Manufacturing method of gradient vibration reduction composite pipe

Abstract

The invention discloses a manufacturing method of a gradient vibration reduction composite pipe. The problem that an existing composite pipe is poor in vibration reduction and sound absorption effect is solved. The manufacturing method comprises the following steps: packaging a foaming material in each embedded pipe to obtain a plurality of embedded pipes with different foaming agent mass fractions; the embedded pipe row is arranged in an annular gap formed by sleeving the outer pipe and the inner pipe, the embedded pipe row is distributed in the mode that the mass fraction of the foaming agent is reduced layer by layer from the inner wall of the outer pipe to the outer wall of the inner pipe in the radial direction, and a first composite pipe blank is obtained; the plurality of embedded pipes have at least two different pipe diameters, and the pipe diameters of the embedded pipes are reduced layer by layer in the direction from the outer pipe to the inner pipe; or the embedded pipes with smaller pipe diameters are distributed close to the outer wall of the inner pipe and the inner wall of the outer pipe, and the embedded pipes with larger pipe diameters are distributed between the two layers of embedded pipes with smaller pipe diameters in the circumferential direction; sealing the open end of the annular gap by using a packaging plate; and the third composite pipe blank is heated through internal spinning, so that the foaming material is foamed, and the gradient vibration reduction composite pipe with the foam metal layer is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of metal tube processing, and in particular to a method for manufacturing a gradient vibration-damping composite tube. Background Art

[0002] Foam metal sandwich structures and foam metals have the characteristics of light weight, high specific stiffness, sound absorption, vibration reduction, heat preservation, and thermal insulation. However, the existing preparation process of foam metal composite pipes usually adopts an inner metal pipe, an outer metal pipe and a foaming powder located in the middle to be extruded into an integral body and then heated, so that the middle layer foams to form a foam metal layer to obtain a foam metal sandwich composite pipe. However, the structure of the foam metal layer is simple and the mechanical properties in the composite pipe are weak, resulting in poor vibration reduction and sound absorption effects of the obtained composite pipe. Summary of the Invention

[0003] The object of the present invention is to provide a method for manufacturing a gradient vibration-damping composite pipe, so as to improve the vibration-damping and sound-absorbing effects and mechanical properties of the composite pipe.

[0004] In order to achieve the above objectives, the present invention provides the following technical solutions: In a first aspect, the present invention provides a method for manufacturing a gradient vibration damping composite tube, comprising: Providing a metal outer tube, a metal inner tube and a plurality of embedded tubes; Encapsulating each embedded tube with a foaming material, the foaming material comprising a foaming agent and metal powder, to obtain a plurality of embedded tubes with different foaming agent mass fractions; A plurality of embedded tubes are closely arranged within an annular gap formed by the sheathing of a metal outer tube and a metal inner tube, such that the plurality of embedded tubes are distributed within the annular gap in a manner such that the mass fraction of the foaming agent decreases radially from the inner wall of the metal outer tube to the outer wall of the metal inner tube, thereby obtaining a first composite tube blank; wherein the plurality of embedded tubes have at least two different diameters, and the diameters of the plurality of embedded tubes decrease layer by layer in a direction from the inner wall of the metal outer tube to the outer wall of the metal inner tube; alternatively, the embedded tubes with smaller diameters are distributed near the outer wall of the metal inner tube and near the inner wall of the metal outer tube, and the embedded tubes with larger diameters are distributed circumferentially between two layers of embedded tubes with smaller diameters; The open end of the annular gap is sealed with a packaging plate to obtain a second composite tube blank; Performing internal spinning on the second composite tube blank to a target wall thickness to obtain a third composite tube blank; The third composite tube blank is heated to foam the foaming material, thereby obtaining a gradient vibration-damping composite tube having a foam metal layer.

[0005] Optionally, in the manufacturing method of the above-mentioned gradient vibration-damping composite tube, after the multiple embedded tubes are tightly arranged in the annular gap formed by the metal outer tube and the metal inner tube, and before the open end of the annular gap is sealed with a packaging plate, the manufacturing method also includes: filling metal chips into the outer wall gaps of the multiple embedded tubes.

[0006] Optionally, in the above-mentioned method for manufacturing the gradient vibration-damping composite tube, the wall thickness of the embedded tube is 2 mm to 4 mm, and the inner diameter of the embedded tube is 10 mm to 30 mm.

[0007] Optionally, in the above-mentioned method for manufacturing the gradient vibration-damping composite tube, the temperature for heating the third composite tube blank is 650° C. to 1350° C., and the foaming time of the foaming material is 5 min to 10 min.

[0008] Optionally, in the above-mentioned method for manufacturing the gradient vibration-damping composite tube, the packaging plate comprises metal and / or resin; The metal outer tube and the metal inner tube are both alloy steel tubes or aluminum alloy tubes; The embedded pipe is one or more of an iron pipe, an aluminum pipe, and a stainless steel pipe.

[0009] Optionally, in the manufacturing method of the gradient vibration damping composite tube, the foaming agent in the foaming material is TiH2 with a mass fraction of 1% to 2%, and the metal powder is aluminum powder; Alternatively, the foaming agent in the foaming material is SrCO3 with a mass fraction of 2% to 3%, and the metal powder is iron powder.

