Grain-oriented silicon steel having heat-resistant magnetic domain and manufacturing method thereof

Abstract

A heat-resistant magnetic domain refined grain-oriented silicon steel, a single-sided surface or a double-sided surface of which has several parallel grooves which are formed in a grooving manner, each groove extends in the width direction of the heat-resistant magnetic domain refined grain-oriented silicon steel, and the several parallel grooves are uniformly distributed along the rolling direction of the heat-resistant magnetic domain refined grain-oriented silicon steel. Each groove which extends in the width direction of the heat-resistant magnetic domain refined grain-oriented silicon steel is formed by splicing several sub-grooves which extend in the width direction of the heat-resistant magnetic domain refined grain-oriented silicon steel. The manufacturing method for a heat-resistant magnetic domain refined grain-oriented silicon steel comprises the step of: forming grooves on a single-sided surface or a double-sided surface of a heat-resistant magnetic domain refined grain-oriented silicon steel in a laser grooving manner, a laser beam of the laser grooving is divided into several sub-beams by a beam splitter, and the several sub-beams form the several sub-grooves which are spliced into the same groove.

Claims

1. A grain-oriented silicon steel having heat-resistant relined magnetic domain, the grain-oriented silicon steel comprising: multiple parallel grooves formed by grooving on surface of one side or of both sides of the grain-oriented silicon steel, wherein each groove extends in a width direction of the grain-oriented silicon steel, and said multiple parallel grooves are uniformly distributed along a rolling direction of the grain-oriented silicon steel having the heat-resistant refined magnetic domain, wherein said each groove that extends in the width direction of the grain-oriented silicon steel is formed by splicing multiple sub-grooves that extend in the width direction of the grain-oriented silicon steel having heat-resistant refined magnetic domain, wherein a cross-section of said each sub-groove in the width direction of the grain-oriented silicon steel is in shape of inverted trapezoid, a long side of the trapezoid has a length L.sub.t, and a hypotenuse of the trapezoid has a projected length l.sub.e in the width direction of the grain-oriented silicon steel, and wherein the projected length l.sub.e is in a range of no more than 8 mm.

2. The grain-oriented silicon steel having heat-resistant refined magnetic domain according to claim 1, wherein the trapezoid has a height m of 5 μm-60 μm.

3. The grain-oriented silicon steel having heat-resistant refined magnetic domain according to claim 1, wherein, among said multiple sub-grooves that forms into one groove, two adjacent sub-grooves are spliced in way of being closely connected with each other, or overlapping with each other, or being transversely spaced with each other.

4. The grain-oriented silicon steel having heat-resistant refined magnetic domain according to claim 3, wherein the two adjacent sub-grooves have a transverse space l.sub.b of no more than 10 mm when transversely spaced with each other.

5. The grain-oriented silicon steel having heat-resistant refined magnetic domain according to claim 4, wherein following formula is satisfied $\frac{l_e+l_b}{L_t}\le 0.2$ wherein, L.sub.t is the length of the long side of the trapezoid, l.sub.e is the projected length of the hypotenuse of the trapezoid in the width direction of the grain-oriented silicon steel having heat-resistant refined magnetic domain, and l.sub.b is a lateral spacing.

6. The grain-oriented silicon steel having heat-resistant refined magnetic domain according to claim 3, wherein the two adjacent sub-grooves have an overlapping length l.sub.e of an overlapped section of no more than 1.5 times of l.sub.e when the two adjacent sub-grooves overlap each other.

7. The grain-oriented silicon steel having heat-resistant refined magnetic domain according to claim 1, wherein adjacent grooves have a spacing d of 2-10 mm therebetween.

8. The grain-oriented silicon steel having heat-resistant refined magnetic domain according to claim 1, wherein adjacent grooves have a spacing d of 2 mm-10 mm, and the sub-grooves spliced into one groove have offset spacings d.sub.0 of no more than 0.4d in the rolling direction of the grain-oriented silicon steel.

9. The grain-oriented silicon steel having heat-resistant refined magnetic domain according to claim 1, wherein a grooving method of making the grooves is at least one selected from laser grooving, electrochemical grooving, teeth roller grooving, and high-pressure water jet grooving.

10. A method for manufacturing the grain-oriented silicon steel having heat-resistant refined magnetic domain according to claim 1, comprising steps of: forming grooves on surface of one side or both sides of the grain-oriented silicon steel by means of laser grooving, wherein the laser beam of the laser grooving is split into multiple sub-beams by a beam splitter for forming multiple sub-grooves that are spliced into one groove; thereby producing the grain-oriented silicon steel of claim 1.

