Equipment and method for continuously extruding large-diameter high-strength copper-magnesium alloy bars

Abstract

The present invention relates to an apparatus for continuously extruding large-diameter, high-strength copper-magnesium alloy rods. The apparatus comprises an extrusion wheel, a compacting wheel, an expansion forming device, a water trough, and a take-up device. A feed rod enters between the extrusion wheel and the compacting wheel, is fed by the extrusion wheel into the expansion forming device for continuous extrusion to obtain a large-diameter extruded rod. The extruded rod is cooled in the water trough and then wound onto the take-up device. The present invention achieves continuous extrusion of large-diameter, high-strength copper-magnesium alloy extruded rods by lengthening the expansion zone length of the cavity itself, optimizing the right-angle channel structure, and increasing the secondary expansion angle. This solves the problems of non-filling, cracks in the extruded rods, material shortages, high extruder load, and difficulty in demolding that occur when extruding large-diameter copper-magnesium alloy extruded rods. This enables the continuous production of high-strength copper-magnesium alloy contact wire extruded rods with a magnesium content of 0.3-0.7% and a diameter of 30-45 mm.

Description

Technical Field

[0001] The present invention relates to the technical field of metal extrusion molding, and in particular to equipment and a method for continuously extruding large-diameter high-strength copper-magnesium alloy bars. Background Art

[0002] Current copper and copper alloy contact wires can be classified by material into four categories: pure copper, copper-silver alloy, copper-tin alloy, and copper-magnesium alloy. These are suitable for electric locomotives operating at speeds of 350 km / h or less. Their processing generally involves continuous casting followed by continuous extrusion and drawing. With technological advancements, research on high-speed railways is deepening both domestically and internationally, and high-speed trains are expected to operate at increasingly higher speeds. To ensure the smooth operation of high-speed trains at these higher speeds, high-strength contact wires are essential. In recent years, research on high-strength contact wires has primarily focused on copper-chromium-zirconium contact wires. However, these wires still face numerous challenges in terms of long-length drawing and stable performance. Current copper-magnesium alloy contact wires have low tensile strength and cannot meet the higher speed requirements of electric locomotives. However, there is no industry research on the development of high-strength copper-magnesium alloy contact wires. Therefore, this patented invention aims to develop an extended forming process and tooling for the continuous extrusion of large-diameter, high-strength copper-magnesium alloy bars for the production of high-strength copper-magnesium alloy contact wires.

[0003] Chinese patent CN208680200U discloses a combined mold cavity for continuous extrusion molding of large-diameter rods, including a cavity body and a cavity cover, wherein the cavity body and the cavity cover are respectively provided with a feed port and a discharge port; a mold cavity is formed between the cavity body and the cavity cover, an extrusion die is fixedly embedded in the mold cavity, a sizing belt is formed in the extrusion die, and a trumpet cavity is provided on one side of the extrusion die; a plastic block is tightly arranged in the trumpet cavity; a molding pad is embedded in the mold cavity, and a guide groove is formed in the molding pad; the molding pad includes a first molding pad and a second molding pad, and the guide groove includes a first guide groove and a second guide groove.

[0004] Chinese patent CN203253761U discloses an expansion forming device for continuously extruding large-section copper rods, including a cavity, wherein the cavity includes a cavity panel and a cover plate, and the cavity panel and the cover plate are fixedly connected to form an expansion cavity at the connection; a gasket and a mold are installed in the expansion cavity in sequence.

