WO2018103132A1

WO2018103132A1 - High-bonding strength copper-aluminum composite conductive material and preparation method therefor

Info

Publication number: WO2018103132A1
Application number: PCT/CN2016/110430
Authority: WO
Inventors: 董晓文; 王连忠
Original assignee: 烟台孚信达双金属股份有限公司
Priority date: 2016-12-07
Filing date: 2016-12-16
Publication date: 2018-06-14
Also published as: KR102278579B1; CN106601324A; EP3553793A1; EP3553793B1; KR20190091502A; EP3553793A4; CN106601324B

Abstract

A high-bonding strength copper-aluminum composite conductive material and a preparation method therefor, comprising a clad copper layer and an aluminum core matrix; an interatomic bonded metallurgical bonding layer is formed between the clad copper layer and the aluminum core matrix; the thickness of the bonding layer ranges from 5 to 35um, and the bonding strength is greater than or equal to 40MPa; a copper-aluminum intermetallic compound is dispersedly distributed in the bonding layer; the components of a diffusion layer close to one side of a copper matrix are uniform, and the thickness of the diffusion layer is narrow; a diffusion layer close to one side of an aluminum matrix is of a reticular structure formed by a mixture of two or more components, and the thickness of the diffusion layer is wide. The bonding between copper and aluminum in the copper-aluminum composite material achieves a metallurgical bonding state, and the corresponding bonding strength is more than 40MPa; the thickness of a side copper layer of the copper-aluminum composite material is about 1.6 to 2 times the thickness of a planar copper layer; the thickness of the side clad copper layer is sufficient enough for large current impact and heat dissipation; and the elongation rate of the copper-aluminum composite material is greater than 30%. The present invention may carry out processing such as torsion, spiraling and side bending which is applied to new fields.

Description

High bond strength copper-aluminum composite conductive material and preparation method thereof

[0001] The present invention belongs to the technical field of composite materials, and in particular relates to a high bond strength copper-aluminum composite conductive material and a preparation method thereof.

Background technique

[0002] Copper-aluminum composite material, also known as copper-clad aluminum row, copper-clad aluminum busbar, has an outer layer of copper and a core made of aluminum. The existing copper-aluminum composite material generally has a combination of outer layer copper and core aluminum, which is a so-called copper-clad aluminum, and the outer layer of copper and the core aluminum are bonded together by a pressing force under solid state. In this combination, the bonding strength of the copper-aluminum interface is low, and the separation of copper and aluminum is easily caused by the external force. Under the high power microscope, there is no mutual diffusion layer between copper and aluminum. The microscope is magnified to 500~1000 times for observation. There is a clear gap at the interface between copper and aluminum, which shows the combination of copper-clad aluminum material under mechanical bonding. The intensity is lower. Patent "an improved copper-clad aluminum row and its preparation method" (Patent No.: CN201010591239.2), it is difficult to operate the aluminum rod through the molten copper liquid to form a copper-aluminum composite, since the melting point of aluminum is 660 ° C , far below the melting point of copper 1083 ° C, when the aluminum rod passes through the molten copper liquid helium will also melt and can not be compounded, this structure of copper-clad aluminum row can not guarantee the copper-aluminum interface in macroscopic and microscopic Bond strength.

[0003] Existing copper-aluminum composite materials in various application fields need to be processed by conventional bending, punching, milling, skeining, riveting, etc., as the product requirements are continuously improved, twisting The processing methods such as spiral and side bend are proposed. This requires that the copper-aluminum composite material can have better deformation ability and higher bonding strength, and ensure that the copper-aluminum interface is not damaged when the processing is completed. However, the elongation of the general copper-aluminum composite material is _{3 to} 20%, and it is difficult to achieve the processing requirements of torsion, spiral and side bend, and the surface of the product is prone to orange peel defects after processing, and the copper-aluminum interface is prone to splitting and splitting. The current density of the product surface distribution during the use of the poor product is extremely uneven, and the current density of the splitting and separating part is relatively large, resulting in heating or even burning through the separated part. In addition, galvanic corrosion may occur between the copper and aluminum in the splitting part, resulting in a safety accident.

[0004] As described above, the existing copper-aluminum composite material is disadvantageous in that: 1 the bonding performance between copper and aluminum is weak, The metallurgical bonding state of the composite material is not required, and the corresponding bonding strength is also low. 2 For the flat-width copper-aluminum composite material, there is a design problem in the thickness distribution of the cladding copper layer, and the thickness of the narrow-faced copper layer is thin. The current density is large, which is not enough to support large current impact, and the narrow-faced copper layer is easy to generate heat and has poor heat dissipation. 3 The existing copper-aluminum composite material processing performance can only achieve conventional bending, punching and milling. Machining of holes, rivet tapping, etc., cannot be realized for the processing of twisting, spiraling and side bending in new fields.