11. The method according to claim 10, wherein a laser generating pump used for laser grooving is at least one selected from CO.sub.2 lasers, solid-state lasers, and fiber lasers.

12. The method according to claim 10, wherein a sub-spot formed by a single said sub-beam on the surface of the grain-oriented silicon steel has a single pulse instantaneous peak power density of 5.0×10.sup.5 W/mm.sup.2-5.0×10.sup.11 W/mm.sup.2.

13. The method according to claim 12, wherein a ratio of the single pulse instantaneous maximum peak power density to the single pulse instantaneous minimum peak power density of the sub-spot is no more than 20.

14. The method according to claim 12, wherein a ratio of the diameter of the sub-spot to the interval between the focal centers of the sub-spots is in the range of 0.1-0.8.

15. The method according to claim 10, wherein the multiple sub-spots formed by the multiple sub-beams on the surface of the grain-oriented silicon steel have a total length of not more than 20 mm in the laser scanning direction.

16. The method according to claim 10, wherein the laser grooving is performed before or after the step of decarburization annealing of the grain-oriented silicon steel having heat-resistant refined magnetic domain; or, before or after the step of hot stretching leveling annealing of the grain-oriented silicon steel having heat-resistant refined magnetic domain.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic view showing a structure of the grooves of the grain-oriented silicon steel having heat-resistant refined magnetic domain in some embodiments according to the present invention;

(2) FIG. 2 is a schematic view showing a structure of any sub-groove of the grain-oriented silicon steel having heat-resistant refined magnetic domain in certain embodiments according to the present invention;

(3) FIG. 3 is a schematic view showing laser spectroscopy in the method for manufacturing the grain-oriented silicon steel having heat-resistant refined magnetic domain according to the present invention;

(4) FIG. 4 is a schematic view showing laser grooving at a viewing angle in the method for manufacturing the grain-oriented silicon steel having heat-resistant refined magnetic domain according to the present invention;

(5) FIG. 5 is a schematic view showing laser grooving at another viewing angle in the method for manufacturing the grain-oriented silicon steel having heat-resistant refined magnetic domain according to the present invention;

(6) FIG. 6 illustrates the shape and arrangement of the sub-spots formed by the sub-beams in certain embodiments of the method for manufacturing the grain-oriented silicon steel having heat-resistant refined magnetic domain according to the present invention;

(7) FIG. 7 illustrates the shape and arrangement of the sub-spots formed by the sub-beams in other embodiments of the method for manufacturing the grain-oriented silicon steel having heat-resistant refined magnetic domain according to the present invention;

(8) FIG. 8 illustrates the shape and arrangement of the sub-spots formed by the sub-beams in further embodiments of the method for manufacturing the grain-oriented silicon steel having heat-resistant refined magnetic domain according to the present invention;

(9) FIG. 9 illustrates the shape and arrangement of the sub-spots formed by the sub-beams in some embodiments of the method for manufacturing the grain-oriented silicon steel having heat-resistant refined magnetic domain according to the present invention;

(10) FIG. 10 illustrates the shape and arrangement of the sub-spots formed by the sub-beams in some other embodiments of the manufacturing method of the grain-oriented silicon steel having heat-resistant refined magnetic domain according to the present invention;

(11) FIG. 11 illustrates the shape and arrangement of the sub-spots formed by the sub-beams in still other embodiments in the manufacturing method of the grain-oriented silicon steel having heat-resistant refined magnetic domain according to the present invention.

DETAILED DESCRIPTION

(12) The following will further explain and describe the grain-oriented silicon steel having heat-resistant refined magnetic domain and the method according to the present invention in conjunction with the description of the drawings and specific embodiments. However, the explanation and description do not improperly limit the technical solutions of the present invention.

(13) It can be seen from FIG. 1 that each groove 1 of the grain-oriented silicon steel having heat-resistant refined magnetic domain in this technical solution extends in the width direction A, and said multiple parallel grooves 1 are uniformly distributed along the rolling direction B. The width direction A is perpendicular to the rolling direction B of the grain-oriented silicon steel having heat-resistant refined magnetic domain of Example 1. Each groove 1 is formed by splicing multiple sub-grooves 2 that extend in the width direction A. Two adjacent sub-grooves 2 overlap each other or have a transverse space l.sub.b between each other, and the overlapping length of the overlapped section formed by overlapping each other is l.sub.e. Two adjacent grooves 1 have a spacing d, and the sub-grooves 2 have offset spacings do in the rolling direction B.

