KR101223113B1 - Method for manufacturing non-oriented electrical steel sheets having excellent magnetic properties and high permeability and non-oriented electrical steel sheets thereof - Google Patents

Abstract

The non-oriented electrical steel sheet of the present invention, in weight%, C: 0.005% or less, Si: 1.5 to 4.5%, Mn: 0.1 to 0.5%, P: 0.1% or less, sol.Al: 0.001% or less, S : 0.001% to 0.005%, Ti: 0.005% or less, N: 0.004% or less, Sb: 0.005% to 0.2%, hot rolled, cold rolled slab composed of the remaining Fe and other unavoidable impurities Cold-annealed annealing but cold-rolled annealing crack temperature is 850 ~ 1100 ℃, cold-annealed annealing up to 700 ℃ with heating rate of 12 ℃ / sec or higher and 700 ℃ or more with annealing rate of 10 ℃ / sec or higher It provides a method for producing a grain-oriented electrical steel sheet. Therefore, B50 ≥ 1.35 + 0.021 × V _{100} (V _{100} is the volume fraction of {100} tissue, B50 is 50Hz, magnetic flux density induced when applying 5000A / m magnetic field), {(L-direction permeability-C direction permeability) ) X 100 / (L direction permeability + C direction permeability)} ≥25, 10 ≤ {V _{100} / grain size (μm)} × 100 ≤ 15 Low iron loss high magnetic flux with excellent permeability in the rolling direction Density non-oriented electrical steel sheet can be produced.

Description

Low iron loss with excellent permeability in the rolling direction High magnetic flux density non-oriented electrical steel sheet and a method for manufacturing the same {Method for manufacturing non-oriented electrical steel sheets having excellent magnetic properties and high permeability and non-oriented electrical steel sheets

The present invention relates to a non-oriented electrical steel sheet used as a rotating device of a motor or a generator, an iron core of a transformer, etc. More specifically, the non-oriented electrical steel sheet having a low iron loss, high magnetic flux density and excellent permeability in the rolling direction and its manufacture It is about a method.

Non-oriented electrical steel sheet is mainly used as a material for iron cores in rotating machines of motors or generators and stationary devices such as small transformers. Recently, as the demand for efficient use of energy and the miniaturization of electric devices increases, the demand for improving the properties of non-oriented electrical steel sheets also increases.

The reason why the characteristics of non-oriented electrical steel sheet is important is that when magnetic is induced by adding electricity to iron core, the better magnetic properties of iron core material can reduce the energy lost by heat and induce a larger magnetic field with the same energy. And because the efficiency of the device can be increased. Good magnetic properties of electrical steel means low iron loss and high magnetic flux density. In particular, the non-oriented electrical steel sheet used for a stopper such as a motor for a split core or a small transformer is required to have a high permeability in the rolling direction as well as iron loss and magnetic flux density.

Among the magnetic properties of the non-oriented electrical steel sheet, in order to improve the iron loss, a method of adding Si, Al, etc., which are alloy elements having a large resistivity, is generally used to increase the electrical resistance. However, the addition of alloying elements reduces iron loss, but also decreases in magnetic flux density and permeability.

Therefore, in order to reduce iron loss and improve magnetic flux density and permeability characteristics, a technique of using a clean steel having an extremely low amount of impurities or adding a trace alloy element such as Ti and V has been used. However, all of these techniques cause an increase in manufacturing costs and do not solve the problem of deterioration of magnetism due to the formation of fine precipitates.

The present invention has been made to solve the problems in view of the prior art as described above, the object of the sol.Al is to contain only the minimum necessary amount for deoxidation of the steel and at the same time to add an appropriate amount of fine AlN precipitates And by suppressing the production of Al-based oxide, and by adding an appropriate amount of Sb to increase the texture structure advantageous to the magnetic to produce a non-oriented electrical steel sheet having a low iron loss, high magnetic flux density and excellent permeability in the rolling direction.

In addition, the present invention has a high volume fraction of {100} structure by controlling the heating rate at the time of cold rolling annealing according to the temperature section and imparting a low tension to the steel sheet at the time of cold rolling annealing, the size of the crystal grain is optimized, the rolling direction and rolling Another object of the present invention is to manufacture non-oriented electrical steel sheet having a large permeability variation in the vertical direction.