[0005] The above technical solution is an expansion forming device developed for aluminum and aluminum alloys, copper and copper alloys with good plasticity and easy expansion. It is not suitable for high-strength copper-magnesium alloys with high strength, poor plasticity and difficult filling. Therefore, the present invention targets high-strength copper-magnesium alloys with poor plasticity and difficulty in expansion, and often causes problems such as non-filling, cracks in the extrusion rod, material shortages, and heavy load on the extruder during continuous extrusion. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide an apparatus and method for continuously extruding large-diameter high-strength copper-magnesium alloy rods. By lengthening the expansion zone length of the cavity itself, optimizing the right-angle channel structure, and increasing the secondary expansion angle, continuous extrusion of large-diameter high-strength copper-magnesium alloy extrusion rods is achieved. The problems of non-filling, cracks in the extrusion rods, material shortages, high extruder load, and difficult demolding that occur when extruding large-diameter copper-magnesium alloy extrusion rods are solved, and the continuous production of high-strength copper-magnesium alloy extrusion rods for contact lines with a magnesium content of 0.3-0.7% and a diameter of 30-45 mm is achieved.

[0007] The object of the present invention is achieved like this:

[0008] A device for continuously extruding large-diameter high-strength copper-magnesium alloy bars includes an extrusion wheel, a compaction wheel, an expansion forming device, a water trough, and a take-up device. A feed rod enters between the extrusion wheel and the compaction wheel, and is fed by the extrusion wheel into the expansion forming device for continuous extrusion to obtain a large-diameter extruded rod. The extruded rod is cooled in the water trough and then wound on the take-up device.

[0009] Preferably, the expansion molding device includes a cavity and a cavity cover, a cavity is formed between the cavity and the cavity cover, a gasket and a mold are embedded in the cavity, the left side of the gasket is connected to the cavity expansion area, the cavity expansion area is connected to the leftmost feed port of the cavity, the interior of the gasket is conical, its large diameter side is connected to the cavity expansion area, and the diameter size is the same as the diameter at the connection with the expansion area, the small diameter side is connected to the mold, and the diameter size is larger than the mold hole size, and the right side of the mold is the discharge port.

[0010] Preferably, a material stop block is provided on the left side of the cavity, and the working plane of the material stop block is higher than the lower plane of the feed port.

[0011] Preferably, the cavity expansion areas are, from left to right, a right-angle channel area A, a tapered expansion area B and a parallel expansion area C.

[0012] Preferably, the water trough is provided at the discharge port of the expansion molding device, the water trough is provided with a hanging spray device corresponding to the discharge port of the expansion molding device, and the water trough is provided with a plurality of spray devices along the length direction of the extrusion rod.

[0013] Preferably, the extrusion wheel is cooled by an extrusion wheel cooling control device, the suspended spray device and the spray device are controlled by an extrusion rod cooling control device, and the extrusion wheel cooling control device and the extrusion rod cooling control device are independently provided.

[0014] A method for continuously extruding large-diameter high-strength copper-magnesium alloy bars, using the above-mentioned equipment, comprises the following steps:

[0015] Step 1: First, turn on the extrusion wheel cooling control device, feed the short material before extrusion, and then feed the copper-magnesium alloy upper guide rod with low magnesium content. After it is well filled, finally feed the high-strength copper-magnesium alloy upper guide rod;

[0016] Step 2: Each feed rod moves stably together with the extrusion wheel under the action of the compacting wheel. When the feed rod encounters the blocking block, it changes direction and enters the expansion molding device from the feed port. After the expansion molding is completed under the joint action of the cavity expansion area, the gasket and the mold, the extrusion rod enters the water tank from the discharge port, the extrusion rod cooling device is turned on, and the hanging spray device and the spray device are used to fully cool the extrusion rod. The cooled large-diameter extrusion rod is wound on the take-up device.

[0017] Preferably, in step one, the expansion molding device is heated to 550-650°C before extrusion and kept warm for 60 minutes; 5-10 short rods are heated to 800-900°C, and at least 20m of copper-magnesium alloy upper guide rods with a magnesium content of 0.05-0.10% are prepared; after they are filled, high-strength copper-magnesium alloy upper guide rods with a magnesium content of 0.5-0.7% are fed.

[0018] Preferably, the pressing amount of the compacting wheel is controlled at 3-6 mm, the fitting clearance between the expansion molding device and the extrusion wheel is controlled at 0.4-1 mm, the speed of the extrusion wheel is 1.8-5 r / min, and the extrusion ratio is 1.44-3.24.

