JPS6173886A - Method and device for producing ultra-low iron loss grain-oriented silicon steel sheet - Google Patents

Abstract

PURPOSE:To reduce effectively the iron loss of a grain oriented silicon steel sheet subjected to finish annealing by applying a specific quantity of impact force to the forsterite film on the surface of said steel sheet to break down the film and forming linearly the drop-out region across the rolling direction. CONSTITUTION:A silicic steel slab (about 2.4-4.0% Si) is subjected to a prescribed treatment to form the silicon steel sheet subjected to the finish annealing. The impact force controlled in stroke toward the surface of the steel sheet is gradually applied to the foresterite film formed on the surface of such steel sheet by the top end of an oscillating body forced to make forward and backward motion at >=5X10<-6>kg.m/s (the upper limit is 1X10<-1>kg.m/s) momentum to break down the film without forming recesses to the surface of the steel sheet base-rion. The drop-out region is formed linearly across the rolling direction of the steel sheet. The width of the drop-out region is preferably about 0.1-0.4mm and the space of the drop-out region is preferably about 2.0-10.0mm. The steel sheet which is free from the deterioration in the space factor and the iron loss in the laminating stage is thus easily and efficiently produced.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for producing grain-oriented silicon steel sheets with low core loss and an apparatus directly used for carrying out the method, and particularly relates to a method for manufacturing a grain-oriented silicon steel sheet with low core loss, and in particular to a method for manufacturing a grain-oriented silicon steel sheet with low iron loss. The purpose is to improve magnetic properties by forming a .

Grain-oriented silicon steel sheets are mainly used as iron cores for transformers and other electrical equipment, and their magnetization properties are excellent.
In particular, low iron loss (represented by W17150) is required.

For this purpose, firstly, the secondary recrystallized grains in the steel sheet (001
＞It is necessary to highly align grain orientation in the rolling direction,
Secondly, it is necessary to reduce as much as possible the impurities and precipitates present in the final steel product. The iron loss value of grain-oriented silicon steel sheets manufactured with such consideration has been improved over the years due to many improvement efforts to date, and recently, the value of W17150 has increased to 1 for products with plate thicknesses of O and aO. ,05W
/IC9 low core loss was obtained.

However, after the energy crisis a few years ago, the trend for electrical equipment with lower power loss became even stronger, and unidirectional silicon steel sheets with significantly lower core loss were required as core materials for these devices. It looks like this.

By the way, methods to reduce the iron loss of grain-oriented silicon steel sheets include increasing the Si content, reducing the thickness of the product sheet, making the secondary recrystallized grains finer, reducing the impurity content, and (110) ( Metallurgical methods are generally known, such as aligning the secondary recrystallized grains of orientation to a higher degree, but these methods have already reached their limits with current production methods. Further improvement is extremely difficult, and even if some improvement is recognized, the effect of improving iron loss is small compared to the efforts made.

For example, in a method of highly aligning secondary recrystallized grains in the (110)(001) orientation, if the degree of accumulation in the (110)(001) direction is increased as much as possible, the magnetic flux density (magnetization Although the maximum magnetic flux density (represented by B1o at a force of 1000 A/m) improved, the iron loss deteriorated because the secondary recrystallized grains gradually became coarser. This is due to coarsening of secondary recrystallized grains, which widens the spacing between domain walls that form the boundaries of the magnetic domains of the steel sheet, the so-called domain width, and causes an increase in eddy current loss, which deteriorates core loss.

(Prior Art) Various proposals have been made in the past regarding methods for further reducing iron loss beyond the limits of the metallurgical methods listed above.

First, U.S. Patent No. 3,647,575 states that by scratching or strongly rubbing the surface of a grain-oriented silicon steel plate (hereinafter referred to as steel plate) with a knife or a hard substance such as diamond sand, iron loss can be reduced. A method is disclosed. However, with this method, unevenness is formed around the scratches, which significantly deteriorates the space factor when the steel plates are laminated. There was a drawback that leakage caused a perpendicular magnetization component in the steel plates during lamination, which deteriorated iron loss.

