Method for preparing beryllium-copper alloy through suspension smelting and continuous ingot pulling

Abstract

The invention provides a method for preparing beryllium-copper alloy by suspension smelting and continuous ingot pulling, which comprises the following steps of: preparing materials, drying raw materials, carrying out suspension smelting in a cold crucible, carrying out vacuum continuous ingot pulling, carrying out vacuum continuous charging and smelting, filling compressed air into a suspension smelting bin to atmospheric pressure after ingot pulling is finished, opening a furnace door, and controlling an ingot pulling head to rise to obtain a beryllium-copper alloy ingot; according to the beryllium-copper alloy ingot prepared through vacuum suspension smelting assisted vacuum continuous ingot pulling, the metal yield and the beryllium yield are larger than 98%.

Description

Technical Field

[0001] The present invention relates to the technical field of high-performance copper alloys and high-performance copper alloys for electronics, and in particular to a method for preparing beryllium copper alloy by adopting suspension smelting and continuous ingot drawing. Background Art

[0002] Beryllium copper alloy, as a typical representative of high-performance copper-based alloys, has the characteristics of high strength, high elasticity, excellent electrical and thermal conductivity, corrosion resistance and non-magnetic properties, becoming a key material in the fields of aerospace, new energy vehicles, high-end electronic devices, etc. At present, beryllium copper alloy ingots are produced by induction melting and semi-continuous casting. This production method requires the use of carbon materials such as soot and graphite flakes as surface covering agents in the casting process, which play a role in heat preservation, lubrication and air isolation during the casting process. However, the eddy currents in the casting process will cause the surface covering carbon material to be involved, which will lead to randomly distributed carbon inclusions in the beryllium copper alloy ingot, affecting the internal quality of the ingot, and causing defects such as rolling cracking during the processing deformation process. In addition, it will also affect the performance of beryllium copper products. At present, there is no process for preparing beryllium copper alloy ingots by carbon-free casting under vacuum conditions.

[0003] Most existing technologies use non-vacuum induction melting and semi-continuous casting methods to prepare beryllium copper alloy ingots. Under non-vacuum conditions, the burnout of metallic beryllium is large and the beryllium yield is low. Graphite flakes added during the smelting process will be drawn into the alloy liquid during the subsequent semi-continuous casting, causing carbon inclusions in the ingot, which is prone to cracking during the subsequent rolling process. The formation of the beryllium copper alloy ingot undergoes smelting, casting into a tundish, and then casting from the tundish into a crystallizer. The semi-continuous casting obtains the beryllium copper alloy ingot. The multiple transfers of the alloy liquid will flush the furnace body and the tundish, increasing the impurity content in the beryllium copper ingot. The smelting of the beryllium copper alloy takes a long time, and the standing time after smelting alone requires 20 to 30 minutes. The process consumes a lot of energy. The process uses argon bottom blowing and stirring, which has high requirements on the purity and dew point temperature of the argon.

[0004] The patent with application number 202210389957.4 uses non-vacuum induction melting, which has problems such as beryllium burnout and graphite flake entanglement, which will affect the subsequent processing of the ingot and thus affect the performance of beryllium copper products. Summary of the Invention

[0005] In view of the above drawbacks, the present invention proposes a method for preparing beryllium copper alloy by continuous ingot drawing using suspension smelting, comprising the following steps: S1: Prepare the ingredients and divide them into 3 to 6 portions for later use; S2: Drying the raw materials; S3: Cold crucible suspension melting After the first batch of raw materials is loaded into the crucible of the vacuum suspension melting furnace, the melting chamber is closed; the vacuum is pumped to no more than 6.67×10 -3 Pa, after the protective gas is filled to 0.04MPa, gradient temperature rise smelting is carried out; S4: Vacuum continuous ingot pulling Reduce the refining power, move the crucible bottom and the ingot pulling head downward, and start pulling the ingot; at the same time, add the second batch of raw materials into the vacuum suspension melting crucible through the vacuum feeding bin for melting, and the feeding speed is matched with the ingot pulling speed; S5: Vacuum continuous feeding Keep the refining power unchanged and gradually add the next 1 to 4 portions of material; S6: After the ingot pulling is completed, compressed air is filled into the suspension smelting chamber to atmospheric pressure, the furnace door is opened, and the ingot pulling head is controlled to rise to obtain a beryllium copper alloy ingot.

