A water distribution manifold and method of making the same

Abstract

This invention belongs to the field of additive manufacturing, specifically disclosing a water distribution manifold and its preparation method. The water distribution manifold includes a main pipe body and at least two branch nozzles disposed on the main pipe body; the main pipe body and the branch nozzles are integrally connected; the leakage rate of the water distribution manifold during helium mass spectrometry leak detection is less than 1×10⁻⁶. ‑9 Pa·m 3 / s; the tensile strength at the connection between the main pipe body and the branch nozzle is >450MPa; the branch nozzle contains equiaxed crystals. This invention uses a laser selective melting metal 3D printing method to print the interface layer and the branch nozzle body layer by layer on the main pipe body, forming an integrated interface between the branch nozzle body and the main pipe body. This significantly improves the structural reliability, interface mechanical properties, sealing performance, and fluid performance of the water distribution manifold.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, specifically relating to a water distribution manifold and its preparation method. Background Technology

[0002] With the rapid development of cloud computing, artificial intelligence, and high-performance computing, the power density of data centers is constantly increasing, and liquid cooling technology has become the mainstream solution for cooling high-power-density servers. In liquid-cooled server racks, the water distribution manifold is the core component for achieving efficient distribution and collection of coolant, and its performance directly determines the heat dissipation efficiency, reliability, and energy consumption level of the entire liquid cooling system.

[0003] In the field of liquid-cooled server racks, the manufacturing of water manifolds has long relied on a traditional method combining machining and brazing. This method first involves machining multiple independent metal parts, such as the main pipe, branch outlets, and return interfaces, using casting, extrusion, or CNC machine tools. These parts are then assembled and positioned using precision tooling fixtures, and brazing filler metal is applied to their joints. Finally, the entire assembly is heated in a controlled atmosphere brazing furnace, causing the brazing filler metal, with a melting point lower than the base metal, to melt and fill the joint gaps through capillary action. After cooling and solidification, a metallurgical connection is formed, thus assembling all the parts into a complete water manifold assembly.

[0004] Traditional brazing-based manufacturing methods essentially use a metal material with a melting point lower than that of the base metal (brazing filler metal) as a "bonding agent" to physically connect pre-fabricated independent components (such as main pipes and branch outlets). This fundamental principle determines that it has a series of intractable defects in high-performance liquid cooling applications.

[0005] First, there are inherent defects in the fundamental properties of the joint interface. The performance of brazed joints largely depends on the wetting ability of the filler metal on the base material, capillary action, and the limited alloying diffusion between the two. This results in a fundamental difference between the microstructure of the joint zone and the base material, and its strength, toughness, and fatigue resistance naturally constitute a "performance depression" in the entire component. Under long-term pressure cycling and fluid vibration loads, cracks are highly likely to initiate and propagate preferentially from this metallurgically weak zone.

[0006] Secondly, achieving a perfect seal presents a significant challenge. The sealing effect of brazing relies on the complete filling of complex assembly gaps by the brazing filler metal. Any slight oxidation, contamination, or assembly error can lead to the formation of microchannels, becoming a potential source of leakage. This sealing method, which relies on "filling" rather than "body forming," struggles to achieve the reliability and consistency required for critical application scenarios with extremely high leakage rate requirements.

[0007] Furthermore, the complexity and uncertainty of the process remain high. To ensure successful solder filling, extremely precise consistency control must be exercised over the assembly gaps of dozens or even hundreds of branch interfaces, which brings enormous assembly challenges and time costs. In addition, the chemical cleaning methods widely used to remove the post-soldering oxide layer generate waste liquids that require special treatment, increasing environmental compliance costs and governance burdens.

[0008] Finally, controlling the thermal deformation of the overall structure is another challenging issue. The brazing process requires localized or overall heating of the entire component. The thermal expansion incompatibility between different parts due to differences in thickness and structure can introduce residual stress and macroscopic deformation that are difficult to completely eliminate. This deformation not only affects the dimensional accuracy of the product but also often requires additional straightening processes to correct, leading to increased costs and decreased efficiency. Summary of the Invention

[0009] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide a water distribution manifold.

[0010] The second objective of this invention is to provide a method for preparing a water distribution manifold.

[0011] A third objective of this invention is to provide the application of the above-mentioned water distribution manifold or the method for preparing the above-mentioned water distribution manifold in the fields of liquid cooling systems or servers.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A first aspect of the present invention provides a water distribution manifold, comprising a pipe body and at least two branch nozzles disposed on the pipe body; the pipe body is in communication with the branch nozzles; the pipe body and the branch nozzles are integrally formed and connected. The leakage rate of the water distribution manifold during helium mass spectrometry leak detection was less than 1×10⁻⁶. -9 Pa·m 3 / s; The tensile strength at the connection between the main pipe body and the branch nozzle is >450MPa; The branch nozzle contains equiaxed crystals.

[0013] In some embodiments of the present invention, the average grain size of the equiaxed crystals is ≤5μm; in some embodiments of the present invention, the average grain size of the equiaxed crystals is ≤4μm; in some embodiments of the present invention, the average grain size of the equiaxed crystals is ≤3μm.

[0014] In some embodiments of the present invention, the average grain size of the equiaxed crystals is 0.1-5 μm; in some embodiments of the present invention, the average grain size of the equiaxed crystals is any value or a range formed by any two of 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, and 5 μm.

[0015] In some embodiments of the present invention, the ratio between the transverse dimension and the longitudinal dimension of the equiaxed crystal is 1:(0.5-5); in some embodiments of the present invention, the ratio between the transverse dimension and the longitudinal dimension of the equiaxed crystal is any value of 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5 or a range of any two of these values.

[0016] In this invention, the lateral dimension refers to the dimension along the direction parallel to the central axis of the pipe body; the longitudinal dimension refers to the dimension along the direction perpendicular to the central axis of the pipe body, that is, the dimension along the central axis of the branch nozzle body.

[0017] In some embodiments of the present invention, the density of the branch nozzle is ≥99.7%. The density is tested using the Archimedes displacement method.

[0018] In some embodiments of the present invention, the branch nozzle is manufactured using a laser selective melting metal 3D printing method; in some embodiments of the present invention, when the branch nozzle is printed using a laser selective melting metal 3D printing method, there is an overlapping and interlocking structure in the molten pool between different printing layers.

[0019] In some embodiments of the present invention, the material of the water distribution manifold is selected from stainless steel or titanium alloy.

[0020] In some embodiments of the present invention, the material of the branch nozzle is selected from stainless steel or titanium alloy.

[0021] In some embodiments of the present invention, the manifold and the branch nozzle are made of the same material.

[0022] In some embodiments of the present invention, the branch nozzle includes a branch nozzle body and an interface layer; the branch nozzle body is integrally connected to the pipe body through the interface layer. In this invention, integral connection means that there are no obvious connection marks at the connection location, i.e., no obvious weld seam.