Also, Tokuko Showa 58-5! : Publication No. 168 discloses that a spherical rotor or a thin disk is placed in contact with the surface of a copper plate and a load is applied.
A method has been proposed in which a wire is drawn while rotating to give a minute strain to the surface of a single plate. With this method, neither deterioration of the space factor nor deterioration of iron loss during lamination occurs, but it is extremely difficult to control the appropriate depth and width of the recesses due to rotor suppression.

Furthermore, a device that gives such minute distortion was developed by
Although it is disclosed in Japanese Patent No. 410889, the device becomes complicated and it is difficult to use it for manufacturing actual products, and there is also a risk of deterioration of magnetic flux density due to dents.

JP-A-58-16027 discloses that granular materials such as metal grains and synthetic resin grains are projected onto the surface of a grain-oriented silicon steel sheet that has been finish annealed to impart point strain in a linear manner to reduce iron loss. Disclosed is a method and apparatus for lowering. Although this method is relatively simple, it is difficult to control the amount of strain applied, and strong projection deteriorates both iron loss and magnetic flux density.

Japanese Patent Publication No. 57-2252 discloses a method of reducing iron loss by irradiating the surface of a grain-oriented electrical steel sheet with finish annealing to form locally high dislocation density regions in the steel sheet. ing. With this method, it is easy to control the energy density of the laser beam irradiated to locally form high dislocation density regions, there is no deterioration in the space factor, and there is no deterioration in iron loss when stacked. Therefore, it has come to fruition. However, because the laser generator and optical system are large-scale, the number of units installed in the manufacturing process is limited, and a specified high energy density must be provided with a limited number of units installed. The irradiation speed is limited.

Therefore, the laser processing ability of grain-oriented silicon copper plates in factories is low, resulting in a decline in operational efficiency. In order to avoid this interlayer, attempts have been made to increase the number of irradiated beams by using optical means such as multi-focal mirrors, half mirrors, or optical fibers. Not,
These measures are also not effective.

(Problems to be Solved by the Invention) In this invention, in a manufacturing method for reducing iron loss by removing the film of a finish annealed grain-oriented silicon steel sheet, the magnetic flux density, space factor, The purpose of the present invention is to provide a method that does not reduce losses, is easy and simple to implement, and does not cause a decrease in the efficiency of actual operations.

Furthermore, another object of the present invention is to provide an efficient manufacturing apparatus made of M, which is used to carry out the above-mentioned manufacturing method.

(Means for Solving the Problems) The inventors investigated ways to reduce iron loss in the treatment of finish-annealed steel sheets, and as a result, the inventors discovered 177 that reduces the magnetic domain width.
It was newly discovered that J is related to the forsterite coating (hereinafter referred to as coating) on the surface of one plate. That is,
In regions where the coating is missing in the form of points, needle-shaped auxiliary magnetic domains called daggers are generated within the magnetic domain, and when defects in the coating are linear, the width of the magnetic domain tends to be narrower. I found out something.

In this regard, we further investigated the role of the coating and found that, similar to a tension-applied coating, this coating adds tension to the tuning plate and subdivides the magnetic domains. It was also discovered that this subdivision of the magnetic domain width is due to non-uniform elastic strain being imparted to the surface of the steel sheet due to the lack of a coating.

The inventors conducted further research and found that iron loss could be extremely effectively reduced by removing the coating using the force of vibration. In other words, due to the effect of non-uniformity of elastic strain due to coating removal, and the vibration to break the bond between the substrate and coating when removing the coating due to impact force, there is a very slight plasticity on the surface of the substrate where the coating is removed. It was discovered that the effect of the tension on the metal surface caused by this plastic strain and the significant reduction in iron loss was possible.

