JP2011111658A - Method for producing non-oriented magnetic steel sheet having high magnetic flux density - Google Patents

Abstract

A non-oriented electrical steel sheet manufacturing method capable of obtaining a high magnetic flux density at low cost is provided.
Nondirectional electromagnetic waves satisfying 0.1% ≦ Si ≦ 2.0%, Al ≦ 1.0% and 0.1% ≦ Si + 2Al ≦ 2.0%, and containing C ≦ 0.004% In the production of steel sheets, the hot rolling slab heating temperature ST is 700 ° C. ≦ ST ≦ 1150 ° C., the finish rolling start temperature F 0 T is 650 ° C. ≦ F 0 T ≦ 850 ° C., and the finish hot rolling end temperature FT is 550 ° C. ≦ FT ≦ 800 ° C. Stipulated in
[Selection] Figure 3

Description

  The present invention relates to a method for producing a non-oriented electrical steel sheet having a high magnetic flux density, which is used as an iron core material for electrical equipment.

In recent years, in the fields of electrical machinery, especially rotating machines where non-oriented electrical steel sheets are used as iron core materials, and in the fields of medium and small transformers, global power conservation, energy conservation, and global environmental conservation such as CFC regulations Among these trends, the trend toward higher efficiency is spreading rapidly.
For this reason, there is an increasing demand for non-oriented electrical steel sheets to improve their characteristics, that is, to achieve high magnetic flux density and low iron loss.

  The reduction of iron loss in non-oriented electrical steel sheets has been achieved mainly by reducing the Joule heat loss due to eddy current loss flowing in each steel sheet forming the iron core during use by increasing the electrical resistivity by adding Si and Al. It was.

  On the other hand, as an energy loss of the entire machine including the rotating machine and the iron core, the contribution of copper loss, which is a Joule heat loss caused by current flowing through the coil theory wound around the iron core, is also important. In order to reduce the copper loss, it is effective to reduce the current density required for excitation with the same magnetic field strength, and development of a material that exhibits a higher magnetic flux density with the same excitation current is indispensable.

That is, development of a high magnetic flux density non-oriented electrical steel sheet is essential. The use of high magnetic flux density non-oriented electrical steel sheets increases the magnetic flux density that is excited, making it possible to reduce the size and weight of the iron core of electrical equipment such as rotating machines and small transformers. In a moving body such as an automobile or a train, the energy loss during operation can be reduced by reducing the weight of the entire system.
Further, in the rotating machine, the torque is increased, and a smaller and higher output rotating machine can be realized.

  Thus, the realization of a high magnetic flux density non-oriented electrical steel sheet not only can reduce the energy loss during the operation of the iron core and the rotating machine, but also has a ripple effect on the entire system including it. There is nothing.

  Conventionally, in non-oriented electrical steel sheets that have been developed for the purpose of low iron loss, elements having high electrical resistivity such as Si and Al have been mainly added, but if the content of these elements increases, non-oriented Since the saturation magnetic flux density of the heat-resistant electrical steel sheet is reduced, the excitation current has to be increased in order to increase the operating magnetic flux density when actually used as an electrical device, resulting in an increase in copper loss. Therefore, the non-oriented electrical steel sheet containing many elements having high electrical resistivity such as Si and Al has to reduce the operating magnetic flux density. As a result, for example, it is difficult to exert high torque in a rotating machine. There was a problem.

Then, the non-oriented electrical steel sheet which restricted content of Si and Al has been proposed.
Patent Document 1 discloses that C ≦ 0.02%, the total amount of Si or Si and Al is 1.5% or less, Mn: 1.0% or less, and P: 0.20% or less, with the balance being inevitable impurities. The finish rolling finish temperature is a low temperature finish of 600 to 700 ° C., wound at a temperature of 500 ° C. or less, and this steel strip is annealed for 30 seconds or more and 15 minutes or less in a temperature range below the A3 transformation point. A method for producing a conductive electrical steel sheet is disclosed.

However, in this manufacturing method, a step of subjecting the hot-rolled steel strip after hot-rolling to hot-rolled sheet annealing is indispensable. Therefore, there is a problem that causes an increase in cost, and a non-oriented electrical steel sheet with a strong demand for cost reduction. This technology was unacceptable to consumers.
Further, in the examples, the C content is 0.004% or more in mass%, and as described later, the non-directional electromagnetic of the single cold rolling method omitting the hot-rolled sheet annealing found in the present invention. In the steel plate manufacturing method, by limiting the C content to a certain value or less, there is no technical idea that the effect of improving the magnetic flux density of the product is enhanced through texture control by controlling an integrated process starting from hot rolling.

In Patent Document 2, a steel having a total amount of Si and Al of 1.5% or less is used, and in the finish hot rolling, the hot rolling end temperature is finished at 600 ° C. or more and 700 ° C. or less, and the reduction ratio is 75% or more. A manufacturing method in which finish annealing is performed after cold rolling at 85% or less is disclosed.
However, according to the study by the present inventors, the magnetic properties of the product are unstable only by specifying the finish hot rolling end temperature, and it is important to control the rolling start temperature to obtain stable magnetic properties. I found out. In addition, the C concentrations of 0.006% and 0.005% shown in the examples of the publication have a problem that the effect of hot rolling at low temperature is insufficient and the improvement of the magnetic flux density is insufficient.

Furthermore, as a method of improving the magnetic properties of the non-oriented electrical steel sheet by improving the primary recrystallization texture, Sn addition as in Patent Document 3, Sn and Cu addition as in Patent Document 4, or Patent Document 5 For example, a method for producing a non-oriented electrical steel sheet having excellent magnetic properties by improving the texture by adding Sb is disclosed.
However, even with the addition of these texture control elements, such as Sn, Cu, or Sb, it is sufficient to meet the demand for low-cost supply of high magnetic flux density, low iron loss non-oriented electrical steel sheets of today's customers. I could not do it.

  In addition, although measures have been taken on the manufacturing process such as the finishing annealing cycle as described in Patent Document 6, the magnetic flux density is sufficient even if the iron loss is reduced. There was no improvement.

  Thus, in the prior art, it has not been possible to manufacture a high magnetic flux density non-oriented electrical steel sheet that is advantageous for downsizing of iron cores, which is strongly demanded by recent customers. I couldn't respond.

JP 58-204126 A JP 59-104429 A JP-A-55-158252 JP 62-180014 A Japanese Patent Laid-Open No. 59-100197 JP-A-57-35265

  An object of the present invention is to solve such problems in the prior art and to provide a high magnetic flux density non-oriented electrical steel sheet.

  The present invention performs a finish hot rolling process under specific conditions to create a hot-rolled sheet texture in advance, so that even if hot-rolled sheet annealing is omitted, it is cold-rolled and finish-annealed. In addition to newly discovering that it is possible to control the recrystallized texture after the processing, the carbon content contained in the steel under the above specific conditions is further reduced when performing this production method. This is a result of a new finding that the effect of the finish hot rolling process is significantly affected. This provides a technique for producing a non-oriented electrical steel sheet having a high magnetic flux density by a method that is cheaper than the prior art.