(14) With further reference to FIG. 2, it can be seen that the cross-section of any sub-groove 2 of the grain-oriented silicon steel having heat-resistant refined magnetic domain of Example 1 in the width direction A is in shape of inverted trapezoid, the long side of the trapezoid has a length L.sub.t, the hypotenuse of the trapezoid has a projected length l.sub.e in the width direction A, and the trapezoid has a height m.

(15) It can be seen from FIG. 3, FIG. 4 and FIG. 5, combined with FIG. 1 and FIG. 2 when necessary, that in the method for manufacturing the grain-oriented silicon steel having heat-resistant refined magnetic domain of Example 1, the laser beam 3 of the laser grooving is split into multiple sub-beams 5 by a beam splitter 4, and the multiple sub-beams 5 are scanned along the width direction A of the grain-oriented silicon steel having heat-resistant refined magnetic domain of Example 1 for forming multiple sub-grooves 2 that are spliced into one groove 1. 6, 7, 8, 9, 10 are different types of lasers, and in this embodiment, they can be CO.sub.2 lasers, solid-state lasers, fiber lasers, and so on.

(16) FIG. 6, FIG. 7, FIG. 8, FIG. 9, FIG. 10, and FIG. 11 respectively show shapes and arrangements of the sub-spots formed by the sub-beams in various embodiments of the method for manufacturing the grain-oriented silicon steel having heat-resistant refined magnetic domain. As can be seen, they are a single row of circular spots, a single row of elliptical spots, two rows of circular spots, two rows of elliptical spots, and two rows of elliptical spots respectively. It should be noted that shapes and arrangements of these spots are only examples and schematic, and are not intended to limit this technical solution.

(17) Below, this technical solution will use specific example data to further describe the technical solution of this invention and prove its beneficial effects:

Examples 1-22 and Comparative Examples 1-10

(18) Table 1 lists the characteristic parameters of the grooves of grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 1-22 and Comparative Examples 1-10.

(19) TABLE-US-00001 TABLE 1 m (μm) L.sub.t (mm) l.sub.b (mm) l.sub.e (mm) σ l.sub.c (mm) d (mm) d.sub.0 (mm) d.sub.0/d Example 1  5 80  5 3 0.10  0.0  5.0 0.8 0.16 Example 2 10 60  5 3 0.13  0.0  5.0 0.9 0.18 Example 3 20 50  5 3 0.16  0.0  5.0 0.2 0.04 Example 4 30 50  5 3 0.16  0.0  5.0 1.0 0.20 Example 5 40 90  5 3 0.09  0.0  5.0 0.4 0.08 Example 6 50 60  5 3 0.13  0.0  5.0 0.0 0.00 Example 7 60 60  5 3 0.13  0.0  5.0 0.1 0.02 Example 8 20 80  6 3 0.11  0.0  5.0 0.5 0.10 Example 9 20 80  8 3 0.14  0.0  5.0 0.8 0.16 Example 10 20 80 10 3 0.16  0.0  5.0 0.1 0.02 Example 11 20 80  5 6 0.14  0.0  5.0 1.0 0.20 Example 12 20 80  5 7 0.15  0.0  5.0 0.9 0.18 Example 13 20 80  5 8 0.16  0.0  5.0 0.9 0.18 Example 14 20 40  5 3 0.20  0.0  5.0 0.6 0.12 Example 15 20 60  4 3 0.12  4.5  5.0 0.4 0.08 Example 16 20 60  4 5 0.15  7.5  5.0 0.6 0.12 Example 17 20 60  5 6 0.18  1.0  3.0 0.4 0.13 Example 18 20 60  5 6 0.18  1.0  6.0 0.2 0.03 Example 19 20 60  5 6 0.18  1.0 10.0 0.6 0.06 Example 20 20 60  5 6 0.18  1.0  2.0 0.5 0.25 Example 21  5 90 10 8 0.20 12.0 10.0 0.8 0.08 Example 22 60 90  5 6 0.12  1.5  2.0 0.3 0.15 Comparative 60  5 3 0.13  0.0  5.0 0.8 0.16 Example 1 Comparative 60  5 3 0.13  0.0  5.0 0.5 0.10 Example 2 Comparative 60  5 3 0.13  0.0  5.0 0.5 0.10 Example 3 80 3 0.18  0.0  5.0 0.6 0.12 Comparative 20 Example 4 80  5 0.18  0.0  5.0 0.6 0.12 Comparative 20 Example 5 53  5 6  0.0  5.0 0.6 0.12 Comparative 20 Example 6 60  4 3 0.12  5.0 0.4 0.08 Comparative 20 Example 7 60  4 5 0.15  5.0 0.4 0.08 Comparative 20 Example 8 60  5 6 0.18  1.0 0.4 0.27 Comparative 20 Example 9 60  5 6 0.18  1.0   0 0.00 Comparative 20 Example 10 $\mathrm{Amoung}\mathrm{them},\sigma =\frac{l_e+l_b}{L_t}.$

