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CN-121992276-A - High-millability production method of series high-grade non-oriented silicon steel

CN121992276ACN 121992276 ACN121992276 ACN 121992276ACN-121992276-A

Abstract

The application discloses a high-rollability production method of a series of high-grade non-oriented silicon steel. The production method comprises the steps of continuous casting, heating, rough rolling and finish rolling a continuous casting blank to obtain a hot rolled plate with the thickness of 2.3-3.5 mm, carrying out pickling and continuous cold rolling on the hot rolled plate without frequent treatment in a multi-frame acid continuous rolling unit, obtaining a hard rolled plate with the thickness of 0.4-1.2 mm, controlling the roll bending force of a working roll of the multi-frame acid continuous rolling unit within the range of 50 kN-150 kN, enabling the edge of the hard rolled plate to generate controllable edge waves with the height of 1.0-3.0 mm, carrying out 2-4-pass finish cold rolling on the steel plate by adopting a single-frame rolling machine, carrying out total reduction of 40-65%, obtaining a finish cold rolled plate with the thickness of (0.15-0.50) +/-0.003 mm, and annealing to obtain a finished non-oriented silicon steel product.

Inventors

  • YUE ZHONGXIANG
  • CHEN GANG
  • YANG JIAWEI
  • Zhu henan
  • WU SHENGJIE
  • MA HAN

Assignees

  • 张家港扬子江冷轧板有限公司
  • 江苏省沙钢钢铁研究院有限公司
  • 江苏沙钢钢铁有限公司
  • 江苏沙钢集团有限公司

Dates

Publication Date
20260508
Application Date
20260226

Claims (20)