[0019] Preferably, the inlet temperature of the extrusion wheel cooling water is controlled at 15-30°C, the inlet temperature of the copper rod cooling water is controlled at 10-20°C and a spray cooling method is adopted, and the water flow rate of both is 0-6m³ / h.

[0020] The beneficial effects of the present invention are:

[0021] (1) Achieve continuous extrusion of large-diameter, high-strength copper-magnesium alloy extruded rods;

[0022] (2) The extrusion wheel cooling control device and the extrusion rod cooling device are independently set, which is easy to adjust and ensures that the extrusion tooling is in a stable high-temperature production environment. At the same time, it can effectively cool the copper rod to prevent the grain growth inside the copper rod;

[0023] (3) Before connecting the high-strength copper-magnesium alloy upper guide rod, after feeding the heated short material, the copper-magnesium alloy upper guide rod with good plasticity and easy expansion and low magnesium content is used to fill the cavity. On the one hand, the extrusion tooling can be heated in a short time to form a stable temperature field, which promotes the plastic expansion of the high-strength copper-magnesium alloy upper guide rod. On the other hand, when the high-strength copper-magnesium alloy upper guide rod is extruded, the copper-magnesium alloy with low content already filled in the cavity plays a good blocking role, so that the high-strength copper-magnesium alloy material is fully filled in the cavity.

[0024] (4) By lengthening the expansion zone of the cavity itself to increase the extrusion stroke, it not only solves the problem of high-strength copper-magnesium alloy being difficult to fill, but also ensures the integrity of the cavity and increases the bearing capacity and service life of the cavity;

[0025] (5) The right-angle channel area in the feed port and the cavity expansion area is an eccentric structure, and the starting and ending positions of the upper and lower right-angle channels are not on the same vertical plane, which avoids the unbalanced force phenomenon of the copper-magnesium alloy material in the right-angle channel, reduces the difference in upper and lower flow velocities, and improves the quality of the extrusion rod;

[0026] (6) Two expansion angles are provided in the second area of ​​the cavity expansion zone, making it easier to fill the high-strength copper-magnesium alloy with poor plasticity;

[0027] (7) The third area of ​​the cavity expansion zone is parallel to the expansion zone and a certain inclination angle is set to facilitate demoulding;

[0028] (8) The working plane of the blocking block is higher than the lower plane of the feed port, increasing the filling space of the expansion area;

[0029] (9) The copper-magnesium alloy contact wire produced by continuous extrusion of the large-diameter high-strength copper-magnesium alloy extruded rod produced by the present invention can achieve a strength of more than 600 MPa and a conductivity of more than 72% IACS. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the present invention.

[0031] Figure 2 for Figure 1 A partial enlarged view of .

[0032] Figure 3 Schematic diagram of the structure of the expansion molding device.

[0033] Figure 4 Schematic diagram of the structure of the cavity expansion area.

[0034] Among them: extrusion wheel 1; feed rod 2; compacting wheel 3; expansion molding device 4; water trough 5; spray device 6; water outlet 7; extrusion rod 8; take-up device 9; scraper 10; extrusion wheel cooling control device 11; extrusion rod cooling control device 12; suspended spray device 13; feed port 41; cavity expansion area 42; cavity 43; cavity cover 44; gasket 45; mold 46; discharge port 47; bolt 48; blocking block 49. DETAILED DESCRIPTION

[0035] See also Figure 1-4The present invention relates to equipment for continuously extruding large-diameter, high-strength copper-magnesium alloy bars, comprising an extrusion wheel 1, a feed rod 2, a compacting wheel 3, an expansion and forming device 4, a scraper 10, a water trough 5, a take-up unit 9, an extrusion wheel cooling control unit 11, and an extrusion rod cooling control unit 12. The feed rod 2 enters between the extrusion wheel 1 and the compacting wheel 3 and is fed by the extrusion wheel 1 into the expansion and forming device 4 for continuous extrusion to produce a large-diameter extruded rod 8. The extruded rod 8 is cooled in the water trough 5 and then wound onto the take-up unit. A suspended spray device 13 is provided on the left side of the water trough 5, with multiple spray devices 6 provided above and below.

