NON-ORIENTED ELECTRICAL STEEL SHEET AND MANUFACTURING METHOD THEREFOR

Abstract

A non-oriented electrical steel sheet according to an embodiment of the present invention includes, in wt %, Si: 2.1 to 3.8%, Mn: 0.001 to 0.6%, Al: 0.001 to 0.6%, Bi: 0.0005 to 0.003%, and Ge: 0.0003 to 0.001%, and the balance of Fe and inevitable impurities.

Claims

1. A non-oriented electrical steel sheet including, in wt %, Si: 2.1 to 3.8%, Mn: 0.001 to 0.6%, Al: 0.001 to 0.6%, Bi: 0.0005 to 0.003%, and Ge: 0.0003 to 0.001%, and the balance of Fe and inevitable impurities.

2. The non-oriented electrical steel sheet of claim 1, further comprising one or more of P: 0.08 wt % or less, Sn: 0.08 wt % or less, and Sb: 0.08 wt % or less.

3. The non-oriented electrical steel sheet of claim 1, further comprising one or more of C: 0.01 wt % or less, S: 0.01 wt % or less, N: 0.01 wt % or less, and Ti: 0.005 wt % or less.

4. The non-oriented electrical steel sheet of claim 1, wherein one or more of Cu, Ni, and Cr are further included in an amount of 0.05 wt % or less, respectively.

5. The non-oriented electrical steel sheet of claim 1, wherein one or more of Zr, Mo, and V are further included in an amount of 0.01 wt % or less, respectively.

6. The non-oriented electrical steel sheet of claim 1, wherein when an EBSD test is performed on a 1/6 to 1/4 region of a thickness of the steel sheet, a strength of a {111} plane facing a <112>direction based on a rolling direction on an ODF is 2 or less compared to a random orientation.

7. The non-oriented electrical steel sheet of claim 1, wherein in a region of 1/6 to 1/4 of a thickness of the steel sheet, a ratio (V{100}/V{411}) of a fraction (V{100}) of texture in which a {100} plane of the texture and a rolling plane are parallel within a 15° angle with respect to a fraction (V{411}) of the texture in which a {411} plane of the texture and the rolling plane are parallel within a 15° angle, is 0.150 to 0.450.

8. The non-oriented electrical steel sheet of claim 1, wherein in a region of 1/6 to 1/4 of a thickness of the steel sheet, a ratio (V{100}/V{411}) of a fraction (V{100}) of texture in which a {100} plane of the texture and a rolling plane are parallel within a 10° angle with respect to a fraction (V{411}) of the texture in which a {411} plane of the texture and the rolling plane are parallel within a 10° angle, is 0.350 to 0.550.

9. The non-oriented electrical steel sheet of claim 1, wherein in a region of 1/6 to 1/4 of a thickness of the steel sheet, a ratio (V{100}/V{411}) of a fraction (V{100}) of texture in which a {100} plane of the texture and a rolling plane are parallel within a 5° angle with respect to a fraction (V{411}) of the texture in which a {411} plane of the texture and the rolling plane are parallel within a 5° angle, is 0.450 to 0.650.

10. A manufacturing method of a non-oriented electrical steel sheet, comprising: hot-rolling a slab that includes, in wt %, Si: 2.1 to 3.8%, Mn: 0.001 to 0.6%, Al: 0.001 to 0.6%, Bi: 0.0005 to 0.003%, and Ge: 0.0003 to 0.001%, the balance of Fe, and inevitable impurities to manufacture a hot-rolled sheet; cold-rolling the hot-rolled sheet to manufacture a cold-rolled sheet; and final annealing the cold-rolled sheet.

11. The manufacturing method of the non-oriented electrical steel sheet of claim 10, further comprising after the manufacturing of the hot-rolled sheet, annealing the hot-rolled sheet at a temperature of 900 to 1195° C. for 30 to 95 seconds.

12. The manufacturing method of the non-oriented electrical steel sheet of claim 10, wherein the final annealing is performed at a temperature of 850 to 1080° C. for 60 to 150 seconds.

