JPS61183457A - Manufacture of grain-oriented electrical steel sheet having extremely superior magnetic characteritic - Google Patents

Abstract

PURPOSE:To manufacture a grain-oriented electrical steel sheet having extremely superior magnetic characteristics by plating a grain-oriented electrical steel sheet subjected to finish annealing with a penetrating body to form a penetrated body different from the steel sheet in composition or structure at intervals. CONSTITUTION:A surface film such as a glass film or an insulating film on a grain-oriented electrical steel sheet subjected to finish annealing is removed entirely or partially at intervals. The steel sheet is plated with a penetrating body by >=0.05g/m<2> to form a penetrated body different from the steel sheet in composition or structure at internals. The magnetic domain is subdivided by the formation. An insulating film is then formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing grain-oriented electrical steel sheets with extremely excellent magnetic properties), specifically, the iron loss improvement effect does not disappear even after heat treatment. The present invention relates to a method for manufacturing grain-oriented electrical steel sheets that have extremely low iron loss and good magnetic flux density through magnetic domain refining.

[Conventional technology]

Grain-oriented electrical steel sheets are mainly used as iron core materials for transformers and other electrical equipment, so they need to have good excitation characteristics and iron loss characteristics.

This steel plate utilizes the secondary recrystallization phenomenon and has a rolling surface of (110
) planes with the (001) axis in the rolling direction, secondary recrystallized grains having a so-called Goss orientation are developed. (110
) (001) By increasing the degree of integration in the orientation and reducing deviation from the rolling direction as much as possible, products with excellent excitation characteristics, iron loss characteristics, etc. are being manufactured. .

By the way, as the degree of integration of the (110) < 001) orientation increases, the crystal grains become larger, and since the domain wall penetrates the grain boundary, the magnetic domain becomes larger. There is a phenomenon that cannot happen.

For example, Japanese Patent Publication No. 58-5968 discloses a technique for eliminating the above-mentioned phenomenon and reducing iron loss.

This is done by pressing small balls etc. onto the surface of the final finish fired pure unidirectional electromagnetic steel sheet to form dents with a depth of 5μ or less and applying linear minute strain to subdivide the magnetic domains. It is intended to improve losses.

In addition, Japanese Patent Publication No. 58-26410 discloses that at least one trace of laser irradiation is formed on the surface of each secondary recrystallized crystal grain generated during final finish annealing to subdivide the magnetic domain and reduce iron loss. It is proposed that

These Special Publications No. 58-5968 and Special Publication No. 58-2
According to the method disclosed in No. 6410, iron loss is improved by applying local minute strain to the surface of a grain-oriented electrical steel sheet, and an ultra-low iron loss material can be obtained.

[Problem that the invention seeks to solve]

However, when the ultra-low iron loss material obtained as described above is annealed, the iron loss improving effect is lost. For example, in strain relief annealing when manufacturing a wound core, the iron loss improving effect is lost.

The present invention efficiently performs magnetic domain refining that does not lose its iron loss improvement effect even when subjected to heat treatment, such as strain relief annealing, to achieve extremely low iron loss, good magnetic flux density, and good corrosion resistance and insulation properties. The purpose is to provide a method for stably manufacturing grain-oriented electrical steel sheets. Another object of the present invention is to produce a grain-oriented electrical steel sheet whose core loss does not deteriorate even when subjected to the strain relief annealing.

The present inventors performed strain relief annealing after magnetic domain refining, for example, at 700°C.
It is a grain-oriented electrical steel sheet that does not lose its iron loss improvement effect even after heat treatment at temperatures of ~900°C.It is a grain-oriented electrical steel sheet that has extremely low iron loss due to efficient magnetic domain refining, and also has no rust and excellent interlayer resistance. We conducted experiments and investigated ways to manufacture products stably and with good productivity.

[Means for solving problems]

As a result, a finish-annealed grain-oriented electrical steel sheet is plated with a penetrant, and an alloy layer is formed by a reaction with a penetrant, such as a steel plate or a surface coating, that differs from the steel composition or structure of the steel sheet.
When surface reaction products, diffused substances, etc. are formed at intervals, magnetic domain buds are generated on both sides of the intruder, and when the steel sheet is magnetized, the magnetic domains are subdivided, and then heat treatment such as strain relief annealing is performed. Even after applying this method, the iron loss improvement effect of magnetic domain refinement did not disappear.

It has been found that grain-oriented electrical steel sheets with extremely low iron loss can be stably obtained.