(20) The grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 1-22 and Comparative Examples 1-10 are obtained by the following steps of:

(21) (1) performing ironmaking, steelmaking, continuous casting, and hot rolling with the grain-oriented silicon steel, and then cold rolling to a final thickness of 0.23 mm;

(22) (2) performing a decarburization annealing of 850° C., then coating a separation agent MgO on the surface after forming an oxide layer, and rolling into steel coils;

(23) (3) annealing at a high temperature of 1200° C. for 20 hours, then coating a separation agent on the surface, and performing final annealing to form the grain-oriented silicon steel;

(24) (4) implementing laser grooving on the surface of one side of the grain-oriented silicon steel (the specific process parameters of laser grooving are listed in Table 2).

(25) Table 2 lists the specific process parameters of step (4) in the method for manufacturing the grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 1-22 and Comparative Examples 1-10.

(26) TABLE-US-00002 TABLE 2 Ratio of single pulse instantaneous maximum peak power Total density to Ratio of the length of Single pulse single pulse diameter of multiple instantaneous instantaneous sub-spot to sub-spots Laser peak power minimum the interval in laser output density of peak power between the scanning power sub-pot density of focal centers direction (W) (W/mm.sup.2) sub-spot of sub-spots (mm) Example 100 2.1E+07 2 0.31 4 1~22 Compar- 100 2.1E+07 2 0.31 4 ative Example 1~10

(27) The grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 1-22 and Comparative Examples 1-10 were tested for magnetic conductive performance (B.sub.8) and iron loss (P.sub.17/50) before and after laser grooving, specifically using Epstein method to test the magnetic flux density of the grain-oriented silicon steel under an exciting magnetic field of 800 A/m, and the values B.sub.8 in T were obtained; Epstein method was used to test the ineffective electric energy consumed by the magnetization of the grain-oriented silicon steel when the magnetic flux density reaches 1.7 T under an AC excitation field of 50 Hz, and the values P.sub.17/50 in W/Kg were obtained. Test results are listed in Table 3.

(28) TABLE-US-00003 TABLE 3 Before After Magnetic grooving grooving variation P.sub.17/50 B.sub.8 P.sub.17/50 B.sub.8 P.sub.17/50 B.sub.8 (W/kg) (T) (W/kg) (T) (%) (T) Example 1 0.864 1.926 0.801 1.923 7.3% 0.003 Example 2 0.889 1.922 0.803 1.921 9.7% 0.001 Example 3 0.876 1.920 0.788 1.916 10.0% 0.004 Example 4 0.869 1.930 0.761 1.922 12.4% 0.008 Example 5 0.852 1.934 0.742 1.928 12.9% 0.006 Example 6 0.860 1.923 0.736 1.911 14.4% 0.012 Example 7 0.860 1.929 0.731 1.912 15.0% 0.017 Example 8 0.844 1.932 0.767 1.928 9.1% 0.004 Example 9 0.912 1.916 0.800 1.914 12.3% 0.002 Example 10 0.882 1.929 0.818 1.928 7.3% 0.001 Example 11 0.825 1.937 0.731 1.931 11.4% 0.006 Example 12 0.831 1.932 0.765 1.931 8.0% 0.001 Example 13 0.843 1.922 0.788 1.921 6.5% 0.001 Example 14 0.855 1.919 0.798 1.918 6.6% 0.001 Example 15 0.855 1.921 0.796 1.920 6.9% 0.001 Example 16 0.867 1.920 0.812 1.920 6.3% 0.000 Example 17 0.840 1.926 0.723 1.918 14.0% 0.008 Example 18 0.868 1.921 0.761 1.919 12.3% 0.002 Example 19 0.858 1.919 0.798 1.918 7.0% 0.001 Example 20 0.868 1.917 0.735 1.908 15.3% 0.009 Example 21 0.846 1.938 0.793 1.920 6.3% 0.018 Example 22 0.845 1.930 0.721 1.912 14.7% 0.018 Comparative 0.875 1.916 0.825 1.915 5.7% 0.001 Example 1 Comparative 0.861 1.926 0.735 1.905 14.6% 0.021 Example 2 Comparative 0.889 1.919 0.761 1.889 14.4% 0.030 Example 3 Comparative 0.879 1.921 0.833 1.920 5.2% 0.001 Example 4 Comparative 0.878 1.920 0.828 1.920 5.7% 0.000 Example 5 Comparative 0.846 1.928 0.801 1.927 5.3% 0.001 Example 6 Comparative 0.837 1.931 0.801 1.930 4.3% 0.001 Example 7 Comparative 0.857 1.926 0.807 1.926 5.9% 0.000 Example 8 Comparative 0.830 1.934 0.721 1.913 13.1% 0.021 Example 9 Comparative 0.866 1.922 0.820 1.921 5.3% 0.001 Example 10

