JPH11302741A - Production of nonoriented silicon steel sheet low in core loss and nonoriented silicon steel sheet low in core loss - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicon steel sheet lower in core loss after finish annealing compared to the conventional case. SOLUTION: This method is the one in which a slab contg., by weight, <=0.005% C, 1.0 to 4.0% Si, 0.05 to 1.0% Mn, <=0.2% P, <=0.005% (including zero) N, 0.1 to 1.0% Al, <=0.001% (including zero) S and Sb+Sn/2=0.001 to 0.05%, and the balance substantial Fe is subjected to hot rolling and is thereafter subjected to cold rolling and finish annealing to produce a nonoriented silicon steel sheet. In this case, the primary finish annealing is executed at <=850 deg.C, and after that, the secondary finish annealing is executed at >=850 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a non-oriented electrical steel sheet having a low iron loss and used for a motor core, a transformer core, and the like.

[0002]

2. Description of the Related Art In recent years, electromagnetic steel sheets having lower iron loss have been demanded from the viewpoint of energy saving of electric equipment. In order to reduce the iron loss, it is effective to increase the crystal grain size.
% Of medium- and high-grade non-oriented electrical steel sheets, increase the finish annealing temperature to about 1000 ° C, lower the line speed during annealing, and increase the annealing time to increase the grain size. I have.

In order to improve the grain growth during the finish annealing, it is effective to reduce the amount of inclusions and precipitates in the steel sheet. For this reason, attempts have been made to render the inclusions and precipitates harmless, and particularly in high-grade materials, attempts have been made to reduce the S content from the viewpoint of preventing precipitation of MnS.

[0004] For example, Japanese Patent Publication No. 56-22391 discloses that S is contained in steel of 2.5 to 3.5% Si and 0.3 to 1.0% of Al.
A technique for reducing iron loss by setting the content of O to 50 ppm or less and the content of O to 25 ppm or less is disclosed.

In Japanese Patent Publication No. 2-50190,
Si: 2.5-3.5%, Al: 0.25-1.0% S in steel 15p
There is disclosed a technique for reducing iron loss by setting pm or less, O to 20 ppm or less, and N to 25 ppm or less.

Further, Japanese Patent Application Laid-Open No. Hei 5-140647 discloses that S: 2.0 to 4.0% and Al: 0.10 to 2.0%
A technique for reducing iron loss by reducing Ti to 30 ppm or less and Ti, Zr, Nb, and V to 50 ppm or less, respectively, is disclosed.

[0007]

However, in order to achieve a further reduction in iron loss, it is impossible to reduce the amount of inclusions and precipitates only by a conventional method. What is desired is the current situation. The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electromagnetic steel sheet having a lower iron loss after finish annealing than a conventional one by using a new technique.

[0008]

The gist of the present invention is to reduce the iron loss by limiting the amounts of S, Sb, and Sn contained in a steel sheet to predetermined ranges and further optimizing the conditions of the finish annealing. An object of the present invention is to obtain a very low non-oriented electrical steel sheet.

[0009] That is, the first for solving the above-mentioned problem.
Means in weight%, C: 0.005% or less, Si: 1.0 to 4.0
%, Mn: 0.05 to 1.0%, P: 0.2% or less, N: 0.005% or less (including 0), Al: 0.1 to 1.0%, S: 0.001% or less (0
Slabs containing Sb + Sn / 2 = 0.001-0.05%, the balance being substantially Fe, after hot rolling, then cold rolling and finish annealing to produce non-oriented electrical steel sheets In the method of performing the first finish annealing at a temperature of 850 ° C. or less,
Thereafter, a second finish annealing is performed at a temperature of 850 ° C. or higher, which is a method for producing a non-oriented electrical steel sheet with low iron loss (Claim 1).

