High-speed rail transit traction motor rotor assembly and preparation method thereof

Abstract

The application provides a high-speed rail transit traction motor rotor assembly and a preparation method thereof. The assembly is an end ring or a bar, and components of the assembly include 0.5-2% of Cr, 0.05-0.3% of Zr, 0.1-0.5% of Ag, 0.05-0.3% of Ti, and the balance of Cu in percentage of mass. The preparation method comprises the following steps: vacuum smelting, pouring, hot rolling, turning and cold rotary swaging of metal to obtain a rod; heating treatment of the rod, and then hot extrusion to obtain a flat strip; heating treatment of the flat strip, and then solid solution quenching in water to obtain a quenched flat strip; continuous diameter change cold drawing of the quenched flat strip to obtain a bar, or, continuous upsetting and elongation of the quenched flat strip after treatment at 850-950 DEG C, punching to obtain an end ring; aging treatment of the bar or the end ring. The traction motor rotor assembly provided by the application has high strength and high conductivity.

Description

Technical Field

[0001] This invention belongs to the field of advanced metal processing, specifically relating to a rotor assembly for a high-speed rail transit traction motor and its preparation method. Background Technology

[0002] The rotor end ring of a high-speed rail transit motor, as part of the rotor winding, connects the two ends of the conductor bars extending from the iron core in the outer circular slots, serving to conduct current. Therefore, the end ring of a high-speed rail transit traction motor not only requires good electrical and thermal conductivity but also a certain strength, especially a certain resistance to high-temperature softening, to prevent softening of the brazed end ring, which could lead to cracking during operation and a reduced service life. The conductor bars are installed in the rotor core slots, with their ends welded together by end rings to form a closed circuit. The closed conductor bars on the rotor will induce potential and current by cutting the magnetic lines of force of the stator magnetic field. The charged conductor bars will move in the magnetic field, thus rotating the motor rotor. Therefore, the conductor bars of a high-speed rail transit motor rotor must have good electrical and thermal conductivity. Furthermore, due to the high-speed rotation of the rotor, the conductor bars need to have a certain strength to prevent deformation and failure during rotor rotation. In addition, the conductor bars will heat up due to the electromagnetic field and current, so the material used for the conductor bars should also consider the issue of high-temperature softening. Against the backdrop of further acceleration in high-speed rail transit, higher requirements are placed on the material properties of the end rings and guide bars of high-speed rail traction motors, requiring them to have high strength and high conductivity.

[0003] Currently, the copper alloys used in high-speed rail traction motor rotor assemblies have undergone two stages of development: The first stage, low strength and high conductivity, mainly involved adding elements such as Ag, Cd, As, Te, and Rb to the copper alloy without significantly reducing its conductivity. This resulted in alloys with a conductivity of up to 90% IACS, but the mechanical properties were not ideal and could not meet usage requirements. This primarily involved mono- or binary alloy systems, mainly designed to meet the needs of new projects planned for high-speed railway main corridors, with a standard of 250 km / h and above (the standard could be appropriately lowered in areas with complex terrain, geology, and climate). The second stage, medium strength and medium conductivity, focused on improving alloy strength by slightly sacrificing some conductivity. This involved exploring multi-element alloying combined with subsequent heat treatment to improve alloy performance, resulting in medium-strength, medium-conductivity copper alloys with both mechanical and electrical properties. A typical alloy system is the Cu-Cr-Zr alloy, primarily designed for railways along densely populated urban areas, economically developed regions, and those connecting major cities, with a standard of 350 km / h.