[0023] In some embodiments of the present invention, the interface layer contains equiaxed grains, and the refined equiaxed grains can improve tensile strength by “grain boundaries hindering dislocation movement”. In some embodiments of the present invention, the interface layer includes a first printed layer, a second printed layer, and a third printed layer stacked sequentially; the first printed layer is located on the pipe body. The first printed layer refers to the first layer printed on the surface of the pipe body using a laser selective melting metal 3D printing method; the second printed layer refers to the second layer printed on the surface of the pipe body using a laser selective melting metal 3D printing method; and the third printed layer refers to the third layer printed on the surface of the pipe body using a laser selective melting metal 3D printing method.

[0024] In some embodiments of the present invention, the ratio between the lateral dimension and the longitudinal dimension of the equiaxed crystal in the first printing layer is 1:(0.5-1.5); in some embodiments of the present invention, the ratio between the lateral dimension and the longitudinal dimension of the equiaxed crystal in the first printing layer is any value of 1:0.5, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.49, 1:1.5 or a range formed by any two of these values.

[0025] In some embodiments of the present invention, the ratio between the lateral dimension and the longitudinal dimension of the equiaxed crystal in the second printing layer is 1:(1.5-5); in some embodiments of the present invention, the ratio between the lateral dimension and the longitudinal dimension of the equiaxed crystal in the second printing layer is any value or a range formed by any two of the following: 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.2, 1:3.5, 1:3.8, 1:4, 1:4.2, 1:4.5, 1:4.8, 1:5.

[0026] In some embodiments of the present invention, the ratio between the lateral and longitudinal dimensions of the equiaxed crystal in the third printing layer is 1:(1.5-5); in some embodiments of the present invention, the ratio between the lateral and longitudinal dimensions of the equiaxed crystal in the third printing layer is any value or a range formed by any two of the following: 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.2, 1:3.5, 1:3.8, 1:4, 1:4.2, 1:4.5, 1:4.8, 1:5.

[0027] In the water distribution manifold of this invention, during the selective laser melting (SLM) 3D printing process, due to the low thermal conductivity of the surrounding powder, heat is mainly conducted through the lower layers ("lower" refers to the direction closer to the main body of the pipe, and "upper" refers to the direction farther from the main body of the pipe). As the number of printed layers increases, the heat conduction path lengthens, leading to an increase in the upper layer temperature, a larger molten pool size, and a larger grain size. Therefore, compared with the first printed layer, the ratio between the lateral and longitudinal dimensions of isometric crystals in the second and third printed layers increases. During SLM printing, the thermal conductivity of the metal powder is much lower than that of the solid substrate, and the heat from the molten pool is mainly conducted to the lower, solidified components. As the number of printed layers increases, the downward heat conduction path becomes longer, reducing the heat dissipation efficiency of the molten pool and increasing the high-temperature retention time of the molten pool, which can easily cause the upper layer grains to grow. This invention reduces the laser power and increases the scanning speed layer by layer to counteract the heat accumulation effect of the upper layer, so that the bottom layer (first printed layer) forms near-equiaxed crystals with an aspect ratio of 1:(0.5-1.5), and the upper layers gradually transition to slender oriented grains with an aspect ratio of 1:(1.5-5), achieving a smooth transition between layers, effectively reducing residual stress at the interface, and significantly improving the bonding strength and pressure fatigue resistance of the pipe connection interface.

[0028] In some embodiments of the present invention, the tensile strength at the connection between the pipe body and the branch nozzle is >480MPa; in some embodiments of the present invention, the tensile strength at the connection between the pipe body and the branch nozzle is 480~550MPa; in some embodiments of the present invention, the tensile strength at the connection between the pipe body and the branch nozzle is 480~540MPa.

[0029] In some embodiments of the present invention, the shear strength at the connection between the pipe body and the branch nozzle is >350MPa; in some embodiments of the present invention, the shear strength at the connection between the pipe body and the branch nozzle is 370~450MPa; in some embodiments of the present invention, the shear strength at the connection between the pipe body and the branch nozzle is 370~420MPa.

[0030] In some embodiments of the present invention, the density at the connection between the pipe body and the branch nozzle is ≥99.65%; in some embodiments of the present invention, the density at the connection between the pipe body and the branch nozzle is 99.65~99.9%.

[0031] In some embodiments of the present invention, the flow rate difference between at least two of the branch nozzles is ≤3.5%; in some embodiments of the present invention, the flow rate difference between at least two of the branch nozzles is 1% to 3.5%; in some embodiments of the present invention, the flow rate difference between at least two of the branch nozzles is 2% to 3%.

[0032] In some embodiments of the present invention, the water distribution manifold is at 10 6 During the pressure cycle test, the number of leaks at the branch nozzles was 0.

[0033] In some embodiments of the present invention, the deformation of the surface of the pipe body is ≤0.15 mm / m; in some embodiments of the present invention, the deformation of the surface of the pipe body is ≤0.13 mm / m.

[0034] The second aspect of the present invention provides a method for preparing the water distribution manifold described in the first aspect of the present invention, comprising the following steps: An interface layer is printed on the main body of the pipe using the selective laser melting metal 3D printing method. Then, the branch nozzle body is printed on the interface layer using the selective laser melting metal 3D printing method. After heat treatment, the water distribution manifold is obtained. The surface roughness (i.e., Ra) of the main body of the pipe is 4~6μm; The laser power during the printing of the interface layer is greater than the laser power during the printing of the branch nozzle body.

[0035] This invention employs a separate printing strategy for the interface layer and the branch nozzle body. Through differentiated laser energy input, it ensures micro-melting of the pipe body surface and the formation of a dense metallurgical bonding zone with the cladding powder, achieving an interface strength exceeding 95% of the pipe body's base material. The invention uses a laser selective melting metal 3D printing method to sequentially print the interface layer and the branch nozzle body on the pipe body surface. A high-energy laser melts the branch nozzle preparation material (i.e., metal powder) together with the pipe body surface layer, forming a metallurgical bonding zone with a continuous transition from the base material to the newly added structural components and microstructure. In the region of the metallurgical bonding zone near the branch nozzle, due to the extremely rapid cooling rate, fine equiaxed crystals typically appear, eliminating the heterogeneous interface that is a potential failure source. This fundamentally eliminates the weak connection interface of traditional brazing, improving the interface strength and sealing performance of the branch manifold.

[0036] This invention uses a laser selective melting metal 3D printing method to print branch nozzles. During printing, the rapid solidification of the small molten pool can reduce defects such as porosity and looseness, ensuring the high density (≥99.7%) of the branch nozzles.

[0037] In some embodiments of the present invention, the interior of the branch nozzle body is provided with a flow channel, which is designed with fully optimized fluid dynamics to improve the fluid performance of the water distribution manifold.

[0038] In some embodiments of the present invention, the printing refers to the process of melting metal powder with a laser and then solidifying it layer by layer at the printing location on the surface of the pipe body to form an interface layer and a branch nozzle body.

