JP2004300535A - High strength nonoriented silicon steel sheet having excellent magnetic property, and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reconcile satisfactory magnetic properties and high strength in a nonoriented silicon steel sheet, and to industrially stably produce the same. <P>SOLUTION: The nonoriented silicon steel sheet has a componential composition comprising ≤0.02% C, ≤4.5% Si, ≤3.0% Mn, ≤3.0% Al, ≤0.50% P, 0.5 to 5.0% Ni and 0.2 to 4.0% Cu, and the balance Fe with inevitable impurities, and in which tensile strength is controlled to be CTS (MPa) shown by the following formula or larger: CTS=5600[%C]+87[%Si]+15[%Mn]+70[%Al]+430[%P]+37[%Ni]+22d<SP>-1/2</SP>+230; wherein, d is the average grain size (mm) of the crystal grains. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３８】
【表２】

【００３９】
本発明による鋼板Ｎｏ．７〜１３は、ベース組成を有する比較例である鋼板Ｎｏ．１とほぼ同等の優れた磁気特性を有しつつ、大幅な高強度が得られている。さらに、従来の高強度電磁鋼板である鋼板Ｎｏ．１４〜１６と比較しても、大幅な低鉄損あるいは高磁束密度性を有し、強度−磁気特性バランスに優れている。
【００４０】
実施例２
表１に示した比較鋼Ｃおよび発明鋼Ｊを、熱間圧延により板厚２．０ｍｍとし、ついで１０００℃で３００ｓの熱延板焼鈍を施した後、酸洗並びに仕上げ板厚０．３５ｍｍの冷間圧延を行った。さらに、最高到達温度９５０℃にて３０ｓ均熱保持する仕上げ焼鈍を施し、９００℃〜４００℃の温度域での冷却速度を表３に示す種々の条件に変化させて冷却した。その後、絶縁被膜を塗布焼付けして焼鈍板とした。得られた焼鈍板に時効のため５５０℃で５ｈの熱処理を施して製品板とした。かくして得られた製品板について、鉄損特性および機械特性を評価した。なお、製品板での成分組成はスラブ段階とはぼ同様であった。その結果を表３、そして図１および２に示す。
【００４１】
【表３】

【００４２】
鋼Ｃは、鋼板Ｎｏ．１８および１９に示すように、１０℃／ｓ以上の比較的速い冷却速度の場合には優れた磁気特性と高強度を示すものの、１０℃／ｓ以下の条件では鉄損が劣化し、強度も低下する傾向にある。それに対して、Ｃｕとともに適量のＮｉを添加した発明鋼Ｊは、鋼板Ｎｏ．２２〜２４に示すように、幅広い冷却速度条件で安定して優れた磁気特性と高強度を両立することが可能であった。
【００４３】
実施例３
表４に示す組成を有する残部が鉄および不可避不純物からなる鋼を、熱間圧延により板厚２．０ｍｍとし、ついで無焼鈍または表５に示す温度で３００ｓの熱延板焼鈍を施した後、酸洗ならびに所定厚さまでの冷間圧延を行った。さらに、表５の温度で３０ｓ均熱保持の仕上げ焼鈍を施し、９００℃〜４００℃の温度域での冷却速度を６℃／ｓの条件で冷却した。その後、絶縁被膜を塗布焼付けして焼鈍板とした。得られた焼鈍板に時効のため表５に示す温度で１０ｈの時効処理を施して製品板とした。かくして得られた製品板について、鉄損特性および機械特性を評価した。その結果を表５に併記する。なお、製品板での成分組成はスラブ段階とほぼ同様であった。表５から、いずれの試料もそれぞれの鋼板グレードにおいて、優れた磁気特性と非常に高い強度特性を有していることがわかる。
【００４４】
【表４】

【００４５】
【表５】

【００４６】
【発明の効果】
以上のように本発明によれば、磁気特性に優れ、しかも高い強度を有する電磁鋼板を安定して提供することできる。
【図面の簡単な説明】
【図１】時効処理後の鉄損に及ぼす仕上げ焼鈍冷却速度の影響を示す図である。
【図２】時効処理後の引張強さに及ぼす仕上げ焼鈍冷却速度の影響を示す図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a non-oriented electrical steel sheet, particularly a typical example of a rotor of a high-speed rotation motor, suitable for parts subjected to large stress, high-strength and non-oriented electrical steel sheet having low iron loss characteristics and It relates to the manufacturing method.