[0004] However, when the speed of rail transit increases to 400 km / h, the starting and speed change of the motor will generate a larger torsional torque. With resistivity, yield strength, and softening temperature remaining constant, the strength of the material needs to be further improved; otherwise, the motor will suffer instantaneous torsional failure. However, neither low-strength, high-conductivity nor medium-strength, medium-conductivity copper alloys can fully meet the requirements for further speed increases in high-speed rail transit (above 400 km / h). Increasing strength reduces conductivity, and vice versa. This contradiction makes it impossible to obtain high-strength, high-conductivity copper alloys, thus failing to adequately meet the requirements for further speed increases in high-speed rail transit. Summary of the Invention

[0005] To address the problems of the prior art, this invention provides a high-speed rail transit traction motor rotor assembly and its manufacturing method, thereby solving the problems of strength, electrical conductivity, thermal conductivity, and high-temperature softening resistance of the traction motor rotor assembly, and providing a high-strength, high-conductivity traction motor rotor assembly to meet the requirements of further speed increases in current high-speed rail transit.

[0006] This invention is achieved through the following technical solution:

[0007] A rotor assembly for a high-speed rail transit traction motor, the assembly being an end ring or guide bar, comprising, by mass percentage: 0.5%-2% Cr, 0.05%-0.3% Zr, 0.1%-0.5% Ag, 0.05%-0.3% Ti, with the balance being Cu.

[0008] The method for manufacturing the rotor assembly of the high-speed rail transit traction motor includes the following steps:

[0009] (1) The metals corresponding to each element in the component are vacuum melted and then cast to obtain rod 1;

[0010] (2) The rod 1 is hot rolled, turned and cold forged in sequence to obtain the rod 2;

[0011] (3) Heat the rod 2 to 800-950℃ and keep it at that temperature, then perform hot extrusion to obtain a flat strip;

[0012] (4) Heat the flat strip to 900-1000℃ and keep it at that temperature, then quench it in water to obtain the quenched flat strip.

[0013] (5) The quenched flat strip is continuously cold-drawn with varying diameter to obtain a guide bar; or, the quenched flat strip is heated to 850-950℃ and kept at that temperature, then continuously upsetting and drawing several times, and punching holes to obtain an end ring.

[0014] (6) Aging treatment of the guide bar or end ring at 350-450℃.

[0015] Preferably, the specific process of step (1) is as follows: CuCr, CuAg, CuZr and CuTi intermediate alloys are obtained by vacuum melting, and the CuCr, CuAg, CuZr and CuTi intermediate alloys and metallic copper are batched and vacuum melted. The resulting melt is left to stand and then cast to obtain rod 1.

[0016] Furthermore, while the melt is settling, 0.05%-0.3% Ce by mass of the melt is added and stirred, and then the melt is cast to obtain rod 1.

[0017] Preferably, the specific process of step (2) is as follows: heat the rod 1 to 800-900℃ and keep it for 0.5-1h, then roll it to a diameter of 280-300mm, turn the surface of the rod 1 by 1-2mm, and then cold forge it to a diameter of 250-280mm.

[0018] Preferably, the specific process of step (3) is as follows: heat the rod 2 to 800-950℃, keep it at that temperature for 0.5-1h, and then perform hot extrusion treatment to form a flat strip. Reduce the maximum diameter to 70-80mm, remove the ends of the flat strip, and obtain the flat strip.

[0019] Preferably, in step (4), the heat preservation time is 0.5-1h.

[0020] Preferably, in step (5), solution treatment, annealing and polishing are performed during the continuous variable diameter cold drawing process.

[0021] Furthermore, in step (5), the solution temperature is 850-980℃ and the annealing temperature is 420-510℃.

[0022] Preferably, in step (6), the heat preservation time for aging treatment is 3.5-4.5h.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention relates to a high-speed rail transit traction motor rotor assembly using a Cu-Cr-Zr-Ag-Ti alloy material. This material not only features dispersed precipitated fine Cr phase reinforcement but also incorporates Ag. The addition of Ag forms complex CuAgZr precipitates, which, together with the matrix, form coherent and semi-coherent dispersed fine precipitates, further increasing material strength and reducing its susceptibility to cracking. Furthermore, Ag has a smaller impact on the matrix material compared to Zr. This material composition maintains the alloy at a high level of strength and electrical conductivity, exhibiting excellent electrical and thermal conductivity, strength, resistance to high-temperature softening, and fatigue resistance. This meets the requirements for copper alloy rotor components in traction motors as high-speed rail speeds increase.