[0039] In some embodiments of the present invention, the surface roughness (i.e., Ra) of the pipe body is any value of 4μm, 4.5μm, 5μm, 5.5μm, 6μm or a range formed by any two of them.

[0040] In some embodiments of the present invention, the laser power of the interface layer during printing is 10-60W greater than the laser power of the branch nozzle body during printing; in some embodiments of the present invention, the difference between the laser power of the interface layer during printing and the laser power of the branch nozzle body during printing is any value of 10W, 20W, 30W, 40W, 50W, 60W, or a range formed by any two of these values. When the difference in laser power is within the range defined by the present invention, micro-melting occurs on the surface of the pipe body. At this time, on the one hand, the thermal deformation of the pipe body is small, and on the other hand, the bonding strength and sealing performance of the resulting water distribution manifold are significantly improved.

[0041] In some embodiments of the present invention, the number of printed layers of the interface layer is 1 to 5; in some embodiments of the present invention, the number of printed layers of the interface layer is any value of 1, 2, 3, 4, or 5, or a range formed by any two of them.

[0042] In some embodiments of the present invention, the laser power during interface layer printing is 360~420W; in some embodiments of the present invention, the laser power during interface layer printing is any value of 360W, 370W, 380W, 390W, 400W, 410W, 420W or a range formed by any two of them.

[0043] In some embodiments of the present invention, the scanning speed during the printing of the interface layer is 700~1000mm / s; in some embodiments of the present invention, the scanning speed during the printing of the interface layer is any value of 700mm / s, 750mm / s, 800mm / s, 850mm / s, 900mm / s, 950mm / s, 1000mm / s or a range formed by any two of them.

[0044] In some embodiments of the present invention, the laser power during the printing of the interface layer is 380-400W and the scanning speed is 750-850mm / s, so that the surface of the branch nozzle body and the pipe body melt together to form a continuous transition metallurgical bonding zone.

[0045] In some embodiments of the present invention, the scanning pitch during the printing of the interface layer is 80~110μm; in some embodiments of the present invention, the scanning pitch during the printing of the interface layer is any value of 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm or a range formed by any two of them.

[0046] In some embodiments of the present invention, the thickness of each interface layer during printing is 20-50 μm; in some embodiments of the present invention, the thickness of each interface layer during printing is any value of 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or a range formed by any two of these values.

[0047] In some embodiments of the present invention, the scanning strategy during interface layer printing is partition jumping and / or interlayer rotation scanning. In some embodiments of the present invention, the scanning strategy during interface layer printing is partition jumping and 67° interlayer rotation scanning.

[0048] In some embodiments of the present invention, the interface layer is printed using gradient printing. When printing the first layer, the laser power is 410-420W and the scanning speed is 650-750mm / s. High energy is used during the printing of the first layer to ensure micro-melting of the pipe body, forming an integrated microscopic interface between the pipe body and the interface layer. When printing the second and third layers, the laser power is 370-390W and the scanning speed is 800-900mm / s. Higher energy is used for the transition between the second and third layers. When printing the fourth and fifth layers, the laser power is 360-370W and the scanning speed is 900-1000mm / s. Lower laser power during the printing of the fourth and fifth layers further alleviates thermal stress during printing. When gradient printing is used, the interface layer bondes better with the pipe body and the branch nozzle body after printing. Gradient printing can eliminate abrupt interface changes, form a stress-relieving gradient, suppress interface porosity, achieve dense bonding, optimize crystal orientation, and enhance interface bonding strength.

[0049] In some embodiments of the present invention, the thickness of each layer during interface layer printing is 30~40μm, and a thinner layer thickness is used to improve the bonding quality.

[0050] In some embodiments of the present invention, the laser power during printing of the branch nozzle body is 340~370W; in some embodiments of the present invention, the laser power during printing of the branch nozzle body is any value of 340W, 345W, 350W, 355W, 360W, 365W, 370W or a range formed by any two of them.

[0051] In some embodiments of the present invention, the scanning speed during printing of the branch nozzle body is 1000~1500 mm / s; in some embodiments of the present invention, the scanning speed during printing of the branch nozzle body is any value of 1000 mm / s, 1100 mm / s, 1200 mm / s, 1300 mm / s, 1400 mm / s, 1500 mm / s, or a range formed by any two of them.

[0052] In some embodiments of the present invention, the scanning spacing during printing of the branch nozzle body is 100~130μm; in some embodiments of the present invention, the scanning spacing during printing of the branch nozzle body is any value of 100μm, 105μm, 110μm, 115μm, 120μm, 125μm, 130μm or a range formed by any two of them.

[0053] In some embodiments of the present invention, the printing thickness of each layer during the printing of the branch nozzle body is 20-50 μm; in some embodiments of the present invention, the printing thickness of each layer during the printing of the branch nozzle body is any value selected from 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, and 50 μm, or a range formed by any two of these values. In some embodiments of the present invention, the printing layer thickness of each layer during the printing of the branch nozzle body is 30-40 μm to improve efficiency.

[0054] In some embodiments of the present invention, the scanning strategy during printing the branch nozzle body is partition jumping and / or interlayer rotation scanning. In some embodiments of the present invention, the scanning strategy during printing the branch nozzle body is partition jumping and 67° interlayer rotation scanning.

[0055] This invention employs a partitioned scanning method and a 67° interlayer rotation scanning technique to scan both the interface layer and the branch nozzle body during printing. This effectively manages heat accumulation and controls thermal deformation during printing to within 0.1 mm / m. Unlike the overall heating of traditional brazing and the continuous heat input of overall 3D printing, this invention achieves effective management of thermal stress during manufacturing through a partitioned scanning strategy and interlayer cooling control.

[0056] In some embodiments of the present invention, the thermal deformation of the water distribution manifold during the printing process is ≤0.1mm / m. The present invention controls the thermal deformation during the printing process to within 0.1mm / m by effectively managing heat accumulation.

[0057] In some embodiments of the present invention, an annular protective gas is provided around the laser processing point during printing, which can reduce the oxygen content around the laser printing point to below 50 ppm.

[0058] In some embodiments of the present invention, the laser selective melting metal 3D printing method is performed under a protective atmosphere. In some embodiments of the present invention, the laser selective melting metal 3D printing method is performed under a protective atmosphere with an oxygen content of less than 100 ppm. In some embodiments of the present invention, the laser selective melting metal 3D printing method is performed under a protective atmosphere with an oxygen content of less than 50 ppm.

[0059] In some embodiments of the present invention, the protective atmosphere is selected from at least one gas selected from nitrogen, argon, and helium.

[0060] In some embodiments of the present invention, the material of the metal powder used in the laser selective melting metal 3D printing method is the same as the material of the pipe body.

[0061] In some embodiments of the present invention, the wall thickness of the interface layer is 2-3 mm.