In addition, the conventional method of applying strain was to form dents on the surface of the steel plate, but dents are not an essential requirement, and rather, in order to maintain magnetic flux density, it is better not to have dents. However, the coating (Mg25iO,) is made of ceramic polycrystalline material, and in order to destroy only the coating without forming a dent in the base metal of the steel plate, it is necessary to use a static method such as pressing. This is not possible with force, and a dynamic force such as an impact force due to vibration is required.
It is expressed as the product 'wLv' of rIL (kg) and its average speed V (rrL/S), and the larger the value of this m'TJ, the more advantageous it is.

Therefore, it is better if m and V are thicker, but the quality M”
If the value is large, it will be difficult to control the vibration stroke, so the quality ′! To increase the frequency of a vibrating body without increasing im. This is because an object of mass m has simple harmonic motion X-1/2 L Sin
When it is vibrating at wt, the frequency is f=ω/2π(H
2), the reciprocating stroke is I (cm), and the period is T
Then, the average motion is as follows, and by increasing the vibration frequency, the amount of motion can be increased without any interruption in the controllability of the vibration stroke. Moreover, since it is possible to reduce the stroke L, this is preferable in terms of side effects, and is especially advantageous in the ultrasonic range, for example.

This invention is derived from the above knowledge.

In other words, one silicon slab is hot-rolled (5), and then the hot-rolled plate is subjected to one or two cold IJU rollings with an intermediate/descent to achieve the final thickness, and then decarburized and In producing a oriented silicon shoulder plate through a series of steps of performing primary recrystallization annealing, then applying a dulling agent mainly composed of MgO to the surface of the steel sheet A, and then final annealing. The forsterite coating on the surface of the finish-annealed steel plate is subjected to a stroke-controlled impact directed toward the plate surface at the tip of the vibrating body by a moving body that is forced to reciprocate at a speed of 9 m/s or more. '7 force is applied successively to proceed with the destruction of the forsterite film without forming a dent on the surface of the SA plate field steel, and to form a defective region of the forsterite film in a linear shape across the rolling direction of the copper plate surface. A method for producing an ultra-low core loss oriented silicon steel sheet.

Further, in carrying out the above manufacturing method, the forsterite coating is removed using the following device.

A vibrating body that is reciprocated by an excavator is placed close to a finish-annealed directional silicon "V" plate, and the vibration stroke of the vibrating body toward the surface of the copper plate at the tip of the vibrating body is controlled. An apparatus for producing an ultra-low iron loss grain-oriented silicon steel sheet, which is equipped with a controller to apply a stroke-controlled impact force to the surface of one sheet.

Further, the manufacturing method of the present invention will be explained in detail.

The feature of this invention is that it is processed into a finish-annealed grain-oriented silicon plate. First, grain-oriented silicon plate A is manufactured in accordance with a conventional method.

The material of this invention is made into a slab (steel billet) by a known method, such as a convertible F1 electric furnace, and then made into a slab (steel billet) by a rough ingot-blooming method or a continuous casting method. The hot rolled sheet using the hot rolled coil obtained by hot rolling preferably has a composition containing about 2.4 to 4.0 parts of Si. This means that Si is 2.0%.
If it is less than 4.0%, iron loss will deteriorate significantly, and if it exceeds 4.0%, cold workability will deteriorate.

As for the other components, any material component of oriented silicon 1:1 plate can be used.

Next, cold rolling is performed to obtain the final colossal plate thickness, but cold I1
One rolling is performed by cold rolling once or twice with intermediate annealing sandwiched in between. At this time, if necessary, uniform annealing of the rolled sheet or warm rolling instead of cold rolling can be performed.

The cold-rolled sheet having the final thickness is subjected to primary recrystallization annealing in an oxidizing atmosphere that allows decarburization or a weakly oxidizing atmosphere that allows subscale formation.

Next, a forsterite film is formed by applying a sintering separation agent containing MgO as the main component to the surface of the plate, followed by secondary recrystallization annealing, high-temperature purification annealing, and final finishing annealing. .

