A device and method for improving the shape of a finished sheet of ultrathin copper alloy ribbon

Abstract

The application discloses a device and method for improving the plate shape of an ultrathin copper alloy thin strip product, which comprises a lower package angle deflection tension single roller and an upper package angle deflection tension single roller, the lower package angle deflection tension single roller is rotationally arranged at the lower side of the outlet of a continuous heat treatment furnace body and is connected with an external driving mechanism, and is a driving roller; the upper package angle deflection tension single roller is rotationally arranged at the upper side of the inlet of the continuous heat treatment furnace body, and is a driven roller without driving; the copper alloy thin strip is rotated under the double actions of the self weight and the lower package angle deflection tension single roller, and enters the continuous heat treatment furnace body from outside the furnace; the high density characteristics (the density is 8.9*10 3 kg / m 3 ) of the copper alloy thin strip are utilized; the strip suspension relies on the self weight to control the tensile stress; the structure is simple; the investment cost is low; and the plate shape quality of the copper alloy thin strip with the thickness of 0.03-0.5 mm can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal strip production technology, and in particular to an apparatus and method for improving the finished product shape of copper alloy thin strip with a thickness of 0.03~0.5mm. Background Technology

[0002] Copper and copper alloy sheets and strips are the main product types used in copper processing, and are widely used in aerospace, defense, communications, and electronic information fields, such as manufacturing new energy interconnects, photovoltaic solar panels, automotive connectors, and lithium batteries.

[0003] The development trend of copper and copper alloy strips is towards ultra-thinness and alloying. Previously, the mainstream product thickness was 0.15~1.5mm, but it has now been reduced to 0.03~0.5mm. Previously, the mainstream products were pure copper and brass strips, but currently, the products with the largest market demand are high-copper alloy strips with added microalloying elements such as Ti, Mg, Fe, Cr, Ni, and Sn. At the same time, the defense, aerospace, and communications industries have increasingly higher quality requirements for these thin-gauge copper alloy strips, especially regarding dimensional accuracy, thickness tolerance, surface finish, anisotropy, high-temperature resistance, and creep resistance. These high-grade copper alloy strips are also referred to as "high-precision copper strips" by the industry both domestically and internationally.

[0004] Since the downstream secondary processing steps of copper alloy strips mainly involve cutting, stamping, and etching, to avoid deformation, warping, unevenness, and anisotropy-induced lugs in the finished product, the copper alloy strips are required to have extremely low residual internal stress and extremely high plate quality. Currently, the market requires high-precision copper strip products with a thickness of 0.03~0.5mm to have a residual stress of less than 5% and a plate quality requirement of 1~3I, but currently, the plate quality of domestically produced copper alloy strips of this thickness can only be controlled to 5~7I.

[0005] Currently, the main domestic processes for reducing residual stress and improving the finished product profile of copper and copper alloy strips include the following. However, the following problems exist when producing copper alloy thin strips with low residual stress, especially those with a profile quality of 1~3I and a thickness of 0.03~0.5mm: (1) A bell-type heat treatment furnace is used to perform heat treatment processes such as multi-roll stacking annealing of 4 to 6 rolls of copper alloy strip. However, when large and heavy strips with an outer diameter of Φ1200~Φ1800mm are subjected to overall heat treatment, there is unevenness between the outer side and the core of the roll, resulting in poor product performance consistency. The bell-type heat treatment furnace is suitable for annealing strips with a thickness of 0.5mm or more, because when producing thin strips of 0.03~0.5mm, the strip layers are prone to adhesion, often making production impossible. At the same time, the bell-type heat treatment furnace cannot achieve tensile deformation of thin copper alloy strips under hot conditions, and cannot improve the quality of the strip shape.

[0006] (2) A tension straightening machine is used to perform 1% to 5% cold stretching deformation on copper alloy strips using a two-stage S-roll system, while simultaneously using small-diameter rolls of the 23 to 29 roll system for cold leveling. This method can significantly reduce the residual stress inside the finished product when producing ordinary copper, brass, and other low yield strength strips, controlling the plate quality to a minimum of 3 to 5I. However, when producing high copper alloy thin strips with added microalloying elements such as Ti, Mg, Fe, Cr, Ni, and Sn, the plate quality can only be controlled to a minimum of about 5I. At the same time, because microalloyed copper alloys have higher strength, the residual stress often reappears after cold stretching and leveling, resulting in various warping, unevenness, and earing issues during subsequent stamping, etching, and cutting. In addition, the minimum thickness of copper alloy thin strips produced by tension straightening machines worldwide is currently 0.05 mm, making it impossible to produce products with a thickness of less than 0.05 mm.

