Preparation method of high-quality large-specification copper-nickel-tin alloy round cast ingot

Abstract

The invention discloses a preparation method of a high-quality large-specification copper-nickel-tin alloy round cast ingot. The preparation method comprises the following core preparation processes of burdening, smelting, refining, converter treatment, deoxidation and modification, electromagnetic stirring casting and homogenizing annealing. The ingredients are weighed according to target alloy components, the target alloy components comprise a copper plate raw material, a nickel plate raw material and a tin plate raw material, and the mass fraction of each element is controlled; s2, smelting: adding cathode copper and a nickel plate into a non-vacuum tipping type induction smelting furnace, starting to heat and melt, covering calcined charcoal in the melting process, and continuously starting an electromagnetic stirring device in the smelting process so as to fully stir a melt; s3, refining: after the smelting is finished, uniformly spraying a refining agent into a melt by using high-purity argon gas as a carrier, slagging off and covering charcoal after the refining is finished, and finally sampling in front of a furnace and adjusting components until the components are qualified; a specific refining agent and a specific refining process are adopted, inclusions and gas impurities in the melt can be efficiently removed, and the purity of the melt is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of copper-nickel-tin alloy ingot preparation technology, specifically relating to a method for preparing high-quality, large-size copper-nickel-tin alloy round ingots. Background Technology

[0002] Copper-nickel-tin alloys, as a highly promising non-ferrous metal material, have demonstrated significant advantages over copper-beryllium alloys in numerous fields. While copper-beryllium alloys possess excellent properties, beryllium is toxic and poses risks to the environment and human health during production and use. In contrast, copper-nickel-tin alloys not only exhibit good strength, hardness, corrosion resistance, and electrical conductivity, but are also environmentally friendly and non-toxic, making them an ideal alternative. However, existing copper-nickel-tin alloy ingot preparation technologies suffer from numerous defects, severely restricting their large-scale application and performance improvement. Specific problems include: 1. Severe compositional segregation: In traditional manufacturing processes, density differences among alloying elements and solute redistribution during solidification lead to uneven composition within the ingot, particularly significant segregation of Sn. This results in substantial performance variations across different parts of the ingot, reducing the overall quality and reliability of the material.

[0003] 2. Coarse grains: Existing processes struggle to effectively control grain growth, resulting in generally large ingot grain sizes. Coarse grains reduce the material's strength, toughness, and machinability, increasing the difficulty and cost of subsequent processing.

[0004] 3. Prone to cracking during processing: Due to compositional segregation and coarse grains, ingots are prone to cracking during processing, especially in the preparation of large-sized ingots. This problem is more prominent. Processing cracking not only reduces the product yield but also affects the material's performance and safety.

[0005] In summary, existing copper-nickel-tin alloy ingot preparation technologies cannot meet the production demands for high-quality, large-size ingots. There is an urgent need for a new preparation method to solve the above problems and improve the quality and performance of ingots. Summary of the Invention

[0006] To address the problems mentioned in the background art, the purpose of this invention is to provide a method for preparing high-quality, large-size copper-nickel-tin alloy round ingots. This method aims to solve prominent problems existing in the current preparation process of large-size copper-nickel-tin alloy ingots, such as severe compositional segregation, coarse grains, and susceptibility to cracking during processing. These problems result in poor ingot quality and unstable performance, making it difficult to meet the high-quality material requirements of high-end fields such as aerospace, electronic communications, and marine engineering.