[0006] The present invention adopts vacuum suspension melting to assist vacuum continuous ingot pulling to prepare beryllium copper alloy ingots. The vacuum condition greatly reduces the burnout of beryllium and increases the beryllium yield to greater than 99%. At the same time, the metal yield is greater than 98%. The present invention is carried out under vacuum conditions throughout the entire process, without the need to add carbon materials such as graphite flakes and wood ash, thus avoiding the generation of carbon inclusions in the alloy ingots. The present invention adopts suspension melting to assist vacuum continuous ingot pulling as an integrated preparation process, with fewer steps and no need for multiple transfers of the alloy liquid. In addition, the alloy liquid is in a suspended state during the melting process, which reduces the contact time with the crucible and avoids the introduction of impurities. The present invention adopts suspension melting, and the alloy liquid is strongly stirred under the action of electromagnetic force, which significantly improves production efficiency and reduces energy consumption. DETAILED DESCRIPTION

[0007] The present invention proposes a method for preparing beryllium copper alloy by continuous ingot drawing using suspension smelting, comprising the following steps: S1: Prepare the ingredients and divide them into 3 to 6 portions for later use; S2: drying the raw materials; S3: Cold crucible suspension melting After the first batch of raw materials are loaded into the crucible of the vacuum suspension melting furnace, the melting chamber is closed; the vacuum is pumped to no more than 6.67×10 -3 Pa, after the protective gas is filled to 0.04MPa, gradient temperature rise smelting is carried out; S4: Vacuum continuous ingot pulling Reduce the refining power, move the crucible bottom and the ingot pulling head downward, and start pulling the ingot; at the same time, add the second batch of raw materials into the vacuum suspension melting crucible through the vacuum feeding bin for melting, and match the feeding speed with the ingot pulling speed; S5: Vacuum continuous feeding Keep the refining power unchanged and gradually add the next 1 to 4 portions of material; S6: After the ingot pulling is completed, compressed air is filled into the suspension smelting chamber to atmospheric pressure, the furnace door is opened, and the ingot pulling head is controlled to rise to obtain a beryllium copper alloy ingot.

[0008] In this solution, the steps of multiple feeding, the melting state of the alloy liquid in the crucible, and the step of pulling the ingot from the bottom of the crucible are carried out simultaneously, realizing an integrated continuous process of suspended vacuum melting and vacuum continuous ingot pulling. This solution controls the melting temperature, time and ingot pulling speed to reduce the liquid level fluctuation, stabilize the molten pool, and form an alloy ingot with uniform composition and no segregation.

[0009] The new process of vacuum suspension melting and continuous ingot pulling proposed in the present invention ensures the synchronous operation of feeding, melting and ingot pulling, without breaking the vacuum to transfer the alloy liquid or cooling the ingot separately, thus avoiding the defects of high oxide and carbide content caused by oxidation of the alloy liquid or alloy ingot after breaking the vacuum. Further, S1: the beryllium copper master alloy, electrolytic copper, electrolytic nickel and electrolytic cobalt in the ingredients are weighed according to the chemical composition of the beryllium copper alloy grade, and the beryllium content in the beryllium copper master alloy is 3.6~10 wt%.

[0010] Furthermore, in S2: the drying process, the drying process temperature is 150-250°C, and the drying process time is 4-8 hours.

[0011] Furthermore, the gradient temperature rise smelting of S3 is as follows: the initial smelting heating power is 60~100KW, maintained for 1~3 minutes; then the temperature is continued to rise at 180~240KW, maintained for 4~6 minutes; finally, the beryllium copper alloy liquid is suspended and stirred and refined at 350~380KW, maintained for 10~15 minutes; the refining process temperature is controlled at 1250~1320℃.

