Method for manufacturing low iron loss high strength non-oriented silicon steel adaptable to different temperatures

Abstract

The present invention provides a method for manufacturing low iron loss and high strength non-oriented silicon steel that can adapt to different temperatures. The hot rolling process adopts a hot charging method to perform heating and hot rolling. The heating temperature of the ingot is below 1150°C, and the ingot temperature is maintained above 1100°C for not less than 50 minutes. The total duration of the ingot heating process does not exceed 200 minutes. In the annealing process, radiation tube heating is first used to reach the high temperature section annealing temperature within 50 seconds and maintained for 45 to 60 seconds. Then, resistance heating is used to control the annealing temperature at the process section T 工艺 Maintain for 30~50s; before reaching the high temperature section annealing temperature, ensure that the strip temperature is quickly heated to above 900℃ within 20s; the high temperature section annealing temperature T 高温 Need to meet T 高温 ≥T 工艺 +20℃. The present invention obtains a high-grade non-oriented silicon steel suitable for operation in a variable temperature environment through reasonable composition and process control. 1.5 / 50 ≤2.45W / kg, B 50 ≥1.65T, yield strength ≥350MPa, tensile strength ≥500Mpa, especially suitable for rotating motors.

Description

Technical Field

[0001] The present invention relates to the technical field of non-oriented silicon steel, in particular to a method for manufacturing low iron loss and high strength non-oriented silicon steel that is adaptable to different temperatures. Background Art

[0002] Silicon steel sheets are the most common and important magnetic material used in motor cores, ensuring high efficiency and power density. In particular, the magnetic properties of the non-oriented silicon steel sheets used in motor stators determine the motor's torque and efficiency, while their mechanical properties determine the machining accuracy, service load-bearing strength, and maximum speed of the stator and rotor. However, the actual operating environment of motors is highly variable, with operating temperatures varying significantly between cold and hot regions. This requires silicon steel to have relatively stable magnetic properties at varying operating temperatures to avoid significantly impacting motor performance.

[0003] In response to the requirements of silicon steel materials at different ambient temperatures, the Chinese invention application with publication number CN117363861A provides a non-oriented silicon steel with excellent electromagnetic properties in high temperature environments and a manufacturing method thereof, which can achieve P 1.0 / 1000 =46~50W / kg, magnetic induction B 50 It can reach 1.67~1.68T. This solution improves the performance of the product in high-temperature working environments and has no direct impact on the magnetic and mechanical properties in low-temperature environments. The Chinese invention application with publication number CN119614992A provides a non-oriented silicon steel with excellent comprehensive performance and a manufacturing method thereof. By optimizing the chemical composition design and process design of the steel, a reasonable control range of the thermal conductivity and resistivity of the non-oriented silicon steel is set to obtain a non-oriented silicon steel sheet with excellent comprehensive performance that takes into account both thermal conductivity and electromagnetic properties. The thermal conductivity λ of the final finished non-oriented silicon steel sheet at 150°C is 150 The resistivity at room temperature is 10~35W / mK, and the resistivity ρ is 40~90μΩ·cm, and satisfies: 1000≤λ 150 ×ρ≤2000, and at the same time has good electromagnetic properties, the finished steel plate iron loss P 10 / 700 ≤50W / kg. The temperature rise of the permanent magnet synchronous motors produced using these embodiments is lower than the target value of 125°C. This solution mainly studies thermal conductivity and does not involve electromagnetic performance at different temperatures. Summary of the Invention

[0004] To overcome the shortcomings of the above-mentioned technologies, the present invention aims to provide a method for manufacturing low-iron-loss, high-strength non-oriented silicon steel that is adaptable to different temperatures. By rationally controlling the composition and process, a high-grade non-oriented silicon steel having a Si content of 2.8-3.5% and an Als content of 0.5-1.0% is obtained for use in rotating electrical machines suitable for operation in variable temperature environments, and a method for manufacturing the same is provided, thereby solving the problem of significant performance variations of silicon steel materials at different operating temperatures.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A method for manufacturing low iron loss and high strength non-oriented silicon steel that can adapt to different temperatures is special in that it includes the following steps: molten iron pretreatment, converter smelting, RH refining, casting, hot rolling, normalizing treatment, primary cold rolling, annealing, and insulating coating; the hot rolling process adopts a hot charging method for heating and hot rolling, the heating temperature of the ingot is below 1150°C, and the ingot temperature is maintained above 1100°C for not less than 50 minutes, and the total duration of the ingot heating process does not exceed 200 minutes; in the annealing process, radiation tube heating is first used to reach the high-temperature section annealing temperature within 50 seconds and maintained for 45 to 60 seconds, and then resistance heating is used to control the annealing temperature in the process section and maintained for 30 to 50 seconds; before reaching the high-temperature section annealing temperature, it is ensured that the strip temperature is quickly heated to above 900°C within 20 seconds; the high-temperature section annealing temperature must meet T 高温 ≥T 工艺 +20℃, the annealing temperature in the process section is 930~980℃, among which, T 高温 is the high temperature annealing temperature, T 工艺 is the annealing temperature of the process section.

[0007] In order to control the dissolution of fine inclusions at high temperature and subsequent precipitation at low temperature, the total heating time before hot rolling should not be too long, generally not exceeding 200 minutes; in order to ensure uniform temperature throughout the billet and avoid stress concentration or uneven deformation caused by temperature gradients, it is necessary to maintain high temperature for a certain period of time.

[0008] Annealing process includes rapid heating section, high temperature section, process section, T 高温 Refers to the annealing temperature in the high temperature section, T 工艺This refers to the annealing temperature during the process. Rapid heating to a certain temperature quickly provides sufficient energy to alter the material's internal crystal structure. This shortens the nucleation incubation period, rapidly raising the temperature above the surface texture nucleation temperature, and shortening the nucleation time difference between surface texture nuclei and other nuclei, enabling rapid growth at high temperatures. Radiant tube heating offers inferior uniformity and stability compared to resistance heating, so resistance heating is employed during the process to achieve more uniform microstructure in the strip. This heating method makes it easier to achieve favorable textures, reduce unfavorable textures, and achieve optimal grain size control.

[0009] As a preferred solution, the thickness of the ingot obtained after the casting is 150-250 mm; during the normalizing process, the normalizing temperature is 800-900°C.

