Copper-magnesium alloy wire and preparation method thereof

Abstract

The invention relates to the technical field of alloy materials, and discloses a copper-magnesium alloy wire and a preparation method thereof.The copper-magnesium alloy wire comprises, by mass, 0.1%-0.15% of magnesium, 0.007%-0.02% of phosphorus, 0.002%-0.03% of rare earth elements and the balance copper and inevitable impurities. By adding a trace amount of phosphorus and rare earth elements, the ingot casting quality and the solution strengthening effect of the alloy can be effectively improved, and the strength of the copper-magnesium alloy is improved while high conductivity is kept.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and particularly to a copper-magnesium alloy wire and a preparation method thereof. Background Art

[0002] A high-voltage wire harness refers to a wire harness connecting an engine, a battery, and other electrical devices. Among them, copper-magnesium alloy is widely used as a high-speed rail contact wire, a high-voltage wire harness of new energy vehicles, etc. due to its high mechanical strength and good electrical conductivity. However, if the magnesium content in the copper-magnesium alloy is too high, the fluidity of the copper alloy will be reduced, thereby reducing the ingot quality, while too little magnesium content will affect the solution strengthening effect of the copper alloy. Therefore, how to balance the ingot quality and the solution strengthening effect of the copper-magnesium alloy is an urgent problem to be solved. Summary of the Invention

[0003] In view of this, the present invention provides a copper-magnesium alloy wire and a preparation method thereof to solve the problem that the existing copper-magnesium alloy cannot effectively balance the ingot quality and the solution strengthening effect.

[0004] To solve the above technical problems, the present invention adopts the following technical solutions:

[0005] On the one hand, the present invention provides a copper-magnesium alloy wire, which is composed of copper, magnesium, phosphorus, rare earth elements, and inevitable impurities. By mass percentage, the content of magnesium is 0.1-0.15%, and the content of phosphorus is 0.007-0.02%.

[0006] Preferably, the content of the rare earth element is 0.002-0.03%.

[0007] Preferably, the rare earth element includes one or more of cerium, lanthanum, praseodymium, and neodymium.

[0008] Preferably, the rare earth element is cerium.

[0009] Preferably, the content of magnesium is 0.12-0.15%.

[0010] Preferably, the content of phosphorus is 0.007-0.01%.

[0011] On the other hand, the present invention provides a preparation method of the copper-magnesium alloy wire according to any one of the above, including the following steps:

[0012] (1) Sealing magnesium, a copper-phosphorus master alloy, and a copper-rare earth element master alloy in a copper tube to obtain a sealed copper tube;

[0013] (2) Melting copper to obtain a copper melt;

[0014] (3) Insert the sealed copper tube into the molten copper. After the magnesium, copper-phosphorus master alloy, and copper-rare earth element master alloy are melted, lift the sealed copper tube and remove it to obtain an alloy melt;

[0015] (4) Cast the alloy melt into an ingot, and then successively perform hot extrusion, first drawing, heat treatment, and second drawing on the ingot to obtain a copper-magnesium alloy wire.

[0016] Preferably, the purity of the magnesium is ≥99.9%.

[0017] Preferably, the purity of the copper is ≥99.9%.

[0018] Preferably, the mass content of phosphorus in the copper-phosphorus master alloy is 13-15%.

[0019] Preferably, the mass content of rare earth elements in the copper-rare earth element master alloy is 15-25%.

[0020] Preferably, the melting is carried out under a protective atmosphere.

[0021] Preferably, the pressure of the melting is 0.04-0.06 MPa.

[0022] Preferably, in step (3), the temperature of the molten copper is maintained at 1150-1300 °C.

[0023] Preferably, the insertion speed is 0.5-1 m / s.

[0024] Preferably, the casting temperature is 1150-1300 °C.

[0025] Preferably, the temperature of the hot extrusion is 500-600 °C.

[0026] Preferably, the heat treatment is to keep it at 200-260 °C for 2 h, and then perform quenching treatment.

[0027] Preferably, both the first drawing and the second drawing are cold deformation drawing, and the drawing rates of the first drawing and the second drawing are independently 2-4 m / min.

