JP2001323347A - Nonoriented silicon steel sheet excellent in workability, recyclability and magnetic property after strain relieving annealing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonoriented silicon steel sheet excellent in workability and recyclability, having low core loss and high magnetic flux density, and also excellent in magnetic properties after strain relieving annealing. SOLUTION: The steel sheet has a composition containing, by mass, 1.5-4.0% Si and 0.005-1.50% Mn, also containing C, Al and N in amounts reduced, by mass, to <=0.0050%, <=0.030% and <=0.0030%, respectively, further containing <=0.01 mass %, in total, of Ti and Nb under the condition of <=0.01 mass % V, and having the balance iron with inevitable impurities. In this steel sheet, core loss W15/50 and magnetic flux density B50 are regulated to <=3.20 W/kg and >=(1.650+0.025×W15/50)T, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-oriented electrical steel sheet mainly used for a core material of electrical equipment, and more particularly to a non-oriented electrical steel sheet having excellent magnetic properties after strain relief annealing.

[0002]

2. Description of the Related Art In recent years, with the worldwide movement to save energy such as electric power, there has been a strong demand for higher efficiency of electric equipment. Also, from the viewpoint of reducing the size of electric devices, there is an increasing demand for reducing the size of iron core materials. Furthermore, from consideration for environment,
There is also an urgent need to respond to the recycling of iron core materials in electrical equipment.

In order to increase the efficiency of the electric equipment and reduce the size of the iron core material, it is effective to improve the magnetic properties of the magnetic steel sheet used as the material of the iron core. Here, in the field of conventional non-oriented electrical steel sheets, in order to reduce eddy current loss by increasing electric resistance as a means for reducing iron loss among magnetic properties, in particular, Si, Al and Mn are used. Techniques for increasing the content of have been generally used. However, this method has an essential problem that a reduction in magnetic flux density cannot be avoided.

On the other hand, in addition to simply increasing the content of Si, Al, and the like, it is also necessary to reduce C and S at the same time, or to add B as described in JP-A-58-15143. It is also a generally known method to increase the alloy component, such as adding Ni as described in JP-A-3-281758. With the method of adding these alloy components, although the iron loss is mainly improved, the effect of improving the magnetic flux density is small and not satisfactory. Furthermore, since the hardness of the steel sheet increases with the addition of the alloy and the workability deteriorates, the versatility of processing this non-oriented electrical steel sheet for use in electrical equipment is poor, and its use is extremely limited. Had become.

[0005] In addition, several methods have been proposed to improve the magnetic characteristics by improving the degree of integration of the crystal orientation of the product plate, that is, the texture, by changing the manufacturing process. For example, JP-A-58-181822 discloses that Si: 2.8 to
4.0 mass% and Al: 200 for steel containing 0.3-2.0 mass%
Warm rolling within the temperature range of ~ 500 ° C, {100} <UV
W> The method of developing a tissue is disclosed in
No. 422 discloses that Si: 1.5 to 4.0 mass% and Al:
After hot rolling of steel containing 0.1-2.0 mass%, {100} microstructure is developed by a combination of hot-rolled sheet annealing at 1000 ° C or more and 1200 ° C or less and rolling reduction of 80-90%. Methods are disclosed, respectively.

However, the effect of improving the magnetic properties by these methods is not yet satisfactory. In addition, it is often the case that a customer performs strain relief annealing, and it is also important that the magnetic properties are not degraded after the annealing as a performance required for the non-oriented electrical steel sheet. Furthermore, there remains a problem in workability and recyclability. In other words, if a certain amount of Al is contained in the steel, the hardness of the steel sheet first increases, impairing the workability.In addition, when recycling iron core materials or scrapping at the customer, the electrode of the electric furnace is used. Damages the subject.

Further, when casting a motor shaft or the like by using a recycled iron core, 0.1% by mass or more of Al
When the steel is contained, the surface oxidation of the molten steel proceeds during casting to increase the viscosity, and the filling property of the molten steel in the mold is deteriorated, so that there is also a problem that sound casting is hindered.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide not only excellent workability and recyclability, but also low iron loss and high magnetic flux density, as well as excellent magnetic properties after strain relief annealing. To provide grain-oriented electrical steel sheets.

