A pouring tube for a tundish casting system of a vacuum induction melting furnace, and a casting system and operating method thereof

Abstract

The application relates to a pouring pipe for a vacuum induction melting furnace tundish casting system, a pouring pipe casting system and a running method, the pouring pipe is a concentric cylinder structure, the innermost layer is a graphite pipe; the graphite pipe is coated with a self-heating layer and a porous heat preservation layer from inside to outside; the chemical components of the self-heating layer include iron powder, aluminum powder, magnesium powder and a binder. The pouring pipe has a heat compensation function, actively releases heat through internal self-heating materials, does not need an external heat source, completely eliminates external heating systems such as gas and resistance, simplifies the equipment structure, and reduces energy consumption and operation cost.

Description

Technical Field

[0001] This application relates to the field of non-ferrous metal metallurgy technology, and in particular to a casting apparatus for vacuum induction melting and continuous casting of copper and copper alloy melts, especially a gating pipe with autonomous thermal compensation function set between the tundish and the crystallizer. Background Technology

[0002] A vacuum induction melting furnace is a device that uses electromagnetic induction to generate eddy currents within a metal conductor to heat the furnace charge under vacuum conditions. The core advantage of vacuum induction melting over atmospheric melting lies in its complete isolation from gaseous contamination through the vacuum environment. This significantly reduces the oxygen and hydrogen content in the alloy and promotes the volatilization of harmful impurities, resulting in a melt with higher purity. Simultaneously, vacuum induction melting effectively suppresses the loss of easily oxidized elements and enables precise addition and homogenization of highly reactive elements such as chromium and zirconium. Vacuum induction melting has become a key technology for the production of special copper alloys in aerospace, high-end electronics, and other fields.

[0003] The vacuum induction melting and continuous casting furnace is an advanced metallurgical equipment integrating vacuum induction melting and continuous casting functions. Before melting, raw materials are added to the vacuum induction melting furnace, and a vacuum is drawn until the vacuum level meets the process requirements. Electricity is then supplied to raise the temperature, moltenning the raw materials. Through a secondary feeding hopper, additional materials are added and the composition is adjusted without disrupting the vacuum level within the furnace. Simultaneously, a contact temperature measuring device is used for temperature measurement, and multiple samples can be taken. Once the composition and temperature meet the process requirements, inert gas is introduced into the furnace. Under the protection of the inert gas, the molten copper is transferred to the tundish via a chute, and then injected into the crystallizer through a gating pipe (the casting speed can be adjusted via a stopper mechanism). After cooling and solidification into ingots, the ingots are transported out of the pit after cooling to a safe temperature.

[0004] In the vacuum induction melting and continuous casting process, the tundish plays a crucial role as a "central hub," connecting melting and ensuring continuous casting. Its core functions are stabilization, purification, and control: as a buffer container for molten metal, it ensures uniform temperature and stable flow; as the final refining stage, it promotes the flotation and separation of minute impurities. The core advantage of this design lies in its seamless integration of intermittent vacuum melting with continuous casting processes. This not only significantly improves the purity, uniformity, and internal quality of the ingots but also ensures the stability, efficiency, and controllability of the entire continuous casting process. It is an indispensable key link in achieving high performance and high production efficiency for high-end materials.

[0005] In vacuum induction melting and continuous casting processes, the tundish primarily connects the melting furnace and the crystallizer, undertaking the tasks of stabilizing the liquid flow, precisely controlling the speed, uniformizing the temperature, and purifying the melt. The tundish transforms the intermittently smelted copper into a stable, continuous casting flow, ensuring the smooth and controllable operation of the entire continuous casting process. It also effectively isolates the mutual interference between the melting and solidification processes, ultimately significantly improving the purity, microstructure uniformity, and overall production stability of the ingot. The tundish precisely adjusts the casting speed through a stopper rod mechanism and is connected to the crystallizer via a gating pipe.

[0006] In copper alloy casting, the gating pipe is the crucial channel guiding the high-temperature molten copper from the tundish to the crystallizer. Currently, refractory materials such as graphite, quartz, and corundum are commonly used to make gating pipes. Although these materials possess certain refractory properties, they do not generate heat themselves and have high thermal conductivity. During casting, they continuously absorb heat from the molten copper, causing the temperature of the flowing melt to drop. Especially when casting copper alloys containing high-melting-point elements such as nickel and chromium, the melt is prone to localized solidification on the inner wall of the gating pipe, forming slag or blockages, which seriously affects casting continuity and product quality.