[0010] As a preferred embodiment, during the normalizing process, when 3.0%≤(Si+Als)<4.0%, the normalizing temperature is 850~900℃; when 4.0%≤(Si+Als)≤5.0%, the normalizing temperature is 800~850℃, and Sn element is added during molten iron smelting so that the non-oriented silicon steel product contains Sn element; wherein Si and Als refer to the weight percentage of the corresponding elements in the non-oriented silicon steel product.

[0011] As a preferred solution, during the converter smelting process, the slag basicity CaO / SiO2 in the steel slag is controlled to be ≤3.2.

[0012] As a preferred embodiment, during the hot rolling process, the heated slab is rough-rolled for 5 or 3 passes and then finish-rolled to 1.8-2.5 mm on 7 stands; the intermediate slab thickness is 35-45 mm, the rough-rolling outlet temperature is ≥980°C, the finishing rolling temperature is 840-900°C, and the coiling temperature is 550-690°C, thereby laying a good organizational foundation for subsequent grain growth and texture inheritance.

[0013] As a preferred solution, after the normalizing treatment, the steel strip is cooled sequentially using water jacket cooling, air-mist cooling, and water spray cooling; the air-mist cooling cools the steel strip from the process temperature to 500°C; the water spray cooling cools the steel strip from 500°C to below 80°C; and a blower is used between the water jacket cooling and air-mist cooling sections to spray air onto the upper and lower surfaces of the steel strip. To ensure uniform microstructure after normalizing, the cooling process after normalizing first uses water jacket cooling, where cooling water circulates between the two furnace shells, absorbing radiant heat from the high-temperature steel strip from the soaking furnace and slowly cooling the steel strip. Then, air-mist cooling is used to cool the steel strip from the process temperature to 500°C, where cooling water is atomized into tiny droplets under the action of compressed air and evenly sprayed onto the strip surface through an air mist cooling nozzle, evenly and quickly removing heat from the strip and achieving the purpose of rapidly cooling the strip. Finally, the water spray cooling section cools the steel strip from 500°C to below 80°C. A blower is used between the water jacket cooling and the air-mist cooling section to spray air through a nozzle onto the upper and lower surfaces of the strip. This can prevent water in the water spray cooling section from flowing back into the soaking furnace and the outlet sealing chamber, and can also adjust the strip temperature before the water spray cooling section.

[0014] As a preferred solution, during the primary cold rolling process, the slab is rolled to a thickness of 0.25 to 0.35 mm.

[0015] As a preferred solution, during the annealing process, the annealing temperature of the process section is 930~980℃, the atmosphere is a nitrogen-hydrogen mixed atmosphere, the dew point is below -10℃, and the required recrystallized structure is obtained. During the annealing process, the unit tension in the furnace is ≤2.5N / mm 2 .

[0016] Furthermore, in the nitrogen-hydrogen mixed atmosphere, the volume ratio of N2 to H2 is 7:3.

[0017] Furthermore, as a preferred solution, after the insulating coating is applied, it is dried and cured at a temperature below 500° C. to obtain excellent insulating properties.

[0018] As a preferred solution, the non-oriented silicon steel is used to prepare a rotating electrical machine.

[0019] As a preferred embodiment, the non-oriented silicon steel comprises the following chemical components in weight percentage: Si: 2.8-3.5%, Mn: 0.25-0.65%, Als: 0.5-1.0%, and 3.5%≤(Si+Als)≤4.3%, where Si and Als refer to the weight percentages of the corresponding elements in the non-oriented silicon steel product.

[0020] As a preferred solution, the non-oriented silicon steel further comprises: when 4.0%≤(Si+Als), adding 0.02%≤Sn≤0.10%.

[0021] Furthermore, the non-oriented silicon steel further comprises the following chemical components in percentage by weight: C≤0.0020%, S≤0.0015%, N≤0.0015%, Ti≤0.0020%, and the remainder is Fe and unavoidable impurities.

[0022] As a preferred solution, the non-oriented silicon steel is in the range of -40℃~200℃: P 1.5 / 50 ≤2.45W / kg, B 50 ≥1.65T, yield strength ≥350MPa, tensile strength ≥500Mpa.

[0023] The role of each element in the steel of the present invention is as follows:

[0024] Si: Si increases resistance and is the most important alloying element in electrical steel. To achieve low iron loss, especially at high frequencies, the Si content needs to be increased, requiring a Si content of ≥2.5%. However, an increase in Si reduces magnetic induction. Excessive Si content also affects cold rolling and increases manufacturing difficulty. Therefore, the Si content needs to be controlled at ≤3.5%.

[0025] Mn: Manganese and sulfur form MnS, which can prevent the hot brittleness caused by the formation of low-melting-point FeS along the grain boundaries. Therefore, a certain amount of manganese must be ensured to improve hot-rolled plasticity.

[0026] Al: Aluminum has a similar effect to silicon, increasing the ρ value, reducing the γ region and promoting grain growth, reducing iron loss while also reducing magnetic permeability.

[0027] Sn: Increasing the Si or Al content in the alloy, or reducing the thickness, significantly affects the magnetic induction. Adding Sn ensures magnetic induction while reducing iron loss. Especially when (Si + Als) ≥ 4.0%, Sn (0.02% ≤ Sn ≤ 0.10%) is necessary to compensate for the magnetic induction loss caused by low-temperature normalization. Sn suppresses the unfavorable {111} texture by grain boundary segregation.

[0028] The present invention emphasizes the coordinated control of Si / Al: Si is limited to 2.8-3.5%, Als is 0.5-1.0%, and 3.5%≤(Si+Als)≤4.3% is required, balancing magnetic properties and strength through solid solution strengthening.

[0029] N: It easily forms fine AlN particles with Al to inhibit grain growth. When N>0.0025%, the iron loss increases significantly.

[0030] S: In addition to combining with Mn to form MnS, S also forms fine Cu2S precipitates with a small amount of Cu. The size of Cu2S is generally small, ranging from 30 to 200 nm.

[0031] Ti: Ti will form small-sized TiN, TiC and Ti(CN) with C and N, with different sizes below 100nm. Generally, Ti is required to be ≤ 0.0020%.

[0032] N: Interstitial atoms in non-oriented silicon steel will precipitate Fe3C and Fe4N at 100~300℃, which are difficult to coarsen and exist in a dispersed form, deteriorating the magnetic properties. Therefore, the C and N contents should be as low as possible.

