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KR-20260064959-A - NON-ORIENTED ELECRICAL STEEL SHEET AND METHOD OF MANUFACTURING THE SAME

KR20260064959AKR 20260064959 AKR20260064959 AKR 20260064959AKR-20260064959-A

Abstract

The present invention provides a non-oriented electrical steel sheet comprising, in weight percent, silicon (Si): 3% or more and 3.8% or less, manganese (Mn): 0.2% or more and 0.4% or less, aluminum (Al): 0.8% or more and 1.5% or less, carbon (C): greater than 0% and 0.002% or less, phosphorus (P): greater than 0% and 0.015% or less, sulfur (S): greater than 0% and 0.002% or less, nitrogen (N): greater than 0% and 0.002% or less, titanium (Ti): greater than 0% and 0.002% or less, and the remainder being iron (Fe) and other unavoidable impurities, satisfying the following formula 1. <Equation 1> In the above Equation 1, V def is the area fraction (area %) of grains with a GOS value of 1° or more on the TD plane of the non-oriented electrical steel sheet, and V rx is the area fraction (area %) of grains with a GOS value of less than 1° on the TD plane of the non-oriented electrical steel sheet.

Inventors

  • 채원기
  • 조한혁
  • 김민성
  • 최혜정
  • 고재현

Assignees

  • 현대제철 주식회사

Dates

Publication Date
20260508
Application Date
20241030

Claims (4)

  1. In non-oriented electrical steel sheets, In weight percent, silicon (Si): 3% or more and 3.8% or less, manganese (Mn): 0.2% or more and 0.4% or less, aluminum (Al): 0.8% or more and 1.5% or less, carbon (C): greater than 0% and 0.002% or less, phosphorus (P): greater than 0% and 0.015% or less, sulfur (S): greater than 0% and 0.002% or less, nitrogen (N): greater than 0% and 0.002% or less, titanium (Ti): greater than 0% and 0.002% or less, and the remainder being iron (Fe) and other unavoidable impurities, Non-oriented electrical steel sheet satisfying the following Equation 1. <Equation 1> In the above Equation 1, V def is the area fraction (area %) of grains with a GOS value of 1° or more on the TD plane of the non-oriented electrical steel sheet, and V rx is the area fraction (area %) of grains with a GOS value of less than 1° on the TD plane of the non-oriented electrical steel sheet.
  2. In paragraph 1, The above non-oriented electrical steel sheet is a non-oriented electrical steel sheet having a yield strength of 700 MPa or more and an iron loss of 27 W/kg or less (based on W 10/400 ).
  3. In a method for manufacturing non-oriented electrical steel sheets, A step of preparing a slab comprising, in weight percent: silicon (Si): 3% or more and 3.8% or less, manganese (Mn): 0.2% or more and 0.4% or less, aluminum (Al): 0.8% or more and 1.5% or less, carbon (C): greater than 0% and 0.002% or less, phosphorus (P): greater than 0% and 0.015% or less, sulfur (S): greater than 0% and 0.002% or less, nitrogen (N): greater than 0% and 0.002% or less, titanium (Ti): greater than 0% and 0.002% or less, and the remainder being iron (Fe) and other unavoidable impurities; A step of hot-rolling the above slab to form a hot-rolled plate; A step of forming a hot-rolled annealed plate by hot-rolling and annealing the above hot-rolled plate; A step of forming a cold-rolled plate by cold-rolling the above hot-rolled annealed plate; and The method comprises the step of forming a cold-rolled annealed plate by annealing the above cold-rolled plate at a temperature of 620°C or higher and 680°C or lower for a time of more than 0 seconds and less than or equal to 90 seconds; 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> In the above Equation 1, V def is the area fraction (area %) of grains with a GOS value of 1° or more on the TD plane of the non-oriented electrical steel sheet, and V rx is the area fraction (area %) of grains with a GOS value of less than 1° on the TD plane of the non-oriented electrical steel sheet.
  4. In paragraph 3, A method for manufacturing a non-oriented electrical steel sheet having a yield strength of 700 MPa or more and an iron loss of 27 W/kg or less (based on W 10/400 ).

Description

Non-oriented electrical steel sheet and method of manufacturing the same The embodiments of the present invention relate to a non-oriented electrical steel sheet and a method for manufacturing the same, and more specifically, to a non-oriented electrical steel sheet having high strength and excellent magnetic properties and a method for manufacturing the same. Due to policies aimed at reducing carbon dioxide ( CO2 ) emissions to prevent global warming, existing internal combustion engine vehicles are being rapidly replaced by eco-friendly vehicles (e.g., hybrid electric vehicles (HEV), electric vehicles (EV), etc.), particularly electric vehicles (EV). Electric vehicles (EV) must generate high torque at low speeds or during acceleration, and rotate at high speeds (e.g., 200 Hz or higher) during constant speed and high-speed driving. Therefore, non-oriented electrical steel sheets, which serve as the core material for motors, must possess not only high strength but also excellent magnetic properties, such as low iron loss and high magnetic flux density. Factors affecting the strength and/or magnetic properties of such non-oriented electrical steel sheets include chemical composition, sheet thickness, microstructure, insulating coating layer, and texture. Furthermore, these various factors are influenced by the manufacturing process conditions of the non-oriented electrical steel sheets. Meanwhile, non-oriented electrical steel sheets are manufactured through the processes of steelmaking/continuous casting, hot rolling, heat treatment after hot rolling, cold rolling, heat treatment after cold rolling, and coating. FIG. 1 is a flowchart schematically illustrating a method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention. The present invention is capable of various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various forms. In this specification, terms such as "first," "second," etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another. In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" mean that the features or components described in the specification are present, and do not preclude the possibility that one or more other features or components may be added. In this specification, "A and/or B" indicates the case where it is A, B, or both A and B. And, "at least one of A and B" indicates the case where it is A, B, or both A and B. Where any embodiment in this specification can be implemented differently, a specific process sequence may be performed differently from the order described. For example, two processes described consecutively may be performed substantially simultaneously or proceed in the reverse order of the order described. Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. When describing with reference to the drawings, identical or corresponding components are given the same reference numerals, and redundant descriptions thereof will be omitted. For convenience of explanation, the size of components in the drawings may be exaggerated or reduced. For example, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, so the present invention is not necessarily limited to what is depicted. FIG. 1 is a flowchart schematically illustrating a method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention. Referring to FIG. 1, a method for manufacturing a non-oriented electrical steel sheet according to one embodiment may include a hot rolling step (S100), a cold rolling step (S300), and a cold rolling annealing step (S400). In a method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention, the semi-finished product subject to hot rolling may be a slab. The slab in the semi-finished product state can be obtained through a continuous casting process after obtaining molten steel of a predetermined composition through a steelmaking process. In one embodiment, the slab may comprise silicon (Si), manganese (Mn), aluminum (Al), carbon (C), phosphorus (P), sulfur (S), nitrogen (N), titanium (Ti), the remainder being iron (Fe) and unavoidable impurities. The slab may comprise, in weight percent, silicon (Si): 3.0% or more and 3.8% or less, mangane