High-silicon high-performance non-oriented electrical steel and preparation method thereof

Abstract

The invention discloses high-silicon high-performance non-oriented electrical steel and a preparation method thereof. The method comprises the steps that molten steel is provided for vacuum induction smelting and heat preservation treatment, and a continuous casting steel billet is formed through air free forging; the continuous casting steel billet is heated to 1000-1400 DEG C, heat preservation is conducted, and a heated steel billet is obtained; carrying out hot rolling treatment on the heated steel billet to obtain a hot-rolled plate; normalizing the hot-rolled plate to obtain normalized steel; warm rolling treatment is conducted on the normalized steel, specifically, first warm rolling treatment is conducted on the normalized steel in the HRD direction, and a first warm-rolled steel billet is obtained; second warm rolling treatment in the HTD direction is conducted on the first warm rolling steel billet, intermediate annealing treatment is conducted on the warm rolling plate at the temperature of 900-1000 DEG C in the warm rolling treatment process, cooling is conducted after annealing, and a cooled warm rolling plate is obtained; the cooled warm-rolled plate is subjected to multi-pass cold rolling treatment in the CTD and / or RD sampling direction, and a cold-rolled sheet is obtained; and the cold-rolled sheet is subjected to final annealing treatment, and the high-silicon high-performance non-oriented electrical steel is obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of silicon steel, and particularly relates to a high-silicon high-performance non-oriented electrical steel and a preparation method thereof. BACKGROUND

[0002] At present, under the background of energy crisis and environmental protection, new energy vehicles develop rapidly, non-oriented silicon steel as one of the raw materials of the driving motor of the core component of new energy vehicles, the market demand is also increasing year by year. And the development of new energy vehicles puts forward more strict requirements for non-oriented silicon steel: the motor needs to output high enough torque when the car starts, which means that non-oriented silicon steel needs to have higher magnetic induction intensity. The high-frequency low-iron loss and zero-magnetic-strain characteristics of silicon steel containing 6.5wt.%Si make it particularly suitable for use as driving motor core material, but the decrease of magnetic induction intensity caused by the increase of Si content makes it need to improve the magnetic properties by optimizing the texture. SUMMARY

[0003] The embodiment of the application provides a high-silicon high-performance non-oriented electrical steel and a preparation method thereof, which is aimed at silicon steel containing 6.5wt.%Si, adopts warm rolling, cross rolling and other methods to improve the magnetic properties, and obtains high-performance non-oriented electrical steel.

[0004] In a first aspect, the application provides a preparation method of a high-silicon high-performance non-oriented electrical steel, comprising: providing molten steel of non-oriented electrical steel; vacuum induction smelting the molten steel of non-oriented electrical steel, and carrying out heat preservation treatment at 1000-1200 DEG C, and adopting air free forging to form a continuous casting billet; carrying out heating treatment on the continuous casting billet, heating the continuous casting billet to 1000-1400 DEG C, heat preservation for a first preset time, and obtaining a heated billet; carrying out hot rolling treatment on the heated billet, and obtaining a hot-rolled plate; carrying out normalizing treatment on the hot-rolled plate at 850-1050 DEG C, the normalizing time being a second preset time, and obtaining normalized steel; carrying out warm rolling treatment on the normalized steel, comprising: carrying out first warm rolling treatment on the normalized steel at 600-700 DEG C and under the condition that the reduction is 75-80%, the sampling direction being HRD, obtaining a first warm-rolled billet; carrying out second warm rolling treatment on the first warm-rolled billet at 400-500 DEG C and under the condition that the reduction is 45-50%, the sampling direction being HTD, and carrying out intermediate annealing treatment on the warm-rolled plate at 900-1000 DEG C for a third preset time in the process of warm rolling treatment, and carrying out cooling after annealing, obtaining a cooled warm-rolled plate; carrying out multi-pass cold rolling treatment on the cooled warm-rolled plate by adopting CTD and / or HRD sampling direction, and obtaining a cold-rolled sheet. The cold-rolled sheet is subjected to a final annealing treatment at 750-850 DEG C under the action of a protective gas for a fourth preset time period, to obtain high-silicon high-performance non-oriented electrical steel.

[0005] According to the embodiment of the first aspect of the present application, the molten steel of the non-oriented electrical steel includes the following components in percentage by mass: C: 0.002wt.%-0.005wt.%, Si: 6.0wt.%-6.5wt.%, Mn: 0.2wt.%-0.3wt.%, S: <0.005%, and the balance being iron and inevitable impurities.

[0006] According to the embodiment of the first aspect of the present application, the size of the continuous casting billet is 120mm in width and 30mm in height.

[0007] According to the embodiment of the first aspect of the present application, the first preset time period for heating the continuous casting billet to 1000-1400 DEG C for holding treatment is 30-60 minutes.

