A high temperature homogenization annealing and quenching process for copper-nickel-tin alloys

Abstract

The application discloses a high-temperature homogenization annealing and quenching process and application of a copper-nickel-tin alloy, and the copper-nickel-tin alloy cast blank is heated at a speed of 80-120 DEG C / h, is kept warm for 2-5 hours when the temperature is raised to 450-550 DEG C, is kept warm for 8-10 hours when the temperature is raised to 750-820 DEG C, is kept warm for 13-16 hours when the temperature is raised to 850-900 DEG C, and then is furnace-cooled to below 750 DEG C and is discharged to be water-quenched, and the quenching temperature is 680-750 DEG C. The application solves the technical problems of traditional smelting and casting blank ingot dendritic segregation and high-temperature homogenization quenching cracking of the high-strength and high-elasticity copper-nickel-tin alloy, can greatly save manufacturing cost and improve production efficiency, and the copper-nickel-tin alloy cast blank is subjected to high-temperature homogenization and subsequent processing heat treatment, high-strength and high-elasticity copper-nickel-tin alloy strip and foil material with a thickness of 0.04-0.15 mm is obtained, and the material has higher strength, high elasticity and excellent wear resistance and corrosion resistance, and can meet the requirements of high-strength and high-elasticity electronic components in the aviation, aerospace, communication and electronic industries.

Description

Technical Field

[0001] This invention belongs to the field of copper-nickel-tin alloy production technology, specifically relating to a high-temperature homogenization annealing and quenching process and application for copper-nickel-tin alloys. Background Technology

[0002] Among the many copper alloys, precipitation-strengthened alloys are mainly beryllium bronze, whose excellent properties have led to its widespread use in manufacturing various signal switches, electrical connectors, plugs, relays, and other elastic components. However, in recent years, with the rapid development of the electronics and communications industry and the increasing demands for alloy performance in China, coupled with a strong environmental awareness, beryllium bronze is gradually being replaced by another high-strength, high-elasticity copper alloy, Cu-Ni-Sn alloy, due to the toxicity of its oxides or dust, low thermal stability, and poor high-temperature strain resistance.

[0003] Copper-nickel-tin alloy is a high-end copper alloy material with high strength, high elasticity, and excellent wear and corrosion resistance. In particular, the strength of Cu-15Ni-8Sn alloy can reach more than 1300MPa, which is comparable to high-strength steel and beryllium copper. Its corrosion resistance in seawater or acidic or oily / gas environments, as well as its wear resistance under high load conditions, are superior to beryllium copper and aluminum bronze. It can meet the needs of high-strength and high-elasticity electronic components used in aerospace, communications, and other industries.

[0004] Copper-nickel-tin alloys have extremely high nickel and tin content, and their melting points differ significantly. CuNi is an infinite solid solution, but Sn has extremely low solid solubility in the CuNi matrix at room temperature. Therefore, dendritic segregation easily occurs during alloy solidification. Sn aggregates through the interdendritic spaces, resulting in a highly uneven distribution of Sn. This leads to defects such as edge cracks and surface cracks during subsequent processing and heat treatment. Industrially, the billet needs to be gradient-heated and diffused at high temperatures for a long time to achieve Sn's solid solubility in the matrix. Rapid cooling then yields a supersaturated solid solution, resulting in a favorable processing structure.

[0005] After extensive industrial testing, the high-temperature homogenization quenching process of the alloy billet can eliminate dendritic segregation, but there are still serious problems: (1) it is very easy to cause edge cracking during rapid quenching; (2) the alloy is a precipitation hardening alloy, and the microstructure will undergo complex phase transformation during slow cooling or low-temperature quenching, precipitating hard and brittle cellular structures, which deteriorates the processing plasticity. This technical difficulty seriously reduces the product yield and may even lead to direct scrapping.

[0006] Currently, the high-temperature homogenization quenching process for Cu-Ni-Sn alloy billets is the core and key process in the overall process. This requires a high-strength and high-elasticity Cu-Ni-Sn alloy strip foil and a high-temperature homogenization quenching process to solve the technical problems of microstructure homogenization and high-temperature rapid quenching stress cracking, and improve the yield to meet the needs of current industrial development. These are technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0007] To address the issue that dendrite segregation is prone to occur during the solidification process of copper-nickel-tin alloys in existing technologies, leading to defects such as edge cracks and surface cracks during subsequent processing and heat treatment, this invention provides a high-temperature homogenization quenching process for high-strength and high-elasticity Cu-Ni-Sn alloy strips and foils. This process solves the technical problems of dendrite segregation and high-temperature homogenization quenching cracking in traditional melting and casting of high-strength and high-elasticity Cu-Ni-Sn alloy ingots, and can greatly save manufacturing costs and improve production efficiency.

[0008] This invention is achieved through the following technical solution: A high-temperature homogenization annealing and quenching process for copper-nickel-tin alloy involves heating the copper-nickel-tin alloy billet at a rate of 80-120℃ / h, holding it at 450-550℃ for 2-5 hours, holding it at 750-820℃ for 8-10 hours, holding it at 850-900℃ for 13-16 hours, then furnace cooling to below 750℃ and water quenching at a quenching temperature of 680-750℃.