[0009]

The gist of the present invention is as follows.
It is as follows. (1) Si: 1.5 to 4.0 mass% and Mn: 0.005 to 2.00 mass
%, And each of C, Al and N is C: 0.0050
mass% or less, Al: 0.030 mass% or less, N: 0.0030 mass%
In addition, Ti and Nb are contained in a total range of 0.01 mass% or less under V: 0.01 mass% or less, and the balance is composed of iron and unavoidable impurities, and iron loss W _15/50 : 3.
20W / kg or less and a magnetic flux density _{B 50: (1.650 + 0.025 ×} W
_15/50 ) A non-oriented electrical steel sheet excellent in workability, recyclability and magnetic properties after strain relief annealing characterized by being T or more.

(2) In the above (1), Sb: 0.005
Non-oriented electrical steel sheet with low iron loss and high magnetic flux density, excellent in workability and recyclability, characterized by containing up to 0.50 mass%.

(3) In the above (1) or (2), the hardness of the steel sheet is 200 HV1 or less, and the non-directionality of low iron loss and high magnetic flux density excellent in workability and recyclability. Electrical steel sheet.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to increase the efficiency of a motor or a transformer of an electric device, it is necessary to reduce the copper loss and the iron loss. It is necessary to increase the magnetic flux density of the material and reduce iron loss. However, since a specific resistance increasing component such as Si, which is generally added to reduce iron loss, lowers the saturation magnetic flux density, it is very difficult to achieve both iron loss and magnetic flux density. In this regard, the improvement of the texture is an excellent means for achieving both iron loss and magnetic flux density, but this means has its own limitations.

Under these circumstances, in order to develop a new material, it is very important to first know how to balance the iron loss and the magnetic flux density of the material with a view to improving the efficiency of electric equipment. Becomes important. Then, the present inventors investigated the motor efficiency when various materials were applied to the iron core using a 500 W brushless DC motor that has recently been generally used. Here, the motor efficiency is D
The ratio of output to input for C motor, 92%
If it is above, it can be said that it is extremely high efficiency.

FIG. 1 shows that the iron loss W _15/50 was 3.2 W / kg or less and the magnetic flux density B ₅₀ was (1.650+
0.025 × W _15/50 ) It has been newly found that the motor efficiency is improved when a material having a range satisfying T or more is applied to the iron core. This is a result of adjusting the balance between the iron loss of the material and the magnetic flux density within the above-mentioned range, so that the iron loss and the copper loss in the device are highly balanced. This finding is basically the same for not only DC motors but also AC induction motors and small transformers. Therefore, satisfying the above-mentioned preferred ranges for iron loss and magnetic flux density is a clear guideline for developing new materials.

Next, based on the above findings, the present inventors have made intensive studies on the component composition of the non-oriented electrical steel sheet which can satisfy the above ranges of iron loss and magnetic flux density, and can also secure workability and recyclability. First, Al has conventionally been added as necessary for improving magnetic properties, but it is imperative to reduce Al here because it impairs workability and recyclability.

That is, Al is used in a steel plate manufacturing process to promote oxidation of the steel plate surface, to accelerate the wear of the rolling rolls in the rolling process to inhibit rollability, and to increase the hardness of the steel plate. It is a disadvantageous component in terms of workability, such as increasing the working time and cost by accelerating the deterioration of the mold when the customer performs the punching process. In addition, when casting is performed using scraps of electric equipment and the like, if Al is contained, the surface oxidation of the molten steel proceeds during casting, the viscosity decreases, and the filling property of the molten steel in the mold deteriorates. In addition, a sound casting may not be obtained, and the scrap containing Al becomes poor in recyclability.

Therefore, in order to improve workability and recyclability, it is effective to reduce the Al content. However, on the other hand, a reduction in Al leads to an increase in magnetic properties, especially iron loss. However, according to the study of the inventors, it is newly found that by reducing Al and appropriately adjusting other components in steel, it is possible to satisfy all of workability, recyclability, and magnetic properties. It turned out. In other words, the present inventors have analyzed many experimental results and found that when the amount of Si is sufficient and the amount of N is low, good iron loss characteristics can be obtained without adding Al almost. Was found. Therefore, the following experiment was conducted in order to systematically clarify the effects of the Al content and the N content.