[0028] Preferably, the ingot is cylindrical, the diameter of the ingot is 18-22 mm, the diameter of the ingot after the hot extrusion treatment is 8-12 mm, the diameter of the ingot after the first drawing treatment is 4-8 mm, and the diameter of the copper-magnesium alloy wire after the second drawing treatment is 0.1-0.15 mm.

[0029] The present invention provides a copper-magnesium alloy wire and a preparation method thereof. Compared with the prior art, its beneficial effects are as follows:

[0030] Based on the copper-magnesium alloy, trace amounts of phosphorus and rare earth elements are added. Among them, the rare earth elements can effectively refine the grains of the alloy, optimize the microstructure of the alloy, and remove impurities in the alloy, thereby achieving the effect of improving the quality of the ingot; phosphorus can effectively improve the solution strengthening effect of the alloy, thereby improving the strength and hardness of the copper-magnesium alloy. At the same time, by adding phosphorus, the fluidity during the melting process of the copper alloy and the welding performance of the alloy can be improved simultaneously under specific ratios. Specific embodiments

[0031] The present invention will be described below through specific embodiments. Those skilled in the art can understand that the following specific embodiments are only for the purpose of illustration and do not limit the scope of the present invention in any way. In addition, in the following embodiments, unless otherwise specified, the reagents and equipment used are commercially available. If the specific processing conditions and methods are not clearly described in the following embodiments, the conditions and methods known in the art can be used for processing.

[0032] In one aspect of the present invention, a copper-magnesium alloy wire is proposed. The copper-magnesium alloy wire is composed of copper, magnesium, phosphorus, rare earth elements, and inevitable impurities. By mass percentage, the content of magnesium is 0.1-0.15%, and the content of phosphorus is 0.007-0.02%.

[0033] In some embodiments of the present invention, by mass percentage, the copper-magnesium alloy wire includes 0.1-0.15% magnesium, preferably 0.12-0.15%, for example, it can be 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, etc.; the copper-magnesium alloy wire includes 0.007-0.02% phosphorus, preferably 0.007-0.01%, for example, it can be 0.007%, 0.01%, 0.015%, 0.02%, etc.

[0034] In some embodiments of the present invention, the content of the rare earth elements is 0.002-0.03%, for example, it can be 0.002%, 0.005%, 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, etc.; the rare earth elements include one or more of cerium, lanthanum, praseodymium, and neodymium, preferably cerium. By adding rare earth elements, the grains of the alloy can be effectively refined, the microstructure of the alloy can be optimized, and impurities in the alloy can be removed, thereby achieving the effect of improving the quality of the ingot.

[0035] It should be noted that the contents of magnesium, phosphorus, and rare earth elements in the present invention only need to be within the above-defined ranges, and no special limitation is imposed on the combination methods of their different contents, and they can be adaptively adjusted according to actual situations.

[0036] In another aspect of the present invention, there is provided a method for preparing a copper-magnesium alloy wire as described in any one of the above, comprising the following steps:

[0037] (1) Sealing magnesium, a copper-phosphorus master alloy, and a copper-rare earth element master alloy in a copper tube to obtain a sealed copper tube;

[0038] (2) Melting copper to obtain a copper melt;

[0039] (3) Inserting the sealed copper tube into the copper melt. After magnesium, the copper-phosphorus master alloy, and the copper-rare earth element master alloy are melted, lifting the sealed copper tube and removing it to obtain an alloy melt;

[0040] (4) Casting the alloy melt into an ingot, and then successively performing hot extrusion, primary drawing, heat treatment, and secondary drawing on the ingot to obtain a copper-magnesium alloy wire.

[0041] In the present invention, first, magnesium, a copper-phosphorus master alloy, and a copper-rare earth element master alloy are sealed in a copper tube to obtain a sealed copper tube.

