Search

KR-20260064980-A - NON-ORIENTED ELECTRICAL STEEL SHEET AND METHOD OF MANUFACTURING THE SAME

KR20260064980AKR 20260064980 AKR20260064980 AKR 20260064980AKR-20260064980-A

Abstract

The present invention provides a non-oriented electrical steel sheet comprising, in wt%, silicon (Si): 2.8 wt% to 3.8 wt%, manganese (Mn): 0.2 wt% to 0.5 wt%, aluminum (Al): 0.5 wt% to 1.5 wt%, carbon (C): greater than 0 and less than or equal to 0.003 wt%, sulfur (S): greater than 0 and less than or equal to 0.002 wt%, phosphorus (P): greater than 0 and less than or equal to 0.015 wt%, nitrogen (N): greater than 0 and less than or equal to 0.002 wt%, titanium (Ti): greater than 0 and less than or equal to 0.002 wt%, and the remainder being iron (Fe) and unavoidable impurities, wherein the ratio (YR0/YR90) of the 0-degree direction yield ratio (YR0) and the 90-degree direction yield ratio (YR90) of the non-oriented electrical steel sheet is 1 or less.

Inventors

  • 오규진
  • 강춘구

Assignees

  • 현대제철 주식회사

Dates

Publication Date
20260508
Application Date
20241030

Claims (11)

  1. As a non-oriented electrical steel sheet, In wt%, silicon (Si): 2.8 wt% to 3.8 wt%, manganese (Mn): 0.2 wt% to 0.5 wt%, aluminum (Al): 0.5 wt% to 1.5 wt%, carbon (C): greater than 0 and less than or equal to 0.003 wt%, sulfur (S): greater than 0 and less than or equal to 0.002 wt%, phosphorus (P): greater than 0 and less than or equal to 0.015 wt%, nitrogen (N): greater than 0 and less than or equal to 0.002 wt%, titanium (Ti): greater than 0 and less than or equal to 0.002 wt%, and the remainder being iron (Fe) and unavoidable impurities, A non-oriented electrical steel sheet in which the ratio (YR0/YR90) of the 0-degree direction yield ratio (YR0) and the 90-degree direction yield ratio (YR90) of the above non-oriented electrical steel sheet is 1 or less.
  2. In paragraph 1, A non-oriented electrical steel sheet having an average iron loss (W 10/400 ) in the 0-degree and 90-degree directions of the above non-oriented electrical steel sheet of 12.5 W/kg or less.
  3. In paragraph 1, The above non-oriented electrical steel sheet is a non-oriented electrical steel sheet having a yield strength of 400 MPa or more.
  4. In paragraph 1, The above non-oriented electrical steel sheet is a non-oriented electrical steel sheet having a yield ratio (yield strength/tensile strength) of 0.74 or higher.
  5. In paragraph 1, The above non-oriented electrical steel sheet further comprises 0.01 wt% to 0.05 wt% of at least one of tin (Sn) and antimony (Sb).
  6. As a method for manufacturing non-oriented electrical steel sheets, A step of manufacturing a hot-rolled plate by hot-rolling a slab comprising, in wt%, silicon (Si): 2.8 wt% to 3.8 wt%, manganese (Mn): 0.2 wt% to 0.5 wt%, aluminum (Al): 0.5 wt% to 1.5 wt%, carbon (C): greater than 0 and less than or equal to 0.003 wt%, sulfur (S): greater than 0 and less than or equal to 0.002 wt%, phosphorus (P): greater than 0 and less than or equal to 0.015 wt%, nitrogen (N): greater than 0 and less than or equal to 0.002 wt%, titanium (Ti): greater than 0 and less than or equal to 0.002 wt%, and the remainder being iron (Fe) and unavoidable impurities; A step of manufacturing a hot-rolled annealed plate by hot-rolling the above hot-rolled plate at a hot-rolling annealing temperature of 950℃ to 1050℃; A step of manufacturing a cold-rolled plate by cold-rolling the above hot-rolled annealed plate; and A step of manufacturing a cold-rolled annealed plate by cold-rolling the above cold-rolled plate at a cold-rolling annealing temperature of 975℃ to 1050℃; Includes, A method for manufacturing a non-oriented electrical steel sheet, wherein the above hot rolling annealing temperature and the above cold rolling annealing temperature satisfy Equation 1 below. <Equation 1> 0 ≤ (T 1 - T 2 ) 2 / T 2 ≤ 2.5 In the above Equation 1, T1 is the hot rolling annealing temperature and T2 is the cold rolling annealing temperature.
  7. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the ratio (YR0/YR90) of the 0-degree direction yield ratio (YR0) and the 90-degree direction yield ratio (YR90) of the above non-oriented electrical steel sheet is 1 or less.
  8. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the average iron loss (W 10/400 ) in the 0-degree and 90-degree directions of the above non-oriented electrical steel sheet is 12.5 W/kg or less.
  9. In paragraph 6, The above non-oriented electrical steel sheet is a method for manufacturing a non-oriented electrical steel sheet having a yield strength of 400 MPa or more.
  10. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet having a yield ratio (yield strength/tensile strength) of 0.74 or higher.
  11. In paragraph 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the above slab further comprises 0.01 wt% to 0.05 wt% of at least one of tin (Sn) and antimony (Sb).

