High-grade non-oriented silicon steel with high favorable texture ratio and production method of high-grade non-oriented silicon steel

Abstract

According to the high-grade non-oriented silicon steel with the high favorable texture ratio and the production method of the high-grade non-oriented silicon steel, primary cold rolling reduction, the reduction rate of each pass and the reduction rate of secondary cold rolling are regulated and controlled, meanwhile, the normalizing procedure is replaced with the high intermediate annealing temperature, the cost is reduced, and the production efficiency is improved. A large grain size is obtained before secondary cold rolling, a large number of shear bands are formed on the surface layer and the center layer of the cold-rolled sheet after secondary cold rolling, the area of the shear bands is far larger than the area of a grain boundary, the cold-rolled sheet is promoted to become a leading position of recrystallization nucleation, and meanwhile more {hk0} lt is achieved through a three-section continuous annealing process suitable for subsequent procedures; 001gt, 001gt; and {hkl} lt; 110gt, 110gt; grains of the texture grow up, grains of other orientations are increased, and {hkl} lt is further reduced; 111gt, 111gt; the proportion of the texture and the magnetic induction intensity B50 of the product are improved by more than 0.018 T, and B50 is greater than or equal to 1.66 T.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-oriented electrical steel production, and in particular relates to a high-grade non-oriented silicon steel with a high proportion of favorable textures and a production method thereof. Background Art

[0002] As the requirements for energy conservation and emission reduction continue to increase, non-oriented silicon steel, as the raw material for making iron cores for various motors, generators, instruments and other equipment, must have electromagnetic properties with low iron loss and high magnetic induction. Non-oriented silicon steel is a polycrystalline, body-centered cubic structure composed of many ferromagnetic single crystals. The magnetization curves and the difficulty of magnetizing to saturation measured by magnetizing ferromagnetic single crystals along different crystal axis directions are different. <100> It is easiest to magnetize along the crystal axis. <111> The most difficult magnetization is in the crystal axis direction. <110> In between. The {100} crystal plane contains two <100> The crystal direction is easy magnetization axis without the most difficult magnetization axis. <111> The {110} crystal plane contains a <100> The crystal direction is easy magnetization axis without the most difficult magnetization axis. <111> crystal direction, while the {111} crystal plane does not contain <100> The crystal direction is easy to magnetize and contains a most difficult magnetization axis. <111> Crystal axis, so for non-oriented silicon steel, if you want to obtain higher magnetic properties, you want as many {hk0} as possible in the silicon steel plate. <001> and {hkl} <110> Favorable texture, as little as possible {hkl} <111> Unfavorable texture.

[0003] At present, according to the industrialized large-scale production mode of high-grade non-oriented silicon steel, the product undergoes steelmaking, hot rolling, normalizing, cold rolling, annealing, and the inheritance of hot-rolled thick slabs and organizational textures, resulting in the final texture being a weak α texture ( <110> / / RD) and strong γ texture ( <111> / / ND) composition, how to obtain strong α texture and weaken γ texture by accurately optimizing the production process has become a technical challenge in the research.

[0004] The Chinese patent with the publication number CN 104294023 A published on January 21, 2015 discloses a method for preparing high magnetic induction non-oriented electrical steel using columnar crystals, wherein a columnar crystal part is cut from a square ingot with a silicon content of 6.0% to 6.5%, and hot rolling, pickling, warm rolling, intermediate annealing, cold rolling and final annealing are performed along the normal direction of the columnar crystal to prepare the non-oriented silicon steel. The slab before hot rolling has <001> Preferentially oriented columnar crystal structure, by utilizing the heredity of {100} texture to prepare high magnetic induction non-oriented silicon steel. Although this technology has obvious effects, it is difficult to control the industrial large-scale production process.