[0005] At present, there are roughly the following methods for producing copper-aluminum composite materials: 1 cladding welding method, coating copper skin on the outer surface of the aluminum rod, welding the copper skin joint by welding, and then performing multiple passes 2 drawing method; 2 casing rolling method, a method of inserting an aluminum rod into a copper tube, and rolling and pressing to form a solid phase between the copper tube and the aluminum rod; 3 filling core casting method, copper The bottom of the tube is closed at one end, and the molten aluminum liquid is poured into the copper tube. The aluminum liquid is solidified to form a copper-aluminum composite rod blank, which is then rolled and drawn; 4 hydrostatic extrusion method, using large-scale extrusion equipment The large-diameter copper tube and the pure aluminum rod are extruded under a large pressure; 5 the copper layer is plated on the surface of the aluminum core, and then rolled and formed.

[0006] The above method 1 and method 2 basically adopt a solid state bonding method, that is, plastic deformation of solid copper and aluminum metals by plastic deformation, and there is no obvious interdiffusion layer between copper and aluminum. The bonding strength is very low; the process of casting the aluminum liquid in the above method 3 is discontinuous and unstable, and the copper tube is easily burned through, and the length of the single casting is limited, so the product yield and production efficiency are low, and the product performance is unstable. The above method 4 has not been reported in China. The hydrostatic extrusion technology has been applied in the UK. The manufacturer Bmker uses a large hydrostatic extruder to squeeze the copper tube and the core aluminum rod to achieve a solid phase between copper and aluminum. Combined with various molds to form copper-aluminum composite materials, this method requires high requirements for equipment, and can not be continuously produced, with low production efficiency, high loss, complicated process requirements, high manufacturing cost, and is not suitable for mass production. The thickness of the electroplated copper layer in the above method 5 is limited, and the plating thickness is generally lower than the thickness of the copper tube used in other methods, and The copper layer is easily peeled off and cannot guarantee the quality of the product.

technical problem

In order to solve the above problems, the present invention provides a high bond strength copper-aluminum composite conductive material and a preparation method thereof.

Problem solution

Technical solution The technical solution of the present invention is achieved as follows: A high bond strength copper-aluminum composite conductive material, comprising a copper clad layer and an aluminum core matrix, wherein an interatomic space is formed between the clad copper layer and the aluminum core matrix The combined metallurgical bonding layer has a thickness of 5~35um, a bonding strength of ≥40Mp _a , a dispersed copper-aluminum intermetallic compound in the bonding layer, a uniform diffusion layer near the copper substrate side, and a narrow thickness. The diffusion layer near the side of the aluminum substrate exhibits a network structure in which two or more components are mixed, and the thickness is wide, and the thickness of the copper layer on the side of the flat-width copper-aluminum composite material is 1.6 to 2 times the thickness of the planar copper layer;

[0009] A method for preparing a high bond strength copper-aluminum composite conductive material, comprising the following process steps:

[0010] 1), molten aluminum

[0011] The raw material aluminum ingot was added to the aluminum melting furnace for melting, in a ratio of 1.5%. -5%. The content of A1B ₃ and 3%. -7%. The NH ₄ C1 is added to the aluminum melting furnace for high-purity decontamination and degassing. The amount of the furnace is 100kg-400kg, and the corresponding degassing stirring rod rotates at 100-400r/min. The flow rate of high-purity argon gas is controlled to 0.1-0.5IJmin, and the degassing time is controlled to 15~20min. After the gas is removed, the aluminum liquid can be used; the temperature of the aluminum liquid is controlled between 770 and 820 °C.吋 adjust the melting furnace power between 50~70kw;

[0012] 2), molten copper

[0013] The raw material standard cathode electrolytic copper plate is added to the oxygen-free copper melting furnace, the patina and the pollutants on the surface of the electrolytic copper plate are polished by a polishing machine, and the furnace body of the copper melting furnace is divided into three parts: a melting zone and a heat preservation zone. , in the static zone, the electrolytic copper plate is added to the melting zone, the feeding interval is 3~5min, the copper liquid temperature is maintained between 1150~1180 °C, the molten copper liquid flows into the heat preservation zone, and the temperature adjustment is needed, and the heat preservation is completed. After the copper liquid is transferred into the stationary area for waiting for copper to be used;

[0014] 3), copper-aluminum composite

[0015] The copper liquid produced in the first step and the aluminum liquid produced in the second step are recombined through respective flow passages, and the copper liquid enters the composite cavity through the copper pipeline, and the flow of the aluminum liquid through the core The aluminum pipe enters the composite cavity, and the two are formed in the composite furnace through the composite mold and the peripheral crystallizer and the secondary tertiary cooling device to form a copper-aluminum composite bar blank with copper and a core of aluminum, and the composite casting temperature is controlled to 1200±5°C, the temperature of the crystallizer cooling water is controlled at 50~60°C, the flow rate is controlled at 4~8L/min, and the crystallizer is connected to the secondary tertiary cooling device, and the cooling of the secondary tertiary cooling device. The flow rate of water is about 12~25L/min, and the speed of the bowing of the blank is controlled at 110~180mm/min; [0016] 4), rolled copper-aluminum composite rod blank

