DE3226640A1 - GRAIN-ORIENTED ELECTRO-STEEL SHEET WITH LOW WATER LOSS AND METHOD AND DEVICE FOR THE PRODUCTION THEREOF - Google Patents

Description

The present invention relates to grain oriented, low wattage electromagnetic steel sheets and a method and an apparatus for their manufacture.

Grain oriented electromagnetic steel sheets (hereinafter referred to as electrical steel sheets) have crystal grains where the direction of easy magnetization, i.e. the / 1007 axis, is parallel to the rolling direction; the Grain orientation of grain-oriented electrical steel sheets results from the final annealing, in which the secondary recrystallization takes place. Conventionally produced, grain-oriented electrical steel sheets have either a single orientation in which the (110) plane and the / Ioo_7 axis of the crystal grains are parallel to the sheet surface or to the direction of rolling, or a double orientation in which the (100) plane and the / 5oi7 axis the crystal grains are parallel to the sheet surface or to the rolling direction.

Attempts have been made to determine the degree of orientation of

oriented electrical steel sheets to increase, so that the grain orientation of all crystals of the sheet with easier Orientation is apparently ideal or (100) - / Ö0l7, so that when the degree of orientation is increased, essentially the excitation characteristic is increased and the watt losses are reduced. As a result, you can now Grain-oriented electrical steel sheets are manufactured industrially, which have a magnetic flux density of 1.7 Tesla show at 0.3 mm sheet thickness. To further reduce the watt losses, procedures must be used that differ from that used to increase the degree of orientation of a grain-oriented electrical steel sheet. this

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means that it is difficult to measure the watt losses only to be further reduced by increasing the degree of orientation; the reasons for this are explained below. The watt losses of a grain-oriented electrical steel sheet depend on the excitation characteristics and the Grain size. In particular, the watt losses of a grain-oriented electrical steel sheet can be increased by increasing the excitation character eristika and can be reduced by reducing the grain size. The excitation characteristics of a grain-oriented Electrical steel sheets are usually enlarged by increasing the grain size. The grain size of a grain oriented Electrical steel sheet is usually increased by increasing the degree of orientation; at this increase, however, results at the same time as a factor which disadvantageously increases the watt losses, and a factor which advantageously reduces watt loss, thereby increasing the excitation characteristic.

It is known that the watt losses of a grain-oriented electrical steel sheet can be increased by the action of tensile forces the sheet surface can be reduced. An industrial process for applying tensile forces to the sheet metal surface involves applying an insulating film to the steel sheet. Reducing watt losses through However, application of the insulating film is limited because of the impact on the sheet metal surface through the insulating film exercised is also limited. The lowest watt losses that can be expected from the foregoing industrial Methods for applying a tensile force are approximately 1.05 W / kg at 50 Hz.

It is also known to reduce the watt loss of a grain oriented electrical steel sheet by mirror polishing, e.g.

by chemical or electrolytic polishing, and

possibly subsequent application of an insulating film to the steel sheet. This method

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However, to reduce the watt loss is therefore disadvantageous because the watt loss depends on the smoothness of the polished steel sheets vary greatly. The watt losses of a grain-oriented electrical steel sheet with applied insulating film therefore also vary greatly as the properties of the insulating film vary the smoothness of the polished steel sheet can be changed.

In JP-OS 35079/75 has been proposed the surface corrugating or scratching a grain-oriented electrical steel sheet with a knife or an abrasive material, to reduce watt losses. However, the corrugation or scratching inevitably leads to the formation of Cracks on the grain oriented electrical steel sheet, and hence unevenness around these cracks. Hence will not only the feel factor of the laminated portions of a grain oriented electrical steel sheet by the above Irregularity is drastically reduced, but magnetostriction of the steel sheet is also increased drastically by the corrugation or scratching. Further be Burrs formed at both ends of the cracks during the scratching process, which protrude from the sheet metal surface, and when sections of grain oriented electrical steel sheet are laminated, the burrs penetrate at these sections through the on. insulating film applied through the adjacent portion. There are suggestions to eliminate the disadvantages resulting from the grooves or scoring and to reduce the watt losses below the fourth, which can be achieved by increasing the degree of orientation receives.

