Red copper bar and production method thereof

Abstract

The invention relates to the technical field of non-ferrous metal calendaring, in particular to a red copper bar and a production method thereof, the number of annealing twin crystals / the number of crystal grains on the unit area (mm < 2 >) of the red copper bar is less than 500ppm, and the sub-grain structure is more than 60%. In order to solve the problems in the prior art, the number of annealing twin crystals / the number of crystal grains on the unit area (mm < 2 >) of the red copper bar is controlled to be smaller than 500 ppm, the sub-grain structure is controlled to be larger than 60%, a fine grain structure with the grain size smaller than 25 microns is obtained, the product structure is more compact, the surface is finer, the repulsive force to impurities is higher, and high-temperature blistering of the product is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous metal rolling processing, in particular to a copper busbar and a production method thereof. Background Art

[0002] Red copper is a metal primarily composed of copper. Due to its extremely low impurity content, it appears reddish or purple in color. It has excellent electrical and thermal conductivity and ductility, and is widely used in electrical, electronic, and heat exchange fields. Red copper busbars are processed copper plates or strips, often used in power transmission, busbar manufacturing, and electronic equipment, and possess excellent electrical conductivity and mechanical strength.

[0003] In the prior art, there are many technical solutions for copper smelting.

[0004] For example, Chinese patent CN202410136429.7 discloses a method for preparing a C-type copper busbar, comprising: the preparation method comprising: S1: smelting; S2: upward continuous casting; S3, continuous extrusion; S4, drawing; the continuous extrusion in S3 uses an extrusion tool, the extrusion tool comprising: an extrusion die, the extrusion die having an extrusion cavity, the extrusion cavity comprising: a bottom cavity and two side cavities, the two side cavities being respectively arranged at the two ends of the bottom cavity, the two side cavities being located on the same side of the bottom cavity, the two side cavities being symmetrically arranged at the two ends of the bottom cavity, the bottom cavity being arranged horizontally, the side cavities being arranged obliquely, and the bottom cavity and the side cavities forming an angle, the angle being 55° to 80°. With the extrusion tool having a special structure, the preparation of the copper busbar is simple, the prepared copper busbar is dimensionally stable, has small fluctuations, has a high yield rate, can be produced stably, and the service life of the extrusion die is increased.

[0005] For another example, Chinese patent CN202010372831.7 discloses a method for producing special-shaped copper busbars, the process flow of which is upward continuous casting → oxygen-free copper rod → extrusion → drawing → straightening → inspection. The cold working rate of the extruded copper rod in the drawing process is 5-35%; the straightening process is to first saw the copper busbar drawn by the cold drawing machine, with a sawing length of 1-5 meters, and then straighten the sawn copper busbar with a straightening machine, with a straightening stroke of 20mm-120mm. Due to the adoption of the above technical solution, the problem of poor straightness in the production process of special-shaped copper busbars is solved. The special-shaped copper busbar products produced by this method have high straightness and good assemblability, reducing or eliminating assembly difficulties and problems such as short product service life due to poor assembly; improving product qualification rate and reducing production costs.

[0006] However, during the actual implementation process, the inventors found that copper profiles usually need to be extruded to have a specific shape. However, when used to make small-sized copper busbars, the extrusion process will cause the smaller material to have a more obvious temperature rise, thereby inducing the carbonization of internal impurities and moving them to the edge of the material. When subsequently used in high-temperature scenarios, the carbonized interlayer will cause bubbles on the surface of the copper busbar, resulting in bulging of the copper busbar surface. Summary of the Invention

[0007] In view of the above problems existing in the prior art, a copper busbar is provided;

[0008] On the other hand, a production method for producing the red copper busbar is also provided.

[0009] The specific technical solutions are as follows:

[0010] A copper busbar, wherein the copper busbar has a unit area (mm 2 )'s annealing twin number / grain number <500ppm, subgrain structure >60%.

[0011] On the other hand, the copper element mass percentage of the copper busbar is ≥99.95%, and the oxygen element content of the copper busbar is ≤10ppm.

[0012] On the other hand, the copper row is along <111> and <110> The proportion of extruded fibrous tissue in the processing direction is less than 10%.

[0013] A method for producing a copper busbar, used for producing the above-mentioned copper busbar;

[0014] The production method comprises: extruding a copper casting blank to obtain a copper profile, and then grinding the surface of the copper profile to remove surface impurities of the copper profile;

[0015] The copper profile is used to make the red copper busbar.

