High-purity oxygen-free copper wire and preparation method thereof

Abstract

The invention discloses a high-purity oxygen-free copper wire and a preparation method thereof. The high-purity oxygen-free copper wire comprises, by weight, more than or equal to 99.99% of Cu and less than or equal to 0.0005% of O. The tensile strength of the high-purity oxygen-free copper wire is larger than or equal to 375 MPa, the electric conductivity is larger than or equal to 101% IACS, and the percentage elongation after fracture is larger than or equal to 18%. The preparation method of the high-purity oxygen-free copper wire comprises the following steps of vacuum induction melting, cold rolling treatment, primary annealing treatment, continuous drawing, secondary annealing treatment, continuous drawing, third-time annealing treatment, continuous drawing and fourth-time annealing treatment. Compared with the prior art, the high-purity oxygen-free copper wire is high in purity and good in cold and hot processing performance.

Description

Technical Field

[0001] The invention relates to the field of copper wires, and in particular to a high-purity oxygen-free copper wire and a preparation method thereof. Background Art

[0002] High-purity oxygen-free copper wire is widely used in the fields of wires and cables, transformers, generators, semiconductor chip packaging leads, bonding wires, etc. due to its advantages of high purity, low oxygen content, good conductivity, thermal conductivity, machinability and weldability. Among them, the control of purity and oxygen content is the technical difficulty in the preparation of high-purity oxygen-free copper wire.

[0003] Among the methods currently disclosed for preparing high-purity oxygen-free copper wire, upward continuous casting and continuous directional solidification are the most common. For example, the Chinese invention patent "A production process for ultra-fine copper wire" with application number 201210411819.8, its preparation method is: upward continuous casting, continuous extrusion, multi-pass drawing and annealing, to obtain copper wire with purity ≥99.99%, O content ≤0.0005%, and conductivity ≥101% IACS.

[0004] Another example is the Chinese invention patent with application number 202010019880.2, "A method for preparing fatigue-resistant oxygen-free copper wire for cables", whose preparation method is: high-purity copper smelting, directional solidification, three stripping, three continuous extrusions, two rolling, two annealing, and wire drawing to obtain copper wire with a purity of ≥99.99%, O≤0.0005%, and a tensile strength of ≥270MPa, an elongation after break ≥60%, and a conductivity ≥103%IACS.

[0005] Another example is the Chinese invention patent with application number 202310209744.3, "A method for preparing high-purity oxygen-free copper wire by vacuum down-drawing continuous casting", whose preparation method is: vacuum melting, down-drawing continuous casting, surface treatment (skinning), primary drawing, annealing, and secondary drawing to obtain copper wire with a conductivity ≥100% IACS.

[0006] In summary, the process flow of continuous casting-rolling-drawing-annealing-drawing in the above-mentioned prior art has the problems that the continuous casting copper rod is prone to pores and shrinkage, the surface quality is average, and the wire is easily broken in the subsequent wire drawing process. The process flow of continuous directional solidification-rolling-drawing-annealing-drawing, although it combines the columnar single crystal with subsequent plastic processing, has high production efficiency and production cost. Summary of the invention

[0007] The first technical problem to be solved by the present invention is to provide a high-purity oxygen-free copper wire with good cold and hot processing performance in view of the above technical status.

[0008] The second technical problem to be solved by the present invention is to provide a method for preparing high-purity oxygen-free copper wire in view of the above technical status, so that the obtained copper wire has high purity and low production cost.

[0009] The technical solution adopted by the present invention to solve the above-mentioned first technical problem is: a high-purity oxygen-free copper wire, characterized in that it comprises the following components by weight: Cu ≥ 99.99%, O ≤ 0.0005%; the tensile strength of the high-purity oxygen-free copper wire is ≥ 375MPa, the conductivity is ≥ 101% IACS, and the elongation after fracture is ≥ 18%.

