Continuous casting system for silver alloys

Abstract

The utility model relates to metal material production and manufacturing technical field, more particularly to a kind of silver alloy's continuous casting system.A kind of silver alloy's continuous casting system, including vacuum induction device, electrode stick, pulse power, crystallization cooling device and support device;The vacuum induction device is to carry out vacuum induction treatment to silver alloy raw material, to form hot melt liquid;One end of the electrode stick is contacted with the hot melt liquid, and the other end of the electrode stick is connected with the positive pole of the pulse power;The crystallization cooling device is to carry out crystallization treatment to the hot melt liquid, to form casting rod;The support device is to support the casting rod, and the casting rod is connected with the negative pole of the pulse power by the support device.The continuous casting system in the utility model, by the cooperation of each device, the growth of columnar crystal can be controlled, the quality and performance of bonding wire and casting are improved, the production cost is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of metal material production and manufacturing technology, and more specifically, to a continuous casting system for silver alloys. Background Technology

[0002] Continuous casting, as a highly efficient metal casting process, is widely used in the production of materials such as steel and non-ferrous metals. Compared with traditional casting methods, continuous casting has advantages such as high production efficiency, high raw material utilization, and environmental friendliness. As an important production step in bond wire preparation, continuous casting directly affects the mechanical properties and reliability of the material. The axially grown columnar crystals in the cast rod can greatly improve the material's drawability.

[0003] During continuous casting, the growth of columnar crystals can vary due to factors such as temperature field, composition, and flow conditions. Columnar crystals typically grow preferentially along a specific direction to form the desired microstructure. However, uncontrolled columnar crystal growth can lead to problems such as crystal defects, inhomogeneous properties, processing difficulties, thermal stress, and deformation, resulting in line breaks in subsequent processing and unstable product quality.

[0004] Therefore, controlling the growth of columnar crystals is crucial to ensuring the performance and quality of the bond line and the entire casting rod. Current continuous casting equipment still suffers from problems such as unsatisfactory columnar crystal growth, uneven performance, high processing difficulty, thermal stress, and deformation.

[0005] In view of the above, this utility model is hereby proposed. Utility Model Content

[0006] One objective of this invention is to provide a continuous casting system for silver alloys, which solves the problems of unsatisfactory growth of columnar crystals, uneven performance, high processing difficulty, thermal stress, and deformation in existing continuous casting devices.

[0007] In order to achieve the above-mentioned objectives of this utility model, the following technical solution is adopted: A continuous casting system for a silver alloy includes a vacuum induction device, an electrode rod, a pulse power supply, a crystallization cooling device, and a support device. The vacuum induction device is used to perform vacuum induction treatment on the silver alloy raw material to form a hot melt. One end of the electrode rod is in contact with the hot melt, and the other end of the electrode rod is connected to the positive terminal of the pulse power supply. The crystallization cooling device is used to crystallize the hot melt to form a casting rod. The support device is used to support the casting rod, and the casting rod is connected to the negative terminal of the pulse power supply through the support device.

[0008] In some embodiments, the top cover of the vacuum sensing device is provided with a first opening, through which the electrode rod contacts the hot melt.

[0009] In some embodiments, the continuous casting system further includes a vacuum pumping device; the top cover of the vacuum sensing device is provided with an air extraction port, and the vacuum pumping device is connected to the air extraction port.

[0010] In some embodiments, the bottom of the vacuum sensing device is provided with a liquid outlet pipe, the crystallization cooling device is provided at the bottom of the vacuum sensing device, and the liquid outlet pipe is housed inside the crystallization cooling device.

[0011] In some embodiments, the crystallization cooling apparatus includes a crystallization apparatus and a cooling apparatus, with the cooling apparatus disposed externally on the crystallization apparatus.

[0012] In some embodiments, the crystallization device is a graphite crystallizer; the cooling device is a water-cooled copper sleeve.

[0013] In some embodiments, the continuous casting system further includes a guide device for pulling the casting rod.

[0014] In some embodiments, the guiding device is a guide wheel.

[0015] In some embodiments, the vacuum sensing device is further provided with a vacuum gauge.

[0016] In some embodiments, an induction coil is provided outside the induction furnace of the vacuum induction device.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows: The continuous casting system of this invention, through the cooperation of various devices, can improve the quality and performance of bond lines and castings, reduce production costs, and increase production efficiency. Specifically, the pulsed power supply energizes the casting rod, and due to the skin effect, the surface of the casting rod is kept in a slightly heated state, reducing the radial temperature gradient and decreasing the growth capacity of radial columnar and equiaxed crystals, thus enabling the dominant growth of axial columnar crystals. This effectively reduces porosity, cracks, and other defects in the casting, improving the mechanical properties and service life of the casting, while also effectively reducing the temperature gradient, resulting in more uniform overall performance of the casting. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1This is a schematic diagram of the continuous casting system of this utility model.

