Double-oriented silicon steel and preparation method thereof

Abstract

The invention belongs to the technical field of silicon steel preparation, relates to double-oriented silicon steel and a preparation method thereof, solves the problems of rolling cracking and strengthening of a metastable cubic texture through reasonable component design and strict control of a manufacturing process, and breaks through the bottleneck of the manufacturing technology of the double-oriented silicon steel. According to the prepared double-oriented silicon steel, the rolling magnetic induction intensity B8 is larger than or equal to 1.60 T, the transverse magnetic induction intensity B8 is larger than or equal to 1.55 T, the iron loss P10 / 400 is smaller than or equal to 11.00 W / kg, the iron loss P2 / 1000 is smaller than or equal to 2.00 W / kg, and the saturation magnetostriction lambda s is smaller than or equal to 0.9 * 10 <-6 >. According to the prepared double-oriented silicon steel, the texture regulation and control problems that traditional high-Si steel cracks during warm rolling and a metastable cubic texture is not easy to strengthen are solved, the double-oriented silicon steel with the thickness of 0.15-0.5 mm and the width of 150-500 mm can be prepared, the double-oriented silicon steel has bidirectional high magnetic induction in the rolling direction and the transverse direction, the high-frequency iron loss is low, the saturation magnetostriction is close to zero, and the preparation method is suitable for large-scale production. And the method has relatively high engineering application value and benefit.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon steel preparation, and specifically to a double-oriented silicon steel and a preparation method thereof. Background Art

[0002] The double-oriented 6.5wt% Si steel uses a strong cube texture ({001}<100>) as the magnetization carrier, and the rolling direction and transverse direction of the steel plate are respectively parallel to the <100> crystal direction that is easy to magnetize. Compared with the traditional non-oriented 3wt% Si steel and oriented 3wt% Si steel, using the double-oriented 6.5wt% Si steel to manufacture the iron cores of motors and transformers has three advantages: First, the cube texture of the double-oriented 6.5wt% Si steel has the advantage of bidirectional easy magnetization, which helps to increase the torque of the motor, improve the working efficiency of the transformer, and save the amount of iron core used. Second, a higher Si content helps to increase the resistance, reduce the high-frequency iron loss, and reduce the working energy consumption of the transformer and the motor. Third, the 6.5wt% Si content makes the saturation magnetostriction approach zero, reducing the working noise of the transformer and the motor. However, the manufacture of the double-oriented 6.5wt% Si steel faces two technical bottlenecks: First, the double-oriented 6.5wt% Si steel is limited by the high Si content, has high rolling brittleness, and when using conventional continuous casting and rolling, edge cracking or even fracture often occurs during warm rolling. Second, under the plane deformation conditions of conventional continuous casting and rolling, as the reduction increases, the cube texture gradually deflects to stable orientations such as {112}~{111}<11 ̅0>, and the strengthening of the cube texture is restricted by the competitive development of other textures, making it difficult to control the strong cube texture. Summary of the Invention

[0003] To solve the problems existing in the prior art, the main object of the present invention is to propose a double-oriented silicon steel and a preparation method thereof.

[0004] According to one aspect of the present invention, the following technical solution is provided: A preparation method of a double-oriented silicon steel, comprising the following steps: S1. Smelt to obtain the molten steel of the double-oriented silicon steel, the content of Si in the molten steel is 6.3 - 6.7wt%, and the content of Ce is 0.001 - 0.005%; and obtain a cast strip through thin strip continuous casting; S2. Hot roll the cast strip to obtain a hot rolled strip; S3. Normalize the hot rolled strip to obtain a normalized steel strip; S4. Warm roll the normalized steel strip to obtain a warm rolled steel strip; S5. High temperature anneal the warm rolled steel strip to obtain a high temperature annealed steel strip; S6. Cross roll the high temperature annealed steel strip to obtain a cross rolled steel strip; S7. Perform partial recrystallization annealing on the cross-rolled steel strip to obtain a partially recrystallized annealed steel strip; S8. Perform nitriding and isothermal homogenization treatment on the partially recrystallized annealed steel strip to obtain a nitrided and isothermally homogenized steel strip; S9. Perform high-temperature annealing on the nitrided and isothermally homogenized steel strip to obtain the double-oriented silicon steel.

