Thin-wall high-temperature damping alloy pipe fitting as well as preparation method and pouring system thereof

Abstract

The invention discloses a thin-wall high-temperature damping alloy pipe fitting as well as a preparation method and a pouring system thereof. The alloy comprises the following chemical elements in percentage by mass: 13-17wt.% of Cu; wt.% of Ni: 8 to 15; 2 to 6 wt.% of Fe; %, 3 to 9 wt.% of Zn; %, 0.5 to 3 wt.% of Al; the balance is Mn and other inevitable impurities; the preparation method comprises the following steps: weighing raw materials according to the proportion of component elements of the high-temperature damping alloy, melting the raw materials under a vacuum condition, preserving heat at 1400-1600 DEG C, fully melting the raw materials to form alloy liquid, and casting the alloy liquid to obtain the thin-wall high-temperature damping alloy pipe fitting. The preparation method comprises the steps of mold preparation, alloy smelting, pouring, cooling, demolding, post-treatment and quality detection. And the pouring system comprises a pouring cup, a straight pouring gate, a transverse pouring gate, an inner pouring gate and an exhaust passage. Alloy components are optimized, the mold filling capacity of alloy liquid is improved, the surface quality of the thin-wall pipe fitting is good, no obvious defect exists, and the alloy liquid is widely applied to the fields of aerospace, automobiles, ships, high-precision instrument manufacturing and the like.

Description

Technical Field

[0001] This invention relates to the field of alloy pipe manufacturing technology, and more particularly to a high-temperature damping alloy pipe, its manufacturing method and gating system, especially to a thin-walled damping alloy pipe, its manufacturing method and gating system. Background Technology

[0002] Damping alloys are a class of special functional materials whose main characteristic is their ability to reduce vibration by consuming mechanical energy. These materials effectively absorb and dissipate vibration energy caused by external forces, thereby reducing noise, minimizing mechanical fatigue, and extending equipment lifespan. Damping alloys are widely used in aerospace, automotive, shipbuilding, and high-precision instrument manufacturing. Mn-based damping alloys are renowned for their excellent damping performance, maintaining good damping effects even at high temperatures. The damping mechanism of high-temperature damping alloys primarily stems from phase transitions and microstructural changes within their crystal lattice. When external mechanical forces are applied, the internal structure adaptively adjusts, dissipating energy and reducing vibration. Traditional metal pipe fittings exhibit significantly reduced damping performance at high temperatures (≥400℃), making it difficult to effectively suppress vibration and noise.

[0003] Patent application CN202111078662.7 discloses a high-entropy high-temperature manganese-based damping alloy material and its preparation method. The chemical element mass percentages of its components are: Cu: 18-23 wt.%; Ni: 3-8 wt.%; Fe: 1-3 wt.%; Zn: 20-25 wt.%; with the balance being Mn and other unavoidable impurities. This high-entropy manganese-based alloy exhibits high damping performance in a high-temperature range of 400℃ to 700℃, making it suitable for vibration and noise control under complex, high-temperature conditions. However, the working environment of high-temperature components is generally very harsh, not only bearing certain stresses but also often exposed to oxidizing environments, especially above 700℃, where this MnCuNiFeZn damping alloy will undergo severe oxidation. For the design and development of high-temperature damping alloys, it is not only necessary to meet the high damping performance at high temperatures but also to significantly improve the alloy's oxidation resistance. In addition, most manganese copper-nickel damping alloys contain Zn. When the Zn content is low, such as when the Zn content in the manganese copper-nickel alloy is no more than 10%, the alloy liquid has good fluidity. However, when the Zn content is high, it will affect the intermetallic compounds or the second phase, increase the viscosity of the alloy liquid and reduce its fluidity, thereby affecting the ability of the metal liquid to fill the mold.

[0004] Patent application CN202411133207.6 discloses a high-temperature oxidation-resistant damping alloy with the following chemical element mass percentage composition: Cu: 13-17 wt.%; Ni: 8-15 wt.%; Cr: 8-13 wt.%; Fe: 2-6 wt.%; Zn: 3-9 wt.%; Mo: 2-5 wt.%; Al: 0.5-3 wt.%; with the balance being Mn and other unavoidable impurities. This alloy exhibits not only high damping performance in the high-temperature range of 600-1000℃ but also excellent high-temperature oxidation resistance. However, the high content of elements such as Cr and Mo in the alloy results in high alloy cost. Furthermore, the presence of Mo in the alloy, with its high melting point (2622℃), increases its surface tension in the molten state, affecting the fluidity of the molten metal to some extent. This can lead to internal defects such as cracks during solidification of the damped alloy. Additionally, the mixing enthalpy between Cr and Mo, and between Mo and Ni, are both negative, indicating strong interactions between them. These interactions can form solid solutions, intermetallic compounds, or introduce solute elements. If molybdenum forms a solid solution or intermetallic compound with the matrix, it may affect the solidification point by altering the lattice constant, interatomic bonding forces, and phase transition temperature, potentially raising the solidification point of the alloy. The addition of Cr further increases the solidification point of the alloy, narrowing the temperature window during casting and solidification, reducing fluidity, and even causing premature loss of fluidity during solidification. This can result in defects such as shrinkage cavities or porosity in the casting, affecting its ability to fill the mold and the quality of the casting.

[0005] Thin-walled high-temperature damping alloy pipe fittings have wide applications in aerospace, energy, and other fields. Their quality and performance directly affect the operational reliability and service life of related equipment. Thin-walled pipe fittings with a wall thickness ≤2mm are prone to deformation and insufficient strength at high temperatures, and conventional alloys cannot simultaneously achieve vibration damping and high-temperature stability. Due to the wide variety of shapes and specifications of thin-walled high-temperature damping alloy pipe fittings, machining and forging are difficult. Many thin-walled high-temperature damping alloy pipe fittings require integral casting or near-net-shape manufacturing. Therefore, it is necessary to reduce and eliminate internal and surface defects during the casting process to ensure casting quality. Currently, there are still many problems in the manufacturing process of thin-walled high-temperature damping alloy pipe fittings. For example, the fluidity of the alloy liquid needs to be carefully considered during the casting process, as this directly affects the quality of the formed casting. Existing gating systems make it difficult to precisely control the flow state of the alloy liquid during the filling process, leading to defects such as incomplete filling and cold shuts in the pipe fittings. Moreover, due to the rapid heat dissipation of thin-walled pipe fittings, stress concentration is prone to occur during solidification, leading to cracking and a high scrap rate. Furthermore, existing manufacturing methods cannot adequately meet the special requirements of thin-walled high-temperature damping alloy pipe fittings for microstructure and performance, resulting in unstable high-temperature damping performance of the fittings and an inability to meet the growing engineering demands.

[0006] Therefore, developing a thin-walled high-temperature damping alloy pipe fitting, gating system, and manufacturing method that can effectively solve the above problems is of great practical significance. Summary of the Invention

[0007] To address the problems in existing technologies, particularly those related to incomplete casting, cold shuts, cracking, and unstable high-temperature damping performance in the manufacturing process of thin-walled high-temperature damping alloy tubing, and to meet the demand for developing high-quality alloy castings with compatible composition and processes, this invention aims to overcome the shortcomings of existing technologies and provide a thin-walled high-temperature damping alloy tubing, its preparation method, and gating system. This invention optimizes the alloy composition, increases the filling capacity of the alloy liquid, and ensures that all performance indicators of the thin-walled high-temperature damping alloy tubing meet design requirements, with good surface quality and no obvious defects. This allows the thin-walled high-temperature damping alloy tubing to be widely used in aerospace, automotive, shipbuilding, and high-precision instrument manufacturing fields.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0009] A thin-walled high-temperature damping alloy pipe fitting, wherein the chemical element mass percentage of the high-temperature damping alloy components is: Cu: 13-17 wt.%; Ni: 8-15 wt.%; Fe: 2-6 wt.%; Zn: 3-9 wt.%; Al: 0.5-3 wt.%; with the balance being Mn and other unavoidable impurities. Raw materials are weighed according to the component ratio of the high-temperature damping alloy, melted under vacuum or inert gas atmosphere, and then held at 1400-1600℃ to fully melt the raw materials and form an alloy liquid. The alloy liquid is then cast to obtain the thin-walled high-temperature damping alloy pipe fitting.

[0010] As a preferred technical solution of the present invention, the pipe fitting is a thin-walled pipe fitting with a wall thickness of ≤2mm, and the pipe fitting is at least one of straight pipe, bend pipe, reducer pipe and other special-shaped pipe fittings.