[0020] Figure label: 100-Vacuum induction device, 1-Electrode rod, 2-Vacuum gauge, 3-Induction coil, 4-Cooling device, 5-Guiding device, 6-Supporting device, 7-Casting rod, 8-Pulse power supply, 9-Evacuation port, 10-Crystallization device, 11-Vacuum pumping device. Detailed Implementation

[0021] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] In one aspect, this utility model relates to a continuous casting system for silver alloys, comprising a vacuum induction device, an electrode rod, a pulse power supply, a crystallization cooling device, and a support device; the vacuum induction device is used to perform vacuum induction treatment on the silver alloy raw material to form a hot melt; one end of the electrode rod is in contact with the hot melt, and the other end of the electrode rod is connected to the positive terminal of the pulse power supply; the crystallization cooling device is used to crystallize the hot melt to form a casting rod; the support device is used to support the casting rod, and the casting rod is connected to the negative terminal of the pulse power supply through the support device.

[0024] The continuous casting system of this invention uses a pulsed power supply to energize the casting rod. Due to the skin effect, the surface of the casting rod is kept in a slightly heated state, reducing the radial temperature gradient and decreasing the growth capacity of radial columnar and equiaxed crystals, thus enabling the dominant growth of axial columnar crystals. This effectively reduces porosity, cracks, and other defects in the casting, improving its mechanical properties and service life. Simultaneously, the reduced temperature gradient results in more uniform overall performance of the casting. Through the coordination of various devices, the quality and performance of the bond lines and castings can be improved, production costs reduced, and production efficiency increased.

[0025] In some embodiments, the top cover of the vacuum sensing device has a first opening through which the electrode rod contacts the hot melt. The electrode rod is vertically inserted into the interior of the vacuum sensing device through the first opening, and its lower part is immersed in the hot melt.

[0026] In some embodiments, an induction coil is provided outside the induction furnace of the vacuum induction device.

[0027] In some embodiments, the continuous casting system further includes a vacuum pumping device. In some embodiments, the top cover of the vacuum sensor is provided with an air extraction port, and the vacuum pumping device is connected to the air extraction port. The vacuum pumping device controls the vacuum conditions inside the vacuum sensor. In some embodiments, the vacuum sensor is also equipped with a vacuum gauge to acquire vacuum data.

[0028] In some embodiments, a liquid outlet pipe is provided at the bottom of the vacuum induction device, and the crystallization cooling device is located at the bottom of the vacuum induction device, with the liquid outlet pipe housed inside the crystallization cooling device. In some embodiments, the crystallization cooling device includes a crystallization device and a cooling device, with the cooling device located outside the crystallization device. The crystallization device is a graphite crystallizer; the cooling device is a water-cooled copper sleeve. The crystallization cooling device crystallizes the molten liquid, which is beneficial for subsequent continuous casting.

[0029] In some embodiments, the continuous casting system further includes a guiding device located below the crystallization cooling device for guiding the casting rod. In some embodiments, the guiding device includes a guide wheel. The guide wheel pulls the derrick (connected to the casting at the beginning of casting so that the guide wheel can pull the casting rod) or the casting rod for continuous casting.

[0030] A continuous casting method for a silver alloy includes the following steps: The silver alloy raw material is subjected to vacuum induction treatment to obtain a hot melt. The hot melt is then continuously cast. During the continuous casting process, a pulse power supply is used to energize the cast rod obtained after crystallization and cooling.

[0031] Continuous casting is a crucial production process in bond wire preparation, and the quality of the cast rod significantly impacts the production efficiency and service reliability of the bond wire. Axial growth of columnar crystals in the cast rod can greatly improve the material's drawability. Addressing the uncontrollable growth of columnar crystals during continuous casting, this invention proposes a continuous casting method that promotes the dominant growth of columnar crystals in silver alloys, resulting in cast rods with predominantly axially growing grains. This invention employs a pulsed power supply to energize the cast rod. Due to the skin effect, the cast rod surface is kept in a slightly heated state, reducing the radial temperature gradient and decreasing the growth capacity of radial columnar and equiaxed crystals, thus achieving dominant growth of axial columnar crystals. The introduction of current effectively reduces porosity, cracks, and other defects in the casting, improving its mechanical properties and service life. Simultaneously, it effectively reduces the temperature gradient, resulting in more uniform overall performance of the casting.

