KR101507942B1 - Non-oriented electrical steel steet and method for the same - Google Patents

Abstract

The present invention relates to a non-oriented electrical steel sheet and a method of manufacturing the same. The steel sheet comprises 0.005% or less of C, 1.0 to 3.5% of Si, 0.2% or less of Al, 1.0 to 3.0% of Mn, 0.005 to 0.15 of P 0.001 to 0.005% of N, 0.001 to 0.005% of S, 0.005% or less of Ti, 0.01 to 0.2% of Sn + Sb and the balance Fe and other inevitably added impurities. A non-oriented electrical steel sheet satisfying a composition formula and a method of manufacturing the same are disclosed.
(0.5 * [Si] + [Al])? [Mn]? ([Si] + [Al]
[Si], [Al], and [Mn] in the above composition formula represent the weight percentages of Si, Al, and Mn, respectively.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a non-oriented electrical steel sheet,

The present invention relates to a non-oriented electrical steel sheet and a method of manufacturing the same, and more particularly, to a non-oriented electrical steel sheet having improved workability and magnetism by controlling the annealing temperature of a cold- And a manufacturing method thereof.

The non-oriented electrical steel sheet is used as a material for iron cores in rotating equipment such as induction machine and motor, and stationary equipment such as small-sized transformer. Since the energy loss of electric equipment is important in energy conversion, non-oriented electrical steel plays a very important role in determining energy efficiency. Recently, the demand for the reduction of energy and the miniaturization of electric equipment has increased, and it is necessary to improve the characteristics of the non-oriented electrical steel sheet.

The good magnetic properties of the electric steel sheet means that the iron loss is small and the magnetic flux density is high. When the magnetic field is induced by adding electricity to the iron core, the lower the iron loss, the lower the energy loss by heat and the higher the magnetic flux density This is because the same energy can induce a larger magnetic field.

In addition, there is an increasing demand for non-oriented electric steel sheets that have good magnetic properties as well as good workability. Since electric steel sheets are basically Si and Al as main additive elements, they are not good in workability. A non-oriented electrical steel sheet excellent in magnetic properties and excellent in workability is required because it is difficult or expensive.

Among the magnetic properties of the non-oriented electrical steel sheet, iron loss is composed of hysteresis loss, classical eddy current, and anomalous eddy current loss. In order to reduce iron loss, A method of reducing the classical eddy loss by increasing the electrical resistance by adding Si, Al or the like, which is a large alloying element, is used. However, addition of the alloying element reduces the iron loss, but also decreases the magnetic flux density due to the decrease of the saturation magnetic flux density.

On the other hand, when the amount of Si added is more than 4%, the workability is lowered and the cold rolling becomes difficult and the productivity is lowered. In addition to Si and Al, which is a main additive element, the rolling property decreases and the hardness increases and the workability decreases.

As a result, in order to obtain excellent magnetic properties in the production of a non-oriented electrical steel sheet, a method of reducing iron loss by adding an element that increases the resistivity of Si or Al has been used. However, due to the decrease of magnetic flux density and the increase of hardness There is a problem that the workability is reduced.

In order to improve the workability of such a non-oriented electrical steel sheet, a technique of adjusting the grain size through controlling the Si addition amount and the Al addition amount or controlling the annealing temperature is used. However, since all of these techniques can not solve the problem of lowering the magnetic properties, a non-oriented electrical steel sheet manufacturing technology having excellent workability and excellent magnetic properties is required.

There have been continuous efforts to solve these problems and many technologies have been developed. Japanese Patent Application No. 2008-045151 discloses a method of manufacturing a non-oriented electrical steel sheet in which the composition ratio of Si, Al, and Mn is controlled and the annealing temperature and the cold rolling reduction ratio of the hot-rolled steel sheet are controlled to reduce magnetic anisotropy and workability. However, there is a problem that the cost is increased by adding the step of performing the skin pass rolling after the final recrystallization annealing and performing the annealing again.

