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JP-7855698-B2 - Non-oriented electrical steel sheet with good magnetic properties and method for manufacturing the same

JP7855698B2JP 7855698 B2JP7855698 B2JP 7855698B2JP-7855698-B2

Inventors

  • リ、グオバオ
  • チャン、フェン
  • ファン、シャンシ
  • ワン、ボ
  • リュウ、シュエジュン

Assignees

  • バオシャン アイアン アンド スティール カンパニー リミテッド

Dates

Publication Date
20260508
Application Date
20230105
Priority Date
20220107

Claims (7)

  1. The following chemical elements in mass percentage: 0 < C ≤ 0.0010 %, Si: 0.2-1.8%, Mn: 0.2-0.4%, Al: 0.2-0.6%, V: 0.002-0.005 %, and N < 0.002% ; and the remainder being Fe and unavoidable impurities. It consists of , It contains N-containing inclusions having a size of 200-500 nm, A non-oriented electrical steel sheet having a volume fraction ratio of VN to N-containing inclusions of ≥0.85 .
  2. The non-oriented electrical steel sheet according to claim 1 , wherein the unavoidable impurities satisfy Nb < 0.002% and Ti < 0.002%.
  3. The non-oriented electrical steel sheet according to claim 1 or 2, wherein the N-containing inclusions are primarily composed of N-containing inclusions, and the N-containing inclusions comprise individual VN, AlN, and/or composite VN, AlN, NbN, and TiN.
  4. The non-oriented electrical steel sheet according to claim 1 or 2, having an iron loss P 15/50 of ≤4.2 W/kg and a magnetic induction B 50 of ≥1.73 T.
  5. A method for manufacturing a non-oriented electrical steel sheet according to claim 1 or 2, comprising the following steps: (1) The process of smelting and casting; (2) Hot rolling process, in which the steel coil obtained after hot rolling is introduced directly to the next process without being subjected to normalizing annealing or coating annealing; (3) The process of pickling to obtain pickled steel sheets; (4) A process of cold rolling a pickled steel sheet to obtain a cold-rolled steel sheet; and (5) A manufacturing method comprising a continuous annealing step, in which the cold-rolled steel sheet is heated to a target immersion temperature at a heating rate of 50-5000°C/s.
  6. The manufacturing method according to claim 5 , wherein step (5) satisfies at least one of the following conditions: The target immersion temperature is 500-1100°C; The cold-rolled steel sheet is heated to the target immersion temperature at a heating rate of 80-550°C/s.
  7. The manufacturing method according to claim 5 , wherein step (2) satisfies at least one of the following conditions: During hot rolling, the time the cast slab remains in the furnace is controlled to 120-360 minutes, the initial rolling temperature is controlled to 1000-1250°C, the final rolling temperature is controlled to 650-1000°C, and the coil winding temperature is controlled to 550-950°C. The hot-rolled steel sheet is controlled to have a target thickness of 0.8–3.5 mm; and/or in step (4), the pickled steel sheet is cold-rolled in one step to the target cold-rolled thickness.

Description

Technical Field: The present invention relates to steel sheets and methods for manufacturing the same, and more particularly to non-oriented electrical steel sheets and methods for manufacturing the same. Background: In prior art, non-oriented electrical steel sheets are commonly used to manufacture stators and rotors for iron cores used in motors, generators, compressors, and high-speed motors, drive motors, and other products. However, in recent years, as the demand for high efficiency, energy saving, and consumption reduction has increased in the user market, existing non-oriented electrical steel sheets are gradually failing to meet market demands. Therefore, it is urgent to develop non-oriented electrical steel sheets with higher magnetic induction and lower iron loss to satisfy the new technological requirements of the market for non-oriented electrical steel sheets. To achieve the best possible electromagnetic performance for non-oriented electrical steel sheets, some researchers have conducted extensive studies and achieved certain research results, but the results for practical applications have not been very satisfactory. For example, Chinese patent application publication CN103014503A, published on April 3, 2013, titled "Acid-resistant, non-oriented silicon steel with high magnetic induction and low iron loss without normalizing, and method for manufacturing the same," points out that by adding 0.20%-0.45% Sn+Cu to steel, the microstructure of the final strip steel can be improved due to grain boundary segregation, resulting in good magnetic induction performance. However, since Sn and Cu are precious metals, this significantly increases the manufacturing cost of the steel, and Cu tends to cause associated quality defects on the surface of the strip steel. Therefore, in practical application processes, the technical solution of this patent application has strict requirements for the manufacturing process, and the resulting product has relatively low cost-effectiveness. As another example, Japanese Patent Application Publication No. 10-183227 and Japanese Patent Application Publication No. 2004-169141 point out that by adding appropriate amounts of rare earth elements and calcium alloys to the steel, inclusions in the steel can be removed by strong deoxidation and desulfurization of the molten steel, and the cleanliness of the steel can be improved, resulting in an efficient and favorable improvement of the electromagnetic performance of the final strip steel. Furthermore, the above Japanese patent documents also point out that by reducing harmful elements C, S, O, N, Nb, V, and Ti in the steel, and simultaneously combining high tapping temperature, high final rolling temperature, and high coil winding temperature in the hot rolling process, a hot-rolled steel sheet with coarse particles can be obtained, which is beneficial for roughening inclusions and therefore plays a good role in promoting the improvement of the magnetic performance of the final strip steel. However, the disadvantages of such technical solutions are that the significant increase in preheating temperature and the shift in the phase transition point result in high energy consumption during hot rolling, poor stability in the finish rolling process, and the high coil winding temperature easily induce red scale defects. In light of the above, the inventors designed and intended to obtain a novel non-oriented electrical steel sheet with excellent magnetic properties, with the aim of improving the electromagnetic performance of electrical steel, reducing iron loss, and improving magnetic induction. Figure 1 schematically shows the relationship between the volume fraction ratio of vanadium nitride (VN) to N-containing inclusions in the steel in the non-oriented electrical steel sheet according to the present invention and the iron loss P 15/50 of the finished steel sheet.Figure 2 schematically shows the relationship between the heating rate of rapid heating in the non-oriented electrical steel sheet according to the present invention and the magnetic induction B 50 of the finished steel sheet.Figure 3 is a photograph of the microstructure of the completed non-oriented electrical steel sheet of Example 3.Figure 4 is a photograph of the microstructure of the comparative steel in Comparative Example 2. Detailed Description: The non-oriented electrical steel sheet having good magnetic performance according to the present invention and the method for manufacturing the same are further described and illustrated with reference to the accompanying drawings and specific examples. However, the description and illustrated should not be construed as constituting an undue limitation to the technical solutions of the present invention. Examples 1-6 and Comparative Examples 1-3 Table 1 shows the mass percentages of chemical elements in the non-oriented electrical steel sheets of Examples 1-6 and the comparative steel sheets of Comparative Examples 1