Cu-Cr-X alloy contact wire and preparation method thereof

Abstract

According to the Cu-Cr-X alloy contact wire, Zr element replacement is achieved, working procedures and use of expensive alloy elements are reduced, low-cost manufacturing of the alloy contact wire is achieved, and the consistency of the product quality of the contact wire is ensured. The components forming the alloy contact wire body comprise Cu, Cr, X and inevitable impurities, the content of Cr ranges from 0.3 wt% to 0.6 wt%, X is one or a mixture of Ti and Si, the content of the inevitable impurities is smaller than 0.3 wt%, and the balance is copper.

Description

Technical Field

[0001] This invention relates to the technical field of railway contact wires, specifically a Cu-Cr-X alloy contact wire, and also provides a method for preparing the alloy contact wire. Background Technology

[0002] The contact wire is a key component of the overhead contact system in high-speed railways. During operation, it must withstand high tension, strong vibration, and impact, as well as carry large currents. This requires the contact wire to possess high strength, low linear density, high conductivity, and good wear resistance and corrosion resistance. Currently, the materials used for contact wires in high-speed electrified railways with speeds above 300 km / h are mainly Cu-Sn alloy, Cu-Mg alloy, and Cu-Cr-Zr alloy. Cu-Sn alloy contact wire has a tensile strength of 500 MPa and a conductivity of 68% IACS; Cu-Mg alloy contact wire has a tensile strength of 530 MPa and a conductivity of 65% IACS; and Cu-Cr-Zr alloy contact wire has a tensile strength of 560 MPa and a conductivity of 75% IACS (TB / T2809-2017 Copper and Copper Alloy Contact Wires for Electrified Railways). Due to the long manufacturing process of Cu-Cr-Zr alloy contact wires, the alloy element Zr is easily burned off, resulting in a low yield and high cost, and its large-scale application is not yet possible.

[0003] Therefore, researchers have made numerous improvements to the copper alloy contact wire for high-speed railways and its preparation methods.

[0004] Chinese patent document CN103966475A, entitled "A Copper-Chromium-Titanium Alloy Contact Wire and Its Preparation Method," provides a contact wire with an alloy composition of Cu-(0.15~0.35)%Cr-(0.10~0.23)%Ti-(0~0.05)%Mg-(0~0.02)%Si, and a total impurity content of no more than 0.1%. The preparation method is as follows: gas melting-continuous casting-solution quenching-continuous extrusion-aging treatment-rolling-drawing.

[0005] Chinese patent document CN116752060A, "A Production Process for Copper-Chromium-Zirconium Alloy Contact Wire," provides a contact wire with an alloy composition of Cu-(0.2~1.0)%Cr-(0.02~0.2)%Zr, and the sum of other elements is less than or equal to 0.1%. The preparation method is as follows: continuous casting → first cold working → solution treatment → cleaning billet → continuous extrusion → first aging treatment → second cold working → second aging treatment → third cold working forming.

[0006] Chinese patent document CN106591753B, "A Short-Process Preparation and Processing Technology for Copper-Chromium-Zirconium Alloy High-Speed ​​Railway Contact Wire," provides a contact wire with an alloy composition of Cu-(0.1~1.4)%Cr-(0.02~0.2)%Zr, and the sum of other elements is less than 0.2%. The preparation method is as follows: continuous casting → continuous solution treatment → rolling and drawing → continuous aging treatment → drawing and forming → continuous aging treatment.

[0007] Chinese patent document CN118942794A, "A Production Process for Preparing Copper-Chromium-Zrconium Contact Wire by Upward Drawing Method", provides a contact wire with an alloy composition of Cu-(0.1~1.5)%Cr-(0.02~0.2)%Zr, and the sum of other elements is less than or equal to 0.15%. The preparation method is as follows: upward continuous casting → extrusion → water-sealed solution treatment → aging treatment → peeling → cold working.

[0008] Chinese patent document CN109158562A, "A special contact wire for rigid contact network and its preparation method", provides a contact wire with an alloy composition of Cu-(0.2~0.9)%Cr-(0.02~0.2)%Zr, and the sum of other elements is less than or equal to 0.15%; the preparation method is: horizontal continuous casting-extrusion-cold rolling-heat treatment-drawing.