[0007] To address these issues, existing technologies often employ external heating devices such as gas nozzles, resistance wires, or induction coils to preheat or heat-trace the casting tube. These methods not only increase equipment complexity and energy consumption but also suffer from problems such as large footprint, heating lag, uneven temperature control, and low thermal efficiency. External heating cannot fundamentally eliminate the low-temperature zone on the tube wall, and the risks of casting tube blockage and inconsistent quality remain.

[0008] Therefore, the fundamental flaw of existing technology lies in the fact that the gating pipe is a passive "cold" channel, unable to actively maintain its own temperature. This has become one of the main bottlenecks restricting the improvement of casting efficiency, leading to product quality defects and unplanned production line interruptions. Therefore, there is an urgent need for a gating pipe with heat compensation function, which can prevent the loss of heat from the molten copper, eliminate the need for external heating devices, and has a simple structure. Summary of the Invention

[0009] To address the aforementioned technical problems, this application provides a gating pipe for a vacuum induction melting furnace tundish casting system, along with its casting system and operating method. The gating pipe of this application requires no external heating device and can actively and rapidly raise and maintain its operating temperature through internal self-heating materials, effectively preventing heat loss and localized solidification of the molten copper during transport, thereby ensuring the continuous and stable casting process and the quality of the ingot.

[0010] To achieve this objective, the following technical solution is adopted in this application:

[0011] In a first aspect, this application provides a gating pipe for a casting system of a vacuum induction melting furnace tundish, wherein the gating pipe has a concentric cylindrical structure and the innermost layer is a graphite tube; the graphite tube is covered from the inside out with a self-heating layer and a porous insulation layer;

[0012] The chemical composition of the self-heating layer includes iron powder, aluminum powder, magnesium powder, and binder.

[0013] The gating tube of this application has a thermal compensation function. It actively releases heat through a self-heating layer, eliminating the need for an external heat source and completely eliminating external heating systems such as gas or electric resistance. This simplifies the equipment structure and reduces energy consumption and operating costs. It has high thermal efficiency and good insulation. The heating layer is in close contact with the graphite tube, and heat is transferred directly inward. The outer porous insulation layer ensures oxygen supply for the reaction and significantly reduces heat loss, resulting in a significant improvement in overall thermal efficiency. It is convenient to use and safe and reliable. The gating tube adopts a ready-to-use design without the need for a complicated preheating procedure. The reaction process does not require electricity or flames, avoiding related safety hazards.

[0014] It should be noted that the gating pipe of this application is vacuum-sealed when not in use to isolate it from air and prevent the self-heating layer from reacting prematurely.

[0015] The working principle of the self-heating layer in this application is as follows: When the casting tube is removed from the vacuum packaging and comes into contact with air, the magnesium powder first oxidizes, with the reaction equation 2Mg + O2 → 2MgO, which releases heat. The iron powder oxidizes upon contact with air, generating Fe3O4 powder, with the reaction equation 3Fe + 2O2 → Fe3O4. The heat generated by the magnesium powder oxidation reaction promotes the aluminothermic reaction between the aluminum powder and Fe3O4 powder: Fe2O3 + 2Al → 2Fe + Al2O3, generating a large amount of heat and rapidly raising the surface temperature of the graphite tube to over 1100℃, thus providing continuous thermal compensation for the flowing copper liquid.

[0016] In this application, the gating pipe is a concentric cylindrical structure, with the innermost layer being a graphite tube. The graphite tube is in direct contact with the molten copper during the copper alloy casting process, guiding the high-temperature molten copper from the holding furnace to the crystallizer. It has good high-temperature stability, corrosion resistance, and thermal conductivity.

[0017] In some embodiments, the thickness of the graphite tube is 8-15mm, such as 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc., but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0018] It should be noted that this application does not impose specific requirements or special limitations on the diameter and length of the graphite tube. Those skilled in the art can make adaptive adjustments to the diameter and length of the graphite tube according to the actual situation.