[0010] The technical solution adopted by the present invention to solve the above second technical problem is: a method for preparing a high-purity oxygen-free copper wire, characterized in that it comprises the following steps:

[0011] S1. Vacuum induction melting: Put the copper raw material into the melting furnace, add rare earth to keep warm and then perform horizontal continuous casting after the copper raw material is completely melted;

[0012] S2, cold rolling treatment: the ingot obtained in step S1 is subjected to multiple cold rolling processes to obtain a rod billet;

[0013] S3, primary annealing treatment: placing the rod blank obtained in step S2 in a heat preservation furnace for annealing treatment;

[0014] S4, continuous drawing: the rod blank obtained in step S3 is subjected to a multi-pass continuous drawing process;

[0015] S5, secondary annealing treatment: placing the rod blank obtained in step S4 in a heat preservation furnace for annealing treatment;

[0016] S6, continuous drawing: the rod blank obtained in step S5 is subjected to a multi-pass continuous drawing process to obtain a wire blank;

[0017] S7, three-stage annealing treatment: placing the wire blank obtained in step S6 in a heat-insulating furnace for annealing treatment;

[0018] S8, continuous drawing: the wire blank obtained in step S7 is subjected to a multi-pass continuous drawing process to obtain a rod blank;

[0019] S9, fourth annealing treatment: placing the rod blank obtained in step S8 in a heat-insulating furnace for annealing treatment.

[0020] The preparation process is simple to operate and the cost is controllable, and it has good potential for industrial production of high-purity oxygen-free copper wire.

[0021] Preferably, the copper raw material in step S1 is T2 electrolytic copper block.

[0022] Preferably, step S1 is: controlling the vacuum degree before smelting to ≤2.0×10-3Pa, then introducing N2 and maintaining a slight positive pressure in the smelting furnace, adding rare earth element Ce after the T2 electrolytic copper block is completely melted, the mass ratio of Ce to T2 electrolytic copper is (0.065-0.075%):1, and conducting horizontal continuous casting after keeping warm for 10-12 minutes at a temperature of 1100-1140°C, and the speed of horizontal continuous casting is 12-15cm / min to obtain a continuously cast copper rod. By quantitatively adding trace amounts of rare earth element Ce, the matrix of pure copper melt is purified. Ce has a strong ability to bind with O and S in the melt, mainly forming Ce2O3 and CeS, followed by Bi, Pb, and Fe, mainly forming CeBi3, CePb3, and Fe2Ce. The compounds are suspended in the upper layer and surface of the melt to maintain the cleanliness of the melt; thus, the final copper wire is of high purity, with low contents of elements such as O, S, Pb, and Bi, or even does not contain the above elements, so that the high-purity oxygen-free copper wire has excellent hot and cold processing performance.

[0023] Preferably, the cold rolling treatment in step S2 has a single-pass processing amount of 15-20%, and a total deformation amount of 60-80%.

[0024] Preferably, the single-pass processing amount of the continuous drawing in step S4 is 10-20%, and the total deformation amount is 80-90%.

[0025] Preferably, the processing amount of a single pass of the continuous drawing in step S6 is 10-15%, and the total deformation amount is 70-90%.

[0026] Preferably, the single-pass processing amount of the continuous drawing in step S8 is 5-10%, and the total deformation amount is 80-90%.

[0027] Preferably, the step S3 is: placing the rod blank obtained in step S2 in a heat preservation furnace, introducing N2 for atmosphere protection, heating up at a rate of 410-430°C / h, holding at a temperature of 400-450°C, holding for 1-3h, and then cooling with the furnace;

[0028] The step S5 is: placing the rod blank obtained in step S4 in a holding furnace, introducing N2 for atmosphere protection, heating up at a rate of 410-430°C / h, holding at a temperature of 360-400°C, holding for 1-3h, and then cooling with the furnace. N2 can isolate air from the melt, thereby ensuring that no external gas enters the melt, and then obtaining a pure and high-quality cast billet bar by horizontal continuous casting.

