JPS61190902A - Directional electromagnetic steel plate of very low iron loss - Google Patents

Abstract

PURPOSE:To obtain the directional electromagnetic steels plate of very low iron loss by a method wherein a magnetic domain is fractionized by allowing a proper substance to penetrate. CONSTITUTION:When a penetrating substance (an alloy layer, a diffusion layer, a surface reaction produce obtained by the reaction with a steel plate and a surface film, for example) having the width of 5mm or less which is different from the steel component or the steel construction of a directional electromagnetic steel plate, enters an annealing-finished directional electromagnetic steel plate leaving an interval of 1mm or more, the magnetic domain of the steel plate is fractionized. The iron loss is very small, and the directional electromagnetic steel plate whereon the iron loss improvement effect by the fractionization of magnetic domain does not vanish even when the heat treatment such as a distortion-removing annealing and the like is performed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a grain-oriented electrical steel sheet with extremely low core loss.

[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 directional electromagnetic control plate utilizes the secondary recrystallization phenomenon, and develops secondary recrystallized grains with the (110) plane on the rolling 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 the magnetic domain becomes larger because the domain wall penetrates the grain boundary, so there is a phenomenon in which the iron loss does not decrease even though the orientation is increased. be.

As a technique for eliminating this phenomenon and reducing iron loss, there is, for example, Japanese Patent Publication No. 58-5968. This is done by pressing small balls etc. on the surface of the unidirectional electrical steel sheet after final finish annealing to form a dent of 5μ or less in depth and applying a linear minute strain to differentiate the magnetic domains and reduce iron loss. It is something that can be improved. In addition, Japanese Patent Publication No. 58-26410 discloses that at least one trace of laser irradiation is formed 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. 58-264
According to the method shown in No. 10, iron quality is improved by applying local minute strain to the surface of a unidirectional electrical steel sheet,
Ultra-low core loss material can be obtained.

[Problem that the invention seeks to solve]

However, even if the ultra-low iron loss material obtained as described above is annealed at high temperature, the iron loss improving effect is lost.For example, there is a problem that the iron loss improving effect disappears during strain relief annealing when manufacturing a wound core. .

In addition, as a means to reduce the iron loss of grain-oriented electrical steel sheets,
It is known to reduce the thickness of the steel plate and to reduce the crystal grain size. However, when the plate thickness is made thinner, secondary recrystallization becomes less likely to occur, and in order to stably cause secondary recrystallization on an actual manufacturing line, much consideration must be given to the manufacturing method. Also, as the plate thickness decreases, the eddy current loss decreases,
On the other hand, since the hysteresis increases, there is a limit to the reduction in iron loss.

Although grain refinement has a certain effect on reducing iron loss, a large reduction in iron loss is not expected.

The present invention can stably obtain a grain-oriented electrical steel sheet with extremely low core loss (regardless of plate thickness), and also has low core loss even when strain relief annealing is performed at 700 to 900°C as in the production of wound iron cores, for example. The aim is to obtain ultra-low iron loss grain-oriented electrical steel sheets that do not deteriorate.

The present inventors conducted many experiments and conducted studies in order to achieve the above object.

[Means for solving problems]

As a result, we found that intrusions of 5 mm or less in size that differed from the steel composition or steel structure of the finish annealed grain-oriented electrical steel sheet (
For example, if an alloy layer, diffused material, or surface reaction product formed by reaction with a steel plate or surface coating is formed by infiltrating it at intervals of 1 mm or more, the magnetic domain will be subdivided, the iron loss will be extremely low, and after that, strain relief annealing will be required. It has been found that a grain-oriented electrical steel sheet can be obtained in which the iron loss improvement effect due to magnetic domain differentiation does not disappear even when heat treatment is applied.

The present invention was made based on this knowledge, and is characterized by the fact that an intruder with a width of 5 mm or less different from the base iron composition or steel structure of the steel sheet is added to a finish annealed grain-oriented electrical steel sheet. It is a grain-oriented electrical steel sheet with extremely low core loss, in which magnetic domains are subdivided at intervals of 1 mm or more.

In the present invention, the term "intruder" refers to a coating on a steel sheet that forms grains, lumps, or lines in the steel sheet, either alone or in combination with components on the steel sheet side including other coatings, or even with cloud surrounding air components. It expresses the state of being. In the present invention, the term "coating" refers to a mechanical coating film of a reintrusion body formed on at least a portion of a steel plate, a chemically attached film or adhesive such as plating, and a film partially having a reaction layer. It is a general term that includes all such things. A re-invader refers to a substance that can form an intruder.The present invention will be described in detail below.

The finish annealed grain-oriented electrical steel sheet to which the present invention is applied is
There is no need to specify the steel composition and manufacturing conditions up to final annealing; for example, A I N+ as an inhibitor.
Appropriate materials such as MnS, MnSe+ BN+ CuzS are used, and Cu, Sn, Cr, etc. are used as necessary.
Ni, Mo.

contains elements such as sb, and further hot-rolls the slab,
It is also necessary to specify the conditions of a series of processes in which the plate is annealed and cold-rolled once or twice or more to achieve the final thickness, decarburized annealed, coated with an annealing separator, and finished annealed. There isn't.

Next, we will expand on the experimental data.

