KR-20260062189-A - NON-ORIENTED ELECTRICAL STEEL SHEET AND METHOD OF MANUFACTURING THE SAME

KR20260062189AKR 20260062189 AKR20260062189 AKR 20260062189AKR-20260062189-A

Abstract

The present invention relates to a method for manufacturing a non-oriented electrical steel sheet, comprising: a hot rolling step of manufacturing a hot-rolled sheet by hot rolling a slab comprising, in wt%, silicon (Si): 1.8 wt% to 2.8 wt%, manganese (Mn): 0.1 wt% to 0.5 wt%, aluminum (Al): 0.1 wt% to 0.5 wt%, carbon (C): greater than 0 and less than or equal to 0.005 wt%, phosphorus (P): greater than 0 and less than or equal to 0.1 wt%, sulfur (S): greater than 0 and less than or equal to 0.005 wt%, nitrogen (N): greater than 0 and less than or equal to 0.005 wt%, titanium (Ti): greater than 0 and less than or equal to 0.005 wt%, and the remainder being iron (Fe) and unavoidable impurities; and a hot rolling annealing step of manufacturing a hot-rolled annealed sheet by hot rolling annealing the hot-rolled sheet. A method for manufacturing a non-oriented electrical steel sheet is provided, comprising: a shot blasting step of performing shot blasting on the hot-rolled annealed sheet; a pickling step of pickling the hot-rolled annealed sheet on which shot blasting has been performed for a pickling time of 30 seconds to 90 seconds; a cold rolling step of cold-rolling the hot-rolled annealed sheet to produce a cold-rolled sheet; and a cold-rolling annealing step of annealing the cold-rolled sheet to produce a cold-rolled annealed sheet.

Inventors

곽민석
김성태
이동희
박준영

Assignees

현대제철 주식회사

Dates

Publication Date: 20260507
Application Date: 20241025

Claims (13)

As a method for manufacturing non-oriented electrical steel sheets, A hot rolling step for manufacturing a hot-rolled plate by hot rolling a slab comprising, in wt%, silicon (Si): 1.8 wt% to 2.8 wt%, manganese (Mn): 0.1 wt% to 0.5 wt%, aluminum (Al): 0.1 wt% to 0.5 wt%, carbon (C): greater than 0 and less than or equal to 0.005 wt%, phosphorus (P): greater than 0 and less than or equal to 0.1 wt%, sulfur (S): greater than 0 and less than or equal to 0.005 wt%, nitrogen (N): greater than 0 and less than or equal to 0.005 wt%, titanium (Ti): greater than 0 and less than or equal to 0.005 wt%, and the remainder being iron (Fe) and unavoidable impurities; A hot rolling annealing step for manufacturing a hot rolling annealed plate by hot rolling and annealing the above hot rolling plate; A shot blast step of performing shot blasting on the hot-rolled annealed plate; A pickling step of pickling the hot-rolled annealed plate on which the above shot blast has been performed for a pickling time of 30 to 90 seconds; A cold rolling step for manufacturing a cold rolled plate by cold rolling the above hot-rolled annealed plate; and A cold rolling annealing step for manufacturing a cold rolling annealed plate by annealing the above cold rolling plate; A method for manufacturing a non-oriented electrical steel sheet comprising
In paragraph 1, In the above shot blast step, A method for manufacturing non-oriented electrical steel sheets with a cumulative loss of 30 g/mm² or less .
In paragraph 1, A method for manufacturing a non-oriented electrical steel sheet, wherein the non-oriented electrical steel sheet comprises a black line formed by the elongation of a residual oxide layer in the rolling direction during the cold rolling step.
In paragraph 3, A method for manufacturing a non-oriented electrical steel sheet, wherein the area fraction of the black line of the non-oriented electrical steel sheet is 11% or more and 39% or less.
In paragraph 1, In the above pickling step, A method for manufacturing non-oriented electrical steel sheets, wherein the pickling solution is 7% hydrochloric acid (HCl).
In paragraph 1, In the above pickling step, A method for manufacturing non-oriented electrical steel sheets, wherein the pickling temperature is 85℃.
In paragraph 1, A method for manufacturing a non-oriented electrical steel sheet, wherein the yield strength in the L direction of the above non-oriented electrical steel sheet is 372 MPa or higher.
In paragraph 1, A method for manufacturing a non-oriented electrical steel sheet, wherein the yield strength in the C direction of the above non-oriented electrical steel sheet is 379 MPa or higher.
In paragraph 1, A method for manufacturing a non-oriented electrical steel sheet, wherein the iron loss (W 10/400 ) of the above non-oriented electrical steel sheet is 25.64 W/kg or less.
As a non-oriented electrical steel sheet, In wt%, silicon (Si): 1.8 wt% to 2.8 wt%, manganese (Mn): 0.1 wt% to 0.5 wt%, aluminum (Al): 0.1 wt% to 0.5 wt%, carbon (C): greater than 0 and less than or equal to 0.005 wt%, phosphorus (P): greater than 0 and less than or equal to 0.1 wt%, sulfur (S): greater than 0 and less than or equal to 0.005 wt%, nitrogen (N): greater than 0 and less than or equal to 0.005 wt%, titanium (Ti): greater than 0 and less than or equal to 0.005 wt%, and the remainder being iron (Fe) and unavoidable impurities, The above non-oriented electrical steel sheet includes a black line formed by the residual oxide layer being elongated in the rolling direction during the cold rolling stage, and A non-oriented electrical steel sheet having an area fraction of the above black line of 11% or more and 39% or less.
In Paragraph 10, A non-oriented electrical steel sheet having a yield strength in the L direction of the above non-oriented electrical steel sheet of 372 MPa or more.
In Paragraph 10, A non-oriented electrical steel sheet having a yield strength in the C direction of the above non-oriented electrical steel sheet of 379 MPa or more.
In Paragraph 10, A non-oriented electrical steel sheet having an iron loss (W 10/400 ) of 25.64 W/kg or less.