[0029] Preferably, the step S7 is: placing the wire blank obtained in step S6 in a holding furnace, introducing N2 for atmosphere protection, heating up at a rate of 410-430°C / h, holding at a temperature of 360-380°C, holding for 3-6h, and then cooling with the furnace;

[0030] The step S9 is: placing the rod blank obtained in step S8 in a heat preservation furnace, introducing N2 for atmosphere protection, heating up at a rate of 350-370°C / h, holding at a temperature of 320-340°C, holding for 4-5h, and then cooling with the furnace.

[0031] Compared with the prior art, the advantages of the present invention are: the copper wire has high purity and low O element content, so it has good cold and hot processing performance; the high-purity oxygen-free copper wire has a tensile strength of ≥375MPa, a conductivity of ≥101%IACS, and an elongation after fracture of ≥18%, and has excellent performance. The high-purity oxygen-free copper wire is not easy to break during reprocessing, and is convenient for production. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below with reference to the embodiments.

[0033] Embodiment 1:

[0034] The preparation steps of the high-purity oxygen-free copper wire of this embodiment are as follows:

[0035] S1 Vacuum induction melting: Place T2 electrolytic copper block into the melting furnace, and the vacuum degree before melting is 2.0×10 - 3 Pa, then N2 is introduced, and a slightly positive pressure is maintained in the furnace. After the T2 electrolytic copper block is completely melted, rare earth element Ce is added, and the mass ratio of Ce to T2 electrolytic copper is 0.065%:1. After being kept at 1100°C for 10 minutes, horizontal continuous casting is performed at a speed of 12 cm / min to obtain a continuously cast copper rod;

[0036] S2 cold rolling treatment: the ingot obtained in step S1 is subjected to multiple cold rolling treatments, the processing amount of each cold rolling treatment is 15%, and the total deformation amount is 60%;

[0037] S3: primary annealing treatment: placing the rod blank obtained in step S2 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating to 400°C at a heating rate of 420°C / h, holding for 1h, and then cooling with the furnace;

[0038] S4 continuous drawing: the rod blank obtained in step S3 is subjected to multiple continuous drawing processes, the processing amount of a single continuous drawing process is 10%, and the total deformation amount is 80%;

[0039] S5 secondary annealing treatment: placing the rod blank obtained in step S4 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating to 360°C at a heating rate of 420°C / h, holding time of 1h, and then cooling with the furnace;

[0040] S6 continuous drawing: the rod blank obtained in step S5 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 10%, and the total deformation amount is 70%;

[0041] S7: tertiary annealing treatment: placing the wire blank obtained in step S6 in a holding furnace, introducing N2 for atmosphere protection, then heating to 360°C at a heating rate of 420°C / h, holding for 3h, and then cooling with the furnace;

[0042] S8 continuous drawing: the wire blank obtained in step S7 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 5%, and the total deformation amount is 80%;

[0043] S9: Four-time annealing treatment: the rod blank obtained in step S8 is placed in a heat-insulating furnace, and N2 is introduced for atmosphere protection. Then, the temperature is increased to 320°C at a heating rate of 360°C / h, and the heat-insulating time is 4h, and then the rod blank is cooled in the furnace.

[0044] The high-purity oxygen-free copper wire obtained in this embodiment has Cu: 99.99%, O: 0.0005% by weight; its tensile strength is 375 MPa, the conductivity is 101% IACS, and the elongation after fracture is 18%.

[0045] Embodiment 2:

[0046] The preparation steps of the high-purity oxygen-free copper wire of this embodiment are as follows:

[0047] S1 Vacuum induction melting: Place T2 electrolytic copper block into the melting furnace, and the vacuum degree before melting is 2.0×10 - 3 Pa, then N2 is introduced, and a slightly positive pressure is maintained in the furnace. After the T2 electrolytic copper block is completely melted, rare earth element Ce is added, and the mass ratio of Ce to T2 electrolytic copper is 0.07%:1. After being kept at 1120°C for 11 minutes, horizontal continuous casting is performed at a speed of 13 cm / min to obtain a continuously cast copper rod;