[0017] The copper-aluminum composite rod blank produced in the third step is rolled, the rolling mill is a two-roll reversible rolling mill, and the rolling mill is equipped with a turning device on both sides, which can automatically turn the material, and the roll is a box-shaped hole type system, The copper-aluminum composite bar billet with rectangular cross section is rolled into a copper-aluminum composite intermediate product with a flat and wide section, and the rolling nip roll is usually set to 2~3mm, and the rolling speed is 10~40m/min;

[0018] 5), side surface treatment

[0019] The rolled copper-aluminum composite rolling material is fed under the transmission of the conveying roller, and is driven at a constant speed under the pressing state, and enters the side surface treatment equipment, the grinding wheel of the equipment and the copper-aluminum composite rolling material. The sides of the contact are in contact with each other, and the surface of the contact surface of the material is polished by the high-speed rotation of the grinding wheel;

[0020] 6), plane surface treatment

[0021] The fifth step of the processed semi-finished copper-aluminum composite row, after the side is polished, the upper and lower surfaces are also processed, and the incoming material enters the plane processing equipment through the traction roller lead, and is pressed by the upper and lower rolls. Prevent the up and down swing, the incoming transmission speed is 3~5m/min, and the material is driven at the uniform speed of the traction device. The upper and lower planes of the copper layer are milled off by the processing equipment of the upper and lower planes. The milling cutter feeds 0.10~ 0.15mm, the copper layer is milled off by 0.1~0.15mm;

[0022] 7), drawing

[0023] The material processed after the sixth step is drawn, the first pass drawing processing rate is controlled at 25%~30<3⁄4, the processing rate is _≤30 <3⁄4, and the coiling or sawing is performed after drawing. Cut into a certain length of straight material, the entire drawing, coiling and sawing process are automatically controlled, and can be continuously operated;

[0024] 8), annealing

[0025] Annealing is the most important process before product molding, annealing temperature 295~345 °C, annealing and heat preservation time 3

~4.5h, then spray the tank to cool to room temperature;

[0026] (9), surface cleaning

[0027] The automatic feeding mechanism places the copper-aluminum composite row completed in the eighth step in the guiding groove, and starts the device. Under the driving of the conveying wheel, the copper-aluminum composite row first passes through the alkali washing box, and the box body is provided with a brush and a wind. Knife, brush is used to remove surface oil, air knife blows dry copper-aluminum composite row surface; then through a water spray device, water washes off residual lye on the surface, blows dry and enters the pickling tank, also in the pickling tank It is equipped with a brush and a wind knife. After the pickling process is completed, it is dried and washed into a passivation box. The passivation solution is configured in the passivation box according to the passivation process. After the passivation is completed, the oven is automatically dried, and the passivation box is taken out under the traction of the conveyor belt, and then the copper-aluminum composite row which is surface-cleaned and passivated is placed on the receiving rack by the automatic receiving device;

[0028] Preferably, the processing rate in the drawing process is: when the thickness h≥10 mm吋, 25%>the processing rate≤30<3⁄4

When 6mm≤thickness h < 10mm吋, 20<3⁄4> processing rate≤25<3⁄4; 3mm≤thickness h < 6mm吋, 15%

〉Processing rate _≤ 20<3⁄4; thickness h < 3mm吋, processing rate ≤ 15%;

[0029] Preferably, the annealing process uses tank annealing and in-line induction annealing;

[0030] Preferably, the copper-aluminum composite row having a specification width of 80 mm or more is subjected to in-line induction annealing, and the copper-aluminum composite row having a specification of 80 mm or less is subjected to tank annealing;

[0031] Preferably, the rolling process adopts a hole type nine-pass drawing process;

[0032] Preferably, the drawing process may adopt a disk pulling, hydraulic drawing and crawler drawing process. Width specification ≤ 30 mm, using pull-pull or hydraulic drawing or crawler drawing; 30mm <width specification ≤ 120mm, hydraulic drawing or crawler drawing; 6m/min ≤ disk pulling speed ≤ 60111/0101, 50m/ Min≤ crawler drawing speed ≤80m/min, hydraulic drawing speed ≤8m/mino

Advantageous effects of the invention

Beneficial effect

[0033] The beneficial effects of the present invention are: the high strength copper-aluminum composite conductive material of the present invention is bonded to the metallurgical bonding state, and the corresponding bonding strength is greater than 40 MPa; the copper layer of the copper-aluminum composite material is thicker than the plane , about 1.6 to 2 times the thickness of the flat copper layer, the thickness of the side cladding copper layer is sufficient to meet the large current impact and heat dissipation; the elongation of the copper-aluminum composite is more than 30%, for the new field of application of torsion, spiral and side bend Processing can be achieved.

[0034] 1) The invention achieves the high-purity and low-gas-purifying aluminum by the specific treatment of the aluminum liquid and the degassing process, and the control of the cooling capacity of the furnace body reduces the energy consumption and heat loss. The amount is 6~8%.