[0002]
[Prior art]
In recent years, with the development of motor drive systems, it has become possible to control the frequency of a drive power supply, and the number of motors that perform high-speed rotation at variable speed operation or commercial frequency is increasing. Such a motor that rotates at high speed requires a rotor that can withstand high-speed rotation. That is, since the centrifugal force acting on the rotating body increases in proportion to the radius of rotation and in proportion to the square of the rotation speed, the stress acting on the rotor may exceed 600 MPa in a medium-sized or large-sized high-speed motor. Therefore, in such a high-speed rotation motor, the strength of the rotor needs to be high.
[0003]
In addition, in a magnet embedded DC inverter control motor in which permanent magnets are embedded in the rotor, which has been increased from the viewpoint of improving motor efficiency in recent years, the magnets tend to fly out of the rotor by centrifugal force. A large force is applied to the used electromagnetic steel sheet. For this reason, high strength is required for electrical steel sheets used for motors, especially rotors.
[0004]
Rotating devices such as motors and generators utilize electromagnetic phenomena, and therefore it is desirable that the material thereof has magnetic properties, that is, low iron loss and high magnetic flux density. Normally, the rotor core is used by laminating non-oriented electrical steel sheets that have been stamped out by stamping.If the rotor material cannot satisfy the above-mentioned mechanical strength in a high-speed rotation motor, a higher-strength cast steel rotor or the like must be used. It is the present situation that does not get. However, since the cast rotor is an integral body, the eddy current loss due to high-frequency magnetic flux called ripple loss acting on the rotor is larger than that of a rotor having laminated electromagnetic steel sheets, which is a factor that lowers the motor efficiency. Accordingly, a magnetic steel sheet having excellent magnetic properties and high strength has been demanded as a material for a rotor.
[0005]
In terms of metallurgy, three methods of solid solution strengthening, precipitation strengthening and grain refinement are known as means for increasing strength, and examples of application to electromagnetic steel sheets are also seen. For example, as a method using solid solution strengthening, Patent Literature 1 discloses a method of increasing the Si content to 3.5 to 7.0% and adding an element having a large solid solution strengthening ability. I have. Patent Document 2 discloses that the recrystallized grains are produced by setting the Si content to 2.0 to 3.5%, increasing the content of Ni or both Ni and Mn, and performing low-temperature annealing at 650 to 850 ° C. A method for controlling the diameter is disclosed. Further, as a method utilizing precipitation strengthening, Patent Document 3 discloses a method in which the Si content is 2.0 to 4.0% and fine carbides and nitrides of Nb, Zr, Ti, and V are precipitated. Have been.
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. Sho 60-238421 [Patent Document 2]
JP 62-256917 A [Patent Document 3]
JP-A-6-330255
[Problems to be solved by the invention]
By these methods, an electromagnetic steel sheet having a certain high strength can be obtained. However, steel having a large amount of Si as described in Patent Literature 1 has a disadvantage that the cold rollability is remarkably reduced and stable industrial production becomes difficult. Further, the steel sheet obtained by this technique is magnetic flux density _{B 50} has a problem that deteriorates significantly and 1.56～1.60T.
[0008]
According to the method disclosed in Patent Document 2, it is necessary to suppress the growth of recrystallized grains by low-temperature annealing in order to increase the mechanical strength. Therefore, there is a problem that the magnetic properties, particularly the iron loss at several hundred Hz from a relatively low commercial frequency, are reduced. was there. Therefore, it cannot be used for a stator member in which iron loss in these frequency ranges is important, so that the yield at the time of punching a motor has to be significantly reduced. That is, when punching a stator and a rotor, an annular stator is usually punched from the same sheet of steel, while the rotor is punched from the hollow portion to reduce waste. In the second method, both need to be punched from separate steel plates, and the yield decreases.
[0009]
On the other hand, the method described in Patent Literature 3 has a problem that the carbon loss is inferior because the carbon and the nitride themselves act as barriers for domain wall movement, and the carbon and the nitride hinder the crystal grain growth of the magnetic steel sheet.
[0010]
As described above, none of the conventional methods is satisfactory from the viewpoint of achieving both high strength and low iron loss in magnetic steel sheets that can be stably industrially produced.
