JPS61117222A - Production of ultra-low iron loss grain-oriented electrical steel sheet - Google Patents

Abstract

PURPOSE:To produce efficiently an ultra-iron loss grain-oriented steel sheet with economized energy by forming a film of an infilterative body to the grain- oriented electrical steel sheet subjected to finish annealing then heating the steel sheet by thermal irradiation and forming the infiltrated body at intervals. CONSTITUTION:The film of the infilterative body of a metal, non-metal, etc. is formed by painting, plating, etc., on the grain-oriented electrical steel sheet subjected to finish annealing. The steel sheet formed with the film is thermally irradiated by a pulse laser, etc. and is intermittently heated after drying of the film. The infilterative body is thereby brought into reaction with the steel sheet or the surface film thereof, etc., and the infiltrated body consisting of the alloy, result product of reaction, diffused body, etc., having the steel component or structure different from the component or structure of ferritic steel sheet is formed at intervals in the form of intruding into the sheet thickness direction. The magnetic domains are thus finely segmented without the loss of the effect of improving the iron loss even after the heat treatment such as stress relief annealing. The grain-oriented electrical steel sheet having extremely low iron loss is obtd.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing an ultra-low core loss grain-oriented electrical steel sheet.
More specifically, the present invention relates to a method for providing a grain-oriented electrical steel sheet with extremely low core loss through magnetic domain refining that does not lose its core loss improving effect even after heat treatment.

(Prior Art) 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 grain-oriented electrical steel sheet utilizes the secondary recrystallization phenomenon and develops a secondary recrystallized grain structure with the (110) plane on the rolled surface and the <001> axis in the rolling direction, which is the so-called Goss orientation. . By increasing the degree of integration of the (110) <001> orientation and reducing deviation from the rolling direction as much as possible, products with excellent excitation characteristics, iron loss characteristics, etc. can be 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, and the iron loss increases even though the degree of integration increases. There is a phenomenon where it does not get lower.

For example, there is Japanese Patent Publication No. 58-5968 as a technique for eliminating the above-mentioned phenomenon and reducing iron loss. This is done by pressing small balls etc. onto the surface of a unidirectional electrical steel sheet that has undergone final finish annealing to form concavities with a depth of 5μ or less and applying linear microstrain to subdivide the magnetic domains. It is intended to improve losses. Furthermore, Japanese Patent Publication No. 58-26410 discloses a method of forming at least one trace by laser irradiation on the surface of each crystal grain of secondary recrystallization generated by final finish annealing to subdivide the magnetic domain and reduce iron loss. Proposed.

These Special Publications No. 58-5968 and Special Publication No. 58-
According to the method disclosed in No. 26410, 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.

(Problems to be Solved by the Invention) However, when the ultra-low core loss material obtained as described above is annealed, the effect of improving core loss is lost. For example, there is a problem that the iron loss improving effect disappears in strain relief annealing when manufacturing a wound core.

The object of the present invention is to efficiently and energy-savingly obtain grain-oriented electrical steel sheets with extremely low core loss by performing magnetic domain refining that does not eliminate the core loss improvement effect even after heat treatment, such as stress relief annealing.

The present inventors performed strain relief annealing after magnetic domain refining, for example, at 700°C.
Many experiments were conducted to produce a grain-oriented electrical steel sheet with extremely low core loss through magnetic domain refining that does not lose its core loss improvement effect even when heat treated at temperatures of ~900°C.

(Means for Solving the Problem) As a result, finish-annealed grain-oriented electrical steel sheets have an intruder that differs from the steel composition or structure of the steel sheet, such as an alloy layer or a surface coating due to reaction with the steel sheet or surface coating. When reaction products, diffusers, etc. are formed by entering the steel plate at intervals, magnetic domain buds are generated on both sides, and when the steel plate is magnetized, the magnetic domains are subdivided, and then heat treatment such as strain relief annealing is performed. It has been found that the iron loss improvement effect due to magnetic domain refinement does not disappear even if the magnetic domain refinement is applied, and grain-oriented electrical steel sheets with extremely low iron loss can be obtained.

The present invention relates to a method for efficiently and energy-savingly providing grain-oriented electrical steel sheets with ultra-low core loss.
The feature is that a film of penetrants is formed on a grain-oriented electrical steel sheet that has been finish annealed, and then the steel sheet is heated by thermal irradiation, so that the steel sheet base material is applied to the steel sheet. The present invention provides a method for producing ultra-low iron loss grain-oriented electrical steel sheets, which is characterized by forming intruders different from the steel composition or steel structure at intervals to perform magnetic domain refining.

In the present invention, an "intruder" refers to a coating on a steel plate that exists in the steel plate as grains or lumps, either alone or in combination with components on the steel plate including other coatings, and even with atmospheric components. It expresses the situation. A penetrant refers to a substance that can form a penetrant.

In the present invention, "coating" is a general term that includes all mechanical coating films, chemical adhesion films such as metal coatings, or adhesives on at least a portion of the steel plate, and films that partially have a reaction layer. , and its thickness is also not specified.

This heat-resistant magnetic domain subdivision can be performed as follows.