[0005] The Chinese patent with publication number CN 113943884 A published on January 18, 2022 discloses a method for preparing a multi-component {100} textured non-oriented electrical steel, which comprises preparing a 1.5-2.5 mm thick non-oriented electrical steel cast strip by controlling the parameters of thin strip continuous casting, directly cold rolling it to a thickness of 0.35-0.50 mm, first performing pre-recovery annealing, and then performing finished product annealing. The prepared non-oriented electrical steel has a multi-component {100} texture, including {100} <001> , {100} <012> and {100} <011> , the volume fraction of the {100} texture component reaches 25-39%, thereby significantly improving the magnetic induction. Although this technology has obvious effects, it is not suitable for large-scale industrial production of continuous casting thick slabs.

[0006] A Chinese patent with publication number CN 114934164 A, published on August 23, 2022, discloses a method for increasing the proportion of favorable texture in high-grade non-oriented silicon steel. The method adds 0.045% to 0.100% of typical grain boundary segregation elements Sn or Sb to reduce the {111} texture. At the same time, the control of the production process is coordinated to increase the {100} and {110} components and weaken the {111} component, ultimately achieving the effect of increasing the proportion of favorable texture. However, it is not enough to rely solely on the segregation effect of elements. Small-sized precipitations have an impact on the pinning caused by grain boundaries and the cold rolling reduction rate. Summary of the invention

[0007] The purpose of the present invention is to provide a high-grade non-oriented silicon steel with a high proportion of favorable texture and a production method thereof, which uses large ingot production in conventional industrial large-scale production, optimizes the process, reasonably controls the reduction rate of the first cold rolling and each pass and the reduction rate of the second cold rolling, and replaces the normalizing process with a higher intermediate annealing temperature, and is matched with a three-stage continuous annealing process suitable for the subsequent process, so that more {hk0} <001> and {hkl} <110> The grains of the texture grow, and the grains of other orientations increase, further reducing {hkl} <111> The proportion of texture, {hk0} <001> and {hkl} <110> The volume percentage of texture reaches more than 48%.

[0008] The specific technical solutions of the present invention are as follows:

[0009] The present invention provides a high-grade non-oriented silicon steel with a high favorable texture ratio, comprising the following components in percentage by mass:

[0010] C≤0.0030%, Si: 2.65%~3.5%, Mn: 0.15%~0.55%, Als: 0.3%~1.5%, P≤0.025%, S≤0.0025%, Ti≤0.0020%, N≤0.0020%, 0.03%≤Sn<0.11%, and the rest are Fe and unavoidable impurities.

[0011] The composition of the high-grade non-oriented silicon steel with a high proportion of favorable texture also satisfies Σ wt (C+S+N+Ti)≤65ppm; that is, in the composition of high-grade non-oriented silicon steel with a high proportion of favorable texture, the total content of C, S, N and Ti is ≤65ppm. C, S, N and Ti are impurity elements, and their total content is controlled.

[0012] The composition of the high-grade non-oriented silicon steel with a high favorable texture ratio also satisfies 0.0343≤Σ wt (Si+Mn+Als+Sn)<0.0511. That is, in the composition of high-grade non-oriented silicon steel with a high proportion of favorable texture, the total content of Si, Mn, Als and Sn is 0.0343≤Σ wt (Si+Mn+Als+Sn)<0.0511. These four elements are the main alloying elements, which improve resistivity and reduce iron loss. If they are below a certain range, the iron loss and performance described in the present invention cannot be achieved even through process technology and texture optimization. This formula is calculated as the content of Si, Mn, Als and Sn. For example, if the Si content is 2.65%, the value is 0.0265.

[0013] The high-grade non-oriented silicon steel having a high proportion of favorable textures has a <001> and {hkl} <110> The volume percentage of texture reaches more than 48%;

[0014] The high-grade non-oriented silicon steel having a high proportion of favorable texture {hkl} <111> Orientation strength decreased by 20%;

[0015] The iron loss P of the high-grade non-oriented silicon steel with a high proportion of favorable texture is 1.5 / 50 ≤2.35W / kg,

[0016] P 1.0 / 400 ≤16.5W / kg, B 50 ≥1.66T;

[0017] The thickness of the high-grade non-oriented silicon steel with a high favorable texture ratio is ≤0.35 mm.