[0005] According to another aspect of the present invention, the present invention provides the following technical solution: A double-oriented silicon steel is prepared by using the preparation method of the double-oriented silicon steel described above.

[0006] As a preferred embodiment of the double-oriented silicon steel described in the present invention, by mass percentage, it includes: Si: 6.3 - 6.7 wt%, Ce: 0.001 - 0.005 wt%, Al: 0.01 - 0.03 wt%, N: 0.005 - 0.009 wt%, S < 0.005 wt%, P < 0.008 wt%, and the balance is Fe and inevitable impurity elements.

[0007] As a preferred embodiment of the double-oriented silicon steel described in the present invention, the thickness of the double-oriented silicon steel is 0.15 - 0.5 mm, and the width is 150 - 500 mm.

[0008] As a preferred embodiment of the double-oriented silicon steel described in the present invention, the rolling direction magnetic induction intensity B 8 ≥1.60 T, the transverse magnetic induction intensity B 8 ≥1.55 T, the iron loss P 10 / 400 ≤11.00 W / kg, the iron loss P 2 / 1000 ≤2.00 W / kg, the saturation magnetostriction λs ≤ 0.9×10 -6 .

[0009] The beneficial effects of the present invention are as follows: The present invention provides a double-oriented silicon steel and its preparation method. By reasonable composition design and strict control of the manufacturing process, the problems of rolling cracking and strengthening of the metastable cubic texture are solved, and the manufacturing technical bottleneck of the double-oriented silicon steel is broken through. The rolling direction magnetic induction intensity B of the prepared double-oriented silicon steel 8 ≥1.60 T, the transverse magnetic induction intensity B 8 ≥1.55 T, the iron loss P 10 / 400 ≤11.00 W / kg, the iron loss P 2 / 1000 ≤2.00 W / kg, the saturation magnetostriction λs ≤ 0.9×10 -6。The double-oriented silicon steel prepared by the present invention overcomes the problems of texture control in traditional high-Si steel, such as cracking during warm rolling and difficulty in strengthening the metastable cube texture. It is possible to prepare double-oriented silicon steel with a thickness of 0.15 - 0.5 mm and a width of 150 - 500 mm, which has high magnetic induction in both the rolling direction and the transverse direction, low high-frequency iron loss, and a saturation magnetostriction close to zero, and has high engineering application value and benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0011] Figure 1 It is a photograph of the double-oriented silicon steel prepared in Example 1 of the present invention.

[0012] The realization of the object, functional features, and advantages of the present invention will be further described in conjunction with the embodiments with reference to the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] The following will clearly and completely describe the technical solutions in the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0014] The present invention provides a double-oriented silicon steel and its preparation method. The Si content is increased in traditional 3wt% Si steel, and a certain amount of Ce element is added, which has the effect of refining the solidification structure of the strip casting in thin strip continuous casting and improving the plasticity of the strip casting during warm rolling. A certain amount of Al and N elements are added, which have the effect of precipitating AlN inhibitors during normalizing treatment. The hot rolling, normalizing, warm rolling, high-temperature annealing, cross rolling, partial recrystallization annealing, nitriding, isothermal homogenization, and high-temperature annealing processes are designed in a matching manner to strengthen the metastable cube texture.

[0015] A preparation method of double-oriented silicon steel includes the following steps: S1. Smelt the molten steel of double-oriented silicon steel, where the Si content in the molten steel is 6.3 - 6.7wt% and the Ce content is 0.001 - 0.005%; and obtain a strip casting through thin strip continuous casting; S2. Hot roll the strip casting to obtain a hot rolled strip; S3. Perform normalizing treatment on the hot rolled strip to obtain a normalized steel strip; S4. Warm roll the normalized steel strip to obtain a warm-rolled steel strip; S5. Anneal the warm-rolled steel strip at a high temperature to obtain a high-temperature annealed steel strip; S6. Cross-roll the high-temperature annealed steel strip to obtain a cross-rolled steel strip; S7. Perform partial recrystallization annealing on the cross-rolled steel strip to obtain a partially recrystallized annealed steel strip; S8. Perform nitriding and isothermal homogenization on the partially recrystallized annealed steel strip to obtain a nitrided and isothermally homogenized steel strip; S9. Perform high-temperature annealing on the nitrided and isothermally homogenized steel strip to obtain the double-oriented silicon steel.