(29) It can be seen from Table 3 that Examples 1-22 have good properties of iron loss and magnetic conduction, and the improvement rates of iron loss after laser grooving are all above 6% compared with those before laser grooving.

(30) The trapezoid of Comparative Example 1 has a height m that is not within the scope of the present invention, and its improvement rate of iron loss is less than 6%.

(31) Although Comparative Examples 2 and 3 have higher improvement rate of iron loss of grooving, their heights m of the trapezoid are too large and are beyond the scope of the present invention, resulting in a significant decrease in the magnetic flux density B.sub.8.

(32) The transverse space l.sub.b between two adjacent sub-grooves of Comparative Example 4 and the projected length l.sub.e of the hypotenuse of the trapezoid of Comparative Example 5 in the width direction of the grain-oriented silicon steel having heat-resistant refined magnetic domain are not within the scope of the present invention. Therefore, the improvement rates of iron loss of grooving are poor.

(33) In Comparative Example 6, the length L.sub.t of the long side of the trapezoid, the transverse space l.sub.b between two adjacent sub-grooves, and the projected length l.sub.e of the hypotenuse of the trapezoid in the width direction of the grain-oriented silicon steel having heat-resistant refined magnetic domain are not within the range of the formula of the invention, so the grain-oriented silicon steel plate with significantly improved iron loss cannot be obtained.

(34) In Comparative Examples 7 and 8, since the overlapping lengths l.sub.c of the overlapped section overlapped by two adjacent sub-grooves are beyond the scope of the present invention, the grain-oriented silicon steel plate with significantly improved iron loss cannot be obtained.

(35) In Comparative Example 9, the spacing d between the adjacent grooves is too small, which exceeds the lower limit of the scope of the present invention, so that although the iron loss improves obviously, the magnetic flux density B.sub.8 is significantly reduced; while in Comparative Example 10, the spacing d between the adjacent grooves exceeds the upper limit of the scope of the present invention, so that the improvement rate of iron loss is low, and the grain-oriented silicon steel plate with good magnetic properties cannot be obtained.

Examples 23-37 and Comparative Examples 11-15

(36) Table 4 lists the characteristic parameters of the grooves of the grain-oriented silicon steel having heat-resistant refined magnetic domain of Examples 23-37 and Comparative Examples 11-15.

(37) TABLE-US-00004 TABLE 4 m (μm) L.sub.t (mm) l.sub.b (mm) l.sub.e (mm) σ l.sub.c (mm) d (mm) d.sub.0 (mm) d.sub.0/d Example 23 28 80 4 3 0.09 0.2 2 0.2 0.10 Example 24 25 80 4 3 0.09 0.2 2 0.4 0.20 Example 25 24 80 4 3 0.09 0.1 2 0.8 0.40 Example 26 27 80 4 3 0.09 0.1 4 0.5 0.13 Example 27 24 80 4 3 0.09 0.2 4 1 0.25 Example 28 27 80 4 3 0.09 0.2 4 1.6 0.40 Example 29 26 80 4 3 0.09 0.0 6 1 0.17 Example 30 27 80 4 3 0.09 0.1 6 2 0.33 Example 31 24 80 4 3 0.09 0.1 6 2.4 0.40 Example 32 24 80 4 3 0.09 0.1 8 1 0.13 Example 33 25 80 4 3 0.09 0.2 8 2 0.25 Example 34 25 80 4 3 0.09 0.1 8 3.2 0.40 Example 35 28 80 4 3 0.09 0.0 10 1 0.10 Example 36 25 80 4 3 0.09 0.1 10 2 0.20 Example 37 27 80 4 3 0.09 0.2 10 4 0.40 Comparative 24 80 4 3 0.09 0.1 2   Example 11 Comparative 26 80 4 3 0.09 0.0 4   Example 12 Comparative 24 80 4 3 0.09 0.2 6   Example 13 Comparative 25 80 4 3 0.09 0.2 8   Example 14 Comparative 28 80 4 3 0.09 0.2 10   Example 15 $\mathrm{Amoung}\mathrm{them},\sigma =\frac{l_e+l_b}{L_t}.$