Low iron loss high magnetic flux density non-oriented electrical steel sheet having excellent permeability in the rolling direction of the present invention for solving the above problems is by weight, C: 0.005% or less, Si: 1.5 ~ 4.5%, Mn: 0.1 ~ 0.5 %, P: 0.1% or less, sol.Al: 0.001% or less, S: 0.001 ~ 0.005%, Ti: 0.005% or less, N: 0.004% or less, Sb: 0.005 ~ 0.2%, balance Fe and other unavoidably mixed Hot-rolled, cold-rolled, cold-rolled sheet annealing slabs composed of impurities, but the cracking temperature of the cold-rolled sheet annealing is 850 ~ 1100 ℃, annealing at a heating rate of 12 ℃ / sec or more up to 700 ℃ 700 annealing It is characterized by annealing at a heating rate of 10 ° C / sec or more up to a crack temperature from ℃.

The method for producing a non-oriented electrical steel sheet of the present invention is also characterized in that the tension applied to the steel sheet during cold-rolled sheet annealing is 0.5 kg / mm ² or less.

In the manufacturing method of the non-oriented electrical steel sheet of the present invention, the heating rate of the hot rolled sheet annealing is 2 ~ 20 ℃ / sec, when the temperature of the end of the heating table reaches 850 ~ 1100 ℃ lower the temperature within 30 seconds to crack the temperature of 800 ~ 1050 It is also characterized by annealing at a temperature of 10 to 120 seconds.

Non-oriented electrical steel sheet of the present invention for solving the above problems by weight, C: 0.005% or less, Si: 1.5 ~ 4.5%, Mn: 0.1 ~ 0.5%, P: 0.1% or less, sol.Al: 0.001% Or less, S: 0.001 to 0.005%, Ti: 0.005% or less, N: 0.004% or less, Sb: 0.005 to 0.2%, balance Fe and other inevitable impurities to be mixed, satisfying the following Equations 1 to 3 Characterized in that.

(Equation 1) B50 ≥ 1.35 + 0.021 x V _{100}

The V _{100} is the volume fraction (volume%) of the {100} tissue parallel to the rolling direction, and B50 is the magnetic flux density induced when a 50 Hz, 5000 A / m magnetic field is applied.

(Equation 2) {(L direction permeability-C direction permeability) × 100 / (L direction permeability + C direction permeability)} ≥25

The permeability of the L direction is the permeability of the rolling direction in the 1.5 Tesla magnetic field, and the permeability of the C direction is the permeability of the rolling vertical direction in the 1.5 Tesla magnetic field.

(Expression 3) 10 ≤ {V _{100} / grain size (㎛)} × 100 ≤ 15

According to the present invention, Al is added in the minimum amount necessary for deoxidation of steel in the steelmaking process and at the same time, an appropriate amount of S is added to suppress formation of fine AlN precipitates, and a small amount of segregation element Sb is added to favor the magnetic properties. The magnetic non-oriented electrical steel sheet can be manufactured by increasing the {100} tissue and reducing the {111} tissue which is a harmful aggregate.

In addition, by adjusting the heating rate to the cracking temperature during the annealing of the cold rolled sheet according to the temperature section, and by adjusting the tension conditions applied to the steel sheet during the cold rolled sheet annealing, the iron loss is low and the magnetic flux density is high without excessively increasing the amount of added elements. A non-oriented electrical steel sheet having excellent permeability in the rolling direction can be provided.

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

In the present invention, since Al is inevitably required for deoxidation of steel in the steelmaking process, Al is added to a minimum amount of 0.001% or less in the form of sol.Al so that fine AlN precipitates and Al-based It was intended to produce steel with high magnetic flux density by suppressing the formation of oxides and reducing the specific resistance as much as possible to increase the saturation magnetic flux density.

To this end, by adding S at 0.001 to 0.005% (10 to 50 ppm) in the components, it is possible to suppress the diffusion of N into the steel through the grain boundary as much as possible, and to form the fine precipitate AlN by adding Sb, the grain segregation element. Further suppression was made to increase the {100} structure, which is an advantageous structure for the magnetic properties, to reduce the iron loss, increase the magnetic flux density, and especially increase the permeability in the rolling direction.

