Non-vacuum brazing connection method for high-temperature-resistant space truss rod pieces

Abstract

The invention provides a non-vacuum brazing connection method for high-temperature-resistant space truss rod pieces. The non-vacuum brazing connection method comprises the steps that space truss nodes are fixed to a tool; one end of each space truss rod piece is coated with welding flux, the space truss rod pieces coated with the welding flux are arranged in the space truss nodes in a sleeving mode, it is guaranteed that the welding flux fills the matched cavities, and the space position precision of the space truss rod pieces is guaranteed through a tool; covering the brazing connection part with a quartz isolation cover, and introducing inert protective gas; a non-contact induction brazing device is used for conducting electromagnetic induction heating on the brazing connection part; and the non-contact induction brazing device is removed, and inert protective gas is continuously introduced into the quartz isolation hood till the connector is cooled to the room temperature. By means of the method, the service environment temperature of the space truss structure ranges from 500 DEG C to 1100 DEG C, the space truss rod piece connecting strength is not lower than 95% of base metal, and the space truss rod piece connecting brazing process is not limited by the vacuum environment.

Description

Technical Field

[0001] This invention belongs to the field of brazing technology, specifically relating to a non-vacuum, non-contact brazing connection method for high-temperature resistant space truss members. Background Technology

[0002] Space truss structures are highly efficient and widely used in the aerospace field, particularly in lightweight, large-span space building structures. The connection of space truss members is crucial to the truss's load-bearing capacity and is also a weak point during service. Currently, widely used space truss structures generally do not exceed 500°C, and their material systems are mainly resin-based composites, carbon steel, and aluminum alloys. Their connections primarily rely on adhesive bonding, argon arc welding, and threaded connections. Consequently, the overall performance indicators of the core structure, such as the strength of the connection interface, the added weight of the connection joint, and the dimensional accuracy of the assembly, are not optimal.

[0003] In the context of high-speed flight, the space truss load-bearing structure of an aircraft faces an operating temperature range of 500 to 1100°C. Under the constraint of lightweighting, the comprehensive performance indicators of the core structure achieved by traditional technical means cannot meet the requirements of high-speed aircraft. Therefore, it is necessary to develop new high-temperature resistant space truss member connection methods. Summary of the Invention

[0004] The purpose of this invention is to provide a non-vacuum brazing connection method for high-temperature resistant space truss members, so that the service environment temperature of the space truss structure is 500-1100℃, the connection strength of the space truss members is not less than 95% of the base material, and the brazing process of the space truss members is not limited by the vacuum environment.

[0005] To address the technical problems existing in the prior art, this invention provides a non-vacuum brazing connection method for high-temperature resistant space truss members. The structural components to be brazed are space truss nodes and space truss members. The space truss nodes include multiple connecting pipes in different directions, and each connecting pipe is used for welding connection to a space truss member. The brazing connection includes the following steps:

[0006] Fix the spatial truss nodes on the tooling;

[0007] Solder is applied to the ends of the space truss nodes or space truss members to be connected. The space truss nodes are then connected to the space truss members, and the truss members are fixed with tooling.

[0008] Place a quartz shield over the brazing connection and introduce an inert protective gas.

[0009] A non-contact induction brazing device is installed outside the quartz isolation cover at the corresponding brazing connection point to perform electromagnetic induction heating.

[0010] Control the induction heating current and heating time to complete the brazing. Remove the non-contact induction brazing device and continue to circulate inert protective gas into the quartz isolation cover until it cools to the removal temperature. Remove the quartz isolation cover.

[0011] The space truss nodes and space truss members are made of titanium-containing materials; the solder metal composition is Ti-25Cu-10Zr-6Ni-xMo, where x = 0.5 to 1.5.

[0012] Furthermore, the space truss nodes are made of pure titanium or titanium alloy; the space truss members are made of continuous SiC fiber reinforced titanium-based composite material with a fiber volume fraction of 45% to 55%.

[0013] Furthermore, the solder is in paste form and includes metallic and non-metallic components, wherein the non-metallic component is terpineol, and the mass fraction of the metallic component in the solder is 60% to 80%.

[0014] Furthermore, the amount of solder used is 5 to 10 times the volume of the cavity at the welding position of the space truss member and space truss node.