[0048] S2 cold rolling treatment: the ingot obtained in step S1 is subjected to multiple cold rolling treatments, the processing amount of each cold rolling treatment is 15%, and the total deformation amount is 75%;

[0049] S3: primary annealing treatment: placing the rod blank obtained in step S2 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating to 460°C at a heating rate of 420°C / h, holding for 3h, and then cooling with the furnace;

[0050] S4 continuous drawing: the rod blank obtained in step S3 is subjected to multiple continuous drawing processes, the processing amount of a single continuous drawing process is 15%, and the total deformation amount is 90%;

[0051] S5 secondary annealing treatment: placing the rod blank obtained in step S4 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating to 380°C at a heating rate of 420°C / h, holding for 2h, and then cooling with the furnace;

[0052] S6 continuous drawing: the rod blank obtained in step S5 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of continuous drawing is 12%, and the total deformation amount is 84%;

[0053] S7: tertiary annealing treatment: placing the wire blank obtained in step S6 in a holding furnace, introducing N2 for atmosphere protection, then heating to 380°C at a heating rate of 420°C / h, holding for 4h, and then cooling with the furnace;

[0054] S8 continuous drawing: the wire blank obtained in step S7 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 10%, and the total deformation amount is 80%;

[0055] S9: Four-time annealing treatment: The rod blank obtained in step S8 is placed in a heat-insulating furnace, and N2 is introduced for atmosphere protection. Then, the temperature is increased to 320°C at a heating rate of 360°C / h, and the heat-insulating time is 5h, and then the rod blank is cooled in the furnace.

[0056] The high-purity oxygen-free copper wire obtained in this embodiment has Cu: 99.99%, O: 0.0005% by weight; its tensile strength is 381 MPa, the conductivity is 101.5% IACS, and the elongation after fracture is 18%.

[0057] Embodiment 3:

[0058] The preparation steps of the high-purity oxygen-free copper wire of this embodiment are as follows:

[0059] S1 vacuum induction melting: put T2 electrolytic copper block into the melting furnace, and the vacuum degree before melting is 1.9×10 - 3 Pa, then N2 is introduced, and a slightly positive pressure is maintained in the furnace. After the T2 electrolytic copper block is completely melted, rare earth element Ce is added, and the mass ratio of Ce to T2 electrolytic copper is 0.07%:1. After being kept at 1140°C for 12 minutes, horizontal continuous casting is performed at a speed of 15 cm / min to obtain a continuously cast copper rod;

[0060] S2 cold rolling treatment: the ingot obtained in step S1 is subjected to multiple cold rolling treatments, the processing amount of each cold rolling treatment is 20%, and the total deformation amount is 80%;

[0061] S3: primary annealing treatment: placing the rod blank obtained in step S2 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating to 500°C at a heating rate of 420°C / h, holding time of 3h, and then cooling with the furnace;

[0062] S4 continuous drawing: the rod blank obtained in step S3 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 10%, and the total deformation amount is 90%;

[0063] S5 secondary annealing treatment: placing the rod blank obtained in step S4 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating to 400°C at a heating rate of 420°C / h, holding time of 3h, and then cooling with the furnace;

[0064] S6 continuous drawing: the rod blank obtained in step S5 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 15%, and the total deformation amount is 90%;

[0065] S7: tertiary annealing treatment: placing the wire blank obtained in step S6 in a holding furnace, introducing N2 for atmosphere protection, then heating to 380°C at a heating rate of 420°C / h, holding for 6h, and then cooling with the furnace;

[0066] S8 continuous drawing: the wire blank obtained in step S7 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 10%, and the total deformation amount is 90%;

[0067] S9: Four-time annealing treatment: The rod blank obtained in step S8 is placed in a heat-insulating furnace, and N2 is introduced for atmosphere protection. Then, the temperature is increased to 340°C at a heating rate of 360°C / h, and the heat-insulating time is 5h, and then the rod blank is cooled in the furnace.

