One-step forming method for super-large copper-aluminum alloy busbar

Abstract

The invention discloses a one-time forming method for a super-large copper-aluminum alloy busbar, and relates to the technical field of copper-aluminum composite eutectic plate production, which has the steps of casting, rolling, heat treatment, etc. Compared with the prior art, the present application designs an aluminum alloy busbar with copper clad on both sides of the end, and through the end copper cladding technology, it has a copper-aluminum eutectic structure at both ends, which greatly improves the mechanical properties and oxidation resistance of the copper-aluminum composite busbar, and solves the problem that the current equipment cannot produce large-size copper-aluminum eutectic composite materials through a large roller one-time solid-liquid continuous casting and rolling forming technology. Due to the solid-liquid continuous casting and rolling one-time forming, there is no gap on the copper-aluminum bonding surface, which eliminates the possibility of electrochemical corrosion, the bonding surface peeling strength is high, the copper layer and the aluminum layer are not easy to separate, the performance is better, the reliability of the copper-aluminum eutectic busbar is improved, the connection performance of the busbar is also improved, and the conductive performance and mechanical properties are much better than the existing welded copper-aluminum composite busbar.

Description

Technical Field

[0001] The invention relates to the technical field of copper-aluminum composite eutectic plate production, and in particular to a one-time forming production technology for an ultra-long end double-sided copper-clad aluminum alloy busbar. Background Art

[0002] For large and extra-large transformers, generators or starters, the internal busbars need to be longer than 3 meters, but the existing casting and rolling process is limited by the size of the casting and rolling rollers, and can only directly produce busbars with a length of less than 1.75 meters. For extra-long busbars, two or more small-sized busbars can only be welded together for compounding. However, the busbar needs to pass a large current for a long time during use. Due to the material differences and welding quality at the weld, the composite busbar may break or crack after long-term use. Once this happens, it will bring serious safety hazards and immeasurable economic losses. At the same time, electromagnetic oxidation will occur at the weld and cause powder corrosion, resulting in increased resistance, which greatly reduces the capacity of the busbar and even makes it unusable.

[0003] For this purpose, the method of the present application adopts super-large casting and rolling equipment to form an ultra-long aluminum alloy busbar with copper clad on both sides of the ends in one step. The busbar formed in one step is better than the welded spliced ​​busbar and the cold-rolled extended busbar in terms of mechanical properties and electrical conductivity. Summary of the invention

[0004] The present invention aims at the deficiencies in the prior art and provides a one-time forming method for an ultra-large copper-aluminum alloy busbar. Through the end copper cladding technology, both ends of the busbar have a copper-aluminum eutectic structure, which greatly improves the mechanical properties and oxidation resistance of the copper-aluminum composite busbar and greatly reduces the amount of copper used. The one-time hot rolling forming technology with large rollers solves the problem that current equipment cannot produce large-size copper-aluminum eutectic composite materials. Since it is hot-rolled one-time forming, there is no gap on the copper-aluminum bonding surface, which eliminates the possibility of electrochemical corrosion. The bonding surface has high peeling strength, and the copper layer and aluminum layer are not easy to separate, which has better performance, improves the reliability of the copper-aluminum eutectic busbar, and improves the connection performance of the busbar. The conductivity and mechanical properties are much better than those of the existing welded copper-aluminum composite busbar.