[0011]
An object of the present invention is to propose a non-oriented electrical steel sheet having both good magnetic properties and high strength, and a manufacturing method capable of industrially stably producing this steel sheet.
[0012]
[Means for Solving the Problems]
The present inventors have conducted various studies focusing on the age hardening phenomenon of steel containing Cu in order to solve the above problems, and as a result, have established means for achieving both good iron loss and high strength. I came to. That is, contrary to the conventional knowledge that precipitates in steel contribute to high strength and suppress domain wall movement and deteriorate at the same time, by adding an appropriate amount of Cu to steel and performing aging treatment, It is possible to precipitate the following ultra-fine Cu, and the ultra-fine precipitate thus obtained is very effective for increasing the strength, but hardly deteriorates iron loss (history loss). Was newly found. Furthermore, with respect to this Cu precipitation, when Cu and Ni are added in combination, the precipitation caused by the heat history in the manufacturing process of the steel sheet is greatly reduced, so that high strength and low iron loss can be stably obtained even under a wide range of annealing conditions. This has been newly found, and the present invention has been completed.
[0013]
The gist configuration of the present invention is as follows.
(1) In mass%,
C: 0.02% or less,
Si: 4.5% or less,
Mn: 3.0% or less,
Al: 3.0% or less,
P: 0.50% or less,
Ni: contains 0.5% or more and 5.0% or less and Cu: 0.2% or more and 4.0% or less, has a component composition of balance Fe and inevitable impurities, and has a tensile strength represented by the following formula. A high strength non-oriented electrical steel sheet having excellent magnetic properties, characterized by having a CTS (MPa) or higher.
CTS = 5600 [% C] +87 [% Si] +15 [% Mn] +70 [% Al] +430 [% P] +37 [% Ni] + 22d− ^{1 / 2} + 230
Here, d: average grain size of crystal grains (mm)
[0014]
(2) In the above (1), one or more selected from Zr, V, Sb, Sn, Ge, B, Ca, a rare earth element, and Co are further used as a component composition.
0.1 to 3.0% for each of Zr and V;
0.002 to 0.5% for Sb, Sn and Ge,
0.001 to 0.01% for B, Ca and rare earth elements, and 0.2 to 5.0% for Co
A high-strength non-oriented electrical steel sheet with excellent magnetic properties characterized by containing
[0015]
(3) In mass%,
C: 0.02% or less,
Si: 4.5% or less,
Mn: 3.0% or less,
Al: 3.0% or less,
P: 0.50% or less,
After hot rolling is performed on a steel slab containing Ni: 0.5% or more and 5.0% or less and Cu: 0.2% or more and 4.0% or less, cold rolling or warm rolling is performed. After the final sheet thickness, the final reaching temperature is 650 to 1150 ° C and the cooling rate in the temperature range of 900 ° C to 400 ° C is 1 ° C / s or more. A method for producing a high-strength non-oriented electrical steel sheet having excellent magnetic properties, characterized by aging at a temperature of
[0016]
(4) In mass%,
C: 0.02% or less,
Si: 4.5% or less,
Mn: 3.0% or less,
Al: 3.0% or less,
P: 0.50% or less,
Ni: contains 0.5% or more and 5.0% or less and Cu: 0.2% or more and 4.0% or less, and is further selected from Zr, V, Sb, Sn, Ge, B, Ca, rare earth elements, and Co. One or two or more
0.1 to 3.0% for each of Zr and V;
0.002 to 0.5% for Sb, Sn and Ge,
0.001 to 0.01% for B, Ca and rare earth elements, and 0.2 to 5.0% for Co
After subjecting the steel slab containing to hot rolling to cold rolling or warm rolling to a final thickness, the final temperature reached 650-1150 ° C and 900 ° C-400 ° C. A high-strength non-directional electromagnetic member having excellent magnetic properties, characterized by subjecting to finish annealing with a cooling rate of 1 ° C./s or more and then aging at a temperature of 400 ° C. to 650 ° C. Steel plate manufacturing method.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in detail for each component.
(Steel composition)
First, the component composition range and the reason for the limitation will be described. In this specification,% representing the steel composition means mass% unless otherwise specified.
C: 0.02% or less If the C content exceeds 0.02%, the iron loss is remarkably deteriorated due to magnetic aging, so the content is limited to 0.02% or less.
