JPS5836052B2 - Processing method for electrical steel sheets - Google Patents

Description

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

Examples of electromagnetic steel sheets include non-oriented electromagnetic steel sheets used in rotating machines such as motors, and grain-oriented electromagnetic steel sheets used in transformers and the like.

Non-oriented electrical steel sheet is a pure iron-based silicon steel sheet containing silicon with a width of 3.5 or less.
It is manufactured by repeating cold rolling and annealing one or two times to make the axis of easy magnetization random with respect to the rolling direction, and then applying an insulation coating treatment.

On the other hand, grain-oriented electrical steel sheets are generally manufactured as follows.

That is, it contains silicon with a ratio of 2.5 to 4.0, and contains AlN, MnSt BN, Se, CuS, Sb as an inhibitor.
After pickling a hot coil containing a predetermined amount of one or more of the elements that give rise to the following conditions, cold rolling and annealing once or twice, secondary recrystallization (1 10) (0
In order to selectively elongate the crystals having the orientation 01), final annealing is performed at 1000-1200°C.

In the case of a batch type in which final annealing is performed on coils, refractory oxides such as magnesia, silica, alumina, titanium oxide, calcium oxide, etc. are used as annealing separators to prevent seizure.

In this case, if an annealing separator containing magnesia as a main component is used, seizure will be prevented, and at the same time, silica on the surface of the steel plate will react with magnesia, resulting in forsterite (2Mgo-S
A glass film containing iO2) as the main ingredient is formed.

This glass coating is not only effective as an insulating coating, but also has a smaller coefficient of thermal expansion than steel plates, and is effective in reducing iron loss and magnetostriction by applying tension to the steel plate during cooling. The mainstream is the production of grain-oriented electrical steel sheets.

The electromagnetic steel sheet that has been subjected to secondary recrystallization through finish annealing to form a glass film is then subjected to an insulating film treatment after removing excess magnesia, for example
As shown in Japanese Patent Publication No. 268, magnesium phosphate processing solution and as shown in Japanese Patent Publication No. 5328375, colloidal silica? -Aluminum phosphate-chromic acid treatment liquid is applied, and at the same time as baking the film, flattening is carried out to remove curls and make the steel plate flat.

In this case, if the film is baked at a high temperature of 7008C or higher, the film turns into glass, and by applying tension to the steel plate during cooling, it is effective in improving iron loss. A film that has the effect of reducing the tension is called a tension film).

In addition to improving iron loss due to the above-mentioned tension effect, this tension coating also has effects on insulation, withstand voltage, and corrosion resistance.

The main object of the present invention is to provide a method for improving the iron lateral surface which is more excellent than the improvement in iron loss due to tension caused by the glass film and the baked film at 700° C. or higher as described above.

In order to achieve this main purpose, the present invention basically uses a laser beam to form the above-mentioned tension coating on one side of an electromagnetic steel sheet, and then irradiates the opposite side with a laser beam to form the above-mentioned tension coating on the surface of the steel sheet. To form a laser mark locally,
The present invention provides a combination technology in which the insulation film treatment on the laser beam irradiated surface is carried out in a temperature range in which the laser beam irradiation effect imparted to the steel plate does not disappear.

The best result can be obtained by performing the laser beam irradiation treatment to the extent that laser marks are generated on the surface of the steel sheet.

It is desirable that these laser marks do not exist from the viewpoint of insulation and voltage resistance, but according to the studies of the present inventors, laser beam irradiation treatment is performed directly on the steel plate, and then an insulating film of a predetermined thickness is formed. By applying this, iron loss can be improved without reducing insulation properties and voltage resistance.

In this case, avoid baking of the insulation film after laser beam irradiation.
If the process is carried out at higher temperatures, the iron loss improving effect of laser beam irradiation gradually disappears.

For this reason, the insulation film treatment performed after the laser beam irradiation treatment is performed in a temperature range where the iron loss improving effect of the laser beam irradiation does not disappear.

The specific plate temperature during film baking varies slightly depending on the laser beam irradiation conditions, etc., but it is preferably 600° C. or lower.

