JPH07320922A - One directional electromagnetic steel sheet at low iron loss - Google Patents

Abstract

PURPOSE:To provide the one directional electromagnetic steel sheet in low iron loss further cutting down the iron loss by the formation of linear trenches. CONSTITUTION:Within the title one directional electromagnetic steel sheet in low loss, multiple linear trenches in low iron extending in the intersectional direction with loss, many linear tranches and linear high transpositional density regions the rolling direction are provided at intervals respectively in the rolling directions on the surface of the finish-annealed directional silicon substrate, on the other hand, at least a part of the linear trenches and the high transpositional region are arranged on the position where the linear trenches are out of the formational region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low iron loss grain oriented electrical steel sheet suitable for use in an iron core of a transformer or other electric equipment.

The grain-oriented electrical steel sheet is mainly used as an iron core material of a transformer and is required to have good magnetic characteristics. In particular, it is important that the energy loss when used as an iron core, that is, the iron loss is low.

[0003]

2. Description of the Related Art Conventionally, in order to reduce iron loss,
Various attempts have been made such that the crystal orientation is highly aligned with the (110) [001] orientation, the Si content is increased to increase the electrical resistance of the steel sheet, the impurities are reduced, and the sheet thickness is reduced. Came. As a result, the plate thickness is 0.
For steel plates of 23 mm or less, iron loss W _17/50 (maximum magnetic flux density 1.7
The iron loss when alternating magnetization is performed at a frequency of 50 Hz at T) is 0.9
Although W / kg or less has been produced, metallurgical methods cannot be expected to further improve iron loss.

Therefore, in recent years, various methods of artificially subdividing magnetic domains have been attempted as means for achieving a significant reduction in iron loss. Among them, as one of the methods currently industrialized, there is a method disclosed in Japanese Patent Publication No. 57-2252, in which a surface of a steel sheet after finish annealing is irradiated with a laser. The steel sheet obtained by this method has a locally high dislocation density region introduced by the strong energy of the laser beam. This high dislocation density region causes the 180 ° domain to be subdivided, and a steel sheet with low iron loss can be obtained. However, in the steel sheet thus obtained, since the high dislocation density region disappears due to strain relief annealing and the iron loss deteriorates, there is a drawback that it cannot be used in a wound iron core that requires strain relief annealing. there were.

[0005]

On the other hand, as a technique capable of strain relief annealing, Japanese Patent Publication No. 62-54873 discloses that a steel sheet which has been finish annealed is locally insulated by a laser or mechanical means. After removing the film, the film-removed part is pickled, or by a method such as mechanically scribing directly to the base iron with a knife, etc., a linear groove is locally formed, and then this groove is removed. A method of filling by applying an acid-based tension-imparting coating is also disclosed in Japanese Examined Patent Publication No. 62-53579, in which a steel sheet that has been finish annealed has a depth of more than 5 μm at a load of 90 to 220 kgf / mm ² . A method has been proposed in which, after forming the groove, heat treatment is performed at a temperature of 750 ° C. or higher. further,
Japanese Patent Publication No. 3-99968 discloses a method of introducing linear notches into a steel sheet after the final cold rolling in a direction substantially perpendicular to the rolling direction.

Each of the steel sheets obtained by these methods has a linear groove on the surface thereof, and one of the causes is that the magnetic domains are subdivided by the magnetic poles formed in the vicinity of the groove, which reduces the iron loss. It is believed to be realized.

Although a low iron loss material capable of strain relief annealing was obtained by the above method, the iron loss of such a steel sheet was disclosed in Japanese Examined Patent Publication No. 57-2252 as a result of a detailed investigation thereafter. It was found that it may be slightly inferior to the steel sheet having a linear high dislocation density region.

Therefore, the present invention is intended to provide a grain-oriented electrical steel sheet having an extremely low iron loss, which further promotes the reduction of the iron loss due to the formation of the linear groove.