The gist of the present invention is as follows.
The invention of claim 1
In steel, 0.1% ≦ Si ≦ 2.0,% Al ≦ 1.0% by mass%,
And 0.1% ≦ Si + 2Al ≦ 2.0% is satisfied,
Further, the steel containing C ≦ 0.004%, S ≦ 0.003%, N ≦ 0.003%, the balance being Fe and inevitable impurities is used as a slab for rough rolling and subsequent finishing heat in hot rolling. In the method for producing a non-oriented electrical steel sheet, the hot rolled sheet is subjected to rolling, pickled, subjected to a single cold rolling step, and then subjected to finish annealing.
Finishing hot rolling slab heating temperature ST, finishing hot rolling start temperature F0T, finishing hot rolling end temperature FT, respectively,
700 ℃ ≦ ST ≦ 1150 ℃
650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃
A method for producing a non-oriented electrical steel sheet having a high magnetic flux density, characterized by being defined as follows:

Further, the invention of claim 2 relating to the electrical steel sheet manufactured by the invention of claim 1
In the (100) pole figure created by X-ray diffraction measurement in 1 / 10th layer in the plate thickness direction from the surface of the steel plate,
α = 80 ° and β are respectively β = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, 330 °, and the strengths are all 1.0 or more,
And in the (100) pole figure measured by X-ray diffraction measurement in the half layer thickness direction center layer of the steel plate,
There is a region where the intensity is 1.0 or more in the regions of α and β where 50 ° ≦ α ≦ 70 ° and β is determined by β = 0 °, 60 °, 120 °, 180 °, 240 °, and 300 °, respectively. A non-oriented electrical steel sheet, characterized by
Similarly, the invention of claim 3
In the (100) pole figure created by X-ray diffraction measurement in 1 / 10th layer in the plate thickness direction from the surface of the steel plate,
α = 80 ° and β are β = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, 330 °, all of strengths of 1.0 or more, and on the same pole figure, α = 90 ° and β are respectively β = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, 330 °, and the strengths are all 1.0 or more,
And in the (100) pole figure created by X-ray diffraction measurement in the half layer which is the center layer in the plate thickness direction of the steel plate,
There is a region where the intensity is 1.0 or more in the regions of α and β where 50 ° ≦ α ≦ 70 ° and β is determined by β = 0 °, 60 °, 120 °, 180 °, 240 °, and 300 °, respectively. A non-oriented electrical steel sheet, characterized by
Furthermore, the invention of claim 4
The strengths of the (100), (411), and (111) planes in the reverse pole figure obtained by X-ray diffraction measurement at a 1 / 10th layer in the thickness direction from the surface of the steel sheet are I (100) and I ( 411), I (111)
I (100) ≧ 2.0
I (411) ≧ 1.5
I (111) ≦ 4.0
And,
{I (100) + I (411)} / I (111) ≧ 1.0
It is a non-oriented electrical steel sheet characterized by satisfying.

Furthermore, the invention of claim 5
In order to improve the magnetic properties of this non-oriented electrical steel sheet, a non-oriented electrical steel sheet manufacturing method is characterized in that the rolling rate in the cold rolling step is 85% or more and 95% or less.

Furthermore, invention of Claim 6 processes the electromagnetic steel plate manufactured by the manufacturing method of the non-oriented electrical steel plate of Claim 1 or 5, or the electromagnetic steel plate of any one of Claims 2-4 into an iron core. This is a shearing method for a non-oriented electrical steel sheet in which the direction in which the magnetic flux flows in the iron core coincides with a direction inclined 45 degrees to the left and right within the steel sheet surface from the rolling direction of the steel sheet.
Furthermore, the invention of claim 7 is an electromagnetic component manufactured by the non-oriented electrical steel sheet manufactured by the method of claim 6, wherein the electromagnetic component includes an EI core, a split core for a rotating machine, a frame iron core for a transformer, An electromagnetic component characterized by being a small iron core, a reactor core, or a spiral core.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to manufacture the non-oriented electrical steel plate with a high magnetic flux density, and the electromagnetic components using the electromagnetic steel plate at low cost.

In the (100) pole figure of one-tenth layer from the surface layer in the plate thickness direction of the steel sheet, it is a diagram showing the position where the strength is defined, ●: α = 90 ° and β is β = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, 330 °, ◆: α = 80 ° and β is β = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, Each point is 330 °. In the (100) pole figure of the half-thickness center layer of the steel sheet, 50 ° ≦ α ≦ 70 ° and β is β = 0 °, 60 °, 120 °, 180 °, 240 °, 300 °, respectively. 6 shows a range (both end arrows) where the strength is defined by a certain present invention. It is a (100) pole figure in 1 / 10th sheet thickness from a surface layer. It is a (100) pole figure in a half layer thickness from a surface layer. It is a figure which shows the punching method of EI core of this invention example and a comparative example. It is a figure which shows the punching method of the frame core of this invention example and a comparative example. It is a figure which shows the punching method of the split core of the example of this invention and a comparative example. It is a figure which shows the punching method of the spiral core of the example of this invention and a comparative example.

  As a result of intensive studies on an inexpensive method for producing a non-oriented electrical steel sheet that achieves an unprecedented high magnetic flux density, the inventors have conducted a finish hot rolling process under specific conditions to collect a set of hot rolled sheets. By creating the structure in advance, it is newly discovered that it is possible to control the recrystallization texture after cold rolling and finish annealing even if hot-rolled sheet annealing is omitted. Furthermore, it has been newly found out that the content of carbon contained in steel has a significant effect on the effect of the finish hot rolling process under the specific conditions when performing this production method. And based on these knowledge, the manufacturing technique of the non-oriented electrical steel sheet which is high magnetic flux density by the method cheaper than a prior art is provided.

Hereinafter, the present invention will be sequentially described.
First, the components of steel will be described.

  In the present invention, excessive addition of Si is harmful because it reduces the magnetic flux density of the product, so its content is limited to 2.0% 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 may be added for the purpose of securing electrical resistivity in the same manner as Si. In the present invention, since the addition of Al is not essential, the lower limit of the content is not determined. On the other hand, like Si, excessive addition reduces the magnetic flux density of the product and is harmful, so its content is limited to 1.0% or less.

  Since Si and Al are added to ensure electrical resistivity, the total amount of (Si + 2Al) needs to be 0.1% or more. On the other hand, if the total amount of (Si + 2Al) exceeds 2.0%, the magnetic flux density of the product is reduced, which is harmful. Therefore, the total amount of (Si + 2Al) is limited to 2.0% or less.

The content of C is controlled to a certain amount or less. As will be described later, this is an important new finding in order to sufficiently exhibit the effect of texture control in an integrated process from finish hot rolling to finish annealing.
If it is only a viewpoint which prevents the increase in the loss by the magnetic aging in use as a non-oriented electrical steel sheet like the past, it is enough if the content is 0.004% or less.
However, in the present invention, if the C content is more than 0.004%, the recrystallization texture of the product after finish annealing cannot be controlled successfully, and a high magnetic flux density cannot be obtained. Therefore, the C content is set to 0.004% or less. Furthermore, in order to enhance the effect of improving the magnetic flux density of the non-oriented electrical steel sheet in the present invention, the C content is preferably 0.003% or less, and more preferably 0.002% or less.

In the present invention, a high magnetic flux density can be achieved by reducing S and N.
S and N are partly re-dissolved during slab heating in the hot rolling process, and fine precipitates of MnS and AlN are re-precipitated during hot rolling to suppress crystal grain growth during finish annealing, and magnetic flux It causes the density and iron loss to deteriorate. For this reason, both the contents must be 0.003% or less.

Next, process conditions will be described.
The steel slab composed of the above components is melted in a converter and manufactured by continuous casting or ingot-bundling rolling. The steel slab is heated by a known method. The slab is hot rolled to a predetermined thickness.