Next, the film on the surface of the finish annealed copper plate is removed linearly.

When removing the film, apply 9 m/s to 5 x 10-6.
From the above, it is preferable that the stroke toward the surface of the steel plate be controlled at its tip by a vibrating body that is forced to reciprocate at a speed of (IXI (1") ~ m/s or more and less than (lxxo-1) m/s in practice). The coating is destroyed by successively applying impact force to prevent the formation of dents on the surface of the grooved plate base steel, thereby forming a coating defect area.The most advantageous shape of the coating defect area is a direction perpendicular to the rolling direction. However, it may also be in an oblique direction or in a sinusoidal shape.

Further, the width of the film-deficient region is preferably 0.1 to 0.4 mm, and the interval between the film-deficient regions is preferably 2.0 to 10.0 mm. Furthermore, if the loading force applied to the steel plate surface is large,
Since there is a risk of forming a dent on the surface of the tunnel plate base iron, the upper limit of the momentum of the vibrating body is (IXI 0-1) turret・m /
It is desirable to suppress it to s.

As a device for applying an impact force by vibration to the surface of a copper plate to remove the coating, for example, the devices shown in FIGS. 1 and 2 may be used. Next, coating removal will be explained with reference to the illustrated device. .

In the figure, reference numeral 1 indicates a finish annealed directional silicon plate (hereinafter referred to as a plate), which is moved, for example, in a direction perpendicular to the plane of the paper.

The tip of the vibrating body 2 is placed close to the surface of the steel plate 1. The vibrating body 2 has a momentum of 5×10 kg・m/
It applies an impact force to the surface of the M plate 1 by reciprocating motion for more than s, and the shape of the tip of the vibrating body 2 that comes into contact with the surface of the steel plate 1 must be determined to match the width of the defect area to be formed in the coating. There is.

Further, the material of the vibrating body 2 is preferably a rigid one, and in particular, since the tip portion breaks the ceramic coating, a hard and less abrasive material such as ruby is suitable.

Further, 8 is an excavator that excites vibration in the vibrating body 2, and its stroke is controlled by the controller 4. Oscillator 3
For example, a vibrator that uses magnetic field changes such as a solenoid fill or a refill with an iron core, or an ultrasonic oscillator that uses magnetostrictive or piezoelectric effects that can be easily controlled is used. The controller 4 controls the vibration stroke of the oscillator 3 by current control, voltage control, or the like.

Furthermore, in order to obtain a linear coating defect area, the vibrating body 8 is moved parallel to the surface of the steel plate 1 using a drive system consisting of a combination of a rack 5 and a pinion 6 as shown in FIG. It can be achieved.

The film on the surface of the steel plate 1 is destroyed and removed in a linear manner using the film removal equipment purchased as described above. That is, momentum 5X1
0-6, the vibrating body 2 is reciprocated at a speed of 9 m/s or more to apply a force to the surface of the 4 plates 1, and the coating is locally removed so as not to form a dent in the base metal of the flange plate 1. .

Note that after the above treatment, it is also possible to further perform a flattening treatment, and if necessary, a top coating film may be formed.

(Function) First, let's examine the relationship between the momentum of the vibrating body, that is, the impact force applied to the tuning plate, and iron loss based on Fig. 3. Figure 8 shows that when forming film removal areas of 0.31M1i@ at 4-spacing in the width direction of the coil on a 0.23g thick plate that has been finish annealed, the vibration frequency of the vibrating body is changed. This study investigated the relationship with losses. The mass of the vibrating body was 2.59, and the vibration stroke was 0.01 cm.

As can be seen from FIG. 3, iron loss can be advantageously reduced in a high frequency region, that is, a high momentum region. Also, the frequency is 10 H2 or more, that is, the momentum is 5 x 10'''
For samples treated at JC9 m/s or higher, the film in the treated area was completely removed and the effect of lower iron loss was noted.
For each sample treated with a momentum of less than 5×10=kg·m/s, for example at a frequency of 0.111 + 5 H2, film removal was insufficient.