[0008] According to the embodiment of the first aspect of the present application, the continuous casting billet is heated using a high-temperature resistance heating box-type furnace.

[0009] According to the embodiment of the first aspect of the present application, the heated billet is subjected to hot rolling treatment using a φ330-350mm double-roller hot rolling mill; wherein φ330-350mm represents a roller diameter of 330-350mm.

[0010] According to the embodiment of the first aspect of the present application, the heated billet is subjected to multi-pass hot rolling treatment.

[0011] According to the embodiment of the first aspect of the present application, the thickness of the hot-rolled sheet is 3.0-3.4mm.

[0012] According to the embodiment of the first aspect of the present application, the normalized steel material is subjected to first warm rolling treatment using a φ330-350mm four-roller cold / warm rolling mill; wherein φ330-350mm represents a roller diameter of 330-350mm.

[0013] According to the embodiment of the first aspect of the present application, the second preset time period for normalization treatment is 4-12 minutes.

[0014] According to the embodiment of the first aspect of the present application, the third preset time period for intermediate annealing treatment is 8-10 minutes.

[0015] According to the embodiment of the first aspect of the present application, the cooled warm-rolled sheet is subjected to cold rolling treatment using a Φ120x350mm four-roller cold / warm rolling mill.

[0016] According to the embodiment of the first aspect of the present application, the thickness of the cold-rolled sheet is 0.25mm-0.35mm.

[0017] According to the embodiment of the first aspect of the present application, the cold-rolled sheet is subjected to a final annealing holding treatment using a silicon steel high-temperature annealing furnace.

[0018] According to the embodiment of the first aspect of the present application, the fourth preset time length is 35 minutes-45 minutes.

[0019] According to the embodiment of the first aspect of the present application, the protective gas is an inert gas.

[0020] According to the embodiment of the first aspect of the present application, the protective gas includes at least one of He, Ar, and N2.

[0021] In the second aspect, the present application provides a high-silicon high-performance non-oriented electrical steel, which is prepared according to the preparation method of the high-silicon high-performance non-oriented electrical steel provided in the embodiment of the first aspect.

[0022] According to the embodiment of the second aspect of the present application, the high-silicon high-performance non-oriented electrical steel includes the following textures: Goss texture, content is 17.1%-19.5%; lambda texture, content is 15.7%-17.2%; gamma texture, 27.3%-28.1%.

[0023] According to the embodiment of the second aspect of the present application, the magnetic properties of the high-silicon high-performance non-oriented electrical steel are as follows: P 15 / 50 is 2.39W / Kg-2.5W / Kg, P 10 / 400 is 13.51W / Kg-14.90W / Kg, B 50 is 1.50T-1.55T.

[0024] In view of the fact that the magnetic properties of the high-silicon non-oriented electrical steel are degraded due to the increase of the silicon content, the preparation method of the high-silicon high-performance non-oriented electrical steel provided in the embodiment improves the magnetic properties of the high-silicon non-oriented electrical steel by optimizing the texture of the continuous casting slab on the basis of the traditional high-silicon non-oriented electrical steel production process. The rolling angle of the warm-rolled sheet is controlled after the hot-rolled sheet is normalized and warm-rolled, the intermediate annealing treatment after the warm-rolling treatment, and the multi-pass cold-rolling treatment. Finally, the cold-rolled sheet is subjected to a final annealing treatment, thereby producing the high-silicon high-performance non-oriented electrical steel based on the rolling mode. The high-silicon non-oriented electrical steel with high magnetic induction and low iron loss is produced. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows. Those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0026] Figure 1 is a flowchart of the preparation method of high-silicon high-performance non-oriented electrical steel provided by the embodiments of the present application.

[0027] Figure 2 is a schematic diagram of the preparation method of high-silicon high-performance non-oriented electrical steel of Comparative Example 1, in which the second warm rolling treatment is performed along the HRD direction in the warm rolling stage.

[0028] Figure 3 is a schematic diagram of the preparation method of high-silicon high-performance non-oriented electrical steel of Embodiments 1-4, in which the second warm rolling treatment is performed along the respective HTD direction in the warm rolling stage.

[0029] Figure 4 is a schematic diagram of the preparation method of high-silicon high-performance non-oriented electrical steel of Comparative Example 1 and Embodiments 1-4, in which the cold rolling treatment is performed along the respective direction in the warm and cold rolling stage.

[0030] Figure 5 is the Oim and ODF diagram of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1.

[0031] Figure 6 is the Oim and ODF diagram of the high-silicon high-performance non-oriented electrical steel of Embodiment 1.

[0032] Figure 7 is the Oim and ODF diagram of the high-silicon high-performance non-oriented electrical steel of Embodiment 2.