[0010] Compared with the traditional method of obtaining a composite tube by using a foam metal interlayer with a unified structure, the present application fills different embedded tubes with different mass fractions of foaming agents, seals and welds them, and then tightly arranges multiple embedded tubes in an annular gap formed by the metal outer tube and the metal inner tube. The foaming agent is distributed in a radial direction from the inner wall of the metal outer tube to the outer wall of the metal inner tube in a layer-by-layer manner, so that the foaming material is encapsulated and constrained by multiple embedded tubes, and the foaming material is constrained in various positions in the annular gap, thereby improving the uniformity of the distribution of the foaming material and improving the stability of the gradient distribution of different foaming structures in the composite tube after foaming; then it is spun to the target wall thickness, and finally heated and foamed, so that the formed foam metal layer is used as the core layer of the composite tube. Due to the different mass fractions of the foaming agent, the porosity formed after foaming is different, and the porosity of the obtained foam metal layer can be between the metal outer tube and the metal inner tube. The plurality of embedded tubes are distributed in a gradient decreasing manner, and the diameters of the plurality of embedded tubes are different. When the diameters of the plurality of embedded tubes decrease layer by layer in the direction from the inner wall of the metal outer tube to the outer wall of the metal inner tube, the larger the diameter, the larger the gap between adjacent embedded tubes. After internal spinning and foaming, the gaps formed at the embedded tubes with larger diameters are larger and the porosity is higher. On the contrary, the smaller the diameter, the smaller the gaps between adjacent embedded tubes. After internal spinning and foaming, the gaps formed at the embedded tubes with smaller diameters are smaller and the porosity is lower. The embedded tubes with smaller diameters can provide good structural support and barrier capabilities as supporting skeletons, so that the gradient vibration damping composite tube respectively assumes the functions of "initial absorption-deep dissipation-structural support" at different radial positions, forming a gradient interception of sound wave / vibration energy, avoiding the problem of weak mechanical properties of single porosity materials in the composite tube, so as to ensure the balance between strength and vibration damping and sound absorption performance of the gradient vibration damping composite tube.When the inner embedded pipes with smaller diameters are distributed close to the outer wall of the metal inner pipe and close to the inner wall of the metal outer pipe, and the inner embedded pipes with larger diameters are distributed in the circumferential direction between the two layers of the inner embedded pipes with smaller diameters, the gradient damping composite pipe constructs different functional layers at different radial positions. The outer layer and the inner layer close to the foam metal layer have smaller gaps between the adjacent inner embedded pipes due to the smaller diameters of the inner embedded pipes, and multiple inner embedded pipes with smaller diameters can provide good structural support and blocking capacity as a support framework. The middle layer close to the foam metal layer has larger gaps between the adjacent inner embedded pipes due to the larger diameters of the inner embedded pipes, and the inner embedded pipes with larger diameters can provide structural support while having good flexible deformation, which can provide expansion space for the foaming material inside the inner embedded pipes with larger diameters, so that the foam metal layer forms a "hard-soft-hard" radial gradient distribution, and the mass fraction of the foaming agent filled from the outside to the inside is gradually reduced layer by layer, so that the porosity of the foam metal layer decreases in steps from the inner wall of the metal outer pipe to the outer wall of the metal inner pipe, forming a gradient interception of sound waves / vibration energy. Compared with the foam metal layer formed by the inner embedded pipes with the same diameter and the foaming agent material with the same mass fraction, the problem of weak mechanical properties of a single porosity material in the composite pipe is avoided, and the balance between the strength and the damping and sound absorption performance of the gradient damping composite pipe is ensured.

[0011] In a second aspect, the present application further provides a manufacturing method of the gradient damping composite pipe, comprising: providing a metal outer pipe, a metal inner pipe, a base and a plurality of metal solid rods, wherein one end of the metal outer pipe and the metal inner pipe is fixed by the base, and an annular filling cavity is formed between the metal outer pipe, the metal inner pipe and the base; arranging the plurality of metal solid rods in the annular filling cavity; wherein the plurality of metal solid rods have at least two different diameters, and the diameters of the plurality of metal solid rods decrease layer by layer in the direction from the inner wall of the metal outer pipe to the outer wall of the metal inner pipe; or the metal solid rods with smaller diameters are distributed close to the outer wall of the metal inner pipe and close to the inner wall of the metal outer pipe, and the metal solid rods with larger diameters are distributed in the circumferential direction between the two layers of the metal solid rods with smaller diameters; filling the foaming material with different mass fractions of foaming agent into the gaps between the adjacent metal solid rods, so that the mass fraction of the foaming agent of the foaming material in the annular filling cavity decreases layer by layer in the radial direction from the inner wall of the metal outer pipe to the outer wall of the metal inner pipe; sealing the open end of the annular filling cavity by using a sealing plate to obtain a fourth composite pipe blank; performing internal spinning processing on the fourth composite pipe blank to the target wall thickness to obtain a fifth composite pipe blank; heating the fifth composite pipe blank to make the foaming material foam to form the gradient damping composite pipe with the foam metal layer.

[0012] Optionally, in the above-mentioned method for manufacturing the gradient vibration-damping composite tube, the diameter of the metal solid rod is 10 mm to 30 mm.

[0013] Optionally, in the above-mentioned method for manufacturing the gradient vibration-damping composite tube, the temperature for heating the fifth composite tube blank is 650° C. to 1350° C., and the foaming time of the foaming material is 5 min to 10 min.

[0014] Optionally, in the above-mentioned method for manufacturing the gradient vibration-damping composite tube, the metal solid rod is an iron rod or an aluminum rod; The packaging plate includes metal and / or resin; The metal outer tube and the metal inner tube are both alloy steel tubes or aluminum alloy tubes.

[0015] Optionally, in the manufacturing method of the gradient vibration damping composite tube, the foaming agent in the foaming material is TiH2 with a mass fraction of 1% to 2%, and the metal powder is aluminum powder; Alternatively, the foaming agent in the foaming material is SrCO3 with a mass fraction of 2% to 3%, and the metal powder is iron powder.

