NON-ORIENTED ELECTRICAL STEEL SHEET

Abstract

A non-oriented electrical steel sheet of the present invention has a chemical composition capable of causing - transformation, in which, in a case where an area ratio of grains having a crystal orientation of an {hkl}<uvw>orientation (within a tolerance of 10) when measured by EBSD is denoted as Ahkl-uvw, A411011 is 15.0% or more, and the non-oriented electrical steel sheet has an average grain size of 10.0 m to 40.0 m.

Claims

1. A non-oriented electrical steel sheet comprising, as a chemical composition, by mass %: C: 0.0100% or less; Si: 1.5% to 4.0%; sol. Al: 0.0001% to 1.000%; S: 0.0100% or less; N: 0.0100% or less; one or more selected from the group consisting of Mn, Ni, and Cu: 2.5% to 5.0% in total; Co: 0.0% to 1.0%; Sn: 0.00% to 0.40%; Sb: 0.00% to 0.40%; P: 0.000% to 0.400%; one or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: 0.000% to 0.010% in total, in which Expression (1) is satisfied in a case where a Mn content (mass %) is indicated as [Mn], a Ni content (mass %) is indicated as [Ni], a Cu content (mass %) is indicated as [Cu], a Si content (mass %) is indicated as [Si], a sol. Al content (mass %) is indicated as [sol. Al], and a P content (mass %) is indicated as [P]; and a remainder consisting of Fe and impurities, wherein, in a case where an area ratio of grains having a crystal orientation of an {hkl}<uvw>orientation (within a tolerance of 10) when measured by EBSD is denoted as Ahkl-uvw, A411011 is 15.0% or more, and the non-oriented electrical steel sheet has an average grain size of 10.0 m to 40.0 m,
(2[Mn]+2.5[Ni]+[Cu])([Si]+2[sol.Al]+4[P])1.50%(1)

2. The non-oriented electrical steel sheet according to claim 1, wherein, in a case where a number average value of grain orientation spread (GOS) values when measured by EBSD is indicated as Gs, the non-oriented electrical steel sheet has a Gs of 0.5 to 0.8.

3. The non-oriented electrical steel sheet according to claim 1, wherein a magnetic flux density B50 in a 450 direction with respect to a rolling direction is 1.70 T or more, and an iron loss W10/400 in the 45 direction with respect to the rolling direction is 16.0 W/kg or less.

4. The non-oriented electrical steel sheet according to claim 2, wherein a magnetic flux density B50 in a 45 direction with respect to a rolling direction is 1.70 T or more, and an iron loss W10/400 in the 45 direction with respect to the rolling direction is 16.0 W/kg or less.

Description

EXAMPLES

[0181] Next, the non-oriented electrical steel sheet according to the embodiment of the present invention will be described in detail with reference to Examples.

[0182] Examples shown below are merely examples of the non-oriented electrical steel sheet according to the embodiment of the present invention, and the non-oriented electrical steel sheet according to the present invention is not limited to the following examples.

First Example

[0183] Molten steel was cast to produce an ingot having the composition shown in Table 1-1. Here, a left side of an expression represents a value of the left side of Expression (1). In addition, Mg and the like represent the total amount of one or more selected from the group consisting of Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd. Thereafter, the produced ingot was heated to 1,150 C., hot-rolled, and finish-rolled at the finish rolling temperature FT shown in Table 2. Cooling was then performed under the cooling conditions shown in Table 2 after the final pass (a time until the cooling is started after the final pass, and a temperature of a steel sheet after 3 seconds after the steel sheet had passed through the final pass).

[0184] Next, the hot-rolled sheet was not subjected to hot-rolled sheet annealing, scale was removed by pickling, and cold rolling was performed at the rolling reduction RR1 shown in Table 2. Then, process annealing was performed in an atmosphere of 20% hydrogen and 80% nitrogen. The process annealing was performed for 30 seconds while controlling a process annealing temperature T1 to the temperature shown in Table 2.

[0185] In addition, No. 24, hot-rolled sheet annealing for holding the hot-rolled sheet at 1,000 C. for 1 minute was performed.

[0186] Next, except for No. 11, skin pass rolling was performed at the rolling reduction RR2 shown in Table 2. Then, final annealing was performed at the final annealing temperature T2 shown in Table 2 in an atmosphere of 100% hydrogen. Here, a holding time t2 at the final annealing temperature T2 was set to the time shown in Table 2.