In order to solve the above-mentioned problems, the present invention provides a non-oriented electrical steel sheet in which Si, Al, and Mn are added to steel alloying elements and annealed in austenite-ferrite abnormal region during annealing of cold rolled steel sheet, .

In one or more embodiments of the present invention, it is preferable that the alloy contains 0.005% or less of C, 1.0 to 3.5% of Si, 0.2% or less of Al, 1.0 to 3.0% of Mn, 0.005 to 0.15% 0.001 to 0.005% of S, 0.005% or less of Ti, 0.01 to 0.2% of Sn + Sb, and the balance of Fe and other inevitably added impurities, wherein Si, Al and Mn satisfy the following composition formula A directional electrical steel sheet may be provided.

(0.5 * [Si] + [Al])? [Mn]? ([Si] + [Al]

[Si], [Al], and [Mn] in the above composition formula represent the weight percentages of Si, Al, and Mn, respectively.

When the volume percentages of the {100}, {111}, and {112} texture of the 3 / 4t portion of the steel sheet thickness are V _{100}, V _{{111}, and} V _{112} , V _{100} 20%, (V _{111} + V _{112} ), ≪ / = 65%.

The hardness of the steel sheet may be 190 Hv or less, Cu, Ni and Cr may each be added in an amount of 0.05 weight% or less, and Zr, Mo and V may be added in an amount of 0.01 weight% or less, respectively.

In one or more embodiments of the present invention, the steel sheet may contain 0.005% or less of C, 1.0 to 3.5% of Si, 0.2% or less of Al, 1.0 to 3.0% of Mn, 0.005 to 0.15% : 0.005% or less, S: 0.001 to 0.005%, Ti: 0.005% or less, Sn + Sb: 0.01 to 0.2% The balance Fe and other inevitably added impurities, To form a slab; Reheating the slab to 1200 ° C or less; Subjecting the reheated slab to hot rolling and annealing the hot-rolled sheet; A step of cold-rolling the annealed hot-rolled sheet two times by cold-rolling one time or intermediate annealing, and performing a cold-rolled sheet annealing in an abnormal region of austenite and ferrite at 850 to 1000 ° C. A method can be provided.

(0.5 * [Si] + [Al])? [Mn]? ([Si] + [Al]

And the hot-rolled sheet annealing is performed in a range of 850 to 1150 ° C.

At this time, Cu, Ni and Cr may each be added in an amount of 0.05 wt% or less, and Zr, Mo and V may be added in an amount of 0.01 wt% or less, respectively.

According to the embodiment of the present invention, by improving the texture and improving the workability and magnetic properties of the non-oriented electrical steel sheet by optimizing the additive components of Si, Al, and Mn and performing annealing of the cold rolled steel sheet in the two- .

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described in detail below. However, it is to be understood that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It is intended that the disclosure of the present invention be limited only by the terms of the appended claims.

An embodiment according to the present invention relates to a non-oriented electrical steel sheet and a method of manufacturing the same, wherein the addition amount of Si, Al and Mn is strictly controlled in a component system to which Si, Al and Mn are added, %, And the addition amount of Mn is controlled to 1.0 to 3.0%, the amount of Al, which is a relatively light metal, is decreased and the Mn addition amount is controlled to be high, And a technique for improving workability and magnetism by improving the texture by heat treatment in a two phase region including a phase transition phase during annealing of a cold rolled steel sheet.

The electric steel sheet according to the present invention is characterized in that it contains 0.005% or less of C, 1.0 to 3.5% of Si, 0.2 to 4.0% of Al, 1.0 to 3.0% of Mn, 0.005 to 0.15% of P, 0.005% or less, S: 0.001% to 0.005%, Ti: 0.005% or less, the balance Fe and other inevitably added impurities, and Si, Al and Mn satisfy the following composition formula (1).