[0010] A second means for solving the above-mentioned problems is as follows.
% By weight, C: 0.005% or less, Si: 1.0 to 4.0%, Mn: 0.0
5 to 1.0%, P: 0.2% or less, N: 0.005% or less (including 0), Al: 0.1 to 1.0%, S: 0.001% or less (including 0), S
b + Sn / 2 = 0.001 to 0.005%, the balance being substantially hot-rolled after the slab substantially made of Fe, and then subjected to cold rolling and finish annealing to produce a non-oriented electrical steel sheet,
A method for producing a non-oriented electrical steel sheet having a low iron loss, wherein the first finish annealing is performed at a temperature of 850 ° C. or lower, and then the second finish annealing is performed at a temperature of 850 ° C. or higher. 2). That is, Sb + Sn /
The range of 2 is further limited to 0.001 to 0.005%.

A third means for solving the above-mentioned problems is as follows: C: 0.005% or less, Si: 1.0 to 4.0%, Mn: 0.05% by weight.
1.0%, P: 0.2% or less, N: 0.005% or less (including 0), Al: 0.1 to 1.0%, S: 0.001% or less (including 0), S
b + Sn / 2 = 0.001 to 0.05%, the remainder being substantially hot-rolled after the slab substantially made of Fe, and then subjected to cold rolling and finish annealing to produce a non-oriented electrical steel sheet, Perform the first finish annealing at a temperature of 850 ° C or less for 20 seconds or more,
Thereafter, a second finish annealing is performed at a temperature of 850 ° C. or more for 10 seconds or more, which is a method for producing a non-oriented electrical steel sheet with low iron loss (Claim 3). That is, the annealing time before and after the finish annealing of the first means is specified in a specific range.

A fourth means for solving the above-mentioned problem is as follows.
% By weight, C: 0.005% or less, Si: 1.0 to 4.0%, Mn: 0.0
5 to 1.0%, P: 0.2% or less, N: 0.005% or less (including 0), Al: 0.1 to 1.0%, S: 0.001% or less (including 0), S
b + Sn / 2 = 0.001 to 0.005%, the balance being substantially hot-rolled after the slab substantially made of Fe, and then subjected to cold rolling and finish annealing to produce a non-oriented electrical steel sheet,
The first finish annealing is performed at a temperature of 850 ° C or less for 20 seconds or more, and then the second finish annealing is performed at a temperature of 850 ° C or more for 10 seconds.
A method for producing a non-oriented electrical steel sheet with low iron loss, wherein the method is performed for at least seconds. That is, the second
The annealing time before and after the finish annealing in the means of
In the same specific range as the means.

[0013] In each of the above means, "the remainder is substantially
The phrase "Fe" means that those containing other trace elements including unavoidable impurities fall within the scope of the present invention, as long as the effects of the present invention are not lost. Also, Sb + Sn / 2
If the value is within a predetermined range, only one of Sb and Sn may be included. In the present specification,% and ppm indicating the component values of steel indicate weight% and ppm by weight, respectively, unless otherwise specified.

A fifth means for solving the above-mentioned problems is as follows.
A non-oriented electrical steel sheet manufactured by any one of the first to fourth means (claim 5).

(History leading to the invention, and the reasons for limiting the contents of S, Sb, Sn and the conditions of the finish annealing) Was investigated in detail.

First, in order to investigate the effect of S on the iron loss, C: 0.0025%, Si: 1.65%, Mn: 0.20%, P: 0.
01%, Al: 0.31%, N: 0.0021%, S content is tr. ~ 25ppm
In a laboratory, the steel changed in the above range was melted in a vacuum, hot-rolled, annealed at 950 ° C for 3 minutes in a 100% H ₂ atmosphere, pickled, and then cold-rolled to a thickness of 0.5 mm. Rolling was performed. Subsequently, at 950 ° C. in an atmosphere of 10% H ₂ -90% N _{2 in} an annealing atmosphere.
The annealing was performed for 2 minutes. FIG. 1 shows the relationship between the S content of the sample thus obtained and the iron loss W _15/50 (marked by x in the figure). Magnetic properties were measured by a 25 cm Epstein test.

