Equipment and method for continuously extruding large-diameter high-strength copper-magnesium alloy barTechnical Field
The invention relates to the technical field of metal extrusion molding, in particular to equipment and a method for continuously extruding a large-diameter high-strength copper-magnesium alloy bar.
Background
The existing copper and copper alloy contact wires can be divided into pure copper, copper-silver alloy, copper-tin alloy and copper-magnesium alloy according to the materials, and are suitable for electric locomotives with the highest operation speed of 350Km/h and below, and the processing technology is generally up-draw continuous casting, continuous extrusion and drawing molding. With the progress of technology, research on high-speed railways at home and abroad is gradually deepened, and the running speed of high-speed trains is higher and higher. In order for a high speed train to run smoothly at higher speeds, a high strength contact line must be used. In recent years, the research of high-strength contact wires by students is mainly focused on copper-chromium-zirconium contact wires, but the high-strength contact wires still have a plurality of problems in aspects of large length guiding, stable performance and the like, the tensile strength of the existing copper-magnesium alloy contact wires is lower, the higher-speed operation of an electric locomotive cannot be met, and the research on the aspect of developing the high-strength copper-magnesium alloy contact wires is not carried out in the industry, so that the invention provides an expansion forming process and a tooling die for continuously extruding large-diameter high-strength copper-magnesium alloy bars, and the expansion forming process and the tooling die are used for producing the high-strength copper-magnesium alloy contact wires.
Chinese patent CN208680200U discloses a combined die cavity for continuous extrusion molding of large diameter bar, comprising a cavity and a cavity cover, wherein the cavity and the cavity cover are respectively provided with a feed inlet and a discharge outlet, a die cavity is enclosed between the cavity and the cavity cover, an extrusion die is fixedly embedded in the die cavity, a bearing is molded in the extrusion die, a horn cavity is arranged on one side of the extrusion die, a plastic blocking block is tightly arranged in the horn cavity, a molding pad is embedded in the die cavity, a diversion trench is molded in the molding pad, the molding pad comprises a first molding pad and a second molding pad, and the diversion trench comprises a first diversion trench and a second diversion trench.
Chinese patent CN203253761U discloses an expansion molding device for continuously extruding a copper bar with a large cross section, comprising a cavity, wherein the cavity comprises a cavity panel and a cover plate, the cavity panel is fixedly connected with the cover plate, an expansion cavity is formed in the joint of the cavity panel and the cover plate, and a gasket and a die are sequentially installed in the expansion cavity.
The technical scheme is that the expansion molding device developed for aluminum and aluminum alloy, copper and copper alloy materials with good plasticity and easy expansion is not suitable for high-strength copper-magnesium alloy materials with high strength, poor plasticity and difficult filling, so that the invention aims at the problems that the high-strength copper-magnesium alloy materials with poor plasticity and difficult expansion are not filled, the extrusion rod is split, lack of materials, the extruder load is large and the like frequently occur in continuous extrusion.
Disclosure of Invention
The invention aims to overcome the defects, and provides equipment and a method for continuously extruding large-diameter high-strength copper-magnesium alloy bars, which are used for realizing continuous extrusion of large-diameter high-strength copper-magnesium alloy extrusion bars by lengthening the length of an expansion area of a cavity, optimizing a right-angle channel structure and increasing a secondary expansion angle, solving the problems of unfilled extrusion bar split, material shortage, large extrusion bar load, difficult demoulding and the like when extruding the large-diameter copper-magnesium alloy extrusion bars, and realizing continuous production of the extrusion bars for high-strength copper-magnesium alloy contact wires with magnesium content of 0.3-0.7% and specification of 30-45mm diameter.
The purpose of the invention is realized in the following way:
The equipment for continuously extruding large-diameter high-strength copper-magnesium alloy bar comprises an extrusion wheel, a compaction wheel, an expansion forming device, a water tank and a wire collecting device, wherein a feeding rod enters between the extrusion wheel and the compaction wheel, is fed into the expansion forming device by the extrusion wheel to be continuously extruded to obtain a large-diameter extrusion rod, and is cooled by the water tank and then is wound on the wire collecting device.
Preferably, the expansion forming device comprises a cavity and a cavity cover, a cavity is formed between the cavity and the cavity cover, a gasket and a die are embedded in the cavity, the left side of the gasket is connected with a cavity expansion area, the cavity expansion area is connected with a feeding hole on the leftmost side of the cavity, the inside of the gasket is conical, the large-diameter side of the gasket is connected with the cavity expansion area, the diameter of the part, which is connected with the expansion area, of the gasket is the same, the small-diameter side of the gasket is connected with the die, the diameter of the small-diameter side of the gasket is larger than the size of the die hole, and the right side of the die is a discharging hole.