  In hot rolling, if the slab heating temperature ST is less than 700 ° C., the magnetic flux density of the product decreases, so the slab heating temperature is set to 700 ° C. or higher. On the other hand, when the slab heating temperature exceeds 1150 ° C., impurities such as S in the steel re-dissolve and reprecipitates finely during finish hot rolling, preventing crystal grain growth during finish annealing, resulting in significant iron loss. The slab heating temperature is set to 1150 ° C. or lower because it deteriorates and hinders recrystallization control during finish annealing and lowers the magnetic flux density.

  The finish hot rolling start temperature F0T is set to 650 ° C. or higher because when the temperature is less than 650 ° C., the rolling reaction force during finish hot rolling increases and rolling becomes difficult. On the other hand, when the finish hot rolling start temperature exceeds 850 ° C., the recrystallization progress rate during finish hot rolling becomes too high, and the effect of the present invention for controlling the texture of the hot rolled steel strip while performing finish hot rolling is effective. It is damaged, and as a result, the magnetic flux density of the product is remarkably lowered.

  If the finish hot rolling end temperature FT is less than 550 ° C., the thickness control becomes difficult and the magnetic flux density of the product decreases, so the finish hot rolling end temperature is set to 550 ° C. or more. When the finish hot rolling finish temperature exceeds 800 ° C., the recrystallization progress rate during finish hot rolling becomes too high, and the effect of the present invention for controlling the texture of the hot rolled steel strip while performing finish hot rolling is impaired. As a result, the magnetic flux density of the product is remarkably lowered, so the finish hot rolling end temperature is set to 800 ° C. or less.

  In the present invention, since it is necessary to control the texture of the hot-rolled steel strip during finish hot rolling, it is necessary to control the slab heating temperature, the finish hot rolling start temperature, and the finish hot rolling end temperature. Thereby, the texture of the hot-rolled steel strip is preliminarily formed before cold rolling, and the effect of increasing the magnetic flux density by controlling the recrystallization texture during the subsequent cold rolling and finish annealing.

This effect is promoted by controlling the C content as described in the explanation of the components.
The reason why low iron loss can be achieved by this technical idea is under intensive study at present. However, it is possible to improve the texture of hot-rolled steel strip by carrying out finish hot rolling in a low temperature range. Therefore, among the crystal grains in the recrystallized texture of the product after cold rolling and recrystallization, the grains near the orientation with the {100} plane parallel to the plate surface can be enriched near the surface layer of the steel plate This is presumed to be the mechanism for improving the magnetic flux density of the present invention.

  Furthermore, if the hot rolling start temperature and hot rolling end temperature are too high, the texture of the hot rolled steel strip formed by finishing hot rolling in the α phase region disappears due to the progress of recrystallization and grain growth, and the magnetic flux density of the product is reduced. The inventors have found that it decreases.

  Moreover, the hot-rolled sheet annealing that has been used in the prior art to improve the magnetic flux density of the non-oriented electrical steel sheet is the hot-rolled sheet in the texture in the hot-rolled steel strip manufactured by the method disclosed in the present invention. Since it disappears by recrystallization and grain growth during annealing, the magnetic flux density of the product cannot be sufficiently improved.

The technical idea of the manufacturing method involving this conventional hot rolling annealing is that crystal grains having {111} planes in parallel with the plate surface that hinder the improvement of magnetic flux density by increasing the crystal grain size before cold rolling. It was to increase the abundance of crystal grains having {110} <001> orientation.
For this reason, it is completely different from the technical idea of the present invention in which the magnetic flux density of the product is improved by directly utilizing the texture of the hot-rolled steel strip controlled by finish hot rolling.

The inventors have also clarified that the magnetic flux density of the product decreases even if the hot rolling start temperature and hot rolling end temperature for achieving this object are too low.
That is, the inventors have clarified that there is a range of optimum hot rolling start temperature and hot rolling end temperature for controlling the texture of the hot rolled steel strip intended by the present invention.

  In addition, when the amount of C in the steel exceeds the range specified in the present invention, it is significantly impeded to create a texture suitable for improving the magnetic flux density of the product by hot rolling in the hot rolled steel strip, and the magnetic flux density of the product. The inventors have also found as a new finding that the remarkably decreases.

  The hot-rolled steel strip after finishing hot rolling is pickled and cold-rolled to the final thickness. The cold-rolled steel strip after cold rolling is recrystallized by finish annealing to obtain a finished product. This product may be used without being subjected to strain relief annealing, or may be used after being applied, or may be used after being subjected to strain relief annealing after being shaped through a punching process.

  The temperature range of finish annealing needs to be performed in the α phase range because it is necessary to form an appropriate recrystallized texture to increase the magnetic flux density during finish annealing from the texture built into the hot-rolled steel strip. . That is, when the finish annealing temperature exceeds the Ac1 point which is the upper limit of the α phase region, the magnetic flux density of the product is lowered. Therefore, the finish annealing temperature needs to be performed at the Ac1 point or less within the α phase.

If the final annealing time is less than 10 seconds, recrystallization is insufficient and a high magnetic flux density cannot be obtained. On the other hand, when the finish annealing time exceeds 3 minutes, the productivity is deteriorated and the cost is increased. Therefore, the finish annealing time is preferably within 3 minutes.
Thereby, it becomes possible to manufacture a non-oriented electrical steel sheet having a high magnetic flux density at a lower cost than before.

  The high magnetic flux density non-oriented electrical steel sheet obtained by the present invention is most suitable for electrical equipment that is required to be small and light, iron cores of rotating machines, and small transformers, but also various compressors, generators, high output It is suitable for iron core applications such as motors for electric vehicles that require high power.

  In the present invention, a pole figure is used for the definition of the invention, and α and β are used as a method of representing the position in the pole figure. These are angles, α indicates a direction from the center of the pole figure toward the outer periphery, and β indicates a circumferential direction. On the pole figure, α uses a range of 0 ° to 90 °, and β uses a range of 0 to 360 °. 0 ° of β is the same as 360 ° as described later.

  For the α angle, the center of the pole figure is α = 0 °, and the outer periphery of the pole figure is α = 90 °. The α angle is the same on a concentric circle centered on the center of the pole figure. Since the distribution of α angles on the pole figure is determined by the stereo projection method and is not equidistant, the scale is shown every 10 ° on the vertical and horizontal axes of the pole figure.

  For the β angle, the RD direction, which is the rolling direction on the pole figure, is set to 0 °, and the vertical line passing through the center of the pole figure is divided into 360 parts evenly in the clockwise direction around the rotation axis. Accordingly, the β angle on the pole figure is expressed as an angle clockwise from the RD direction of the pole figure. The β angle of 360 ° is the same position as the β angle of 0 ° because it is the position reached in the original RD direction even after one round from the RD direction.

  In the present invention, the Miller index is used to represent the crystal orientation, and the second method of the new edition X-ray diffraction theory published in June 1980 by Agne Co., Ltd. was published by Karity. Follow the method described in the chapter.

Next, reasons for limitation of claims 2 and 3 will be described with reference to FIGS.
1 and 2 are (100) pole figures obtained by measuring the non-oriented electrical steel sheet produced by the method of the present invention shown in Example 1 by X-ray diffraction.

  In FIG. 1, in the (100) pole figure from the surface layer of steel plate to 1 / 10th layer in the plate thickness direction, α = 90 ° and β are β = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, respectively. , 300 °, 330 ° points are indicated by ● marks. These positions belong to the crystal orientation in which the {100} plane of the bcc iron crystal is parallel to the steel plate surface on the periphery of the (100) pole figure.