In one of these proposals (JP-OS 157 OI6 / 78) is a very small elongation in a grain-oriented electrical steel sheet produced by rolling or by being

lets a small ball or disk rotate over the sheet steel with constant pressure. At the proposal according to

-ιοί JP-OS 4j5 115/79 is a very small stretch in one Highly polished, grain-oriented electrical steel sheet produced by rolling or by making a small one Lets the ball or disk rotate over the highly polished sheet steel. With these suggestions the disadvantages would be eliminated due to the formation of grooves or cracks and further reduced watt losses. However, it results from from an economic point of view further problems to be solved. One of these problems is that the steel sheet either held stationary or transported while the minor stretch is being created, as a Small ball or disk rolled over a grain-oriented electrical steel sheet to generate the slight expansion or must be rotated. Furthermore, it is difficult to increase the production of steel sheets because the relative Rolling or rotating speed of a small ball or disk over the grain-oriented electrical steel sheet is limited.

In contrast, the invention is based on the object to specify a method by which the watt loss of a grain-oriented electrical steel sheet is reduced, in which a very weak strain is formed in the steel sheet

which is so that cracks, cracks, gaps or cracks, / the filling

reduce the factor of the laminated sections of the steel sheet, do not occur and the productivity of the steel sheets is increased.

According to the invention, a device for through-

lead of the method according to the invention are given.

According to a further sub-task, a grain-oriented electrical steel sheet is to be specified which, due to the elongation generated therein has low wattage losses and

also has good surface properties, so that the space factor of the laminated portions is high.

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The object of the invention is achieved by the claims.

The invention is explained in more detail below with reference to the drawing. Show it:

Fig. 1 is a view of an embodiment of the invention Contraption,

Pig. Fig. 2 is a schematic illustration for explaining how steel particles, essentially

straight, selected section of the grain-oriented electrical steel sheet applied according to the invention will,

FIG. 5 shows a representation similar to FIG. 2, but with the Application of the steel particles is interrupted, Fig. 4 essentially linear selected sections

a grain-oriented electrical steel sheet, with strains generated by the application of particles will,

Fig..5 is a view of an embodiment of a device according to the invention,

6 shows a cross section of the device according to FIG. 5, 7 shows a view of a further embodiment of a device according to the invention, wherein the particle application can take place after heat smoothing,

8 shows a cross section from the side of an embodiment of the device according to the invention,

FIG. 9 is a view similar to FIG. 8,

Fig. 10 is a cross-section from the front of an embodiment

the device according to the invention,

11 shows a diagram for the magnetic flux density (Bg) and the watt loss (Vi ₁₇ λ-q) due to the particle application and

Figure 12 is a block diagram of an embodiment of the er-35

inventive device with a computer circuit for the watt losses.

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1 to 3 is a grain-oriented electrical steel sheet or strip 1, which is hereinafter referred to as steel sheet 1 for the sake of simplicity. This sheet steel 1 contains no more than 4.0 $ silicon and, as stated above, was finish-annealed, which changes the grain orientation revealed.

When the steel sheet 1 is charged with particles, it may be provided with an unillustrated insulating film be. The insulating film, not shown, may be a secondary insulating film made of a phosphate compound or an organic compound and can be from 1 to 5 μm thick. Furthermore, the particle application can after

the heat smoothing.
15th

The steel sheet 1 is indicated by the arrow (Fig. 1) Direction transported along a belt plane. Above the steel sheet is a stationary plate 3 arranged so that a predetermined distance is maintained between this and the steel sheet 1. A sliding one Plate 4 is placed on the stationary plate 3 and via a piston rod with a drive 5, for example a hydraulic or pneumatic cylinder. tied together. The sliding plate 4 therefore moves through

the drive 5 back and forth, with the stationary

Plate 3 remains in contact. The stationary plate 3 and the Slidable plate 4 are each provided with a slot 2, the length of which is slightly greater than the width of the steel sheet 1. Only if during the back and forth movement 30

of the displaceable plate 4, the two slots 2 are aligned with one another, is the particle delivery device 10 (Fig. 3), which is directed to the slot 2 of the sliding plate 4, operated so that particles, for example

Steel balls or drops 7 on the essentially linea-35

Ren selected sections of the steel sheet 1 (Fig. 2) released will. There. several such steel beams 7

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the selected sections collapse, several very • small point-like impressions are formed, and in these stretch is created in small dotted areas. Furthermore, since the impact pattern is defined by the linear shape of the Slots 2 is determined, which extends in the width direction of the Steel sheet 1 extend, the small dotted areas also have a linear shape.