[0009] Chinese patent document CN104342575A, entitled "A Chromium-Zirconium-Copper Contact Wire for Electrified Railways and Its Processing Technology", provides a contact wire with an alloy composition of Cu-(0.3~0.7)%Cr-(0.1~0.35)%Zr, and the sum of other elements is less than or equal to 0.15%. The preparation method is: vacuum horizontal continuous casting-hot rolling-on-line solution treatment-peeling-cold rolling-aging-rolling pre-forming-drawing.

[0010] Chinese patent document CN104928603A, entitled "A Thermomechanical Treatment Production Process for a Long-Length Cu-Cr-Zr-Si Alloy Contact Wire," provides a contact wire with an alloy composition of Cu-(0.3~0.5)%Cr-(0.1~0.15)%Zr-(0.01~0.02)%Si. The preparation method is as follows: horizontal continuous casting-high frequency induction hot rolling-solution treatment-cold rolling-graded aging-drawing.

[0011] Chinese patent document CN 118098703A, "Preparation process of high-strength and high-conductivity Cu-Cr-Zr alloy contact wire", provides a contact wire with an alloy composition of Cu-(0.3~0.5)%Cr-(0.1~0.15)%Zr-(0.01~0.02)%Si; the preparation method is: continuous casting-continuous extrusion-multi-pass continuous extrusion-drawing-aging-finishing.

[0012] However, in the existing technology, Zr is difficult to replace in alloy contact wires. It does not solve the problem of Zr burn-off, the Zr yield is low, and it is difficult to control the composition uniformity of long rod blanks. Moreover, the existing alloy contact wire manufacturing process is complicated and has a long process flow, requiring at least 5 processes and up to 9 processes. Multiple heat treatments and processing lead to high energy consumption, long cycle time, and difficulty in controlling the consistency of product quality. Summary of the Invention

[0013] To address the aforementioned issues, this invention provides a Cu-Cr-X alloy contact wire that achieves Zr element substitution, reduces the number of processes and the use of expensive alloying elements, enables low-cost manufacturing of alloy contact wires, and ensures consistent product quality.

[0014] A Cu-Cr-X alloy contact wire, characterized in that: the components constituting the alloy contact wire body include Cu, Cr, X and unavoidable impurities, wherein the Cr content ranges from 0.3-0.6wt%, X is one or a mixture of two elements, Ti and Si, the unavoidable impurity content is less than 0.3wt%, and the balance is copper.

[0015] Its further features are: When the element X is only Ti, the content of X ranges from 0.03 to 0.06 wt%; when the element X is only Si, the content of X ranges from 0.05 to 0.08 wt%; when the element X is a mixture of Si and Ti, the content of Ti ranges from 0.02 to 0.04 wt% and the content of Si ranges from 0.08 to 0.11 wt%.

[0016] The alloy composition of the contact wire was designed, with trace amounts of at least one of the alloying elements Ti and Si added. This utilizes the solid solution strengthening and refining effect of Ti and Si in the Cu-Cr alloy to enhance the precipitated Cr phase. When Ti and Si are added together in a certain proportion, they can form intermetallic compounds, reducing electron scattering and improving the alloy's strength and conductivity. This allows for the substitution of Zr, saving the expensive Zr element, reducing the complexity of alloying element addition, and making the alloy composition easier to control. Furthermore, the added Si alloying element also improves the wear resistance and corrosion resistance of the contact wire.

[0017] A method for preparing a Cu-Cr-X alloy contact wire, characterized by comprising the following steps: S1, Electromagnetic + High-Power Ultrasonic Stirring Horizontal Continuous Casting; S2, high extrusion ratio continuous extrusion; S3, Low-temperature rapid aging; S4, three-pass cold drawing forming.

[0018] Its further features are: In step S1, one or two of electrolytic copper with a copper content greater than 99.95%, Cu10Cr master alloy, Cu30Ti and Cu10Si master alloy are smelted in a non-vacuum furnace. Then, the molten copper liquid is guided into a holding furnace and stirred by electromagnetic and high-power ultrasonic stirring to obtain a Φ18-22mm rod billet by horizontal continuous casting. In step S1, electromagnetic stirring and high-power ultrasonic stirring are performed in front of the horizontal continuous casting crystallizer. The electromagnetic stirrer has a frequency of 20-35Hz and a current of 50-100A; the ultrasonic vibration frequency is 20KHz and the vibration power is 800-1500W. In step S2, the Φ18-22mm rod blank obtained by continuous casting in step S1 is continuously extruded into a Φ16-18mm extruded rod blank. In step S2, the continuous extrusion die cavity expansion zone gradually expands to perform continuous extrusion with a large extrusion ratio; In step S3, the obtained Φ16-18mm extrusion rod blank is placed into an atmosphere-protected furnace, the aging temperature is set to 300-400℃, the temperature is increased for 0.5-1 hour, the temperature is held for 0.5-1 hour, and then cooled with the furnace. In step S4, the aged rod blank is drawn into a contact wire of a certain cross-sectional area through a giant drawing machine in three passes.

[0019] The contact wire preparation method of this invention involves only four steps. Electromagnetic and ultrasonic stirring technology agitates the liquid and semi-solid alloy at the solidification front, resulting in more uniform flow, heat transfer, and mass transfer of the molten metal during solidification. This leads to finer grain size in the cast billet, reducing defects such as porosity and segregation, and improving the quality of the continuously cast billet. The method fully utilizes the heat generated by the continuous extrusion equipment for online aging, achieving online recrystallization of the Cu-Cr-X alloy while reducing the time and temperature of subsequent aging treatments, thus reducing energy consumption and lowering manufacturing costs. Attached Figure Description

[0020] Figure 1 This is a simplified structural diagram of an electromagnetic + high-power ultrasonic stirring horizontal continuous casting crystallizer suitable for the preparation method of this invention; Figure 2 This is a microstructure diagram of the cross-section of a continuously cast billet when the corresponding alloy contact line of the present invention is without the participation of a stirrer; Figure 3 This is a microstructure diagram of the cross-section of the continuously cast billet after the corresponding alloy contact line of the present invention has been stirred by a stirrer. The names corresponding to the serial numbers in the diagram are as follows: Graphite mold 1, furnace lining 2, electromagnetic stirrer 3, ultrasonic stirrer 4, copper sleeve 5, billet 6. Detailed Implementation

[0021] A Cu-Cr-X alloy contact wire: The components constituting the alloy contact wire body include Cu, Cr, X and unavoidable impurities, wherein the Cr content ranges from 0.3-0.6 wt%, X is one or a mixture of two elements, Ti and Si, the unavoidable impurity content is less than 0.3 wt%, and the balance is copper.

[0022] When the element X is only Ti, the content of X ranges from 0.03 to 0.06 wt%; when the element X is only Si, the content of X ranges from 0.05 to 0.08 wt%; when the element X is a mixture of Si and Ti, the content of Ti ranges from 0.02 to 0.04 wt% and the content of Si ranges from 0.08 to 0.11 wt%.

[0023] The alloy composition of the contact wire was designed, with trace amounts of at least one of the alloying elements Ti and Si added. This utilizes the solid solution strengthening and refining effect of Ti and Si in the Cu-Cr alloy to enhance the precipitated Cr phase. When Ti and Si are added together in a certain proportion, they can form intermetallic compounds, reducing electron scattering and improving the alloy's strength and conductivity. This allows for the substitution of Zr, saving the expensive Zr element, reducing the complexity of alloying element addition, and making the alloy composition easier to control. Furthermore, the added Si alloying element also improves the wear resistance and corrosion resistance of the contact wire.

[0024] A method for preparing a Cu-Cr-X alloy contact wire, characterized by comprising the following steps: S1. Electromagnetic + High-Power Ultrasonic Stirring Horizontal Continuous Casting: Electrolytic copper with a copper content greater than 99.95%, Cu10Cr master alloy, Cu30Ti, and Cu10Si master alloy, or one or two of these, are melted in a non-vacuum furnace. The molten copper is then guided into a holding furnace, where it is horizontally cast to obtain a Φ18-22mm rod billet using electromagnetic + high-power ultrasonic stirring. Electromagnetic stirring and high-power ultrasonic stirring are performed before the horizontal continuous casting crystallizer. The electromagnetic stirrer has a frequency of 20-35Hz and a current of 50-100A; the ultrasonic vibration frequency is 20KHz and the vibration power is 800-1500W. S2. High extrusion ratio continuous extrusion: The Φ18-22mm rod blank obtained by continuous casting in step S1 is continuously extruded into a Φ16-18mm extruded rod blank. The continuous extrusion die cavity expansion zone gradually expands to carry out high extrusion ratio continuous extrusion. S3. Low-temperature rapid aging: The obtained Φ16-18mm extruded rod blank is placed in an atmosphere-protected furnace, the aging temperature is set to 300-400℃, the temperature is increased for 0.5-1 hour, held for 0.5-1 hour, and then cooled in the furnace. S4. Three-pass cold drawing forming: The aged rod blank is drawn into a contact line with a certain cross-sectional area in three passes by a giant drawing machine.

[0025] The structure of the electromagnetic + high-power ultrasonic stirring horizontal continuous casting crystallizer used in step S1 is shown below. Figure 1 It includes a graphite mold 1, a furnace lining 2, an electromagnetic stirrer 3, an ultrasonic stirrer 4, a copper sleeve 5, and a billet 6.

[0026] The following is based on the production of 150mm 2 Let's take the contact wire as an example for explanation.

[0027] Example 1: In addition to copper and impurities, the contact wire also contains 0.45 wt% Cr and 0.045 wt% Ti; Its preparation method is as follows: S1. Electromagnetic + high-power ultrasonic stirring horizontal continuous casting: Electrolytic copper with a copper content greater than 99.95%, Cu10Cr, and Cu30Ti master alloys are added to the melting furnace for non-vacuum melting. After uniform melting, samples are taken for measurement. Then, the molten copper liquid is guided into the holding furnace at a temperature of 1200±10℃, a continuous casting speed of 700mm / min, a cooling water flow rate of 25L / min, and the electromagnetic stirrer is set to a frequency of 20Hz and a current of 50A. The ultrasonic vibration frequency is 20KHz and the vibration power is 800W. The dual-flow horizontal continuous casting produces Φ20mm rod billets, each weighing 2500kg. S2. High extrusion ratio continuous extrusion: The Φ20mm rod billet obtained by continuous casting in step S1 is continuously extruded into a Φ18mm extruded rod billet. The continuous extrusion cavity mold and the preheated pure copper rod are placed in a holding furnace for preheating at a temperature of 500℃ for 90 min. The mold is then loaded. The extrusion speed is set to 4.0 r / min. The Cu-Cr-Ti alloy casting rod at room temperature is then placed into the extrusion press for extrusion to obtain an extruded rod billet with a diameter of 18 mm. S3. Low-temperature rapid aging: The obtained Φ18mm extrusion bar billet is placed in an atmosphere-protected furnace, the aging temperature is set to 300℃, the temperature is increased for 0.5 hours, the temperature is held for 0.5 hours, and then cooled with the furnace. S4. Three-pass cold drawing forming: The aging-treated extruded billet is drawn in three passes using a giant drawing machine to form a cross-sectional area of ​​150mm². 2 The contact wire was drawn at a speed of 0.3 m / s, with deformation per pass of 25%, 8%, and 7%.

[0028] Example 2: In addition to copper and impurities, the contact wire also contains 0.45 wt% Cr and 0.065 wt% Si. Its preparation method is as follows: S1. Electromagnetic + high-power ultrasonic stirring horizontal continuous casting: Electrolytic copper with a copper content greater than 99.95%, Cu10Cr, and Cu10Si master alloys are added to the melting furnace for non-vacuum melting. After uniform melting, samples are taken for measurement. Then, the molten copper liquid is guided into the holding furnace at a temperature of 1180±10℃. The continuous casting speed is 750mm / min, the cooling water flow rate is 25L / min, the electromagnetic stirrer frequency is set to 28Hz, and the current is 70A; the ultrasonic vibration frequency is 20KHz, and the vibration power is 1000W. The dual-flow horizontal continuous casting produces Φ20mm rod billets, each weighing 2500kg. S2. High extrusion ratio continuous extrusion: The Φ20mm rod billet obtained by continuous casting in step S1 is continuously extruded into a Φ18mm extruded rod billet. The continuous extrusion cavity mold and the preheated pure copper rod are placed in a holding furnace for preheating at a temperature of 500℃ for 90 min. The mold is loaded. The extrusion speed is set to 4.0 r / min. Then, the Cu-Cr-Si alloy casting rod at room temperature is placed in the extrusion press for extrusion to obtain a rod billet with a diameter of 18 mm. S3. Low-temperature rapid aging: The obtained Φ18mm extrusion bar billet is placed in an atmosphere-protected furnace, the aging temperature is set to 350℃, the temperature is increased for 0.6 hours, the temperature is held for 0.5 hours, and then cooled with the furnace. S4. Three-pass cold drawing forming: The aging-treated extruded billet is drawn in three passes using a giant drawing machine to form a cross-sectional area of ​​150mm². 2 The contact wire was drawn at a speed of 0.3 m / s, with deformation per pass of 25%, 8%, and 7%.

[0029] Example 3: In addition to copper and impurities, the contact wire also contains 0.45 wt% Cr, 0.095 wt% Si, and 0.03 wt% Ti. Its preparation method is as follows: S1. Electromagnetic + high-power ultrasonic stirring horizontal continuous casting: Electrolytic copper with a copper content greater than 99.95%, Cu10Cr, and Cu30Ti master alloys are added to the melting furnace for non-vacuum melting. After uniform melting, samples are taken for measurement. Then, the molten copper liquid is guided into the holding furnace at a temperature of 1250±10℃. The continuous casting speed is 650mm / min, the cooling water flow rate is 25L / min, the electromagnetic stirrer frequency is set to 35Hz, and the current is 85A; the ultrasonic vibration frequency is 20KHz, and the vibration power is 1250W. The dual-strand horizontal continuous casting produces Φ20mm rod billets, each weighing 2500kg. S2. High extrusion ratio continuous extrusion: The Φ20mm rod billet obtained by continuous casting in step S1 is continuously extruded into a Φ18mm extruded rod billet. The continuous extrusion cavity mold and the preheated pure copper rod are placed in a heat preservation furnace for preheating at a temperature of 500℃ for 90 min. The mold is loaded. The extrusion speed is set to 4.5r / min. Then, the Cu-Cr-Si-Ti alloy casting rod at room temperature is placed into the extrusion press for extrusion to obtain a rod billet with a diameter of 18 mm. S3. Low-temperature rapid aging: The Φ18mm extruded rod blank is placed in an atmosphere-protected furnace, the aging temperature is set to 400℃, the temperature is increased for 1 hour, and the temperature is held for 1 hour before cooling with the furnace. S4. Three-pass cold drawing forming: The aging-treated extruded billet is drawn in three passes using a giant drawing machine to form a cross-sectional area of ​​150mm². 2 The contact wire was drawn at a speed of 0.3 m / s, with deformation per pass of 25%, 8%, and 7%.

[0030] The electromechanical performance test data of the contact wires corresponding to the above three embodiments are shown in Table 1: Table 1 In addition, during the specific implementation, corresponding alloy metal wires without electromagnetic + high-power ultrasonic stirring were also obtained, and their cross-sectional microstructure diagrams are shown below. Figure 2 The cross-sectional microstructure diagrams corresponding to Embodiments 1-3 of the present invention are shown below. Figure 3 .

