JPS5826409B2 - Manufacturing method of electrical steel sheet with excellent iron loss characteristics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an electrical steel sheet with excellent magnetic properties, insulation properties, and space factor.

The inventors of the present invention have previously invented a method to refine the magnetic domains in the irradiated area by irradiating the surface of an electrical steel sheet after finish annealing with a laser beam, thereby significantly reducing the iron loss of the electrical steel sheet and improving its characteristics, and patented the invention. No. 53-91217, Japanese Unexamined Patent Publication No. 53-55
A patent application was filed as No.-1 8 5 6 6.

The timing of laser beam irradiation in this invention may be after final annealing (so-called secondary crystal annealing), before the application of the insulation film, or after the first application; When a final product is irradiated with a laser beam, the surface of the steel plate in the irradiated area may be locally evaporated (approximately 10-5 m), including the insulation film, due to the irradiation of the laser beam. There was a risk of deterioration of insulation properties and, if the surface of the steel plate was exposed, rusting would occur from that part.

The present invention aims to solve these problems.

That is, the present invention irradiates the surface of an electrical steel sheet with an insulating film on the surface with a laser beam in a direction substantially perpendicular to the rolling direction and/or in a direction parallel to the rolling direction, and then forms an insulating film on the portion irradiated with the laser beam. This invention relates to a method for manufacturing repainted products.

The details of the present invention will be explained below using examples.

FIG. 1 schematically shows a state in which a laser beam is irradiated onto an electromagnetic steel sheet having an insulating film applied to its surface. 1 is the electromagnetic steel plate, 2 is the insulating film, and 3 is the laser beam irradiation mark.

As is clear from this figure, the surface of the electromagnetic steel sheet is instantaneously evaporated by laser beam irradiation, and the reaction force at that time causes local dislocations to form within the steel sheet, resulting in fragmentation of the magnetic domain and reduction in iron loss. However, it is necessary to re-apply the insulating film in areas where the insulating film becomes thinner due to laser beam irradiation or where the steel plate surface is exposed due to evaporation and scattering.

As for the repainting method, it is possible to repaint the entire surface with the insulating film or manually apply the insulating film agent to the laser beam irradiated area, but from the point of view of efficiency it is preferable to perform electrodeposition coating locally. Since this method is advantageous, the electrodeposition coating method will be explained below.

After irradiating an electromagnetic steel sheet with an insulating film on its surface with a laser beam, the insulating film 2 at the edges is removed or trimmed and slit to expose the base electromagnetic steel sheet 1 at the edges, and then exposed to an electrodeposition bath. Electrodeposition coating is applied to the exposed parts of the steel plate by laser beam irradiation, including the ends, by immersing it in the electrodeposition bath, pressing the button on the electrodeposition bath side, applying electricity from the above-mentioned end, and electrolyzing between the counter electrode and the appropriately provided counter electrode. It can be performed.

In addition, the laser beam is scanned in a fixed direction, and a roller-shaped energizing roll 4 as shown in FIG. An electromagnetic steel sheet that has been irradiated with a laser beam is immersed in an electrodeposition bath, and electrolysis is performed between it and an appropriately provided counter electrode. When the current-carrying roll comes into contact with the laser beam irradiation area, electricity is applied and the steel sheet in the electrodeposition bath is exposed. Electrodeposition coating can be applied to the parts.

Electrodeposition conditions may be 100 to 300cm, which is used for automobiles, but a lower voltage of 40 to 10cm may be used in consideration of safety to the human body.
Approximately 0V is preferable.

Although the electrodeposition time varies depending on the coating material, it is the time necessary for the electrodeposition coating layer to grow to the thickness of the original insulating film, and usually several seconds to several tens of seconds is sufficient.

Further, the electrodeposition paint that can be used in the present invention may be anionic or cationic, and the electrodeposition method usually uses a direct current method, but if the paint is anionic as described below, an alternating current method may be used.

For anionic resins, acrylic, polyester, epoxy, butadiene, and oleoresinous resins that have carboxyl groups in their molecules are neutralized with amines, ammonia, or alkalis to make them water-soluble.

For example, (1) butyl acrylate and acrylic acid copolymer (
(62 mol/38 mol), (2) isobutyl acrylate, acrylic acid, and melamine copolymer (82 mol/16 mol/
2 mol L(3) maleated oil, etc.

In the case of residual cationic resins, epoxy, acrylic, or urethane resins having amino groups in their molecules are neutralized with acetic acid, phosphoric acid, etc. to make them water-soluble.

For example, (1) Nirekron 900 manufactured by Kansai Paint Co., Ltd.
0, (2) Power Top U-3 manufactured by Nippon Paint Co., Ltd.
It is 0 etc.

After electrodeposition, it is desirable to omit baking or to lower the baking temperature.

For this purpose, (1) use a paint with a high degree of polymerization or (2) replace a part of the carboxyl group with Zn, Fe, Ni,
It is desirable to use SntAltCr salt.

Examples of the present invention will be shown below.

Example 1 A copolymer of 62 moles of butyl acrylate and 38 moles of acrylic acid (molecular weight 5oooo) was neutralized with ammonia.
60V x 2 seconds (anode) using 0% solution (pH 6,5)
Electrodeposition coating was applied to the laser-marked areas of the electromagnetic steel sheet coated under the following conditions.

Example 2 68 mol of isobutyl acrylate, 1 mol of methyl methacrylate
Copolymer of 6 moles and 16 moles of acrylic acid (molecular weight 400
acrylic acid 5 to a solution of 0) neutralized with ammonia.
Add moles of zinc hydroxide, react, and adjust the pH
A solution of 7.0 was prepared.

Using this solution, electrodepositing was performed on the laser-marked areas of the electrical steel sheet on which the insulating film had been applied under the conditions of 70 V and 2 seconds (anode).

Example 3 A commercially available epoxy-based cationic electrodeposition paint (Kansai Paint Nireclone 9100) clear was adjusted to pH 6.3, and cathodic electrodeposition was applied to the laser traced areas of an electrical steel sheet coated with an insulating film at 100V for 5 seconds.

In all of the above examples, the laser beam irradiated area could be completely covered, and the insulation and corrosion resistance could be maintained at the same level as before the laser beam irradiation.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing a state in which a laser beam is irradiated onto an electromagnetic steel sheet having an insulating film applied to its surface, and FIG. 2 is a diagram showing a mode of electrodeposition coating. 1: Electromagnetic steel sheet, 2: Insulating film, 3: Laser beam irradiation marks, 4: Current-carrying roll.

Claims (1)

[Claims] 1. A patent characterized in that a laser beam is irradiated substantially perpendicularly and/or parallel to the rolling direction to an electromagnetic steel sheet having an insulating film applied to the surface, and the irradiated area is further coated with an insulating agent. manufacturing method.