[0033] Ultra-low impurity control: C≤0.0020%, S≤0.0015%, N≤0.0015%, Ti≤0.0020%, significantly reducing the pinning effect of relative magnetic domain movement.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention obtains a low iron loss, high strength, high grade non-oriented silicon steel with Si content between 2.8-3.5% and Als content between 0.5-1.0% under a suitable variable temperature environment through reasonable composition and process control. 1.5 / 50 ≤2.45W / kg, B 50 ≥1.65T, yield strength ≥350MPa, tensile strength ≥500Mpa, especially suitable for rotating motors. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the microstructure morphology of the normalized plate in Example 2;

[0037] Figure 2 This is the microstructure morphology of the normalized plate in Comparative Example 2. DETAILED DESCRIPTION

[0038] In order to better explain the present invention, the main contents of the present invention are further illustrated below with reference to the accompanying drawings and specific embodiments, but the contents of the present invention are not limited to the following embodiments.

[0039] The present invention provides a low iron loss, high-strength non-oriented silicon steel suitable for different temperatures, whose chemical composition and weight percentage are as follows: C≤0.0020%, Si: 2.8-3.5%, Mn: 0.25-0.65%, 0.5%≤Als≤1.0%, S≤0.0015%, N≤0.0015%, Ti≤0.0020%, Sn≤0.10%, and 3.5%≤(Si+Als)≤4.3%, with the remainder being Fe and unavoidable impurities; and when 4.0%≤(Si+Als)≤4.3%, 0.02%≤Sn≤0.10%.

[0040] The manufacturing method of the above-mentioned non-oriented silicon steel is as follows:

[0041] 1) The raw molten iron is pretreated with two desulfurization treatments and three slag removals to ensure that the amount of slag in the molten iron is as small as possible.

[0042] 2) The molten iron is smelted in a converter, and the CaO / SiO2 ratio of the converter slag is controlled to be ≤3.2.

[0043] 3) The molten steel is vacuum treated in an RH refining furnace and alloys are added to obtain the required alloy composition.

[0044] 4) The molten steel with the above composition is cast into 150~250mm ingots under protective casting.

[0045] 5) The ingot is heated and hot rolled by hot charging. The heating temperature of the ingot is controlled below 1150℃, but the time when the temperature is above 1100℃ needs to be controlled for more than 50 minutes. In order to control the dissolution of fine inclusions at high temperature and subsequent precipitation at low temperature, the total heating time should not be too long, generally not exceeding 200 minutes.

[0046] 6) The heated slab undergoes 5 or 3 rough rolling passes and then 7-stand finish rolling to a thickness of 1.8-2.5 mm. The intermediate slab thickness is 35-45 mm. The rough rolling exit temperature is ≥ 980°C, the finishing rolling temperature is 840-900°C, and the coiling temperature is 550-690°C. This lays a good microstructure foundation for subsequent grain growth and texture inheritance.

[0047] 7) After normalizing at 800-900°C, the hot-rolled plate obtained has a uniform equiaxed grain structure of 35-90 μm.

[0048] To ensure uniform microstructure after normalizing, water jacket cooling is first employed after normalizing. This involves circulating cooling water between the two furnace shells, absorbing radiant heat from the high-temperature strip from the soaking furnace and slowly cooling the strip. Gas-mist cooling is then used to cool the strip from the process temperature to 500°C. This involves atomizing the cooling water into tiny droplets under the action of compressed air. These droplets are then evenly sprayed onto the strip surface through gas-mist cooling nozzles, evenly and quickly removing heat from the strip and achieving rapid cooling. Finally, a water-spray cooling section cools the strip from 500°C to below 80°C. Between the water-jacket cooling and gas-mist cooling sections, a blower sprays air through nozzles onto the upper and lower surfaces of the strip. This prevents water from the water-spray cooling section from flowing back into the soaking furnace and the exit sealed chamber, and also allows for adjustment of the strip temperature before the water-spray cooling section.

[0049] Due to the high content of Si and Al, the brittleness of the material increases. In order to reduce the risk of band breakage during cold working, the normalizing process is optimized to ensure that the grain size after normalizing is in an appropriate range. The relationship between the normalizing temperature and the Si + Als content must meet the following requirements: 3.0% ≤ (Si + Als) < 4.0%, the normalizing temperature is between 850 and 900 ° C, 4.0% ≤ (Si + Als) ≤ 5.0%, the normalizing temperature is between 800 and 850 ° C. At the same time, a certain amount of Sn element is added. Because the normalizing temperature is low, the magnetic induction will be low. At this time, the proportion of favorable texture is increased by adding Sn elements, thereby ensuring that the magnetic induction meets the requirements.

[0050] 8) After normalizing treatment, the strip steel is cold rolled to 0.25~0.35mm in one step;

[0051] 9) Anneal the cold-rolled strip at a process temperature of 930-980°C in a nitrogen-hydrogen mixed atmosphere (N2:H2=7:3) with a dew point below -10°C to obtain the required recrystallized structure. During the annealing process, the unit tension in the furnace is ≤2.5N / mm. 2 Then, an insulating coating is applied to the surface of the steel strip and dried and solidified at a temperature below 500°C to obtain excellent insulation performance.

[0052] The annealing process is preferably heated by radiation tubes. The strip temperature is quickly heated to above 900℃ within 20s, reaches the high temperature annealing temperature within 50s and is maintained for 45~60s. Then, it is switched to resistance heating and maintained for 30~50s after the strip reaches the process section temperature. The process section temperature is 930~980℃. To ensure the formation of favorable texture, T 高温 ≥T 工艺 +20℃, T 高温 is the high temperature annealing temperature, T 工艺 is the annealing temperature of the process section.

[0053] The present invention is further described below by Examples 1 to 6 and Comparative Examples 1 to 4.

[0054] Examples 1-6 employ the chemical compositions and manufacturing methods of the present invention. Comparative Examples 1-4 differ from the examples in chemical composition and process parameters. The chemical compositions and weight percentages of the non-oriented silicon steel products in Examples 1-6 and Comparative Examples 1-4 are shown in Table 1, and the product performance results are shown in Tables 2 and 3.