[0005] In order to solve the above technical problems, the present invention is solved by the following technical solutions: A one-time forming method of an ultra-large copper-aluminum alloy busbar, comprising the following steps: Step A: adding raw aluminum ingots to a smelting furnace for smelting treatment, heating to 720°C to 750°C to obtain molten aluminum liquid, pouring the molten aluminum liquid into a holding furnace, controlling the temperature at 720°C to 740°C, and keeping it warm for 20 to 60 minutes; Step B: unwinding four copper strips on an unwinding machine respectively, two of which are wound on the upper roller of a twin-roll casting and rolling equipment, and the other two copper strips are wound on the lower roller of the twin-roll casting and rolling equipment On the upper roller and the lower roller, there is an adjustable limit device for limiting the winding position of the copper strip; Step C: After the aluminum liquid is kept still, it is degassed and filtered through online processing equipment such as a degassing box and a filter box; Step D: The distance between the copper strips on the same roller is the distance between the adjustable limit devices, and the aluminum liquid in the temperature range of 705℃ to 715℃ is injected into the gap between the upper and lower rollers under static pressure through the casting nozzle, and the injection width is the sum of the width of the copper strips on both sides of the rollers and the distance between them; Step E: The upper and lower rollers cool the molten aluminum liquid and the copper strip and solid-liquid cast and roll to form a copper-aluminum composite slab with copper on both sides of the end. Step F: The copper-aluminum composite slab coil is placed in an annealing furnace for homogenization annealing, the heating temperature is 350℃ to 450℃, and the annealing time is 15 to 30h; Step G: Then the copper-aluminum composite slab is introduced into the slitting equipment, and slitting is performed according to the product size to obtain the required size of the end double-sided copper-clad aluminum alloy busbar.

[0006] In the above technical solution, preferably, it also includes step H: straightening and leveling the aluminum alloy busbar with copper clad on both sides of the end, then chamfering it through a chamfering device, and straightening and leveling it again after the chamfering is completed.

[0007] In the above technical scheme, preferably, each uncoiler corresponds to an adjustable limit device relative to the X-axis direction of the rolling roller, the uncoiler and the corresponding adjustable limit device have a linkage mechanism, the uncoiler and the corresponding adjustable limit device are displaced relative to the Y-axis direction of the rolling roller, and when displaced, the uncoiler and the corresponding adjustable limit device move the same distance and direction.

[0008] In the above technical scheme, preferably, in step B, the adjustable limiting device is a limiting roller, and there are adjustable baffles on both sides of the limiting roller. The copper strip passes between the adjustable baffles, and then the copper strip is wound on the rolling roller in the opposite direction of the casting direction. At the same time, each copper strip is equipped with a tensioning roller and a pressure roller to ensure that the four copper strips move at the same speed and that the copper strips are tightly fitted with the rolling rollers after entering the hot rolling area.

[0009] In the above technical solution, preferably, in step B, a heating roller cooperating with the copper strip is provided on one side of the casting nozzle, and the heating roller heats the copper strip to between 100°C and 150°C.

[0010] In the above technical scheme, preferably, in step B, the adjustable limit device is a limit roller, and there are adjustable baffles on both sides of the limit roller. The copper strip passes between the adjustable baffles, and then the copper strip is wound on the roller in the same direction as the casting and rolling direction. At the same time, each copper strip is equipped with a clamping heating roller, which heats the copper strip to between 100°C and 150°C and allows the copper strip to fit tightly with the roller after entering the solid-liquid casting and rolling area.

[0011] In the above technical solution, preferably, in step E, the cooling rate is 300°C / s to 1000°C / s.

[0012] In the above technical solution, preferably, rolling and cooling are performed only in the solid-liquid casting and rolling area.

[0013] In the above technical solution, preferably, after the casting in step E, the copper-aluminum composite slab coil is cold rolled to a required thickness as required.

[0014] An ultra-large copper-aluminum alloy busbar is manufactured by a one-step forming method of an ultra-large copper-aluminum alloy busbar.

[0015] This application mainly produces copper-clad aluminum alloy busbars with a length of 3m or more. Compared with the existing technology, this application has two substantial characteristics. The first is the end copper-clad technology. Compared with the existing two-sided copper-clad busbars, this application greatly reduces the amount of copper used without reducing the conductivity of the same size. The second is the large-size production technology. Compared with the existing welded composite busbars, the busbars formed by one-time hot rolling in this application are far superior to welded composite busbars in terms of conductivity and mechanical properties.

[0016] The present application uses a twin-roll casting equipment with a roll width exceeding 3.2 m, preferably a roll width of 3.5 m.

[0017] To this end, the technical solution of this application overcomes many technical difficulties.