[0007] (3) In view of the drawbacks of bell-type heat treatment furnaces being unsuitable for heat treatment production such as annealing of thin copper alloy strips, some domestic and foreign manufacturers have adopted a process of uncoiling large coils of heavy copper strips → unfolding single-layer continuous heat treatment → coiling to improve the uniformity of heat treatment such as annealing and avoid interlayer adhesion of the strip coils. However, due to the high heat treatment temperature of copper strips, such as the solution heat treatment temperature of high copper alloys above 800~850℃, and the fact that it is impossible to set up devices such as pinch rollers and S rollers in the furnace to convey the strip and achieve tension control when the strip is thin and hot, their production line only sets up S roller groups, guide rollers, jumping rollers and other components outside the continuous heat treatment furnace body to control the tension outside the furnace in the hot state, so as to realize the tension establishment, conveying and production operation of the thin strip between various equipment components in the non-heat treatment section, as shown in the appendix to the instruction manual. Figure 1 As shown. Inside the furnace body for heat treatment processes such as annealing, an upper airflow injection device and a lower airflow injection device are used to suspend and control the copper alloy strip. When F... 向上浮力 > (F 向下浮力 When the weight of the thin strip is within a certain range (plus its own weight), the thin strip can meet the requirements for suspension-through heat treatment. However, the thin strip in the hot state is basically in a multi-stage S-shaped and tension-free suspension state, as shown in the attached instruction manual. Figure 2 As shown, it is impossible to achieve flat tension stretching and control under hot conditions, thus making it impossible to effectively control and improve the quality of the strip. Extensive production practice also shows that single-sheet unfolding continuous heat treatment helps to improve the uniformity of copper strip annealing and effectively reduces the residual stress generated during the previous cold rolling process. However, the quality of the thin strip actually decreases after passing through the heat treatment furnace. After exiting the furnace, it can only be improved by cold tension stretching and leveling using S-roll groups, guide rollers, and jumping rollers outside the furnace body on the production line.

[0008] In summary, none of the three current process technologies applied in this field can achieve the production objective of improving the sheet quality of 0.03~0.5mm thick copper alloy strips to 1~3I. Therefore, we propose a device and method for improving the finished sheet quality of ultra-thin copper alloy strips. Summary of the Invention

[0009] The technical problem this invention aims to solve is to overcome existing defects and provide an apparatus and method for improving the finished product shape of ultra-thin copper alloy strips, utilizing the high density characteristic of copper alloy strips (density of 8.9 × 10⁻⁶). 3 kg / m 3 The method of controlling tensile stress by suspending the strip and relying on its own weight is simple in structure and low in investment cost. It can effectively improve the plate quality of copper alloy thin strips with a thickness of 0.03~0.5mm and can effectively solve the problems in the background technology.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a device for improving the finished sheet shape of ultra-thin copper alloy strip, comprising a continuous heat treatment furnace body, a lower corner deflecting tension single roller and an upper corner deflecting tension single roller. The lower corner deflecting tension single roller is rotatably disposed on the lower side of the furnace body outlet and connected to an external drive mechanism, serving as the active roller; the upper corner deflecting tension single roller is rotatably disposed on the upper side of the furnace body inlet, serving as the passive roller without drive. The copper alloy strip rotates under the combined action of its own weight and the lower corner deflecting tension single roller, allowing the copper alloy strip outside the furnace to enter the continuous heat treatment furnace body. The self-weight of the copper alloy strip suspension section between the upper and lower corner deflecting tension single rollers forms a two-stage stepped tensile stress control on the strip during the heat treatment process.

[0011] As a preferred embodiment of the present invention, it further includes an upper air exchange device and a lower air exchange device. The upper air exchange device is uniformly arranged above the copper alloy strip suspension section inside the continuous heat treatment furnace body; the lower air exchange device is uniformly arranged below the copper alloy strip suspension section inside the continuous heat treatment furnace body.