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. In the case of non-oriented electrical steel sheets used in motors, the automotive industry is shifting toward reducing the production of internal combustion engine vehicles and increasing the production of electric vehicles. Consequently, along with the recent increase in demand for electric vehicles, there is a growing demand for high-efficiency and high-output electrical steel sheets, which are a key component. As part of this effort, attempts are being made to obtain faster rotational speeds than conventional motors by modulating the frequency, such as with BLDC motors. In particular, drive motors used in hybrid and electric vehicles require rotational speeds of 16,000 rpm or higher. In such cases, since the centrifugal force acting on the motor rotor is proportional to the square of the rotational speed, high-speed rotation exceeds the yield strength that ordinary electrical steel sheets can withstand. This causes deformation of the motor, which has a significant impact on its lifespan and durability. Therefore, high-strength materials are required for the rotors of high-speed rotating devices. 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. 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. 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 following embodiments, when a part such as a film, region, or component is described as being on or above another part, it includes not only cases where it is directly on top of another part, but also cases where another film, region, or component is interposed in between. 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, so 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. In the following embodiments, when a membrane, region, component, etc. is described as being connected, it includes cases where the membrane, region, or component is directly connected, or/or cases where other membranes, regions, or components are interposed between the membranes, regions, or components to be indirectly connected. For example, when a membrane, region, component, etc. is described as being electrically connected in this specification, it indicates cases where the membrane, region, or component, etc. are directly electrically connected, and/or cases where other membranes, regions, or components are interposed between them to be indirectly electrically connected. The x-axis, y-axis, and z-axis are not limited to the three axes of an orthogonal coordinate system but can be interpreted in a broader sense that includes them. For example, the x-axis, y-axis, and z-axis may be orthogonal to each other, but they may also refer to different directions that are not orthogonal to each other. FIG. 1 is a flowchart schematically illustrating a method for manufacturing a non-oriented electrical steel sheet accordin