KR960005227B1 - Method of magnetic domain microscopic - Google Patents

Abstract

The device includes winding reels(10), guide reels(20), tension parts(30), upper face rolling part(40) containing gear roll(41), work roll(42), first back-up roll(43) and second back-up roll (44), and lower face rolling parts(50) containing gear roll(51), work roll(52), 1st back-up roll (53) and 2nd back-up roll(54). The silicon steel slab comprises in weight percent, 2 to 4% silicon, 0.02 to 0.07% carbon, 0.02 to 0.04% soluble aluminum, 0.06 to 0.08% manganese, 0.02 to 0.03% sulfur, 60 to 90ppm nitrogen, and the balance of iron and inevitable impurities. The sheet is produced by the processes of general hot rolling of the silicon steel slab having the same chemical composition as mentioned above as a starting material, annealing of the hot rolled sheet, pickling, cold rolling, decarbonizing of the cold rolled sheet, and then deforming of the decarbonized sheet by domain miniaturizing process with indentation loading of 80 to 140kg/mm2.

Description

Iron loss improvement method and magnetic domain micronization apparatus of oriented electrical steel sheet by magnetic domain micronization

1 is a state of use of the magnetic domain refinement device of the present invention.

FIG. 2 (a) is a front view of the gear roll of the magnetic domain micronizing device according to the present invention, and FIG. 2 (b) is a side view of the gear roll of FIG. 2 (a).

3 is a front view of another gear roll of the micronized device in accordance with the present invention.

4 is a microstructure photograph of the indentation groove of the oriented electrical steel sheet indented and refined magnetic domain according to the present invention, Figure 4 (a) is a 50 times photograph of the surface portion, Figure 4 (b) is a rolling direction cross-section 100 Pear picture.

Figure 5 is a 10 times photograph of the magnetic domain of the grain-oriented electrical steel sheet indented in accordance with the present invention to refine the magnetic domain.

6 is a graph showing the iron loss improvement rate according to the pressure load.

* Explanation of symbols for main parts of the drawings

10: winding reel 20: guide reel

30: tension part 40: top press part

50: lower surface pressing portion 41, 51: gear roll

42, 52: work roll 43, 53: first back-up roll I

44, 54: second back-up roll II

The present invention relates to a method for improving the iron loss of a grain-oriented electrical steel sheet used as an iron core material of an electric machine, and more particularly, to a method for improving the iron loss of a grain-oriented electrical steel sheet by a magnetic domain micronizing treatment and a magnetic domain microprocessor It is about.

A grain-oriented electrical steel sheet is used as an iron core material for electrical equipment such as transformers. In order to reduce power loss and increase efficiency of electrical equipment, a steel sheet having low magnetic loss and high magnetic flux density is required. As a method of improving the magnetic properties of oriented electrical steel sheet, the Japanese patent has a method of reducing the growth of the primary recrystallized grains and reducing the deviation from the {100} <001> goss orientation of the secondary recrystallized grains. It is presented in Gazette No. 33-4790. The grain-oriented electrical steel sheet produced by this method has a high magnetic flux density due to the high degree of directivity of the secondary recrystallized grains, but has a large grain size and thus a 180 ° magnetic domain width.

In order to remedy the above disadvantages, the magnetic micronization technology has been developed. The magnetic micronization technology irradiates or scratches the surface of the steel sheet in the direction perpendicular to the rolling direction by laser, plasma jet, or mechanical methods. There are known methods for reducing iron loss by miniaturizing magnetic domains.

Among the above methods, a method of miniaturizing magnetic domains using a laser is disclosed in Japanese Patent Application Laid-Open No. 58-26405 and U.S. Patent No. 4203784, and the mechanical method is Japanese Patent Publication No. 58-5968 or the like. A method of miniaturizing magnetic domains using the same is disclosed in Japanese Patent Laid-Open No. 62-96617.

However, in the above methods for minimizing magnetic domains to reduce iron loss, the iron core transformer is eliminated by stress relief annealing and the iron loss reduction effect disappears. Transformers can be used, but the core core transformer (Wound Core Transformer) that requires stress relief annealing is not available.