  1. 1. A method for producing unoriented silicon steel, characterized in that the production method comprises the following steps in sequence, The continuous casting process comprises the steps of obtaining a continuous casting blank, wherein the chemical components of the continuous casting blank comprise, by mass, less than or equal to 0.005% of C, 1.5-4.5% of Si, 0.2-1.5% of Mn, less than or equal to 1.5% of Al, less than or equal to 0.01% of S, less than or equal to 0.08% of P, less than or equal to 0.01% of N, less than or equal to 0.01% of O, less than or equal to 5.0% of Cr, ni and Cu respectively, less than or equal to 0.1% of Mo, nb, V, ti% of Fe and unavoidable impurities; a hot rolling procedure, namely heating, rough rolling and finish rolling the continuous casting billet to obtain a hot rolled plate with the thickness of 2.3-3.5 mm; Acid continuous rolling, namely, the hot rolled plate is not subjected to frequent treatment and enters a multi-frame acid continuous rolling unit to be subjected to pickling and continuous cold rolling, the reduction rate of the first-pass cold rolling is 20-30%, the reduction is less than or equal to 0.70mm, and a hard rolled plate with the thickness of 0.4-1.2 mm is obtained; Normalizing the hard rolling plate in a normalizing furnace; a single-frame finish cold rolling procedure, namely adopting a single-frame rolling mill to perform 2-4 times of finish cold rolling on the normalized steel plate, wherein the total reduction rate is 40-65%, and obtaining a finish cold-rolled plate with the thickness of (0.15-0.50) +/-0.003 mm; and annealing the refined cold-rolled plate in an annealing furnace to obtain a non-oriented silicon steel finished product.
  2. 2. The production method of the non-oriented silicon steel according to claim 1, wherein the chemical components of the continuous casting blank comprise, by mass, 0.30-1.5% of Al and 1.7-4.8% of Si+Al, or less than or equal to 0.0030%; And/or the chemical components of the continuous casting blank further comprise one or two of 0.01-0.15% of Sn and 0.01-0.15% of Sb by mass percent.
  3. 3. The method of producing a non-oriented silicon steel according to claim 1, wherein in the hot rolling step, a start rolling temperature of the first pass finish rolling is not less than 950 ℃ and a finish rolling temperature of the last pass finish rolling is (830 to 880) + -15 ℃.
  4. 4. The method of producing a non-oriented silicon steel according to claim 3, wherein the total rolling reduction of finish rolling is 90 to 96% and the rolling reduction of finish rolling in the last pass is 20 to 25%.
  5. 5. A method of producing unoriented silicon steel according to claim 3, characterized by the hot rolling process: When the continuous casting billet enters the heating furnace, the temperature is more than or equal to 350 ℃ and the soaking temperature is 1080-1150 ℃, when the temperature of the continuous casting billet is 350-800 ℃, the heating rate is controlled to be 5-15 ℃ per minute, and when the temperature of the continuous casting billet is 800-1150 ℃, the heating rate is controlled to be more than or equal to 15 ℃ per minute.
  6. 6. The method of producing a non-oriented silicon steel according to claim 3, wherein the hot rolling step is performed by coiling after finish rolling, and the coiling temperature is 600 to 650.+ -. 15 ℃.
  7. 7. The method for producing non-oriented silicon steel according to claim 1, wherein the acid continuous rolling step is performed at a reduction rate of 15-25% in the last-pass cold rolling.
  8. 8. The method for producing non-oriented silicon steel according to claim 1, wherein the acid continuous rolling process comprises: The roughness of working rolls of a first frame and a second frame of the multi-frame acid continuous rolling unit is 1.00+/-0.20 mu m, the chamfering depth of the working rolls corresponding to the edge positions of strip steel is 30-60 mu m, the chamfering insertion amount is 70-100 mm, the roughness of the working rolls of a third frame to a fifth frame is 0.50+/-0.10 mu m, the chamfering depth of the working rolls corresponding to the edge positions of strip steel is 10-15 mu m, and the chamfering insertion amount is 200-300 mm.
  9. 9. The method for producing non-oriented silicon steel according to claim 1, wherein the hard sheet rolling and normalizing step is performed by normalizing the hard sheet to completely recrystallize the structure, and normalizing the structure at a normalizing temperature of 850-1000 + -10 ℃ for 60-100 s.
  10. 10. The method for producing non-oriented silicon steel according to claim 9, wherein the roll hardening normalizing process: The chemical components of the continuous casting blank in percentage by mass meet the condition that Si+Al is more than or equal to 3.0%, and the normalizing temperature is (850-950) +/-10 ℃; Or the chemical components of the continuous casting blank in percentage by mass satisfy 2.0 percent < Si+Al <3.0 percent, and the normalizing temperature is (900-980) +/-10 ℃; or the chemical components of the continuous casting blank in percentage by mass satisfy that Si+Al is less than or equal to 2.0 percent, and the normalizing temperature is (950-1000) +/-10 ℃.
  11. 11. The method for producing non-oriented silicon steel according to claim 9, wherein the normalizing step of the hard rolled sheet is performed by temperature-controlled cooling, wherein the cooling rate is 10-15 ℃ per second when the surface temperature of the steel sheet is not less than 400 ℃ and is 15-20 ℃ per second when the surface temperature of the steel sheet is less than 400 ℃.
  12. 12. The method for producing non-oriented silicon steel according to claim 1, wherein the normalizing step of the hard rolled plate comprises normalizing the hard rolled plate in a weak reducing atmosphere with a volume ratio of H 2 of 15-25% in a mixed atmosphere of H 2 and N 2 , wherein the tension in the normalizing furnace is 8-10N/mm 2 .
  13. 13. The method for producing non-oriented silicon steel according to claim 1, wherein the single-stand finish cold rolling step is a finish cold rolling step performed without preheating, and the first-pass finish cold rolling has a rolling reduction of 30 mm or more and a rolling reduction of 0.40mm or less.
  14. 14. The method for producing non-oriented silicon steel according to claim 1, wherein the single-stand finish cold rolling process comprises: The single-stand rolling mill is a six-roller single-stand cold mill or a twenty-roller single-stand cold mill; The diameter of a working roll of the twenty-roller single-stand cold-rolling mill is 45-65 mm, the roughness of the working roll for the first pass finish cold-rolling is 2.50+/-0.5 mu m, and the roughness of the working roll for the final pass finish cold-rolling is 0.50+/-0.10 mu m.
  15. 15. The method for producing non-oriented silicon steel according to claim 1, wherein the annealing step is to anneal the fine cold-rolled sheet in an annealing furnace to completely recrystallize the structure, the annealing temperature is 850-1050 ℃ and the annealing time is 100-120 s.
  16. 16. The method for producing non-oriented silicon steel according to claim 15, wherein the annealing step is performed with the tension in the annealing furnace controlled to be 1-3N/mm 2 .
  17. 17. The method for producing non-oriented silicon steel according to claim 15, wherein the annealing step comprises: And after the annealing time is up, performing temperature control cooling, wherein the cooling speed is 5-10 ℃ per second when the surface temperature of the steel plate is more than 700 ℃, the cooling speed is 10-15 ℃ per second when the surface temperature of the steel plate is 400-700 ℃, and the cooling speed is 15-20 ℃ per second when the surface temperature of the steel plate is less than 400 ℃.
  18. 18. The method for producing non-oriented silicon steel according to claim 15, wherein the annealing temperature is T t1 ±10℃;T t1 , which has a unit of °c and is represented by the formula 900+200 (11 Si-14mn+21al), wherein the element symbols in the formula represent the mass percentages of the corresponding elements in the continuous casting slab.
  19. 19. The method for producing non-oriented silicon steel according to claim 1, wherein the continuous casting process is characterized in that the thickness of a continuous casting blank is 200-250 mm, the equiaxial crystal rate is more than or equal to 65%, and the concave depth of a narrow section is less than or equal to 3mm.
  20. 20. The method for producing non-oriented silicon steel according to claim 1, wherein the drawing speed is controlled to be 0.80-1.10 m/min in the continuous casting process.