[0036] The feeding order of the feed rod is short material first, then copper-magnesium alloy upper guide rod with low magnesium content (0.05-0.10%), and after it is well filled, high-strength (0.3-0.7%) copper-magnesium alloy upper guide rod is fed last.

[0037] The extrusion wheel 1 is cooled by the extrusion wheel cooling control device 11, and the suspended spray device 13 and the spray device 6 are controlled by the extrusion rod cooling control device 12. The extrusion wheel cooling control device 11 and the extrusion rod cooling control device 12 are independently arranged, which not only ensures a stable high-temperature production environment for the extrusion tooling, but also meets the requirement of rapid cooling of the extrusion rod.

[0038] A certain slope is set below the water tank 5 to help the cooling water after use to quickly enter the water outlet 7.

[0039] The suspended spraying device 13 can spray cooling water onto the extrusion die 46 to cool the copper rod immediately to prevent the grain size from increasing.

[0040] There is no dead angle between the spraying devices 6, and they have a certain range and spray diameter, so that the copper rod can be cooled evenly and quickly to room temperature.

[0041] The expansion molding device includes a cavity 43, a cavity cover 44 and a stop block 49. The cavity 43 and the cavity cover 44 are connected by bolts 48 to form a cavity inside. The leftmost side of the cavity is a feed port 41. The feed port 41 is connected to the cavity expansion area 42. The cavity expansion area 42 is connected to the mold 46 through a gasket 45. The gasket 45 is conical inside, and its large diameter side is connected to the cavity expansion area 42, and the diameter size is the same as the diameter at the connection with the expansion area 42. The small diameter side is connected to the mold 46, and the diameter size is larger than the mold hole size. The right side of the mold 46 is a discharge port 47.

[0042] The working plane of the blocking block 49 is higher than the lower plane of the feed port 41 , thereby increasing the filling space of the expansion area.

[0043] The feed port 41 is configured as an eccentric structure, which facilitates the filling of the high-strength copper alloy.

[0044] The cavity expansion area 42 includes three areas: the first area is the right-angle channel area A, which is an eccentric structure, the distance between the upper right-angle channel and the axis is a, and the distance between the lower right-angle channel and the axis is b, a>b, and the starting and ending positions of the upper and lower right-angle channels are not on the same vertical plane, which can make the flow rate of the material in the right-angle channel more uniform; the second area is the conical expansion area B, and the conical expansion area B is provided with two expansion angles, which can effectively promote the expansion forming of high-strength copper-magnesium alloy; the third area is the parallel expansion area C, and the parallel expansion area C is set with a certain inclination angle to facilitate demolding.

[0045] The stopper 49 , the gasket 45 and the mold 46 are all made of high-temperature alloy and have high resistance to high temperature, wear and impact.

[0046] The copper-magnesium alloy contact wire made of the above-mentioned large-diameter high-strength copper-magnesium alloy extruded rod can have a strength of more than 600 MPa and a conductivity greater than 65% IACS.

[0047] The workflow is as follows:

[0048] After starting the machine, first turn on the extrusion wheel cooling control device 11, feed the short material before extrusion, and then feed the copper-magnesium alloy upper guide rod with a low magnesium content. After it is well filled, finally feed the high-strength copper-magnesium alloy upper guide rod. Under the action of the compacting wheel 3, each feed rod 2 moves stably together with the extrusion wheel 1 groove. When the feed rod 2 encounters the blocking block 49, it changes direction and enters the expansion molding device 4 from the feed port 41. After the expansion molding is completed under the joint action of the cavity expansion area 42, the gasket 45 and the mold 46, the extrusion rod 8 enters the water tank 5 from the discharge port 47, and the extrusion rod cooling device 12 is turned on. The hanging spray device 13 and the spray device 6 are used to fully cool the extrusion rod 8. The cooled large-diameter extrusion rod 8 is wound on the take-up device 9, which arranges the wires at a uniform speed and has no traction on the large-diameter extrusion rod. After the extrusion is completed, the remaining material in the expansion molding device 4 is demolded and taken out, and the expansion molding device 4 is ready for use.

