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JP-2026514478-A - Low coercivity wire and method for manufacturing the same

JP2026514478AJP 2026514478 AJP2026514478 AJP 2026514478AJP-2026514478-A

Abstract

This invention discloses a low-coercivity wire containing Fe and unavoidable impurities, and further contains the following chemical elements as expressed in mass percentages: C: 0 < C ≤ 0.003%, Si: Si ≤ 0.01%, Mn: 0.1–0.2%, Al: 0.30–0.45%, O: 0.0015–0.0035%, N: 0.001–0.003%, and Ca: 0.0005–0.0015%. Accordingly, this invention also discloses a method for manufacturing the above-mentioned wire. This invention makes it possible to obtain a wire with low coercivity through rational chemical composition design and microstructure control.

Inventors

  • 姚 贊
  • 余 子 權
  • 黄 宗 澤
  • 劉 耀 宗

Assignees

  • 宝山鋼鉄股▲分▼有限公司

Dates

Publication Date
20260511
Application Date
20240419
Priority Date
20230423

Claims (13)

  1. A low coercivity wire containing Fe and unavoidable impurities, further 0 < C ≤ 0.003%, Si ≤ 0.01%, Mn: 0.1–0.2%, Al: 0.30–0.45%, O: 0.0015–0.0035%, N: 0.001–0.003%, Ca: 0.0005–0.0015% A low-coercivity wire characterized by containing each chemical element as indicated by its mass percentage content.
  2. The mass percentage content of each chemical element is 0 < C ≤ 0.003%, Si ≤ 0.01%, Mn: 0.1–0.2%, Al: 0.30–0.45%, O: 0.0015–0.0035%, N: 0.001–0.003%, Ca: 0.0005–0.0015%, The low coercivity wire material according to claim 1, characterized in that the remainder is Fe and other unavoidable impurities.
  3. The low coercivity wire according to claim 1, characterized in that, among other unavoidable impurities, Ti ≤ 0.003%, P ≤ 0.015%, and S ≤ 0.008%.
  4. The mass percentage content of that chemical element is (Al + 100 Ca) / (Ti + N) ≥ 85. Mn/S ≥ 20, The low coercivity wire according to claim 3, characterized in that it satisfies at least one of the following items, and each chemical element in the formula is replaced with the numerical value before the percentage sign of the mass percentage content of the corresponding chemical element.
  5. The low-coercivity wire according to claim 1, characterized in that the ferrite crystal grain size in the low-coercivity wire is 200 to 800 μm.
  6. The low-coercivity wire according to claim 1, characterized in that the size of the aluminum oxide and aluminum carbonitride precipitates in the low-coercivity wire is 3 μm or less.
  7. The low-coercivity wire material according to claim 1, characterized in that its coercivity is 25 A/m or less.
  8. A method for manufacturing a low coercivity wire according to any one of claims 1 to 7, (1) Smelting, (2) Continuous casting, (3) Initial rolling, (4) Heating: Heat to 900-1150°C and keep warm for 1.5-2.5 hours. (5) Wire rod rolling, (6) Cooling by a Stermore fan, (7) Pull out the wire rod, (8) Annealing: A manufacturing method characterized by including the step of annealing at a heating temperature of 870 to 910°C, holding time of 1 to 2 hours, and then cooling to 500°C or below at a cooling rate of 50°C/h or less.
  9. The manufacturing method according to claim 8, characterized in that, in the initial rolling step, the billet or slab is heated to 1100 to 1250°C, and then rolled into small billets of 140 to 220 mm.
  10. The manufacturing method according to claim 8, characterized in that the rolling speed is controlled to 20 to 110 m/s during the wire rod rolling step.
  11. The manufacturing method according to claim 8, characterized in that, in the wire rod rolling step, the inlet temperature of the finishing rolling mill group is controlled to 900 to 980°C, the inlet temperature of the diameter-reducing/constant diameter rolling mill group is controlled to 900 to 980°C, and the discharge temperature is controlled to 890 to 960°C.
  12. The manufacturing method according to claim 8, characterized in that, during the cooling step using a Stermore fan, the airflow of the F1 to F3 fans in the Stermore fan group is controlled to 0 to 50%.
  13. The manufacturing method according to claim 8, characterized in that the wire rod drawing step controls the drawing reduction ratio to 10 to 30%.

