High-precision and reliable connection method of pure nickel three-dimensional cooling loop structure

Abstract

According to the high-precision reliable connection method of the pure nickel three-dimensional cooling loop structure, the pure nickel three-dimensional cooling loop structure comprises a stainless steel pipe and a pure nickel cold plate, and the connection method comprises the steps that S1, high-precision pipeline forming is achieved through a multi-radius one-time bent pipe forming method; s2, the pure nickel cold plate is divided into a cover plate and a bottom plate, and a heat dissipation micro-channel is machined in the bottom plate; the method comprises the following steps: (1) putting a cover plate into a micro-channel of a bottom plate, enabling the micro-channel of the bottom plate to face downwards, and performing primary welding on a bottom plane, in contact with the micro-channel of the bottom plate, of the cover plate; (2) according to the direction that the cover plate is above and the bottom plate is below, welding seam areas between the vertical faces, in contact with the micro-channels, of the cover plate and the bottom plate are connected; when the stainless steel pipe and the pure nickel cold plate are assembled and welded, a shape follow-up tool is used for fixing the positions of the straight sections of the pure nickel cold plate and the stainless steel pipe, it is guaranteed that the relative positions are fixed before and after welding and in the welding process, and high-precision shape and position control is achieved.

Description

Technical Field

[0001] The present invention relates to a high-precision and reliable connection method for a pure nickel three-dimensional cooling circuit structure, belongs to the field of metal connection technology, relates to pure nickel, stainless steel, and the brazing connection between pure nickel and stainless steel, and particularly relates to high-precision welding and dimensional control of three-dimensional pipelines. Background Art

[0002] The three-dimensional cooling circuit is the main heat dissipation component on the satellite-borne high-power laser. The component is mainly composed of pure nickel cold plates, stainless steel pipes and corresponding seals.

[0003] In China, with the development of satellite-borne laser technology, the heat dissipation power of lasers is getting higher and higher, which puts higher requirements on the heat dissipation structure of satellite-borne lasers: the power of a single laser has increased significantly, and the traditional stainless steel heat dissipation cooling structure can no longer meet the requirements. In addition, due to the increase in on-orbit time requirements, further requirements are put forward for the reliability of long-term application of the heat dissipation structure.

[0004] Existing cooling structures made of stainless steel cold plates and stainless steel tubes are durable and highly reliable. However, the heat dissipation efficiency of stainless steel cold plates cannot meet the heat dissipation requirements of the next generation of high-power satellites. Pure nickel is corrosion-resistant, high-temperature-resistant, and oxidation-resistant, and has a high thermal conductivity (pure nickel has a thermal conductivity of approximately 82.6 W / (m·K) compared to stainless steel, which has a thermal conductivity of approximately 16.3 W / (m·K)). Therefore, pure nickel is chosen as the raw material for cold plates and cooling structures to meet the heat dissipation requirements of high-power satellites.

[0005] However, the cooling structure composed of cold plates made of pure nickel has the following difficulties:

[0006] (1) Multiple stages of welding are required to ultimately form a cooling structure, involving multiple welding steps of the overall structure and welding between dissimilar materials (nickel and stainless steel);

[0007] (2) As the requirements for dimensional accuracy of satellite radiators are further improved, high-precision pipe forming is required;

[0008] (3) Since the cooling structure is a component-level product, consisting of a stainless steel tube and a nickel cold plate in series, it is very easy to deform, and the relative positions of the components need to be kept unchanged before and after welding;

[0009] (4) The new generation of radiators has put forward further requirements on reliability and durability.

[0010] Therefore, it is necessary to develop a high-precision and reliable connection method for a pure nickel three-dimensional cooling circuit structure. Summary of the Invention

[0011] The technical problem to be solved by the present invention is: to overcome the problem of insufficient heat dissipation efficiency of the current stainless steel cooling structure, to improve the overall heat dissipation performance of the cooling structure to meet the demand for the sharp increase in laser power, and to propose a high-precision and reliable connection method for a pure nickel three-dimensional cooling loop structure.