[0012] Further, S4: refining power is reduced to 300~350KW.

[0013] Furthermore, the ingot pulling speed is 2-8 mm / min, and the feeding speed is 0.11-0.43 kg / min. The synchronization and continuity of ingot pulling and feeding are ensured, forming an integrated suspension smelting and ingot pulling process. By controlling the ingot pulling speed, feeding speed, and refining power, the fluctuation of the liquid level of the suspension smelting alloy liquid in the crucible is kept small. A stable liquid level during the suspension smelting process ensures uniform composition and a good microstructure. Conversely, when the liquid level is low, the molten pool is shallow, which affects the melting of subsequent feeds and deteriorates the quality of the beryllium copper ingot. When the liquid level is high, the liquid level is close to the upper edge of the crucible, which can easily cause splashing during the smelting process, resulting in material loss and reduced metal yield.

[0014] This solution is an integrated process of vacuum suspension smelting and vacuum continuous ingot pulling. By controlling the smelting temperature, time, ingot pulling speed and material adding speed, the added materials can be quickly and fully stirred, melted and smelted, and the temperature in the molten pool is balanced. At the same time, the speed of pulling the ingot at the bottom is adaptively controlled with the amount of added material and the melting speed, so that the speed of the bottom alloy ingot moving downward and the increase in the liquid level after the added material is melted compensate each other, so that the fluctuation of the liquid level in the molten pool is small, the molten pool is stable, and the alloy ingot formed has uniform composition and no segregation.

[0015] Further, S5: maintain the refining power at 300-350KW, and gradually add 1-4 portions of materials.

[0016] The advantages of the technical solution of the present invention are explained below in combination with three grades of alloys.

[0017] Example 1 S1. Weigh 10.61 kg of beryllium copper master alloy, 9.32 kg of electrolytic copper, 64 g of electrolytic nickel, and 2.5 g of electrolytic cobalt according to the chemical composition requirements of the QBe2 beryllium copper alloy grade, wherein the beryllium content of the beryllium copper master alloy is 3.6 wt %; and divide the mixture into three portions for future use; S2, put the prepared raw materials into a box-type drying furnace and keep them at 150°C for 8 hours to complete the drying of the raw materials; S3, cold crucible suspension melting: after the first batch of raw materials are loaded into the crucible of the vacuum suspension melting furnace, the melting chamber is closed. Vacuum to 6.67×10 -3 Pa, after filling with protective gas to 0.04MPa, gradient heating and melting are carried out. The initial melting heating power is 60KW, maintained for 2 minutes; then the temperature is continued to rise at 180KW, maintained for 6 minutes; finally, the beryllium copper alloy liquid is suspended and stirred and refined at 350KW, maintained for 10 minutes; the refining process temperature is controlled at 1250℃; S4. Vacuum continuous ingot pulling: After reducing the refining power to 300KW, the crucible bottom and the ingot pulling head move downward at a speed of 2 mm / min to start ingot pulling. At the same time, the second batch of raw materials is added to the vacuum suspension melting crucible through the vacuum feeding bin for melting at a feeding rate of 0.11 kg / min. The feeding rate is matched with the ingot pulling speed to ensure that the suspension melting alloy liquid level is maintained at a similar height. S5. Keeping the refining power constant, the third batch of raw materials is added in the same steps. The third batch of raw materials is added at a rate of 0.11 kg / min. At the same time, the bottom of the crucible and the ingot pulling head are kept moving downward at a speed of 2 mm / min.

[0018] S6. After the ingot is pulled, the suspended smelting chamber is filled with compressed air to atmospheric pressure, the furnace door is opened, and the ingot pulling head is controlled to rise to obtain a beryllium copper alloy ingot. The results of the ICP spectrometer test are as follows: Be: 1.91wt%, Ni: 0.315wt%, Co: 0.012wt%, Al: 0.029wt%, Si: 0.044wt%, Pb: 0.001wt%, Fe: 0.059wt%, and the balance is Cu. Calculations show a beryllium metal yield of 99.2% and a metal metal yield of 98.7%, significantly higher than the yields of alloy ingots obtained using conventional non-vacuum induction melting and semi-continuous casting methods.