As pressed or ejected particles, not only steel particles but also other metal particles, organic resin particles, ceramic particles and particles of plant material can be used. The particles should have a substantially spherical shape. The delivery of the particles can be carried out together with the injection of a fluid, for example a gas, e.g. air, or a gas-liquid mixture, with the help of at least one nozzle.

Steel particles are known to be used for descaling rolled steel products. The impact of the Stanion

particles according to the invention can, for example, be smaller than during descaling, but the impact force should with which the surface of the steel sheet 1 is easily hit, be large enough to reduce the watt loss.

The impact force can optionally depending on the

Amount of impact, the size, the material and the hardness of the Particles and the width of the slots 2 as well as the tensile force exerted on the steel sheet 1, that is transported. As with any method of

Creating a stretch in a grain-oriented electrical 30

In sheet steel, a very strong expansion does not lead to a reduction but to an increase in the losses.

In FIG. K , several selected sections 8 of a steel sheet 1 are linear, essentially perpendicular to the rolling direction of the steel sheet 1 and parallel to one another. Each of the selected sections 8 is a solid line

or curve. Furthermore, each selected section 8 can be a discontinuous straight line 8a or curve 8b. The width S of the selected sections 8 is preferably from 0.1 to 0.5 ram. In Fig. 4 are the point-like indentations provided with the reference number 11. The surface area of the point-like indentations 11 is significantly smaller than that of the selected sections 8. The punctiform indentations 11 have a diameter of 6o to 8o µm and 3 to 5 µm in depth. It is important that the dimension of the punctiform Indentations 11 is small and narrow, so that the watt losses of the steel sheet 1 are reduced. The sheet steel 1 has no burrs around the punctiform indentations 11, since these are caused by the bombardment with the steel particles are formed (Fig. 2 and j5). The areas of the steel sheet 1 in which 'tensile stresses are generated, are essentially linear. To be precise, these areas are defined by several small punctiform areas, which are arranged essentially linearly. Even though

the selected sections 8 linearly and substantially 20

are perpendicular to the rolling direction, selected sections can also have other patterns that are irradiated with the particles will. For example, discontinuous or continuous sections that extend in a straight line are conceivable

or do not extend in a straight line in the rolling direction and with the 25th

Particles can be irradiated.

When an unillustrated insulating film is applied to the steel sheet 1 before the particles are irradiated has been, damage the punctiform indentations 11

not seriously the insulating film. In addition, a considerable reduction in watt losses is obtained, for example 0.08 W / kg for W ₁₇ y ₅₀ , while at the same time the fill factor of the laminated sections of the steel sheet 1 is not noticeably reduced by the punctiform indentations 11

will.

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The distance between the selected sections 8 (linear expansion distance p) can be, for example, 3 to 10 mm. This expansion distance ρ can be adjusted by adjusting the speed of the reciprocating sliding plate 4 will.

Although in the device according to FIGS. 1 to 3 a slot 2 is provided in the stationary plate 3 and in the sliding plate 4, a plurality of slots in each of the two Plates 3 and 4 may be provided. About the linear expansion distance To reduce ρ, the transport speed of the steel sheet 1, the speed of the reciprocating, sliding plate 4 or the number of seat braids 2 can be increased. Increasing the number of slots 2 to decrease of the linear expansion distance ρ is more advantageous than increasing the speed of the reciprocating Plate 4, as this speed is limited by the construction of the sliding plate 4 and the drive 5 is.

According to FIGS. 5 and 6, a device according to the invention a rotatable drum 9, the peripheral speed is synchronous with the transport speed of the steel sheet 1. On the cylinder jacket 9a of the drum 9 slots 2 are formed, the slot spacing corresponding to the linear expansion spacing ρ. There are two institutions provided for ejecting the particles, e.g. two impellers or fan wheels 10, with one impeller next to each the two lateral ends of the drum 9 is arranged.