[0016] Compared with the traditional method of obtaining a composite tube by using a foam metal interlayer with a unified structure, the present application arranges multiple metal solid rods tightly in an annular filling cavity, so that a gap for filling the foaming material is formed in the annular filling cavity with a stable radial distribution. By distributing foaming agents of different mass fractions in the gaps between multiple metal solid rods and sealing them, the position of the foaming material in the annular gap is constrained by multiple metal solid rods, so that the foaming material is evenly distributed in the annular gap, and after foaming, the stability of the gradient distribution of different foaming structures in the composite tube is improved; then it is spun to the target wall thickness, and finally heated and foamed, so that the formed foam metal layer serves as the core layer of the composite tube. Due to the different mass fractions of the foaming agent, the porosity formed after foaming is different, and the multiple metal solid rods use different diameters, and the metal solid rods of different diameters are distributed differently in the annular filling cavity along the radial direction. Therefore, the porosity of the obtained foam metal layer can be gradiently distributed between the metal inner tube and the metal outer tube. When the diameters of the metal solid rods decrease layer by layer from the inner wall of the metal outer tube to the outer wall of the metal inner tube, the larger the diameter, the larger the gap between adjacent metal solid rods. After internal spinning and foaming, the gaps formed at the metal solid rods with larger diameters are larger and the porosity is higher. Conversely, the smaller the diameter, the smaller the gaps between adjacent metal solid rods. After internal spinning and foaming, the gaps formed at the metal solid rods with smaller diameters are smaller and the porosity is lower. In combination with the gradual decrease in the mass fraction of the foaming agent filled from the outside to the inside, the porosity of the foam metal layer decreases in a step-by-step manner from the inner wall of the metal outer tube to the outer wall of the metal inner tube in the radial direction (i.e., the porosity in the outer layer is higher and the porosity in the inner layer is lower). The gradient vibration damping composite tube forms a gradient interception of sound wave / vibration energy at different radial positions, resulting in a larger comprehensive porosity within the annular filling cavity. This avoids the problem of weak mechanical properties of single-porosity materials in the gradient vibration damping composite tube, thereby ensuring a balance between strength and vibration damping and sound absorption performance of the gradient vibration damping composite tube.When the metal solid rods with smaller diameters are distributed close to the outer wall of the metal inner tube and close to the inner wall of the metal outer tube, and the metal solid rods with larger diameters are distributed circumferentially between the two layers of metal solid rods with smaller diameters, the outer and inner layers close to the foam metal layer have smaller diameters of the metal solid rods, resulting in smaller gaps between adjacent metal solid rods and less foaming material filled. Multiple metal solid rods with smaller diameters can serve as a supporting skeleton to provide good structural support and barrier capabilities. The middle layer close to the foam metal layer has larger diameters of the metal solid rods, resulting in larger gaps between adjacent metal solid rods, and the metal solid rods with larger diameters can provide structural support. At the same time, the larger gap foam can be filled with more foaming material, which provides sufficient expansion space for the foaming material. The pores of the porous structure can disperse and absorb part of the vibration energy. The mass fraction of the foaming agent filled from the outside to the inside decreases layer by layer, so that the porosity of the foam metal layer decreases in a step-by-step manner from the inner wall of the metal outer tube to the outer wall of the metal inner tube along the radial direction, forming a gradient interception of sound waves / vibration energy. Compared with the foam metal layer formed by a solid metal rod of the same diameter and the same mass fraction of foaming agent material, the problem of weak mechanical properties of a single porosity material in the composite pipe is avoided, and the balance between the strength and vibration reduction and sound absorption performance of the gradient vibration damping composite pipe is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 This is a process flow chart of a method for manufacturing a gradient vibration-damping composite tube provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of a second distribution method of embedded tubes or metal solid rods in a method for manufacturing a gradient vibration-damping composite tube provided in an embodiment of the present invention; Figure 3 Schematic diagram of a third distribution mode of embedded tubes or metal solid rods in a method for manufacturing a gradient vibration-damping composite tube provided in an embodiment of the present invention; Figure 4 This is a process flow chart of another method for manufacturing a gradient vibration-damping composite tube provided in an embodiment of the present invention.

[0018] Reference numerals: 1-Metal outer tube; 2-Metal inner tube; 3-Embedded tube. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0022] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0023] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and may encompass internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0024] like Figures 1-3 As shown, an embodiment of the present invention provides a method for manufacturing a gradient vibration damping composite pipe, comprising: In step S100 , a metal outer tube 1 , a metal inner tube 2 and a plurality of embedded tubes 3 are provided.

[0025] In step S200, a foaming material is encapsulated within each embedded tube 3. The foaming material comprises a foaming agent and metal powder, resulting in multiple embedded tubes 3 having varying mass fractions of the foaming agent. The foaming agent and metal powder are thoroughly mixed and then loaded into the embedded tubes 3. The two ends of the embedded tubes 3 are then sealed by welding with metal blocks. Alternatively, bonding or other sealing methods may be employed, as long as the metal blocks are tightly connected to the ends of the embedded tubes 3 and prevent leakage of the foaming material. For example, the metal blocks may be made of iron, aluminum, or other metal materials.

[0026] In step S300, a plurality of embedded tubes 3 are tightly arranged within the annular gap formed by the sleeved metal outer tube 1 and the metal inner tube 2, such that the plurality of embedded tubes 3 are distributed within the annular gap in a manner that decreases radially from the inner wall of the metal outer tube 1 to the outer wall of the metal inner tube 2 according to the mass fraction of the foaming agent, thereby obtaining a first composite tube blank. The plurality of embedded tubes may have at least two different diameters, and the diameters of the plurality of embedded tubes decrease layer by layer from the inner wall of the metal outer tube to the outer wall of the metal inner tube; alternatively, the smaller diameter embedded tubes are arranged near the outer wall of the metal inner tube and near the inner wall of the metal outer tube, while the larger diameter embedded tubes are circumferentially distributed between the two layers of smaller diameter embedded tubes. Specifically, the metal outer tube 1 and the metal inner tube 2 are coaxially positioned, and the metal outer tube 1 and the metal inner tube 2 may be fixed together by riveting or other fixing methods, as long as the annular gap formed by the sleeved metal outer tube 1 and the metal inner tube 2 is secured.

[0027] In step S400, the open end of the annular gap is sealed with a sealing plate to obtain a second composite tube blank. The sealing plate and the open end of the annular gap can be connected by welding, bonding, or other fixed connection methods, as long as the sealing plate and the open end of the annular gap are tightly connected and no internal material leaks.

[0028] Step S500 , performing internal spinning on the second composite tube blank to a target wall thickness to obtain a third composite tube blank.

[0029] Step S600: Heating the third composite tube blank to foam the foaming material, thereby obtaining a gradient vibration damping composite tube having a foam metal layer. Specifically, while heating the third composite tube blank to foam the foaming material, the third composite tube blank can be placed in a mold. For example, the mold can employ a cavity structure formed by a sleeved outer wall metal tube and an inner wall metal tube. The outer wall diameter of the third composite tube blank is the same as the inner diameter of the outer wall metal tube, and the inner wall diameter of the third composite tube blank is the same as the outer diameter of the inner wall metal tube. The cavity structure formed by the sleeved outer wall metal tube and the inner wall metal tube constrains the surface of the third composite tube blank to prevent expansion and deformation of the third composite tube blank during the heating and foaming process.

