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CN-121992296-A - High-grade non-oriented silicon steel and preparation method thereof

CN121992296ACN 121992296 ACN121992296 ACN 121992296ACN-121992296-A

Abstract

The invention discloses high-grade non-oriented silicon steel and a preparation method thereof, and relates to the technical field of non-oriented silicon steel. The high-grade non-oriented silicon steel comprises, by weight, less than or equal to 0.002% of C, 3.0-3.6% of Si, 0.15-0.25% of Mn, 0.05-0.20% of Als, less than or equal to 0.001% of S, less than or equal to 0.015% of P, less than or equal to 0.0015% of N, less than or equal to 0.002% of Ti, and the balance of Fe and unavoidable impurities. A manufacturing method of high-grade non-oriented silicon steel according to claim 1 sequentially comprises the following steps of converter smelting, RH refining, continuous casting, heating, hot rolling, coiling, normalizing, pickling, cold rolling, annealing and coating, wherein the heating temperature is controlled to be 1110-1200 ℃, the hot rolling comprises rough rolling and finish rolling, the hot rolling temperature is controlled to be 900-1000 ℃, the coiling temperature is 550-600 ℃, the normalizing temperature is 850-970 ℃, the total cold rolling reduction is 80-87 ℃, and the annealing temperature is 840-960 ℃. The invention realizes the cooperative promotion of low iron loss and high magnetic induction by precisely controlling the chemical components and the two-section annealing process.

Inventors

  • Ding Shineng
  • LU TIANLIN
  • SHI LIFA
  • XIA XUELAN
  • QI XUAN
  • ZHAN YUNGAO
  • CHEN MINGXIA
  • XU WENXIANG
  • LIU QINGSONG
  • CHENG GUOQING

Assignees

  • 马鞍山钢铁有限公司

Dates

Publication Date
20260508
Application Date
20260123

Claims (10)

  1. 1. The high-grade non-oriented silicon steel is characterized by comprising the following components in percentage by weight: less than or equal to 0.002 percent of C, 3.0 to 3.6 percent of Si, 0.15 to 0.25 percent of Mn, 0.05 to 0.20 percent of Als, less than or equal to 0.001 percent of S, less than or equal to 0.015 percent of P, less than or equal to 0.0015 percent of N, less than or equal to 0.002 percent of Ti, and the balance of Fe and unavoidable impurities.
  2. 2.A method for manufacturing high grade non-oriented silicon steel as claimed in claim 1, comprising the steps of, in order: Converter smelting, RH refining, continuous casting, heating, hot rolling, coiling, normalizing, pickling, cold rolling, annealing and coating; wherein the heating temperature is controlled to be 1110-1200 ℃; The hot rolling comprises rough rolling and finish rolling, and the hot rolling temperature is controlled to be 900-1000 ℃; The coiling temperature is 550-600 ℃; the normalizing temperature is 850-970 ℃; The total rolling reduction rate of cold rolling is 80-87%; the annealing temperature is 840-960 ℃.
  3. 3. The method for manufacturing high grade non-oriented silicon steel as set forth in claim 2, wherein: the surface temperature of the casting blank obtained by continuous casting is more than or equal to 500 ℃ before heating.
  4. 4. The method for manufacturing high grade non-oriented silicon steel as set forth in claim 2, wherein: The heating adopts a multi-stage heating mode, the heating temperature of the first stage is controlled to be 950-1050 ℃, the heating temperature of the second stage is controlled to be 1050-1150 ℃, the heating temperature of the third stage is controlled to be 1150-1200 ℃, and the total heating time is not less than 180min.
  5. 5. The method for manufacturing high grade non-oriented silicon steel as set forth in claim 2, wherein: The rough rolling finishing temperature is 960-1000 ℃, and the finish rolling finishing temperature is 900-930 ℃.
  6. 6. The method for manufacturing high grade non-oriented silicon steel as set forth in claim 2, wherein: the heat preservation after coiling is more than or equal to 24 hours, and the heat preservation temperature is more than or equal to 500 ℃.
  7. 7. The method for manufacturing high grade non-oriented silicon steel as set forth in claim 2, wherein: the normalizing temperature is 890-930 ℃, and the normalizing time is controlled to be 1-3 min.
  8. 8. The method for manufacturing high grade non-oriented silicon steel as set forth in claim 2, wherein: the pickling temperature is 75-90 ℃.
  9. 9. The method for manufacturing high grade non-oriented silicon steel as set forth in claim 2, wherein: the reduction rate of the last pass of the cold rolling is less than or equal to 20 percent.
  10. 10. The method for manufacturing high grade non-oriented silicon steel as set forth in claim 2, wherein: The partial pressure P (H 2 O)/the partial pressure P (H 2 ) of hydrogen in annealing is less than 0.005, the mixed gas of H 2 and N 2 is adopted in the furnace for protection in annealing, the ratio of H 2 to N 2 is 4:6, the annealing adopts a multi-stage annealing mode, the temperature of one-stage annealing is 850+/-10 ℃, the time of one-stage annealing is 120s, the dew point of one-stage annealing is-15 ℃, the temperature of two-stage annealing is 950+/-10 ℃, the time of two-stage annealing is 60s, and the dew point of two-stage annealing is-30 ℃.

