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JP-7857489-B2 - High-performance copper alloy tube and method for manufacturing the same

JP7857489B2JP 7857489 B2JP7857489 B2JP 7857489B2JP-7857489-B2

Inventors

  • メン レイ
  • カオ ジンボ
  • ウー チャンミン
  • トン ビン
  • フー ハイドン
  • フォン ルーミン
  • カオ ケングォ

Assignees

  • 浙江海亮股▲フン▼有限公司

Dates

Publication Date
20260512
Application Date
20251128
Priority Date
20250725

Claims (15)

  1. In terms of mass percentage, the composition includes 0.05% ≤ Sn ≤ 0.6%, 0.08% ≤ Ni < 0.3%, and 0.015% ≤ P ≤ 0.045%, with the remainder being Cu and unavoidable impurities, where f1 = [Sn] + 10 [P] and f2 = [Sn] / [Ni], satisfying 0.5% ≤ f1 ≤ 1.05% and 1 < f2 ≤ 5, where [Sn], [P], and [Ni] are the mass percentages of Sn, P, and Ni content, respectively. A high-performance copper alloy tube characterized by having a single face-centered cubic α-phase, an average grain size of 10 to 25 μm excluding twin grain boundaries, an average grain size of 5 to 20 μm including twin grain boundaries, the total proportion of grain boundaries corresponding to Σ3, Σ9, and Σ27 being ≥ 50%, and the ratio of grain boundaries corresponding to Σ9 and Σ27 to Σ3 being (Σ9 + Σ27) / Σ3 ≥ 3.5%.
  2. The high-performance copper alloy pipe according to claim 1, characterized in that it has a tensile strength of ≥260 MPa, a yield ratio of 0.23 to 0.30, a burst pressure decay rate of ≤10%, and after corrosion for 21 days by repeatedly heating and cooling in an atmosphere of 0.4% formic acid aqueous solution, the maximum corrosion depth of the single pipe is ≤170 μm, and the maximum corrosion depth of the pipe bend is ≤190 μm.
  3. In terms of mass percentage, the composition includes 0.05% ≤ Sn ≤ 0.6%, 0.08% ≤ Ni < 0.3%, and 0.015% ≤ P ≤ 0.045%, with the remainder being Cu and unavoidable impurities, where f1 = [Sn] + 10 [P] and f2 = [Sn] / [Ni], satisfying 0.5% ≤ f1 ≤ 1.05% and 1 < f2 ≤ 5, where [Sn], [P], and [Ni] are the mass percentages of Sn, P, and Ni content, respectively. A high-performance copper alloy tube characterized by having a single face-centered cubic α-phase, an average grain size of 10 to 25 μm excluding twin grain boundaries, an average grain size of 5 to 20 μm including twin grain boundaries, a total proportion of grain boundaries corresponding to Σ3, Σ9, and Σ27 ≥ 68%, and a ratio of grain boundaries corresponding to Σ9 and Σ27 to Σ3 that satisfies (Σ9 + Σ27) / Σ3 ≥ 10%.
  4. The high-performance copper alloy pipe according to claim 3, characterized in that it has a tensile strength of ≥285 MPa, a yield ratio of 0.21 to 0.28, a burst pressure decay rate of ≤5%, and after corrosion for 21 days by repeated cooling and heating in an atmosphere of 0.4% formic acid aqueous solution, the maximum corrosion depth of the single pipe is ≤155 μm, and the maximum corrosion depth of the pipe bend is ≤165 μm.
  5. In terms of mass percentage, the composition includes 0.05% ≤ Sn ≤ 0.6%, 0.08% ≤ Ni < 0.3%, 0.015% ≤ P ≤ 0.045%, 0.001% ≤ Zr < 0.03%, 0.001% ≤ Co < 0.01%, and 0 ≤ B < 0.01%, with the remainder being Cu and unavoidable impurities, where f1 = [Sn] + 10[P] + 10[Zr] and f2 = [Sn] / [Ni], satisfying 0.65% ≤ f1 < 1.15% and 1 < f2 ≤ 5, where [Sn], [P], [Zr], and [Ni] are the mass percentages of Sn, P, Zr, and Ni content, respectively. A high-performance copper alloy tube characterized by having a single face-centered cubic α-phase, an average grain size of 10 to 25 μm excluding twin grain boundaries, an average grain size of 5 to 20 μm including twin grain boundaries, a total proportion of grain boundaries corresponding to Σ3, Σ9, and Σ27 ≥ 60%, and a ratio of grain boundaries corresponding to Σ9 and Σ27 to Σ3 that satisfies (Σ9 + Σ27) / Σ3 ≥ 4.0%.
  6. The high-performance copper alloy pipe according to claim 5, characterized in that it has a tensile strength of ≥275 MPa, a yield ratio of 0.22 to 0.29, a burst pressure decay rate of ≤6%, and after corrosion for 21 days by repeatedly heating and cooling in an atmosphere of 0.4% formic acid aqueous solution, the maximum corrosion depth of the single pipe is ≤165 μm or less, and the maximum corrosion depth of the pipe bend is ≤180 μm.