[0016] On the other hand, during the extrusion molding process, a continuous extruder is used with an extrusion die having an inlet taper of 45-60° and a sizing length of 1-3 mm to extrude the copper casting blank;

[0017] The specifications of the copper busbar are within the range of thickness*width (1-30)*(1-30)mm.

[0018] On the other hand, during the extrusion process, the extrusion current of the continuous extruder is between 400A and 480A;

[0019] The rotation speed of the continuous extruder is between 3.5 and 4.0 rpm;

[0020] The extrusion speed is between 10mm / min and 30mm / min.

[0021] On the other hand, before the extrusion molding, a drawing molding process is also included, and the drawing molding process includes:

[0022] Adding a drawing rod blank to the crystallizer;

[0023] injecting electrolytic copper into the crystallizer and passing circulating water into the crystallizer for cooling;

[0024] After the electrolytic copper is joined to the drawing rod blank, the preliminary drawing begins;

[0025] When the electrolytic copper begins to form an oxide layer, a mixture of nitrogen and carbon monoxide is added to the crystallizer through a bottom blowing device;

[0026] During the drawing and forming process, the drawing temperature is between 1150°C and 1200°C;

[0027] The pulling speed is between 300mm / min and 360mm / min;

[0028] The temperature difference between the water-cooling inlet and outlet temperatures of the crystallizer is between 10°C and 25°C.

[0029] On the other hand, 30 minutes after the start of the primary pulling, it is considered that the electrolytic copper has started to form an oxide layer.

[0030] On the other hand, before the drawing and forming process, a smelting process is also included, and the smelting process includes:

[0031] Pour the copper raw materials into the power frequency melting furnace for electrolytic melting, and then transfer them into the holding furnace for insulation;

[0032] During the electrolytic smelting process, the electrolytic plates of the power frequency smelting furnace are covered with charcoal for insulation;

[0033] The industrial frequency melting furnace is a 5T melting furnace;

[0034] The thickness of the charcoal covering is between 60mm and 100mm;

[0035] The holding furnace is covered with graphite flakes;

[0036] Covering thickness is greater than 10mm;

[0037] The holding temperature of the holding furnace is between 1100° C. and 1180° C.

[0038] On the other hand, gradient grinding is used in the grinding process;

[0039] The target grinding mesh is above 400 mesh;

[0040] The thickness of single-side grinding is between 0.05mm and 0.5mm;

[0041] The grinding speed is between 1 and 40 mm / min.

[0042] The above technical solution has the following advantages or beneficial effects:

[0043] In response to the problems in the prior art, the present invention controls the number of annealed twins / grains per unit area (mm2) of the copper busbar to <500ppm and the subgrain structure to >60%, thereby obtaining a fine-grained structure with a grain size of <25μm. The product structure is denser, the surface is finer, the repulsion of impurities is stronger, and high-temperature blistering of the product is avoided.

[0044] In order to address the problem that the copper busbar extrusion molding process in the existing technology is prone to carbonization of internal impurities and thus high-temperature blistering, this solution introduces a step of grinding the copper busbar surface after extrusion molding to remove the areas where interlayers are expected to form, thereby avoiding the problem of surface blistering in the copper busbar product during actual application.

[0045] By adding a surface grinding process, the surface roughness of the copper busbar is improved, bubbling on the product surface is avoided, and the safe and efficient application of copper busbar products in new energy vehicle battery pack radiators, energy storage equipment, electrical cabinet high-voltage switches and other fields can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The embodiments of the present invention will be described more fully with reference to the accompanying drawings, which are provided for illustration and description only and are not intended to limit the scope of the present invention.

[0047] Figure 1 is an overall schematic diagram of an embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of step S2 in an embodiment of the present invention;

[0049] Figure 3A This is a side view of the extrusion die in an embodiment of the present invention;

[0050] Figure 3B This is a front view of the extrusion die in an embodiment of the present invention;

[0051] Figure 4 Schematic diagram of step A3 in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0053] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other.

[0054] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0055] The present invention comprises:

[0056] A copper busbar, wherein the copper mass percentage of the copper busbar is ≥99.95%, the oxygen mass percentage of the copper busbar is ≤10ppm, and the area per unit area of the copper busbar (mm 2 ) annealing twin number / grain number <500ppm, sub-grain structure >60%, along <111> and <110> The proportion of extruded fibrous tissue in the processing direction is less than 10%.

