JPS62180014A - Non-oriented electrical sheet having low iron loss and superior magnetic flux density and its manufacture - Google Patents

Abstract

PURPOSE:To obtain the titled electrical sheet, by simultaneously adding small quantities of tin and copper to steel having a specified compsn. CONSTITUTION:The electrical sheet is composed of, by weight <=0.010% C, 0.1-2.0% Si, 0.75-1.5% Mn, 0.02-0.20% Sn, 0.1-1.0% Cu, <=0.005% S, (a) >0.1-0.3% acid soluble Al or (b) <=0.1% acid soluble Al, <=0.007% N, <=0.005% B under 0.5-1.5 B/N and the balance Fe. The steel is hot rolled at one time or >=2 times interposing intermediate annealing and continuously annealed. Thereafter, if necessary the sheet is skin pass rolled by 2-12% draft. Thus, by positive and effective use of tin and copper, [100] and [110] aggregate structures desirable to magnetic property can be developed and [111] aggregate structure undesirable to that can be suppressed in the aggregate structure.

Description

[Detailed description of the invention] (Field of sedentary use) The present invention relates to a non-oriented a-magnetic steel sheet with low iron loss and excellent magnetic flux density, which can be used as a core material for electrical equipment, and a method for manufacturing the same. be.

(Prior Art) In recent years, increasing the efficiency of electrical equipment has been strongly desired amidst the worldwide movement to save electricity and energy. For this reason,
Non-oriented electrical steel sheets, which are widely used as iron core materials for motors, small and medium-sized transformers, etc., are increasingly in demand for their ability to maintain high magnetic flux density and have low iron loss.

In conventional non-oriented electrical steel sheets, a method of increasing the content of Bi'(r) such as Si, % or Al has been generally used as a means to lower iron loss, from the viewpoint of reducing eddy current loss due to increased specific resistance. However, this method has the problem that the magnetic flux density decreases.

1. Not only does it increase the content of Si or Al, but it also reduces C, S, or JP-A-58-15.
1453, as well as the manufacturing process, such as increasing the annealing temperature and increasing the cold rolling reduction before final annealing. Although both methods attempted to reduce iron loss, they did not have much effect on magnetic flux density, and could not meet the demand for producing non-oriented A11 magnetic steel sheets with low iron loss and excellent magnetic flux density. .

(Problems to be Solved by the Invention) In view of the above, the present invention provides a non-oriented electrical steel sheet with low core loss and high magnetic flux density, and a method for manufacturing the same.

(Means for Solving the Problem) The present inventors have determined that the texture is desirable for magnetic properties [100] and (110) by actively utilizing a slightly accented material.
), and by suppressing the (111) texture, which is unfavorable for magnetic properties, we are conducting extensive research with the aim of obtaining non-oriented electrical steel sheets with low iron loss and high magnetic flux density. I molded it.

As a result, it was found that iron loss can be lowered and magnetic flux density can be increased by simultaneously containing Sn and Cut in a small amount in steel.

Fuzuraaki was made based on this knowledge, 3bυ,
Seven's safety is 1%, C: 0.010% lower, Si:
0.1% or more, 2.0% or less, Mn: 0.75%
Below, Cu: 0.1% or more, 1.0% or less, S: 0.0
(a) acid-soluble Al: more than 0.1% and 0.3% or less, or (b) acid-soluble Al: 0.05% or less;
Contains 1% or less, N: 0.007% or less, B: 0.005 or less, and has a B/N ratio of 0.5 to 1.5, with the balance consisting of Fe and inevitable impurity elements. Non-oriented electrical steel sheet with low iron loss and excellent magnetic flux density. Another gist is that after hot rolling, the steel containing gold is rolled and self-annealed at a temperature of 750°C or higher and 850°C or lower, or after hot rolling, it is heated at a temperature of 750°C or higher and 850°C or lower. The sheet is rolled and annealed, then cold rolled once or twice or more with intermediate annealing in between, and then continuously annealed. Still another feature is that after the continuous annealing of the cold-rolled sheet, the reduction rate is 2 to 2.
This is where skin pass rolling is performed at 12%.

The present invention will be explained in detail below.

First, the reasons for limiting the steel components of the present invention will be described.

C is a harmful component that increases iron loss, and as is well known, the original SI of magnetic aging is a component that has the effect of reducing iron loss, and in order to achieve this effect, it is safe to include it at 0.1% or more. . On the other hand, as the number of companies containing it increases, the magnetic flux density decreases as described above, rolling workability deteriorates, and the cost per fc increases, so the coefficient is set to be below 2.0.

AA is an essential component for deoxidizing, but when used for purposes other than deoxidizing, it has the effect of increasing solid resistance and lowering iron loss, similar to Si. For this purpose, it is necessary to contain more than 0.1% of Lj, and under 0.1% Lj, the magnetism deteriorates due to the formation of AlN. Moreover, when it exceeds 0.3%, the magnetic flux density decreases similarly to 81.

ktf (0.1% when used only for deoxidizing purposes)
In this case, since the magnetism deteriorates due to the production of AlH, it is safe to add it to 81 to cause the production of BNi and suppress the production of AjH. For this purpose, a B/N ratio of 0.5 to 1.5 is most effective.