[0012] The present invention also provides a method for improving the finished sheet shape of ultra-thin copper alloy strip, comprising the following steps: S1. An upper wrap angle deflecting tension single roller is set on the inlet side of the continuous heat treatment furnace body, and a lower wrap angle deflecting tension single roller is set on the outlet side, forming a high and low roller arrangement structure. The lower wrap angle deflecting tension single roller is driven by an external motor, thereby realizing the copper alloy strip with a certain wrap angle relationship to it running towards the outlet direction; the upper wrap angle deflecting tension single roller is a driven roller without motor drive. It rotates under the dual action of the weight of the copper alloy strip with a certain wrap angle relationship to it and the drive of the lower wrap angle deflecting tension single roller, thus realizing the copper alloy strip outside the furnace entering the continuous heat treatment furnace body; S2. Due to the high density of copper alloy strip, the copper alloy strip is suspended between the upper wrap angle bias tension roller and the lower wrap angle bias tension roller. The weight of the copper alloy itself can form a two-stage stepped tension control for the strip in the hot state during the heat treatment process. The first stage of high tension control is formed at the inner contact point between the copper alloy strip in the suspended section and the upper wrap angle bias tension roller, and the second stage of low tension control is formed at the inner contact point between the copper alloy strip in the suspended section and the lower wrap angle bias tension roller. S3. The inlet tensile stress range of the copper alloy strip on the inlet side of the continuous heat treatment furnace body, formed at the outer contact point between the upper wrap angle deflector tension single roller and the external inlet roller group is controlled to be 2~3 kg / mm. 2 The outlet tension stress ranges from 2.5 to 4.5 kg / mm², achieved by controlling the contact point between the copper alloy strip on the outlet side of the continuous heat treatment furnace body and the lower wrap angle deflector tension roller at the outer side of the roller assembly. 2 ; S4. The upper air exchange device located on the upper side of the continuous heat treatment furnace body generates a downward buoyancy force on the suspended section of the copper alloy strip, and the lower air exchange device located on the lower side of the continuous heat treatment furnace body generates an upward buoyancy force on the suspended section of the copper alloy strip. The relationship between the upward buoyancy force, the downward buoyancy force, and the self-weight of the strip satisfies F 向上浮力 =(F 向下浮力 +The weight of the suspension thin strip).

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. Given the current industry limitations in achieving tension control of copper alloy strips under furnace hot conditions using pinch rollers, S-roll groups, and jumping rollers, this paper utilizes the high density characteristic of copper alloy strips (density of 8.9 × 10⁻⁶). 3 kg / m 3 The method of controlling tensile stress by suspending the strip and relying on its own weight is simple in structure, low in investment cost, and can effectively improve the plate quality of copper alloy thin strips with a thickness of 0.03~0.5mm.

[0014] 2. By setting up simple upper and lower wrap angle deflector tension single rollers in the continuous heat treatment furnace, the previous complex structure devices such as special pinch rollers, S-roll groups, and jumping rollers are replaced, which is beneficial to production operation, maintenance and repair, and easy to replace.

[0015] 3. By controlling the upper and lower air exchange devices, the thermal tension of the copper alloy strip is controlled while reducing the residual stress during heat treatment. This reduces the number of processes, effectively utilizes waste heat from production, and helps reduce energy consumption and production costs.

[0016] 4. It can produce high-precision copper alloy strips with low residual stress and a plate quality of 1~3I that are urgently needed in the market, which is conducive to replacing imports and saving foreign exchange. Attached Figure Description

[0017] Figure 1 A schematic diagram of the furnace body and various external tension control devices before and after the furnace in existing continuous heat treatment furnace technology; Figure 2 This is a schematic diagram illustrating the airflow floating control of copper alloy strips within a continuous heat treatment furnace using existing technology. Figure 3 This is a schematic diagram of the structure of the present invention; Figure 4 This is a schematic diagram showing the operating state of the copper alloy strip of the present invention; Figure 5 This is a schematic diagram of the structure of the present invention.

[0018] In the figure: 1. Continuous heat treatment furnace body; 2. Upper wrap angle deflector tension single roller; 3. Lower wrap angle deflector tension single roller; 4. Upper air exchange device; 5. Lower air exchange device; 6. Shaft sleeve; 7. Mandrel. Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figure 3-5 This invention provides a technical solution: a device for improving the finished sheet shape of ultra-thin copper alloy strip, comprising a continuous heat treatment furnace body 1, a lower corner deflecting tension roller 3, and an upper corner deflecting tension roller 2. The lower corner deflecting tension roller 3 is rotatably mounted on the lower side of the outlet of the continuous heat treatment furnace body 1 and connected to an external drive mechanism, serving as the driving roller; the upper corner deflecting tension roller 2 is rotatably mounted on the upper side of the inlet of the continuous heat treatment furnace body 1, serving as the undriven driven roller. The copper alloy strip rotates under the combined action of its own weight and the lower corner deflecting tension roller 3, allowing the copper alloy strip outside the furnace to enter the continuous heat treatment furnace body 1. The self-weight of the copper alloy strip suspension section between the upper and lower corner deflecting tension rollers 2 and 3 forms a two-stage stepped tensile stress control during the heat treatment process, utilizing the high density characteristic of the copper alloy strip (density of 8.9 × 10⁻⁶). 3 kg / m 3The method of controlling tensile stress by suspending the strip and relying on its own weight is simple in structure, low in investment cost, and can effectively improve the plate quality of copper alloy thin strips with a thickness of 0.03~0.5mm.

