CN-121976111-A - Non-aluminum high-grade non-oriented silicon steel based on hard plate normalizing and production method thereof

CN121976111ACN 121976111 ACN121976111 ACN 121976111ACN-121976111-A

Abstract

The application discloses non-aluminum high-grade non-oriented silicon steel based on hard plate rolling normalization and a production method thereof. The production method comprises the steps of (1) carrying out hot rolling on a continuous casting blank to obtain a hot rolled plate with the thickness of 1.8-3.5 mm, (3) carrying out acid continuous rolling on the hot rolled plate to obtain a hard rolled plate with the thickness of 0.2-1.2 mm, (4) carrying out normalizing treatment on the hard rolled plate at the normalizing temperature of 850-1000+/-10 ℃ for 60-100 seconds, (5) carrying out 2-4 times of finish rolling on the normalized hard rolled plate by adopting a single-stand cold rolling mill, and the total reduction rate is 40-80%, so as to obtain a finish rolled plate, and (6) carrying out annealing on the finish rolled plate to obtain a non-oriented silicon steel finished product with the thickness of 0.05-0.50+/-0.003 mm.

Inventors

YUE ZHONGXIANG
Zhu henan
WU SHENGJIE
CHEN GANG
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: 20260505
Application Date: 20260226

Claims (12)