[0011] As a preferred technical solution of the present invention, the high-temperature damping alloy matrix of the pipe fitting has an fcc single-phase structure.

[0012] As a preferred technical solution of the present invention, when preparing high-temperature damping alloy, the raw materials are placed in a crucible according to the mass percentage and melted in a vacuum induction melting furnace. During the melting process, an argon protective atmosphere is introduced, and the temperature is held at 1400-1600°C to ensure that the raw materials are fully melted to form an alloy liquid. The alloy liquid is then cast to obtain the pipe fitting.

[0013] The high-temperature damping alloy of this invention is free of Cr and Mo. The roles and proportions of each element in the alloy of this invention are based on the following:

[0014] Manganese (Mn) is a major element constituting the crystal lattice of the high-temperature fcc phase. Its content in the alloy directly affects the stability of the phase and the service temperature range. Excessive Mn content can degrade melting and casting performance. When the Mn content exceeds 73.5 wt.%, further increases will lead to reduced fluidity of the alloy molten metal. Furthermore, increased Mn content widens the solidification temperature range, causing the alloy to transition from layered solidification to volumetric solidification, resulting in poorer feeding effects and reduced filling capacity of the molten alloy, thus affecting the quality of the casting. When the manganese content is too low, below 50 wt.%, damping performance decreases. A balance must be found between damping performance and fluidity when designing the alloy composition; a content of 50-73.5 wt.% is preferable.

[0015] Cu and Mn are completely dissolved, stabilizing the fcc phase structure and improving the alloy's high-temperature damping performance and service stability. In the solid solution state, copper undergoes a crystal structure transformation with temperature changes, generating numerous crystal interfaces. During interface movement, it absorbs significant vibrational energy. At lower copper contents, the effect on the alloy's fluidity is minimal; it may even improve fluidity by lowering the melting point or improving wettability. However, as the copper content increases, the alloy's solidification range may widen, leading to decreased fluidity. When the copper content exceeds 17 wt.%, the alloy's fluidity decreases significantly. This effect is not linear but rather has an optimal content range. This invention preferably uses a copper content of 13-17 wt.%.

[0016] Ni: Completely dissolved in the fcc lattice, stabilizing the fcc lattice, improving the strength and toughness of the alloy, and enhancing its high-temperature damping and oxidation resistance. Too low or too high a nickel content will prevent the formation of multiple phase structures during solidification and separation. Higher nickel content reduces fluidity; when the nickel content exceeds 15 wt.%, the surface tension of the alloy liquid increases, further reducing fluidity. This invention preferably uses a nickel content of 8-15 wt.%.

[0017] Fe: Completely dissolved in the fcc phase, it improves the strength of the alloy. When the Fe content is too high, the damping performance deteriorates, and when it is too low, the mechanical properties decrease. The present invention preferably uses a Fe content of 2-6 wt.%.

[0018] Zinc (Zn): Dissolved in the Mn matrix, zinc promotes the formation of manganese-rich regions and increases the squareness and number of fcc lattice points in the alloy, thus improving the high-temperature damping performance of the alloy. Zinc is also a strengthening element, increasing the alloy's strength. Furthermore, zinc increases the alloy's service temperature and reduces the attenuation of its damping capacity at high temperatures. Excessive zinc content increases smelting difficulty, while insufficient content fails to achieve the desired effect. Therefore, this invention recommends a zinc content of 3-9 wt.%.

[0019] Al (Al): A traditional deoxidizing and nitrogen-fixing element, beneficial for improving resistance to high-temperature oxidation. Aluminum can increase the strength of manganese-copper alloys and improve casting performance. Due to the significant difference between the atomic radii of aluminum and copper, aluminum dissolves into the matrix, causing greater lattice distortion and internal stress, making it easier to form twins and improving the damping performance of the alloy. In this invention, the content should be controlled within 0.5–3.0 wt.%. The addition of Al can improve the casting performance of the alloy, but when the Al content exceeds a certain range, such as exceeding 3.0 wt%, aluminum will exist in the form of particles, not firmly bonded to the matrix, leading to a decrease in mechanical properties and potentially adversely affecting the alloy's fluidity.

[0020] A method for preparing the thin-walled high-temperature damping alloy tubular component according to claim 1, comprising the following steps:

[0021] a. Mold preparation: Manufacture the mold, set up the gating system channels and venting channels, install the detachable core, and form the gating system;

[0022] b. Alloy melting: Using a vacuum induction melting furnace, the raw materials are weighed according to the chemical element mass percentages of the components of the target high-temperature damping alloy. The alloy is melted in a vacuum environment or an inert gas protective atmosphere, with the melting temperature set at 1400-1600℃ and the melting time controlled to obtain a molten alloy. Preferably, this invention selects high-quality raw materials for melting according to the predetermined alloy composition; a vacuum induction melting furnace is used to melt in a high vacuum environment to reduce the gas and impurity content in the alloy; during the melting process, the melting temperature and time are strictly controlled to ensure uniform alloy composition; and preferably, the molten alloy is refined to further improve the purity and quality of the alloy.

[0023] c. Casting process: Using the casting system, the mold is preheated. Under vacuum or inert gas atmosphere, the molten alloy is poured into the pouring cup, allowing it to enter the mold cavity through the casting system. The casting flow rate and speed are controlled, and the casting temperature is monitored to ensure the molten alloy fills the cavity smoothly. Preferably, the thin-walled high-temperature damping alloy that has been melted and refined is heated to a suitable casting temperature and then poured into the pouring cup, allowing it to enter the mold cavity. During the casting process, the casting speed and temperature are carefully controlled to ensure the molten alloy fills the cavity smoothly and achieves a good solidification structure.

[0024] d. Cooling, demolding and post-processing: After casting, allow the mold to cool and demold after the alloy liquid has completely solidified; then perform post-processing on the demolded thin-walled tube casting to obtain the tube fitting; preferably, perform post-processing processes such as cleaning, grinding and heat treatment on the casting to remove burrs, flash and oxide scale on the surface of the casting, and improve the dimensional accuracy and performance of the casting.

[0025] e. Quality Inspection: Inspect the quality of pipe fittings to obtain qualified thin-walled high-temperature damping alloy pipe fitting products.

[0026] As a preferred technical solution of the present invention, in step b, the holding time during alloy smelting shall not exceed 60 minutes.

[0027] As a preferred technical solution of the present invention, in step c, when preheating the mold, the preheating temperature of the mold is 900-1000℃.

[0028] As a preferred technical solution of the present invention, in step c, when pouring the alloy liquid, the pouring temperature of the alloy liquid is controlled to be 1530-1550℃.

[0029] As a preferred technical solution of the present invention, in step c, when pouring the alloy liquid, the pouring speed is controlled to be no higher than 5L / min.

[0030] As a preferred technical solution of the present invention, in step d, when cooling and demolding are performed, demolding is performed when the casting is cooled to no higher than 200°C.

[0031] A casting system for preparing the thin-walled high-temperature damping alloy tube of the present invention is prepared using silica sol and zirconium dioxide. The casting system is used to prepare the thin-walled high-temperature damping alloy tube in a vacuum environment or an inert gas protective atmosphere. The casting system includes a pouring cup, a sprue, a runner, an ingate, and an venting channel.

[0032] The pouring cup is funnel-shaped and is used to receive molten alloy from the ladle; the inner wall of the pouring cup is provided with a smooth surface coated with graphene.

[0033] The sprue is a vertical channel with a circular cross-section. The sprue is connected to the bottom of the pouring cup and guides the molten alloy in the pouring cup vertically to the horizontal runner. Spiral guide vanes are installed inside the sprue.

[0034] The horizontal sprue has a trapezoidal or rectangular cross-section. A trapezoidal horizontal sprue has a wider bottom than top, while a rectangular horizontal sprue has the same width at both the bottom and top. The horizontal sprue is located below the sprue and is vertically connected to it. Multiple ingates are evenly distributed below the horizontal sprue. The horizontal sprue guides the smooth flow and rapid distribution of the molten alloy. A slag collection bag is provided at the end of the horizontal sprue to collect impurities and slag from the molten alloy.

[0035] The ingate is flat and each ingate is connected to the tube cavity. The molten alloy in the runner enters the tube cavity through the ingate. The width of the ingate is adjusted according to the tube wall thickness, and the number and position of the ingates are arranged according to the tube structure.

[0036] Multiple exhaust channels are provided on the top and sides of the tube cavity to allow the exhaust channels to communicate with the atmosphere; a filter device is provided at the inlet of the exhaust channel.