[0030] Compared with the traditional method of obtaining a composite tube by using a single-structure foam metal interlayer, the present application fills different embedded tubes 3 with different mass fractions of foaming agents, seals and welds them, and then tightly arranges multiple embedded tubes 3 in the annular gap formed by the metal outer tube 1 and the metal inner tube 2. The mass fraction of the foaming agent is distributed in a radial direction from the inner wall of the metal outer tube 1 to the outer wall of the metal inner tube 2 in a layer-by-layer manner. The foaming material is encapsulated and constrained by the multiple embedded tubes 3, and the foaming material is constrained at various positions in the annular gap, thereby improving the uniformity of the distribution of the foaming material and improving the stability of the gradient distribution of different foaming structures in the composite tube after foaming. Then it is spun to the target wall thickness, and finally heated and foamed, so that the formed foam metal layer is used as the core layer of the composite tube. Due to the different mass fractions of the foaming agent, the porosity formed after foaming is different, and the multiple embedded tubes 3 adopt different tube diameters, and the embedded tubes 3 with different tube diameters are distributed differently in the radial direction within the annular gap. Therefore, the porosity of the obtained foam metal layer can be distributed in a gradient between the metal inner tube 2 and the metal outer tube 1. Among them, when the multiple embedded tubes 3 have at least two different tube diameters, in the direction from the inner wall of the metal outer tube 1 to the outer wall of the metal inner tube 2, the tube diameters of the multiple embedded tubes 3 decrease layer by layer, and the larger the tube diameter, the smaller the gap between adjacent embedded tubes 3. The larger the diameter, the larger the gap formed at the embedded tube 3 with a larger diameter and the higher the porosity. On the contrary, the smaller the diameter, the smaller the gap between the adjacent embedded tubes 3. After the inner spinning and foaming, the smaller the gap formed at the embedded tube 3 with a smaller diameter and the lower the porosity. The mass fraction of the foaming agent filled from the outside to the inside decreases layer by layer, so that the porosity of the foam metal layer decreases in a step-by-step manner from the inner wall of the metal outer tube 1 to the outer wall of the metal inner tube 2 in the radial direction (that is, the porosity in the outer layer is higher and the porosity in the inner layer is lower), so that the gradient vibration damping composite tube assumes the functions of "initial absorption-deep dissipation-structural support" at different radial positions, forming a gradient vibration damping composite tube. The gradient interception of paired sound waves / vibration energy and the large comprehensive porosity in the annular gap avoid the performance limitations of a single porosity structure compared to the embedded tube 3 of the same diameter and the foam metal layer formed by the same mass fraction of the foaming agent material. When the gradient vibration damping composite tube is subjected to external force vibration, the higher porosity structure located in the outer layer provides an elastic buffering effect. Through the compression and flow of the medium (air or filling material) in the pores of the porous structure and the flexible deformation of the tube wall structure layer of the embedded tube 3 as the porous structure skeleton, part of the vibration energy is first dispersed and absorbed, reducing the vibration amplitude transmitted to the inside of the tube wall, thereby improving the sound absorption and vibration reduction performance of the gradient vibration damping composite tube.

[0031] When the plurality of embedded tubes 3 have at least two different diameters, the embedded tubes 3 with smaller diameters are distributed close to the outer wall of the metal inner tube 2 and close to the inner wall of the metal outer tube 1, and the embedded tubes 3 with larger diameters are distributed between the two layers of embedded tubes 3 with smaller diameters along the circumferential direction, the gradient vibration damping composite tube constructs different functional layers at different radial positions. The outer layer and the inner layer close to the foam metal layer have smaller diameters of the embedded tubes 3, so that the gaps between adjacent embedded tubes 3 are smaller. The plurality of embedded tubes 3 with smaller diameters can provide good structural support and barrier capabilities as supporting skeletons. The middle layer close to the foam metal layer has larger diameters of the embedded tubes 3, so that the gaps between adjacent embedded tubes 3 are larger. The embedded tubes with larger diameters Tube 3 can provide structural support while having good flexible deformation, and can provide expansion space for the foaming material inside the embedded tube 3 with a larger diameter, so that the foam metal layer forms a radial gradient distribution of "hard-soft-hard". The mass fraction of the foaming agent filled from the outside to the inside decreases layer by layer, so that the porosity of the foam metal layer decreases in a step-by-step manner from the inner wall of the metal outer tube 1 to the outer wall of the metal inner tube 2 along the radial direction, forming a gradient interception of sound wave / vibration energy. Compared with the foam metal layer formed by the embedded tube 3 of the same diameter and the foam metal layer with the same mass fraction of the foaming agent material, it avoids the problem of weak mechanical properties of a single porosity material in the composite tube, and ensures the balance between the strength and vibration reduction and sound absorption performance of the gradient vibration damping composite tube.

[0032] For example, Figure 2 As shown, three layers of embedded tubes 3 are radially arranged in the annular gap. From the outside to the inside, they are the first layer of embedded tubes 3, the second layer of embedded tubes 3, and the third layer of embedded tubes 3. The diameters of the three layers of embedded tubes 3 decrease from the outside to the inside. Each layer of embedded tubes 3 is closely arranged along the circumference. The foaming material in the same layer of embedded tubes 3 has the same foaming agent mass fraction, and the foaming agent mass fraction of the foaming material in the three layers of embedded tubes 3 decreases from the outside to the inside. Of course, two, four, or other layers of embedded tubes 3 with different diameters can also be arranged radially in the annular gap. like Figure 3 As shown, for example, four layers of embedded tubes 3 are radially arranged in the annular gap, namely, from the outside to the inside, the first layer of embedded tubes 3, the second layer of embedded tubes 3, the third layer of embedded tubes 3, and the fourth layer of embedded tubes 3. The diameter of the first layer of embedded tubes 3 is the same as the diameter of the fourth layer of embedded tubes 3, the diameter of the second layer of embedded tubes 3 is the same as the diameter of the third layer of embedded tubes 3, and the diameter of the first layer of embedded tubes 3 is smaller than the diameter of the second layer of embedded tubes 3. Each layer of embedded tubes 3 is closely arranged along the circumference, and the foaming material in the same layer of embedded tubes 3 has the same foaming agent mass fraction. The foaming agent mass fraction of the foaming material in the four layers of embedded tubes 3 decreases from the outside to the inside. Of course, two, three, five, or other layers of embedded tubes 3 with different diameters can also be arranged radially in the annular gap.

[0033] It should be noted that due to Figure 2The arrangement shown is compared to Figure 3 The arrangement shown has a higher overall porosity, so Figure 2 The sound absorption effect of the arrangement shown is better than Figure 3 The sound absorption effect of the arrangement shown; in terms of the strength of the composite tube, Figure 3 The composite tube strength of the arrangement shown is better than Figure 2 The strength of the composite pipes arranged in the manner shown is such that operators can select gradient vibration-damping composite pipes of different structures according to actual work requirements.

[0034] In some embodiments, after closely arranging the plurality of embedded tubes 3 within the annular gap formed by the sleeved metal outer tube 1 and the metal inner tube 2 in step S300, and before sealing the open ends of the annular gap with a packaging plate in step S400, the manufacturing method further includes step S301: filling the outer wall gaps of the plurality of embedded tubes 3 with metal chips. The metal chips can be iron chips, aluminum chips, or other metal chips, as long as they can form a good metallurgical bond with the metal outer tube 1, the metal inner tube 2, and the embedded tubes 3. By filling with metal chips, relative movement of the plurality of embedded tubes 3 within the annular gap can be limited during the internal spinning process, ensuring a stable and uniform arrangement.