(38) The grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 23-37 and Comparative Examples 11-15 are obtained by the following steps of:

(39) (1) performing ironmaking, steelmaking, and hot rolling with the grain-oriented silicon steel, and then cold rolling to a thickness of 0.26 mm;

(40) (2) implementing laser grooving on the surface of both sides of the cold-rolled plate (the specific process parameters of laser grooving are listed in Table 5);

(41) (3) performing a decarburization annealing of 850° C. with the cold-rolled plate after grooving, then coating a separation agent MgO on its surface after forming an oxide layer, and rolling into steel coils;

(42) (4) annealing at a high temperature of 1200° C. for 20 hours, then coating a separation agent on the surface and performing final annealing to form the silicon steel plate.

(43) Table 5 lists the specific process parameters of step (2) in the method for manufacturing the grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 23-27 and Comparative Examples 11-15.

(44) TABLE-US-00005 TABLE 5 Ratio of single pulse instantaneous maximum peak power Total density to Ratio of the length of Single pulse single pulse diameter of multiple instantaneous instantaneous sub-spot to sub-spots Laser peak power minimum the interval in laser output density of peak power between the scanning power sub-pot density of focal centers direction (W) (W/mm.sup.2) the sub-spot of sub-spots (mm) Example 500 2.2E+06 3 0.30 10 23-37 Compar- 500 2.2E+06 3 0.30 10 ative Example 11-15

(45) The grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 23-27 and Comparative Examples 11-15 were tested for magnetic conductive performance (B.sub.8) and iron loss (P.sub.17/50), specifically using Epstein method to test the magnetic flux density of the grain-oriented silicon steel under an exciting magnetic field of 800 A/m, and the values B.sub.8 in T were obtained; Epstein method was used to test the ineffective electric energy consumed by the magnetization of the grain-oriented silicon steel when the magnetic flux density reaches 1.7 T under an AC excitation field of 50 Hz, and the values P.sub.17/50 in W/Kg were obtained. The values AWV.sub.17/50 of AC magnetostrictive noise of the grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 23-37 and Comparative Examples 11-15 were tested using SST100×500 single sheet method, and the unit is dBA. The test results are listed in Table 6.

(46) TABLE-US-00006 TABLE 6 P.sub.17/50 B.sub.8 AWV.sub.17/50 (W/kg) (T) (dBA) Example 23 0.817 1.914 57.5 Example 24 0.822 1.910 57.0 Example 25 0.820 1.911 58.0 Example 26 0.840 1.919 57.0 Example 27 0.837 1.921 58.4 Example 28 0.820 1.917 58.8 Example 29 0.832 1.918 57.9 Example 30 0.837 1.922 57.1 Example 31 0.841 1.917 58.6 Example 32 0.849 1.922 57.5 Example 33 0.821 1.928 57.2 Example 34 0.853 1.917 58.0 Example 35 0.852 1.919 57.5 Example 36 0.865 1.919 58.2 Example 37 0.843 1.927 58.4 Comparative 0.810 1.917 60.2 Example 11 Comparative 0.823 1.926 59.5 Example 12 Comparative 0.842 1.921 59.2 Example 13 Comparative 0.830 1.931 59.8 Example 14 Comparative 0.852 1.921 60.6 Example 15

(47) It can be seen from Table 6 that the iron loss P.sub.17/50 and values of the magnetic flux density B.sub.8 of Examples 23-37 and Comparative Examples 11-15 are both good, while the values of d.sub.0/d of Comparative Examples 11-15 are not within the scope of the present invention, making the AC magnetostrictive noise obviously loud.