[0018] First, when copper is coated on both sides or one side, the casting nozzle only needs to statically inject the aluminum liquid onto the copper plate or between two copper plates, and the entire injection width is uniform. As long as the copper plate conveying speed, hot rolling speed and injection speed are constant, continuous hot rolling production can be achieved. However, the present application is completely different. The present application is copper coated on both sides of the end, that is, there is no copper plate in the middle, that is, aluminum liquid actually overflows from both ends during the aluminum liquid injection process. If the copper strip does not fit the roller tightly, especially the copper strip on the upper roller, the aluminum liquid will overflow onto the copper strip that has not entered the roller. At the same time, a total of four copper strips are required for the two end surfaces, and the speeds of these four copper strips must be consistent, otherwise as long as the speed of one copper strip is different, serious quality problems will occur. For this reason, the copper strip must be tightly fitted on the roller, leaving space for aluminum liquid and synchronizing the winding speeds of the four copper strips. For this reason, the present application requires an additional clamping roller to press the copper strip tightly against the roller.

[0019] Second: Since the width of the rolling roller exceeds 3.2m and the supporting uncoiler is not wide enough, each copper strip needs to be equipped with an uncoiler. There are a total of 4 copper strips on the upper and lower ends of this application, which require 4 uncoilers. Since the uncoilers are dispersed, the position of the copper strip from the uncoiler to the rolling roller is very important. Therefore, this application requires the copper strip to be positioned before it is wound onto the rolling roller. For this purpose, this application has an adjustable limit device. The adjustable limit device is generally a limit roller linked to the uncoiler. Limit stops are set on both sides of the limit roller. By adjusting the distance between the limit stops, copper strips of different widths can be accurately rolled onto the rolling roller. At the same time, in order to prevent deviation, the limit roller is consistent with the X-axis direction of the uncoiler, which can ensure that the copper strip has no inclination.

[0020] Third: The copper strip of the present application is a copper-aluminum eutectic busbar. When the rollers are hot-rolling the copper and aluminum, there is a cooling device inside the rollers, which can cool the copper-aluminum alloy. The benefit of cooling is that smaller grains can be formed and the material strength can be improved. If the temperature of copper is between 150°C and 220°C during the hot rolling of copper and aluminum, the copper atoms can obtain enough energy to migrate in a short time under high temperature conditions, forming a thicker copper-aluminum eutectic layer, thereby effectively improving the bonding strength of the copper-aluminum composite interface. However, it has been explained above that the copper strip needs to fit tightly on the rollers, and there is a cooling device inside the rollers. If the copper strip is preheated and then passes through the rollers, it will lose temperature before entering the hot rolling area. For this reason, the copper strip needs to be heated before entering the hot rolling area. The present application sets up two structures, one is how the copper strip is pressed and heated when entering the hot rolling area in the positive direction, and the other is how the copper strip is pressed and heated when entering the hot rolling area in the negative direction. Since the copper plates in the prior art are changed into copper strips, that is, there is a gap between the two copper strips, the influence of the copper strips on the casting nozzle and the blank is greatly reduced when they are brought in and out.

[0021] Fourthly, this application requires the improvement of the cooling system of the roller. The original roller cooling system is evenly distributed inside the roller, that is, the roller surface cooling rate is consistent, but this application requires the copper strip to be heated before hot rolling. This requires the improvement of the roller cooling system to maximize the cooling rate in the hot rolling area and reduce the cooling capacity in other areas, so as to keep the copper strip warm to the greatest extent.

[0022] Compared with the prior art, the present application designs an aluminum alloy busbar with copper clad on both sides of the ends. Through the copper cladding technology at the ends, it has a copper-aluminum eutectic structure at both ends, which greatly improves the mechanical properties and oxidation resistance of the copper-aluminum composite busbar and greatly reduces the amount of copper used. The large-scale roller one-time hot rolling forming technology solves the problem that the current equipment cannot produce large-size copper-aluminum eutectic composite materials. Due to the one-time hot rolling forming, there is no gap in the copper-aluminum bonding surface, which eliminates the possibility of electrochemical corrosion. The bonding surface has high peeling strength, and the copper layer and aluminum layer are not easy to separate, which has better performance, improves the reliability of the copper-aluminum eutectic busbar, and improves the connection performance of the busbar. The conductivity and mechanical properties are much better than the existing welded copper-aluminum composite busbar. DETAILED DESCRIPTION

[0023] The following is a clear and complete description of the technical solutions of the various embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments described in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1: Production of 3m long and 10mm thick end double-sided copper-clad aluminum alloy busbar, a single copper sheet is 20cm long and 1.5mm thick. A twin-roll casting equipment with a roll width of 3.5m is used.