[0025] This invention employs vacuum melting, forging, hot rolling, hot extrusion, solution treatment, pressure processing, and aging processes to prepare guide bars and end rings, thereby solving problems related to strength, electrical and thermal conductivity, and resistance to high-temperature softening. It also contributes to the development of safety, stability, and efficiency of high-speed trains.

[0026] Furthermore, the present invention first prepares CuCr, CuAg, CuZr, and CuTi master alloys, and then performs mixed smelting, which can lower the melting point, improve smelting efficiency, and save energy.

[0027] Furthermore, by adding rare earth elements, this invention reduces material impurities, refines grains, further improves material strength, and reduces crack sensitivity. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the rotor guide bar of the high-speed rail transit traction motor of the present invention;

[0029] Figure 2 This is a schematic diagram of the rotor end ring of the high-speed rail transit traction motor involved in the present invention;

[0030] Figure 3 This is a flowchart of the process of the present invention. Detailed Implementation

[0031] To further understand the present invention, the present invention will be described below with reference to embodiments. These descriptions are only for further explaining the features and advantages of the present invention and are not intended to limit the claims of the present invention.

[0032] refer to Figure 1 and Figure 2 The present invention relates to a high-speed rail transit traction motor rotor assembly, which is an end ring or guide bar, and its material is a Cu-Cr-Zr-Ag-Ti alloy. By mass percentage, the Cu-Cr-Zr-Ag-Ti alloy composition includes: 0.5%-2% Cr, 0.05%-0.3% Zr, 0.1%-0.5% Ag, 0.05%-0.3% Ti, and the balance being Cu.

[0033] refer to Figure 3 The processing technology method for high-speed rail transit traction motor rotor assembly of the present invention mainly includes the following steps:

[0034] (1) Vacuum melting: The metals corresponding to each element in the component are vacuum melted and then cast into rods 1 with a diameter of 330-365mm;

[0035] The preferred process is as follows: First, CuCr (Cr: 10wt%-30wt%), CuAg (Ag: 5wt%-15wt%), CuZr (Zr: 35wt%-65wt%), and CuTi (Ti: 5wt%-10wt%) master alloys are obtained by vacuum melting. The impurity content in the raw materials used should not exceed 0.01%, and the obtained master alloys should be free of defects such as pores and inclusions. The master alloys and high-purity electrolytic copper plates are mixed and vacuum melted at 1250-1550℃. The resulting melt is allowed to stand and finally cast into rods 1 with a diameter of 330-365mm and a length of 1.5-3m.

[0036] The present invention may also optionally include: adding 0.05%-0.3% Ce by mass of the melt while it is settling and stirring, based on the total mass of the melt. The Ce content should not be too high, otherwise the alloy hardness will be too high, but the Ce content should not be too low either, otherwise the impurity removal and refining effect will be poor; finally, it is cast into a rod 1 with a diameter of 330-365mm and a length of 1.5-3m.

[0037] (2) Turning, cold forging and hot rolling: The rod 1 is hot rolled, turned and cold forged in sequence to obtain the rod 2;

[0038] The preferred process is as follows: First, heat the rod 1 to 800-900℃ and hold for 0.5-1h, then roll it to a diameter of 280-300mm, turn the surface of the rod 1 by 1-2mm, then cold forge it to a diameter of 250-280mm, and then cut and saw it to a length of not less than 200mm, with no cracks on the surface of the rod.