[0035] In some embodiments, after sealing the open ends of the annular gaps with the encapsulating plate in step S400 and before performing the internal spinning process on the second composite tube blank in step S500, the manufacturing method further includes: evacuating the plurality of sealed and welded embedded tubes. This prevents the foaming material within the embedded tubes from being heated at high temperatures and coming into contact with oxygen during the foaming process, thereby preventing oxidation.

[0036] Specifically, in this embodiment, the wall thickness of the embedded tube 3 is 2mm~4mm, and the inner diameter of the embedded tube 3 is 10mm~30mm. For example, the wall thickness of the embedded tube 3 can be 2mm, 3mm, 3.5mm, 4mm, etc., and the inner diameter of the embedded tube 3 can be 10mm, 15mm, 20mm, 30mm, etc. The operator can select embedded tubes 3 of different sizes according to actual work needs and in combination with the arrangement of different structures. Among them, the wall thickness of the embedded tube 3 is greater than 2mm, so that the wall thickness of the embedded tube 3 can withstand a certain extrusion strength, avoiding the risk of cracking of the embedded tube 3 during the internal spinning in step S500, resulting in leakage of the inner layer foam material of the embedded tube 3. The wall thickness of the embedded tube 3 is less than 4 mm, so that the expansion constraint force of the embedded tube 3 on the foaming material during the foaming process is not too large, and the embedded tube 3 has good flexibility, and can undergo micro-deformation synchronously with the expansion of the foaming material inside the embedded tube 3 during the foaming process. Considering that too large or too small wall thickness of the embedded tube 3 will have adverse effects, the wall thickness of the embedded tube 3 is selected to be 2 mm to 4 mm to ensure that the embedded tube 3 can withstand a certain extrusion strength while reducing stress concentration in the interface area when temperature changes or external forces act, so as to ensure the uniformity of foaming of the foam metal layer.

[0037] Specifically, in this embodiment, the foaming material comprises a foaming agent containing 1% to 2% TiH2 by mass, and the metal powder is aluminum powder. Alternatively, the foaming material may contain a foaming agent containing 2% to 3% SrCO3 by mass, and the metal powder may be iron powder. Alternatively, other foaming materials may be used to fill the inner tube 3, as long as the foaming agent in the foam material is distributed within the annular gap in a radially decreasing mass fraction from the inner wall of the metal outer tube 1 to the outer wall of the metal inner tube 2.

[0038] For example, three layers of embedded tubes 3 are radially arranged in the annular gap, namely, the first layer of embedded tubes 3, the second layer of embedded tubes 3 and the third layer of embedded tubes 3 from the outside to the inside, and the mass fractions of the foaming agent TiH2 filled in the three layers of embedded tubes 3 are 2%, 1.5% and 1% respectively; or, the mass fractions of the foaming agent SrCO3 filled in the three layers of embedded tubes 3 are 3%, 2.5% and 2% respectively.

[0039] Specifically, in step S600, the temperature for heating the third composite pipe blank is 650-1350℃, and the foaming material is foamed for 5-10 minutes. For example, the temperature for heating the third composite pipe blank can be 650℃, 800℃, 950℃, 1000℃, 1200℃, 1350℃, etc., and the foaming time of the foaming material can be 5 minutes, 6 minutes, 8 minutes, 10 minutes, etc. Since the melting point of the metal powder in the foaming material is usually high, a foaming temperature greater than 650℃ can ensure that the metal material is partially melted or semi-melted, the melt viscosity is reduced to provide the flowability basis for the uniform dispersion and expansion of the bubbles, and the uniformity of the pores and the structural stability of the porous structure are ensured. When the foaming temperature is less than 1350℃, the risk of material composition segregation and pore structure collapse of the foamed metal layer due to excessive volatilization and decomposition of the metal melt at high temperature is avoided, and the uniformity of the pores and the structural stability of the porous structure are ensured. Preferably, when the foaming material is TiH2 and Al powder mixed uniformly at room temperature and normal pressure, and then loaded into the embedded pipe 3 for cold extrusion, and the foaming material is blocked in the embedded pipe 3 by the iron block, the foaming temperature of the foaming process is 650℃, and the foaming time is 10 minutes. When the foaming material is SrCO3 and Fe powder mixed uniformly at room temperature and normal pressure, and then loaded into the embedded pipe 3 for cold extrusion, and the foaming material is blocked in the embedded pipe 3 by the iron block, the foaming temperature of the foaming process is 1350℃, and the foaming time is 5 minutes. The operator can select different foaming temperatures and foaming times according to the actual addition of the foaming material, as long as the uniformity of the foamed metal layer after foaming is ensured.

[0040] Specifically, in the present embodiment, the packaging plate comprises metal and / or resin. For example, the packaging plate can be an iron block, an aluminum block or other metal, as long as it can ensure good metallurgical bonding between the packaging plate and the open end of the embedded pipe 3, and can complete the blocking. Of course, the resin has good fluidity before solidification, and can form close physical contact on the metal surface to prevent leakage of the foaming material in the embedded pipe 3.

[0041] Specifically, in this embodiment, the outer metal tube 1 and the inner metal tube 2 are both alloy steel tubes or aluminum alloy tubes; the multiple embedded tubes 3 are one or more of iron tubes, aluminum tubes, and stainless steel tubes. The outer metal tube 1 and the inner metal tube 2 can both be alloy steel tubes, aluminum alloy tubes, or other metal tubes, and the embedded tubes 3 can be iron tubes, aluminum tubes, or other metal tubes, as long as the resulting foamed metal layer can form a good metallurgical bond with the outer metal tube 1 and the inner metal tube 2. For example, the metal outer tube 1 is an aluminum alloy tube with an outer diameter of 180 mm to 220 mm (preferably, the outer diameter of the metal outer tube 1 is 200 mm) and an inner diameter of 160 mm to 200 mm (preferably, the inner diameter of the metal outer tube 1 is 180 mm), and the metal inner tube 2 is an aluminum alloy tube with an outer diameter of 50 mm to 70 mm (preferably, the outer diameter of the metal inner tube 2 is 60 mm) and an inner diameter of 40 mm to 60 mm (preferably, the inner diameter of the metal inner tube 2 is 50 mm); or the metal outer tube 1 is an aluminum alloy tube with an outer diameter of 180 mm to 220 mm (preferably, the inner diameter of the metal inner tube 2 is 180 mm). The outer tube 1 is an alloy steel tube with an outer diameter of 200 mm and an inner diameter of 60 mm to 200 mm (preferably, the inner diameter of the metal outer tube 1 is 180 mm), and the metal inner tube 2 is an alloy steel tube with an outer diameter of 50 mm to 70 mm (preferably, the outer diameter of the metal inner tube 2 is 60 mm) and an inner diameter of 40 mm to 60 mm (preferably, the inner diameter of the metal inner tube 2 is 50 mm). It is sufficient as long as the radial distance between the inner wall of the metal outer tube 1 and the outer wall of the metal inner tube 2 of the tube blank material obtained by riveting or other processing methods is 60 mm.