FIG. 1 shows that when S is set to 10 ppm or less, a large reduction in iron loss is achieved, and a material of W _15/50 = 3.2 W / kg can be obtained. This is because grain growth was improved by reducing S. From the above, in the present invention, the range of the S content is limited to 10 ppm or less, but more preferably 5 ppm or less.

However, when the S content is 10 ppm or less, the decrease in iron loss is gradual, and even if the S content is further reduced, the iron loss is only about 3.1 W / kg. The present inventors considered that the reduction of iron loss was inhibited by the extremely low S material of S ≦ 10 ppm due to unknown factors other than MnS, and observed the structure with an optical microscope. As a result, a remarkable nitride layer was recognized on the surface layer of the steel sheet in the region of S ≦ 10 ppm. In contrast, in the region where S> 10 ppm, the nitrided layer was slight. It is considered that this nitrided layer was formed during the finish annealing performed in the nitriding atmosphere.

The cause of the acceleration of the nitridation reaction accompanying the reduction of S is considered as follows. That is, since S is an element which is easily concentrated on the surface and the grain boundaries, S> 10 ppm
In the region of S, S is concentrated on the surface of the steel sheet to suppress the adsorption of nitrogen during finish annealing, while in the region of S ≦ 10 ppm, S
It is considered that the effect of suppressing nitrogen adsorption by the catalyst decreased.

The present inventors have considered that the nitrided layer which is remarkably generated in the extremely low S material may hinder the growth of crystal grains in the surface layer portion of the steel sheet and suppress the decrease in iron loss. Under such a concept, if the present inventors can add an element which can suppress nitrogen adsorption and does not hinder the excellent grain growth of the ultra-low S material, the iron of the ultra-low S material Based on the idea that the loss could be further reduced, we conducted various studies and found that it was effective to add a trace amount of Sb.

FIG. 1 shows the results of a test performed under the same conditions on a sample in which 40 ppm of Sb was added to the components of the sample shown by the crosses, with the circles. Focusing on the iron loss reduction effect of Sb, in the region of S> 10 ppm, the iron loss becomes 0.0
Although it decreases only by about 2 to 0.04 W / kg, in the region of S ≦ 10 ppm, the iron loss is reduced by about 0.10 W / kg by adding Sb. When the S content is small, the iron loss reducing effect of Sb is reduced. Is recognized. However, even with the Sb-added material, a slight surface nitride layer was observed. This is because Sb surface segregated after hot-rolled sheet annealing,
It is considered that, since it is removed by pickling performed after the hot-rolled sheet annealing, the effect of preventing nitriding during the subsequent high-temperature finish annealing is weakened.

Here, high-temperature annealing during finish annealing is indispensable from the viewpoint of reducing iron loss due to coarsening of crystal grains. But,
Since high-temperature annealing simultaneously causes surface nitriding to become apparent, it is necessary to segregate Sb on the steel sheet surface before high-temperature annealing. For this reason, the method of performing the surface segregation treatment of Sb by performing low-temperature annealing which does not generate nitridation in the first stage of the finish annealing, and examining the method of performing the coarsening of the crystal grains by performing the high-temperature annealing in the second stage was studied.

In order to find an appropriate finish annealing pattern, C:
0.0026%, Si: 1.62%, Mn: 0.20%, P: 0.010%, A
l: 0.30%, S: 0.0004%, N: 0.0020%, Sb: 0.004%
Was melted in a laboratory in a vacuum, hot-rolled, then annealed at 950 ° C. for 5 minutes in a 100% H ₂ atmosphere, pickled, and cold-rolled to a thickness of 0.5 mm. Finish annealing is the first stage (primary)
Was subjected to low-temperature annealing and subsequent (secondary) high-temperature annealing, and each annealing temperature and annealing time were variously changed. Note that the finish annealing atmosphere was 10% H ₂ -90% N ₂ .