[0009]

When the inventors investigated the cause of the above-mentioned inferior iron loss reducing effect, it was estimated that there was a difference in the amount of magnetic poles to be introduced compared with the method of introducing a high dislocation density region. did it. Furthermore, based on this assumption, as a result of proceeding with earnest experimental studies on a method of reducing iron loss, by optimizing the arrangement of linear grooves and linear high dislocation density regions,
We have obtained new knowledge that iron loss can be reduced more than ever before.

The present invention is based on the above findings. That is, the present invention has a large number of linear grooves and linear high dislocation density regions extending in a direction intersecting the rolling direction at intervals on the surface of the finish-annealed grain-oriented silicon steel sheet with intervals in the rolling direction. , The linear groove and the high dislocation density region,
A unidirectional electrical steel sheet with low iron loss, which is characterized in that at least a part of the high dislocation density region is placed on the surface of the steel plate in an arrangement outside the region where the linear grooves are formed. Even when the linear groove and the high dislocation density region are crossed and introduced,
It is good if the two do not completely overlap.

Further, in the practice, the inclination of the linear grooves and the linear high dislocation density regions with respect to the direction orthogonal to the rolling direction is
It is advantageously suitable that the width is within 30 °, the linear groove has a width of 0.03 to 0.30 mm and a depth of 0.01 to 0.07 mm, and the high dislocation density region has a width of 0.03 to 1 mm and a depth of 0.01 mm or more.

[0012]

First, the results of the research on which the present invention is based will be described. A 3.2 wt% silicon steel hot-rolled sheet containing MnSe and AlN as inhibitors was rolled to 0.23 mm thickness by two cold rolling steps with intermediate annealing, and then
The following treatments (A) to (E) were performed. (A) After applying an etching resist by gravure offset printing, electrolytic etching is performed to form linear grooves having a width of 0.15 mm and a depth of 0.020 mm at 4 mm intervals in a direction orthogonal to the rolling direction, followed by decarburization annealing, Next, final finishing annealing was performed, and further topcoat coating was performed to obtain a product. (B) The product obtained by performing the same treatment as in (A) was irradiated with a plasma flame at a distance of 4 mm in a direction orthogonal to the rolling direction so as not to overlap the linear groove. A linear high dislocation density region was observed in the irradiated area over a width of 0.30 mm. (C) The product obtained by performing the same treatment as in (A) was irradiated with a plasma flame so that the product was located at the same position as the linear groove at an interval of 4 mm in a direction orthogonal to the rolling direction. (D) Decarburization annealing without final groove formation, final finish annealing, and topcoat coating were applied to obtain a product. (E) The product obtained in (D) was irradiated with a plasma flame at 4 mm intervals in a direction orthogonal to the rolling direction. (B) on the irradiation part
Similarly, a linear high dislocation density region was observed over a width of 0.30 mm.

From the product plate thus obtained, a width of 150 mm was obtained.
And a 280 mm long specimen were sampled and subjected to a single plate magnetic test (SST).
More magnetic properties were measured. The results of this measurement are shown in Table 1.
Where W_17/50Values are magnetic flux density 1.7T, frequency 50Hz
Is the measured value of iron loss in B ₈The value is a magnetizing force of 800 A / m
The magnetic flux density in

[0014]

[Table 1]

As is clear from Table 1, the material (B) having a high dislocation density region between linear grooves is a material having only grooves.
The core loss was lower than that of (A) and the material with only high dislocation density (E). Material (C) in which a high dislocation density region was introduced at the same position as the linear groove also had a slightly lower iron loss than the groove alone, but the iron loss reduction amount was less than that of material (B).

As described above, both the linear groove extending in the direction intersecting the rolling direction and the linear high dislocation density region are formed on the surface of the steel sheet, and the linear groove and the high dislocation density region do not overlap at the same position. It has been clarified that the grain-oriented electrical steel sheet exhibits lower iron loss than ever before. Such a material, especially as a material for a laminated core that does not require stress relief annealing, exhibits superior performance to conventional materials, but when used as a material for wound cores that requires stress relief annealing, it is equivalent to the conventional material. Demonstrate performance.