[0035] 2) The surface of the electrolytic copper plate and the contaminants are polished by a polishing machine, and the furnace body is divided into three sections to achieve a melting, adjusting, and stable state, the sealed furnace cover, and the molten copper surface layer has The graphite ball and the charcoal are covered to protect against oxidation, so as to achieve the effect of low hydrogen and low oxygen, and the hydrogen and oxygen content is controlled below 10 PPM, and the gas content of the copper liquid can be reduced to avoid potential bubbles in the subsequent production products.

[0036] 3) The copper-aluminum composite temperature is controlled to 1200±5° C., so that the fluidity of the copper liquid aluminum liquid is optimal, and the superheat degree satisfies the solidification requirement. The secondary cooling flow is about three times the cooling flow of the crystallizer, and the cooling water flow The amount is about 12~25L/min, which acts to take away the latent heat of crystallization generated by the solidification of the aluminum core, so that the cooled billet reaches a normal temperature state.

4) By casting temperature and cooling, the composite casting temperature is controlled to 1200±5°C, the traction speed is controlled to 110~180mm/, the mold cooling water return temperature is controlled to 50~60°C, and the flow control is up to 4 ~8L/min, the thickness of the copper-aluminum bonding layer is required to control the thickness of the bonding layer to 5~35μηι, and there is a distinct diffusion layer between the copper and aluminum substrates, that is, the metallurgical bonding layer, and the inter-atomic bonding between copper and aluminum.

[0038] 5) The roll adopts a box-shaped hole type system, which is beneficial to enhancing the interfacial bonding strength of the copper-aluminum composite row, and the bonding strength is greater than 40 MPa (the copper-aluminum composite row prepared by other methods is difficult to achieve the bonding strength), and the same can be shared. The reduction of the rolling in each subsequent pass avoids the rolling reduction phenomenon caused by the large amount of reduction in the subsequent passes and the hardening of the material.

[0039] 6) The side treatment and the surface treatment processing replace the conventional surface treatment method, which increases the processing speed by 2.2 times, and completely eliminates defects such as indentations, casting lines, and triangular cracks on the surface of the material.

[0040] 7) The drawing process can be automatically and continuously operated, and the same is equipped with a receiving and unwinding device, which can take up the coil material, and the production of the straight material can be cut according to the production requirements, and theoretically, the material can be infinitely long.

Embodiments of the invention

[0041] For better understanding and implementation, a high bond strength copper-aluminum composite conductive material of the present invention and a preparation method thereof are described in detail below: A high bond strength copper-aluminum composite conductive material in the present invention, including an aluminum row substrate And a copper layer, a metallurgical bonding layer formed with an atomic bond between the cladding copper layer and the aluminum core substrate, and the bonding layer thickness is controlled to 25 μηι, the bonding layer is different from the ordinary copper-aluminum bonding, and the bonding strength is required to be 40 MPa, wherein the dispersion is Copper-aluminum intermetallic compound CuAl ₂ , Cu ₉ Al ₄ , CuAl.

[0042] A casting mold with a thickness of a copper layer is designed, and a thicker product of a narrow-faced copper layer is produced in a subsequent manner by alternately rolling a flat hole and a vertical hole, so that the thickness of the side copper layer of the copper-aluminum composite row is made. It is 1.8 times the thickness of the flat copper layer. This kind of product is in line with the electric principle of "skin effect", which solves the problem of narrow heat dissipation and insufficient current carrying of the flat and wide copper-aluminum composite.

[0043] A method for preparing a high bond strength copper-aluminum composite conductive material in the present invention comprises the following steps: [0044] 1. Casting a copper-aluminum composite rod blank

[0045] 1. Aluminum melting [0046] A raw material 1070 (or equivalent 1060) type aluminum ingot is added to the aluminum melting furnace for melting, which will be in a ratio of 3%. The content of A1B ₃ and 5%. The NH ₄ C1 is added to the aluminum melting furnace. The aluminum melting furnace is an intermediate frequency induction melting furnace, and the rated capacity of the aluminum melting furnace is 500 KW. Each time the amount of furnace is 200kg, the corresponding degassing stir bar has a rotation speed of 20 Or/min, the flow rate of the degassing mixer is high to pure argon gas to 0.2IJmin, and the degassing time is controlled to 18min. The parameter ratio can be used to remove the gas from each furnace aluminum solution. The temperature of the aluminum liquid is controlled to 780 ° C, and the power of the aluminum melting furnace is adjusted to be between 60 kW. The temperature of the control range can meet the temperature requirement of the continuous casting process. In addition, reducing the cooling water can reduce the heat loss, and the maximum Ground reduces energy consumption.