FIG. 2 shows the relationship between the pre-annealing temperature (primary finish annealing temperature) and the iron loss W _15/50 during the finish annealing. Where S
The primary finish annealing time for segregating b was 1 min, and the secondary finish annealing was 950 ° C. × 1 min.

FIG. 2 shows that the iron loss is reduced when the primary finish annealing temperature is 850 ° C. or less. Observation of the microstructures of these materials showed that nitriding was observed in the surface layer of the steel sheet in the materials whose primary finish annealing temperature was over 850 ° C, even though Sb was added. This is considered to be because the steel sheet was exposed to a high-temperature nitriding atmosphere before Sb segregated on the steel sheet surface, so that the nitriding effect of Sb was not sufficiently exerted and nitriding occurred. From the above, in the present invention, the primary finish annealing temperature is specified to be 850 ° C. or less.

FIG. 3 shows the relationship between the post-annealing temperature (secondary annealing temperature) during the finish annealing and the iron loss W _15/50 . here,
Secondary finish annealing time is 1 min, primary finish annealing is 800 ℃ x
1 minute. FIG. 3 shows that iron loss is reduced when the secondary finish annealing temperature is 850 ° C. or higher. Observation of the structures of these materials revealed that the materials having a secondary finish annealing temperature of less than 850 ° C. did not have sufficient grain growth, and thus did not achieve a sufficient reduction in iron loss. From the above, in the present invention, the secondary finish annealing temperature is specified to be 850 ° C. or higher.

FIG. 4 shows the relationship between the pre-annealing time (primary finish annealing time) and the iron loss W _15/50 during the finish annealing. here,
The primary finish annealing temperature is 800 ° C, and the secondary finish annealing is 950 ° C ×
1 minute. FIG. 4 shows that the iron loss is reduced when the primary finish annealing time is 20 seconds or longer. Observation of the microstructures of these materials showed that for materials with a primary finish annealing time of less than 20 sec, a nitrided layer was observed on the surface layer of the steel sheet.
It was found that segregation was not sufficiently performed. From the above, in the present invention, the preferred primary finish annealing time is specified to be 20 seconds or more.

FIG. 5 shows the relationship between the post-annealing time (secondary annealing time) and the iron loss W _15/50 during the finish annealing. here,
The primary finish annealing temperature is 800 ° C x 1 min.
° C. FIG. 5 shows that the iron loss is reduced when the post-annealing time is 10 seconds or longer. Observation of the microstructures of these materials revealed that materials having a post-annealing time of less than 10 seconds had insufficient grain growth. From the above, in the present invention, the preferable secondary finish annealing time is specified to be 10 sec or more.

In the two-step annealing in the present invention, it is important to perform the surface segregation treatment of Sb by primary low-temperature annealing, and the purpose is simply to suppress nitriding during finish annealing by shortening the high-temperature annealing time. The concept differs greatly from conventional two-step annealing.

Next, to investigate the optimum amount of Sb, C:
0.0026%, Si: 1.60%, Mn: 0.20%, P: 0.020%, A
l: 0.30%, S: 0.0004%, N: 0.0020%, and the Sb amount is tr.
Was vacuum melted steels was varied in a range of ~700ppm at laboratory after hot rolling, subjected to hot rolled sheet annealing of 950 ° C. × 3min at 100% H ₂ atmosphere, after pickling, the sheet thickness 0.5mm Cold rolling was carried out until. Continue in a 10% H ₂ -90% N ₂ atmosphere at 800 ° C x 1
min primary finish annealing was performed, followed by a continuous secondary finish annealing at 950 ° C. × 1 min. FIG. 6 shows the relationship between the Sb content and the iron loss W _15/50 .

FIG. 6 shows that iron loss is reduced in the region where the amount of Sb is 10 ppm or more. However, when Sb is further added and Sb> 50 ppm, the iron loss increases again. In order to investigate the cause of the increase in iron loss in the region of Sb> 50 ppm, the structure was observed with an optical microscope.
As a result, although the surface layer fine grain structure was not recognized, the average crystal grain size was slightly smaller. Although the cause is not clear, Sb is an element that easily segregates at the grain boundaries,
It is considered that the grain growth was reduced due to the grain boundary drag effect.

