JPS5826411B2 - Method and device for improving properties of electrical steel sheets - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for improving the magnetic properties of electrical steel sheets.

Many means and methods have been proposed to improve the magnetic properties of electromagnetic steel sheets, but for example, applying mechanical processing to the surface of the steel sheets as described in Japanese Patent Publication No. 5O No. 35679 has been proposed to improve the magnetic properties of electromagnetic steel sheets. This is not a preferable method for use with iron cores constructed of iron cores, and it has been difficult to put it into practical use.

The present inventors noticed that the magnetic properties of an electrical steel sheet could be improved by irradiating the electrical steel sheet with a laser beam, and previously published Japanese Patent Application No. 53-91217, Japanese Patent Application Laid-open No. 55-18566, and Japanese Patent Application No. 127666/1982. No. JP-A-56-51522
In this issue, we proposed a method of irradiating laser light onto the surface of grain-oriented electrical steel sheets for finishing firing.

The present invention is a further innovative improvement of the above proposal, and the first invention is to guide pulsed laser light oscillated from a laser oscillation device through an optical fiber bundle that can transmit the laser light well, and to cover each fiber. The laser beams from each fiber array are arranged perpendicular to the rolling direction on the surface of the irradiated electromagnetic steel sheet, and the laser beams from each fiber row are focused so that they are always on the surface of the steel sheet. The gist of this method is to irradiate the steel plate with oscillating light at regular intervals in the rolling direction.

Furthermore, a second invention is directed to an apparatus for carrying out the method of the first invention.

As is well known, grain-oriented electrical steel sheets, for example, are crystallographically (110
) [001] of each grain of plate meat displayed as the structure (
11o) The plane is parallel to the plate surface, and the axis of easy magnetization [Oo1]
is parallel to the rolling direction, and its production requires extremely strict process control; however, the present invention is applicable to steel plates or coils that have undergone final finish annealing, or those on which an insulating film has been formed. .

According to the findings of the present inventors, the energy density P is 0.
OI J /crj, it is desirable to perform spot irradiation with Par/L/laser light of 1000 J/cf11 or less.

At this time, it is preferable that the pulse oscillation time width is 100 m5 or less.

If the pulse oscillation time width exceeds 100 m5, the thermal melting phenomenon that occurs in the steel plate during irradiation causes changes in the crystal structure, and no substantial improvement in magnetic properties can be expected.

In the present invention, laser light is adjusted so that it is irradiated from a laser oscillation device onto the surface of an electromagnetic steel sheet via a plurality of optical fibers.

At this time, one end of the bundled multiple optical fibers (optical fiber bundle) is installed in the laser beam path emitted from the laser beam oscillation device, and the other end is used to roll each fiber at a predetermined height above the surface of the electromagnetic steel sheet to be irradiated. Linearly arranged one by one at predetermined intervals in the direction perpendicular to the direction.

A condensing lens is installed on the end face of each fiber arranged to face the surface of the electromagnetic steel plate.

Therefore, the laser light emitted from the oscillator and transmitted through the fiber is focused by the lens and irradiated onto the surface of the electromagnetic steel sheet.

That is, the present invention has an industrially very large advantage in that it is not affected by the unavoidable corrugation properties during the production of electrical steel sheets due to non-contact operation.

The present invention will be described in detail below with reference to the drawings.

In FIG. 1, a laser oscillation device 1 oscillates a pulsed laser beam having the irradiation energy necessary for the present invention, and the laser beam 2 is guided to an incident part 4 of an optical fiber bundle 3 installed in accordance with the laser beam. After passing through each fiber 7, it reaches the optical fiber bundle output part 5, which is linearly arranged one by one in the direction perpendicular to the rolling direction (direction C) above the surface of the steel plate 1o, and is condensed by a condenser lens 6. The beam is then irradiated onto the steel plate surface.

FIG. 2 is an example of a sectional view of the optical fiber bundle 3 according to the present invention, showing a collective bundle of optical fibers 7.

