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KR-20260064993-A - NON-ORIENTED ELECTRICAL STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME

KR20260064993AKR 20260064993 AKR20260064993 AKR 20260064993AKR-20260064993-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 can be obtained, and specifically, a (200) plane texture can be strongly formed, thereby enabling low iron loss.

Inventors

  • 이한샘
  • 안용근
  • 유성현
  • 최수영

Assignees

  • 현대제철 주식회사

Dates

Publication Date
20260508
Application Date
20241030

Claims (15)

  1. In wt%, Si: 1.8 wt% or more and 4.0 wt% or less, Mn: 0.05 wt% or more and 0.5 wt% or less, Al: greater than 0 ppm and 100 ppm or less, P: greater than 0 ppm and 150 ppm or less, Ti: greater than 0 ppm and 50 ppm or less, S: greater than 0 ppm and 200 ppm or less, rare earth elements: greater than 0 ppm and 50 ppm or less, and the remainder being Fe and other unavoidable impurities, (200) Non-oriented electrical steel sheet in which the strength of the surface satisfies the following Equation 1. [Equation 1] P(200)/[P(all)] ≥ 0.35 (In Equation 1 above, P(200) represents the diffraction peak intensity of the (200) plane, and P(all) represents the sum of the diffraction peak intensities of all crystal planes measured at 2θ = 30 to 150°.)
  2. In Article 1, A non-oriented electrical steel sheet comprising two or more of the rare earth elements La, Sm, Ce, Yb, and Dy.
  3. In Article 1 or Article 2, Non-oriented electrical steel sheet with iron loss of 12.5 W/kg or less.
  4. In Article 1 or Article 2, Non-oriented electrical steel sheet with a thickness of 0.10 mm or more and 0.25 mm or less.
  5. A step of manufacturing a hot-rolled steel sheet by reheating and hot-rolling a slab containing Si: 1.8 wt% or more and 4.0 wt% or less, Mn: 0.05 wt% or more and 0.5 wt% or less, Al: greater than 0 ppm and 100 ppm or less, P: greater than 0 ppm and 150 ppm or less, Ti: greater than 0 ppm and 50 ppm or less, S: greater than 0 ppm and 200 ppm or less, rare earth elements: greater than 0 ppm and 50 ppm or less, and the remainder being Fe and other unavoidable impurities; Step of annealing the hot-rolled steel sheet; Step of shot blasting and pickling annealed hot-rolled steel sheets; A step of manufacturing a cold-rolled steel sheet by cold-rolling the above shot-blasted and pickled steel sheet; and The above cold-rolled steel sheet includes the step of final annealing, A method for manufacturing a non-oriented electrical steel sheet, wherein the final annealing step is heat-treated for 4 hours or more and 50 hours or less at a temperature of 950°C or more and 1250°C or less and a hydrogen fraction of 30% or more.
  6. In Article 5, A method for manufacturing a non-oriented electrical steel sheet satisfying the following Equation 1. [Equation 1] P(200)/[P(all)] ≥ 0.35 (In Equation 1 above, P(200) represents the diffraction peak intensity of the (200) plane, and P(all) represents the sum of the diffraction peak intensities of all crystal planes measured at 2θ = 30 to 150°.)
  7. In Article 5 or 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the above rare earth elements include two or more of La, Sm, Ce, Yb, and Dy.
  8. In Article 5 or 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the step of manufacturing the hot-rolled steel sheet comprises heat treatment at a reheating temperature of 1000°C or higher and 1250°C or lower, and a heating time of 350 minutes or more and 850 minutes or less.
  9. In Article 5 or 6, The step of manufacturing the above hot-rolled steel sheet is a method for manufacturing a non-oriented electrical steel sheet in which the hot-rolling finishing temperature is 850°C or higher and 1000°C or lower.
  10. In Article 5 or 6, The step of manufacturing the above hot-rolled steel sheet is a method for manufacturing a non-oriented electrical steel sheet in which the coiling temperature after rolling is 550°C or higher and 750°C or lower.
  11. In Article 5 or 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the step of annealing the hot-rolled sheet above involves heat treatment at a heating rate of 20℃/s or more, a heat treatment temperature of 900℃ or more and 1100℃ or less, and a duration of 10 seconds or more and 180 seconds or less.
  12. In Article 5 or 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the above shot blasting step is performed by rotating fine particles with a size of 2 μm or more and 1200 μm or less at a speed of 2000 rpm or more and under high-speed conditions of 50 m/s or more and 120 m/s or less, and the above pickling step is performed by supplying 18% hydrochloric acid to a pickling tank where a reaction with the steel sheet takes place.
  13. In Article 5 or 6, The step of manufacturing the above cold-rolled steel sheet is a method for manufacturing a non-oriented electrical steel sheet, wherein the hot-rolled sheet from which a surface oxide layer has been removed by shot blasting and pickling is cold-rolled at a reduction rate of 65% or more and 97% or less.
  14. In Article 5 or 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the thickness of the hot-rolled steel sheet is 1.8 mm or more and 3.5 mm or less.
  15. In Article 5 or 6, A method for manufacturing a non-oriented electrical steel sheet, wherein the thickness of the cold-rolled steel sheet is 0.1 mm or more and 0.25 mm or less.

