650 ° C., the rolling reaction force during hot rolling increases and rolling becomes difficult, so the hot rolling start temperature F0T is set to 650 ° C. or higher.

  When the hot rolling finish temperature FT is less than 550 ° C., the rolling reaction force increases and it becomes difficult to control the plate thickness, and the plate thickness system required for the non-oriented electromagnetic hot-rolled steel strip to be laminated is obtained. Therefore, the hot rolling end temperature is set to 550 ° C. or higher.

  When the hot rolling finish temperature exceeds 800 ° C, recrystallization proceeds during hot rolling, the degree of integration of 45 ° cube texture in the hot rolled steel strip decreases, and the magnetic flux density of the product significantly decreases. The end rolling temperature is set to 800 ° C. or lower.

  Thereby, the magnetic flux density of the electromagnetic hot-rolled steel strip obtained by hot rolling the thin slab obtained by the present invention is improved.

  Further, when the hot rolling start temperature and the hot rolling end temperature exceed the range of the present invention, the 45 ° cube texture of the electromagnetic hot rolled steel strip formed by hot rolling is caused by the progress of recrystallization and grain growth. The inventors have found that the magnetic flux density of the product disappears due to disappearance. Thus, the novelty of the present invention is developed while releasing the rolling distortion during hot rolling of the rolled texture of the electromagnetic hot rolled steel strip while suppressing recrystallization and grain growth in hot rolling of thin slabs. This is the most important technical idea of the present invention.

  Since the electromagnetic hot-rolled steel strip obtained by the present invention has a scale layer made of an oxide on the surface, a coating is usually unnecessary and may be used as it is. However, depending on the application, after pickling, a film may be applied and baked.

  The non-oriented electromagnetic hot-rolled steel strip obtained by the production method of the present invention may be used without being subjected to strain relief annealing after being punched into a predetermined shape, or may be used after being subjected to strain relief annealing. Good. Or after shaping into a core or the like having a predetermined shape through a punching step, the material may be used after being subjected to strain relief annealing.

The high magnetic flux density non-oriented electrical steel sheet obtained by the present invention includes electrical equipment, an EI core, an iron core of a rotating machine, a split core for a rotating machine, a stator for a rotating machine, a rotor for a rotating machine, Ideal for transformer frame iron cores, small iron cores, small transformers, reactor iron cores, fluorescent ballasts, spiral cores, magnetic shields, but also for various compressors, generators, and electric vehicles that require high output Suitable for iron core applications such as motors.
Next, examples of the present invention will be described.
[Example 1]
Molten steel having the components shown in Table 1 was cast to a thickness of 30 mm and a width of 1300 mm to form a thin slab for a non-directional electromagnetic hot rolled steel strip. The thin slab after casting is water-cooled in a cooling zone to a temperature of 770 ° C., then hot-rolled at a hot rolling start temperature of 770 ° C., and electromagnetic hot rolled steel having a thickness of 0.8 mm and 1.2 mm, respectively. Finished in a strip. At that time, the rolling schedule, the rolling speed and the cooling speed between the hot rolling stands were controlled to change the hot rolling end temperature.

  Further, as Comparative Example 2, an electromagnetic hot rolled steel strip having a thickness of 0.8 mm and a thickness of 1.2 mm was manufactured by setting the hot rolling start temperature of the same thin cast slab to 1000 ° C. and the hot rolling end temperature to 860 ° C. .

  Further, as Comparative Example 3, a slab having a thickness of 200 mm was obtained by continuous casting of steel having the same component, which was reheated to 1100 ° C. in a slab heating furnace, the plate thickness was set to 30 mm by rough hot rolling, and the finish hot rolling was heated. A hot rolled electrical steel sheet having a plate thickness of 0.8 mm and a thickness of 1.2 mm was manufactured at a hot rolling start temperature of 1000 ° C. and a hot rolling end temperature of 860 ° C.

  The Ar1 transformation point of this steel is 880 ° C.