[0009] Furthermore, the high-temperature homogenization annealing process involves heating the copper-nickel-tin alloy billet to 500℃ and holding it for 2-5 hours, heating it to 800℃ and holding it for 8-10 hours, and heating it to 880℃ and holding it for 15 hours.

[0010] Furthermore, the composition ratio of the copper-nickel-tin alloy billet is: 2% to 21% Ni, 3% to 9% Sn, 0.1% to 0.5% Zn, 0.1% to 0.5% Mn, 0.05% to 0.1% P, with the balance being Cu and unavoidable impurities; the percentage content is by weight.

[0011] Furthermore, the composition ratio of the copper-nickel-tin alloy billet is: 14~16% Ni, 7~9% Sn, 0.2~0.5% Mn, 0.1~0.3% Zn, 0.05%~0.1% P, with the remainder being copper and impurities less than 0.2%; or 19~21% Ni, 4~6% Sn, 0.2~0.5% Mn, 0.1~0.3% Zn, not more than 0.5% Fe, with the remainder being copper and impurities less than 0.2%.

[0012] Furthermore, nitrogen protection is provided during the annealing process.

[0013] Furthermore, the annealing and rapid quenching are performed using a bogie-type furnace.

[0014] Furthermore, the copper-nickel-tin alloy billet is a horizontally continuously cast billet with a thickness of 10-18 mm and a width of 400-700 mm.

[0015] Furthermore, the copper-nickel-tin alloy is used to prepare copper-nickel-tin alloy strips and foils with a thickness of 0.04-0.15 mm.

[0016] The beneficial effects achieved by this invention are as follows: (1) The present invention also provides a high-temperature homogenization annealing and quenching process for high-strength and high-elasticity copper-nickel-tin alloy under a specific ratio formulation, which solves the technical problems of dendrite segregation and high-temperature homogenization quenching cracking of traditional smelting and casting billets of high-strength and high-elasticity copper-nickel-tin alloy, and can greatly save manufacturing costs and improve production efficiency.

[0017] (2) The alloy casting billet in this invention is homogenized at high temperature and then processed and heat-treated to obtain a high-strength and high-elasticity copper-nickel-tin alloy strip and foil with a thickness of 0.04-0.15mm. This product has high strength, high elasticity and excellent wear and corrosion resistance, which can meet the needs of high-strength and high-elasticity electronic components in aerospace, communication electronics and other industries. Attached Figure Description

[0018] Figure 1 This is a dendritic structure diagram of the copper-nickel-tin alloy cast billet in Example 1; Figure 2 This is a diagram of the homogenized microstructure of the cast billet obtained after high-temperature homogenization quenching process. Figure 3 The billet after quenching in Example 1; Figure 4 The billet obtained by high-temperature homogenization annealing and quenching in Example 2; Figure 5 The blank after quenching in Comparative Example 1; Figure 6 This is a microstructure diagram of the copper-nickel-tin alloy billet after quenching, as shown in Comparative Example 2. Detailed Implementation

[0019] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention.

[0020] In the embodiments of this invention, the percentage content is the mass percentage content.

[0021] Example 1 Material selection: The composition of the copper-nickel-tin alloy billet is as follows: 14.8% Ni, 8.5% Sn, 0.35% Mn, 0.15% Zn, 0.1% P, with the remainder being copper and less than 0.2% impurities. The dendritic structure of the billet is as follows: Figure 1 The above; High-temperature homogenization annealing and quenching process for copper-nickel-tin alloys: (1) Equipment The copper-nickel-tin alloy billet is a horizontally continuously cast billet with a thickness of 14mm and a width of 450mm. It is subjected to high-temperature homogenization annealing in a bogie box furnace with nitrogen protection during the annealing process. (2) Process Annealing process: The copper-nickel-tin alloy billet is heated at a rate of 100℃ / h, held at 500℃ for 3 hours, then heated to 800℃ and held for 9 hours, then heated to 880℃ and held for 15 hours, then furnace cooled to 700℃ and water-quenched at 700℃. The billet remains intact during the quenching process. The homogeneous structure of the billet obtained by the high-temperature homogenization quenching process is as follows: Figure 2 As shown, no dendrite segregation problem was observed: the slab obtained after quenching is as follows. Figure 3 As shown, no cracks occurred at the edge after quenching; Example 2 Material selection: The composition ratio of copper-nickel-tin alloy billet is: 20% Ni, 5% Sn, 0.3% Mn, 0.2% Zn, 0.2% Fe, with the remainder being copper and less than 0.2% impurities; High-temperature homogenization annealing and quenching process for copper-nickel-tin alloys: (1) Equipment The alloy billet is a horizontally continuously cast billet with a thickness of 14mm and a width of 450mm. It is subjected to high-temperature homogenization annealing in a bogie box furnace with nitrogen protection during the annealing process. (2) Process: Annealing process: The copper-nickel-tin alloy billet is heated at a rate of 120℃ / h, held at 500℃ for 5 hours, then heated to 800℃ and held for 10 hours, followed by heating to 880℃ and holding for 15 hours. It is then furnace cooled to 650℃ and water-quenched at 650℃. During quenching, the billet remains intact without dendrite segregation. The resulting billet after quenching is as follows: Figure 4 As shown: Comparative Example 1 Material selection: The composition ratio of the copper-nickel-tin alloy billet is the same as that in Example 1: 14.8% Ni, 8.5% Sn, 0.35% Mn, 0.15% Zn, 0.1% P, with the remainder being copper and less than 0.2% impurities; High-temperature homogenization annealing and quenching process for copper-nickel-tin alloys: (1) Equipment The alloy billet is 14×450mm in size and is subjected to high-temperature homogenization annealing in a bogie box furnace with nitrogen protection during the annealing process. (2) Process Annealing process: The copper-nickel-tin alloy billet is heated at a rate of 100℃ / h, held at 500℃ for 3 hours, held at 800℃ for 9 hours, and held at 880℃ for 15 hours; the quenching temperature after exiting the furnace is 880℃. Cracking occurs during the quenching process, such as... Figure 5 As shown.