Incidentally, the absolute value of B is set to be less than o, oos% in order to prevent the occurrence of cracks in the steel billet. In addition, the absolute content of N is zero in order to completely prevent the formation of AlN, which is harmful to magnetism.
．． 007% or less.

Since Mu tends to generate nonmetallic inclusions such as sulfides,
Until now, it has not been used to improve the magnetic properties of non-oriented electrical steel sheets, but the development of high-purity steel manufacturing technology has made it possible to use it. According to the findings of the present inventors, Mn develops [100] and (110) agglomerated textures that are desirable for magnetic properties, and [11] that are unfavorable for magnetic properties.
1:l Has the effect of suppressing the engrafted tissue. As proposed in Japanese Patent Application Laid-open No. 17828/1983, the content of Mn must be 0.75% or more to bring about this effect. Also,
Because Mn lowers the ferrite-austenite transformation temperature.

If the Mn content exceeds 1.5%, ferrite-austenite modification B occurs during hot-rolled sheet annealing, and the texture improving effect of Mn decreases. Therefore, the M content of Mn is 0°7
The content was set to be 5% or more and 1.5% or less.

Since S generates non-metallic inclusions such as MnS that are harmful to magnetism, it is necessary to reduce the amount to less than o, oos%.

In particular, by containing 0.75 to 1.5% of 1Mn, the ferrite-austenite transformation temperature is lowered, so it is necessary to perform sufficient recrystallization at a relatively low temperature.
For this purpose as well, it is effective to reduce the S content.

8n has the effect of lowering iron loss and increasing magnetic flux density due to its compound ownership with Cu, but in order to achieve this effect, it is safe to contain it at 0.02% or more. On the other hand, even if the content increases, its effect will be saturated, and on the contrary, it will cause negative effects such as suppression of crystal grain growth and increase costs, so it is 0.
20% or less.

Cu lowers iron loss by combining with Sn mentioned above,
It has the effect of increasing the magnetic flux density, but in order to achieve this effect, it is safe to contain it at 0.1% or more.

On the other hand, even if this content increases, it may cause hot embrittlement, etc., resulting in poor workability.
Since problems arise in processability, the content should be 1.0% or less.

Components other than those mentioned above are iron and unavoidable impurity elements.

Next, the combined effect of Sn and Cu, which is a feature of the invention, will be explained.

Figure 1 shows the steel slabs shown in Figure 1-& after being hot-rolled, coiled at a temperature of 830°C, self-annealed, and then cold-rolled to a thickness of 0.47m. Continuous finish annealing was performed at a temperature of 850°C for 40 seconds, and then the Epstein sample was cut and strain relief annealed at 790°C for 1 hour.
These are the results of measuring magnetic properties. Compared to steel ■ containing neither Sn nor Cu, steel ■ containing only Sn
, and steel (2) containing only Cu, a decrease in iron loss is observed.

However, steel ■ with a composite of Sn and Cu has an even lower core loss of -J- than steel ■ and steel ■, which is much greater than simply adding the effects of Sn alone and Cu alone. The effect of reducing iron loss in thickness is observed. Moreover,
The magnetic flux density can also be seen. In other words, in the case of steel (2) containing only Cu, the magnetic flux density slightly decreases, whereas in the case of steel (2) containing only Cu,
In the case of steel with a composite of n and Cu, Sn and Cuf:
Steel that is not stored at all■ and steel that only contains Sn■
The magnetic flux density is further increased, and the tabletop effect of Sn and Cu is clear.

As described above, the feature of the present invention is that by containing Sn and Cu at the same time, a non-oriented electrical steel sheet with low iron loss and high magnetic flux density can be manufactured by the combined effect of the two.

(effect) Next, the manufacturing method of the present invention will be explained.

Steel made of the above components is melted in a converter or electric furnace, and is made into a slab by continuous casting or by ingot forming and then blooming rolling.

The coil is then hot-rolled. In this hot rolling, the coil is wound 9 at a temperature of 750° C. or higher and self-annealed using the heat possessed by the hot-rolled coil. During this self-annealing, it is convenient to cover the hot-rolled coil with a heat-retaining cover that prevents radiation of heat. in this case.

When the winding temperature is less than 750° C., the combined effect of Sn and Cu is small, and the effect of lowering iron loss and increasing magnetic flux density is small. In addition, since it contains 0.75 to 1.5% Mn, the effect tends to disappear due to ferrite-austenite transformation at temperatures above 850°C.In addition, in hot rolling, rolling at temperatures above 750°C Instead of self-annealing, the hot-rolled sheet is annealed at a temperature of 750° C. or more and 850° C. or less after hot rolling. This also reduces iron loss due to the combined effect of Sn and Cu (D"d),
Although the magnetic flux density can be increased, the effect is small if the hot rolled sheet annealing temperature is less than 750°C. Also, Mn is 0.7
By containing 5 to 1.5%, ferrite-austenite transformation occurs at temperatures exceeding 850°C, and the effect tends to disappear.

Next, the plate is cold rolled once or twice or more with intermediate annealing in between to obtain a predetermined plate thickness.