[0057] By using the above parameters, a fine-grained structure with a grain size of less than 25 μm can be obtained, the product structure is denser, the surface is finer, and the repulsion of impurities is stronger.

[0058] If you follow <111> and <110> The proportion of extruded fibrous tissue in the processing direction is higher than 10%, the tissue is severely fibrotic, the density is low, and it is easy to produce blistering under high temperature conditions.

[0059] A method for producing a copper busbar, such as Figure 1 As shown, the complete production method includes:

[0060] Step S1: smelting the copper raw material to obtain molten electrolytic copper;

[0061] Step S2: drawing and forming the electrolytic copper into a copper casting blank;

[0062] During step S2, when the electrolytic copper begins to form an oxide layer, a mixture of nitrogen and carbon monoxide is blown into the copper;

[0063] Step S3: Extruding the copper casting blank to obtain a copper profile;

[0064] Step S4: Grinding the copper profile to obtain a finished copper busbar.

[0065] During step S4 , the grinding thickness is controlled to remove the portion of the copper profile where the interlayer is to be formed.

[0066] Specifically, to address the problem of carbonization of internal impurities and subsequent high-temperature blistering during the prior art copper busbar extrusion molding process, this embodiment studies the flow process in the material during the extrusion process for copper busbar products of specific specifications. This determines the movement mechanism of the impurity portion of the copper busbar of this specification during the extrusion process, and then predicts the approximate location where carbonized organic impurities will appear at the edge of the mold cavity. Based on this location, the copper profile is ground to remove the interlayer caused by impurities. When subsequently applied in high-temperature scenarios, since the organic impurities in the copper busbar interlayer are eliminated, there is no source of vaporization at high temperatures, and the bubble problem can be greatly improved.

[0067] Furthermore, in order to address the problem in the prior art that oxygen is easily introduced during the copper smelting process, leading to copper oxidation and a decrease in purity, in this solution, during the process of drawing and forming the electrolytic copper, when the electrolytic copper begins to form an oxide layer, a mixture of nitrogen and carbon monoxide is introduced to wrap the surface of the electrolytic copper, thereby reducing the contact between oxygen and copper. At the same time, a reduction reaction is carried out through carbon monoxide to remove the oxidized part, thereby effectively improving the purity of the finished copper busbar and helping to achieve better electrical conductivity.

[0068] In one embodiment, step S1 corresponding to the smelting process includes:

[0069] Pour the copper raw materials into the power frequency melting furnace for electrolytic melting, and then transfer them into the holding furnace for insulation;

[0070] During the electrolytic smelting process, the electrolytic plates of the power frequency smelting furnace are covered with charcoal for insulation.

[0071] Specifically, in order to achieve a better smelting process, in this embodiment, a combined smelting device consisting of a power frequency smelting furnace, a holding furnace and a crystallizer is used.

[0072] Among them, an electrolytic plate is placed in the power frequency smelting furnace to perform arc smelting on the copper raw material or copper concentrate to obtain copper liquid and remove impurities;

[0073] Subsequently, the molten copper is transferred to a holding furnace for insulation to prevent cooling and solidification.

[0074] The molten copper is then transferred from the holding furnace to a crystallizer. A water jacket is provided outside the crystallizer, and circulating water is passed into the water jacket for cooling, allowing the molten copper to crystallize and solidify.

[0075] In the above process, the molten copper is directed to move along the casting mold area of the crystallizer by pulling, thereby pulling out copper profiles of specific shapes.

[0076] In order to achieve better heating uniformity and avoid oxidation reaction when copper is heated, the electrolytic plates of the power frequency melting furnace are covered with charcoal to keep them warm and absorb oxygen before electrolytic smelting.

[0077] In one embodiment, the industrial frequency melting furnace is a 5T melting furnace;

[0078] The thickness of the charcoal covering is between 60mm and 100mm.

[0079] Specifically, in order to achieve a better smelting effect, in this embodiment, a 5T industrial frequency smelting furnace is selected for smelting, and the thickness of the charcoal covering is controlled between 60mm and 100mm to achieve a better covering and oxygen absorption effect.

[0080] In one embodiment, the holding furnace is covered with graphite flakes;

[0081] Covering thickness is greater than 10mm;

[0082] The holding temperature of the holding furnace is between 1100℃ and 1180℃.

