Process method for refining crystal grains of oxygen-free copper plate

Abstract

The invention discloses a technological method for refining oxygen-free copper plate crystal grains. The technological method comprises the following steps that an electrolytic copper plate is placed in a furnace bin to be melted, the surface of the electrolytic copper plate is covered with charcoal, semi-continuous casting billet drawing is carried out, and an oxygen-free copper cast ingot is produced; the oxygen-free copper casting blank is put into a heat preservation furnace to be preheated, the preheating temperature ranges from 800 DEG C to 900 DEG C, and the heat preservation time ranges from 2 hours to 3 hours; the preheated cast ingot is subjected to upsetting and drawing, the upsetting deformation is 50%-60%, the cast ingot is drawn to 150%-160% of the original cast ingot, and the upsetting and drawing times are 3-4 times; warm forging and square drawing are started, the warm forging temperature ranges from 700 DEG C to 750 DEG C, the cast ingot is upset to 50%-60% of the original length, square drawing is conducted to the needed blank length, and the final forging temperature is kept to be larger than or equal to 700 DEG C; the blank is cooled to the room temperature, cold forging is started, multiple passes of cold forging are conducted, the rolling reduction of each pass is 10%-15%, and the final cold forging deformation is 30%-60%; and the oxygen-free copper blank obtained after cold forging is subjected to aging heat treatment, the aging heat treatment temperature ranges from 350 DEG C to 450 DEG C, the aging heat treatment time ranges from 1 h to 2 h, air cooling is conducted after annealing, and the oxygen-free copper plate is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of plate preparation, and in particular relates to a process method for refining crystal grains of an oxygen-free copper plate. Background Art

[0002] Oxygen-free copper materials are widely used in the fields of electricity and electronics due to their high electrical and thermal conductivity. When used in particle accelerators or sputtering targets, grain growth is very likely to occur during the heat treatment process after plastic deformation. Thermal processing causes the grain size of the product to increase, which cannot effectively guarantee the quality of the plate. For example, the grain size of high-purity target materials is usually above 100μm, which seriously affects the subsequent performance. It has an adverse effect on the sputtering effect, or even a destructive effect. Therefore, it is necessary to control the grain size. Summary of the invention

[0003] The object of the present invention is to provide a process for refining the crystal grains of an oxygen-free copper plate, thereby solving at least part of the above-mentioned technical problems.

[0004] A first aspect of an embodiment of the present invention provides a process for refining the grains of an oxygen-free copper plate, comprising the following steps: Semi-continuous casting: The electrolytic copper plate is placed in the furnace for melting, the surface is covered with charcoal, and semi-continuous casting is performed to produce oxygen-free copper ingots; Preheating: Put the oxygen-free copper ingot into a holding furnace for preheating at a temperature of 800-900°C for 2-3 hours; Forging: The preheated ingot is subjected to upsetting and drawing, the upsetting deformation is 50%-60%, and the ingot is drawn to 150%-160% of the original ingot, and the number of upsetting and drawing is 3-4 times; Warm forging: Start warm forging and drawing, the warm forging temperature is 700-750℃, the ingot is roughened to 50%-60% of the original length, and drawn to the required billet length, and the final forging temperature is maintained ≥ 700℃; Cold forging: Cool the blank to room temperature and start cold forging. Cold forging is repeated for multiple times, with a reduction of 10%-15% in each pass. The final cold forging deformation is 30-60%; Annealing: The oxygen-free copper blank after cold forging is subjected to aging heat treatment at a temperature of 350-450°C for 1-2 hours. After annealing, air cooling is performed to obtain an oxygen-free copper sheet.