[0007] The preparation method of this invention is expected to produce large-sized copper-nickel-tin alloy round ingots with a diameter ≥203mm, while controlling the Sn segregation rate to ≤6%, making the average grain size ≤500μm, and ensuring that the ingot is free from defects such as porosity, inclusions, and cracks, thus significantly improving the overall quality and performance of the ingot and meeting the stringent material requirements of various application fields. To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows: A method for preparing high-quality, large-size copper-nickel-tin alloy round ingots includes the following core preparation process: batching, smelting, refining, converter, deoxidation and modification, electromagnetic stirring casting, and homogenization annealing steps. S1, Batching: Weigh the ingredients according to the target alloy composition, which includes copper plate, nickel plate, and tin plate raw materials. Control the mass fraction of each element. The mass fraction of each element is as follows: Ni 12.0~16wt.%, Sn 7.0~9.0wt.%, Mn 0.10~0.50 wt.%, Fe 0.10~0.50 wt.%, Nb 0.05~0.20 wt.%, Zr 0.05~0.20 wt.%, Ti 0.05~0.10 wt.%, Mg 0.05~0.15 wt.%, with the balance being Cu and other unavoidable impurities. S2, Smelting: Cathode copper and nickel plates are added to a non-vacuum tilting induction melting furnace to start heating and melting. During the melting process, calcined charcoal is covered. During the smelting process, the electromagnetic stirring device is continuously turned on to fully stir the melt. S3, Refining: After smelting, high-purity argon is used as a carrier to evenly spray the refining agent into the melt. After refining, slag is removed, charcoal is used to cover the melt, and finally, samples are taken in front of the furnace to adjust the composition until it meets the requirements. S4, Converter: The melt in the smelting furnace is transferred to the holding furnace through the converter trough; during the converter process, a natural gas flame is continuously applied above the trough to protect the melt, and at the same time the melt is transferred to the holding furnace for refining. S5, Deoxidation and Modification: After the converter is completed, deoxidizer Mg is added to the holding furnace for deoxidation and degassing. Then, slag is removed, charcoal is covered, and finally the furnace is held and the temperature is adjusted to the casting temperature. In addition, modifier CuZr master alloy is added before casting. S6, Electromagnetic stirring casting: Before casting, the crystallizer and guide pipe are preheated. Then, the melt in the holding furnace is discharged through the guide pipe and directed into the electromagnetic stirring crystallizer. Covering agent is evenly added into the crystallizer by an automatic feeding device to protect the melt. During the casting process, refining agent is added to the holding furnace, and the discharge flow rate is adjusted in real time by an automatic control system. When the casting process reaches a stable state, the electromagnetic stirring system is turned on. S7, Homogenization Annealing: After the ingot casting is completed, the ingot is immediately transferred to a preheated homogenizing furnace for homogenization annealing. The preheating temperature is 300-500℃. The homogenization process is carried out in stages, with the temperature increased to 850℃ at a rate of 100-150℃, and held for 10-15 hours. Finally, it is air-cooled to room temperature to obtain the finished copper-nickel-tin ingot.

[0008] Furthermore, in the S1 batching step, the copper and nickel plates need to be pre-treated in a drying oven at a temperature of 100-300°C for 1-3 hours to remove surface moisture and impurities and ensure the quality of the batching.

[0009] Further specified, the thickness of the calcined charcoal covering in the smelting step of S2 is 30-60mm. After covering the calcined charcoal, the temperature is raised to 1150-1250℃ and tin ingot, CuMn master alloy, CuFe master alloy and NiNb master alloy are added. After the tin ingot melts, the temperature is raised to the smelting temperature of 1200-1350℃ and held for 20-60min. The power of the electromagnetic stirring device is 3-20KW.

[0010] Further specified, the purity of the high-purity argon gas in the refining step of S3 is ≥99.9996%, the temperature is controlled at 1200~1350℃ during the refining process, the refining time is 10~30min, the refining agent used is composed of 30~50% anhydrous sodium carbonate, 20~50% anhydrous borax, 2~10% fluorite and 2~10% cryolite, and the thickness of the charcoal is 30~50mm.

[0011] Further specifying, in the refining process of the holding furnace during the converter step of S4, Ar gas is introduced, and the Ar gas flow rate is 0.01~0.05m³. 3 / h, Ar gas pressure is 0.01~0.05MPa, continuous ventilation for 10~30min.

[0012] Further specifying that in the deoxidation and modification step of S5, the standing time is 20-40 minutes, the temperature is adjusted to the casting temperature of 1230-1280℃, and the modifier CuZr master alloy is added within 10-20 minutes before casting.

[0013] Further specified, the preheating time of the crystallizer and guide tube in the electromagnetic stirring casting of S6 is 20-50 min, and the preheating temperature is 300-500℃; the covering agent is carbon black and anhydrous borax, the refining agent is Cu-TiB2 alloy, the casting speed is 0.2-1.5 m / h, and the cooling water flow rate is 4-10 m³ / h. 3 / h, the power of the electromagnetic stirrer is 5-15KW.

[0014] Further specifying, the refining agent is a rod-shaped Cu-TiB2 alloy with a diameter of φ10mm.

[0015] Furthermore, the transfer time in the S7 homogenization annealing step shall not exceed 30 minutes.

[0016] Further specified, the finished copper-nickel-tin ingot has a diameter ≥203mm, a Sn element macroscopic segregation rate ≤6%, an average grain size ≤500μm, and the ingot is free of pores, inclusions, and cracks.

