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KR-20260064971-A - NON-ORIENTED ELECTRICAL STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME

KR20260064971AKR 20260064971 AKR20260064971 AKR 20260064971AKR-20260064971-A

Abstract

The present application relates to a non-oriented electrical steel sheet and a method for manufacturing the same. According to the non-oriented electrical steel sheet and the method for manufacturing the same of the present application, excellent magnetic properties may be achieved, specifically, a high fraction of texture favorable for magnetization, low iron loss, and high magnetic flux density may be achieved.

Inventors

  • 채원기
  • 김민성
  • 조한혁

Assignees

  • 현대제철 주식회사

Dates

Publication Date
20260508
Application Date
20241030

Claims (12)

  1. In weight percent, composed of C: greater than 0% and less than or equal to 0.002%, Si: greater than 3.0% and less than or equal to 3.8%, Mn: greater than 0.2% and less than or equal to 0.4%, Al: greater than 0.8% and less than or equal to 1.5%, P: greater than 0% and less than or equal to 0.015%, S: greater than 0% and less than or equal to 0.002%, N: greater than 0% and less than or equal to 0.002%, Ti: greater than 0% and less than or equal to 0.002%, and the remainder being Fe and other unavoidable impurities, and An obstructive electrical steel sheet satisfying the following Equation 1. [Equation 1] 0.85 < V λ-Fiber /V γ-Fiber (In Equation 1, V λ-Fiber : Fraction of {001}<110> bearing + Fraction of {001}<210> bearing + Fraction of {001}<100> bearing, V γ-Fiber : Fraction of {111}<110> orientation + Fraction of {111}<112> orientation)
  2. In Article 1, The above non-oriented electrical steel sheet is a non-oriented electrical steel sheet having a thickness of 0.35 mm or less.
  3. In Article 1 or Article 2, Non-oriented electrical steel sheet having an average grain size of 50㎛ or more and 150㎛ or less.
  4. In Article 1 or Article 2, Non-oriented electrical steel sheet with an iron loss W 10/400 of 12.5 W/kg or less.
  5. A step of manufacturing a hot-rolled steel sheet by reheating and hot-rolling a slab comprising, in weight%, C: greater than 0% and less than or equal to 0.002%, Si: greater than 3.0% and less than or equal to 3.8%, Mn: greater than 0.2% and less than or equal to 0.4%, Al: greater than 0.8% and less than or equal to 1.5%, P: greater than 0% and less than or equal to 0.015%, S: greater than 0% and less than or equal to 0.002%, N: greater than 0% and less than or equal to 0.002%, Ti: greater than 0% and less than or equal to 0.002%, and the remainder being Fe and other unavoidable impurities; A step of manufacturing a cold-rolled steel sheet by cold-rolling the above hot-rolled steel sheet; and A method for manufacturing a non-oriented electrical steel sheet comprising the step of heat-treating and annealing the above-mentioned cold-rolled steel sheet at an annealing temperature, The above non-oriented electrical steel sheet is a method for manufacturing a non-oriented electrical steel sheet satisfying the following Equation 1. [Equation 1] 0.85 < V λ-Fiber /V γ-Fiber (In Equation 1, V λ-Fiber : Fraction of {001}<110> bearing + Fraction of {001}<210> bearing + Fraction of {001}<100> bearing, V γ-Fiber : Fraction of {111}<110> orientation + Fraction of {111}<112> orientation)
  6. In Article 5, A method for manufacturing a non-oriented electrical steel sheet, wherein the annealing step is such that the average heating rate to the annealing temperature is 40℃/s or higher.
  7. In Article 5, A method for manufacturing a non-oriented electrical steel sheet, wherein the annealing step is heat treatment at an annealing temperature of 700°C or higher and 1100°C or lower for 30 seconds or more and 90 seconds or less.
  8. In Article 5, A method for manufacturing a non-oriented electrical steel sheet, wherein the annealing step comprises a cooling step at an average rate of 30℃/s or higher after heat treatment.
  9. In Article 5, A method for manufacturing a non-oriented electrical steel sheet, wherein the annealing step described above has an average heating rate of 50℃/s or more and 100℃/s or less in the temperature range from 650℃ to 750℃ during heating.
  10. In Article 5, A method for manufacturing a non-oriented electrical steel sheet, further comprising, prior to the step of manufacturing the cold-rolled steel sheet, a step of coiling the hot-rolled steel sheet at a temperature of 550°C or higher and 650°C or lower.
  11. In Article 5, A method for manufacturing a non-oriented electrical steel sheet, wherein the thickness of the hot-rolled steel sheet is 1.9 mm or more and 2.4 mm or less.
  12. In Article 5, A method for manufacturing a non-oriented electrical steel sheet having a thickness of 0.35 mm or less, manufactured through the above-mentioned annealing step.