In addition, in order to maximize the above effects, by controlling the heating rate during the annealing of the cold rolled sheet for each temperature and giving the tension of the steel sheet in the annealing furnace lower than 0.5kg / mm ² or less to increase the {100} structure advantageous to the magnetic properties It was.

Accordingly, when the volume fraction (volume%) of {100} tissue is V _{100} , the magnetic flux density (B50) induced at a magnetic field of 50 Hz and 5000 A / m is 1.35 + 0.021 × V _{100} or more, and the rolling direction Permeability deviation {(L direction permeability-C direction permeability) x 100 / (L direction permeability + C direction permeability)} of 1.5 Tesla in the rolling vertical direction is 25 or more and V _{100} / grain size (μm) x 100 The non-oriented electrical steel sheet having low iron loss, high magnetic flux density and excellent permeability in the rolling direction can be manufactured by having a value of 10 to 15.

According to the experiments of the present inventors, when the conditions of B50 ≥ 1.35 + 0.021 x V _{100} are satisfied, B50 and V _{100} have high values, and in particular, the permeability of the rolling direction is improved, so that the rolling direction and V _{100} / grain size measured in non-oriented electrical steel sheet with a permeability deviation {(L-direction permeability-C direction permeability) × 100 / (L-direction permeability + C-direction permeability)} of rolling vertical direction increased to 25 or more It was investigated that very low iron loss is ensured under the condition that (μm)} × 100 satisfies the range of 10-15.

First, look at the reasons for limiting the components of the present invention.

When a large amount of C is added, the austenite region is expanded, the phase transformation period is increased, and the iron loss is deteriorated by suppressing the grain growth of ferrite during annealing. In addition, it should be contained less than 0.005% because the iron loss is increased by self-aging when processed from the final product to the electric product.

S is added at least 0.001% or more to suppress the formation of nitrides through grain penetration of N. However, if excessively added, sulfides such as MnS and CuS, which are harmful to magnetic properties, are formed, so the amount is limited to 0.005% or less. Therefore, the content of S is preferably 0.001 to 0.005% (10 to 50ppm).

Mn increases the specific resistance together with Si and Al to lower the iron loss. In addition, it is added to grow the grain and develop the texture, and when the amount is too small, the iron loss improving effect is insignificant and the texture becomes bad, so 0.1% or more is added. However, Mn combines with S to form a fine MnS precipitate, and if it exceeds 0.5%, iron loss is increased due to the MnS precipitate. Therefore, Mn is to be contained in 0.1 ~ 0.5%.

sol.Al is inevitably added for deoxidation of steel in the steelmaking process. Since sol.Al decreases the magnetic flux density by decreasing the saturation magnetic flux density in proportion to the addition amount, inhibits grain growth by forming fine AlN, and especially causes the permeability to be reduced, the addition amount contains only the minimum amount necessary for deoxidation of steel. It is desirable to limit the amount to 0.001% or less.

Since N is an element harmful to magnetism, such as forming carbonitrides such as AlN and inhibiting grain growth, it is preferable to contain N less than 0.004% by weight or less.

Ti forms fine carbonitrides to suppress grain growth, and as the amount of Ti is added, the increased carbonitrides result in inferior texture, resulting in poor magnetic properties. Therefore, the present invention is preferably limited to 0.005% or less.

Si is added because it increases the specific resistance of the steel and lowers the vortex loss in iron loss, and it is difficult to obtain low iron loss characteristics at 1.5% or less and it is difficult to improve the permeability in the rolling direction. If Si is added in excess of 4.5%, the cold rolling property is lowered and plate breaking occurs, so the Si content is preferably limited to 1.5 to 4.5%.

P is added to increase specific resistance, lower iron loss, and segregation at grain boundaries, thereby suppressing formation of harmful tissues and forming advantageous textures. However, P is preferably limited to 0.1% or less since cold rolling becomes worse when added. Do.