  7. The high-performance copper alloy tube according to claim 5 or 6, characterized in that 0.001% ≤ B < 0.01%.
  8. The high-performance copper alloy pipe according to claim 7, characterized in that, after corrosion for 21 days by repeatedly heating and cooling in an atmosphere of a 0.4% formic acid aqueous solution, the maximum corrosion depth of the single pipe is ≤ 155 μm, and the maximum corrosion depth of the pipe bend is ≤ 170 μm.
  9. In terms of mass percentage, the composition includes 0.05% ≤ Sn ≤ 0.6%, 0.08% ≤ Ni < 0.3%, 0.015% ≤ P ≤ 0.045%, 0.001% ≤ Zr < 0.03%, 0.001% ≤ Co < 0.01%, and 0 ≤ B < 0.01%, with the remainder being Cu and unavoidable impurities, where f1 = [Sn] + 10[P] + 10[Zr] and f2 = [Sn] / [Ni], satisfying 0.65% ≤ f1 < 1.15% and 1 < f2 ≤ 5, where [Sn], [P], [Zr], and [Ni] are the mass percentages of Sn, P, Zr, and Ni content, respectively. A high-performance copper alloy tube characterized by having a single face-centered cubic α-phase, an average grain size of 10 to 25 μm excluding twin grain boundaries, an average grain size of 5 to 20 μm including twin grain boundaries, a total proportion of grain boundaries corresponding to Σ3, Σ9, and Σ27 ≥ 72%, and a ratio of grain boundaries corresponding to Σ9 and Σ27 to Σ3 that satisfies (Σ9 + Σ27) / Σ3 ≥ 12%.
  10. The high-performance copper alloy pipe according to claim 9, characterized in that it has a tensile strength of ≥295 MPa, a yield ratio of 0.20 to 0.27, a burst pressure decay rate of ≤2%, and after corrosion for 21 days by repeated cooling and heating in an atmosphere of 0.4% formic acid aqueous solution, the maximum corrosion depth of the single pipe is ≤150 μm, and the maximum corrosion depth of the pipe bend is ≤160 μm.
  11. The high-performance copper alloy tube according to claim 9 or 10, characterized in that 0.001% ≤ B < 0.01%.
  12. The high-performance copper alloy pipe according to claim 11, characterized in that, after corrosion for 21 days by repeatedly heating and cooling in an atmosphere of a 0.4% formic acid aqueous solution, the maximum corrosion depth of the single pipe is ≤ 145 μm, and the maximum corrosion depth of the pipe bend is ≤ 155 μm.
  13. A blending and dissolving step in which raw materials are dissolved to match the blending ratio, A continuous casting step in which molten metal is continuously cast to form a billet, A rolling step in which a billet is rolled to obtain a rolled tube, A continuous drawing step to reduce the diameter of the rolled raw tube, A method for manufacturing a high-performance copper alloy tube according to any one of claims 1 to 6, 9, and 10 , characterized by comprising a recrystallization step to obtain a product with target performance by controlling the amount of deformation and annealing parameters.
  14. The method for manufacturing a high-performance copper alloy tube according to claim 13, characterized in that the recrystallization treatment is a single recrystallization process consisting of "block drawing → finished product annealing," the total deformation amount of the block drawing is 80% or more, the temperature of the finished product annealing is 500 to 750°C, and the annealing time is 30 to 150 min.
  15. The recrystallization process is a repeated recrystallization in which a block drawing cycle of "block drawing → annealing" is performed multiple times after one to three passes of block drawing, the total deformation amount of the block drawing in the one to three passes prior to the cycle is ≤72%, the number of "block drawing → annealing" cycles in the multiple "block drawing → annealing" cycles is 3 to 6 times, the deformation amount of block drawing in a single cycle is 25 to 35%, the annealing temperature is 500 to 600°C, and the annealing time is 10 to 70 min, characterized in that the method for manufacturing a high-performance copper alloy tube according to claim 13.