[0016] Preferably, in step S2, the hot-rolling holding temperature is 1200 - 1250 °C, the total reduction is 20 - 50%, the final hot-rolling temperature ≥ 1000 °C, and after hot-rolling, it is air-cooled to room temperature. Specifically, the heating temperature can be, for example, any one of 1200 °C, 1210 °C, 1220 °C, 1230 °C, 1240 °C, 1250 °C or the range between any two of them; the total reduction can be, for example, any one of 20%, 25%, 30%, 35%, 40%, 45%, 50% or the range between any two of them; the final rolling temperature can be, for example, any one of 1000 °C, 1010 °C, 1020 °C, 1030 °C, 1040 °C, 1050 °C, 1060 °C, 1070 °C, 1080 °C or the range between any two of them.

[0017] Preferably, in step S3, the normalizing temperature is 1080 - 1120 °C, the normalizing time is 2 - 5 min, the protective atmosphere for normalizing treatment is N 2 , and the cooling method is oil cooling. Specifically, the normalizing temperature can be, for example, any one of 1080 °C, 1090 °C, 1100 °C, 1110 °C, 1120 °C or the range between any two of them; the normalizing time can be, for example, any one of 2 min, 3 min, 4 min, 5 min or the range between any two of them.

[0018] Preferably, in step S4, the warm-rolling starting temperature is 400 - 600 °C, the total reduction is 20 - 50%, and after warm-rolling, it is air-cooled to room temperature. Specifically, the warm-rolling starting temperature can be, for example, any one of 400 °C, 450 °C, 500 °C, 550 °C, 600 °C or the range between any two of them; the total reduction can be, for example, any one of 20%, 25%, 30%, 35%, 40%, 45%, 50% or the range between any two of them.

[0019] Preferably, in the step S5, the high-temperature annealing treatment includes a first-stage annealing and a second-stage annealing; the first-stage annealing temperature is 780-850 °C, the first-stage annealing time is 2-5 min, and the first-stage annealing protective atmosphere is N 2 / H 2 a mixed gas with a volume ratio of 1 / 3; the second-stage annealing temperature is 1180-1200 °C, the second-stage annealing time is 18-25 h, and the second-stage annealing protective atmosphere is H 2 , and the cooling method for the second-stage annealing is air cooling. Specifically, the first-stage annealing temperature can be, for example, any one of 780 °C, 790 °C, 800 °C, 810 °C, 820 °C, 830 °C, 840 °C, 850 °C or the range between any two of them; the second-stage annealing temperature can be any one of 1180 °C, 1185 °C, 1190 °C, 1195 °C, 1200 °C or the range between any two of them.

[0020] Preferably, in the step S6, the rolling direction of the cross-rolled steel strip is parallel to the transverse direction of the warm-rolled steel strip, and the transverse direction of the cross-rolled steel strip is parallel to the rolling direction of the warm-rolled steel strip; the starting rolling temperature for cross-rolling is 300-500 °C, the total reduction is 50-80%, and after cross-rolling, it is air-cooled to room temperature. Specifically, the starting rolling temperature for cross-rolling can be, for example, any one of 300 °C, 350 °C, 400 °C, 450 °C, 500 °C or the range between any two of them; the total reduction can be, for example, any one of 50%, 60%, 70%, 80% or the range between any two of them.

[0021] Preferably, in the step S7, the partial recrystallization annealing temperature is 700-800 °C, the partial recrystallization annealing time is 10-60 s, the partial recrystallization annealing protective atmosphere is Ar, and the cooling method is air cooling. Specifically, the partial recrystallization annealing temperature can be, for example, any one of 700 °C, 710 °C, 720 °C, 730 °C, 740 °C, 750 °C, 760 °C, 770 °C, 780 °C, 790 °C, 800 °C or the range between any two of them. The partial recrystallization annealing time can be, for example, any one of 10 s, 20 s, 30 s, 40 s, 50 s, 60 s or the range between any two of them.