Sb segregates at grain boundaries to suppress the diffusion of nitrogen through the grain boundaries, suppresses {111} tissues that are harmful to magnetism, and is added to increase magnetic properties by increasing {100} tissues that are beneficial to magnetism. If Sb is added below 0.005%, the above effect is difficult to obtain, and when Sb is added above 0.2%, Sb content is limited to 0.005 ~ 0.2% because it suppresses grain growth, decreases magnetism and worsens rolling property. .

In addition to the above compositions, the remainder is composed of Fe and other inevitable impurities.

Hereinafter, the manufacturing method of this invention is demonstrated.

Steel slabs having the above composition are made of molten steel in steelmaking and then solidified in a continuous casting process, charged into a hot preheating furnace, and reheated to a temperature of 1200 ° C. or lower. If the slab reheating temperature is excessively high, the slag reheating temperature is limited to 1200 ℃ or less because the harmful particles such as AlN and MnS present in the slab are re-employed and then finely precipitated during hot rolling to inhibit grain growth and decrease magnetism. do.

The slabs heated as above are subjected to hot rolling. Hot rolling may be performed by rough finishing and rough rolling. Finishing rolling in finishing rolling during hot rolling is finished in ferrite phase, and final rolling reduction is preferably 20% or less for plate shape correction.

The hot rolled sheet produced as described above is wound up at 700 ° C. or lower and cooled in air. The coiled and cooled hot rolled sheet is pickled after performing the hot rolled sheet annealing as necessary. Hot-rolled sheet annealing is carried out when necessary to improve magnetic properties.

In the case of performing hot-rolled sheet annealing, the heating rate is set to 2 to 20 ° C / sec, and when the end temperature of the heating table reaches 850 to 1100 ° C, the temperature is lowered within 30 seconds to be annealed at a crack temperature of 800 to 1050 ° C for 10 to 120 seconds. do.

On the premise that the overall process time is constant, it is difficult to obtain the desired grains in the product when the heating rate is slower than 2 ° C / sec during hot-rolled sheet annealing, and it is difficult to obtain the desired grains because the grains grow excessively faster than 20 ° C / sec. This is because, for a certain process time, the faster the heating rate is shorter the time to reach the target temperature, thereby increasing the time for the grain to grow.

The end temperature of heating zone of hot rolled plate is 850 ~ 1100 ℃ because the grain growth is insufficient when the end temperature of heating zone is lower than 850 ℃, and when it exceeds 1100 ℃, grains grow excessively and surface defect of plate It is because it is excessive.

The cracking temperature of the hot-rolled sheet annealing is 800 ~ 1050 ℃, because the grain growth is difficult when the crack temperature is less than 800 ℃, when the grain exceeds 1050 ℃ excessive grain growth.

When heating the hot rolled sheet, the cooling time from the end temperature of the heating table to the cracking temperature should be within 30 seconds. This is because when the cooling time exceeds 30 seconds, grains grow excessively.

In addition, the holding time at the cracking temperature during the annealing of the hot rolled sheet is 10 seconds or more and 2 minutes or less. If it is kept less than 10 seconds, the grain growth is insufficient and sufficient homogeneous annealing is not performed, and if it is maintained for more than 2 minutes, the grain time is excessively grown, so the cracking time is 10 seconds or more and 2 minutes or less.

Subsequently, the hot rolled sheet is annealed and cold rolled. Cold rolling is finally rolled to a thickness of 0.10mm to 0.70mm to produce a cold rolled plate. Cold rolling may be performed by one cold rolling or by two or more cold rolling, if necessary, such as primary cold rolling and secondary cold rolling after intermediate annealing, if necessary. Final rolling reduction rate of cold rolling can be 50-95%.

The cold rolled cold rolled sheet is subjected to cold rolled sheet annealing. In the present invention, the control of the cold roll annealing conditions is important. In the present invention, by controlling the heating rate during the annealing of the cold rolled sheet by the temperature and by applying a low tension of 0.5kg / mm ² or less to the steel sheet in the annealing furnace, the iron loss satisfying the following three conditions is low and the magnetic flux density is high while in the rolling direction It is characterized by manufacturing non-oriented electrical steel sheet having excellent permeability.

1) B50 ≥ 1.35 + 0.021 × V _{100}

The V _{100} is a volume fraction (volume%) of the {100} tissue, which is advantageous for magnetic properties, and the B50 is a magnetic flux density induced when a 50 Hz, 5000 A / m magnetic field is applied.

2) {(L direction permeability-C direction permeability) × 100 / (L direction permeability + C direction permeability)} ≥ 25

The permeability of the L direction is the permeability of the rolling direction in the 1.5 Tesla magnetic field, and the permeability of the C direction is the permeability of the rolling vertical direction in the 1.5 Tesla magnetic field.

3) 10 ≤ {V _{100} / grain size (μm)} × 100 ≤ 15

If {V _{100} / grain size (μm)} × 100 is less than 10, there is a problem that the iron loss is high and the permeability is also lowered. If it exceeds 15, the magnetic flux density and the rolling direction permeability are not high, so V _{100} / Grain size (µm) x 100 should be 10-15.

In the cold-rolled sheet annealing process, the cracking temperature is set at 850-1100 ° C. The cold rolled sheet annealing temperature is less than 850 ℃ grain growth is insufficient to increase the {111} structure, which is harmful to magnetism, and at temperatures above 1100 ℃ crystal grains grow excessively may adversely affect the magnetic to be.

In the cold-rolled sheet annealing process, the annealing is performed at a heating rate of 12 ° C./sec or higher up to 700 ° C. and annealing at a temperature of 10 ° C./sec or more from 700 ° C. to a cracking temperature. If the temperature rise rate up to 700 ℃ is less than 12 ℃ / sec, the formation of {100} aggregates is suppressed when recrystallization due to the decrease of strain energy, which may have a detrimental effect on magnetism. If less than 10 ℃ / sec grain growth is insufficient to increase the {111} aggregate structure, which adversely affects the magnetism.

When the cold rolled sheet is annealed, the tension applied to the steel sheet is 0.5 kg / mm ² or less. This is because if the tension is more than 0.5kg / mm ² during cold annealing, the magnetism may become thermally deteriorated due to residual stress after annealing.

After performing cold roll annealing as described above, the annealing plate is shipped to the customer. At this time, it can be shipped after the insulation coating treatment. The insulating coating may be treated with an organic, inorganic or organic-inorganic composite coating, or may be treated with other insulating coating. The customer can use the steel plate as it is after processing.

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

The steel slab, as shown in Table 1, was heated at 1180 ° C., hot rolled to a thickness of 2.3 mm, and wound up. The hot rolled steel sheet wound and cooled in air was annealed under the conditions of Table 2, pickled, and cold rolled to a thickness of 0.35 mm. Subsequently, after performing cold roll annealing under the conditions of Table 2, magnetic properties, rolling permeability, permeability variation, grain size, and volume fraction of {100} tissue were investigated and the results are shown in Table 2.

Name C * Si S * P Mn Sol.Al N Ti * Sb Inventive Steel A 32 3.31 11 0.03 0.19 0.0008 24 17 0.03 Inventive Steel B 22 3.19 15 0.03 0.25 0.0007 13 8 0.02 Invention Steel C 19 3.08 26 0.05 0.41 0.0010 21 22 0.05 Inventive Steel D 23 3.19 13 0.06 0.32 0.0009 16 10 0.08 Inventive Steel E 28 3.02 30 0.02 0.39 0.0007 20 24 0.09 Comparative Steel A 22 3.38 18 0.02 0.26 0.0019 27 19 0.01 Comparative Steel B 29 3.12 27 0.05 0.31 0.0017 41 9 0.03 Comparative Steel C 35 3.09 7 0.07 0.25 0.0009 30 15 0.06

1) In the above components, C, S, Ti is in ppm unit, others are in weight percent unit.

