JPS5884924A - Production of electrical steel plate utilizing warm rolling - Google Patents

Abstract

PURPOSE:To obtain an electrical steel plate of improved magnetic flux density with one time of treatment wherein rolling-annealing are combined by generating intensive dyamical strain aging with the steel of a sufficient solid soln. (C+N) in a specific temp. region then subjecting the same to recrystallization annealing. CONSTITUTION:Steel of >=10ppm solid soln. (C+N) is rolled at >=20% draft at 200-500 deg.C; thereafter the steel is subjected to recrystallization annealing. Then the degree of integration of the (110)[001]bearing components in the crystal structure is increased thoroughly and an electrical steel plate having high magnetic density is obtained. Here, if the solid soln. (C+N) is below 10ppm, the degree of dynamical strain aging is small and no effect is expected. If the rolling temp. is below the lower limit, the diffusion transfer of C, N atoms to dislocation is slow and no sufficient dynamical strain aging is generated. In excess of the upper limit, the C and N atoms can arrive easily at dislocation but the mutual effect between the dislocation and the C, N atoms is weak and the dynamical strain aging annihilates. If the draft is below 20%, the propagation rate of the dislocation during rolling is small and the intensive dynamical strain aging is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a process based on rolling and annealing (11
The present invention relates to a new method for producing electrical steel sheets that fully develops the 0) (001) orientation and satisfies both the improvement of magnetic flux density and the reduction of iron loss.

In magnetic steel sheets, (110) is used to improve magnetic flux density.
It is already well known that steel sheets with a high concentration of (001) orientations are preferable, but in the production of this type of steel sheet, conventionally, the combination of cold rolling and annealing is repeated twice, and the second The (110) (001) orientation is developed through the process of extremely coarse grain growth at the annealing stage.

In this conventional method, a combination of cold rolling and annealing is performed twice, which consumes a large amount of energy in the manufacturing process. On the other hand, in one combination of cold rolling and annealing, high (110) (001
) could not be obtained. On the other hand, if the present invention is applied, (110) (
001) obtained.

That is, in the present invention, steel having a solid solution (C and N) of 10 ppm or more is rolled at a reduction rate of 20 inches or more in a temperature range of 200 to 500°C, and then recrystallized annealed to improve the texture. The gist of the method is to produce an electrical steel sheet characterized by developing the (110) (001) orientation component.

The contents of the present invention will be explained in detail below.

The present invention produces severe dynamic strain aging in the rolling stage prior to annealing, and utilizes the resulting special processed structure to create (11.0) (:001) texture after annealing.
) The aim is to increase the azimuth component. Dynamic strain aging is strain aging during processing that is caused by the interaction between dislocations that move during processing and solid solution C and N in the steel. According to the results of detailed research related to the present invention, when severe dynamic strain effects occur during rolling, band-shaped regions with especially large working strains (hereinafter referred to as deformation bands) are formed within grains, and during annealing Sometimes (110)[001] recrystallization nuclei are preferentially formed in the deformation zone, and (110)(001) in the texture after annealing.
Contributes to an increase in the azimuth component.

In order to produce such dynamic strain aging, the steel must first contain a sufficient amount of solid solution (C+N), and the steel must contain a sufficient amount of solid solution (C+N) before rolling. It is necessary that the amount of dissolved (C'+N) is 10 ppm or more. When the solid solution (C+N) is less than 10 ppm, the degree of dynamic strain aging is small and the effects of the present invention cannot be expected.

Next, regarding the rolling temperature, at temperatures below 200°C, the diffusion of C and N atoms in the steel is slow (and the time required for C1N atoms to diffuse and move toward dislocations is long (too much time is required, and dynamic strain aging occurs). In addition, in the temperature range exceeding 500℃, C
, H diffusion is sufficiently fast<C, N atoms can easily reach dislocations, but the interaction between dislocations and C, N atoms is weak, and dynamic strain aging disappears. Therefore, the rolling temperature is 200-500
℃ range, that is, the range of warm rolling (hereinafter referred to as hot rolling).

Further, if the rolling reduction ratio during rolling is less than 20%, the amount of multiplication of dislocations during rolling is small, and therefore dynamic strain aging does not occur violently and is not effective. For this reason, the rolling reduction ratio must be 20% or more. Since the effects of the present invention are manifested by recrystallization after rolling, it is necessary to perform recrystallization annealing under conditions that cause recrystallization after rolling under the above conditions.

It is sufficient for the steel material used to carry out the present invention to contain 10 ppm or more of solid solution (C+N), and there is no need to add other special elements. However, due to the need to improve electromagnetic properties such as iron loss value, even if a large amount of commonly added alloying elements such as A1 and Si are added, for the reasons described below, 10 ppm
It is possible to have the above solid solution (C+N), and the effects of the present invention will appear. That is, when Al is added, the solid solution N decreases or disappears because the N atoms are fixed as AIN, but it is easy to increase the solid solution C to 10 ppm or more.