[0012] The purpose of the present invention is achieved through the following technical solutions:

[0013] A high-precision and reliable connection method for a pure nickel three-dimensional cooling circuit structure, wherein the pure nickel three-dimensional cooling circuit structure includes a stainless steel tube and a pure nickel cold plate. The connection method includes:

[0014] S1. High-precision forming of stainless steel pipes: Use the multi-radius one-time forming pipe bending method to achieve high-precision pipe forming, ensuring that the straight section length deviation between each two bends in the pipe bending process is less than 1mm, and the bending angle deviation is less than 5°;

[0015] S2. Design of a hierarchical welding process for a three-dimensional circuit structure: The pure nickel cold plate is divided into a cover plate and a base plate, and heat dissipation micro-grooves are machined in the base plate; ① Primary welding between the planes of the cover plate and the base plate micro-grooves: The first welding is performed with the cover plate at the bottom and the base plate at the top to complete the plane weld connection of the cover plate and the base plate micro-grooves, and the plane is parallel to the entire cover plate (for example, multiple ribs can be provided in the base plate micro-grooves, and the end faces of the multiple ribs serve as the plane); ② Secondary welding between the vertical surfaces of the cover plate and the base plate micro-grooves: The second welding is performed with the cover plate at the top and the base plate at the bottom to complete the vertical weld connection of the cover plate and the base plate micro-grooves;

[0016] Assembly and welding of stainless steel pipes and pure nickel cold plates: During assembly and welding, a form-fitting fixture is used to fix the position of the pure nickel cold plate and the straight section of the stainless steel pipe, and the relative position is fixed before, after, and during welding to achieve high-precision shape and position control. After the above three-level brazing process, the welding and manufacturing of the cooling circuit structure is realized;

[0017] Reliability test method for pure nickel three-dimensional cooling circuit structure: Through XYZ three-axial random vibration test, the vibration conditions in the environment are simulated. Through positive pressure test and helium mass spectrometry detection, it is determined whether the weld and the pure nickel three-dimensional cooling circuit structure as a whole can withstand environmental vibration and whether it can meet the leakage-free use requirements under long-term pressure, thereby ensuring the reliability of the pure nickel three-dimensional cooling circuit structure and manufacturing process.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The present invention realizes high-precision manufacturing of the entire cooling structure by combining high-precision pipeline forming, graded welding process, high-precision shape and position control manufacturing process and other methods, and confirms the reliability of the overall cooling structure by simulating factors such as vibration and pressure during actual use.

[0020] (2) The present invention proposes a three-dimensional dissimilar metal cooling structure welding manufacturing method based on the structural characteristics of the three-dimensional cooling circuit composed of pure nickel and stainless steel pipes. After welding, the entire assembly can withstand 3MPa air pressure without leakage. The position deviation of the stainless steel pipe and the pure nickel cooling and the three-dimensional model is within 3mm, which fully meets the design technical requirements and successfully passes the vibration test.

[0021] (3) The process flow of the method of the present invention is simple, the welding reliability is high, the welding efficiency is high, and the product quality is stable. In the early stage, several sets of loop welding production and manufacturing have no weld quality problems, the process reliability is high, and the product quality is stable BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of a pure nickel cold plate bottom plate;

[0023] Figure 2 This is a schematic diagram of a pure nickel cold plate cover;

[0024] Figure 3 The stainless steel pipe is processed by a stable pipe bending process;

[0025] Figure 4 This is a schematic diagram of the cooling structure after the entire welding is completed. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0027] A high-precision and reliable connection method for a pure nickel three-dimensional cooling circuit structure, the pure nickel three-dimensional cooling circuit structure includes a stainless steel pipe and a pure nickel cold plate, the pure nickel cold plate includes a bottom plate and a cover plate, respectively. Figure 1 、 Figure 2 As shown; according to the drawing, the bottom plate and cover plate are processed, and micro grooves are provided on the bottom plate.

[0028] Example 1:

[0029] High-precision and reliable connection methods include:

[0030] (1) Three-dimensional pipeline forming: Purchase φ4mm, 0.5mm wall thickness stainless steel pipes, the material is 1Cr18Ni9Ti, use a special mold combined with a pipe bending machine to form the pipe. Figure 3 As shown, the pipe length and angle of each bending position and between the bending positions are tested, and the pipe length deviation between each two bending positions is required to be less than 1mm, and the angle deviation of each bending position is required to be less than 5°.

[0031] (2) Graded brazing:

[0032] Place the cover plate into the micro-grooves of the base plate with the micro-grooves facing downwards, and perform welding on the bottom plane where the cover plate and the micro-grooves of the base plate contact, with the welding temperature at 1080°C.

[0033] With the cover plate on top and the base plate on the bottom, perform the weld area connection between the vertical surfaces where the cover plate and the base plate micro-groove contact, with a welding temperature of 1060°C;

[0034] The stainless steel pipe and the pure nickel cold plate are assembled and welded. The pure nickel cold plate and the straight section of the stainless steel pipe are fixed with a form-fitting fixture to fix the relative position before, after and during welding. The welding temperature is 1035℃.