FIG. 3 shows the positional relationship between the optical fiber bundle output part 5 and the steel plate 1o, which is a row in which condenser lenses 6 are provided in contact with the intervening fiber 7.

FIG. 4 is an enlarged view of the optical fiber bundle output section 5 of the present invention.
is a rear view, and b is a side view.

The irradiation diameter of the laser beam focused by one lens of the present invention is 0.004 to 1 rrrm, and the energy density is 0.0
1 to 1000 J/c4.

Also, the interval in the C direction of the laser beams condensed and irradiated by each lens (the interval in the C direction of the condenser lens array) a is 0.1 to 30 WmL.
shall be.

Further, the irradiation interval in the L direction is set to 0.01 to 30 times.

That is, in the present invention, when a grain-oriented electrical steel sheet to be irradiated having a plate portion W (rran) moves at a speed V (tra/S), the laser beam irradiation interval a (m) in the width direction of the steel sheet is
+rL) Laser light irradiation interval 1- (m
m), the required number of fibers to be installed in the width direction of the steel sheet as the repetition frequency f (Hz) of the pulsed laser Next, embodiments of the present invention will be shown.

Example 1 A finish-sintered grain-oriented electrical steel sheet moving at a speed of V = 1000 mm/S is subjected to a = 0.5 r in the C direction.
Optical fibers are arranged at random intervals, and the laser light energy density P from each fiber is 2.5 J/crA, and the pulse oscillation time width is about 100 nsec.
AG laser was irradiated with a repetition frequency of 200 Hz.

The core loss values and magnetic flux densities in the L direction before and after laser beam irradiation were measured for several samples, and are listed in Table 1.

Table 1 shows that even though the iron loss value before irradiation was quite large and varied, the iron loss value was significantly reduced by laser light irradiation, and the variation was also very small.

Moreover, the magnetic flux density after irradiation hardly changed.

Example 2 A = 5 ru in the C direction on a finish annealing grain-oriented electrical steel sheet moving at a speed of V = 1000 rran/S
Optical fibers are arranged at intervals of n, and the laser light energy density P from each fiber is 2.5 J/cd, and the YAG pulse oscillation time width is 100 nsec.
The laser was irradiated with a repetition frequency of 2 KHz.

*The iron loss value and magnetic flux density in the C direction after laser beam irradiation were measured on a few samples, and the results shown in Table 2 were obtained.

Table 2 shows that the iron loss value in the C direction was also significantly reduced by the laser beam irradiation.

Example 3 Laser light irradiation was performed on a grain-oriented electrical steel sheet after insulation coating ☆☆ film treatment, which was moving at a speed of V = 1000 rran/S, under the same conditions as in Example 1, and the L-direction magnetic properties before and after irradiation were measured. Changes were measured.

This is shown in Table 3. Table 3 shows that the iron loss value after irradiation was significantly reduced compared to the iron loss value before irradiation.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of the present invention, Fig. 2 is an explanatory diagram of the input part of the optical fiber, Fig. 3 is an explanatory diagram of the output part, and Fig. 4 is an explanatory diagram of the optical fiber entrance part.
The figure shows a rear view and a side view of the emission section. 1: Laser oscillation device, 2: Laser light, 3: Optical fiber bundle, 4: Incident section, 5: Output section, 6: Condensing lens, 7
: Optical fiber 10 bidirectional electrical steel sheet.

Claims (1)

[Claims] 1. A method for improving the properties of an electrical steel sheet, which comprises irradiating the surface of the steel sheet with a laser beam via an optical fiber bundle. 2. An apparatus for improving characteristics of an electrical steel sheet, characterized in that one end of an optical fiber bundle is placed opposite to a laser beam oscillation device, and the other end is arranged above the surface of the steel sheet in a direction perpendicular to the rolling direction. 3. The apparatus for improving characteristics of an electrical steel sheet according to claim 2, wherein a condenser lens is attached to the end of each optical fiber on the steel sheet side.