[0015] Furthermore, the outer diameter of the space truss member is the same as the outer diameter of the connecting pipe of the space truss node, the inner diameter of the space truss member is larger than the inner diameter of the connecting pipe of the space truss node, and a recessed step is provided at the end of the connecting pipe of the space truss node to be connected. The outer diameter of the step is smaller than the inner diameter of the space truss member, and the space truss member is sleeved on the step.

[0016] The difference between the outer diameter of the step and the inner diameter of the space truss member is 0.06mm to 0.12mm, and the length of the step is 1 / 2 to 1 / 2 of the outer diameter of the space truss member.

[0017] Furthermore, the quartz isolation cover includes two semi-enclosed covers, which are connected by a brazing joint and are not sealed to each other; each cover includes an opening for air intake and air exhaust respectively.

[0018] Furthermore, the induction coil used in the non-contact induction brazing device is a semi-enclosed type, and there are two semi-enclosed induction coils that cover the brazing connection part from both sides.

[0019] Alternatively, the induction coil used in the non-contact induction brazing device is a planar type, with two planar induction coils arranged relatively parallel to each other on the outside of the brazing connection.

[0020] Furthermore, the induction coil is fixed by a bracket, and the bracket drives the induction coil to rotate around the brazed connection part;

[0021] The distance between the induction coil and the space truss node is 10mm to 30mm;

[0022] During the welding process, the induction heating current is 400A to 600A, and the heating time is 60s to 180s. After the welding process is completed, the induction heating current drops to 100A to 200A and lasts for 10s to 20s.

[0023] Furthermore, multiple sets of the aforementioned space truss nodes and space truss members are welded simultaneously.

[0024] Furthermore, the inert gas is nitrogen or argon, and the gas flow rate is 10L / min to 15L / min; the dismantling temperature is 300℃.

[0025] The beneficial effects of this invention compared to the prior art are as follows:

[0026] This invention provides a non-vacuum brazing connection method for high-temperature resistant space truss members, which has the following characteristics:

[0027] 1. A brazing flux material system that is compatible with materials such as titanium alloys, titanium-based composites, metal compounds, or high-temperature alloys, and can be adapted to service environment temperatures of 500 to 1100°C, with a connection strength of not less than 95% of the base material.

[0028] 2. This method of connecting space truss members offers strong process feasibility, is not limited by the vacuum environment during construction, and the dimensions of the space truss structure that can be assembled are not limited by the cavity of the vacuum brazing furnace.

[0029] 3. The fabrication of the connection of the space truss structure can be carried out simultaneously in multiple locations, which can significantly shorten the fabrication cycle.

[0030] 4. The positional accuracy of the space truss nodes and members is ensured by special tooling, which guarantees that the dimensional accuracy of the space truss assembly is better than 1mm.

[0031] Using the method of this invention, the service environment temperature of the space truss structure can be between 500 and 1100°C, the connection strength of the space truss members is not less than 95% of the base material, the additional weight of the space truss member connection joints is negligible, the dimensional accuracy of the space truss member connection joint assembly is better than 1 mm, and the brazing process of the space truss member connection is not limited by the vacuum environment or the size of the vacuum furnace cavity. Attached Figure Description

[0032] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0033] Figure 1 A schematic diagram of a non-vacuum, non-contact brazing connection for high-temperature resistant space truss members provided in a specific embodiment of the present invention;

[0034] Figure 2 A schematic diagram of solder arrangement provided for a specific embodiment of the present invention;

[0035] Figure 3 A schematic diagram of the non-vacuum non-contact brazing heating area and isolation gas protection assembly provided for a specific embodiment of the present invention;

[0036] The above figures include the following reference numerals:

[0037] 1. Electromagnetic induction heating device; 2. Quartz isolation cover; 3. Space truss node; 4. Space truss member; 5. Solder. Detailed Implementation

[0038] Specific embodiments of the present invention will now be described in detail. In the following description, specific details are set forth for purposes of explanation and not limitation, in order to aid in a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced in other embodiments departing from these specific details.