The technique of micronization to solve this disadvantage is presented in Korean Patent Publication No. 90-7448, which is pressurized and annealed steel sheet to form fine recrystallized grains in the indentation part, so that the micronized effect by stress removal annealing Will not be destroyed.

However, the microrecrystallization grains generally have a weak microsphere refining effect, and have a point where the microsphere refining effect is not constant according to the orientation of the microrecrystallization grains.

The present inventors have conducted research and experiments to solve the above problems of the conventional methods, and based on the results of the present invention, the present invention provides a constant indentation of the rolling surface of the steel sheet using an appropriate magnetic micronization apparatus. Method to improve the iron loss of oriented electrical steel sheet by minimizing the magnetic domain by indentation by load to form a fine slip band perpendicular to the rolling direction so that the miniaturization of the magnetic domain is not affected by stress relief annealing An object of the present invention is to provide a refiner.

Hereinafter, the present invention will be described in detail by the drawings.

As shown in FIG. 1, the magnetic domain micronizing device of the present invention faces each other to give tension to the winding reel 10 and the steel sheet 1 which are positioned to face each other to wind or unwind the steel sheet 1. Located between the tensioning portion 30, the guide portion 20 for guiding the steel sheet 1 is located between the winding reel 10 and the tensioning portion 30, the tensioning portion 30 is located The upper surface press-in part 40 which makes a groove in the upper surface of the steel plate 1, and the lower surface press-in part 50 which makes a groove in the lower surface of the steel plate 1 are comprised.

The upper press-fitting part 40 positioned between the tension applying parts 30 to make a groove on the upper surface of the steel plate 1 and a lower press-fitting part 50 to make a groove on the lower surface of the steel plate 1 are configured. do. The tension imparting part 30 is formed of a conventional pinch roll, and the guide part 20 is formed of a conventional guide roll by allowing the steel sheet 1 to be wound or released in place. The upper press-fitting part 40 has a gear roll 41 positioned at an upper portion thereof, a work roll 42 positioned at an interval such that the steel sheet can be plated against the gear roll 41, and a uniform groove. The first backup roll 43 positioned below the work roll 42 to control the shape, and the second backup roll 44 positioned below the first backup roll 43 to serve as a supporting point of the load. It is configured to include.

On the surface of the gear roll 41, as shown in FIG. 2, a blade (Knife) having a blade arrangement angle α of 45-90 ° with respect to the gap 1 and the roll rotation direction 1-10 mm (l) ( 410 is formed, the end of the day is preferably formed to form an angle (β) of 30-150 °. When the distance ℓ of the blade 410 of the gear roll 41 is 10 mm or more, the effect of magnetization fineness is not sufficient, and when it is 1 mm or less, the amount of deformation introduced into the steel sheet is too large to increase iron loss. It is preferable to limit the spacing l of the blade to 1-10 mm.

When the blade arrangement angle α becomes 90 ° with respect to the roll rotation direction, it becomes parallel to the length direction of the roll, and the steel sheet 1 and the blade 410 contact at a right angle, making the steel sheet 1 difficult to travel and the contact area. If the indentation load required to increase slippage is large, it is not desirable. If the rotational direction is less than 45 °, the direction of the new magnetic domain around the indentation groove is out of the magnetization direction and the iron loss increases. It is preferable to limit to the range of 45-90 degrees with respect to the roll rotation direction.

In addition, when the angle β of the blade tip is 30 ° or less, the wear of the roll is severe and uneconomical, and when the angle of the blade tip is 150 ° or more, the width of the groove becomes too large, so the angle β of the blade tip is limited to 30-150 °. It is desirable to.

As shown in FIG. 2, the blades 410 may be formed to be inverted from each other in a symmetrical manner, and as shown in FIG. 3, the blades 410 may be inclined only in one direction.

When the blade is formed to be symmetrically inverted in the center of the roll as shown in FIGS. 1 and 2, the steel plate 1 prevents the one side from being pulled to one side when passing the gear roll 41 and the work roll 42. It is effective to

In the case of the lower face press-fitting part 50, it is configured in the same manner as the upper press-fitting part 40, except that the position of the gear roll is located at the bottom.