Preferably, a baffle block is arranged on the left side of the cavity, and the working plane of the baffle block is higher than the lower plane of the feed inlet.
Preferably, the cavity expansion area is a right-angle channel area A, a conical expansion area B and a parallel expansion area C in sequence from left to right.
Preferably, the water tank is arranged at a discharge hole of the expansion molding device, a suspension type spraying device is arranged at the discharge hole of the water tank corresponding to the expansion molding device, and a plurality of spraying devices are arranged along the length direction of the extrusion rod.
Preferably, the extrusion wheel is cooled by an extrusion wheel cooling control device, the suspension 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 arranged.
A method for continuously extruding a large-diameter high-strength copper-magnesium alloy bar adopts the equipment, and comprises the following steps:
Firstly, opening a cooling control device of an extrusion wheel, feeding short materials before extrusion, then feeding copper-magnesium alloy upper guide rods with lower magnesium content, and finally feeding high-strength copper-magnesium alloy upper guide rods after the copper-magnesium alloy upper guide rods are well filled;
Step two, each feed rod and extrusion wheel steady motion together under the effect of compaction wheel, after the feed rod runs into the fender material piece and changes the direction and get into expansion forming device by the feed inlet, accomplish the expansion shaping under cavity expansion area, packing ring and mould's combined action after, the extrusion rod gets into the basin from the discharge gate, opens extrusion rod cooling device, hangs spray set and fully cools off the extrusion rod, and the major diameter extrusion rod after the cooling is convoluteed on take-up.
Preferably, in the first step, the expansion molding device is heated to 550-650 ℃ before extrusion, the temperature is kept for 60min, 5-10 short material rods are heated to 800-900 ℃, copper-magnesium alloy upper guide rods with the magnesium content of 0.05-0.10% are prepared for at least 20m, and after the copper-magnesium alloy upper guide rods are filled, high-strength copper-magnesium alloy upper guide rods with the magnesium content of 0.5-0.7% are fed.
Preferably, the pressing amount of the compacting wheel is controlled to be 3-6mm, the fit clearance between the expansion forming device and the extruding wheel is controlled to be 0.4-1mm, the rotating speed of the extruding wheel is 1.8-5r/min, and the extruding ratio is 1.44-3.24.
Preferably, the water inlet temperature of the cooling water of the extrusion wheel is controlled to be 15-30 ℃, the water inlet temperature of the cooling water of the copper rod is controlled to be 10-20 ℃, and a spray cooling mode is adopted, wherein the water flow speed of the cooling water of the extrusion wheel and the copper rod is 0-6m3/h.
The beneficial effects of the invention are as follows:
(1) Continuous extrusion of the large-diameter high-strength copper-magnesium alloy extrusion rod is realized;
(2) The extrusion wheel cooling control device and the extrusion rod cooling device are independently arranged, so that the extrusion tool is convenient to adjust, the stable high-temperature production environment of the extrusion tool is ensured, the copper rod can be effectively cooled, and the growth of crystal grains in the copper rod is prevented;
(3) After the heating short material is fed before the high-strength copper-magnesium alloy upper guide rod is connected, the copper-magnesium alloy upper guide rod with good plasticity and low magnesium content which is easy to expand is used for filling the cavity, so that on one hand, the extrusion tooling can be heated in a short time to form a stable temperature field, the plastic expansion of the high-strength copper-magnesium alloy upper guide rod is promoted, and on the other hand, when the high-strength copper-magnesium alloy upper guide rod is extruded, the copper-magnesium alloy with low magnesium content filled in the cavity plays a good role in blocking, so that the high-strength copper-magnesium alloy material is fully filled in the cavity;
(4) The extrusion stroke is increased by lengthening the extension area of the cavity, so that the problem that high-strength copper-magnesium alloy is difficult to fill is solved, the integrity of the cavity is ensured, and the bearing capacity and the service life of the cavity are increased;
(5) The right-angle channel areas in the feeding port and the cavity expansion area are of eccentric structures, and the starting and stopping positions of the upper right-angle channel and the lower right-angle channel are not on the same vertical plane, so that the phenomenon of unbalanced stress of the copper-magnesium alloy material in the right-angle channel is avoided, the difference value between the upper flow velocity and the lower flow velocity is reduced, and the quality of the extrusion rod is improved;
(6) The second area of the cavity expansion area is internally provided with two expansion angles, so that the high-strength copper-magnesium alloy with poor plasticity is easier to fill;
(7) The third area of the cavity expansion area is provided with a certain inclination angle in parallel with the expansion area, so that demolding is facilitated;
(8) The working plane of the baffle block is higher than the lower plane of the feed inlet, and the filling space of the expansion area is increased;
(9) The copper-magnesium alloy contact line strength produced by continuous extrusion of the large-diameter high-strength copper-magnesium alloy extrusion rod produced by the invention can reach more than 600MPa, and the conductivity reaches more than 72 percent IACS.