If all of the strengths in the pole figures at these eight positions are 1.0 or more, there is a crystal orientation in which the magnetic flux flowing in the plate surface coincides with the easy magnetization direction of the bcc iron crystal when the steel plate is magnetized. The flow of magnetic flux in the steel sheet is improved and the magnetic properties are improved.
That is, since the strengths of these eight positions are all 1.0 or more, the flow of magnetic flux in more directions in the steel sheet is improved, and at the same time the magnetic characteristics under the rotating magnetic flux are also improved. Specify 0 or more.

  On the other hand, if the strength of some or all of these eight positions is less than 1.0, the flow of magnetic flux in the steel sheet becomes difficult, and the magnetic flux density decreases and the iron loss increases. Stipulated in

In addition, in the (100) pole figure of FIG. 1, α = 80 ° and β are β = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, 330 °, respectively. It showed in. In these positions, the {100} plane is inclined by 10 ° with respect to the steel plate surface, but the {100} plane is close to the crystal orientation parallel to the steel plate surface and belongs to a crystal orientation in which the flow of magnetic flux in the steel plate is good.
For this reason, if the strengths of the eight positions on the (100) pole figure are all 1.0 or more, the magnetic characteristics are improved, the magnetic flux density is increased, and the iron loss is reduced. The strength of all is specified to be 1.0 or more.

Since the strength of these eight positions is all 1.0 or more, the flow of magnetic flux in more directions in the steel sheet is improved, and at the same time, the magnetic characteristics under the rotating magnetic flux are also improved. Stipulate.
On the other hand, if the strength of some or all of these eight positions is less than 1.0, the flow of magnetic flux in the steel sheet becomes difficult, and the magnetic flux density decreases and the iron loss increases. Determine.

  According to the study by the inventors, according to the present invention, the texture control effect of the product is firstly α = 80 ° and β = 30 °, 60 °, 120 °, 150 °, 210 ° on the (100) pole figure. , 240 °, 300 °, and 330 °, which are manifested by an increase in intensity, and then α = 90 ° and β = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, Strength of 8 points of 330 ° is improved.

  The magnetic characteristics are improved if the strength of all eight orientations where α = 80 ° is 1.0 or more, but more if the strength of all eight orientations where α = 90 ° is 1.0 or more. Good magnetic properties can be obtained.

  The effect of improving the magnetism is more remarkable when the strength at 8 points of α = 90 ° is improved. However, practically, it is easier to improve the degree of integration at 8 points of α = 80 °. The strengths were determined for 8 points of 80 ° = 80 °, and in claim 3, the strengths were determined for 8 points of α = 80 ° and 8 points of α = 90 ° as textures for obtaining more preferable magnetic properties.

  Further, in order to improve the workability of the non-oriented electrical steel sheet, 50 ° ≦ α ≦ 70 ° and β in the (100) pole figure of the half layer thickness direction center layer of the steel plate shown in FIG. It is necessary that there is a region having an intensity of 1.0 or more at all of the six locations defined by β = 0 °, 60 °, 120 °, 180 °, 240 °, and 300 °, respectively.

  In FIG. 2, these six regions are indicated by double-ended arrows. As a result, an increase in burrs during punching of a non-oriented electrical steel sheet can be suppressed, the roundness after punching can be improved, and the shape freezing property, r value, etc. in bending and drawing can be improved. A non-oriented electrical steel sheet excellent in both workability can be obtained.

  For this purpose, in the present invention, 50 ° ≦ α ≦ 70 ° and β is β = 0 °, 60 °, 120 °, 180 in the (100) pole figure of the half layer in the thickness direction center layer of the steel sheet. It is determined that there are regions having an intensity of 1.0 or more in all the six regions defined at °, 240 °, and 300 °. In FIG. 2, these six regions are indicated by double-ended arrows.

  If the strength is less than 1.0 in some or all of these six regions on the (100) pole figure of the (100) pole figure of the center layer in the plate thickness direction of the steel sheet, the burr at the time of punching increases. Further, since the roundness is lowered, the shape freezing property in bending work, drawing work, etc., and the r value is lowered to make the work difficult, it is necessary to have a region having a value of 1.0 or more in all 6 places.

  The present invention is characterized in that it is effective in improving magnetic properties to control the texture in the vicinity of the surface layer of a non-oriented electrical steel sheet so that the orientation that smoothes the flow of magnetic flux in the steel sheet is superior. There is. In that case, it discovered that the integration degree improvement of {411} azimuth | direction and {310} azimuth | direction was effective not only in {100} azimuth | direction in steel plate surface layer.

  Furthermore, the magnetic properties of non-oriented electrical steel sheets can be improved by controlling the ratio of the sum of the strengths of a specific orientation and the sum of the strengths of other specific orientations within a certain range as well as the absolute strength of a specific orientation. I found new findings.

  That is, as a texture that achieves excellent magnetic properties in a non-oriented electrical steel sheet, the strengths of the (100) plane, (411) plane, and (111) plane are measured as I ( 100), I (411), and I (111), I (100) ≧ 2.0 and I (411) ≧ 1.5 in the texture of 1/10 layer from the surface of the steel plate in the thickness direction. In addition, it has been found that the magnetic properties are excellent when I (111) ≦ 4.0 and {I (100) + I (411)} / I (111) ≧ 1.0.

  Further, when the strengths of the (310) plane, (332) plane, (211) plane, and (221) plane are I (310), I (332), I (211), and I (221), respectively, In the texture of 1/10 layer from the sheet thickness direction, I (100) ≧ 2.0, I (411) ≧ 1.5, I (111) ≦ 4.0, and {I (100) + I It has been found that when (411) + I (310)} / {I (111) + I (332) + I (211) + I (221)} ≧ 0.5, the magnetic characteristics are excellent.

  In bcc iron, the structural factors of the (100), (111), and (221) planes are zero, so the (200), (222), and (442) planes are the second-order diffraction planes. Measure each. As the surface index, (100), (111), and (221) are used, respectively.

  If the {I (100) + I (411)} / I (111) value is less than 1.0 in the 1/10 layer texture from the surface of the steel sheet, the iron loss increases and the magnetic flux density decreases. The value of {I (100) + I (411)} / I (111) is preferably 1.0 or more.

  Furthermore, {I (100) + I (411) + I (310)} / {I (111) + I (332) + I (211) + I (221)} in a 1/10 layer texture from the surface of the steel plate Is less than 0.5, the iron loss increases and the magnetic flux density decreases, so it is preferably 0.5 or more.

  If the I (100) and I (411) values are less than 2.0 and less than 1.5 in the 1/10 layer texture from the surface of the steel sheet, the magnetic flux density decreases. .5 or more is preferable. Further, if the value of I (111) is more than 4.0, the magnetic flux density is lowered, so that it is preferably 4.0 or less.

  Regarding the effect of the strength relationship between these orientations on the magnetic properties, by increasing the accumulation of {100}, {411} and {310} orientations near the surface layer, the crystal grains near the surface layer become non-oriented electrical steel sheets. It is assumed that the magnetic properties such as iron loss and magnetic flux density are improved because the magnetization in the direction perpendicular to the plate surface is suppressed and the flow of magnetic flux in the steel plate becomes smooth.

  Further, if the strength of {100} orientation and {411} orientation is insufficient, the amount of crystals that have an effective orientation for improving magnetic properties is insufficient, and the magnetic property improvement effect of the present invention is not achieved. I guess I can't get it.

  In addition, even when magnetic flux is unevenly distributed on the steel sheet surface due to the skin effect under high frequency excitation such as an inverter, the flow of magnetic flux in the steel sheet becomes smooth due to the improved texture of the steel sheet surface layer. It is speculated that it has become possible to achieve excellent magnetic properties.

