Low-anisotropy non-oriented silicon steel and production method thereof

Abstract

The invention discloses low-anisotropy non-oriented silicon steel and a production method thereof, and relates to the technical field of non-oriented silicon steel manufacturing. The non-oriented silicon steel comprises the following chemical components in percentage by weight: less than or equal to 0.0035% of C, 0.25-3.5% of Si, 0.15-0.55% of Mn, 0.10-1.15% of Als, less than or equal to 0.1% of P, less than or equal to 0.01% of S, less than or equal to 0.02% of N, less than or equal to 0.02% of Ti, less than or equal to 0.0070% of O and the balance of Fe and inevitable impurities. The production method comprises the steps of continuous casting, hot rolling, acid pickling, cold rolling and annealing. By ensuring the total reduction rate of cold rolling and controlling the annealing process, no expensive alloy needs to be added, and by controlling the components and improving the process, the anisotropy is reduced while the iron loss, magnetic induction and mechanical properties of the product are ensured; wherein the iron loss P1.5 / 50 anisotropy is less than or equal to 12%, the magnetic induction B50 anisotropy is less than or equal to 1.5%, the mechanical yield strength Rp0.2 anisotropy is less than or equal to 3.0%, and the tensile strength Rm anisotropy is less than or equal to 2.0%.

Description

Technical Field

[0001] The invention relates to the technical field of non-oriented silicon steel manufacturing, in particular to low anisotropic non-oriented silicon steel and a production method thereof. Background Art

[0002] Non-oriented silicon steel sheets are widely used in the production of core materials such as brushless DC motors, AC induction motors and industrial motors in the fields of aerospace, medical, chemical, machinery, and home appliances. With the increase in energy efficiency levels, it is imperative to reduce carbon emissions and improve the working efficiency of motors. Some motors working under rotating conditions have a speed of up to 28,000 r / min, which requires the material to be isotropic. The anisotropy of product performance includes magnetic (performance) anisotropy and mechanical (performance) anisotropy. The lower the magnetic anisotropy, the better the material performance and the higher the working efficiency. The lower the mechanical anisotropy, the similar strength, uniformity and ductility of the material in all directions. In order to extend the service life of the motor, it is necessary to improve the material's use efficiency and processing performance while ensuring that it is not easy to produce warping and edge cracks when subjected to huge centrifugal forces during high-speed rotation, thereby reducing fatigue damage.

[0003] At present, the national standard "GB / T2521.1-2016 Full process cold-rolled electrical steel Part 1: Grain non-oriented steel strip (sheet)" stipulates that the characterization method of magnetic anisotropy is: The magnetic anisotropy of high-grade non-oriented silicon steel is required to be ≤17%. The magnetic anisotropy of high-grade non-oriented silicon steel widely used in the market is 12-13%.

[0004] Texture is the intrinsic reason for the anisotropy of products. Different production methods result in different main components and proportions of the main texture in different directions, which leads to different product performance in each direction, that is, anisotropy exists. Improving the favorable texture components and proportions in non-oriented silicon steel and reducing unfavorable textures are effective means to reduce anisotropy.

[0005] The Chinese invention patent with application number 202010393939.4 discloses a low anisotropic non-oriented silicon steel for hydropower generation and a production method thereof. Its chemical composition is Si: 2.8-3.2%, Mn: 0.1-0.3%, Als: 0.5-0.8%, B: 0.0010%-0.0025%, Cu: 0.01%-0.02%. By adding B and Cu elements, a non-oriented silicon steel with low magnetic anisotropy is produced, but its production cost is significantly increased.

[0006] The Chinese invention patent with application number 201910938869.3 discloses a method for improving the magnetic anisotropy of high-grade non-oriented silicon steel. By changing the hot rolling and rough rolling method, a 1+3 rolling method is adopted to obtain a specific crystal structure and texture component, while optimizing the annealing tension and reducing the annealing speed to 65-75m / min to improve the magnetic anisotropy. This invention is suitable for high-grade silicon steel, but due to the low annealing speed, it may bring about surface oxidation, low production efficiency and other undesirable effects in actual production.

