A copper rod directional solidification mold and apparatus

Abstract

The utility model relates to metal material processing technical field, concretely relates to a copper pole directional solidification mould and device, the copper pole directional solidification mould, including graphite pipe and ceramic ring, the graphite pipe is equipped with the pouring cavity for pouring copper liquid along the axial direction in the graphite pipe upper and lower end surface through, the graphite pipe includes the upper section, the recess section and the lower section fixed connection in proper order from top to bottom, the wall thickness of upper section is greater than the wall thickness of recess section, the height of lower section is greater than the height of upper section with recess section sum, the ceramic ring is sleeved in the outer periphery of recess section, the inner wall of ceramic ring with the outer wall of recess section fixed connection. The copper pole directional solidification device includes the copper pole directional solidification mould, continuous casting furnace, heat preservation pad and water -cooling copper cover. The copper pole directional solidification mould structure of the application is simple, and the assembly with continuous casting furnace is practical, can prepare the copper pole with directional solidification organization characteristic, is favorable to realize the industrialization popularization.

Description

Technical Field

[0001] This utility model relates to the field of metal material processing technology, specifically to a copper rod directional solidification mold and device. Background Technology

[0002] With the continuous upgrading of conductor material performance indicators in cutting-edge application fields such as ultra-high voltage power transmission, 5G communication networks, and semiconductor precision processing, conventional equiaxed copper materials can no longer meet the combined requirements of ultra-high conductivity and excellent ductility. A new generation of processing technology based on the principle of directional solidification guides the directional solidification of molten copper to form a continuous columnar crystal structure by precisely controlling the unidirectional thermal flow field environment. This product can effectively achieve higher purity, better conductivity, and elongation, providing an ideal material solution for high-end application scenarios.

[0003] Common methods for directional solidification of molten copper include hot-mold casting and warm-mold casting. Hot-mold casting maintains a vertical temperature gradient in the same direction as the copper molten metal by heating the upper part of the mold and preventing lateral heat dissipation. However, its temperature control system is complex and requires extremely high process stability, leading to a surge in energy consumption and low efficiency. Warm-mold casting uses an integral graphite mold to create an environment similar to a unidirectional thermal flow field. Due to the high thermal conductivity of graphite, the radial temperature gradient at the solidification location of the copper rod is large, easily generating a large number of equiaxed crystals with disordered grain orientation. Therefore, methods for directional solidification of molten copper still face many problems in practical applications and cannot meet the needs of industrial-scale promotion. Utility Model Content

[0004] The purpose of this invention is to provide a copper rod directional solidification mold and device, which is applicable to the existing warm mold continuous casting method and solves the problem of unstable columnar crystal growth and excessive impurities on the surface of the copper rod during directional solidification of copper liquid.

[0005] This utility model provides the following technical solution: a copper rod directional solidification mold, comprising: a graphite tube and a ceramic ring;

[0006] The graphite tube has a casting cavity along the axial direction that runs through the upper and lower end faces of the graphite tube for casting molten copper. The graphite tube includes an upper section, a grooved section and a lower section that are fixedly connected from top to bottom. The upper section is used to be inserted into the continuous casting furnace and the wall thickness of the upper section is greater than the wall thickness of the grooved section. The lower section is used to be inserted into a water-cooled environment and the height of the lower section is greater than the sum of the heights of the upper section and the grooved section.

[0007] The ceramic ring is sleeved on the outer periphery of the grooved section, the inner wall of the ceramic ring is fixedly connected to the outer wall of the grooved section, and the outer diameter of the ceramic ring is larger than the outer diameter of the upper section.

[0008] Preferably, the upper section and the lower section have the same wall thickness.

[0009] Preferably, the casting cavity is a hollow cylinder.

[0010] Preferably, the surface roughness Ra of the casting cavity wall is ≤1.6μm, and the surface roughness Ra of the outer wall of the graphite tube is ≤3.2μm.

[0011] Preferably, the diameter of the casting cavity is a, and the wall thickness of the groove section is b, wherein a:b = 1.5 to 3.

[0012] Preferably, a is 6-10 mm and b is 3-5 mm.

[0013] Preferably, the height of the upper section is 30-60mm, the height of the groove section is 20-80mm, and the height of the lower section is 150-300mm.