Here, the high dislocation density region does not overlap with the linear groove at the same position, but the iron loss is lower when introduced between the grooves,
It is considered that the amount of magnetic poles effective for subdividing the magnetic domains increases between the grooves.

According to a detailed investigation by the inventors, if the introduction positions of the linear groove and the high dislocation density region are not the same position,
The purpose of reducing iron loss can be achieved. That is, as shown in FIG. 1 (a), not only the arrangement in which the high dislocation density portion exists in the middle of the linear groove in parallel with the groove, but as shown in FIG. 1 (b), for example,
A high dislocation density region may be formed so as to intersect the linear groove.

Further, as shown in FIGS. 2 (a) to 2 (i), the high dislocation density region may be arranged along the linear groove or partially overlapping so as to extend adjacent to the linear groove. Good. In short,
If the linear groove and the high dislocation density region are not completely overlapped, the iron loss can be sufficiently reduced. Although FIG. 2 shows the case where the linear high dislocation density regions are formed symmetrically on one side or both sides of the linear groove, the case where the high dislocation density regions are formed asymmetrically on both sides is also effective. .

Here, when the high dislocation density region is adjacent to the linear groove, it is desirable that the high dislocation density region is adjacent to the linear groove without leaving a gap but completely overlapping with each other. If at least a part of the above is outside the linear groove, it is effective in reducing iron loss. Even when a gap is formed between the linear groove and the gap, the same effect can be obtained if the gap is smaller than the width of the linear groove. It is desirable that the gap between the high dislocation density region and the linear groove does not exceed 0.50 mm. The introduction of the high dislocation density region can be expected to have a sufficient magnetic domain refining effect even if only on one side of the linear groove, but as shown in FIGS. 2 (e) to (i), it is introduced on both sides of the linear groove. Then, a larger effect can be expected.

The high dislocation density region may be formed in all the linear grooves adjacent to the linear grooves, but the linear grooves to be selected may be selected so that the mutual spacing is wider than that of the linear grooves. You may form it. In this case, it is desirable that the average distance in the rolling direction in the high dislocation density region does not exceed 30 mm for the reason described later.

The high dislocation density region is preferably continuous in the plate width direction along the linear groove, but it may be intermittent in the plate width direction. It was also confirmed that the same effect can be obtained whether the surface forming the linear groove and the high dislocation density region is the same surface of the steel sheet or the opposite surface.

Next, the linear groove and the high dislocation density region will be described more specifically. First, as shown in FIGS. 3 and 4, the relationship between the width and depth of the linear groove formed in a steel plate having a plate thickness of _0.23 mm and the iron loss W _17/50 value of the steel plate in which the groove is introduced is shown in FIG. Width 0.030 mm or more, groove depth 0.010 to 0.07
It can be seen that at 0 mm, a low iron loss of 0.80 W / kg or less can be stably obtained. Although a low iron loss can be obtained when the groove width exceeds 0.30 mm, the magnetic flux density is greatly reduced, so the appropriate range is 0.030 to 0.30 mm.

Further, in FIGS. 5 and 6, the groove width is shown, respectively.
The inclination angle of the linear groove with respect to the direction orthogonal to the rolling direction when 0.20 mm and the groove depth is 0.020 mm, the iron loss W _17/50 value of the steel sheet into which the groove is introduced, the groove interval in the rolling direction and W
The relationship between the _17/50 values is shown below. From these figures, 0.
In order to obtain a low iron loss of 80 W / kg or less, it is found that it is advantageous to introduce the grooves with a groove interval in the rolling direction of 1 to 30 mm and a groove inclination angle of 30 ° or less.