[0042] In some embodiments of the present invention, the mass content of phosphorus in the copper-phosphorus master alloy is 13-15%, for example, it can be 13%, 14%, 15%, etc., and the mass content of rare earth elements in the copper-rare earth element master alloy is 15-25%, for example, it can be 15%, 20%, 25%, etc. Since the surfaces of rare earth elements and phosphorus are easily oxidized, and slag may be introduced into the alloy melt after oxidation, rare earth elements and phosphorus are both selected to be added in the form of master alloys, which can effectively avoid introducing other impurities, ensure the accuracy and uniformity of the alloy composition, and improve the quality of the ingot.

[0043] It should be noted that the copper-phosphorus master alloy and the copper-rare earth element master alloy used in the present invention can both be obtained by market purchase. Therefore, the mass content of phosphorus in the copper-phosphorus master alloy and the mass content of rare earth elements in the copper-rare earth element master alloy are not specially limited and can be purchased and used according to actual situations.

[0044] In some embodiments of the present invention, sealing magnesium, a copper-phosphorus master alloy, and a copper-rare earth element master alloy in a copper tube can be achieved by the following method: placing magnesium, the copper-phosphorus master alloy, and the copper-rare earth element master alloy in the cavity of the copper tube, and then squeezing the edge of the copper tube until there is no gap, so as to effectively prevent the leakage of magnesium, the copper-phosphorus master alloy, and the copper-rare earth element master alloy, and ensure the accuracy of the addition amount of each component.

[0045] In the present invention, copper is melted to obtain a copper melt.

[0046] In some embodiments of the present invention, the smelting is carried out under a protective atmosphere, and the protective atmosphere can be, for example, argon, nitrogen, etc. The pressure of the smelting is 0.04 - 0.06 MPa, which can be, for example, 0.04 MPa, 0.05 MPa, 0.06 MPa, etc. Since the melting point of copper is 1083 °C, the smelting temperature of the present invention is greater than 1083 °C. Under vacuum conditions, the copper liquid is prone to boiling and sputtering. By inflating to increase the pressure in the furnace, the present invention can effectively reduce the boiling and sputtering of the copper liquid.

[0047] In some embodiments of the present invention, the smelting is carried out in a vacuum medium-frequency electromagnetic induction furnace. Before smelting, the vacuum medium-frequency electromagnetic induction furnace is evacuated to 30 - 50 Pa, and a protective atmosphere such as argon is filled into the cavity of the vacuum medium-frequency electromagnetic induction furnace for gas washing, and then evacuated to 10 -2 Pa, and then a protective atmosphere such as argon is filled into the cavity of the vacuum medium-frequency electromagnetic induction furnace. After the pressure in the cavity reaches 0.04 - 0.06 MPa, the inflation is stopped, and heating is started for smelting.

[0048] In some embodiments of the present invention, the purity of magnesium is ≥99.9%, and the purity of copper is ≥99.9%. Among them, the copper can be industrial electrolytic copper. By limiting the purity of magnesium and copper, it can ensure that the obtained copper-magnesium alloy wire has good mechanical strength and electrical conductivity.

[0049] In the present invention, after obtaining the copper melt, the sealed copper tube is inserted into the copper melt. After the magnesium, copper-phosphorus master alloy, and copper-rare earth element master alloy are melted, the sealed copper tube is lifted and removed to obtain an alloy melt.

[0050] In some embodiments of the present invention, during the melting process, the temperature of the copper melt is always maintained at 1150 - 1300 °C, which can be, for example, 1150 °C, 1200 °C, 1250 °C, 1300 °C, etc. By maintaining the temperature of the copper melt, the magnesium, copper-phosphorus master alloy, and copper-rare earth element master alloy in the sealed copper tube can be completely melted into the copper melt.

[0051] In some embodiments of the present invention, the insertion speed is 0.5 - 1 m / s, which can be, for example, 0.5 m / s, 0.6 m / s, 0.7 m / s, 0.8 m / s, 0.9 m / s, 1 m / s, etc. The melting speed of the sealed copper tube and the magnesium, copper-phosphorus master alloy, and copper-rare earth element master alloy inside it is very fast. If the insertion speed is too slow, the magnesium, copper-phosphorus master alloy, and copper-rare earth element master alloy will melt and volatilize above the liquid level of the copper melt, or react with the residual oxygen, etc., resulting in inaccurate addition amounts.