[0021] Preferably, the double-sided wrap angle value ∠a ≤ 45° between the upper wrap angle biasing tension roller 2 and the copper alloy strip, and the double-sided wrap angle value ∠b ≤ 30° between the lower wrap angle biasing tension roller 3 and the copper alloy strip, with ∠a > ∠b, can prevent slippage between the copper alloy strip and the upper and lower wrap angle biasing tension rollers; the height difference h between the upper wrap angle biasing tension roller 2 and the lower wrap angle biasing tension roller 3 ranges from 800mm to 200mm; the horizontal distance L between the upper wrap angle biasing tension roller 2 and the lower wrap angle biasing tension roller 3 ranges from 4500mm to 6000mm. Thus, the value of the copper alloy strip's suspension curvature radius P should be able to achieve a first-stage large tensile stress range of 6~8kg / mm ​​based on the self-weight of the suspension section. 2 Furthermore, the tensile stress fluctuation value is ≤±1.5%; the second-stage small tensile stress range is 4~6 kg / mm. 2 And the tensile stress fluctuation value is ≤±1.5%.

[0022] The above-mentioned radius of curvature P satisfies the formula: S=2Parcsin(L / 2P)-h, in mm. Where: S-arc length, P-radius of curvature, L-horizontal distance between the upper and lower rollers, h-height difference between the upper and lower rollers.

[0023] Therefore, the weight of the suspended section of the copper alloy strip, G = S·B·t·ρ = [2Parcsin(L / 2P)-h]Btρ, is in kg. Where the density of the copper alloy ρ = 8.9 × 10⁻⁶ 3 kg / m 3 B - strip width, t - strip thickness.

[0024] Tensile stress σ = G / s = [2Parcsin(L / 2P)-h]Btρ / Bt = ρ[2Parcsin(L / 2P)-h] = 8.9 × 10 3 ×[2Parcsin(L / 2P)-h],unit kg / mm 2 .

[0025] In a preferred embodiment, the device further includes an upper air exchange device 4 and a lower air exchange device 5. The upper air exchange device 4 is uniformly arranged above the copper alloy strip suspension section inside the continuous heat treatment furnace body 1; the lower air exchange device 5 is uniformly arranged below the copper alloy strip suspension section inside the continuous heat treatment furnace body 1. Both the upper and lower air exchange devices are controlled by circulating fans with an installed power of 15kW and a speed of 1800rpm, thereby realizing continuous flow and circulation of the atmosphere inside the heat treatment furnace to meet the requirements of the rapid and homogenized heat treatment process of copper alloy strip. While reducing the residual stress of the copper alloy strip during heat treatment, the thermal tension of the strip is also controlled, reducing the number of processes, effectively utilizing production waste heat, and helping to reduce energy consumption and production costs.

[0026] More preferably, both the upper wrap angle biasing tension roller 2 and the lower wrap angle biasing tension roller 3 include a bushing 6 and a spindle 7, with the bushing 6 sleeved on the outer surface of the spindle 7.

[0027] The present invention also provides a method for improving the finished sheet shape of ultra-thin copper alloy strips, as follows: An upper-angle deflecting tension roller 2 is installed at the inlet side of the continuous heat treatment furnace body 1, and a lower-angle deflecting tension roller 3 is installed at the outlet side, forming a high-low roller arrangement structure. The roller diameter is Φ180mm, and the roller structure is a combination of an internal mandrel and an external roller sleeve. The surface finish of the roller sleeve is 1.6μm. The lower-angle deflecting tension roller 3 is the driving roller, driven by a 2.4kW motor with a speed of 1500rpm, thereby enabling the copper alloy strip with a certain wrap angle to move towards the outlet direction. The upper-angle deflecting tension roller 2 is a driven roller without a motor. It rotates under the dual action of the weight of the copper alloy strip with a certain wrap angle and the driving force of the lower-angle deflecting tension roller 3, thus enabling the copper alloy strip outside the furnace to enter the continuous heat treatment furnace body 1.