[0032] In some embodiments, the voltage of the pulse power supply is 150~220V, including but not limited to 150V, 160V, 170V, 180V, 190V, 200V, 210V, 220V, or any value between two of these. The frequency is 2~20Hz, including but not limited to 2Hz, 3Hz, 5Hz, 8Hz, 10Hz, 12Hz, 15Hz, 18Hz, 20Hz, or any value between two of these. More preferably, the voltage of the pulse power supply is 150~180V, and the frequency is 4~12Hz. This invention employs suitable voltage and frequency of the pulse power supply, which is more conducive to ensuring the advantageous growth of axial columnar crystals, refining grains, and improving the overall performance of silver alloy castings. In some implementations, increasing the pulse current results in the longest columnar crystals at a frequency of 2 Hz. Further increasing the frequency leads to a decrease in columnar crystal length, resulting in grain refinement due to vibrational energy. Although the columnar crystal length decreases, the increased proportion of columnar crystals still enhances the drawing performance and improves the overall performance of the silver alloy casting.

[0033] In some implementations, the current for vacuum induction processing is 15~25A, including but not limited to 15A, 18A, 20A, 22A, 25A, or any value in between.

[0034] In some embodiments, the temperature of the hot melt is 1000~1250℃, including but not limited to 1000℃, 1020℃, 1050℃, 1080℃, 1100℃, 1120℃, 1150℃, 1160℃, 1180℃, 1200℃, 1250℃, or any value between two of these. The temperature is maintained at 1000~1250℃ for 30~60 minutes, with holding times for example, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, or 60 minutes, or any value between two of these. Preferably, the temperature of the hot melt is 1150~1200℃, and the temperature is maintained at 1150~1200℃ for 30~60 minutes. This invention uses a suitable hot melt temperature and holding time to facilitate subsequent continuous casting, promotes the dominant growth of columnar crystals in the silver alloy, and improves the overall performance of the casting.

[0035] In some implementations, before continuous casting, the vacuum conditions of the environment in which the molten metal is located are controlled to be less than 10. -2 Pa, for example 0.005 Pa, 0.008 Pa, 0.009 Pa, etc. The vacuum conditions of this invention can be obtained through vacuuming, and suitable vacuum conditions are beneficial to subsequent continuous casting processes.

[0036] In some embodiments, during the continuous casting process, the hot molten metal from the sprue undergoes crystallization treatment. The crystallization treatment temperature is 600~750℃, including but not limited to 600℃, 620℃, 650℃, 680℃, 700℃, 720℃, or 750℃, or any value between two ranges. The crystallization treatment apparatus is cooled to a temperature of 18~20℃, for example, 18℃, 18.5℃, 19℃, 19.5℃, or 20℃, or any value between two ranges. This invention employs suitable crystallization and cooling temperatures, which is more conducive to ensuring the crystallization effect of the silver alloy and improving its mechanical properties and service life.

[0037] In some embodiments, the casting speed for continuous casting is 4~10 mm / min, such as 4 mm / min, 5 mm / min, 6 mm / min, 8 mm / min, 9 mm / min, 10 mm / min, or any value in between. This invention employs a suitable casting speed, which is more conducive to the continuous casting effect of silver alloys and improves their overall performance.

[0038] In some embodiments, the silver alloy raw material includes silver and doping elements, including gold, copper, and aluminum. The gold content is 1% to 8% by mass, for example, 1%, 2%, 3%, 4%, 5%, 6%, 8%, etc. The copper content is 0% to 8.8% by mass, for example, 1%, 2%, 3%, 5%, 6%, 8.8%, etc. The aluminum content is 0.01% to 0.5% by mass, for example, 0.01%, 0.05%, 0.1%, 0.2%, 0.5%, etc. Gold and silver are infinitely miscible. Adding an appropriate amount of elemental gold can reduce the grain boundary voltage, but too much will increase the cost. An appropriate amount of aluminum can play a good passivation role, protecting the silver from oxidation.

[0039] In some embodiments, the length of the silver alloy columnar crystals is 6 to 14 mm, such as 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, etc.

[0040] In a preferred embodiment, the continuous casting method is implemented using a continuous casting system that promotes the growth of columnar crystals in silver alloys, and includes the following steps: (a) Place the silver alloy raw material into the induction furnace of the vacuum induction device, and insert the electrode rod into the induction furnace. The silver alloy raw material includes pure silver and additive elements (gold, copper, aluminum). Connect the electrode rod to the positive terminal of the pulse power supply. The voltage of the pulse power supply is 150~220V and the frequency is 2~20Hz. Then, use a vacuum pump to evacuate to 0.008Pa, turn on the power supply of the induction furnace, adjust the current to 15~25A, heat the silver alloy raw material to 1000~1250℃, and hold it at that temperature for 30~60min.