[0033] Figure 8 is the Oim and ODF diagram of the high-silicon high-performance non-oriented electrical steel of Embodiment 3.

[0034] Figure 9 is the Oim and ODF diagram of the high-silicon high-performance non-oriented electrical steel of Embodiment 4.

[0035] Figure 10 is a comparison diagram of the magnetic properties data of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 and Embodiments 1-4.

[0036] It should be noted that, Figures 2 to 4 the red arrow in the above-mentioned diagram, i.e., the direction corresponding to the rolling in the corresponding stage in the preparation method. DETAILED DESCRIPTION

[0037] The features and exemplary embodiments of various aspects of the present application will be described below in detail, in order to make the purposes, technical solutions and advantages of the present application more clear and apparent, the present application will be further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, but not to limit the present application. For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0038] It should be noted that, in this paper, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the elements defined by the statement "include" do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

[0039] In order to solve the problems in the prior art, the embodiments of the present application provide a high-silicon high-performance non-oriented electrical steel and a preparation method thereof. First, the preparation method of the high-silicon high-performance non-oriented electrical steel provided by the embodiments of the present application will be introduced.

[0040] Figure 1 The flowchart of the preparation method of the high-silicon high-performance non-oriented electrical steel provided by an embodiment of the present application is shown. As shown in Figure 1 The preparation method of the high-silicon high-performance non-oriented electrical steel includes: providing molten steel of non-oriented electrical steel; vacuum induction smelting the molten steel of non-oriented electrical steel, and heat preservation treatment at 1000-1200℃, and air free forging into continuous casting billet; heating treatment of the continuous casting billet, heating the continuous casting billet to 1000-1400℃, heat preservation for a first preset time, to obtain a heated billet; hot rolling treatment of the heated billet to obtain a hot rolled plate; normalization treatment of the hot rolled plate at 850-1050℃, the normalization time being a second preset time, to obtain normalized steel; The warm rolling treatment of the normalized steel material includes: performing first warm rolling treatment on the normalized steel material under the condition of 600-700 DEG C and reduction of 75-80%, and the sampling direction is HRD, to obtain first warm rolling billet; performing second warm rolling treatment on the first warm rolling billet under the condition of 400-500 DEG C and reduction of 45-50%, and the sampling direction is HTD, and performing intermediate annealing treatment on the warm rolling plate at 900-1000 DEG C for a third preset time length during the warm rolling treatment, and cooling after the annealing, to obtain the cooled warm rolling plate. Performing multi-pass cold rolling treatment on the cooled warm rolling plate in the CTD and / or CRD sampling direction, to obtain a cold rolling sheet. Performing final annealing treatment on the cold rolling sheet at 750-850 DEG C under the action of a protective gas for a third preset time length, to obtain high-silicon high-performance non-oriented electrical steel.

[0041] In view of the influence of the increase of the silicon content on the magnetic properties of the high-silicon non-oriented electrical steel, the preparation method of the high-silicon high-performance non-oriented electrical steel of the embodiment of the application optimizes the texture of the continuous casting billet to improve the magnetic properties of the high-silicon non-oriented electrical steel on the basis of the traditional high-silicon non-oriented electrical steel production process. The rolling angle of the warm rolling plate after normalization and warm rolling, the intermediate annealing treatment after the warm rolling treatment, and the multi-pass cold rolling treatment are controlled, and finally the final annealing treatment is performed on the cold rolling sheet, to produce the high-silicon high-performance non-oriented electrical steel based on the rolling mode. The high-silicon non-oriented electrical steel with high magnetic induction and low iron loss is produced. The vacuum induction smelting means maintaining the vacuum of the smelting furnace, and the air free forging means free forging in an air environment.

[0042] In some embodiments, the molten steel of the non-oriented electrical steel includes the following composition components in mass percentage: C: 0.002wt.%-0.005wt.%, Si: 6.0wt.%-6.5wt.%, Mn: 0.2wt.-0.3wt.%, S<0.005%, and the balance is iron and unavoidable impurities.

[0043] In some embodiments, the size of the continuous casting billet is 120mm in width and 30mm in height.

[0044] In some embodiments, the first preset time length of the heat preservation treatment of the continuous casting billet heated to 1000-1400 DEG C is 30-60 minutes.

[0045] In some embodiments, the continuous casting billet is heated by using a high-temperature resistance heating box-type furnace.