In addition, in this invention, an impact force is applied to the plate surface by a vibrating body, and only the coating on the surface is destroyed and removed in a linear manner, and elastic strain and plastic strain are applied to the surface of the individual plate, thereby reducing iron loss. As for elastic strain, it is easy to detect its presence by removing the film in a linear manner. Therefore, the existence of plastic strain will be discussed next.

The coating applies tension to the steel plate, so when the coating is removed, the tension on the removed side becomes weaker than the tension on the opposite side, and due to the difference in tension between the two, the "r3 plate" Although it is expected that warping will occur, warping does not actually occur.
Since the tension imparted by plastic strain on the surface of the base metal in the film removed portion is equivalent to the lost tension, there is no difference in tension between the front and back sides of the blue plate, and no warpage occurs in the ZD plate.

Furthermore, as shown in Fig. 4, the steel plate from which the coating was removed was
When annealing is performed at a temperature of 0'C or higher, a slight deterioration of iron loss is observed. This is the result of the plastic strain at the outermost surface of the base metal in the part where the film is removed being released by the heat treatment. In other words, the very slight plastic strain on the surface of the base metal in the part where the film is removed generates local tension, subdivides the magnetic domain width, and reduces iron loss.

Fig. 4 shows the iron loss measured after firing a 0.23-meter plate obtained by the manufacturing method of the present invention in an LR atmosphere at 4100 to 900°C for 2 minutes. It is.

Furthermore, after the treatment of this invention, it is possible to apply a coating to increase the insulation properties of the laminate surface.
As shown in FIG. 4, baking at a temperature of less than 700'C is preferable because baking at a temperature of 700°C or higher causes some degree of core loss deterioration.

(Example) Examples of the present invention will be described below.

Example 1 A coating defect area perpendicular to the rolling direction was formed on a plate A having a thickness of 0.20 yua after final annealing using a Tsukibrograver (Vibr04raVer: manufactured by Beulah Co., Ltd.) at a width of Q, 2 mm, and an interval of 4 mm. Example 1 was prepared. Note that the vibrating body has a tip diameter Q, 2 mrn, i i 1,
Using a stainless steel rod with a vibration frequency of 50 H2N and a vibration stroke of 1.0, the momentum is 150 x 10 kg-
m/S.

At the same time, the above-mentioned finish annealed steel plate is coated with thicknesses Q and Q.
mm-, a stainless steel disk with a diameter of 1011 m is 200
Apply a load of 2 and rotate while pressing against the steel plate surface.
Lines were drawn perpendicularly to the rolling direction with a width of 0.2 mm and an interval of 4 *m to obtain ratio row 1.

As a result, in Example 1, there was a defective area of the coating, and no dent was observed on the base metal surface in this area, but in Comparative Example 1, a dent with a depth of 5 μm was observed in the delineated area. , target T4 is 01. It was not destroyed or deleted.

In addition, the magnetic properties and space factors of Example 1 and Comparative Example 1 are shown in Table 1.
It is as follows.

Table 1 Furthermore, Example 1 and Comparative Example 1 were coated with a coating material and baked at 600'C for 2 minutes. Even after the treatment, there was no change in magnetic properties. In addition, 10 pieces of Example 1 were laminated and assembled into a magnetic core, and the iron loss characteristics were measured, but no deterioration was observed.

Example 2 Plate thickness 0.231 coated with coating film after final annealing
For each plate of the ff groove, 100 devices consisting of magnetostrictive vibrators using the drive system shown in Fig. 2 were used.
, 3 ms, an interval of 3 ms to the rolling direction, and a linear coating defect region at an angle of 80° to the rolling direction was formed at once over a o ox in the coil rolling direction.
Therefore, Example 2 was prepared. The weight of the entire vibrator is 100
g, the vibration frequency was 2XIQHz, the stroke was 8 ttm, and the movement was [82000XI Okq-m/S].