[0062] In some embodiments of the present invention, the wall thickness of the branch nozzle body is 1~2mm.

[0063] In some embodiments of the present invention, the wall thickness gradually decreases from the bottom of the interface layer (i.e., the area where the interface layer contacts the pipe body) to the end of the branch nozzle body (i.e., the side of the branch nozzle body away from the pipe body). This special design achieves lightweighting while ensuring connection strength.

[0064] In some embodiments of the present invention, two to three adjacent branch nozzles are connected to the main body of the pipe through a common base, reducing the number of individual interfaces and making it suitable for high-density layouts.

[0065] In some embodiments of the present invention, the metal powder is stainless steel or titanium alloy.

[0066] In some embodiments of the present invention, the material of the pipe body is stainless steel or titanium alloy.

[0067] In some embodiments of the present invention, the stainless steel is selected from 304 stainless steel and 316 stainless steel.

[0068] In some embodiments of the present invention, the metal powder is 316L ultra-low carbon powder, and the main body of the pipe is a conventional 316 stainless steel pipe, which controls costs and ensures the corrosion resistance of the grafting area.

[0069] In some embodiments of the present invention, the pipe body is made of austenitic stainless steel 304, and the metal powder is duplex stainless steel 2205 powder. The rapid solidification characteristics of additive manufacturing are utilized to create a gradient transition structure, balancing strength and corrosion resistance.

[0070] In some embodiments of the present invention, the metal powder is 1-3% nano-Cu or Ag powder mixed into 316L base powder. After printing, appropriate heat treatment is performed to enrich Cu / Ag elements at the grain boundaries, giving the material certain antibacterial properties, making it suitable for special water quality environments.

[0071] In some embodiments of the present invention, for ultra-large water distribution manifolds, a 6-axis robot holding a laser head and a powder feeder can be used to perform grafting printing on a fixed large pipe body, breaking through the limitations of equipment forming space.

[0072] In some embodiments of the present invention, additive and subtractive composite manufacturing equipment using an integrated machining center is employed to perform end face finishing immediately after printing the branch nozzle, thereby achieving one-stop completion of "printing-processing".

[0073] In some embodiments of the present invention, the pipe body is surface treated before use to make the surface roughness of the pipe body 4~6μm.

[0074] In some embodiments of the present invention, the pipe body is sandblasted before use to make the surface roughness of the pipe body 4~6μm; the sandblasting treatment in the present invention is to form an activation layer of rough surface with a roughness of 4~6μm on the surface of the pipe body, so as to provide an interface basis for subsequent metallurgical bonding.

[0075] In some embodiments of the present invention, the pipe body is surface treated by chemical etching before use, so that the surface roughness of the pipe body is 4~6μm.

[0076] In some embodiments of the present invention, the chemical etching refers to selectively etching the pipe body using a chemical solvent, controlling the etching depth to be 10~50μm, thereby making the surface roughness of the pipe body 4~6μm.

[0077] In some embodiments of the present invention, the chemical solvent contains ferric chloride and / or nitric acid.

[0078] In some embodiments of the present invention, the surface of the pipe body is processed using a nanosecond laser or picosecond laser before use, resulting in a surface roughness of 4-6 μm. In some embodiments of the present invention, microstructure patterns, such as a square array of micro-pits (50-100 μm in diameter, 20-40 μm in depth, and 100-200 μm in spacing), are processed on the surface of the pipe body using a nanosecond laser or picosecond laser before use. This regularized microstructure facilitates molten pool anchoring and improves repeatability.

[0079] In some embodiments of the present invention, the pipe body is first sandblasted before use, and then chemically etched to achieve a surface roughness of 4-6 μm. Mechanical sandblasting is first used to create a rough surface on the pipe body, followed by chemical etching, such as dilute nitric acid treatment, to further increase the surface energy on top of the roughening, thus promoting the wetting of laser powder during laser printing.

[0080] In some embodiments of the present invention, the temperature of the heat treatment is 800~1100℃; in some embodiments of the present invention, the temperature of the heat treatment is any value of 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃ or a range formed by any two of them.

[0081] In some embodiments of the present invention, the heat treatment time is 1 to 6 hours; in some embodiments of the present invention, the heat treatment time is any value of 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, or a range formed by any two of them.

[0082] In some embodiments of the present invention, the heat treatment step is as follows: heat treatment at 800~1100℃ for 1~6 hours, followed by furnace cooling to eliminate printing internal stress.

[0083] In some embodiments of the present invention, the heat treatment steps are as follows: first, holding at 350~450℃ for 1.5~2.5h to eliminate more than 80% of the printing stress; then, holding at 600~700℃ for 1.5~2.5h to promote carbide homogenization; and finally, holding at 1000~1100℃ for 0.5~1.5h to achieve complete recrystallization. This segmented heat treatment process facilitates precise control of the microstructure and properties.

[0084] In some embodiments of the present invention, the preparation method further includes a hot isostatic pressing step, wherein the hot isostatic pressing step is performed after the heat treatment step; In some embodiments of the present invention, the temperature of the hot isostatic pressing treatment is 1000~1100℃; in some embodiments of the present invention, the temperature of the hot isostatic pressing treatment is any value of 1000℃, 1020℃, 1040℃, 1050℃, 1060℃, 1080℃, 1100℃ or a range formed by any two of them.

[0085] In some embodiments of the present invention, the pressure of the hot isostatic pressing is 90~110MPa; in some embodiments of the present invention, the pressure of the hot isostatic pressing is any value of 90MPa, 95MPa, 100MPa, 105MPa, 110MPa or a range formed by any two of them.

[0086] In some embodiments of the present invention, the hot isostatic pressing treatment time is 2 to 6 hours; in some embodiments of the present invention, the hot isostatic pressing treatment time is any value of 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, or a range formed by any two of them.

[0087] This invention employs hot isostatic pressing after heat treatment of the branch manifold, which can further improve the density of the branch manifold, achieving a density of over 99.8%, thus ensuring long-term reliability.

[0088] In some embodiments of the present invention, the preparation method further includes a finishing step, which is performed after the heat treatment step or after the hot isostatic pressing step. The present invention ensures a flatness of ≤0.05mm by finishing the sealing groove on the branch nozzle end face.

[0089] In some embodiments of the present invention, the prepared water distribution manifold can be first magnetically polished to remove the adhesive powder, and then electrolytically polished to obtain a mirror effect.

[0090] In some embodiments of the present invention, a 10-20 μm thick polytetrafluoroethylene (PTFE) or DLC (Diamond-like Carbon) coating is provided on the inner wall of the flow channel inside the branch nozzle body to reduce flow resistance and prevent corrosion.

[0091] The third aspect of the present invention provides the application of the water distribution manifold described in the first aspect of the present invention or the method for preparing the water distribution manifold described in the second aspect of the present invention in the field of liquid cooling systems or servers.