[0022] Preferably, in the step S8, the nitriding treatment temperature is 650-750 °C, the nitriding medium used for the nitriding treatment is N 2 , the nitriding treatment time is 1-5 min; the isothermal homogenization treatment temperature is 650-750 °C, the isothermal homogenization treatment time is 1-4 h, and the protective atmosphere for the isothermal homogenization treatment is N 2 / H 2The mixed gas with a volume ratio of 1 / 3 is cooled by air cooling. Specifically, the nitriding treatment temperature can be, for example, any one of 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, 710°C, 720°C, 730°C, 740°C, 750°C or the range between any two of them. The isothermal homogenization treatment temperature can be, for example, any one of 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, 710°C, 720°C, 730°C, 740°C, 750°C or the range between any two of them.

[0023] Preferably, in the step S9, the high-temperature annealing treatment includes one-stage annealing and two-stage annealing; the one-stage annealing temperature is 850 - 950°C, the one-stage annealing time is 5 - 10 min, and the one-stage annealing protective atmosphere is N 2 / H 2 mixed gas with a volume ratio of 1 / 3; the two-stage annealing temperature is 1180 - 1200°C, the two-stage annealing time is 18 - 25 h, and the two-stage annealing protective atmosphere is H 2 , and the cooling method for the two-stage annealing is air cooling. Specifically, the one-stage annealing temperature can be, for example, any one of 800°C, 810°C, 820°C, 830°C, 840°C, 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C, 950°C or the range between any two of them; the two-stage annealing temperature can be, for example, any one of 1180°C, 1185°C, 1190°C, 1195°C, 1200°C or the range between any two of them.

[0024] The present invention also provides a double-oriented silicon steel, which is prepared by using the above-mentioned preparation method of double-oriented silicon steel. By mass percentage, it includes Si: 6.3 - 6.7 wt%, Ce: 0.001 - 0.005 wt%, Al: 0.01 - 0.03 wt%, N: 0.005 - 0.009 wt%, S < 0.005 wt%, P < 0.008 wt%, and the balance is Fe and inevitable impurity elements.

[0025] The Si element improves the resistivity of the electrical steel, reduces the iron loss, and determines the basic magnetic properties of the electrical steel. When the Si content is increased to 6.5 wt%, the high-frequency iron loss of the electrical steel is significantly reduced, and the saturation magnetostriction is close to zero. When the Si content is lower than 6.3 wt%, the high-frequency iron loss and saturation magnetostriction increase; when the Si content is higher than 6.7 wt%, the medium-temperature rolling plasticity is close to zero, resulting in rolling edge cracking or even cracking.

[0026] Due to its high reducibility, Ce element combines with O and S during the smelting process to form rare earth oxides and rare earth sulfides, reducing the content of free O and S in the molten steel. In addition, Ce element can refine the solidification structure of strip continuous casting and reduce the matrix order degree, improving the rolling plasticity of the cast strip. When the Ce content is lower than 0.001wt%, the removal effect of O and S in the molten steel is low, and the refining effect of the cast strip structure is insufficient; when the Ce content is higher than 0.005wt%, Ce element segregation appears at the dendrite boundaries of the cast strip, reducing the element distribution and tissue uniformity.

[0027] Al element has a similar effect to Si element in increasing the resistivity, and Al element is a component element of the AlN inhibitor. The AlN particles precipitated from the matrix are used to pin the grain boundaries, inhibit the growth of most recrystallized grains, and promote secondary recrystallization. When the Al content is lower than 0.01wt%, the precipitation amount of AlN is small, and the pinning effect of the inhibitor is insufficient; when the Al content is higher than 0.03wt%, the surface quality of the high-temperature annealed steel strip decreases, the precipitation amount of AlN particles is large, the grain boundary pinning effect is too high, the grain boundary migration ability decreases, and the secondary recrystallization is imperfect.

[0028] N element is a component element of the AlN inhibitor. When the N content is lower than 0.005wt%, the precipitation amount of AlN is small, and the pinning effect of the inhibitor is insufficient; when the N content is higher than 0.009wt%, the precipitation amount of AlN particles is large, and the secondary recrystallization is imperfect.