[0049] The process parameters are as follows:

[0050] Before extrusion, heat the expansion molding device to 550-650°C and hold it there for 60 minutes. Heat 5-10 short rods to 800-900°C. Prepare at least 20m of low-magnesium copper alloy upper guide rods, which are ductile and easily expandable, to raise the overall temperature of the extrusion tooling. Clean the surface of the high-strength copper-magnesium alloy upper guide rods, which have a magnesium content (mass fraction) of 0.3-0.7%, and set aside.

[0051] The pressing amount of the compacting wheel is controlled at 3-6mm. At this time, the forces between the feed rod, compacting wheel and extrusion wheel are balanced, and the feed rod is smoothly fed into the expansion forming device.

[0052] The clearance between the expansion molding device and the extrusion wheel is controlled at 0.4-1mm, which prevents wear between the tooling and avoids material waste.

[0053] The speed of the extrusion wheel is 1.8-5r / min. When feeding short materials, the speed is set to 1.8-2.8r / min. When running smoothly, the speed is set to 3-5r / min, which effectively prevents the quality defects of the extrusion rod caused by the speed of the extrusion wheel being too fast or too slow.

[0054] The extrusion wheel cooling system and the copper rod cooling system are set independently. The inlet temperature of the extrusion wheel cooling water is controlled at 15-30℃, and the inlet temperature of the copper rod cooling water is controlled at 10-20℃. The water flow rate is 0-6m³ / h.

[0055] The extrusion ratio range is 1.44-3.24.

[0056] Example:

[0057] Before extrusion, heat the expansion forming device 4 to 600°C and hold for 60 minutes. Heat eight short pieces of pure copper to 900°C and prepare a 25-meter copper-magnesium alloy upper guide rod with a magnesium content of 0.05-0.10% (mass fraction). Clean the surface of the high-strength copper-magnesium alloy upper guide rod with a magnesium content of 0.5-0.7% and set aside.

[0058] The downward pressure of the compacting wheel 3 is set to 3mm, the clearance between the expansion forming device 4 and the extrusion wheel 1 is controlled at 0.4mm, and the extrusion ratio is 2.31. The speed of the extrusion wheel 1 is approximately 2r / min when feeding short materials, and 3r / min during stable operation. The feeding order is first 8 heated short materials, then the copper-magnesium alloy upper guide rod with low magnesium content, and finally the high-strength copper-magnesium alloy upper guide rod. The water flow rate of the extrusion wheel cooling control device 11 is 4.5m³ / h, and the water inlet temperature is 15-25°C. The water flow rate of the extrusion rod cooling device 12 is 6m³ / h, and the water inlet temperature is 10-20°C.

[0059] In addition to the above embodiments, the present invention also includes other implementation methods. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the scope of protection of the claims of the present invention.