Therefore, the finish annealed directional electromagnetic plate is coated with penetrable substances such as metals, nonmetals, mixtures thereof, alloys, oxides, phosphoric acid, boric acid, phosphates, borates, etc. The chemical mixture is coated by various methods such as coating, plating, vapor deposition, adhesion, welding, and corrosion, and then the steel plate is heated by thermal irradiation such as laser irradiation or electron beam irradiation, thereby eliminating penetrants. reacts with the copper plate and its surface coating,
Intruders that are different from the steel composition or steel structure of the base steel sheet are formed at intervals by penetrating into the steel sheet, resulting in heat-resistant magnetic domain refining. A specific example of the substance forming the intruder will be described later, but any substance that reacts with the steel plate or its surface coating upon heating by thermal irradiation and invades the steel plate may be used.

The present invention will be specifically explained below based on an example in which a finish annealed grain-oriented electrical steel sheet is coated with a chemical to form a film, and then thermally irradiated.

In the present invention, the finish annealed grain-oriented electrical steel sheet is subjected to magnetic domain refining, but the steel composition of the grain-oriented electrical steel sheet and the manufacturing conditions until finish annealing do not need to be specified; for example, An is used as an inhibitor.

M n S + M n S e + B N + C
An appropriate one such as u t S is used, and if necessary, C
u + S n + Cr + N i + Mo +
Sb and other elements are contained, and the slab is further hot-rolled, annealed and cold-rolled once or twice or more with annealing to achieve the final thickness, decarburized annealed, and annealed with an annealing separator. There is no need to specify the conditions for the series of processes in which the material is applied and finish annealed.

By the way, in this example, where a chemical is applied to the entire surface or at intervals to form a film on a grain-oriented electrical steel sheet that has been finish annealed, the chemicals for the penetrant include All, Si,
Ti, Sb, Sr, Cu, Sn+ Zn, F
Metals such as e, Ni+Cr, Mn, S, B, nonmetals, mixtures thereof, oxides, alloys, phosphoric acid, boric acid, phosphates, borates, sulfates, nitrates, silicates, etc. A mixture of these is used, and a coating is formed by coating the mixture in the form of a slurry or solution.

In the drug, metals, nonmetals, their oxides, and alloys are preferably used in powder form. When using powders of metals, nonmetals, their oxides, or alloys as a slurry, it is easier to apply by suspending them in water, so the amount of metal, etc. should be approximately 2 to 100 parts by weight per 100 parts by weight of water. to a concentration of

When metals, non-metals, or their oxides or alloys are used in combination with acids or salts, they may be applied as a undiluted solution or diluted with water to an appropriate concentration.

The amount of these chemicals applied to form the film is 0 per area of the steel plate.
．． It is sufficient if it is in the range of 1 to 50 g/td.

Next, after drying, the grain-oriented electrical steel sheet on which the film was formed was
For example, pulsed lasers or electron beams with high irradiation energy are used for thermal irradiation, which heats the steel plate at intervals. As a result of the reaction, intruders such as alloy layers, surface reaction products, and diffusers different from the steel composition or structure of the steel base steel are formed at intervals in the thickness direction of the steel plate.

The spacing between these thermal irradiations is 1 to 30, and the spacing between adjacent ones may be equal or different.

The present invention is an example of an intruder formed by applying a microscope U.
A photograph (X 1000) of the fabric is shown in Figure 1. In this diagram, A
The marked object is the intruder, and it is observed that it has entered the steel plate in the thickness direction.

(Example) Next, an example will be described.

C: 0.078%, Si: 3.27%, M
n: 0.073% AJ: 0.029%, S
: 0.024%, Cu: 0.16%Sn
: A silicon steel slab containing 0.008% was hot-rolled, hot-rolled plate annealed, and cold-rolled to a thickness of 0.225 mm by a known method.

Next, a sample with a width of IQ cm and a length of 50 cm was cut out from the coil that had been subjected to decarburization annealing, application of annealing separation agent, and final annealing, and strain relief annealing was performed at 800°C for 4 hours to remove strain and coil cent, and then the magnetic properties were measured. did. (Soda) A solution containing 10 g of each drug listed in Table 1 at a ratio of 150 ml of HzO was applied to this steel plate and dried to form a film. Next, an electron beam is irradiated at intervals of about 20 degrees to give a heating effect.
It was heated for 20 minutes at ℃ and its magnetic properties were measured. (2) Strain relief annealing was further performed at 800° C. for 3 hours, and the magnetic properties were measured. (3) These results are shown in Table 2.

As is clear from the examples shown in Tables 1 and 2, even if strain relief annealing is performed after magnetic domain refining, the iron loss improving effect is not lost, and a grain-oriented electrical steel sheet with extremely low iron loss is provided.

(Effects of the Invention) As explained above, according to the present invention, the iron 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 (X100O) showing an intruder formed in a steel plate according to the present invention. Ha

Claims (1)

[Claims] 1. A coating of penetrants is formed on a grain-oriented electrical steel sheet that has been finish annealed, and then the steel sheet is heated by thermal irradiation. A method for producing an ultra-low iron loss grain-oriented electrical steel sheet, characterized by forming interstitial bodies different from the steel composition or steel structure at intervals to refine magnetic domains. 2. A film of penetrants is formed on a finish-annealed grain-oriented electrical steel sheet, and then the steel sheet is thermally irradiated and heated at intervals, so that the steel composition of the base steel or A method for producing an ultra-low iron loss grain-oriented electrical steel sheet, which comprises forming interstitial bodies different from the steel structure at intervals to refine magnetic domains.