  Thereafter, the Epstein specimen was cut in a direction that forms an angle of 45 ° to the left and right with respect to the rolling direction, and the magnetic properties were measured. At the time of Epstein measurement, the samples sheared to the left and right were prepared in half, and the samples sheared in the same direction were inserted into a pair of frames parallel to the Epstein frame.

  For the hot rolled electrical steel sheet of Comparative Example 3, Epstein samples were taken in the rolling direction and the sheet width direction, and the magnetic flux density was measured.

  Table 1 shows the components, and Table 2 shows the relationship between the hot rolling end temperature and the magnetic properties.

  From Table 2, by appropriately controlling the hot rolling end temperature within the range of 550 ° C. or higher and 800 ° C. or lower as defined in the present invention, costly processes such as hot-rolled sheet annealing can be omitted, and high magnetic flux density can be reduced. It is possible to produce a directional electromagnetic hot-rolled steel strip.

[Example 2]
Molten steel having the components shown in Table 3 was cast to a thickness of 30 mm and a width of 1250 mm to form a thin slab for a non-directional electromagnetic hot rolled steel strip. The thin slab after casting is cooled with water in a cooling zone to a temperature of 800 ° C., and this is heated in a tunnel furnace to adjust the temperature so that it is soaked within ± 5 ° C., and the hot rolling start temperature is set to 810 ° C. Hot rolling was performed to finish an electromagnetic hot rolled steel strip having a thickness of 0.4 mm and 1.5 mm. At that time, the rolling schedule, the rolling speed and the cooling speed between the hot rolling stands were controlled to change the hot rolling end temperature.

  Further, as Comparative Example 6, an electromagnetic hot rolled steel strip having a thickness of 0.4 mm and 1.5 mm was manufactured by setting the hot rolling start temperature of the same thin cast slab to 1000 ° C. and the hot rolling end temperature to 860 ° C. .

  Moreover, as Comparative Example 7, a slab having a thickness of 200 mm was formed by continuous casting of steel having the same component, and this was heated to 1100 ° C. in a slab heating furnace, the plate thickness was set to 30 mm by rough hot rolling, and the finish hot rolling was hot. A hot rolled electrical steel sheet having a sheet thickness of 0.4 mm and a thickness of 1.5 mm was manufactured at a rolling start temperature of 1000 ° C. and a hot rolling end temperature of 860 ° C.

  This steel is an α single phase steel having no αγ transformation up to the melting point.

  Thereafter, the Epstein specimen was cut in a direction that forms an angle of 45 ° to the left and right with respect to the rolling direction, and the magnetic properties were measured. At the time of Epstein measurement, the samples sheared to the left and right were prepared in half, and the samples sheared in the same direction were inserted into a pair of frames parallel to the Epstein frame.

  The hot rolled electrical steel sheet of Comparative Example 7 was subjected to magnetic measurement by taking an Upstein sample from the rolling direction and the sheet width direction.

  Table 3 shows the components, and Table 4 shows the relationship between the hot rolling end temperature and the magnetic properties.

  From Table 4, by appropriately controlling the hot rolling end temperature within the range of 550 ° C. or higher and 800 ° C. or lower as specified in the present invention, costly processes such as hot-rolled sheet annealing can be omitted, and high magnetic flux density can be reduced. It is possible to produce a directional electromagnetic hot-rolled steel strip.

[Example 3]
The molten steel of Steel 3 shown in Table 5 was cast to a thickness of 20 mm and a width of 1200 mm to form a thin cast piece of a non-directional electromagnetic hot rolled steel strip.

  The thin slab after casting is water-cooled in a cooling zone to lower the temperature once, and then heated in a tunnel furnace to adjust the temperature so that it is soaked within ± 5 ° C, and the hot rolling start temperature is changed. Hot rolling was performed to finish an electromagnetic hot rolled steel strip having a thickness of 1.0 mm and 2.0 mm. The rolling schedule, the rolling speed and the cooling speed between the hot rolling stands were controlled, and the hot rolling end temperature was 600 ° C.