In this case, no dents were observed on the base metal surface in the coating defect area.

In addition, on the same steel plate, slits with a width of 5 slots and a width of 0.7 gates were arranged perpendicular to the rolling direction, and a steel shot of 0.35 mB was projected at a speed of 20 to 50 m/Sea to obtain Comparative Example 2. .

Furthermore, the same steel plate has an energy density of 2. OJ/+ff
l.

Comparative Example 3 was obtained by irradiating a pulsed laser in a direction perpendicular to the rolling direction with an irradiation interval of 4 gates and an irradiation width of QJr1 m.

In Comparative Example 2, part of the coating was peeled off at the projection part, and a 4 to 10 micron door dent was observed on the base metal surface.

In Comparative Example 3, the coating in the irradiated area was damaged, and no dents were observed on the surface of the steel base.

Next, the magnetic properties of Example 2, Comparative Example 2, and Comparative Example 3,
Table 2 shows the space factor.

Table 2 Furthermore, even though Example 2 and Comparative Examples 2 and 3 were subjected to baking treatment at 500° C. for 8 minutes, there was no deterioration in the magnetic properties. In addition, in particular Example 2, 20
The iron loss characteristics were measured by laminating the sheets and assembling them into a magnetic core.
There was no deterioration.

Further, the embodiment of the apparatus of the present invention is as described above with reference to FIGS. 1 and 2.

Although the configuration shown in FIG. 2 is used to form the film defective area in a linear shape, it is also possible to use other means such as making the tip of the vibrating body linear or arranging a large number of vibrating bodies in series. .

Furthermore, a machine groove that can automatically control the distance between the J plate and the vibrating body may be adopted, and it is also possible to perform negative feedback control by detecting the degree of destruction of the coating, the presence or absence of dents on the surface of the steel plate base metal, etc. .

(Effects) As explained above, according to the present invention, it is possible to realize a steel plate in which the magnetic flux density does not decrease and the iron loss is reduced, and there is no deterioration in the space factor or the iron loss during the layering. It can be manufactured easily and efficiently.

[Brief explanation of the drawing]

Figs. 1 and 2 are explanatory diagrams showing the film removal device, Fig. 3 is a graph showing the relationship between iron loss and the frequency and momentum of the moving object, and Fig. 4 is a graph showing the relationship between iron loss and the processing according to the present invention. It is a graph showing the relationship with annealing temperature. 1...1 plate 2...vibrating body 3...
Emitter 4...Controller.

Claims (1)

[Scope of Claims] 1. A hot-rolled plate obtained by hot rolling a silicon-containing steel slab is cold-rolled once or twice with intermediate annealing to achieve the final thickness. In manufacturing a grain-oriented silicon steel sheet through a series of steps including decarburization and primary recrystallization annealing, then applying an annealing separator containing MgO as a main component to the surface of the steel sheet, and then performing finish annealing. Stroke-controlled impact force directed toward the steel plate surface at the tip of the vibrating body by a vibrating body that forces the forsterite coating on the surface of the annealed steel plate to reciprocate with a momentum of 5 × 10^-^6 kg・m/S or more. is applied successively to advance the destruction of the forsterite coating without forming a dent on the surface of the base steel sheet, and the defective area of the forsterite coating is formed in a linear shape across the rolling direction of the steel sheet surface. A method for producing grain-oriented silicon steel sheets with ultra-low iron loss. 2. A controller for arranging a vibrating body that is reciprocated by an oscillator in close proximity to a finish-annealed grain-oriented silicon steel plate, and controlling the vibration stroke of the vibrating body toward the surface of the steel plate at the tip of the vibrating body. An apparatus for producing an ultra-low iron loss grain-oriented silicon steel sheet, which is characterized by providing a stroke-controlled impact force to the surface of the steel sheet.