[0041] (b) Turn on the casting switch. The guide wheel will pull the casting rod (connected to the casting at the beginning of casting so that the guide wheel can pull the casting rod) or the casting rod. The casting speed is 4~10 mm / min. The casting rod is placed on the support device, which is connected to the negative terminal of the pulse power supply. The temperature of the crystallization device is 600~750℃, and the water temperature in the cooling device is 18~20℃.

[0042] (c) When the continuous casting is connected to the support device, turn on the pulse power switch to perform continuous casting and coil the casting rod around the support device for cooling. After the casting is completed, turn off the pulse power and then turn off the casting switch to end the continuous casting.

[0043] The following explanation, in conjunction with specific embodiments, further clarifies the situation.

[0044] Example 1 A continuous casting system for silver alloys, such as Figure 1As shown, it includes: a vacuum induction device 100, an electrode rod 1, a pulse power supply 8, a vacuum pumping device 11, a crystallization cooling device, a vacuum gauge 2, a guide device 5, and a support device 6; the crystallization cooling device includes a crystallization device 10 and a cooling device 4 located on the outside; the guide device 5 is a guide wheel. The crystallization device 10 is a graphite crystallizer; the cooling device 4 is a water-cooled copper sleeve.

[0045] The vacuum induction device 100 contains silver alloy raw material inside the induction furnace, which is used to perform vacuum induction treatment on the silver alloy raw material to form a hot melt. The top cover of the vacuum induction device 100 is provided with a first opening, and the electrode rod 1 is vertically inserted into the first opening, with one end in contact with the hot melt and the other end of the electrode rod 1 connected to the positive terminal of the pulse power supply 8.

[0046] An induction coil 3 is provided on the outside of the vacuum sensing device 100. An air extraction port 9 and a vacuum gauge 2 are provided on the top of the vacuum sensing device 100, and the air extraction port 9 is connected to the vacuum pumping device 11.

[0047] A liquid outlet pipe is provided at the bottom of the vacuum sensing device 100; the crystallization device 10 is provided at the bottom of the vacuum sensing device 100, and the liquid outlet pipe is housed inside the crystallization device 10.

[0048] The guide device 5 is located at the lower part of the cooling device 4 and is used to pull the casting rod 7.

[0049] The support device 6 is used to support the cast rod 7, which is connected to the negative terminal of the pulse power supply 8 through the support device 6.

[0050] Example 2 A continuous casting method for the dominant growth of columnar crystals in a silver alloy includes the following steps: (1) Pure silver and additive elements (gold, copper, aluminum) are placed in the induction furnace of the vacuum induction device 100, wherein the mass content of gold is 1%, the mass content of copper is 2%, and the mass content of aluminum is 0.3%. The electrode rod 1 is inserted into the induction furnace and connected to the positive terminal of the pulse power supply 8. The voltage of the pulse power supply 8 is 150V and the frequency is 2Hz. Then, the vacuum device 11 is used to evacuate to 0.001Pa, and the power supply of the induction furnace is turned on. The current is adjusted to 20A, and the silver and additive elements are heated to 1160℃ and kept at that temperature for 30min.

[0051] (2) Turn on the casting switch. The guide wheel 5 pulls the casting rod 7. The casting speed is 4 mm / min. The casting rod 7 is placed on the support device 6. The support device 6 supporting the casting rod 7 is connected to the negative terminal of the pulse power supply 8. The temperature of the crystallization device 10 is 700℃, and the water temperature in the cooling device 4 is 19℃.

[0052] (3) When the continuous casting is connected to the support device 6, turn on the pulse power supply 8 switch to perform continuous casting, and coil the casting rod 7 around the support device 6 for cooling. After the casting is completed, turn off the pulse power supply 8, and then turn off the casting switch to end the continuous casting.

[0053] Example 3 A continuous casting method for the dominant growth of columnar crystals in a silver alloy differs from Example 2 in that: The frequency of pulse power supply 8 is 4Hz.

[0054] Example 4 A continuous casting method for the dominant growth of columnar crystals in a silver alloy differs from Example 2 in that: The frequency of pulse power supply 8 is 9Hz.

[0055] Example 5 A continuous casting method for the dominant growth of columnar crystals in a silver alloy differs from Example 2 in that: The silver and added elements are heated to 1250°C.