  The Ar1 transformation point of this steel is 875 ° C.

  Al was below the detection limit because Al deoxidation and Al addition were not performed in the steelmaking stage. In the analytical instrument used in this experiment, the detection limit of Al is 0.001%, and Al determined to be below this limit amount is described as “tr.” In the table.

  Thereafter, the Epstein sample was cut in a direction that forms an angle of 45 ° to the left and right with respect to the rolling direction, and the magnetic properties were measured. At the time of Epstein measurement, the samples sheared to the left and right were prepared in half, and the samples sheared in the same direction were inserted into a pair of frames parallel to the Epstein frame.

  Table 5 shows the components, and Table 6 shows the relationship between the hot rolling start temperature and the magnetic properties.

  From Table 6, by appropriately controlling the finishing hot rolling start temperature to 650 ° C. or higher and 850 ° C. or lower as defined in the present invention, costly processes such as hot-rolled sheet annealing can be omitted, and high magnetic flux density can be reduced. It is possible to produce a directional electromagnetic hot-rolled steel strip.

[Example 4]
The molten steel of Steel 4 shown in Table 7 was cast to a thickness of 20 mm and a width of 1100 mm to obtain a thin cast piece for a non-directional electromagnetic hot rolled steel strip.

  The thin slab after casting is cooled with water in a cooling zone to a temperature of 630 ° C., and this is heated in a tunnel furnace to adjust the temperature so that it is soaked within ± 5 ° C., and the hot rolling start temperature is changed. Hot rolling was performed to finish an electromagnetic hot rolled steel strip having a thickness of 0.65 mm. The rolling reduction temperature, the rolling speed and the cooling speed between the hot rolling stands were controlled, and the hot rolling end temperature was set to 605 ° C.

  Thereafter, the Epstein sample was cut in a direction that forms an angle of 45 ° to the left and right with respect to the rolling direction, and the magnetic properties were measured. At the time of Epstein measurement, the samples sheared to the left and right were prepared in half, and the samples sheared in the same direction were inserted into a pair of frames parallel to the Epstein frame.

  This steel is an α single phase having no αγ transformation up to the melting point.

  Table 7 shows the components, and Table 8 shows the relationship between the hot rolling start temperature and the magnetic properties.

  From Table 8, it is possible to produce a non-directional electromagnetic hot-rolled steel strip having a high magnetic flux density by appropriately controlling the finishing hot rolling start temperature to 650 ° C. or higher and 850 ° C. or lower as defined in the present invention. .

[Example 5]
Molten steel having the components shown in Table 9 was cast to a thickness of 30 mm and a width of 1200 mm to form a thin slab for a non-directional electromagnetic hot rolled steel strip. The thin slab after casting is water-cooled in a cooling zone to a temperature of 775 ° C., and this is heated in a tunnel furnace to adjust the temperature so that it is within ± 5 ° C., and the hot rolling start temperature is 780 ° C. Then, the rolling schedule, the rolling speed, and the cooling speed between the hot rolling stands were controlled, and the hot rolling finish temperature was set to 670 ° C. to finish an electromagnetic hot rolled steel strip having a thickness of 0.50 mm.

  Thereafter, the Epstein sample was cut in a direction that forms an angle of 45 ° to the left and right with respect to the rolling direction, and the magnetic properties were measured. At the time of Epstein measurement, the samples sheared to the left and right were prepared in half, and the samples sheared in the same direction were inserted into a pair of frames parallel to the Epstein frame.

  In this experiment, sol-Al having a detection limit of 0.001% or less was described as “tr.” In the table.

  Table 9 shows the components of the present invention and comparative examples, and Table 10 shows the measurement results of the relationship between the finish annealing temperature and the magnetic properties.

  From Table 10, it is possible to produce a non-directional electromagnetic hot-rolled steel strip having a high magnetic flux density by adjusting the Si and Al contents within the component ranges of the present invention.

