Advanced copper plate strip continuous rolling process

Abstract

The invention relates to the technical field of copper plate strip machining, and provides an advanced copper plate strip continuous rolling technology which comprises the steps that S1, a copper ingot with the copper content of 99.9% or above is selected, and raw materials are obtained through saw cutting and surface polishing; s2, the treated copper ingot is heated in a heating furnace, and the internal temperature uniformity of the copper ingot is guaranteed; s3, a roughing mill is used for rolling the heated copper ingot, and rough rolling is conducted for 2-3 passes; s4, the copper strip subjected to rough rolling enters an intermediate rolling mill, and intermediate rolling passes are 3-5 times; s5, the copper plate strip subjected to intermediate rolling enters a finishing mill, and the finishing pass is 3-4 times; and S6, on-line cooling is conducted, specifically, the copper plate strip obtained after finish rolling enters an on-line cooling system immediately. Through early-stage accurate saw cutting and polishing treatment, the initial quality of the copper plate strip is guaranteed, smooth proceeding of subsequent rolling procedures is guaranteed, the multi-pass continuous rolling process of rough rolling, intermediate rolling and finish rolling is combined with online cooling, and through strict parameter control, the production efficiency is improved, the energy consumption is effectively reduced, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of copper plate and strip processing, and in particular to an advanced copper plate and strip continuous rolling process. Background Art

[0002] As an important basic material, copper strip is widely used in many fields such as electronics, electrical appliances, automobiles, and construction. With the rapid development of modern industry, the quality and performance requirements of copper strip are increasing day by day. For example, in the electronics industry, high-precision and high-performance copper strip is essential to ensure the stability and reliability of electronic products.

[0003] The selection of roller materials in traditional processes is not reasonable. The hardness, cylindricity and other parameters of the rollers cannot meet the requirements of high-precision rolling, resulting in difficulty in controlling the thickness accuracy of the copper strip during continuous rolling and low production efficiency. At the same time, the lubrication method during the rolling process is relatively backward, which increases the friction between the rollers and the copper strips, which not only affects the rolling efficiency, but also leads to poor product surface quality. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention provides an advanced copper plate and strip continuous rolling process, which solves the problem in the prior art that the pressing accuracy is difficult to control during the continuous rolling of copper plates and strips.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: an advanced copper strip continuous rolling process, comprising the following steps:

[0006] S1. Plate and strip blank preparation: select copper ingots with a copper content of more than 99.9%, and saw them to make the size of the copper ingot meet the requirements of subsequent processing. The sawing accuracy is controlled at ±0.5mm, and then the surface of the copper ingot is polished to a polishing roughness of Ra0.8-Ra1.6μm;

[0007] S2. Heating treatment: The treated copper ingot is heated in a heating furnace at a temperature range of 650°C-750°C and a heating rate of 30-50°C / hour to ensure uniform temperature inside the copper ingot;

[0008] S3. Rough rolling process: The heated copper ingot is rolled using a rough rolling mill, the roll diameter of the rough rolling mill is 800-1000mm, the rough rolling reduction rate is 20%-30%, the rolling speed is 30-50m / min, and after 2-3 passes of rough rolling, the thickness of the copper strip is reduced to 70%-80% of the original thickness;

[0009] S4. Intermediate rolling process: After rough rolling, the copper strip enters the intermediate rolling mill. The surface hardness of the intermediate rolling mill roll is HRC58-HRC62, the intermediate rolling reduction rate is 15%-25%, the rolling speed is increased to 50-70m / min, and the intermediate rolling pass is 3-5 times to further refine the copper strip structure;

[0010] S5. Finishing rolling process: the copper strip after intermediate rolling enters the finishing mill, the cylindricality error of the finishing mill roll is less than 0.002mm, the finishing reduction rate is 10%-20%, the rolling speed is 70-100m / min, the finishing pass is 3-4 times, and the copper strip with target thickness and precision is obtained, and the target thickness tolerance is controlled within ±0.02mm;

[0011] S6. Online cooling: The copper strip after fine rolling immediately enters the online cooling system. The cooling medium is emulsion with an emulsion concentration of 3%-5%. The temperature is controlled at 20℃-30℃ and the cooling rate is 50-100℃ / second, reducing the temperature of the copper strip to 50℃-80℃.

[0012] Preferably, the copper ingot after sawing in S1 is subjected to flaw detection by using an ultrasonic flaw detection method with a flaw detection frequency of 2-5 MHz and a detection sensitivity of φ2 mm flat-bottom hole, to ensure that there are no obvious defects inside the copper ingot.

[0013] Preferably, the atmosphere in the heating furnace in S2 is a mixed gas of inert gas and hydrogen, wherein the inert gas accounts for 90%-95% and the hydrogen accounts for 5%-10%.