[0029] S and P elements belong to grain boundary segregation elements, reducing the hot workability of the material, so the content should be as low as possible.

[0030] Preferably, the thickness of the double-oriented silicon steel is 0.15 - 0.5 mm, and the width is 150 - 500 mm. The rolling direction magnetic induction intensity B 8 ≥1.60 T, the transverse magnetic induction intensity B 8 ≥1.55 T, the iron loss P 10 / 400 ≤11.00 W / kg, the iron loss P 2 / 1000 ≤2.00 W / kg, the saturation magnetostriction λs ≤ 0.9×10 -6 .

[0031] The technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0032] Example 1 A preparation method of double-oriented silicon steel includes the following steps: S1. Smelt the cerium-containing double-oriented silicon steel molten steel and obtain a cast strip through strip continuous casting; S2. Using the as-cast strip as raw material, heat, hot-roll and pickling the as-cast strip to obtain a hot-rolled strip. The heating temperature is 1200 °C, the total reduction is 30%, the finishing rolling temperature is 1050 °C, and after hot rolling, it is air-cooled to room temperature.

[0033] S3. Normalize the hot-rolled strip; the normalizing temperature is 1100 °C, the normalizing time is 3 min, and the protective atmosphere for normalizing treatment is N 2 , and the cooling method is oil cooling.

[0034] S4. Warm-roll the normalized steel strip to obtain a warm-rolled steel strip; the warm-rolling starting temperature is 450 °C, the total reduction is 40%, and after warm rolling, it is air-cooled to room temperature.

[0035] S5. Perform high-temperature annealing on the warm-rolled steel strip to obtain a high-temperature annealed steel strip; the first-stage annealing temperature for high-temperature annealing treatment is 800 °C, the first-stage annealing time is 4 min, and the protective atmosphere for the first-stage annealing is N 2 / H 2 mixed gas with a volume ratio of 1 / 3; the second-stage annealing temperature for high-temperature annealing treatment is 1200 °C, the second-stage annealing time is 20 h, and the protective atmosphere for the second-stage annealing is H 2 , and the cooling method for the second-stage annealing is air cooling.

[0036] S6. Cross-roll the high-temperature annealed steel strip to obtain a cross-rolled steel strip; the rolling direction of the cross-rolled steel strip is parallel to the transverse direction of the warm-rolled steel strip, and the transverse direction of the cross-rolled steel strip is parallel to the rolling direction of the warm-rolled steel strip. The starting temperature for cross-rolling is 400 °C, the total reduction is 60%, and after cross-rolling, it is air-cooled to room temperature.

[0037] S7. Perform partial recrystallization annealing treatment on the cross-rolled steel strip to obtain a partially recrystallized annealed steel strip; the partial recrystallization annealing temperature is 700 °C, the partial recrystallization annealing time is 30 s, the protective atmosphere for partial recrystallization annealing is Ar, and the cooling method is air cooling.

[0038] S8. Perform nitriding and isothermal homogenization treatment on the partially recrystallized annealed steel strip to obtain a nitrided and isothermally homogenized steel strip; the nitriding treatment temperature is 650 °C, the nitriding medium used for nitriding treatment is N 2 , the nitriding treatment time is 4 min; the isothermal homogenization treatment temperature is 700 °C, the isothermal homogenization treatment time is 2 h, and the protective atmosphere for isothermal homogenization treatment is N 2 / H 2 mixed gas with a volume ratio of 1 / 3, and the cooling method is air cooling.

[0039] S9. Anneal the nitrided and isothermally homogenized steel strip at high temperature to obtain the double-oriented silicon steel. The annealing temperature in the first stage of the high-temperature annealing treatment is 900 °C, the annealing time in the first stage is 8 min, and the protective atmosphere in the first stage of annealing is a mixed gas of N 2 / H 2 with a volume ratio of 1 / 3; the annealing temperature in the second stage of the high-temperature annealing treatment is 1200 °C, the annealing time in the second stage is 20 h, and the protective atmosphere in the second stage of annealing is H 2 , and the cooling method in the second stage of annealing is air cooling.

