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KR-20260065009-A - NON-ORIENTED ELECTRICAL STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME

KR20260065009AKR 20260065009 AKR20260065009 AKR 20260065009AKR-20260065009-A

Abstract

A non-oriented electrical steel sheet according to one embodiment of the present invention can provide a non-oriented electrical steel sheet with excellent magnetic properties by including silicon (Si) 2.8 wt% or more and 3.7 wt% or less, aluminum (Al) 0.8 wt% or more and 1.5 wt% or less, manganese (Mn) 0.2 wt% or more and 0.4 wt% or less, chromium (Cr) 0.02 wt% or more and 0.07 wt% or less, copper (Cu) 0.02 wt% or more and 0.07 wt% or less, nickel (Ni) 0.02 wt% or more and 0.07 wt% or less, niobium (Nb) greater than 0 wt% and 0.002 wt% or less, and the remainder being iron (Fe) and other unavoidable impurities.

Inventors

  • 고재현
  • 강춘구
  • 이강노
  • 박대범

Assignees

  • 현대제철 주식회사

Dates

Publication Date
20260508
Application Date
20241031

Claims (16)

  1. A non-oriented electrical steel sheet comprising silicon (Si) 2.8 wt% or more and 3.7 wt% or less, aluminum (Al) 0.8 wt% or more and 1.5 wt% or less, manganese (Mn) 0.2 wt% or more and 0.4 wt% or less, chromium (Cr) 0.02 wt% or more and 0.07 wt% or less, copper (Cu) 0.02 wt% or more and 0.07 wt% or less, nickel (Ni) 0.02 wt% or more and 0.07 wt% or less, niobium (Nb) greater than 0 wt% and 0.002 wt% or less, and the remainder being iron (Fe) and other unavoidable impurities.
  2. In paragraph 1, A non-oriented electrical steel sheet further comprising carbon (C) greater than 0 wt% and less than or equal to 0.003 wt%, titanium (Ti) greater than 0 wt% and less than or equal to 0.003 wt%, sulfur (S) greater than 0 wt% and less than or equal to 0.005 wt%, nitrogen (N) greater than 0 wt% and less than or equal to 0.005 wt%, and phosphorus (P) greater than 0 wt% and less than or equal to 0.015 wt%.
  3. In paragraph 1, Non-oriented electrical steel sheet satisfying the following Equation 1: [Equation 1] [i(70, 0, 0) / i(23, 45, 45)] ≥ 0.8 In Equation 1, i(70, 0, 0) is the strength of the orientation distribution function of a grain with (φ 1 , φ, φ 2 ) = (70±3, 0, 0) Euler angle (Bunge) orientation, and i(23, 45, 45) is the strength of the orientation distribution function of a grain with (φ 1 , φ, φ 2 ) = (23±3, 45±5, 45±2) Euler angle (Bunge) orientation.
  4. In paragraph 3, Non-oriented electrical steel sheet in which i(70, 0, 0) is 4.8 or greater and 6.5 or less.
  5. In paragraph 3, Non-oriented electrical steel sheet in which i(23, 45, 45) is 5.3 or greater and 6.6 or less.
  6. In paragraph 1, A non-oriented electrical steel sheet having 85 or fewer CrN precipitates with a diameter of 10 nm or more per area (50 µm × 50 µm).
  7. In paragraph 1, A non-oriented electrical steel sheet having 1 to 6 NbN precipitates with a diameter of 10 nm or more per area (50㎛×50㎛).
  8. In paragraph 1, Non-oriented electrical steel sheet having an average diameter of NbN precipitates per area (50㎛×50㎛) of 130 nm or more and 227 nm or less.
  9. In paragraph 1, Non-oriented electrical steel sheet with iron loss (W 10/400 ) of 14.6 W/kg or less.
  10. Step of hot rolling the slab after reheating; Hot rolling and annealing step; cold rolling step; and It includes a cold rolling and annealing step, The above slab is, A method for manufacturing a non-oriented electrical steel sheet comprising silicon (Si) 2.8 wt% or more and 3.7 wt% or less, aluminum (Al) 0.8 wt% or more and 1.5 wt% or less, manganese (Mn) 0.2 wt% or more and 0.4 wt% or less, chromium (Cr) 0.02 wt% or more and 0.07 wt% or less, copper (Cu) 0.02 wt% or more and 0.07 wt% or less, nickel (Ni) 0.02 wt% or more and 0.07 wt% or less, niobium (Nb) greater than 0 wt% and 0.002 wt% or less, and the remainder being iron (Fe) and other unavoidable impurities.
  11. In Paragraph 10, The above cold rolling annealing step is, A method for manufacturing non-oriented electrical steel sheets by performing heat treatment in a temperature range of 800℃ or higher and 1100℃ or lower.
  12. In Paragraph 10, The above slab is, A method for manufacturing a non-oriented electrical steel sheet, further comprising carbon (C) greater than 0 wt% and less than or equal to 0.003 wt%, titanium (Ti) greater than 0 wt% and less than or equal to 0.003 wt%, sulfur (S) greater than 0 wt% and less than or equal to 0.005 wt%, nitrogen (N) greater than 0 wt% and less than or equal to 0.005 wt%, and phosphorus (P) greater than 0 wt% and less than or equal to 0.015 wt%.
  13. In Paragraph 10, The non-oriented electrical steel sheet that has undergone the above-mentioned cold rolling and annealing step is, A method for manufacturing a non-oriented electrical steel sheet satisfying the following Equation 1: [Equation 1] [i(70, 0, 0) / i(23, 45, 45)] ≥ 0.8 In Equation 1, i(70, 0, 0) is the strength of the orientation distribution function of a grain with (φ 1 , φ, φ 2 ) = (70±3, 0, 0) Euler angle (Bunge) orientation, and i(23, 45, 45) is the strength of the orientation distribution function of a grain with (φ 1 , φ, φ 2 ) = (23±3, 45±5, 45±2) Euler angle (Bunge) orientation.
  14. In Paragraph 13, The non-oriented electrical steel sheet that has undergone the above-mentioned cold rolling and annealing step is, A method for manufacturing non-oriented electrical steel sheets in which i(70, 0, 0) is 4.8 or greater and 6.5 or less.
  15. In Paragraph 13, The non-oriented electrical steel sheet that has undergone the above-mentioned cold rolling and annealing step is, A method for manufacturing non-oriented electrical steel sheets in which i(23, 45, 45) is 5.3 or more and 6.6 or less.
  16. In Paragraph 10, The non-oriented electrical steel sheet that has undergone the above-mentioned cold rolling and annealing step is, A method for manufacturing non-oriented electrical steel sheets having an iron loss (W 10/400 ) of 14.6 W/kg or less.