[0052] It should be noted that magnesium, copper-phosphorus master alloy, and copper-rare earth element master alloy are coated in a sealed copper tube and then inserted into the copper melt to enable the added elements to better dissolve in the copper body and avoid ablation and volatilization. Additionally, the melting points of magnesium, copper-phosphorus master alloy, and copper-rare earth element master alloy are lower than that of copper. After inserting the sealed copper tube into the copper melt, they can quickly melt. After the magnesium, copper-phosphorus master alloy, and copper-rare earth element master alloy melt, the remaining copper tube above the copper melt surface is lifted to facilitate the subsequent casting process.

[0053] In the present invention, after obtaining the alloy melt, the alloy melt is cast into an ingot, and then the ingot is successively subjected to hot extrusion, primary drawing, heat treatment, and secondary drawing to obtain copper-magnesium alloy wire.

[0054] In some embodiments of the present invention, the casting temperature is 1150 - 1300 °C, for example, it can be 1150 °C, 1200 °C, 1250 °C, 1300 °C, etc. Specifically, the alloy melt can be cast into a mold to obtain an ingot. The mold can be made of graphite, and the diameter of the mold can be 18 - 22 mm, for example, it can be 18 mm, 20 mm, 22 mm, etc. It should be noted that the casting temperature affects the quality of the ingot. If the casting temperature is too high, it will cause more and larger shrinkage cavities in the ingot. If the casting temperature is too low, it will cause a decrease in the strength of the ingot.

[0055] In some embodiments of the present invention, the hot extrusion temperature is 500 - 600 °C, for example, it can be 500 °C, 520 °C, 550 °C, 580 °C, 600 °C, etc. Specifically, after heating the ingot to 500 - 600 °C, the ingot is hot extruded into a round rod shape. The diameter of the round rod-shaped ingot can be 8 - 12 mm, for example, it can be 8 mm, 10 mm, 12 mm, etc. Through hot extrusion, the diameters of multiple ingots for drawing operations can be made uniform to ensure the uniform size of the final copper-magnesium alloy wire.

[0056] In some embodiments of the present invention, facing is also included before hot extrusion. The specific process of facing is not particularly limited and can refer to the prior art. Through facing, defects such as pores, shrinkage cavities, and dross on the surface of the ingot can be removed, improving the quality of the ingot.

[0057] In some embodiments of the present invention, the primary drawing is cold deformation drawing, and the drawing rate of the primary drawing is 2 - 4 m / min, for example, it can be 2 m / min, 3 m / min, 4 m / min, etc. Through the primary drawing, the diameter of the round rod-shaped ingot can be further reduced. For example, through the primary drawing, the round rod-shaped ingot is reduced to a diameter of 4 - 8 mm, for example, it can be 4 mm, 6 mm, 8 mm, etc.

[0058] In some embodiments of the present invention, the heat treatment is to hold at 200 - 260 °C for 2 h and then perform quenching treatment. Among them, the heat treatment temperature can be, for example, 200 °C, 220 °C, 240 °C, 260 °C, etc. The quenching treatment can use water as the cooling medium, and the ingot is put into water for cooling and quenching treatment. There are no special regulations for the process of quenching treatment, and it can refer to the prior art. Through heat treatment and quenching treatment, the strength, plasticity, etc. of the material can be further improved.

[0059] In some embodiments of the present invention, the secondary drawing is cold deformation drawing, and the drawing rate of the secondary drawing is 2 - 4 m / min, for example, it can be 2 m / min, 3 m / min, 4 m / min, etc. Through the secondary drawing, the diameter of the material after heat treatment can be further reduced. For example, through the secondary drawing, the ingot is reduced to a diameter of 0.1 - 0.15 mm, that is, a copper-magnesium alloy wire.