[0187] In addition, in order to examine a texture after the final annealing, a part of the non-oriented electrical steel sheet was cut off, and the cut test piece was reduced to a thickness. A {411}<011>ratio was obtained by observing a measurement region by EBSD under the above-described measurement conditions. In addition, regarding a number average value Gs of GOS values, an ODF was created under the above-described conditions using OMI Analysis 7.3 in the measurement region by EBSD, data of the created ODF was output, and a number average value of GOS values was obtained and used as Gs. The number average value Gs of the GOS values was also obtained before the final annealing. The results of each are shown in Table 3.

[0188] In addition, in order to examine magnetic properties and a tensile strength after the final annealing, a magnetic flux density B50 and an iron loss W10/400 were measured. In addition, as an index of stress sensitivity, an iron loss deterioration percentage of an iron loss W10/50 under a compressive stress was obtained.

[0189] Regarding the magnetic flux density B50, a 55 mm square sample was collected as a measurement sample in two directions, a 0 direction and a 450 direction with respect to a rolling direction. The magnetic flux density B50 was measured for these two types of samples by the above-described method. An average value of magnetic flux densities in the 45 direction and a 135 direction with respect to the rolling direction was defined as the magnetic flux density B50 in the 45 direction, and an average value in the 0 direction, the 45 direction, a 90 direction, and the 135 direction with respect to the rolling direction was defined as an all-directional average magnetic flux density B50. In a case where the magnetic flux density B50 in the 450 direction was 1.70 T or more, the non-oriented electrical steel sheet was determined to be a non-oriented electrical steel sheet having a high magnetic flux density and was thus determined to be acceptable. On the other hand, in a case where the magnetic flux density B50 in the 45 direction was less than 1.70 T, the non-oriented electrical steel sheet was not determined to be a non-oriented electrical steel sheet having a high magnetic flux density and was thus determined to be unacceptable. In addition, in a case where the magnetic flux density B50 in the 45 direction was 1.70 T or more and the all-directional average magnetic flux density B50 was 1.55 T or more, the non-oriented electrical steel sheet was determined to be a non-oriented electrical steel sheet having a higher magnetic flux density.

[0190] Regarding the iron loss W10/400, the iron loss W10/400 in the 45 direction was obtained by the above-described method using the above-mentioned sample collected in the 45 direction with respect to the rolling direction.

[0191] Furthermore, regarding the iron loss deterioration percentage W.sub.x[%] of the iron loss W10/50 under a compressive stress, in a case where an iron loss W10/50 with no stress was indicated as W10/50(0) and an iron loss W10/50 under a compressive stress of 10 MPa was indicated as W1050(10), the iron loss deterioration percentage W.sub.x was calculated by the following expression. The iron loss W10/50 was obtained by measuring an all-directional average energy loss (W/kg) that had occurred when an AC magnetic field of 40 Hz was applied to achieve a maximum magnetic flux density of 1.0 T using the sample collected in the 45 direction with respect to the rolling direction and a single sheet magnetic property measuring device.

[0192] In a case where the iron loss W10/400 in the 45 direction was 16.0 W/kg or less and the iron loss deterioration percentage W.sub.x was 40.0% or less, the non-oriented electrical steel sheet was determined to be a non-oriented electrical steel sheet having a low iron loss and was thus determined to be acceptable. On the other hand, in a case where the iron loss W10/400 in the 45 direction was more than 16.0 W/kg, or in a case where the iron loss deterioration percentage W.sub.x was more than 40.0%, the non-oriented electrical steel sheet was not determined to be a non-oriented electrical steel sheet having a low iron loss and was thus determined to be unacceptable.

[0193] The tensile strength was obtained by collecting a JIS No. 5 test piece whose longitudinal direction was the rolling direction of the steel sheet and conducting a tensile test according to JIS Z 2241:2011. In a case where the tensile strength was 600 MPa or more, the non-oriented electrical steel sheet was determined to be a non-oriented electrical steel sheet having a high strength and was thus determined to be acceptable. On the other hand, in a case where the tensile strength was less than 600 MPa, the non-oriented electrical steel sheet was not determined to be a non-oriented electrical steel sheet having a high strength and was thus determined to be unacceptable.

[0194] The measurement results are shown in Table 3.