  In Comparative Example 13 using steel 5, the Si content is lower than the range of the present invention, and the magnetic flux density value is remarkably low and the iron loss is lower than that of Inventive Example 23 in which the alloy content is almost equal. Highly unsuitable.

  In Comparative Example 14 using steel 18, the Si content exceeds the range of the present invention, and the magnetic flux density is extremely low even when considering the alloy composition and content in comparison with Example 32 of the present invention. Unsuitable.

  In Comparative Example 15 using steel 19, the Al content exceeds the range of the present invention, and the magnetic flux density is extremely low even when considering the alloy composition and content in comparison with Example 32 of the present invention. Unsuitable.

  As described above, a high magnetic flux density non-directional electromagnetic hot-rolled steel strip can be manufactured by controlling the alloy composition of Si, Al, etc. within the range defined by the present invention and manufacturing the alloy under appropriate process conditions.

  In Steel 11, Mn of 0.1% or less, P and tr. Al is mixed as an inevitable impurity. However, within this range, the magnetic properties of the non-directional electromagnetic hot-rolled steel strip are not deteriorated.

[Example 6]
The molten steel having the components shown in Table 11 was used as a thin cast piece for non-oriented electrical steel having a thickness of 1100 mm in each thickness.

  The thin slab after casting is cooled with water in a cooling zone to a temperature of 770 ° C, and this is heated in a tunnel furnace to adjust the temperature so that it is soaked within ± 5 ° C, and the hot rolling start temperature is set to 775 ° C. The hot rolling end temperature was set to 665 ° C. by controlling the rolling speed and the cooling speed between the hot rolling stands, and the electromagnetic hot rolled steel strip having a thickness of 0.70 mm was finished.

  Further, in the present invention example 38, the present invention example 40, the present invention example 42, the present invention example 49, the present invention example 51, and the present invention example 53, the thin slab after casting was cooled with water in a cooling zone, and the temperature was 770 ° C. After winding this into a coil, it was placed in a coil box furnace, heated for 16 minutes, soaked within ± 5 ° C., unwound again and returned to the sheet bar shape, and then the hot rolling start temperature Was set to 775 ° C., the hot rolling finish temperature was set to 665 ° C., and an electromagnetic hot rolled steel strip having a thickness of 0.70 mm was finished.

  Thereafter, the Epstein sample was cut in a direction that forms an angle of 45 ° to the left and right with respect to the rolling direction, and the magnetic properties were measured. At the time of Epstein measurement, the samples sheared to the left and right were prepared in half, and the samples sheared in the same direction were inserted into a pair of frames parallel to the Epstein frame.

  Table 11 shows the components of the present invention and the comparative example, and Table 12 shows the relationship between the thickness of the thin cast slab and the magnetic properties.

  From Table 12, it can be seen that the magnetic flux density of the non-directional electromagnetic hot-rolled steel strip is improved by setting the plate thickness of the thin cast piece to 20 mm or more and 100 mm or less.

[Example 7]
The molten steel having the components shown in Table 13 was made into a thin cast piece for a non-directional electromagnetic hot rolled steel strip having a thickness of 30 mm and a width of 1100 mm.

  The thin slab after casting was water-cooled in a cooling zone, and hot rolling was started at 760 ° C. The rolling schedule, the rolling speed and the cooling speed between the hot rolling stands were controlled, and the end temperature of hot rolling was set to 650 ° C. to finish an electromagnetic hot rolled steel strip having a thickness of 0.5 mm.

  Thereafter, the Epstein sample was cut in a direction that forms an angle of 45 ° to the left and right with respect to the rolling direction, and the magnetic properties were measured. At the time of Epstein measurement, the samples sheared to the left and right were prepared in half, and the samples sheared in the same direction were inserted into a pair of frames parallel to the Epstein frame.

  Table 11 shows the components and magnetic measurement results of the inventive examples and comparative examples.