[0060] It should be noted that during the entire drawing operation, the diameter of the ingot gradually decreases until the final copper-magnesium alloy wire is obtained, which requires the use of dies with different diameters. For example, in a specific embodiment of the present invention, a round bar-shaped ingot with a diameter of 10 mm is obtained after hot extrusion. First, a single drawing process is performed on the round bar-shaped ingot with a diameter of 10 mm. The hole diameters of the multiple dies used in sequence during the single drawing process are as follows: 10 mm → 9.8 mm → 9.5 mm → 9.2 mm → 9.0 mm → 8.8 mm → 8.2 mm → 8 mm → 7.8 mm → 7.5 mm → 7.3 mm → 7.0 mm → 6.7 mm → 6.5 mm → 6.3 mm → 6 mm. After the round bar-shaped ingot is drawn to 6 mm, heat treatment and quenching operations are performed; then a double drawing process is carried out. The hole diameters of the multiple dies used in sequence during the double drawing process are as follows: 5.8 mm → 5.6 mm → 5.4 mm → 5.2 mm → 5.0 mm → 4.8 mm → 4.6 mm → 4.4 mm → 4.2 mm → 4.0 mm → 3.8 mm → 3.6 mm → 3.4 mm → 3.2 mm → 3.0 mm → 2.8 mm → 2.6 mm → 2.4 mm → 2.2 mm → 2.0 mm → 1.8 mm → 1.6 mm → 1.4 mm → 1.2 mm → 1.0 mm → 0.9 mm → 0.82 mm → 0.75 mm → 0.7 mm → 0.67 mm → 0.62 mm → 0.6 mm → 0.55 mm → 0.5 mm → 0.46 mm → 0.44 mm → 0.4 mm → 0.38 mm → 0.35 mm → 0.33 mm → 0.3 mm → 0.28 mm → 0.26 mm → 0.24 mm → 0.22 mm → 0.2 mm → 0.18 mm → 0.16 mm → 0.15 mm. Since the drawing process uses a large number of dies with different hole diameters for continuous drawing, the size uniformity of the prepared copper-magnesium alloy wire is good and its performance is stable. However, the selection of the die hole diameter is not limited to this, and the use of dies with different hole diameters can be increased or decreased according to the size and performance requirements of the copper-magnesium alloy wire.

[0061] Through the above processes of hot extrusion, single drawing, heat treatment and quenching treatment, and double drawing of the ingot of the present invention, the strength of the alloy wire can be effectively improved, and at the same time, the alloy wire can maintain a high conductivity.

[0062] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with specific embodiments. The embodiments of this application are only for illustration. All other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present invention.

[0063] Example 1

[0064] This embodiment provides a copper-magnesium alloy wire. By mass percentage, it consists of the following components: magnesium 0.12%, phosphorus 0.007%, rare earth elements 0.002%, and the balance is copper and inevitable impurities.

[0065] The preparation method of the copper-magnesium alloy wire is as follows:

[0066] (1) Take Cu (purity 99.9%), Mg (purity 99.9%), Cu-14%P master alloy, and Cu-20%Ce master alloy as raw materials. Place Mg, Cu-14%P master alloy, and Cu-20%Ce master alloy in the cavity of a copper tube, and then squeeze the edge of the copper tube until there is no gap to obtain a sealed copper tube.

[0067] (2) Put Cu into a graphite crucible and melt it in a medium-frequency induction furnace under argon protection. Before melting, evacuate the medium-frequency induction furnace to 40 Pa, fill the medium-frequency induction furnace with argon for purging, then evacuate it to 10 -2 Pa, and then fill the cavity of the medium-frequency induction furnace with argon until the pressure in the cavity is 0.05 MPa and then stop filling. Turn on the heating and carry out melting. After Cu is completely melted, obtain a copper melt.

[0068] (3) Keep the temperature of the copper melt at 1200 °C, insert the sealed copper tube into the copper melt at a speed of 0.5 m / s. After the sealed copper tube and the magnesium, Cu-14%P master alloy, and Cu-20%Ce master alloy it encloses are completely melted, lift the copper tube above the copper melt surface and remove it to obtain an alloy melt.