1. A production method of aluminum-free high-grade non-oriented silicon steel is characterized by comprising the following steps of, (1) Steelmaking and continuous casting Preparing 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 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 respectively, less than or equal to 0.1% of Mo, nb, V, ti% of Fe and unavoidable impurities; (2) Heating and hot rolling Heating the continuous casting billet, and carrying out two-stage hot rolling to obtain a hot rolled plate with the thickness of 1.8-3.5 mm; (3) Acid continuous rolling Pickling and continuously cold-rolling the hot-rolled plate to obtain a hard-rolled plate with the thickness of 0.2-1.2 mm; (4) Normalizing rolled hard plate Normalizing the hard rolled plate in a normalizing furnace at the normalizing temperature of 850-1000+/-10 ℃ for 60-100 s; (5) Single frame finish cold rolling Adopting a single-frame cold rolling mill to perform 2-4 times of finish cold rolling on the normalized rolled hard plate, wherein the total rolling reduction is 40-80%, and obtaining a finish rolling plate; (6) Annealing And (3) annealing the finish rolling plate to obtain a non-oriented silicon steel finished product with the thickness of (0.05-0.50) +/-0.003 mm.
2. The method for producing aluminum-free high-grade non-oriented silicon steel according to claim 1, wherein the chemical components of the continuous casting billet are not added with Sn and Sb or contain one or two of 0.01-0.15% of Sn and 0.01-0.15% of Sb in percentage by mass.
3. The method for producing aluminum-free high-grade non-oriented silicon steel according to claim 1, wherein the thickness of the continuous casting blank is 200-250 mm, the equiaxed crystal rate is more than or equal to 65%, and the concave depth of the narrow section is less than or equal to 3mm.
4. The method for producing aluminum-free high-grade non-oriented silicon steel according to claim 3, wherein in the step (1), the pulling rate in continuous casting is controlled to be 0.80-1.10 m/min.
5. The method for producing aluminum-free high grade no-orientation silicon steel according to claim 4, wherein in the step (1), when the molten steel at the steelmaking end point satisfies 1.5 to 2.0% of Si, the pulling rate at the continuous casting is controlled to be 1.00 to 1.10m/min, when the molten steel at the steelmaking end point satisfies 2.0% < Si <3.0%, the pulling rate at the continuous casting is controlled to be 0.90 to 1.00m/min, and when the molten steel at the steelmaking end point satisfies 3.0 to 4.5% of Si, the pulling rate at the continuous casting is controlled to be 0.80 to 0.90m/min.
6. The method for producing aluminum-free high-grade non-oriented silicon steel according to claim 1, wherein in the step (2), the charging temperature is more than or equal to 350 ℃ and the soaking temperature is 1000-1150 ℃, the heating rate is controlled to be 5-15 ℃ per minute when the temperature of a continuous casting billet is 350-800 ℃, and the heating rate is controlled to be more than or equal to 15 ℃ per minute when the temperature of the continuous casting billet is 800-1150 ℃.
7. The method for producing aluminum-free high grade no-orientation silicon steel according to claim 1, wherein in the step (2), the hot rolling period comprises a plurality of rough rolling passes and a plurality of finish rolling passes, the initial rolling temperature of the first finish rolling pass is not less than 950 ℃, the final rolling temperature of the last finish rolling pass is (830-880) ± 15 ℃, the total rolling reduction rate of the finish rolling is 90-96%, and the rolling reduction rate of the last finish rolling pass is 20-25%; in the step (2), after hot rolling, the hot rolled plate is coiled at a coiling temperature of 600-650+/-15 ℃.
8. The method for producing aluminum-free high-grade non-oriented silicon steel according to claim 1, wherein in the step (3), normalization is not performed before pickling, preheating is not performed before continuous cold rolling, the reduction rate of the first-pass cold rolling is 20-30%, and the reduction is less than or equal to 0.70mm.
9. The method for producing aluminum-free high grade no-orientation silicon steel according to claim 1, wherein in the step (4), the normalizing is performed in a normalizing furnace in which a weakly reducing atmosphere is maintained; The weak reducing atmosphere can be a mixed atmosphere of H 2 and N 2 , and the volume ratio of H 2 in the mixed atmosphere is 15-25%; The tension in the normalizing furnace is 8-10N/mm 2 ; And (3) performing temperature control cooling after normalizing, wherein the cooling speed is 10-15 ℃ per second when the surface temperature of the steel plate is more than or equal to 400 ℃, and the cooling speed is 15-20 ℃ per second when the surface temperature of the steel plate is less than 400 ℃.
10. The method for producing aluminum-free high grade no-orientation silicon steel according to claim 1, wherein in the step (5), the reduction rate of the first pass finish cold rolling is more than or equal to 30%, the reduction rate is less than or equal to 0.40mm, and the rolling force of each pass finish cold rolling is less than or equal to 6000kN; The working rolls of the single-frame cold rolling mill are in a flat roll form, and the middle rolls have single-side taper of 0.20-0.30%; During finish cold rolling, the middle roller of the single-frame cold rolling mill is driven to axially move.
11. The method for producing aluminum-free high-grade non-oriented silicon steel according to claim 1, wherein in the step (6), the tension in an annealing furnace is controlled to be 1-3N/mm 2 , the annealing temperature is 850-1050 ℃, the annealing time is 40-120 s, and after the annealing time is reached, the sectional control cooling is adopted; The sectional control cooling comprises the cooling speed of 5-10 ℃ per second when the surface temperature of the steel plate is more than 700 ℃, the cooling speed of 10-15 ℃ per second when the surface temperature of the steel plate is 400-700 ℃, and the cooling speed of 15-20 ℃ per second when the surface temperature of the steel plate is less than 400 ℃.
12. The non-oriented silicon steel is characterized by comprising, 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, less than or equal to 0.1% of Ni and Cu respectively, and the balance of Fe and unavoidable impurities; The thickness of the non-oriented silicon steel is 0.50+/-0.003 mm, the iron loss P 1.5/50 is less than or equal to 3.6W/kg, and the magnetic induction intensity B 5000 is more than or equal to 1.65T; Or the thickness of the non-oriented silicon steel is 0.35+/-0.003 mm, the iron loss P 1.5/50 is less than or equal to 3.0W/kg and/or the iron loss P 1.0/400 is less than or equal to 18.5W/kg, and the magnetic induction intensity B 5000 is more than or equal to 1.65T; Or the thickness of the non-oriented silicon steel is (0.20-0.30) +/-0.003 mm, the iron loss P 1.0/400 is less than or equal to 14.5W/kg, and the magnetic induction intensity B 5000 is more than or equal to 1.63T; Or the thickness of the non-oriented silicon steel is (0.05-0.15) +/-0.003 mm, the iron loss P 1.0/400 is less than or equal to 9.5W/kg, the iron loss P 0.5/1000 is less than or equal to 15.0W/kg, and the magnetic induction intensity B 5000 is more than or equal to 1.63T.