[0068] The high-purity oxygen-free copper wire obtained in this embodiment has Cu: 99.993%, O: 0.0004% by weight; its tensile strength is 389 MPa, the conductivity is 101.4% IACS, and the elongation after fracture is 18.5%.

[0069] Embodiment 4:

[0070] The preparation steps of the high-purity oxygen-free copper wire of this embodiment are as follows:

[0071] S1 vacuum induction melting: put T2 electrolytic copper block into the melting furnace, and the vacuum degree before melting is 1.9×10 - 3Pa, then N2 is introduced, and a slightly positive pressure is maintained in the furnace. After the T2 electrolytic copper block is completely melted, rare earth element Ce is added, and the mass ratio of Ce to T2 electrolytic copper is 0.075%:1. After being kept at 1120°C for 12 minutes, horizontal continuous casting is performed at a speed of 15 cm / min to obtain a continuously cast copper rod;

[0072] S2 cold rolling treatment: the ingot obtained in step S1 is subjected to multiple cold rolling treatments, the processing amount of each cold rolling treatment is 15%, and the total deformation amount is 75%;

[0073] S3: primary annealing treatment: placing the rod blank obtained in step S2 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating to 500°C at a heating rate of 420°C / h, holding for 1h, and then cooling with the furnace;

[0074] S4 continuous drawing: the rod blank obtained in step S3 is subjected to multiple continuous drawing processes, the processing amount of a single continuous drawing process is 20%, and the total deformation amount is 80%;

[0075] S5 secondary annealing treatment: placing the rod blank obtained in step S4 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating to 360°C at a heating rate of 420°C / h, holding time for 3h, and then cooling with the furnace;

[0076] S6 continuous drawing: the rod blank obtained in step S5 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 15%, and the total deformation amount is 75%;

[0077] S7: tertiary annealing treatment: placing the wire blank obtained in step S6 in a holding furnace, introducing N2 for atmosphere protection, then heating to 370°C at a heating rate of 420°C / h, holding for 4h, and then cooling with the furnace;

[0078] S8 continuous drawing: the wire blank obtained in step S7 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 5%, and the total deformation amount is 80%;

[0079] S9: Four-time annealing treatment: The rod blank obtained in step S8 is placed in a heat-insulating furnace, and N2 is introduced for atmosphere protection. Then, the temperature is increased to 340°C at a heating rate of 360°C / h, and the heat-insulating time is 4h, and then the rod blank is cooled in the furnace.

[0080] The high-purity oxygen-free copper wire obtained in this embodiment has Cu: 99.995%, O: 0.0005% by weight; its tensile strength is 387 MPa, the conductivity is 101.6% IACS, and the elongation after fracture is 18.5%.

[0081] Embodiment 5:

[0082] The preparation steps of the high-purity oxygen-free copper wire of this embodiment are as follows:

[0083] S1 Vacuum induction melting: Place T2 electrolytic copper block into the melting furnace, and the vacuum degree before melting is 2.0×10 - 3 Pa, then N2 is introduced, and a slightly positive pressure is maintained in the furnace. After the T2 electrolytic copper block is completely melted, rare earth element Ce is added, and the mass ratio of Ce to T2 electrolytic copper is 0.07%:1. After being kept at 1100°C for 10 minutes, horizontal continuous casting is performed at a speed of 13 cm / min to obtain a continuously cast copper rod;

[0084] S2 cold rolling treatment: the ingot obtained in step S1 is subjected to multiple cold rolling treatments, the processing amount of each cold rolling treatment is 15%, and the total deformation amount is 75%;

[0085] S3: primary annealing treatment: placing the rod blank obtained in step S2 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating the temperature to 450°C at a heating rate of 420°C / h, holding the temperature for 3h, and then cooling the rod blank with the furnace;

[0086] S4 continuous drawing: the rod blank obtained in step S3 is subjected to multiple continuous drawing processes, the processing amount of a single continuous drawing process is 10%, and the total deformation amount is 80%;

[0087] S5 secondary annealing treatment: placing the rod blank obtained in step S4 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating to 400°C at a heating rate of 420°C / h, holding time of 2h, and then cooling with the furnace;