[0007] The Chinese invention patent with application number 201810081918.1 discloses a method for preparing low magnetic anisotropic non-oriented silicon steel by thin strip continuous casting. The method mainly adopts thin strip continuous casting technology, controls hot rolling reduction rate and other processes, and adds elements such as Sn to achieve the purpose of producing low magnetic anisotropic non-oriented silicon steel. This invention is only applicable to non-oriented silicon steel with a silicon content of less than 2.0%, and is not suitable for large-scale production processes of conventional equipment. At the same time, due to the addition of rare earth elements, the cost of obtaining low-grade silicon is relatively high.

[0008] The Chinese invention patent with application number 202010472318.5 discloses a low-cost, ultra-low-aluminum non-oriented electrical steel sheet, with a chemical composition of 0.1-1.2% Si, 0.1-0.5% Mn, 0.01-0.2% P, 0.005-0.05% Sn, and Als ≤ 0.001%. The steel contains an extremely low aluminum content, and the steel and slag contain a moderate amount of oxidizing technology. The quality of the special alloy for RH refining, deoxidation, and alloying is lowered to significantly reduce the manufacturing cost of the steel. The solution adds the alloy Sn element, which increases the cost. Summary of the invention

[0009] In order to overcome the shortcomings of the above-mentioned technology, the purpose of the present invention is to provide a low anisotropy non-oriented silicon steel and a production method thereof, so as to solve the problem of high anisotropy of non-oriented silicon steel products, without adding expensive alloys, and through the control of composition and improvement of process, the anisotropy can be reduced while ensuring the iron loss, magnetic induction and mechanical properties of the product.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] The invention discloses a low anisotropic non-oriented silicon steel, which is special in that it comprises the following chemical components in weight percentage: Si 0.25%-3.5%, Mn 0.15%-0.55%, Als 0.10%-1.15%.

[0012] Si, Mn, Als: They are alloying elements in non-oriented silicon steel. With the increase of total content, the resistivity of silicon steel increases and the iron loss decreases. However, with the increase of Si, Mn and Als alloying element content, not only the hardness of the steel plate increases, which is not conducive to rolling, but also the anisotropy increases. Therefore, Si shall not exceed 3.5%, Mn shall not exceed 0.55%, and Als shall not exceed 1.15%.

[0013] C, S, N, O and Ti: They are all harmful impurity elements in silicon steel. The increase of their content will lead to the increase of non-metallic inclusions in non-oriented silicon steel and a significant increase of iron loss. In principle, the lower the content of harmful elements, the better.

[0014] As a preferred embodiment, the non-oriented silicon steel includes the following chemical components in weight percentage: C≤0.0035%, Si 0.25%~3.5%, Mn 0.15%~0.55%, Als 0.10%~1.15%, P≤0.1%, S≤0.01%, N≤0.02%, Ti≤0.02%, O≤0.0070%, and the rest is Fe and unavoidable impurities.

[0015] The present invention also provides a method for producing low anisotropic non-oriented silicon steel, which is special in that it includes continuous casting, hot rolling, pickling, cold rolling and annealing; the hot rolling includes heating, rolling and coiling.

[0016] As a preferred solution, during the continuous casting process, the molten steel is cast into a slab with a thickness of 150 to 250 mm; after continuous casting, the slab enters the heating process, the heating temperature is 1000 to 1180° C., and the soaking time is 120 to 210 min.

[0017] As a preferred solution, during the rolling process, the ingot is roughly rolled to a thickness of 28 mm to 40 mm and then fine rolled; the final rolling temperature is 810 to 920° C.; the thickness of the hot-rolled plate after fine rolling is controlled according to the following formula:

[0018]

[0019] Among them, d 热 is the thickness of hot rolled plate, d 成 is the thickness of finished steel. The thickness of hot rolled plate d 热 Strictly according to the thickness of the finished board 成 To determine, in order to ensure that the total cold rolling reduction rate is within the medium reduction rate range of 50% to 80%.

[0020] As a preferred solution, during the coiling process, the coiling temperature is 560-710° C. During hot rolling, a hot coil box is used, and the rough rolling is rolled to 28 mm-40 mm, and a total of 7 stands F1-F7 are put into use for finishing rolling.

