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CN-121976008-A - Production method of high-grade unoriented silicon steel with cold rolling smooth operation and dimensional precision

CN121976008ACN 121976008 ACN121976008 ACN 121976008ACN-121976008-A

Abstract

The application discloses a production method of high-grade unoriented silicon steel with both cold rolling smooth operation and dimensional accuracy. The non-oriented silicon steel has a thickness of 0.05-0.50 mm, longitudinal thickness fluctuation of less than or equal to +/-3 mu m and/or transverse thickness difference of less than or equal to 5 mu m, and the production method comprises sequentially heating, hot rolling, coiling, acid continuous rolling, hard plate normalizing, single-stand finish rolling and annealing, wherein the acid continuous rolling comprises a rolling reduction rate of 20-30 ℃ of first-pass cold rolling, a rolling reduction rate of less than or equal to 0.70mm, the hard plate normalizing comprises a normalizing temperature (850-1000) +/-10 ℃ and a normalizing time period of 60-100 s, the single-stand finish rolling comprises 2-4 passes, the total rolling reduction rate is 40-80%, the rolling reduction rate of the first-pass finish rolling is more than or equal to 30%, the rolling reduction rate of less than or equal to 0.40mm, the rolling force of each pass finish rolling is less than or equal to 6000kN, the annealing comprises an annealing temperature of 850-1050 ℃ and an annealing time period of 40-120 s, and then cooling is controlled in a sectional manner.

Inventors

  • YUE ZHONGXIANG
  • MA HAN
  • HU XIANJUN
  • CHEN GANG
  • WU SHENGJIE
  • SHI YIXIN

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
20260505
Application Date
20260226

Claims (18)