First, C: 0.002 mass% as a component and
Mn: 0.20 mass% as a basic component, containing Si, N and
Various steel ingots containing various amounts of Al were melted. These ingots are heated to 1050 ° C and hot-rolled for 2.
Finished to 3 mm, then subjected to hot-rolled sheet annealing at about 1000 ℃, pickled the annealed steel sheet, cold rolled to a final sheet thickness of 0.35 mm, then about 1000 ℃ × 10 seconds Recrystallization annealing was performed to obtain a product plate. Samples were cut out from these product sheets in parallel with the rolling direction and at right angles to the rolling direction, and the iron loss was measured according to JIS C2550, and the average iron loss was determined. As a result, as shown in FIG. 2, it was quantitatively found that the iron loss was significantly reduced even when the Al content was 0.030 mass% or less only when the Si content was high and the N content was low.

As described above, in a high-grade non-oriented electrical steel sheet having a high Si content, a method of increasing the specific electric resistance by adding Al has conventionally been adopted in order to improve iron loss. In addition, the addition of Al also has the effect of aggregating and coarsening AlN, which is a precipitate in steel that suppresses crystal grain growth, and promoting the growth of crystal grains. In order to obtain these effects, it is necessary to secure a certain amount or more of Al. Conventionally, the content of Al is restricted to a range of at least more than 0.1 mass%, and is usually 0.4 to 0.1 mass%.
It was contained at about 1.0 mass%. However, according to the above experiments of the present inventors, even when the Al content is reduced much more than the range of the prior art, by controlling the N content, a texture that is equal to or better than that when Al is contained is obtained. It is newly found that iron develops and iron loss characteristics improve.

The reason why a good texture is developed by reducing the N content and then the Al content in the raw material component is not always clear, but the inventors have found that the impurity particle size is low. The following is considered in relation to the field movement suppression effect. In other words, by reducing Al, it approaches a crystal lattice arrangement state closer to that of pure iron, so that an inherent difference in the movement speed depending on the grain boundary structure becomes apparent, and the difference in the grain growth process accompanying recrystallization becomes one. Only the grain boundaries move preferentially, and the growth of many magnetically disadvantageous grains such as {111}, {554}, and {321} is suppressed, and {100}
It is considered that the magnetic properties were improved as a result of the texture change in the direction of increasing the strength. In particular, when a sufficient amount of Si is contained and the amount of N is reduced to 0.0030 mass% or less, it is difficult to form AlN precipitates.
It is considered that grain boundary movement in the direction of increasing {100} strength is promoted.

As described above, in the method of improving the magnetic structure by improving the texture without adding a large amount of Al, the amount of Al is reduced, so that the recyclability of the material is improved, and the addition amount of the alloy element is reduced. Therefore, the saturation magnetic flux density can be increased. At the same time, when the addition amount of the alloy element is reduced,
Since the increase in hardness of the steel sheet is suppressed, the workability of the product is ensured, and the advantage that application to general-purpose electrical products is promoted is also obtained.

Next, the inventors studied the effects of trace elements in more detail in order to further enhance the effect of the reduction of Al and N described above. As a result, Ti, Nb
It has been found that by appropriately controlling the amounts of V and V, the effect of the reduction of Al and N can be enhanced, and the deterioration of magnetic properties after strain relief annealing can be avoided. In particular, it has been newly found that it is advantageous to control the amount of V in addition to the amounts of Ti and Nb in a component system in which Al is reduced.

That is, even if the composition of Si, Al and N is specified in a predetermined range, the magnetic properties may be degraded after the strain relief annealing, which is performed as required by the customer. In order to clarify this cause, first, Si: 1.5 to 3.6 mass%, Al: 0.00
01 to 0.0155 mass% and N: about 0.0020 mass%, and further, the content of the trace impurity elements Ti, Nb and V is 0.1%.
Steel ingots varied in the range of 001 to 0.09 mass% were melted and subjected to the experiment. Further, Sb was added to some steel ingots. Then, after heating these ingots to 1050 ° C and finishing them to a thickness of 2.6 mm by hot rolling, they are subjected to hot rolling annealing at about 1020 ° C, pickling the steel sheets, and then cold rolling. Finished to a final thickness of 0.35mm. Then, after cold rolling, about 1000
After recrystallization annealing for 10 seconds at ℃
C. × 2 h of strain relief annealing was performed. From the product sheet after strain relief annealing obtained in this way, samples were cut out in parallel with the rolling direction and at right angles to the rolling direction, and the JIS
The magnetic flux density and iron loss were measured according to C2550, and the average magnetic flux density and iron loss were determined. As a result, the magnetic flux density and iron loss after having organized into B ₅₀ -1.650 -0.025 × W _15/50, as the relationship between the total content and the V content of Ti and Nb, shown in FIG.