[0021] As a preferred solution, it also includes: when Σ wt When (Si+Al)>2.0%, the hot rolled coil is normalized and then pickled, the normalization temperature is 800-1000℃, and the normalization time is 2-5min; Si and Al represent the weight percentage of the corresponding chemical elements in the steel product. The normalization treatment ensures that the steel has a larger equiaxed grain structure before cold rolling.

[0022] As a preferred solution, the cold rolling process uses a single cold rolling process to cold roll the pickled hot-rolled sheet to the thickness of finished steel; the finished steel thickness is 0.25-0.65 mm, and the total cold rolling reduction is 50%-80%. A large amount of shear band structure will be retained in the cold-rolled sheet structure within this reduction range, which will become the nucleation position of the favorable texture during the subsequent recrystallization nucleation, thereby increasing the component and strength of the favorable texture.

[0023] As a preferred solution, the annealing process is carried out in an annealing furnace, the process section running speed is 100-150m / min, the protective atmosphere in the furnace is a nitrogen-hydrogen mixed gas, the dew point in the furnace is controlled below -10°C, and the tension in the furnace is 1.0-2.0KN.

[0024] As a preferred embodiment, during the annealing process, the cold-rolled sheet is heated to 730-900°C and kept at this temperature for 29-44 seconds, and then continued to be heated to the aquifer temperature and kept at this temperature for 10-30 seconds; the aquifer temperature T 均 The temperature is 830-990℃ and controlled according to the following formula:

[0025] T 均 (℃)≤-59954.88×[Σ wt (Si+Al)] 2 +8061.347×[Σ wt (Si+Al)]+813.12,

[0026] Among them, Si and Al represent the weight percentage of the corresponding chemical elements in the steel products.

[0027] During the heating process of annealing, the high deformation energy storage after cold rolling is used to start the nucleation and recrystallization process while decarburizing and annealing. Due to the low temperature of 730-900℃, the random textures of various orientations are fully nucleated and grown, thereby reducing the proportion of unfavorable textures. After the insulation, it is quickly heated to a higher temperature of 830℃-990℃, and then the insulation is carried out to promote the crystal nuclei of the random texture in the front to obtain energy and grow further, so that the components and proportions of the random texture increase, and the components and proportions of the unfavorable texture decrease. After annealing, an insulating coating is applied to the surface of the strip, and it is dried and solidified at a temperature below 500℃ to obtain excellent insulation properties.

[0028] Ambient temperature T 均(℃), generally with the alloy composition Σ wt The higher the annealing temperature, the lower the proportion and strength of the unfavorable texture in the organization. However, when the temperature is higher than a certain level, it will increase instead. Therefore, the soaking temperature should be as high as possible but not exceed the above formula.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The low anisotropic non-oriented silicon steel and the production method thereof of the present invention do not need to add expensive alloys, and through the control of components and the improvement of processes, the anisotropy of various properties is reduced while the iron loss, magnetic induction and mechanical properties of the product are guaranteed.

[0031] The present invention manufactures hot-rolled coils with ultra-thin thickness specifications, maintains the total cold rolling reduction rate within the range of 50% to 80%, adopts a one-time cold rolling method to cold-roll the hot-rolled plate to different thicknesses, and then in the subsequent annealing process, first quickly heats to a certain slightly lower temperature and then holds the temperature for a period of time to increase the component and randomness of the texture, reduce the component and strength of the unfavorable texture, so that the random texture grains are nucleated and grown, and then quickly heats to a higher temperature and holds the temperature for a period of time, so that the original random texture grains can fully grow and homogenize the organization, reduce the component and proportion of the unfavorable texture in the finished product, and finally obtains the product. The iron loss, magnetic induction and mechanical transverse and longitudinal anisotropy can be reduced by 20% or more, and the iron loss P 1.5 / 50 Anisotropy ≤12%, magnetic induction B 50 Anisotropy ≤1.5%, mechanical yield strength Rp0.2 anisotropy ≤3.0%, tensile strength Rm anisotropy ≤2.0%. It can be used in the manufacture of motors with high speed requirements and effectively extend the service life of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the metallographic microstructure diagram of the normalized plate in Example 2;

[0033] Figure 2 is the metallographic microstructure diagram of the cold-rolled sheet in Example 2;

[0034] Figure 3 The microstructure of the shear band of the cold rolled plate detected by EBSD in Example 2 ODF graph of

[0035] Figure 4 This is a metallographic microstructure diagram of the steel coil product in Example 2;

[0036] Figure 5 Macro texture of the steel coil product detected by XRD in Example 2 ODF graph of . DETAILED DESCRIPTION

[0037] In order to better explain the present invention, the main contents of the present invention are further explained below in conjunction with the drawings and specific embodiments, but the contents of the present invention are not limited to the following embodiments.