[0069] (4) At a temperature of 1200 °C, pour the alloy melt into a graphite mold with a diameter of 20 mm to obtain an ingot. Perform a facing treatment on the ingot to mill away defects such as pores, shrinkage cavities, and dross on the surface of the ingot.

[0070] (5) Heat the ingot after facing treatment to 550 °C and hot extrude it to 10 mm to obtain a round-bar-shaped ingot.

[0071] (6) Perform cold deformation drawing on the round-bar-shaped ingot to a diameter of 6 mm, and the drawing rate is 4 m / min. This drawing process is completed by means of molds with different hole diameters. The hole diameters of the molds used are in sequence: 10 mm → 9.8 mm → 9.5 mm → 9.2 mm → 9.0 mm → 8.8 mm → 8.2 mm → 8 mm → 7.8 mm → 7.5 mm → 7.3 mm → 7.0 mm → 6.7 mm → 6.5 mm → 6.3 mm → 6 mm.

[0072] (7) Place a round bar ingot with a diameter of 6 mm into a heat treatment furnace, hold it at 240 °C for 2 h, then take it out of the heat treatment furnace and quickly put it into water for quenching treatment;

[0073] (8) Cold-deform and draw the round bar ingot that has undergone heat treatment and quenching treatment to a diameter of 0.15 mm at a drawing speed of 4 m / min to obtain a copper-magnesium alloy wire; this drawing process is completed by means of dies with different hole diameters, and the hole diameters of the dies used are in sequence: 5.8 mm → 5.6 mm → 5.4 mm → 5.2 mm → 5.0 mm → 4.8 mm → 4.6 mm → 4.4 mm → 4.2 mm → 4.0 mm → 3.8 mm → 3.6 mm → 3.4 mm → 3.2 mm → 3.0 mm → 2.8 mm → 2.6 mm → 2.4 mm → 2.2 mm → 2.0 mm → 1.8 mm → 1.6 mm → 1.4 mm → 1.2 mm → 1.0 mm → 0.9 mm → 0.82 mm → 0.75 mm → 0.7 mm → 0.67 mm → 0.62 mm → 0.6 mm → 0.55 mm → 0.5 mm → 0.46 mm → 0.44 mm → 0.4 mm → 0.38 mm → 0.35 mm → 0.33 mm → 0.3 mm → 0.28 mm → 0.26 mm → 0.24 mm → 0.22 mm → 0.2 mm → 0.18 mm → 0.16 mm → 0.15 mm.

[0074] Example 2-4

[0075] Example 2-4 is basically the same as Example 1, the only difference being that the component composition of the copper-magnesium alloy wire is different.

[0076] Comparative Example 1

[0077] This comparative example is basically the same as Example 1, the only difference being that the component composition of the copper-magnesium alloy wire is different.

[0078] Comparative Example 2

[0079] This comparative example is basically the same as Example 1, the only difference being that the component composition of the copper-magnesium alloy wire is different, and the drawing rates in steps (6) and (8) are independently 10 m / min.

[0080] For the component compositions of the copper-magnesium alloy wires in Examples 2-4 and Comparative Example 1, see Table 1.

[0081] Table 1

[0082]

[0083]

[0084] The tensile strength and conductivity properties of the copper-magnesium alloy wires prepared in Examples 1-4 and Comparative Examples 1-2 were tested, and the results are shown in Table 2. Among them, the test method for tensile strength refers to GB / T 4909.3-2009 Test Methods for Bare Wires - Part 3: Tensile Test; the test method for conductivity refers to GB / T 3048.2-2007 Test Methods for Electrical Properties of Electric Wires and Cables - Part 2: Resistivity Test for Metallic Materials; the parameters for hardness testing are as follows: test load 1.961 N (200 gf), holding time 15 s.