[0017] The beneficial effects of this invention are: This invention employs unique refining agents and processes to efficiently remove inclusions and gaseous impurities from the melt, significantly improving melt purity. By adding the modifying refining agents CuZr and Cu-TiB2 alloy to synergistically refine the grains, the internal grain structure of the ingot is significantly improved. Appropriate electromagnetic stirring, matched with casting speed and cooling water flow rate, effectively addresses compositional segregation during solidification and cooling of large-size copper-nickel-tin ingots, while simultaneously refining grain size, reducing defects such as porosity, looseness, and cracks, thus improving the internal quality of the ingot. Finally, a homogenization annealing process further improves macroscopic compositional segregation in the ingot, enabling the prepared large-size copper-nickel-tin ingots to meet the high-performance and high-reliability requirements of high-end fields such as aerospace and electronic communications.

[0018] In summary, the copper-nickel-tin alloy round ingot prepared by this invention has significant advantages. The Sn segregation rate is greatly reduced, from >10% in traditional processes to ≤6%, resulting in more uniform performance across the ingot and improved overall material reliability. The average grain size is reduced from >1000μm to ≤500μm, effectively improving the material's strength, toughness, and machinability. Attached Figure Description

[0019] The present invention can be further illustrated by the non-limiting embodiments given in the accompanying drawings; Figure 1 This is a schematic diagram of an embodiment of the method for preparing high-quality, large-size copper-nickel-tin alloy round ingots according to the present invention; Figure 2 This is a schematic diagram of an embodiment of the method for preparing high-quality, large-size copper-nickel-tin alloy round ingots according to the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments. The technical solutions in 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0022] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0023] like Figure 1 As shown, the present invention provides a method for preparing high-quality, large-size copper-nickel-tin alloy round ingots, which includes the following core preparation process: including batching, smelting, refining, converter, deoxidation and modification, electromagnetic stirring casting and homogenization annealing steps; S1, Batching: Weigh the ingredients according to the target alloy composition, which includes copper plate, nickel plate, and tin plate raw materials. Control the mass fraction of each element. The mass fraction of each element is as follows: Ni 12.0~16wt.%, Sn 7.0~9.0wt.%, Mn 0.10~0.50 wt.%, Fe 0.10~0.50 wt.%, Nb 0.05~0.20 wt.%, Zr 0.05~0.20 wt.%, Ti 0.05~0.10 wt.%, Mg 0.05~0.15 wt.%, with the balance being Cu and other unavoidable impurities. In the practical application of this embodiment, copper plates and nickel plates need to be pre-treated in a drying oven at a temperature of 100-300°C for 1-3 hours to remove surface moisture and impurities and ensure the quality of the ingredients.

[0024] S2, Smelting: Cathode copper and nickel plates are added to a non-vacuum tilting induction melting furnace to start heating and melting. During the melting process, calcined charcoal is covered. During the smelting process, the electromagnetic stirring device is continuously turned on to fully stir the melt. In the practical application of this embodiment, the thickness of the calcined charcoal covering in the smelting step is 30-60 mm. After covering the calcined charcoal, the temperature is raised to 1150-1250°C and tin ingots, CuMn master alloy, CuFe master alloy and NiNb master alloy are added. After the tin ingots melt, the temperature is raised to the smelting temperature of 1200-1350°C and held for 20-60 minutes. The power of the electromagnetic stirring device is 3-20 KW.

[0025] S3, Refining: After smelting, high-purity argon is used as a carrier to evenly spray the refining agent into the melt. After refining, slag is removed, charcoal is used to cover the melt, and finally, samples are taken in front of the furnace to adjust the composition until it meets the requirements. In the practical application of this embodiment, the purity of the high-purity argon gas in the refining step is ≥99.9996%, the temperature is controlled at 1200~1350℃ during the refining process, the refining time is 10~30min, the refining agent used is composed of 30~50% anhydrous sodium carbonate, 20~50% anhydrous borax, 2~10% fluorite and 2~10% cryolite, and the thickness of the charcoal is 30~50mm.

[0026] S4, Converter: The melt in the smelting furnace is transferred to the holding furnace through the converter trough; during the converter process, a natural gas flame is continuously applied above the trough to protect the melt, and at the same time the melt is transferred to the holding furnace for refining. In the practical application of this embodiment, Ar gas is introduced during the holding furnace refining process in the converter step, and the Ar gas flow rate is 0.01~0.05m³. 3 / h, Ar gas pressure is 0.01~0.05MPa, continuous ventilation for 10~30min.

[0027] S5, Deoxidation and Modification: After the converter is completed, deoxidizer Mg is added to the holding furnace for deoxidation and degassing. Then, slag is removed, charcoal is covered, and finally the furnace is held and the temperature is adjusted to the casting temperature. In addition, modifier CuZr master alloy is added before casting. In the practical application of this embodiment, in the deoxidation and modification steps, the standing time is 20-40 minutes, the temperature is adjusted to the casting temperature of 1230-1280℃, and the modifier CuZr master alloy is added within 10-20 minutes before casting.