[0038] The invention discloses a low anisotropic non-oriented silicon steel, the element contents of which are as follows by weight percentage: C≤0.0035%, 0.25%≤Si≤3.5%, 0.15%≤Mn≤0.55%, 0.10%≤Als≤1.15%, P≤0.1%, S≤0.01%, N≤0.02%, Ti≤0.02%, O≤0.0070%, and the rest are Fe and unavoidable impurities.

[0039] The production method of the above-mentioned low anisotropy non-oriented silicon steel includes: molten steel with chemical composition meeting the requirements is subjected to continuous casting, heating, rolling, coiling, normalization (normalization is not required in some cases), pickling, cold rolling and annealing to produce non-oriented silicon steel finished products.

[0040] Continuous casting: The molten steel that meets the requirements is continuously cast into 150-250mm billets;

[0041] Heating: The continuously cast slab is heated to 1000-1180°C, with a soaking time of 120 min ≤ ≤ 210 min.

[0042] Hot rolling and coiling: The hot rolling final rolling temperature is 810℃~920℃, and the hot rolled plate with a thickness of 1.2mm~2.6mm is processed, and the coiling temperature is 560℃~710℃ to be coiled into the cold rolled raw plate;

[0043] According to the thickness of hot rolled plate d 热 Strictly according to the thickness of the finished board 成 To ensure that the total cold rolling reduction is within the medium range of 50% to 80%. When the finished product is thin, in order to ensure that the total cold rolling reduction is within the range of 50% to 80%, hot coil boxes are used during hot rolling, and the rough rolling is rolled to 28mm to 40mm, and all 7 stands of finishing rolling F1 to F7 are put into use.

[0044] Normalizing: Normalizing treatment is generally carried out at a temperature of 800-1000°C for 2-5 minutes to ensure that there is a large equiaxed grain structure before cold rolling. wt When (Si+Al)≤2.0%, the product does not need to be normalized.

[0045] Pickling and cold rolling: After hot rolling and coiling, the hot rolled coil or normalized plate after normalization is pickled with hydrochloric acid, and then the pickled steel plate is cold rolled to a thickness of 0.25mm to 0.65mm by a single cold rolling method. In order to ensure that the total reduction rate is within the range of 50% to 80% after single cold rolling, the thickness of the finished plate must be strictly controlled according to the thickness of the finished plate.成 To confirm the thickness of the hot rolled plate 热 ,satisfy:

[0046]

[0047] Annealing: The cold rolled sheet is annealed in an annealing furnace at a process speed of 100-150 m / min. The heating speed of the conventional annealing process is maintained, firstly rapidly heated to 730-900°C, kept at this temperature for 29s-44s, and then rapidly heated to a higher soaking temperature T 均 =830℃~990℃, keep warm for 10s~30s; the atmosphere in the annealing furnace is H2 and N2 in a ratio of 3:7 as a protective atmosphere, the dew point in the furnace is controlled below -10℃, the tension in the furnace is in the range of 1.0~2.0KN, and then an insulating coating is applied on the surface of the strip, and it is dried and cured at a temperature below 500℃ to obtain excellent insulation performance;

[0048] During the annealing process, the holding temperature is T 均 (℃) generally varies with alloy composition Σ wt (Si+Al) varies. The higher the annealing temperature, the lower the proportion and strength of the unfavorable texture in the organization. However, when the temperature is higher than a certain level, it will increase. Therefore, the soaking temperature should be as high as possible but not exceed the maximum, that is, it must meet the following requirements:

[0049] T 均 (℃)≤-59954.88×[Σ wt (Si+Al)] 2 +8061.347×[Σ wt (Si+Al)]+813.12,

[0050] Among them, Si and Al represent the weight percentage of the corresponding chemical elements in the steel products.