[0046] The inventors of the present application found that when the Si element content of high-silicon non-oriented silicon steel is increased to more than 6.0 wt.%, a DO3 structure phase is formed at low temperature, and when the temperature is increased to more than 550°C, the DO3 is completely transformed into a B2 structure, and when the temperature is continuously increased to more than 750°C, the B2 structure is completely transformed into an A2 structure. Both the DO3 and B2 structure phases are ordered phases, and the matrix is disordered as the temperature increases. The existence of the two ordered phases greatly increases the brittleness of the high-silicon steel, and the solid solution strengthening of Si atoms further increases the hardness, reduces the plasticity and toughness, and makes the rolling processing of the high-silicon steel extremely difficult. However, the problem of difficult rolling processing can be solved by warm rolling treatment. Through the reduction ratio of hot rolling-warm rolling, the directional nucleation of λ texture, {114} <481>, and many other non-gamma oriented grains in the shear band can be promoted, thereby improving the magnetic properties of non-oriented electrical steel.

[0047] It should be noted that the DO structure is an ordered superstructure commonly found in alloys composed of elements such as iron, silicon, aluminum, etc. For high-silicon steel (usually referring to Fe-Si alloy with silicon content of 3.5wt.%~6.5wt.%), its core phase is DO structure based on Fe Si chemical formula, which is an ordered structure composed of four interpenetrating face-centered cubic sublattices: A site: completely occupied by iron atoms; B site: completely occupied by iron atoms (but the environment of these iron atoms is different from that of the A site); C site and D site: randomly occupied by silicon atoms and part of iron atoms (in the ideal Fe Si, C and D sites are orderly occupied by silicon and iron atoms in a 1:1 ratio, but in actual alloys, there may be deviations).

[0048] DO structure and B2 structure: DO structure has a higher degree of order than B2 structure. B2 structure is a simple alternating arrangement of Fe and Si atoms in a body-centered cubic lattice. When the alloy is cooled from a high-temperature disordered body-centered cubic state, B2 ordering occurs first, and DO ordering occurs at a lower temperature. Therefore, DO is a higher-order, lower-temperature ordered phase.

[0049] A2 structure, which has a disordered body-centered cubic structure. All atoms (Fe and Si) randomly occupy the lattice points of the BCC lattice without any specific order. It exists in a high-temperature state (usually > 750°C, the specific temperature depends on the silicon content) In some embodiments, a φ330-350mm double-roller hot rolling mill is used for hot rolling of the heated steel billet; wherein φ330-350mm represents a roller diameter of 330mm-350mm.

[0050] In some embodiments, the heated billet is subjected to a multi-pass hot rolling process.

[0051] In some embodiments, the hot-rolled plate has a thickness of 3.0 mm to 3.4 mm.

[0052] In some embodiments, the second preset duration of the normalizing process is 4 minutes to 12 minutes. Exemplarily, it can be 5, 6, 7, 7.5, 8, 10, 11 minutes.

[0053] The preparation method of the high-silicon high-performance non-oriented electrical steel provided by the embodiments of the present application can homogenize the microstructure and refine the grains of the hot-rolled plate through the normalizing process. During the cold rolling process, the large grain size can form many shear bands. During the final annealing process, new lambda texture and Goss texture grains are nucleated and grown in the shear bands, and the large grain size leads to a reduction in the nucleation sites of gamma grains, i.e., a reduction in grain boundaries. The volume fraction of the final lambda texture and Goss texture increases, while the volume fraction of the gamma texture decreases, thereby improving the magnetic properties of the finished product.

[0054] In some embodiments, the first warm rolling process is performed on the normalized steel material using a four-high cold and warm rolling mill with a roll diameter of φ330-350 mm.

[0055] The preparation method of the high-silicon high-performance non-oriented electrical steel provided by the embodiments of the present application adopts a warm rolling combined with cross-rolling method to prepare the high-silicon high-performance non-oriented electrical steel. The distribution of the texture is directionally regulated by first warm rolling the normalized steel material along the HRD direction and second warm rolling the normalized steel material along the HTD direction, thereby optimizing the magnetic properties of the high-silicon high-performance non-oriented silicon steel. When the normalized steel material is subjected to the warm rolling process, the first warm rolling process is performed on the normalized steel material at a temperature of 600-700°C and a reduction of 75%-80%, which can promote the directional nucleation of the lambda texture, {114}<481>, and many other non-gamma oriented grains in the shear bands. Then, the first warm rolled billet is subjected to the second warm rolling process using the HTD sampling direction at a temperature of 400-500°C and a reduction of 45%-50%, so as to directionally regulate the texture of the first warm rolled billet and optimize the magnetic properties of the high-silicon high-performance non-oriented electrical steel.

[0056] In the cross-rolling process, the first warm rolled billet is subjected to a normal direction rolling process (i.e., CRD) or a 90° rotation direction rolling process (i.e., CTD) based on the 90° rotated warm rolled plate.