And, the means for operating the upper face press portion 40 and the lower face press portion 50 is the same as in a conventional rolling mill.

The method of micronized using the magnetic micronized device of the present invention configured as described above will be described.

Materials that can be applied to the present invention include silicon steel hot-rolled, pre-annealed, pickling, two times cold rolling, including one or intermediate annealing to produce a grain-oriented electrical steel sheet by applying a high temperature annealing and tension coating, decarbon annealing, MgO coating In the method, any one can be used as long as the hot-annealed steel sheet or the coated steel sheet.

Preferred materials that can be applied to the present invention include Si: 2-4% by weight, C: 0.02-0.07% by weight, acid solubility A1: 0.02-0.04% by weight, Mn: 0.06-0.08% by weight, S: 0.02-0.03% by weight Steel slabs composed of%, N: 60-90ppm, balance Fe and other unavoidable impurities are coated with two cold rolling, decarbon annealing, MgO, including hot rolling, hot rolling annealing, pickling, one time or intermediate annealing, and then hot Annealed hot annealed plates or tension coated plates after high temperature annealed.

After winding the hot-annealed steel sheet or tension-coated steel sheet manufactured as described above in one winding reel 10, and then unwinding the steel sheet 1 again, the guide portion 20, the tension applying portion 30, and the upper press-in portion 40. In this case, the magnetic refining process of the present invention is completed by winding the lower winding part 50, the tension applying part 30, and the guide part 20 in order to wind the other winding reel 10 in turn.

Top and bottom press-fitting of the steel sheets at the press-in portions 40 and 50 is performed by idling one of the gear rolls 41 and 51 and the work rolls 42 and 52, respectively. At this time, it is preferable to limit the indentation load to 80-140kg / mm2 when indenting the upper and lower surfaces of the steel sheet in the upper and lower press-in portions 40 and 50 to form grooves. This is because when it is less than 80 kg / mm 2, the effect of magnetic domain fineness is weak, and when it exceeds 140 kg / mm 2, fine recrystallized grains, which are harmful to magnetism, are generated, resulting in less magnetization.

As described above, when the upper and lower surfaces of the steel sheets are press-fitted into the upper and lower surfaces by the press-in portions 40 and 50, the steel sheets are raised at the minute portions where the gear rolls 41 and 51 and the steel sheet 1 contact. In the lower surface, a tensile force due to the frictional force is generated, and slip occurs in the steel sheet due to the indentation load applied and the force of the tensile force.

The directional electric field is made of a chaotic cubic lattice and the main slip system is {110} <111>. Among the slip systems, slip occurs in the slip system having the highest resolved shear stress. In the case of oriented electrical steel sheet in the (110) [001] Goss direction, slip occurs in the {110} <111> direction. On the rolled surface (steel plate surface), slip bands are formed at right angles to the rolling direction and at an angle of 57 ° to the cross section in the rolling direction. Around this slip band, the atomic arrangement differs from that of the goth-bearing steel plate, which results in a magnetic free pole, which changes the magnetostatic energy, thus miniaturizing magnetic domains and reducing iron losses.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

By weight, a silicon steel slab consisting of 3% Si, 0.065% C, 0.027% acid soluble A1, 0.065% Mn, 0.024% S, 80ppm N and the rest of Fe is 5 hours at 1400 ° C. After heating, hot rolling was carried out to a thickness of 2.3 mm, the hot rolled plate was annealed at 1120 ° C. for 2 minutes, pickled, and cold rolled to a thickness of 0.30 mm. The cold rolled plate was decarbonized for 3 minutes at 840 ° C., coated with MgO, and hot annealed at 1200 ° C. for 20 hours. The hot annealing plate was press-fitted under the indentation load as shown in Table 1 using the magnetic micronization apparatus of FIG. 1, tension coated, and then stress-annealed at 850 ° C. for 3 hours. It is shown in Table 1 below as compared to that of a conventional oriented electrical steel sheet subjected to tension coating and stress relief annealing.

However, in the magnetic domain micronizing apparatus of FIG. 1, the space | interval of the blade formed in the surface of the gear roll was 5 mm, the blade tip angle was 120 degrees, and the egg array angle was 65 degrees.