[0019] Example 2 S1. According to the chemical composition requirements of the C17410 beryllium copper alloy, weigh appropriate amounts of beryllium copper master alloy (1.85 kg), electrolytic copper (18.05 kg), electrolytic nickel (6.3 g), and electrolytic cobalt (100 g), wherein the beryllium content of the beryllium copper master alloy is 3.8 wt %; and divide the mixture into 6 portions for future use; S2. Place the prepared raw materials into a box-type drying furnace and keep them at 250°C for 4 hours to complete the drying of the raw materials; S3, cold crucible suspension melting: after the first batch of raw materials are loaded into the crucible of the vacuum suspension melting furnace, the melting chamber is closed. Vacuum to 6.67×10 -3 After the protective gas is filled to 0.04MPa, the temperature is gradually increased. The initial melting heating power is 100KW and maintained for 1 minute. The temperature is then increased to 240KW and maintained for 4 minutes. Finally, the beryllium copper alloy liquid is suspended and stirred for refining at 380KW for 12 minutes. The refining temperature is controlled at 1320℃.

[0020] S4. Vacuum continuous ingot pulling: After reducing the refining power to 350KW, the crucible bottom and the ingot pulling head move downward at a speed of 8mm / min to start ingot pulling. At the same time, the second batch of raw materials is added to the vacuum suspension melting crucible through the vacuum feeding bin for melting at a feeding rate of 0.42 kg / min. The feeding rate is matched with the ingot pulling speed to ensure that the suspension melting alloy liquid level remains at a similar height. S5. Maintaining the refining power constant, follow the same steps for the next four batches of raw material. Each of the next four batches of raw material is fed at a rate of 0.42 kg / min, while the crucible bottom and ingot pulling head are moved downward at a rate of 8 mm / min.

[0021] S6. After the ingot is pulled, the suspended smelting chamber is filled with compressed air to atmospheric pressure, the furnace door is opened, and the ingot pulling head is controlled to rise to obtain a beryllium copper alloy ingot. The results of the ICP spectrometer test are as follows: Be: 0.351wt%, Ni: 0.031wt%, Co: 0.49wt%, Al: 0.016wt%, Si: 0.022wt%, Pb: 0.001wt%, Fe: 0.024wt%, and the balance is Cu. Calculated beryllium metal yield is 99.37% and metal yield is 99.03%, significantly higher than the yield of alloy ingots produced using existing non-vacuum induction melting and semi-continuous casting methods.

[0022] Example 3 S1. According to the chemical composition requirements of the C17200 beryllium copper alloy, weigh appropriate amounts of beryllium copper master alloy (3.9 kg), electrolytic copper (16.05 kg), electrolytic nickel (2.01 g), and electrolytic cobalt (50.6 g), wherein the beryllium content of the beryllium copper master alloy is 10 wt %, and divide the mixture into four portions for later use; S2. Place the prepared raw materials into a box-type drying furnace and keep them at 200°C for 6 hours to complete the drying of the raw materials; S3, cold crucible suspension melting: after the first batch of raw materials are loaded into the crucible of the vacuum suspension melting furnace, the melting chamber is closed. Vacuum to 6.67×10 -3 After the protective gas is filled to 0.04MPa, the temperature is gradually increased. The initial melting heating power is 80KW and maintained for 1 minute. Then the temperature is further increased at 200KW and maintained for 5 minutes. Finally, the beryllium copper alloy liquid is suspended and stirred for refining at 360KW and maintained for 15 minutes. The refining temperature is controlled at 1260℃.