[0055] Table 1: Chemical composition of non-oriented silicon steel in Examples and Comparative Examples, the remainder being Fe and unavoidable impurities, weight percentage / %

[0056] Serial number C Si Mn S Als N Ti Sn Example 1 0.0016 2.8 0.30 0.0014 0.7 0.0010 0.0014 / Example 2 0.0015 3.0 0.25 0.0010 0.5 0.0012 0.0010 / Example 3 0.0018 3.25 0.40 0.0008 0.85 0.0013 0.0017 0.02 Example 4 0.0020 3.45 0.55 0.0012 0.65 0.0011 0.0012 0.05 Example 5 0.0017 3.35 0.5 0.0010 0.90 0.0014 0.0016 0.08 Example 6 0.0016 3.40 0.6 0.0013 0.75 0.0012 0.0019 0.10 Comparative Example 1 0.0019 2.8 0.30 0.0014 0.7 0.0010 0.0014 / Comparative Example 2 0.0015 3.0 0.25 0.0010 0.5 0.0012 0.0010 / Comparative Example 3 0.0020 3.65 0.20 0.0025 0.95 0.0014 0.0016 / Comparative Example 4 0.0020 2.45 0.20 0.0025 1.05 0.0014 0.0016 /

[0057] Example 1

[0058] A method for manufacturing low iron loss and high strength non-oriented silicon steel suitable for different temperatures, wherein the chemical composition and weight percentage of the non-oriented silicon steel are shown in Example 1 in Table 1. The manufacturing method comprises the following steps:

[0059] 1) Pre-treat the raw molten iron, perform two desulfurization treatments, and three slag removals to ensure that the amount of slag is as small as possible;

[0060] 2) Smelting the molten iron in a converter, controlling the CaO / SiO2 ratio of the converter steel to be 2.8;

[0061] 3) The molten steel is vacuum treated in an RH refining furnace and alloys are added to obtain the required alloy composition;

[0062] 4) Casting the molten steel into 230mm ingots under protective casting;

[0063] 5) The slab is heated and hot rolled by hot charging. The heating temperature of the slab is controlled at 1150°C. The total heating time is 150 minutes, and the time when the temperature is above 1100°C is 55 minutes.

[0064] 6) The heated slab undergoes three rough rolling passes and then finish rolling to 2.5mm on seven stands. The intermediate slab thickness is 45mm, the rough rolling outlet temperature is 1000°C, the finishing rolling temperature is 880°C, and the coiling temperature is 690°C.

[0065] 7) After normalizing at 880°C, the hot-rolled plate obtained obtained a uniform equiaxed grain structure of 77 μm;

[0066] 8) After normalizing, the strip is cooled sequentially through water jacket cooling, air-mist cooling, and water spray cooling, and then cold rolled to 0.35mm in one step. The water jacket cooling slowly cools the strip, and the air-mist cooling cools the strip from the process temperature to 500°C. The water spray cooling cools the strip from 500°C to below 80°C. Between the water jacket cooling and air-mist cooling sections, a blower is used to spray air onto the upper and lower surfaces of the strip.

[0067] 9) After cold rolling, the strip is preferentially heated using radiation tubes. The strip temperature is rapidly heated to 900°C in 12 seconds, reaching 980°C in 35 seconds and maintaining this temperature for 45 seconds. Resistance heating is then used and the strip temperature is maintained at 950°C for 45 seconds. The annealing atmosphere is a nitrogen-hydrogen mixture (N2:H2=7:3) with a dew point of -20°C. The unit tension in the furnace is 2.0N / mm during the annealing process. 2 Then, an insulating coating is applied to the surface of the strip and dried and cured at a temperature below 500°C to obtain excellent insulation properties.

[0068] Example 2

[0069] A method for manufacturing low iron loss and high strength non-oriented silicon steel suitable for different temperatures, wherein the chemical composition and weight percentage of the non-oriented silicon steel are shown in Example 2 in Table 1. The manufacturing method comprises the following steps:

[0070] 1) Pre-treat the raw molten iron, perform two desulfurization treatments, and three slag removals to ensure that the amount of slag is as small as possible;

[0071] 2) smelting the molten iron in a converter, controlling the CaO / SiO2 ratio of the converter steel to be 2.0;

[0072] 3) The molten steel is vacuum treated in an RH refining furnace and alloys are added to obtain the required alloy composition;

[0073] 4) Casting the molten steel into 200mm ingots under protective casting;

[0074] 5) The slab is heated and hot rolled by hot charging. The heating temperature of the slab is controlled at 1120°C. The total heating time is 185 minutes, and the time when the temperature is above 1100°C is 53 minutes.

[0075] 6) The heated slab is rough rolled three times and then finished rolled to 2.3mm on seven stands. The intermediate slab thickness is 40mm, the rough rolling outlet temperature is 985°C, the finishing rolling temperature is 860°C, and the coiling temperature is 650°C.

[0076] 7) After normalizing at 900°C, the hot-rolled plate obtained has a uniform equiaxed grain structure of 65 μm;

[0077] 8) After normalizing, the strip is cooled in sequence through water jacket cooling, air-mist cooling, and water spray cooling, and then cold rolled to 0.30mm in one step. The water jacket cooling slowly cools the strip, and the air-mist cooling cools the strip from the process temperature to 500℃. The water spray cooling cools the strip from 500℃ to below 80℃. Between the water jacket cooling and air-mist cooling sections, a blower is used to spray air onto the upper and lower surfaces of the strip.

[0078] 9) After cold rolling, the strip is preferentially heated using radiation tubes. The strip temperature is rapidly heated to 900°C in 18 seconds, reaching 970°C in 45 seconds and maintaining this temperature for 50 seconds. Resistance heating is then used and the strip temperature is maintained at 950°C in the process section for 35 seconds. The annealing atmosphere is a nitrogen-hydrogen mixture (N2:H2=7:3) with a dew point of -30°C. The unit tension in the furnace is 2.2N / mm during the annealing process. 2 Then, an insulating coating is applied to the surface of the strip and dried and cured at a temperature below 500°C to obtain excellent insulation properties.

[0079] The morphology of the normalized plate in this embodiment is shown in FIG. Figure 1As shown in the figure, it can be seen that the structure of the normalized plate in this embodiment is uniform and the grains are equiaxed, which shows that the normalizing treatment is sufficient and effective and good comprehensive performance can be obtained.

[0080] Example 3

[0081] A method for manufacturing low iron loss and high strength non-oriented silicon steel suitable for different temperatures, wherein the chemical composition and weight percentage of the non-oriented silicon steel are shown in Example 3 in Table 1. The manufacturing method comprises the following steps:

[0082] 1) Pre-treat the raw molten iron, perform two desulfurization treatments, and three slag removals to ensure that the amount of slag is as small as possible;

[0083] 2) Smelting the molten iron in a converter, controlling the CaO / SiO2 ratio of the converter steel to be 2.8;

[0084] 3) The molten steel is vacuum treated in an RH refining furnace and alloys are added to obtain the required alloy composition;

[0085] 4) Casting the molten steel into 180mm ingots under protective casting;

[0086] 5) The slab is heated and hot rolled by hot charging. The heating temperature of the slab is controlled at 1110°C. The total heating time is 190 minutes, and the temperature is above 1100°C for 69 minutes.