[0037] As a preferred technical solution of the present invention, the cross-sectional shape of the exhaust duct is circular or rectangular, and the cross-sectional diameter or width of the exhaust duct is set according to the volume of the pipe cavity and the gas discharge volume.

[0038] As a preferred embodiment of the present invention, the ratio of the diameter of the top opening of the pouring cup to the diameter of its bottom opening is 1.27:1.

[0039] As a preferred embodiment of the present invention, the diameter of the direct casting channel is no greater than 83mm.

[0040] As a preferred technical solution of the present invention, the exhaust channel is also connected to the pouring cup or the sprue, and more branch exhaust channels are provided so that the gas in the cavity of the tube can be discharged more smoothly.

[0041] The casting system used in this invention to prepare thin-walled high-temperature damping alloy pipe fittings includes:

[0042] 1) Pour cup: It is funnel-shaped with a larger opening at the top and a smaller opening at the bottom. It is used to receive the high-temperature alloy liquid from the ladle and to provide initial buffering and flow stabilization for the alloy liquid. Preferably, the inner wall is coated with a high-temperature resistant and low-friction graphene coating to reduce the resistance and heat loss when the alloy liquid flows.

[0043] 2) Sprue: A vertical channel with a circular cross-section, the diameter of which is designed according to the size of the pipe fitting and the pouring flow rate; the sprue is connected to the bottom of the pouring cup and guides the molten alloy in the pouring cup vertically to the runner; the sprue is equipped with spiral guide vanes inside, which make the molten alloy rotate during the flow process, enhancing its fluidity and filling capacity.

[0044] 3) Horizontal runner: It is set horizontally and connected vertically to the sprue; the horizontal runner adopts a trapezoidal cross section, and its bottom width is greater than its top width, which is conducive to the smooth flow and rapid distribution of the alloy liquid; multiple ingates are evenly distributed on the horizontal runner, and a slag collection bag is set at the end of the horizontal runner to collect impurities and slag in the alloy liquid.

[0045] 4) Ingate: Connected to the cavity of the pipe fitting, it is the key channel for the molten alloy to enter the cavity; the shape of the ingate is flat, and its width is adjusted according to the wall thickness of the pipe fitting to ensure that the molten alloy can fill the cavity evenly and quickly; the number and position of the ingate are optimized according to the structural characteristics of the pipe fitting to ensure that all parts of the cavity can be fully filled.

[0046] 5) Exhaust ducts: Multiple exhaust ducts are provided on the top and sides of the tube cavity, and the exhaust ducts are open to the atmosphere; the cross-sectional shape of the exhaust duct is circular or rectangular, and its diameter or width is designed according to the volume of the cavity and the gas discharge volume; a filter device is provided at the inlet of the exhaust duct to prevent the alloy liquid from entering the exhaust duct, while ensuring that the gas in the cavity can be discharged smoothly.

[0047] This invention designs a casting system, including the following:

[0048] 1) Mold Design and Manufacturing: Based on the shape, size, and structural characteristics of the thin-walled high-temperature damping alloy pipe fittings, design and manufacture the corresponding molds. The molds must have high precision and surface quality to ensure the forming accuracy and surface quality of the pipe fittings. Simultaneously, the heat dissipation performance and thermal stability of the molds must be considered to meet the requirements of high-temperature casting.

[0049] 2) Wax Model Making: Using the lost-wax casting method in precision casting, molten wax is poured into a mold, and after cooling, a wax model is formed. The wax model should have good surface finish and dimensional accuracy to ensure the smooth progress of subsequent processes.

[0050] 3) Shell Formation: Immerse the wax model in a slurry composed of refractory material and binder, ensuring the surface of the wax model is evenly covered with a layer of slurry. Then, sprinkle a layer of refractory sand on its surface. After the slurry dries, repeat the above steps until a shell of a certain thickness is formed. The shell must have sufficient strength and high-temperature resistance to withstand the high temperatures and pressures during the casting process.

[0051] 4) Dewaxing: Place the wax model with the shell inside into hot water or steam to melt the wax and allow it to flow out of the shell, resulting in a hollow shell. The dewaxing process requires careful control of temperature and time to ensure that the wax model melts completely while avoiding damage to the shell.

[0052] Compared with the prior art, the present invention has the following obvious and prominent substantive features and significant advantages:

[0053] 1. This invention achieves high quality and high performance by matching the alloy liquid composition, the molded parts and their preparation process, and the casting equipment. When designing the alloy composition, a balance must be found between damping performance and fluidity. This invention manufactures high-quality and high-performance thin-walled high-temperature damping alloy pipes, which are widely used in aerospace, automotive, shipbuilding and high-precision instrument manufacturing and other fields. They effectively absorb and dissipate the vibration energy caused by external forces, thereby reducing noise, reducing mechanical fatigue and extending the service life of equipment.

[0054] 2. This invention improves the quality of castings by casting in a vacuum environment, which effectively reduces the reaction between the molten alloy and air, reduces the generation of impurities and porosity, and improves the purity and performance of the castings.

[0055] 3. This invention improves the filling quality. The gating system of this invention, through the rational design of the structure and size of the gating cup, sprue, runner, ingate and venting channel, enables the alloy liquid to fill the cavity of the pipe fitting smoothly and quickly, effectively avoiding defects such as incomplete filling and cold shut, and improving the forming quality of the pipe fitting.

[0056] 4. This invention reduces stress concentration and cracking. By rationally designing the gating system, it can effectively compensate for the volume shrinkage during the solidification of the alloy liquid, reduce defects such as shrinkage cavities and porosity, and at the same time reduce stress concentration inside the casting, avoid pipe cracking, and improve the product qualification rate.

[0057] This invention improves production efficiency and reduces costs. The manufacturing method of this invention is simple to operate and easy to control, which can improve production efficiency and reduce production costs. At the same time, by reducing the scrap rate, it improves resource utilization and has good economic and social benefits. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the casting system for thin-walled high-temperature damping alloy pipe fittings in Embodiment 1 of the present invention.

[0059] Figure 2 This is a schematic flowchart of a preferred embodiment of the manufacturing method of the present invention.

[0060] Figure 3 This is a schematic diagram of the casting system for thin-walled high-temperature damping alloy pipe fittings in Embodiment 2 of the present invention.

[0061] Figure 4 The image shows the XRD pattern of the wall material of the thin-walled high-temperature damping alloy pipe fitting in Embodiment 1 of the present invention.

[0062] exist Figure 1 and Figure 3 In the attached diagram, the labels are: 1-sprue cup, 2-sprue, 3-runner, 4-ingate, 5-venting channel, 6-pipe cavity, 7-breathable material. Detailed Implementation

[0063] To better understand the present invention, the following embodiments are further illustrations of the present invention, but the content of the present invention is not limited to the following embodiments.

[0064] The high-temperature damping alloy of this invention is free of Cr and Mo. The roles and proportions of each element in the alloy in the following embodiments are based on the following:

[0065] Manganese (Mn) is a major element constituting the crystal lattice of the high-temperature fcc phase. Its content in the alloy directly affects the stability of the phase and the service temperature range. Excessive Mn content can degrade melting and casting performance. When the Mn content exceeds 73.5 wt.%, further increases will lead to reduced fluidity of the alloy molten metal. Furthermore, increased Mn content widens the solidification temperature range, causing the alloy to transition from layered solidification to volumetric solidification, resulting in poorer feeding effects and reduced filling capacity of the molten alloy, thus affecting the quality of the casting. When the manganese content is too low, below 50 wt.%, damping performance decreases. A balance must be found between damping performance and fluidity when designing the alloy composition; a content of 50-73.5 wt.% is preferable.

[0066] Cu and Mn are completely dissolved, stabilizing the fcc phase structure and improving the alloy's high-temperature damping performance and service stability. In the solid solution state, copper undergoes a crystal structure transformation with temperature changes, generating numerous crystal interfaces. During interface movement, it absorbs significant vibrational energy. At lower copper contents, the effect on the alloy's fluidity is minimal; it may even improve fluidity by lowering the melting point or improving wettability. However, as the copper content increases, the alloy's solidification range may widen, leading to decreased fluidity. When the copper content exceeds 17 wt.%, the alloy's fluidity decreases significantly. This effect is not linear but rather has an optimal content range. This invention preferably uses a copper content of 13-17 wt.%.

[0067] Ni: Completely dissolved in the fcc lattice, stabilizing the fcc lattice, improving the strength and toughness of the alloy, and enhancing its high-temperature damping and oxidation resistance. Too low or too high a nickel content will prevent the formation of multiple phase structures during solidification and separation. Higher nickel content reduces fluidity; when the nickel content exceeds 15 wt.%, the surface tension of the alloy liquid increases, further reducing fluidity. This invention preferably uses a nickel content of 8-15 wt.%.