Drawings
Fig. 1 is a schematic structural view of the present invention.
Fig. 2 is a partial enlarged view of fig. 1.
Fig. 3 is a schematic structural view of the expansion molding device.
FIG. 4 is a schematic structural view of a cavity expansion region.
The device comprises a squeezing wheel 1, a feeding rod 2, a compacting wheel 3, an expansion forming device 4, a water tank 5, a spraying device 6, a water outlet 7, a squeezing rod 8, a wire collecting device 9, a scraper 10, a squeezing wheel cooling control device 11, a squeezing rod cooling control device 12, a suspension spraying device 13, a feeding hole 41, a cavity expansion area 42, a cavity 43, a cavity cover 44, a gasket 45, a mold 46, a discharge hole 47, bolts 48 and a baffle block 49.
Detailed Description
Referring to fig. 1-4, the invention relates to equipment for continuously extruding large-diameter high-strength copper-magnesium alloy bars, which comprises an extrusion wheel 1, a feeding rod 2, a compacting wheel 3, an expansion forming device 4, a scraper 10, a water tank 5, a wire winding machine 9, an extrusion wheel cooling control device 11 and an extrusion rod cooling control device 12. The feeding rod 2 enters between the extrusion wheel 1 and the compaction wheel 3, is sent into the expansion molding device 4 by the extrusion wheel 1 to be continuously extruded to obtain an extrusion rod 8 with a large diameter, and the extrusion rod 8 is coiled on the wire winding device after being cooled by the water tank 5. The left side of the water tank 5 is provided with a suspension type spray device 13, and a plurality of spray devices 6 are respectively arranged at the upper part and the lower part.
The feeding sequence of the feeding rod is that firstly short materials are fed, then the copper-magnesium alloy upper guide rod with low magnesium content (0.05-0.10%) is fed, and after the copper-magnesium alloy upper guide rod is well filled, the copper-magnesium alloy upper guide rod with high strength (0.3-0.7%) is fed.
The extrusion wheel 1 is cooled by the extrusion wheel cooling control device 11, the suspension type spray device 13 and the spray device 6 are controlled by the extrusion rod cooling control device 12, and the extrusion wheel cooling control device 11 and the extrusion rod cooling control device 12 are independently arranged, so that stable high-temperature production environment of the extrusion tool is ensured, and the requirement of rapid cooling of the extrusion rod is met.
A certain inclination is arranged below the water tank 5, so that the cooling water after use can quickly enter the water outlet 7.
The suspension type spraying device 13 can spray cooling water to the extrusion die 46, and the copper rod is cooled at the first time to avoid the increase of the grain size.
The spraying devices 6 have no dead angle, have a certain range and spraying diameter, and can uniformly and rapidly cool the copper rod to room temperature.
The expansion molding device comprises a cavity 43, a cavity cover 44 and a baffle block 49, wherein the cavity 43 and the cavity cover 44 are connected through bolts 48, a cavity is formed inside, the leftmost side of the cavity is a feed inlet 41, the feed inlet 41 is connected with a cavity expansion area 42, the cavity expansion area 42 is connected with a die 46 through a gasket 45, the inside of the gasket 45 is conical, the large-diameter side of the gasket is connected with the cavity expansion area 42, the diameter of the joint between the diameter size and the expansion area 42 is the same, the small-diameter side of the gasket is connected with the die 46, the diameter size of the joint is larger than the size of a die hole, and the right side of the die 46 is provided with a discharge hole 47.
The working plane of the baffle block 49 is higher than the lower plane of the feed inlet 41, and the filling space of the expansion area is increased.
The feed port 41 is provided in an eccentric configuration to facilitate the filling of the high strength copper alloy.
The cavity expansion area 42 comprises three areas, wherein a first area is a right-angle channel area A, the right-angle channel area A is of an eccentric structure, the distance between an upper right-angle channel and an axis is a, the distance between a lower right-angle channel and the axis is B, a > B, the starting and stopping positions of the upper right-angle channel and the lower right-angle channel are not on the same vertical plane, so that the flow velocity of materials in the right-angle channel is more uniform, a second area is a conical expansion area B, two expansion angles are arranged in the conical expansion area B, expansion molding of high-strength copper magnesium alloy can be effectively promoted, and a third area is a parallel expansion area C, and a certain inclination angle is arranged in the parallel expansion area C, so that demolding is facilitated.
