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KR-20260064983-A - Non-oriented electrical steel sheet, motor containing the same, and method for manufacturing non-oriented electrical steel sheet

KR20260064983AKR 20260064983 AKR20260064983 AKR 20260064983AKR-20260064983-A

Abstract

The present invention provides a non-oriented electrical steel sheet, wherein, in weight% (wt%), silicon (Si): 0.1 to 1.6%, aluminum (Al): 0.5% or less (greater than 0), manganese (Mn): 0.2 to 0.4%, carbon (C): 0.0050% or less (greater than 0), sulfur (S): 0.0050% or less (greater than 0), nitrogen (N): 0.0030% or less (greater than 0), titanium (Ti): 0.0050% or less (greater than 0), phosphorus (P): 0.1% or less (greater than 0), and the remainder being iron (Fe) and other unavoidable impurities, wherein the volume fraction of TiC precipitates with an average diameter of 200 nm or less within the non-oriented electrical steel sheet is 20% or less, and the volume fraction of MnS precipitates with an average diameter of 200 nm or less is 20% or less.

Inventors

  • 김민성
  • 채원기
  • 고재현
  • 최혜정

Assignees

  • 현대제철 주식회사

Dates

Publication Date
20260508
Application Date
20241030

Claims (17)

  1. As a non-oriented electrical steel sheet, In weight% (wt%), silicon (Si): 0.1 to 1.6%, aluminum (Al): 0.5% or less (greater than 0), manganese (Mn): 0.2 to 0.4%, carbon (C): 0.0050% or less (greater than 0), sulfur (S): 0.0050% or less (greater than 0), nitrogen (N): 0.0030% or less (greater than 0), titanium (Ti): 0.0050% or less (greater than 0), phosphorus (P): 0.1% or less (greater than 0), and the remainder being iron (Fe) and other unavoidable impurities, A non-oriented electrical steel sheet in which the volume fraction of TiC precipitates with an average diameter of 200 nm or less is 20% or less, and the volume fraction of MnS precipitates with an average diameter of 200 nm or less is 20% or less.
  2. In paragraph 1, A non-oriented electrical steel sheet having an iron loss (W 15/50 ) of 7.0 W/kg or less.
  3. In paragraph 1, The above non-oriented electrical steel sheet has a magnetic flux density (B 50 ) of 1.75T or more.
  4. In paragraph 1, Non-oriented electrical steel sheet having a final microstructure grain size of 50㎛ to 160㎛.
  5. In paragraph 1, A non-oriented electrical steel sheet having a tensile strength (TS) of 500 MPa or more and a yield strength (YP) of 400 MPa or more.
  6. As a method for manufacturing non-oriented electrical steel sheets, A continuous casting step for forming a slab comprising, in weight% (wt%), silicon (Si): 0.1 to 1.6%, aluminum (Al): 0.5% or less (greater than 0), manganese (Mn): 0.2 to 0.4%, carbon (C): 0.0050% or less (greater than 0), sulfur (S): 0.0050% or less (greater than 0), nitrogen (N): 0.0030% or less (greater than 0), titanium (Ti): 0.0050% or less (greater than 0), phosphorus (P): 0.1% or less (greater than 0), and the remainder being iron (Fe) and other unavoidable impurities; A hot rolling step of manufacturing a hot-rolled plate by reheating the above slab, then hot-rolling and coiling it; A cold rolling step for manufacturing a cold rolled plate by cold rolling the above hot rolled plate; and A cold rolling annealing step for manufacturing a cold rolling annealed plate by annealing the above cold rolling plate; Includes, In the above hot rolling step, the coiling temperature is performed at less than 600℃, and A method for manufacturing a non-oriented electrical steel sheet, wherein the volume fraction of MnS precipitates with an average diameter of 200 nm or less in the final microstructure is 20% or less,
  7. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the slab temperature is maintained at 800℃ or higher between the continuous casting step and the reheating step.
  8. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet, wherein, in the above hot rolling step, the reheating temperature range is 800°C or higher.
  9. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet, wherein, in the above hot rolling step, the finishing rolling temperature range is 800℃ or higher.
  10. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet in which the volume fraction of TiC precipitates with an average diameter of 200 nm or less in the final microstructure is 20% or less.
  11. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet having a final microstructure grain size of 50㎛ to 160㎛.
  12. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the iron loss (W 15/50 ) of the above non-oriented electrical steel sheet is 7.0 W/kg or less.
  13. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the magnetic flux density (B 50 ) of the above non-oriented electrical steel sheet is 1.75T or higher.
  14. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the tensile strength (TS) of the non-oriented electrical steel sheet is 500 MPa or more and the yield strength (YP) is 400 MPa or more.
  15. A motor comprising a motor core, wherein the motor core is, It comprises a non-oriented electrical steel sheet comprising, in weight% (wt%), silicon (Si): 0.1 to 1.6%, aluminum (Al): 0.5% or less (greater than 0), manganese (Mn): 0.2 to 0.4%, carbon (C): 0.0050% or less (greater than 0), sulfur (S): 0.0050% or less (greater than 0), nitrogen (N): 0.0030% or less (greater than 0), titanium (Ti): 0.0050% or less (greater than 0), phosphorus (P): 0.1% or less (greater than 0), and the remainder being iron (Fe) and unavoidable impurities. A motor in which the volume fraction of TiC precipitates with an average diameter of 200 nm or less in the above-mentioned non-oriented electrical steel sheet is 20% or less, and the volume fraction of MnS precipitates with an average diameter of 200 nm or less is 20% or less.
  16. In paragraph 15, A motor in which the iron loss (W 15/50 ) of the above non-oriented electrical steel sheet is 7.0 W/kg or less.
  17. In paragraph 15, A motor in which the magnetic flux density (B 50 ) of the above non-oriented electrical steel sheet is 1.75T or greater.