[0039] (3) Hot extrusion: Heat the rod 2 to 800-950℃ and keep it at that temperature for 0.5-1h, then perform hot extrusion treatment, and then remove the two ends to obtain a flat strip;

[0040] The preferred process is as follows: heat the rod 2 to 800-950℃. Too high a temperature will result in low strength, and too low a temperature will result in material cracking. After holding the temperature for 0.5-1h, transfer it to the extrusion cylinder for hot extrusion treatment to form a flat strip. The maximum diameter is reduced to 70-80mm. The surface of the flat strip is free of defects. Remove the ends of the flat strip.

[0041] (4) Online solution quenching

[0042] The preferred process is as follows: heat the flat strip to 900-1000℃ and hold it at that temperature for 0.5-1 hour, then quench it in water to obtain the quenched flat strip. Here, the temperature should not be too high or too low, and should be maintained at 900-1000℃. If the temperature exceeds this range, the strength will be reduced, the grains will become coarse, and the grain boundaries will melt. If the temperature is below this range, the structure will be uneven, which will lead to internal stress cracking.

[0043] (5) Pressure processing

[0044] The specific process is as follows: the quenched flat strip is continuously cold-drawn with varying diameter, and solution treatment, annealing and polishing are carried out in between. Finally, it is drawn into guide bars of different specifications to meet the needs of traction motors. The solution treatment temperature is 850-980℃ and the annealing temperature is 420-510℃.

[0045] Alternatively, the quenched flat strip is heated to 850-950℃ in a heating chamber and held for 1-1.5 hours. It is then continuously upsetting and drawing three times on a forging machine. A hole is punched in the middle using a die to obtain an end ring. The product is then shaped using a forging hammer and a die, and the surface is free of defects after peeling.

[0046] (6) Timeliness processing

[0047] The preferred process is as follows: aging treatment is performed at 350-450℃ under a protective atmosphere, followed by precision machining after holding at that temperature for 3.5-4.5 hours. The aging treatment temperature should not be too high or too low. Too high a temperature can easily cause the precipitated phase to increase in size, reducing the reinforcing effect of the strengthening phase and thus lowering the product strength. Too low a temperature can lead to incomplete precipitation and growth of the precipitated phase, increasing the risk of product cracking and reducing toughness.

[0048] Specific implementation examples are given below:

[0049] Example 1

[0050] In this embodiment, the rotor assembly of the high-speed rail traction motor is a guide bar, and its components, by mass percentage, include: 0.6% Cr, 0.06% Zr, 0.3% Ag, 0.1% Ti, and the balance being Cu.

[0051] Step 1: Obtain a CuCr (Cr: 10wt%), CuAg (Ag: 5wt%), CuZr (Zr: 65wt%), and CuTi (Ti: 10wt%) master alloy by vacuum melting. Mix the master alloy with high-purity electrolytic copper plate and vacuum melt. Add 0.05wt.%Ce to the melt while it is settling and stir. Finally, cast it into a rod 1 with a diameter of 330mm and a length of 1.5m.

[0052] Step 2: First, heat rod 1 to 800℃ and hold for 1 hour, then roll it to a diameter of 300mm, turn the surface of rod 1 by 1mm, then cold forge it to a diameter of 280mm, and then saw it to obtain rod 2;

[0053] Step 3: Heat rod 2 to 850℃, keep it at that temperature for 1 hour, then transfer it to the extrusion cylinder for hot extrusion to form a flat strip. Reduce the maximum diameter to 70mm and remove the ends of the flat strip.

[0054] Step 4: Heat the flat strip to 900℃, hold for 1 hour, and then quench it in water for solution hardening.

[0055] Step 5: The solution-quenched flat strip is continuously cold-drawn with varying diameters, with intermediate steps of solution annealing and polishing, and finally drawn into guide bars of different specifications to meet the needs of traction motors.

[0056] Step 6: The guide bar is aged at 400℃ under a protective atmosphere and then precision machined after holding at that temperature for 3.5 hours.