[0014] Preferably, the rollers of the rough rolling mill in S3 are made of high nickel, chromium, and molybdenum infinitely chilled cast iron, with a nickel content of 3%-5%, a chromium content of 1.5%-2.5%, and a molybdenum content of 0.2%-0.5%.

[0015] Preferably, tension rollers are provided at the inlet and outlet of the intermediate rolling mill, respectively, the inlet tension is 5-8 kN, and the outlet tension is 8-12 kN.

[0016] Preferably, the rollers of the finishing mill are lubricated with nano-scale graphite lubricant, the graphite particles have a particle size of 50-100 nm, and the lubricant is supplied at a rate of 5-10 ml / min.

[0017] Preferably, the emulsion in S6 is sprayed in the form of aerosol spray, the distance between the nozzle and the copper strip is 20-30 cm, and the spray angle is 30°-60°.

[0018] Preferably, the cooled copper strip is subjected to surface treatment, wherein the surface treatment comprises pickling and passivation, wherein the pickling adopts a nitric acid solution with a concentration of 8%-12% for 3-5 minutes, and the passivation adopts a chromate passivation solution for 2-3 minutes, so as to form a protective film on the surface of the copper strip.

[0019] The present invention provides an advanced copper strip continuous rolling process, which has the following beneficial effects:

[0020] 1. The present invention ensures the initial quality of the copper strip by precisely controlling the sawing accuracy, surface grinding roughness and heating temperature uniformity, and ensures the smooth progress of the subsequent rolling process. The multi-pass continuous rolling process of rough rolling, intermediate rolling and finishing rolling is combined with online cooling. Through strict parameter control, it not only improves the production efficiency, but also effectively reduces energy consumption and reduces production costs.

[0021] 2. The present invention innovatively adopts a mixed atmosphere of inert gas and hydrogen in the heating treatment step, which effectively prevents the oxidation of copper ingots at high temperatures and ensures the purity of the material. At the same time, the selection of the roll material and lubrication method of the rough rolling mill and the finishing rolling mill further improves the rolling efficiency and product quality. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Embodiment 1:

[0024] The embodiment of the present invention provides an advanced copper strip continuous rolling process, comprising the following steps:

[0025] S1. Select a copper ingot with a copper content of 99.95%, and use a high-precision sawing machine to saw it. The sawing accuracy is controlled at ±0.5mm. The size of the copper ingot after sawing meets the feeding requirements of the subsequent rough rolling mill. Subsequently, the surface of the copper ingot is polished using a grinding equipment, and the roughness after grinding reaches Ra1.2μm. Next, an ultrasonic flaw detector is used to perform flaw detection on the copper ingot after sawing. The flaw detection frequency is set to 3MHz, and the detection sensitivity is φ2mm flat-bottom hole. After detection, there are no obvious defects inside the copper ingot. The high-quality copper ingot and precise size control reduce stress concentration during the rolling process and reduce the possibility of defects such as cracks in the copper plate and strip. Accurate flaw detection can prevent copper ingots with internal problems from entering subsequent processing, thereby reducing the scrap rate and improving production efficiency and economic benefits;

[0026] S2. The treated copper ingot is placed in a heating furnace, which is filled with a mixed gas of 92% inert gas and 8% hydrogen, and the copper ingot is heated from room temperature to 700°C at a heating rate of 40°C / hour. During this process, the temperature uniformity inside the copper ingot is ensured by a temperature sensor and a control system, and the temperature fluctuation range is within the allowable value. The appropriate heating atmosphere and heating rate as well as precise temperature control are helpful to maintain the good performance of the copper ingot, prevent oxidation and internal structural defects, reduce surface defects caused by oxide scale and mechanical property fluctuations caused by internal structural unevenness, and improve product consistency and quality stability;

[0027] S3. The heated copper ingot is rolled using a rough rolling mill with a roller diameter of 900 mm. The rollers of the rough rolling mill are made of high nickel-chromium-molybdenum infinitely cold hardened cast iron, wherein the nickel content is 4%, the chromium content is 2%, and the molybdenum content is 0.3%. The rough rolling reduction rate is 25%, and the rolling speed is 40 m / min. After three passes of rough rolling, the thickness of the copper strip is reduced to 75% of the original thickness. The copper material can be uniformly deformed during the rolling process by rolling with multiple passes and appropriate reduction rates, thereby avoiding material rupture or internal stress concentration caused by excessive single reduction;

[0028] S4. After rough rolling, the copper strip enters the intermediate rolling mill, and the surface hardness of the intermediate rolling mill roll is HRC60. Tension rollers are set at the entrance and exit of the intermediate rolling mill, with an entrance tension of 6kN and an exit tension of 10kN. The intermediate rolling reduction rate is 20%, the rolling speed is increased to 60m / min, and the intermediate rolling passes are 4 times, which further refines the copper strip structure. The appropriate hardness of the roll and the reasonable tension setting can ensure the stability of the intermediate rolling process and the product quality, and reduce the shape defects of the copper strip during the rolling process, such as wavy or side bending. The optimized reduction rate, rolling speed and pass can further refine the copper strip structure, improve its flatness and dimensional accuracy, and make the copper strip closer to the requirements of the final product.