[0083] Specifically, in order to avoid oxidation problems of electrolytic copper, in this embodiment, when the electrolytic copper in the copper liquid state is transferred to the holding furnace, the upper part of the holding furnace is covered with graphite flakes with a covering thickness greater than 10 mm, thereby achieving complete wrapping of the liquid surface and preventing oxidation caused by contact between the copper liquid and oxygen.

[0084] At the same time, graphite flakes have a large surface area. When the holding temperature of the holding furnace is controlled between 1100℃ and 1180℃, they can better absorb oxygen through oxidation reaction to avoid oxidation of electrolytic copper.

[0085] In one embodiment, Figure 2 As shown, step S2 corresponding to the pulling process includes:

[0086] Step S21: before drawing and forming, adding a drawing rod blank into the crystallizer;

[0087] Step S22: feeding the electrolytic copper into the crystallizer and cooling the crystallizer with circulating water;

[0088] Step S23: After the electrolytic copper is joined to the drawing rod blank, the initial drawing begins;

[0089] Step S24: When the electrolytic copper begins to form an oxide layer, a mixed gas is added to the crystallizer through the bottom blowing device.

[0090] Specifically, before starting smelting, a draw rod blank is pre-placed at the outlet of the crystallizer. In a preferred embodiment, the draw rod blank has a diameter of 25 mm.

[0091] When the molten copper enters the crystallizer for cooling, it will engage with the drawing rod blank. At this time, the copper casting blank can be drawn and formed by the drawing rod blank.

[0092] During the pulling process, when an oxide layer appears, mixed gas is added to the crystallizer through the bottom blowing device.

[0093] Among them, the bottom blowing device is arranged at the bottom of the crystallizer, which can blow mixed gas into the crystallizer for protection.

[0094] Specifically, the mixed gas includes nitrogen and carbon monoxide, wherein nitrogen is used as the main component to wrap the outside of the electrolytic copper to reduce the contact with oxygen;

[0095] At the same time, the oxygen content of electrolytic copper can be determined through relevant processes, and carbon monoxide in a corresponding proportion can be mixed in according to the oxygen content for reduction.

[0096] In addition, controlling the holding pressure of the bottom blowing gas between 20MPa and 25MPa can achieve better removal of the oxygen part.

[0097] In one embodiment, in step S24 , after 30 minutes of pulling, it is considered that the electrolytic copper has begun to form an oxide layer.

[0098] Specifically, in order to achieve a simpler process control flow, in this embodiment, after analyzing and calibrating the overall pulling process, it is generally believed that in the absence of mixed gas protection, after 30 minutes of pulling, the electrolytic copper is considered to have begun to form an oxide layer, and the oxide layer is in a stable state. At this time, the oxidized part can be better removed by blowing in mixed gas for protection.

[0099] In one embodiment, during the pulling process of step S2, the pulling temperature is between 1150° C. and 1200° C.;

[0100] The pulling speed is between 300mm / min and 360mm / min;

[0101] The temperature difference between the water-cooling inlet and outlet of the crystallizer is between 10℃ and 25℃.

[0102] Specifically, in order to achieve a better crystallization effect of electrolytic copper, in this embodiment, a relatively uniform pulling process is first achieved by controlling the pulling temperature between 1150°C and 1200°C and the pulling speed between 300mm / min and 360mm / min, and the rate of cooling crystallization is controlled by controlling the temperature difference between the water-cooled inlet and outlet water of the crystallizer between 10°C and 25°C. By controlling this rate, the grains in the crystallization process are relatively uniform and have fewer lattice defects, which is convenient for subsequent extrusion molding.

[0103] In one embodiment, step S3 corresponding to the extrusion process includes:

[0104] A continuous extruder is used to extrude the copper casting blank to obtain a copper profile;

[0105] During the extrusion process, the extrusion current is between 400A and 480A;

[0106] The speed of the continuous extruder is between 3.5 and 4.0 rpm;

[0107] The extrusion speed is between 10mm / min and 30mm / min.

[0108] Specifically, in order to achieve a better extrusion molding effect, in this embodiment, a continuous extruder is selected to extrude the copper casting, and during the extrusion molding process, the extrusion current is controlled to be between 400A and 480A, the rotation speed of the continuous extruder is controlled to be between 3.5 and 4.0rpm, and the extrusion speed is controlled to be between 10mm / min and 30mm / min, so that the copper busbar finally extruded has a smaller grain size, such as less than 30um, thereby making the surface of the copper busbar dense.

[0109] In one embodiment, in order to achieve a better extrusion effect on the copper casting embryo, a continuous extruder is also used in combination with the following Figure 3A The copper casting blank is extruded by an extrusion die with an inlet taper A101 between 45 and 60 degrees and a fixed diameter A102 length between 1 and 3 mm.

[0110] Specifically, when used to produce small-sized copper busbars, such as 7.5*15mm copper busbars, a larger extrusion force can be achieved by controlling the specifications of the copper busbars and adjusting the corresponding mold shape.

[0111] As the extrusion pressure increases, the density of the copper material will increase significantly, thereby increasing the bonding strength between the material atoms, reducing bubbles, and allowing impurities to flow to the edge of the mold cavity.

[0112] Due to the reduction of bubbles, it is less likely for bubbles to expand under high temperature conditions, thereby causing bubbling on the copper busbar surface.

[0113] At the same time, by controlling the specifications of the copper busbar, the raw materials are fully stirred and mixed after being squeezed into the mold cavity, so that the organic impurities in them are partially expelled to the edge of the mold cavity, making it easier to remove them through subsequent grinding.

[0114] In one embodiment, Figure 4 As shown, after executing step S3 and before executing step S4, the following steps are further included:

[0115] Step A3: Perform tolerance testing on the copper profile, and proceed to step S4 if the tolerance test passes.

[0116] Specifically, in order to achieve a better extrusion effect, in this embodiment, after completing a cycle of extrusion, the copper profile is first subjected to a tolerance test. When the tolerance test passes, step S4 is entered. If the tolerance is too large, it indicates that there is a problem with the extrusion die. The extrusion die needs to be adjusted, the spacing between the various components of the die needs to be changed, etc., and then extrusion is performed again.

[0117] In one embodiment, in step S4, the copper profile is surface-grinded to obtain the copper bar, and gradient grinding is used during the grinding process;

[0118] The target grinding mesh is above 400 mesh, which has a better mirror effect, strengthens the heat distribution, and weakens the problem of blistering caused by local overheating.

[0119] The thickness of single-side grinding is between 0.05mm and 0.5mm;

[0120] The grinding speed is between 1 and 40 mm / min. If the speed is too low, the grinding strength will be insufficient; if the grinding speed is too high, the surface consistency control will be poor.

[0121] Specifically, in order to achieve better flatness on the surface of the copper busbar, in this embodiment, grinding is further performed after extrusion molding, and gradient grinding is performed using a surface grinding device during the grinding process.

[0122] The grinding process using gradient grinding includes:

[0123] 1) First, grind the workpiece with a particle size of 100-200 mesh;

[0124] 2) Grinding the workpiece with a particle size of 200-500 mesh;

[0125] 3) Finally, the workpiece is ground using a grinding wheel with a particle size of 300-600 mesh.

[0126] Gradient polishing can achieve a superior mirror finish. First, a rough polish is used to remove the surface oxide layer. Then, two fine polishes are performed to remove the oxide and slag inclusion clusters present in the subsurface pressure layer. These measures eliminate blistering caused by foreign matter and repair the rough surface of the ground surface, resulting in a consistent mirror finish and enhanced resistance to thermal radiation, effectively alleviating localized blistering.

[0127] Based on the above production process, the following embodiments can be implemented, specifically including:

[0128] Example 1:

[0129] A copper busbar with a specification of 5.5*15.5, the specific production process is as follows:

[0130] First, place an electrolytic plate in the melting area of a 5t power frequency melting furnace and cover it with charcoal with a thickness of 60mm to 100mm.

[0131] At the same time, the inner wall of the insulation furnace is covered with graphite flakes;

[0132] The covering thickness of graphite flakes is more than 10mm;

[0133] Also, the input end of the crystallizer is connected to the output end of the holding furnace, circulating water is introduced into the water channel of the crystallizer, and a drawing rod blank with a diameter of φ25mm is set at the outlet of the crystallizer.

[0134] Then the smelting process begins, first the copper raw materials are melted to form electrolytic copper;

[0135] Then, the electrolytic copper is kept warm in a holding furnace at 1120°C, and the liquid surface needs to be covered to avoid oxidation.