[0005] The technical effect achieved is: through a series of steps such as semi-continuous casting and drawing to produce oxygen-free copper ingots, preheating, forging, warm forging, cold forging and annealing, the grains of oxygen-free copper plates can be effectively refined. The heat treatment and deformation processes in these steps help to break the original grain structure and promote the formation and refinement of new grains; grain refinement can reduce the interface between grains, thereby reducing the scattering of electrons during conduction and improving the conductivity of the material. At the same time, grain refinement also helps to improve the thermal conductivity of the material, because the grain boundary can serve as a phonon scattering center to reduce the energy loss during heat conduction; the forging and cold forging steps can optimize the microstructure of the material and improve the strength and toughness of the material by controlling the amount and number of deformations. These steps help to form a uniform grain distribution and reduce defects in the material, thereby improving the overall mechanical properties; through the preheating and warm forging steps, it can ensure that the material maintains a stable microstructure at high temperature, reduce grain growth and phase change at high temperature, thereby maintaining the high temperature stability of the material; in the forging and cold forging process, by controlling the amount and number of deformations, the residual stress inside the material can be effectively controlled. The annealing step further releases these internal stresses, ensuring that the material will not suffer performance degradation or failure due to stress concentration during use; through the preheating and forging steps, the plasticity of the material can be improved, making it easier to deform during the subsequent cold forging process, reducing cracks and defects during processing; by accurately controlling the process parameters of continuous casting, preheating, forging, warm forging, cold forging and annealing, production efficiency can be improved, material waste can be reduced, and production costs can be reduced. According to the above-mentioned method for refining the grains of oxygen-free copper plates, not only can the hardness of the oxygen-free copper plates be effectively and accurately controlled, but also the internal stress inside them can be kept low, so that the grain size can be controlled within the range of 100μm, effectively improving the performance of the plates.

[0006] Optionally, the purity of the electrolytic copper plate is greater than 99.95%.

[0007] The technical effect achieved is: using electrolytic copper plates with a purity greater than 99.95% as raw materials ensures the high purity of the final oxygen-free copper plates, thereby improving their conductivity and corrosion resistance and reducing the negative impact of impurities on material properties.

[0008] Optionally, in the preheating step, the preheating temperature is 850° C. and the insulation time is 3 hours.

[0009] The technical effect achieved is: the preheating temperature is 850℃ and the holding time is 3 hours. This specific preheating condition helps to uniformize the temperature inside the copper ingot, provides a good starting condition for the subsequent forging process, and helps to uniformly refine the grains.

[0010] Optionally, in the forging step, the drawing deformation is 55%, and the drawing is extended to 155% of the original.

[0011] The technical effect achieved is: the upsetting deformation in the forging step is 55%, and the drawing is extended to 155% of the original. This specific deformation and drawing ratio helps to promote further grain refinement while maintaining the plasticity of the material and avoiding cracks during the forging process.

[0012] Optionally, in the warm forging step, the warm forging temperature is 730°C.

[0013] The technical effect achieved is: the warm forging temperature is 730℃. This temperature selection helps to reduce the resistance to thermal deformation during the forging process, while maintaining the plasticity of the material, which helps to uniformly refine the grains and optimize the material properties.

[0014] Optionally, in the cold forging step, the reduction in each pass is preferably 12%, and the final cold forging deformation is 40%.

[0015] The technical effect achieved is: the reduction in each cold forging step is 12%, and the final cold forging deformation is 40%. This gradually increasing cold forging deformation helps to further refine the grains, improve the strength and hardness of the material, and control the generation of internal stress.

[0016] Optionally, in the annealing step, the aging heat treatment temperature is preferably 400° C., and the aging heat treatment time is preferably 1.5 hours.

[0017] The technical effect achieved is: the aging heat treatment temperature in the annealing step is 400°C, and the aging heat treatment time is 1.5 hours. This specific annealing condition helps to release the internal stress generated during forging and cold forging, optimize the microstructure of the material, and improve the overall performance of the material.

[0018] Optionally, in the forging step, the preheated ingot is subjected to multiple upsetting and drawing, and water cooling is performed after each upsetting and drawing; In the cold forging step, a method of gradually increasing the deformation amount in multiple passes is adopted, and the final cold forging deformation amount is 40-50%.

[0019] The technical effects achieved are: multiple upsetting and water cooling are performed in the forging step, and the deformation is gradually increased in multiple passes in the cold forging step. These measures help to further refine the grains, improve the plasticity and toughness of the material, and reduce the accumulation of internal stress.

[0020] Optionally, in the annealing step, a two-stage annealing treatment is adopted, the first stage is 350-400° C., the duration is 0.5-1 hour, and the second stage is 400-450° C., the duration is 1-1.5 hours; After the annealing step is completed, rapid cooling to room temperature is performed.