[0057] Example 2

[0058] In this embodiment, the rotor assembly of the high-speed rail traction motor is a guide bar, and its components, by mass percentage, include: 0.3% Cr, 0.06% Zr, 0.3% Ag, 0.1% Ti, and the balance being Cu.

[0059] Step 1: Obtain a CuCr (Cr: 12wt%), CuAg (Ag: 6wt%), CuZr (Zr: 60wt%), and CuTi (Ti: 9wt%) master alloy by vacuum melting. Mix the master alloy with high-purity electrolytic copper plate and vacuum melt. Add 0.1wt.% Ce to the melt while it is settling and stir. Finally, cast it into a rod 1 with a diameter of 340mm and a length of 2m.

[0060] Step 2: First, heat rod 1 to 900℃ and hold for 0.5h, then roll it to a diameter of 290mm, turn the surface of rod 1 by 2mm, then cold forge it to a diameter of 270mm, and then saw it to obtain rod 2;

[0061] Step 3: Heat rod 2 to 850℃, keep it at that temperature for 1 hour, then transfer it to the extrusion cylinder for hot extrusion to form a flat strip. Reduce the maximum diameter to 75mm and remove the ends of the flat strip.

[0062] Step 4: Heat the flat strip to 900℃, hold for 1 hour, and then quench it in water for solution hardening.

[0063] Step 5: The solution-quenched flat strip is continuously cold-drawn with varying diameters, undergoing solution annealing and polishing in between, and finally drawn into guide bars of different specifications to meet the needs of traction motors.

[0064] Step 6: The guide bar is aged at 400℃ under atmospheric protection and then precision machined after 4 hours of heat preservation.

[0065] Example 3

[0066] In this embodiment, the rotor assembly of the high-speed rail traction motor is a guide bar, and its components, by mass percentage, include: 0.6% Cr, 0.06% Zr, 0.3% Ag, 0.1% Ti, and the balance being Cu.

[0067] Step 1: Obtain a CuCr (Cr: 14wt%), CuAg (Ag: 7wt%), CuZr (Zr: 55wt%), and CuTi (Ti: 8wt%) master alloy by vacuum melting. Mix the master alloy with high-purity electrolytic copper plate and vacuum melt. Add 0.2wt.% Ce to the melt while it is settling and stir. Finally, cast it into a rod 1 with a diameter of 350mm and a length of 3m.

[0068] Step 2: First, heat rod 1 to 850℃ and hold for 1 hour, then roll it to a diameter of 280mm, turn the surface of rod 1 by 1mm, then cold forge it to a diameter of 250mm, and then saw it to obtain rod 2;

[0069] Step 3: Heat rod 2 to 900℃, keep it at that temperature for 1 hour, then transfer it to the extrusion cylinder for hot extrusion to form a flat strip. Reduce the maximum diameter to 80mm and remove the ends of the flat strip.

[0070] Step 4: Heat the flat strip to 900℃, hold for 1 hour, and then quench it in water for solution hardening.

[0071] Step 5: The solution-quenched flat strip is continuously cold-drawn and deformed with varying diameters, with intermediate steps including solution annealing and polishing, and finally drawn into guide bars of different specifications to meet the needs of traction motors.

[0072] Step 6: The guide bar is aged at 400℃ under a protective atmosphere and then precision machined after holding at that temperature for 4.5 hours.

[0073] Example 4

[0074] In this embodiment, the rotor assembly of the high-speed rail transit traction motor is an end ring, and its components, by mass percentage, include: 0.6% Cr, 0.06% Zr, 0.3% Ag, 0.1% Ti, and the balance being Cu.

[0075] Step 1: Obtain a CuCr (Cr: 18wt%), CuAg (Ag: 8wt%), CuZr (Zr: 50wt%), and CuTi (Ti: 8wt%) master alloy by vacuum melting. Mix the master alloy with high-purity electrolytic copper plate and vacuum melt. Add 0.25wt.%Ce to the melt while it is settling and stir. Finally, cast it into a rod 1 with a diameter of 365mm and a length of 2m.