[0018]
Si: 4.5% or less In addition to being useful as a deoxidizing agent, Si has a large effect of reducing iron loss of an electromagnetic steel sheet by increasing electric resistance. In addition, solid solution strengthening contributes to strength improvement. The effect becomes remarkable when the content of the deoxidizing agent is 0.05% or more. In order to reduce iron loss and strengthen solid solution, the content is made 0.5% or more, more preferably 1.2% or more. However, when the content exceeds 4.5%, the rollability of the steel sheet is greatly deteriorated, so that the content is limited to 4.5% or less.
[0019]
Mn: 3.0% or less Mn is an element effective for improving hot brittleness in addition to an element effective for improving strength by solid solution strengthening, and is preferably contained at 0.05% or more. However, since excessive addition causes deterioration of iron loss, its content is limited to 3.0% or less.
[0020]
Al: 3.0% or less Al is effective as a deoxidizing agent, and is preferably contained at 0.5 ppm or more. However, excessive addition causes a reduction in rollability, so the amount of addition is limited to 3.0% or less.
[0021]
P: 0.50% or less P is very effective for increasing the strength because a large amount of solid solution strengthening ability can be obtained even if a relatively small amount of P is added, and is preferably contained at 0.01% or more. On the other hand, excessive content causes embrittlement due to segregation, resulting in grain boundary cracking and reduction in rollability. Therefore, the content is limited to 0.50% or less.
[0022]
Next, the addition of Cu and Ni is the most important matter in the present invention.
Cu: 0.2% or more and 4.0% or less Cu forms a fine precipitate by the aging treatment, and brings about a significant increase in strength with almost no deterioration of iron loss (history loss). To obtain the effect, 0.2% or more is required under the condition containing Ni described later. On the other hand, if it exceeds 4.0%, coarse precipitates are formed, so that the iron loss deteriorates greatly and the strength increase margin decreases. Therefore, the content of Cu is in the range of 0.2% to 4.0%, preferably 0.3% to 2.0%.
[0023]
Ni: 0.5% or more and 5.0% or less Ni itself is an effective element for increasing the strength by solid solution strengthening, but when added together with Cu, it affects the solid solution precipitation state of Cu, and is extremely affected by aging. This has the effect of stably depositing fine Cu precipitates. As a result, it is possible to greatly enhance the effect of increasing strength by Cu aging precipitation. Ni also has the effect of reducing the surface defects of the hot-rolled sheet called hege and improving the yield of the steel sheet. In order to obtain these effects, it is necessary to add at least 0.5% or more. On the other hand, if it exceeds 5.0%, the effect is saturated and only the cost is increased. Therefore, the upper limit is set to 5.0%. More preferably, it is in the range of 1.0% or more and 3.5% or less.
[0024]
The other elements are Fe (iron) and unavoidable impurities. It is desirable that S and N as unavoidable impurities are each 0.01% or less from the viewpoint of iron loss.
[0025]
The basic composition of the non-oriented electrical steel sheet according to the present invention is as described above. In addition to the above components, Zr, V, Sb, Sn, Ge, B, Ca, rare earth elements known as elements for improving magnetic properties And Co can be added alone or in combination. However, the amount added should not be detrimental to the purpose of the present invention. In particular,
0.1 to 3.0% for Zr and V
0.002 to 0.5% for Sb, Sn, and Ge
0.001 to 0.01% for B, Ca and rare earth elements
0.2-5.0% for Co
It is.
[0026]
In the present invention, the precipitation of Cu after aging can be optimized by setting the above component ranges and the following production conditions, and as a result, the tensile strength TS (MPa) of the product is represented by the following formula. CTS or more.
CTS = 5600 [% C] +87 [% Si] +15 [% Mn] +70 [% Al] +430 [% P] +37 [% Ni] + 22d− ^{1 / 2} + 230
[0027]
Here, the coefficient of each element is a term corresponding to the amount of solid solution or precipitation strengthening per 1% of each element, and d is the average crystal grain size (diameter: mm) of the product, which was etched with a nital etching solution or the like. The sample is observed with an optical microscope, and is obtained as a circle equivalent diameter of crystal grains from the observation visual field area and the number of crystal grains in the visual field. The smaller the average crystal grain size d, the higher the strength due to the refinement of the crystal grains, but the lower the core loss. Therefore, the crystal grain size d is adjusted according to the required strength and iron loss characteristics.