[0021] The technical effect achieved is: a two-stage annealing treatment is adopted, the first stage is 350-400℃, and the second stage is 400-450℃. This staged annealing strategy helps to release internal stress more effectively, refine grains, and fix the grain size by rapid cooling to room temperature to prevent grain growth.

[0022] Optionally, in the semi-continuous casting step, the billet drawing speed is controlled to be 120-200 mm / min; and in the warm forging step, a protective atmosphere is used for forging.

[0023] The technical effects achieved are: controlling the billet drawing speed to 120-200 mm / min in the semi-continuous casting step helps ensure the uniformity of the ingot and the consistency of the microstructure; using a protective atmosphere for forging in the warm forging step helps prevent oxidation and contamination and ensure the purity and performance of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic flow chart of a process method for refining crystal grains of an oxygen-free copper plate according to an embodiment of the present invention; Figure 2 A metallographic structure diagram of a refined oxygen-free copper plate grain obtained in Example 1 of the present invention; Figure 3 This is a metallographic structure diagram of the refined oxygen-free copper plate grains obtained in Example 2 of the present invention. DETAILED DESCRIPTION

[0025] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The modes described in the following exemplary embodiments do not represent all modes consistent with the present invention. Instead, they are merely examples of devices consistent with some aspects of the present invention as detailed in the appended claims.

[0026] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present specification and claims do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantitative limitation, but indicate that there is at least one. If only "one" is referred to, it will be separately stated. "Multiple" or "several" means two or more. Unless otherwise specified, words such as "front", "rear", "lower" and / or "upper" are only for the convenience of explanation and are not limited to one position or one spatial orientation. Words such as "include" or "comprise" mean that the elements or objects appearing in front of "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. "Connected" or "connected" and similar words are not limited to physical or mechanical connections, and may include electrical connections, whether direct or indirect. The singular forms "a", "said" and "the" used in the present specification and the appended claims are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0027] like Figure 1 As shown, the present invention discloses a process method for refining the crystal grains of oxygen-free copper plates, and the specific steps thereof include: semi-continuous casting, preheating, forging, warm forging, cold forging and annealing.

[0028] The semi-continuous casting steps specifically include: placing the electrolytic copper plate in the furnace for melting, covering the surface with charcoal, and performing semi-continuous casting to produce oxygen-free copper ingots; wherein the purity of the electrolytic copper plate is greater than 99.95%. Using electrolytic copper plates with a purity greater than 99.95% as raw materials ensures the high purity of the final oxygen-free copper plate, thereby improving its conductivity and corrosion resistance and reducing the negative impact of impurities on material properties.

[0029] The preheating step specifically includes: placing the oxygen-free copper ingot into a holding furnace for preheating, the preheating temperature is 800-900°C, and the holding time is 2-3 hours; wherein the preheating temperature is preferably 850°, and the holding time is 3 hours. This specific preheating condition helps to homogenize the temperature inside the copper ingot, provides a good starting condition for the subsequent forging process, and helps to uniformly refine the grains.

[0030] The specific steps of warm forging include: starting warm forging and squaring, the warm forging temperature is 700-750℃, roughening the ingot to 50%-60% of the original length, squaring to the required billet length, and maintaining the final forging temperature ≧700℃; wherein the warm forging temperature is preferably 730℃; this temperature selection helps to reduce the resistance to thermal deformation during the forging process, while maintaining the plasticity of the material, which helps to uniformly refine the grains and optimize the material properties.

[0031] The specific steps of cold forging include: cooling the blank to room temperature, starting cold forging, cold forging multiple times, with a reduction of 10%-15% in each pass, and a final cold forging deformation of 30-60%; wherein, the reduction in each pass is preferably 12%, and the final cold forging deformation is 40%. This gradually increasing cold forging deformation helps to further refine the grains, improve the strength and hardness of the material, and control the generation of internal stress.