The two running wheels 10 fling the steel particles 7 through openings 9b in the two lateral ends and through Slots 2 of the drum 9 on the selected sections (not shown in Fig. 6). The one shown in Figs Device can be used for treating a steel sheet

be used, which at high conveying speed,

for example 100 m / min or from 200 to 1000 m / min, trans- ly

is ported.

In the embodiment shown in FIG. 7, the running wheels 10 are arranged inside the rotatable drum 9. 5

Although two wheels 10 are provided in each of the above two Ausführungsforraen, it is in the frame the invention also possible, just one impeller or more to be provided as two impellers, but it must be ensured that the particles on the slots of the rotatable Drum 9 are directed.

The device according to the invention is particularly suitable for practical use, has a very simple design and relatively inexpensive in terms of installation costs. Since the steel particles 7 can be reused by a recovery system (not shown), the operating costs are in the method according to the invention and in the device according to the invention is very low.

8 and 9, the steel sheet 1 with the help of a Conveyors, pinch rollers or other transport devices, not shown, in the areas indicated by the arrow in FIGS. and 9 indicated direction and along a belt running plane transported. Below the belt running level of the steel belt 1, an endless conveyor I5 with slots 2 is arranged, the to the steel sheet 1 indicates .. The slots 2 are arranged at a predetermined distance from one another and extend in the width direction of the steel sheet 1, i.e. perpendicular to the

Drawing plane. The steel sheet 1 can be arranged directly on the endless conveyor 13. It is also at the specified distance from the steel sheet Γ a device for dispensing the particles is arranged.

On the particles, i.e. the steel particles 7 (Fig. 8), 7a and 7b (Fig. 9) and 7c and 7d (Fig. 10), acts with the help of

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Impellers or impellers l4, I4a and l4b or 14c and I4d a centrifugal force so that the steel particles 7, 7a, 7b, 7c and 7d hit a surface of the steel sheet 1, i. onto the underside of the steel sheet 1. Due to the in the sections of the endless conveyor 13 formed slots 2, the steel particles 7, 7a and 7b pass through while the other portions of the endless conveyor 13 shield the steel particles 7, 7a and 7b. As a result, the steel particles 7, 7a, 7b, 7c and 7d are not on the entire underside of the steel sheet thrown, but only on those sections of the underside of the steel sheet 1 to which the slots 2 are directed are. Since the slots 2 extend in the width direction of the steel sheet 1, the selected portions are in essentially straight forward. Furthermore, since several steel particles 7, 7a, 7b, 7c and 7d impinge on selected sections, several very small point-like indentations are also formed, with expansion stresses in form the very small point-shaped areas.

The endless conveyor 13 is driven by rollers and tensed by this if necessary.

The steel particles 7 (FIG. 8) are thrown vertically upwards through the slots 2 ″ onto the steel sheet 1. The steel particles 7a and 7b (Fig. 9) and 7c and 7d (Fig. 10) are with the help of the impellers 14a and 14b (Fig. '9) or the. Running wheels 4c and 4d (Fig. 10) not thrown vertically upwards but in a slightly inclined direction. The impeller 14 as well as the impellers l4a and 14b and 14c and I4d are arranged inside the housing 12 of a fan system, but can also be outside of the housing 12 can be arranged.

The steel particles 7, 7a, 7b, 7c and 7d that are on the endless conveyor 13 or the steel sheet 1 will hit

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collected in the lower part of the housing 12 and with the help of a collection and circulation device (not shown) for reuse returned.

FIG. 12 shows a block diagram of a device according to the invention with a watt loss computing and control circuit. The power supplies 21a and 21b have an oscillator with mains frequency and excite the excitation coils 235a and 25b of detectors 22a and 22b, respectively. 10

The detectors 22a and 22b have coils 24a and 24b, respectively Measuring the positive magnetic density of the steel sheet 1 and coils 25a or 25b for applying a magnetic field, whose strength corresponds to the given measurement condition.