[0028] To prevent slippage between the copper alloy strip and the upper and lower wrap angle tension rollers, the wrap angle 'a' of the upper wrap angle tension roller and the copper alloy strip with a certain wrap angle relationship must meet the following requirements: ∠a≤45°; the wrap angle 'b' of the lower wrap angle tension roller and the copper alloy strip with a certain wrap angle relationship must meet the following requirements: ∠b≤30°, while ∠a>∠b.

[0029] The upper wrap angle deflecting tension single roller located on the inlet side and the lower wrap angle deflecting tension single roller located on the outlet side form a high-low roller arrangement structure, wherein the upper wrap angle deflecting tension single roller is higher than the lower wrap angle deflecting tension single roller, the height difference h between the upper and lower rollers satisfies 800mm≤h≤1200mm, and the horizontal distance L between the upper and lower rollers satisfies 4500mm≤L≤6000mm.

[0030] Because copper alloy strips have a high density (density of 8.9 × 10⁻⁶), 3 kg / m 3 The copper alloy strip is suspended between the upper corner deflecting tension roller 2 and the lower corner deflecting tension roller 3. The weight of the copper alloy itself creates a two-stage tension control system during the heat treatment process. This system consists of two stages: a first stage of high tension control at the inner contact point between the suspended copper alloy strip and the upper corner deflecting tension roller 2; and a second stage of low tension control at the inner contact point between the suspended copper alloy strip and the lower corner deflecting tension roller 3. Specifically, the first stage of high tension ranges from 6 to 8 kg / mm². 2 Furthermore, the tensile stress fluctuation value is ≤±1.5%; the second-stage small tensile stress range is 4~6 kg / mm. 2 And the tensile stress fluctuation value is ≤±1.5%.

[0031] To ensure the matching of the tension of the thin strip inside and outside the heat treatment furnace, the inlet tension range of 2~3 kg / mm ​​is controlled by the external inlet roller group at the contact point between the copper alloy thin strip on the inlet side of the continuous heat treatment furnace body 1 and the upper wrap angle deflector tension single roller 2. 2 The outlet tension stress ranges from 2.5 to 4.5 kg / mm², formed at the outer contact point between the copper alloy strip on the outlet side of the continuous heat treatment furnace body 1 and the lower wrap angle deflector tension roller 3. This is achieved by utilizing the external outlet roller group to control the tension at the contact point. 2 The stress fluctuation value is controlled to be ≤±5%.

[0032] To ensure gravity control of the copper alloy strip under complete freedom, an upper air exchange device 4 located on the upper side of the continuous heat treatment furnace body 1 generates a downward buoyancy force on the copper alloy strip suspension section, while a lower air exchange device 5 located on the lower side of the continuous heat treatment furnace body 1 generates an upward buoyancy force on the copper alloy strip suspension section. The relationship between the upward and downward buoyancy forces and the strip's own weight satisfies F... 向上浮力 =(F 向下浮力 +The weight of the suspension thin strip).

[0033] Both the upper and lower air exchange devices are controlled by circulating fans with an installed power of 15kW and a speed of 1800rpm, thereby realizing continuous flow and circulation of the atmosphere in the heat treatment furnace to meet the requirements of the rapid and homogenized heat treatment process of copper alloy strips. While reducing the residual stress of copper alloy strips during heat treatment, the thermal tension of the strips is also controlled, reducing the number of processes, effectively utilizing production waste heat, and helping to reduce energy consumption and production costs.

[0034] The running speed of the copper alloy strip between the upper and lower wrap angle tension rollers should meet the following requirements: 60 m / min for strip thicknesses of 0.03~0.05 mm; 45 m / min for strip thicknesses of 0.05~0.08 mm; 30 m / min for strip thicknesses of 0.08~0.15 mm; and 5~15 m / min for strip thicknesses greater than 0.15 mm. To prevent slippage between the copper alloy strip and the upper and lower wrap angle tension rollers, which could lead to surface defects, the accuracy error of the above running speeds should be less than 0.15% of the set speed value.

[0035] All parts not disclosed in this invention are prior art, and their specific structures, materials, and working principles will not be described in detail. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

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