Description

This invention relates to steel materials and methods for manufacturing the same, and more particularly to wire rods and methods for manufacturing the same. Soft magnetic materials are materials in which magnetization primarily occurs at magnetic field strengths H of 1000 A/m or less, possessing low coercivity and high permeability. Soft magnetic materials are easily magnetized and easily demagnetized. Electromagnetic pure iron is a typical example of a soft magnetic material. As industries such as electronics and telecommunications develop rapidly, the application fields of electromagnetic pure iron continue to expand, and demand is rapidly increasing. The main magnetic properties of electromagnetic pure iron include coercivity, coercivity aging increase, maximum permeability, and maximum magnetic induction intensity. Of these, the magnitude of the maximum magnetic induction intensity depends on the material's composition, and the corresponding physical state is one in which the magnetization vectors within the material are neatly arranged. This is the number of magnetic field lines passing through a unit cross-sectional area of the iron core, also called magnetic flux density, representing the material's magnetization ability, and its unit is T. Coercivity is a quantity indicating the ease with which a material is magnetized, and it depends on the material's composition and defects (impurities, stress, etc.). Permeability is the ratio of B to H corresponding to any point on the magnetic hysteresis loop, and is closely related to the material structure and the operating state of the device. Coercivity is the case when, after a magnetic material has saturated magnetized, its magnetic induction intensity B does not return to zero even when the external magnetic field returns to zero, and the magnetic induction intensity can only be returned to zero by applying a magnetic field of a certain magnitude in the opposite direction to the original magnetization field. This magnetic field is called the coercive field, or coercivity. The lower the coercivity of soft magnetic materials, the easier they are to magnetize and demagnetize. In practical applications, this allows for faster power parameter conversion in circuits and improved response speed; therefore, reducing the coercivity of electromagnetic pure iron materials is desirable. For example, in a Chinese patent document titled "Low Coercivity, High Permeability Electromagnetic Pure Iron Cold-Rolled Thin Sheet Material," publication number CN100457385C, published on February 4, 2009, a component ratio of C ≤ 0.010%, Si ≤ 0.10%, Mn ≤ 0.20%, P ≤ 0.015%, S ≤ 0.010%, Al = 0.50% to 0.80%, [O], [N] < 40 ppm, electrolytic inclusions < 60 ppm, with the remainder being Fe, was adopted to obtain a DT4C-grade product with low coercivity and high permeability. The following provides specific examples to further interpret and explain the low-coercivity wire and its manufacturing method according to the present invention. However, this interpretation and explanation is not intended to unduly limit the technical solutions of the present invention. Examples 1-10 and Comparative Examples 1-3 The low-coercivity wires of Examples 1 to 10 were all manufactured using the following steps. (1) After electric furnace smelting, LF furnace refining and RH degassing treatment were performed to control the P element content in the steel to 0.015% or less, the S element content to 0.008% or less, and the Ti element content to 0.003% or less, while controlling the O content to 0.0015–0.0035% and the N content to 0.001–0.003%. After refining, calcium wire was supplied to control the Ca content in the steel to 0.0005–0.0015%. (2) Casting was performed using a continuous bloom casting machine under argon gas protection to obtain continuous cast blooms or slabs. The bloom size was 450 mm or less, and the slab thickness was 400 mm or less. By adjusting the drawing speed, cooling, and end-end reduction parameters during the continuous casting process, the uniform distribution of precipitates was controlled, and elemental segregation in the center of the billet was reduced. The chemical composition of the blooms or slabs is shown in Table 1. (3) The slab was cut longitudinally to obtain billets of size 400 mm or less. Of these, 400 mm billets were used in Examples 6-7, 350 mm billets in Examples 8-9, and 250 mm billets in Example 10. After cutting the continuous casting bloom or slab into billets and heating them to 1100-1250°C, they were rolled into small billets of 140-220 mm. The small billets underwent eddy current testing, magnetic particle testing, grinding, additional magnetic particle testing, and grinding to remove defects such as cracks and depressions from the ingot surface, with defect depths of 0.5 mm or less. (4) The small billets were heated to 900–1150°C, for example, 950–1150°C, and kept warm for 1.5–2.5 hours. (5) The wire rods were rolled, with the rolling speed controlled to 2