[0023] S4. Vacuum continuous ingot pulling: After reducing the refining power to 310KW, the crucible bottom and the ingot pulling head move downward at a speed of 3 mm / min to start ingot pulling. At the same time, the second batch of raw materials is added to the vacuum suspension melting crucible through the vacuum feeding bin for melting at a feeding rate of 0.16 kg / min. The feeding rate is matched with the ingot pulling speed to ensure that the suspension melting alloy liquid level remains at a similar height. S5. Maintaining the refining power constant, follow the same steps for the next two batches of raw materials. The feed rate for each of the next two batches is 0.16 kg / min, while maintaining the downward movement of the crucible bottom and the ingot pulling head at a speed of 3 mm / min.

[0024] S6. After the ingot is pulled, the suspended smelting chamber is filled with compressed air to atmospheric pressure, the furnace door is opened, and the ingot pulling head is controlled to rise to obtain a beryllium copper alloy ingot. The results of the ICP spectrometer test are as follows: Be: 1.95wt%, Ni: 0.01wt%, Co: 0.252wt%, Al: 0.018wt%, Si: 0.038wt%, Pb: 0.001wt%, Fe: 0.035wt%, and the balance is Cu. Calculated beryllium yield is 99.16% and metal yield is 98.81%, significantly higher than the yield of alloy ingots produced using existing non-vacuum induction melting and semi-continuous casting methods.

[0025] The above describes the embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of this patent.

Claims

1. A method for preparing beryllium copper alloy by continuous ingot drawing using suspension smelting, characterized in that The following steps are involved: S1: Prepare the ingredients and divide them into 3 to 6 portions for later use; S2: drying the raw materials; S3: cold crucible suspension melting; After the first batch of raw materials are loaded into the crucible of the vacuum suspension melting furnace, the melting chamber is closed; the vacuum is pumped to no more than 6.67×10 -3 Pa, after the protective gas is filled to 0.04MPa, gradient temperature rise smelting is carried out; S4: Vacuum continuous ingot pulling Reduce the refining power, move the crucible bottom and the ingot pulling head downward, and start pulling the ingot; at the same time, add the second batch of raw materials into the vacuum suspension melting crucible through the vacuum feeding bin for melting, and match the feeding speed with the ingot pulling speed; S5: Vacuum continuous feeding Keep the refining power unchanged and gradually add the next 1 to 4 portions of material; S6: After the ingot pulling is completed, compressed air is filled into the suspension smelting chamber to atmospheric pressure, the furnace door is opened, and the ingot pulling head is controlled to rise to obtain a beryllium copper alloy ingot.

2. The method for preparing beryllium copper alloy by continuous ingot drawing using suspension smelting according to claim 1, wherein S1: The beryllium copper master alloy, electrolytic copper, electrolytic nickel and electrolytic cobalt in the ingredients are weighed according to the chemical composition of the beryllium copper alloy grade, and the beryllium content in the beryllium copper master alloy is 3.6-10 wt%.

3. The method for preparing beryllium copper alloy by continuous ingot drawing using suspension smelting according to claim 1, wherein S2: In the drying process, the drying temperature is 150-250° C. and the drying time is 4-8 hours.

4. The method for preparing beryllium copper alloy by continuous ingot drawing using suspension smelting according to claim 1, characterized in that The gradient heating smelting of S3 is as follows: the initial melting heating power is 60~100KW, maintained for 1~3 minutes; then the temperature is continued to rise at 180~240KW, maintained for 4~6 minutes; finally, the beryllium copper alloy liquid is suspended and stirred and refined at 350~380KW, maintained for 10~15 minutes; the refining process temperature is controlled at 1250~1320℃.

5. The method for preparing beryllium copper alloy by continuous ingot drawing using suspension smelting according to claim 1, characterized in that S4: Refining power is reduced to 300~350KW.

6. The method for preparing beryllium copper alloy by continuous ingot drawing using suspension smelting according to claim 5, characterized in that: The ingot pulling speed is 2-8 mm / min, and the feeding speed is 0.11-0.43 kg / min.

7. The method for preparing beryllium copper alloy by continuous ingot drawing using suspension smelting according to claim 1, wherein S5: Maintain the refining power at 300~350KW and gradually add 1~4 portions of material.