(0.5 * [Si] + [Al])? [Mn]? ([Si] + [Al]

[Si], [Al], and [Mn] in the above composition formula (1) indicate the addition amounts of Si, Al, and Mn.

In the embodiment of the present invention, Sn and Sb may be added alone or in combination so that Sn + Sb is 0.01 to 0.2%

In the practice of the present invention, the cold-rolled sheet is subjected to heat treatment in an abnormal section including a phase transformation region upon annealing of the cold-rolled sheet, so that the microhardness of the final product is 190 Hv or less. In the embodiment according to the present invention, when the fractions of the {100}, {110}, and {111} texture are V _{100} , V _{110} , and V _{{111} in the} texture of the steel sheet after cold- , fraction V _{100} ≤ 20% of the {100} texture ({111} + {112}) fraction (V + V _{(111) {112})} of texture ≤ 65%.

Hereinafter, the reason for restricting the components in the embodiment according to the present invention described above will be described. Unless otherwise stated, units are percent by weight.

Si: 1.0 to 3.5 wt%

Since Si is a component which increases the resistivity of steel and lowers vortex loss during iron loss, it is difficult to obtain a low iron loss property when it is less than 1.0% and it is difficult to obtain low iron loss property when it is added. When it exceeds 3.5%, Si breaks during cold rolling, In the embodiment according to the invention, the content of Si is limited to 1.0 to 3.5% by weight.

Al: 0.2 wt% or less

Al is an element added inevitably for the deoxidation of steel during steelmaking and is added to lower the iron loss because it is a main element for increasing the resistivity, but it also serves to decrease the saturation magnetic flux density when added and also to make the workability worse In the embodiment according to the present invention, the content of Al is limited to 0.2% or less.

Mn: 1.0 to 3.0 wt%

Although the Mn has an effect of lowering the iron loss by increasing the resistivity, it is added with the aim of improving the iron loss by 0.1 to 0.3% in general, since the resistivity is less than that of Si and Al.

However, Mn is a soft metal compared to Si and Al and is an element that can improve workability and is an element that can improve the texture when the amount of addition is increased. Therefore, in order to improve the workability and texture, the Mn content in the examples according to the present invention is limited to 1.0 to 3.0%.

P: 0.005 to 0.15 wt%

The P increases the resistivity to lower the iron loss and segregates in the grain boundaries to inhibit the formation of {111} texture which is harmful to the magnetism and form {100} which is an advantageous aggregate structure. However, if 0.15% , The P content is limited to 0.005 to 0.15% by weight.

C: 0.005 wt% or less

When C is added in large amount, C shows the effect of suppressing the crystal growth of ferrite during annealing and enhances the iron loss. It forms a carbide by binding with Ti, etc., and dislocates the magnetism. In the final product, The C content in the examples according to the present invention is limited to 0.005% or less.

S: 0.001 to 0.005 wt%

Since S is an element which forms sulfides such as MnS, CuS and (Cu, Mn) S harmful to the magnetic properties, it is preferably added as low as possible. However, when it is added in an amount of less than 0.001%, it is disadvantageous to formation of aggregate structure, resulting in deterioration of magnetism. Therefore, it is contained in an amount of not less than 0.001%, and when it is added in an amount of more than 0.005%, the magnetism is heated due to increase of fine sulfides. In the examples, the S content is limited to 0.001 to 0.005%.

N: 0.005 wt% or less

Since N is an element which is harmful to magnetism by forming a nitride by binding strongly with Al, Ti or the like to inhibit crystal growth, it is preferable to contain N in a small amount, and therefore it is limited to 0.005 wt% or less in the examples according to the present invention.

Ti: 0.005 wt% or less

The Ti forms fine carbides and nitrides to inhibit crystal growth. The more the Ti is added, the lower the magnetization becomes because of the increased carbides and nitrides due to the increased carbides and nitrides. Therefore, in the embodiment of the present invention, the Ti content is limited to 0.005% or less do.