[0018] The present invention provides a method for producing high-grade non-oriented silicon steel with a high favorable texture ratio, comprising the following processes:

[0019] Ingot heating, hot rolling, primary cold rolling, intermediate annealing, secondary cold rolling, continuous annealing.

[0020] The ingot refers to steel that meets the chemical composition requirements, which is subjected to molten iron pretreatment, converter steelmaking, vacuum treatment, and then continuously cast into an ingot with a thickness of 150 to 250 mm;

[0021] The ingot is cooled to a temperature not lower than 500°C and then enters a heating furnace for heating;

[0022] The billet heating means that the billet is heated in a heating furnace, the temperature of the heating furnace is 1100-1200°C, and the heating and heat preservation time is ≥210min;

[0023] The hot rolling, the final rolling temperature of the hot rolling is 830-890°C, and the coiling is carried out after cooling to 680-710°C. A higher coiling temperature is conducive to the effect of the segregated elements, and the hot rolled plate is obtained after coiling;

[0024] The thickness d of the hot rolled plate 热 , d 热 Satisfies: When 0.0343≤Σ wt When (Si+Mn+Als+Sn)<0.03855, d 热 Not more than 3.0mm; when 0.03855≤Σ wt When (Si+Mn+Als+Sn)<0.0511, d 热 Not exceeding 2.2mm; considering the subsequent total reduction rate, and generally the high content is the final thin specification products, so under the control of the total reduction, the thickness of the hot-rolled plate should not be too thick; the greater the total reduction rate, the stronger the unfavorable texture contained in the final product.

[0025] The first cold rolling is carried out according to the thickness d of the hot rolled plate. 热 The primary cold rolling reduction rate is adjusted according to the target thickness and the secondary cold rolling reduction rate control range, and rolled to the intermediate thickness d 中 The main texture components of the formed fiber structure are {hk0} with strong orientation density. <100> Texture, {hkl} <110> Texture and orientation density are very weak {hkl} <111> Texture;

[0026] The reduction rate R1 of the first cold rolling does not exceed 70%. When the reduction rate of the first cold rolling is too large and exceeds a certain value, the grain size of the final product will decrease by 5 to 10 μm, which will worsen the iron loss of the product.

[0027] In the cold rolling, the reduction rate of the last pass is set at 15%, and the reduction rates of the previous passes should be set to be consistent to reduce the {111} <111> Texture and {111} <112> The rapid increase of unfavorable textures.

[0028] The intermediate annealing is to perform intermediate annealing at 930-980°C for a time of 2 minutes on the primary cold-rolled sheet. The annealing atmosphere is H2 and N2 as the protective atmosphere, the volume ratio of H2 and N2 is 3:7, and the dew point in the furnace is controlled at (-40)-(-10)°C. The use of a higher intermediate annealing temperature can, on the one hand, replace the effect of the normalizing process and reduce production and process costs; on the other hand, the intermediate annealed product before the final cold rolling has a larger average grain size, paving the way for the subsequent formation of more shear bands, while reducing the grain boundaries, i.e. {hkl} <111> Location of texture nucleation;

[0029] The secondary cold rolling is to perform secondary cold rolling on the intermediate annealed sheet to a target thickness of 0.35 mm or less. The secondary cold rolling reduction ratio R2 must satisfy: -3034.547×[Σ wt (Si+Mn+Als+Sn)] 2 +270.168×Σ wt (Si+Mn+Als+Sn)-5.455<R2<-3647.292×

[0030] [Σ wt (Si+Mn+Als+Sn)] 2 +316.308×Σ wt (Si+Mn+Als+Sn)-6.123; the steel plate structure after secondary cold rolling has a large area of ​​shear bands, which far exceeds the grain boundary, making the shear band the dominant position for recrystallization nucleation in the subsequent annealing process. At the same time, when the main alloy composition is certain, the range of cold rolling reduction rate is strictly required, because the reduction rolling is the process of flow and plastic deformation of these metal elements and compounds. When the secondary cold rolling reduction rate exceeds a certain range, it is difficult to obtain a large number of large-area shear band structures, making it the dominant position for recrystallization nucleation in the subsequent continuous annealing process. Therefore, the range of secondary cold rolling reduction rate requirements is closely related to the content of the main alloy elements.