The material blocking 49, the gasket 45 and the die 46 are all made of high-temperature alloy, and have high-temperature resistance, wear resistance and impact resistance.
The contact line strength of the copper-magnesium alloy manufactured by the large-diameter high-strength copper-magnesium alloy extrusion rod can reach more than 600MPa, and the conductivity is more than 65% IACS.
The working procedure is as follows:
After the machine is started, the extrusion wheel cooling control device 11 is firstly opened, short materials are fed before extrusion, then copper-magnesium alloy upper guide rods with lower magnesium content are fed, after the copper-magnesium alloy upper guide rods are well filled, finally high-strength copper-magnesium alloy upper guide rods are fed, all feed rods 2 move together with the extrusion wheel 1 groove stably under the action of the compacting wheel 3, when the feed rods 2 meet the baffle blocks 49, the direction of the feed rods is changed, the feed rods enter the expansion forming device 4 through the feed inlets 41, after expansion forming is completed under the combined action of the cavity expansion area 42, the gasket 45 and the die 46, the extrusion rods 8 enter the water tank 5 from the discharge outlets 47, the extrusion rod cooling device 12 is opened, and the extrusion rods 8 are fully cooled by the hanging spraying devices 13 and the spraying devices 6. The cooled large-diameter extrusion rod 8 is wound on a wire winding device 9, and the wire winding device 9 is uniformly arranged and has no traction force on the large-diameter extrusion rod. And after extrusion, demolding and taking out the residual materials in the expansion molding device 4, and reserving the expansion molding device 4.
The process parameters are as follows:
Heating the expansion molding device to 550-650 ℃ before extrusion, preserving heat for 60min, heating 5-10 short material rods to 800-900 ℃, preparing a low-magnesium copper alloy upper guide rod with good plasticity and easy expansion for at least 20m for improving the integral temperature of an extrusion tool, and removing dust and impurities on the surface of the high-strength copper-magnesium alloy upper guide rod for later use. The magnesium content (mass fraction) of the high-strength copper-magnesium alloy upper guide rod is 0.3-0.7%.
The pressing amount of the compacting wheel is controlled to be 3-6mm, the stress among the feeding rod, the compacting wheel and the extruding wheel is balanced, and the feeding rod stably enters the expansion forming device.
The fit clearance between the expansion forming device and the extrusion wheel is controlled to be 0.4-1mm, so that the abrasion between the tools is prevented, and the waste of materials is avoided.
The rotating speed of the extrusion wheel is 1.8-5r/min, the rotating speed is set to be 1.8-2.8r/min when short materials are fed, and the rotating speed is set to be 3-5r/min when the extrusion wheel is in stable operation, so that the quality defect of the extrusion rod caused by too high or too low rotating speed of the extrusion wheel is effectively prevented.
The extrusion wheel cooling system and the copper rod cooling system are independently arranged, the water inlet temperature of the extrusion wheel cooling water is controlled to be 15-30 ℃, the water inlet temperature of the copper rod cooling water is controlled to be 10-20 ℃, and the water flow rates are all 0-6m < 3 >/h.
The extrusion ratio ranges from 1.44 to 3.24.
Examples:
heating the expansion molding device 4 to 600 ℃ before extrusion, preserving heat for 60min, heating 8 pure copper short materials to 900 ℃, and preparing a copper-magnesium alloy upper guide rod 25m with the magnesium content of 0.05-0.10% (mass fraction). The surface of the high-strength copper-magnesium alloy upper guide rod with the magnesium content of 0.5-0.7% is dedusted and decontaminated for standby.
The pressing quantity of the compacting wheel 3 is set to be 3mm, the fit clearance between the expansion forming device 4 and the pressing wheel 1 is controlled to be 0.4mm, the extrusion ratio is 2.31, the rotating speed of the pressing wheel 1 is about 2r/min when short materials are fed, and the rotating speed is 3r/min when the machine runs stably. The feeding sequence is that 8 heated short materials are firstly arranged, then a copper-magnesium alloy upper guide rod with lower magnesium content is arranged, and finally a high-strength copper-magnesium alloy upper guide rod is arranged, the water flow rate of the extrusion wheel cooling control device 11 is 4.5m3/h, and the water inlet temperature is 15-25 ℃. The water flow rate of the extrusion rod cooling device 12 is 6m3/h, and the water inlet temperature is 10-20 ℃.
In addition to the above embodiments, the present invention also includes other embodiments, and all technical solutions that are formed by equivalent transformation or equivalent substitution should fall within the protection scope of the claims of the present invention.