[0039] It should be noted that, in order to avoid obscuring the invention with unnecessary details, only the device structure and / or processing steps closely related to the solution of the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0040] This invention provides a non-vacuum, non-contact brazing connection method for high-temperature resistant space truss members, such as... Figures 1-3 As shown, the structural components to be connected are space truss node 3 and space truss member 4. The space truss node 3 includes multiple connecting pipes in different directions. Each connecting pipe is used for welding connection to a space truss member 4. The brazing connection method includes the following steps:

[0041] Step 1: Fix spatial truss node 3 on the special tooling to ensure that the positioning accuracy of spatial truss node 3 meets the requirements;

[0042] Step 2: Apply solder 5 to one end of the space truss member 4, which is made of continuous SiC fiber reinforced titanium-based composite material. Then, insert the solder-coated space truss member 4 into a connecting tube of the space truss node 3 to ensure that the solder 5 fills the mating cavity. The spatial position accuracy of the space truss member 4 is guaranteed by special tooling.

[0043] Step 3: Cover the brazing connection with the quartz isolation cover 2 and introduce inert protective gas. The pressure of the protective gas inside the quartz isolation cover is higher than the outside atmospheric pressure to prevent outside air from entering the isolation cover, thereby forming a good inert gas protective environment at the brazing connection to prevent joint oxidation.

[0044] Step 4: Use a non-contact induction brazing device 1 to electromagnetically induction heat the joint, control the induction heating current and heating time, and ensure that the solder temperature meets the requirements of the brazing process window.

[0045] Step 5: Remove the non-contact induction brazing device 1, and continue to circulate inert protective gas into the quartz isolation cover 2 until the connection joint cools to 300°C. Remove the quartz isolation cover, and the connection of the space truss members is now complete.

[0046] Preferably, the material of space truss node 3 is pure titanium or titanium alloy.

[0047] Preferably, the space truss member 4 is made of continuous SiC fiber reinforced titanium-based composite material, with a fiber volume fraction of 45% to 55%.

[0048] Preferably, solder 5 is in paste form, wherein the metallic component is Ti-25Cu-10Zr-6Ni-xMo (mass fraction, %), x = 0.5~1.5, and the non-metallic component is terpineol. The mass fraction of the metallic component in the solder is 60%~80%. Mo in the solder exists in the form of micron-sized particles. Mo has superior high-temperature resistance, and it can form solid solutions with Ti, Cu, and Zr, effectively preventing weld embrittlement.

[0049] Preferably, the amount of solder is 5 to 10 times the volume of the cavity between the space truss member 4 and the space truss node 3. This amount can ensure that the solder fills the gap between the space truss member and the space truss node, and can also ensure the formation of a smooth transition brazing angle (part of the solder enters the interior of the space truss member 4), which helps to reduce the welding stress of the smaller joint.

[0050] Preferably, the fitting depth between the space truss member 4 and the space truss node 3 is 1 / 2 to 1 of the outer diameter of the space truss member 4; the difference between the inner diameter of the space truss member 4 and the outer diameter of the space truss node 3 at the weld is 0.06 mm to 0.12 mm. This assembly gap ensures both the spatial positioning accuracy of the structure and the penetration and filling of the entire area to be connected by the weld.

[0051] Preferably, the quartz isolation enclosure comprises two semi-enclosed enclosures, which are joined together to surround the brazed connection, and the two enclosures are not sealed together. Each enclosure includes an opening for air intake and exhaust. The two enclosures are directly fixed to the outside of the space truss node 3 and the space truss member 4, simplifying the installation method. The joint of the two semi-enclosed enclosures protects the welded area from oxidation, and the fact that the two enclosures are not sealed allows for rapid gas escape, preventing excessive pressure.

[0052] Preferably, the induction coil used in the non-contact induction brazing device 1 is semi-enclosed or planar, which facilitates easy removal from the connection between the space truss member 4 and the space truss node 3. The induction coil is set on the outside of the isolation cover 2 and fixed on the support. The support can be rotated by a motor, controlling the speed and direction of rotation to adjust the heating efficiency and uniformity.

[0053] Preferably, there are two semi-enclosed induction coils that cover the brazing connection from both sides; and two planar induction coils that are arranged relatively parallel to each other on the outside of the brazing connection. With this configuration and rotation control, uniform heating can be achieved.