Description

[0076] Hereinafter, the present invention will be described in more detail through examples. However, the examples are only for illustrating the present invention, and the present invention is not limited thereto.

EXAMPLE

[0077] Slabs including the alloy compositions and the balance of Fe and inevitable impurities summarized in Table 1 and Table 2 below were manufactured. The slab was heated at 1150° C., hot-rolled, and then wound. The wound and cooled hot-rolled steel sheet was annealed and pickled at the temperatures shown in Table 2 below, then cold-rolled to the thicknesses shown in Table 2, and finally cold-rolled sheet annealed. In this case, the annealing temperatures are summarized in Table 2.

[0078] The manufactured final annealed sheet was formed as an Epstein specimen with a length of 305 mm and a width of 30 mm for magnetic measurement from an L direction (rolling direction) and a C direction (rolling vertical direction), and the iron loss (W.sub.15/50) and magnetic flux density (B.sub.50) were measured, and the results are shown in Table 3 below.

[0079] In addition, in order to measure the texture, a 5 mm×5 mm area thereof was observed by using EBSD. The texture characteristics were obtained based on the observed data, and the results are shown in Table 3 below.

[0080] The Iron loss (W.sub.15/50) is average loss (W/kg) of the rolling direction and the transverse direction when the magnetic flux density of 1.5 Tesla is induced at a frequency of 50 Hz.

[0081] The magnetic flux density (B.sub.50) is a magnetic flux density (Tesla) induced when a magnetic field of 5000 A/m is applied.

TABLE-US-00001 TABLE 1 Example Si Mn Al P C S N Ti Sn Sb Comparative 3.69 0.33 0.56 0.005 0.0015 0.0007 0.0015 0.0007 0.05 0.01 Material 1 Comparative 3.45 0.02 0.25 0.001 0.0013 0.0015 0.0021 0.0012 0.04 0.01 Material 2 Comparative 3.02 0.47 0.07 0.007 0.0007 0.0030 0.0024 0.0009 0.04 0.01 Material 3 Comparative 2.86 0.05 0.12 0.010 0.0021 0.0021 0.0008 0.0013 0.01 0.03 Material 4 Inventive 3.12 0.01 0.01 0.004 0.0025 0.0018 0.0013 0.0015 0.05 0.01 Material 1 Inventive 2.95 0.03 0.21 0.001 0.0005 0.0010 0.0014 0.0010 0.02 0.02 Material 2 Inventive 2.69 0.15 0.13 0.001 0.0014 0.0009 0.0027 0.0008 0.04 0.03 Material 3 Inventive 2.61 0.27 0.05 0.002 0.0027 0.0014 0.0019 0.0008 0.04 0.01 Material 4 Inventive 3.05 0.22 0.30 0.008 0.0008 0.0017 0.0017 0.0004 0.06 0.06 Material 5 Inventive 2.71 0.22 0.27 0.003 0.0013 0.0008 0.0005 0.0020 0.04 0.01 Material 6 Inventive 2.15 0.05 0.07 0.010 0.0011 0.0025 0.0009 0.0016 0.07 0.02 Material 7 Inventive 3.06 0.41 0.50 0.009 0.0020 0.0012 0.0026 0.0016 0.03 0.07 Material 8 Inventive 2.51 0.56 0.24 0.007 0.0016 0.0004 0.0007 0.0014 0.02 0.08 Material 9 Inventive 3.03 0.08 0.01 0.007 0.0022 0.0013 0.0026 0.0005 0.01 0.04 Material 10 Inventive 3.10 0.46 0.57 0.005 0.0004 0.0016 0.0006 0.0006 0.08 0.02 Material 11