[0136] Then, when the electrolytic copper flows into the crystallizer and joins with the rod blank, the drawing process begins;

[0137] The drawing temperature is 1160℃, the speed is 320mm / min, and the temperature difference between the water inlet and outlet is 20℃;

[0138] After 30 minutes of pulling, the bottom blowing device is turned on to blow in nitrogen with a pressure of 22 MPa. At the same time, carbon monoxide is mixed in according to the oxygen content requirements to form a mixed gas to protect the electrolytic copper.

[0139] The copper casting blank formed by drawing is extruded by using a TCJ400 continuous extruder to obtain copper profiles.

[0140] The extruder setting parameters include: extrusion current 485A, spindle speed 4.0rpm, extrusion speed 27mm / min;

[0141] It should be noted that since the front end of the copper profile is connected to the guide rod, the guide rod needs to be ground more than 0.6mm on one side before entering the extruder;

[0142] For the copper profiles output by the extruder, they are first cleaned with an alcohol mixture and then blown dry with a high-pressure air knife;

[0143] Then the product rows are cut to the required length and the dimensions of the product rows are measured to determine whether the dimensions meet the tolerances required by the process.

[0144] If it is out of tolerance, a new extrusion die needs to be replaced.

[0145] The removed mold needs to be polished before it can be used again.

[0146] If the tolerance meets the requirements, the surface of the product row is ground using surface grinding equipment to form a copper row;

[0147] The grinding mesh is above 400 mesh, the thickness of single-side grinding is 0.1mm, and the grinding speed is 18mm / min;

[0148] Finally, the product is packaged and shipped.

[0149] The copper busbar produced using this method has a conductivity of 101% IACAS and an oxygen content below 2 ppm. It can withstand 950°C for 18 hours without blistering. The material has a grain size of 30 μm, a tensile strength of 216 MPa, an elongation of 37%, and a roughness of 0.4 μm. The structure is uniform, the material exhibits excellent machinability, a subgrain ratio of 70%, and a twin / total grain count of 450 ppm.

[0150] Example 2:

[0151] A copper busbar with a specification of 7.5*13.5, the specific production process is as follows:

[0152] First, place an electrolytic plate in the melting area of a 5t power frequency melting furnace and cover it with charcoal with a thickness of 60mm to 100mm.

[0153] At the same time, the inner wall of the insulation furnace is covered with graphite flakes;

[0154] The covering thickness of graphite flakes is more than 10mm;

[0155] Also, the input end of the crystallizer is connected to the output end of the holding furnace, circulating water is introduced into the water channel of the crystallizer, and a drawing rod blank with a diameter of φ25mm is set at the outlet of the crystallizer.

[0156] Then the smelting process begins, first the copper raw materials are melted to form electrolytic copper;

[0157] Then, the electrolytic copper is kept warm in a holding furnace at 1120°C, and the liquid surface needs to be covered to avoid oxidation.

[0158] Then, when the electrolytic copper flows into the crystallizer and joins with the rod blank, the drawing process begins;

[0159] The drawing temperature is 1160℃, the speed is 320mm / min, and the temperature difference between the water inlet and outlet is 20℃;

[0160] After 30 minutes of pulling, the bottom blowing device is turned on to blow in nitrogen with a pressure of 22 MPa. At the same time, carbon monoxide is mixed in according to the oxygen content requirements to form a mixed gas to protect the electrolytic copper.

[0161] The copper casting blank formed by drawing is extruded by using a TCJ400 continuous extruder to obtain copper profiles.

[0162] The extruder setting parameters include: extrusion current 480A, spindle speed 3.95rpm, extrusion speed 26mm / min;

[0163] It should be noted that since the front end of the copper profile is connected to the guide rod, the guide rod needs to be ground more than 1.0mm on one side before entering the extruder;

[0164] For the copper profiles output by the extruder, they are first cleaned with an alcohol mixture and then blown dry with a high-pressure air knife;

[0165] Then the product rows are cut to the required length and the dimensions of the product rows are measured to determine whether the dimensions meet the tolerances required by the process.

[0166] If it is out of tolerance, a new extrusion die needs to be replaced.

[0167] The removed mold needs to be polished before it can be used again.

[0168] If the tolerance meets the requirements, the surface of the product row is ground using surface grinding equipment to form a copper row;

[0169] The grinding mesh is above 400 mesh, the thickness of single-side grinding is 0.4mm, and the grinding speed is 38mm / min;

[0170] Finally, the product is packaged and shipped.

