JPH06100939A - Production of low core loss grain-oriented silicon steel sheet - Google Patents

Abstract

PURPOSE:To produce a grain-oriented silicon steel sheet having low core loss at a low cost by subjecting a silicon steel slab to hot rolling and cold rolling to regulate its sheet thickness into a final one, thereafter forming grooves in the specified direction on the surface of the cold rolled sheet, filling the oxides, sulfates or the like of specified elements therein and executing decarburizing annealing and finish annealing. CONSTITUTION:A silicon steel slab contg. 2.0 to 4.5% Si is subjected to hot rolling and is successively subjected to cold rolling for one time or >=two times including process annealing to roll into a steel sheet having a final sheet thickness, e.g. of 0.23mm. On the surface of this cold rolled steel sheet, linear grooves having 30 to 300mum width and 5 to 100mum depth are formed at 60 to 90 degrees at intervals of >=1mm, and one kind among the oxides, sulfates or the like of Sn, B and Sb is filled in the grooves. Next, this steel sheet is subjected to decarburizing annealing and finish annealing, by which the grain-oriented silicon steel sheet improved in core loss value and excellent in magnetic properties can be produced at a relatively low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a grain-oriented electrical steel sheet having excellent magnetic properties, which is particularly suited to a core material for transformers and other electric equipment.

[0002]

2. Description of the Related Art Grain-oriented electrical steel sheets are used as iron cores for transformers and other electric equipment, and are required to have excellent magnetic properties, and particularly low iron loss. This iron loss can be roughly expressed as the sum of hysteresis loss and eddy current loss.By using an inhibitor with a strong inhibitory force, the hysteresis loss can be increased to the Goss orientation, that is, the (110) <001> orientation. It has been significantly reduced by the integration, the reduction of the impurity element that causes the generation of the pinning factor when the domain wall moves when magnetized, and the like. Regarding eddy current loss, on the other hand, increasing the Si content to increase electrical resistance, reducing the steel plate thickness, and forming a coating on the surface of the steel plate with a coefficient of thermal expansion different from that of the base steel The reduction has been attempted by applying tension, reducing the magnetic domain width by miniaturizing the crystal grains, and the like.

Further, various techniques for forming grooves in a steel sheet have been proposed for the purpose of reducing eddy current loss. These methods are a method of locally forming grooves in the steel sheet after final finish annealing, that is, secondary recrystallization, and a method of subdividing the magnetic domains by the demagnetizing effect, and the same manner as in the steel sheet before final finishing annealing. It is roughly divided into the method of forming.

As the former groove forming means, Japanese Patent Publication No. 50-35679
Japanese Patent Laid-Open No. 63-76819 discloses that the insulating coating and the underlying coating are locally removed by laser irradiation and then electrolytic etching is performed.
JP-A-53579 discloses that strain relief annealing is performed after pressing with a gear type roll. However, the method of machining or gear-type roll has a disadvantage that the space factor of the product transformer is lowered because a large burr is generated in the vicinity of the formed groove. In addition, the method disclosed in Japanese Patent Laid-Open No. 63-76819 requires a step of partially removing the underlying film or insulating film that has been formed, forming grooves by etching, and then forming these films again. Therefore, there is a disadvantage that the film thickness of the product is increased and the space factor is decreased, and that the cost is increased and the productivity is decreased.

As the latter groove forming means, JP-A-59-19752
No. 0 discloses a method of forming grooves in a steel sheet before final finish annealing. According to this method, the above disadvantages are eliminated, but the effect of reducing iron loss is small, and it is difficult to sufficiently satisfy the demands of customers.

Further, JP-A-60-255926 and 61-11728
No. 4 gazette discloses that a groove is formed by locally removing the coating on the steel sheet after finish annealing by irradiating a laser beam and then etching to form a groove, and filling the groove with a substance different from that of the steel plate base metal. A method has been proposed in which a greater iron loss reduction effect is obtained as compared with the case where only the steel is formed. However, in the case where this method is actually performed, it is necessary to partially remove the coating film that has been formed once and then etch it, and then to form these coating films again, which reduces the space factor of the product and reduces the cost. This has the disadvantage of increasing productivity and decreasing productivity.