[0092] The beneficial effects of this invention are as follows: This invention uses a laser selective melting metal 3D printing method to print the interface layer and the branch nozzle body layer by layer on the main body of the pipe. The branch nozzle body and the main body of the pipe form an integrated interface, which can significantly improve the structural reliability, mechanical properties of the interface, sealing performance and fluid performance of the water distribution manifold. It can meet the usage requirements of servers or liquid cooling systems with extremely high requirements for sealing performance and service life.

[0093] The water distribution manifold in this invention has a small top deformation (≤0.12mm / m), a branch nozzle position error within 0.15mm, and a helium mass spectrometry leak detection rate <8×10⁻⁶. -10 Pa·m 3 / s, can be accessed via 10 6 After passing the pressure cycle test, it exhibits excellent sealing performance, with a tensile strength of ≥480MPa and a shear strength of ≥370MPa at the grafting interface. The branch flow instability is within ±3.5%, and it has superior dimensional accuracy, mechanical properties, sealing performance, and fluid performance.

[0094] Furthermore, this invention uses a laser selective melting metal 3D printing method to form a branch nozzle structure on the pipe body, which reduces material usage and significantly lowers production costs compared to traditional brazing processes. Attached Figure Description

[0095] Figure 1 This is a schematic diagram of the overall structure and partial cross-section of the water distribution manifold in Example 1.

[0096] Figure 2 This is a metallographic image of the interface layer in Comparative Example 1.

[0097] Figure 3 This is a metallographic image of the interface layer in Comparative Example 2.

[0098] Figure 4 This is a metallographic image of the interface layer in Example 1.

[0099] Figure 5 The image shows the metallographic pattern of the superimposed molten pool during printing, as shown in Example 4.

[0100] Figure 6 The image shows the microstructure of different printing layers during printing using the preparation method in Example 4. Detailed Implementation The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art by referring to the prior art. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0101] This invention utilizes a laser selective melting metal 3D printing method, using metal powder as raw material and based on a three-dimensional digital model, to print the entire water distribution manifold, including all its internal flow channels and external interfaces, in a single, integral process. Theoretically, this avoids subsequent assembly and welding processes. Specifically, an interface layer is first printed on the main pipe body, followed by the branch nozzle body. Since the branch nozzle and the main pipe body are integrally fused and grown, the internal flow channels of the branch nozzle are essentially a complete cavity without mechanical connection interfaces. This achieves a shift from "leak prevention" to "structure with no possibility of leakage." Furthermore, compared to traditional brazing processes, the manufacturing method of this invention is greatly simplified. It compresses multiple independent "machining-assembly-brazing-cleaning" sub-processes into a highly digitized "positioning-printing" process, significantly reducing reliance on manual skills and process variables, and reducing contaminant generation at the source. During the manufacturing process, this invention optimizes the printing path and applies dynamic constraints to key areas, enabling real-time offsetting and redistribution of thermal stress generated during printing, thereby achieving precise control over structural deformation and ensuring manufacturing accuracy.

[0102] Example 1 This example provides a water distribution manifold, the three-dimensional structural diagram of which is shown below. Figure 1 As shown in c, the main view is as follows Figure 1 As shown in b, the top view is as follows: Figure 1As shown in a1, the cross-sectional view along line AA in figure a1 is as follows. Figure 1 As shown in a2, the water distribution manifold is formed by a main pipe body (i.e., a 316L stainless steel square pipe) and 24 branch nozzles installed on the main pipe body, with the branch nozzles connected to the main pipe body.

[0103] When the water distribution manifold of this invention is used in a liquid-cooled server rack, the coolant will flow into the 24 branch nozzles through the main pipe body, or the coolant will collect from the 24 branch nozzles into the main pipe body.

[0104] The main body of the pipe is a 316L stainless steel square tube; the branch nozzles are formed by integrally printing 316L stainless steel powder onto the outer wall of the main pipe body using a metal additive manufacturing technology (in this example, an M450 SLM device) through laser melting. Each branch nozzle has an internal flow channel structure that connects to the main water channel inside the main pipe body.

[0105] This example provides a method for preparing a water distribution manifold, specifically including the following steps: 1. Base material: 316L stainless steel square tube conforming to ASTM A269 standard (cross-section dimensions: 50 mm × 50 mm, wall thickness: 2.5 mm, length: 800 mm); 2. Powder: Conventional gas-atomized 316L stainless steel powder (particle size 15-53μm) 3. Pre-processing before printing: (1) Substrate treatment The area on the outer wall of the square tube where 24 branch nozzles are planned to be printed is sandblasted using 120-mesh white corundum to achieve a surface roughness Ra of 5.0-6.0 μm. It is then ultrasonically cleaned with alcohol and dried.

[0106] (2) 3D modeling and precise positioning The digital model of the branch nozzle is precisely registered with the scanned model of the main pipe body in the software, and the positioning accuracy is controlled within ±0.05mm.

[0107] 4. Grafting-type selective laser melting printing (i.e., selective laser melting metal 3D printing): The main body of the pipe is fixed inside the molding chamber of the M450 SLM equipment, and the protective atmosphere is high-purity argon (oxygen content <100ppm), thus enabling printing under an inert atmosphere.

[0108] The core process parameters are as follows: Interface layer printing process (layers 1-5): laser power 380W, scanning speed 800mm / s, printing thickness of each layer 30μm, scanning spacing 90μm, to ensure micro-melting of the pipe body surface and form a dense metallurgical bonding zone.

[0109] Branch nozzle body printing process (6th layer and above): laser power 350W, scanning speed 1200mm / s, printing thickness of each layer is 30μm, scanning spacing is 110μm.

[0110] Scanning strategy: Employing a 67° interlayer rotation scanning and an 8mm×8mm checkerboard partitioning strategy, heat accumulation is effectively managed, and thermal deformation during the printing process is controlled within 0.1mm / m.

[0111] 5. Post-printing heat treatment process: Stress annealing: After printing, the furnace is kept at 900℃ for 2 hours and then cooled to eliminate the internal stress of printing.

[0112] Hot isostatic pressing: The product is treated at 1100℃ and 100MPa for 4 hours to achieve an overall density of over 99.8%.

[0113] Finishing: Remove the support structure and finish the sealing groove on the end face of the branch nozzle to ensure flatness ≤0.05mm.

[0114] In this example, additive manufacturing creates a metallurgical bonding zone at the interface between the branch nozzle and the main pipe body. The microstructure of this zone is continuous and dense, with a tensile strength of not less than 400 MPa and a fatigue life that is more than five times that of a joint formed by traditional brazing, thus fundamentally eliminating the weak link of the brazed joint.

[0115] Example 2 Based on Example 1, this example enhances the interface bonding quality for operating conditions with higher pressure cyclic loads.

[0116] This example provides a method for preparing a water distribution manifold, specifically including the following steps: 1. Substrate: 316L stainless steel square tube, the same as in Example 1; 2. Powder: The same 316L stainless steel powder as in Example 1; 3. Pre-processing before printing: The pre-processing method is exactly the same as in Example 1.