[0028] S6, Electromagnetic stirring casting: Before casting, the crystallizer and guide pipe are preheated. Then, the melt in the holding furnace is discharged through the guide pipe and directed into the electromagnetic stirring crystallizer. In the crystallizer, a covering agent is evenly added to protect the melt through an automatic feeding device. During the casting process, a refining agent is added to the holding furnace through a wire feeding device, and the discharge flow rate is adjusted in real time through an automatic control system. When the casting process reaches a stable state, the electromagnetic stirring system is turned on. In the practical application of this embodiment, the preheating time of the crystallizer and guide tube in the electromagnetic stirring casting is 20-50 min, and the preheating temperature is 300-500℃; the covering agent is carbon black and anhydrous borax, the refining agent is φ10mm rod-shaped Cu-TiB2 alloy, the casting speed is 0.2-1.5 m / h, and the cooling water flow rate is 4-10 m³ / h. 3 / h, the power of the electromagnetic stirrer is 5-15KW.

[0029] S7, Homogenization Annealing: After the ingot casting is completed, the ingot is immediately transferred to a preheated homogenizing furnace for homogenization annealing. The preheating temperature is 300-500℃. The homogenization process is carried out in stages, with the temperature increased to 850℃ at a rate of 100-150℃, and held for 10-15 hours. Finally, it is air-cooled to room temperature to obtain the finished copper-nickel-tin ingot.

[0030] In the practical application of this embodiment, the transfer time in the homogenization annealing step does not exceed 30 minutes.

[0031] In the practical application of this embodiment, the finished copper-nickel-tin ingot has a diameter ≥203mm, a macroscopic segregation rate of Sn ≤6%, an average grain size ≤500μm, and the ingot is free of porosity, inclusions, and cracks.

[0032] The working principle of this invention is as follows: The core process of this invention has a unique mechanism of action, effectively solving problems in existing technologies. Electromagnetic stirring plays a crucial role in the casting process, generating a rotating magnetic field that forces convection in the melt. This convection promotes the uniform distribution of alloying elements and inhibits solute segregation, thereby significantly reducing the segregation rate of Sn. Simultaneously, convection also breaks up growing dendrites, increasing the number of crystal nuclei and refining the grain size.

[0033] Homogenization annealing is an important method for improving the composition distribution of ingots. At high temperatures, atoms have a high diffusion capacity. Through prolonged holding at high temperatures, alloying elements can diffuse fully, eliminating compositional segregation and making the composition inside the ingot more uniform. This not only improves the overall properties of the material but also enhances its machinability.

[0034] The auxiliary processes also have a synergistic effect. The modifier CuZr master alloy and the grain refiner Cu-TiB2 alloy can provide a large number of heterogeneous nuclei during solidification, promoting grain nucleation and thus refining the grains. These processes, combined with electromagnetic stirring and homogenization annealing, further improve the quality of the ingot. For example, refined grains can improve the strength and toughness of the material and reduce the risk of machining cracks; a uniform composition distribution ensures the stability and reliability of the material's properties.

[0035] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing high-quality, large-size copper-nickel-tin alloy round ingots, characterized in that, The core preparation process includes the following steps: batching, smelting, refining, converter, deoxidation and modification, electromagnetic stirring casting, and homogenization annealing. S1, Batching: Weigh the ingredients according to the target alloy composition, which includes copper plate, nickel plate, and tin plate raw materials. Control the mass fraction of each element. The mass fraction of each element is as follows: Ni 12.0~16wt.%, Sn 7.0~9.0wt.%, Mn 0.10~0.50wt.%, Fe 0.10~0.50 wt.%, Nb 0.05~0.20 wt.%, Zr 0.05~0.20 wt.%, Ti 0.05~0.10wt.%, Mg 0.05~0.15 wt.%, with the balance being Cu and other unavoidable impurities. S2, Smelting: Cathode copper and nickel plates are added to a non-vacuum tilting induction melting furnace to start heating and melting. During the melting process, calcined charcoal is covered. During the smelting process, the electromagnetic stirring device is continuously turned on to fully stir the melt. S3, Refining: After smelting, high-purity argon is used as a carrier to evenly spray the refining agent into the melt. After refining, slag is removed, charcoal is used to cover the melt, and finally, samples are taken in front of the furnace to adjust the composition until it meets the requirements. S4, Converter: The melt in the smelting furnace is transferred to the holding furnace through the converter trough; during the converter process, a natural gas flame is continuously applied above the trough to protect the melt, and at the same time the melt is transferred to the holding furnace for refining. S5, Deoxidation and Modification: After the converter is completed, deoxidizer Mg is added to the holding furnace for deoxidation and degassing. Then, slag is removed, charcoal is covered, and finally the furnace is held and the temperature is adjusted to the casting temperature. In addition, modifier CuZr master alloy is added before casting. S6, Electromagnetic stirring casting: Before casting, the crystallizer and the guide pipe are preheated. Then, the melt in the holding furnace is discharged through the guide pipe and led into the electromagnetic stirring crystallizer. The covering agent is evenly added in the crystallizer by the automatic feeding device to protect the melt. During the casting process, the refining agent is added to the holding furnace, and the discharge flow rate is adjusted in real time by the automatic control system. Once the casting process has reached a stable state, turn on the electromagnetic stirring system. S7, Homogenization Annealing: After the ingot casting is completed, the ingot is immediately transferred to a preheated homogenizing furnace for homogenization annealing. The preheating temperature is 300-500℃. The homogenization process is carried out in stages, with the temperature increased to 850℃ at a rate of 100-150℃, and held for 10-15 hours. Finally, it is air-cooled to room temperature to obtain the finished copper-nickel-tin ingot.

