Search

KR-20260066951-A - WIRE ROD, MANUFACTURING METHOD OF WIRE ROD, FASTENING PARTS AND MANUFACTURING METHOD OF FASTENING PARTS

KR20260066951AKR 20260066951 AKR20260066951 AKR 20260066951AKR-20260066951-A

Abstract

A wire rod according to one embodiment of the present invention comprises 0.10 to 0.50 wt% carbon (C), 0.10 to 0.50 wt% silicon (Si), 0.50 to 1.20 wt% manganese (Mn), 0.03 wt% or less phosphorus (P) (excluding 0), 0.03 wt% or less sulfur (S) (excluding 0), 0.05 to 1.00 wt% chromium (Cr), 0.05 wt% or less molybdenum (Mo) (excluding 0), 0.005 to 0.050 wt% aluminum (Al), 0.015 to 0.050 wt% titanium (Ti), 0.0005 to 0.0050 wt% boron (B), 0.01 wt% or less nitrogen (N) (excluding 0), and the remainder being iron (Fe) and other unavoidable impurities.

Inventors

  • 이규호
  • 임재한
  • 김영부
  • 노현배
  • 정경태

Assignees

  • 현대제철 주식회사

Dates

Publication Date
20260512
Application Date
20241105

Claims (18)

  1. A wire rod comprising 0.10 to 0.50 wt% carbon (C), 0.10 to 0.50 wt% silicon (Si), 0.50 to 1.20 wt% manganese (Mn), 0.03 wt% or less phosphorus (P) (excluding 0), 0.03 wt% or less sulfur (S) (excluding 0), 0.05 to 1.00 wt% chromium (Cr), 0.05 wt% or less molybdenum (Mo) (excluding 0), 0.005 to 0.050 wt% aluminum (Al), 0.015 to 0.050 wt% titanium (Ti), 0.0005 to 0.0050 wt% boron (B), 0.01 wt% or less nitrogen (N) (excluding 0), and the remainder being iron (Fe) and other unavoidable impurities.
  2. In Article 1, Wire satisfying Equation 1 below: [Equation 1] K1 = (0.5×Al + 0.3×Ti-N)×B×100,000 ≥ 1.0 In Equation 1, Al, Ti, N, and B represent the content of aluminum, titanium, nitrogen, and boron, respectively.
  3. In Article 2, Wire satisfying Equation 2 below: [Equation 2] K2 = 100×(P+S)/K1 ≤ 1.0 In Equation 2, P and S represent the phosphorus content and sulfur content, respectively.
  4. In Paragraph 3, The above wire has a limit upsetting rate of 90% in the upsetting test, Seonjae.
  5. (a) a molten metal preparation step for producing molten steel by melting raw materials; (b) a continuous casting step for manufacturing semi-finished products; and (c) wire rod rolling step for hot rolling semi-finished products; Includes, The wire rod that has undergone the above (c) wire rod rolling step is, A method for manufacturing a wire rod comprising carbon (C) 0.10 to 0.50 wt%, silicon (Si) 0.10 to 0.50 wt%, manganese (Mn) 0.50 to 1.20 wt%, phosphorus (P) 0.03 wt% or less (excluding 0), sulfur (S) 0.03 wt% or less (excluding 0), chromium (Cr) 0.05 to 1.00 wt%, molybdenum (Mo) 0.05 wt% or less (excluding 0), aluminum (Al) 0.005 to 0.050 wt%, titanium (Ti) 0.015 to 0.050 wt%, boron (B) 0.0005 to 0.0050 wt%, nitrogen (N) 0.01 wt% or less (excluding 0), and the remainder being iron (Fe) and other unavoidable impurities.
  6. In Article 5, The wire rod that has undergone the above (c) wire rod rolling step is, Method for manufacturing a wire satisfying the following Equation 1: [Equation 1] K1 = (0.5×Al + 0.3×Ti-N)×B×100,000 ≥ 1.0 In Equation 1, Al, Ti, N, and B represent the content of aluminum, titanium, nitrogen, and boron, respectively.
  7. In Article 6, The wire rod that has undergone the above (c) wire rod rolling step is, Method for manufacturing a wire satisfying the following Equation 2: [Equation 2] K2 = 100×(P+S)/K1 ≤ 1.0 In Equation 2, P and S represent the phosphorus content and sulfur content, respectively.
  8. In Article 7, A method for manufacturing a wire rod, comprising the step of (d) drawing the wire rod that has undergone the above (c) wire rod rolling step.
  9. In Article 8, The wire rod that has undergone the above (d) fresh step is, Limit of the upsetting test, where the upsetting rate exceeds 90%, Method for manufacturing wire.
  10. Manufactured using a wire rod comprising 0.10 to 0.50 wt% carbon (C), 0.10 to 0.50 wt% silicon (Si), 0.50 to 1.20 wt% manganese (Mn), 0.03 wt% or less phosphorus (P) (excluding 0), 0.03 wt% or less sulfur (S) (excluding 0), 0.05 to 1.00 wt% chromium (Cr), 0.05 wt% or less molybdenum (Mo) (excluding 0), 0.005 to 0.050 wt% aluminum (Al), 0.015 to 0.050 wt% titanium (Ti), 0.0005 to 0.0050 wt% boron (B), 0.01 wt% or less nitrogen (N) (excluding 0), and the remainder being iron (Fe) and other unavoidable impurities, The tensile strength is 800 MPa or higher, and elongation of 10% or more, Fastening parts.
  11. In Article 10, The above wire is a fastening component satisfying the following Equation 1: [Equation 1] K1 = (0.5×Al + 0.3×Ti-N)×B×100,000 ≥ 1.0 In Equation 1, Al, Ti, N, and B represent the content of aluminum, titanium, nitrogen, and boron, respectively.
  12. In Article 11, The above wire is a fastening component satisfying the following Equation 2: [Equation 2] K2 = 100×(P+S)/K1 ≤ 1.0 In Equation 2, P and S represent the phosphorus content and sulfur content, respectively.
  13. In Article 12, The above wire has a limit upsetting rate of 90% in the upsetting test, Fastening parts.
  14. (S1) wire manufacturing step for preparing wire; (S2) cold heading step of manufacturing an intermediate product including a flange portion and a body portion extending from the flange portion using the above wire; A heat treatment step (S3) for heat treating the above intermediate product; Includes, The above wire is, Carbon (C) 0.10 to 0.50 wt%, Silicon (Si) 0.10 to 0.50 wt%, Manganese (Mn) 0.50 to 1.20 wt%, Phosphorus (P) 0.03 wt% or less (excluding 0), Sulfur (S) 0.03 wt% or less (excluding 0), Chromium (Cr) 0.05 to 1.00 wt%, Molybdenum (Mo) 0.05 wt% or less (excluding 0), Aluminum (Al) 0.005 to 0.050 wt%, Titanium (Ti) 0.015 to 0.050 wt%, Boron (B) 0.0005 to 0.0050 wt%, Nitrogen (N) 0.01 wt% or less (excluding 0), and the remainder comprising Iron (Fe) and other unavoidable impurities, Method for manufacturing fastening components.
  15. In Article 14, The above wire is a method for manufacturing a fastening component satisfying the following formula 1. [Equation 1] K1 = (0.5×Al + 0.3×Ti-N)×B×100,000 ≥ 1.0 In Equation 1, Al, Ti, N, and B represent the content of aluminum, titanium, nitrogen, and boron, respectively.
  16. In Article 15, The above wire is a method for manufacturing a fastening component satisfying the following Equation 2. [Equation 2] K2 = 100×(P+S)/K1 ≤ 1.0 In Equation 2, P and S represent the phosphorus content and sulfur content, respectively.
  17. In Article 16, The above wire is, Limit of the upsetting test, where the upsetting rate exceeds 90%, Method for manufacturing fastening components.
  18. In Article 14, The above (S3) heat treatment step is, A first heat treatment step (S3-1) of heat-treating the above semi-finished product at 850 to 950℃; and A second heat treatment step (S3-2) of heat-treating the above semi-finished product at 450 to 500℃; including, Method for manufacturing fastening components.