Sn + Sb: 0.01 to 0.2 wt%

The Sn and Sb suppress the diffusion of nitrogen through the grain boundaries as a segregated element in the grain boundaries, suppress the {111} texture which is harmful to the magnetism, increase the {100} When Sn or Sb alone or in excess of 0.2% is added, the crystal growth is inhibited and the magnetic property is deteriorated and the rolling property deteriorates. Therefore, in the embodiment of the present invention, the content of Sn + Sb is set to 0.01 to 0.2% It limits.

In addition to the above elements, Cu, Ni, and Cr, which are inevitably added in the steelmaking process, react with impurity elements to form fine sulfides, carbides, and nitrides, thereby detrimentally affecting the magnetic properties. Limit. Further, Zr, Mo, V and the like are preferably strong carbonitride-forming elements, so that they are preferably not added, and they are contained in an amount of 0.01 wt% or less.

In addition to the above composition, the remainder is composed of Fe and other unavoidable impurities.

In the embodiment according to the present invention, a method of manufacturing an electrical steel sheet for achieving the above object is presented, which will be described below.

First, 0.005% or less of C, 1.0 to 3.5% of Si, 0.2% or less of Al, 1.0 to 3.0% of Mn, 0.005 to 0.15% of P, 0.005% or less of N and 0.001 to 0.005 of S % Of Ti, 0.005% or less of Ti, 0.01 to 0.2% of Sn + Sb, and the balance of Fe and other inevitably added impurities and satisfies the following composition formula (1). When the reheating temperature is 1200 ° C or higher, the precipitates such as AlN and MnS present in the slab are reused, and are finely precipitated by hot rolling, annealing of hot-rolled steel sheet or annealing of cold rolled steel sheet to suppress grain growth and decrease magnetism. .

Then, the hot-rolled and hot-rolled hot-rolled sheet is subjected to hot-rolled sheet annealing if necessary, and the annealing temperature of the hot-rolled sheet is set to 850 to 1150 ° C. After pickling, cold rolling is finally rolled to a thickness of 0.10 mm to 0.70 mm, The rolled cold-rolled sheet is annealed at a temperature of 850 to 1000 ° C, and finally annealed in an abnormal region including a phase transformation.

At this time, finish rolling in finish rolling in hot rolling finishes on ferrite, and final reduction is made to be 20% or less for plate shape calibration.

The hot-rolled sheet prepared as described above is rolled up at 700 ° C or less and cooled in air. The rolled hot-rolled sheet, if necessary, is subjected to hot-rolled sheet annealing, pickling, cold-rolling, and finally cold-rolled sheet annealing.

The hot-rolled sheet annealing is to anneal the hot-rolled sheet when necessary for improving the magnetic properties, and the hot-rolled sheet annealing temperature is 850 to 1150 ° C. If the annealing temperature of the hot-rolled sheet is lower than 850 ° C, the grain growth is insufficient. When the annealing temperature exceeds 1150 ° C, the crystal grains excessively grow and the surface defects of the plate become excessive. Therefore, The temperature is limited to 850 ~ 1150 ℃.

Thereafter, the hot rolled sheet picked up by the ordinary method or the annealed hot rolled sheet is cold-rolled.

The cold rolling is final rolled to a thickness of 0.10 mm to 0.70 mm, and if necessary, can be subjected to primary cold rolling and secondary cold rolling after intermediate annealing, and the final rolling reduction is in the range of 50 to 95%.

The final cold-rolled steel sheet is cold-rolled sheet annealed. In the step of annealing the cold rolled sheet, the annealing temperature of the cold rolled sheet during the annealing is in the range of 850 to 1000 占 폚, but in the abnormal region including the phase transformation. If the annealing temperature of the cold-rolled sheet is 850 ° C or lower, the grain growth is insufficient and the loss of the steel loss is increased, and the aggregate structure is not improved and the magnetic property is lowered. Therefore, The temperature is 850 to 1000 캜.

