JPS5826406B2 - Method and device for improving iron loss value of electrical steel sheet - Google Patents

Description

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

Many means and methods have been proposed to improve the iron loss value of electrical steel sheets. This is not a preferable method for an iron core constructed as such, and it has been difficult to put it into practical use.

The present inventors focused on the fact that the iron loss value of electrical steel sheets was improved by irradiating the electrical steel sheets with laser light, and previously published Japanese Patent Application No. 53-9 [2] 7, JP-A No. 55-18566. proposed a method of irradiating the surface of a grain-oriented electrical steel sheet with a finish-yaki finish using laser light.

The present invention further improves the above proposal, and the first invention is to condense pulsed laser light oscillated from a laser oscillation device to a desired energy density value using a condenser lens, so that the condensed point is always focused on the irradiated electromagnetic field. The gist is to irradiate the beam so that it is on the surface of the steel plate, and the condensed points are arranged in a row in a direction substantially perpendicular to the rolling direction of the steel plate.

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, crystallographically (11
The (110) plane of each crystal grain of the plate thickness, which is displayed as the 0) (001) structure, is parallel to the plate surface, and the easy axis of magnetization (001
) is parallel to the rolling direction, and its production requires extremely strict process control; however, the present invention is applicable to steel sheets or coils that have undergone final annealing, or those on which an insulating film has been formed. Ru.

According to the findings of the present inventors, the laser beam has an irradiation focal point diameter (d): o, between o1 and 1 irradiation focal points, and an interval in the C direction between the centers of the irradiation focal points (a): O, between O1 and 1 irradiation focal points Row direction spacing (1): 1. o~3oTt71L Irradiation energy density (p): 0.01~1000J/i depending on the specifications, the pulse oscillation time width is Ins or more]00m
It is preferably 5 or less.

When the pulse oscillation time width exceeds 100 m5, the thermal melting phenomenon becomes dominant rather than the effect of improving the iron loss characteristics that occurs in the steel plate during irradiation, causing changes in the crystal structure, etc., which substantially reduces the improvement of the iron loss value. No effect can be expected.

According to the present invention, laser light is adjusted from a laser oscillation device to be focused on the surface of an electromagnetic steel sheet via a focusing unit.

Therefore, the total reflection mirror and the condensing lens are integrated into the condensing unit.

When a convex lens is used as a condensing lens, it condenses the light in the form of dots on a diameter of 1.0 or less, so that the condensing points are arranged in a row in the direction perpendicular to the rolling direction of the electrical steel sheet (hereinafter referred to as the C direction). It is preferable to irradiate the area.

Also, a semi-cylindrical condensing lens is used to condense the light into a thin line having a width in the L direction of LOmrn or less and a length in the C direction of LOmrn or more.
It is also suitable for practical skill to irradiate the steel plate in a linear manner in the C direction.

The invention will now be explained with reference to the drawings.

In FIG. 1, a laser oscillation device 2 oscillates a pulsed laser beam 7 having the energy necessary for the present invention, and total reflection □
The light is irradiated through a condensing unit 3 consisting of a mirror 4 and a convex condensing lens 5 so as to be condensed onto the surface of the irradiated electromagnetic steel sheet 1ε cypress.

For the experiment, pulsed laser light focused below LOmmφ was irradiated, and the condensing unit 3 was moved in the C direction of the steel plate 1 to form converging points on the surface of the steel plate 1 in a row. do.

It is preferable that the irradiation interval in the L direction of the array of condensed points by this pulsed laser beam is 1.0 to 30 mm.

FIG. 2 shows another embodiment of the invention.

The condensing unit 3 integrally includes a total reflection mirror 4 and a semi-cylindrical condensing lens 6.

FIG. 3 is an explanatory diagram of condensing light into a line by the semi-cylindrical condensing lens 6.

In the figure, the thin line-shaped condensing portion 8 with l>■, 0rnr/LW<17ft7IL is shown as a scale.

Therefore, the condensing part irradiated with 1)>LOmrn is
They can be formed in rows in the C direction.

Next, examples of the present invention will be shown.

Example 1 Using a YAG laser with a peak output of 5 KW, a repetition frequency of 3 KHz, and a pulse width of 150 n-see, the irradiation configuration shown in Fig. 1 using a convex condenser lens with a focal length of 60 mm was used to finish a width of 900 mm Irradiation was carried out in the C direction of the surface of the fired electromagnetic steel sheet while moving the light focusing unit at a speed of 900 mu/sec with a focusing point diameter of 0.3 mm.

Irradiation interval l in the direction of condensing point array is 2.5 mm, 5 Omr
n, ] 0. Omm, 20. Corresponding to Omrn, the iron loss value decreased as shown below.

Example 2 Using a YAG laser with a peak output of 5 KW, a repetition frequency of 1 KHz, and a pulse width of 50 n-5ee,
With the irradiation configuration shown in Fig. 2 using a cylindrical condensing lens with a focal length of 30 mm, the condensing section is placed in the C direction on the surface of a 900 mm wide finished fired electromagnetic steel plate with a length of about 1.5 mrn and a width of about 0.0 mm. Focus the light condensing unit into a thin line of 0.05 mm.
Irradiation was performed while moving at a speed of 0.00 mm/sec.

The irradiation interval l in the direction of the condensed beam array is 2.5mπ5, Omm,
10.0mm, 20. Corresponding to Omrn, the iron loss value decreased as shown below.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the present invention, FIG. 2 is an explanatory diagram of another embodiment of the present invention, and FIG. 3 is an explanatory diagram of the main part of FIG. 2. 1...Electromagnetic steel plate, 2...Laser oscillation device, 3...
・Condensing unit, 4... Total reflection □R 5... Condensing lens.

Claims (1)

[Scope of Claims] 1. A pulsed laser beam oscillated from a laser oscillation device is condensed to a desired energy density value using a condensing lens so that the condensed point is always on the surface of an electromagnetic steel sheet to be irradiated, and A method for improving the iron loss value of an electrical steel sheet, characterized by irradiating it so that condensed light points are arranged in a row in a direction substantially perpendicular to the rolling direction. 2. A method for improving the iron loss value of an electrical steel sheet according to claim 1, which comprises irradiating a pulsed laser beam focused to less than 2 LO mmφ. 3. A method for improving the iron loss value of an electrical steel sheet according to claim 1, which comprises irradiating a pulsed laser beam condensed into a fine line with a width of 3 loam or less and a length of 1.0 or more. 4. A laser oscillation device that oscillates pulsed laser light;
The condensing unit consisting of a total reflection mirror and a condensing lens is placed parallel to the surface of the electromagnetic steel sheet, and in the rolling direction of the steel sheet! A device for improving the iron loss value of electrical steel sheets, characterized by being able to move in a right angle direction.