[0025] The method comprises the following steps: Step A: adding a raw aluminum ingot into a smelting furnace for smelting treatment, heating the raw aluminum ingot to 720°C to 750°C to obtain molten aluminum liquid; pouring the molten aluminum liquid into a holding furnace, controlling the temperature at 720°C to 740°C, and keeping the temperature for 20 to 60 minutes; the raw aluminum ingot is an aluminum material of model 1G20, 1050, 1060, 1100, with an aluminum content greater than 99.2%, or is a high-strength and high-conductivity aluminum alloy ingot, and the high-strength and high-conductivity aluminum alloy ingot comprises, by weight percentage, 0.015% to 0.05% Ce, 0.015% to 0.05% La, 0.05% to 0.25% Si, 0.015% to 0.05% Zn, 0.025% to 0.10% Cu, 0.10% to 0.50% Fe, 0.015% to 0.035% Ti titanium, 0.015%~0.035% B boron, the rest is Al aluminum and unavoidable impurities. The thickness is 16mm.

[0026] Step B: Unwind four copper strips on the unwinder respectively, two of which are wound on the upper roller of the twin-roll casting and rolling equipment, and the other two are wound on the lower roller of the twin-roll casting and rolling equipment. There are adjustable limit devices next to the upper roller and the lower roller to limit the winding position of the copper strip. Each unwinder corresponds to an adjustable limit device relative to the X-axis direction of the roller. The unwinder and the corresponding adjustable limit device have a linkage mechanism. The unwinder and the corresponding adjustable limit device are displaced relative to the Y-axis direction of the roller, and when displaced, the unwinder and the corresponding adjustable limit device move the same distance and direction. The adjustable limit device is a limit roller, and there are adjustable baffles on both sides of the limit roller. The copper strip passes between the adjustable baffles to ensure that the unwinder, the limit roller and the copper strip are in a straight line. The copper strip is T2 copper or brass. Before unwinding, the copper strip is first rinsed with high pressure to quickly remove solid impurities on the surface of the copper plate, and then rinsed with low pressure. The rinse liquid is an alkaline degreasing liquid at 50°C for degreasing to remove grease on the surface of the copper plate. Finally, the oxide layer on the surface of the copper plate is polished away by a steel brush equipment. After polishing, the roughening degree of the copper strip surface can be improved, the copper-aluminum composite area can be increased, and the bonding ability of the composite material can be enhanced.

[0027] Step C: After the aluminum liquid is kept still, it is degassed and filtered through online processing equipment such as degassing boxes and filter boxes. The rolls in the twin-roll casting equipment have a cooling function. It is best that the rolls are cooled only in the hot rolling area, and not outside the hot rolling area, which is conducive to the insulation of the copper strip.

[0028] Step D: Four copper strips are wound on the upper rollers from the injection direction of the casting nozzle. At the same time, each copper strip is also equipped with a tensioning roller and a pressing roller. The speed of the copper strips is adjusted by the tensioning roller and the pressing roller to ensure that the speed of the four copper strips winding the rollers is consistent. At the same time, the pressing roller ensures that the copper strips are tightly attached to the rollers when entering the hot rolling area. There is also a heating roller on one side of the casting nozzle. Usually, one copper strip is equipped with a heating roller. The heating roller is close to the hot rolling area. The heating roller heats the copper strip to 150°C. The aluminum liquid in the temperature range of 710°C is injected into the gap between the upper and lower rollers through the casting nozzle. The injection width is the sum of the width of the copper strips on both sides of the rollers and the distance between them. Step E: The upper and lower rollers cool the molten aluminum liquid and copper strips and solid-liquid cast to form a copper-aluminum composite slab coil with copper on both sides of the end; at the same time, the upper and lower rollers cool the copper-aluminum composite slab. The cooling rate is 300°C / s. The coolant in the upper and lower rollers is water, and the water is kept at a temperature of 20°C in the upper and lower rollers. When the aluminum liquid is injected through the casting nozzle, it cools and solidifies rapidly after contacting the rollers. Similarly, when the aluminum liquid contacts the copper strip, it also cools rapidly. The aluminum liquid contacts the upper and lower copper strips in the casting and rolling area and crystallizes. The heat is taken out by the cooling water circulating in the rollers. After casting and rolling, the copper-aluminum composite slab is cold-rolled to the required thickness as needed.