[0068] Fe: Completely dissolved in the fcc phase, it improves the strength of the alloy. When the Fe content is too high, the damping performance deteriorates, and when it is too low, the mechanical properties decrease. The present invention preferably uses a Fe content of 2-6 wt.%.

[0069] Zinc (Zn): Dissolved in the Mn matrix, zinc promotes the formation of manganese-rich regions and increases the squareness and number of fcc lattice points in the alloy, thus improving the high-temperature damping performance of the alloy. Zinc is also a strengthening element, increasing the alloy's strength. Furthermore, zinc increases the alloy's service temperature and reduces the attenuation of its damping capacity at high temperatures. Excessive zinc content increases smelting difficulty, while insufficient content fails to achieve the desired effect. Therefore, this invention recommends a zinc content of 3-9 wt.%.

[0070] Al (Al): A traditional deoxidizing and nitrogen-fixing element, beneficial for improving resistance to high-temperature oxidation. Aluminum can increase the strength of manganese-copper alloys and improve casting performance. Due to the significant difference between the atomic radii of aluminum and copper, aluminum dissolves into the matrix, causing greater lattice distortion and internal stress, making it easier to form twins and improving the damping performance of the alloy. In this invention, the content should be controlled within 0.5–3.0 wt.%. The addition of Al can improve the casting performance of the alloy, but when the Al content exceeds a certain range, such as exceeding 3.0 wt%, aluminum will exist in the form of particles, not firmly bonded to the matrix, leading to a decrease in mechanical properties and potentially adversely affecting the alloy's fluidity.

[0071] The following embodiments of the present invention differ significantly from the patent technology of patent application number CN202411133207.6 in that they do not contain the metallic elements Cr and Mo, and the casting method used is different, resulting in different castings. Patent application number CN202411133207.6 discloses a high-temperature oxidation-resistant damping alloy that possesses not only high damping performance but also excellent high-temperature oxidation resistance in the high-temperature range of 600-1000℃. However, the alloy contains high levels of elements such as Cr and Mo, resulting in high alloy costs. Furthermore, the presence of Mo in the alloy, with its high melting point (2622℃), increases its surface tension in the molten state, affecting the fluidity of the molten metal to some extent. This can lead to internal defects such as cracks during solidification of the damped alloy. Additionally, the mixing enthalpy between Cr and Mo, and between Mo and Ni, are both negative, indicating strong interactions between them. These interactions can form solid solutions, intermetallic compounds, or introduce solute elements. If molybdenum forms a solid solution or intermetallic compound with the matrix, it may affect the solidification point by altering the lattice constant, interatomic bonding forces, and phase transition temperature, potentially raising the solidification point of the alloy. The addition of Cr further increases the solidification point of the alloy, narrowing the temperature window during casting and solidification, reducing fluidity, and even causing premature loss of fluidity during solidification. This can result in defects such as shrinkage cavities or porosity in the casting, affecting its ability to fill the mold and the quality of the casting.

[0072] The preferred embodiment of the present invention is a method for manufacturing high-temperature damping alloy pipe fittings, such as... Figure 2 As shown, it includes the following steps:

[0073] (1) Mold design and manufacturing: Based on the shape, size and structural characteristics of the thin-walled high-temperature damping alloy pipe fittings, design and manufacture the corresponding molds; the molds need to have high precision and surface quality to ensure the forming precision and surface quality of the pipe fittings; at the same time, the heat dissipation performance and thermal stability of the molds should be considered to meet the requirements of high-temperature casting.

[0074] (2) Wax model making: The lost-wax method in precision casting is used to inject molten wax into a mold and form a wax model after cooling. The wax model should have good surface finish and dimensional accuracy to ensure the smooth progress of subsequent processes.

[0075] (3) Shell making: Immerse the wax model in a slurry composed of refractory material and binder, so that the surface of the wax model is evenly covered with a layer of slurry, and then sprinkle a layer of refractory sand on its surface. After the slurry dries, repeat the above operation until a shell of a certain thickness is formed; the shell must have sufficient strength and high temperature resistance to withstand the high temperature and pressure during the casting process.

[0076] (4) Dewaxing: Place the wax model with the shell into hot water or steam to melt the wax model and let it flow out of the shell, thus obtaining a hollow shell; the temperature and time of the dewaxing process must be well controlled to ensure that the wax model melts completely and to avoid damage to the shell.

[0077] (5) Alloy smelting: Select high-quality raw materials for smelting according to the predetermined alloy composition; use a vacuum induction melting furnace to smelt in a high vacuum environment to reduce the content of gas and impurities in the alloy; strictly control the smelting temperature and time during the smelting process to ensure uniform alloy composition, and refine the alloy liquid to further improve the purity and quality of the alloy.

[0078] (6) Casting: The thin-walled high-temperature damping alloy liquid that has been melted and refined is heated to a suitable casting temperature and then poured into the pouring cup so that the alloy liquid enters the shell cavity through the gating system. During the casting process, the casting speed and casting temperature should be controlled to ensure that the alloy liquid can fill the cavity smoothly and obtain a good solidification structure.

[0079] (7) Cooling and demolding: After pouring, allow the mold shell to cool naturally or use an appropriate cooling method to accelerate cooling. After the alloy liquid has completely solidified, remove the mold shell to obtain the casting.

[0080] (8) Post-processing: Cleaning, grinding, heat treatment and other post-processing processes are carried out on the castings to remove burrs, flash and oxide scale on the surface of the castings and improve the dimensional accuracy and performance of the castings.

[0081] The present invention will be further described below with reference to the embodiments. The damping performance of the alloy obtained in the embodiments was tested by using a Gottfried gyroscope at a strain amplitude of 20 μm, and thin-walled tubes with a wall thickness of 1-2 mm were prepared.

[0082] When smelting alloys, the holding time should not exceed 60 minutes.

[0083] When preheating the mold, the preheating temperature is 900-1000℃.

[0084] When pouring the alloy liquid, the pouring temperature should be controlled at 1530-1550℃.

[0085] When pouring molten alloy, the pouring speed should be controlled to be no higher than 5L / min.

[0086] During cooling and demolding, demolding should be performed when the casting has cooled to a temperature not exceeding 200°C.

[0087] The above solution will be further described below with reference to specific embodiments. The preferred embodiments of the present invention are described in detail below:

[0088] Example 1

[0089] In this embodiment, a thin-walled high-temperature damping alloy pipe fitting is provided. The chemical element mass percentage of the high-temperature damping alloy components is as follows: Cu: 13 wt.%; Ni: 8 wt.%; Fe: 2 wt.%; Zn: 3 wt.%; Al: 0.5 wt.%; with the balance being Mn and other unavoidable impurities. The raw materials are weighed according to the component ratio of the high-temperature damping alloy, melted under vacuum conditions or inert gas protective atmosphere, and then held at 1400°C to fully melt the raw materials and form an alloy liquid. The alloy liquid is then cast to obtain the thin-walled high-temperature damping alloy pipe fitting.

[0090] The gating system used in this embodiment for preparing the thin-walled high-temperature damping alloy pipe fittings is as follows: Figure 1 As shown, the thin-walled high-temperature damping alloy pipe fittings are prepared using silica sol and zirconium dioxide. The gating system is used to prepare thin-walled high-temperature damping alloy pipe fittings in a vacuum environment or an inert gas protective atmosphere. The gating system includes a pouring cup 1, a sprue 2, a runner 3, an ingate 4, and an exhaust channel 5.

[0091] The pouring cup 1 is funnel-shaped and is used to receive the molten alloy from the ladle; the inner wall of the pouring cup 1 is provided with a smooth surface coated with graphene.

[0092] The sprue 2 is a vertical channel with a circular cross-section. The sprue 2 is connected to the bottom of the pouring cup 1 and guides the alloy liquid in the pouring cup 1 vertically to the horizontal sprue 3. The sprue 2 is equipped with spiral guide vanes.

[0093] The horizontal gating 3 has a rectangular cross-section, with the bottom width being the same as the top width. The horizontal gating 3 is located below the vertical gating 2 and is vertically connected to the vertical gating 2. The horizontal gating 3 guides the smooth flow and rapid distribution of the molten alloy. Multiple ingates 4 are evenly distributed below the horizontal gating 3. A slag collection bag is provided at the end of the horizontal gating 3 to collect impurities and slag in the molten alloy.