[0047] 2. Copper melting

[0048] The raw material standard cathode electrolytic copper plate is added to the melting zone of the oxygen-free copper melting furnace, and the patina and the pollutants on the surface of the electrolytic copper plate are polished by a polishing machine, and the molten copper liquid flows into the heat preservation zone every time the feeding interval is 3 to 5 minutes. After the completion of the heat preservation, the copper liquid is transferred into the stationary area to wait for the copper to be used. The furnace body of the copper melting furnace is divided into three parts: a melting zone, a heat preservation zone and a stationary zone. The electrolytic copper plate is added to the melting zone, the temperature of the copper liquid is maintained between 1150 and 1180 ° C, and the temperature of the holding zone and the stationary zone is maintained at 1200 ± 10 ° C. This control can compensate for the crystallization potential required for the solidification process of the copper liquid. In addition, it can supplement the thermal energy required for the copper-aluminum composite process to achieve metallurgical bonding.

[0049] The whole molten copper furnace body has a closed furnace cover, and the surface of the molten copper liquid is covered with graphite balls and charcoal to protect the copper liquid from oxidation and inhalation, so as to achieve the effect of low hydrogen and low oxygen, and control the hydrogen and oxygen content. Below 10 ppm, reducing the gas content of the copper solution can avoid potential bubbles in subsequent production products.

[0050] 3. Copper-aluminum composite

[0051] The copper liquid and the aluminum liquid produced in the above steps 1 and 2 are recombined through respective flow passages, and the copper liquid is cooled by a crystallizer to form a solidified copper tube, and the core aluminum liquid enters the inside of the copper tube through the flow aluminum pipe. Then, the solidified core aluminum is formed by cooling the copper sleeve and the copper tube inside the crystallizer, and finally cooled by a secondary cooling device to form a copper-aluminum composite rod blank. The copper liquid enters the composite cavity through the copper pipeline, and the composite casting temperature is controlled to 1205 ° C. The aluminum liquid enters the composite cavity through the flow aluminum pipe of the core, and the two pass through the composite mold and the peripheral crystal in the composite furnace. And the secondary tertiary cooling device forms a copper-aluminum composite rod blank whose outer layer is copper and whose core is aluminum.

[0052] The temperature of the return water of the crystallizer cooling water is controlled to 55 ° C, the flow rate is controlled to 6 L / min, and the second cooling is connected to the crystallizer, and the flow rate of the second cooling water is about 18 L/min, which is crystallization. Three of the cooling water flow The pulling speed of the bar blank is controlled to 150 mm/min. There is a distinct interdiffusion layer between the copper and aluminum substrates, that is, the metallurgical bonding layer, and the inter-atomic bonding between the copper and aluminum is achieved, and the intermetallic compounds CuAl ₂ , Cu ₉ Al ₄ and CuAl are dispersed in the bonding layer. The diffusion layer on the side close to the copper substrate is uniform in composition and narrow in thickness, and the diffusion layer on the side close to the aluminum substrate exhibits a network structure in which two or more components are mixed, and the thickness is wide.

[0053] Second, rolling

[0054] 1) Rolling

[0055] The A1 is inverted by 90° by the turning device of the reversing rolling mill, and the appropriate roll gap is adjusted, and the vertical hole type E ceremony is adopted, and the pressing ratio is also significantly different according to the specifications of the casting blank and the rolling specifications. . Usually, small-size slabs are used to roll large-size copper-aluminum composite sputum, because the rolling material needs to have sufficient widening, so the reduction ratio is relatively small; and the large-size slab is used to roll small-sized copper-aluminum composite sputum, because The rolling material needs to have a large widening, so the pressing ratio is relatively large, and the pressing ratio is between 5% and 23<3⁄4. The slope of the side wall of the vertical hole type E is generally between 3° and 9°, and the slope of the side wall is too large. The higher the requirement for the turning device, the rolling operation after the turning is not stable, and the next hole type is entered. It is difficult to align, and the biting of the rolling material is prone to distortion. In addition, the greater the slope, the more severe the wear of the strip on the sidewall of the hole, and the easier it is to adhere to the sidewall of the hole, and the rolling There is no benefit in the strength of the joint, mainly in the vertical rolling. The flat hole type is not so obvious because the groove depth is relatively small. In addition, the side wall slope should not be too small, and the side wall slope is too small to hinder the biting and throwing of the rolling material, and is not conducive to the heavy truck roll, resulting in poor utilization of the roll.

[0056] 2) First pass vertical hole rolling (vertical rolling)

[0057] The A1 is turned over by 90° by the turning device of the reversing rolling mill, and the vertical hole type E is used, and the pressing ratio is between 20%.

. The slope of the side wall of the vertical hole type E is generally 7. Between the rolling passes through the first pass is called A2.

[0058] 3) second pass flat rolling

[0059] The A2 is inverted by 90° by the turning device of the reversing rolling mill, and the appropriate roll gap is adjusted, and the flat hole type F rolling is used, and the pressing ratio is 55%, and the side wall inclination of the flat hole type F is 14°. Between the two passes, the surface state of the rolled material after rolling is roughened by roughening, and the rolled product obtained by this rolling is called A3.

[0060] 4) Second pass rolling

[0061] The A3 is turned by 90° by the turning device of the reversing rolling mill, and the appropriate roll gap is adjusted, and the vertical hole type G rolling is adopted.