However, even when Sb is added up to 700 ppm, the iron loss is better than that of Sb-free steel. From the above, in the present invention, the Sb content is set to 10 ppm or more, and the upper limit is set to 500 ppm from the viewpoint of cost. From the viewpoint of iron loss, the content is desirably 10 ppm or more and 50 ppm or less.

The iron loss reducing effect described above is also observed when Sn, which is a surface segregation element similar to Sb, is contained in an amount of 20 ppm or more, and iron loss is slightly increased when the content is 100 ppm or more. From this, Sn is set to 20 ppm or more, and the upper limit is 1000 p
pm. From the viewpoint of iron loss, the content is desirably 20 ppm or more and 100 ppm or less. Furthermore, even when Sb and Sn are combined, iron loss is reduced when Sb + Sn / 2 is added at 10 ppm or more, and iron loss is slightly increased when Sb + Sn / 2 is added at 50 ppm or more. Was. From this, when Sb and Sn are added in combination, the upper limit is set to 10 ppm or more in Sb + Sn / 2, and the upper limit is set due to cost problems.
500 ppm. Also, from the viewpoint of iron loss, desirably 10 ppm
At least 50 ppm.

(Reasons for Limiting Other Components) Next, reasons for limiting other components will be described. C: C is 0.005% or less because of the problem of magnetic aging. Si: Since Si is an element effective for increasing the specific resistance of the steel sheet, it is added in an amount of 1.0% or more. On the other hand, if it exceeds 4.0%, the magnetic flux density decreases with the decrease in the saturation magnetic flux density, so the upper limit is set.
4.0%. Mn: Mn is 0.1% to prevent red hot brittleness during hot rolling.
It is required to be not less than 05%, but if it is not less than 1.0%, the magnetic flux density is reduced. P: P is an element necessary for improving the punching property of the steel sheet, but if added in excess of 0.2%, the steel sheet will be embrittled, so that the content is set to 0.2% or less. N: N is set to 0.005% or less to increase the amount of AlN and increase iron loss when the content is large. Al: Al is an element effective for increasing the specific resistance, like Si, but if it exceeds 1.0%, the magnetic flux density decreases with a decrease in the saturation magnetic flux density, so the upper limit is set to 1.0%. Also,
If it is less than 0.1%, the lower limit is set to 0.1% because AlN becomes finer and the grain growth is reduced.

(Manufacturing method) In the present invention, if the prescribed component values including S, Sb and Sn are within a predetermined range and the annealing pattern at the time of finish annealing is within the range of the present invention,
The other manufacturing method may be a method of manufacturing a normal non-oriented electrical steel sheet. That is, the molten steel blown in the converter is degassed and adjusted to a predetermined component, and subsequently casting and hot rolling are performed. The finishing temperature and the winding temperature during hot rolling do not need to be particularly specified, and may be a temperature in a range where a normal non-oriented electrical steel sheet is manufactured. In addition, hot-rolled sheet annealing after hot-rolling may be performed, but is not essential. Next, after pickling, after a predetermined temperature by cold rolling, the primary finish annealing 850.
C. or lower, and the secondary finish annealing is performed at a temperature of 850 C. or higher. In addition, the primary finish annealing and the secondary finish annealing may be performed continuously, or after the primary finish annealing, the steel plate may be cooled once and then subjected to the secondary finish annealing. Furthermore when performing rolling across at two or more cold intermediate annealing, 850 an annealing temperature of the intermediate annealing carried out in H ₂ -N ₂ mixed atmosphere
By setting the temperature to not more than ° C., it can be used as a substitute for the primary finish annealing, and the scope of the present invention includes such a form.