Claims

1. A method for continuously extruding large-diameter high-strength copper-magnesium alloy bars, characterized by: A device for continuously extruding large-diameter high-strength copper-magnesium alloy rods is used. The device comprises an extrusion wheel (1), a compaction wheel (3), an expansion forming device (4), a water trough (5), and a take-up device (9). A feed rod (2) enters between the extrusion wheel (1) and the compaction wheel (3), and is fed by the extrusion wheel (1) into the expansion forming device (4) for continuous extrusion to obtain a large-diameter extruded rod (8). The extruded rod (8) is cooled in the water trough (5) and then wound on the take-up device (9). The expansion molding device (4) includes a cavity (43) and a cavity cover (44), wherein a cavity is formed between the cavity (43) and the cavity cover (44), wherein a gasket (45) and a mold (46) are embedded in the cavity, wherein the left side of the gasket (45) is connected to the cavity expansion area (42), and the cavity expansion area (42) is connected to the leftmost feed port (41) of the cavity, wherein the gasket (45) is tapered inside, wherein the large diameter side thereof is connected to the cavity expansion area (42), and the diameter size is the same as the diameter at the connection point of the expansion area (42), and the small diameter side thereof is connected to the mold (46), and the diameter size is larger than the mold hole size, and the right side of the mold (46) is a discharge port (47); The cavity expansion area (42) is composed of a right-angle channel area A, a tapered expansion area B and a parallel expansion area C from left to right; The feed port (41) is configured as an eccentric structure, the right-angle channel area A is an eccentric structure, and the starting and ending positions of the upper and lower right-angle channels are not on the same vertical plane, the conical expansion area B is provided with two expansion angles, and the parallel expansion area C is provided with a certain inclination angle; The method comprises the following steps: Step 1: First, turn on the extrusion wheel cooling control device, feed the short material before extrusion, and then feed the copper-magnesium alloy upper guide rod with low magnesium content. After it is well filled, finally feed the high-strength copper-magnesium alloy upper guide rod; Step 2: Each feed rod moves stably together with the extrusion wheel under the action of the compacting wheel. When the feed rod encounters the blocking block, it changes direction and enters the expansion molding device from the feed port. After the expansion molding is completed under the joint action of the cavity expansion area, the gasket and the mold, the extrusion rod enters the water tank from the discharge port, the extrusion rod cooling device is turned on, and the hanging spray device and the spray device are used to fully cool the extrusion rod. The cooled large-diameter extrusion rod is wound on the take-up device. In step 1, before extrusion, the expansion forming device is heated to 550-650°C and kept warm for 60 minutes; 5-10 short rods are heated to 800-900°C, and at least 20m of copper-magnesium alloy upper guide rods with a magnesium content of 0.05-0.10% are prepared; after they are filled, high-strength copper-magnesium alloy upper guide rods with a magnesium content of 0.5-0.7% are fed.

2. The method for continuously extruding a large-diameter, high-strength copper-magnesium alloy bar according to claim 1, characterized in that: A material stop block (49) is provided on the left side of the cavity (43), and a working plane of the material stop block (49) is higher than the lower plane of the feed port (41).

3. The method for continuously extruding a large-diameter, high-strength copper-magnesium alloy bar according to claim 1, characterized in that: The water trough (5) is arranged at the discharge port of the expansion forming device (4), and the water trough (5) is provided with a hanging spray device (13) corresponding to the discharge port of the expansion forming device. The water trough (5) is provided with a plurality of spray devices (6) along the length direction of the extrusion rod (8).

4. The method for continuously extruding a large-diameter, high-strength copper-magnesium alloy bar according to claim 3, characterized in that: The extrusion wheel (1) is cooled by an extrusion wheel cooling control device (11), and the suspended spray device (13) and the spray device (6) are controlled by an extrusion rod cooling control device (12). The extrusion wheel cooling control device (11) and the extrusion rod cooling control device (12) are independently arranged.

5. The method for continuously extruding a large-diameter, high-strength copper-magnesium alloy bar according to claim 1, characterized in that: The pressing amount of the compacting wheel is controlled at 3-6 mm, the matching clearance between the expansion forming device and the extrusion wheel is controlled at 0.4-1 mm, the speed of the extrusion wheel is 1.8-5 r / min, and the extrusion ratio is 1.44-3.

24.

6. The method for continuously extruding a large-diameter, high-strength copper-magnesium alloy bar according to claim 5, characterized in that: The inlet temperature of the extrusion wheel cooling water is controlled at 15-30℃, and the inlet temperature of the copper rod cooling water is controlled at 10-20℃. Spray cooling is adopted, and the water flow rate of both is 0-6m³ / h.

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