[0051] The present invention is further described below by Examples 1 to 2 and Comparative Examples 1 to 6. The chemical composition and weight percentage of the steel coil products in Examples 1 to 2 and Comparative Examples 1 to 6 are shown in Table 1, with the remainder being Fe and unavoidable impurities.

[0052] Example 1

[0053] A method for producing low anisotropic non-oriented silicon steel, the chemical composition mass percentage of the steel is shown in Table 1. The production method comprises the following process steps:

[0054] Continuous casting: The molten steel that meets the requirements is continuously cast into 180mm ingots;

[0055] Hot rolling: The ingot is heated and hot rolled by hot charging, with the heating soaking temperature of 1140℃ and soaking time of 200min. The ingot is roughly rolled to a thickness of 28mm, and then hot rolled into a hot coil box with all 7 stands put into use. After final rolling at 860℃ and coiling at 690℃, an ultra-thin hot rolled plate with a thickness of 1.6mm is obtained.

[0056] Pickling and cold rolling: After pickling, the ultra-thin hot-rolled plate is cold-rolled to a thickness of 0.50 mm, with a total reduction rate of 68.75%;

[0057] Annealing: Annealing in an annealing furnace, annealing tension 1.6KN, process speed 120m / min, first quickly heated to 800℃, kept warm for 32s and then heated to T again 均 =890℃, heat-maintaining for 15s, H2 and N2 in a ratio of 3:7 as protective atmosphere, and the dew point in the furnace is controlled below -10℃.

[0058] Example 2

[0059] A method for producing low anisotropic non-oriented silicon steel, the chemical composition mass percentage of the steel is shown in Table 1. The production method comprises the following process steps:

[0060] Continuous casting: The molten steel that meets the requirements is continuously cast into 150mm ingots;

[0061] Hot rolling: The ingot is heated and hot rolled by hot charging, with a heating soaking temperature of 1110°C and a heating time of 200 min. The ingot is roughly rolled to a thickness of 28 mm, and then hot rolled into a hot coil box with all 7 stands in operation. After final rolling at 860°C and coiling at 650°C, an ultra-thin hot rolled plate with a thickness of 1.2 mm is obtained.

[0062] Normalization: The hot rolled plate is normalized at 860℃ for 2min to obtain a normalized plate;

[0063] Pickling and cold rolling: After pickling, cold rolling to 0.30mm thick cold rolled plate, the total reduction rate is 75%;

[0064] Annealing: The cold rolled sheet is annealed in an annealing furnace with an annealing tension of 1.4 KN and a process speed of 120 m / min. First, it is rapidly heated to 850°C, kept at this temperature for 32 seconds, and then heated again to the uniform temperature T 均 =990℃, heat-maintaining for 15s, H2 and N2 in a ratio of 3:7 as protective atmosphere, and the dew point in the furnace is controlled below -10℃.

[0065] Comparative Example 1

[0066] The difference from Example 1 is that in the production process, the hot rolled plate has a thickness of 2.8 mm, is cold rolled to 0.50 mm once, and the total reduction ratio of the cold rolling once is 82%, which exceeds the required medium reduction ratio range.

[0067] Comparative Example 2

[0068] The difference from Example 1 is that in the production process, the annealing process is firstly rapidly heated to 880° C. and then kept warm for 45 seconds, without a subsequent rapid heating and keeping warm process.

[0069] Comparative Example 3

[0070] The difference from Example 1 is that in the production process, the hot-rolled plate has a thickness of 2.8 mm, is cold-rolled to 0.50 mm once, and the total reduction rate of the cold rolling is 82%, which exceeds the required medium reduction rate range. In the subsequent annealing, it is first rapidly heated to 880°C and then kept warm for 45 seconds, without a subsequent rapid heating and keeping warm process.

[0071] Comparative Example 4

[0072] The difference from Example 2 is that in the production process, the hot rolled plate has a thickness of 2.0 mm, is cold rolled to 0.30 mm, and the total reduction ratio of the cold rolling is 86%, which exceeds the required medium reduction ratio range.