Description

Non-oriented electrical steel sheet and method for manufacturing the same The present invention relates to a non-oriented electrical steel sheet and a method for manufacturing a non-oriented electrical steel sheet. Recently, in accordance with global policies to reduce carbon dioxide emissions and prevent global warming, conventional internal combustion engine vehicles are being rapidly replaced by eco-friendly vehicles such as hybrid, electric, and hydrogen cars. Eco-friendly vehicles utilize electric motors to generate the driving force required for the vehicle and can reduce environmental pollution by significantly decreasing the emission of harmful exhaust gases. As interest in and demand for such eco-friendly vehicles increase, the demand for electric motors, which generate the driving force for the vehicle, is also rising. An electric motor is a device that uses electricity to generate the driving force required for a vehicle, and energy efficiency—the ability to operate for a longer period using the same amount of energy—is a crucial technical factor. To increase the energy efficiency of such electric motors, it is essential to improve the magnetic performance of the non-oriented electrical steel sheets used as the core material. Non-oriented electrical steel is a material that possesses uniform magnetic properties in all directions regardless of the rolling direction; to enhance energy efficiency, iron loss must be reduced and magnetic flux density increased. Iron loss and magnetic flux density are greatly influenced by the alloy composition of non-oriented electrical steel sheets, and in particular, the reduction of impurity elements is essential to achieve low iron loss and high magnetic flux density. Conventionally, non-oriented electrical steel sheets were manufactured using slabs produced in blast furnaces to reduce impurities. However, manufacturing slabs in blast furnaces results in very high carbon and greenhouse gas emissions, which can cause environmental pollution. Consequently, research and development are currently underway to manufacture non-oriented electrical steel sheets using electric furnaces in order to solve the environmental pollution problems associated with the use of blast furnaces. However, when slabs are manufactured using an electric furnace, a large amount of impurity elements may be included. Representative impurity elements include chromium (Cr), copper (Cu), and nickel (Ni), which are called tramp elements, and sulfur (S) and nitrogen (N) are also representative impurity elements. If the aforementioned impurity elements are present in large quantities, the magnetic properties of the final product, non-oriented electrical steel sheets, may be degraded. Therefore, to improve the magnetic properties of non-oriented electrical steel sheets manufactured in electric furnaces, it is necessary to optimize alloying and impurity elements, and to improve the microstructure and texture that affect magnetic flux density and iron loss. Figure 1 is a photograph showing the texture and orientation distribution function of a non-oriented electrical steel sheet according to Example 1-3 of the experimental examples of the present invention. Figure 2 is a photograph showing the texture and orientation distribution function of non-oriented electrical steel sheets according to Comparative Examples 1-7 among the experimental examples of the present invention. Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention is not limited or restricted by the following embodiments. Additionally, when it is stated that a component (or area, layer, part, etc.) is "on," "connected," or "combined" with another component, it means that it may be directly placed/connected/combined with the other component, or that a third component may be placed between them. Terms such as "include" or "have" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification. Furthermore, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning