Manufacturing method of copper-magnesium alloy contact wire suitable for 450km / h high-speed rail

Abstract

The invention discloses a manufacturing method of a copper-magnesium alloy contact wire suitable for a 450km / h high-speed rail, and belongs to the technical field of alloys. The method comprises the following steps: after completely melting a cathode copper plate with a clean surface, adding a magnesium ingot or a copper-magnesium intermediate alloy; after the copper-magnesium alloy is fully molten, adding a copper-calcium intermediate alloy, after the copper-calcium intermediate alloy is molten, cooling the molten alloy, and treating to form a copper-magnesium alloy cast rod; extruding the copper-magnesium alloy casting rod to obtain an extruded rod; the extruded extrusion rod is rolled into a rolled rod; and drawing the rolling rod for multiple times in sequence to form the copper-magnesium alloy contact wire with the cross section area of 120150. According to the alloy composition proportion and the processing technology provided by the invention, the contact line meets the strict requirements of a 450km / h high-speed railway, has high tensile strength, high conductivity and excellent vibration resistance and fatigue resistance, meets related standards, and is suitable for operation of an ultra-high-speed railway.

Description

Technical Field

[0001] This invention belongs to the field of alloy technology, specifically relating to a method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways. Background Technology

[0002] With continuous breakthroughs in high-speed rail technology, such as the Chengdu-Chongqing Central Line High-Speed ​​Railway currently under construction, its maximum design speed has been significantly increased to 450 km / h. The development of this ultra-high-speed railway poses unprecedented performance challenges to the contact wire, the core component of the overhead contact system.

[0003] As a crucial conductor in the electrified railway overhead contact system, directly sliding in contact with the train's pantograph and transmitting electrical energy, the performance of the contact wire directly affects the power supply stability and operational safety of the train. The copper-magnesium alloy (CTMH) contact wire widely used in the current TB / T2809-2017 standard has a tensile strength of 530 MPa. However, this strength is insufficient to meet the 560 MPa strength requirement of a 36 kN tension for a 450 km / h high-speed train. Simultaneously, with the continuous increase in train speed, energy consumption is drastically increasing. This necessitates that the contact wire, while ensuring ultra-high strength, also possess excellent conductivity (≥65% IACS) to reduce power transmission losses and improve energy efficiency. Furthermore, under ultra-high-speed friction conditions, the contact wire material must also possess excellent fatigue resistance to meet the long-term stable operation requirements in complex environments. Therefore, further improving the tensile strength and fatigue resistance of the contact wire while maintaining excellent conductivity has become a key direction in the current research and development of high-speed railway contact wires.

[0004] To address this need, the industry has conducted a series of related studies and achieved certain results. For example, the patent CN117139404A, "A Method for Preparing High-Strength, High-Conductivity Copper-Magnesium Alloy Contact Wire Suitable for 400km / h High-Speed ​​Railways," uses specific copper-magnesium alloy composition design and preparation processes such as continuous casting, continuous extrusion, and multi-pass drawing to produce contact wires suitable for high-speed railways at certain speeds. However, in actual production, when the ratio of the outlet diameter to the inlet diameter is too large in the continuous extrusion process, it leads to excessive cumulative deformation in subsequent multi-pass drawing, causing localized stress concentration within the material. This results in surface quality problems such as cracks and peeling in the groove area, and poor fatigue resistance, making it difficult to meet the durability requirements of 450km / h high-speed railway contact wires. Furthermore, it is difficult to achieve continuous production of large lengths during mass production. The patent CN110666173A, "Graphene Copper-Magnesium Alloy Contact Wire and its Preparation Method," produces contact wires with relatively excellent tensile strength and conductivity. However, the overall alloy composition is outside the range specified in relevant standards, potentially leading to product stability risks. Furthermore, the hot isostatic pressing process requires sophisticated equipment, and the high cost of graphene copper-magnesium alloy powder limits its practical application. The patent CN118417361A, "A Process Control Method for High-Strength Copper-Magnesium Alloy Contact Wire," while mitigating stress concentration and reducing surface defects by controlling the distribution of drawing deformation, does not significantly improve tensile strength and cannot meet the stringent requirements of 450km / h high-speed railways for high strength and fatigue resistance in contact wires. Therefore, developing a contact wire preparation technology that meets the requirements of 450km / h high-speed railways is urgently needed. Summary of the Invention

[0005] Existing copper-magnesium alloy contact wire manufacturing methods suffer from several drawbacks, including stress concentration within the material after continuous extrusion followed by drawing, poor surface quality, and insufficient fatigue resistance, making them unsuitable for the durability requirements of 450km / h high-speed railways. This invention provides a method for manufacturing copper-magnesium alloy contact wires suitable for 450km / h high-speed railways. The provided alloy composition ratio and processing technology ensure that the contact wire meets the stringent requirements of 450km / h high-speed railways, possessing high tensile strength, high conductivity, excellent vibration and fatigue resistance, and conforming to relevant standards, making it suitable for ultra-high-speed railway operation.

[0006] To achieve the above objectives, the present invention provides the following technical solution.

[0007] This invention provides a method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways, comprising the following steps: S100: After the clean cathode copper plate is completely melted, magnesium ingots or copper-magnesium master alloy are added; and after it is fully melted, copper-calcium master alloy is added. After the copper-calcium master alloy melts, the molten alloy is cooled and processed to form a copper-magnesium alloy casting rod. S200: Extruded rods are obtained by extruding copper-magnesium alloy cast rods; S300: Roll the extruded extrusion bar into a rolled bar; S400: The rolled bar is drawn multiple times to form a cross-sectional area of ​​120. 150 Copper-magnesium alloy contact wire.

[0008] As a further improvement of the present invention, the cleaned cathode copper plate is completely melted, magnesium ingots are added and allowed to fully melt, including: During smelting, the addition ratio of magnesium ingots is 0.60~0.70 wt.%.

[0009] As a further improvement of the present invention, the clean cathode copper plate is completely melted, a copper-magnesium intermediate alloy is added and allowed to fully melt, including: When adding 50% copper-magnesium master alloy, the addition ratio is 1.2~1.4 wt.%.

[0010] As a further improvement of the present invention, the addition of copper-calcium master alloy includes: the addition ratio of Ca30% copper-calcium master alloy is 0.15~0.40 wt.

[0011] As a further improvement of the present invention, the Mg content in the copper-magnesium alloy cast rod is 0.50-0.65 wt.%, and the Ca content is 0.03-0.1 wt.%.

[0012] As a further improvement of the present invention, the diameter of the copper-magnesium alloy cast rod is 25-30mm.

[0013] As a further improvement of the present invention, the preheating temperature of the extruder cavity is 450~500℃, the heat preservation time is 60~90min, the main current of the extruder is 500~1000A, and the spindle speed is 1.2~2.2rpm.

[0014] As a further improvement of the present invention, the rolling is cold rolling, and the rolling speed is 100~160m / min.

[0015] As a further improvement of the present invention, the diameter of the rolling bar is 20~24mm.

[0016] As a further improvement of the present invention, the diameter of the extrusion rod is 23~30mm.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention precisely controls the alloy composition ratio, sequentially adding cathode copper plates, magnesium ingots or copper-magnesium master alloys, and copper-calcium master alloys during the smelting process. This ensures uniform distribution of elements within the alloy, with calcium forming a second-phase strengthening layer and magnesium fully dissolved in the copper matrix, creating a microstructure with grain boundary pinning effect. This alloy composition design gives the contact wire not only high tensile strength, capable of withstanding the enormous working tension during high-speed train operation and effectively preventing safety hazards such as contact wire breakage, ensuring the safety and stability of high-speed rail operation, but also high conductivity, significantly reducing energy loss during power transmission and improving energy efficiency. In the preparation process, a copper-magnesium alloy casting rod is first formed through cooling in a crystallizer and the action of a traction device. This step ensures the initial quality and performance stability of the casting rod. Subsequently, the casting rod is extruded to obtain an extruded rod, which is then rolled into a rolled rod using a continuous rolling mill. This step-by-step processing method helps to gradually optimize the internal structure of the material and reduce internal defects. The process of repeatedly drawing the rolled wire through multiple stages, compared to the traditional single-stage or fewer-stage drawing method, can more evenly distribute the internal stress of the material, avoiding stress concentration. The multiple drawing processes make the contact wire surface smoother and flatter, significantly improving surface quality and extending the contact wire's service life. Simultaneously, it greatly enhances the contact wire's vibration and fatigue resistance, enabling it to maintain good performance even under frequent vibration and reciprocating stress at high speeds of 450 km / h, resisting fatigue cracks and fractures, thus fully meeting the stringent durability requirements of ultra-high-speed railways. Attached Figure Description

[0018] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. In the drawings: Figure 1 This is a schematic flowchart of a method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways according to the present invention. Figure 2 This is a schematic diagram illustrating the specific process of a method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways according to the present invention. Figure 3 This is a schematic diagram of the cross-sectional shape of a copper-magnesium alloy contact wire; Figure 4 The images show the identification groove for copper-magnesium alloys and an enlarged view of the identification groove; where (a) is an enlarged schematic diagram of the identification groove for copper-magnesium alloys; and (b) is an enlarged schematic diagram of the identification groove. Wherein, A is the cross-sectional diameter; B is the cross-sectional width; C is the head width; D is the groove bottom spacing; E is the groove tip spacing; K is the head height; R is the fillet radius; H is the upper bevel angle; and G is the lower bevel angle. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] Existing copper-magnesium alloy contact wire manufacturing methods suffer from several drawbacks, including stress concentration after continuous extrusion followed by drawing, poor surface quality, and insufficient fatigue resistance, making them unsuitable for the durability requirements of 450km / h high-speed trains. This invention provides a method for manufacturing copper-magnesium alloy contact wires suitable for 450km / h high-speed trains. Figure 1 As shown, it includes: S100: After the clean cathode copper plate is completely melted, magnesium ingots or copper-magnesium master alloy are added; and after it is fully melted, copper-calcium master alloy is added. After the copper-calcium master alloy melts, the molten alloy is cooled and processed to form a copper-magnesium alloy casting rod. S200: Extruded rods are obtained by extruding copper-magnesium alloy cast rods; S300: Roll the extruded extrusion bar into a rolled bar; S400: The rolled bar is drawn multiple times to form a cross-sectional area of... Copper-magnesium alloy contact wire.

[0022] The alloy composition ratio and processing technology provided by this invention enable the contact wire to meet the stringent requirements of 450km / h high-speed railways, possessing high tensile strength, high conductivity, excellent vibration resistance and fatigue resistance, and conforming to relevant standards, making it suitable for ultra-high-speed railway operation.

[0023] The present invention will be further explained and described below with reference to the accompanying drawings.

[0024] The copper-magnesium alloy contact wire of this application uses copper and the strengthening alloying element Mg as raw materials. It is processed by continuous casting → continuous extrusion → rolling → multi-pass drawing, and finally formed into a regular circle with suspension grooves and alloy type identification grooves.

[0025] like Figure 2As shown, the present invention discloses a method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways, which specifically includes the following steps.

[0026] S1: Upward Continuous Casting: Cleaned cathode copper plates (copper content ≥99.99wt.%) are baked and dehydrated before being fed into the melting furnace. After the copper plates are completely melted, precisely measured magnesium ingots (or Mg 50% copper-magnesium master alloy) are added and allowed to melt fully. Subsequently, precisely measured Ca 30% copper-calcium master alloy is added to the melting furnace. The surface of the molten alloy is covered with graphite flakes to isolate oxygen. The molten alloy is then cooled through a crystallizer and formed into a casting rod under the action of a traction device. Specific key control parameters are: copper melt temperature 1190~1210℃, crystallizer depth 180~250mm below the copper melt, graphite flake thickness covering the molten alloy surface 80~120mm, upward traction speed 300~350mm / min; magnesium ingot addition ratio 0.60~0.70. wt.% (or 1.2~1.4wt.% when adding Mg 50% copper-magnesium master alloy), and 0.15~0.40wt.% when adding Ca 30% copper-calcium master alloy; the Mg content of the copper-magnesium alloy casting rod is 0.50~0.65wt.%, and the Ca content is 0.03~0.1wt.%; the specifications of the upward drawn copper wire blank are Φ25~Φ30mm.

[0027] S2: Continuous Extrusion: After preheating the die cavity of the extruder, the die is assembled. Then, the Φ25~Φ30mm upward-drawn copper-magnesium alloy cast rod is fed into the continuous extruder after surface treatment such as grinding. The extrusion process yields an extruded rod with a diameter of Φ23~Φ30mm. Specific control parameters are: die cavity preheating temperature 450~500℃, holding time 60~90min, main machine current 500~1000A, and spindle speed 1.2~2.2rpm during extrusion operation.

[0028] S3: Rolling (cold rolling): The extruded copper rod is rolled into a Φ20mm~Φ24mm rod by a continuous rolling mill at a rolling speed of 100~160m / min.

[0029] S4: Multi-die drawing: The rolling bar, after continuous rolling, is passed successively through a series of dies with gradually decreasing dimensions, such as... Figure 3 and Figure 4 As shown, it is ultimately shaped into a form with a cross-sectional area of ​​120. 150 Alternatively, copper-magnesium alloy contact wires of other sizes can be used. Specific control parameters are: flaw detection gain of 40~60dB and drawing speed of 15~22m / min.

[0030] The present invention will be further explained and illustrated below with reference to specific embodiments.

[0031] Example 1 The specific operating steps are as follows: S1: Upward Continuous Casting: Cleaned cathode copper plates (copper content ≥ 99.99 wt.%) are baked and dehydrated before being fed into the melting furnace. After the copper plates are completely melted, precisely measured magnesium ingots are added and allowed to melt fully. Subsequently, precisely measured 30% copper-calcium master alloy (Ca30%) is added to the melting furnace. The surface of the molten alloy is covered with graphite flakes to isolate oxygen. The molten alloy is then cooled through a crystallizer and formed into a casting rod under the action of a traction device. Specific control parameters are: copper melt temperature of 1195℃, traction speed of 320mm / min; Mg ingot addition ratio of 0.67 wt.%, Ca30% copper-calcium master alloy addition ratio of 0.30 wt.%; and the specification of the upward casting rod is Φ26mm.

[0032] S2: Continuous Extrusion: After preheating the die cavity of the extruder, the Φ26 upward-drawn copper-magnesium alloy cast rod is assembled, and then fed into the continuous extruder after surface treatment such as grinding. The extrusion produces an extruded rod with a diameter of Φ28mm. The specific control parameters are: die cavity preheating temperature 460℃, holding time 60min, main machine current 700A, and main shaft speed 1.4rpm during extruder operation.

[0033] S3: Rolling: The extruded copper rod is rolled into a Φ22mm rod using a continuous rolling mill at a rolling speed of 120m / min.

[0034] S4: Multi-die drawing: The continuously rolled bar is passed through a series of dies with gradually decreasing dimensions until it is finally shaped into a cross-sectional area of ​​150mm². 2 The copper-magnesium alloy contact wire was used. Specific control parameters were: flaw detection gain of 45dB and drawing speed of 16m / min.

[0035] Example 2 According to Example 1, a cross-sectional area of ​​150 was prepared. The difference between the copper-magnesium alloy contact wire and the extrusion rod is that the extrusion rod is not rolled, but directly drawn through multiple dies, and finally formed into a cross-sectional area of ​​150. Copper-magnesium alloy contact wire.

[0036] Example 3 The specific operating steps are as follows: According to Example 1, a cross-sectional area of ​​150 was prepared. The copper-magnesium alloy contact wire differs in that no Ca30% copper-calcium master alloy is added in step 1. It is then extruded, rolled, and drawn using multiple dies to finally form a wire with a cross-sectional area of ​​150 mm. Copper-magnesium alloy contact wire.