Further, in Japanese Patent Publication No. 54-23647, a steel sheet after cold rolling or after decarburization annealing is subjected to mechanical processing such as shot peening, thermal treatment such as electron beam or S, Al.
There is disclosed a method of forming a secondary recrystallized grain growth prevention treated region and an untreated region by a chemical method using diffusion of Se, Sb, Sb and the like. This aims to improve the magnetic flux density and reduce the iron loss by directly controlling the secondary recrystallization, but considering the actual operation, it is necessary to introduce a uniform strain by a mechanical method such as shot peening. However, in the case of thermal treatment with an electron beam or the like, there is a problem that the device becomes large in size and the cost is increased. On the other hand, S, Al, Se
However, the application of compounds such as Sb has the advantage that they can be inexpensively performed by high-speed printing, etc., but in a line that is transported at a high speed, the applied substance scatters and the applied amount changes, and it is also necessary to wind the coil after processing. At this time, there was a problem that the coating substance was peeled off. Further, these methods also have a problem that the obtained magnetic characteristics vary greatly.

On the other hand, in Japanese Examined Patent Publication No. 63-1372, the surface of the steel sheet before the final finish annealing is locally processed, and a dilute aqueous solution useful for controlling the rate of secondary recrystallization is applied piecewise. A method is disclosed. The local processing of this method is plastic processing with a projection roll or irradiation with an electron beam or a laser beam, and any of them is intended to promote diffusion of a coating substance by the introduced strain. However, in reality, the introduced strain is not uniform, and on the contrary, there is a problem that the magnetic properties vary due to uneven diffusion of the coating material.

[0009]

SUMMARY OF THE INVENTION The present invention advantageously solves the above problems and proposes a method for stably producing a grain-oriented electrical steel sheet having a low iron loss at a low cost. To aim.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted earnest experiments and studies for the purpose of developing a manufacturing method capable of stably supplying a low iron loss grain-oriented electrical steel sheet without variations in quality, and as a result, finally cold rolled. Completed this invention by newly discovering that even if a groove is locally formed prior to finish annealing and then the groove is filled with a predetermined substance, a lower iron loss can be obtained compared with the conventional method. did.

That is, according to the present invention, the grain-oriented electrical steel material is hot-rolled, and then cold-rolled once or twice or more with an intermediate anneal to obtain a final product sheet thickness, and then decarburization-annealed.
Then, in the method for producing a grain-oriented electrical steel sheet consisting of a series of steps of performing finish annealing, the steel sheet after final cold rolling and before finish annealing is formed with linear grooves extending in a direction substantially orthogonal to the rolling direction, A method for producing a low iron loss grain-oriented electrical steel sheet, characterized in that the linear groove is filled with any one selected from Sn, B and Sb and oxides and sulfates of these elements. Is.

The linear groove has a width of 30 to 300 μm and a depth of 5 to 100 μm and extends at an angle of 60 to 90 ° with respect to the rolling direction, and the linear groove is 1 mm or more in the rolling direction. It is particularly advantageous to reduce the iron loss by arranging them at intervals of.

Here, as the silicon-containing steel which is the material of the present invention, any of the conventionally known component compositions is suitable, and the representative compositions are as follows. C: 0.01 to 0.10 wt% (hereinafter simply referred to as%) C is a component useful not only for the refinement of the structure during hot rolling and cold rolling but also for the development of Goss orientation, and at least
Addition of 0.01% or more is preferable. However, if the content exceeds 0.10%, the Goss orientation is rather disordered, so the upper limit is preferably about 0.10%.

Si: 2.0 to 4.5% Si increases the specific resistance of the steel sheet and effectively contributes to the reduction of iron loss, but if it exceeds 4.5%, the cold rolling property is impaired, while if it is less than 2.0%, the specific resistance is reduced. Not only decreases but also secondary recrystallization
Since the crystal orientation is randomized by α-γ transformation during the final high-temperature annealing performed for purification, and a sufficient iron loss improving effect cannot be obtained, the Si content is preferably set to about 2.0 to 4.5%.

Mn: 0.02 to 0.12% Mn needs to be at least about 0.02% in order to prevent hot embrittlement, but if it is too much, the magnetic properties deteriorate, so the upper limit is preferably set to about 0.12%. .

As the inhibitor, so-called MnS, MnSe
There are systems and AlN systems. In the case of MnS and MnSe, at least one selected from Se and S: 0.005 to 0.
06% Se and S are both effective elements as inhibitors that control the secondary recrystallization of grain-oriented silicon steel sheets. From the viewpoint of securing the suppression power, at least about 0.005% is required, but if it exceeds 0.06%, the effect is impaired, so it is preferable to set the lower and upper limits to about 0.01% and 0.06%, respectively.