Therefore, the present applicant has already proposed in Japanese Patent Application No. 55-7000 that after irradiating an electrical steel sheet without a glass coating or an electrical steel sheet with a glass coating with a laser beam, it can be insulated at a temperature at which the iron loss improvement effect of the laser beam irradiation does not disappear. We proposed a method of baking the film to improve the reduction in insulation and voltage resistance caused by laser beam irradiation marks.

However, as a result of a more detailed study, the inventors of the present invention found that if a tension film treatment can be performed even after laser beam irradiation treatment, an even greater effect of improving iron loss can be obtained. As a result of careful consideration of the possibility of application, we focused on the fact that the baking temperature can be set arbitrarily before the laser beam irradiation treatment. It was a success.

In fact, if a tension coating is actually formed on the surface of an electrical steel sheet and a laser beam irradiation treatment is performed on the surface, the iron loss will be dramatically improved due to the synergistic effect of the laser beam irradiation treatment on the tension coating. (This has already been filed in Japanese Patent Application No. 56-35962).

However, in this method, a two-layer coating is obtained by treating the tension coating and the insulation coating twice, resulting in a thick coating, resulting in a drawback that the space wheel and adhesion are slightly inferior.

Therefore, in the present invention, we have further investigated and established a method for solving the above-mentioned drawbacks.

First, regarding the tension coating, we have found that it is not necessarily necessary to apply the tension coating to both sides of the steel plate in order to improve iron loss through the tension effect, and that almost the same effect of improving iron loss can be obtained by applying the tension coating to only one side.

The amount of coating in this case varies depending on the composition of the tension coating, but generally 3 to 7 g/m'' is preferable.

Next, regarding the effect of laser beam irradiation on improving the iron side, it was found that single-sided irradiation was as good as double-sided irradiation.

The present invention has been made based on the above findings.

In the present invention, first, the tension coating is formed only on one side of the steel plate.

Next, laser beam irradiation treatment is performed on one side on which the tension coating is not formed.

Finally, an insulating film treatment is performed on the laser beam irradiation treated surface.

According to the present invention, although the tension coating and the insulation coating are treated twice, the coating becomes a single-layer coating on one side and there is no increase in the coating thickness, so it is effectively prevented from deteriorating the adhesion of the unloading vehicle. This can be prevented.

That is, according to the present invention, it is possible to obtain an iron loss improvement effect due to the synergistic effect of the tension coating and laser beam irradiation, and to obtain an electromagnetic steel sheet that has excellent insulation properties, voltage resistance, corrosion resistance, adhesion properties, and loading wheel performance. It is.

The insulating film applied to the laser beam irradiation surface has insulating properties,
In order to ensure voltage resistance and corrosion resistance, a coating amount of 1 to 4 g/m'' is preferable.

The influence of the tension film on the surface of the electrical steel sheet on laser irradiation will be explained below with reference to FIG. 1.

In the figure, Δ marks are for glass film only, ○ marks are with tension film on both sides, mouth marks are with tension film on one side, ▲ marks are glass film + laser beam irradiation, ● marks are double-sided tension film + laser beam irradiation, ■ marks are on one side Laser beam irradiation on the opposite side of the tension coating (
method of the present invention).

The laser beam irradiation conditions are (i) energy density 1
7J/history, (ii) point trace diameter 0.2 fence, (iii)
The trace distance is 0.3 mm, and (iv) the distance in the L direction is 5 mm.

The insulation film baking after laser beam irradiation was carried out at 500°C (plate temperature).

As is clear from Figure 1, a tension film is formed on both sides and one side at the same time as flattening on the glass film (○, mouth).
, the iron loss is improved compared to the glass coating only (△), and when laser beam irradiation is performed on this double-sided and single-sided tension coating (●, ■), and when the laser beam is irradiated on the glass coating (▲ ), the iron loss is improved by 0.05 to 0.07, and a very excellent iron loss can be obtained.

In this way, even if a tension coating is applied on both sides and a laser beam is irradiated on both sides, or even if a tension coating is applied only on one side and the laser beam is irradiated only on the opposite side, iron loss will not be improved. Therefore, comparable values can be obtained.