[0087] 6) The heated slab undergoes three rough rolling passes and then finish rolling on seven stands to a thickness of 2.15 mm. The intermediate slab thickness is 35 mm, the rough rolling outlet temperature is 985°C, the finishing rolling temperature is 850°C, and the coiling temperature is 680°C.

[0088] 7) After normalizing at 850°C, the hot-rolled plate obtained has a uniform equiaxed grain structure of 65 μm;

[0089] 8) After normalizing, the strip is cooled sequentially through water jacket cooling, air-mist cooling, and water spray cooling, and then cold rolled to 0.27mm. The water jacket cooling slowly cools the strip, and the air-mist cooling cools the strip from the process temperature to 500°C. The water spray cooling cools the strip from 500°C to below 80°C. Between the water jacket cooling and air-mist cooling sections, a blower is used to spray air onto the upper and lower surfaces of the strip.

[0090] 9) After cold rolling, the strip is heated using radiation tubes. The strip temperature is rapidly heated to 900°C in 15 seconds, reaching 980°C in 40 seconds and maintaining this temperature for 45 seconds. Then, resistance heating is used and the strip temperature is maintained at 950°C in the process section for 30 seconds. At the same time, the annealing atmosphere is ensured to be a nitrogen-hydrogen mixture (N2:H2=7:3) with a dew point of -20°C. The unit tension in the furnace during annealing is 2.5N / mm. 2Then, an insulating coating is applied to the surface of the strip and dried and cured at a temperature below 500°C to obtain excellent insulation properties.

[0091] Example 4

[0092] A method for manufacturing low iron loss and high strength non-oriented silicon steel suitable for different temperatures, wherein the chemical composition and weight percentage of the non-oriented silicon steel are shown in Example 4 in Table 1. The manufacturing method comprises the following steps:

[0093] 1) Pre-treat the raw molten iron, perform two desulfurization treatments, and three slag removals to ensure that the amount of slag is as small as possible;

[0094] 2) smelting the molten iron in a converter, controlling the CaO / SiO2 ratio of the converter steel to be 2.5;

[0095] 3) The molten steel is vacuum treated in an RH refining furnace and alloys are added to obtain the required alloy composition;

[0096] 4) Casting the molten steel into 200mm ingots under protective casting;

[0097] 5) The slab is heated and hot rolled by hot charging. The heating temperature of the slab is controlled at 1110°C. The total heating time is 190 minutes, and the temperature is above 1100°C for 60 minutes.

[0098] 6) The heated slab undergoes three rough rolling passes and then finish rolling to 2.0 mm on seven stands. The intermediate slab thickness is 38 mm, the rough rolling outlet temperature is 985°C, the finishing rolling temperature is 840°C, and the coiling temperature is 650°C.

[0099] 7) After normalizing at 830°C, the hot-rolled plate obtained obtained a uniform equiaxed grain structure of 48 μm;

[0100] 8) After normalizing, the strip is cooled in sequence through water jacket cooling, air-mist cooling, and water spray cooling, and then cold rolled to 0.25mm. The water jacket cooling slowly cools the strip, and the air-mist cooling cools the strip from the process temperature to 500°C. The water spray cooling cools the strip from 500°C to below 80°C. Between the water jacket cooling and air-mist cooling sections, a blower is used to spray air onto the upper and lower surfaces of the strip.

[0101] 9) After cold rolling, the strip is preferentially heated using radiation tubes. The strip temperature is rapidly heated to above 900°C in 13 seconds, reaching 960°C in 38 seconds and maintaining this temperature for 48 seconds. Resistance heating is then used and the strip temperature is maintained at 935°C in the process section for 35 seconds. The annealing atmosphere is maintained to be a nitrogen-hydrogen mixture (N2:H2=7:3) with a dew point of -30°C. The unit tension in the furnace is 2.5N / mm during the annealing process. 2Then, an insulating coating is applied to the surface of the strip and dried and cured at a temperature below 500°C to obtain excellent insulation properties.

[0102] Example 5

[0103] A method for manufacturing low iron loss and high strength non-oriented silicon steel suitable for different temperatures, wherein the chemical composition and weight percentage of the non-oriented silicon steel are shown in Example 5 in Table 1. The manufacturing method comprises the following steps:

[0104] 1) Pre-treat the raw molten iron, perform two desulfurization treatments, and three slag removals to ensure that the amount of slag is as small as possible;

[0105] 2) Smelting the molten iron in a converter, controlling the CaO / SiO2 ratio of the converter steel to be 2.8;

[0106] 3) The molten steel is vacuum treated in an RH refining furnace and alloys are added to obtain the required alloy composition;

[0107] 4) Casting the molten steel into 230mm ingots under protective casting;

[0108] 5) The slab is heated and hot rolled by hot charging. The heating temperature of the slab is controlled at 1110°C. The total heating time is 195 minutes, and the temperature is above 1100°C for 66 minutes.

[0109] 6) The heated slab undergoes three rough rolling passes and then finish rolling to 2.0 mm on seven stands. The intermediate slab thickness is 38 mm, the rough rolling outlet temperature is 985°C, the finishing rolling temperature is 840°C, and the coiling temperature is 650°C.

[0110] 7) After normalizing at 840°C, the hot-rolled plate obtained has a uniform equiaxed grain structure of 45 μm;

[0111] 8) After normalizing, the strip is cooled in sequence through water jacket cooling, air-mist cooling, and water spray cooling, and then cold rolled to 0.25mm. The water jacket cooling slowly cools the strip, and the air-mist cooling cools the strip from the process temperature to 500°C. The water spray cooling cools the strip from 500°C to below 80°C. Between the water jacket cooling and air-mist cooling sections, a blower is used to spray air onto the upper and lower surfaces of the strip.

[0112] 9) After cold rolling, the strip is heated using radiation tubes. The strip temperature is rapidly heated to 900°C in 15 seconds, reaching 965°C in 35 seconds and maintaining this temperature for 50 seconds. Then, resistance heating is used and the strip temperature is maintained at 940°C in the process section for 30 seconds. At the same time, the annealing atmosphere is ensured to be a nitrogen-hydrogen mixture (N2:H2=7:3) with a dew point of -30°C. The unit tension in the furnace during annealing is 2.5N / mm. 2Then, an insulating coating is applied to the surface of the strip and dried and cured at a temperature below 500°C to obtain excellent insulation properties.