[0076] Step 2: First, heat rod 1 to 860℃ and hold for 1 hour, then roll it to a diameter of 300mm, turn the surface of rod 1 by 2mm, then cold forge it to a diameter of 260mm, and then saw it to obtain rod 2;

[0077] Step 3: Heat rod 2 to 850℃, keep it at that temperature for 1 hour, then transfer it to the extrusion cylinder for hot extrusion to form a flat strip. Reduce the maximum diameter to 75mm and remove the ends of the flat strip.

[0078] Step 4: Heat the flat strip to 950℃, hold for 1 hour, and then quench it in water for solution hardening.

[0079] Step 5: Heat the solution-quenched flat strip to 900℃ in a heating box and hold for 1 hour. Then, continuously uplift and draw it three times on a forging machine. Punch a hole in the middle through a die to obtain an end ring.

[0080] Step 6: The end ring is aged at 400℃ under a protective atmosphere and then precision machined after holding at that temperature for 3.5 hours.

[0081] Example 5

[0082] In this embodiment, the rotor assembly of the high-speed rail transit traction motor is an end ring, and its components, by mass percentage, include: 0.6% Cr, 0.06% Zr, 0.3% Ag, 0.1% Ti, and the balance being Cu.

[0083] Step 1: Obtain a CuCr (Cr: 20wt%), CuAg (Ag: 9wt%), CuZr (Zr: 45wt%), and CuTi (Ti: 8wt%) master alloy by vacuum melting. Mix the master alloy with high-purity electrolytic copper plate and vacuum melt. Add 0.3wt.% Ce to the melt while it is settling and stir. Finally, cast it into a rod 1 with a diameter of 350mm and a length of 2m.

[0084] Step 2: First, heat rod 1 to 850℃ and hold for 1 hour, then roll it to a diameter of 300mm, turn the surface of rod 1 by 1mm, then cold forge it to a diameter of 260mm, and then saw it to obtain rod 2;

[0085] Step 3: Heat rod 2 to 850℃, keep it at that temperature for 1 hour, then transfer it to the extrusion cylinder for hot extrusion to form a flat strip. Reduce the maximum diameter to 80mm and remove the ends of the flat strip.

[0086] Step 4: Heat the flat strip to 900℃, hold for 1 hour, and then quench it in water for solution hardening.

[0087] Step 5: Heat the solution-quenched flat strip to 900℃ in a heating box and hold for 1.5h. Then, continuously uplift and draw it three times on a forging machine. Finally, punch a hole in the middle through a die to obtain an end ring.

[0088] Step 6: The end ring is aged at 450℃ under a protective atmosphere and then precision machined after holding at that temperature for 4.5 hours.

[0089] Example 6

[0090] In this embodiment, the rotor assembly of the high-speed rail traction motor is a guide bar, and its components, by mass percentage, include: 1% Cr, 0.3% Zr, 0.1% Ag, 0.3% Ti, and the balance being Cu.

[0091] Step 1: Obtain a CuCr (Cr: 23wt%), CuAg (Ag: 11wt%), CuZr (Zr: 40wt%), and CuTi (Ti: 7wt%) master alloy by vacuum melting. Mix the master alloy with high-purity electrolytic copper plate and vacuum melt. Add 0.05wt.%Ce to the melt while it is settling and stir. Finally, cast it into a rod 1 with a diameter of 330mm and a length of 1.5m.

[0092] Step 2: First, heat rod 1 to 800℃ and hold for 1 hour, then roll it to a diameter of 300mm, turn the surface of rod 1 by 1mm, then cold forge it to a diameter of 280mm, and then saw it to obtain rod 2;

[0093] Step 3: Heat rod 2 to 850℃, keep it at that temperature for 1 hour, then transfer it to the extrusion cylinder for hot extrusion to form a flat strip. Reduce the maximum diameter to 70mm and remove the ends of the flat strip.