As a method for further increasing the magnetic flux density of the non-oriented electrical steel sheet of the present invention, the inventors have found that it is effective to appropriately control the rolling rate in the cold rolling process. That is, since the effect of improving the magnetic flux density is significantly promoted at a cold rolling rate of 85% or more, the cold rolling rate is set to 85% or more.
On the other hand, in order to make the cold rolling rate over 95%, the burden on the cold rolling equipment becomes large, the cost is remarkably increased, and it is uneconomical. Therefore, the upper limit of the cold rolling rate is set to 95% or less.

  The inventors have found that the excellent properties of the non-oriented electrical steel sheet of the present invention are not accurately measured by the Epstein method that has been defined in JIS (Japanese Industrial Standard). That is, in the present invention, it has been found that when the direction of the plate collected by the Epstein method is 45 degrees to the left and right within the steel plate surface from the rolling direction, the magnetic properties are most excellent and the left and right magnetic properties are almost equal. It is.

  In the conventional JIS standard Epstein method, a sample is cut in half from the rolling direction and its perpendicular direction to create a closed magnetic path in the order of the rolling direction, the perpendicular direction, the rolling direction, and the perpendicular direction. Measure characteristics. However, in the non-oriented electrical steel sheet produced in the present invention, the rolling direction of the steel sheet and the direction perpendicular to the rolling direction are the directions in which the magnetic properties are inferior, and the direction deviated 45 degrees to the left and right within the steel sheet surface from the rolling direction is the most. It was newly found that the magnetic properties are excellent.

  By this novel discovery, in the present invention, when shearing when processing a steel sheet into an iron core, the direction in which the magnetic flux of the iron core flows is non-directional to match the direction inclined 45 degrees to the left and right within the steel sheet surface from the rolling direction of the steel sheet Shears the electrical steel sheet.

  If the direction in which the magnetic flux flows in the iron core deviates from the rolling direction of the steel sheet from a direction inclined 45 degrees to the left and right within the steel sheet surface, the magnetic properties of the product using the non-oriented electrical steel sheet can be fully utilized. Since this is not possible, it is necessary to shear the steel sheet so that the direction in which the magnetic flux flows coincides with the direction inclined 45 degrees to the left and right within the steel sheet surface.

  By using the non-oriented electrical steel sheet produced in this way, by adjusting the direction in which the magnetic flux flows to the direction inclined 45 degrees from the rolling direction within the plate surface of the steel sheet, the EI core, the rotary core split core, the transformer frame iron core, The direction of the small iron core, the core for the reactor, the yoke and teeth of the spiral core and the direction of easy magnetization of the non-oriented electrical steel sheet according to the present invention can be matched to improve the magnetic characteristics.

  Further, the non-oriented electrical steel sheet obtained by the present invention has the most excellent magnetic properties in a direction inclined 45 degrees to the left and right within the plate surface from the rolling direction. Therefore, the EI core, the split core for rotating machines, and the frame iron core for transformer Small magnetic cores, reactor cores, and smoothly flowing magnetic flux through the 90 ° corners inside the spiral core, reducing iron loss at the corners and reducing both the yoke and teeth at 90 ° angles At the same time, it has an excellent property of allowing a magnetic flux to flow smoothly.

  Thereby, when shearing the non-oriented electrical steel sheet produced in the present invention, the direction inclined 45 degrees from side to side in the plate surface from the rolling direction of the steel sheet to match the direction in which the magnetic flux of the iron core flows, By using this as a raw material, it is possible to obtain an EI core having excellent magnetic properties, a split core for a rotating machine, a frame iron core for a transformer, a small iron core, a core for a reactor, and a spiral core.

  The reason why the magnetic properties of the non-oriented electrical steel sheet obtained in the present invention are most excellent in the direction inclined 45 degrees to the left and right within the plate surface from the rolling direction cannot be explained from the pole figure of FIG. The inventors have been diligently investigating this point, but currently infer as follows.

  The reason why excellent magnetic properties can be obtained in the present invention is that, as shown in the pole figure of FIG. 1, in the texture of the surface layer, the <100> axis exists in a direction almost parallel to the plate surface. I guess. On the other hand, as shown in FIG. 2, the texture of the central layer is inferior to the magnetic property improvement of the present invention because <111>, which is a hard magnetization orientation, exists in parallel to the plate surface. Yes.

  Here, when explaining the pole figure and the magnetization of the polycrystalline body, the pole figure shows the orientation distribution of the polycrystalline grains, and the flow of magnetic flux in the individual grains in the polycrystalline steel sheet is shown. It is not shown. Therefore, in the non-oriented electrical steel sheet made of the polycrystalline material having the crystal orientation distribution shown in FIG. 1, the total sum of the magnetic flux flows of the individual crystals is not yet clear, but the sum of the magnetostatic energy of magnetization is not It is presumed that the magnetic properties in the 45 degree direction are the best in the plate surface because the 45 degree direction is minimized for some reason.

Next, examples of the present invention will be described.

A slab for non-oriented electrical steel having the components shown in Table 1 was heated at 800 ° C. for 1 hour by a normal method and finished to 2.5 mm by hot rolling. The finishing hot rolling start temperature was 750 ° C. The finishing hot rolling end temperature was changed in the range of 500 ° C. to 730 ° C. by controlling the rolling rate and the cooling rate between the hot rolling stands. The Ar1 transformation point of this steel is 880 ° C.
Subsequently, pickling was performed, and the product was finished to 0.5 mm by cold rolling, and this was subjected to finish annealing at 750 ° C. for 30 seconds in a continuous annealing furnace. Then, it cut | disconnected to the Epstein sample and measured the magnetic characteristic.

Table 1 shows the components, and Table 2 shows the measurement results of the relationship between the finish hot rolling end temperature and the magnetic properties.
From Table 2, it is possible to manufacture a non-oriented electrical steel sheet having a high magnetic flux density by appropriately controlling the finishing hot rolling end temperature and omitting costly processes such as hot-rolled sheet annealing.

Further, a sample for X-ray diffraction was prepared from the sample of the present invention 3 shown in Table 2, and 1/10 layer in the plate thickness direction from the surface layer and 1/2 layer in the plate thickness direction were exposed by polishing to expose X layer. A line diffraction measurement was performed to create a (100) complete pole figure. The results are shown in FIGS. 3 and 4, respectively.
In the (100) pole figure of one-tenth layer from the surface layer of the steel plate shown in FIG. 3, the accumulation near the {411} <148> orientation is high.

  Further, there is a region having a high intensity distribution from {411} <148> to the vicinity of the {100} <012> orientation on the outer periphery of the pole figure, and the intensity near the {100} <012> plane is 1.0 on the outer periphery of the pole figure. Alternatively, it reaches 1.5 and the {100} plane that is the cube orientation is enriched. In the vicinity of the {411} <148> orientation, the three locations exceed the maximum strength of 2.5, and one location exceeds the maximum strength of 2.0.

  In the (100) pole figure of the half layer, which is the center layer of the steel sheet shown in FIG. 4, the {111} axis called gamma fiber is parallel to the steel sheet surface and perpendicular to the steel sheet surface. A texture formed by crystal orientation groups rotating around has developed, and on the pole figure, a high strength region appears concentrically around α = 54.7 °. Among them, there is a feature that the accumulation in the vicinity of the six {111} <112> orientations is particularly high and the maximum intensity is 1.0 or more.