[0036]

EXAMPLES Using the steel shown in Table 1, after degassing by blowing in a converter, the steel was adjusted to predetermined components and cast.
After the slab was heated at 1140 ° C. for 1 hour, hot rolling was performed to a thickness of 2.3 mm. The hot rolling finishing temperature was 800 ° C. The winding temperature was 610 ° C. After the winding, hot-rolled sheet annealing was performed under the conditions shown in Table 2. Thereafter, pickling was performed, cold rolling was performed to a sheet thickness of 0.5 mm, and annealing was performed under finish annealing conditions shown in Table 2. Magnetic measurements were performed using 25 cm Epstein specimens. Table 2 also shows the magnetic properties of each steel sheet. Table 1 and Table 2
No. correspond.

In Tables 1 and 2, steel sheets No. 1 to No. 15 are examples of the present invention, and steel sheets No. 16 to No. 27 are comparative examples. As can be seen from Tables 1 and 2, in Examples of the present invention, a higher iron loss W _15/50 was selected without lowering the magnetic flux density B ₅₀ than in Comparative Examples.

Among the examples, No. 3 and No. 4 steel sheets and No. 7
In the steel sheet of the above, Sb + Sn / 2 exceeds 0.005%, and does not satisfy the conditions of claims 2 and 4. In addition, No. 11 steel plate
The primary finish annealing time does not satisfy the conditions of claims 3 and 4, and the steel sheet No. 13 does not satisfy the secondary finish annealing time of the claims 3 and 4. Therefore, the iron loss _{W15 / 50} of these steel sheets is slightly higher than those of the other examples.

Among the comparative examples, the steel sheet No. 16 had the S content and the value of Sb + Sn / 2, and the steel sheet No. 17 had the value of Sb + Sn / 2 out of the range of the present invention. Therefore, the iron loss W _15/50 is high. No. 18 steel sheet and No. 19 steel sheet have the primary finish annealing temperature exceeding the range of the present invention, so that the iron loss W
_15/50 is higher. Further, the steel sheet of No. 20 also has a higher iron loss W _15/50 because the secondary finish annealing temperature is lower than the range of the present invention.

Since the C content exceeds the range of the present invention, the steel sheet No. 21 has not only a high iron loss W _15/50 but also a problem of magnetic aging. Since the steel content of No. 22 has a Si content outside the range of the present invention, the iron loss W _15/50 is low, but the magnetic flux density B ₅₀ is low. No.23 steel plate is Mn
Since the content is lower than the range of the present invention, the iron loss W _15/50 is high. Since the steel sheet No. 24 has a Mn content exceeding the range of the present invention, the iron loss W _15/50 is low, but the magnetic flux density B ₅₀ is low. The No. 25 steel sheet has a high iron loss W _15/50 because the N content exceeds the range of the present invention. The steel sheet No. 26 has a higher iron loss W _15/50 because the Al content is lower than the range of the present invention. On the other hand, No.
The steel sheet No. 22 has a low iron loss W _15/50 but a low magnetic flux density B ₅₀ because the Al content exceeds the range of the present invention.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

As described above, according to the first aspect of the present invention, C: 0.005% or less and Si:
1.0-4.0%, Mn: 0.05-1.0%, P: 0.2% or less, N: 0.
005% or less (including 0), Al: 0.1 to 1.0%, S: 0.001%
Below (including 0), after hot rolling a slab containing Sb + Sn / 2 = 0.001-0.05% and the balance substantially consisting of Fe, then cold-rolled and finish-annealed for non-directional electromagnetic In the method of manufacturing a steel sheet, the primary finish annealing is performed at a temperature of 850 ° C. or lower, and then the second finish annealing is performed at a temperature of 850 ° C. or higher. Low non-oriented electrical steel sheets can be manufactured.

According to a second aspect of the present invention, the range of Sb + Sn / 2 is limited to 0.001 to 0.005% in the first aspect of the present invention. Can be manufactured.