[0042] Specifically, the embedded tube 3 can be only one of an iron tube, an aluminum tube, and a stainless steel tube; the embedded tube 3 can also be an iron tube and an aluminum tube, or the embedded tube 3 can be an iron tube, an aluminum tube, and a stainless steel tube at the same time.

[0043] like Figure 2 and Figure 3 As shown, for example, when only iron tubes and aluminum tubes are selected for the embedded tubes 3, the embedded tubes of each layer are distributed in a manner in which the iron tubes and the aluminum tubes are placed alternately. In this arrangement, since the thermal expansion coefficients of the iron tubes and the aluminum tubes are quite different, an alternating arrangement is adopted so that under the temperature change during heating in step S600, the expansion / contraction of the iron tubes and the aluminum tubes can be restrained from each other, thereby reducing the thermal stress concentration of the overall structure of the foamed metal layer during the foaming process and reducing the risk of cracking at the connection between the iron tubes and the aluminum tubes.

[0044] When the embedded tube 3 has an iron tube, an aluminum tube and a stainless steel tube, if three layers are arranged radially in the annular gap, the annular gap is distributed from the outside to the inside as stainless steel tube, iron tube and aluminum tube; if four layers are arranged radially in the annular gap, the annular gap is distributed from the outside to the inside as stainless steel tube, iron tube, aluminum tube and stainless steel tube. With such arrangement, since the stainless steel tube located in the outer layer or the inner layer has good hardness and stable performance at high temperature, it can withstand external mechanical collision, friction or extrusion, avoids the risk of deformation or damage of the internal tube, and extends the service life of the overall structure of the gradient vibration damping composite tube.

[0045] like Figures 2-4 As shown, the embodiment of the present invention also provides another method for manufacturing a gradient vibration damping composite tube, including: Step S100 ′: providing a metal outer tube 1, a metal inner tube 2, a base, and a plurality of metal solid rods, wherein one end of the metal outer tube 1 and the metal inner tube 2 are fixed by the base, and an annular filling cavity is formed between the metal outer tube 1, the metal inner tube 2, and the base; In step S200', a plurality of metal solid rods are tightly arranged in an annular filling cavity; wherein the plurality of metal solid rods have at least two different diameters, and the diameters of the plurality of metal solid rods decrease layer by layer in the direction from the inner wall of the metal outer tube to the outer wall of the metal inner tube; or, the metal solid rods with smaller diameters are distributed close to the outer wall of the metal inner tube and close to the inner wall of the metal outer tube, and the metal solid rods with larger diameters are distributed between the two layers of metal solid rods with smaller diameters along the circumferential direction.

[0046] In step S300', foaming materials with different foaming agent mass fractions are filled into the gaps between adjacent metal solid rods. The foaming materials include foaming agent and metal powder, so that the foaming agent mass fraction of the foaming material in the annular filling cavity decreases layer by layer along the radial direction from the inner wall of the metal outer tube 1 to the outer wall of the metal inner tube 2. Specifically, the foaming agent and metal powder are fully mixed and then loaded into the gaps between adjacent metal solid rods.

[0047] Step S400', using a packaging plate to seal the open end of the annular filling cavity to obtain a fourth composite tube blank; Step S500 ′, performing internal spinning on the fourth composite tube to a target wall thickness to obtain a fifth composite tube; In step S600', the fifth composite tube blank is heated to foam the foaming material, thereby forming a gradient vibration damping composite tube having a foam metal layer. Specifically, during the heating and foaming process of the fifth composite tube blank, the fifth composite tube blank can be placed in a mold. For example, the mold can also employ a cavity structure formed by a sleeved outer metal tube and an inner metal tube. The outer wall diameter of the fifth composite tube blank is the same as the inner diameter of the outer metal tube, and the inner wall diameter of the fifth composite tube blank is the same as the outer diameter of the inner metal tube. The cavity structure formed by the sleeved outer metal tube and the inner metal tube constrains the surface of the fifth composite tube blank, preventing expansion and deformation of the fifth composite tube blank during the heating and foaming process.