Next, an insulating coating solution containing one or more of phosphoric acid, phosphate, chromic acid, chromate, dichromate, and colloidal silica is applied to the steel plate and baked to form an insulating coating. This prevents the plated penetrable body from peeling off during subsequent work due to coil slipping, etc., and prevents it from evaporating during annealing, stabilizes the formation of the penetrant body, and has good corrosion resistance and insulation properties. I found out.

The present invention provides a method for stably and productively manufacturing a grain-oriented electrical steel sheet with extremely low iron loss, excellent magnetic properties, and excellent corrosion resistance and insulation properties. The feature is that surface coatings such as glass coatings and insulation coatings are removed from finish annealed grain-oriented electrical steel sheets, and the steel plates are plated with penetrable bodies with a basis weight of 0.0517 m or more to change the steel composition or steel structure. The patented manufacturing method is characterized in that different intruders are formed at intervals to perform magnetic domain refining, and then an insulating coating treatment is performed.

In the present invention, the term "penetrable body" refers to a substance that enters a steel plate during plating, such as kl + Si *Ti
, Sb r Sr r Cu + Sn r Zn
, Fe r Ni , Cr rMn r P r S
r B * Zr + Mo * Cd * Se+
Metals such as Col Bi, nonmetals, mixtures thereof, oxides, alloys, phosphoric acid, boric acid, phosphates, borates,
Sulfates, nitrates, silicates, and mixtures thereof are used.

The term "intruder" refers to the presence of the intruder in the form of grains, lumps, or lines in the steel sheet, either alone or in combination with steel sheet components.

Heat-resistant magnetic domain refining according to the present invention can be performed as follows. That is, surface coatings such as glass coatings, oxide coatings, and insulation coatings formed on finish-annealed grain-oriented electrical steel sheets are subjected to radar irradiation, grinding, cutting, solvent, chemical polishing, pickling, corrosion, shot blasting, etc. ) The steel sheet base is exposed at intervals or entirely, and then penetrable substances such as the metals, non-metals, mixtures thereof, alloys, oxides, phosphoric acid, boric acid, etc. are added to the steel sheet. Phosphates, borates, etc. may be used in combinations thereof by electroplating, hot-dip plating, etc., if the surface coating is removed at intervals, or if it is completely removed. If so, use partial plating such as partial electroplating.
When plated with a basis weight of 05 JF/m2 or more, the penetrants react immediately with the steel sheet base, etc., and penetrants such as alloy layers and diffused substances are formed at intervals in a very short time, resulting in poor heat resistance. Certain domain subdivisions are performed very efficiently. That is, in the final annealing of a grain-oriented electrical steel sheet, a glass coating (forsterite coating) is formed by a reaction between an oxide film containing 5102 formed in the previous decarburization annealing process and an annealing separator mainly composed of MgO. ), oxide film, or phosphoric acid, aluminum phosphate, magnesium phosphate, chromic anhydride,
An insulating film formed by coating and baking colloidal silica has the effect of inhibiting the reaction when a penetrant is plated on a steel plate. For this reason, when the surface coating is removed at intervals to expose the base steel of the steel plate and plated, a reaction between the base steel and penetrants occurs selectively, and the steel composition such as an alloy layer, diffused substances, etc. Tissues and different invaders are efficiently formed. In addition, when the surface coating is completely removed and partial plating is performed at intervals, the intruders are similarly efficiently formed.

By controlling the coating weight of the plating, the amount and degree of penetration of the intruder can be easily changed, and the iron loss characteristics and magnetic flux density can be adjusted.

Next, the steel plate is treated with phosphoric acid, phosphates such as aluminum phosphate, magnesium phosphate, zinc phosphate, calcium phosphate, chromates such as chromic acid and magnesium chromate, dichromates, colloidal silica, etc. An insulating coating solution containing one or more species is applied and baked at a temperature of 350° C. or higher to form an insulating coating.

By this insulating coating treatment, the intruder formed on the steel plate is prevented from peeling off due to frictional force, slip, etc. during coil winding, and the corrosion resistance is improved to prevent the occurrence of rust. Furthermore, this baking during the insulation coating also has the effect of causing intruders to enter the steel plate.

The present invention will be specifically explained below based on an example in which a penetrant is electroplated onto a finish-annealed grain-oriented electrical steel sheet.

In the present invention, the grain-oriented electrical steel sheet that has been finish annealed is subjected to magnetic domain refining, but it is not necessary to specify the steel composition of the grain-oriented electrical steel sheet and the manufacturing conditions until finish annealing. Prisoner.