Description

Wire rod, manufacturing method of wire rod, fastening parts and manufacturing method of fastening parts {WIRE ROD, MANUFACTURING METHOD OF WIRE ROD, FASTENING PARTS AND MANUFACTURING METHOD OF FASTENING PARTS} The present invention relates to a wire rod and a method for manufacturing a wire rod, and more specifically, to a wire rod having excellent cold heading properties and a method for manufacturing a wire rod. As the lightweighting of automotive parts becomes required, there is a continuous demand for higher strength in automotive bolts. These automotive bolts can be manufactured by forming wire rods into part shapes through a cold heading process, followed by a quenching and tempering process. In particular, the cold heading process is widely used because, compared to the hot working method, it allows for the omission of the heat treatment process, which is advantageous in terms of unit cost and productivity. However, since the cold heading process varies the pressure applied to the material depending on the shape of the part, it can cause localized cracks depending on the quality of the wire. For example, in automotive bolts, the flange portion is subject to a relatively higher amount of deformation compared to the body portion, so there is a high possibility of cracking. To improve the cracking problem in the flange section, a technology has been proposed to increase toughness by adding nickel (Ni); however, there is a problem in that the manufacturing cost increases due to the addition of nickel (Ni), an expensive metal. As another solution, a technique for controlled rolling at relatively low temperatures has been proposed, but it has the problem of increasing the defect rate or causing equipment damage due to the increased rolling load. Meanwhile, wire rods generally used for automotive bolts are manufactured from chromium (Cr)-molybdenum (Mo) alloys to ensure hardenability and strength. However, since chromium (Cr) and molybdenum (Mo) are also expensive alloying elements, there is a problem in that manufacturing costs increase. Through the present invention, the inventors intend to propose a wire rod having excellent strength while lowering manufacturing costs by replacing expensive alloying elements, and a method for manufacturing the wire rod. FIG. 1 is a flowchart illustrating a method for manufacturing a wire rod according to one embodiment of the present invention. Figure 2 is a detailed flowchart of the wire rod rolling step shown in Figure 1. Figure 3 is a detailed flowchart of the fresh step shown in Figure 1. FIG. 4 is a flowchart illustrating a method for manufacturing a fastening component according to one embodiment of the present invention. Figures 5 and 6 are drawings illustrating the upsetting test shown in Table 2. 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 may be embodied in various different forms and 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 their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. Unless otherwise specified, the notation 'A ~ B' for numerical values A and B shall mean 'A or greater, B or less'. In such notation, if a unit is attached only to numerical value B, that unit shall also apply to numerical value A. Hereinafter, embodiments of the present invention will be described in detail. Seonjae A wire rod according to one embodiment of the present invention comprises 0.10 to 0.50 wt%