An integrator 27 integrates the magnetic field strength over time, and the voltage generated due to the magnetic flux density is amplified by the preamplifier x 28; the integrated voltage, which is generated by the magnetic field strength, is then multiplied by the output voltage of the preamplifier 28 in a multiplier 29. The output signal of the multiplier 29 is divided by the output signal of the signal generator 3 ¹ to adjust the cross-sectional area, so that the watt losses of the steel sheet 1 obtained before the particle bombardment. The microcomputer 36 subtracts the watt loss obtained from a watt loss reference signal and generates the output signal 2. The calculating circuit for the watt losses consists of the integrator 27, the preamplifier 28, the multiplier 29, the divider 30, the signal generator jU » the integrator 32, the The rectifier 33, the divider 34 and the microcomputer 36. The output signal 2 of the microcomputer 36 is sent to the device 26, ie the strain generator.

The integrator 32 integrates an induction voltage Coil 24a for measuring magnetic flux density, and the

integrated induction voltage is generated by the rectifier 33 rectified. The positive magnetic density of the steel sheet 1 is obtained by the divider 34, which is the output signal of the rectifier 33 is divided by the output signal of the signal generator 31 to determine the cross-sectional area.

The divider 3 ^ and the reference voltage generator 35 bil the one negative feedback loop for regulating the positive magnetic density and the power supplies 21a and 21b.

Any device for firing can be used as the strain generator 26 Selected sections of the steel sheet 1 with particles are used, in which case in the point-like areas internal stresses are generated in the substantially linear selected sections. A detector 22a is open the belt pass plane of the steel sheet 1 in the direction of passage arranged in front of the strain generator 26, while the other detector 22b on the strip running plane of the steel sheet 1 arranged behind the expansion generator 26 in the direction of passage is.

The microcomputer 36 generates a signal to periodically change over the switches SW. and SW ₂ and controls the expansion

voltage generator 26 as follows: After the microcomputer 36 has received the output signal of the divider 30, will _he d Watt loss of the steel sheet 1 after the particle bombardment of the watt loss of particle bombardment subtracted, so as to obtain the iron loss difference; if this difference indicates a decrease in watt loss, the applied stretching force is maintained or adjusted so that this difference continues to increase; however, if the watt loss difference indicates an increase in watt loss, the force causing the elongation is adjusted so that the watt losses decrease. The strain generator 26 or the strain energy can thereby be

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can be controlled by the particle bombardment speed adjusts. The particle bombardment speed is preferably from 25 to 30 m / sec when the magnetic flux density (Bg) of the steel sheet 1 is about 1.95 T, and preferably from 20 to 25 m / sec when the magnetic flux density (Bn) of the steel sheet 1 is about 1.92T. The output signal 3 of the microcomputer j6 is printed out in an appropriate format, and the watt loss before and after the particle bombardment and the transport length of the steel sheet 1 therein Print format is used as information for the further treatment of the steel sheet 1.

example

The particle bombardment takes place with the aid of the device according to Fig. 2.

The steel sheet 1 is 0.1J0 mm thick and has the following magnetic properties before particle bombardment:

^w 17 / 5O ^{= 1} ^ ^{00 to lil0 W // ks}
B ₈ = 1.93 to 1.96 T

^W 17/50 ^{is the watt loss at} 1j7T magnetic flux density and at 50 Hz.
25th

The conditions for particle bombardment are as follows:

Type of particle:

• Steel particles 7
Nominal diameter of the steel particles "J:

0.3 mm
Actual diameter of the steel particles 7:

from 0.1 to 0.4 mm
Amount of fire:
of 3 Ms 30. kg / itiin / m ²

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Fire speed (speed of steel particles 7):

from 12 to 52 m / sec.

Linear expansion distance ρ (distance between the slots 2):

. IO mm
Width of the slots 2:

about 0.7mm

Transport speed of the steel sheet 1: from 0.3 to 3.0 m / min

The values for W ₁₇ Z ₅₀ (measurement on a single sheet) and for Bg are given in FIG. 11. According to FIG. 11, with a suitable choice of the bombardment speed, the watt loss W ₁₇ ^ _{50 is} reduced in comparison to the watt loss W ₁ ^ ₅₀ before the particle bombardment, so that a very low watt loss is obtained. Bg is only slightly reduced at a firing speed at which a reduction in the watt loss W ₁₇ / ^ _{0 is obtained.} Such a small reduction in the Bg value leads to practically no problems.