In the embodiment according to the present invention, important elements added are Si, Mn, Al or Sn, and Sb. Generally, Si and Al have been developed in the direction of increasing the addition amount in the production of the non-oriented electrical steel sheet because of increasing the specific resistance of the steel and decreasing the classical eddy loss among the iron loss. However, Si is a very brittle element. As the addition amount is increased, the rolling property is heated, so that the amount of Si is increased and the amount of Al is increased. However, Al also increases the mechanical properties of the steel due to the solid solution strengthening effect, so that the magnetism is improved but the workability is lowered.

In the examples according to the present invention, Mn is a metal that is lighter than Al and can increase the resistivity and improve the texture as the addition amount increases. Al and Mn are controlled to be 0.2% or less and 1.0 to 3.0%, respectively, and Si, Al and Mn are controlled to satisfy the above composition formula (1), and the phase transformation region (austenite and ferrite abnormal region) , The structure of the ferrite is cooled down as it is, and only the structure of the austenite is transformed into ferrite.

When annealing the cold rolled steel sheet, the crystal growth is difficult because the temperature is rather low. Therefore, the fraction of the {111} and {112} texture is relatively low at relatively high temperature. In addition, since the austenite structure is transformed into ferrite, the fraction of {111} and {112} texture is further lowered.

Accordingly, not only the workability is improved, but also the volume percentage of {100}, {111}, and {112} texture of the 3 / 4t portion of the steel sheet after annealing of the cold rolled steel sheet is V _{100} V _(111), V if the called _{112}, {100} fraction V _{100} ≤ 20% of texture ({111} + {112}) fraction (V ₍₁₁₁₎ + V _{112 of texture _}} ≤ 65%, whereby a non-oriented electrical steel sheet excellent in workability and magnetic properties can be obtained.

In the present invention, an X-ray pole figure measurement method was used as a method for analyzing the texture. (110), (200) and (211) pole figures were measured by an X-ray diffractometer and the results were {100}, {111}, {112} Was calculated.

Hereinafter, embodiments according to the present invention will be described in more detail.

In the examples according to the present invention, Al and Mn are controlled to 0.2% or less and 1.0 to 3.0%, respectively, because Al is an element that lowers the resistivity, but the magnetic flux density decreases as the addition amount increases. The addition amount is limited to 0.2%, and the decrease of the resistivity due to the decrease of Al addition amount can be compensated by increasing the Mn to 1.0 ~ 3.0%.

Further, the amount of addition of Si, Al, and Mn is controlled so as to satisfy the above composition formula (1), which forms a phase transition zone during heat treatment, and the aggregate structure can be improved in annealing the cold rolled steel sheet in an ideal region including a phase transformation to be. {111}, {111}, {111}, {111}, {111}, {111}, and {112} of the 3 / 4t portion of the thickness of the steel sheet, } V the volume percentage of each texture _{{100}, V {111}} , V { if it _{112} V {100} ≤ 20} %, (V {111} + V _{112} ) < / = 65%. In the case of a steel sheet which satisfies the above-mentioned conditions and satisfies the heat treatment conditions, {111} and {112} texture structures which are harmful to magnetism are reduced, magnetism is improved, and a technique different from a conventional technology for increasing {100} In order to clarify the technology, we limit the volume percentage of {100} texture.

Hereinafter, the present invention will be described in more detail with reference to Examples.

[Example 1]

The ingots were prepared by vacuum melting as shown in Table 1 below, and the influence of Si, Al, and Mn was investigated. Each steel ingot was heated at 1150 DEG C, hot rolled to a thickness of 2.3 mm, and then wound. The hot-rolled steel sheet wound and cooled in air was annealed at 1030 ° C for 2 minutes, pickled, cold-rolled to a thickness of 0.35 mm, and subjected to cold-rolled sheet annealing at 980 ° C for 150 seconds. The hardness (W _15/50 ) and the magnetic flux density (B ₅₀ ) were measured for each specimen by means of hardness and X-ray pole figure test. The results are shown in Table 2 below. .