[0031] The continuous annealing refers to a three-stage recrystallization continuous annealing of the secondary cold rolled sheet in the preheating stage, the heating stage and the soaking stage. The annealing is performed in a mixed atmosphere of H2 and N2, with the volume ratio of hydrogen being not less than 30%. After the continuous annealing, the surface of the strip is coated with an insulating coating to obtain the final product.

[0032] The preheating temperature in the continuous annealing is 750-900°C, the holding time is 5-10s, and the recrystallization annealing includes the recovery, recrystallization and growth process of the grains. Annealing at a lower preheating temperature reduces the degree of recovery, leaving more storage energy as the driving force for recrystallization, thus increasing the randomness of the initial recrystallization texture components, thereby increasing and determining the final texture components and types, and further weakening the strength of the {111} plane texture.

[0033] The heating stage in the continuous annealing is heated at a relatively fast heating rate of 60°C / s to 100°C / s, and is quickly heated to a relatively high annealing temperature of 970 to 1010°C, and is kept warm for 5 to 10s. The relatively high heating rate and relatively high annealing temperature are beneficial to the growth of grains and the reduction of iron loss.

[0034] The temperature of the soaking section in the continuous annealing is 940° C. to 990° C. and is kept at this temperature for 25 seconds to 40 seconds, so as to promote further growth of grains with favorable texture.

[0035] The role of each element in steel is as follows:

[0036] Si: Si is an element that increases resistance and is the most important alloying element in electrical steel. To obtain low iron loss, the Si content needs to be increased. However, an increase in Si content will increase the strength of the steel, causing the steel to break due to brittle deformation during cold working.

[0037] 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.

[0038] Als: Aluminum has a similar effect to silicon, increasing the ρ value, reducing the γ zone and promoting grain growth, reducing iron loss and increasing the strength of steel.

[0039] Si, Mn and Al are important alloying elements for electrical steel. Only when their contents reach a certain level can a certain required low iron loss performance be achieved. At the same time, if their contents exceed a certain value, the cold hardness of the product will be increased, the elongation of the product will be reduced, and cold rolling fracture will occur during cold rolling.

[0040] Sn: A segregated element on the surface and grain boundaries of electrical steel, it will inhibit the {111} texture that first nucleates at the grain boundaries, weaken the strength of the {111} texture, and increase the components of the {110} and {100} textures. However, when it exceeds 0.11%, the segregation at the grain boundaries can effectively inhibit the migration of the grain boundaries, resulting in a reduction in the grain size, which is not conducive to the magnetic properties of the product.

[0041] Therefore, in summary, when the contents of the four main alloying elements are generally within the following range: 0.0343≤Σwt(Si+Mn+Als+Sn)<0.0511, the product as a whole can achieve a good level of magnetic properties.

[0042] C, S, N, Ti: harmful elements. When the C content exceeds 0.003%, magnetic aging will occur, resulting in deterioration of iron loss during the use of silicon steel. It has the advantages of increasing coercive force and hysteresis loss while reducing magnetic induction intensity. When the S and N contents are high, a large amount of inclusions such as MnS, Cu2S and AlN will be generated, affecting the performance of silicon steel. The important goal of the ingot heating, hot rolling and normalizing processes is to control the precipitation of fine MnS particles and coarsen the existing MnS. When the Ti content increases, a large amount of fine and stable Ti (CN) inclusions will be formed, which will hinder grain growth, increase the {111} grains in the finished product, and reduce the {100} grains. Therefore, the present invention controls (C+S+N+Ti)≤65ppm.