division Name Hot Rolled Annealing Condition Cold rolled plate
Annealing Condition Iron loss
(W15 / 50) Magnetic flux
density
(B50) 1.35+
0.021 × V _{100} Rolling direction
Investment ratio
(U1.5) Investment ratio
Deviation
(%) {V _{100} /
Crystal grain
size
(μm)}
* 100 crack
Temperature
(℃) crack
time
(s) Up to 700 ℃
Heating speed
(° C / s) 700 ℃ or higher
Heating speed
(° C / s) crack
Temperature
(℃) tension
(kg /
mm ² ) Inventory 1 Inventive Steel A 920 30 15 12 1080 0.3 1.99 1.712 1.709 1815 34 10.1 Inventory 2 Inventive Steel B 1050 50 22 11 1020 0.5 2.02 1.710 1.705 1789 31 11.7 Invention 3 Inventive Steel B 1000 100 20 13 1040 0.3 1.92 1.701 1.697 1756 28 10.9 Comparison 1 Inventive Steel B 1040 90 14 15 830 0.4 2.54 1.671 1.678 1165 19 17.7 Invention 4 Invention Steel C 860 60 16 16 990 0.5 1.85 1.715 1.713 1855 37 14.2 Invention Article 5 Inventive Steel D 930 80 15 12 980 0.5 1.91 1.707 1.707 1798 31 14.7 Comparative material 2 Inventive Steel D 930 100 9 11 960 0.5 2.29 1.681 1.684 1216 24 15.1 Inventions 6 Inventive Steel E 1020 40 19 18 1000 0.3 1.95 1.716 1.709 1834 35 13.3 Invention 7 Inventive Steel E 990 110 21 11 960 0.4 1.89 1.711 1.703 1811 33 14.9 Comparative material 3 Inventive Steel E 1060 80 15 8 940 0.5 2.38 1.677 1.682 1196 22 16.6 Comparison 4 Comparative Steel A 820 100 20 15 990 0.3 2.49 1.682 1.690 1248 21 13.6 Comparative material 5 Comparative Steel B 900 60 16 17 1110 0.5 2.34 1.688 1.699 1311 23 8.9 Comparative material 6 Comparative Steel C 960 70 18 18 840 0.5 2.45 1.683 1.694 1277 21 19.2

2) _Iron loss (W _15/50 ) is the average loss (W / kg) in the rolling direction and the rolling vertical direction when the magnetic flux density of 1.5 Tesla is induced at 50 Hz.

3) The magnetic flux density (B ₅₀ ) is the magnitude of the magnetic flux density (Tesla) induced when a magnetic field of 5000 A / m is added.

4) Permeability (U1.5) is the permeability derived from magnetic flux density at 1.5 Tesla.

5) V _{100} is the volume fraction ({%}) of {100} tissue parallel to the rolling direction of the 3 / 4t section of the specimen as measured by X-ray pole figure test, measured at a tolerance of 15 °. .

As shown in Table 2, Inventions 1 to 7 produced by the production conditions of the present invention using the invention steel (A ~ E) satisfying the component range of the present invention showed a low iron loss and a high magnetic flux density. Invention materials 1 to 7 have magnetic flux densities (B50) of 1.35 + 0.021 × V _{100} or more, and a permeability variation in 1.5 Tesla in the rolling direction and the rolling vertical direction induced in a magnetic field of 5000 A / m {(L Permeability- C-direction permeability) x 100 / (L-direction permeability + C-direction permeability)} is also 25 or more, it can be seen that {V _{100} / grain size (μm)} × 100 has a value of 10-15.

Comparative material 1 can be seen that even in the invention steel, the cold temperature of the cold-rolled sheet annealing is low due to low crystal grain growth, the iron loss is high and the magnetic flux density is lower than 1.35 + 0.021 × V _{100} . In addition, the comparative material 1 is {V _{100} / grain size (㎛)} × 100 also out of the range (10 ~ 15) of the present invention, it can be seen that the permeability variation in the rolling direction and the rolling vertical direction is also low.

In comparison steel 2, even though the invention steel is cold-annealed, the heating rate up to 700 ℃ is 9 ℃ / s, which reduces the aggregate structure favorable for magnetism, resulting in high iron loss and lower magnetic flux density than 1.35 + 0.021 × V _{100}. Can be. In addition, the variation in permeability between the rolling direction and the rolling vertical direction is also low, and it can be seen that {V _{100} / grain size (μm)} × 100 is also outside the scope of the present invention (10 to 15).

Comparative material 3 is also an invention steel, but the heating rate from 700 ℃ or more to the cracking temperature is 8 ℃ / s when cold rolled sheet is annealed, so that grain growth does not occur sufficiently and the harmful structure is increased, and the iron loss and magnetic flux density are increased. You can see that you are out of range.