[0014] This utility model also provides a copper rod directional solidification device, including: a copper rod directional solidification mold as described above, a continuous casting furnace, a heat insulation pad, and a water-cooled copper sleeve;

[0015] The continuous casting furnace includes a crucible, which has a cavity for storing molten copper. The bottom of the crucible has an opening for installing the upper section. The cavity communicates with the casting cavity through the opening. The heat insulation pad is adhesively fitted on the outer periphery of the ceramic ring, and the water-cooled copper sleeve is fitted on the outer periphery of the lower section.

[0016] Preferably, the bottom end of the upper section is flush with the bottom end of the crucible.

[0017] Preferably, the outer diameter of the ceramic ring is larger than the outer diameter of the lower segment.

[0018] Compared with the prior art, the beneficial effects of this utility model are: the overall structure of the copper rod directional solidification mold is relatively simple and the manufacturing cost is low. The outer periphery of the groove section is fitted with a ceramic ring, which reduces the heat conduction effect of the groove section and its corresponding position, so that the heat is conducted along the extension direction of the casting cavity, thereby ensuring the growth advantage of the grains oriented in the same direction as the copper rod traction direction, and producing a copper rod with directional solidification structure characteristics. Therefore, the copper rod directional solidification mold and device of this application are conducive to the industrial promotion. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the graphite tube structure of this application;

[0020] Figure 2 This is a schematic diagram of the copper rod directional solidification mold structure of this application;

[0021] Figure 3 This is a schematic diagram of the copper rod directional solidification device of this application;

[0022] Figure 4 Metallographic image of an 8mm copper rod prepared using the copper rod directional solidification apparatus of this application.

[0023] In the picture:

[0024] 1. Graphite tube; 11. Casting cavity; 12. Upper section; 13. Grooved section; 14. Lower section; 2. Ceramic ring; 3. Crucible; 31. Receptacle; 32. Opening; 4. Insulation pad; 5. Water-cooled copper sleeve. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In the description of the embodiments of this application, 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. They are only for the convenience of describing the embodiments of this application 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 the embodiments of this application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a replaceable 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 the embodiments of this application based on the specific circumstances.

[0028] Combination Figure 1-3As shown, this application provides a copper rod directional solidification mold, including: a graphite tube 1 and a ceramic ring 2; the graphite tube 1 has a casting cavity 11 for casting molten copper that runs through the upper and lower end faces of the graphite tube 1 along the axial direction; the graphite tube 1 includes an upper section 12, a grooved section 13 and a lower section 14 that are fixedly connected from top to bottom; the upper section 12 is used to be inserted into a continuous casting furnace, and the wall thickness of the upper section 12 is greater than the wall thickness of the grooved section 13; the lower section 14 is used to be inserted into a water-cooled environment, and the height of the lower section 14 is greater than the sum of the heights of the upper section 12 and the grooved section 13; the ceramic ring 2 is sleeved on the outer periphery of the grooved section 13, and the inner wall of the ceramic ring 2 is fixedly connected to the outer wall of the grooved section 13; the outer diameter of the ceramic ring 2 is greater than the outer diameter of the upper section 12.

[0029] In this embodiment, the graphite tube 1 is made of high-purity isostatic graphite with a purity greater than 99.99% and a density of 1.82 g / cm³. 3 The ceramic ring 2 is made of materials with good high-temperature stability and thermal conductivity significantly lower than that of graphite. Optional materials include, but are not limited to, alumina, silicon oxide, magnesium oxide, and zirconium oxide. When fixing the ceramic ring 2 to the graphite tube 1, the ceramic powder used to prepare the ceramic ring 2 is directly bonded to an inorganic binder, and then bonded to the outer periphery of the grooved section 13 of the graphite tube 1 before sintering.