[0040] The physical diagram of the double-oriented silicon steel prepared in this example is as shown in Figure 1 and its composition is shown in Table 1.

[0041] Table 1 Composition of the double-oriented silicon steel in this example (wt%) Example 2 The difference from Example 1 is that in step S6, the total reduction in cross rolling is 80%.

[0042] Comparative Example 1 The difference from Example 1 is that the Si content is 6.03 wt%.

[0043] Comparative Example 2 The difference from Example 2 is that the N content is 0.011 wt%.

[0044] Comparative Example 3 The difference from Example 1 is that in step S4, the starting rolling temperature in warm rolling is 650 °C.

[0045] Comparative Example 4 The difference from Example 1 is that in step S6, the cross rolling temperature is 550 °C.

[0046] Comparative Example 5 The difference from Example 1 is that in step S7, the partial recrystallization annealing temperature is 850 °C and the annealing time is 2 min.

[0047] Comparative Example 6 The difference from Example 1 is that in step S8, the nitriding treatment temperature is 570 °C and the isothermal homogenization treatment temperature is 620 °C.

[0048] Comparative Example 7 The difference from Example 1 is that in step S9, the annealing temperature in the first stage of high-temperature annealing is 980 °C.

[0049] Comparative Example 8 It is different from Example 1 in that the Ce content is 0.008 wt%.

[0050] Comparative Example 9 It is different from Example 1 in that the Al content is 0.005 wt%.

[0051] The properties of the double-oriented silicon steel obtained in the examples and comparative examples of the present invention were detected, and the results are shown in Table 2.

[0052] Table 2 Properties of double-oriented silicon steel obtained in examples and comparative examples As can be seen from Table 2, the examples of the present invention have higher rolling and transverse magnetic induction intensities compared with the comparative examples, and maintain lower medium-frequency and high-frequency iron losses, lower saturation magnetostriction coefficients, and better comprehensive magnetic properties. This is because, according to steps S1-S5 of the present invention, a Goss secondary recrystallization structure can be prepared. In step S6, the preferred orientation law of the deformed sub-grains of the rotating Goss intragranular shear band is used to increase the number of cubic grain seeds. Steps S7-S9 promote the abnormal growth of {001}<100> oriented grains, thereby obtaining double-oriented silicon steel with better comprehensive magnetic properties. The present invention utilizes the "short process" and "near-net shape" characteristics of the thin strip continuous casting technology, which can reduce the total rolling reduction of manufacturing electrical steel sheets, facilitate the control of rolling cracking and texture regulation, and can improve the rolling plasticity of double-oriented silicon steel at medium temperatures (300-600 °C). With the rapid development of the domestic new energy vehicle industry, the market demand for drive motors and on-vehicle transformers increases year by year, and the operating environment tends to be high-frequency. Carrying out the manufacturing and theoretical research of the double-oriented silicon steel described in the present invention and developing core materials for drive motors and on-vehicle transformers suitable for high-frequency service environments are of great significance for the development and technological iteration of the new energy vehicle industry.

[0053] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made using the content of the specification of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A method for preparing dual-oriented silicon steel, characterized in that: The steps include: S1. Smelting to obtain dual-oriented silicon steel molten steel, wherein the Si content in the molten steel is 6.3-6.7wt%, and the Ce content is 0.001-0.005%; and obtaining a cast strip by thin strip continuous casting; S2, hot rolling the cast strip to obtain a hot rolled strip; S3, performing normalizing treatment on the hot-rolled strip to obtain a normalized steel strip; S4, warm rolling the normalized steel strip to obtain a warm rolled steel strip; S5, performing high temperature annealing on the warm rolled steel strip to obtain a high temperature annealed steel strip; S6, cross-rolling the high temperature annealed steel strip to obtain a cross-rolled steel strip; S7, performing partial recrystallization annealing treatment on the cross-rolled steel strip to obtain a partially recrystallized annealed steel strip; S8, performing nitriding and isothermal homogenization treatment on the partially recrystallized annealed steel strip to obtain a nitrided and isothermal homogenized steel strip; S9, performing high temperature annealing treatment on the nitrided and isothermal homogenized steel strip to obtain the dual-oriented silicon steel.