Examples 38-54 and Comparative Examples 16-21

(48) Table 7 lists the characteristic parameters of the grooves of the grain-oriented silicon steel having heat-resistant refined magnetic domain of Examples 38-54 and Comparative Examples 16-21.

(49) TABLE-US-00007 TABLE 7 m (μm) L.sub.t (mm) l.sub.b (mm) l.sub.e (mm) σ l.sub.c (mm) d (mm) d.sub.0 (mm) d.sub.0/d Example 38 28.7 60 2 2.6 0.08 1 5.0 0.4 0.08 Example 39 28.4 60 2 2.6 0.08 1 5.0 0.2 0.04 Example 40 28.2 60 2 2.1 0.07 1 5.0 0.0 0.00 Example 41 28.7 60 2 1.6 0.06 1 5.0 0.2 0.04 Example 42 28.2 60 2 1.2 0.05 1 5.0 0.4 0.08 Example 43 12.0 60 2 2.1 0.07 1 5.0 0.0 0.00 Example 44 18.0 60 2 0.6 0.04 1 5.0 0.4 0.08 Example 45 27.0 60 2 1.3 0.06 1 5.0 0.1 0.02 Example 46 28.4 60 2 7.1 0.15 1 5.0 0.3 0.06 Example 47 28.3 60 2 4.3 0.11 1 5.0 0.4 0.08 Example 48 28.6 60 2 6.8 0.15 1 5.0 0.3 0.06 Example 49 28.1 60 2 8.0 0.17 1 5.0 0.1 0.02 Example 50 28.0 60 2 4.3 0.11 1 5.0 0.3 0.06 Example 51 28.1 60 2 4.3 0.11 1 5.0 0.4 0.08 Example 52 28.6 60 2 4.3 0.11 1 5.0 0.2 0.04 Example 53 28.3 60 2 4.3 0.11 1 5.0 0.4 0.08 Example 54 15.0 60 2 8.0 0.17 1 5.0 0.4 0.08 Comparative 10.0 60 2 2.1 0.07 1 5.0 0.1 0.02 Example 16 Comparative 28.1 60 2 2.1 0.07 1 5.0 0.3 0.06 Example 17 Comparative 9.7 60 2 7.1 0.15 1 5.0 0.0 0.00 Example 18 Comparative 9.8 60 2 1.1 0.05 1 5.0 0.3 0.06 Example 19 Comparative 18.0 60 2 7.8 0.16 1 5.0 0.4 0.08 Example 20 Comparative 8.8 60 2   0.18 1 5.0 0.2 0.04 Example 21 $\mathrm{Amoung}\mathrm{them},\sigma =\frac{l_e+l_b}{L_t}.$

(50) The grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 38-54 and Comparative Examples 16-21 are obtained by the following steps of:

(51) (1) performing ironmaking, steelmaking, and hot rolling with the grain-oriented silicon steel, and then cold rolling to a thickness of 0.226 mm;

(52) (2) performing a decarburization annealing, and coating a separation agent MgO on the surface of the steel plate and kiln drying, then rolling into steel coils;

(53) (3) annealing at a high temperature of 1200° C. for 20 hours, and washing off the unreacted residual MgO on the surface to obtain the cold-rolled plate;

(54) (4) implementing laser grooving on the surface of one side of the cold-rolled plate, and the specific process parameters are listed in Table 8;

(55) (5) coating a separation agent on the surface and performing final annealing to form the silicon steel plate.

(56) Table 8 lists the specific process parameters of step (4) in the method for manufacturing the grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 38-54 and Comparative Examples 16-21.

(57) TABLE-US-00008 TABLE 8 Ratio of single pulse instantaneous maximum peak power Total density to Ratio of the length of Single pulse single pulse diameter of multiple instantaneous instantaneous sub-spot to sub-spots peak power minimum the interval in laser density of peak power between the scanning sub-pot density of focal centers direction (W/mm.sup.2) the sub-spot of sub-spots (mm) Example 38 1.3E+10 8 0.33 6 Example 39 1.3E+09 5 0.33 6 Example 40 1.7E+08 5 0.32 5 Example 41 2.2E+07 2 0.30 4 Example 42 3.3E+06 2 0.26 3 Example 43 5.0E+05 1 0.32 5 Example 44 5.0E+11 1 0.19 2 Example 45 4.1E+07 2 0.79 6 Example 46 1.2E+08 2 0.11 15 Example 47 1.2E+08 2 0.16 10 Example 48 8.3E+07 2 0.16 15 Example 49 6.2E+07 2 0.16 20 Example 50 1.2E+08 1 0.16 10 Example 51 1.2E+08 5 0.16 10 Example 52 1.2E+08 10 0.16 10 Example 53 1.2E+08 15 0.16 10 Example 54 1.2E+08 20 0.16 10 Comparative 1 0.32 5 Example 16 Comparative 1 0.19 2 Example 17 Comparative 1.2E+08 0.16 10 Example 18 Comparative 4.8E+07 2 5 Example 19 Comparative 1.2E+08 2 18 Example 20 Comparative 2.1E+07 2 0.30 Example 21