[0019] In some embodiments, the thickness of the self-heating layer is 5-15mm, such as 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 12mm, 14mm, 15mm, etc., but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0020] In some embodiments, the thickness of the porous insulation layer is 10-20mm, such as 10mm, 12mm, 14mm, 16mm, 18mm, 19mm, etc., but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0021] In some embodiments, the porosity of the porous insulation layer is 40-60%, such as 40%, 45%, 50%, 55%, 60%, etc., but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0022] In some embodiments, the pore size of the porous insulation layer is 0.1-1.0 mm, such as 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, etc., but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0023] In some embodiments, the self-heating layer comprises, by weight percentage, 30-40% iron powder, 40-50% aluminum powder, 20-30% magnesium powder, with the remainder being a binder.

[0024] The content of the iron powder is 30-40%, such as 30%, 31%, 32%, 34%, 36%, 38%, 40%, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0025] The aluminum powder content is 40-50%, such as 40%, 42%, 44%, 46%, 48%, 50%, etc., but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0026] The content of magnesium powder is 20-30%, such as 20%, 22%, 24%, 26%, 28%, 30%, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0027] The self-heating layer of this application reacts rapidly and has a controllable temperature. The magnesium powder oxidation and aluminothermic reaction start quickly, which can make the casting tube reach and maintain a suitable working temperature in a short time. In addition, the heat release power can be controlled by adjusting the self-heating layer ratio and thickness.

[0028] It should be noted that the self-heating layer of this application is wrapped around the outside of the graphite tube and is made of iron powder, aluminum powder, magnesium powder and adhesive pressed in a vacuum environment. After being pressed and formed, it is cured at low temperature to form a composite layer with a certain strength and porosity.

[0029] In some embodiments, the adhesive comprises an inorganic adhesive; the inorganic adhesive comprises silica sol and / or phosphate.

[0030] In some embodiments, the porous insulation layer comprises asbestos fiber or ceramic fiber paper.

[0031] The porous insulation layer of this application has a porous structure, which effectively suppresses convective heat loss while ensuring air circulation.

[0032] It should be noted that the porous insulation layer of this application is wrapped around the self-heating layer by wet winding or molding process.

[0033] In a second aspect, this application provides a vacuum induction melting furnace tundish casting system, the vacuum induction melting furnace tundish casting system including the gating pipe as described in the first aspect;

[0034] The vacuum induction melting furnace tundish casting system also includes a tundish, a stopper rod mechanism, and a crystallizer;

[0035] The tundish has a gate at its bottom; the stopper mechanism includes a stopper, a drive device, and a transmission system.

[0036] The stopper rod is disposed inside the tundish and blocks the gate; the drive device and transmission system are used to control the up and down movement of the stopper rod;

[0037] The gating pipe connects the tundish and the crystallizer through the gating gate.

[0038] In some embodiments, the outer wall of the tundish is made of steel, and the inner wall is made of refractory material.

[0039] In some embodiments, an induction coil is provided inside the tundish for electromagnetic induction heating of the molten casting liquid inside the tundish.

[0040] In some embodiments, the crystallizer is provided with an inlet and an outlet for cooling the molten casting liquid.

[0041] Thirdly, this application provides a method for operating a vacuum induction melting furnace tundish casting system as described in the second aspect, the method comprising:

[0042] After the temperature of the gating pipe rises, the stopper rod is controlled to move upward through the drive device and transmission system. The molten casting in the tundish flows into the high-temperature gating pipe and remains in a molten state as it flows toward the crystallizer.

[0043] In some embodiments, the temperature of the gating pipe is raised to above 1100°C.

[0044] It should be noted that the gating pipe is first installed on the tundish casting system of the vacuum induction melting furnace. Before casting begins, the vacuum packaging is torn open. Casting begins after the temperature of the gating pipe reaches 1100℃. The molten copper flows out of the tundish and enters the crystallizer through the gating pipe. The crystallizer is circulated with cooling water, which can cause the molten copper to form a solidified billet shell. The solidified billet is pulled downward by the ingot guide rod to achieve continuous casting.