[0054] Preferably, the distance between the induction coil and the spatial truss node 3 is 10mm to 30mm. During brazing, the induction coil rotates around the weld joint to ensure that the spatial truss rod 4 and the spatial truss node 3 are heated evenly, avoiding deformation caused by uneven heating that could lead to insufficient component precision. During welding, the induction heating current is 400A to 600A, and the heating time is 60s to 180s. After the welding process is completed, the induction heating current drops to 100A to 200A and lasts for 10s to 20s, allowing the welded joint to cool slowly and avoiding excessive welding stress.

[0055] Preferably, the inert gas is nitrogen or argon, and the gas flow rate is 10L / min to 15L / min. In addition, when the welded joint cools to 300°C, the quartz isolation cover is removed, which can ensure both the weldability of the structure and the welding efficiency.

[0056] Preferably, in order to improve work efficiency, multiple sets of space truss nodes and space truss members can be welded in parallel at the same time.

[0057] This invention provides a non-vacuum, non-contact brazing method for heat-resistant, high-temperature space truss members. This method enables space truss structures to operate in environments ranging from 500 to 1100°C, maintaining a connection strength of at least 95% of the base material. The added weight of the connection joints is negligible, and the dimensional accuracy of the joint assembly is better than 1 mm. Furthermore, the brazing process is not limited by vacuum environments or the size of vacuum furnace cavities. This invention is suitable for high-quality connections of high-temperature space truss members.

[0058] The technical solution of the present invention will be described in detail below with reference to two specific embodiments.

[0059] Example 1:

[0060] Step 1: Fix space truss node 3, made of TA15 material, onto a special tooling. The inner diameter of the node connection is 16mm and the outer diameter is 24mm. Machin a step with a width (d) of 2mm and a height (h) of 18mm at the end to be welded. Apply 0.5mL of Ti-25Cu-10Zr-6Ni-0.8Mo (mass fraction) solder to the end of space truss node 3 to be connected.

[0061] Step 2: The material of the space truss member 4 is a titanium-based composite material reinforced with continuous SiC fiber with a volume fraction of 20%. Its outer diameter is 24mm and its inner diameter is 20mm. Insert the end of the space truss node 3 coated with solder into the space truss member 4, and use special tooling to ensure the spatial position accuracy of the truss member 4.

[0062] Step 3: Place the quartz isolation cover 2 over the brazing connection and introduce nitrogen gas at a flow rate of 10L / min.

[0063] Step 4: Use a non-contact induction brazing device 1 to perform electromagnetic induction heating on the connection joint. The induction coil in the non-contact induction brazing device 1 is semi-enclosed, the distance between the coil and the spatial truss node 3 is 10mm, the induction heating current is 450A, and the heating time is 130s.

[0064] Step 5: Remove the non-contact induction brazing device 1 and continue to circulate inert protective gas into the quartz isolation cover 2 until the connection joint cools to 300°C. At this point, the connection of the space truss members is complete.

[0065] Example 2:

[0066] Step 1: Fix space truss node 3, made of TA15 material, on a special tooling. The inner diameter of the node connection is 16mm and the outer diameter is 24mm. Machin a step with a width (d) of 2mm and a height (h) of 18mm at the end to be welded. Apply 0.5mL of Ti-25Cu-10Zr-6Ni-1.2Mo (mass fraction) solder to the end of space truss node 3 to be connected.

[0067] Step 2: The material of the space truss member 4 is a titanium-based composite material reinforced with continuous SiC fiber with a volume fraction of 20%. Its outer diameter is 24mm and its inner diameter is 20mm. Insert the end of the space truss node 3 coated with solder into the space truss member 4, and use special tooling to ensure the spatial position accuracy of the truss member 4.

[0068] Step 3: Place the quartz isolation cover 2 over the brazing connection and introduce nitrogen gas at a flow rate of 15L / min.

[0069] Step 4: Use a non-contact induction brazing device 1 to perform electromagnetic induction heating on the connection joint. In the non-contact induction brazing device 1, the induction coil is semi-enclosed, the distance between the coil and node 3 is 20mm, the induction heating current is 550A, and the heating time is 120s.