Description

High-millability production method of series high-grade non-oriented silicon steel Technical Field The application belongs to the technical field of steel material preparation, and relates to a high-rollability production method of a series of high-grade non-oriented silicon steel. Background The non-oriented silicon steel is a core functional material for manufacturing motor iron cores and transformer iron cores, and the iron loss and magnetic induction level of the non-oriented silicon steel directly determine the energy efficiency grade of an electric product. Along with the acceleration of the carbon neutralization process and the continuous upgrading of the motor energy efficiency standard in the global industrial field, the market demand of high-grade non-oriented silicon steel is rapidly increased, and meanwhile, higher requirements on magnetic performance and production efficiency are provided. A typical production process of the high-grade non-oriented silicon steel comprises hot rolling, normalizing, pickling, cold rolling, annealing of finished products and coating. In order to obtain lower iron loss, the component design needs to be added with higher content of Si and Al so as to improve the resistivity and reduce the eddy current loss. However, si and Al are both ferrite stabilizing elements, and an increase in the content thereof brings about the following prominent problems: (1) The hot rolling process is completed in a ferrite region, the rolled structure is a deformed fiber structure, dynamic recrystallization is difficult to occur, and the plasticity of the hot rolled plate is obviously reduced; (2) In order to improve the magnetic performance, the traditional process needs to carry out normalizing treatment on the hot rolled plate before cold rolling to lead the fiber structure to be recrystallized and the crystal grains to be coarsened, but the normalizing treatment further reduces the plasticity of the hot rolled plate; (3) In the cold rolling process of the low-plasticity hot-rolled normalized plate, the deformation of the plate in the thickness direction is inconsistent, the surface layer extends more than the central layer, so that the central layer generates tensile stress to induce microcracks, the microcracks are expanded to the edge to form edge cracks, and the strip breakage occurs when the crack is serious. The problems restrict the production efficiency and the cost of high-grade unoriented silicon steel for a long time. The prior art mainly seeks solutions from the following paths that firstly, the upper limit of total Si+Al is limited, part of magnetic performance is sacrificed to replace rollability, which leads to the inability to meet the requirement of higher energy efficiency level, secondly, the thickness of a hot rolled plate is reduced, so that the total deformation of the cold rolled plate is reduced, deformation is relieved, but the method greatly increases the hot rolling load, brings strict requirements on the capacity of a hot rolling production line, the temperature drop after the thickness reduction of the hot rolled plate is accelerated, the plate shape control difficulty is increased, thirdly, preheating before cold rolling is carried out, so as to improve plasticity, but preheating equipment and energy media are needed to be additionally arranged, the investment cost and the running cost are increased, and the problem of cold rolling and strip breakage of high Si+Al mark cannot be fundamentally solved. In summary, the existing high-grade non-oriented silicon steel production method has the inherent contradiction that the improvement of magnetic property and the guarantee of cold rolling property are difficult to achieve, and the pursuit of production efficiency (continuous production of acid continuous rolling) and adaptation to high-grade characteristics (low plasticity) are mutually conflicting. Disclosure of Invention In order to solve the technical problems, the application aims to provide a high-rollability production method of a series of high-grade non-oriented silicon steel. In order to achieve the above-mentioned purpose, an embodiment of the present application provides a method for producing unoriented silicon steel. The production method comprises the steps of sequentially carrying out the steps, The continuous casting process comprises the steps of obtaining a continuous casting blank, wherein the chemical components of the continuous casting blank comprise, by mass, less than or equal to 0.005% of C, 1.5-4.5% of Si, 0.2-1.5% of Mn, less than or equal to 1.5% of Al, less than or equal to 0.01% of S, less than or equal to 0.08% of P, less than or equal to 0.01% of N, less than or equal to 0.01% of O, less than or equal to 5.0% of Cr, ni and Cu respectively, less than or equal to 0.1% of Mo, nb, V, ti% of Fe and unavoidable impurities; a hot rolling procedure, namely heating, rough rolling and finish rolling the continuous casting billet to obtai