[0030] In the continuous casting process of copper rods, the morphology of the crystal structure is closely related to the thermal field distribution at the solidification location. Molten copper flows into the casting cavity 11 from the upper end face of the upper section 12. Graphite has a high thermal conductivity. The positions of the upper section 12 and the casting cavity 11 corresponding to the groove section 13 are both solidification locations of the molten copper. That is, the molten copper solidifies in the upper half of the graphite tube 1. The wall thickness of the groove section 13 is less than that of the upper end, and a ceramic ring 2 with a lower thermal conductivity than graphite is fitted around the outer periphery of the groove section 13, which reduces the heat conduction in the groove section 13. At the same time, the outer diameter of the ceramic ring 2 is larger than that of the upper section 12, which is conducive to the ceramic ring 2 absorbing some of the heat from the upper section 12 to enhance the heat preservation effect on the groove section 13. This can significantly reduce the temperature gradient of the molten copper at the solidification location, especially in the radial direction of the groove section 13, effectively avoiding the dense formation of equiaxed grains on the surface of the copper rod due to a sudden drop in temperature at the solidification location. This strengthens the heat conduction along the casting cavity 11 and ensures that the molten copper solidifies into a copper rod in an axial direction. The casting cavity 11 corresponding to the lower section 14 is the cooling area after the copper liquid solidifies into a copper rod. The lower section 14 is usually placed in a water-cooled environment. The height of the lower section 14 is greater than the sum of the heights of the upper section 12 and the groove section 13, which helps to maintain the necessary temperature gradient for the directional solidification of the copper rod, ensures the correct solidification direction, makes the processing of copper liquid in the graphite tube 1 more consistent, and further guarantees the quality of the product.

[0031] To better shape the graphite tube 1, the upper section 12 and the lower section 14 have the same wall thickness. This consistent wall thickness also avoids stress concentration caused by differences in structural stiffness, effectively extending the service life of the graphite tube 1.

[0032] Furthermore, the casting cavity 11 is a hollow cylinder. Specifically, the casting cavity 11 is located at the axial center of the graphite tube 1. The hollow cylindrical structure has geometric symmetry characteristics, which keeps the heat conduction path of the copper liquid in the casting cavity 11 axially symmetrically distributed and reduces the radial temperature gradient difference.

[0033] Furthermore, the surface roughness Ra of the wall of the casting cavity 11 is ≤1.6μm, and the surface roughness Ra of the outer wall of the graphite tube 1 is ≤3.2μm. The surface roughness of the wall of the casting cavity 11 should be less than the roughness of other walls of the graphite tube 1. In this embodiment, the wall of the casting cavity 11 is polished to a mirror finish to ensure that the surface of the prepared copper rod is bright.

[0034] Furthermore, the diameter of the casting cavity 11 is a, and the wall thickness of the groove section 13 is b, where a:b = 1.5 to 3. To ensure the solidification effect of the molten copper in the casting cavity 11, the wall thickness of the groove section 13 should be adapted to the diameter of the copper rod to be manufactured, that is, adapted to the diameter of the casting cavity 11.

[0035] Furthermore, a is 6–10 mm, and b is 3–5 mm. If the graphite tube 1 has an excessively thin wall thickness, it will lead to excessively high local heat flux density, accelerating the fluctuations at the copper liquid solidification front and affecting the quality of the resulting copper rod. Taking a copper rod with a casting diameter of 8 mm as an example, the wall thickness of the groove section 13 should be 3–5 mm, preferably 5 mm.

[0036] Furthermore, to maintain a stable axial temperature gradient and achieve stepwise cooling, the height of the upper section 12 is 30–60 mm, the height of the grooved section 13 is 20–80 mm, and the height of the lower section 14 is 150–300 mm. Preferably, taking a copper rod with a casting diameter of 8 mm as an example, the height of the upper section 12 is 50 mm, the height of the grooved section 13 is 60 mm, and the height of the lower section 14 is 200 mm, effectively preventing the formation of impurities during the directional solidification of the copper liquid.

[0037] This application also provides a copper rod directional solidification device, comprising: the copper rod directional solidification mold, a continuous casting furnace (not specifically shown in the figure), a heat-insulating pad 4, and a water-cooled copper sleeve 5; the continuous casting furnace includes a crucible 3, the crucible 3 having a accommodating cavity 31 for storing molten copper, the bottom of the crucible 3 having an opening 32 for installing the upper section 12, the accommodating cavity 31 communicating with the casting cavity 11 through the opening 32, the heat-insulating pad 4 being sleeved on the outer periphery of the ceramic ring 2, and the water-cooled copper sleeve 5 being sleeved on the outer periphery of the lower section 14.