[0043] Compared with the prior art, the present invention reasonably regulates the reduction rate of the first cold rolling and each pass and the reduction rate of the second cold rolling, and replaces the normalizing process with a higher intermediate annealing temperature, which not only reduces the cost, but also obtains a larger grain size before the second cold rolling. A large number of shear bands are formed on the surface layer and the center layer of the cold-rolled sheet after the second cold rolling, and the area is far greater than the area of ​​the grain boundary, which makes a large number of shear bands become the dominant position of recrystallization nucleation. At the same time, with a suitable three-stage continuous annealing process in the subsequent process, more {hk0} <001> and {hkl} <110> The grains of the texture grow, and the grains of other orientations increase, further reducing {hkl} <111> The proportion of texture is obtained, and a production Si content is above 2.65%, and the finished product thickness is 0.35mm and below, with {hk0} <001> and {hkl} <110> The volume percentage of texture reaches more than 48%, which is unfavorable texture {hkl} <111> Orientation strength decreased by 20%, product saturation magnetic induction intensity B 50 Increase by more than 0.018T, iron loss P 1.5 / 50 ≤2.35W / kg, P 1.0 / 400 ≤16.5W / kg, B 50 ≥1.66T, the cost can be reduced by about 10% for high-grade non-oriented silicon steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The cold-rolled sheet structure after secondary cold rolling in Example 1;

[0045] Figure 2 This is the finished product structure after annealing in Example 1;

[0046] Figure 3 This is the cold-rolled sheet structure after one cold rolling in Comparative Example 1;

[0047] Figure 4 This is the structure after intermediate annealing in Comparative Example 2;

[0048] Figure 5 This is the finished product structure after final annealing of Comparative Example 3;

[0049] Figure 6 This is the finished product structure of Comparative Example 4 after final annealing. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Example 1

[0052] A high grade non-oriented silicon steel with a high proportion of favorable textures comprises the following components in mass percentage: as shown in Table 1, the remainder not shown in Table 1 is Fe and unavoidable impurities.

[0053] Table 1 Chemical composition of each embodiment and comparative example, wt%

[0054]

[0055] The method for producing high-grade non-oriented silicon steel with a high favorable texture ratio described in Example 1 comprises the following steps:

[0056] 1) After molten iron pretreatment, converter steelmaking and vacuum treatment, molten steel with the composition in accordance with the requirements in Table 1 is obtained, and continuously cast into 230 mm ingots;

[0057] 2) After the ingot is cooled, it is heated and hot rolled at a temperature not lower than 500°C by hot charging, with a heating soaking temperature of 1130°C and a heating time of 250min;

[0058] 3) Hot rolling: hot rolling is carried out, and the final rolling temperature is controlled at 860℃ and 700℃, and then coiled to obtain d 热 = Hot rolled plate after 2.2mm;

[0059] 4) One-pass cold rolling to a thickness of 0.70 mm, with a total cold rolling reduction rate R1 of 68%, and four-pass rolling, with the last pass reduction rate set at 15%, and the first three passes reduction rates set at 27.9%;

[0060] 5) Perform intermediate annealing at 960°C for 2 minutes; use H2 and N2 as protective atmosphere in a ratio of 3:7, and control the dew point in the furnace at -40 to -10°C;

[0061] 6) Secondary cold rolling to 0.25 mm, the total reduction ratio R2 of the secondary cold rolling is 64%, satisfying the formula -3034.547×[Σ wt (Si+Mn+Als+Sn)] 2 +270.168×Σ wt (Si+Mn+Als+Sn)-5.455<R2<-3647.292×[Σ wt (Si+Mn+Als+Sn)] 2 +316.308×Σ wt (Si+Mn+Als+Sn)-6.123, that is, 0.5577<0.64<0.733;

[0062] 7) After three-stage annealing, the temperature of the first preheating section is 850°C and the holding time is 8s; the second section adopts an annealing heating rate of 80°C / s, rapidly heated to 1000°C, and kept warm for 8s; the temperature of the soaking section is 990°C, kept warm for 30s, H2 and N2 are used as protective atmosphere in a volume ratio of 3:7, and the dew point in the furnace is controlled below -10°C; the favorable texture ratio and magnetic properties of the final product are shown in Example 1 in Table 3.