  The characteristics of the individual intensity distribution in the pole figure will be described. In the (100) pole figure in the thickness direction of 1/10 from the surface of the steel sheet shown in FIG. 3, α = 80 ° and β is β = The strengths at 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, and 330 ° are all 1.0 or more, and α = 90 ° and β is β on the same pole figure, respectively. = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, 330 ° All strengths are 1.0 or more, and the thickness direction central layer 2 of the steel sheet shown in FIG. In the (100) pole figure of one-layer, 50 ° ≦ α ≦ 70 ° and β is defined by α and β of β = 0 °, 60 °, 120 °, 180 °, 240 °, and 300 °, respectively 6 There is a feature that a region having an intensity of 1.0 or more exists in the entire range of the portion.

  As described above, in the present invention, the crystal orientation is accumulated near the cube orientation near the surface layer of the steel sheet, whereas the gamma fiber texture is developed in the steel sheet center layer, and the texture of the steel sheet surface layer and the steel sheet center layer is A big difference is a new feature.

  In order to compare the workability of the non-oriented electrical steel sheet produced by the method disclosed in the present invention and the non-oriented electrical steel sheet produced by the conventional technique, the slabs of the test materials shown in Table 1 were used at 1150 ° C. for 1 hour. Heating was performed, and the finish hot rolling start temperature was set to 1000 ° C. and the finish hot rolling end temperature was set to 860 ° C. to finish a 2.5 mm hot rolled sheet. Subsequently, pickling was performed, and the product was finished to 0.5 mm by cold rolling, and this was subjected to finish annealing at 750 ° C. for 30 seconds in a continuous annealing furnace. This sample was referred to as Comparative Example 2. Then, it cut | disconnected to the Epstein sample and measured the magnetic characteristic.

  A non-oriented electrical steel sheet of Comparative Example 1 and Comparative Example 2 and a non-oriented electrical steel sheet manufactured according to the present invention were subjected to a punching test into a shape having a diameter of 100 mm using a perfect circle mold according to Inventions 1 to 5. On the other hand, the edge height of the edge of the sample of the present invention was 20 μm or less after 500,000 times of punching, whereas the edge height of the edge in Comparative Example 1 and Comparative Example 2 exceeded 20 μm. .

Further, when the roundness was measured at the same time, in Comparative Examples 1 and 2, the roundness was more than 35 μm, while in the present invention 1 to the present invention 5, it was only 35 μm or less and showed a good value. It was. For the measurement of roundness, the difference between the diameters of a perfect circle inscribed and circumscribed in a round sample having a diameter of 100 mm after punching out of 500,000 times was expressed in μm.
These results are also shown in Table 2.

  As described above, the non-oriented electrical steel sheet produced according to the present invention has extremely low burr height and good roundness and excellent workability as a non-oriented electrical steel sheet containing 0.3% of Si. ing.

  According to the present invention, it is possible to increase the accumulation in the vicinity of the cube orientation in the steel sheet surface layer, so that when the steel sheet is excited, it is possible to reduce the magnetization component perpendicular to the steel sheet surface, which is effective in reducing iron loss. Since it is possible to increase the accumulation of gamma fiber texture in the central layer, it is possible to produce a non-oriented electrical steel sheet with excellent workability.

The slab for non-oriented electrical steel having the components of Steel 2 shown in Table 3 was heated at 750 ° C. for 1 hour by a normal method, and finished to 2.5 mm by hot rolling. The finishing hot rolling start temperature was changed in the range of 600 ° C to 740 ° C. The finishing hot rolling finish temperature was set to 560 ° C. by controlling the rolling speed and the cooling speed between the hot rolling stands.
The Ar1 transformation point of this steel is 867 ° C.

  Since sol-Al was not subjected to Al deoxidation or Al addition at the steelmaking stage, it was below the detection limit. In the analytical instrument used in this experiment, the detection limit of sol-Al was 0.001%, and sol-Al determined to be below this limit amount was described as “tr.” In the table. The same applies to the following embodiments.

  Subsequently, pickling was performed, and the product was finished to 0.5 mm by cold rolling, and this was subjected to finish annealing at 750 ° C. for 30 seconds in a continuous annealing furnace. Then, it cut | disconnected to the Epstein sample and measured the magnetic characteristic.

Table 3 shows the components, and Table 4 shows the measurement results of the relationship between the finish hot rolling end temperature and the magnetic properties.
From Table 4, it is possible to manufacture a non-oriented electrical steel sheet having a high magnetic flux density by appropriately controlling the finishing hot rolling start temperature and omitting costly processes such as hot rolled sheet annealing.

A slab for non-oriented electrical steel having the components shown in Table 5 was heated at 800 ° C. for 1 hour by a normal method and finished to 2.5 mm by hot rolling. The finishing hot rolling start temperature was 780 ° C., and the finishing hot rolling end temperature was controlled to 640 ° C. by controlling the rolling speed and the cooling rate between the hot rolling stands.
The Ar1 transformation point of these steels is 865 ° C to 878 ° C.

Next, pickling was performed and the product was finished to 0.5 mm by cold rolling, and this was subjected to finish annealing at 750 ° C. for 30 seconds in a continuous annealing furnace. Then, it cut | disconnected to the Epstein sample and measured the magnetic characteristic.
Table 5 shows the components of the present invention and the comparative example, and Table 6 shows the measurement results of the magnetic properties of each test material.

Thus, by controlling the C content to 0.004% or less and appropriately controlling the finish hot rolling conditions, costly processes such as hot-rolled sheet annealing are omitted, and high magnetic flux density non-directional electromagnetic It is possible to produce a steel plate.
Furthermore, it can be seen from Table 6 that, in particular, when the C content is 0.003% or less, the magnetic flux density B50 is higher than 1.8T. Furthermore, it can be seen that when the C content is 0.002% or less, a higher magnetic flux density with a B50 value of 1.815 T or more is obtained.

The slab for non-oriented electrical steel having the components of Steel 11 shown in Table 7 was heated at 1150 ° C. for 1 hour by a normal method and finished to 2.5 mm by hot rolling. The finishing hot rolling start temperature was changed in the range of 600 ° C to 870 ° C. The finishing hot rolling finish temperature was set to 560 ° C. by controlling the rolling speed and the cooling speed between the hot rolling stands.
The Ar1 transformation point of this steel is 865 ° C.

  Subsequently, pickling was performed, and the product was finished to 0.5 mm by cold rolling, and this was subjected to finish annealing at 750 ° C. for 30 seconds in a continuous annealing furnace. Then, it cut | disconnected to the Epstein sample and measured the magnetic characteristic.

  Table 7 shows the components, and Table 8 shows the measurement results of the relationship between the finish hot rolling end temperature and the magnetic properties.

  From Table 8, it is possible to produce a high-flux-density non-oriented electrical steel sheet while omitting costly processes such as hot-rolled sheet annealing by appropriately controlling the finishing hot-rolling start temperature.

The slab for non-oriented electrical steel having the components of steel 12 shown in Table 9 was heated at 900 ° C. for 1 hour by a usual method, and finished to 2.5 mm by hot rolling. The finishing hot rolling start temperature was changed in the range of 600 ° C to 870 ° C. The finishing hot rolling finish temperature was set to 560 ° C. by controlling the rolling speed and the cooling speed between the hot rolling stands.
The Ar1 transformation point of this steel is 868 ° C.

  Subsequently, pickling was performed, and the product was finished to 0.5 mm by cold rolling, and this was subjected to finish annealing at 750 ° C. for 30 seconds in a continuous annealing furnace. Then, it cut | disconnected to the Epstein sample and measured the magnetic characteristic.

Table 9 shows the components, and Table 10 shows the measurement results of the relationship between the finish hot rolling finish temperature and the magnetic properties.
From Table 10, it is possible to manufacture a non-oriented electrical steel sheet having a high magnetic flux density while omitting costly processes such as hot-rolled sheet annealing by appropriately controlling the finish hot-rolling start temperature.