[0171] The copper busbar produced according to the above method has a conductivity of 101.5% IACAS, an oxygen content of 2 ppm, and no blistering when kept at a high temperature of 950°C for 18 hours. The grain size of the material can be 20 μm, the tensile strength is 226 MPa, the elongation is 38%, the roughness is 0.6 μm, the subgrain ratio is 80%, and the number of twins / total grains is 400 ppm.

[0172] Comparative Example 1:

[0173] A copper busbar with a specification of 5.5*15.5, the specific production process is as follows:

[0174] First, place an electrolytic plate in the melting area of a 5t power frequency melting furnace and cover it with charcoal with a thickness of 60mm to 100mm.

[0175] At the same time, the inner wall of the insulation furnace is covered with graphite flakes;

[0176] The covering thickness of graphite flakes is more than 10mm;

[0177] Also, the input end of the crystallizer is connected to the output end of the holding furnace, circulating water is introduced into the water channel of the crystallizer, and a drawing rod blank with a diameter of φ25mm is set at the outlet of the crystallizer.

[0178] Then the smelting process begins, first the copper raw materials are melted to form electrolytic copper;

[0179] Then, the electrolytic copper is kept warm in a holding furnace at 1120°C, and the liquid surface needs to be covered to avoid oxidation.

[0180] Then, when the electrolytic copper flows into the crystallizer and joins with the rod blank, the drawing process begins;

[0181] The drawing temperature is 1160℃, the speed is 320mm / min, and the temperature difference between the water inlet and outlet is 20℃;

[0182] After 30 minutes of pulling, the bottom blowing device is turned on to blow in nitrogen with a pressure of 22 MPa. At the same time, carbon monoxide is mixed in according to the oxygen content requirements to form a mixed gas to protect the electrolytic copper.

[0183] The copper casting blank formed by drawing is extruded by using a TCJ400 continuous extruder to obtain copper profiles.

[0184] The extruder setting parameters include: extrusion current 455A, spindle speed 3.8rpm, extrusion speed 15mm / min;

[0185] For the copper profiles output by the extruder, they are first cleaned with an alcohol mixture and then blown dry with a high-pressure air knife;

[0186] Then the product rows are cut to the required length and the dimensions of the product rows are measured to determine whether the dimensions meet the tolerances required by the process.

[0187] If it is out of tolerance, a new extrusion die needs to be replaced.

[0188] The removed mold needs to be polished before it can be used again.

[0189] If the tolerances meet the requirements, the products are packaged and shipped.

[0190] The copper busbar produced according to the above method has a conductivity of 101% IACAS, an oxygen content of 15 ppm, and a lot of bubbles when the material is kept at a high temperature of 950°C for 18 hours. The grain size of the material is 45 μm, the tensile strength is 226 MPa, the elongation is 38%, the roughness is 1.9 μm, the subgrain ratio is 15%, and the number of twins / total grains is 21,000 ppm.

[0191] Comparative Example 2:

[0192] A copper busbar with a specification of 7.5*15.5, the specific production process is as follows:

[0193] First, place an electrolytic plate in the melting area of a 5t power frequency melting furnace and cover it with charcoal with a thickness of 60mm to 100mm.

[0194] At the same time, the inner wall of the insulation furnace is covered with graphite flakes;

[0195] The covering thickness of graphite flakes is more than 10mm;

[0196] Also, the input end of the crystallizer is connected to the output end of the holding furnace, circulating water is introduced into the water channel of the crystallizer, and a drawing rod blank with a diameter of φ25mm is set at the outlet of the crystallizer.

[0197] Then the smelting process begins, first the copper raw materials are melted to form electrolytic copper;

[0198] Then, the electrolytic copper is kept warm in a holding furnace at a temperature of 1100°C to 1180°C, and the liquid surface needs to be covered to prevent oxidation;

[0199] Then, when the electrolytic copper flows into the crystallizer and joins with the rod blank, the drawing process begins;

[0200] The drawing temperature is 1180℃, the speed is 350mm / min, and the temperature difference between the water inlet and outlet is 22℃;

[0201] The copper casting blank formed by drawing is extruded by using a TCJ400 continuous extruder to obtain copper profiles.

[0202] The extruder setting parameters include: extrusion current 445A, spindle speed 3.6rpm, extrusion speed 18mm / min;

[0203] For the copper profiles output by the extruder, they are first cleaned with an alcohol mixture and then blown dry with a high-pressure air knife;

[0204] Then the product rows are cut to the required length and the dimensions of the product rows are measured to determine whether the dimensions meet the tolerances required by the process.