Furthermore, as is well known, when a large amount of Si is added (up to several Si), the amount of solid solution (C+N) does not change significantly.

Hot rolling under the conditions specified in the present invention is effective even if it is performed in combination with other rolling, that is, a combination of hot rolling-hot rolling, hot rolling-cold rolling, or hot rolling-hot rolling and cold rolling. However, in this case, it is desirable that the rolling reduction in cold rolling is equal to or lower than that in hot rolling.

Example 1 Vacuum melted steels with different CXN contents were heated at 1200°C.
The sheet was hot rolled to a thickness of 2.0 Ill at a finishing temperature of 950°C, and then cooled in air. Table 1 shows the chemical composition of these samples and the amount of solid solution (C+N) evaluated by the internal friction method.

Table 1 Other elements in all samples are as follows.

St≦0.01, ■=o, oi%, P=0.002chi, S=0.004%, A1-〇, 002%, remainder Fe0
These samples were heated at room temperature to 70 qb at a reduction rate of 10 to 80 qb.
After rolling at a temperature of 0°C and recrystallization annealing at 700°C for 5 minutes, an X-ray pole figure was created for each sample, and the (110) (001) orientation component intensity ratio (random texture) was The X-ray reflection intensity ratio (based on the case of a standard sample) was determined.

The relationship between this (110) '(001) intensity ratio, components, and process conditions is shown in FIGS. 1 and 2.

It is clear from Figure 1 that the solid solution (C+N) is 10 P.
When a sample with Pm or more is hot rolled (rolling temperature 370°C) at a rolling reduction of 20 inches or more, (110) (001) after annealing
The intensity ratio becomes significantly higher. (A in the figure; reduction car 70%, B
: The rolling reduction was 30 inches; C: The rolling reduction was -10 inches. ) On the other hand, FIG. 2 showed that hot rolling at 200 to 500°C (reduction ratio of 50 inches) contributed to a significant increase in the (110)(001) strength ratio. (a in the figure; sample x6 of the present invention material
, b: Shows sample shop 1 of comparative material. ) Example 2 Using sample A2 and Al in Table 1, at room temperature to 700°C
After rolling 75% of each sample separately at each temperature to obtain a plate thickness of 0.5 mg, recrystallization was completed by annealing at 700°C for 5 minutes, and the electromagnetic properties of each sample in the rolling direction were measured. The results are shown in FIGS. 3 and 4.

As is clear from the figure, when the present invention material a (sample shop 7) is rolled under the present invention conditions (200 to 500°C) (rolling reduction rate 7
5%, plate thickness 0.5 mg), comparative material b (sample A2
), high magnetic flux density and low core loss values were simultaneously obtained in the rolling direction, and the electromagnetic properties were significantly improved.

Example 3 C: 0.050%, Si: 2.90%, Mn: 0
．． 086chi, S: 0.025%, Sol, Al: 0
．． Steel having a chemical composition of 0.027% and N: 0.0071% was melted and heated to 1300°C, then hot rolled to a thickness of 2.0 m at a finishing temperature of 970°C, and then heated at 400°C during air cooling. Rolling of 75 inches each was carried out separately at room temperature.
The plate thickness was 5 mm.

After that, recrystallization is completed by annealing at 800°C for 5 minutes.
The electromagnetic characteristics in the rolling direction were measured.

The results are shown in Table 2. However, the solid solution (C+N) just before 75% rolling is 40% as measured by the internal friction method.
83 ppm just before rolling at 0°C.

It was 72 ppm immediately before rolling at room temperature.

As is clear from the table, in the material of the present invention, high magnetic flux density and low core loss values are simultaneously obtained, and by applying the present invention, the electromagnetic properties can be significantly improved.

Table 2

[Brief explanation of the drawing]

Figure 1 shows the amount of solid solution (C+N) in the hot rolled sheet and the amount of (11
0) (001) relationship diagram with the random intensity ratio of the azimuth component,
Figure 2 is a relationship between rolling temperature and random intensity ratio of (110) (001) orientation component after annealing, Figure 3 is a relationship between rolling temperature and magnetic flux density, and Figure 4 is a relationship between rolling temperature and random intensity ratio of (110) (001) orientation components after annealing. It is a relationship diagram with an iron loss value. 7th surface A sphere z3, (C0A/) (1)/) M) 2 θ pressure χ temperature (te2 θ 4tt) d<li e rolling,
& Cliff (Den 4th page θ first #V ω 6θ0) King Shunzo Ukebono () 4 (°Bino

Claims (1)

[Claims] Steel with a solid solution (C0N) of 10 ppm or more is
Rolling is performed at a reduction rate of 20 inches or more in a temperature range of ~500℃, followed by recrystallization annealing to improve the texture (1
10) A method for producing an electrical steel sheet using warm rolling, which is characterized by developing a (001) orientation component.