(58) The grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 38-54 and Comparative Examples 16-21 were tested for magnetic conductive performance (B.sub.8) and iron loss (P.sub.17/50), specifically using Epstein method to test the magnetic flux density of the grain-oriented silicon steel under an exciting magnetic field of 800 A/m, and the values B.sub.8 in T were obtained; Epstein method was used to test the ineffective electric energy consumed by the magnetization of the grain-oriented silicon steel when the magnetic flux density reaches 1.7 T under an AC excitation field of 50 Hz, and the values P.sub.17/50 in W/Kg were obtained. “Method for measuring density, resistivity and stacking factor of an electrical steel sheet (strip) in GB/T19289-2003” was used to test lamination factors of the grain-oriented silicon steels having heat-resistant refined magnetic domain of Examples 38-54 and Comparative Examples 16-21. The test results are listed in Table 9.

(59) TABLE-US-00009 TABLE 9 P.sub.17/50 B.sub.8 Lamination (W/kg) (T) factor Example 38 0.783 1.910 96.1% Example 39 0.779 1.914 96.4% Example 40 0.788 1.912 96.9% Example 41 0.791 1.907 96.5% Example 42 0.796 1.911 96.6% Example 43 0.799 1.919 96.8% Example 44 0.788 1.907 95.8% Example 45 0.799 1.920 97.2% Example 46 0.789 1.911 95.2% Example 47 0.779 1.909 96.1% Example 48 0.788 1.914 96.2% Example 49 0.796 1.921 97.1% Example 50 0.789 1.916 96.9% Example 51 0.791 1.911 96.6% Example 52 0.789 1.915 96.2% Example 53 0.791 1.911 95.9% Example 54 0.798 1.918 95.5% Comparative 0.843 1.924 97.2% Example 16 Comparative 0.798 1.911 94.5% Example 17 Comparative 0.832 1.911 94.0% Example 18 Comparative 0.821 1.922 97.3% Example 19 Comparative 0.802 1.909 94.2% Example 20 Comparative 0.837 1.920 97.1% Example 21

(60) It can be seen from Table 9 that values of P.sub.17/50 and B.sub.8 of Examples 38˜54 in this case are all good.

(61) In Comparative Examples 16 and 17, the single pulse instantaneous peak power densities of the sub-pots are not within the scope of the present invention. P.sub.17/50 of the silicon steel plate of Comparative Example 16 is obviously poor, and the lamination factor of Comparative Example 17 is significantly reduced;

(62) in Comparative Example 18, the ratio of the maximum value to the minimum value of the single pulse instantaneous peak power density of the sub-spot is not within the scope of the present invention, resulting in poor magnetic performance and poor lamination factor;
in Comparative Examples 19 and 20, the ratio of the diameter of the sub-spot to the interval between the focal centers of the sub-spots is not within the scope of the present invention. P.sub.17/50 of Comparative Example 19 is poor, and P.sub.17/50 and the lamination factor of Comparative Example 20 are poor;
in Comparative Example 21, the total length of the multiple sub-spots in the laser scanning direction is not within the scope of the present invention, making the value P.sub.17/50 poor.

(63) It should be noted that the prior art part of the protection scope of the present invention is not limited to the embodiments given in this application document, and all prior arts that do not contradict the solution of the present invention, including but not limiting the previous patent documents, prior publications, prior public use, etc., can all be included in the protection scope of the present invention.

(64) In addition, the combination of various technical features in this case is not limited to the combination described in the claims of this case or the combination described in the specific embodiments. All technical features described in this case can be freely combined or integrated in any way, unless conflicts arise among them.

(65) It should also be noted that the embodiments listed above are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and the subsequent similar changes or modifications that can be directly derived from or easily associated with the disclosure of the present invention by those skilled in the art, should fall within the protection scope of the present invention.