  1. 1. A production method of high-grade non-oriented silicon steel is characterized in that the non-oriented silicon steel is a steel plate with the thickness of 0.05-0.50 mm, longitudinal thickness fluctuation is less than or equal to +/-3 mu m and/or transverse thickness difference is less than or equal to 5 mu m, and the production method comprises a heating process, a hot rolling process, a coiling process, an acid continuous rolling process, a hard rolling plate normalizing process, a single-frame finish cold rolling process and an annealing process in sequence, wherein: An acid continuous rolling procedure, namely the reduction rate of the first-pass cold rolling is 20-30%, and the reduction rate is less than or equal to 0.70mm; Normalizing the obtained hard rolled plate at 850-1000+/-10 ℃ for 60-100 s; A single-frame finish cold rolling procedure, namely 2-4 passes of finish cold rolling are carried out, the total rolling reduction is 40-80%, the rolling reduction of the first pass of finish cold rolling is more than or equal to 30%, the rolling reduction is less than or equal to 0.40mm, and the rolling force of each pass of finish cold rolling is less than or equal to 6000kN; And the annealing process comprises the steps of carrying out sectional control cooling after the annealing temperature is 850-1050 ℃ and the annealing time is 40-120 s.
  2. 2. The method for producing high-grade unoriented silicon steel according to claim 1, characterized in that the sectional control cooling comprises a cooling rate of 5 to 10 ℃ per second at a steel plate surface temperature of >700 ℃, a cooling rate of 10 to 15 ℃ per second at a steel plate surface temperature of 400 to 700 ℃, and a cooling rate of 15 to 20 ℃ per second at a steel plate surface temperature of <400 ℃.
  3. 3. The method for producing high-grade unoriented silicon steel according to claim 1, characterized in that the single-stand finish cold rolling process uses a single-stand cold rolling mill in which working rolls are flat rolls and intermediate rolls have a single-side taper of 0.20 to 0.30%.
  4. 4. The method for producing high-grade unoriented silicon steel according to claim 1 or 3, characterized in that in the single-stand finish cold rolling step, the intermediate rolls of the single-stand cold rolling mill used in the finish cold rolling are driven to axially shift.
  5. 5. The production method of the high-grade unoriented silicon steel according to claim 1 is characterized in that in the acid continuous rolling process, in a multi-frame acid continuous rolling unit, the chamfering depth of the working rolls of a first frame and a second frame is 30-60 mu m and the chamfering insertion amount is 70-100 mm corresponding to the edge position of strip steel, and the chamfering depth of the working rolls of a third frame to a fifth frame is 10-15 mu m and the chamfering insertion amount is 200-300 mm corresponding to the edge position of strip steel.
  6. 6. The method for producing high-grade unoriented silicon steel according to claim 5, characterized in that the acid tandem rolling step is performed by using any one of a six-roller five-frame acid tandem rolling unit, a six-roller six-frame acid tandem rolling unit and an eighteen-roller six-frame acid tandem rolling unit as the multi-frame acid tandem rolling unit.
  7. 7. The method for producing high-grade unoriented silicon steel according to claim 6, characterized in that the acid continuous rolling process comprises the step of using a six-roller five-frame acid continuous rolling machine set, wherein the working roller diameter is 300-500 mm, the working roller roughness of a first frame and a second frame of the six-roller five-frame acid continuous rolling machine set is 1.00+/-0.20 mu m, and the working roller roughness of a third frame to a fifth frame is 0.50+/-0.10 mu m.
  8. 8. The method for producing high-grade unoriented silicon steel according to claim 1, characterized in that the acid continuous rolling process comprises the step of controlling the bending force of the working rolls of a multi-frame acid continuous rolling unit within the range of 50kN to 150kN, so that the edge of the obtained rolled hard plate generates controllable edge waves with the height of 1.0-3.0 mm.
  9. 9. The method for producing high-grade unoriented silicon steel according to claim 1, characterized in that the single-stand precision cold rolling step uses a six-roll single-stand cold rolling mill or a twenty-roll single-stand cold rolling 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.
  10. 10. The method for producing high-grade unoriented silicon steel according to claim 1, characterized in that the normalizing step of the hard sheet is performed in a normalizing furnace, and the tension in the normalizing furnace is 8 to 10N/mm 2 .
  11. 11. The method for producing high-grade unoriented silicon steel according to claim 1, characterized in that the normalizing process of the rolled hard sheet is performed with temperature-controlled cooling, the cooling rate is 10-15 ℃ per second when the surface temperature of the steel sheet is more than or equal to 400 ℃, and the cooling rate is 15-20 ℃ per second when the surface temperature of the steel sheet is less than 400 ℃.
  12. 12. The method for producing high-grade unoriented silicon steel according to claim 1, characterized in that the annealing step is performed in an annealing furnace, and the tension in the annealing furnace is controlled to be 1-3N/mm 2 .
  13. 13. The method for producing high-grade unoriented silicon steel according to claim 1, characterized in that the soaking temperature is 1000-1150 ℃; During the heating of the steel billet, when the temperature of the steel billet is 350-800 ℃, controlling the heating rate to be 5-15 ℃ per minute; when the temperature of the steel billet is 800-1150 ℃, the heating rate is controlled to be more than or equal to 15 ℃ per minute.
  14. 14. The method for producing high-grade unoriented silicon steel according to claim 1 or 13, characterized in that the thickness of the steel billet is 200-250 mm, the equiaxed grain ratio is not less than 65%, and the concave depth of the narrow section is not more than 3mm.
  15. 15. The method for producing the high-grade unoriented silicon steel according to claim 13, characterized in that the hot rolling process comprises the steps of preparing a middle blank from a billet through multi-pass rough rolling and preparing a hot rolled plate through multi-pass finish rolling, wherein the initial rolling temperature of the first-pass finish rolling is more than or equal to 950 ℃, and the final rolling temperature of the last-pass finish rolling is (830-880) +/-15 ℃; And a coiling step, namely coiling the steel at a temperature of 600-650+/-15 ℃.
  16. 16. The production method of the high-grade non-oriented silicon steel according to claim 15, wherein the thickness of the non-oriented silicon steel is more than 0.15mm and not more than 0.50mm, and the thicknesses of the corresponding intermediate billet, the hot rolled plate and the hard rolled plate are respectively 38-50 mm, 2.3-3.5 mm and 0.4-1.2 mm; a heating step, namely soaking at a soaking temperature of 1080-1150 ℃; a hot rolling step, namely, the total rolling reduction of finish rolling is 90-96%, and the rolling reduction of final pass finish rolling is 20-25%; in the single-frame fine cold rolling process, the total rolling reduction is 40-65%; In the annealing process, the annealing temperature is T t1 +/-10 ℃, the annealing time is 100-120 s, the unit of T t1 is the temperature, the value of the T t1 is in a formula 900+200 (11 Si-14Mn+21Al), and element symbols in the formula represent the mass percentage of corresponding elements in the steel billet.
  17. 17. The method for producing high-grade non-oriented silicon steel according to claim 15, wherein the thickness of the non-oriented silicon steel is 0.05-0.15 mm, and the thicknesses of the corresponding intermediate billet, hot rolled plate and hard rolled plate are respectively 30-40 mm, 1.8-2.3 mm and 0.2-0.35 mm; In the heating process, soaking temperature is 1000-1140 ℃; in the hot rolling process, the final rolling temperature of final pass finish rolling is 850+/-15 ℃, the total rolling reduction rate of finish rolling is 93-95%, and the rolling reduction rate of final pass finish rolling is 20-25%; in the coiling process, the coiling temperature is 630+/-15 ℃; In the hard-rolling plate normalizing process, the normalizing temperature is 850-950 ℃; in the single-frame fine cold rolling process, the total rolling reduction is 50-80%; In the annealing process, the annealing temperature is T t2 +/-10 ℃, the annealing time length (30-50) s+400h s/mm, h is the thickness of the refined cold-rolled sheet and the unit is mm, T t2 is the unit and takes the value of the formula 820+200 (11 Si-14Mn+21Al) +400h mm -1 , and the element symbols in the formula represent the mass percentage of corresponding elements in the steel billet.
  18. 18. The production method of the high-grade non-oriented silicon steel according to claim 1, wherein the non-oriented silicon steel comprises, by mass, less than or equal to 0.005% of C, 1.5-4.5% of Si, 0.2-1.5% of Mn, 0.30-1.5% of Al, 1.7-4.8% of Si+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%, and no Sn and Sb or 0.01-0.15% of any one or two of 0.01-0.15% of Sb, and the other being Fe and unavoidable impurities; Or the chemical components of the non-oriented silicon steel 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 0.0030% 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, less than or equal to 0.1% of Mo, nb, V, ti% of each, and 0.01-0.15% of Sn or 0.01-0.15% of Sb, and the balance of Fe and unavoidable impurities; Or the chemical components of the non-oriented silicon steel comprise, by mass, less than or equal to 0.005% of C, 3.2-3.7% of Si, 0.3-0.8% of Mn, 0.70-1.2% 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%, and 0.01-0.15% of Sn or 0.01-0.15% of Sb or any one or two of Fe and unavoidable impurities.