[0063] Comparative Example 1

[0064] A method for producing non-oriented silicon steel, wherein the chemical composition weight percentage of the steel is as shown in Table 1, Comparative Example 1, and the remainder is iron and unavoidable impurity elements.

[0065] The ingredients in Comparative Example 1 all meet the requirements of the present invention, and the manufacturing method is the same as that in Example 1, except that during the first cold rolling, once Cold rolled to 0.50mm, the total reduction rate R1 of one cold rolling is 77.3%, which is greater than 70% At the same time, the cold rolling was performed in five passes with reduction rates set at 35%, 29%, 25%, 20%, and 17% respectively. The favorable texture ratio and magnetic properties obtained are shown in Comparative Example 1 in Table 3.

[0066] Comparative Example 2

[0067] A method for producing non-oriented silicon steel, wherein the chemical composition weight percentage of the steel is as shown in Table 1, Comparative Example 2, and the remainder is iron and unavoidable impurity elements.

[0068] The ingredients in Comparative Example 2 all meet the requirements of the present invention, and the manufacturing method is the same as that in Example 1, except that Before cold rolling The hot rolled plate was normalized at 840℃. After one cold rolling The intermediate annealing temperature is 910℃. The favorable texture ratio and magnetic properties obtained are shown in Comparative Example 2 in Table 3.

[0069] Comparative Example 3

[0070] A method for producing non-oriented silicon steel, wherein the chemical composition weight percentage of the steel is as shown in Table 1, Comparative Example 3, and the remainder is iron and unavoidable impurity elements.

[0071] The ingredients in Comparative Example 3 all meet the requirements of the present invention, and the manufacturing method is the same as that in Example 1, except that during continuous annealing, No. The temperature of the first preheating section is selected to be 950℃ , keep warm for 5s, The second heating rate is 17℃ / s Heating to 1000°C and keeping warm for 8s, and then keeping warm at 990°C for 30s, the favorable texture ratio and magnetic properties obtained are shown in Comparative Example 3 in Table 3.

[0072] Comparative Example 4

[0073] A method for producing non-oriented silicon steel, wherein the chemical composition weight percentage of the steel is as shown in Table 1, Comparative Example 4, and the remainder is iron and unavoidable impurity elements.

[0074] The ingredients in Comparative Example 4 all meet the requirements of the present invention, and the manufacturing method is the same as that in Example 1, except that the normalizing temperature before cold rolling is 840°C. The first cold rolling is to 0.50mm, and the first cold rolling reduction ratio R1 is 77.3%, which is greater than 70%. Second cold rolling reduction R2 is 0.5 <0.5577, does not meet the requirements of R2 formula , Intermediate annealing temperature 910℃, And in the final annealing process, The first preheating temperature The temperature is 950℃. Keep warm for 5 seconds; The second heating rate is 17℃ / s Heating to 1000°C and keeping warm for 8s; then keeping warm at 990°C for 30s, the favorable texture ratio and magnetic properties obtained are shown in Table 3 Comparative Example 4.

[0075] Example 2

[0076] A high grade non-oriented silicon steel with a high proportion of favorable textures comprises the following components in mass percentage: as shown in Table 1, the remainder not shown in Table 1 is Fe and unavoidable impurities.

[0077] The method for producing high-grade non-oriented silicon steel with a high proportion of favorable textures described in Example 2 comprises the following process steps:

[0078] 1) After molten iron pretreatment, converter steelmaking and vacuum treatment, molten steel with the composition in accordance with the requirements in Table 1 is obtained, and continuously cast into 230 mm ingots;

[0079] 2) After the ingot is cooled, it is heated and hot rolled at a temperature not lower than 500°C by hot charging, with a heating soaking temperature of 1130°C and a heating time of 250min;

[0080] 3) Then hot rolling is carried out, final rolling is controlled at 860℃, and coiling is carried out at 700℃ to obtain d 热 = Hot rolled plate after 2.5mm;