Description

Non-oriented electrical steel sheet, motor containing the same, and method for manufacturing non-oriented electrical steel sheet The present invention relates to a non-oriented electrical steel sheet and a method for manufacturing the same. A motor generates mechanical energy by using electrical energy as the driving force to rotate an internal iron core. The internal iron core is formed by stacking multiple sheets of non-oriented electrical steel that have been punched into the shapes of a stator and a rotor; in this process, the magnetic properties of the non-oriented electrical steel have a dominant influence on the performance of the motor (or motor core). The magnetic properties of non-oriented electrical steel are evaluated by magnetic flux density and iron loss. Magnetic flux density is related to the motor's torque, while iron loss is the amount of energy lost as heat. To increase the energy efficiency of motors, the iron loss of non-oriented electrical steel sheets must be reduced. This can be achieved by adding major alloying elements such as silicon (Si), manganese (Mn), and aluminum (Al) to increase resistivity, thinning the material, or controlling the grain size and precipitate size through heat treatment. However, major alloying elements readily combine with impurity elements such as carbon (C), sulfur (S), nitrogen (N), and titanium (Ti) to form precipitates. These formed precipitates hinder the movement of magnetic domains formed by an applied magnetic field, thereby degrading magnetic properties and reducing rollability, which can make it difficult to thin the steel sheet. Therefore, research on managing precipitates in non-oriented electrical steel sheets is actively underway. 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. FIG. 2 is a temperature graph schematically illustrating a part of a method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present invention. Figure 3 is a temperature graph schematically illustrating a part of the method for manufacturing a non-oriented electrical steel sheet according to a comparative example of the present invention. The present invention will be described in detail below. However, in describing the present invention, if it is determined that a detailed description of related known technologies or configurations may unnecessarily obscure the essence of the present invention, such detailed description will be omitted. In the following embodiments, terms such as first, second, etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another component. In the following examples, singular expressions include plural expressions unless the context clearly indicates otherwise. In the following embodiments, when various components such as layers, films, regions, and plates are described as being "on" another component, this includes not only cases where they are "directly on" another component, but also cases where another component is interposed between them. In the drawings, the size of components may be exaggerated or reduced for convenience of explanation. For example, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and therefore the present invention is not necessarily limited to what is illustrated. In the following embodiments, terms such as "include" or "have" 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. Additionally, in this specification, "at least one of A and B" indicates the case where it is A, B, or both A and B. Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined. Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. 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. FIG. 2 is a temperature graph schematically illustrating a part of the method for manufacturing a non-oriented electrical steel sheet according to one embodiment of the present in