Comparative material 4 has high sol.Al and low cracking temperature in hot rolled sheet annealing, high iron loss, low magnetic flux density, and low permeability in rolling direction and low permeability in rolling direction and rolling vertical direction.

In Comparative Material 5, since Sol.Al and N are higher than the range of the present invention, many AlN precipitates harmful to magnetism are generated. As a result, iron loss is high, but the permeability in the rolling direction is insufficient, and the permeability variation is low. In addition, the crystal grains were coarsened due to the high cracking temperature during cold annealing. As a result, the value of {(V _{100} / size (μm)} × 100) was also smaller than the range (10 to 15) of the present invention. have.

Comparative material 6 has too little S content and low cold-rolled sheet annealing temperature, so that the grain growth is insufficient, so that the iron loss is high, the energy loss is high, and the permeability of the rolling direction is also worsened.

By weight, C: 0.0021%, Si: 3.21%, Mn: 0.36%, P: 0.035%, S: 0.0026%, sol.Al: 0.0007%, N: 0.0025%, Ti: 0.0021%, Sb: 0.11% After reheating the slab composed of the remaining Fe and other unavoidable impurities to 1130 ° C., the finishing rolling temperature of the filament rolling during hot rolling was 880 ° C. to produce a 2.0 mm thick hot rolled steel sheet. The hot rolled steel sheet was wound at 630 ° C. and then air cooled, and the hot rolled steel sheet was annealed. The hot zone finish temperature of the hot-rolled sheet annealing was 1040 ° C., the crack zone temperature was 1020 ° C., and the crack zone holding time was 60 seconds. The annealed hot rolled sheet was pickled, cold rolled to a thickness of 0.35 mm, and annealed the cold rolled sheet at 1050 ° C. In the cold-rolled sheet annealing, annealing was performed at a heating rate of 15 ° C./sec up to 700 ° C., and annealing at 14 ° C./sec or more at 700 ° C. or higher. At this time, the tension at the time of annealing was set to two conditions of 0.5kg / mm ² and 0.8kg / mm ² .

As a result of measuring the magnetism, texture, grain size, etc. of the two annealing plates, the iron loss (W15 / 50) was 1.88 (W / Kg) and the magnetic flux density (B50) when the cold rolled sheet annealing tension was 0.5kg / mm ² . Is 1.714 (Tesla), permeability (U1.5) is 1789, and permeability deviation is 33 (%), which is excellent in iron loss, magnetic flux density and rolling permeability. Also, 1.35 + 0.021 × V _{100} is 1.711, and the magnetic flux density satisfies the conditions of the present invention (B50 ≥ 1.35 + 0.021 × V _{100} ), and {V _{100} / grain size (μm)} × 100 It is also within the scope of the present invention as 12.3.

On the other hand, when the tension is 0.8 kg / mm ² , the iron loss (W15 / 50) is 2.24 (W / Kg), the magnetic flux density (B50) is 1.681 (Tesla), the permeability (U1.5) is 1294, and the permeability deviation. Was 23 (%), high iron loss, low magnetic flux density, and low permeability and rolling permeability. In addition, {V _{100} / grain size (µm)} × 100 was 12.1, which satisfied the present invention (10 to 15), but 1.35 + 0.021 × V _{100} was 1.697, which is 1.681 ( Higher than Tesla) did not satisfy the conditions of the present invention.

By weight, C: 0.0019%, Si: 3.1%, Mn: 0.14%, P: 0.06%, S: 0.0034%, sol.Al: 0.0010%, N: 0.0025%, Ti: 0.0029%, Sb: 0.09% After reheating the slab composed of the remaining Fe and other unavoidable impurities to 1170 ° C., the finishing rolling temperature of the filament rolling during hot rolling was 880 ° C. to produce a 2.0 mm thick hot rolled steel sheet. The hot rolled steel sheet was wound at 660 ° C. and then air cooled, and the hot rolled sheet was annealed. The hot zone finish temperature of the hot rolled annealing plate was 990 ° C, the crack zone temperature was 960 ° C, and the crack zone holding time was 100 seconds. The annealed hot rolled sheet was pickled, cold rolled to a thickness of 0.35 mm, and annealed the cold rolled sheet at 960 ° C. In the cold-rolled sheet annealing, annealing was performed at a heating rate of 21 ° C./sec up to 700 ° C., and annealing at a heating rate of 17 ° C./sec at 700 ° C. to 960 ° C. The tension during the cold rolled sheet annealing was 0.2 kg / mm ² . As a result of measuring the magnetism, texture, and grain size of the annealing plate, iron loss (W15 / 50) is 1.96 (W / Kg), magnetic flux density (B50) is 1.709 (Tesla), and magnetic permeability (U1.5) is 1812. The variation in permeability was 31%. 1.35 + 0.021 × V _{100} is 1.705, and the magnetic flux density satisfies the conditions of the present invention (B50 ≥ 1.35 + 0.021 × V _{100} ), and the {V _{100} / grain size (μm)} × 100 Case 14.7 also satisfied the scope of the present invention.