[0117] 4. Graft-type selective laser melting printing: This step differs from Example 1 only in that: Interface layer printing process (layers 1-5): laser power 400W, scanning speed 750mm / s, layer thickness 30μm, scanning spacing 85μm. (Energy input is appropriately increased compared to Example 1) Branch nozzle body printing process (6th layer and above): Printing parameters are the same as in Example 1.

[0118] Scanning strategy: Same as in Example 1.

[0119] 5. Post-processing: exactly the same as in Example 1.

[0120] Example 3 This example demonstrates how the process was optimized while ensuring the water distribution manifold meets core performance requirements, aiming to improve manufacturing efficiency and reduce production costs.

[0121] This example provides a method for preparing a water distribution manifold, specifically including the following steps: 1. Substrate: 316L stainless steel square tube, the same as in Example 1; 2. Powder: The same 316L stainless steel powder as in Example 1; 3. Pre-processing before printing: The pre-processing method is exactly the same as in Example 1.

[0122] 4. Graft-type selective laser melting printing: This step differs from Example 1 only in that: The equipment and atmosphere conditions are the same as in Example 1, but the following parameters are adjusted to improve printing efficiency: Interface layer process (layers 1-3): Laser power 370W, scanning speed 850mm / s, layer thickness 40μm, scanning spacing 100μm. (Increase layer thickness appropriately to improve scanning speed) Branch nozzle body printing process (4th layer and above): laser power 350W, scanning speed 1400mm / s, printing thickness of each layer 40μm, scanning spacing 120μm.

[0123] Scanning strategy: Same as in Example 1.

[0124] 5. Post-processing techniques: Stress annealing: Annealing parameters are the same as in Example 1.

[0125] Hot isostatic pressing: This step is omitted.

[0126] Example 4 In this example, the printing parameters of the interface layer were gradient optimized while ensuring that the water distribution manifold meets the core performance requirements. The aim was to eliminate sudden changes in interface thermal stress, achieve dense bonding in the bonding area, and enhance the bonding strength of the interface.

[0127] The specific steps for preparing the manifold in this example are as follows: 1. Substrate: 316L stainless steel square tube, the same as in Example 1; 2. Powder: The same 316L stainless steel powder as in Example 1; 3. Pre-processing before printing: The pre-processing method is exactly the same as in Example 1.

[0128] 4. Grafting and printing core process parameters: Gradient interface layer process (layers 1-5): Layer 1: Laser power 415W, scanning speed 700mm / s, layer thickness 30μm, scanning spacing 90μm.

[0129] Layers 2-3: Laser power 380W, scanning speed 850mm / s, layer thickness 30μm, scanning spacing 90μm.

[0130] Layers 4-5: Laser power 365W, scanning speed 950mm / s, layer thickness 30μm, scanning spacing 90μm.

[0131] Main body printing process (6th layer and above): Laser power 350W, scanning speed 1200mm / s, layer thickness 30μm, scanning spacing 110μm.

[0132] Scanning strategy: Same as in Example 1.

[0133] 5. Post-processing techniques: Stress annealing: Annealing parameters are the same as in Example 1.

[0134] Hot isostatic pressing: This step is omitted.

[0135] Comparative Example 1 The only difference between the preparation method of the water distribution manifold in this example and that in Example 1 is that the main body of the pipe is not pre-treated by sandblasting in the pre-printing process step 3, but is only ultrasonically cleaned with alcohol. The remaining steps are the same as in Example 1.

[0136] Comparative Example 2 The only difference between the preparation method of the water distribution manifold in this example and that in Example 1 is that in step 4 of this example, the printing parameters of the interface layer and the main body of the branch nozzle are the same: laser power 350W, scanning speed 1200mm / s, printing thickness of each layer 30μm, and scanning spacing 110μm.

[0137] Comparative Example 3 (Traditional Brazing Process) The only difference between the preparation method of the water distribution manifold in this example and that in Example 1 is that: in this example, step 4 is: after the branch nozzle is machined by computer numerical control (CNC), it is brazed to the main body of the pipe using silver-based brazing filler metal (BAg-3) at 820°C.

[0138] Performance testing: The deformation at the top of the square tube, the branch nozzle position error, the sealing performance, the mechanical properties, and the fluid properties of the water distribution manifolds prepared in Examples 1-4 and Comparative Examples 1-3 were tested respectively. The specific test methods are as follows: Deformation at the top of the square tube: Place the finished product on a coordinate measuring machine (CMM). Using a height gauge, dial indicator, or laser displacement sensor, select multiple measurement points at equal intervals along the centerline of the top of the pipe body, and record the height deviation of each point relative to the theoretical plane. Calculate the maximum deformation per unit length (per meter).

[0139] Branch nozzle position error: A coordinate measuring machine is used. A coordinate system is established with the reference holes of the flanges at both ends of the main pipe body. Then, the actual three-dimensional coordinates of the center of the end face of each branch nozzle or the reference circle of the sealing groove are measured and compared with the theoretical design coordinates to calculate the positional deviation.

[0140] Helium mass spectrometry leak detection rate: Seal all interfaces of the water distribution manifold, leaving only one gas filling port. Fill the inner cavity with high-purity helium gas at a certain pressure (e.g., 0.5 MPa). Using the suction gun mode of the helium mass spectrometer leak detector, scan the outer surface of all welds (Comparative Examples 1-3) or grafting interfaces (Examples 1-4) at a constant speed. The instrument directly measures the leak rate.

[0141] Pressure Cycle Test: Connect the manifold to the hydraulic testing system, filling it with liquid (usually water or oil). The system performs periodic pressurization and depressurization according to a set program (e.g., 0.2MPa-1.5MPa) to simulate actual working conditions. Complete the set number of cycles (e.g., 10). 6 After (time), check for leaks or cracks.

[0142] Graft interface tensile strength: A standard tensile specimen containing a complete graft interface was fabricated by cutting a sample from the top of the water distribution manifold. The specimen was subjected to tension on a universal testing machine until fracture, and the maximum load was recorded. The tensile strength was calculated based on the specimen's cross-sectional area.

[0143] Graft interface shear strength: Samples are taken from the top of the manifold and processed into specialized shear specimens (such as single-lap shear specimens). A shear force parallel to the interface is applied on a testing machine until failure, and the shear strength is calculated.

[0144] Material density: Archimedes' displacement method was used. The dry weight of the sample was measured in air, and the apparent weight was measured after immersion in water. The actual volume and density were calculated based on the principle of buoyancy. The density percentage was obtained by comparing this with the theoretical density of the material.

[0145] Flow resistance (pressure drop): On a fluid test bench, connect the manifold to the circulation line. At a set flow rate (such as the corresponding design flow rate), use a high-precision pressure sensor to measure the stable pressure difference between the inlet and outlet. This pressure difference is the flow resistance. It is usually expressed as a percentage relative to the baseline product (i.e., Example 1) at the same flow rate.