[0048] Compared with the traditional method of obtaining a composite tube by using a foam metal interlayer with a unified structure, the present application arranges a plurality of metal solid rods closely in an annular filling cavity, so that a gap for filling the foaming material is formed in the annular filling cavity with a stable radial distribution. By distributing foaming agents of different mass fractions in the gaps between the plurality of metal solid rods and sealing them, the plurality of metal solid rods constrain the position of the foaming material in the annular filling cavity, so that the foaming material is evenly distributed in the annular filling cavity, and after foaming, the stability of the gradient distribution of different foaming structures in the composite tube is improved; then it is spun to the target wall thickness, and finally heated and foamed, so that the formed The foamed metal layer is used as the core layer of the composite tube. Due to the different mass fractions of the foaming agent, the porosity formed after foaming is different, and the multiple metal solid rods have different diameters, and the metal solid rods with different diameters are distributed differently along the radial direction of the annular filling cavity. Therefore, the porosity of the obtained foamed metal layer can be distributed in a gradient between the metal inner tube 2 and the metal outer tube 1. Among them, when the multiple metal solid rods have at least two different diameters, in the direction from the inner wall of the metal outer tube 1 to the outer wall of the metal inner tube 2, the diameters of the multiple metal solid rods decrease layer by layer. The larger the diameter, the larger the gap between adjacent metal solid rods, and the inner spinning and After foaming, the gaps formed at the metal solid rods with larger diameters are larger and the porosity is higher. On the contrary, the smaller the diameter, the smaller the gap between adjacent metal solid rods. After internal spinning and foaming, the gaps formed at the metal solid rods with smaller diameters are smaller and the porosity is lower. The mass fraction of the foaming agent filled from the outside to the inside is gradually reduced, so that the porosity of the foam metal layer decreases in a step-by-step manner from the inner wall of the metal outer tube 1 to the outer wall of the metal inner tube 2 along the radial direction (that is, the porosity of the outer layer is higher and the porosity of the inner layer is lower). The gradient vibration damping composite tube forms a gradient interception of the sound wave / vibration energy at different radial positions, so that the gradient vibration damping composite tube can effectively prevent the sound wave / vibration energy from being lost. The overall porosity of the shaped filling cavity is relatively large, avoiding the performance limitations of a single porosity structure. When the gradient vibration damping composite tube is subjected to external force vibration, the higher porosity structure located in the outer layer provides elastic buffering, and the pores of the porous structure can disperse and absorb part of the vibration energy. The metal solid rod as the skeleton of the porous structure provides support. Compared with the metal solid rod of the same diameter and the foam metal layer formed by the same mass fraction of the foaming agent material, the problem of weak mechanical properties of the single porosity material in the composite tube is avoided, thereby reducing the vibration amplitude of the sound wave / vibration transmitted to the inside of the tube wall and improving the sound absorption and vibration reduction performance of the gradient vibration damping composite tube. When multiple metal solid rods have at least two different diameters, the metal solid rods with smaller diameters are distributed close to the outer wall of the metal inner tube and close to the inner wall of the metal outer tube, and the metal solid rods with larger diameters are distributed between the two layers of metal solid rods with smaller diameters along the circumferential direction, the gradient vibration damping composite tube constructs different functional layers at different radial positions. The outer layer and the inner layer close to the foam metal layer have smaller diameters of the metal solid rods, so that the gaps between adjacent metal solid rods are smaller and the amount of foaming material filled is less. Multiple metal solid rods with smaller diameters can provide good structural support and barrier capabilities as supporting skeletons; the middle layer close to the foam metal layer has larger diameters of the metal solid rods, so that the gaps between adjacent metal solid rods are smaller. While the larger, larger diameter metal solid rod can provide structural support, the larger gap foam can be filled with more foaming material, which provides sufficient expansion space for the foaming material. The pores of the porous structure can disperse and absorb part of the vibration energy. The mass fraction of the foaming agent filled from the outside to the inside decreases layer by layer, so that the porosity of the foam metal layer decreases in a step-by-step manner from the inner wall of the metal outer tube to the outer wall of the metal inner tube along the radial direction, forming a gradient interception of sound waves / vibration energy. Compared with the foam metal layer formed by the metal solid rod of the same diameter and the foaming agent material of the same mass fraction, the problem of weak mechanical properties of single porosity material in the composite pipe is avoided, and the balance between the strength and vibration reduction and sound absorption performance of the gradient vibration damping composite pipe is ensured.

[0049] For example, Figure 2 As shown, three layers of solid metal rods are radially arranged within the annular filling cavity. From the outside to the inside, they are the first layer of solid metal rods, the second layer of solid metal rods, and the third layer of solid metal rods. The diameters of the three layers of solid metal rods decrease from the outside to the inside. The solid metal rods in each layer are closely arranged along the circumference. The gaps between the solid metal rods in the same layer are filled with a foaming material having the same mass fraction of the foaming agent. The mass fraction of the foaming agent in the foaming material within the annular filling cavity decreases from the outside to the inside. Of course, the solid metal rods within the annular filling cavity can also be arranged radially within the annular filling cavity with two, four, or other layers of solid metal rods having different diameters.

[0050] For example, Figure 3As shown, four layers of metal solid rods are radially arranged in the annular filling cavity. From the outside to the inside, they are the first layer of metal solid rods, the second layer of metal solid rods, the third layer of metal solid rods, and the fourth layer of metal solid rods. The diameter of the first layer of metal solid rods is the same as the diameter of the fourth layer of metal solid rods, and the diameter of the second layer of metal solid rods is the same as the diameter of the third layer of metal solid rods. The diameter of the first layer of metal solid rods is smaller than the diameter of the second layer of metal solid rods. Each layer of metal solid rods is closely arranged along the circumference, and the gaps between the metal solid rods in the same layer are filled with the same mass fraction of the foaming agent in the foaming material. The mass fraction of the foaming agent in the foaming material in the annular filling cavity decreases from the outside to the inside. Of course, two, three, five, or other layers of metal solid rods with different diameters can also be arranged radially in the annular filling cavity.

[0051] Specifically, in this embodiment, the fifth composite tube blank is heated to a temperature of 650°C to 1350°C, and the foaming time of the foaming material is 5 minutes to 10 minutes. For example, the fifth composite tube blank can be heated to a temperature of 650°C, 800°C, 950°C, 1000°C, 1200°C, 1350°C, etc., and the foaming time of the foaming material can be 5 minutes, 6 minutes, 8 minutes, 10 minutes, etc. Since the melting point of the metal powder in the foaming material is generally high, a foaming temperature greater than 650°C can ensure that the metal material partially reaches a molten or semi-molten state, and the reduced melt viscosity provides a fluidity foundation for uniform dispersion and expansion of bubbles, thereby ensuring the pore uniformity and structural stability of the porous structure. A foaming temperature less than 1350°C avoids the risk of excessive volatilization and decomposition of the metal melt at high temperatures, which may cause segregation of the foamed metal layer's material composition and collapse of the pore structure, thereby ensuring the pore uniformity and structural stability of the porous structure. Preferably, when the foaming material is TiH2 and Al powder, mixed uniformly at room temperature and pressure, then filled into the gap between adjacent metal solid bars and cold extruded, and the open end of the annular filling cavity is sealed by a sealing plate, the sealing plate can be made of alloy steel, and the foaming temperature during the foaming process is 650°C and the foaming time is 10 minutes. When the foaming material is SrCO3 and Fe powder, mixed uniformly at room temperature and pressure, then filled into the gap between adjacent metal solid bars and cold extruded, and the open end of the annular filling cavity is sealed by a sealing plate, the sealing plate can be made of alloy steel, and the foaming temperature during the foaming process is 1350°C and the foaming time is 5 minutes. The operator can select different foaming temperatures and foaming times based on the actual foaming material added, as long as the foaming uniformity of the foamed metal layer formed after foaming is ensured.

[0052] Specifically, in this embodiment, the solid metal rod is an iron rod or an aluminum rod; the encapsulation plate comprises metal and / or resin; and the metal outer tube 1 and the metal inner tube 2 are both alloy steel tubes or aluminum alloy tubes. The material and diameter of the solid metal rod are selected with reference to the material and diameter of the embedded tube 3 in the first embodiment. The encapsulation plate, metal outer tube 1, and metal inner tube 2 can be selected as long as they meet the processing requirements of the gradient vibration damping composite tube. The description of the encapsulation plate, metal outer tube 1, and metal inner tube 2 in the first embodiment is referenced and will not be repeated here.