[0029] S5. The copper strip after intermediate rolling enters the finishing mill, and the cylindricity error of the finishing mill roll is 0.0015mm. The finishing mill roll lubrication adopts nano-graphite lubricant, the graphite particle size is 80nm, and the lubricant supply is 8ml / min. The finishing rolling reduction rate is 15%, the rolling speed is 80m / min, and the finishing passes are 3 times to obtain the copper strip with target thickness and precision. The target thickness tolerance is controlled within ±0.02mm. The use of high-precision roller cylindricity and nano-graphite lubricant can significantly improve the quality of the finished rolled products. The uniform pressure distribution reduces the thickness deviation. The good lubrication effect reduces the friction between the roller and the copper strip, reduces the possibility of roller wear and scratches on the surface of the copper strip, and improves the surface finish and dimensional accuracy of the copper strip, making it suitable for applications with high precision requirements.

[0030] S6. After finishing rolling, the copper strip immediately enters the online cooling system. The cooling medium is emulsion, the concentration of emulsion is 4%, and the temperature is controlled at 25°C. The emulsion is sprayed in aerosol spraying mode. The distance between the nozzle and the copper strip is 25cm, the spray angle is 45°, and the cooling rate is 80°C / second. The temperature of the copper strip is reduced to 65°C. Uniform cooling can avoid deformation of the copper strip due to local temperature differences, improve the flatness and dimensional stability of the product, and ensure that the product quality meets the requirements.

[0031] Embodiment 2:

[0032] The embodiment of the present invention provides an advanced copper strip continuous rolling process, comprising the following steps:

[0033] S1. Select a copper ingot with a copper content of 99.98%, and cut it through sawing. The sawing accuracy is strictly controlled at ±0.5mm. Then, the surface of the copper ingot is carefully polished to a roughness of Ra0.8μm. The sawed copper ingot is subjected to ultrasonic flaw detection. The flaw detection frequency is set to 5MHz and the detection sensitivity is φ2mm flat-bottom hole. After confirming that there are no defects inside the copper ingot, prepare for the next step of processing.

[0034] S2. Place the copper ingot in a heating furnace, the atmosphere in the heating furnace is a mixed gas composed of 95% inert gas and 5% hydrogen. Heat the copper ingot to 650℃ at a heating rate of 30℃ / hour to ensure that the temperature inside the copper ingot is uniform and the temperature deviation is within the allowable range.

[0035] S3. The heated copper ingots are rolled using a rough rolling mill with a roll diameter of 800 mm. The rough rolling mill rolls are made of high nickel, chromium, molybdenum infinitely cold-hardened cast iron with a nickel content of 3%, a chromium content of 1.5%, and a molybdenum content of 0.2%. The rough rolling reduction rate is 20%, and the rolling speed is 30 m / min. After two passes of rough rolling, the thickness of the copper strip is reduced to 70% of the original thickness.

[0036] S4. After rough rolling, the copper strip enters the intermediate rolling mill, and the surface hardness of the intermediate rolling mill roll is HRC58. Tension rollers are set at the entrance and exit of the intermediate rolling mill, with an entrance tension of 5kN and an exit tension of 8kN. The intermediate rolling reduction rate is 15%, the rolling speed is 50m / min, and the intermediate rolling passes are 3 times to refine the copper strip structure.

[0037] S5. After intermediate rolling, the copper strip enters the finishing mill, and the cylindricality error of the finishing mill roll is less than 0.002mm. The finishing mill roll lubrication adopts nano-graphite lubricant, the graphite particle size is 50nm, and the lubricant supply is 5ml / min. The finishing rolling reduction rate is 10%, the rolling speed is 70m / min, and the finishing rolling pass is 3 times, so that the copper strip reaches the target thickness and precision, and the thickness tolerance is within ±0.02mm.

[0038] S6. After finishing rolling, the copper strip enters the online cooling system. The cooling medium is an emulsion with a concentration of 3% and a temperature of 20°C. The emulsion is sprayed in an aerosol manner, with the nozzle 20 cm away from the copper strip, the spray angle 30°, and the cooling rate 50°C / second, reducing the temperature of the copper strip to 50°C.