[0113] Example 6

[0114] A method for manufacturing low iron loss and high strength non-oriented silicon steel suitable for different temperatures, wherein the chemical composition and weight percentage of the non-oriented silicon steel are shown in Example 6 in Table 1. The manufacturing method comprises the following steps:

[0115] 1) Pre-treat the raw molten iron, perform two desulfurization treatments, and three slag removals to ensure that the amount of slag is as small as possible;

[0116] 2) smelting the molten iron in a converter, controlling the CaO / SiO2 ratio of the converter steel to be 3.0;

[0117] 3) The molten steel is vacuum treated in an RH refining furnace and alloys are added to obtain the required alloy composition;

[0118] 4) Casting the molten steel into 230mm ingots under protective casting;

[0119] 5) The slab is heated and hot rolled by hot charging. The heating temperature of the slab is controlled at 1120°C. The total heating time is 180 minutes, and the temperature is above 1100°C for 70 minutes.

[0120] 6) The heated slab is rough rolled three times and then finished rolled to 1.8mm on seven stands. The intermediate slab thickness is 35mm, the rough rolling outlet temperature is 990°C, the finishing rolling temperature is 860°C, and the coiling temperature is 690°C.

[0121] 7) After normalizing at 820°C, the hot-rolled plate obtained obtained a uniform equiaxed grain structure of 38 μm;

[0122] 8) After normalizing, the strip is cooled in sequence through water jacket cooling, air-mist cooling, and water spray cooling, and then cold rolled to 0.25mm. The water jacket cooling slowly cools the strip, and the air-mist cooling cools the strip from the process temperature to 500°C. The water spray cooling cools the strip from 500°C to below 80°C. Between the water jacket cooling and air-mist cooling sections, a blower is used to spray air onto the upper and lower surfaces of the strip.

[0123] 9) After cold rolling, the strip is preferentially heated using radiation tubes. The strip temperature is rapidly heated to 900°C in 15 seconds, reaching 1000°C in 50 seconds and maintaining this temperature for 48 seconds. Resistance heating is then used and the strip temperature reaches 980°C in the process section and maintained at this temperature for 40 seconds. The annealing atmosphere is maintained to be a nitrogen-hydrogen mixture (N2:H2=7:3) with a dew point of -30°C. The unit tension in the furnace is 2.5N / mm during the annealing process. 2Then, an insulating coating is applied to the surface of the strip and dried and cured at a temperature below 500°C to obtain excellent insulation properties.

[0124] Comparative Example 1:

[0125] A non-oriented silicon steel for a rotating electrical machine and a method for manufacturing the same, the chemical composition and weight percentages of which are shown in Table 1. The manufacturing method differs from Example 1 in that the heating temperature, heating time, and normalizing temperature do not meet the requirements of the present invention. The properties of the obtained product are shown in Tables 2 and 3. The specific manufacturing method includes the following steps:

[0126] 1) Pre-treat the raw molten iron, perform two desulfurization treatments, and three slag removals to ensure that the amount of slag is as small as possible;

[0127] 2) smelting the molten iron in a converter, controlling the CaO / SiO2 ratio of the converter steel to be 2.5;

[0128] 3) subjecting the molten steel to vacuum treatment in an RH refining furnace and adding alloys;

[0129] 4) The molten steel is cast into 200mm ingots under protective casting;

[0130] 5) The slab is heated and hot rolled by hot charging. The heating temperature of the slab is controlled at 1200°C. The total heating time is 240 minutes, and the time when the temperature is above 1100°C is 60 minutes.

[0131] 6) The heated slab undergoes three rough rolling passes and then finish rolling to 2.0 mm on seven stands. The intermediate slab thickness is 38 mm, the rough rolling outlet temperature is 985°C, the finishing rolling temperature is 840°C, and the coiling temperature is 650°C.

[0132] 7) After normalizing at 830°C, the hot-rolled plate obtained obtained a uniform equiaxed grain structure of 48 μm;

[0133] 8) After normalizing, the strip is cooled sequentially through water jacket cooling, air-mist cooling, and water spray cooling, and then cold rolled to 0.35mm in one step. The water jacket cooling slowly cools the strip, and the air-mist cooling cools the strip from the process temperature to 500°C. The water spray cooling cools the strip from 500°C to below 80°C. Between the water jacket cooling and air-mist cooling sections, a blower is used to spray air onto the upper and lower surfaces of the strip.

[0134] 9) After cold rolling, the strip is preferentially heated using radiation tubes. The strip temperature is rapidly heated to 900°C in 13 seconds, reaching 960°C in 38 seconds and maintaining this temperature for 48 seconds. Resistance heating is then used, and the strip temperature is maintained at 935°C in the process section for 35 seconds. The annealing atmosphere is a nitrogen-hydrogen mixture (N2:H2=7:3) with a dew point of -30°C. The unit tension in the furnace is 2.5N / mm during the annealing process. 2 Then, an insulating coating is applied to the surface of the strip and dried and cured at a temperature below 500°C to obtain excellent insulation properties.

[0135] Comparative Example 2

[0136] A non-oriented silicon steel for a rotating electrical machine and a manufacturing method thereof, the chemical composition and weight percentage of which are shown in Table 1. The manufacturing method differs from Example 2 in that the normalizing and annealing temperatures are outside the scope of the present invention, the proportion of equiaxed grains in the normalized plate is relatively low, and only the surface layer undergoes recrystallization. The properties of the obtained product are shown in Tables 2 and 3. The specific manufacturing method comprises the following steps:

[0137] 1) Pre-treat the raw molten iron, perform two desulfurization treatments, and three slag removals to ensure that the amount of slag is as small as possible;

[0138] 2) smelting the molten iron in a converter, controlling the CaO / SiO2 ratio of the converter steel to be 2.0;

[0139] 3) subjecting the molten steel to vacuum treatment in an RH refining furnace and adding alloys;

[0140] 4) The molten steel is cast into 200mm ingots under protective casting;

[0141] 5) The slab is heated and hot rolled by hot charging. The heating temperature of the slab is controlled at 1120°C. The total heating time is 185 minutes, and the time when the temperature is above 1100°C is 53 minutes.

[0142] 6) The heated slab is rough rolled three times and then finished rolled to 2.3mm on seven stands. The intermediate slab thickness is 40mm, the rough rolling outlet temperature is 985°C, the finishing rolling temperature is 860°C, and the coiling temperature is 650°C.