[0056] Example 6 A continuous casting method for the dominant growth of columnar crystals in a silver alloy differs from Example 2 in that: The silver and added elements are heated to 1000°C.

[0057] Example 7 A continuous casting method for the dominant growth of columnar crystals in a silver alloy differs from Example 2 in that: The casting speed is 10 mm / min.

[0058] Example 8 A continuous casting method for the dominant growth of columnar crystals in a silver alloy differs from Example 2 in that: The temperature of the crystallization apparatus 10 is 600℃.

[0059] Example 9 A continuous casting method for the dominant growth of columnar crystals in a silver alloy differs from Example 2 in that: The temperature of the crystallization apparatus 10 is 750℃.

[0060] Example 10 A continuous casting method for the dominant growth of columnar crystals in a silver alloy differs from Example 2 in that: The voltage of pulse power supply 8 is 200V.

[0061] Comparative Example 1 A continuous casting method for the dominant growth of columnar crystals in silver alloys, except that no pulse power supply is applied, is the same as in Example 2.

[0062] Experimental Example The length of the columnar crystals and the size of the equiaxed crystal grains in each embodiment of the silver alloy were tested, and the proportion of axial columnar crystals was calculated. The results are shown in Table 1.

[0063] Table 1 Test Results

[0064] The continuous casting method for silver alloys in this invention uses a pulsed power supply to energize the casting rod. Due to the skin effect, the surface of the casting rod is kept in a slightly heated state, which reduces the radial temperature gradient of the casting rod and decreases the growth capacity of radial columnar and equiaxed crystals. This allows for the dominant growth of axial equiaxed crystals, resulting in a casting rod with axial grain growth as the main characteristic. The introduction of current can effectively reduce porosity, cracks, and other defects in the casting, improve the mechanical properties and service life of the casting, and effectively reduce the temperature gradient, making the overall performance of the casting more uniform.

[0065] In each embodiment, the length of the columnar crystals in the silver alloy is appropriate, the size of the equiaxed grains is appropriate, and the proportion of axial columnar crystals is appropriate. The microstructure of the cast rod after applying current in Example 1 is excellent. In Comparative Example 1, the microstructure of the cast rod without power supply shows defects, namely cracks and uneven microstructure.

[0066] The aforementioned continuous casting method for silver alloys employs a pulsed power supply to energize the casting rod. Due to the skin effect, the surface of the casting rod is kept in a slightly heated state, reducing the radial temperature gradient and decreasing the growth capacity of radial columnar and equiaxed crystals. This allows for the dominant growth of axial columnar crystals, resulting in a casting rod with predominantly axially growing grains. The introduction of current can effectively reduce porosity, cracks, and other defects in the casting, improving its mechanical properties and service life. It can also effectively reduce the temperature gradient, making the overall performance of the casting more uniform.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A continuous casting system for a silver alloy, characterized in that, Includes a vacuum induction device, electrode rods, pulse power supply, crystallization cooling device, and support device; The vacuum induction device is used to perform vacuum induction treatment on the silver alloy raw material to form a hot melt. One end of the electrode rod is in contact with the hot melt, and the other end of the electrode rod is connected to the positive terminal of the pulse power supply. The crystallization cooling device is used to crystallize the hot melt to form a cast rod; The support device is used to support the cast rod, and the cast rod is connected to the negative terminal of the pulse power supply through the support device; The top cover of the vacuum sensing device is provided with a first opening, through which the electrode rod contacts the hot melt liquid; The continuous casting system also includes a guiding device for pulling the casting rod; The guiding device is a guide wheel.

2. The continuous casting system for silver alloys according to claim 1, characterized in that, The continuous casting system also includes a vacuum pumping device; The top cover of the vacuum sensing device is provided with an air extraction port, and the vacuum pumping device is connected to the air extraction port.

3. The continuous casting system for silver alloys according to claim 1, characterized in that, The vacuum sensing device has a liquid outlet pipe at its bottom, and the crystallization cooling device is located at the bottom of the vacuum sensing device, with the liquid outlet pipe housed inside the crystallization cooling device.

4. The continuous casting system for silver alloys according to claim 3, characterized in that, The crystallization cooling device includes a crystallization device and a cooling device, with the cooling device disposed outside the crystallization device.

5. The continuous casting system for silver alloys according to claim 4, characterized in that, The crystallization device is a graphite crystallizer; The cooling device is a water-cooled copper bushing.

6. The continuous casting system for silver alloys according to claim 1, characterized in that, The vacuum sensing device is also equipped with a vacuum gauge.

7. The continuous casting system for silver alloys according to claim 1, characterized in that, An induction coil is installed outside the induction furnace of the vacuum induction device.

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