[0081] 4) One cold rolling to a thickness of 0.80 mm, the total reduction rate R1 of one cold rolling is 68%, and the rolling is divided into four passes, the reduction rate of the last pass is set at 15%, and the reduction rates of the first three passes are all set at 27.9%;

[0082] 5) Perform intermediate annealing at 940°C for 2 minutes; use H2 and N2 as protective atmosphere in a volume ratio of 3:7, and control the dew point in the furnace at -40 to -10°C;

[0083] 6) Secondary cold rolling to 0.30 mm, the total reduction rate R2 of the secondary cold rolling is 62.5%, satisfying the formula -3034.547×[Σ wt (Si+Mn+Als+Sn)] 2 +270.168×Σ wt (Si+Mn+Als+Sn)-5.455<R2<-3647.292×[Σ wt (Si+Mn+Als+Sn)] 2 +316.308×Σ wt (Si+Mn+Als+Sn)-6.123, that is, 0.4411<0.625<0.6414;

[0084] 7) After three-stage annealing, the temperature of the first preheating section is 800°C and the temperature is kept for 8s. The second section adopts an annealing heating rate of 70°C / s, rapidly heated to 980°C, and kept for 8s; the temperature of the soaking section is 960°C and kept for 25s. H2 and N2 are used as protective atmosphere in a volume ratio of 3:7, and the dew point in the furnace is controlled below -10°C; the favorable texture ratio and magnetic properties of the final product are shown in Table 3 Example 2.

[0085] Comparative Example 5

[0086] A method for producing non-oriented silicon steel, wherein the chemical composition weight percentage of the steel is as shown in Table 1, Comparative Example 5, and the remainder is iron and unavoidable impurity elements.

[0087] The ingredients in Comparative Example 5 all meet the requirements of the present invention, and the manufacturing method is the same as that in Example 2, except that the cold rolling is performed once to 1.0 mm, and the total cold rolling reduction R1 is 60%, which meets the requirements. However, the five-pass rolling reduction ratios are 25%, 19%, 17%, 13% and 9% are set for rolling. The total reduction ratio R2 of the secondary cold rolling is 70%, which does not satisfy the formula 0.4411<R2<0.6414. The favorable texture ratio and magnetic properties obtained are shown in Comparative Example 5 in Table 3.

[0088] Comparative Example 6

[0089] A method for producing non-oriented silicon steel, wherein the chemical composition weight percentage of the steel is as shown in Table 1, Comparative Example 6, and the remainder is iron and unavoidable impurity elements.

[0090] The ingredients in Comparative Example 2 all meet the requirements of the present invention, and the manufacturing method is the same as that in Example 2, except that Before cold rolling The hot rolled plate was normalized at 860°C, and the intermediate annealing temperature after the first cold rolling was 910°C. The favorable texture ratio and magnetic properties obtained are shown in Comparative Example 6 in Table 3.

[0091] Comparative Example 7

[0092] A method for producing non-oriented silicon steel, wherein the chemical composition weight percentage of the steel is as shown in Table 1, Comparative Example 7, and the remainder is iron and unavoidable impurity elements.

[0093] The ingredients in Comparative Example 1 all meet the requirements of the present invention, and the manufacturing method is the same as that in Example 2, except that in the final annealing process, The first preheating temperature is 930℃. Keep warm for 8s, The second heating rate is 17℃ / s Heating to 980°C, keeping warm for 8s, and then keeping warm at 960°C for 25s, the favorable texture ratio and magnetic properties obtained are shown in Comparative Example 7 in Table 3.

[0094] Comparative Example 8

[0095] A method for producing non-oriented silicon steel, wherein the chemical composition weight percentage of the steel is as shown in Table 1, Example 8, and the remainder is iron and unavoidable impurity elements.