[0057] The preparation method of the high-silicon high-performance non-oriented electrical steel provided by the embodiments of the present application performs intermediate annealing treatment on the warm-rolled plate at 900-1000 DEG C, so as to eliminate internal stress and crystal defects generated by warm rolling through recrystallization process, soften the warm-rolled plate and restore plasticity, facilitate subsequent cold rolling or further warm rolling processing, avoid cold rolling cracking or excessive load of rolling mill caused by excessive hardening, and thus optimize the magnetic properties of the final product of the high-silicon high-performance non-oriented electrical steel. It should be noted that the intermediate annealing treatment is performed on the first warm-rolled steel billet and the steel billet obtained by the second warm rolling, both after the corresponding warm rolling treatment.

[0058] In some embodiments, the third preset length of the intermediate annealing treatment is 8-10 minutes. For example, it can be 8, 9 or 10 minutes.

[0059] In some embodiments, the cold-rolled thin plate is obtained by using a Φ120*350mm four-roll cold and warm rolling mill. It should be noted that Φ120*350mm represents that the roll diameter is 120-350mm.

[0060] In some embodiments, the thickness of the cold-rolled thin plate is 0.25-0.35mm.

[0061] In some embodiments, the cold-rolled thin plate is subjected to final annealing and holding treatment by using a silicon steel high-temperature annealing furnace. The holding is performed by using an electric heating method.

[0062] In some embodiments, the fourth preset length is 35-45 minutes.

[0063] In some embodiments, the protective gas is an inert gas.

[0064] In some embodiments, the protective gas includes at least one of He, Ar and N2.

[0065] In the second aspect, the embodiments of the present application provide a high-silicon high-performance non-oriented electrical steel, which is prepared according to the preparation method of the high-silicon high-performance non-oriented electrical steel provided in the above-mentioned first aspect.

[0066] In some embodiments, the high-silicon high-performance non-oriented electrical steel includes the following textures: Goss texture, content 17.1%-19.5%; lambda texture, content 15.7%-17.2%; gamma texture 27.3%-28.1%. It should be noted that the above-mentioned textures are the main textures in the high-silicon high-performance non-oriented electrical steel, and the proportions of the remaining textures are small and have little effect on the performance of the high-silicon high-performance electrical steel, so they are not given one by one.

[0067] In some embodiments, the magnetic properties of the high-silicon high-performance non-oriented electrical steel are as follows: P 0.0005-0.0015 at low frequency; P 0.0005-0.0015 at high frequency; and B 1.65-1.75 T.15 / 50 2.39W / Kg~2.5W / Kg, P 10 / 400 13.51W / Kg~14.90W / Kg, B 50 1.50T~1.55T.

[0068] The following specific examples and comparative examples are compared to further clarify the technical solutions adopted by the present application and their beneficial effects. The composition and weight percentage content of the non-oriented electrical steel used in the following examples and comparative examples are shown in Table 1 below.

[0069] Table 1 The process route adopted in the following Examples 1-4 is: smelting-forging-hot rolling-warm rolling-intermediate annealing-normalizing-cold rolling-final annealing.

[0070] Example 1 The present embodiment provides a preparation method of high-silicon high-performance non-oriented electrical steel, comprising: providing a molten steel of non-oriented electrical steel as shown in Table 1; vacuum induction smelting the molten steel of non-oriented electrical steel, and heat treatment at 1090℃~1020℃, using air free forging into a continuous casting billet with a width of 120mm and a height of 30mm; using a high-temperature resistance heating box furnace to heat treat the continuous casting billet, heating the continuous casting billet to 1190℃~1220℃, and heat preservation for a first preset time, i.e. 30 minutes, to obtain a heated billet; using a double-roller hot rolling mill with a roller diameter of φ330mm to perform 5-pass hot rolling on the heated billet to obtain a hot-rolled plate, the thickness of the hot-rolled plate being 3.38mm; firstly normalizing the 3.38mm-thick hot-rolled plate by a normalizing process of 950℃x6min to obtain a normalized steel material; then warm rolling the normalized steel material at 650℃, including: using a four-roller cold warm rolling mill with a roller diameter and length of φ330mmx350mm to perform warm rolling on the normalized steel material, as shown in Table 2, including: performing first warm rolling on the hot-rolled plate at 650℃ and a reduction of 78% along the HRD direction to obtain a first warm-rolled billet; then performing first intermediate annealing at an annealing temperature of 950℃ for 10 minutes to obtain a first intermediate annealed billet; after the first intermediate annealing, performing second warm rolling on the first intermediate annealed billet using the HTD direction, the warm rolling temperature being 450℃ and the reduction being 46%, to obtain a second warm-rolled billet; then performing second intermediate annealing on the second warm-rolled billet at an annealing temperature of 950℃ for 10 minutes to obtain a second intermediate annealed billet. As shown in Table 2, the thickness of the first warm-rolled billet is 3.38mm, the thickness of the first intermediate annealed billet is 3.38mm, the thickness of the second warm-rolled billet is 3.38mm, and the thickness of the second intermediate annealed billet is 3.38mm. Figure 3 ​Figure 4 As shown, the second intermediate annealed steel blank is then subjected to 6-pass cold rolling processing in the CTD direction at 400-500°C and a reduction of 45%, to obtain a cold-rolled sheet having a thickness of 0.35 mm, and the cold-rolled sheet is obtained; The cold-rolled sheet is subjected to a final annealing treatment at 800°C under Ar gas protection for 40 minutes, to obtain the high-silicon high-performance non-oriented electrical steel 1.