As shown in FIG. 3, the amount of Ti + Nb is 0.005 mass
%, The magnetic characteristics after strain relief annealing satisfy the applicable range shown in FIG. 1. Further, by limiting the V content to 0.01 mass% or less,
It was found that even if the allowable amount of Ti + Nb was expanded to 0.01 mass%, the compatible range shown in FIG. 1 could be satisfied.

Next, as shown in FIG. 4, the results of an examination of the iron loss of the product sheet before and after the strain relief annealing show that the iron loss after the strain relief annealing deteriorates when the V content exceeds 0.01 mass%. In some cases, it is difficult to stably obtain magnetic properties. However, when the V content is 0.01 mass% or less, the Ti + Nb content is 0.1%.
It can be seen that in a wide range of 0100 mass% or less, iron loss after strain relief annealing does not deteriorate or conversely increases. As described above, by controlling the amounts of Ti, Nb, and V, the characteristics of B ₅₀ ≧ 1.650 + 0.025 × W _15/50 can be obtained stably, and in particular, the iron loss after strain relief annealing is It turned out that the suppression of the effect was effective.

Here, the reason why the magnetic properties are stabilized by reducing the amounts of Ti, Nb and V in the product sheet is not necessarily clear, but Ti, Nb and V are both nitride-forming elements, and these are fine elements. Precipitation of AlN has a negative effect on texture formation and grain growth
It is considered that this kind of harm is prevented by reducing these to prevent the same kind of harm, and as a result, a good magnetic flux density is obtained.

Although the effect of V on the magnetic properties after the strain relief annealing is not clear, it is not possible to use low Al content Si-containing steel.
When V exceeding 0.01 mass% is contained, the V-based nitride or carbide partially dissolved in hot-rolled sheet annealing or recrystallization annealing precipitates as nitride or carbide during strain relief annealing, and It is considered that as a result of inhibiting movement, iron loss is deteriorated. The total amount of Ti and Nb is 0.01 mass
It is considered that the reason why the iron loss deteriorates when the content exceeds% is that the effect of reducing the amount of V does not reach far because the amount of the precipitate increases.

Further, FIG. 5 shows the results of an investigation on the iron loss of the product sheet before and after the strain relief annealing for the component system in which 0.05% by mass of Sb was added to the above-mentioned material having V of 0.01 mass% or less. Thus, it was also found that when Sb was added, the amount of improvement in iron loss after strain relief annealing became larger than when Sb was not added. Although the reason for this is not clear, it is considered that the segregation behavior of Sb affects the precipitation behavior of V and the like, and the precipitation is suppressed by adding Sb, that is, the precipitation amount is suppressed or the coarse precipitation is promoted.

Next, in the non-oriented electrical steel sheet of the present invention, the Vickers hardness of the steel sheet is preferably regulated to 200 HV1 or less so as not to impair the workability at the consumer. In other words, by reducing Al and suppressing oxidation on the steel sheet surface to avoid premature wear of the mold, the hardness of the steel sheet is controlled to 200 HV1 or less, thereby significantly improving the workability of the steel sheet. It will be improved. On the other hand, if the hardness of the steel plate is 12
0 If it is less than HV1, on the contrary, the punched end face may be distorted or crushed, preventing release from the mold, or increasing the burrs after punching, which may adversely affect the space factor of the steel sheet. Therefore, it is preferable that the pressure be 120 HV1 or more.

The regulation of the hardness of the steel sheet is mainly achieved by reducing the amount of Al. However, if the amount of impurity elements is large, the annealing temperature in the final annealing is insufficient, or When oxidation or nitridation occurs during annealing, it may be difficult to stably obtain a desired hardness. Therefore, it is effective not only to reduce impurities according to the present invention but also to make the annealing in the manufacturing process an atmosphere in which excessive oxidation or nitridation does not occur. In the present invention, since the amount of Al in steel, which is a nucleus of oxidation and nitriding, is reduced, there is an advantage that oxidation and nitriding hardly occur as compared with other steel types.