[0053] Specifically, in this embodiment, the foaming material comprises a foaming agent containing 1% to 2% TiH2 by mass, and the metal powder is aluminum powder; alternatively, the foaming material comprises a foaming agent containing 2% to 3% SrCO3 by mass, and the metal powder is iron powder. Of course, the foaming material may also be a mixture of other foaming agents and metal powders, and this is not limited here.

[0054] Exemplarily, three layers of metal solid rods are radially arranged in the annular filling cavity, namely the first layer of metal solid rods, the second layer of metal solid rods and the third layer of metal solid rods from the outside to the inside, and the mass fractions of the foaming agent TiH2 filled in the gaps between the three layers of metal solid rods along the radial direction of the annular filling cavity from the outside to the inside are 2%, 1.5%, and 1% respectively; or, the mass fractions of the foaming agent SrCO3 in the gaps between the three layers of metal solid rods along the radial direction of the annular filling cavity from the outside to the inside are 3%, 2.5%, and 2% respectively.

[0055] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for manufacturing a gradient vibration damping composite pipe, characterized in that: include: Providing a metal outer tube, a metal inner tube and a plurality of embedded tubes; Encapsulating a foaming material in each of the embedded tubes, wherein the foaming material includes a foaming agent and metal powder, to obtain a plurality of embedded tubes with different foaming agent mass fractions; The plurality of embedded tubes are tightly arranged in an annular gap formed by the sheathing of the metal outer tube and the metal inner tube, so that the plurality of embedded tubes are distributed in the annular gap in a manner such that the mass fraction of the foaming agent decreases layer by layer along the radial direction from the inner wall of the metal outer tube to the outer wall of the metal inner tube, thereby obtaining a first composite tube blank; wherein the plurality of embedded tubes have at least two different tube diameters, and the tube diameters of the plurality of embedded tubes decrease layer by layer in the direction from the inner wall of the metal outer tube to the outer wall of the metal inner tube; alternatively, the embedded tubes with smaller tube diameters are distributed close to the outer wall of the metal inner tube and close to the inner wall of the metal outer tube, and the embedded tubes with larger tube diameters are distributed circumferentially between two layers of the embedded tubes with smaller tube diameters; Using a packaging plate to seal the open end of the annular gap to obtain a second composite tube blank; performing internal spinning on the second composite tube blank to a target wall thickness to obtain a third composite tube blank; The third composite tube blank is heated to foam the foaming material, thereby obtaining a gradient vibration-damping composite tube having a foam metal layer.

2. The method for manufacturing a gradient vibration damping composite pipe according to claim 1, characterized in that: After closely arranging the plurality of embedded tubes in the annular gap formed by the metal outer tube and the metal inner tube, and before using the packaging plate to cover the open end of the annular gap, the manufacturing method further includes: filling metal chips into the outer wall gaps of the plurality of embedded tubes.

3. The method for manufacturing a gradient vibration damping composite pipe according to claim 1 or 2, characterized in that: The wall thickness of the embedded tube is 2 mm to 4 mm, and the inner diameter of the embedded tube is 10 mm to 30 mm.

4. The method for manufacturing a gradient vibration damping composite pipe according to claim 1, characterized in that: The temperature for heating the third composite tube blank is 650° C. to 1350° C., and the foaming time of the foaming material is 5 min to 10 min.

5. The method for manufacturing a gradient vibration damping composite pipe according to claim 1, characterized in that: The packaging plate includes metal and / or resin; The metal outer tube and the metal inner tube are both alloy steel tubes or aluminum alloy tubes; The embedded tube is one or more of an iron tube, an aluminum tube, and a stainless steel tube.

6. The method for manufacturing a gradient vibration damping composite pipe according to claim 1, characterized in that: The foaming agent in the foaming material is TiH2 with a mass fraction of 1% to 2%, and the metal powder is aluminum powder; Alternatively, the foaming agent in the foaming material is SrCO3 with a mass fraction of 2% to 3%, and the metal powder is iron powder.

7. A method for manufacturing a gradient vibration damping composite pipe, characterized in that: include: A metal outer tube, a metal inner tube, a base, and a plurality of metal solid rods are provided, wherein one end of the metal outer tube and the metal inner tube are fixed by the base, and an annular filling cavity is formed between the metal outer tube, the metal inner tube, and the base; The plurality of metal solid rods are tightly arranged in the annular filling cavity; wherein the plurality of metal solid rods have at least two different diameters, and the diameters of the plurality of metal solid rods decrease layer by layer in the direction from the inner wall of the metal outer tube to the outer wall of the metal inner tube; or, the metal solid rods with smaller diameters are distributed close to the outer wall of the metal inner tube and close to the inner wall of the metal outer tube, and the metal solid rods with larger diameters are distributed circumferentially between two layers of metal solid rods with smaller diameters; Filling the gaps between adjacent metal solid rods with foaming materials having different foaming agent mass fractions, the foaming materials comprising a foaming agent and metal powder, such that the foaming agent mass fraction of the foaming material in the annular filling cavity decreases radially from the inner wall of the metal outer tube to the outer wall of the metal inner tube. Using a packaging plate to seal the open end of the annular filling cavity to obtain a fourth composite tube blank; performing internal spinning on the fourth composite tube blank to a target wall thickness to obtain a fifth composite tube blank; The fifth composite tube blank is heated to foam the foaming material to form a gradient vibration-damping composite tube with a foam metal layer.

8. The method for manufacturing a gradient vibration damping composite pipe according to claim 7, characterized in that: The diameter of the metal solid rod is 10 mm to 30 mm.

9. The method for manufacturing a gradient vibration damping composite pipe according to claim 7, characterized in that: The fifth composite tube blank is heated at a temperature of 650° C. to 1350° C., and the foaming time of the foaming material is 5 min to 10 min.

10. The method for manufacturing a gradient vibration damping composite pipe according to claim 7, characterized in that: The metal solid rod is an iron rod or an aluminum rod; The packaging plate includes metal and / or resin; The metal outer tube and the metal inner tube are both alloy steel tubes or aluminum alloy tubes.

11. The method for manufacturing a gradient vibration damping composite pipe according to claim 7, characterized in that: The foaming agent in the foaming material is TiH2 with a mass fraction of 1% to 2%, and the metal powder is aluminum powder; Alternatively, the foaming agent in the foaming material is SrCO3 with a mass fraction of 2% to 3%, and the metal powder is iron powder.

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