[0094] The ingate 4 is flat and each ingate 4 is connected to the pipe cavity 6. The molten alloy in the runner 3 enters the pipe cavity 6 through the ingate 4. The width of the ingate 4 is adjusted according to the pipe wall thickness, and the number and position of the ingate 4 are arranged according to the pipe structure.

[0095] Multiple exhaust channels 5 are provided on the top and sides of the tube cavity 6 to allow the exhaust channels 5 to communicate with the atmosphere; a filter device is provided at the inlet of the exhaust channel 5.

[0096] a. Alloy raw material preparation: Weigh the alloy raw materials according to the chemical element mass percentage of the components of the target high-temperature damping alloy. The chemical element mass percentage of the high-temperature damping alloy components is as follows: Cu: 13 wt.%; Ni: 8 wt.%; Fe: 2 wt.%; Zn: 3 wt.%; Al: 0.5 wt.%; with the balance being Mn and other unavoidable impurities.

[0097] b. Alloy melting: A vacuum induction melting furnace is used. The alloy raw materials are placed in a crucible and melted in the vacuum induction melting furnace. During the melting process, an argon protective atmosphere is introduced. The induction heating is carried out to 1400℃ and held for no more than 60 minutes to ensure that the raw materials are fully melted, ensuring that the alloy composition is uniform and obtaining an alloy liquid that meets the composition requirements.

[0098] c. Casting process: This includes gating system installation, mold preheating, and alloy liquid pouring, as detailed below:

[0099] c-1. Gating System Installation: Assemble the gating system by combining the pouring cup 1, sprue 2, runner 3, ingate 4, and venting channel 5, thus completing the mold installation. Figure 1 As shown, it is installed on the mold; ensuring that the connection between each component is tight and there is no leakage; the gating system can effectively vent, reduce stress concentration at the bends of the pipes, greatly reduce the probability of cracks and pores, and effectively improve the overall quality and service life of the pipes. The outlet of the venting channel 5 is provided with a breathable material 7 to separate the inside and outside of the venting channel 5; this embodiment manufactures a high-precision mold, sets up the gating system channel and the venting channel 5, and installs a detachable core to form the gating system;

[0100] c-2. Mold preheating: Place the assembled mold into a heating furnace and preheat it to 1000℃ to reduce the temperature difference between the molten alloy and the mold and avoid cracking of the casting.

[0101] c-3. Alloy liquid pouring: Under vacuum conditions, the alloy liquid pouring temperature is controlled at 1550℃. The alloy liquid prepared in step b is poured into the pouring cup 1, so that the alloy liquid enters the tube cavity 6 through the pouring system. During the pouring process, the pouring speed is controlled at 5L / min to ensure that the alloy liquid fills the cavity smoothly.

[0102] d. Cooling, demolding and post-processing: After casting, the mold is naturally cooled in the furnace. After the alloy liquid has completely solidified, when the casting has cooled to no more than 200°C, the demolding operation is carried out. Then the thin-walled tube casting is post-processed, including cleaning and heat treatment, to obtain a tube with a wall thickness of 1.5mm.

[0103] e. Quality Inspection: Inspect the quality of pipe fittings to obtain qualified thin-walled high-temperature damping alloy pipe fitting products.

[0104] Experimental Test Analysis

[0105] Experimental testing and analysis were conducted on thin-walled high-temperature damping alloy tubing. In this embodiment, samples of the high-temperature damping alloy tubing were cut and tested for microscopic observation. The high-temperature damping alloy material in this embodiment has an fcc single-phase structure. Figure 4 As shown. The internal friction is 0.01-0.04 in the temperature range of 400-800℃. Testing revealed that all performance indicators of this thin-walled high-temperature damping alloy pipe fitting meet design requirements, with good surface quality and no obvious defects.

[0106] Example 2

[0107] This embodiment is basically the same as Embodiment 1, except that:

[0108] In this embodiment, a thin-walled high-temperature damping alloy pipe fitting is provided. The chemical element mass percentage of the high-temperature damping alloy components is as follows: Cu: 17 wt.%; Ni: 15 wt.%; Fe: 6 wt.%; Zn: 9 wt.%; Al: 3 wt.%; with the balance being Mn and other unavoidable impurities. The raw materials are weighed according to the component ratio of the high-temperature damping alloy, melted under vacuum or inert gas atmosphere, and then held at 1600°C to fully melt the raw materials and form an alloy liquid. The alloy liquid is then cast to obtain the thin-walled high-temperature damping alloy pipe fitting.

[0109] The gating system used in this embodiment for preparing the thin-walled high-temperature damping alloy pipe fittings is as follows: Figure 3 As shown, thin-walled high-temperature damping alloy tubes are prepared using silica sol and zirconium dioxide. The gating system is used to prepare these tubes in a vacuum environment or an inert gas protective atmosphere. The venting channel 5 is also connected to the pouring cup 1 or the sprue 2, providing more branched venting channels to allow for smoother gas discharge from the tube cavity 6. This gating system can effectively compensate for shrinkage during solidification, effectively increasing the filling speed of the alloy liquid. Simultaneously, the optimized layout and increased number of venting channels ensure smoother gas discharge from the cavity.

[0110] In this embodiment, a method for preparing a thin-walled high-temperature damping alloy tube includes the following steps:

[0111] a. Alloy raw material preparation: Weigh the alloy raw materials according to the chemical element mass percentage of the components of the target high-temperature damping alloy. The chemical element mass percentage of the high-temperature damping alloy components is as follows: Cu: 17 wt.%; Ni: 15 wt.%; Fe: 6 wt.%; Zn: 6 wt.%; Al: 3 wt.%; with the balance being Mn and other unavoidable impurities.

[0112] b. Alloy melting: A vacuum induction melting furnace is used. The alloy raw materials are placed in a crucible and melted in the vacuum induction melting furnace. During the melting process, an argon protective atmosphere is introduced. The induction heating is carried out to 1600℃ and held for no more than 60 minutes to ensure that the raw materials are fully melted, ensuring that the alloy composition is uniform and obtaining an alloy liquid that meets the composition requirements.

[0113] c. Casting process: This includes gating system installation, mold preheating, and alloy liquid pouring, as detailed below:

[0114] c-1. Gating System Installation: Assemble the gating system by combining the pouring cup 1, sprue 2, runner 3, ingate 4, and venting channel 5, thus completing the mold installation. Figure 3 As shown, it is installed on the mold; this embodiment adjusts some structures of the gating system, such as... Figure 3 As shown, the venting channel 5 is also connected to the pouring cup 1 and the sprue 2, and more branch venting channels are provided to maintain the air pressure balance between the pouring cup 1, the sprue 2, and the venting channel 5. This gating system can effectively compensate for the shrinkage of the pipe during the solidification process, effectively improve the filling speed of the alloy liquid, and effectively improve the overall quality and service life of the pipe. At the same time, the layout of the venting channels is optimized and the number of venting channels is increased to ensure that the gas in the cavity can be discharged more smoothly. In this embodiment, a high-precision mold is manufactured, and the gating system channels and venting channels 5 are set, and a detachable core is installed to form the gating system.

[0115] c-2. Mold preheating: Place the assembled mold into a heating furnace and preheat it to 900℃ to reduce the temperature difference between the molten alloy and the mold and avoid cracking of the casting.

[0116] c-3. Alloy liquid pouring: Under vacuum conditions, the alloy liquid pouring temperature is controlled at 1530℃. The alloy liquid prepared in step b is poured into the pouring cup 1, so that the alloy liquid enters the tube cavity 6 through the pouring system. During the pouring process, the pouring speed is controlled at 5L / min to ensure that the alloy liquid fills the cavity smoothly.

[0117] d. Cooling, demolding and post-processing: After casting, the mold is naturally cooled in the furnace. After the alloy liquid has completely solidified, when the casting has cooled to no more than 200°C, the demolding operation is carried out. Then the thin-walled tube casting is post-processed, including cleaning and heat treatment, to obtain a tube with a wall thickness of 2mm.

[0118] e. Quality Inspection: Inspect the quality of pipe fittings to obtain qualified thin-walled high-temperature damping alloy pipe fitting products.

[0119] Experimental Test Analysis

[0120] Experimental testing and analysis were conducted on thin-walled high-temperature damping alloy tubing. Samples of the high-temperature damping alloy tubing in this embodiment were cut and tested for microscopic observation. The high-temperature damping alloy material in this embodiment has an fcc single-phase structure. The internal friction is 0.02-0.05 in the temperature range of 400-800℃. The results show that by optimizing the gating system parameters, the filling effect of the tubing is better, internal defects are further reduced, and the high-temperature damping performance is significantly improved.