Further, in FIG. 7, by the treatment shown in the above-mentioned condition (A) of the experiment, a steel plate was formed with linear grooves having a width of 0.150 mm and a depth of 0.020 mm at intervals of 4 mm in the direction orthogonal to the rolling direction. FIG. 3 shows the relationship between the width of the high dislocation density region produced when irradiation is performed so that the irradiated portion of the plasma flame is located in the middle of the groove and the iron loss W _17/50 value of the steel sheet that has undergone the treatment. Here, the width of the high dislocation density region is changed by changing the nozzle diameter of the plasma flame irradiation nozzle, and by observing the magnetic domain structure of the irradiation portion with a scanning electron microscope, the high dislocation density in the irradiation portion is increased. The width of the density range was obtained. The depth is 0.
It was set to 15 mm. From FIG. 7, when the width of the high dislocation density region exceeds 1 mm, the iron loss is rather deteriorated as compared with the case where only the groove is formed, while when it is less than 0.030 mm, the effect of reducing the iron loss becomes small. Therefore, the width of the high dislocation density region is preferably 0.030 to 1 mm.

Next, as in the case of FIG. 7, when introducing the high dislocation density region, while keeping the width constant at 0.5 mm, the depth was variously changed, and the depth and the iron loss W of the obtained steel sheet were changed. _{The 17/50} value was investigated. As shown in FIG. 8, the results show that a low iron loss of 0.80 W / kg or less can be stably obtained when the depth of the high dislocation density region is 0.01 mm or more.

Further, FIG. 9 shows the relationship between the spacing in the rolling direction and the iron loss W _17/50 when the width of the high dislocation density region in FIG. 7 is 0.30 mm, and FIG. 10 is orthogonal to the rolling direction. The relationship between the inclination angle of the high dislocation density region and the W _17/50 value with respect to the direction of the _rotation is shown. In addition, in these experiments, the width of the high dislocation density region was 0.30 mm, and the interval in the rolling direction was 4 mm. FIG. 9 and
As is clear from 10, the interval in the high dislocation density region is 1 to 30 m.
It is desirable that m and inclination angle be within 30 °.

The method for producing the grain-oriented electrical steel sheet of the present invention is not particularly limited, but it is essential that the obtained product satisfies all the above-mentioned conditions. Therefore, the following manufacturing method is recommended. That is, the slab for grain-oriented electrical steel sheets is hot-rolled, then hot-rolled sheet is annealed if necessary, and then the final product sheet thickness is obtained by one or two or more cold rolling steps with intermediate annealing, and then. Regarding decarburization annealing After the final finishing annealing is performed, usually, when a finish coating is applied to obtain a product, a linear groove and a high dislocation density region are introduced in any step before and after the final finishing annealing.

The linear grooves can be formed by a method of locally etching, a method of scribing with a blade or the like, a method of rolling with a roll having protrusions, etc., but the most desirable method is to finish the steel sheet after the final cold rolling. This is a method in which an etching resist is attached by printing or the like, and then a linear groove is formed in the non-adhesion region by a treatment such as electrolytic etching. By the way, Japanese Examiner Sho 62-535
The method of rolling the steel sheet after finish annealing with a gear type roll disclosed in Japanese Patent Publication No. 79 can form a groove and a high dislocation density region at the same time. In this case, the width of the high dislocation density region should be 1 mm or less. Is difficult and the iron loss is rather deteriorated, which is not desirable.

The method for forming the high dislocation density region is not particularly limited either, but it can be easily industrialized, for example, as disclosed in JP-A-60.
-The method of irradiating a plasma flame and the method of irradiating a laser beam, which are disclosed in Japanese Patent Publication No. 236271, can be applied.
Since it is not easily affected by the surface condition of the steel sheet, the insulating coating is not destroyed, and there is no need for recoating,
The method of radiating a plasma flame disclosed in Japanese Patent 62-96617 is most recommended.

Further, the component composition range of the present invention is compatible with any of the conventionally known ones, 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 uniform fineness of the structure during hot rolling and cold rolling but also for development of Goss orientation, and at least 0.
The content of 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 ductility 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 the α-γ transformation during the final high-temperature annealing performed for purification, and sufficient annealing improvement hardening cannot be obtained, the Si content is preferably set to about 2.0 to 4.5%.