[0045] The specific operating method includes: before the casting operation, the vacuum-packed gating tube is installed in place. Approximately 10-15 minutes before the actual casting, the vacuum packaging is removed, allowing air to permeate through the porous insulation layer to the self-heating layer. The self-heating layer rapidly undergoes an exothermic oxidation reaction, raising the temperature of the graphite tube's inner wall to over 1100℃ within about 5-8 minutes. At this point, the stopper rod is raised, and the molten copper in the tundish flows into the high-temperature gating tube, where it remains molten under this thermal compensation effect and flows towards the crystallizer, completing continuous casting. Throughout the casting process, the self-heating reaction continues, providing stable thermal compensation for the gating tube.

[0046] Throughout the casting process, the porous insulation layer allows air to slowly permeate into the self-heating layer to maintain the reaction, while also utilizing the low thermal conductivity of asbestos material to reduce heat loss to the environment and make the heat transfer to the graphite tube more concentrated.

[0047] Compared with the prior art, this application has at least the following beneficial effects:

[0048] (1) The gating pipe of this application has a heat compensation function. It actively releases heat through the internal self-heating layer, eliminating the need for an external heat source, thus completely eliminating the need for external heating systems such as gas and resistance, simplifying the equipment structure, and reducing energy consumption and operating costs.

[0049] (2) The self-heating layer of this application reacts quickly and the temperature is controllable. The magnesium powder oxidation and aluminothermic reaction start up quickly, which can make the casting tube reach and maintain a suitable working temperature (≥1100℃) in a short time. The heat release power can be controlled by adjusting the heat release layer ratio and thickness.

[0050] (3) The casting tube of this application has high thermal efficiency and good heat preservation. The heating layer is closely attached to the graphite tube, and the heat is directly transferred to the inside. The porous insulation layer of the outer layer not only ensures oxygen supply for the reaction, but also significantly reduces heat loss, and the overall thermal efficiency is greatly improved.

[0051] (4) The gating pipe of this application is convenient to use, safe and reliable. The gating pipe adopts a design that can be disassembled and used immediately, without the need for a complicated preheating procedure; the reaction process does not require power or flame, thus avoiding related safety hazards. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the overall structure of a gating pipe for a vacuum induction melting furnace tundish casting system provided in this application.

[0053] Figure 2 This is an axial sectional view of a gating pipe for a tundish casting system in a vacuum induction melting furnace, as provided in this application.

[0054] Among them, 5 is a graphite tube; 6 is a self-heating layer; and 7 is a porous insulation layer.

[0055] Figure 3 This is a schematic diagram of the structure of a vacuum induction melting furnace tundish casting system provided in this application.

[0056] Among them, 1. Stopper rod; 2. Tundish; 3. Gating pipe; 4. Crystallizer; 4.1. Inlet; 4.2. Outlet. Detailed Implementation

[0057] The technical solution of this application will be further described below with reference to the accompanying drawings and specific embodiments. However, the examples below are merely simplified examples of this application and do not represent or limit the scope of protection of this application. The scope of protection of this application shall be determined by the claims.

[0058] Example 1

[0059] This embodiment provides a gating pipe for a vacuum induction melting furnace tundish casting system. The gating pipe has a concentric cylindrical structure, with the innermost layer being a graphite tube 5. The graphite tube 5 is covered from the inside out with a self-heating layer 6 and a porous insulation layer 7.

[0060] The graphite tube 5 has an inner diameter of 80 mm, a thickness of 10 mm, and a length of 500 mm.

[0061] The self-heating layer 6 has a thickness of 15 mm and, by mass percentage, comprises 35% iron powder, 42% aluminum powder, 23% magnesium powder, and 5% silica sol binder; after pressing and curing, its bulk density is approximately 2.8 g / cm³. 3 ;

[0062] The porous insulation layer 7 is made of asbestos fiber, with a thickness of 20mm, a porosity of 50%, and a pore size of 0.1mm.

[0063] After the casting tube is unsealed and exposed to air, the temperature at the center of the inner wall of the graphite tube reaches 1150℃ after about 6 minutes, which can be used to cast high-melting-point copper alloys such as copper-chromium-zirconium.

[0064] Example 2

[0065] This embodiment provides a gating pipe for a vacuum induction melting furnace tundish casting system. The gating pipe has a concentric cylindrical structure, with the innermost layer being a graphite tube 5. The graphite tube 5 is covered from the inside out with a self-heating layer 6 and a porous insulation layer 7.