MnS + MnSe + BN, Cu2S, etc. are used as appropriate, and Cu tan, C
Contains elements such as r, Ni, Mo+Sb, etc. The slab is further hot rolled, annealed and cold rolled once or twice or more with annealing in between to obtain the final plate thickness, and then decarburized and annealed. It is also not necessary to specify the conditions for a series of processes in which the annealing is performed, an annealing separator is applied, and finish annealing is performed.

By the way, a glass coating (forsterite coating) is formed on the finish annealed grain-oriented electrical steel sheet due to the reaction between the oxide film containing SiO2 formed in the previous decarburization annealing process and the annealing separator mainly composed of oil θ. is formed. This glass coating suppresses the reaction between the penetrable body to be electroplated in the application example of the present invention and the steel plate substrate, and the oxide film slightly present under the glass coating may also impede the above reaction. Further, if an insulating coating is formed, it has the same effect as the glass coating.

Eliminating these harmful effects, the penetrable body reacts with the steel plate substrate, etc.
The glass coating, oxide coating, insulating coating, etc. on the steel plate are formed at intervals so that an alloy layer different from the steel composition or structure, and intruders such as diffused substances are efficiently and highly stably formed on the steel plate. Remove it completely or completely. To remove at intervals, use laser irradiation, grinding, cutting, solvents,
This is done by local pickling. The distance between them is 1 to 30 m),
The intervals may be equal or irregular. The direction of removal is preferably 30 to 90 degrees with respect to the rolling direction of the steel plate. The removal may be continuous or discontinuous. To completely remove it, pickling, Schottplating, etc. are used. Further, the width of removal is preferably 0.01 to 5 m for the purpose of forming intruders.

Removal of this surface coating exposes the steel plate base metal. This exposure also includes forming a slight dent in a part of the steel sheet base.

The grain-oriented electrical steel sheet is then electroplated with the penetrant.

If the surface coating is removed at intervals, penetrants such as AL, St, Ti, Sb,
Sr.

Sn, Zn, Fe, Ni, Cr*M
n + P IS, B + Zr.

Metals such as Mo, Co, Bi + Cd + Se, non-metals, mixtures thereof, oxides, alloys, phosphates, borates, sulfates, nitrates, silicates, phosphoric acid, boric acid, etc. are added. The steel plate is passed through the electrolyte solution and electroplated. During this plating, an electrical reaction occurs only at the locations where the surface coating is removed at intervals and the steel sheet base is exposed, and no such reaction occurs at other locations. Therefore, the penetrable body is plated only on the exposed portions of the steel sheet base.

Therefore, intruders such as alloy layers and diffused substances can be formed at desired locations and at desired intervals without reducing the sheet passing speed of the plating line at all. Furthermore, since the portion where the surface coating is present does not react with the electrolyte as described above, the surface coating also has the effect of being maintained in a clean state.

On the other hand, if the surface coating has been completely removed, the penetrant is plated at intervals (for example, by partial electroplating).

In this plating, the basis weight is important), and if the amount is small, there will be few intruders formed and the magnetic domains will not be subdivided. 0.0 to perform magnetic domain refinement to reduce iron loss characteristics.
05Ji/n+ is required), and plating above this basis weight will result in the formation of intrusions that are different from the structure of the steel sheet, such as alloy layers and diffused substances, which will lead to the formation of heat-resistant magnetic domains. subdivision is carried out. Furthermore, by controlling the basis weight, the depth and amount of the intruder can be changed. For example, increasing the basis weight increases the depth and amount of the intruder, and the iron loss characteristics are greatly improved. That is, by controlling the basis weight, it is possible to achieve low iron loss and to control the iron loss characteristic level. Also, the magnetic flux density (depending on the area weight) can also be changed. For example, if the basis weight increases, the magnetic flux density can be lowered while improving the core loss characteristics. Therefore, if the iron core of a transformer is manufactured using this steel plate, the actual iron loss will be greatly improved.

Next, an insulating coating solution containing phosphoric acid, phosphate, phosphate and chromate, or phosphate, chromate and colloidal silica is applied to the steel plate and baked at a temperature of 350°C or higher to form an insulating coating. form.

FIG. 1 shows a micrograph (xiooo) of an example of an intruder formed in a steel plate by applying the present invention.