In the case of AlN system, Al: 0.005 to 0.10%, N: 0.004 to 0.015% Al and N ranges are set to the above ranges for the same reason as in the case of MnS and MnSe systems described above. . The above MnS, MnSe and AlN types can be used together.

As the inhibitor component, the above-mentioned S, S
e, Al, Cu, Sn, Cr, Ge, Sb, Mo, Te, Bi and P
Etc. are advantageously suited, so that a small amount can be included in each case. Here, the preferred addition ranges of the above components are Cu, Sn, Cr: 0.01 to 0.15%, Ge, Sb, Mo, Te,
Bi: 0.005 to 0.1%, P: 0.01 to 0.2%, and each of these inhibitor components can be used alone or in combination.

The present invention will be described in detail below. First,
The experimental results that have led to the completion of the present invention will be described.
After heating a grain-oriented electrical steel slab containing 3.40% Si, hot-rolling it, then cold-rolling it to a thickness of 0.23 mm, and then stamping it with a projection roll or irradiating it with an electron beam. Was linearly formed at a distance of 3 mm in the rolling direction in a direction substantially orthogonal to the rolling direction to form linear grooves. After that, SnO ₂ made into a slurry by adding water was applied to the linear grooves, and then ordinary decarburization annealing and finish annealing were performed.

A sample was taken from each of the steel sheets thus obtained, and the magnetic properties were measured. Further, a steel plate was sampled from the periphery of the same cold-rolled coil, and a sample with only groove formation and a sample without groove formation treatment were also prepared as comparative materials.

As shown in FIG. 1 showing the measurement results of the magnetic characteristics, it is understood that the magnetic characteristics are improved by filling the linear grooves formed according to the above method with SnO ₂ .

Next, after heating the grain-oriented electrical steel slab containing 3.40% of Si, it is hot-rolled and then cold-rolled to a plate thickness of 0.23 mm.
Width 0.2 mm in the direction where the non-coated part is almost orthogonal to the rolling direction
And, the coating was applied so as to remain linearly at an interval of 3 mm in the rolling direction. Then, electrolytic etching was performed to introduce linear grooves with a depth of 20 μm on the surface of the steel sheet. The resist ink was applied by gravure offset printing, and a gravure ink containing an alkyd resin as a main component was used. Electrolytic etching is carried out in a NaCl aqueous solution with a current density of 10 A / dm ² and electrolysis time of 20 s.
It went on condition of.

Then, electric Sn plating was applied to the formed groove. As the plating bath, 60 g of stannous sulfate, 80 g of sulfuric acid, 100 g of cresol sulfonic acid, 1.0 g of β-naphthol and 2 g of gelatin were dissolved in 1 liter of ion-exchanged water, and the bath temperature was 30 ° C. .
The electroplating conditions were a current density of 5 A / dm ² , a tank voltage of 10 V, and a distance between the electrodes of 30 mm, and 5 to 20 s. After that, the resist agent was removed, and ordinary decarburization annealing and finish annealing were performed.

Magnetic properties were measured after taking samples from the steel sheets thus obtained. Further, a steel plate was sampled from the periphery of the same cold-rolled coil, and a sample with only groove formation and a sample without groove formation treatment were also prepared as comparative materials.

As shown in the Epstein measurement results in FIG. 2, it can be seen that by applying Sn plating to the groove, a lower iron loss can be obtained as compared with the case of only the groove. It was observed that fine crystal grains were generated in the Sn plated portion.

Here, comparing the measurement result of FIG. 2 with the measurement result of FIG. 1 described above, it can be seen that the iron loss value is more stable in the measurement result shown in FIG. That is, the iron loss is more stabilized when the groove is formed by etching than when the groove is formed by the projection roll or the electron beam. Although the reason for this is not clear, in the case of groove processing using a projection roll or an electron beam, uneven strain may occur in the steel sheet and the diffusion of substances in the groove may also become uneven, while groove processing by etching is performed. Is considered to be because no distortion occurs in the steel sheet.

Therefore, the groove is formed by electrolytic etching or the like.
Chemical method such as electrochemical method and pickling is desirable for industrial production
However, it is not necessary to limit to these methods. Na
In the case of electrolytic etching, the pole distance should be between the anode and cathode.
There are no specific rules as long as the transfer of children is possible,
50 mm or less is desirable in terms of transmission efficiency. Electrolytic etching solution is publicly known
For example, NaCl aqueous solution or KCl aqueous solution is used,
Current density is 5-40A / dm ²Is desirable. On the other hand, pickling treatment
Chemical etching such as FeCl is used as an etching solution._3, H
NO_3,HCl or the like can be used.