[0035] After the above three-level brazing process, the welding manufacturing of the cooling structure is realized, such as Figure 4 shown.

[0036] Reliability testing: First, an XYZ triaxial random vibration test was conducted to simulate the vibration conditions in the environment. Then, 3MPa nitrogen was filled into the pure nickel three-dimensional cooling loop structure, and the pressure drop method was used to observe whether there was any gas leakage. Finally, a helium mass spectrometer leak detector was used to test the air tightness of the pure nickel three-dimensional cooling loop structure using the helium hood method.

[0037] Implementation effect of the present invention: After the axial random vibration test, the cooling structure obtained by the above method has a pressure drop of 0.02 MPa within 30 minutes under a nitrogen pressure of 3 MPa, indicating that the cooling structure obtained by the method can meet the sealing requirements, and the product finally successfully passed the heat dissipation performance test.

[0038] Example 2:

[0039] (1) Pure nickel cold plate processing: machining stainless steel cold plate according to the drawing;

[0040] (2) High-precision pipe forming: Use a special mold combined with a pipe bending equipment to form the pipe. After forming, test the pipe length and angle at each bending position and between bending positions. The pipe length deviation between each two bending positions is required to be less than 1mm, and the angle deviation at each bending position is required to be less than 5°.

[0041] (3) Graded brazing: First, pure nickel cold plate brazing is completed at 1060℃, and then pure nickel cold plate and stainless steel tube brazing is carried out at 1035℃ to ensure that the weld appearance is full and uniform fillet is formed;

[0042] (4) Airtightness test: Through 4MPa nitrogen positive pressure and helium mass spectrometry negative pressure test, it is confirmed that the cooling structure is sealed effectively and meets the operating conditions.

[0043] Implementation effect: The cooling structure obtained by the above method has a pressure drop of 0.02MPa within 30 minutes under an internal pressure of 3MPa, indicating that the cooling structure obtained by this method can meet the sealing requirements and pass the heat dissipation performance test.

[0044] This process method has stable brazing quality. Up to now, the welding success rate has been 100%, with high reliability and high production efficiency.

[0045] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

[0046] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solutions of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A high-precision and reliable connection method for a pure nickel three-dimensional cooling circuit structure, characterized in that: The pure nickel three-dimensional cooling circuit structure includes stainless steel pipes and pure nickel cold plates. The connection methods include: S1. Use the multi-radius one-time bending method to achieve high-precision pipe forming; S2. Separate the pure nickel cold plate into a cover plate and a base plate, and machine heat dissipation micro-grooves in the base plate. ① Place the cover plate into the micro-grooves of the base plate, with the micro-grooves facing downward, and perform the first weld on the bottom plane where the cover plate and the base plate contact the micro-grooves. ② With the cover plate on top and the base plate on the bottom, weld the vertical areas where the cover plate and the base plate contact the micro-grooves. When assembling and welding the stainless steel tube and the pure nickel cold plate, a form-fitting fixture is used to fix the position of the pure nickel cold plate and the straight section of the stainless steel tube to ensure the relative position before, after and during welding, and achieve high-precision shape and position control.

2. The high-precision and reliable connection method according to claim 1, characterized in that: In S1, ensure that the straight line length deviation between each two bends in the pipeline bending process is less than 1mm, and the bending angle deviation is less than 5°.

3. The high-precision and reliable connection method according to claim 1, characterized in that: After S2, an XYZ triaxial random vibration test was conducted to simulate the vibration conditions in the environment. Positive pressure testing and helium mass spectrometry were conducted to determine whether the welds and the overall structure of the pure nickel three-dimensional cooling circuit could withstand the environmental vibration and whether they could meet the leakage-free use requirements under long-term pressure, thereby ensuring the reliability of the pure nickel three-dimensional cooling circuit structure and manufacturing process.

4. The high-precision and reliable connection method according to claim 1, characterized in that: The pure nickel three-dimensional cooling circuit structure can withstand 3MPa air pressure without leakage.

5. The high-precision and reliable connection method according to claim 1, characterized in that: The temperatures of the three welding processes are 1080℃, 1060℃ and 1035℃ respectively.

6. A pure nickel three-dimensional cooling circuit structure, characterized in that: It is made by the high-precision and reliable connection method described in claim 1.

7. The pure nickel three-dimensional cooling circuit structure according to claim 6, characterized in that: The stainless steel pipe is φ4mm, 0.5mm wall thickness, and the material is 1Cr18Ni9Ti.

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