[0022] Comparative Example 2 Material selection: The composition ratio of the copper-nickel-tin alloy billet is the same as that in Example 1: 14.8% Ni, 8.5% Sn, 0.35% Mn, 0.15% Zn, 0.1% P, with the remainder being copper and less than 0.2% impurities; High-temperature homogenization annealing and quenching process for copper-nickel-tin alloys: (1) Equipment selection The alloy billet is 14×450mm in size and is subjected to high-temperature homogenization annealing in a bogie box furnace with nitrogen protection during the annealing process. (2) Process selection: Annealing process: The copper-nickel-tin alloy billet was heated at a rate of 100℃ / h, held at 800℃ for 9 hours, and then held at 880℃ for 5 hours. The billet was then quenched at 700℃. No cracking occurred during the quenching process. However, Sn segregation between the internal dendrites was not eliminated, causing edge cracking during subsequent rolling. Figure 6 As shown.

[0023] Comparative Example 3 Material selection: The composition ratio of the low-nickel tin-phosphorus bronze alloy casting billet is: 7.2% Sn, 0.1% Zn, 0.15% P, 0.1% Ni, with the remainder being copper and impurities less than 0.2%; The homogenization process involves bell-type furnace annealing at 780℃ for 7 hours in a high-hydrogen atmosphere with slow in-furnace cooling (no rapid quenching required). Compared to copper-nickel-tin alloys, tin-phosphorus bronze exhibits less segregation and a different strengthening mechanism, thus eliminating the need for rapid quenching. This highlights the unique characteristics of copper-nickel-tin alloys.

[0024] Using a high-strength, high-elasticity Cu-Ni-Sn alloy high-temperature homogenization quenching process as described in this invention patent, followed by subsequent processing and heat treatment, 0.04-0.15mm foil material (such as...) is obtained. Figure 6 As shown), tensile strength is 1250-1300MPa, elongation is 2.0-2.5%, and hardness is 390-410HV.

Claims

1. A high-temperature homogenization annealing and quenching process for copper-nickel-tin alloys, characterized in that, The copper-nickel-tin alloy billet is heated at a rate of 80-120℃ / h, held at 450-550℃ for 2-5 hours, held at 750-820℃ for 8-10 hours, and held at 850-900℃ for 13-16 hours. Then it is furnace cooled to below 750℃ and water-quenched at a temperature of 680-750℃. The composition ratio of the copper-nickel-tin alloy billet is: 2%~21%Ni, 3%~9%Sn, 0.1%~0.5%Zn, 0.1%~0.5%Mn, 0.05%~0.1%P, with the balance being Cu and unavoidable impurities; The percentage content mentioned is a weight percentage.

2. The high-temperature homogenization annealing and quenching process according to claim 1, characterized in that, The high-temperature homogenization annealing process involves heating the copper-nickel-tin alloy billet to 500℃ and holding it for 2-5 hours, heating it to 800℃ and holding it for 8-10 hours, and heating it to 880℃ and holding it for 15 hours.

3. The high-temperature homogenization annealing and quenching process according to claim 1, characterized in that, The composition of the copper-nickel-tin alloy billet is as follows: 14~16% Ni, 7~9% Sn, 0.2~0.5% Mn, 0.1~0.3% Zn, 0.05%~0.1% P, with the remainder being copper and impurities less than 0.2%.

4. The high-temperature homogenization annealing and quenching process according to claim 1, characterized in that, Nitrogen protection is applied during the annealing process.

5. The high-temperature homogenization annealing and quenching process according to claim 1, characterized in that, The annealing and rapid quenching are performed using a bogie-type furnace.

6. The high-temperature homogenization annealing and quenching process according to claim 1, characterized in that, The copper-nickel-tin alloy billet is a horizontally continuously cast billet with a thickness of 10-18 mm and a width of 400-700 mm.

7. The high-temperature homogenization annealing and quenching process according to claim 1, characterized in that, The copper-nickel-tin alloy is used to prepare copper-nickel-tin alloy strips and foils with a thickness of 0.04-0.15 mm.

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