Production method of ultra-low anisotropic non-oriented silicon steel for oversize generator

Abstract

The invention discloses a production method of ultra-low anisotropic non-oriented silicon steel for an oversize generator. The production method comprises the steps of molten iron pretreatment, converter steelmaking, RH refining, continuous casting of molten steel into a plate blank, hot rolling, normalizing pickling, cold rolling, annealing, coating and finishing. Wherein the non-oriented electrical steel comprises the following components in percentage by weight: less than or equal to 0.003% of C, 2.80-3.60% of Si, 0.15-0.45% of Mn, less than or equal to 0.04% of P, 0.4-1.2% of Als, less than or equal to 0.002% of S and the balance of Fe and other inevitable impurities; a continuous annealing furnace is adopted for annealing, the annealing temperature of a heating section and a soaking section is controlled to be 860-1030 DEG C, the speed of the strip steel is 90-130 m / min, the unit tension of the strip steel at an inlet and an outlet of the annealing furnace is smaller than 2.5 N / mm < 2 >, and the unit tension of the strip steel at the soaking section in the annealing furnace is smaller than 1 N / mm < 2 >. According to the non-oriented silicon steel, the iron loss P15 / 50 is smaller than or equal to 2.5 W / kg, the magnetic induction B50 is larger than or equal to 1.65 T, the magnetic induction B100 is larger than or equal to 1.76 T, the iron loss P15 / 50 anisotropy is smaller than or equal to 8%, and P10 / 50C is smaller than or equal to 1.12 W / kg.

Description

technical field [0001] The invention relates to the production technology of non-oriented silicon steel, in particular to a production method of non-oriented silicon steel with ultra-low anisotropy for extra-large generators. Background technique [0002] Top-grade high-grade non-oriented silicon steel is an important core soft magnetic material for manufacturing variable frequency motors, drive motors, and especially large generators. In the process of magnetization, affected by factors such as matrix atomic arrangement and orbital coupling, the magnetic flux density of silicon steel sheets shows strength differences in different directions. Large-scale laminated stator-rotor motors are used to prevent uneven core magnetic field density from causing unbalanced motor rotation. , while the silicon steel sheet is required to have low iron loss, it is also required that the difference between the longitudinal and transverse iron loss properties is small, that is, the anisotropy...

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Problems solved by technology

[0005] Chinese Patent No. CN201610562185.4 discloses "A Production Method for Improving the Electromagnetic Anisotropy of Electrical Steel Products", which mainly achieves the purpose of improving the magnetic anisotropy by controlling the strip elongation and heating rate during annealing; but the main It is effective for medium and high grade non-oriented silicon steel, but not obvious for non-oriented silicon steel with silicon content greater than 2.90%.

[0006] Chinese Patent No. CN201810081918.1 discloses "a preparation method of thin strip continuous casting low magnetic anisotropy non-oriented silicon steel", which mainly adopts thin strip continuous casting technology, controls hot rolling reduction rate and other processes, and simultaneously adds Sn, etc. Elements, to achieve the purpose of producing low magnetic anisotropy non-oriented silicon steel; this invention is suitable for non-oriented silicon steel with silicon content less than 2.0%, adopts thin strip continuous casting technology, advanced technology but not suitable for large-scale production process of conventional equipment

At present, the anisotropy of high-grade non-oriented silicon steel widely used in the market is 12-13%, and the performance of P10 / 50C (that is, the iron loss in the transverse direction of the silicon steel sheet under the magnetic field strength of 1 Tesla and 50 Hz) is 1.15W / kg. The above cannot meet the performance requirements of high-grade non-oriented electrical steel for large-scale hydropower and nuclear power such as the Three Gorges

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