2. The method for preparing dual-oriented silicon steel according to claim 1, characterized in that: In the step S2, the hot rolling holding temperature is 1200-1250°C, the total reduction is 20-50%, the hot rolling final rolling temperature is ≥1000°C, and the hot rolling is followed by air cooling to room temperature.

3. The method for preparing dual-oriented silicon steel according to claim 1, characterized in that: In step S3, the normalization temperature is 1080-1120° C., the normalization time is 2-5 min, the normalization treatment protective atmosphere is N 2 , and the cooling method is oil cooling.

4. The method for preparing dual-oriented silicon steel according to claim 1, characterized in that: In step S4, the warm rolling start temperature is 400-600° C., the total reduction is 20-50%, and the steel is air-cooled to room temperature after warm rolling.

5. The method for preparing dual-oriented silicon steel according to claim 1, characterized in that: In the step S5, the high temperature annealing treatment includes one-stage annealing and two-stage annealing; the temperature of the first-stage annealing is 780-850°C, the time of the first-stage annealing is 2-5min, and the protective atmosphere of the first-stage annealing is a mixed gas with a volume ratio of N2 / H2=1 / 3; the temperature of the second-stage annealing is 1180-1200°C, the time of the second-stage annealing is 18-25h, the protective atmosphere of the second-stage annealing is H2, and the cooling method of the second-stage annealing is air cooling.

6. The method for preparing dual-oriented silicon steel according to claim 1, characterized in that: In the step S6, the rolling direction of the cross-rolled steel strip is parallel to the transverse direction of the warm-rolled steel strip, and the transverse direction of the cross-rolled steel strip is parallel to the rolling direction of the warm-rolled steel strip; the starting rolling temperature of the cross-rolling is 300-500°C, the total reduction is 50-80%, and the cross-rolling is air-cooled to room temperature.

7. The method for preparing dual-oriented silicon steel according to claim 1, characterized in that: In the step S7, the partial recrystallization annealing temperature is 700-800°C, the partial recrystallization annealing time is 10-60s, the partial recrystallization annealing protective atmosphere is Ar, and the cooling method is air cooling; in the step S8, the nitriding treatment temperature is 650-750°C, the nitriding medium used for the nitriding treatment is N2, and the nitriding treatment time is 1-5min; the isothermal homogenization treatment temperature is 650-750°C, the isothermal homogenization treatment time is 1-4h, the isothermal homogenization treatment protective atmosphere is a mixed gas with a volume ratio of N2 / H2=1 / 3, and the cooling method is air cooling.

8. The method for preparing dual-oriented silicon steel according to claim 1, characterized in that: In the step S9, the high temperature annealing treatment includes one-stage annealing and two-stage annealing; the temperature of the first-stage annealing is 850-950°C, the time of the first-stage annealing is 5-10min, and the protective atmosphere of the first-stage annealing is a mixed gas with a volume ratio of N2 / H2=1 / 3; the temperature of the second-stage annealing is 1180-1200°C, the time of the second-stage annealing is 18-25h, the protective atmosphere of the second-stage annealing is H2, and the cooling method of the second-stage annealing is air cooling.

9. A dual-oriented silicon steel, characterized in that: The double-oriented silicon steel is prepared by the preparation method of any one of claims 1 to 8, and comprises, by mass percentage, Si: 6.3-6.7wt%, Ce: 0.001-0.005wt%, Al: 0.01-0.03wt%, N: 0.005-0.009wt%, S<0.005wt%, P<0.008wt%, and the balance is Fe and unavoidable impurity elements.

10. The dual-oriented silicon steel according to claim 9, characterized in that: The thickness of the dual-oriented silicon steel is 0.15-0.5 mm, and the width is 150-500 mm; the rolling magnetic induction intensity B8 of the dual-oriented silicon steel is ≥1.60 T, the transverse magnetic induction intensity B8 is ≥1.55 T, and the iron loss P 10 / 400 ≤11.00W / kg, iron loss P 2 / 1000 ≤2.00W / kg, saturation magnetostriction λs≤0.9×10 -6 .

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