[0205] If it is out of tolerance, a new extrusion die needs to be replaced.

[0206] The removed mold needs to be polished before it can be used again.

[0207] If the tolerances meet the requirements, the products are packaged and shipped.

[0208] The copper busbar produced according to the above method has a conductivity of 102% IACAS, an oxygen content of 15 ppm, and severe blistering when the material is kept at a high temperature of 950°C for 18 hours. The grain size of the material can be 55 μm, the tensile strength is above 206 MPa, the elongation is above 35%, the roughness is 1.8 μm, the subgrain ratio is 10%, and the number of twins / total grains is 20,000 ppm.

[0209] Table 1 Oxygen content and microstructure of examples and comparative examples

[0210]

[0211] In Table 1, <111> and <110> Direction of extruded fibrous tissue test method: using electron microscope, 500× field of view, orientation marking function statistics.

[0212] In Table 1, the subgrain ratio (%) and the number of twins / total grains were measured using a metallographic microscope with a 200× field of view.

[0213] Table 2 Performance results of the embodiments and comparative examples

[0214]

[0215] The above are only preferred embodiments of the present invention and do not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A copper busbar, characterized in that: The copper bar per unit area (mm 2 )'s annealing twin number / grain number <500ppm, subgrain structure >60%.

2. The copper busbar according to claim 1, characterized in that: The copper element mass percentage of the copper busbar is ≥99.95%, and the oxygen element content of the copper busbar is ≤10ppm.

3. The copper busbar according to claim 1, characterized in that: The copper row is along <111> and <110> The proportion of extruded fibrous tissue in the processing direction is less than 10%.

4. A method for producing a copper busbar, characterized in that: Used to produce the copper busbar as described in claims 1-3; The production method comprises: extruding a copper casting blank to obtain a copper profile, and then grinding the surface of the copper profile to remove surface impurities of the copper profile; The copper profile is used to make the red copper busbar.

5. The production method according to claim 4, characterized in that During the extrusion molding process, a continuous extruder is used with an extrusion die having an inlet taper of 45-60° and a sizing length of 1-3 mm to extrude the copper casting blank; The specifications of the copper busbar are within the range of thickness*width (1-30)*(1-30)mm.

6. The production method according to claim 4, characterized in that During the extrusion process, the extrusion current of the continuous extruder is between 400A and 480A; The rotation speed of the continuous extruder is between 3.5 and 4.0 rpm; The extrusion speed is between 10mm / min and 30mm / min.

7. The production method according to claim 4, characterized in that Before extrusion molding, a drawing molding process is also included, and the drawing molding process includes: Adding a drawing rod blank to the crystallizer; injecting electrolytic copper into the crystallizer and passing circulating water into the crystallizer for cooling; After the electrolytic copper is joined to the drawing rod blank, the preliminary drawing begins; When the electrolytic copper begins to form an oxide layer, a mixture of nitrogen and carbon monoxide is added to the crystallizer through a bottom blowing device; During the drawing and forming process, the drawing temperature is between 1150°C and 1200°C; The pulling speed is between 300mm / min and 360mm / min; The temperature difference between the water-cooling inlet and outlet temperatures of the crystallizer is between 10°C and 25°C.

8. The production method according to claim 7, characterized in that 30 minutes after the start of the initial pulling, it was considered that the electrolytic copper had begun to form an oxide layer.

9. The production method according to claim 4, characterized in that Before the drawing and forming process, a smelting process is also included, and the smelting process includes: Pour the copper raw materials into the power frequency melting furnace for electrolytic melting, and then transfer them into the holding furnace for insulation; During the electrolytic smelting process, the electrolytic plates of the power frequency smelting furnace are covered with charcoal for insulation; The industrial frequency melting furnace is a 5T melting furnace; The thickness of the charcoal covering is between 60mm and 100mm; The holding furnace is covered with graphite flakes; Covering thickness is greater than 10mm; The holding temperature of the holding furnace is between 1100° C. and 1180° C.

10. The production method according to claim 1, characterized in that Gradient grinding is used during the grinding process; The target grinding mesh is above 400 mesh; The thickness of single-side grinding is between 0.05mm and 0.5mm; The grinding speed is between 1 and 40 mm / min.

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