[0146] Branch flow non-uniformity: Connect all branch nozzle outlets to independent turbine flow meters or mass flow meters. Run at the set total flow rate, and after stabilization, record the flow rate of each branch simultaneously.

[0147] Non-uniformity = (Maximum flow rate - Minimum flow rate) / Average flow rate × 100% The performance test results of the water-splitting manifolds of Examples 1 to 4 obtained according to the above test method are shown in Table 1 below, and the performance test results of the water-splitting manifolds of Comparative Examples 1 to 3 are shown in Table 2 below.

[0148] Table 1 Performance test results of the water distribution manifolds in Examples 1-4

[0149] Table 2 Performance test results of the water distribution manifolds in Comparative Examples 1-3

[0150] As shown in Tables 1-2, the water distribution manifolds prepared by the methods in Examples 1-4 have small top deformation (0.06-0.12 mm / m), branch nozzle position error within 0.15 mm, and helium mass spectrometry leak detection rate <8×10⁻⁶. -10 Pa·m 3 / s, can be accessed via 10 6 After pressure cycle testing, it exhibits excellent sealing performance. The tensile strength of the grafting interface is 480-535MPa, the shear strength is 370-420MPa, the material density is 99.7-99.85%, and the branch flow instability is within ±3.5%. It has significantly better mechanical, sealing, and fluid properties than comparative examples 1-3.

[0151] Comparative Example 1 did not undergo sandblasting treatment on the main body of the pipe. Metallographic examination at the contact point between the branch nozzle and the main body of the pipe showed (e.g.) Figure 2 As shown): there are localized unfused areas at the grafting interface, resulting in discontinuous bonding. The shear strength of the grafting interface is 285 MPa, only 71.6% of that in Example 1 (398 MPa); the helium mass spectrometry leak detection rate is 5.4 × 10⁻⁶. -7 Pa·m 3 / s, the sealing level drops significantly. This shows that sandblasting pretreatment to achieve an appropriately rough surface is a prerequisite for ensuring a stable and dense metallurgical bond between the laser molten pool and the substrate. Its absence will directly lead to a significant deterioration in the bonding strength and sealing reliability.

[0152] Comparative Example 2 uses the same laser printing parameters for both the interface layer and the branch nozzle body. Metallographic examination at the contact point between the branch nozzle and the pipe body shows (e.g.) Figure 3As shown in the figure): numerous pores were observed in the interface region, indicating poor density. Due to insufficient energy input during the interface layer printing process, effective micro-melting of the pipe body surface could not be achieved. The tensile and shear strengths of the grafting interface were significantly reduced, with the shear strength at 305 MPa, approximately 76.6% of that in Example 1. At 10... 6 In the secondary pressure cycle test, the failure occurred at the grafting interface, proving that this is the weak point. Therefore, printing the interface layer and the branch nozzle body using different laser printing parameters, with higher energy input for the interface layer, is key to achieving high-quality metallurgical interface bonding.

[0153] Comparative Example 3, using conventional brazing technology, showed a brazed joint shear strength of 245 MPa, significantly lower than Examples 1-3, at 10... 6 In the secondary pressure cycle test, 2 out of 24 brazed joints leaked, with a leakage rate of 1.8 × 10⁻⁶. -5 Pa·m 3 / s, and due to the non-smooth flow channel transition, the flow resistance is 25% higher than that of Example 1, and the flow rate non-uniformity is ±7.5%. In addition, the performance of Comparative Example 3 is inferior to that of Comparative Examples 1 and 2, further demonstrating that the laser melt printing process can significantly improve the various performance characteristics of the prepared water distribution manifold.

[0154] The shear strength of the grafting interface in Example 1 reached 398 MPa, equivalent to more than 98% of the strength of the base material, which is much higher than 285 MPa in Comparative Example 1 (without sandblasting pretreatment) and 245 MPa in Comparative Example 4 (traditional brazing). This is because the metallurgical bonding in this invention forms an interface region with a continuous transition in composition and microstructure, eliminating the abrupt compositional change zones present in traditional brazing. Its metallographic analysis is shown in the figure below. Figure 4 As shown, this results in a more uniform stress distribution under cyclic pressure loading. The sealing performance of traditional brazing processes relies on the perfect filling of micro-assembly gaps by the brazing filler metal; any insufficient filling will create potential leakage channels.

[0155] Metallographic images of the overlapping molten pool during the printing process of the water distribution manifold in Example 4 were examined using a metallographic microscope, as shown in the following figures. Figure 5 As shown, Figure 5 The two smaller images, a and b, are metallographic images of the overlapping molten pools measured along the printing direction with scales of 200 μm and 10 μm, respectively. Figure 5 The black arrows in the two smaller diagrams, a and b, point in the direction of laser selective melting of metal in 3D printing. Figure 5It can be seen that a good overlapping and interlocking structure is formed between adjacent printed molten pools. This microstructure proves that under the action of laser remelting, the newly formed printed layer can achieve complete metallurgical fusion with the solidified printed layer, eliminating the defects of incomplete fusion between different printed layers and ensuring the mechanical continuity of the branch nozzle body in the direction of laser selective melting of metal 3D printing.

[0156] The microstructure of the interface layer in Example 4 during printing was examined using scanning electron microscopy (SEM) images, specifically as follows: Figure 6 As shown, where, Figure 6 Figure a in the diagram shows the microstructure of the first layer (the first layer printed on the pipe body) to the third layer (the third layer printed on the pipe body) in the interface layer. Figure 6 Images b, c, and d in the image are magnified views of the areas within the red boxes in the first, second, and third layers of image a, respectively. Figure 6 It is evident that, through the rapid solidification characteristics of the laser selective melting process, fine equiaxed crystals are formed on the top of both the main body of the branch nozzle and the metallurgical bonding zone (i.e., the interface layer). This fine-grained structure (i.e., fine equiaxed crystals) is based on the Hall-Petch strengthening mechanism, namely, the effective obstruction of dislocation movement by numerous grain boundaries, significantly improving the local tensile strength of the water distribution manifold. Simultaneously, the rapid solidification process suppresses the formation of pores and loose defects in the water distribution manifold, ensuring that the density of the formed area reaches over 99.7% (i.e., porosity less than 0.3%), thereby eliminating potential crack sources and providing microstructural assurance for the high strength and high sealing performance of the water distribution manifold.