The invention according to claims 3 and 4 is:
In these inventions, the primary finish annealing time is limited to 20 seconds or more, and the secondary finish annealing time is limited to 10 seconds or more.
Furthermore, a non-oriented electrical steel sheet with low iron loss can be manufactured.

The non-oriented electrical steel sheet according to claim 5 is suitable for being widely used as an electrical material requiring low iron loss, such as a motor core and a transformer core.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the amount of S and iron loss after finish annealing.

FIG. 2 is a diagram showing the relationship between pre-finishing annealing temperature (primary finishing annealing temperature) and iron loss.

FIG. 3 is a diagram showing a relationship between post-finishing annealing temperature (secondary finishing annealing temperature) and iron loss.

FIG. 4 is a view showing a relationship between pre-finishing annealing time (primary finishing annealing time) and iron loss.

FIG. 5 is a diagram showing a relationship between post-finishing annealing time (secondary finishing annealing time) and iron loss.

FIG. 6 is a graph showing the relationship between the amount of Sb and iron loss.

Claims (5)

[Claims] C .: 0.005% or less by weight, Si: 1.0 to
4.0%, Mn: 0.05-1.0%, P: 0.2% or less, N: 0.005%
Or less (including 0), Al: 0.1 to 1.0%, S: 0.001% or less
(Including 0), Sb + Sn / 2 = 0.001 to 0.05%, the remainder being substantially rolled after hot rolling a slab substantially made of Fe, then cold rolling and finish annealing In the method for producing a non-oriented electrical steel sheet having a low iron loss, the first finish annealing is performed at a temperature of 850 ° C. or less, and then the second finish annealing is performed at a temperature of 850 ° C. or more. Manufacturing method. 2. C: 0.005% or less by weight, Si: 1.0 to less.
4.0%, Mn: 0.05-1.0%, P: 0.2% or less, N: 0.005%
Or less (including 0), Al: 0.1 to 1.0%, S: 0.001% or less
(Including 0), Sb + Sn / 2 = 0.001 to 0.005%, the remainder being substantially rolled after hot rolling a slab consisting essentially of Fe, then cold rolling and finish annealing In the method for producing a non-oriented electrical steel sheet having a low iron loss, the first finish annealing is performed at a temperature of 850 ° C. or less, and then the second finish annealing is performed at a temperature of 850 ° C. or more. Manufacturing method. 3. The composition according to claim 1, wherein C: 0.005% or less, Si: 1.0 to
4.0%, Mn: 0.05-1.0%, P: 0.2% or less, N: 0.005%
Or less (including 0), Al: 0.1 to 1.0%, S: 0.001% or less
(Including 0), Sb + Sn / 2 = 0.001 to 0.05%, the remainder being substantially rolled after hot rolling a slab substantially made of Fe, then cold rolling and finish annealing In the method of manufacturing a first finish annealing at a temperature of 850 ° C. or less 2
A method for producing a non-oriented electrical steel sheet having a low iron loss, wherein the non-oriented electrical steel sheet has a low iron loss for at least 0 second, and then performs a second finish annealing at a temperature of 850 ° C or more for 10 seconds or more. 4. C: 0.005% or less by weight, Si: 1.0 to
4.0%, Mn: 0.05-1.0%, P: 0.2% or less, N: 0.005%
Or less (including 0), Al: 0.1 to 1.0%, S: 0.001% or less
(Including 0), Sb + Sn / 2 = 0.001 to 0.005%, the remainder being substantially rolled after hot rolling a slab consisting essentially of Fe, then cold rolling and finish annealing In the method of manufacturing a first finish annealing at a temperature of 850 ° C. or less 2
A method for producing a non-oriented electrical steel sheet having a low iron loss, wherein the non-oriented electrical steel sheet has a low iron loss for at least 0 second, and then performs a second finish annealing at a temperature of 850 ° C or more for 10 seconds or more. 5. A non-oriented electrical steel sheet manufactured by the method for manufacturing a non-oriented electrical steel sheet according to any one of claims 1 to 4.