Next, in Figure 2, the iron loss of the electrical steel sheet with a tension coating on one side was 1.05 wAg at wl7/50, but it was reduced to 0.9 by applying laser beam irradiation treatment to the opposite side.
It decreased at 21.

However, the iron loss after the insulation coating treatment increases depending on the temperature (plate temperature) during the subsequent insulation coating treatment, and in this example, the effect deteriorates extremely when the plate temperature exceeds 600'C. It turned out that.

Among these, the best option is to perform the baking process at a plate temperature of 600°C or less, which allows the iron loss of the final product after insulation coating treatment to be equal to or lower than that after laser beam irradiation treatment. becomes.

The laser beam irradiation used in carrying out the present invention is not limited in any way; for example, continuous linear irradiation,
Either point irradiation, broken line irradiation, etc. may be used.

Furthermore, in order to improve the magnetic properties in the rolling direction L, the irradiation direction on the electrical steel sheet is irradiated at an angle of 200 degrees or less from the perpendicular direction C, which increases the iron loss improvement.

On the other hand, in order to improve iron loss in a direction perpendicular to the rolling direction, the rolling direction is preferred.

Now, to show one application example when using a pulsed laser beam, in order to improve iron loss in the rolling direction, the laser beam diameter d is 0.01 when the energy density P is 0.01 to 1000 J/i. ~1 mark is made so that the center distance of the mark is 0.01 to 2 mm in the direction perpendicular to the rolling direction,
Furthermore, irradiation is applied so as to form a trace array of 1 to 30 mm in the rolling direction.

In order to form a trace array of 1 to 30 mm in the rolling direction, the irradiation may be performed approximately perpendicular to the rolling direction, or in a sawtooth shape or a sine curve shape, depending on the optical system used.

The time width of the laser pulse is 1 ns to 100 ms.

On the other hand, when irradiating with a continuous laser beam, the laser beam diameter is 0.01 to 1 m.
The trace of m has an energy density P of 0.01 to 1000 J/
What is necessary is to scan the laser beam so that it becomes a.

The difference between pulsed irradiation and continuous irradiation is that the former forms a series of trace points, whereas the latter forms continuous traces; other specifications are the same.

One implementation process for the method of the present invention is to coat an electrical steel sheet with an annealing separator containing magnesia as a main ingredient.
Finished and high temperature annealed at 1200℃, forsterite (2M
A glass film containing go-SiO2 as a main component is formed.

This coil is flattened at a temperature of 700 to 900°C to remove curls, and at the same time a tension film is applied and baked on one side to apply tension to the steel plate.The opposite side is then subjected to laser beam irradiation treatment. When the plate temperature is below 600℃,
This is a method in which an insulating film is applied to the surface irradiated with a laser beam.

The tension film treatment carried out simultaneously with flattening in the present invention can withstand baking at temperatures above 700°C and imparts tension to the steel plate upon cooling. For example, the colloidal silica, aluminum phosphate, and chromic acid treatment described in the above-mentioned Japanese Patent Publication No. 5328375 liquid, colloidal silica, phosphate, and chromate treatment liquid described in JP-A-52-25296, magnesium ion as described in US Pat. No. 580,449, ? Although a treatment liquid such as a treatment liquid containing phosphoric acid, silica, and chromium ions is used, the treatment liquid is not limited to the above-mentioned treatment liquid as long as it can apply tension to the steel plate.

Next, after laser beam irradiation treatment, the plate temperature is 6
The main component of the treatment solution for insulation coating treatment at temperatures below 00°C is a treatment solution containing one or more of phosphoric acid and chromate, and colloidal silica, colloidal alumina, titanium oxide, and boric acid compounds. Some products contain one or more of these.

In addition, as reducing agents for chromic acid, organic compounds such as polyhydric alcohols and glycerin, water-soluble,
Or emulsion resin, high resistance, 1μ for improved workability
1 of an organic compound such as an organic resin powder having a particle size of
A species or two or more species can be included.

In addition to this, it is also possible to form an insulating film by irradiating ultraviolet rays or the like.