[0032] The specific steps of annealing include: subjecting the cold-forged oxygen-free copper blank to aging heat treatment at a temperature of 350-450°C for 1-2 hours, and air cooling after annealing to obtain an oxygen-free copper sheet. The aging heat treatment temperature is 400°C for 1.5 hours. This specific annealing condition helps to release the internal stress generated during forging and cold forging, optimize the microstructure of the material, and improve the overall performance of the material.

[0033] As an optional implementation: in the forging step, the preheated ingot is subjected to multiple upsetting and drawing, and water cooling is performed after each upsetting and drawing; in the cold forging step, the deformation is gradually increased by multiple passes, and the final cold forging deformation is 40-50%. Multiple upsetting and water cooling are performed after each upsetting and in the cold forging step, and multiple upsetting and deformation are gradually increased by multiple passes. These measures help to further refine the grains, improve the plasticity and toughness of the material, and reduce the accumulation of internal stress.

[0034] As an optional implementation: in the annealing step, a two-stage annealing treatment is adopted, the first stage is 350-400℃, the duration is 0.5-1 hour, and the second stage is 400-450℃, the duration is 1-1.5 hours; after the annealing step is completed, rapid cooling to room temperature is performed. The two-stage annealing treatment is adopted, the first stage is 350-400℃, and the second stage is 400-450℃. This staged annealing strategy helps to release internal stress more effectively, refine grains, and fix the grain size by rapid cooling to room temperature to prevent grain growth.

[0035] As an optional implementation: in the semi-continuous casting step, the billet drawing speed is controlled to be 120-200 mm / min; in the warm forging step, the forging is performed in a protective atmosphere. Controlling the billet drawing speed in the semi-continuous casting step to be 120-200 mm / min helps to ensure the uniformity of the ingot and the consistency of the microstructure; using a protective atmosphere for forging in the warm forging step helps to prevent oxidation and contamination and ensure the purity and performance of the material.

[0036] The grains of oxygen-free copper sheets can be effectively refined by a series of steps such as semi-continuous casting and drawing to produce oxygen-free copper ingots, preheating, forging, warm forging, cold forging and annealing. The heat treatment and deformation processes in these steps help to break the original grain structure and promote the formation and refinement of new grains; grain refinement can reduce the interface between grains, thereby reducing the scattering of electrons during conduction and improving the conductivity of the material. At the same time, grain refinement also helps to improve the thermal conductivity of the material, because the grain boundary can serve as a phonon scattering center to reduce the energy loss during heat conduction; the forging and cold forging steps can optimize the microstructure of the material and improve the strength and toughness of the material by controlling the amount and number of deformations. These steps help to form a uniform grain distribution and reduce defects in the material, thereby improving the overall mechanical properties; through the preheating and warm forging steps, it can ensure that the material maintains a stable microstructure at high temperature, reduce grain growth and phase change at high temperature, and thus maintain the high temperature stability of the material; in the forging and cold forging process, by controlling the amount and number of deformations, the residual stress inside the material can be effectively controlled. The annealing step further releases these internal stresses, ensuring that the material will not suffer performance degradation or failure due to stress concentration during use; through the preheating and forging steps, the plasticity of the material can be improved, making it easier to deform during the subsequent cold forging process, reducing cracks and defects during processing; by accurately controlling the process parameters of continuous casting, preheating, forging, warm forging, cold forging and annealing, production efficiency can be improved, material waste can be reduced, and production costs can be reduced. According to the above-mentioned method for refining the grains of oxygen-free copper plates, not only can the hardness of the oxygen-free copper plates be effectively and accurately controlled, but also the internal stress inside them can be kept low, so that the grain size can be controlled within the range of 100μm, effectively improving the performance of the plates. Example

[0037] The semi-continuously cast copper ingot is placed in a resistance heating furnace for heating, and the copper ingot is preheated to 850°C for 3 hours to make the internal temperature of the copper ingot uniform. The preheated copper ingot is then forged for 4 times, with a deformation of 50% each time, and cooled after forging. The forged copper ingot is warm forged and drawn, the warm forging temperature is 750℃, the final forging temperature should be greater than 700℃, and it is cooled after forging; The cooled copper ingot is cold forged, and the cold forging deformation is 60% of the original thickness of the copper ingot; The cold forged copper plate is annealed at a temperature of 450°C for 1 h, and air-cooled after annealing.