W.sub.x={W10/50(10)W10/50(0)}/W10/50(0)

TABLE-US-00001 TABLE 1 Left Transformation Chemical composition (remainder including Fe and impurities) Mg and side of point C Si sol. Al S N Mn Ni Cu Co Sn Sb P the like formula Ar1 Ac1 Ac3 Item [mass [mass [mass [mass [mass [mass [mass [mass [mass [mass [mass [mass [mass [mass point point point No. % % % % % % % % % % % % % % [ C.] [ C.] [ C.] 1 0.0018 2.5 0.005 0.0018 0.0011 3.0 0.0 0.0 0.0 0.00 0.00 0.020 0.000 3.41 779 932 982 2 0.0018 2.5 0.005 0.0018 0.0011 3.0 0.0 0.0 0.0 0.00 0.00 0.020 0.000 3.41 779 932 982 3 0.0018 2.5 0.300 0.0018 0.0011 2.0 0.0 0.0 0.0 0.00 0.00 0.020 0.000 0.82 4 0.0012 2.4 0.120 0.0015 0.0014 2.8 0.2 0.0 0.0 0.03 0.01 0.010 0.004 3.42 777 929 979 5 0.0018 2.5 0.005 0.0018 0.0011 3.0 0.0 0.0 0.0 0.00 0.00 0.020 0.000 3.41 779 932 982 6 0.0009 2.5 0.070 0.0008 0.0008 3.5 0.0 0.2 0.2 0.00 0.11 0.080 0.000 4.24 657 780 850 7 0.0009 2.5 0.800 0.0008 0.0008 4.0 0.0 0.0 0.0 0.00 0.11 0.100 0.000 3.50 759 908 957 8 0.0012 2.6 0.500 0.0015 0.0014 2.6 0.0 0.2 0.0 0.15 0.00 0.010 0.000 1.71 953 1049 1088 9 0.0012 1.0 0.005 0.0015 0.0014 2.5 0.0 0.0 0.0 0.15 0.00 0.010 0.000 3.95 673 820 848 10 0.0012 3.5 0.800 0.0015 0.0014 5.2 0.0 0.0 0.0 0.15 0.00 0.010 0.000 5.26 633 760 812 11 0.0022 3.4 0.020 0.0042 0.0023 3.7 0.0 0.0 0.0 0.00 0.00 0.006 0.005 3.94 699 897 975 12 0.0022 3.4 0.020 0.0042 0.0023 3.7 0.0 0.0 0.0 0.00 0.00 0.006 0.005 3.94 699 897 975 13 0.0018 2.5 0.005 0.0018 0.0011 3.0 0.0 0.0 0.0 0.00 0.00 0.020 0.000 3.41 779 932 982 14 0.0054 1.8 0.200 0.0018 0.0011 3.0 0.0 0.0 0.0 0.00 0.00 0.020 0.000 3.72 732 901 966 15 0.0018 3.5 0.300 0.0012 0.0013 4.0 0.0 0.0 0.0 0.00 0.00 0.020 0.000 3.82 708 899 958 16 0.0018 2.5 0.250 0.0018 0.0011 0.0 2.8 0.0 0.0 0.00 0.00 0.020 0.000 3.92 675 881 934 17 0.0018 2.0 0.005 0.0018 0.0011 0.0 0.0 4.0 0.0 0.00 0.00 0.020 0.000 1.91 938 1038 1067 18 0.0018 2.5 0.005 0.0018 0.0011 3.0 0.0 0.0 0.0 0.00 0.00 0.020 0.000 3.41 779 932 982 19 0.0022 3.4 0.020 0.0042 0.0023 3.7 0.0 0.0 0.0 0.00 0.00 0.006 0.005 3.94 699 897 975 20 0.0009 2.5 0.800 0.0008 0.0008 4.0 0.0 0.0 0.0 0.00 0.11 0.100 0.000 3.50 759 908 957 21 0.0009 2.5 0.070 0.0008 0.0008 3.5 0.0 0.2 0.2 0.00 0.11 0.080 0.000 4.24 657 780 850 22 0.0018 2.5 0.005 0.0018 0.0011 3.0 0.0 0.0 0.0 0.00 0.00 0.020 0.000 3.41 779 932 982 23 0.0018 1.8 0.200 0.0018 0.0011 3.0 0.0 0.0 0.0 0.00 0.00 0.020 0.000 3.72 732 901 966 24 0.0018 2.5 0.005 0.0018 0.0011 3.0 0.0 0.0 0.0 0.00 0.00 0.020 0.000 3.41 779 932 982 Underlines indicate outside of the ranges of the present invention.