[0029] Step F: Place the copper-aluminum composite plate blank into an annealing furnace for homogenization annealing, the heating temperature is 400°C, and the annealing time is 15 hours. Step G: Then introduce the copper-aluminum composite plate into the slitting equipment. Before slitting, it can be divided into blocks to reduce the difficulty of slitting. Slitting is performed according to the product size to obtain the copper-aluminum eutectic transition busbar of the required size. Step H: Straighten and level the copper-aluminum eutectic transition busbar, then chamfer it through the chamfering equipment, and straighten and level it again after the chamfering is completed.

[0030] Example 2: Production of 2.8m long and 8mm thick double-sided copper-clad aluminum busbar, a single copper sheet is 20cm long and 1.5mm thick. A twin-roll casting equipment with a roll width of 3.5m is used.

[0031] The method comprises the following steps: Step A: adding a raw aluminum ingot into a smelting furnace for smelting treatment, heating the raw aluminum ingot to 720°C to 750°C to obtain molten aluminum liquid; pouring the molten aluminum liquid into a holding furnace, controlling the temperature at 720°C to 740°C, and keeping the temperature for 20 to 60 minutes; the raw aluminum ingot is an aluminum material of model 1G20, 1050, 1060, 1100, with an aluminum content greater than 99.2%, or is a high-strength and high-conductivity aluminum alloy ingot, and the high-strength and high-conductivity aluminum alloy ingot comprises, by weight percentage, 0.015% to 0.05% Ce, 0.015% to 0.05% La, 0.05% to 0.25% Si, 0.015% to 0.05% Zn, 0.025% to 0.10% Cu, 0.10% to 0.50% Fe, 0.015% to 0.035% Ti titanium, 0.015%~0.035% B boron, the rest is Al aluminum and unavoidable impurities. The thickness is 16mm.

[0032] Step B: Unwind four copper strips on the unwinder respectively, two of which are wound on the upper roller of the twin-roll casting and rolling equipment, and the other two are wound on the lower roller of the twin-roll casting and rolling equipment. There are adjustable limit devices next to the upper roller and the lower roller to limit the winding position of the copper strip. Each unwinder corresponds to an adjustable limit device relative to the X-axis direction of the roller. The unwinder and the corresponding adjustable limit device have a linkage mechanism. The unwinder and the corresponding adjustable limit device are displaced relative to the Y-axis direction of the roller, and when displaced, the unwinder and the corresponding adjustable limit device move the same distance and direction. The adjustable limit device is a limit roller, and there are adjustable baffles on both sides of the limit roller. The copper strip passes between the adjustable baffles to ensure that the unwinder, the limit roller and the copper strip are in a straight line. The copper strip is T2 copper or brass. Before unwinding, the copper strip is first rinsed with high pressure to quickly remove solid impurities on the surface of the copper plate, and then rinsed with low pressure. The rinse liquid is an alkaline degreasing liquid at 50°C for degreasing to remove grease on the surface of the copper plate. Finally, the oxide layer on the surface of the copper plate is polished away by a steel brush equipment. After polishing, the roughening degree of the copper strip surface can be improved, the copper-aluminum composite area can be increased, and the bonding ability of the composite material can be enhanced.

[0033] Step C: After the aluminum liquid is kept still, it is degassed and filtered through online processing equipment such as degassing boxes and filter boxes. The rolls in the twin-roll casting equipment have a cooling function. It is best that the rolls are cooled only in the hot rolling area, and not outside the hot rolling area, which is conducive to the insulation of the copper strip.