Steel grade C Si Mn P S Al N Ti Sn Sb A1 0.0026 2.6 1.2 0.06 0.0033 0.12 0.0031 0.0008 0 0.06 A2 0.0027 3.3 2 0.03 0.0036 0.29 0.0019 0.0034 0.035 0 A3 0.0033 2.6 1.7 0.007 0.0042 0.01 0.0021 0.0019 0.031 0.041 A4 0.004 1.5 1.1 0.04 0.0037 0.1 0.0018 0.0031 0.02 0 A5 0.0014 3.2 2.7 0.04 0.0029 0.07 0.0015 0.0009 0 0.018 A6 0.0041 1.8 0.9 0.09 0.0019 0.15 0.0012 0.0022 0 0.015 A7 0.0021 3 2.2 0.11 0.0023 0.05 0.0036 0.0016 0.054 0 A8 0.0022 2.1 1.3 0.08 0.002 0.14 0.0025 0.0011 0.016 0.014 A9 0.0019 3.2 0.8 0.08 0.0014 0.22 0.0028 0.002 0 0.048 A10 0.0015 2.4 1.1 0.05 0.0022 0.003 0.0034 0.0014 0.025 0.065 A11 0.0037 2.3 1.6 0.07 0.0018 0.003 0.0029 0.0017 0 0.047 A12 0.0036 2.9 2.3 0.03 0.0026 0.007 0.0036 0.0027 0.085 0

Steel grade Mn Addition Range
(0.5 * [Si] + [Al])
~ ([Si] + [Al]) Hardness (Hv) V _{100} (V _{111} + V _{112} ) Iron loss
W _15/50 Magnetic flux density
B ₅₀ Remarks A1 1.42 to 2.72 187 14 66 2.54 1.66 Comparative Example A2 1.94 to 3.59 220 18 73 2.41 1.64 Comparative Example A3 1.31 to 2.61 166 16 64 2.18 1.73 Honor A4 0.85 to 1.60 140 18 63 2.23 1.74 Honor A5 1.67-3.27 185 20 60 1.87 1.69 Honor A6 1.05 to 1.95 155 17 67 3.1 1.67 Comparative Example A7 1.55 to 3.05 179 17 61 1.91 1.7 Honor A8 1.19-2.24 157 17 63 2.1 1.73 Honor A9 1.82 ~ 3.42 211 15 69 2.38 1.64 Comparative Example A10 1.20 ~ 2.40 172 13 67 2.67 1.65 Comparative Example A11 1.15 ~ 2.30 159 16 59 2.14 1.72 Honor A12 1.46 ~ 2.91 173 19 64 2.01 1.7 Honor

Table 2 Hardness (Hv) is a value in the microhardness values (Vickers hardness), and the iron loss (W _15/50) is a rolling direction and rolling direction average loss in the vertical direction when the magnetic flux density in 1.5Tesla at 50Hz frequency organic (W / kg), and the magnetic flux density (B ₅₀ ) is a magnitude (Tesla) of magnetic flux density induced when a magnetic field of 5000 A / m is added.

As shown in Table 2, the steel types A3, A4, A5, A7, A8, A11, and A12 satisfying [Si], [Mn], [Al] V _{100} ≤ 20%, (V _{111} + V _{112} ) ≤ 65%. As a result, iron loss was low and magnetic flux density was high.