[0070] Step 5: Remove the non-contact induction brazing device 1 and continue to circulate inert protective gas into the quartz isolation cover 2 until the connection joint cools to 300°C. At this point, the connection of the space truss members is complete.

[0071] The features described and / or illustrated above with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, and / or in combination with or in lieu of features in other embodiments.

[0072] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, components, or combinations thereof.

[0073] Many features and advantages of these embodiments are apparent from this detailed description, and therefore the appended claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. Furthermore, since many modifications and alterations will readily occur to those skilled in the art, the embodiments of the invention are not intended to be limited to the precise structures and operations illustrated and described, but rather to encompass all suitable modifications and equivalents falling within their scope.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0075] The parts of this invention not described in detail are techniques known to those skilled in the art.

Claims

1. A method for non-vacuum brazing connection of high-temperature resistant space truss members, characterized in that, The structure to be brazing connected is a space truss node and a space truss bar, the space truss node comprises a plurality of connecting pipes in different directions, each of the connecting pipes is used for being connected with a space truss bar by welding, and the brazing connection comprises the following steps: Fixing the space truss node on a tool; Applying the solder on the connecting end of the space truss node or the space truss bar, sleeving the space truss node and the space truss bar, and fixing the truss bar by using the tool; Covering a quartz isolation cover on the brazing connection part, and inputting inert protective gas; Setting a non-contact induction brazing device outside the quartz isolation cover and corresponding to the brazing connection part to perform electromagnetic induction heating; Controlling the induction heating current and heating time, completing brazing, removing the non-contact induction brazing device, continuously inputting inert protective gas in the quartz isolation cover until cooling to a removal temperature, and removing the quartz isolation cover; The space truss node and the space truss bar are made of titanium-containing materials; and the solder metal component is Ti-25Cu-10Zr-6Ni-xMo, x = 0.5-1.

5.

2. The method of claim 1, wherein, The space truss node is made of pure titanium or titanium alloy; and the space truss bar is made of a continuous SiC fiber reinforced titanium-based composite material, and the fiber volume fraction is 45%-55%.

3. The method of claim 2, wherein, The solder is in a paste form, comprising a metal component and a non-metal component, the non-metal component is terpineol, and the mass fraction of the metal component in the solder is 60%-80%.

4. The method of claim 3, wherein, The amount of the solder is 5-10 times the cavity volume of the space truss bar and the space truss node to be welded.

5. The method of claim 1, wherein, The outer diameter of the space truss bar is the same as the outer diameter of the connecting pipe of the space truss node, the inner diameter of the space truss bar is greater than the inner diameter of the connecting pipe of the space truss node, the connecting end of the connecting pipe of the space truss node is provided with a concave step, the outer diameter of the step is less than the inner diameter of the space truss bar, and the space truss bar is sleeved at the step; The difference between the outer diameter of the step and the inner diameter of the space truss bar is 0.06 mm-0.12 mm, and the length of the step is 1 / 2-1 of the outer diameter of the space truss bar.

6. The method of claim 1, wherein, The quartz isolation cover comprises two half-enclosing cover bodies, the two cover bodies are butted to enclose the brazing connection part, and the two cover bodies are non-sealingly connected; each cover body comprises an opening for respectively inputting and outputting gas.

7. The method of claim 6, wherein, The induction coil used in the non-contact induction brazing device is half-enclosing, and there are two half-enclosing induction coils which cover the brazing connection part from two sides. Alternatively, the induction coil used in the non-contact induction brazing device is planar, and there are two planar induction coils which are arranged on the outside of the brazing connection part in a parallel manner.

8. The method of claim 7, wherein, The induction coil is fixed by a support, and the support drives the induction coil to rotate around the brazing connection part; The distance between the induction coil and the space truss node is 10 mm-30 mm. During the welding process, the inductive heating current ranges from 400A to 600A, and the heating time ranges from 60s to 180s; after the welding process, the inductive heating current ranges from 100A to 200A, and the duration ranges from 10s to 20s.

9. The method of claim 7, wherein, A plurality of the spatial truss nodes are welded in parallel with spatial truss bars.

10. The method of claim 1, wherein, The inert gas is nitrogen or argon, and the gas flow is 10L / min to 15L / min; the removal temperature is 300 DEG C.

Images