Further, an experiment under the same conditions was carried out by changing the width and depth of the groove formed in the steel sheet, the angle with respect to the rolling direction, and the interval in the rolling direction. The results are shown in Figs. 3 to 6, respectively, and the width of the groove is 30 to 300 µ.
m, depth 5-100 μm, angle 60-90 to the rolling direction
In order to reduce iron loss, it is desirable to form them at intervals of 1 mm or more in the rolling direction. The groove may have a continuous linear shape, or a dotted line, a broken line, and a wavy line.

The material to be filled in the groove is first Sn,
B and Sb. For these filling methods, electroplating methods, electroless plating methods, and vapor phase plating methods such as PVD and CVD are advantageously applicable. Further, even if these substances are sufficiently crushed and water is added to make a slurry, the same effect can be obtained. Note that Sn, B and Sb
The effect of improving the magnetic properties is also observed when the oxide or sulfate of each element is attached to the groove. As the oxide, SnO ₂ , SnO, B ₂ O ₃ , Sb ₂ O ₃ , and as the sulfate, SnSO ₄ ,
Sb ₂ (SO ₄ ) ₃ is applicable. As for the effect of the groove formation, the treatment on one side of the steel plate is sufficient, but the treatment on both sides may be performed. Incidentally, the steel sheet according to the present invention is, after flattening annealing, of course used as a material for laminated core without performing stress relief annealing, even if subjected to stress relief annealing as a material for wound core,
Its effect does not diminish.

[0030]

According to the present invention, if any one selected from Sn, B and Sb and oxides and sulfates of these elements is filled after forming the groove, a lower iron loss than ever can be obtained. In addition to the demagnetizing effect due to the linear groove,
It is presumed that the filling of B, S, Sb, etc. progresses the grain refinement without impairing the orientation of the secondary recrystallized grains. By filling the groove with the substance, the adhered substance does not scatter even on a line conveyed at a high speed, and the substance in the groove is not peeled off by contact even during coil winding.

[0031]

EXAMPLES Example 1 C: 0.043%, Si: 3.36%, Mn: 0.070%, Mo: 0.0
A silicon steel slab containing 13%, Se: 0.019%, and Sb: 0.023% was heated at 1360 ° C for 3 hours and then hot-rolled.
After forming a hot rolled sheet having a thickness of 2.4 mm, cold rolling was performed twice at 970 ° C. with intermediate annealing for 3 minutes to obtain a final cold rolled sheet having a thickness of 0.23 mm. Next, a resist ink as a masking agent was applied to the steel sheet before the final finish annealing so that the non-applied portion remained linearly with a width of 0.2 mm in the direction perpendicular to the rolling direction and an interval of 3 mm in the rolling direction. After that, electrolytic etching is performed in a NaCl aqueous solution under conditions of a current density of 10 A / dm ² , an electrolysis time of 20 s, and a distance between the electrodes of 30 mm, so that the depth of the resist ink non-coated portion, that is, the exposed portion of the base metal is about 20 μm. After forming the groove, the resist agent was removed. Subsequently, Sn, B, and Sb, which were made into a slurry form by sufficiently pulverizing and then adding water, were applied to the formed groove portions with a brush.

After the above treatment, decarburization annealing, final finish annealing, and flattening annealing were performed. For comparison, a steel plate was sampled from the vicinity of the groove forming material sampling portion of the same final cold rolling coil as the groove forming material, and the same series of steps as the groove forming material was performed without forming the groove. The results of measuring the magnetic properties of the steel sheet thus obtained are shown in Table 1.

[0033]

[Table 1]

Example 2 A slab having the same composition as in Example 1 was treated in the same manner to obtain a resist-printed steel sheet in 30% HNO ₃ for 15 to 30 seconds.
By immersing, a groove having a depth of about 20 μm was formed, and Sn and Sb were applied to the groove by electroplating.
Here, Sn plating is 60 g of first sulfuric acid Sn, 80 g of sulfuric acid, and Sn100 of cresol sulfonic acid per 1 liter of ion-exchanged water.
g, β-naphthol (1.0 g) and gelatin (2 g) were dissolved, the bath temperature was 30 ° C., and the electroplating conditions were a current density of 5 A / dm ² , a time of 5 to ²⁰ g, and a gap between electrodes: 30 mm. . The Sb plating is performed by dissolving 52 g of antimony trioxide, 150 g of potassium citrate and 180 g of citric acid in 1 liter of ion-exchanged water and using a bath at a temperature of 55 ° C. : 3.5 A / dm ² , time: 5 to ^{20 s} , distance between poles: 30
went as mm. After that, the resist agent was removed, and ordinary decarburization annealing and finish annealing were performed.