Description

Production method of high-grade unoriented silicon steel with cold rolling smooth operation and dimensional precision Technical Field The application belongs to the technical field of steel material preparation, relates to a production method of a series of high-grade non-oriented silicon steel, and in particular relates to a production method of high-grade non-oriented silicon steel with cold rolling smooth operation and dimensional accuracy. Background The non-oriented silicon steel is a core soft magnetic material for manufacturing iron cores of motors and transformers, and the performance of the non-oriented silicon steel directly influences the energy efficiency and the operation stability of equipment. With the improvement of energy efficiency standards, the demand for high-grade (high silicon and high aluminum) non-oriented silicon steel is increasing. The materials have higher requirements on dimensional accuracy while pursuing high magnetic induction and low iron loss. The same plate difference, namely the uniformity of the transverse thickness and the stability of the longitudinal thickness of the steel plate, is a key dimension precision index and directly influences the stacking coefficient, the loss and the dynamic balance performance of the iron core. The high-grade non-oriented silicon steel has poor plasticity, high hardness and poor rollability of the hot rolled plate due to the high silicon-aluminum content. In order to improve the final magnetic property, a normalizing process is added after hot rolling in the conventional process, but the cold rolling processing property of the sheet is further reduced in the process. In order to ensure continuous strip and reduce edge cracking in the rolling process, the prior production technology mainly adopts a compromise scheme of strictly controlling the upper limit of components and the normalizing temperature so as to maintain limited plasticity, adopts a large initial pass reduction rate and adopts a 'side wave' mode for rolling to relieve the stress of the edge. However, the above strategy to ensure cold rolling compliance has significant contradiction and drawbacks in dimensional accuracy control: firstly, an effective means for improving the uniformity of the transverse thickness (particularly the edge drop control) is to use a special roll shape for 'tight edge' rolling, but the method directly conflicts with a 'edge wave' rolling mode adopted for edge crack prevention in principle, so that the traditional process is to ensure that the production is smooth preferentially, the edge drop active control is abandoned, and the transverse identical plate difference is difficult to reduce further. Secondly, the iron scale on the surface of the hot rolled plate influences the temperature measurement precision in the subsequent normalizing heating, so that the normalized plate is uneven in structure (such as recrystallization degree and grain size) along the length direction, and the structure difference is presented as deformation resistance fluctuation in cold rolling, so that the automatic thickness control system (AGC) is difficult to regulate and control, and the longitudinal thickness precision of a finished product is difficult to ensure. In summary, the existing high-grade non-oriented silicon steel production process (hot rolling, normalizing and cold rolling) has inherent contradiction that the normalizing process for improving the magnetic performance improves the magnetic induction, but the control of the dimensional accuracy is limited due to the deterioration of the rollability and the introduction of the longitudinal uneven structure. How to break through the bottleneck in the process flow design, realize the control of high accuracy with the plate difference while guaranteeing magnetic property and rolling forward, have become the technical problem that the urgent needs of the field to solve. Disclosure of Invention In order to solve the technical problems, the application aims to provide a production method of high-grade unoriented silicon steel with cold rolling smooth operation and dimensional accuracy. In order to achieve the purpose of the application, an embodiment of the application provides a production method of high-grade unoriented silicon steel. The non-oriented silicon steel is a steel plate with the thickness of 0.05-0.50 mm, the longitudinal thickness fluctuation is less than or equal to +/-3 mu m and/or the transverse thickness difference is less than or equal to 5 mu m, the production method comprises a heating process, a hot rolling process, a coiling process, an acid continuous rolling process, a hard plate rolling normalizing process, a single-frame finish cold rolling process and an annealing process in sequence, wherein: An acid continuous rolling procedure, namely the reduction rate of the first-pass cold rolling is 20-30%, and the reduction rate is less than or equal to 0.70mm; Normalizing the obtained hard rol