[0038] During the downward casting of molten copper, the upper section 12 is inserted into the bottom of the crucible 3 of the continuous casting furnace, fitting tightly with the crucible 3. The molten copper in the crucible 3 flows into the casting cavity 11 of the graphite tube 1. The heat insulation pad 4 is fitted around the outer periphery of the ceramic ring 2 to further enhance the heat insulation effect of the groove section 13. The solidification process of the molten copper during downward casting occurs in the casting cavity 11 corresponding to the groove section 13, ensuring the growth advantage of grains oriented in the same direction as the copper rod traction. The lower part of the graphite tube 1 is inserted into the water-cooled copper sleeve 5 to fully cool the generated copper rod, thereby obtaining a high-quality oriented copper rod. Taking the preparation of a copper rod with a diameter of 8 mm using the copper rod oriented solidification device of this application as an example, the microstructure of the obtained copper rod is as follows: Figure 4 As shown, the prepared copper rod is mainly composed of coarse columnar crystals, exhibiting obvious directional solidification characteristics. Therefore, the directional solidification mold and apparatus for copper rods in this application are simple in structure and easy to implement. The directionally prepared copper rods meet the quality requirements of a continuous columnar crystal structure, which is conducive to the industrial-scale promotion of this application.

[0039] To ensure a tight fit between the upper section 12 and the crucible 3, the bottom end of the upper section 12 is flush with the bottom end of the crucible 3. Specifically, the outer shape and size of the upper section 12 are adapted to the opening 32.

[0040] Furthermore, the outer diameter of the ceramic ring 2 is larger than the outer diameter of the lower section 14. That is, the outer diameter of the ceramic ring 2 is larger than the outer diameters of the upper section 12 and the lower section 14, which facilitates the copper rod directional solidification mold to play a limiting role when assembled with the continuous casting furnace and the water-cooled copper sleeve 5.

[0041] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this application is not limited to the specific embodiments disclosed and described above, and some modifications and changes to this application should also fall within the protection scope of the claims of this application. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this application.

Claims

1. A copper rod directional solidification mold, characterized in that, include: Graphite tubes and ceramic rings; The graphite tube has a casting cavity along the axial direction that runs through the upper and lower end faces of the graphite tube for casting molten copper. The graphite tube includes an upper section, a grooved section and a lower section that are fixedly connected from top to bottom. The upper section is used to be inserted into the continuous casting furnace and the wall thickness of the upper section is greater than the wall thickness of the grooved section. The lower section is used to be inserted into a water-cooled environment and the height of the lower section is greater than the sum of the heights of the upper section and the grooved section. The ceramic ring is sleeved on the outer periphery of the grooved section, the inner wall of the ceramic ring is fixedly connected to the outer wall of the grooved section, and the outer diameter of the ceramic ring is larger than the outer diameter of the upper section.

2. The copper rod directional solidification mold as described in claim 1, characterized in that, The upper and lower sections have the same wall thickness.

3. The copper rod directional solidification mold as described in claim 2, characterized in that, The casting cavity is a hollow cylinder.

4. The copper rod directional solidification mold as described in claim 3, characterized in that, The surface roughness Ra of the casting cavity wall is ≤1.6μm, and the surface roughness Ra of the outer wall of the graphite tube is ≤3.2μm.

5. The copper rod directional solidification mold as described in claim 4, characterized in that, The diameter of the casting cavity is a, and the wall thickness of the groove section is b, where a:b = 1.5~3.

6. The copper rod directional solidification mold as described in claim 5, characterized in that, a is 6-10 mm, b is 3-5 mm.

7. The copper rod directional solidification mold as described in claim 6, characterized in that, The height of the upper section is 30-60mm, the height of the groove section is 20-80mm, and the height of the lower section is 150-300mm.

8. A copper rod directional solidification device, characterized in that, include: The copper rod directional solidification mold, continuous casting furnace, heat insulation pad adhesive, and water-cooled copper sleeve as described in any one of claims 1-7; The continuous casting furnace includes a crucible, which has a cavity for storing molten copper. The bottom of the crucible has an opening for installing the upper section. The cavity communicates with the casting cavity through the opening. The heat insulation pad is adhesively fitted on the outer periphery of the ceramic ring, and the water-cooled copper sleeve is fitted on the outer periphery of the lower section.

9. The copper rod directional solidification device as described in claim 8, characterized in that, The bottom end of the upper section is flush with the bottom end of the crucible.

10. The copper rod directional solidification device as described in claim 9, characterized in that, The outer diameter of the ceramic ring is larger than the outer diameter of the lower section.

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