[0034] Step D: Four copper strips are respectively wound on the upper rollers in the same direction from the injection direction of the casting nozzle. Each copper strip is equipped with a pressing and heating roller. The pressing and heating roller heats the copper strip to 150°C and allows the copper strip to fit tightly with the roller after entering the hot rolling area, while ensuring that the four copper strips are wound on the rollers at the same speed. The aluminum liquid in the temperature range of 710°C is injected into the gap between the upper and lower rollers through the casting nozzle. The injection width is the sum of the width of the copper strips on both sides of the rollers and the distance between them; Step E: The upper and lower rollers cool the molten aluminum liquid and copper strips and solid-liquid cast and roll to form a copper-aluminum composite slab coil with copper on both sides of the end; At the same time, the upper and lower rollers cool the copper-aluminum composite slab. The cooling rate is 300°C / s. The coolant in the upper and lower rollers is water, and the water is kept at a temperature of 20°C in the upper and lower rollers. When the aluminum liquid is injected through the casting nozzle, it cools and solidifies rapidly after contacting the rollers. Similarly, when the aluminum liquid contacts the copper strip, it also cools rapidly. The aluminum liquid contacts the upper and lower copper strips in the casting and rolling area and crystallizes. The heat is taken out by the cooling water circulating in the rollers. After casting and rolling, the copper-aluminum composite slab is cold-rolled to the required thickness as needed.

[0035] Step F: Place the copper-aluminum composite plate blank into an annealing furnace for homogenization annealing, the heating temperature is 400°C, and the annealing time is 15 hours. Step G: Then introduce the copper-aluminum composite plate into the slitting equipment. Before slitting, it can be divided into blocks to reduce the difficulty of slitting. Slitting is performed according to the product size to obtain the copper-aluminum eutectic transition busbar of the required size. Step H: Straighten and level the copper-aluminum eutectic transition busbar, then chamfer it through the chamfering equipment, and straighten and level it again after the chamfering is completed.

[0036] Example 3: Production of 3.2m long and 6mm thick double-sided copper-clad aluminum busbar, a single copper sheet is 20cm long and 1mm thick. A twin-roll casting equipment with a roll width of 3.5m is used.

[0037] The method comprises the following steps: Step A: adding a raw aluminum ingot into a smelting furnace for smelting treatment, heating the raw aluminum ingot to 720°C to 750°C to obtain molten aluminum liquid; pouring the molten aluminum liquid into a holding furnace, controlling the temperature at 720°C to 740°C, and keeping the temperature for 20 to 60 minutes; the raw aluminum ingot is an aluminum material of model 1G20, 1050, 1060, 1100, with an aluminum content greater than 99.2%, or is a high-strength and high-conductivity aluminum alloy ingot, and the high-strength and high-conductivity aluminum alloy ingot comprises, by weight percentage, 0.015% to 0.05% Ce, 0.015% to 0.05% La, 0.05% to 0.25% Si, 0.015% to 0.05% Zn, 0.025% to 0.10% Cu, 0.10% to 0.50% Fe, 0.015% to 0.035% Ti titanium, 0.015%~0.035% B boron, the rest is Al aluminum and unavoidable impurities. The thickness is 16mm.

[0038] Step B: Unwind four copper strips on the unwinder respectively, two of which are wound on the upper roller of the twin-roll casting and rolling equipment, and the other two are wound on the lower roller of the twin-roll casting and rolling equipment. There are adjustable limit devices next to the upper roller and the lower roller to limit the winding position of the copper strip. Each unwinder corresponds to an adjustable limit device relative to the X-axis direction of the roller. The unwinder and the corresponding adjustable limit device have a linkage mechanism. The unwinder and the corresponding adjustable limit device are displaced relative to the Y-axis direction of the roller, and when displaced, the unwinder and the corresponding adjustable limit device move the same distance and direction. The adjustable limit device is a limit roller, and there are adjustable baffles on both sides of the limit roller. The copper strip passes between the adjustable baffles to ensure that the unwinder, the limit roller and the copper strip are in a straight line. The copper strip is T2 copper or brass. Before unwinding, the copper strip is first rinsed with high pressure to quickly remove solid impurities on the surface of the copper plate, and then rinsed with low pressure. The rinse liquid is an alkaline degreasing liquid at 50°C for degreasing to remove grease on the surface of the copper plate. Finally, the oxide layer on the surface of the copper plate is polished away by a steel brush equipment. After polishing, the roughening degree of the copper strip surface can be improved, the copper-aluminum composite area can be increased, and the bonding ability of the composite material can be enhanced.

