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KR-20260062214-A - Non-oriented electrical steel sheet and method for manufacturing the same

KR20260062214AKR 20260062214 AKR20260062214 AKR 20260062214AKR-20260062214-A

Abstract

The present invention relates to a non-oriented electrical steel sheet with improved coating bonding strength and a method for manufacturing an electrical steel sheet, comprising 0.3 to 1.3 wt% silicon (Si), 0.2 to 0.4 wt% manganese (Mn), 0.01 to 0.5 wt% aluminum (Al), and the remainder being iron (Fe) and other unavoidable elements, wherein the surface silicon (Si) concentration may be 11% or less.

Inventors

  • 이강노
  • 신경식
  • 강춘구

Assignees

  • 현대제철 주식회사

Dates

Publication Date
20260507
Application Date
20241028

Claims (13)

  1. It comprises 0.3 to 1.3 wt% silicon (Si), 0.2 to 0.4 wt% manganese (Mn), 0.01 to 0.5 wt% aluminum (Al), and the remainder being iron (Fe) and other unavoidable elements, surface roughness of 0.2 or higher and 0.5 or lower, Non-oriented electrical steel sheet.
  2. In paragraph 1, surface silicon (Si) concentration of 11% or less, Non-oriented electrical steel sheet.
  3. In paragraph 2, A non-oriented electrical steel sheet in which the surface roughness (Ra) and the surface silicon (Si) concentration satisfy the following [Equation 1]. [Equation 1] 35 ≤ (Surface roughness (Ra) / Surface silicon (Si) concentration (%)) * 1000 ≤ 335 (However, surface roughness and surface silicon (Si) concentration are values expressed in μm and %, respectively.)
  4. 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%, sulfur (S) greater than 0 wt% and less than or equal to 0.003 wt%, nitrogen (N) greater than 0 wt% and less than or equal to 0.003 wt%, and titanium (Ti) greater than 0 wt% and less than or equal to 0.004 wt%.
  5. A first step of preparing a steel material comprising 0.3 to 1.3 wt% silicon (Si), 0.2 to 0.4 wt% manganese (Mn), 0.01 to 0.5 wt% aluminum (Al), and the remainder being iron (Fe) and other unavoidable elements; A second step of hot-rolling the above steel material to form a hot-rolled steel plate; A third step of pickling the above hot-rolled steel plate at a temperature of 70 to 90 degrees; Fourth step of hot-rolling annealing the above-mentioned pickled hot-rolled steel sheet; A fifth step of cold-rolling the hot-rolled steel sheet that has undergone the fourth step above to form a cold-rolled steel sheet; and A sixth step of cold-rolling and annealing the above cold-rolled steel sheet, Method for manufacturing non-oriented electrical steel sheets.
  6. In paragraph 5, In the above 6th step, the heat treatment temperature is 850 to 1000 degrees, Method for manufacturing non-oriented electrical steel sheets.
  7. In paragraph 5, In the above 6th step, the dew point temperature is -60 to -20 degrees, Method for manufacturing non-oriented electrical steel sheets.
  8. In paragraph 5, After the above 6th step, the surface roughness is 0.2 or higher and 0.5 or lower, Method for manufacturing non-oriented electrical steel sheets.
  9. In paragraph 5, After the above 6th step, the surface silicon (Si) concentration is 11% or less, Method for manufacturing non-oriented electrical steel sheets.
  10. In paragraph 5, A method for manufacturing a non-oriented electrical steel sheet in which, after the above 6th step, the surface roughness (Ra) and the surface silicon (Si) concentration satisfy the following [Equation 1]. [Equation 1] 35 ≤ (Surface roughness (Ra) / Surface silicon (Si) concentration (%)) * 1000 ≤ 335
  11. In paragraph 5, A method for manufacturing a non-oriented electrical steel sheet, wherein the above steel material further comprises carbon (C) 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 0.003 wt%, nitrogen (N) greater than 0 wt% and less than or equal to 0.003 wt%, and titanium (Ti) greater than 0 wt% and less than or equal to 0.004 wt%.
  12. A core for an electric motor comprising an electrical steel sheet according to any one of paragraphs 1 to 4.
  13. An electric motor comprising an electrical steel sheet according to any one of paragraphs 1 through 4.

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. With environmental regulations tightening globally in recent years, 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 that generate the driving force required for the vehicles is also rising. Non-oriented electrical steel sheets are primarily used as core materials for these electric motors, and various factors such as alloying elements, processing conditions, microstructure, and precipitates used in the electrical steel sheets affect the characteristics of the electric motor. One of the key performance characteristics of electrical steel sheets for motors is iron loss. Iron loss refers to the total sum of hysteresis loss, eddy current loss, and anomalous loss, occurring during the magnetization process of the electrical steel sheet, and is measured in W/kg. To improve the iron loss of these electrical steel sheets, methods are used to increase resistivity by adding key alloying elements such as Si, Al, and Mn, or to reduce eddy currents by thinning the material. In addition, electrical steel sheets used in motors are laminated to form an iron core, and an insulating coating is used as a method to reduce iron loss by suppressing the generation of eddy currents in the electrical steel sheets. The insulating coating layer formed on the surface of electrical steel sheets is primarily intended for insulation between sheets, but as it is an important factor affecting processability, weldability, corrosion resistance, and surface quality, related research is actively underway. Although the insulation coating of such electrical steel sheets is typically applied during the final manufacturing process, additional processes such as stamping and high-temperature heat treatment for stress relief are performed for motor manufacturing after the coating layer is formed. This can cause damage to the insulation coating layer, which may lead to a deterioration in product quality. Therefore, to prevent the insulation coating layer from peeling off the surface of the electrical steel sheet during the manufacturing process, the bonding strength between the insulation coating layer and the electrical steel sheet must be enhanced; this bonding strength is closely related to the wettability characteristics of the electrical steel sheet surface. In other words, the better the wettability characteristics of the electrical steel sheet surface, the more strongly the insulation coating layer can bond to the surface. Therefore, there is a need to develop technology that can increase the bonding strength between the insulating coating layer and the electrical steel sheet by improving the wetting characteristics of the electrical steel sheet surface. Figure 1 is a conceptual diagram showing the formation of a surface oxide layer due to surface Si enrichment. FIG. 2 is a flowchart showing a method for manufacturing an electrical steel sheet according to 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 thei