In general, the following also applies: According to the invention, this can Grain oriented electromagnetic steel sheet containing 4.0% or less silicon and has preferably been finish-annealed to to achieve the grain orientation. The insulating film optionally applied on the electromagnetic steel sheet may be a secondary insulating film made of a phosphate or an organic compound, e.g., 1 to 5 µm Be fat. Particle bombardment is preferably carried out after heat flattening. According to the invention, the particles can either alone or together with a fluid, for example with air as a gas-fluid mixture, delivered with the help of a nozzle

will.
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Claims (1)

VOSSlUS ■ VOSSIUS'-iWCHN-Ep'-HeUNEMANN · RAUH "PaYentanwälte SIEBERTSTRASSE 4- ■ 8OOO MUNICH 86 · PHONE: (O89) 4-7 4O 75 CABLE: BENZOLPATENT MÖNCHEN -TELEX B-29 45 3 VOPAT D uZ: S 016 (He / ko) ₁₆ . _July . ₁₉₈₂ Case: NSC-5536-DE NIPPON STEEL CORPORATION Tokyo, Japan
10 . "Grain-oriented electrical steel sheet with low wattage losses as well as the method and device for its manufacture Claims - Ι ·. Process for producing a grain-oriented electromagnetic Sheet steel with low watt losses, characterized in that after the grain Orientation leading finish annealing of the steel sheet (1) essentially linear, selected sections (8) of the Steel sheet (1) are bombarded with particles (7,7a, 7b, 7c, 7d), in order to generate elongations in the punctiform areas of the selected sections (8). - 2. The method according to claim 1, characterized in that metal particles are used as particles (7,7a, 7b, 7c, 7d). 3 * Method according to claim 1, characterized in that organic resin particles were used as particles (7 * 7a, 7b, 7c> 7d) will. L J 4. The method according to any one of claims 1 to 3, characterized in that that the substantially linear, selected sections (8) of the steel sheet (1) parallel to one another are. 5. The method according to claim 4, characterized in that each of the essentially linear, selected sections (8,8b) of the grain-oriented electrical steel sheet (1) is formed by a continuous line or curve. 6. The method according to claim 4, characterized in that each of the substantially linear, selected sections (Sa) of the grain-oriented electrical steel sheet (1) is a discontinuous line or curve. 7 · Device for the production of grain-oriented, electromagnetic Steel sheets (.1) with low watt loss, characterized by '· (a) a stationary plate (3) with at least one slot (2) and (b) a reciprocating, slidable plate (4) in contact with the stationary plate (3) and has a slot (2) which coincides with the slot or slots (2) of the stationary plate. (3) to cover is achievable, and through (c) at least one device facing the stationary plate (3) (lo) to deliver particles. 8. Apparatus according to claim 7 * characterized in that that the device (10) is a fan or a nozzle. 9. Device for producing grain-oriented, electromagnetic steel sheet (1) with low watt losses, characterized by L -1 ~ ι (a) a rotatable drum (9) with at least one slot (2) on its cylinder jacket and through (b) at least one device (10) for dispensing particles, which is arranged inside or outside the rotatable drum (9). 10. Apparatus according to claim 9, characterized in that at least one device (10) is a fan or a nozzle. Hi device for bombarding essentially linear, selected sections of a grain oriented electromagnetic steel sheet with particles in order in the punctiform areas of the selected sections to generate strains, characterized by (A) an endless conveyor (13) with slots (2), which are in predetermined Are arranged at a distance from each other and extend in the width direction of the electrical steel sheet (1), wherein the endless conveyor (13) faces the electrical steel sheet (1) and is movable at one speed that is synchronous with the transport speed of the Electrical steel sheet.es (1) is, and through (b) a device (I4, "l4a to d) for delivering particles (7 * 7a to &)» which is arranged at a predetermined distance from the endless conveyor (13). 12. The apparatus according to claim 11, characterized in that the means for dispensing the particles outside or 30th is arranged within the closed loop of the endless conveyor (13). IJ). Device according to claim 11 or 12, characterized in that the endless conveyor below the grain 35 oriented electrical steel sheet (1) is arranged so that the Particles to prevent clogging of the slots L J _Γ :: ": I: ''':":.