[0028]
(Production method)
In order to produce a high-strength non-oriented electrical steel sheet excellent in iron loss according to the present invention, first, in a converter or an electric furnace, a steel melted to the above-described predetermined component is continuously cast or formed. A steel slab is formed by slab rolling after the ingot. Next, the obtained slab is hot-rolled, subjected to hot rolling slope annealing as necessary, and subjected to cold rolling or warm rolling two or more times with one or intermediate annealing sandwiched to a product thickness, and finished. Anneal and then aging. Further, at any stage after the final annealing, an insulating coating is applied and baked as required.
[0029]
In the present invention, since the strength is increased in a subsequent step without increasing the amount of Si in the material, it can be manufactured by cold rolling. Since warm rolling has the effect of improving the texture and improving iron loss and magnetic flux density, warm rolling can also be employed.
[0030]
The above-mentioned finish annealing is intended to remove distortion due to rolling and to obtain an appropriate crystal grain size by recrystallization in order to obtain necessary iron loss characteristics. The appropriate crystal grain size depends on the required iron loss level, but is generally 20 to 200 μm. For that purpose, the final ultimate temperature of the finish annealing needs to be 700 ° C. or more. On the other hand, when annealing exceeding 1150 ° C. is performed, coarse grains are formed and grain boundary cracks are easily caused, and iron loss deterioration accompanying oxynitriding of the steel sheet surface is increased. Therefore, the upper limit is set to 1150 ° C.
[0031]
The inventors have found that when utilizing the fine precipitation of Cu, the cooling conditions of the finish annealing are important. That is, in the cooling process of the finish annealing, if the cooling rate from the solid solution temperature of Cu to 600 ° C. is not sufficiently fast, some of the Cu precipitates coarsely during cooling, which becomes a factor of deterioration of iron loss, and Even after subsequent aging annealing, the amount of coarse precipitates increases and sufficient strength may not be obtained in some cases. Here, when only Cu and no Ni are contained, the cooling rate needs to be 10 ° C./s or more in a temperature range of 900 ° C. to 400 ° C.
[0032]
However, when containing Ni in the range of the present invention together with Cu, if the cooling rate is 1 ° C./s or more, coarse precipitation during cooling can be suppressed, and subsequent aging treatment does not cause significant deterioration of iron loss. A sufficient increase in strength is obtained. That is, when aging treatment is performed by adding Cu and Ni in combination, stable characteristics can be obtained under more various finish annealing conditions than in the case where Ni is not added. Therefore, at the time of cooling after finish annealing, the temperature range from 900 ° C. when the maximum temperature reached in annealing exceeds 900 ° C., and from the finish annealing temperature to 400 ° C. when the maximum temperature reached annealing is 900 ° C. or less. The cooling rate at 1 ° C./s or more.
If the above conditions are satisfied, the strength after the subsequent aging treatment is
CTS = 5600 [% C] +87 [% Si] +15 [% Mn] +70 [% Al] +430 [% P] +37 [% Ni] + 22d− ^{1 / 2} + 230
The above can be considered.
[0033]
The subsequent aging treatment is performed at a temperature of 400 to 650 ° C. That is, when the temperature is lower than 400 ° C., precipitation of fine Cu becomes insufficient, and high strength cannot be obtained. On the other hand, when the temperature exceeds 650 ° C., the Cu precipitates become coarse, so that the iron loss is deteriorated and the amount of increase in strength is also reduced, so that an electromagnetic steel sheet having a good strength-iron loss balance cannot be obtained. The appropriate aging time also depends on the processing temperature, but is preferably from 10 min to 1000 h. The aging treatment may be carried out at any time before the application and baking of the insulating film, after the baking, and after processing such as press punching.
[0034]
【Example】
Example 1
As shown in Table 1, a steel slab consisting of 3% of Si, 0.2% of Mn, and 0.3% of Al and having the contents of Cu and Ni changed as the basic components and the balance of iron and unavoidable impurities was used. After hot rolling to a sheet thickness of 2.0 mm, as shown in Table 2, after performing no annealing or hot rolling sheet annealing at 1000 ° C. for 300 s, pickling and cold rolling of a finished sheet thickness of 0.35 mm were performed. went. Furthermore, after performing the final annealing of holding the soaking at a maximum temperature of 950 ° C. for 30 seconds, the cooling rate in a temperature range of 900 ° C. to 400 ° C. was 6 ° C./s. Thereafter, an insulating coating was applied and baked, and then heat-treated at 550 ° C. for 5 hours for aging to obtain a product plate.