[0066] The graphite tube 5 has an inner diameter of 30 mm, a thickness of 8 mm, and a length of 300 mm.

[0067] The self-heating layer 6 has a thickness of 10 mm and, by mass percentage, comprises 38% iron powder, 40% aluminum powder, 22% magnesium powder, and 5% aluminum phosphate binder.

[0068] The porous insulation layer 7 is made of ceramic fiber, with a thickness of 15mm, a porosity of 40%, and a pore size of 0.5mm.

[0069] The gating pipe is suitable for casting special alloys that are sensitive to temperature fluctuations. It takes about 8 minutes to heat up to 1100°C, but the heat compensation duration is longer and the temperature stability is better.

[0070] Example 3

[0071] This embodiment provides a gating pipe for a vacuum induction melting furnace tundish casting system. The gating pipe has a concentric cylindrical structure, with the innermost layer being a graphite tube 5. The graphite tube 5 is covered from the inside out with a self-heating layer 6 and a porous insulation layer 7.

[0072] The graphite tube 5 has an inner diameter of 50 mm, a thickness of 15 mm, and a length of 300 mm.

[0073] The self-heating layer 6 has a thickness of 5 mm and, by mass percentage, comprises 30% iron powder, 45% aluminum powder, 20% magnesium powder, and 5% aluminum phosphate binder.

[0074] The porous insulation layer 7 is made of ceramic fiber, with a thickness of 10 mm, a porosity of 60%, and a pore size of 1.0 mm.

[0075] Example 4

[0076] This embodiment provides a gating pipe for a vacuum induction melting furnace tundish casting system. The difference from Embodiment 1 is that the iron powder content in the self-heating layer 6 is 25%, while the rest is the same as in Embodiment 1.

[0077] Example 5

[0078] This embodiment provides a gating pipe for a vacuum induction melting furnace tundish casting system. The difference from Embodiment 1 is that the iron powder content in the self-heating layer 6 is 45%, while the rest is the same as in Embodiment 1.

[0079] Example 6

[0080] This embodiment provides a gating pipe for a vacuum induction melting furnace tundish casting system. The difference from Embodiment 1 is that the aluminum powder content in the self-heating layer 6 is 35%, while the rest is the same as in Embodiment 1.

[0081] Example 7

[0082] This embodiment provides a gating pipe for a vacuum induction melting furnace tundish casting system. The difference from Embodiment 1 is that the aluminum powder content in the self-heating layer 6 is 55%, while the rest is the same as in Embodiment 1.

[0083] Example 8

[0084] This embodiment provides a gating pipe for a vacuum induction melting furnace tundish casting system. The difference from Embodiment 1 is that the thickness of the self-heating layer 6 is 2mm, while all other aspects are the same as in Embodiment 1.

[0085] Example 9

[0086] This embodiment provides a gating pipe for a vacuum induction melting furnace tundish casting system. The difference from Embodiment 1 is that the thickness of the self-heating layer 6 is 20mm, while all other aspects are the same as in Embodiment 1.

[0087] Comparative Example 1

[0088] This comparative example provides a gating pipe for a vacuum induction melting furnace tundish casting system. The difference from Example 1 is that the self-heating layer 6 is not provided, and the gating pipe is heated by an external heating device. All other aspects are the same as in Example 1.

[0089] Comparative Example 2

[0090] This comparative example provides a gating pipe for a tundish casting system in a vacuum induction melting furnace. The difference from Example 1 is that the porous insulation layer 7 is not provided, but all other aspects are the same as in Example 1.

[0091] Comparative Example 3

[0092] This comparative example provides a gating pipe for a tundish casting system in a vacuum induction melting furnace. The difference from Example 1 is that the iron powder in the self-heating layer 6 is replaced with magnesium powder, while the rest is the same as in Example 1.

[0093] Comparative Example 4

[0094] This comparative example provides a gating pipe for a vacuum induction melting furnace tundish casting system. The difference from Example 1 is that the aluminum powder in the self-heating layer 6 is replaced with magnesium powder, while the rest is the same as in Example 1.