TABLE-US-00002 TABLE 2 Cold rolling step Process Skin pass Hot rolling step Rolling annealing step rolling step Final annealing step Finish reduction Process Rolling Final rolling Temperature RR1 annealing reduction RR2 annealing Final temperature Start of after 3 of cold temperature of skin pass temperature annealing Item FT cooling seconds rolling T1 rolling T2 time t2 No. [ C.] [sec] [ C.] [%] [ C.] [%] [ C.] [sec] Evaluation 1 950 0.10 700 86 700 15 800 30 Present Invention Example 2 950 0.10 200 86 700 15 800 120 Comparative Example 3 950 0.10 700 86 700 15 800 25 Comparative Example 4 950 0.50 400 86 700 15 820 40 Present Invention Example 5 650 0.10 550 86 700 15 800 55 Comparative Example 6 850 0.08 600 86 700 15 900 50 Comparative Example 7 850 0.12 600 86 700 15 800 25 Present Invention Example 8 1050 0.50 600 86 700 15 850 30 Present Invention mple 9 950 0.50 400 86 700 15 800 10 Comparative Example 10 850 0.12 400 86 700 15 800 30 Comparative Example 11 950 0.10 650 86 700 0 800 40 Comparative Example 12 950 0.10 650 86 700 25 800 40 Comparative Example 13 1050 0.10 500 86 700 15 800 30 Comparative Example 14 900 0.10 650 86 700 15 800 30 Present Invention Example 15 900 0.10 600 86 700 15 800 30 Present Invention Example 16 900 0.10 600 86 700 15 800 30 Present Invention Example 17 950 0.10 700 86 700 15 800 30 Present Invention Example 18 850 0.05 400 86 700 15 800 30 Comparative Example 19 950 0.10 250 86 700 15 800 30 Comparative Example 20 850 0.10 600 86 950 15 800 30 Comparative Example 21 800 0.10 600 86 500 15 800 30 Comparative Example 22 950 0.10 700 86 700 15 700 20 Comparative Example 23 900 0.10 650 86 700 15 850 80 Comparative Example 24* 950 0.10 700 86 700 15 800 30 Comparative Example Underlines indicate manufacturing conditions that are not preferable. *Hot-rolled sheet annealing for holding the hot-rolled sheet at 1,000 C. for 1 minute was performed.

TABLE-US-00003 TABLE 3 Texture Magnetic properties After After after final Micro- Iron loss Mechanical skin final annealing structure B50 deterioration properties pass annealing (411)<011> Sheet Average (all- B50 W10/400 percentage Tensile Item Gs Gs ratio thickness grain size directional) (45) (45) Wx strength No [] [] [%] [mm] [m] [T] [T] [W/kg] [%] [MPa] Evaluation 1 2.2 0.7 24.3 0.3 29.6 1.64 1.79 14.0 31.3 652 Present Invention Example 2 1.7 0.4 11.2 0.3 56.3 1.62 1.73 14.7 50.7 568 Comparative Example 3 2.1 0.8 8.3 0.3 24.2 1.65 1.60 16.3 54.5 679 Comparative Example 4 2.3 0.7 22.7 0.3 27.6 1.64 1.70 13.8 28.9 662 Present Invention Example 5 2.6 0.6 9.2 0.3 38.1 1.58 1.56 20.1 46.2 619 Comparative Example 6 1.8 0.7 12.5 0.3 27.4 1.57 1.69 26.4 50.7 662 Comparative Example 7 2.1 0.8 28.9 0.3 24.9 1.64 1.72 15.4 30.5 675 Present Invention Example 8 2.0 0.6 16.3 0.3 35.5 1.61 1.70 13.3 30.4 628 Present Invention Example 9 2.0 1.2 13.8 0.3 7.1 1.59 1.67 18.8 30.1 792 Comparative Example 10 2.3 0.7 25.6 0.3 31.5 1.51 1.58 15.2 31.9 644 Comparative Example 11 0.2 0.7 11.4 0.3 33.8 1.58 1.60 16.3 52.1 635 Comparative Example 12 3.1 0.6 12.1 0.3 36.2 1.57 1.63 16.4 33.5 626 Comparative Example 13 2.1 0.8 14.1 0.3 31.2 1.61 1.71 14.9 51.4 645 Comparative Example 14 2.0 0.7 21.7 0.3 22.0 1.63 1.72 15.3 32.8 621 Present Invention Example 15 2.2 0.6 23.1 0.3 28.8 1.60 1.70 13.1 31.1 674 Present Invention Example 16 2.0 0.7 22.4 0.3 30.6 1.62 1.76 13.9 30.8 648 Present Invention Example 17 2.2 0.7 21.9 0.3 28.7 1.61 1.75 14.1 31.0 656 Present Invention Example 18 1.8 0.6 14.2 0.3 31.9 1.62 1.72 13.8 53.7 643 Comparative Example 19 1.9 0.7 14.3 0.3 27.5 1.61 1.73 13.9 53.1 662 Comparative Example 20 2.6 0.8 11.1 0.3 26.4 1.55 1.58 22.5 51.8 667 Comparative Example 21 2.9 0.7 14.4 0.3 34.6 1.56 1.64 16.8 50.5 632 Comparative Example 22 2.2 1.1 14.0 0.3 11.7 1.52 1.61 17.7 51.2 774 Comparative Example 23 2.0 0.5 35.4 0.3 45.8 1.65 1.80 13.1 28.7 575 Comparative Example 24* 2.8 0.6 7.4 0.3 33.4 1.52 1.46 17.6 47.1 636 Comparative Example Underlines indicate outside of the ranges of the present invention, and manufacturing conditions that are not preferable. *Hot-rolled sheet annealing for holding the hot-rolled sheet at 1,000 C. for 1 minute was performed.