[0143] 7) After normalizing at 800°C, the hot-rolled plate obtained has a uniform equiaxed grain structure of 40 μm;

[0144] 8) After normalizing, the strip is cooled in sequence through water jacket cooling, air-mist cooling, and water spray cooling, and then cold rolled to 0.30mm in one step. The water jacket cooling slowly cools the strip, and the air-mist cooling cools the strip from the process temperature to 500℃. The water spray cooling cools the strip from 500℃ to below 80℃. Between the water jacket cooling and air-mist cooling sections, a blower is used to spray air onto the upper and lower surfaces of the strip.

[0145] 9) After cold rolling, the strip is preferentially heated using radiation tubes. The strip temperature is rapidly heated to 900°C in 18 seconds, reaching 970°C in 45 seconds and maintaining this temperature for 50 seconds. Resistance heating is then used and the strip temperature reaches 980°C in the process section and is maintained at this temperature for 35 seconds. The annealing atmosphere is a nitrogen-hydrogen mixture (N2:H2=7:3) with a dew point of -30°C. The unit tension in the furnace is 2.2N / mm during the annealing process. 2 Then, an insulating coating is applied to the surface of the strip and dried and cured at a temperature below 500°C to obtain excellent insulation properties.

[0146] The organizational morphology of the normalized plate in this comparative example is shown in FIG. Figure 2 As shown in the figure, the normalized plate in this comparative example clearly has a banded structure problem. This structure will lead to a decrease in material performance in the thickness direction, especially a decrease in ductility.

[0147] Comparative Example 3

[0148] A non-oriented silicon steel for a rotating electrical machine and a method for manufacturing the same, wherein the chemical composition and weight percentages are shown in Table 1. The chemical composition does not meet the corresponding relationship required by the present invention, and the production method is the same as that of Example 4. The properties of the obtained product are shown in Tables 2 and 3. The specific manufacturing method comprises the following steps:

[0149] 1) Pre-treat the raw molten iron, perform two desulfurization treatments, and three slag removals to ensure that the amount of slag is as small as possible;

[0150] 2) smelting the molten iron in a converter, controlling the CaO / SiO2 ratio of the converter steel to be 2.5;

[0151] 3) subjecting the molten steel to vacuum treatment in an RH refining furnace and adding alloys;

[0152] 4) The molten steel is cast into 200mm ingots under protective casting;

[0153] 5) The slab is heated and hot rolled by hot charging. The heating temperature of the slab is controlled at 1110°C. The total heating time is 190 minutes, and the temperature is above 1100°C for 60 minutes.

[0154] 6) The heated slab undergoes three rough rolling passes and then finish rolling to 2.0 mm on seven stands. The intermediate slab thickness is 38 mm, the rough rolling outlet temperature is 985°C, the finishing rolling temperature is 840°C, and the coiling temperature is 650°C.

[0155] 7) After normalizing at 830°C, the hot-rolled plate obtained obtained a uniform equiaxed grain structure of 48 μm;

[0156] 8) After normalizing, the strip is cooled in sequence through water jacket cooling, air-mist cooling, and water spray cooling, and then cold rolled to 0.25mm. The water jacket cooling slowly cools the strip, and the air-mist cooling cools the strip from the process temperature to 500°C. The water spray cooling cools the strip from 500°C to below 80°C. Between the water jacket cooling and air-mist cooling sections, a blower is used to spray air onto the upper and lower surfaces of the strip.

[0157] 9) After cold rolling, the strip is preferentially heated using radiation tubes. The strip temperature is rapidly heated to 900°C in 13 seconds, reaching 960°C in 38 seconds and maintaining this temperature for 48 seconds. Resistance heating is then used, and the strip temperature is maintained at 935°C in the process section for 35 seconds. The annealing atmosphere is a nitrogen-hydrogen mixture (N2:H2=7:3) with a dew point of -30°C. The unit tension in the furnace is 2.5N / mm during the annealing process. 2 Then, an insulating coating is applied to the surface of the strip and dried and cured at a temperature below 500°C to obtain excellent insulation properties.

[0158] Comparative Example 4

[0159] A non-oriented silicon steel for a rotating electrical machine and a method for manufacturing the same, wherein the chemical composition and weight percentages are shown in Table 1. The annealing process and composition of the non-oriented silicon steel do not meet the corresponding relationship required by the present invention, and the performance of the obtained product is shown in Tables 2 and 3. The specific manufacturing method comprises the following steps:

[0160] 1) Pre-treat the raw molten iron, perform two desulfurization treatments, and three slag removals to ensure that the amount of slag is as small as possible;

[0161] 2) smelting the molten iron in a converter, controlling the CaO / SiO2 ratio of the converter steel to be 2.5;

[0162] 3) subjecting the molten steel to vacuum treatment in an RH refining furnace and adding alloys;

[0163] 4) The molten steel is cast into 200mm ingots under protective casting;

[0164] 5) The slab is heated and hot rolled by hot charging. The heating temperature of the slab is controlled at 1140°C. The total heating time is 170 minutes, and the temperature is above 1100°C for 60 minutes.

[0165] 6) The heated slab undergoes three rough rolling passes and then finish rolling to 2.0 mm on seven stands. The intermediate slab thickness is 38 mm, the rough rolling outlet temperature is 985°C, the finishing rolling temperature is 840°C, and the coiling temperature is 650°C.

[0166] 7) After normalizing at 850°C, the hot-rolled plate obtained obtains a uniform equiaxed grain structure of 50 μm;

[0167] 8) After normalizing, the strip is cooled in sequence through water jacket cooling, air-mist cooling, and water spray cooling, and then cold rolled to 0.25mm. The water jacket cooling slowly cools the strip, and the air-mist cooling cools the strip from the process temperature to 500°C. The water spray cooling cools the strip from 500°C to below 80°C. Between the water jacket cooling and air-mist cooling sections, a blower is used to spray air onto the upper and lower surfaces of the strip.

[0168] 9) After cold rolling, heat the strip using a radiant tube. Slowly heat the strip to 900°C after 30 seconds, and continue heating until it reaches 940°C and maintain this temperature for 100 seconds. Ensure that the annealing atmosphere is a nitrogen-hydrogen mixture (N2:H2=7:3) with a dew point of -30°C. During the annealing process, the unit tension in the furnace is 2.5N / mm. 2 Then, an insulating coating is applied to the surface of the strip and dried and cured at a temperature below 500°C to obtain excellent insulation properties.