[0037] Comparative Example 1 According to Example 1, a cross-sectional area of ​​150 was prepared. The copper-magnesium alloy contact wire differs in that it does not contain a 30% copper-calcium master alloy (Ca) in step 1. It is then extruded and drawn using multiple dies to ultimately form a wire with a cross-sectional area of ​​150 mm. Copper-magnesium alloy contact wire.

[0038] Electromechanical performance tests were conducted on Examples 1-3 and Comparative Example 1 according to the inspection content and test requirements of standard TB / T 2809-2017. For the strength requirement of 36kN tension on the contact wire of a 450km / h high-speed railway, the standard values ​​of tensile strength (≥560MPa) and breaking force (≥82.87kN) were calculated. Other performance standard values ​​were determined according to the technical requirements for CTMH150 in TB / T 2809-2017. The test results are detailed in Table 1.

[0039] Table 1 Test results of linear electromechanical properties of copper-magnesium alloy contact

[0040] As shown in Table 1, the tensile strength (556.9 MPa), number of repeated bending cycles until cracking (3 times), and surface quality of Comparative Example 1 did not meet the standard requirements. By comparing Example 2 and Comparative Example 1, it can be concluded that the introduction of trace amounts of Ca effectively improved the tensile strength and conductivity of the contact wire. By comparing Example 3 and Comparative Example 1, it can be concluded that adding a rolling process effectively improved the tensile strength and surface quality of the contact wire. By comparing Example 1 and Comparative Example 1, it can be concluded that the introduction of trace amounts of Ca and the addition of a rolling process, while improving tensile strength, conductivity, and surface quality, also improved the vibration resistance and fatigue resistance of the contact wire.

[0041] This invention addresses the stringent requirements of high strength, high conductivity, and fatigue resistance for contact wires in 450km / h high-speed railways. It provides an innovative alloy composition ratio and processing technology to achieve a tensile strength exceeding 560MPa, meeting the working tension requirement of 36kN; and a conductivity ≥65% IACS; simultaneously exhibiting excellent vibration and fatigue resistance, meaning that under specified test tension, after 2.6×10⁻⁶... 6 Secondary vibration test and 6.5×10 5 After the fatigue test, the sample did not break; the chemical composition and other performance parameters all meet the requirements of CTMH in TB / T2809-2017, providing a high-strength fatigue-resistant copper-magnesium alloy contact wire for 450km / h high-speed railways.

[0042] During production, based on the traditional continuous casting → continuous extrusion → multi-die drawing process, a trace amount of Ca is introduced to form a synergistic strengthening mechanism. The total deformation is increased by expanding the exit diameter of the continuous extrusion, and a rolling process is added after extrusion. The multi-directional stress of rolling not only promotes the formation of dispersed strengthening phases of Ca, enhancing grain refinement and dislocation pinning effects, but also improves the uniformity of the internal microstructure and surface quality, effectively eliminating the cumulative strain concentration phenomenon caused by direct drawing. Finally, the product is processed through multi-die drawing to achieve a cross-sectional area of ​​120 mm. 150 Or copper-magnesium alloy contact wires of other sizes.

[0043] In summary, this invention optimizes the composition ratio of copper-magnesium alloy, innovatively introduces Ca element, and further improves the tensile strength and conductivity of the contact wire through second-phase strengthening and matrix purification. Furthermore, by increasing the extrusion deformation, a rolling process is added, solving the surface quality problem caused by stress concentration resulting from direct drawing. Simultaneously, it improves the vibration resistance and fatigue resistance of the contact wire, enabling mass production. The specific beneficial effects are reflected in the following four aspects: (1) High strength guarantee: Ultra-high strength meets the working tension requirements of 450km / h: By optimizing the alloy composition, a trace amount of Ca element is introduced to form a second phase for strengthening, which significantly improves the strength in synergy with Mg. At the same time, by optimizing the continuous extrusion outlet diameter to Φ25~Φ30mm, the rolling process obtains sufficient deformation reserve; through rolling-induced lattice distortion strengthening, combined with step drawing strain control, the final contact wire tensile strength can stably reach ≥560 MPa, meeting the 36 kN working tension requirement of the contact wire for 450 km / h high-speed rail.