[0195] Underlines in Tables 1, 2, and 3 indicate conditions that deviated from the ranges of the present invention, manufacturing conditions that were not preferable, and property values that were not preferable. Present Invention Example Nos. 1, 4, 7, 8, and 14 to 17, which are present invention examples, had good values for all of the magnetic flux density B50, the iron loss W10/400, the iron loss deterioration percentage, and the tensile strength.

[0196] On the other hand, in Comparative Example No. 2, since the rapid cooling was performed after the finish rolling, the {411}<011>ratio became small and the iron loss deterioration percentage under a compressive stress was large. In addition, since the annealing time in the final annealing was too long, the average grain size became too large, and the tensile strength was insufficient.

[0197] In Comparative Example No. 3, since the total amount of one or more selected from the group consisting of Mn, Ni, and Cu was insufficient and a composition that did not cause - transformation was provided, the {411)}<011>ratio was small, and the magnetic flux density B50 (45 direction), the iron loss W10/400, and the iron loss deterioration percentage were inferior. Since No. 3 had the composition that did not cause - transformation, the Ar1, Ac1, and Ac3 points were not described.

[0198] In Comparative Example No. 5, since the finish rolling temperature FT was lower than the Ar1 point, the {411}<011>ratio was small, and the magnetic flux density B50 (45 direction), the iron loss W10/400, and the iron loss deterioration percentage were inferior.

[0199] In Comparative Example No. 6, since the time after the final pass of the finish rolling until the cooling was started was too short and the final annealing temperature was too high, the {411}<011>ratio was small, and the magnetic flux density B50 (45 direction), the iron loss W10/400, and the iron loss deterioration percentage were inferior.

[0200] In Comparative Example No. 9, since Si was insufficient and the annealing time in the final annealing was too short, the {411}<011>ratio was small, and the average grain size was too small. As a result, the magnetic flux density B50 (45 direction) and the iron loss W10/400 were inferior.

[0201] In Comparative Example No. 10, since the total amount of one or more selected from the group consisting of Mn, Ni, and Cu was excessive, the magnetic flux density B50 was inferior in both the 45 direction and the all-directional average. In addition, partial double cracking had occurred due to segregation during the cold rolling.

[0202] In Comparative Example No. 11, since the skin pass rolling was not performed, the {411}<011>ratio was small, and the magnetic flux density B50 (45 direction), the iron loss W10/400, and the iron loss deterioration percentage were inferior.

[0203] In Comparative Example No. 12, since the rolling reduction RR2 in the skin pass rolling was too large, the {411}<011>ratio was small, and the magnetic flux density B50 (45 direction) and the iron loss W10/400 were inferior.

[0204] In addition, Comparative Example Nos. 13, and 18 to 24 deviated from preferable manufacturing conditions and could not obtain a desired metallographic structure and desired properties.

INDUSTRIAL APPLICABILITY

[0205] According to the above aspect according to the present invention, it is possible to provide a non-oriented electrical steel sheet having a low iron loss, a high magnetic flux density, and a high strength.