[0121] Based on the 1-2 mm wall thickness thin-walled pipes in Examples 1-2 above, it is evident that the casting of thin-walled high-temperature damping alloy pipes requires high fluidity of the alloy liquid. The content of elements such as Cr and Mo, which may reduce the fluidity of the alloy liquid, should be reduced or eliminated from the alloy liquid composition. To improve casting quality, the above embodiments involve casting in a vacuum environment, effectively reducing the reaction between the alloy liquid and air, lowering the generation of impurities and porosity, and improving the purity and performance of the castings. To improve filling quality: The gating system of the above embodiments of the present invention, through reasonable design of the structure and dimensions of the pouring cup, sprue, runner, ingate, and venting channel, enables the alloy liquid to fill the pipe cavity smoothly and quickly, effectively avoiding defects such as incomplete filling and cold shuts, thus improving the forming quality of the pipes. To reduce stress concentration and cracking in thin-walled damping alloy pipes: By reasonably designing the gating system, the volume shrinkage during solidification of the alloy liquid can be effectively compensated, reducing defects such as shrinkage cavities and porosity, while simultaneously reducing stress concentration inside the casting, preventing pipe cracking, and improving the product qualification rate. To improve production efficiency and reduce costs: The manufacturing method of the above embodiments of the present invention is simple to operate, and includes necessary temperature and pressure compensation to maintain the balance and stability of temperature and pressure during melting and casting, which is beneficial for solute homogenization and diffusion and grain refinement. Furthermore, the manufacturing method of the above embodiments of the present invention is easy to control, thereby improving production efficiency and reducing production costs. Simultaneously, by reducing the scrap rate, resource utilization is improved, resulting in good economic and social benefits.

[0122] Example 3

[0123] This embodiment is basically the same as the above embodiments, except that:

[0124] In this embodiment, a thin-walled high-temperature damping alloy pipe fitting is provided. The chemical element mass percentage of the high-temperature damping alloy components is as follows: Cu: 16 wt.%; Ni: 13 wt.%; Fe: 4 wt.%; Zn: 6 wt.%; Al: 2 wt.%; with the balance being Mn and other unavoidable impurities. The raw materials are weighed according to the component ratio of the high-temperature damping alloy, melted under vacuum or inert gas atmosphere, and then held at 1550°C to fully melt the raw materials and form an alloy liquid. The alloy liquid is then cast to obtain the thin-walled high-temperature damping alloy pipe fitting.

[0125] The gating system used in this embodiment for preparing the thin-walled high-temperature damping alloy pipe fittings is as follows: Figure 3 As shown, thin-walled high-temperature damping alloy tubes are prepared using silica sol and zirconium dioxide. The gating system is used to prepare these tubes in a vacuum environment or an inert gas protective atmosphere. The venting channel 5 is also connected to the pouring cup 1 or the sprue 2, providing more branched venting channels to allow for smoother gas discharge from the tube cavity 6. This gating system can effectively compensate for shrinkage during solidification, effectively increasing the filling speed of the alloy liquid. Simultaneously, the optimized layout and increased number of venting channels ensure smoother gas discharge from the cavity.

[0126] In this embodiment, a method for preparing a thin-walled high-temperature damping alloy tube includes the following steps:

[0127] a. Alloy raw material preparation: Weigh the alloy raw materials according to the chemical element mass percentage of the components of the target high-temperature damping alloy. The chemical element mass percentage of the high-temperature damping alloy components is as follows: Cu: 17 wt.%; Ni: 15 wt.%; Fe: 6 wt.%; Zn: 6 wt.%; Al: 3 wt.%; with the balance being Mn and other unavoidable impurities.

[0128] b. Alloy melting: A vacuum induction melting furnace is used. The alloy raw materials are placed in a crucible and melted in the vacuum induction melting furnace. During the melting process, an argon protective atmosphere is introduced. The induction heating is carried out to 1550℃ and held for no more than 60 minutes to ensure that the raw materials are fully melted, ensuring that the alloy composition is uniform and obtaining an alloy liquid that meets the composition requirements.

[0129] c. Casting process: This includes gating system installation, mold preheating, and alloy liquid pouring, as detailed below:

[0130] c-1. Gating System Installation: Assemble the gating system by combining the pouring cup 1, sprue 2, runner 3, ingate 4, and venting channel 5, thus completing the mold installation. Figure 3 As shown, it is installed on the mold; this embodiment adjusts some structures of the gating system, such as... Figure 3As shown, the venting channel 5 is also connected to the pouring cup 1 and the sprue 2, and more branch venting channels are provided to maintain the air pressure balance between the pouring cup 1, the sprue 2, and the venting channel 5. This gating system can effectively compensate for the shrinkage of the pipe during the solidification process, effectively improve the filling speed of the alloy liquid, and effectively improve the overall quality and service life of the pipe. At the same time, the layout of the venting channels is optimized and the number of venting channels is increased to ensure that the gas in the cavity can be discharged more smoothly. In this embodiment, a high-precision mold is manufactured, and the gating system channels and venting channels 5 are set, and a detachable core is installed to form the gating system.

[0131] c-2. Mold preheating: Place the assembled mold into a heating furnace and preheat it to 960℃ to reduce the temperature difference between the molten alloy and the mold and avoid cracking of the casting.

[0132] c-3. Alloy liquid pouring: Under vacuum conditions, the alloy liquid pouring temperature is controlled at 1540℃. The alloy liquid prepared in step b is poured into the pouring cup 1, so that the alloy liquid enters the tube cavity 6 through the pouring system. During the pouring process, the pouring speed is controlled at 4L / min to ensure that the alloy liquid fills the cavity smoothly.

[0133] d. Cooling, demolding and post-processing: After casting, the mold is naturally cooled in the furnace. After the alloy liquid has completely solidified, when the casting has cooled to no more than 200°C, the demolding operation is carried out. Then the thin-walled tube casting is post-processed, including cleaning and heat treatment, to obtain a tube with a wall thickness of 1.8mm.

[0134] e. Quality Inspection: Inspect the quality of pipe fittings to obtain qualified thin-walled high-temperature damping alloy pipe fitting products.

[0135] Experimental Test Analysis

[0136] Experimental testing and analysis were conducted on the thin-walled high-temperature damping alloy tubing. Samples of the tubing were cut and tested for microscopic observation. The high-temperature damping alloy material in this embodiment has an FCC single-phase structure. The internal friction is 0.015-0.036 within the temperature range of 400-800℃. Testing showed that all performance indicators of the thin-walled high-temperature damping alloy tubing met the design requirements, and the surface quality was good with no obvious defects.

[0137] Example 4

[0138] This embodiment is basically the same as the above embodiments, except that:

[0139] In this embodiment, a thin-walled high-temperature damping alloy pipe fitting is provided. The chemical element mass percentage of the high-temperature damping alloy components is as follows: Cu: 14 wt.%; Ni: 10 wt.%; Fe: 3 wt.%; Zn: 4 wt.%; Al: 1.5 wt.%; with the balance being Mn and other unavoidable impurities. The raw materials are weighed according to the component ratio of the high-temperature damping alloy, melted under vacuum conditions or inert gas protective atmosphere, and then held at 1550°C to fully melt the raw materials and form an alloy liquid. The alloy liquid is then cast to obtain the thin-walled high-temperature damping alloy pipe fitting.

[0140] The gating system used in this embodiment for preparing the thin-walled high-temperature damping alloy pipe fittings is as follows: Figure 3 As shown, thin-walled high-temperature damping alloy tubes are prepared using silica sol and zirconium dioxide. The gating system is used to prepare these tubes in a vacuum environment or an inert gas protective atmosphere. The venting channel 5 is also connected to the pouring cup 1 or the sprue 2, providing more branched venting channels to allow for smoother gas discharge from the tube cavity 6. This gating system can effectively compensate for shrinkage during solidification, effectively increasing the filling speed of the alloy liquid. Simultaneously, the optimized layout and increased number of venting channels ensure smoother gas discharge from the cavity.

[0141] In this embodiment, a method for preparing a thin-walled high-temperature damping alloy tube includes the following steps:

[0142] a. Alloy raw material preparation: Weigh the alloy raw materials according to the chemical element mass percentage of the components of the target high-temperature damping alloy. The chemical element mass percentage of the high-temperature damping alloy components is as follows: Cu: 17 wt.%; Ni: 15 wt.%; Fe: 6 wt.%; Zn: 6 wt.%; Al: 3 wt.%; with the balance being Mn and other unavoidable impurities.