For comparison, a steel plate was sampled from the vicinity of the groove forming material collecting portion of the same final cold rolling coil as the groove forming material, and a sample in which no groove was formed and a sample in which the groove was formed were prepared. A series of steps similar to those described above were performed. The results of measuring the magnetic properties of the steel sheet thus obtained,
It shows in Table 2.

[0036]

[Table 2]

Example 3 A resist ink was used as a masking agent on a steel sheet (sheet thickness: 0.23 mm) after final cold rolling and before final finish annealing as in Example 1, and its non-coated portion is orthogonal to the rolling direction. After applying it so that it becomes a dotted line with a width of 0.2 mm (point spacing 0.2 mm), electrolysis under conditions of current density: 10 A / dm ² , electrolysis time: 20 s and distance between electrodes: 30 mm in NaCl aqueous solution. By etching, a groove extending in a dotted line with a depth of about 20 μm was formed in the resist ink non-applied portion, that is, the exposed portion of the base metal. Then, the formed groove was subjected to Sn plating and Sb plating in accordance with the conditions of Example 2, and then the resist agent was removed. Then, usual decarburization annealing and finish annealing were performed.

For comparison, a steel plate was sampled from the vicinity of the groove forming material collecting portion of the same final cold rolling coil as the groove forming material, and a sample without groove formation and a sample with groove formation were prepared. A series of steps similar to those described above were performed. The results of measuring the magnetic properties of the steel sheet thus obtained,
It shows in Table 3.

[0039]

[Table 3]

Example 4 C: 0.03%, Si: 3.36%, Mn: 0.070%, Se: 0.019
%, Al: 0.025%, N: 0.0090% and Sb: 0.023%, a silicon steel slab is heated at 1360 ° C. for 3 hours and hot-rolled into a hot rolled sheet having a thickness of 2.4 mm. 10 for hot rolled coil
Annealing was performed at 00 ° C for 1 minute, and cold rolling was performed to a thickness of 1.3 mm. After that, cold rolling was performed twice at 1000 ° C. with intermediate annealing for 1 minute to obtain a final cold-rolled sheet having a thickness of 0.23 mm. Then, a resist ink as a masking agent was applied to the steel sheet before the final finish annealing so that the non-applied portion remained linearly with a width of 0.2 mm in the direction perpendicular to the rolling direction and an interval of 3 mm in the rolling direction. After that, the current density is 10A in NaCl aqueous solution.
/ Dm ² , electrolysis time of 20 s, and distance between poles of 30 mm, electrolytic etching is performed to form a groove with a depth of about 20 μm in the resist ink non-coated area, that is, the exposed area of the base metal. Removed. Subsequently, Sn, B and Sb, which had been sufficiently pulverized and then added with water to form a slurry, were applied to the formed groove by a brush.

The material that has been subjected to the above treatment is subjected to decarburization annealing, final finish annealing, and then flattening annealing, and then at 800 ° C for 3
Time strain relief annealing was performed. For comparison, a steel plate was sampled from the vicinity of the groove forming material sampling portion of the same final cold rolling coil as the groove forming material, and the same series of steps as the groove forming material was performed without forming the groove. Table 4 shows the results of measuring the magnetic properties of the steel sheet thus obtained.

[0042]

[Table 4]

Example 5 A resist-printed steel sheet obtained by similarly treating a slab having the same composition as in Example 4 was used in 30% HNO ₃ for 15 to 30 seconds.
By immersing, a groove having a depth of about 20 μm was formed, and Sn and Sb were applied to the groove by electroplating.
Here, Sn plating is 60 g of first sulfuric acid Sn, 80 g of sulfuric acid, and Sn100 of cresol sulfonic acid per 1 liter of ion-exchanged water.
g, β-naphthol (1.0 g) and gelatin (2 g) were dissolved, the bath temperature was 30 ° C., and the electroplating conditions were a current density of 5 A / dm ² , a time of 5 to ²⁰ g, and a gap between electrodes: 30 mm. . The Sb plating is performed by dissolving 52 g of antimony trioxide, 150 g of potassium citrate and 180 g of citric acid in 1 liter of ion-exchanged water and using a bath at a temperature of 55 ° C. : 3.5 A / dm ² , time: 5 to ^{20 s} , distance between poles: 30
went as mm. After that, the resist agent was removed, and ordinary decarburization annealing and finish annealing were performed.