[0035]
The product sheet thus obtained was evaluated for iron loss characteristics and mechanical characteristics. In addition, the component composition in the product plate was almost the same as in the slab stage. The iron loss was evaluated by the Epstein method using equal amounts of samples in the rolling direction and the direction perpendicular to the rolling direction. The mechanical properties were evaluated using the average of samples cut out from the rolling direction and the direction perpendicular to the rolling direction. Table 1 shows the results.
[0036]
Further, as a conventional electromagnetic steel sheet having a high tensile strength by known solid solution strengthening, crystal grain refinement strengthening, precipitation strengthening, and the like, the following steel sheets were also experimentally manufactured.
That is, as an example using solid solution strengthening, as shown in Table 2, C: 0.002%, Si: 4.5%, Mn: 0.2%, P: 0.01%, Al: 0. After hot-rolling a steel slab containing 6%, W: 1.0% and Mo: 1.0%, with the balance being iron and unavoidable impurities, the steel slab was annealed at 900 ° C. for 30 s for 400 seconds. The steel sheet was warm-rolled at a temperature of 0 ° C. to finish to a thickness of 0.35 mm, and was subjected to finish annealing at 950 ° C. × 30 seconds.
As an example using solid solution strengthening and grain refinement, as shown in Table 2, C: 0.005%, Si: 3%, Mn: 0.2%, P: 0.05%, and Ni: 4 A steel containing 0.5% and the balance consisting of iron and unavoidable impurities was hot-rolled, then cold-rolled to a thickness of 0.35 mm, and then subjected to finish annealing at 800 ° C. for 30 s.
As an example using precipitation strengthening, as shown in Table 2, C: 0.03%, Si: 3.2%, Mn: 0.2%, P: 0.02%, Al: 0.65%, A steel containing 0.003% of N, 0.018% of Nb and 0.022% of Zr, and the balance consisting of iron and unavoidable impurities is hot-rolled, cold-rolled to a thickness of 0.35 mm, and then heated to 750 ° C. × 30s finish annealing was performed.
In each case, no aging treatment was performed.
[0037]
[Table 1]

[0038]
[Table 2]

[0039]
According to the steel sheet No. Steel sheets Nos. 7 to 13 are comparative examples having a base composition. While having excellent magnetic properties almost equal to that of No. 1, significant high strength is obtained. Further, a steel sheet No. which is a conventional high-strength electromagnetic steel sheet is used. Compared to 14 to 16, it has a remarkably low iron loss or high magnetic flux density, and is excellent in strength-magnetic property balance.
[0040]
Example 2
The comparative steel C and the invention steel J shown in Table 1 were hot-rolled to a sheet thickness of 2.0 mm, and then subjected to hot-rolled sheet annealing at 1000 ° C. for 300 s, and then pickled and finished to a sheet thickness of 0.35 mm. Cold rolling was performed. Furthermore, finish annealing was carried out at a maximum temperature of 950 ° C. for 30 seconds so as to maintain a uniform temperature, and cooling was performed by changing the cooling rate in a temperature range of 900 ° C. to 400 ° C. to various conditions shown in Table 3. Thereafter, an insulating coating was applied and baked to obtain an annealed plate. The obtained annealed sheet was subjected to a heat treatment at 550 ° C. for 5 hours for aging to obtain a product sheet. The product sheet thus obtained was evaluated for iron loss characteristics and mechanical characteristics. In addition, the component composition in the product plate was almost the same as that in the slab stage. The results are shown in Table 3 and FIGS.
[0041]
[Table 3]

[0042]
Steel C is a steel sheet No. As shown in FIGS. 18 and 19, when the cooling rate is relatively high at 10 ° C./s or more, excellent magnetic properties and high strength are exhibited. It tends to decrease. On the other hand, the invention steel J to which an appropriate amount of Ni was added together with Cu is the steel sheet No. As shown in Nos. 22 to 24, it was possible to stably achieve both excellent magnetic properties and high strength under a wide range of cooling rate conditions.