[0095] Application Example 1

[0096] This application example provides a vacuum induction melting furnace tundish casting system, which includes the gating pipe 3 described in Example 1;

[0097] The vacuum induction melting furnace tundish casting system also includes a tundish 2, a stopper mechanism, and a crystallizer 4;

[0098] The bottom of the tundish 2 is provided with a gate; the stopper mechanism includes a stopper 1, a drive device and a transmission system;

[0099] The stopper rod 1 is disposed inside the tundish 2 and blocks the gate; the drive device and transmission system are used to control the up and down movement of the stopper rod 1;

[0100] The gating pipe 3 is connected to the tundish 2 and the crystallizer 4 through the gating port;

[0101] The outer wall of the tundish 2 is made of steel, and the inner wall is made of refractory material. An induction coil is installed inside the tundish 2 for electromagnetic induction heating of the molten casting liquid inside the tundish 2.

[0102] The crystallizer 4 is provided with an inlet 4.1 and an outlet 4.2 for cooling the molten casting liquid;

[0103] This application example also provides a method for operating the aforementioned vacuum induction melting furnace tundish casting system, the method comprising:

[0104] Before the casting operation, the vacuum-packed gating pipe 3 is installed in place. About 10-15 minutes before the formal casting, the vacuum packaging is removed, allowing air to permeate through the porous insulation layer 7 to the self-heating layer 6. The self-heating layer 6 rapidly undergoes an exothermic oxidation reaction, raising the temperature of the inner wall of the graphite tube 5 to over 1100℃ within about 5-8 minutes. At this time, the stopper rod 1 is moved upward by the drive device and transmission system, and the molten copper in the tundish 2 flows into the high-temperature gating pipe 3. Under this thermal compensation, it remains in a molten state and flows towards the crystallizer 4, completing continuous casting.

[0105] Application Example 2

[0106] This application example provides a vacuum induction melting furnace tundish casting system, which includes the gating pipe 3 described in Example 2;

[0107] The vacuum induction melting furnace tundish casting system also includes a tundish 2, a stopper mechanism, and a crystallizer 4;

[0108] The bottom of the tundish 2 is provided with a gate; the stopper mechanism includes a stopper 1, a drive device and a transmission system;

[0109] The stopper rod 1 is disposed inside the tundish 2 and blocks the gate; the drive device and transmission system are used to control the up and down movement of the stopper rod 1;

[0110] The gating pipe 3 is connected to the tundish 2 and the crystallizer 4 through the gating port;

[0111] The outer wall of the tundish 2 is made of steel, and the inner wall is made of refractory material. An induction coil is installed inside the tundish 2 for electromagnetic induction heating of the molten casting liquid inside the tundish 2.

[0112] The crystallizer 4 is provided with an inlet 4.1 and an outlet 4.2 for cooling the molten casting liquid;

[0113] This application example also provides a method for operating the aforementioned vacuum induction melting furnace tundish casting system, the method comprising:

[0114] After the temperature of the gating pipe rises above 1100℃, the stopper rod is controlled to move upward through the drive device and transmission system. The molten casting in the tundish flows into the high-temperature gating pipe and remains in a molten state as it flows toward the crystallizer.

[0115] Application Example 3

[0116] This application example provides a vacuum induction melting furnace tundish casting system, which includes the gating pipe 3 described in Example 3;

[0117] The vacuum induction melting furnace tundish casting system also includes a tundish 2, a stopper mechanism, and a crystallizer 4;

[0118] The bottom of the tundish 2 is provided with a gate; the stopper mechanism includes a stopper 1, a drive device and a transmission system;

[0119] The stopper rod 1 is disposed inside the tundish 2 and blocks the gate; the drive device and transmission system are used to control the up and down movement of the stopper rod 1;

[0120] The gating pipe 3 is connected to the tundish 2 and the crystallizer 4 through the gating port;

[0121] The outer wall of the tundish 2 is made of steel, and the inner wall is made of refractory material. An induction coil is installed inside the tundish 2 for electromagnetic induction heating of the molten casting liquid inside the tundish 2.