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

As the inhibitor, so-called MnS, MnS
There are e type and AlN type. 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 components 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 range for the same reason as in the case of MnS and MnSe systems described above. . The above-mentioned MnS, MnSe and AlN systems can be used together.

As the inhibitor component, S and S described above are used.
e, Al, Cu, Sn, Cr, Ge, Sb, Mo, Te, Bi and P
And the like are suitable for use, so that a small amount of each of them can be contained together. 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.

Since the present invention produces a great effect when the high dislocation density region is formed under the proper arrangement according to the position of the formed linear groove, the formation of the linear groove and the high dislocation density are achieved. It is desirable that the formation of the density region is performed independently.

[0038]

【Example】

Example 1 C: 0.070%, Si: 3.3%, Mn: 0.069%, Se: 0.018
%, Sb: 0.024%, Al: 0.021% and N: 0.008% of a 3.3 wt% silicon steel hot-rolled sheet was rolled to 0.23 mm thickness by two cold-rolling steps with intermediate annealing. Apply an etching resist by gravure offset printing, and then perform electrolytic etching and resist stripping in an alkaline solution to form linear grooves with a width of 0.16 mm and a depth of 0.018 mm at 10 ° with respect to the direction orthogonal to the rolling direction. Formed at 3 mm intervals in the rolling direction at an inclination angle. After that, decarburization annealing was performed, and then final finish annealing was performed, and further topcoat coating was applied. Furthermore, for the obtained steel sheet, the following
In accordance with the conditions of (F) to (H), plasma flame was irradiated to each of the regions, and the high dislocation density region (width: 0.4 mm and depth: 0.
15mm) was introduced. The plasma flame has a nozzle hole diameter of 0.
Irradiation was performed under the conditions of an arc current of 7.5 A using a 35 mm nozzle.

Note (F) Irradiation at 6 mm intervals at an inclination angle of 10 ° with respect to the direction orthogonal to the rolling direction so that the irradiation portion is located in the center between the grooves and parallel to the linear grooves (G) Irradiate in the direction that intersects the linear groove. Irradiation angle and interval
Same as (F) (H) Irradiate at the same position as linear groove at 6mm intervals

For comparison, a material was also produced which was subjected to the plasma flame irradiation treatment under the same conditions as (F) without the groove formation treatment (J) and without the plasma flame irradiation treatment (I).

From the width direction of the product coil thus obtained, six 150 × 280 mm test pieces were sampled, and the magnetic characteristics were measured by a single plate magnetic tester without strain relief annealing.
The results are shown in Table 2.

[0042]

[Table 2] From Table 2, it was found that the material in which the high dislocation density region was introduced at the position where it did not overlap the groove had a larger reduction range in iron loss than the comparative example.

Example 2 C: 0.071%, Si: 3.4%, Mn: 0.069%, Se: 0.020
%, Al: 0.023% and N: 0.008%, a hot-rolled sheet of silicon steel was processed by a conventional method into a steel sheet having a thickness of 0.18 mm. This steel sheet was stripped of the insulating coating using an ultrasonic vibrator and then pickled in 30% HNO ₃ solution to extend in the direction perpendicular to the rolling direction, with a width of 0.18 mm and a depth of 0.18 mm. After forming 0.015 mm linear grooves at intervals of 4 mm in the rolling direction, overcoating was applied again and 800 ° C x 3
baked at min. Further, according to the following conditions (K) to (M), the obtained steel sheet was irradiated with a plasma flame to locally expose a high dislocation density region (width: 0.4 mm and depth: 0.15 mm). Introduced. The plasma flame has a nozzle hole diameter of 0.
Irradiation was performed under the conditions of an arc current of 7 A using a 35 mm nozzle.

(K) Irradiation at 4 mm intervals parallel to the linear grooves and with the irradiation part located in the center between the grooves (L) 4 mm at an inclination angle of 15 ° from the direction orthogonal to the rolling direction. Irradiate at intervals (M) Irradiate at the same position as the linear groove at 4 mm intervals. Also, as a comparison, (N) Do not irradiate plasma spots only with groove forming processing (O) Do not perform groove forming processing and 4 mm in the direction perpendicular to the rolling direction A material was also prepared that was subjected to plasma point irradiation only at intervals.