Description

Non-aluminum high-grade non-oriented silicon steel based on hard plate normalizing and production method thereof Technical Field The application belongs to the technical field of steel material preparation, and relates to non-aluminum high-grade non-oriented silicon steel based on rolling hard plate normalization and a production method thereof. Background The magnetic properties (especially iron loss and magnetic induction) of the non-oriented silicon steel, which is used as a core soft magnetic material for manufacturing the iron cores of electrical equipment such as motors, transformers and the like, directly determine the energy efficiency level of the equipment. Along with the continuous improvement of energy efficiency standards in the global scope, the requirements for high-performance and high-grade non-oriented silicon steel are increasingly urgent. In order to improve the magnetic properties of non-oriented silicon steel, particularly to reduce iron loss, alloying routes for increasing the content of silicon (Si) and aluminum (Al) are generally adopted to increase the resistivity of the material and reduce eddy current loss. Therefore, conventional high grade non-oriented silicon steel is typically a "high Si high Al" composition system. However, this route faces serious challenges in practical production, in that the increase of Si and Al contents significantly worsens the plasticity of the steel after hot rolling, resulting in extremely easy occurrence of edge cracking and strip breakage problems in the subsequent cold rolling process, which becomes a core bottleneck restricting stable production of high-grade products. In order to solve the problems, the prior main technical scheme generally adopts a combination strategy of strictly controlling the upper limit of Si and Si+Al content, which limits the potential of further improving the magnetic performance through alloying, and carrying out normalizing treatment on the hot rolled plate before cold rolling, so as to recrystallize the deformed ferrite structure formed by hot rolling, refine and homogenize the structure, thereby laying a foundation for obtaining good magnetic performance later, but the normalizing treatment can further reduce the plasticity of the steel plate. In order to realize rolling under the condition of plastic deterioration, the prior art has to increase the procedures of pickling the normalized plate, preheating before cold rolling and the like, and continuously pursue the reduction of the thickness of the hot rolled plate and the improvement of the reduction rate of the first pass of cold rolling. The complexity and the energy consumption of the production process are increased, the harsh requirements on hot rolling and cold rolling equipment are also increased, and part of high-grade products can only be produced by adopting a single-frame multi-pass reciprocating cold rolling or twenty-high rolling mill with low efficiency, so that the production efficiency and the cost control are seriously restricted. In particular, the technical challenges are more prominent for "non-aluminum" high grade non-oriented silicon steel with no added aluminum or extremely low aluminum content. Due to the lack of aluminum contribution to resistivity and regulation of precipitates (such as AlN) by aluminum element, higher silicon content is often required to meet the magnetic performance requirement of the same high grade, which further aggravates the deterioration of material plasticity. Meanwhile, the aluminum-free steel lacks the pinning effect of AlN precipitates in the normalizing process, the grain growth behavior of the aluminum-free steel is different from that of aluminum-containing steel, and conventional normalizing parameters can not be applicable any more, so that balance between normalizing cancellation and magnetic performance guarantee is difficult to achieve. Therefore, under the prior art framework, the production of the aluminum-free high-grade non-oriented silicon steel faces multiple dilemmas of long flow, narrow process window, high production difficulty, low efficiency, difficult full performance and the like. Disclosure of Invention In order to solve the technical problems, the application aims to provide non-aluminum high-grade non-oriented silicon steel based on the normalization of a hard rolling plate and a production method thereof. In order to achieve the purpose of the application, one embodiment of the application provides a production method of aluminum-free high-grade non-oriented silicon steel. The production method comprises the following steps of, (1) Steelmaking and continuous casting Preparing 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 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