On the other hand, A1 satisfies the control range of Si, Al and Mn but does not satisfy the above formula (V _{111} + V _{112} ) was more than 65%. As a result, iron loss and magnetic flux density were inferior. A2 satisfies the composition formula (1), but Al is out of the control range. As a result, the hardness is 190 Hv or more, (V _{111} + V _{112} ) was more than 65%. As a result, iron loss and magnetic flux density were inferior. A6 and A9 are Mn and Mn, Al was this was not out of the management range satisfying the above formula A6 is hardness appeared above, but also the hardness was 190Hv A9 satisfied, A6 and A9 both (V _{111}, each + V _{112} ) was more than 65%. As a result, iron loss and magnetic flux density were inferior. A10 was Mn out of the control range and did not satisfy the above formula (V _{111} + V _{112} ) was more than 65%. As a result, iron loss and magnetic flux density were inferior.

[Example 2]

A steel ingot was prepared as shown in Table 3 through vacuum melting. At this time, the influence of the composition formula (1) and the annealing temperature of the hot-rolled sheet and the cold-rolled sheet on the hardness, texture and magnetism was examined. Each steel ingot was heated at 1150 ° C, hot rolled to a thickness of 2.1 mm, and then wound. The hot-rolled steel sheet taken up in the air and cooled was annealed at 800 to 1200 ° C for 130 seconds, pickled, cold-rolled to a thickness of 0.35 mm, and cold rolled sheet annealed at a temperature of 800 to 1200 ° C for 70 seconds. Hardness (W _15/50 ) and magnetic flux density (B ₅₀ ) were measured for each specimen by hardness and X-ray pole figure test. The results are shown in Table 4 below. .

Steel grade C Si Mn P S Al N Ti Sn Sb B1 0.0016 1.7 1.9 0.04 0.0013 0.01 0.0011 0.0015 0 0.03 B2 0.0019 1.3 1.4 0.01 0.0023 0.18 0.0037 0.0029 0.027 0.06 B3 0.0032 2.7 1.8 0.008 0.0021 0.007 0.0034 0.0037 0.015 0.04 B4 0.0037 3.4 2.3 0.05 0.0029 0.003 0.0022 0.0026 0 0.025 B5 0.0033 3.1 1.9 0.03 0.0024 0.11 0.0043 0.0021 0.033 0.012 B6 0.0034 2.5 1.1 0.09 0.0019 0.003 0.0019 0.0016 0.031 0.05 B7 0.0026 3.3 2.2 0.08 0.0044 0.15 0.0015 0.0009 0.07 0 B8 0.0021 2.1 1.6 0.12 0.0036 0.06 0.0026 0.0011 0.08 0 B9 0.002 2.2 1.4 0.07 0.0026 0.09 0.0031 0.0022 0.015 0.015 B10 0.0043 2.6 1.9 0.07 0.0033 0.07 0.0029 0.0026 0.029 0.049

Steel grade Mn Addition Range
(0.5 * [Si] +
[Al]) ~
([Si] + [Al]) Hot-rolled plate
Annealing temperature
(° C) Cold rolled plate
Annealing temperature
(° C) Hardness (Hv) V _{100} (V _{111} + V _{112} ) Iron loss
W _15/50 Magnetic flux
density
B ₅₀ Remarks B1 0.86 to 1.71 1060 820 176 16 68 2.77 1.67 Comparative Example B2 0.83 to 1.48 890 960 140 16 62 2.26 1.74 Honor B3 1.36 to 2.71 1130 980 156 19 64 2.09 1.71 Honor B4 1.70-3.40 950 1000 183 18 59 1.89 1.7 Honor B5 1.66 ~ 3.21 1100 970 177 16 65 2.01 1.71 Honor B6 1.25 to 2.50 1120 840 184 19 64 2.54 1.66 Comparative Example B7 1.80 to 3.45 830 830 209 13 71 2.47 1.65 Comparative Example B8 1.11-2.16 1170 920 191 14 67 2.55 1.67 Comparative Example B9 1.19 to 2.29 1060 940 155 18 63 2.11 1.73 Honor B10 1.37 to 2.67 1020 930 163 20 62 2.07 1.72 Honor

As shown in Table 3, the steel types B2 and B3 satisfying [Si], [Mn], [Al] and the composition formula (1) of the embodiment of the present invention and satisfying the annealing temperature of the hot- , B4, B5, B9 and B10 showed hardness of less than 190 Hv and V _{100} ≤ 20%, V _{111} V _{112} ) ≤ 65%. As a result, iron loss was low and magnetic flux density was high.