[0038] The obtained copper plate grain size is as follows: Figure 2 As shown, it is approximately 40-50μm. Example

[0039] The copper ingot is placed in a resistance heating furnace for heating. The copper ingot is preheated to 850℃ and kept warm for 3 hours to make the internal temperature of the copper ingot uniform. Then the preheated copper ingot is forged for 4 times, with a deformation of 50% each time. The forged copper ingot is warm forged and drawn, the warm forging temperature is 750℃, the final forging temperature should be greater than 700℃, and it is cooled after forging; The cooled copper ingot is cold forged, and the cold forging deformation is 40% of the original thickness of the copper ingot; The cold forged copper plate was annealed at a temperature of 360°C for 1.5 h, and then air-cooled.

[0040] The obtained copper plate grain size is as follows: Figure 3 As shown, it is approximately 40-60μm.

[0041] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A process for refining the crystal grains of oxygen-free copper plate, characterized in that: The process comprises the following steps: Semi-continuous casting: The electrolytic copper plate is placed in the furnace for melting, the surface is covered with charcoal, and semi-continuous casting is performed to produce oxygen-free copper ingots; Preheating: Put the oxygen-free copper ingot into a holding furnace for preheating at a temperature of 800-900°C for 2-3 hours; Forging: The preheated ingot is subjected to upsetting and drawing, the upsetting deformation is 50%-60%, and the ingot is drawn to 150%-160% of the original ingot, and the number of upsetting and drawing is 3-4 times; Warm forging: Start warm forging and drawing, the warm forging temperature is 700-750℃, the ingot is roughened to 50%-60% of the original length, and drawn to the required billet length, and the final forging temperature is maintained ≥ 700℃; Cold forging: Cool the blank to room temperature and start cold forging. Cold forging is repeated for multiple times, with a reduction of 10%-15% in each pass. The final cold forging deformation is 30-60%; Annealing: The oxygen-free copper blank after cold forging is subjected to aging heat treatment at a temperature of 350-450°C for 1-2 hours. After annealing, air cooling is performed to obtain an oxygen-free copper sheet.

2. A process for refining the grains of oxygen-free copper sheet according to claim 1, characterized in that: The purity of the electrolytic copper plate is greater than 99.95%.

3. The process for refining the grain size of oxygen-free copper sheet according to claim 1, characterized in that: In the preheating step, the preheating temperature is 850° C. and the holding time is 3 hours.

4. The process for refining the crystal grains of oxygen-free copper sheet according to claim 1, characterized in that: In the forging step, the draw deformation is 55%, and the drawing length is 155% of the original.

5. The process for refining the grain size of oxygen-free copper sheet according to claim 1, characterized in that: In the warm forging step, the warm forging temperature is 730°C.

6. The process for refining the crystal grains of oxygen-free copper sheet according to claim 1, characterized in that: In the cold forging step, the reduction in each pass is 12%, and the final cold forging deformation is 40%.

7. The process for refining the crystal grains of oxygen-free copper sheet according to claim 1, characterized in that: In the annealing step, the aging heat treatment temperature is 400° C., and the aging heat treatment time is 1.5 hours.

8. The process for refining the grain size of oxygen-free copper sheet according to claim 1, characterized in that: In the forging step, the preheated ingot is subjected to multiple upsetting and drawing, and water cooling is performed after each upsetting and drawing; In the cold forging step, a method of gradually increasing the deformation amount in multiple passes is adopted, and the final cold forging deformation amount is 40-50%.

9. The process for refining the crystal grains of oxygen-free copper sheet according to claim 1, characterized in that: In the annealing step, a two-stage annealing treatment is adopted, the first stage is 350-400°C, the duration is 0.5-1 hour, and the second stage is 400-450°C, the duration is 1-1.5 hours; After the annealing step is completed, rapid cooling to room temperature is performed.

10. The process for refining the crystal grains of oxygen-free copper sheet according to claim 1, characterized in that: In the semi-continuous casting step, the billet drawing speed is controlled to be 120-200 mm / min; in the warm forging step, forging is performed in a protective atmosphere.

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