It is inferred that the composition of the intruder is different from that of the steel, and its structure is also different, so many magnetic domain buds are formed on both sides of the intruder, and when the steel plate is magnetized, the magnetic domain buds extend and the magnetic domains are subdivided. be done.

Examples will be described below.

[Example 1] C: 0.078, Si: 3.35, Mn in weight%
20, 068, At: 0.026, S: 0.024
, Cu: 0.15, Sn: 0.08, balance iron was hot rolled, annealed and cold rolled by a well-known method to obtain a 0.225 m thick steel plate.

Next, the well-known steps of decarburization annealing, application of an annealing separator containing MgO as a main component, and final annealing were performed. The steel plate after final annealing was used as the "before treatment" test material. CO□ on the steel plate
Laser irradiation was applied to remove the glass coating and oxide coating at intervals of 10 m in a direction approximately perpendicular to the rolling direction, and then the first
Using an electrolytic solution containing the plating metal (penetrable body) shown in the table, the basis weight is 1f! /m2, and then apply an insulating coating solution containing aluminum phosphate, phosphoric acid, chromic anhydride, chromate, and colloidal silica.
It was baked at 50° C. to form an insulating film and was used as a “treated” test material.

Thereafter, strain relief annealing was performed at 800° C. for 2 hours to obtain a “strain relief annealed” test material.

As described above, the magnetic properties of each sample material were measured "before treatment", "after treatment J", and "after strain relief annealing".

The measurement results are shown in Table 2.

Table 1 [Example 2] c: o, oso, S i : 3.30, in weight %
Mn: 0.070, At: 0.02B, s: o, 02
5, N: 0.0080, silicon steel slag consisting of balance iron is hot rolled, annealed and cold rolled by a well-known method.
．． A steel plate with a thickness of 225 m was obtained.

Next, the well-known decarburization annealing was applied with an annealing separator mainly composed of MgO, and final annealing was performed. Thereafter, an insulating coating liquid was applied, and an insulating coating was formed by baking which also served as flattening annealing. This was used as the "before treatment" test material. This steel plate has c0
The glass coating and the insulating coating were removed at intervals of 5 m in a direction substantially perpendicular to the rolling direction, and the area weight was 0.05 to 10. OI
Electroplated at I/m. Next, an insulating coating solution containing aluminum phosphate, chromic anhydride, chromate, and colloidal silica was applied and baked at 350° C. to form an insulating coating. This was used as the "after treatment" test material.

Thereafter, strain relief annealing was performed at 800° C. for 2 hours to obtain a “strain relief annealed” test material.

Table 4 shows the results of measuring the magnetic properties of the sample materials "before treatment,""aftertreatment," and "after strain relief annealing."

These samples were also tested for time, interlayer resistance (JIS Method 2), and corrosion resistance (constant temperature, constant humidity chamber test 50'c x 24 hours humidity 98%). As a result, the interlayer current was zero in all cases, and no rust occurred.

As is clear from the above examples, the iron loss improvement effect is not lost even when strain relief annealing is performed after magnetic domain refining, and grain-oriented electrical steel sheets with extremely low iron loss and good magnetic flux density, corrosion resistance, and insulation properties are produced. provided.

〔Effect of the invention〕

As explained above, according to the present invention, the core loss of the steel plate is reduced by magnetic domain refining by the intruder, and after that,
It has an excellent feature not seen in previous magnetic domain refining methods, in that the iron loss improvement effect does not disappear even when strain relief annealing is performed at high temperatures.

[Brief explanation of the drawing]

FIG. 1 is a metal micrograph (xiooo) showing an intruder formed in a steel plate according to the present invention.

Claims (1)

[Scope of Claims] 1. Surface coatings such as glass coating and insulation coating of a finish annealed grain-oriented electrical steel sheet are removed, and the steel plate is plated with an intrusive material to a basis weight of 0.05 g/m^2 or more. A method for producing a grain-oriented electrical steel sheet with extremely excellent magnetic properties, which comprises forming interstitial bodies different from the steel composition or structure at intervals to refine the magnetic domains, and then applying an insulating coating treatment. 2. Surface coatings such as glass coatings and insulation coatings of finish annealed grain-oriented electrical steel sheets are removed at intervals, and the steel plates are plated with penetrants to a basis weight of 0.05 g/m^2 or more, A method for producing a grain-oriented electrical steel sheet with extremely excellent magnetic properties, which comprises forming interstitial bodies different from the steel composition or steel structure at intervals to refine the magnetic domains, and then applying an insulating coating treatment.