On the other hand, B1 satisfies the control range of [Si], [Mn], and [Al], but does not satisfy the above composition formula and annealing temperature of the cold rolled sheet is also lowered to 820 ° C. (V _{111} V _{112} ) was more than 65%, resulting in a loss of iron loss and magnetic flux density. B6 and B8 is [Si], [Mn], out of the management range and the composition formula (1), but satisfy the respective cold-rolled sheet annealing temperature and the hot-rolled sheet annealing temperature of the management range of _{[Al] (V {111}} + V _{112} ) was more than 65%, resulting in a loss of iron loss and magnetic flux density. B7 is [Si], [Mn], was management range and but satisfying the above composition formula (1) hardness lower both the hot-rolled sheet annealing temperature and the cold-rolled sheet annealing temperature above the management range of the [Al] Fig than 190Hv (V _{111} + V _{112} ) was more than 65%, resulting in a loss of iron loss and magnetic flux density.

The annealed sheet is shipped to the customer after the insulating coating treatment. The insulating coating may be treated with an organic, inorganic and organic composite coating, or may be treated with other insulating coatings. The customer can use the steel sheet after processing.

While the present invention has been described in connection with certain exemplary embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

Claims (9)

(Excluding 0%), Mn: 1.0 to 3.0%, P: 0.005 to 0.15%, N: 0.005% (excluding 0%), Si: 1.0 to 3.5% 0.001 to 0.005% of Ti, 0.005% or less of Ti (excluding 0%), Sn + Sb of 0.01 to 0.2%, and the balance of Fe and other inevitably added impurities,
The Si, Al, and Mn satisfy the following composition formula,
When the volume percentages of the {100}, {111}, and {112} texture of the 3 / 4t portion of the steel sheet thickness are V _{100}, V _{{111}, and} V _{112} , V _{100} %, (V _{111} + V _{112} ) ≤ 65%.
(0.5 * [Si] + [Al])? [Mn]? ([Si] + [Al]
[Si], [Al], and [Mn] in the above composition formula represent the weight percentages of Si, Al, and Mn, respectively. delete The method according to claim 1,
Wherein the steel sheet has a hardness of 190 Hv or less. The method according to claim 1 or 3,
Cu, Ni and Cr is added in an amount of 0.05 wt% or less, respectively. The method according to claim 1 or 3,
Zr, Mo and V are added in an amount of 0.01 wt% or less, respectively. (Excluding 0%), Mn: 1.0 to 3.0%, P: 0.005 to 0.15%, N: 0.005% (excluding 0%), Si: 1.0 to 3.5% 0.001 to 0.005% of Ti, 0.005% or less of Ti (excluding 0%), Sn + Sb of 0.01 to 0.2%, and the balance of Fe and other inevitably added impurities, Al, and Mn satisfy the following composition formula;
Reheating the slab to 1200 ° C or less;
Subjecting the reheated slab to hot rolling and annealing the hot-rolled sheet;
Wherein the annealing hot-rolled sheet is cold-rolled two times by cold-rolling or intermediate annealing, and the cold-rolled sheet annealing is performed at a temperature of more than 850 占 폚 and not more than 1000 占 폚 in an abnormal region of austenite and ferrite Wherein the method comprises the steps of:
(0.5 * [Si] + [Al])? [Mn]? ([Si] + [Al] The method according to claim 6,
The hot-
Wherein the temperature is in the range of 850 to 1150 占 폚. 8. The method according to claim 6 or 7,
Cu, Ni and Cr is added in an amount of 0.05 wt% or less, respectively. 8. The method according to claim 6 or 7,
Zr, Mo, and V are each added in an amount of 0.01 wt% or less.