[0122] The crystallizer 4 is provided with an inlet 4.1 and an outlet 4.2 for cooling the molten casting liquid;

[0123] This application example also provides a method for operating the aforementioned vacuum induction melting furnace tundish casting system, the method comprising:

[0124] After the temperature of the gating pipe rises above 1100℃, the stopper rod is controlled to move upward through the drive device and transmission system. The molten casting in the tundish flows into the high-temperature gating pipe and remains in a molten state as it flows toward the crystallizer.

[0125] Application Example 4

[0126] This application example provides a vacuum induction melting furnace tundish casting system. The difference between this system and Application Example 1 is that the vacuum induction melting furnace tundish casting system includes the gating pipe 3 described in Example 4. All other aspects are the same as in Application Example 1.

[0127] Application Example 5

[0128] This application example provides a vacuum induction melting furnace tundish casting system. The difference between this system and application example 1 is that the vacuum induction melting furnace tundish casting system includes the gating pipe 3 described in example 5, while all other aspects are the same as in application example 1.

[0129] Application Example 6

[0130] This application example provides a vacuum induction melting furnace tundish casting system. The difference between this system and Application Example 1 is that the vacuum induction melting furnace tundish casting system includes the gating pipe 3 described in Example 6, while all other aspects are the same as in Application Example 1.

[0131] Application Example 7

[0132] This application example provides a vacuum induction melting furnace tundish casting system. The difference between this system and Application Example 1 is that the vacuum induction melting furnace tundish casting system includes the gating pipe 3 described in Example 7, while all other aspects are the same as in Application Example 1.

[0133] Application Example 8

[0134] This application example provides a vacuum induction melting furnace tundish casting system. The difference between this system and Application Example 1 is that the vacuum induction melting furnace tundish casting system includes the gating pipe 3 described in Example 8, while all other aspects are the same as in Application Example 1.

[0135] Application Example 9

[0136] This application example provides a vacuum induction melting furnace tundish casting system. The difference between this system and application example 1 is that the vacuum induction melting furnace tundish casting system includes the gating pipe 3 described in example 9, while all other aspects are the same as in application example 1.

[0137] Comparative Application Example 1

[0138] This application example provides a vacuum induction melting furnace tundish casting system. The difference between this system and Application Example 1 is that the vacuum induction melting furnace tundish casting system includes the gating pipe 3 described in Comparative Example 1. Everything else is the same as in Application Example 1.

[0139] Comparative Application Example 2

[0140] This application example provides a vacuum induction melting furnace tundish casting system. The difference between this system and Application Example 1 is that the vacuum induction melting furnace tundish casting system includes the gating pipe 3 described in Comparative Example 2. All other aspects are the same as in Application Example 1.

[0141] Comparative Application Example 3

[0142] This application example provides a vacuum induction melting furnace tundish casting system. The difference between this system and Application Example 1 is that the vacuum induction melting furnace tundish casting system includes the gating pipe 3 described in Comparative Example 3. All other aspects are the same as in Application Example 1.

[0143] Comparative Application Example 4

[0144] This application example provides a vacuum induction melting furnace tundish casting system. The difference between this system and Application Example 1 is that the vacuum induction melting furnace tundish casting system includes the gating pipe 3 described in Comparative Example 4. All other aspects are the same as in Application Example 1.

[0145] Results Analysis

[0146] (1) As can be seen from Application Examples 1 to 3, this application sets up a gating pipe with heat compensation function, and actively and rapidly raises and maintains the working temperature through the internal self-heating layer, effectively preventing the loss of heat and local solidification of copper liquid during the transmission process, thereby ensuring the continuous stability of the casting process and the quality of the ingot.

[0147] (2) As can be seen from Application Example 1 and Application Examples 4-9, this application can control the heat release power by adjusting the composition ratio and thickness of the self-heating layer. If it exceeds the range specified in this application, the working temperature of the gating pipe will be too low or unstable, thereby affecting the stability of the casting process and the quality of the ingot.