[0094] Step 4: Heat the flat strip to 900℃, hold for 1 hour, and then quench it in water for solution hardening.

[0095] Step 5: The solution-quenched flat strip is continuously cold-drawn with varying diameters, with intermediate steps of solution annealing and polishing, and finally drawn into guide bars of different specifications to meet the needs of traction motors.

[0096] Step 6: The guide bar is aged at 400℃ under a protective atmosphere and then precision machined after holding at that temperature for 3.5 hours.

[0097] Example 7

[0098] In this embodiment, the rotor assembly of the high-speed rail transit traction motor is a guide bar, and its components, by mass percentage, include: 0.5% Cr, 0.2% Zr, 0.5% Ag, 0.2% Ti, and the balance being Cu.

[0099] Step 1: Obtain a CuCr (Cr: 26wt%), CuAg (Ag: 13wt%), CuZr (Zr: 39wt%), and CuTi (Ti: 6wt%) master alloy by vacuum melting. Mix the master alloy with high-purity electrolytic copper plate and vacuum melt. Add 0.05wt.%Ce to the melt while it is settling and stir. Finally, cast it into a rod 1 with a diameter of 330mm and a length of 1.5m.

[0100] Step 2: First, heat rod 1 to 800℃ and hold for 1 hour, then roll it to a diameter of 300mm, turn the surface of rod 1 by 1mm, then cold forge it to a diameter of 280mm, and then saw it to obtain rod 2;

[0101] Step 3: Heat rod 2 to 850℃, keep it at that temperature for 1 hour, then transfer it to the extrusion cylinder for hot extrusion to form a flat strip. Reduce the maximum diameter to 70mm and remove the ends of the flat strip.

[0102] Step 4: Heat the flat strip to 900℃, hold for 1 hour, and then quench it in water for solution hardening.

[0103] Step 5: The solution-quenched flat strip is continuously cold-drawn with varying diameters, with intermediate steps of solution annealing and polishing, and finally drawn into guide bars of different specifications to meet the needs of traction motors.

[0104] Step 6: The guide bar is aged at 400℃ under a protective atmosphere and then precision machined after holding at that temperature for 3.5 hours.

[0105] Example 8

[0106] In this embodiment, the rotor assembly of the high-speed rail transit traction motor is a guide bar, and its components, by mass percentage, include: 2% Cr, 0.05% Zr, 0.4% Ag, 0.05% Ti, and the balance being Cu.

[0107] Step 1: Obtain a CuCr (Cr: 30wt%), CuAg (Ag: 15wt%), CuZr (Zr: 35wt%), and CuTi (Ti: 5wt%) master alloy by vacuum melting. Mix the master alloy with high-purity electrolytic copper plate and vacuum melt. Add 0.05wt.%Ce to the melt while it is settling and stir. Finally, cast it into a rod 1 with a diameter of 330mm and a length of 1.5m.

[0108] Step 2: First, heat rod 1 to 800℃ and hold for 1 hour, then roll it to a diameter of 300mm, turn the surface of rod 1 by 1mm, then cold forge it to a diameter of 280mm, and then saw it to obtain rod 2;

[0109] Step 3: Heat rod 2 to 850℃, keep it at that temperature for 1 hour, then transfer it to the extrusion cylinder for hot extrusion to form a flat strip. Reduce the maximum diameter to 70mm and remove the ends of the flat strip.

[0110] Step 4: Heat the flat strip to 900℃, hold for 1 hour, and then quench it in water for solution hardening.

[0111] Step 5: The solution-quenched flat strip is continuously cold-drawn with varying diameters, with intermediate steps of solution annealing and polishing, and finally drawn into guide bars of different specifications to meet the needs of traction motors.