The slab for non-oriented electrical steel having the components of Steel 13 shown in Table 11 was heated at 870 ° C. for 1 hour by a normal method and finished to 2.5 mm by hot rolling. The finishing hot rolling start temperature was changed in the range of 600 ° C to 860 ° C. The finishing hot rolling finish temperature was 565 ° C. by controlling the rolling speed and the cooling speed between the hot rolling stands.
The Ar1 transformation point of this steel is 866 ° C.

  Subsequently, pickling was performed, and the product was finished to 0.5 mm by cold rolling, and this was subjected to finish annealing at 750 ° C. for 30 seconds in a continuous annealing furnace. Then, it cut | disconnected to the Epstein sample and measured the magnetic characteristic.

Table 11 shows the components, and Table 12 shows the measurement results of the relationship between the finish hot rolling end temperature and the magnetic properties.
From Table 12, it is possible to produce a high-flux-density non-oriented electrical steel sheet while omitting costly processes such as hot-rolled sheet annealing by appropriately controlling the finish hot-rolling start temperature.

A slab for non-oriented electrical steel having the components shown in Table 13 was heated at 800 ° C. for 1 hour by a usual method, and finished to 2.5 mm by hot rolling. The finishing hot rolling start temperature was 730 ° C. The finishing hot rolling end temperature was set to 620 ° C. by controlling the rolling speed and the cooling speed between the hot rolling stands.
Subsequently, pickling was performed, and it was finished to 0.5 mm by cold rolling, and this was subjected to a finish annealing for 30 seconds at each temperature in a continuous annealing furnace. Then, it cut | disconnected to the Epstein sample and measured the magnetic characteristic.

Table 13 shows the components of the present invention and comparative examples, and Table 14 shows the measurement results of the relationship between the finish annealing temperature and the magnetic properties.
From Table 14, it is possible to produce a non-oriented electrical steel sheet having a high magnetic flux density by adjusting the Si and Al contents within the component ranges of the present invention.

The slab for non-oriented electrical steel having the components shown in Table 15 was heated at 800 ° C. for 1 hour by a usual method, and finished to 2.5 mm by hot rolling. The finishing hot rolling start temperature was 750 ° C. The finishing hot rolling end temperature was set to 630 ° C. by controlling the rolling rate and the cooling rate between the hot rolling stands.
As Comparative Example 3, a slab having the same components as in Table 15 was heated at 1150 ° C. for 1 hour, the finish hot rolling start temperature was 1000 ° C., the finish hot rolling end temperature was 860 ° C., and a 2.5 mm hot rolled plate. Finished.

Subsequently, pickling was performed, and the product was finished to 0.5 mm by cold rolling, and this was subjected to finish annealing at 750 ° C. for 30 seconds in a continuous annealing furnace. Then, it cut | disconnected to the Epstein sample and measured the magnetic characteristic.
Further, the texture of one-tenth layer in the thickness direction from the surface of the sample of the inventive example and the comparative example 3 was measured by an inverse pole figure by X-ray diffraction, and the reflection surface intensity of each diffraction surface was measured.

Table 15 shows the components of the present invention and comparative examples, Table 16 shows the magnetic property measurement results, Table 17 shows the texture measurement results by X-ray diffraction, and Tables 18 and 19 show the texture determination results.
From Table 16, it can be seen that the production method of the present invention can produce a non-oriented electrical steel sheet having low iron loss and high magnetic flux density at commercial frequencies and excellent iron loss at commercial frequencies and high frequencies. .

  Also, from Table 18, the intensities of the (100) plane, (411) plane, and (111) plane in the inverted pole figure obtained by X-ray diffraction measurement are I (100), I (411), and I (111), respectively. Then, in the present invention, I (100) ≧ 2.0, I (411) ≧ 1.5, and I (111) ≦ 4. 0 and {I (100) + I (411)} / I (111) ≧ 1.0.

  Furthermore, from Table 19, when the strengths of the (310) plane, (332) plane, (211) plane, and (221) plane are I (310), I (332), I (211), and I (221), respectively. In the present invention, I (100) ≧ 2.0, I (411) ≧ 1.5, and I (111) ≦ 4.0 in a 1/10 layer texture from the surface of the steel plate. {I (100) + I (411) + I (310)} / {I (111) + I (332) + I (211) + I (221)} ≧ 0.5.

The slab for non-oriented electrical steel having the components shown in Table 20 was heated by a normal method at 800 ° C. for 1 hour and finished to 2.0 mm by hot rolling. The finishing hot rolling start temperature was 750 ° C. The finishing hot rolling end temperature was set to 630 ° C. by controlling the rolling rate and the cooling rate between the hot rolling stands.
Subsequently, pickling was performed, finishing from 0.10 mm to 0.50 mm by cold rolling, and finish annealing at 750 ° C. for 25 seconds in a continuous annealing furnace. Then, it cut | disconnected to the Epstein sample and measured the magnetic characteristic. Cold rolling of 0.10 mm or less was not performed because the cost increased and the profitability decreased.

  As Comparative Example 4, a slab having the same components as in Table 20 was heated at 1150 ° C. for 1 hour, and after rough rolling, the finish hot rolling start temperature was 1000 ° C., and the finish hot rolling end temperature was 860 ° C. and 2.5 mm. The hot-rolled sheet was finished to a thickness of 0.50 mm at a cold rolling rate of 80% and subjected to finish annealing at 750 ° C. for 25 seconds. Then, it cut | disconnected to the Epstein sample and measured the magnetic characteristic.

Table 21 shows the measurement results of magnetic characteristics. In the example of the present invention in which the cold rolling rate is controlled from 85% to 95%, the magnetic flux density B50 has an excellent value of 1.84 T or more. The value of W15 / 50, which is the iron loss at a commercial frequency of 50 Hz, is also superior to the comparative example. Furthermore, the value of W10 / 400, which is the iron loss at a high frequency of 400 Hz and an operating magnetic flux density of 1.0 T, is also an excellent value as a component-based non-oriented electrical steel sheet having a Si content of 0.15%.
The inventors speculate that the improvement in the magnetic properties is caused by the improvement of the texture of the product compared to the prior art based on the measurement results of the texture described above.

  As described above, from Table 21, it is possible to produce a non-oriented electrical steel sheet with high magnetic flux density and low iron loss at commercial frequencies at a cold rolling rate of 85% to 95% and excellent iron loss at high frequencies. It can be seen that it is.

  Using a non-oriented electrical steel slab having the components shown in Table 22, process A steel and process B steel were produced.

As process A steel, a slab for non-oriented electrical steel having the components shown in Table 22 was heated by a normal method at 800 ° C. for 1 hour and finished to 2.0 mm by hot rolling. The finishing hot rolling start temperature was 750 ° C. The finishing hot rolling end temperature was set to 630 ° C. by controlling the rolling rate and the cooling rate between the hot rolling stands.
Subsequently, pickling was performed, and the film was finished to 0.30 mm by cold rolling, and finish annealing was performed at 750 ° C. for 25 seconds in a continuous annealing furnace. Thereafter, Epstein sample in the rolling direction, the direction inclined 22.5 degrees left and right from the rolling direction, the direction inclined 45 degrees left and right from the rolling direction, the direction 67.5 degrees from the rolling direction, and the direction inclined perpendicular to the rolling direction The magnetic properties were measured.