[0071] Example 2 This example provides a method for preparing a high-silicon high-performance non-oriented electrical steel, which differs from Example 1 in that: Figure 4 As shown, the second intermediate annealed steel blank is subjected to 6-pass cold rolling processing in the CTD direction, to finally obtain the high-silicon high-performance non-oriented electrical steel 2.

[0072] Example 3 This example provides a method for preparing a high-silicon high-performance non-oriented electrical steel, which differs from Example 1 in that: Figure 4 As shown, the second intermediate annealed steel blank is subjected to 1-pass cold rolling processing in the CRD direction, and is subjected to 1-pass CRD cold rolling processing, to finally obtain the high-silicon high-performance non-oriented electrical steel 3.

[0073] Example 4 This example provides a method for preparing a high-silicon high-performance non-oriented electrical steel, which differs from Example 1 in that: Figure 4 As shown, the second intermediate annealed steel blank is subjected to 6-pass cold rolling processing in the CTD direction, to finally obtain the high-silicon high-performance non-oriented electrical steel 4.

[0074] Example 5 This example provides a method for preparing a high-silicon high-performance non-oriented electrical steel, which differs from Example 1 in that a four-high cold-temperature rolling mill having a roll diameter and roll length of φ330mm x 350mm is used to perform warm rolling processing on the normalized steel material, including: performing first warm rolling processing on the normalized steel material at 680°C and a reduction of 80%, to obtain a first warm-rolled steel blank; then performing first intermediate annealing processing at an annealing temperature of 980°C and a holding time of 10 minutes, to obtain a first intermediate annealed steel blank; after the first intermediate annealing processing is completed, performing second warm rolling processing on the first intermediate annealed steel blank in the HTD direction at a warm rolling temperature of 500°C and a reduction of 48%, to obtain a second warm-rolled steel blank; then performing second intermediate annealing on the second warm-rolled steel blank at an annealing temperature of 930°C and a holding time of 10 minutes, to obtain a second intermediate annealed steel blank. Reference Figure 4As shown, the second intermediate annealed steel blank is then subjected to 6-pass cold rolling in the HRD direction at a temperature of 400-500°C and a reduction of 45-50% to obtain a cold-rolled sheet having a thickness of 0.35 mm. The cold-rolled sheet is subjected to a final annealing treatment at 800°C for 40 minutes under Ar gas protection to obtain high-silicon high-performance non-oriented electrical steel 5.

[0075] Example 6 Example 6 provides a method for preparing high-silicon high-performance non-oriented electrical steel, which differs from Example 1 in that a four-high cold-temperature rolling mill having a roll diameter and length of φ330 mm x 350 mm is used for warm rolling of the normalized steel material, including: subjecting the normalized steel material to a first warm rolling treatment at 620°C and a reduction of 75% to obtain a first warm-rolled steel blank; then performing a first intermediate annealing treatment at an annealing temperature of 900°C for 10 minutes to obtain a first intermediate annealed steel blank; after the first intermediate annealing treatment, subjecting the first intermediate annealed steel blank to a second warm rolling treatment in the HTD direction at a warm rolling temperature of 425°C and a reduction of 50% to obtain a second warm-rolled steel blank; then performing a second intermediate annealing treatment on the second warm-rolled steel blank at an annealing temperature of 930°C for 10 minutes to obtain a second intermediate annealed steel blank. Figure 4 As shown, the second intermediate annealed steel blank is then subjected to 6-pass cold rolling in the HRD direction at a temperature of 400-500°C and a reduction of 45-50% to obtain a cold-rolled sheet having a thickness of 0.35 mm. The cold-rolled sheet is subjected to a final annealing treatment at 800°C for 40 minutes under Ar gas protection to obtain high-silicon high-performance non-oriented electrical steel 5.