Although the above description has mainly been given to the case of grain-oriented electrical steel sheets, the present invention can also be applied to other non-oriented electrical steel sheets.

Next, an example will be explained.

Example I Si2.9%, C0.003%, Mn 0.0 7 5
%, AlO. Unidirectional electrical steel sheet containing 028% (0
．． A plate having a thickness of 30 mm) was manufactured by the following process.

After the hot coil is cold-rolled and annealed once, magnesia is applied and dried, wound into a coil, and final high-temperature annealing is performed at 1150°C for secondary recrystallization, after which excess magnesia is removed and a glass film is formed. A magnetic steel sheet having the following properties was obtained.

Divide this coil into 3 parts, 1 coil is 850℃ x 70se
At the same time as flattening, treatment liquid A was applied to one side and baked.

The amount of coating is 4. 9/m" (inventive material).

At the same time as the flattening, the second coil was coated with treatment liquid A on both sides and baked.

The amount of coating is 4. 0 F/rn” (
Comparative material a).

The third coil was subjected to only flattening at 8500C x 70 sec (comparative material b).

Unidirectional electrical steel sheet obtained in this way? Samples were taken from the specimens, and the materials of the present invention were subjected to the following treatments B and C, and the comparative materials were subjected to treatments D and E, and various characteristics were tested.

Inventive material A treatment: A tension film is baked on one side at the same time as flattening.

(1) Tension film treatment liquid (4) Colloidal silica 20 cc 1 2 0 cc 50 t magnesium phosphate 3 0 cc 50 polyaluminum phosphate 3 0 cc chromic anhydride
6I! 9B treatment: After the A treatment, a pulsed laser beam irradiation treatment is performed on the opposite side.

(1) Laser irradiation conditions α) Energy density: 1 7 J /iω Point-like trace diameter: 0.2 mm (I [[) Point-like mark C direction center distance: 0.3 mm (I
V) Trace distance in the direction: 5mm Insulating film treatment after C treatment 2B treatment (1) Insulating film treatment (I) Treatment liquid 20 Colloidal silica 1 2 0 cc 50 Aluminum polyphosphate 7 0 cc Chromic anhydride
5g Boric acid 29 [I] Baking temperature (plate temperature) 500,600,700,
800℃ @) Coating amount Laser irradiation surface 4 g/m” Comparative material a D treatment: Laser beam irradiation treatment on a material with a tension film on both sides (comparative material a) and 11 materials with hip flattening (comparative material b) Laser irradiation conditions are the same as for B treatment.

E treatment = insulation film treatment after D treatment Insulating film treatment solution and baking temperature are the same as C treatment. The coating amount is 4 g/m” (both sides). The results of the experiment as described above are shown in Table 1.

As is clear from Table 1, the material in which a tension film is baked on one or both sides at the same time as flattening has better iron loss than in the case of only flattening (comparative material b). By irradiating the laser beam onto the tension coating, which is the surface of both materials that does not have a tension coating, a large improvement in core loss can be obtained.Furthermore, by baking the insulating coating at a temperature below 600℃, it is possible to create a 1-inch, excellent material that maintains the laser beam irradiation effect. Provides excellent insulation and withstand voltage.

However, compared to comparative material a, which had a tension coating on both sides and an insulating coating on both sides, the material of the present invention was found to have better adhesion of the coating and better occupancy due to the thinner coating.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the influence of tension coating and laser beam irradiation on improving iron loss, and FIG. 2 is a diagram showing the relationship between insulation coating baking temperature and iron loss. Figure 1: △Glass coating only, ○Double-sided tension coating, (4.
5 g/m”) single-sided tension coating (4.5 9/
m”), ▲Glass film + laser irradiation, ●Double-sided tension film 10 laser irradiation, 1 side tension film 10 sides laser irradiation.

Claims (1)

[Claims] 1 A tension coating is formed on one side of a magnetic steel sheet, the opposite side is treated with laser beam irradiation to create laser irradiation marks, and then when the insulation coating is applied to the laser beam irradiated surface, the laser beam irradiation effect disappears. A method for processing electrical steel sheets, which is characterized by carrying out the treatment in a temperature range where the temperature is low.