[0088] S6 continuous drawing: the rod blank obtained in step S5 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 10%, and the total deformation amount is 90%;

[0089] S7: tertiary annealing treatment: placing the wire blank obtained in step S6 in a holding furnace, introducing N2 for atmosphere protection, then heating to 370°C at a heating rate of 420°C / h, holding for 5h, and then cooling with the furnace;

[0090] S8 continuous drawing: the wire blank obtained in step S7 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 5%, and the total deformation amount is 90%;

[0091] S9: Four-time annealing treatment: The rod blank obtained in step S8 is placed in a heat-insulating furnace, and N2 is introduced for atmosphere protection. Then, the temperature is increased to 320°C at a heating rate of 360°C / h, and the heat-insulating time is 5h, and then the rod blank is cooled in the furnace.

[0092] The high-purity oxygen-free copper wire obtained in this embodiment has Cu: 99.99%, O: 0.0005% by weight; its tensile strength is 379 MPa, the conductivity is 101.2% IACS, and the elongation after fracture is 19%.

[0093] Embodiment 6:

[0094] The preparation steps of the high-purity oxygen-free copper wire of this embodiment are as follows:

[0095] S1 Vacuum induction melting: Place T2 electrolytic copper block into the melting furnace, and the vacuum degree before melting is 2.0×10 - 3 Pa, then N2 is introduced, and a slightly positive pressure is maintained in the furnace. After the T2 electrolytic copper block is completely melted, rare earth element Ce is added, and the mass ratio of Ce to T2 electrolytic copper is 0.065%:1. After being kept at 1120°C for 10 minutes, horizontal continuous casting is performed at a speed of 12 cm / min to obtain a continuously cast copper rod;

[0096] S2 cold rolling treatment: the ingot obtained in step S1 is subjected to multiple cold rolling treatments, the processing amount of each cold rolling treatment is 20%, and the total deformation amount is 80%;

[0097] S3: primary annealing treatment: placing the rod blank obtained in step S2 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating to 400°C at a heating rate of 420°C / h, holding for 3h, and then cooling with the furnace;

[0098] S4 continuous drawing: the rod blank obtained in step S3 is subjected to multiple continuous drawing processes, the processing amount of a single continuous drawing process is 20%, and the total deformation amount is 80%;

[0099] S5 secondary annealing treatment: placing the rod blank obtained in step S4 in a heat preservation furnace, introducing N2 for atmosphere protection, then heating to 360°C at a heating rate of 420°C / h, holding time for 3h, and then cooling with the furnace;

[0100] S6 continuous drawing: the rod blank obtained in step S5 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 15%, and the total deformation amount is 90%;

[0101] S7: tertiary annealing treatment: placing the wire blank obtained in step S6 in a holding furnace, introducing N2 for atmosphere protection, then heating to 360°C at a heating rate of 420°C / h, holding for 6h, and then cooling with the furnace;

[0102] S8 continuous drawing: the wire blank obtained in step S7 is subjected to a multi-pass continuous drawing process, the processing amount of a single pass of the continuous drawing is 10%, and the total deformation amount is 80%;

[0103] S9: Four-time annealing treatment: the rod blank obtained in step S8 is placed in a heat-insulating furnace, and N2 is introduced for atmosphere protection. Then, the temperature is increased to 330°C at a heating rate of 360°C / h, and the heat-insulating time is 5h, and then the rod blank is cooled in the furnace.

[0104] The high-purity oxygen-free copper wire obtained in this embodiment has Cu: 99.99%, O: 0.0005% by weight; its tensile strength is 383 MPa, the conductivity is 101.8% IACS, and the elongation after fracture is 18.5%.

Claims

1. A high-purity oxygen-free copper wire, characterized in that: The invention comprises the following components in weight: Cu≥99.99%, O≤0.0005%; the tensile strength of the high-purity oxygen-free copper wire is ≥375MPa, the conductivity is ≥101%IACS, and the elongation after fracture is ≥18%.