, the reduction ratio is 15%, the side wall slope of the flat hole type G is between 5°, and the rolled material obtained by this crucible is called A4.

[0062] 5) Third pass flat rolling The A4 is inverted by 90° by the reversing mill's turning device, and the appropriate roll gap is adjusted. The flat hole type H is rolled, the reduction ratio is between 22%, and the side hole slope of the flat hole type H is between 13°. The rolling material produced by this crucible is called A5.

[0064] 6) Third pass rolling

[0065] The A5 is turned by 90° by the turning device of the reversing rolling mill, and the appropriate roll gap is adjusted. The vertical hole type I is used, and the pressing ratio is usually between 8%, and the side wall slope of the vertical hole type I is 5. Between the two, the rolled material is called A6.

[0066] 7) Fourth pass flat rolling

[0067] The A6 is turned over by 90° by the turning device of the reversing rolling mill, and the appropriate roll gap is adjusted, and the flat hole type J is used, the pressing ratio is between 16%, and the side wall slope of the flat hole type J is 8 Between ° and 10 °, the rolling material produced by this crucible is called A7.

[0068] 8) Fourth pass rolling

[0069] The A7 is turned over by 90° by the turning device of the reversing rolling mill, and the appropriate roll gap is adjusted. The vertical hole type K is used, and the pressing ratio is usually between 6%, and the side wall slope of the vertical hole type K is 3. Between this and the last pass, the final rolling is required, and the shrinkage size of the rolling stock needs to be strictly controlled. The rolling material obtained by this boring is called A8.

[0070] 9) fifth pass flat rolling

[0071] The A8 is turned by 90° by the turning device of the reversing rolling mill, and the appropriate roll gap is adjusted. The flat hole type L is used, and the pressing ratio is usually between 15%, and the side wall slope of the flat hole type L is Between 12°, this pass is the last rolling before drawing, and the discharge size of the rolling material needs to be strictly controlled, that is, the proper drawing amount is reserved, which has a significant influence on the surface state of the drawing material. . The rolling material produced by this crucible is called A9.

[0072] Third, side throw

[0073] The rolled copper-aluminum composite rolling material enters the side throwing machine under the transmission of the conveying roller, and the side throwing machine components are 4 units, and the two sides of the side throwing machine are polished on the upper side, and the side throwing machine is followed by two sets of grinding. Plane, the polishing material is sandpaper thousand impeller, the narrow side grinding amount is controlled at 0.12mm, and the side throwing equipment used has pressing device, which can prevent the copper-aluminum composite rolling material from swinging up and down or swinging left and right, and the narrow side grinding amount should be grouped. To avoid excessive grinding of a single pass, grouping for side grinding should be done by alternately grinding two narrow sides.

[0074] Fourth, milling surface

[0075] The incoming material is a coiled copper-aluminum composite row, which enters the milling machine through the traction roller lead, and the incoming material is pressed by the upper and lower rollers to prevent the upper and lower swings, the incoming conveying speed is 4 m/min, and the milling cutter is installed in the circle. Roller cutter, roller cutter The blade has a spiral shape and is shaped like a circular roll cutter. The milling cutter is divided into two groups, the first group is processed on the upper plane, the second group is processed on the lower plane, the milling cutter feed amount is 0.13 mm, and the copper layer is milled off by 0.12 mm. The copper scrap of the milling surface is recovered by the blower through the pipe.

[0076] five, drawing

[0077] Drawing process steps:

[0078] 1) Taro. The length of the incoming mill head is 250mm, and the copper and aluminum joints at the end of the material are combined. The separation of copper and aluminum is not observed visually. The optimum thickness of the steamed bread is 0.3mm smaller than the thickness of the mold. The optimum length of the steamed bread is 120 mm after the die. This kind of hoe is easier to pull and there is no breakage.

[0079] 2) Drawing. The first pass can be larger, and the machining rate is controlled at about 25%. The maximum is not more than 30<3⁄4, the thickness is 12mm吋, and the processing rate φ (9=(1-Fl/F0)xl00%) should be controlled. 25<3⁄4, but it should be noted that the thickness of the drawing should not exceed 4mm; and as the thickness is thinner, the more the drawing passes, the smaller the processing rate should be.

[0080] 3) Receiving. The material is automatically sawed, and the length of the blanking is set to be 6m. After pulling out the straight material, 3 straight materials are randomly selected to check the straightness, length and appearance to ensure the straightness, length and table of the straight material. The view meets the production requirements. Flatness requires that the narrow side bend of any lm length should be no more than 2mm, the wide side bend should be no more than 5mm; the length tolerance should be ±3% of the length of the blank. .