For comparison, a steel plate was sampled from the vicinity of the groove forming material collecting portion of the same final cold rolling coil as the groove forming material, and a sample without groove formation and a sample with groove formation were prepared. A series of steps similar to those described above were performed. The results of measuring the magnetic properties of the steel sheet thus obtained,
It shows in Table 5.

[0045]

[Table 5]

Example 6 After the same final cold rolling as in Example 4, the resist ink was used as a masking agent on the steel sheet (sheet thickness 0.23 mm) before final finishing annealing, and the non-coated portion was orthogonal to the rolling direction. After applying it so as to form a dotted line with a width of 0.2 mm (point spacing 0.2 mm), electrolysis under conditions of current density: 10 A / dm ² , electrolysis time: 20 s, and distance between electrodes: 30 mm in NaCl aqueous solution. By etching, a groove extending in a dotted line with a depth of about 20 μm was formed in the resist ink non-applied portion, that is, the exposed portion of the base metal. Then, the formed groove was subjected to Sn plating and Sb plating in accordance with the conditions of Example 2, and then the resist agent was removed. Then, usual decarburization annealing and finish annealing were performed.

As a comparison, a steel plate was sampled from the vicinity of the groove forming material collecting portion of the same final cold rolling coil as the groove forming material, and a sample without groove formation and a sample with groove formation were prepared. A series of steps similar to those described above were performed. The results of measuring the magnetic properties of the steel sheet thus obtained,
It shows in Table 6.

[0048]

[Table 6]

Example 7 A resist-printed steel sheet obtained by similarly treating a slab having the same composition as that of Example 4 was used in 30% HNO ₃ for 15 to 30 seconds.
After immersing to form a groove with a depth of about 20 μm, the resist agent was removed, and water was added to the groove to form a slurry Sn.
It was filled with O ₂ , B ₂ O ₃ , Sb ₂ O ₃ or SnSO ₄ . Then, these steel sheets were subjected to usual decarburization annealing and finish annealing.

For comparison, a steel plate was sampled from the vicinity of the groove forming material sampling portion of the same final cold rolling coil as the groove forming material, and a sample without groove formation and a sample with only groove formation were prepared. A series of steps similar to those described above were performed. The results of measuring the magnetic properties of the steel sheet thus obtained,
It shows in Table 7.

[0051]

[Table 7]

[0052]

According to the present invention, it is possible to stably manufacture a grain-oriented electrical steel sheet which has a good magnetic property and is stable and which has never been obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing magnetic characteristics after various treatments.

FIG. 2 is a diagram showing magnetic characteristics after various treatments.

3 is a diagram for illustrating the relationship between the decrease amount [Delta] W _17/50 groove width and a low iron loss.

4 is a diagram for illustrating the relationship between the groove depth and low iron loss reduction amount [Delta] W _17/50.

FIG. 5: Angle of groove with respect to rolling direction and low iron loss reduction amount ΔW
It is a diagram for illustrating the relationship between the _17/50.

6 is a diagram showing the relation between the distance and the low iron loss reduction amount [Delta] W _17/50 of the groove.

Claims (2)

[Claims] 1. After hot rolling of a grain-oriented electrical steel material, 1
In the method for producing a grain-oriented electrical steel sheet, which comprises a series of steps of performing cold rolling two or more times with intermediate or intermediate annealing to obtain a final product sheet thickness, and then performing decarburizing annealing and then finish annealing. After forming linear grooves extending in a direction substantially orthogonal to the rolling direction on the steel sheet after rolling and before finish annealing, Sn, B and Sb and oxides and sulfates of these elements are formed in the linear grooves. A method for producing a low iron loss grain-oriented electrical steel sheet, which comprises filling any one selected from the above. 2. Width: 30 to 300 μm and depth: 5 to 100
The linear grooves extending at an angle of 60 to 90 ° with respect to the rolling direction in μm are arranged at intervals of 1 mm or more in the rolling direction.
A method for producing the low iron loss grain-oriented electrical steel sheet described.