[0039] Step C: After the aluminum liquid is kept still, it is degassed and filtered through online processing equipment such as degassing boxes and filter boxes. The rolls in the twin-roll casting equipment have a cooling function. It is best that the rolls are cooled only in the hot rolling area, and not outside the hot rolling area, which is conducive to the insulation of the copper strip.

[0040] Step D: Two of the four copper strips covering the aluminum alloy are respectively wound on rollers in opposite directions from the injection direction of the casting nozzle. At the same time, both copper strips are equipped with tensioning rollers and pressing rollers. The speed of the copper strips is adjusted by the tensioning rollers and the pressing rollers. At the same time, the pressing rollers ensure that the copper strips are tightly fitted on the rollers when entering the hot rolling area. There is also a heating roller on one side of the casting nozzle. Usually, one copper strip is equipped with a heating roller. The heating roller is close to the hot rolling area and heats the copper strip to 150°C. The other two copper strips covering the bottom of the aluminum alloy are respectively wound on rollers in the same direction from the injection direction of the casting nozzle. Each copper strip is equipped with a pressing heating roller. The pressing heating roller heats the copper strip to 150°C and allows the copper strip to fit tightly with the roller after entering the hot rolling area. At the same time, the speed of the four copper strips winding the rollers is ensured to be consistent. The aluminum liquid in the temperature range of 710℃ is injected into the gap between the upper and lower rollers through the casting nozzle, and the injection width is the sum of the width of the copper strips on both sides of the rollers and the distance between them; Step E: The upper and lower rollers cool the molten aluminum liquid and the copper strip and solid-liquid cast and roll to form a copper-aluminum composite slab coil with copper on both sides of the end; At the same time, the upper and lower rollers cool the copper-aluminum composite slab. The cooling rate is 300℃ / s. The coolant in the upper and lower rollers is water, and the water is kept at a temperature of 20℃ in the upper and lower rollers. When the aluminum liquid is injected through the casting nozzle, the aluminum liquid contacts the rollers and cools and solidifies rapidly. Similarly, the aluminum liquid contacts the copper strips and cools rapidly. The aluminum liquid contacts and crystallizes with the upper and lower copper strips in the casting and rolling area, and the heat is taken out by the cooling water circulating in the rollers. After casting and rolling, the copper-aluminum composite slab coil is cold rolled to the required thickness as needed.

[0041] Step F: Place the copper-aluminum composite plate blank into an annealing furnace for homogenization annealing, the heating temperature is 400°C, and the annealing time is 15 hours. Step G: Then introduce the copper-aluminum composite plate into the slitting equipment. Before slitting, it can be divided into blocks to reduce the difficulty of slitting. Slitting is performed according to the product size to obtain the copper-aluminum eutectic transition busbar of the required size. Step H: Straighten and level the copper-aluminum eutectic transition busbar, then chamfer it through the chamfering equipment, and straighten and level it again after the chamfering is completed.

[0042] In Examples 1 to 3, when the substrate is a high-strength and high-conductivity aluminum alloy, the tensile strength is ≥150MPa and the elongation is about 14.0% at 25°C and 68% humidity. The conductivity is ≥60.6%IACS at 20°C and the resistance is less than 0.0283Ω·mm 2 / m.