[0081] Sixth, annealing

[0082] The copper-aluminum composite row having a specification width of 80 mm or more is subjected to in-line induction annealing. For example, a copper-aluminum composite row having a specification width of 100 m is transported through the induction coil region through a transmission bearing to generate an induced current temperature inside the copper-aluminum composite row, and induction annealing is performed. The current is set to 140A, and the rapid cooling by the water jet cooling device at the outlet reaches the annealing effect of rapid heating and rapid cooling. The induction annealing feed speed is 45mm/s. On-line induction annealing can monitor the temperature of the copper-aluminum composite row through the infrared thermometer of the discharge port. The annealing temperature is roughly set between 295 and 345 °C.

[0083] The copper-aluminum composite row with the specification below 80mm is annealed by a can, for example, the specification width is 60mm, and then the copper-aluminum composite is fixed to the 6.3m and then mounted on the material rack, and is loaded into the heated tank by the hanging crane, and the tank is bright. Annealing is based on different furnace loadings. The annealing time is about 4.2h. It is fed into the heating furnace through the button of the control cabinet. The vacuum is applied for 12min, and the argon gas is filled to 0.12MPa. The annealing temperature is set according to the specifications of the copper-aluminum composite row. °C, according to the amount of furnace installed, the heating and insulation chamber is used for tank-type bright annealing. Tank water spray cooling by spray cooling Water is sprayed around the pipe to ensure rapid and even cooling of the tank.

[0084] Changing the heat treatment method improves the plastic properties of the material, and the in-line induction annealing causes the material temperature to be extremely short.

(Generally, it can be 6~10s). It is raised to about 350°C, and then the temperature is lowered to normal temperature by rapid water cooling. This annealing method allows the crystal grains inside the copper layer to recrystallize, and the crystal grains are not grown, and the bonding layer of the copper-aluminum interface is not destroyed, so that the plastic processing property of the material is good. Through this annealing method, the elongation of the copper-aluminum composite material can be controlled to 30 to 35%, which can meet the requirements of processing methods such as torsion, spiral and side bend.

[0085] Seven, surface cleaning

[0086] The copper-aluminum composite row is placed on the platform of the automatic feeding mechanism, and the automatic feeding and receiving device sucks the surface of the copper-aluminum composite row through the vacuum suction cup, and moves up and down and left and right through the screw, and the copper-aluminum composite row is placed on the platform. In the guiding groove, the copper-aluminum composite row is firstly washed by the transfer wheel, and the box body is provided with a brush and a wind knife. The brush is used to remove the surface oil, and the air knife blows the surface of the copper-aluminum composite row; After a water spray device, the residual lye on the surface is washed off, dried and then entered into the pickling tank. The pickling box is also equipped with a brush and a wind knife. After the pickling process, it is dried and then passivated. In the box, the passivation solution is sprayed onto the surface of the copper-aluminum composite row in the passivation box. After the spray passivation is completed, it is automatically dried. The passivation box is pulled under the traction of the conveyor belt, and then the surface is cleaned bluntly by the automatic receiving device. The finished copper-aluminum composite row is placed on the receiving rack to complete the entire surface cleaning process.

Claims

Claim

[Claim 1] A high bond strength copper-aluminum composite conductive material comprising a clad copper layer and an aluminum core substrate, characterized in that a metallurgical bonding layer is formed between the clad copper layer and the aluminum core matrix to form an interatomic bond

The bonding layer has a thickness of 5 to 35 um, a bonding strength of ≥40 Mp _a , a dispersed copper-aluminum intermetallic compound in the bonding layer, a uniform diffusion layer near the copper substrate side, and a narrow thickness near the side of the aluminum substrate. The diffusion layer exhibits a network structure in which two or more components are mixed, and the thickness is wide. The thickness of the copper layer on the side of the flat-width copper-aluminum composite material is 1.6 to 2 times the thickness of the planar copper layer.

[Claim 2] A method of producing a high bond strength copper-aluminum composite conductive material according to claim 1, which comprises the following process steps:

1), molten aluminum

The raw material aluminum ingot was added to the aluminum melting furnace for melting, in a ratio of 1.5%. ~5%. The content of A1B ₃ and 3%. ~7%. The NH ₄ C1 is added to the aluminum melting furnace for high-purity decontamination and degassing. The amount of the furnace is 100kg~400kg, and the corresponding degassing stir bar rotates at 10 0~400r/min. The flow rate of the high-purity argon gas into the mixer is controlled to 0.1~0.5L/min, and the degassing is controlled to 15~20min. The aluminum liquid can be used after the gas is removed. The temperature of the aluminum liquid is controlled at 770~820°C. Between, the melting furnace power is 50~70kw;

2), molten copper

The standard cathode electrolytic copper plate of the raw material is added to the oxygen-free copper melting furnace, the patina and the contaminants on the surface of the electrolytic copper plate are polished by a polishing machine, and then added to the melting zone, and the temperature of the copper liquid is maintained between 1150 and 1180 ° C, and melted. The copper liquid flows into the heat preservation zone, and the copper liquid after the completion of the heat preservation is transferred into the stationary zone to wait for copper to be used;