From the product coil thus obtained, a sample was sampled in the same manner as in Example 1 and the magnetic characteristics were measured. The results are shown in Table 3.

[Table 3] From Table 3, it was found that the material having the high dislocation density portion at the position not overlapping the groove had a larger reduction range of the iron loss than the comparative example.

Example 3 C: 0.073%, Si: 3.3%, Mn: 0.068%, Se: 0.019
%, Al: 0.023%, Sb: 0.023% of a silicon steel slab containing a hot-rolled sheet and a final cold-rolled sheet having a thickness of 0.23 mm through two cold-rolling steps with an intermediate annealing by a predetermined method. did. Then, resist ink was applied to this cold-rolled plate, leaving a non-application portion corresponding to the shape of the linear groove, and masking was performed. Here, the shape of the non-coated part is 10 ° with respect to the plate width direction.
The width was set to be a straight line with a width of 0.20 mm. The non-coated portion consisting of such a straight line was left at every 3 mm gap in the rolling direction. After that, by electrolytic etching treatment using a NaCl bath to form a linear groove with a depth of 0.020 mm, the resist agent was removed, decarburization annealing and finish annealing were performed, baking was performed, and a tension coating was applied, After baking, it was annealed at 850 ° C. for 3 hours to obtain a product plate with linear grooves. Further, a high dislocation density region was locally introduced into this product plate according to the following conditions (a) to (c).

Note (a) A plasma jet is formed on one side of all linear grooves formed at 3 mm intervals so that there is no gap between the linear grooves and it does not overlap the linear grooves, that is, at a 3 mm gap. Irradiation [Fig. 2
(b) Reference] (b) On both sides of all linear grooves formed at 3 mm intervals, without leaving a gap between them and not overlapping with the linear grooves,
Irradiation with a plasma jet [Refer to Fig. 2 (f)] (c) Every other linear groove formed at 3 mm intervals so that there is no gap on one side of the linear groove and it does not overlap with the linear groove. , Plasma jet irradiation [See Fig. 2 (b)] As a comparison, (d) Product plate with linear grooves formed at 3 mm intervals without plasma jet irradiation processing (e) Plasma jet irradiation processing at 3 mm intervals Applied product plate (f) A product plate was also prepared on which neither linear groove formation nor plasma jet irradiation treatment was applied.

From the product coil thus obtained, a sample was sampled in the same manner as in Example 1 and the magnetic characteristics were measured. The results are shown in Table 4.

[0049]

[Table 4] From Table 4, it is clear that the product sheet in which the linear high dislocation density region is formed in the region adjacent to the linear groove has a lower iron loss than the comparative material.

Example 4 C: 0.070%, Si: 3.4%, Mn: 0.068%, Se: 0.019
%, Al: 0.023%, Sb: 0.025% silicon steel slab containing 0.23mm thick final cold-rolled sheet after hot rolling and two intermediate cold rolling steps with intermediate annealing. did. Next, the resist ink was applied and masking was performed, leaving the non-application portion corresponding to the shape of the linear groove introduced into this steel plate. Here, the shape of the non-application portion was a linear shape having a width of 0.30 mm and extending at an angle of 10 ° with respect to the plate width direction.
The non-coated part consisting of such straight lines has a gap of 5 mm in the rolling direction.
Left for each. Next, after a linear groove having a depth of 0.020 mm was formed by electrolytic etching treatment using a NaCl bath, the resist material was removed, and decarburization annealing and finish annealing were performed. Then, after applying tension coating and baking, 850 ℃
It was annealed for 3 hours to obtain a product plate with linear grooves. Further, a high dislocation density region was locally introduced into this product plate according to the following conditions (g) to (k).