On the other hand, the invention material (2) in the specimen of Table 1 was observed in the microstructure photograph and magnetic domain around the indentation groove after the stress relief annealing and are shown in Figs. 4 and 5. 4 (a) shows a 50 times picture of the surface portion around the indentation groove, (b) shows a 100 times picture of the rolling direction surface part, and FIG. 5 shows a 10 times picture of the magnetic domain.

TABLE 1

Example 2

By weight%, a silicon steel slab consisting of 3% Si, 0.065% C, 0.027% acid solubility A1, 0.065% Mn, 0.024% S, 80 ppm N and the rest of Fe is 5 hours at 1400 ° C. After heating, hot rolling was carried out to a thickness of 2.3 mm, the hot rolled plate was annealed at 1120 ° C. for 2 minutes, pickled, and cold rolled to a thickness of 0.30 mm. The cold rolled plate was subjected to decarbonization annealing at 840 ° C. for 3 minutes, coated with MgO and subjected to tension coating after annealing at 1200 ° C. for 20 hours. The tension coating plate was press-fitted with the indentation load as shown in Table 2 using the magnetic micronization apparatus of FIG. 1, and then stress-annealed at 850 ° C. for 3 hours, and the magnetic properties were measured. The measurement results were subjected to high temperature annealing, tension coating and stress relief annealing. It is shown in Table 2 below compared with that of a conventional oriented electrical steel sheet.

However, in the refiner of FIG. 1, the interval between the blades formed on the surface of the gear roll was 5 mm, the blade tip angle was 120 °, and the light array angle was 65 °.

TABLE 2

Example 3

By weight, a silicon steel slab consisting of 3% Si, 0.065% C, 0.027% acid soluble A1, 0.065% Mn, 0.024% S, 80ppm N and the rest of Fe is 5 hours at 1400 ° C. After heating, hot rolling was performed to a thickness of 2.3 mm, and then the hot rolled plate was pickled and first cold rolled to a thickness of 1.5 mm. After the primary cold rolled sheet was annealed at 1120 ° C. for 2 minutes, cold rolled with a 0.23 mm thick cold rolled plate, decarbonized at 840 ° C. for 3 minutes, coated with MgO, and hot annealed at 1200 ° C. for 20 hours. After tension coating. The tension coating plate was press-fitted with the indentation load of the following Table 3 using the magnetic micronization apparatus of FIG. 1, and then stress-annealed at 850 ° C. for 3 hours, and then the magnetic properties were measured. The measurement results were subjected to high temperature annealing, tension coating and stress relief annealing. The roughening is shown in Table 3 below compared to that of a conventional oriented electrical steel sheet.

However, in the magnetic domain micronizing apparatus of FIG. 1, the space | interval of the blade formed in the surface of the gear roll was 5 mm, the blade tip angle was 120 degrees, and the blade arrangement angle was 65 degrees.

TABLE 3

As can be seen in Examples 1-3, when the hot annealing plate or the tension coating plate is press-fitted by applying the 80-140kg / mm indentation load using the magnetic micronizing device of the present invention [Invention material (1-12)] After the stress relief annealing, it can be seen that the iron loss is significantly lowered by maintaining the micronized effect.

Example 4

A grain-oriented electrical steel sheet was manufactured under the same conditions as in Example 1 except that the indentation load was changed as in FIG. The iron loss improvement rate according to the indentation load was investigated for the grain-oriented electrical steel sheet, and the results are shown in FIG.

As shown in Figure 6, it can be seen that the iron loss improvement rate is excellent in the indentation load range corresponding to the scope of the present invention.

Example 5

By weight, a silicon steel slab consisting of 3% Si, 0.065% C, 0.027% acid soluble A1, 0.07% Mn, 0.025% S, 80 ppm N and the balance Fe is heated at 1400 ° C. for 5 hours. After the hot rolling was performed by hot rolling with a thickness of 2.3 mm, the hot rolled sheet was annealed at 1120 ° C. for 2 minutes, pickled, and cold rolled to a thickness of 0.30 mm. The cold rolled plate was decarbonized for 3 minutes at 840 ° C., coated with MgO, and hot annealed at 1200 ° C. for 20 hours. The magnetic properties of the high temperature annealing plate were (W17 / 50) of 1.10W / kg.