3), copper-aluminum composite

The aluminum liquid produced in the above step 1 and the copper liquid produced in the second step are recombined through respective circulation channels, and the copper liquid enters the composite cavity through the copper flow pipe, and the aluminum liquid enters through the flow aluminum pipe of the core. Into the composite cavity, the two in the composite furnace through the composite mold and the peripheral crystallizer, the secondary tertiary cooling device to form the outer layer of copper, the core is aluminum copper and aluminum composite rod blank, composite casting temperature control to 1200 ± 5 °C, crystallizer cooling water return water temperature is controlled at 50~60 °C, flow The quantity is controlled at 4~8L/min. The second cooling device is connected to the crystallizer. The flow rate of the cooling water in the second three times device is about 12~25L/min, and the pulling speed of the bar blank is controlled at 110~180mm. /min;

4), rolled copper-aluminum composite rod blank

The copper-aluminum composite rod blank produced in the third step is rolled. The rolling mill is a two-roll reversing mill. The rolling mill is equipped with a turning device on both sides, which can automatically turn the material. The roll is a box-shaped hole type, and the rectangular section is The copper-aluminum composite bar billet is rolled into a copper-aluminum composite intermediate product with a flat and wide section, the rolling nip roll is set to 2~3mm, and the rolling speed is 10~40m/min;

5), side surface treatment

The rolled copper-aluminum composite rolled material is fed by the conveying roller under the transmission of the conveying roller, and is driven at a constant speed under the pressing state, and enters the side surface treatment equipment, the grinding wheel of the equipment and the side phase of the copper-aluminum composite rolling material. Contact, through the high-speed rotation of the grinding wheel, the surface of the contact surface of the material is polished;

6), flat surface treatment

After the processed semi-finished copper-aluminum composite row in step 5, the upper and lower surfaces are also treated after the polishing process, and the incoming material enters the plane processing equipment through the traction roller lead, and is pressed by the upper and lower rollers to prevent the upper and lower swings. The feeding speed of the incoming material is 3~5m/min. The material of the upper and lower planes is milled off by the processing equipment of the upper and lower planes. The cutting amount of the milling cutter is 0.10~0.15mm. The copper layer is milled to 0.1~0.15mm;

7), drawing

The incoming material processed after the sixth step is drawn, and the processing rate of the first pass drawing is controlled at 25 %~. 'The processing rate is ≤30%. After drawing, it can be coiled or sawn into a certain length of straight material. The whole drawing, coiling and sawing process are automatically controlled and can be operated continuously;

8), annealing

Annealing is the most important process before the product is formed. The annealing temperature is 295~345°C, the annealing temperature is between 3~4.5h, and then the tank is sprayed to cool to room temperature.

(9), surface cleaning The automatic feeding mechanism places the copper-aluminum composite row completed in the eighth step in the guiding groove, and starts the equipment. Under the driving wheel, the copper-aluminum composite row is firstly washed by the alkali washing tank, and the box body is provided with a brush and a wind knife. The brush is used to remove the surface oil, and the air knife blows the surface of the copper-aluminum composite row; then, after a water spray device, the residual lye on the surface is washed off, dried and then enters the pickling tank, and the pickling box is also provided with hair. Brush and air knife, after pickling treatment, pass through a water washing and drying, then enter the passivation box. The passivation solution is arranged in the passivation box according to the passivation process. After the spray passivation is completed, it is automatically dried, under the traction of the conveyor belt. The passivation box is taken out, and then the copper-aluminum composite row which has been surface-cleaned and passivated is placed on the receiving rack by the automatic receiving device.

The method for preparing a high bond strength copper-aluminum composite conductive material according to claim 2, wherein the processing rate in the drawing process is: when the thickness is h ≥ 10 mm 吋, 25% > the processing rate _≤ 30 <3⁄4; When 6mm≤ thickness h < 10mm吋, 20<3⁄4> processing rate ≤25<3⁄4; 3mm ≤ thickness h < 6mm吋, 15<3⁄4> processing rate ≤20<3⁄4; thickness h < 3mm吋, processing rate ≤ 15 .

A method for preparing a high bond strength copper-aluminum composite conductive material according to claim 2, wherein the annealing process employs tank annealing and in-line induction annealing.

The method for preparing a high bond strength copper-aluminum composite conductive material according to claim 4, wherein the copper-aluminum composite row having a specification width of 80 mm or more is subjected to in-line induction annealing, and the copper-aluminum composite row having a specification of 80 mm or less is used as a can. Annealing.

The method for preparing a high bond strength copper-aluminum composite conductive material according to claim 2, wherein the rolling process adopts a hole type nine pass rolling process.

Method for preparing high bond strength copper-aluminum composite conductive material according to claim 2 or 3

, characterized in that the drawing process can adopt a disk pulling, hydraulic drawing and crawler drawing process, and the width specification is ≤301^^ using a pull-pull drawing or a hydraulic drawing or a crawler drawing; 3011^1 <width specification ≤ 120mm, hydraulic drawing or crawler drawing; 6m/min≤disk pulling speed≤60m

/min, 50m/min≤ crawler drawing speed ≤80m/min, hydraulic drawing speed ≤8m/min.