[0112] Step 6: The guide bar is aged at 400℃ under a protective atmosphere and then precision machined after holding at that temperature for 3.5 hours.

[0113] The components (guide strips or end rings) obtained in Examples 1-8 were subjected to performance tests, and the results are shown in Table 1.

[0114] Table 1. Component performance obtained in Examples 1-5

[0115]

[0116] As can be seen from Table 1, the product prepared by this invention has both high strength and electrical conductivity, indicating that the alloy of this invention can simultaneously achieve both high conductivity and high strength, thus obtaining a high-strength, high-conductivity alloy that can meet the material requirements when the speed of rail transit increases to 400 km / h. The product prepared in Example 1 of this invention exhibits the best performance.

Claims

1. A method for manufacturing a rotor assembly of a high-speed rail transit traction motor, characterized in that, The high-speed rail transit traction motor rotor assembly is an end ring or guide bar. By mass percentage, the assembly comprises: 0.5%-2% Cr, 0.05%-0.3% Zr, 0.1%-0.5% Ag, 0.05%-0.3% Ti, with the balance being Cu. The preparation method includes the following steps: (1) The metals corresponding to each element in the component are vacuum melted and then cast to obtain rod 1; (2) The rod 1 is hot rolled, turned and cold forged in sequence to obtain the rod 2; (3) Heat the rod 2 to 800-950℃ and keep it at that temperature, then perform hot extrusion to obtain a flat strip; (4) Heat the flat strip to 900-1000℃ and keep it at that temperature, then quench it in water to obtain the quenched flat strip; (5) The quenched flat strip is continuously cold-drawn with varying diameter to obtain a guide bar; or, the quenched flat strip is heated to 850-950℃ and kept at that temperature, then continuously upset and drawn several times, and punched to obtain an end ring; (6) Aging treatment of the guide bar or end ring at 350-450℃.

2. The method for preparing a high-speed rail transit traction motor rotor assembly according to claim 1, characterized in that, The specific process of step (1) is as follows: CuCr, CuAg, CuZr and CuTi intermediate alloys are obtained by vacuum melting. The CuCr, CuAg, CuZr and CuTi intermediate alloys and metallic copper are batched and vacuum melted. The resulting melt is left to stand and then cast to obtain rod 1.

3. The method for preparing a high-speed rail transit traction motor rotor assembly according to claim 2, characterized in that, When the melt is allowed to stand, add 0.05%-0.3% Ce by mass of the melt and stir, then pour to obtain rod 1.

4. The method for preparing a high-speed rail transit traction motor rotor assembly according to claim 1, characterized in that, The specific process of step (2) is as follows: heat the rod 1 to 800-900℃ and keep it for 0.5-1h, then roll it to a diameter of 280-300mm, turn the surface of the rod 1 by 1-2mm, and then cold forge it to a diameter of 250-280mm.

5. The method for preparing a high-speed rail transit traction motor rotor assembly according to claim 1, characterized in that, Step (3) is as follows: heat the rod 2 to 800-950℃, keep it at that temperature for 0.5-1h, and then perform hot extrusion to form a flat strip. Reduce the maximum diameter to 70-80mm, remove the ends of the flat strip, and obtain the flat strip.

6. The method for preparing a high-speed rail transit traction motor rotor assembly according to claim 1, characterized in that, In step (4), the heat preservation time is 0.5-1h.

7. The method for preparing a high-speed rail transit traction motor rotor assembly according to claim 1, characterized in that, In step (5), solution treatment, annealing and polishing are performed during the continuous variable diameter cold drawing process.

8. The method for preparing a high-speed rail transit traction motor rotor assembly according to claim 7, characterized in that, In step (5), the solution temperature is 850-980℃ and the annealing temperature is 420-510℃.

9. The method for preparing a high-speed rail transit traction motor rotor assembly according to claim 1, characterized in that, In step (6), the heat preservation time for aging treatment is 3.5-4.5h.

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