Description

Non-oriented electrical steel sheet and method of manufacturing the same The present invention relates to a non-oriented electrical steel sheet and a method for manufacturing the same. Due to policies aimed at reducing 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)), particularly electric vehicles (EV). In line with the increasing demand for electric vehicles (EV), the energy conversion efficiency of drive motors for electric vehicles is being improved, and for this purpose, excellent magnetic properties of the motor core material are required. Non-oriented electrical steel sheets, used as motor core materials, play a role in converting electrical energy into mechanical energy in rotating machinery; for energy conservation, it is crucial to possess magnetic properties, specifically low iron loss and high magnetic flux density. To satisfy these requirements, Si content, product thickness, grain size, texture, and precipitates must be appropriately controlled. The residual stress following core processing varies depending on the anisotropy of the steel sheet's mechanical properties. If the mechanical anisotropy of the steel sheet is high, the degree of magnetic property degradation after core processing differs, leading to increased magnetic anisotropy in the core. 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. Figures 2 and 3 are schematic diagrams illustrating cross-sections of non-oriented electrical steel sheets after stamping. 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 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, 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 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. Where an embodiment 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 description. 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. 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. A non-oriented electrical steel sheet according to one embodiment of the present invention may comprise silicon (Si), manganese (Mn), aluminum (Al), carbon (C), sulfur (S), phosphorus (P), nitrogen (N), titanium (Ti), the remainder being iron (Fe) and unavoidable impurities. Additionally, the non-oriented electrical steel sheet may further comprise at least one of tin (Sn) and antimony (Sb). The non-oriented electrical steel sheet may contain, in wt%, silicon (Si): 2.8 wt% to 3.8 wt%, manganese (Mn): 0.2 wt% to 0.5 wt%, aluminum (Al): 0.5 wt% to 1.5 wt%, carbon (C): greater than 0 and less than or equal to 0.003 wt%, sulfur (S): greater than 0 and less than or equal to 0.002 wt%, phosphorus (P): greater than 0 and less than or equal to 0.015 wt%, nitrogen (N): greater than 0 and less than or equal to 0.002 wt%, titanium (Ti): greater than 0 and less than or equal to 0.002 wt%, and the remainder being iron (Fe) and unavoidable impurities. Additionally, the non-oriented electrical steel sheet may contain, in wt%, at least one of tin (Sn) and antimony (Sb) in an amount of 0.01 wt% to 0.05 wt%. Silicon (Si) can be an element that in