[0076] Comparative Example 1 Comparative Example 1 provides a method for preparing high-silicon high-performance non-oriented electrical steel, which differs from Example 1 in that Figure 2 As shown, the first warm-rolled steel blank after the first intermediate annealing treatment is subjected to a second warm rolling treatment in the HRD direction, and Figure 4 As shown, the second intermediate annealed steel blank is subjected to 6-pass cold rolling in the CRD direction to obtain non-oriented electrical steel 0.

[0077] The magnetic properties of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 and Examples 1-6 are measured, and the results are summarized in Table 2 below. The sample size for the magnetic property measurement is 50 mm x 50 mm non-oriented silicon steel, and the equipment used is TD8510 for measuring the magnetic properties of silicon single sheets. The performance indicators measured include magnetic induction B 50 (5000 A / m magnetic field), low-frequency iron loss P 1.5 / 50(50 Hz frequency, 1.5 T magnetic induction) and high frequency core loss P 1.0 / 400 (400 Hz frequency, 1.0 T magnetic induction), two sets of data in RD and TD directions were measured, and the average value was finally taken.

[0078] Table 2 As Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 shown, in each figure, the left side graph is the Oim graph of the high-silicon high-performance non-oriented electrical steel after final annealing treatment, which is the distribution graph of texture; the right side graph is the ODF graph of the non-oriented electrical steel after final annealing treatment. Among them, the ODF graph is a kind of graph for three-dimensional, quantitative description of the distribution of all grain orientations in the material. The two axes in the graph represent different rotation angles (Euler angles) of the grains in three-dimensional space. Each point on the graph corresponds to a specific crystal orientation, and the color represents the aggregation degree of the grains with the orientation in the material, that is, the texture intensity. The warmer the color, the more grains of the orientation, and the stronger the texture; the cooler the color, the fewer grains of the orientation. The grain orientations beneficial to magnetic properties are cubic texture and Goss texture. The two graphs can see the structure and texture of the five process finished plates, the introduction of cross-rolling and the change of reduction have obvious influence on the texture. The ODF graph shows that the texture of the process finished plate without introducing cross-rolling is composed of γ texture and weak Goss texture, and the λ texture is very weak.

[0079] As Figure 5 shown, (a) is the Oim graph of the high-silicon high-performance non-oriented electrical steel of the comparative example 1 after final annealing treatment, that is, the distribution graph of texture; (b) is the ODF graph of the high-silicon high-performance non-oriented electrical steel of the comparative example 1 after final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of the comparative example 1 is 0.72.

[0080] As Figure 6 shown, (c) is the Oim graph of the high-silicon high-performance non-oriented electrical steel of the example 1 after final annealing treatment, that is, the distribution graph of texture; (d) is the ODF graph of the high-silicon high-performance non-oriented electrical steel of the example 1 after final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of the example 1 is 0.92.

[0081] As Figure 7As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75.

[0082] As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75. Figure 8 As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75.

[0083] As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75. Figure 9 As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75.

[0084] As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75. Figure 6 As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75. Figure 7 As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75. Figure 8 As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75. Figure 9 As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75.

[0085] As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75.

[0086] As shown in (e), the Oim diagram, i.e. the distribution diagram of texture, of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 after the final annealing treatment; (f) is the ODF diagram of the high-silicon high-performance non-oriented electrical steel of Example 2 after the final annealing treatment; in the figure, the texture factor of the high-silicon high-performance non-oriented electrical steel of Example 2 is 0.75. Figure 10As shown, it is a comparison chart of magnetic property data of the high-silicon high-performance non-oriented electrical steel finished plate. The magnetic induction intensity of the high-silicon high-performance non-oriented electrical steel of Comparative Example 1 and Example 3 is the lowest, corresponding to the lower texture factor values of the two processes; while the magnetic induction intensity of Examples 1, 2 and 4 is higher, also corresponding to the higher texture factor values of the three, indicating that the texture factor has a good corresponding relationship with the magnetic induction intensity. At the same time, the main influencing factors of the silicon steel loss are the plate thickness and the grain size, the plate thickness mainly affects the eddy current loss, and under high frequency conditions, the eddy current loss occupies a dominant position, so the high-frequency iron loss of the 0.35 mm thick high-silicon high-performance non-oriented electrical steel finished plate of Example 1 and Example 2 is higher than that of the 0.30 mm thick high-silicon high-performance non-oriented electrical steel finished plate of Example 3 and Example 4, and the low-frequency and high-frequency iron loss of Example 1 is lower than that of Example 2 because the grain size of Example 1 is larger, resulting in a decrease in the domain wall area and the crystal defects at the grain boundary, thereby reducing the hysteresis loss.

[0087] The above is only a specific embodiment of the present application, and those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process described above can refer to the corresponding process in the foregoing method embodiment, which will not be described here. It should be understood that the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be covered within the protection scope of the present application.