The addition of Sb, which has an effect of suppressing oxidation and nitridation, is also effective in reducing the hardness of the steel sheet to 200 HV1 or less. Furthermore, the addition of Sb is also effective in suppressing the fine precipitation of AlN in the case of low Al and suppressing the grain growth inhibiting action, thereby promoting the formation of a texture more advantageous in magnetic properties. is there. To obtain these effects, it is preferable to add Sb in the range of 0.005 to 0.50 mass%.

Hereinafter, the reasons for limiting the constituent elements of the present invention will be described in detail. First, as the component composition of the non-oriented electrical steel sheet of the present invention, Si: 1.5 to 4.0 mass% and Mn:
It is essential to contain 0.005 to 2.00 mass%. That is, it is necessary to increase the electric resistance by containing Si to reduce iron loss, and to improve the iron loss, the content of 1.5 mass% or more is required. On the other hand, the content of Si is 4.0 mass%
Above that, the magnetic flux density decreases and the secondary workability of the product deteriorates significantly.
To the range.

Mn is a component necessary for obtaining good hot workability. For that purpose, the content of Mn must be 0.005% by mass or more. On the other hand, if it exceeds 2.00 mass%, the saturation magnetic flux density decreases, so the range is limited to 0.005 to 2.00 mass%.

C must be reduced to 0.0050 mass% or less in order to suppress the deterioration of magnetic aging and sufficiently exhibit the effect of improving the texture by reducing Al. In addition,
The reduction of C may be 0.0050 mass% or less at the stage of molten steel, or even if it exceeds 0.0050 mass% at the stage of molten steel, it may be reduced to 0.0050 mass% or less by decarburization in the middle of the process. It is important that the C content in the steel sheet is 50 ppm or less.

Next, in order to obtain excellent magnetic properties, it is important to reduce the Al content of the steel sheet to 0.030 mass% or less and the N content to 0.0030 mass% or less. That is, the Al content is
If the content exceeds 0.030 mass%, the texture of the product plate is deteriorated and the magnetic flux density is reduced, so that the content is reduced to 0.030 mass% or less, preferably 0.010 mass% or less. In addition, the amount of N is 0.
If the content exceeds 0030 mass%, an AlN precipitate is formed, and the development of texture and the growth of crystal grains during recrystallization annealing are suppressed, and iron loss is greatly deteriorated. Therefore, the N content is 0.0030 mass% or less, preferably Is reduced to 0.0025 mass% or less.

Further, Ti, Nb and V are components that form nitrides and inhibit the formation of texture and the growth of crystal grains. By controlling the total amount and V amount of Ti and Nb, Can be highly compatible with the magnetic characteristics after strain relief annealing. That is, the total amount of Ti and Nb is in the range of 0.01 mass% or less, and the V amount is 0.01 mass%.
If it is below, the precipitation behavior of the nitride or carbide of Ti, Nb and V on the product plate and the precipitation behavior at the time of strain relief annealing are controlled, and the influence of the precipitate which influences the domain wall movement is reduced, and the strain is reduced. The magnetic properties of the product sheet before and after annealing are improved.

On the other hand, if the V content exceeds 0.01 mass%, it is necessary to limit the total amount of Ti and Nb to a narrow range of 0.005 mass% or less, and in particular, a low iron loss can be stably obtained after strain relief annealing. Therefore, it is important that the V content be 0.01 mass% or less.

Sb is an effective component for the form of AlN precipitation and good texture formation during grain boundary movement.
That is, Sb has the function of suppressing the fine precipitation of AlN when the Al content is low, and of suppressing the grain growth inhibiting action, and the segregation behavior of Sb affects the precipitation behavior of V and the like. In addition, the addition of Sb has the function of suppressing the precipitation of V or the like, that is, suppressing the amount of precipitation or promoting coarse precipitation. For that purpose, 0.005 mass% or more is necessary, while 0.5 mass%
If it exceeds the limit, the grain growth will be impaired, so 0.005 to 0.
It is preferable to add in the range of 5 mass%.

It has been confirmed that Ni, Sn, Cu, P, Cr and the like also have an advantageous effect on the formation of the texture, and there is no problem in adding these. However, Ni is 2.0 mass
%, Sn 1.0 mass%, Cu 1.0 mass%, P 0.3 mass
% And more than 3.0 mass%, grain boundary migration is suppressed, and the formation of a texture and the growth of grains are inhibited. Therefore, it is necessary to add each component in a range not exceeding these upper limits. .