Description

This application relates to the field of alloys, and more particularly to high-performance copper alloy tubes and methods for manufacturing the same. Due to its excellent thermal conductivity, electrical conductivity, workability, and corrosion resistance, copper has become an important material in fields such as electronic communications and advanced thermal management, new energy and power transmission, and high-end equipment manufacturing. Its importance and scope of application continue to improve with technological advancements. Taking the heat exchange field as an example, as a core material for heat exchangers and piping systems in refrigeration and air conditioning, copper materials need not only high processing performance in bending, flaring, expanding, and welding, but also higher strength, in order to meet the increasingly stringent demands for high pressure resistance and thinner walls. Conventional phosphorus-deoxidized copper tubing (TP2) possesses excellent bending, flaring, and expansion properties. By adding a small amount of phosphorus to electrolytic copper, oxygen is removed, improving its ductility, weldability, and corrosion resistance. However, TP2 copper tubing has a low burst pressure and cannot meet the safety requirements in the context of the development of lightweight, thin-walled copper tubing. To address the problem of the insufficient burst pressure of TP2 copper pipes, various high-strength copper pipes have been researched and developed in recent years. However, while the high-strength copper pipes currently under research and development often have high Sn, Zn, and Ni content, and can to some extent meet the burst pressure requirements after thinning, they generally suffer from poor workability and insufficient plastic deformation capacity (specifically, poor bending, flaring, and expansion performance). Patent CN101469961B discloses a copper alloy material containing Sn and P. This material contains 0.1% to 3.0% Sn and 0.005% to 0.1% P, has a tensile strength of 250 MPa or more, and improves the circumferential tensile strength and further enhances the burst pressure of the copper alloy by limiting the proportion of Goss texture and increasing the proportion of small-angle grain boundaries. However, small-angle grain boundaries are essentially dislocation accumulations, and if their content is too high, it intensifies the material's brittleness, reduces its workability, and degrades its cold workability, such as bending, flaring, and pipe expansion. Patent CN107739880A discloses a high-strength copper alloy material containing Ni, Sn, and P. This material contains 0.3–0.7% Ni, 0.2–1.0% Sn, and 0.01–0.07% P, has a tensile strength of 262–290 MPa, can be processed into a joined copper tube using a rolling and welding process, and ensures that no wrinkles or cracks occur in the copper material during the tube bending process by controlling the elongation at break of the copper material to 40%–50%. However, under these conditions, the workability of the copper tube cannot be effectively ensured, the risk of flaring and expansion is extremely high, and its elongation at break is lower than that of TP2 copper tubes. Therefore, in current research and development and application of high-strength copper alloys, achieving a balance between material strength and workability is a technical challenge in the development of copper alloy tubes for heat exchangers. Among the many indicators used to evaluate the performance of copper alloy tubes, the yield ratio is an important indicator for measuring the balance between material strength and workability. Generally, a low yield ratio indicates that the material has both high tensile strength and low yield strength. This results in a material with excellent uniform deformation capacity and low rebound elasticity, facilitating processing deformation while also being able to withstand high fracture stress. Furthermore, it resolves the problem of difficulty in achieving both high strength and excellent workability simultaneously. The yield ratio of TP2 copper tubes is generally 0.30 to 0.35, while the yield ratio of high-strength copper tubes is generally in the range of 0.4 to 0.6. Consequently, high-strength copper tubes are significantly inferior to TP2 copper tubes in performance aspects such as bending, flaring, and bulging. To address the challenge of balancing strength and workability in high-strength copper alloy materials, it is necessary to develop new high-performance copper tubes with high strength and low yield ratio as research and development goals, adapting to the modern trend towards lighter and more compact refrigeration equipment. Furthermore, in applications involving thin-walled copper pipes, the following two technical challenges arise. Firstly, as the wall thickness decreases, the pitting corrosion resistance life is significantly reduced, and the damage becomes more severe as the wall thickness decreases. Secondly, in