[0143] b. Alloy melting: A vacuum induction melting furnace is used. The alloy raw materials are placed in a crucible and melted in the vacuum induction melting furnace. During the melting process, an argon protective atmosphere is introduced. The induction heating is carried out to 1480℃ and held for no more than 60 minutes to ensure that the raw materials are fully melted, ensuring that the alloy composition is uniform and obtaining an alloy liquid that meets the composition requirements.

[0144] c. Casting process: This includes gating system installation, mold preheating, and alloy liquid pouring, as detailed below:

[0145] c-1. Gating System Installation: Assemble the gating system by combining the pouring cup 1, sprue 2, runner 3, ingate 4, and venting channel 5, thus completing the mold installation. Figure 3 As shown, it is installed on the mold; this embodiment adjusts some structures of the gating system, such as... Figure 3As shown, the venting channel 5 is also connected to the pouring cup 1 and the sprue 2, and more branch venting channels are provided to maintain the air pressure balance between the pouring cup 1, the sprue 2, and the venting channel 5. This gating system can effectively compensate for the shrinkage of the pipe during the solidification process, effectively improve the filling speed of the alloy liquid, and effectively improve the overall quality and service life of the pipe. At the same time, the layout of the venting channels is optimized and the number of venting channels is increased to ensure that the gas in the cavity can be discharged more smoothly. In this embodiment, a high-precision mold is manufactured, and the gating system channels and venting channels 5 are set, and a detachable core is installed to form the gating system.

[0146] c-2. Mold preheating: Place the assembled mold into a heating furnace and preheat it to 930℃ to reduce the temperature difference between the molten alloy and the mold and avoid cracking of the casting.

[0147] c-3. Alloy liquid pouring: Under vacuum conditions, the alloy liquid pouring temperature is controlled at 1535℃. The alloy liquid prepared in step b is poured into the pouring cup 1, so that the alloy liquid enters the tube cavity 6 through the pouring system. During the pouring process, the pouring speed is controlled at 4L / min to ensure that the alloy liquid fills the cavity smoothly.

[0148] d. Cooling, demolding and post-processing: After casting, the mold is naturally cooled in the furnace. After the alloy liquid has completely solidified, when the casting has cooled to no more than 200°C, the demolding operation is carried out. Then the thin-walled tube casting is post-processed, including cleaning and heat treatment, to obtain a tube with a wall thickness of 1.5mm.

[0149] e. Quality Inspection: Inspect the quality of pipe fittings to obtain qualified thin-walled high-temperature damping alloy pipe fitting products.

[0150] Experimental Test Analysis

[0151] Experimental testing and analysis were conducted on the thin-walled high-temperature damping alloy tubing. Samples of the tubing were cut and tested for microscopic observation. The high-temperature damping alloy material in this embodiment has an FCC single-phase structure. The internal friction is 0.01-0.043 within the temperature range of 400-800℃. Testing showed that all performance indicators of the thin-walled high-temperature damping alloy tubing met the design requirements, and the surface quality was good with no obvious defects.

[0152] Example 5

[0153] This embodiment is basically the same as the above embodiments, except that:

[0154] In this embodiment, alloy melting is performed using a vacuum induction melting furnace. The alloy raw materials are placed in a crucible and then melted inside the furnace under vacuum conditions. This induction heating ensures that the raw materials are fully melted, resulting in a uniform alloy composition and a molten alloy that meets the required composition. Vacuum melting offers better degassing and molten metal purification, but it is more expensive.

[0155] In this embodiment, the horizontal sprue 3 of the gating system has a trapezoidal cross-section, with the bottom width of the trapezoidal sprue 3 being greater than its top width. In this embodiment, the ratio of the top opening diameter to the bottom opening diameter of the pouring cup 1 is 1.27:1; the diameter of the sprue 2 is 83 mm.

[0156] In this embodiment, the horizontal gating 3 is located below the vertical gating 2. The horizontally arranged horizontal gating 3 is vertically connected to the vertical gating 2. Multiple ingates 4 are evenly distributed below the horizontal gating 3. The horizontal gating 3 guides the smooth flow and rapid distribution of the alloy liquid. The trapezoidal cross-section of the horizontal gating 3 has a bottom width greater than its top width, which can achieve uniform temperature of the molten metal, reduce the pressure head of the molten metal flowing into the vertical gating 2, and help reduce the impact of the flow from the vertical gating 2 on the wall of the horizontal gating 3, as well as reduce the disturbance of the molten metal. The end of the horizontal gating 3 is provided with a slag collection bag for collecting impurities and slag in the alloy liquid. Combined with the trapezoidal cross-section of the horizontal gating 3, it is conducive to the collection of impurities and slag in the molten metal, and ultimately achieves effective collection.

[0157] In the embodiments 1-5 of this invention, the alloy of this invention does not contain Mo, an element with a high melting point (2622℃). In existing damping alloys containing Mo, such as the two-phase high-temperature damping alloy material with patent publication number CN119121010A, the surface tension increases in the molten state, which to some extent affects the fluidity of the molten metal. Internal defects such as internal cracks may occur during the solidification of the damping alloy. In addition, since the mixing enthalpy between Cr and Mo and between Mo and Ni are both negative, it indicates that they also have strong interactions. This interaction can form solid solutions, intermetallic compounds, or increase solute elements. If Mo forms a solid solution or intermetallic compound with the matrix, it may affect the solidification point by changing the lattice constant, interatomic bonding force, and phase transition temperature, which may lead to an increase in the solidification point of the alloy liquid. The addition of the metallic element Cr raises the freezing point of the alloy liquid, narrowing the temperature window of the liquid metal during casting and solidification, reducing its fluidity, and even causing it to lose fluidity prematurely during solidification. This leads to defects such as shrinkage cavities or porosity in the casting, thus affecting its ability to fill the mold and the quality of the casting. Since the damping alloy of this invention is applied to thin-walled high-temperature damping alloy pipe fittings, the fluidity requirements during the alloy casting process are stringent. Under the condition of maintaining considerable damping performance and meeting the requirement that the internal loss of the damping alloy is not less than 0.01 in the temperature range of 400-800℃, the damping alloys of Examples 1-5 of this invention can be well applied to the preparation of thin-walled pipe fittings with a wall thickness ≤2mm. Compared to the dual-phase high-temperature damping alloy material with patent publication number CN119121010A, although the internal damping loss of the alloy is slightly insufficient, the damping alloys of the above embodiments 1-5 of this invention applied to thin-walled high-temperature damping alloy pipe fittings can achieve higher damping performance through large-scale use, combination of thin-walled high-temperature damping alloy pipe fittings of different specifications, forming multi-segment pipe connection structures and forming distributed damping alloy pipe segments. This can effectively control costs and meet the application requirements of thin-walled high-temperature damping alloy pipe fittings, which is difficult to achieve with the dual-phase high-temperature damping alloy material with patent publication number CN119121010A. Furthermore, since the metallic material of this invention does not contain elements such as Mo, W, Zr, and Ti with low vapor pressure (not easily volatile), and the target alloy is not for smelting high-strength or ultra-high-strength steel, it does not require expensive equipment and demanding process conditions such as vacuum smelting. This invention preferably uses an inert gas protective atmosphere for melting, which simplifies equipment requirements. The purification and impurity removal effects of the molten metal also meet the basic requirements of high-quality damping alloys, satisfying the critical needs of most industries for thin-walled damping alloys. Vacuum melting can significantly remove gas inclusions and strictly control the reactive elements in the alloy, significantly improving the quality of the thin-walled damping alloy. This makes it suitable for applications requiring extremely high material purity and performance, such as thin-walled tubing in precision systems, aerospace damping functional tubing, and ultra-thin damping alloy tubing.