[0044] (2) High conductivity guarantee: The addition of Ca can effectively combine with impurity elements to form high-melting-point compounds, which are removed through the slag removal process, significantly purifying the copper matrix, reducing matrix lattice distortion, and indirectly reducing electron scattering. At the same time, the subsequent rolling process further reduces the dislocation density of the material and reduces electron scattering paths. The synergistic effect of the two ensures that the conductivity of the finished contact wire is improved to ≥65% IACS.

[0045] (3) Enhanced vibration and fatigue resistance: Ca, through the formation of second-phase particles, hinders dislocation movement and pins grain boundaries. Combined with the homogenization effect brought about by the rolling process, this significantly improves the material's resistance to cyclic loading. The product's vibration and fatigue resistance are significantly improved, and it can withstand 2.6 × 10⁻⁶ cycles under specified test tension. 6 Secondary vibration test and 6.5×10 5 After the fatigue test, the sample did not break, which is higher than the standard requirements of TB / T2809-2017.

[0046] (4) Ensure product surface quality: Rolling, as an intermediate process between extrusion and drawing, completely solves the quality defects such as cracks and peeling caused by stress concentration in the groove area due to direct drawing of large-diameter extrusion rods, effectively ensuring the surface quality of the product and enabling mass production.

[0047] Many embodiments and applications beyond the examples provided will be apparent to those skilled in the art upon reading the foregoing description. Therefore, the scope of this teaching should not be determined by reference to the foregoing description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

[0048] The above content provides a further detailed description of the present invention. It should not be construed that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection of the present invention as defined by the submitted claims.

Claims

1. A method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways, characterized in that, Includes the following steps: S100: After the cleaned cathode copper plate is completely melted, magnesium ingots or copper-magnesium intermediate alloy are added. After it is fully melted, a copper-calcium master alloy is added. After the copper-calcium master alloy melts, the molten alloy is cooled and processed to form a copper-magnesium alloy casting rod. S200: Extruded rods are obtained by extruding copper-magnesium alloy cast rods; S300: Roll the extruded extrusion bar into a rolled bar; S400: The rolled bar is drawn multiple times to form a cross-sectional area of ​​120. 150 Copper-magnesium alloy contact wire.

2. The method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways according to claim 1, characterized in that: The cleaned cathode copper plate is completely melted, magnesium ingots are added and allowed to melt fully, including: During smelting, the addition ratio of magnesium ingots is 0.60~0.70 wt.%.

3. The method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways according to claim 1, characterized in that, The cleaned cathode copper plate is completely melted, and a copper-magnesium master alloy is added and allowed to melt fully, including: When adding 50% copper-magnesium master alloy, the addition ratio is 1.2~1.4 wt.%.

4. The method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways according to claim 1, characterized in that, The addition of copper-calcium master alloy includes: the addition ratio of Ca30% copper-calcium master alloy is 0.15~0.40 wt.%.

5. The method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways according to claim 1, characterized in that, The Mg content in the copper-magnesium alloy cast rod is 0.50–0.65 wt.%, and the Ca content is 0.03–0.1 wt.%.

6. The method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways according to claim 1, characterized in that, The diameter of the copper-magnesium alloy cast rod is 25-30mm.

7. The method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways according to claim 1, characterized in that, The extruder has a preheating temperature of 450~500℃ and a holding time of 60~90min. When the extruder is working, the main current is 500~1000A and the spindle speed is 1.2~2.2rpm.

8. The method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways according to claim 1, characterized in that, The rolling process is cold rolling, and the rolling speed is 100~160m / min.

9. The method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways according to claim 1, characterized in that, The diameter of the rolling bar is 20~24mm.

10. A method for manufacturing a copper-magnesium alloy contact wire suitable for 450km / h high-speed railways according to claim 1, characterized in that, The diameter of the extrusion rod is 23~30mm.

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