  Further, as a comparative example, the process B steel was heated at 1150 ° C. for 1 hour with a slab having the same components as in Table 22, and after rough rolling, the finish hot rolling start temperature was 1000 ° C., and the finish hot rolling end temperature was 860 ° C. As a hot rolled sheet having a thickness of 2.0 mm, followed by pickling, finishing to 0.30 mm, and finishing annealing at 750 ° C. for 25 seconds. Then, it cut | disconnected to the Epstein sample of the same angle as the above, and measured the magnetic characteristic.

  In addition to the method using the rolling direction specified by JIS and its perpendicular direction, the magnetic properties are measured using only samples in each shearing direction, and samples that are inclined 45 degrees to the left and right from the rolling direction are alternately stacked. ,It was measured. The notation of the direction of the sample is 0 °, 22.5 ° to the right, 22.5 ° to the left, 45 ° to the right, 45 ° to the left, 67.5 ° to the right and 67.5 ° to the left at an angle interval of 22.5 degrees. Expressed at 5 ° and 90 °.

  When examined beforehand, right 22.5 ° and left 22.5 °, right 45 ° and left 45 °, right 67.5 ° and left 67.5 ° showed almost the same measured values, and they were symmetrical in the rolling direction. Therefore, right 45 ° and left 45 ° samples were collected separately, right 22.5 ° and left 22.5 ° were right 22.5 °, right 67.5 ° and left 67.5 ° were right. Only a sample of 67.5 ° was collected, and the description on the right was omitted. In addition, measurement was performed with 45 ° right and 45 ° opposite to each other and a JIS sample rotated by 45 °, and the result was 45 ° right + 45 ° left.

Table 23 shows the measurement results of magnetic characteristics.
It can be seen from Table 23 that excellent magnetic properties can be obtained according to the present invention.

From the process A steel produced in Example 10, the EI core was punched with the EI direction aligned with the steel plate rolling direction, and the EI I direction was punched from the direction forming an angle of 45 ° with the steel plate rolling direction. An EI core was prepared, and an exciting coil was wound around the three legs of the E core, and the iron loss was measured. An H coil was installed in contact with the middle leg, and an exciting coil was wound thereon to measure the magnetic field.
FIG. 5 shows a schematic diagram of an EI core punched by the method of the present invention and a comparative example.

Also, a transformer core iron, a small transformer, a reactor iron core, and a small iron core having an outer diameter of 40 mm × 40 mm and an inner opening of 20 mm × 20 mm were punched for measuring magnetic characteristics of the spiral core. At that time, the two-way leg of the iron core that forms a right angle coincides with the rolling direction of the steel sheet and the perpendicular direction in the plate surface, and the two-way leg punches in a direction that forms 45 ° with the rolling direction of the steel sheet. Two types of iron cores were created by punching the iron core. The iron core was wound with 200 turns, and the iron loss was measured by a current method.
FIG. 6 shows a schematic diagram of a frame core punched out by the method of the present invention and a comparative example.

Next, a split core having an outer diameter of 150 mm consisting of 12 slots was prepared, and the teeth were wound and assembled, the rotor was incorporated, and the iron loss with a constant excitation magnetic field was measured. At that time, there were prepared one in which the teeth of the split core were punched in a direction perpendicular to the rolling direction of the steel sheet, and one in which the teeth were punched in a direction of 45 ° with the rolling direction of the steel sheet.
FIG. 7 shows a schematic diagram of a split core punched out by the method of the present invention and a comparative example.

Next, a spiral core having an outer diameter of 120 mm and a stacking thickness of 15 mm consisting of 40 slots was prepared, and the iron loss during excitation was measured. The core was manufactured by processing a 40-slot yoke into a circular shape and then laminating it. When punching, magnetic properties are obtained by punching the yoke in the rolling direction, teeth forming a direction perpendicular to the rolling direction and the rolling direction, and both the yoke and teeth forming a 45 ° direction from the rolling direction to the plate surface. Compared.
FIG. 8 shows a schematic diagram of a spiral core punched out by the method of the present invention and a comparative example.

  From Table 24, it can be seen that all iron cores punched by the method of the present invention have excellent magnetic properties.

Claims (7)

% By weight in steel
0.1% ≦ Si ≦ 2.0%,
Al ≦ 1.0%,
And 0.1% ≦ Si + 2Al ≦ 2.0% is satisfied,
C ≦ 0.004%,
S ≦ 0.003%,
N ≦ 0.003%
Steel, the balance being Fe and unavoidable impurities as slabs, hot rolling to rough rolling and subsequent hot rolling to form hot rolled sheets, pickling and a single cold rolling step In the manufacturing method of the non-oriented electrical steel sheet that performs finish annealing,
A method for producing a non-oriented electrical steel sheet having a high magnetic flux density, characterized in that a slab heating temperature ST, a finishing hot rolling start temperature F0T, and a finishing hot rolling end temperature FT of hot rolling are determined as follows.
700 ℃ ≦ ST ≦ 1150 ℃
650 ℃ ≦ F0T ≦ 850 ℃
550 ℃ ≦ FT ≦ 800 ℃ In the (100) pole figure created by X-ray diffraction measurement in 1 / 10th layer in the plate thickness direction from the surface of the steel plate,
α = 80 ° and β are respectively β = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, 330 °, and the strengths are all 1.0 or more,
And in the (100) pole figure measured by X-ray diffraction measurement in the half layer thickness direction center layer of the steel plate,
There is a region where the intensity is 1.0 or more in the regions of α and β where 50 ° ≦ α ≦ 70 ° and β is determined by β = 0 °, 60 °, 120 °, 180 °, 240 °, and 300 °, respectively. A non-oriented electrical steel sheet characterized by: In the (100) pole figure created by X-ray diffraction measurement in 1 / 10th layer in the plate thickness direction from the surface of the steel plate,
α = 80 ° and β are β = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, 330 °, all of strengths of 1.0 or more, and on the same pole figure, α = 90 ° and β are respectively β = 30 °, 60 °, 120 °, 150 °, 210 °, 240 °, 300 °, 330 °, and the strengths are all 1.0 or more,
And in the (100) pole figure created by X-ray diffraction measurement in the half layer which is the center layer in the plate thickness direction of the steel plate,
There is a region where the intensity is 1.0 or more in the regions of α and β where 50 ° ≦ α ≦ 70 ° and β is determined by β = 0 °, 60 °, 120 °, 180 °, 240 °, and 300 °, respectively. A non-oriented electrical steel sheet characterized by: The strengths of the (100) plane, (411) plane, and (111) plane in the inverse pole figure obtained by X-ray diffraction measurement at 1 / 10th layer in the thickness direction from the surface of the steel sheet are I (100) and I (411), I (111)
I (100) ≧ 2.0
I (411) ≧ 1.5
I (111) ≦ 4.0
And,
{I (100) + I (411)} / I (111) ≧ 1.0
A non-oriented electrical steel sheet characterized by satisfying   The method for producing a non-oriented electrical steel sheet according to claim 1, wherein a rolling rate in cold rolling is 85% or more and 95% or less.   The magnetic steel sheet produced by the method for producing a non-oriented electrical steel sheet according to claim 1 or 5 or the magnetic steel sheet according to any one of claims 2 to 4 at the time of shearing when the magnetic steel sheet is processed into an iron core, A shearing method for a non-oriented electrical steel sheet, wherein the flowing direction is made to coincide with a direction inclined 45 degrees to the left and right within the steel sheet surface from the rolling direction of the steel sheet.   An electromagnetic component manufactured by a non-oriented electrical steel sheet manufactured by the method according to claim 6, wherein the electromagnetic component is an EI core, a split core for a rotating machine, a frame iron core for a transformer, a small iron core, a core for a reactor, An electromagnetic component that is one of a spiral core.

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