Further, REM or Ca can be added at the steel making stage in order to increase the iron loss by coarsening the sulfide. This REM and Ca are mesh metal, CaSi, CaAl,
It can be added with CaO flux or the like. That is, by adding REM or Ca, coarse sulfides (which may contain oxygen) are formed, and iron loss can be improved.

The steel sheet having the above-described composition has the iron loss W
_15/50 ： 3.20W / kg or less and magnetic flux density B ₅₀: (1.650 + 0.
025 x W_15/50 ) It has magnetic properties of T or more and is processed
It has excellent recyclability and recyclability.

By the way, with the molten steel having the above-mentioned composition, a slab may be produced by an ordinary ingot casting method or a continuous casting method, or a thin slab having a thickness of 100 mm or less may be produced by a direct casting method. You may. Next, the slab is heated by a usual method and subjected to hot rolling. Alternatively, the slab may be subjected to hot rolling immediately after casting without heating. In the case of thin slabs, hot rolling may be performed,
The hot rolling may be omitted and the process may proceed to the subsequent steps. Next, hot-rolled sheet annealing is performed as necessary, and after one or more times of cold rolling with intermediate annealing as necessary, continuous annealing is performed, and an insulating coating is applied as necessary. In order to improve the iron loss of the laminated steel sheet, an insulating coating is applied to the steel sheet surface.
It may be a multilayer film composed of more than two kinds of coatings, or may be coated by mixing a resin or the like.

[0043]

EXAMPLE A steel slab having the composition shown in Table 1 was produced by continuous casting. This steel slab is heated at 1090 ° C, finished to a thickness of 2.3 mm by hot rolling, then annealed at 1050 ° C x 30 s, stripped by pickling, and removed at 180 ° C.
Cold rolling at a temperature of 0.35 mm or 0.20 mm
mm or 0.15mm final thickness. Next, recrystallization annealing at 1000 ° C. × 10 s was performed in a hydrogen atmosphere, and a semi-organic coating solution was applied and baked at 300 ° C. to obtain a product.

Samples were cut out from the thus obtained product sheet in parallel with the rolling direction and at right angles to the rolling direction, and the magnetic flux density and iron loss were measured in accordance with JIS C2550. As shown in Table 2, these measurement results show that a product having good magnetic properties was obtained by following the component range of the present invention.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

According to the present invention, it is possible to stably provide a non-oriented electrical steel sheet having excellent workability and recyclability and excellent magnetic properties after strain relief annealing.

[Brief description of the drawings]

FIG. 1 is a diagram showing the influence of magnetic flux density B ₅₀ and iron loss W _15/50 on motor efficiency.

FIG. 2 is a graph showing the influence of Al, Si and N amounts on iron loss W _15/50 .

FIG. 3 is a diagram showing the influence of Ti + Nb amount and V amount on magnetic properties.

FIG. 4 is a diagram showing the influence of the amount of Ti + Nb and the amount of V on the magnetic properties after strain relief annealing.

FIG. 5 is a diagram showing the effect of Sb on magnetic properties after strain relief annealing.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuyuki Hayakawa 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Pref. Chome (without address) F-term in Kawasaki Steel Corporation Mizushima Works (reference) 5E041 AA02 AA19 CA02 CA04 HB11 NN01 NN06 NN13 NN15

Claims (3)

[Claims] (1) Si: 1.5 to 4.0 mass% and Mn: 0.005 to
2.00 mass%, and reduce C, Al and N to C: 0.0050 mass% or less, Al: 0.030 mass% or less, N: 0.0030 mass% or less, and V: 0.01 mass% or less, respectively. Ti and Nb in total
It is contained in the range of 0.01 mass% or less, and the balance is composed of iron and inevitable impurities. Iron loss W _15/50 : 3.20 W / kg or less and magnetic flux density B ₅₀ : (1.650
+ 0.025 × W _15/50 ) T A non-oriented electrical steel sheet having excellent workability, recyclability and magnetic properties after strain relief annealing characterized by being not less than + 0.025 × W _15/50 ) T. 2. The method according to claim 1, wherein the Sb content is 0.005 to 0.005.
Non-oriented electrical steel sheet excellent in workability, recyclability and magnetic properties after strain relief annealing characterized by having a composition containing 0.50 mass%. 3. The non-oriented electrical steel sheet according to claim 1, wherein the steel sheet has a hardness of 200 HV1 or less, and is excellent in workability, recyclability, and magnetic properties after strain relief annealing.