Claims

1. A method for preparing high-silicon, high-performance non-oriented electrical steel, characterized in that, include: Molten steel for non-oriented electrical steel; The molten steel of the non-oriented electrical steel is subjected to vacuum induction smelting and held at 1000℃~1200℃, and then air-free forging is used to form a continuous casting billet. The continuously cast steel billet is heated to 1000℃~1400℃ and held at that temperature for a first preset time to obtain a heated steel billet. Heated steel billets are hot-rolled to obtain hot-rolled plates; Hot-rolled steel plates are normalized at 850℃~1050℃ for a second preset time to obtain normalized steel. The process of performing warm rolling on normalized steel includes: performing a first warm rolling treatment on normalized steel at 600℃~700℃ and a reduction of 75%~80%, with the sampling direction being HRD, to obtain a first warm-rolled steel billet; performing a second warm rolling treatment on the first warm-rolled steel billet at 400℃~500℃ and a reduction of 45%~50%, with the sampling direction being HTD; and, during the warm rolling process, performing an intermediate annealing treatment on the warm-rolled plate at 900℃~1000℃ for a third preset time, followed by cooling after annealing to obtain a cooled warm-rolled plate. The cooled warm-rolled sheet is subjected to multiple cold rolling processes using CTD and / or CRD sampling directions to obtain cold-rolled thin sheet; Cold-rolled sheets are subjected to a final annealing treatment at 750℃~850℃ under the action of a protective gas for a fourth preset time to obtain high-silicon, high-performance non-oriented electrical steel.

2. The method for preparing high-silicon, high-performance non-oriented electrical steel according to claim 1, characterized in that, The molten steel of the non-oriented electrical steel comprises the following components by mass percentage: C: 0.002wt.%~0.005wt.%, Si: 6.0wt.%~6.5wt.%, Mn: 0.2wt.%~0.3wt.%, S<0.005%, with the balance being iron and unavoidable impurities; Optionally, the dimensions of the continuously cast steel billet are 120 mm in width and 30 mm in height.

3. The method for preparing high-silicon, high-performance non-oriented electrical steel according to claim 1, characterized in that, The first preset duration is 30 to 60 minutes; Optionally, the continuously cast steel billet is heated using a high-temperature resistance heating box furnace.

4. The method for preparing high-silicon, high-performance non-oriented electrical steel according to claim 1, characterized in that, The heated steel billet is hot-rolled using a φ330~350mm twin-roll hot rolling mill; where φ330~350mm indicates that the roll diameter is 330mm~350mm. Optionally, the heated steel billet is subjected to multi-pass hot rolling. Optionally, the thickness of the hot-rolled plate is 3.0 mm to 3.4 mm.

5. The method for preparing high-silicon, high-performance non-oriented electrical steel according to claim 1, characterized in that, The normalized steel is subjected to a first warm rolling treatment using a four-roll cold and warm rolling mill with a diameter of φ330~350mm, where φ330~350mm indicates that the roll diameter is 330mm~350mm.

6. The method for preparing high-silicon, high-performance non-oriented electrical steel according to claim 1, characterized in that, The second preset duration for the normalization process is 4 to 12 minutes; Optionally, the third preset duration for the intermediate annealing process is 8 to 10 minutes.

7. The method for preparing high-silicon, high-performance non-oriented electrical steel according to claim 1, characterized in that, The cooled warm-rolled plate was cold-rolled using a Φ120×350mm four-roll cold-warm rolling mill. Optionally, the thickness of the cold-rolled sheet is 0.25 mm to 0.35 mm.

8. The method for preparing high-silicon, high-performance non-oriented electrical steel according to claim 1, characterized in that, The cold-rolled sheet was subjected to final annealing and heat preservation treatment using a silicon steel high-temperature annealing furnace. Optionally, the fourth preset duration is 35 minutes to 45 minutes; Optionally, the protective gas is an inert gas; Optionally, the protective gas includes at least one of He, Ar, and N2.

9. A high-silicon, high-performance non-oriented electrical steel, characterized in that, The high-silicon, high-performance non-oriented electrical steel is prepared according to any one of claims 1-8.

10. The high-silicon, high-performance non-oriented electrical steel according to claim 9, characterized in that, The textures include: Goss texture, with a content of 17.1%–19.5%; λ texture, with a content of 15.7%–17.2%; and γ texture, with a content of 27.3%–28.1%.

11. The high-silicon, high-performance non-oriented electrical steel according to claim 9, characterized in that, The magnetic properties of the high-silicon, high-performance non-oriented electrical steel are as follows: at low frequencies, P15 / 50 is 2.39 W / Kg to 2.5 W / Kg; at medium and high frequencies, P10 / 400 is 13.51 W / Kg to 14.90 W / Kg; and B50 is 1.50 T to 1.55 T.

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