[0169] The non-oriented silicon steel obtained by the preparation method in the embodiment and the comparative example was tested for its iron loss P at different temperatures according to the national standard GB / T 3655-2022. 15 / 50 , magnetic induction intensity B 50 According to GB / T228 "Metallic Materials - Tensile Test", the yield strength Rp0.2 and tensile strength Rm are tested. The test results are shown in Table 2 and Table 3.

[0170] Table 2: Performance results of non-oriented silicon steel in Examples and Comparative Examples

[0171]

[0172] Table 3: Performance results of non-oriented silicon steel in Examples and Comparative Examples

[0173]

[0174] It can be seen from Table 2 and Table 3 that due to the differences in some chemical compositions and process parameters, the performance stability of the embodiments and the comparative examples at different temperatures is significantly different: 15 / 50 The fluctuation in the temperature range of -40℃~200℃ is small, and the difference between the maximum and minimum values ​​is maintained between 0.17~0.24W / kg; 15 / 50The value is higher at low temperature (-40°C) (up to 2.72 W / kg), and the overall fluctuation is larger, with the difference between the maximum and minimum values ​​ranging from 0.18 to 0.4 W / kg; this indicates that the iron loss performance of the embodiment is more stable and suitable for a wider temperature range.

[0175] In the embodiment, each non-oriented silicon steel product has a 50 The difference between the maximum and minimum values ​​of the 50 The fluctuation range is 0.011~0.015T, and there is no obvious advantage at high temperature; the embodiment is better in magnetic property stability.

[0176] The Rp0.2 and Rm of each non-oriented silicon steel product in the embodiment show high and stable performance at different temperatures: the difference between the maximum and minimum values ​​of Rp0.2 is maintained at 85~95 MPa; the difference between the maximum and minimum values ​​of Rm is maintained at 70~80 MPa; the difference between the maximum and minimum values ​​of Rm in the comparative example ranges from 75~95 MPa, and Rp0.2 fluctuates more in the comparative example (the minimum is 290 MPa), and the difference between the maximum and minimum values ​​ranges from 90~120 MPa, indicating that the high and low temperature mechanical properties are unstable and severely attenuated at high temperatures, which is not conducive to the long-term operation of the motor.

[0177] The non-oriented silicon steel product of the embodiment of the present invention exhibits excellent performance stability in a wide temperature range of -40°C to 200°C. Compared with the comparative example: iron loss P 15 / 50 Low and stable, which is beneficial to energy efficiency control; magnetic induction intensity B 50 Small fluctuation ensures consistent magnetic properties; the yield strength and tensile strength (Rp0.2 and Rm) remain at high values, and the mechanical properties are excellent.

[0178] In summary, the present invention obtains a high-grade non-oriented silicon steel with a Si content of 2.8-3.5% and an Als content of 0.5-1.0% suitable for operation in a variable temperature environment through reasonable composition and process control. 1.5 / 50 ≤2.45W / kg, B 50 ≥1.65T, yield strength ≥350MPa, tensile strength ≥500Mpa, especially suitable for rotating motors.

[0179] Other parts not described belong to the prior art.

Claims

1. A method for producing low iron loss, high strength non-oriented silicon steel adaptable to different temperatures, characterized by: The following steps are involved: Hot metal pretreatment, converter smelting, RH refining, casting, hot rolling, normalizing treatment, primary cold rolling, annealing, and insulation coating; The hot rolling process adopts hot charging to carry out heating and hot rolling, the heating temperature of the slab is below 1150°C, and the slab temperature is maintained above 1100°C for not less than 50 minutes, and the total heating time of the slab does not exceed 200 minutes; During the normalizing process, when 3.5%≤(Si+Als)<4.0%, the normalizing temperature is 850-900°C; when 4.0%≤(Si+Als)≤4.25%, the normalizing temperature is 800-850°C, and Sn is added during molten iron smelting; wherein Si and Als refer to the weight percentage of the corresponding elements in the non-oriented silicon steel product; During the annealing process, radiation tube heating is first used to reach the high temperature section annealing temperature within 50 seconds and maintained for 45 to 60 seconds, and then resistance heating is used to control the annealing temperature in the process section and maintained for 30 to 50 seconds; before reaching the high temperature section annealing temperature, the strip temperature is ensured to be quickly heated to above 900°C within 20 seconds; the high temperature section annealing temperature must meet T 高温 ≥T 工艺 +20℃, the annealing temperature in the process section is 930~980℃, among which, T 高温 is the high temperature annealing temperature, T 工艺 is the annealing temperature of the process section; The non-oriented silicon steel includes the following chemical components in weight percentage: C≤0.0020%, Si: 2.8~3.5%, Mn: 0.25~0.65%, Als: 0.5~1.0%, S≤0.0015%, N≤0.0015%, Ti≤0.0020%, and 3.5%≤(Si+Als)≤4.25%, where Si and Als refer to the weight percentages of the corresponding elements in the non-oriented silicon steel product; when 4.0%≤(Si+Als), 0.02%≤Sn≤0.10% is added.

2. The manufacturing method according to claim 1, wherein: The thickness of the ingot obtained after the casting is 150-250 mm.

3. The manufacturing method according to claim 1, wherein: During the hot rolling process, the heated slab is rough-rolled for 5 or 3 passes and then finish-rolled to 1.8-2.5 mm on 7 stands; the intermediate slab thickness is 35-45 mm, the rough-rolling outlet temperature is ≥980°C, the finishing rolling temperature is 840-900°C, and the coiling temperature is 550-690°C.

4. The manufacturing method according to claim 1, wherein: After the normalizing treatment, the steel strip is cooled in sequence by water jacket cooling, air-mist cooling, and water spray cooling; the air-mist cooling cools the steel strip from the process temperature to 500°C; the water spray cooling cools the steel strip from 500°C to below 80°C; and a blower is used between the water jacket cooling and air-mist cooling sections to spray air onto the upper and lower surfaces of the steel strip.

5. The manufacturing method according to claim 1, wherein: During the annealing process, the atmosphere used is a nitrogen-hydrogen mixed atmosphere, the volume ratio of nitrogen to hydrogen is 7:3, the dew point is below -10°C, and the unit tension in the furnace during the annealing process is ≤2.5N / mm 2 .

6. The manufacturing method according to claim 1, wherein: The non-oriented silicon steel is within the range of -40℃~200℃: 1.5 / 50 ≤2.45W / kg, B 50 ≥1.65T, yield strength ≥350MPa, tensile strength ≥500Mpa.

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