  In the examples of the present invention using the steel 22 and the steel 26, the amount of REM added is less than the range defined in the present invention, and the magnetic characteristics are not improved by the REM addition effect, but the magnetic characteristics level of the present invention is satisfied.

  In the comparative example using steel 24 and steel 29, the amount of REM added exceeds the range defined in the present invention, the iron loss is increased, the magnetic flux density is low, and the magnetic properties are inferior to those of the present invention example.

  In contrast, in Steel 23, Steel 25, Steel 27, Steel 28, and Steel 30, the amount of REM added is within the range defined by the present invention, and the magnetic flux density is high, the iron loss is low, and the magnetic properties are excellent.

  Steel 31 and steel 44 have a Ti content exceeding the range defined in the present invention, so that the magnetic flux is higher than steel 40, steel 41, steel 42 and steel 43 whose Ti content is within the range defined in the present invention. The density is low and the iron loss is excessive.

  Since the amount of Sn added to the steel 32 is less than the range defined in the present invention, the magnetic characteristics are not improved due to the effect of Sn addition, but the magnetic characteristics level of the present invention is satisfied.

  Since the amount of Sn added to the steel 34 exceeds the range defined in the present invention, the magnetic flux density is lower than that of the steel 33 in which the amount of Sn added is within the range defined in the present invention.

  Since the steel 35 has a Cr addition amount less than the range defined in the present invention, iron loss is not improved by the Cr addition effect, but the magnetic property level of the present invention is satisfied.

  Since the amount of Cr added in the steel 39 exceeds the range defined in the present invention, the iron loss is increased compared to the steel 36, steel 37, and steel 38 in which the Cr added amount is in the range defined in the present invention.

  In Steel 23, Steel 27, and Steel 40, 0.2% or less of Mn, 0.025% or less of P, tr. Al is mixed as an inevitable impurity. However, within these ranges, these do not affect the magnetic properties of the non-oriented electromagnetic hot-rolled steel strip.

  In Steel 28 and Steel 41, 0.2% or less of Mn and 0.025% or less of P are mixed as inevitable impurities. However, within these ranges, these do not affect the magnetic properties of the non-oriented electromagnetic hot-rolled steel strip.

  Since the amount of Sb added to steel 45 is less than the range defined in the present invention, the magnetic flux density is not improved by the effect of Sb addition, but the magnetic property level of the present invention is satisfied.

  Since the Sb addition amount of the steel 47 exceeds the range defined in the present invention, the magnetic flux density is lower than that of the steel 46 whose Sb addition amount is in the range defined by the present invention.

  Since the steel 48 has a Cu addition amount less than the range defined in the present invention, the magnetic flux density is not improved by the Cu addition effect, but the magnetic property level of the present invention is satisfied.

  Steel 50 has a lower magnetic flux density than steel 49 whose Cu addition amount is in the range defined in the present invention because the Cu addition amount exceeds the range defined in the present invention.

  As described above, it can be seen that excellent magnetic properties having a high magnetic flux density and a low iron loss can be obtained by controlling the addition amount within the range defined in the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to manufacture the non-directional electromagnetic hot-rolled steel strip with a high magnetic flux density at low cost, and industrial applicability is high.

Claims (10)

In mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
The remaining steel consisting of Fe and inevitable impurities is continuously cast into a thin cast piece having a plate thickness of 20 mm or more and 100 mm or less, followed by hot rolling, and a non-directional electromagnetic having a plate thickness of 0.4 mm or more and 2 mm or less. In the production method for obtaining a hot-rolled steel strip,
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.
650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃ In mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
0.001% ≦ REM ≦ 0.01%
The remaining steel consisting of Fe and inevitable impurities is continuously cast into a thin cast piece having a plate thickness of 20 mm or more and 100 mm or less, followed by hot rolling, and a non-directional electromagnetic having a plate thickness of 0.4 mm or more and 2 mm or less. In the production method for obtaining a hot-rolled steel strip,
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.
650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃ In mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
0.1% ≦ Cr ≦ 10%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
The remaining steel consisting of Fe and inevitable impurities is continuously cast into a thin cast piece having a plate thickness of 20 mm or more and 100 mm or less, followed by hot rolling, and a non-directional electromagnetic having a plate thickness of 0.4 mm or more and 2 mm or less. In the production method for obtaining a hot-rolled steel strip,
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.
650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃ In mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
0.1% ≦ Cr ≦ 10%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
0.001% ≦ REM ≦ 0.01%
The remaining steel consisting of Fe and inevitable impurities is continuously cast into a thin cast piece having a plate thickness of 20 mm or more and 100 mm or less, followed by hot rolling, and a non-directional electromagnetic having a plate thickness of 0.4 mm or more and 2 mm or less. In the production method for obtaining a hot-rolled steel strip,
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.
650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃ In mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
Furthermore, it contains at least one kind of Sn, Cu, and Sb in a range of 0.01% or more and 0.1% or less,
Non-directional electromagnetic hot-rolled steel strip having a thickness of 0.4 mm or more and 2 mm or less, continuously cast on molten steel consisting of Fe and inevitable impurities to a thin cast piece having a thickness of 20 mm or more and 100 mm or less, followed by hot rolling In the manufacturing method to obtain
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.
650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃ In mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
0.001% ≦ REM ≦ 0.01%
Furthermore, it contains at least one kind of Sn, Cu, and Sb in a range of 0.01% or more and 0.1% or less,
Non-directional electromagnetic hot-rolled steel strip having a thickness of 0.4 mm or more and 2 mm or less, continuously cast on molten steel consisting of Fe and inevitable impurities to a thin cast piece having a thickness of 20 mm or more and 100 mm or less, followed by hot rolling In the manufacturing method to obtain
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.
650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃ In mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
0.1% ≦ Cr ≦ 10%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
Furthermore, it contains at least one kind of Sn, Cu, and Sb in a range of 0.01% or more and 0.1% or less,
Non-directional electromagnetic hot-rolled steel strip having a thickness of 0.4 mm or more and 2 mm or less, continuously cast on molten steel consisting of Fe and inevitable impurities to a thin cast piece having a thickness of 20 mm or more and 100 mm or less, followed by hot rolling In the manufacturing method to obtain
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.
650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃ In mass% in steel
0.1% ≦ Si ≦ 4.0%
0.1% ≦ Mn ≦ 2.0%
0.03% ≦ P ≦ 0.1%
Al ≦ 2.5%
0.1% ≦ Cr ≦ 10%
C ≦ 0.004%
S ≦ 0.003%
N ≦ 0.003%
Ti ≦ 0.005%
0.001% ≦ REM ≦ 0.01%
Furthermore, it contains at least one kind of Sn, Cu, and Sb in a range of 0.01% or more and 0.1% or less,
Non-directional electromagnetic hot-rolled steel strip having a thickness of 0.4 mm or more and 2 mm or less, continuously cast on molten steel consisting of Fe and inevitable impurities to a thin cast piece having a thickness of 20 mm or more and 100 mm or less, followed by hot rolling In the manufacturing method to obtain
A method for producing a non-oriented electromagnetic hot-rolled steel strip, characterized in that a hot rolling start temperature F0T and a hot rolling end temperature FT of a thin cast slab after continuous casting are respectively determined as follows.
650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃   A non-directional electromagnetic hot-rolled steel strip obtained by the method according to any one of claims 1 to 8.   An electromagnetic component manufactured by a non-directional electromagnetic hot-rolled steel strip manufactured by the method according to any one of claims 1 to 8, wherein the electromagnetic component is an EI core, a split core for a rotating machine, or a frame iron core for a transformer. An electromagnetic component comprising any one of a small iron core, a core for a reactor, a stator for a rotating machine, a rotor for a rotating machine, a ballast for a fluorescent lamp, a spiral core, and a magnetic shield.