TABLE-US-00002 TABLE 2 Hot-rolled Hot-rolled plate plate Final annealing annealing annealing Final Thickness temperature time temperature annealing Example Bi Ge (μm) (° C.) (s) (° C.) time (s) Comparative 0.0001 0.0003 0.27 900 80 1040 120 Material 1 Comparative 0.0015 0.0001 0.3 930 80 1000 100 Material 2 Comparative 0.0044 0.0008 0.3 950 80 980 80 Material 3 Comparative 0.0025 0.0014 0.35 970 50 1020 120 Material 4 Inventive 0.0005 0.0007 0.27 930 80 1040 100 Material 1 Inventive 0.0013 0.0008 0.27 930 60 1000 120 Material 2 Inventive 0.0010 0.0008 0.27 950 60 980 120 Material 3 Inventive 0.0021 0.0010 0.3 920 80 960 50 Material 4 Inventive 0.0026 0.0005 0.3 920 80 1020 120 Material 5 Inventive 0.0008 0.0006 0.3 950 70 1040 120 Material 6 Inventive 0.0016 0.0006 0.3 970 60 1040 70 Material 7 Inventive 0.0016 0.0005 0.35 990 40 980 70 Material 8 Inventive 0.0012 0.0009 0.35 980 40 990 100 Material 9 Inventive 0.0025 0.0008 0.35 950 60 950 100 Material 10 Inventive 0.0023 0.0010 0.35 950 60 950 80 Material 11

TABLE-US-00003 TABLE 3 V{001}/ Iron Magnetic V{411} V{001}/V{411} V{001}/V{411} loss flux at 15 degrees at 10 degrees at 5 degrees (W15/ density I{111} < V{001}/ V{001}/ V{001}/ 50, (B50, Example 112> V{411} V{411} V{411} W/kg) T) Comparative 2.2 0.06 0.253 0.382 2.05 1.64 Material 1 Comparative 1.5 0.101 0.318 0.451 2.3 1.65 Material 2 Comparative 1.8 0.172 0.412 0.446 2.28 1.65 Material 3 Comparative 1.5 0.01 0.129 0.217 2.61 1.65 Material 4 Inventive 1.6 0.152 0.386 0.554 2.41 1.71 Material 1 Inventive 1.4 0.193 0.501 0.612 2.27 1.71 Material 2 Inventive 1.5 0.178 0.36 0.535 2.39 1.73 Material 3 Inventive 1.8 0.294 0.519 0.645 2.23 1.72 Material 4 Inventive 0.9 0.268 0.413 0.602 1.95 1.7 Material 5 Inventive 1.1 0.345 0.479 0.514 1.92 1.7 Material 6 Inventive 1.3 0.32 0.445 0.646 2.31 1.74 Material 7 Inventive 1.4 0.279 0.439 0.534 2.18 1.69 Material 8 Inventive 1.4 0.162 0.363 0.607 2.33 1.72 Material 9 Inventive 0.8 0.207 0.422 0.511 2.36 1.71 Material 10 Inventive 1.2 0.23 0.411 0.559 2.15 1.68 Material 11

[0082] As shown in Table 1 to Table 3, Inventive Material 1 to Inventive Material 11, in which Si, Al, Mn, Bi, and Ge satisfied respective component addition ranges, had the improved texture, and showed the excellent iron loss W.sub.15/50 and magnetic flux density B50.

[0083] On the other hand, it can be confirmed that Comparative Example 1 included too little Bi, so the texture was not improved and the magnetism was inferior.

[0084] It can be confirmed that Comparative Example 2 included too little Ge, so the texture was not improved and the magnetism was inferior.

[0085] It can be confirmed that Comparative Example 3 included an excess of Bi, so the texture was not improved and the magnetism was inferior.

[0086] It can be confirmed that Comparative Example 4 included an excess of Ge, so the texture was not improved and the magnetism was inferior.

[0087] The present invention may be embodied in many different forms, and should not be construed as being limited to the disclosed embodiments. In addition, it will be understood by those skilled in the art that various changes in form and details may be made thereto without departing from the technical spirit and essential features of the present invention. Therefore, it is to be understood that the above-described embodiments are for illustrative purposes only, and the scope of the present invention is not limited thereto.