[0073] Comparative Example 5

[0074] The difference from Example 2 is that in the production process, the annealing process is to first rapidly heat to 1000° C. and then keep warm for 45 seconds, without a subsequent rapid heating and keeping warm process.

[0075] Comparative Example 6

[0076] The difference from Example 2 is that in the production process, the hot-rolled plate has a thickness of 2.0 mm, and is cold-rolled to 0.30 mm once. The total reduction rate of the cold rolling is 86%, which exceeds the required medium reduction rate range. In the subsequent annealing process, rapid heating to 1000°C is adopted, and then insulation for 45 seconds is adopted, without a subsequent rapid heating and insulation process.

[0077] Table 1: Chemical composition of steel products (wt%)

[0078]

[0079] The finished product properties of the steel products in Examples 1 to 2 and Comparative Examples 1 to 6 are shown in Table 2. The metallographic structure diagram of the steel plates in each process section in Example 2 is shown in Table 2. Figures 1 to 4 The calculation method of mechanical anisotropy refers to magnetic anisotropy.

[0080] Table 2: Product properties of steel products in Examples 1 to 2 and Comparative Examples 1 to 6

[0081]

[0082] As shown in Table 2, among the various properties of the steel products in Examples 1 to 2: iron loss P 1.5 / 50 The anisotropy is less than 5W / kg, and the anisotropy is less than 10%. Compared with the material with an iron loss anisotropy of 12-13% widely used in the market, the anisotropy is reduced by more than 16%. In particular, the iron loss anisotropy in Example 1 is even smaller, only 4.5%, and the anisotropy is reduced by more than 60%; the magnetic induction performance B 50 All are greater than 1.6T, and the anisotropy is less than 1.5%.

[0083] The present invention is the first to characterize and calculate the anisotropy of the mechanical properties of non-oriented silicon steel sheets. In the embodiments, the mechanical yield strength Rp0.2 is greater than 200MPa, and the anisotropy is less than 1.5%; the tensile strength Rm is greater than 350MPa, and the anisotropy is less than 1.5%. It can be seen that the non-oriented silicon steel coil product obtained by the steel composition and production process of the present invention has excellent mechanical anisotropy while having good magnetic induction properties and mechanical properties.

[0084] like Figures 1 to 4 As shown, in Example 2, after the normalizing process, the hot-rolled plate has a large equiaxed grain structure, such as Figure 1 As shown in the figure, the structure type is ferrite, and the average grain size is 82.9μm. After one cold rolling, a large amount of shear band structure is retained in the cold rolled sheet structure, such as Figure 2 As shown in the figure, the black dotted arrows at a certain angle to the rolling direction indicate shear band structures. Figure 3 The corresponding tissue texture diagram is shown in Figure 3 It can be seen that the main texture type of shear band organization is anti-Goss{110} <110> Orientation and S texture, obviously do not contain unfavorable {111} texture, which is conducive to reducing the excessive unfavorable {111} oriented texture in subsequent annealing for recrystallization nucleation and growth. In the annealing process, after the first heating and heat preservation, the higher deformation energy storage after cold rolling starts the nucleation and recrystallization process. Due to the low temperature insulation, the random textures of various orientations fully nucleate and grow, thereby reducing the proportion of unfavorable textures. During the second heating and heat preservation, the crystal nuclei of the random texture in the front gain energy and grow further, so that the components and proportions of the random texture increase, such as Figure 4 As shown, the finished product structure is ferrite with an average grain size of 92.1μm. Figure 5 The corresponding tissue texture diagram is shown in Figure 5 It can be seen that there is no strong and obvious unfavorable γ texture channel in the finished plate.

[0085] In Comparative Examples 1 to 6, the mechanical yield strength Rp0.2 anisotropy of Comparative Example 1 is significantly greater than that of Example 1 due to the excessively high total cold rolling reduction rate. In Comparative Example 2, since the annealing process of the present invention is not adopted, the anisotropy of various properties is relatively large. In Comparative Example 3, the total cold rolling reduction rate is too high and the annealing process of the present invention is not adopted, and the anisotropy of various properties is greater than that of Comparative Example 2. Similarly, the performance results of the steel products in Comparative Examples 4 to 6 show the same trend as that in Example 2.