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. With increasing interest in reducing CO2 emissions due to recent global environmental issues, there is a growing trend of conventional internal combustion engine vehicles being rapidly replaced by eco-friendly vehicles, such as hybrid electric vehicles (HEVs) and especially electric vehicles (EVs). In line with this increasing demand for EVs, electric motors, which are one of the core components used in electric vehicles, must guarantee high output sufficient to replace the output of internal combustion engines, and to achieve this, it is necessary to use electrical steel sheets with excellent magnetic properties. Electrical steel sheets are broadly classified into two types: oriented electrical steel, which exhibits excellent magnetic properties in a specific direction, and non-oriented electrical steel, which displays uniform magnetic properties in all directions. The representative physical properties of electrical steel sheets are core loss, which represents energy loss, and magnetic flux density, which represents power output. To achieve excellent properties, it is necessary to adjust factors such as chemical composition, sheet thickness, microstructure, and external shape. In addition, to improve the properties of electrical steel sheets, it is necessary to control the texture in a direction that has excellent magnetic properties. It is known that the magnetic properties in the texture are best in the (100) orientation called Cube, followed by (110), and worst in the (111) orientation. Therefore, oriented electrical steel sheets, which require excellent magnetic properties in a specific direction, can exhibit excellent magnetic properties if they have a (110)<001> texture called GOSS, and non-oriented electrical steel sheets exhibit the best properties in the (100)<001> texture. Figure 1 is a diagram showing XRD crystal plane data of Example 12-5 of the present application. 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 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. This application relates to non-oriented electrical steel sheets, which are core materials used in motors that convert electrical energy into mechanical energy. In the composition of electrical steel sheets, sulfur (S) is a key element that creates a favorable environment for the growth of a texture with excellent magnetic properties by controlling the surface energy of the electrical steel sheets. However, since sulfur reacts with H₂ , the final annealing atmosphere, to form H₂S and escapes in the form of gas during annealing, it is important to appropriately control the annealing temperature and time and to form a compound that can retain sulfur in the base material for a long time. The above non-oriented electrical steel sheet contains, in weight%, Si: 1.8 wt% or more and 4.0 wt% or less, Mn: 0.05 wt% or more and 0.5 wt% or less, Al: greater than 0 ppm and 100 ppm or less, P: greater than 0 ppm and 150 ppm or less, Ti: greater than 0 ppm and 50 ppm or less, S: greater than 0 ppm and 200 ppm or less, rare earth elements: greater than 0 ppm and 50 ppm or less, and the remainder being Fe and other unavoidable impurities, and the strength of the (200) plane satisfies the following formula 1. [Equation 1] P(200)/[P(all)] ≥ 0.35 (In the above Equation 1, P(200) represents the diffraction peak intensity of the (200) plane, and P(all) represents the sum of the diffraction peak intensities of all crystal planes measured at 2θ = 30 to 150°.) Specifically, Equation 1 above formulas the fraction of plane intensity of the (200) plane relative to the total crystal planes of a non-oriented electrical steel sheet, indicating how strongly the (200) plane is formed relative to random orientation. P(200) is the XRD diffraction peak intensity of the (200) plane, and P(all) represents the sum of the XRD diffraction peak intensities of all crystal planes measured between 2θ = 30 and 150°. The P(200) and P(all) diffraction peaks are the average values of measurements taken at 10 locations spaced 15 mm apart during X-ray diffraction analysis (XRD) measurement. If the value of Equation 1 above is 0.35 or higher, the intensity of the (200) peak is very high, so it can be considered that the texture of the (200) plane, which has excellent magnetic properties, has developed significantly.