Description

Non-oriented electrical steel sheet and method for manufacturing the same The present application relates to a non-oriented electrical steel sheet and a method for manufacturing the same. Recently, due to policies aimed at reducing CO2 emissions to prevent global warming, conventional internal combustion engine vehicles are being rapidly replaced by eco-friendly vehicles such as hybrid electric vehicles (HEVs) and, in particular, electric vehicles (EVs). These electric vehicles (EVs) must generate high torque at low speeds or during acceleration, and rotate at high speeds of over 200 Hz during constant speed and high-speed driving. Consequently, non-oriented electrical steel sheets, which serve as the core material for motors, must simultaneously satisfy high magnetic flux density and low iron loss. Factors affecting the magnetic properties of such non-oriented electrical steel include chemical composition, thickness, microstructure, insulating coating layer, and/or texture. These various factors are influenced by the manufacturing process conditions of the non-oriented electrical steel. Generally, non-oriented electrical steel is manufactured through the processes of steelmaking/continuous casting, hot rolling, pre-annealing, cold rolling, final annealing, and coating, and excellent magnetic properties can be achieved by optimizing the conditions of each process. Patent Document 1 controls the chemical composition of a non-oriented electrical steel sheet by adding Ni and Cu to obtain excellent magnetic properties and improve strength and elongation, and also controls the microstructure, thickness, and texture of the non-oriented electrical steel sheet. However, there is a concern that adding elements such as Ni and Cu to a non-oriented electrical steel sheet to improve elongation may worsen economic feasibility. Therefore, a non-oriented electrical steel sheet and a method for manufacturing the same are required to solve these problems. Embodiments of the present invention will be described in detail below. Furthermore, the scope of the present invention is not limited to the embodiments described below, and may be implemented with arbitrary modifications within the scope that does not deviate from the gist of the present invention. In the description of numerical ranges in this specification, the notation “X~Y” indicates X or greater and Y or less, unless otherwise specifically stated. Additionally, “greater than or equal to” may be replaced with “greater than,” and “less than or equal to” may be replaced with “less than.” In the numerical ranges described stepwise in this specification, an upper or lower limit value described in any numerical range may be substituted with an upper or lower limit value of another numerical range described stepwise, or may also be substituted with a value shown in the examples. The present application relates to a non-oriented electrical steel sheet, which is a core material used in a motor that converts electrical energy into mechanical energy. The non-oriented electrical steel sheet can satisfy the following Equation 1. [Equation 1] 0.85 < V λ-Fiber /V γ-Fiber In the above Equation 1, V λ-Fiber means the fraction of {001}<110> orientation + the fraction of {001}<210> orientation + the fraction of {001}<100> orientation, and V γ-Fiber means the fraction of {111}<110> orientation + the fraction of {111}<112> orientation. Specifically, the value calculated by Equation 1 of the above non-oriented electrical steel sheet may be greater than 0.85, greater than 0.90, greater than 1.00, greater than 1.10, greater than 1.20, greater than 1.30, or greater than 1.32. By satisfying Equation 1, the fraction of texture favorable to magnetization is high, and excellent magnetic properties can be obtained, specifically, low iron loss and high magnetic flux density can be obtained. If the value calculated by Equation 1 is lower than or equal to the lower limit of the aforementioned numerical range, the fraction of texture unfavorable to magnetization is high, and magnetic properties may deteriorate. The above non-oriented electrical steel sheet may be composed of, in weight percent, C: greater than 0% and less than or equal to 0.002%, Si: greater than or equal to 3.8%, Mn: greater than or equal to 0.2% and less than or equal to 0.4%, Al: greater than or equal to 0.8% and less than or equal to 1.5%, P: greater than 0% and less than or equal to 0.015%, S: greater than 0% and less than or equal to 0.002%, N: greater than 0% and less than or equal to 0.002%, Ti: greater than 0% and less than or equal to 0.002%, and the remainder being Fe and other unavoidable impurities. The composition of the above steel plate is explained below. C: Exceeding 0 wt% and up to 0.002 wt% Carbon (C) is an element that can increase iron loss by combining with other unavoidable impurities to form carbides such as TiC and/or NbC. If the carbon is included in the non-oriented electrical steel sheet in an amount exce