[0085] Table 2

[0086] Tensile strength (MPa) Electrical conductivity (%IACS) Hardness (HV) Example 1 813 80.2 225 Example 2 808 81.4 218 Example 3 793 80.7 214 Example 4 836 74.3 236 Comparative Example 1 774 84.7 201 Comparative Example 2 758 85.1 194

[0087] It can be concluded from Table 2 that the copper-magnesium alloy wires of the present invention can effectively improve the tensile strength while maintaining a relatively high conductivity. Among them, in Example 3, due to the relatively high addition amount of phosphorus, precipitation phases are formed, which leads to a decrease in the tensile strength of the copper-magnesium alloy wire. In Example 4, due to the relatively high addition amount of magnesium, the conductivity of the copper-magnesium alloy wire decreases, but at the same time, the tensile strength of the copper-magnesium alloy wire increases.

[0088] In addition, it can be seen from Comparative Examples 1-2 that if the drawing speed is increased, the conductivity of the copper-magnesium alloy wire slightly increases, but its strength and hardness will significantly decrease. Therefore, the present invention preferably limits the drawing rate to 2-4 m / min.

[0089] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A copper-magnesium alloy wire, characterized in that: The copper-magnesium alloy wire consists of copper, magnesium, phosphorus, rare earth elements and inevitable impurities. In terms of mass percentage, the magnesium content is 0.1-0.15%, and the phosphorus content is 0.007-0.02%.

2. The copper-magnesium alloy wire according to claim 1, characterized in that: The content of the rare earth element is 0.002-0.03%.

3. The copper-magnesium alloy wire according to claim 1 or 2, characterized in that: The rare earth element includes one or more of cerium, lanthanum, praseodymium and neodymium.

4. The copper-magnesium alloy wire according to claim 3, characterized in that: The rare earth element is cerium.

5. The copper-magnesium alloy wire according to claim 1, characterized in that: The content of magnesium is 0.12-0.15%.

6. The copper-magnesium alloy wire according to claim 1, characterized in that: The phosphorus content is 0.007-0.01%.

7. A method for preparing the copper-magnesium alloy wire according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) sealing magnesium, copper-phosphorus master alloy, and copper-rare earth element master alloy in a copper tube to obtain a sealed copper tube; (2) smelting copper to obtain a copper melt; (3) inserting the sealed copper tube into the copper melt, and after the magnesium, copper-phosphorus master alloy, and copper-rare earth element master alloy are melted, lifting and removing the sealed copper tube to obtain an alloy melt; (4) Casting the alloy melt into an ingot, and then sequentially subjecting the ingot to hot extrusion, primary drawing, heat treatment and secondary drawing to obtain a copper-magnesium alloy wire.

8. The method for preparing the copper-magnesium alloy wire according to claim 7, characterized in that: The mass content of phosphorus in the copper-phosphorus master alloy is 13-15%; The mass content of the rare earth element in the copper-rare earth element master alloy is 15-25%.

9. The method for preparing the copper-magnesium alloy wire according to claim 7, characterized in that: The smelting is carried out under a protective atmosphere; The smelting pressure is 0.04-0.06MPa.

10. The method for preparing the copper-magnesium alloy wire according to claim 7, characterized in that: In step (3), the temperature of the copper melt is maintained at 1150-1300°C.

11. The method for preparing the copper-magnesium alloy wire according to claim 7, characterized in that: The insertion speed is 0.5-1 m / s.

12. The method for preparing the copper-magnesium alloy wire according to claim 7, characterized in that: The casting temperature is 1150-1300°C.

13. The method for preparing the copper-magnesium alloy wire according to claim 7, characterized in that: The temperature of the hot extrusion is 500-600°C; The heat treatment is to keep the temperature at 200-260°C for 2h and then perform quenching treatment; The primary drawing and the secondary drawing are both cold deformation drawing, and the drawing rates of the primary drawing and the secondary drawing are independently 2-4 m / min.

14. The method for preparing a copper-magnesium alloy wire according to any one of claims 7 to 13, characterized in that: The ingot is cylindrical, and the diameter of the ingot is 18-22 mm. The diameter of the ingot after the hot extrusion treatment is 8-12 mm, the diameter of the ingot after the primary drawing treatment is 4-8 mm, and the diameter of the copper-magnesium alloy wire after the secondary drawing treatment is 0.1-0.15 mm.

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