Then, below the ferrite-austenite transformation temperature,
+Il) Continuous finish annealing for crystal and grain growth.

With the above steps, a non-oriented electrical steel sheet is produced.Next, it is subjected to a skin basket reduction of 2 to 12%, and then punched into a predetermined shape and subjected to a temporary strain relief annealing. Magnetic copper plates are manufactured.

The reason why the rolling blockage in skin pass rolling is 2 to 12% is 2.
If it is less than 12%, it is difficult to obtain good magnetic properties during strain relief annealing, and the reason why the upper limit is set to 12% is because if it exceeds this, the magnetic properties will deteriorate.

(Implementation fl) Next, examples of the present invention will be shown.

Example 1 Steel having the components shown in Table 2 was manufactured under the treatment conditions shown in the same table, cut into Epstein samples, subjected to strain relief annealing at 790° C. for 1 hour, and magnetic properties were measured. The measurement results are also shown in the same table. Through non-invention, we have been able to manufacture non-oriented electrical steel sheets with extremely low iron loss and high magnetic flux density.
It is clear that he is capable of this.

The following is a crossmill example 2 Steel A11.12, 13゜14 used in the above-mentioned Eishi 91''1
．． 15 was cold rolled to a thickness of 0.50+m and rolled at 850°C x 40
Continuous annealing was performed for 2 seconds, followed by skin rolling with a reduction of 6% to give a thickness of 0.47 m+a. Thereafter, it was cut into Epstein samples, subjected to strain relief annealing at 790° C. for 1 hour, and the magnetic properties were measured. The measurement results are shown in Table 3. It is clear that according to the present invention, it is possible to manufacture a non-oriented electrical steel sheet with extremely low iron loss and high magnetic flux density.

Table 3 (Effects of the Invention) As described above, according to the present invention, a non-oriented electrical steel sheet with low core loss and high magnetic flux density can be obtained, and with the increasing efficiency of electrical equipment, it has become popular as a core material for electrical equipment. It can fully meet the requirements for the non-oriented electrical steel sheets used, and its industrial effects are extremely significant.

[Brief explanation of drawings]

Figure 1 shows the iron loss W of comparative materials (■ to ■) and the present invention material (■).
15150 and a diagram showing the relationship between magnetic flux density B5o.

Claims (1)

[Claims] 1. In weight%, C: 0.010% or less, Si: 0.1%
or more, 2.0% or less, Mn: 0.75% or more, 1.5%
Hereinafter, Sn: 0.02% or more and 0.20% or less, Cu:
0.1% or more and 1.0% or less, S: 0.005% or less, (a) acid-soluble Al: more than 0.1% and 0.3% or less, or (b) acid-soluble Al: 0 .1% or less, N:
0.007% or less, B: 0.005% or less, and the weight ratio B/N with N is 0.5 to 1.5, and the balance is Fe and inevitable impurity elements. Low iron loss and magnetic flux density. Superior non-oriented electrical steel sheet. 2. In weight%, C: 0.010% or less, Si: 0.1%
or more, 2.0% or less, Mn: 0.75% or more, 1.5%
Hereinafter, Sn: 0.02% or more and 0.20% or less, Cu:
0.1% or more and 1.0% or less, S: 0.005% or less, (a) acid-soluble Al: more than 0.1% and 0.3% or less, or (b) acid-soluble Al: 0 .1% or less, N:
After hot rolling, a steel containing 0.007% or less, B: 0.005% or less, and a weight ratio of B/N with N of 0.5 to 1.5, with the balance consisting of Fe and unavoidable impurity elements. 750℃
Low iron loss and excellent magnetic flux density characterized by rolling and self-annealing at a temperature of 850°C or less, followed by cold rolling once or twice or more with intermediate annealing, and continuous annealing. A method for producing a non-oriented electrical steel sheet. 3. Non-directional with low core loss and excellent magnetic flux density as claimed in claim 2, characterized in that after continuous annealing after cold rolling, skin pass rolling is performed at a rolling reduction of 2 to 12%. Manufacturing method of electrical steel sheet. 4. In weight%, C: 0.010% or less, Si: 0.1%
or more, 2.0% or less, Mn: 0.75% or more, 1.5%
Hereinafter, Sn: 0.02% or more and 0.20% or less, Cu:
0.1% or more and 1.0% or less, S: 0.005% or less, (a) acid-soluble Al: more than 0.1% and 0.3% or less, or (b) acid-soluble Al: 0 .1% or less, N:
After hot rolling, a steel containing 0.007% or less, B: 0.005% or less, and a weight ratio of B/N with N of 0.5 to 1.5, with the balance consisting of Fe and unavoidable impurity elements. 750℃
A hot-rolled sheet annealed at a temperature of 850℃ or less, then cold rolled once or twice or more with intermediate annealing, and then continuously annealed. A method for manufacturing non-oriented electrical steel sheets. 5. Non-directional with low iron loss and excellent magnetic flux density as claimed in claim 4, characterized in that after continuous annealing after cold rolling, skin pass rolling is performed at a rolling reduction of 2 to 12%. Manufacturing method of electrical steel sheet.