·' 32266Λ0 to be handed in at the top. 14. Apparatus according to claim 11 or 12, characterized in that the endless conveyor (13) above the grain-oriented Electrical steel sheet (1) is arranged, wherein to prevent clogging of the slots of the endless conveyor is preferably arranged inclined and the electrical steel sheet is transported in an inclined direction. 15. Apparatus for producing grain-oriented, electromagnetic steel sheet (1) with low watt loss due to the selective action of strain on the surface of the electrical steel sheet (1), characterized by (A) a device (I4, 14a to d) for dispensing particles on substantially linear selected sections (8) of the grain-oriented electromagnetic steel sheet (1), so that in the point-like areas of the essentially linear, selected sections (8) a stretch is created, (b) a pair of measuring devices (24a, 24b) for measuring watt losses of the electrical steel sheet (1) in the direction of passage of the steel sheet in front of or behind the bombardment with particles (7.7a to d) and through (c) a watt loss calculator circuit (27 to 30,32,33) for calculating the difference in watt loss due to the Particle bombardment, comparing the difference to a reference watt loss and controlling the on the substantially linear, selected sections (8) - the strain energy, the computing circuit with the pair of measuring devices (24a, 24b) is connected. 16. Apparatus for producing grain-oriented, electromagnetic steel sheet (1) with low watt loss by the selective action of an expansion on the surface of the electrical steel sheet (1), characterized by L J r "' O" U :''.-. ::. 322664O _n -V- (A) a device (14, 14a to d) for dispensing particles on substantially linear selected sections (8) of the grain-oriented electromagnetic steel sheet (1), so that in the point-like areas of the essentially linear, selected sections (8) a stretch is created, (b) a pair of measuring devices for measuring the magnetic Plus density on the strip running plane of the grain-oriented, electromagnetic steel sheet (1) in the direction of travel of the steel sheet are arranged in front of or behind the device for dispensing the particles, (c) a pair of devices for applying a magnetic field, these two devices on the plane of tape travel of the grain-oriented electrical steel sheet in front of or behind the device, viewed in its direction of passage are arranged for dispensing the particles, and by "" ■■> -—, _ (d) a watt loss computing circuit for computing the difference in watt loss due to particle bombardment, Compare the difference to a reference watt loss and control that on the substantially linear ones selected Sections applied strain energy, the computing circuit with the pair of measuring devices for measuring the positive magnetic density and the pair of measuring devices for measuring the magnetic field strength connected is. 17. The device according to claim I5, characterized by a pair of devices (25a, 25b) for applying a magnetic field strength, the pair being oriented on the pass plane of the grain electromagnetic steel sheet (1) seen in the direction of passage in front of or behind the device (14, 14a to d) is arranged for dispensing the particles. 18. Device according to one of claims 15 to I7, characterized by an arithmetic circuit for comparison L ■ · J the magnetic flux density of the grain oriented electromagnetic steel sheet with a predetermined reference magnetic flux density and for controlling the range of strain energy.
5 19 · Method and device according to one of claims 1 to 18, characterized in that as particles for bombarding the grain-oriented, electromagnetic steel sheet Steel particles, particles of other metal, particles of organic resin, particles of ceramic or particles can be used from plant material. 20. The method and device according to any one of claims 1 to 19, characterized in that the particles are essentially are spherical. 21. Grain oriented, low watt loss electromagnetic steel sheet, being essentially linear, selected Sections (8) of the steel sheet (1) have punctiform indentations (11) which are formed by particle bombardment are, so that due to the punctiform indentations (11) expansions result. 22. Grain oriented, low watt loss electromagnetic steel sheet, being essentially linear, selected Sections (8) of an insulating film applied to the grain-oriented electromagnetic steel sheet is, has punctiform indentations (11) by particle bombardment, with the punctiform indentations (11) Strains are generated in the grain-oriented electromagnetic steel sheet. 23. Grain-oriented, electromagnetic steel sheet according to claim 21 or 22, characterized in that the diameter of the point-like indentations (11) are from about 60 to 80 µm and the depth from about J5 to 5 µm. L J