2. The method for preparing a high-quality, large-size copper-nickel-tin alloy round ingot according to claim 1, characterized in that: In the S1 batching step, the copper and nickel plates need to be pre-treated in a drying oven at a temperature of 100-300°C for 1-3 hours to remove surface moisture and impurities and ensure the quality of the batching.

3. The method for preparing a high-quality, large-size copper-nickel-tin alloy round ingot according to claim 1, characterized in that: In the smelting step of S2, the thickness of the calcined charcoal covering is 30-60 mm. After covering with calcined charcoal, the temperature is raised to 1150-1250°C and tin ingots, CuMn master alloy, CuFe master alloy and NiNb master alloy are added. After the tin ingots melt, the temperature is raised to the smelting temperature of 1200-1350°C and held for 20-60 minutes. The power of the electromagnetic stirring device is 3-20 KW.

4. The method for preparing a high-quality, large-size copper-nickel-tin alloy round ingot according to claim 1, characterized in that: The purity of the high-purity argon gas in the refining step of S3 is ≥99.9996%. The temperature is controlled at 1200-1350℃ during the refining process, and the refining time is 10-30 minutes. The refining agent used consists of 30-50% anhydrous sodium carbonate, 20-50% anhydrous borax, 2-10% fluorite, and 2-10% cryolite. The thickness of the charcoal is 30-50 mm.

5. The method for preparing a high-quality, large-size copper-nickel-tin alloy round ingot according to claim 1, characterized in that: During the heat preservation furnace refining process in the converter step of S4, Ar gas is introduced at a flow rate of 0.01–0.05 m³ / h and a pressure of 0.01–0.05 MPa for 10–30 min.

6. The method for preparing a high-quality, large-size copper-nickel-tin alloy round ingot according to claim 1, characterized in that: In the deoxidation and modification step of S5, the standing time is 20-40 minutes, the temperature is adjusted to the casting temperature of 1230-1280℃, and the modifier CuZr master alloy is added within 10-20 minutes before casting.

7. The method for preparing a high-quality, large-size copper-nickel-tin alloy round ingot according to claim 1, characterized in that: The preheating time for the crystallizer and guide tube in the electromagnetic stirring casting of S6 is 20–50 min, and the preheating temperature is 300–500 °C; the covering agent is carbon black and anhydrous borax, the refining agent is Cu-TiB2 alloy, the casting speed is 0.2–1.5 m / h, and the cooling water flow rate is 4–10 m³ / h. 3 / h, the power of the electromagnetic stirrer is 5-15KW.

8. The method for preparing a high-quality, large-size copper-nickel-tin alloy round ingot according to claim 7, characterized in that: The refining agent is a rod-shaped Cu-TiB2 alloy with a diameter of φ10mm.

9. The method for preparing a high-quality, large-size copper-nickel-tin alloy round ingot according to claim 1, characterized in that: The transfer time in the S7 homogenization annealing step shall not exceed 30 minutes.

10. The method for preparing a high-quality, large-size copper-nickel-tin alloy round ingot according to claim 1, characterized in that: The finished copper-nickel-tin ingots have a diameter ≥203mm, a macroscopic segregation rate of Sn ≤6%, an average grain size ≤500μm, and are free of porosity, inclusions, and cracks.

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