Claims

1. A one-step forming method for an ultra-large copper-aluminum alloy busbar, characterized in that: The twin-roll casting equipment with a roll width of more than 3.2m includes the following steps: Step A: adding raw aluminum ingots into a smelting furnace for smelting to obtain molten aluminum liquid; Step B: four copper strips are unwound on unwinding machines respectively, two of which are closely attached to the upper rolls of the twin-roll casting and rolling equipment, and the other two are closely attached to the lower rolls of the twin-roll casting and rolling equipment, and adjustable limit devices are provided beside the upper rolls and the lower rolls for limiting the winding positions of the copper strips; each unwinding machine corresponds to an adjustable limit device in the X-axis direction of the roll, and the unwinding machine and the corresponding adjustable limit device have a linkage mechanism, and the unwinding machine and the corresponding adjustable limit device are displaced in the Y-axis direction of the roll, and when displaced, the unwinding machine and the corresponding adjustable limit device move the same distance and in the same direction; Step C: After being kept warm and allowed to stand, the aluminum liquid is degassed and filtered through online processing equipment such as a degassing box and a filter box; Step D: The distance between the copper strips on the same roller is the distance between the adjustable limit devices, and the aluminum liquid in the temperature range of 705℃~715℃ is injected into the gap between the upper and lower rollers under static pressure through the casting nozzle. The injection width is the sum of the width of the copper strips on both sides of the roller and the distance between them. The gap between the upper and lower rollers is the solid-liquid casting area; Step E: The upper and lower rollers cool the molten aluminum and copper strip and perform solid-liquid casting to form a copper-aluminum composite slab coil with copper clad on both sides of the ends; Step F: placing the copper-aluminum composite sheet blank coil into an annealing furnace for homogenization annealing at a heating temperature of 350° C. to 450° C. for an annealing time of 15 h to 30 h; Step G: The copper-aluminum composite slab is then introduced into a slitting device, and slitting is performed according to the product size to obtain a double-sided copper-clad aluminum alloy busbar of a required size.

2. The one-step forming method of a super-large copper-aluminum alloy busbar according to claim 1 is characterized by: The step also includes step H: straightening and leveling the aluminum alloy busbar with copper clad on both sides of the end, then chamfering it with a chamfering device, and straightening and leveling it again after the chamfering is completed.

3. According to the one-time forming method of a super-large copper-aluminum alloy busbar as described in claim 1, it is characterized in that, in step B, the adjustable limiting device is a limiting roller, and there are adjustable baffles on both sides of the limiting roller. The copper strip passes between the adjustable baffles, and then the copper strip is wound on the roller in the opposite direction of the casting and rolling direction. At the same time, each copper strip is equipped with a tensioning roller and a pressure roller to ensure that the movement speed of the four copper strips is consistent and the copper strips are tightly fitted with the rollers after entering the hot rolling area.

4. The one-step forming method of a super-large copper-aluminum alloy busbar according to claim 3 is characterized in that: In step B, a heating roller cooperating with the copper strip is provided on one side of the casting nozzle, and the heating roller heats the copper strip to between 100°C and 150°C.

5. According to claim 1, a one-time forming method for a super-large copper-aluminum alloy busbar is characterized in that, in step B, the adjustable limiting device is a limiting roller, and there are adjustable baffles on both sides of the limiting roller. The copper strip passes between the adjustable baffles, and then the copper strip is wound on the roller in the same direction as the casting and rolling direction. At the same time, each copper strip is equipped with a clamping heating roller, which heats the copper strip to between 100°C and 150°C and allows the copper strip to fit tightly with the roller after entering the solid-liquid casting and rolling area.

6. The one-step forming method of a super-large copper-aluminum alloy busbar according to claim 1 is characterized by: In step A, the aluminum liquid is heated to 720° C. to 750° C. to obtain molten aluminum.

7. The one-step forming method of a super-large copper-aluminum alloy busbar according to claim 1 is characterized by: After the casting in step F, the copper-aluminum composite slab coil is cold rolled to a desired thickness as required.

8. The one-step forming method of a super-large copper-aluminum alloy busbar according to claim 1 is characterized by: In step B, the aluminum liquid is kept warm in a holding furnace at a temperature of 720° C. to 740° C., and then allowed to stand for 20 min to 60 min.

9. The one-step forming method of a super-large copper-aluminum alloy busbar according to claim 1, characterized in that, in step F, the annealing temperature is 350°C to 450°C, and the annealing time is 15 h to 30 h.

10. An ultra-large copper-aluminum alloy busbar, characterized by: The super-large copper-aluminum alloy busbar is manufactured by a one-step forming method according to any one of claims 1 to 9.