Description

High-grade non-oriented silicon steel and preparation method thereof Technical Field The invention relates to the technical field of non-oriented silicon steel, in particular to high-grade non-oriented silicon steel and a preparation method thereof. Background The high-grade non-oriented silicon steel is a core soft magnetic material for manufacturing high-efficiency motors, new energy automobile driving motors and precise instruments, and becomes a product with high technical barriers and high added value in the steel industry due to the characteristics of high magnetic induction, low iron loss and high strength. The high-grade non-oriented silicon steel needs to meet a plurality of harsh electromagnetic and mechanical property indexes at the same time, and the indexes are often mutually restricted, so that the technical challenges are great, and the indexes comprise high magnetic induction, low iron loss, high strength and good stamping processability. The technical difficulties for realizing the performance are that 1. The challenge of performance balance is that dislocation and precipitation are always introduced to improve strength, which hinders magnetic domain movement and increases iron loss, the increase of silicon content can reduce iron loss but increases brittleness, which is unfavorable for processing and punching, 2. The pure steel and accurate composition control is that the content of impurity elements such as C, N, S, O is extremely low (usually less than or equal to 0.0025%), and elements forming harmful precipitates such as Ti, nb and V are required to be precisely controlled, 3. The structure and texture control is that coarse and favorable textures are obtained through normalizing treatment, cold rolling and annealing processes to improve magnetic induction, or the dislocation strengthening is utilized to realize the ultra-high strength. The core of the high-grade non-oriented silicon steel is how to cooperatively optimize the magnetic property and the mechanical property of the high-grade non-oriented silicon steel through precise component design, extreme process control and innovative strengthening mechanism so as to meet the requirements of modern high-energy conversion equipment. The manufacturing difficulty of high-grade silicon steel is that the requirements on iron loss, magnetic induction and mechanical properties are mutually contradictory, and the cooperative regulation and control on component design and process development are required. In the prior art, some patents and researches have attempted to improve the product quality by optimizing means such as component control, heat treatment process, cold rolling process and the like, but still have a larger improvement space. The Chinese patent publication No. CN120519760A discloses a high-efficiency low-energy consumption non-oriented silicon steel magnetic property optimization and production method, which comprises the following steps of 1) component design in percentage by mass, 2) process steps of smelting and continuous casting, hot rolling, selective normalizing, cooling control, cold rolling and annealing, wherein the total reduction rate is 70% to 85%, the annealing adopts two-stage type, the front-stage 850+/-10 ℃ wet atmosphere, and the rear-stage 950+/-10 ℃ dry atmosphere. Through the synergistic optimization of component design and process, the magnetic performance of the high-grade non-oriented silicon steel product is improved while the energy consumption of the normalizing process is reduced. The implementation effect of the case is B50=1.72T, P1.5/50=3.2W/kg, and the iron loss is high. Disclosure of Invention The invention aims at overcoming the defects of the prior art, and provides high-grade non-oriented silicon steel, which comprises the following components in percentage by weight: less than or equal to 0.002 percent of C, 3.0 to 3.6 percent of Si, 0.15 to 0.25 percent of Mn, 0.05 to 0.20 percent of Als, less than or equal to 0.001 percent of S, less than or equal to 0.015 percent of P, less than or equal to 0.0015 percent of N, less than or equal to 0.002 percent of Ti, and the balance of Fe and unavoidable impurities. The manufacturing method of the high-grade non-oriented silicon steel sequentially comprises the following steps: Converter smelting, RH refining, continuous casting, heating, hot rolling, coiling, normalizing, pickling, cold rolling, annealing and coating, wherein the heating temperature is controlled to be 1110-1200 ℃, the hot rolling comprises rough rolling and finish rolling, the hot rolling temperature is controlled to be 900-1000 ℃, the coiling temperature is 550-600 ℃, the normalizing temperature is 850-970 ℃, the total rolling reduction is 80-87%, and the annealing temperature is 840-960 ℃. Further, the surface temperature of the casting blank obtained by continuous casting is more than or equal to 500 ℃ before heating. Further, the heating adopts a multi-stage heating mode, the he