[0039] S7. The copper strip after cooling is subjected to surface treatment. The pickling is carried out with a nitric acid solution of 8% for 3 minutes, and the passivation is carried out with a chromate passivation solution for 2 minutes. A protective film is formed on the surface of the copper strip. The pickling and passivation treatment can significantly improve the surface quality and corrosion resistance of the copper strip. The copper strip after removing surface impurities is more in line with the requirements of high-quality products in terms of appearance and performance, and the formation of the passivation film can extend the service life of the copper strip, so that it can maintain good performance under different environmental conditions, and broaden the application range of the copper strip.

[0040] To sum up, the continuous rolling process in the embodiment of the present invention is closely coordinated in all links, and through precise parameter control and advanced process means, the production efficiency, product quality and performance of copper plates and strips are effectively improved, and high-precision and high-quality continuous rolling production of copper plates and strips can be achieved.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An advanced copper strip continuous rolling process, characterized in that: The following steps are involved: S1. Plate and strip blank preparation: select copper ingots with a copper content of more than 99.9%, and saw them to make the size of the copper ingot meet the requirements of subsequent processing. The sawing accuracy is controlled at ±0.5mm, and then the surface of the copper ingot is polished to a polishing roughness of Ra0.8-Ra1.6μm; S2. Heating treatment: The treated copper ingot is heated in a heating furnace at a temperature range of 650°C-750°C and a heating rate of 30-50°C / hour to ensure uniform temperature inside the copper ingot; S3. Rough rolling process: The heated copper ingot is rolled using a rough rolling mill, the roll diameter of the rough rolling mill is 800-1000mm, the rough rolling reduction rate is 20%-30%, the rolling speed is 30-50m / min, and after 2-3 passes of rough rolling, the thickness of the copper strip is reduced to 70%-80% of the original thickness; S4. Intermediate rolling process: After rough rolling, the copper strip enters the intermediate rolling mill. The surface hardness of the intermediate rolling mill roll is HRC58-HRC62, the intermediate rolling reduction rate is 15%-25%, the rolling speed is increased to 50-70m / min, and the intermediate rolling pass is 3-5 times to further refine the copper strip structure; S5. Finishing rolling process: the copper strip after intermediate rolling enters the finishing mill, the cylindricality error of the finishing mill roll is less than 0.002mm, the finishing reduction rate is 10%-20%, the rolling speed is 70-100m / min, the finishing pass is 3-4 times, and the copper strip with target thickness and precision is obtained, and the target thickness tolerance is controlled within ±0.02mm; S6. Online cooling: The copper strip after fine rolling immediately enters the online cooling system. The cooling medium is emulsion with an emulsion concentration of 3%-5%. The temperature is controlled at 20℃-30℃ and the cooling rate is 50-100℃ / second, reducing the temperature of the copper strip to 50℃-80℃.

2. The advanced copper strip continuous rolling process according to claim 1, characterized in that: The copper ingot after sawing in S1 is subjected to flaw detection by using an ultrasonic flaw detection method with a flaw detection frequency of 2-5 MHz and a detection sensitivity of a φ2mm flat-bottom hole to ensure that there are no obvious defects inside the copper ingot.

3. The advanced copper strip continuous rolling process according to claim 1, characterized in that: The atmosphere in the heating furnace in S2 is a mixed gas of inert gas and hydrogen, wherein the inert gas accounts for 90%-95% and the hydrogen accounts for 5%-10%.

4. The advanced copper strip continuous rolling process according to claim 1, characterized in that: The rollers of the S3 medium rough rolling mill are made of high nickel, chromium, and molybdenum infinitely chilled cast iron, with a nickel content of 3%-5%, a chromium content of 1.5%-2.5%, and a molybdenum content of 0.2%-0.5%.

5. The advanced copper strip continuous rolling process according to claim 1, characterized in that: Tension rollers are respectively arranged at the inlet and outlet of the intermediate rolling mill, the inlet tension is 5-8 kN, and the outlet tension is 8-12 kN.

6. The advanced copper strip continuous rolling process according to claim 1, characterized in that: The rollers of the finishing mill are lubricated with nano-graphite lubricant, the diameter of the graphite particles is 50-100nm, and the supply amount of the lubricant is 5-10ml / min.

7. The advanced copper strip continuous rolling process according to claim 1, characterized in that: The spraying mode of the emulsion in S6 is aerosol spraying, the distance between the nozzle and the copper strip is 20-30 cm, and the spraying angle is 30°-60°.

8. The advanced copper strip continuous rolling process according to claim 1, characterized in that: The method also includes surface treatment of the cooled copper strip, wherein the surface treatment includes pickling and passivation, wherein the pickling adopts a nitric acid solution with a concentration of 8%-12% for 3-5 minutes, and the passivation adopts a chromate passivation solution for 2-3 minutes to form a protective film on the surface of the copper strip.