Claims (7)

In weight%, C: 0.005% or less (excluding 0), Si: 1.5 to 4.5%, Mn: 0.1 to 0.5%, P: 0.1% or less (excluding 0), sol.Al: 0.001% or less (excluding 0), S: Slab containing 0.001 to 0.005%, Ti: 0.005% or less (excluding 0), N: 0.004% or less (excluding 0), Sb: 0.005 to 0.2% and consisting of the balance Fe and other unavoidable impurities Hot-rolled, cold-rolled, cold-annealed annealing, but the cold temperature of the cold-annealed sheet annealing is 850 ~ 1100 ℃, annealing at 700 ℃ annealing at a heating rate of 12 ℃ / sec or more and cracking temperature at 700 ℃ or more The low iron loss high magnetic flux density non-oriented electrical steel sheet excellent in the permeability of the rolling direction to be annealed at a heating rate of 10 ℃ / sec or more. The method according to claim 1,
A method for producing a low iron loss high magnetic flux density non-oriented electrical steel sheet having excellent permeability in the rolling direction in which the tension applied to the steel sheet during cold annealing is 0.5 kg / mm ² or less. The method according to claim 1,
A method for producing a low iron loss high magnetic flux density non-oriented electrical steel sheet having excellent permeability in the rolling direction in which the hot rolled sheet is subjected to annealing after hot rolling before cold rolling. The method according to claim 3,
When the hot rolled sheet is annealed, the heating rate is 2 ~ 20 ℃ / sec, and when the end temperature of the heating table reaches 850 ~ 1100 ℃, the temperature is lowered within 30 seconds. Low iron loss high magnetic flux density non-oriented electrical steel sheet with excellent permeability. In weight%, C: 0.005% or less (excluding 0), Si: 1.5 to 4.5%, Mn: 0.1 to 0.5%, P: 0.1% or less (excluding 0), sol.Al: 0.001% or less (excluding 0), S: 0.001 to 0.005%, Ti: 0.005% or less (excluding 0), N: 0.004% or less (excluding 0), Sb: 0.005 to 0.2%, remainder Fe and other unavoidably mixed impurities, Low iron loss high magnetic flux density non-oriented electrical steel sheet with excellent permeability in the rolling direction that satisfies 1.
(Equation 1) B50 ≥ 1.35 + 0.021 x V _{100}
The V _{100} is the volume fraction (volume%) of the {100} tissue parallel to the rolling direction, and B50 is the magnetic flux density induced when a 50 Hz, 5000 A / m magnetic field is applied. The method according to claim 5,
Low iron loss high magnetic flux density non-oriented electrical steel sheet excellent in permeability in the rolling direction that satisfies Equation 2 below.
(Equation 2) {(L direction permeability-C direction permeability) × 100 / (L direction permeability + C direction permeability)} ≥25
The permeability of the L direction is the permeability of the rolling direction in the 1.5 Tesla magnetic field, and the permeability of the C direction is the permeability of the rolling vertical direction in the 1.5 Tesla magnetic field. The method according to claim 5 or 6,
A low iron loss high magnetic flux density non-oriented electrical steel sheet having excellent permeability in the rolling direction that satisfies Equation 3 below.
(Expression 3) 10 ≤ {V _{100} / grain size (㎛)} × 100 ≤ 15
V _{100} is the volume fraction (volume%) of the {100} structure parallel to the rolling direction.