[0096] The ingredients in Comparative Example 1 all meet the requirements of the present invention, and the manufacturing method is the same as that in Example 2, except that the steel is cold-rolled to 1.0 mm once, and the cold-rolling reduction ratio R1 is 60%. The secondary cold rolling reduction ratio R2 is 70%, which does not satisfy the formula 0.4411<R2< 0.6414 , Intermediate annealing temperature 910℃ , and during continuous annealing The first preheating temperature is 930℃. Keep warm for 8s, second Heating rate: 17℃ / s Heating to 980°C, keeping warm for 8s, and then keeping warm at 960°C for 25s, the favorable texture ratio and magnetic properties obtained are shown in Comparative Example 8 in Table 3.

[0097] Table 3 Magnetic properties measurement results of various embodiments and comparative examples and Epstein square ring

[0098]

[0099]

[0100] The underlined data above do not meet the requirements of the present invention.

[0101] The description of the above embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A high-grade non-oriented silicon steel with a high proportion of favorable texture, characterized in that: The high-grade non-oriented silicon steel with a high proportion of favorable texture comprises the following components in mass percentage: C≤0.0030%, Si: 2.65%~3.5%, Mn: 0.15%~0.55%, Als: 0.3%~1.5%, P≤0.025%, S≤0.0025%, Ti≤0.0020%, N≤0.0020%, 0.03%≤Sn<0.11%, and the rest are Fe and unavoidable impurities.

2. The high-grade non-oriented silicon steel with a high favorable texture ratio according to claim 1, characterized in that: The composition of the high-grade non-oriented silicon steel with a high favorable texture ratio also satisfies 0.0343≤Σ wt (Si+Mn+Als+Sn)<0.0511.

3. The high-grade non-oriented silicon steel with a high favorable texture ratio according to claim 1 or 2, characterized in that: The high-grade non-oriented silicon steel having a high proportion of favorable textures has a <001> and {hkl} <110> The volume percentage of texture reaches more than 48%.

4. A method for producing high-grade non-oriented silicon steel with a high proportion of favorable textures according to any one of claims 1 to 3, characterized in that: The production method comprises the following processes: Ingot heating, hot rolling, primary cold rolling, intermediate annealing, secondary cold rolling, continuous annealing.

5. The production method according to claim 4, characterized in that: The hot rolling has a final rolling temperature of 830-890° C. and is cooled to 680-710° C. for coiling.

6. The production method according to claim 4, characterized in that: The thickness d of the hot rolled plate 热 , d 热 Satisfies: When 0.0343≤Σ wt When (Si+Mn+Als+Sn)<0.03855, d 热 Not more than 3.0mm; when 0.03855≤Σ wt When (Si+Mn+Als+Sn)<0.0511, d 热 No more than 2.2mm.

7. The production method according to claim 4, characterized in that: In the single cold rolling, the reduction rate R1 does not exceed 70%; in the single cold rolling, the reduction rate of the last pass is set at 15%, and the reduction rates of the previous passes are the same.

8. The production method according to claim 4, characterized in that: The intermediate annealing has an annealing temperature of 930-980° C. and an annealing time of 2 minutes.

9. The production method according to claim 4, characterized in that: The secondary cold rolling is to perform secondary cold rolling on the intermediate annealed sheet to a target thickness of 0.35 mm or less. The secondary cold rolling reduction ratio R2 must satisfy: -3034.547×[Σ wt (Si+Mn+Al+Sn)] 2 +270.168× Σ wt (Si+Mn+Al+Sn)-5.455<R2<-3647.292×[Σ wt (Si+Mn+Al+Sn)] 2 +316,308×S wt (Si+Mn+Al+Sn)-6.

123.

10. The production method according to claim 4, characterized in that: The continuous annealing comprises a three-stage recrystallization continuous annealing of a preheating stage, a heating stage and a soaking stage; the preheating stage temperature is 750-900°C, and the holding time is 5-10s; the heating stage: the heating rate is 60°C / s-100°C / s, the annealing temperature is heated to 970-1010°C, and the holding time is 5-10s; the soaking stage temperature is 940°C-990°C, and the holding time is 25s-40s.

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