2. A method for preparing the high-purity oxygen-free copper wire according to claim 1, characterized in that: The following steps are involved: S1. Vacuum induction melting: Put the copper raw material into the melting furnace, add rare earth to keep warm and then perform horizontal continuous casting after the copper raw material is completely melted; S2, cold rolling treatment: the ingot obtained in step S1 is subjected to multiple cold rolling processes to obtain a rod billet; S3, primary annealing treatment: placing the rod blank obtained in step S2 in a heat preservation furnace for annealing treatment; S4, continuous drawing: the rod blank obtained in step S3 is subjected to a multi-pass continuous drawing process; S5, secondary annealing treatment: placing the rod blank obtained in step S4 in a heat preservation furnace for annealing treatment; S6, continuous drawing: the rod blank obtained in step S5 is subjected to multiple continuous drawing processes to obtain a wire blank; S7, three-stage annealing treatment: placing the wire blank obtained in step S6 in a heat preservation furnace for annealing treatment; S8, continuous drawing: the wire blank obtained in step S7 is subjected to multiple continuous drawing processes to obtain a rod blank; S9, fourth annealing treatment: placing the rod blank obtained in step S8 in a heat-insulating furnace for annealing treatment.

3. The method for preparing high-purity oxygen-free copper wire according to claim 2, characterized in that: The copper raw material in step S1 is T2 electrolytic copper block.

4. The method for preparing high-purity oxygen-free copper wire according to claim 3, characterized in that: The step S1 is to control the vacuum degree before smelting to be ≤2.0×10 -3 Pa, then N2 is introduced, and a slight positive pressure is maintained in the smelting furnace. After the T2 electrolytic copper block is completely melted, rare earth element Ce is added. The mass ratio of Ce to T2 electrolytic copper is (0.065-0.075%):

1. After keeping warm for 10-12 minutes at 1100-1140°C, horizontal continuous casting is carried out at a speed of 12-15 cm / min to obtain a continuously cast copper rod.

5. The method for preparing high-purity oxygen-free copper wire according to claim 2, characterized in that: The cold rolling treatment in step S2 has a single-pass processing amount of 15-20%, and a total deformation amount of 60-80%.

6. The method for preparing a high-purity oxygen-free copper wire according to claim 2, characterized in that: The continuous drawing in step S4 has a single-pass processing amount of 10-20%, and a total deformation amount of 80-90%.

7. The method for preparing a high-purity oxygen-free copper wire according to claim 2, characterized in that: The continuous drawing in step S6 has a single-pass processing amount of 10-15%, and a total deformation amount of 70-90%.

8. The method for preparing a high-purity oxygen-free copper wire according to claim 2, characterized in that: The continuous drawing in step S8 has a single-pass processing amount of 5-10%, and a total deformation amount of 80-90%.

9. The method for preparing a high-purity oxygen-free copper wire according to claim 2, characterized in that: The step S3 is: placing the rod blank obtained in step S2 in a heat preservation furnace, introducing N2 for atmosphere protection, heating up at a rate of 410-430°C / h, holding at a temperature of 400-450°C, holding for 1-3h, and then cooling with the furnace; The step S5 is: placing the rod blank obtained in step S4 in a heat preservation furnace, introducing N2 for atmosphere protection, heating up at a rate of 410-430°C / h, holding at a temperature of 360-400°C, holding for 1-3h, and then cooling with the furnace.

10. The method for preparing a high-purity oxygen-free copper wire according to claim 2 or 9, characterized in that: The step S7 is: placing the wire blank obtained in step S6 in a holding furnace, introducing N2 for atmosphere protection, heating up at a rate of 410-430°C / h, holding at a temperature of 360-380°C, holding for 3-6h, and then cooling with the furnace; The step S9 is: placing the rod blank obtained in step S8 in a heat preservation furnace, introducing N2 for atmosphere protection, heating up at a rate of 350-370°C / h, holding at a temperature of 320-340°C, holding for 4-5h, and then cooling with the furnace.