[0031] This invention utilizes alloy composition design to add trace amounts of alloying elements Ti and Si. The solid solution strengthening and refining effects of Ti and Si in Cu-Cr alloys enhance the precipitated Cr phase. When Ti and Si are added together in a specific ratio, they form intermetallic compounds, reducing electron scattering and improving the alloy's strength and conductivity. This allows for the substitution of Zr, saving on expensive Zr, reducing the complexity of alloying element addition, and making the alloy composition easier to control. Furthermore, the added Si also improves the wear resistance of the contact wire.

[0032] The contact wire preparation method of this invention involves only four steps. Electromagnetic and ultrasonic stirring technology agitates the liquid and semi-solid alloy at the solidification front, resulting in more uniform flow, heat transfer, and mass transfer of the molten metal during solidification, thereby achieving a finer grain size in the cast billet (see...). Figure 2 and Figure 3(Comparison) reduces defects such as porosity and segregation, improving the quality of continuously cast billets. Fully utilizing the heat generated by the continuous extrusion equipment for online aging not only achieves online recrystallization of the Cu-Cr-X alloy but also reduces the time and temperature of subsequent aging treatments, thereby reducing energy consumption and lowering manufacturing costs.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0034] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A Cu-Cr-X alloy contact wire, characterized in that: The components constituting the alloy contact wire include Cu, Cr, X, and unavoidable impurities. The Cr content ranges from 0.3 to 0.6 wt%, X is one or a mixture of Ti and Si, the unavoidable impurity content is less than 0.3 wt%, and the balance is copper.

2. The Cu-Cr-X alloy contact wire according to claim 1, characterized in that: When the element X is only Ti, the content of X ranges from 0.03 to 0.06 wt%; when the element X is only Si, the content of X ranges from 0.05 to 0.08 wt%; when the element X is a mixture of Si and Ti, the content of Ti ranges from 0.02 to 0.04 wt% and the content of Si ranges from 0.08 to 0.11 wt%.

3. A method for preparing a Cu-Cr-X alloy contact wire, characterized in that, It includes the following steps: S1, Electromagnetic + High-Power Ultrasonic Stirring Horizontal Continuous Casting; S2, high extrusion ratio continuous extrusion; S3, Low-temperature rapid aging; S4, three-pass cold drawing forming.

4. The method for preparing a Cu-Cr-X alloy contact wire according to claim 3, characterized in that: In step S1, one or two of electrolytic copper with a copper content greater than 99.95%, Cu10Cr master alloy, Cu30Ti and Cu10Si master alloy are smelted in a non-vacuum furnace. Then, the molten copper liquid is guided into a holding furnace and stirred by electromagnetic and high-power ultrasonic stirring to obtain a Φ18-22mm rod billet through horizontal continuous casting.

5. The method for preparing a Cu-Cr-X alloy contact wire according to claim 4, characterized in that: In step S1, electromagnetic stirring and high-power ultrasonic stirring are performed in front of the horizontal continuous casting crystallizer. The electromagnetic stirrer has a frequency of 20-35Hz and a current of 50-100A; the ultrasonic vibration frequency is 20KHz and the vibration power is 800-1500W.

6. The method for preparing a Cu-Cr-X alloy contact wire according to claim 4, characterized in that: In step S2, the Φ18-22mm rod blank obtained from continuous casting in step S1 is continuously extruded into a Φ16-18mm extruded rod blank.

7. The method for preparing a Cu-Cr-X alloy contact wire according to claim 6, characterized in that: In step S2, the continuous extrusion die cavity expansion zone gradually expands to perform continuous extrusion with a large extrusion ratio.

8. The method for preparing a Cu-Cr-X alloy contact wire according to claim 6, characterized in that: In step S3, the obtained Φ16-18mm extrusion rod blank is placed into an atmosphere-protected furnace, the aging temperature is set to 300-400℃, the temperature is increased for 0.5-1 hour, and the temperature is held for 0.5-1 hour before being cooled with the furnace.

9. The method for preparing a Cu-Cr-X alloy contact wire according to claim 3, characterized in that: In step S4, the aged billet is drawn in three passes using a giant drawing machine to form a cross-sectional area of ​​150 mm². 2 The contact line.

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