[0086] It can be seen that the present invention manufactures ultra-thin hot-rolled coils, adopts a one-time cold rolling method to keep the total cold rolling reduction rate in the range of 50% to 80%, and cold-rolls the hot-rolled plate to different thicknesses. Then, in the subsequent annealing process, it is first quickly heated to a certain slightly lower temperature and then kept warm for a period of time to increase the component and randomness of the texture, reduce the component and strength of the unfavorable texture, so that the random texture grains are nucleated and grown, and then quickly heated to a higher temperature and then kept warm for a period of time, so that the original random texture grains can fully grow and homogenize the organization, reduce the component and proportion of the unfavorable texture in the finished product, and finally obtain The product has very low iron loss, magnetic induction and mechanical transverse and longitudinal anisotropy, wherein the iron loss P 1.5 / 50 Anisotropy ≤12%, magnetic induction B 50 Anisotropy ≤1.5%, mechanical yield strength Rp0.2 anisotropy ≤3.0%, tensile strength Rm anisotropy ≤2.0%.

[0087] Other parts not described belong to the prior art.

Claims

1. A low anisotropic non-oriented silicon steel, characterized in that: The invention comprises the following chemical components in percentage by weight: Si 0.25% to 3.5%, Mn 0.15% to 0.55%, Als 0.10% to 1.15%.

2. The non-oriented silicon steel according to claim 1, characterized in that: It includes the following chemical components in weight percentage: C≤0.0035%, Si 0.25%~3.5%, Mn 0.15%~0.55%, Als0.10%~1.15%, P≤0.1%, S≤0.01%, N≤0.02%, Ti≤0.02%, O≤0.0070%, and the rest are Fe and unavoidable impurities.

3. A method for producing non-oriented silicon steel according to claim 1 or 2, characterized in that: include: Continuous casting, hot rolling, pickling, cold rolling, annealing; the hot rolling includes heating, rolling and coiling.

4. The production method according to claim 3, characterized in that: During the continuous casting process, molten steel is cast into a slab with a thickness of 150 to 250 mm; after continuous casting, the slab enters the heating process, the heating temperature is 1000 to 1180° C., and the soaking time is 120 to 210 minutes.

5. The production method according to claim 3, characterized in that: During the rolling process, the ingot is roughly rolled to a thickness of 28 mm to 40 mm and then fine rolled; the final rolling temperature is 810 to 920° C. The thickness of the hot-rolled plate after fine rolling is controlled according to the following formula: Among them, d 热 is the thickness of hot rolled plate, d 成 is the finished steel thickness.

6. The production method according to claim 3, characterized in that: During the coiling process, the coiling temperature is 560-710°C.

7. The production method according to claim 3, characterized in that: Also includes: When Σ wt When (Si+Al)>2.0%, the hot rolled coil is normalized and then pickled, the normalizing temperature is 800-1000°C, and the normalizing time is 2-5min; wherein Si and Al represent the weight percentage of the corresponding chemical elements in the steel product.

8. The production method according to claim 3, characterized in that: The cold rolling process adopts a one-time cold rolling process to cold roll the pickled hot-rolled plate to the thickness of finished steel; the thickness of the finished steel is 0.25-0.65mm, and the total cold rolling reduction rate is 50%-80%.

9. The production method according to claim 3, characterized in that: The annealing process is carried out in an annealing furnace, the process section running speed is 100-150m / min, the protective atmosphere in the furnace is a nitrogen-hydrogen mixed gas, the dew point in the furnace is controlled below -10°C, and the tension in the furnace is 1.0-2.0KN.

10. The production method according to any one of claims 3 to 9, characterized in that: During the annealing process, the cold-rolled sheet is heated to 730-900°C and kept at this temperature for 29-44 seconds, and then continued to be heated to the aquifer temperature and kept at this temperature for 10-30 seconds; the aquifer temperature T 均 The temperature is 830-990℃ and controlled according to the following formula: T 均 (℃)≤-59954.88×[Σ wt (Yes+Al)] 2 +8061.347×[Σ wt (Si+Al)]+813.12, Among them, Si and Al represent the weight percentage of the corresponding chemical elements in the steel products.

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