Note (g) Irradiating a plasma jet at 5 mm intervals with a 0.20 mm gap between the linear grooves on one side of all the linear grooves formed at 5 mm intervals [see FIG. 2 (a)]. ] (H) Irradiate a plasma jet on one side of all linear grooves formed at 5 mm intervals so that there is no gap between them and they do not overlap the linear grooves (see Fig. 2 (b)) ( i) Irradiate a plasma jet on one side of all linear grooves formed at 5 mm intervals so that the bottom surface of the groove overlaps with a width of 0.20 mm [see Fig. 2 (d)] (j) All adjacent linear grooves formed at 5 mm intervals Irradiating a plasma jet in the middle of a pair of linear grooves [See Fig. 2 (e)] As a comparison, (k) Irradiating a plasma jet directly under all linear grooves formed at 5 mm intervals (l) Irradiating a plasma jet A product was also prepared which was not processed and was subjected to a process of forming linear grooves at 5 mm intervals. From these 6 samples,
Table 5 shows the results of cutting the Epstein test piece so that its longitudinal direction coincides with the rolling direction and measuring the respective magnetic properties.

Specimens were sampled from the product coil thus obtained in the same manner as in Example 1 and the magnetic characteristics were measured. The results are shown in Table 5.

[0053]

[Table 5] From Table 5, it is clear that the product sheet in which the linear high dislocation density region is formed in the region adjacent to the linear groove has a lower iron loss than the comparative material.

[0054]

EFFECTS OF THE INVENTION The steel sheet of the present invention has a linear groove extending in a direction intersecting with the rolling direction and a linear high dislocation density region in a predetermined arrangement on the surface thereof, so that it is extremely lower than the conventional material. Since it shows iron loss, it greatly contributes to the improvement of the efficiency of transformers, especially core transformers.

[Brief description of drawings]

FIG. 1 is a diagram showing introduction positions of grooves and high dislocation density regions.

FIG. 2 is a diagram showing introduction positions of grooves and high dislocation density regions.

FIG. 3 is a diagram showing a relationship between groove width and iron loss W _17/50 .

FIG. 4 is a diagram showing the relationship between groove depth and iron loss W _17/50 .

FIG. 5 is a diagram showing a relationship between a groove inclination angle and iron loss W _17/50 .

FIG. 6 is a diagram showing a relationship between groove spacing and iron loss W _17/50 .

FIG. 7 is a diagram showing the relationship between the width of the high dislocation density region and the iron loss W _17/50 when the groove and the high dislocation density region are present at the same time.

FIG. 8 is a graph showing the relationship between the depth of the high dislocation density region and the iron loss W _17/50 when the groove and the high dislocation density region are present at the same time.

FIG. 9 is a diagram showing a relationship between an interval between high dislocation density regions and iron loss W _17/50 when a groove and a high dislocation density region are present at the same time.

FIG. 10 is a diagram showing the relationship between the inclination of the high dislocation density region and the iron loss W _17/50 when the groove and the high dislocation density region are present at the same time.

Front Page Continuation (72) Inventor Keiji Sato 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Technical Research Division, Kawasaki Steel Co., Ltd. Technology Research Division, Inc.

Claims (3)

[Claims] 1. A surface of a finish-annealed grain-oriented silicon steel sheet has a large number of linear grooves extending in a direction intersecting with the rolling direction and linear high dislocation density regions at intervals in the rolling direction, The linear groove and the high dislocation density region are arranged such that at least a part of the high dislocation density region is outside the formation region of the linear groove.
A unidirectional electrical steel sheet with low iron loss, which is introduced on the surface of a steel sheet. 2. The grain-oriented electrical steel sheet according to claim 1, wherein the inclination of the linear groove and the linear high dislocation density region with respect to the direction orthogonal to the rolling direction is within 30 °. 3. The linear groove has a width of 0.03 to 0.30 mm and a depth of 0.01.
~ 0.07mm, high dislocation density range 0.03 ~ 1mm width and 0.01 depth
The grain-oriented electrical steel sheet according to claim 1, having a size of at least mm.