[0043]
Example 3
A steel having a composition shown in Table 4 consisting of iron and unavoidable impurities was hot-rolled to a thickness of 2.0 mm, and then subjected to no annealing or hot-rolled sheet annealing at a temperature shown in Table 5 for 300 s, Pickling and cold rolling to a predetermined thickness were performed. Furthermore, finish annealing was performed at a temperature shown in Table 5 for 30s soaking, and cooling was performed at a cooling rate of 6 ° C / s in a temperature range of 900 ° C to 400 ° C. Thereafter, an insulating coating was applied and baked to obtain an annealed plate. The obtained annealed sheet was subjected to aging treatment for 10 hours at the temperature shown in Table 5 for aging to obtain a product sheet. The product sheet thus obtained was evaluated for iron loss characteristics and mechanical characteristics. The results are also shown in Table 5. In addition, the component composition in the product plate was almost the same as in the slab stage. Table 5 shows that all the samples have excellent magnetic properties and very high strength properties in each steel sheet grade.
[0044]
[Table 4]

[0045]
[Table 5]

[0046]
【The invention's effect】
As described above, according to the present invention, it is possible to stably provide an electromagnetic steel sheet having excellent magnetic properties and high strength.
[Brief description of the drawings]
FIG. 1 is a diagram showing the effect of the finish annealing cooling rate on iron loss after aging treatment.
FIG. 2 is a graph showing the effect of a finish annealing cooling rate on tensile strength after aging treatment.

Claims (4)

In mass%,
C: 0.02% or less,
Si: 4.5% or less,
Mn: 3.0% or less,
Al: 3.0% or less,
P: 0.50% or less,
Ni: contains 0.5% or more and 5.0% or less and Cu: 0.2% or more and 4.0% or less, has a component composition of balance Fe and inevitable impurities, and has a tensile strength represented by the following formula. A high strength non-oriented electrical steel sheet having excellent magnetic properties, characterized by having a CTS (MPa) or higher.
CTS = 5600 [% C] +87 [% Si] +15 [% Mn] +70 [% Al] +430 [% P] +37 [% Ni] + 22d− ^{1 / 2} + 230
Here, d: average grain size of crystal grains (mm) In claim 1, one or more selected from Zr, V, Sb, Sn, Ge, B, Ca, a rare earth element and Co as a component composition,
0.1 to 3.0% for each of Zr and V;
0.002 to 0.5% for Sb, Sn and Ge,
0.001 to 0.01% for B, Ca and rare earth elements, and 0.2 to 5.0% for Co
High strength non-oriented electrical steel sheet with excellent magnetic properties characterized by containing In mass%,
C: 0.02% or less,
Si: 4.5% or less,
Mn: 3.0% or less,
Al: 3.0% or less,
P: 0.50% or less,
After hot rolling is performed on a steel slab containing Ni: 0.5% or more and 5.0% or less and Cu: 0.2% or more and 4.0% or less, cold rolling or warm rolling is performed. After the final sheet thickness, the final reaching temperature is 650 to 1150 ° C and the cooling rate in the temperature range of 900 ° C to 400 ° C is 1 ° C / s or more. A method for producing a high-strength non-oriented electrical steel sheet having excellent magnetic properties, characterized by aging at a temperature of In mass%,
C: 0.02% or less,
Si: 4.5% or less,
Mn: 3.0% or less,
Al: 3.0% or less,
P: 0.50% or less,
Ni: contains 0.5% or more and 5.0% or less and Cu: 0.2% or more and 4.0% or less, and is further selected from Zr, V, Sb, Sn, Ge, B, Ca, rare earth elements, and Co. One or two or more
0.1 to 3.0% for each of Zr and V;
0.002 to 0.5% for Sb, Sn and Ge,
0.001 to 0.01% for B, Ca and rare earth elements, and 0.2 to 5.0% for Co
After subjecting the steel slab containing to hot rolling to cold rolling or warm rolling to a final thickness, the final temperature reached 650-1150 ° C and 900 ° C-400 ° C. A high-strength non-directional electromagnetic member having excellent magnetic properties, characterized by subjecting to finish annealing with a cooling rate of 1 ° C./s or more and then aging at a temperature of 400 ° C. to 650 ° C. Steel plate manufacturing method.

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