The test material had a weight percentage of C: 0.075%, S t : 3,
30%, Mn: 0.072%, S: 0.02
4%, Al: 0.028%, N: 0.008
A silicon steel slab containing 0% was processed in a known manner from slab heating to final annealing. The final thickness is 0.
It is 027mm. The finish annealed grain-oriented electrical steel sheet was subjected to heat flattening and insulating coating baking, and then the SB powder of the re-intrusion body was applied as a slurry-like agent at 20 g/HzO 50 cc in various amounts, approximately in the rolling direction of the steel sheet. It was applied at right angles. The interval between applications is 1 to 30
mm, irradiate the area to be coated with a laser in advance,
The insulation coating was removed. The length of the scar caused by the laser irradiation at this time was 0.2 mm. After drying 800℃ x 0.5 hours 90%N! Heat treatment is performed in an atmosphere of +10% Hz, and the chemical reacts with the steel plate, its surface coating, or atmospheric gas, causing intruders such as alloy layers, diffused substances, and surface reaction products to enter the steel plate at intervals. The width of the intruder was varied by changing the amount of coating (during application of the coating agent). Thereafter, annealing was performed at 800° C. for 4 hours in accordance with strain relief annealing.

For this test material, the iron loss WI7/10 was measured after finishing annealing and baking the insulation coating (before treatment) and after forming the intruder (after treatment), and from these values, the width of the intruder was determined by the following formula. The influence on loss improvement ΔW was investigated.

6mmw’,,,SO-w”,,,S.

However, W' I? Is 15° the iron loss WI before treatment? /S.

W! +//. is the iron loss W+7/s after treatment.

The results are shown in FIG. As seen in this figure, it has been found that the formation of the interstitial bodies subdivides the magnetic domain and improves iron loss, and this effect is achieved when the width of the interstitial bodies is 5 mm or less. If it exceeds 5 mm, the iron loss improvement effect will be lost.

The width of the intruder was measured at or near the surface of the steel plate.

Such an effect is not limited to those having the steel composition used in the test material, but also Cu, Sn, Sb, Mo, Cr,
Ni.

It is also found in those containing one or more elements such as Se.

As mentioned above, the core loss is reduced by the formation of the intruder, but if the width of the intruder becomes large, the differentiation of magnetic domain groups is weakened and it is not possible to reduce the core loss. Therefore, in the present invention, the width of the intruder is set to 5 mm or less. In addition, it is necessary to form the penetrating bodies at intervals, and the narrower the interval, the less the decrease in iron loss.
mm or more.

This interval is preferably determined in relation to the width of the penetrator.

The depth of the intruder entering the steel plate may be 2 μm or more.

Further, the iron loss improvement (reduction) due to the formation of the interstitial bodies has an excellent effect in that it does not disappear even after strain relief annealing at a high temperature.

The re-penetrating body for forming the penetrating body is not limited to the above-mentioned sb, but any substance that reacts with the steel plate, its surface coating, etc. or enters the steel plate alone can be used. For example, Aj! , St.

Sr, Cut Sn, Zn+ Fe, Nt+ C
r, Mn+P, StB+Mo.

Zr, Co, their oxides, mixtures, alloys, phosphoric acid, boric acid, phosphates, borates, sulfates, silicates, etc. are used.

Further, the method of coating the surface of the steel plate with the reintrusion material may be any of coating, plating, vapor deposition, adhesion, welding, etc.

In addition to the heat treatment described above, methods such as plating, chemical conversion treatment, and local high-frequency heating may be used to form the intruder.

Furthermore, in order to promote the formation of intruders, surface coatings such as glass coatings and insulating coatings are removed, strain is applied, and the like.

FIG. 2 shows a microscopic structure photograph (X100O) of an example of an intruder formed in a steel plate by applying the present invention.

Examples will be described below.

Example weight %: C: 0.081, S i: 3.22,
Mn: 0.071, Aj! :0.02B,S
:0.024, Cu:0.08, Sn:0.14
A silicon steel slab consisting of the remainder iron was hot rolled, annealed, and cold rolled by a well-known method to obtain a steel plate having a thickness of 0.250 mm.

Next, the well-known steps of decarburization annealing and optional annealing with application of an annealing separator were carried out. This finish annealed steel plate was used as a "before treatment" test material. The surface coating was removed at 5 mm intervals by irradiating the finish annealed steel plate with a CO2 laser, and then the chemicals shown in Table 1 were coated and applied in different widths to a weight of 5 g/m'' after drying. 750 after drying
A heat treatment was performed in an atmosphere of N2 for 1 hour at ℃ to form an interstitial body. This was used as the "after treatment" test material. After this, strain relief annealing was further performed at 800° C. for 4 hours to obtain a "after strain relief annealing" test material.

The magnetic properties of each sample material were measured ``before treatment'', ``after treatment'', and ``after strain relief annealing''.

The measurement results are shown in Table 2.

As is clear from the above examples, the present invention provides grain-oriented electrical steel sheets with extremely low iron loss. Furthermore, even if strain relief annealing is performed thereafter, the iron loss improving effect due to magnetic domain group differentiation is not lost, which is an extremely excellent effect.

〔Effect of the invention〕

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

[Brief explanation of drawings]

Figure 1 is a diagram showing the influence of the width of the intruder on iron loss improvement.
FIG. 2 is a metal micrograph (X100O) showing an intruder formed on a steel plate according to the present invention. Figure 1 Width of intruder (mm)

Claims (1)

[Claims] A 1 mm intruder with a width of 5 mm or less that is different from the steel composition or steel structure of the steel sheet is added to a finish annealed grain-oriented electrical steel sheet.
A grain-oriented electrical steel sheet with extremely low iron loss that is formed by inserting the magnetic domains at the above-mentioned intervals to differentiate the magnetic domains.