[0158] Furthermore, the damping alloy matrix of this invention, with its fcc single-phase structure, offers advantages over fcc and bcc bidirectional damping alloys in the fabrication of thin-walled high-temperature damping alloy pipes. The fcc single-phase damping alloy microstructure of this invention outperforms fcc and bcc bidirectional damping alloys in terms of plasticity, low-temperature performance, and weldability. While fcc and bcc bidirectional damping alloys exhibit superior strength due to their excessively high hardness, their processing performance is relatively low, particularly in the fabrication of thin-walled pipes, especially bends or other irregularly shaped components, making them difficult to manufacture. The fcc single-phase damping alloy microstructure of this invention possesses abundant slip systems, allowing more dislocations to pass through the slip system alloy crystals, thus imparting better ductility. Its stacking fault performance is low, and dislocations easily expand to form more slip bands, further enhancing plasticity. In contrast, bidirectional damping alloys containing bcc have high hardness; for example, bidirectional damping alloys containing Cr hardness-strengthening phases are more difficult to process and form, especially at room temperature, where slip resistance is high, dislocation movement is hindered, and plasticity is relatively poor. Furthermore, the FCC single-phase damping alloy of this invention not only possesses excellent high-temperature damping performance in the 400-800℃ temperature range, but also exhibits good room-temperature and low-temperature damping performance. This broad-spectrum damping performance is difficult to achieve with FCC and BCC bidirectional damping alloys. Additionally, the presence of BCC microstructure in FCC and BCC bidirectional damping alloys results in higher overall alloy hardness and reduced plasticity due to the higher hardness and Young's modulus of the BCC microstructure. Moreover, the biphase microstructure may exhibit complex behaviors such as periodic twinning and nanostructure subcrystalline arrangement during material processing or service deformation. While these behaviors can increase the local strength of the damping alloy, they may reduce its overall plasticity. Although the yield strength and elastic modulus of the FCC single-phase damping alloy of this invention increase slowly under low-temperature conditions, and the toughness decreases slightly, the plasticity remains relatively stable or slightly reduced, which does not affect its service life. Because the alloy itself possesses sufficient strength and toughness and a stable microstructure, it is not prone to brittle fracture or static damage during the service of thin-walled pipes, resulting in a long service life in vibration damping and noise reduction applications. Furthermore, the FCC single-phase damping alloy of this invention also has good welding and processing properties, making it easy to control material deformation and reduce cracking tendency during welding and processing, making it suitable for forming complex thin-walled pipes or high-precision machining of thin-walled pipes.

[0159] In summary, in embodiments 1-5 of this invention, the thin-walled high-temperature damping alloy tubing, its preparation method, and gating system optimize the alloy composition and increase the filling capacity of the alloy liquid. In particular, this invention effectively combines composition design with the preparation process and equipment. By using Cr-free and Mo-free high-temperature damping alloy materials to prepare the thin-walled high-temperature damping alloy tubing, this invention ensures a balance between the fluidity of the molten metal and the overall performance of the damping alloy, ensuring that all performance indicators of the thin-walled high-temperature damping alloy tubing meet design requirements, with good surface quality and no obvious defects. This invention effectively solves the problems of insufficient casting, cold shuts, cracking, and unstable high-temperature damping performance existing in the manufacturing process of thin-walled high-temperature damping alloy tubing in the prior art, meeting the demand for developing high-quality alloy castings with compatible composition and processes. This invention enables the widespread application of thin-walled high-temperature damping alloy tubing in aerospace, automotive, shipbuilding, and high-precision instrument manufacturing fields.

[0160] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made according to the purpose of the invention. Any changes, modifications, substitutions, combinations or simplifications made based on the spirit and principle of the technical solution of the present invention shall be equivalent substitutions. As long as they meet the purpose of the invention and do not deviate from the technical principle and inventive concept of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A thin-walled high-temperature damping alloy pipe fitting, characterized in that, The chemical element mass percentages of the components of the high-temperature damping alloy are as follows: Cu: 13-17 wt.%; Ni: 8-15 wt.%; Fe: 2-6 wt.%; Zn: 3-9 wt.%; Al: 0.5-3 wt.%; with the balance being Mn and other unavoidable impurities. The raw materials are weighed according to the proportions of the components of the high-temperature damping alloy. The raw materials are melted under vacuum or inert gas atmosphere and then held at 1400-1600℃ to ensure complete melting and the formation of an alloy liquid. The alloy liquid is then cast to obtain a thin-walled high-temperature damping alloy pipe fitting.

2. The thin-walled high-temperature damping alloy pipe fitting according to claim 1, characterized in that: The pipe fitting is a thin-walled pipe fitting with a wall thickness of ≤2mm, and the pipe fitting is at least one of straight pipe, bend pipe, reducer pipe and other special-shaped pipe fittings.

3. The thin-walled high-temperature damping alloy pipe fitting according to claim 1, characterized in that: The high-temperature damping alloy matrix of the pipe fitting has an fcc single-phase structure.

4. The thin-walled high-temperature damping alloy pipe fitting according to claim 1, characterized in that: In the preparation of high-temperature damping alloy, the raw materials are placed in a crucible according to the mass percentage and then placed in a vacuum induction melting furnace for melting. During the melting process, an argon protective atmosphere is introduced, and the temperature is held at 1400-1600℃ to allow the raw materials to fully melt and form an alloy liquid. The alloy liquid is then cast to obtain the pipe fitting.

5. A method for preparing a thin-walled high-temperature damping alloy tubular fitting according to any one of claims 1-4, characterized in that, Includes the following steps: a. Mold preparation: Manufacture the mold, set up the gating system channels and venting channels, install the detachable core, and form the gating system; b. Alloy melting: Using a vacuum induction melting furnace, the raw materials are weighed according to the chemical element mass percentage of the components of the target high-temperature damping alloy. The alloy is melted in a vacuum environment or an inert gas protective atmosphere, with the alloy melting temperature set at 1400-1600℃ and the melting time controlled to obtain the alloy liquid. c. Casting process: Using the casting system, the mold is preheated, and the molten alloy is poured into the pouring cup in a vacuum environment or an inert gas protective atmosphere. The molten alloy enters the shell cavity through the casting system. The casting flow rate and speed are controlled, and the casting temperature is monitored to ensure that the molten alloy can fill the cavity smoothly. d. Cooling, demolding and post-processing: After casting, allow the mold to cool and demold after the alloy liquid has completely solidified; then perform post-processing on the demolded thin-walled tube casting to obtain the tube fitting. e. Quality Inspection: Inspect the quality of pipe fittings to obtain qualified thin-walled high-temperature damping alloy pipe fitting products.

6. The method for preparing the thin-walled high-temperature damping alloy pipe fitting according to claim 5, characterized in that: In step c, the mold preheating temperature is 900-1000℃.

7. A casting system for preparing the thin-walled high-temperature damping alloy tubular component according to any one of claims 1-4, comprising silica sol and zirconium dioxide, wherein the casting system is used to prepare the thin-walled high-temperature damping alloy tubular component under vacuum or inert gas protective atmosphere, characterized in that, The gating system includes a pouring cup (1), a sprue (2), a runner (3), an ingate (4), and a venting channel (5); The pouring cup (1) is funnel-shaped and is used to receive the molten alloy from the ladle; the inner wall of the pouring cup (1) is provided with a smooth surface coated with graphene. The sprue (2) is a vertical channel with a circular cross-section. The sprue (2) is connected to the bottom of the pouring cup (1) and guides the alloy liquid in the pouring cup (1) vertically to the horizontal sprue (3). The sprue (2) is equipped with spiral guide vanes. The horizontal gating system (3) adopts a trapezoidal or rectangular cross-section. The bottom width of the horizontal gating system (3) with a trapezoidal cross-section is greater than the top width, and the bottom width of the horizontal gating system (3) with a rectangular cross-section is the same as the top width. The horizontal gating system (3) is located below the sprue (2). The horizontal gating system (3) is horizontally connected to the sprue (2) vertically. Multiple ingates (4) are evenly distributed below the horizontal gating system (3). The horizontal gating system (3) guides the smooth flow and rapid distribution of the alloy liquid. A slag collection bag is provided at the end of the horizontal gating system (3) to collect impurities and slag in the alloy liquid. The ingate (4) is flat and each ingate (4) is connected to the pipe cavity (6). The alloy liquid in the horizontal runner (3) enters the pipe cavity (6) through the ingate (4). The width of the ingate (4) is adjusted according to the pipe wall thickness, and the number and position of the ingate (4) are arranged according to the pipe structure. Multiple exhaust channels (5) are provided on the top and side of the tube cavity (6) so that the exhaust channels (5) are connected to the atmosphere; a filter device is provided at the inlet of the exhaust channel (5).

8. The gating system according to claim 7, characterized in that: The cross-sectional shape of the exhaust duct (5) is circular or rectangular. The diameter or width of the exhaust duct (5) is set according to the volume of the pipe cavity (6) and the gas discharge rate.

9. The gating system according to claim 7, characterized in that: The ratio of the diameter of the top opening of the pouring cup (1) to the diameter of its bottom opening is 1.27:1; Alternatively, the diameter of the sprue (2) is no greater than 83 mm.

10. The gating system according to claim 7, characterized in that: The exhaust channel (5) is also connected to the pouring cup (1) or the sprue (2), providing more branch exhaust channels so that the gas in the tube cavity (6) can be discharged more smoothly.

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