The hot-annealed steel sheet was press-fitted under tension of 100kg / mm 2 using the magnetic micronization apparatus of FIG. 1, tension-coated, and then stress-annealed at 850 ° C. for 2 hours, and then the magnetic properties were measured. It is shown in Table 4 below as compared to that of a conventional oriented electrical steel sheet subjected to coating and stress relief annealing.

However, in the magnetic domain micronizing apparatus of FIG. 1, the space | interval of the blade formed in the surface of a gear roll was 5 mm, and the blade tip angle and blade arrangement angle were changed as Table 4 below.

TABLE 4

As shown in Table 4, by using a gear roll formed with a blade (Knife) having a blade spacing, blade tip angle and blade arrangement angle according to the present invention by indenting to the indentation load according to the present invention to refine the magnetic domain, It can be seen that a grain-oriented electrical steel sheet having high magnetic flux density and low iron loss has excellent magnetic properties.

As described above, the present invention can be used in a coil core transformer, etc., in which stress removal annealing is essential, because the magnetic domain fineness effect is maintained even after the stress relief annealing by press-fitting the magnetic domain by pressing the upper and lower surfaces of the steel sheet using a magnetic micro-fine device. There is an effect that can provide a low iron loss oriented electrical steel sheet.

Claims (5)

An apparatus for miniaturizing magnetic domains in a grain-oriented electrical steel sheet in a mechanical manner, comprising: a winding reel 10 positioned to face each other to wind or unwind steel sheets; A tension imparting part 30 facing each other to impart tension to the steel sheet; A guide part 20 positioned between the winding reel 10 and the tension applying part 30 to guide the steel sheet; Directional electricity characterized in that it comprises an upper surface press-in portion 40, which is located between the tension imparting portion 30 to groove the upper surface of the steel sheet and the lower surface press-in portion 50 to groove the lower surface of the steel sheet Grain refiner of steel plate. The method of claim 1, wherein the guide portion 20 is made of a conventional guide roll; The tension imparting portion 30 is made of a conventional pinch roll: and the upper and lower press-fit portions 40 and 50 are gear rolls 41, 51, work rolls 42, 52 and the first, respectively. Magnetic backing device of the grain-oriented electrical steel sheet comprising a backup roll (43, 53), and the second backup roll (44, 54). The surface of the gear roll 41 is a blade (Knife) having a spacing of 1-10 mm, blade array angle of 45-90 ° and tip angle of 30-150 ° with respect to the rotational direction of the roll The magnetic domain micronizing device of the grain-oriented electrical steel sheet which is formed. The device of claim 3, wherein the blades are symmetrically inclined with respect to the center in the longitudinal direction of the roll. By weight% 2-4% Si, 0.02-0.07% C, 0.02-0.04% acid soluble A1, 0.06-0.08% Mn, 0.02-0.03% S, 60-90 ppm N and other impurities The conventional silicon steel is hot rolled, hot rolled sheet annealed, pickling, cold rolled, and decarbonized, and then subjected to mechanical deformation to a hot-annealed hot-annealed steel sheet or a tension-coated tension-coated steel sheet after hot-annealed. In the method for improving the iron loss of the grain-oriented electrical steel sheet by miniaturizing the magnetic domain, the gear roll 41, the work roll 42, the first backup roll 43 and the second backup roll 44 are arranged in order from the top The upper surface indentation portion 40, and the lower surface indentation portion 50 configured to be arranged in order from the second backup rate 54, the first backup rate 53, the work roll 52, and the gear roll 51. The gear roll 41 and the work roll 42 by pressing the high-temperature annealed steel sheet or tension coated steel sheet under a press-fitting load of 80-140 kg / mm 2 using The iron loss improvement method of the grain-oriented electrical steel sheet by the magnetization fineness, characterized in that the plate between the work roll 52 and the gear roll 51 to press the upper and lower surfaces of the steel sheet to scratch the upper and lower surfaces to make the magnetic domain fine .