[0148] (3) It can be seen from Application Example 1 and Comparative Application Examples 1-4 that the gating pipe used in Comparative Application Example 1 does not have a self-heating layer 6, but uses an external heating device to heat the gating pipe. This not only increases the complexity of the equipment and energy consumption, but also has problems such as large footprint, heating lag, uneven temperature control, and low thermal efficiency. It is difficult to fundamentally eliminate the low temperature zone of the pipe wall, and the risk of gating pipe blockage and quality instability still exists. The gating pipe in Comparative Application Example 2 does not have a porous insulation layer 7, which makes it impossible to maintain a stable temperature of the gating pipe during the casting process, and there is a risk of gating pipe blockage and quality instability. In Comparative Application Examples 3 and 4, the iron powder, aluminum powder, etc. in the self-heating layer 6 are replaced with magnesium powder, which makes it impossible for the self-heating layer of the gating pipe to release heat normally, thereby affecting the stability of the casting process and the quality of the ingot.

[0149] In summary, this application provides a gating pipe for a vacuum induction melting furnace tundish casting system, as well as the casting system and operating method thereof. The gating pipe of this application has a thermal compensation function, actively releasing heat through a self-heating layer, eliminating the need for an external heat source, completely eliminating external heating systems such as gas or resistance heating, simplifying the equipment structure, and reducing energy consumption and operating costs; it has high thermal efficiency and good insulation, with the heating layer closely attached to the graphite tube, allowing heat to be transferred directly inward; the outer porous insulation layer ensures oxygen supply for the reaction while significantly reducing heat loss, resulting in a substantial improvement in overall thermal efficiency; it is convenient to use, safe and reliable, with the gating pipe designed for immediate use without complex preheating procedures; the reaction process requires no power or flame, avoiding related safety hazards.

[0150] The applicant declares that the above description is only a specific implementation of this application, but the protection scope of this application is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application fall within the protection and disclosure scope of this application.

Claims

1. A gating pipe for a tundish casting system in a vacuum induction melting furnace, characterized in that, The pouring pipe has a concentric cylindrical structure, with the innermost layer being a graphite tube; the graphite tube is covered from the inside out with a self-heating layer and a porous insulation layer; The chemical composition of the self-heating layer includes iron powder, aluminum powder, magnesium powder, and binder.

2. The gating pipe according to claim 1, characterized in that, The thickness of the graphite tube is 8-15 mm; And / or, the thickness of the self-heating layer is 5-15mm; And / or, the thickness of the porous insulation layer is 10-20 mm.

3. The gating pipe according to claim 1, characterized in that, The porosity of the porous insulation layer is 40-60%; And / or, the pore size of the porous insulation layer is 0.1-1.0 mm.

4. The gating pipe according to claim 1, characterized in that, The self-heating layer comprises 30-40% iron powder, 40-50% aluminum powder, and 20-30% magnesium powder by weight, with the remainder being a binder.

5. The gating pipe according to claim 1, characterized in that, The adhesive includes an inorganic adhesive; the inorganic adhesive includes silica sol and / or phosphate; And / or, the porous insulation layer comprises asbestos fiber or ceramic fiber paper.

6. A vacuum induction melting furnace tundish casting system, characterized in that, The vacuum induction melting furnace tundish casting system includes the gating pipe as described in any one of claims 1-5; The vacuum induction melting furnace tundish casting system also includes a tundish, a stopper rod mechanism, and a crystallizer; The tundish has a gate at its bottom; the stopper mechanism includes a stopper, a drive device, and a transmission system. The stopper rod is disposed inside the tundish and blocks the gate; the drive device and transmission system are used to control the up and down movement of the stopper rod; The gating pipe connects the tundish and the crystallizer through the gating gate.

7. The vacuum induction melting furnace tundish casting system according to claim 6, characterized in that, The outer wall of the tundish is made of steel, and the inner wall is made of refractory material; And / or, an induction coil is provided inside the intermediate ladle for electromagnetic induction heating of the molten casting liquid inside the intermediate ladle.

8. The vacuum induction melting furnace tundish casting system according to claim 6, characterized in that, The crystallizer is equipped with an inlet and an outlet for cooling the molten casting liquid.

9. A method for operating a vacuum induction melting furnace tundish casting system as described in any one of claims 6-8, characterized in that, The operating method includes: After the temperature of the gating pipe rises, the stopper rod is controlled to move upward through the drive device and transmission system. The molten casting in the tundish flows into the high-temperature gating pipe and remains in a molten state as it flows toward the crystallizer.

10. The operating method according to claim 9, characterized in that, The temperature of the gating pipe rises to over 1100°C.

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