[0157] This invention completely eliminates the source of leakage—"assembly gaps"—from a physical structural perspective through integrated seamless molding technology. Examples 1 and 2 of this invention demonstrate helium mass spectrometry leak detection rates below 5 × 10⁻⁶. -10 Pa·m 3 / s and 2×10 -10 Pa·m 3 / s, achieving a high level of sealing standard. In contrast, the leakage rate of the conventional brazed component in Comparative Example 4 was as high as 1.8 × 10⁻⁶. -5 Pa·m 3 / s, and multiple leaks occurred during the pressure cycle test. The reason is that the metallurgical bonding zone formed by grafting and printing has a density of over 99.8% (comparative example 3 has a density of 99.65% without heat isostatic pressing). The microstructure is continuous and uniform, without defects such as porosity and lack of fusion that are characteristic of brazing, which fundamentally eliminates the formation of leakage paths.

[0158] The present invention provides Embodiment 1, in which a smooth flow channel transition exists between the main pipe body and the branch nozzle, reducing flow resistance by more than 20% and controlling the flow non-uniformity of each branch within ±2.5%, while the flow non-uniformity of the conventional brazed component in Comparative Example 4 is ±7.5%. The smooth transition between the main pipe body and the branch nozzle significantly reduces flow separation and eddy current generation, reduces local pressure loss, and ensures the uniformity of flow distribution in each branch, thereby improving liquid cooling efficiency and reducing pump power consumption at the system level.

[0159] Example 1 achieves a material utilization rate of 86%, with a comprehensive manufacturing cost approximately 60% of the overall 3D printing solution (Comparative Example 2), while shortening the production cycle by 40% compared to traditional brazing. Furthermore, this invention ensures high-quality grafting interfaces through sandblasting pretreatment of the pipe body and layered printing processes, while hot isostatic pressing post-treatment (Examples 1-2) further increases material density to over 99.8%, guaranteeing long-term product reliability. In Example 1, the deformation at the top of the square tube is controlled within 0.07 mm / m, and the branch nozzle position error is ±0.08 mm, significantly lower than the 0.35 mm / m and ±0.25 mm of traditional brazing in Comparative Example 4. The reason for this is that the 8mm × 8mm checkerboard scanning partition effectively disperses heat accumulation, avoiding warping deformation caused by localized overheating, and providing a reliable dimensional basis for subsequent assembly. This invention systematically solves the irreconcilable contradictions between structural integrity, sealing reliability, fluid performance, and economy in traditional water distribution manifolds through an innovative process route of "sandblasting pretreatment → interface layer / main body layer printing → post-processing".

[0160] In summary, the tensile strength of traditional brazed joints is typically only 60%-70% of that of the base material. This invention, through laser selective melting metal 3D printing, ensures that the room temperature tensile strength of the connection area between the branch nozzle and the pipe body is no less than 95% of the base material strength. Simultaneously, hot isostatic pressing effectively closes internal micropores, significantly improving its fatigue life and long-term service reliability, thus meeting the requirements of 10... 6 This invention addresses the issue of leakage rates exceeding 0.5% in traditional brazing processes by employing seamless, integrated molding technology to reduce the leakage rate to 10%. -9 Pa·m 3The system achieves near-per-second (helium leak detection level) sealing, meeting the stringent leakage rate requirements of single-phase immersion liquid cooling systems. Addressing the issue of traditional processes requiring 6-8 main steps, this invention simplifies the manufacturing process to 3 core steps (pipe body processing, grafting printing, and heat treatment), reducing the production cycle by over 40% and assembly time per unit by 60%, enabling a daily production capacity of over 50 sets. For brazing processes with deformation ≥0.3mm / m, this invention controls the overall deformation of the printed part to within 0.1mm / m, with a flatness error of ≤0.05mm on key mounting surfaces, ensuring plug-and-play compatibility with server quick connectors.

[0161] This invention controls the flow resistance of branch channels to within 10%, and the flow non-uniformity of each branch to within ±3%, while achieving noise control of ≤35dB, meeting the quiet operation requirements of data centers. Furthermore, the grafting interface of the water distribution manifold prepared in this invention maintains a corrosion level of 0 after undergoing a 2000-hour salt spray test in a coolant at 85℃ and pH=8.5, fundamentally eliminating the risk of electrochemical corrosion caused by brazing dissimilar materials.

[0162] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A water distribution manifold, comprising a main pipe body and at least two branch nozzles disposed on the main pipe body, wherein the main pipe body is in communication with the branch nozzles, characterized in that: The main pipe body and the branch nozzle are integrally formed and connected; The leakage rate of the water distribution manifold during helium mass spectrometry leak detection was less than 1×10⁻⁶. -9 Pa·m 3 / s; The tensile strength at the connection between the main pipe body and the branch nozzle is >450MPa; The branch nozzle contains equiaxed crystals.

2. The water distribution manifold according to claim 1, characterized in that: The average grain size of the equiaxed crystals is ≤5μm; And / or, the ratio between the transverse dimension and the longitudinal dimension of the equiaxed crystal is 1:(0.5-5).

3. The water distribution manifold according to claim 2, characterized in that: The branch nozzle includes a branch nozzle body and an interface layer; the branch nozzle body is integrally connected to the pipe body through the interface layer.

4. The water distribution manifold according to claim 3, characterized in that: The interface layer includes a first printing layer, a second printing layer, and a third printing layer stacked sequentially; the first printing layer is located on the pipe body. Preferably, in the first printed layer, the ratio between the lateral dimension and the longitudinal dimension of the equiaxed crystal is 1:(0.5-1.5). Preferably, in the second printed layer, the ratio between the lateral dimension and the longitudinal dimension of the equiaxed crystal is 1:(1.5-5). Preferably, in the third printing layer, the ratio between the lateral dimension and the longitudinal dimension of the equiaxed crystal is 1:(1.5-5).

5. The water distribution manifold according to any one of claims 1-4, characterized in that: The shear strength at the connection between the main pipe body and the branch nozzle is >350MPa; And / or, the density at the connection between the pipe body and the branch nozzle is ≥99.65%; And / or, the flow resistance of the manifold is ≤10%; And / or, the flow difference between at least two of the branch nozzles is ≤3.5%; And / or, the water distribution manifold is in 10 6 During the pressure cycle test, the number of leaks at the branch nozzles was 0; And / or, the deformation of the main surface of the pipe body is ≤0.15mm / m.

6. The method for preparing the water distribution manifold according to any one of claims 1 to 5, characterized in that: Includes the following steps: An interface layer is printed on the main body of the pipe using the selective laser melting metal 3D printing method. Then, the branch nozzle body is printed on the interface layer using the selective laser melting metal 3D printing method. After heat treatment, the water distribution manifold is obtained. The surface roughness Ra value of the main body of the pipe is 4~6μm; The laser power during the printing of the interface layer is greater than the laser power during the printing of the branch nozzle body.

7. The method for preparing a water distribution manifold according to claim 6, characterized in that: The interface layer is printed using at least one of the following parameters: (a1) The number of printing layers for the interface layer is 1 to 5; (a2) The laser power during the printing of the interface layer is 360~420W; (a3) The scanning speed during the printing of the interface layer is 650~1000mm / s; (a4) The scanning spacing during the printing of the interface layer is 80~110μm; (a5) The thickness of each layer is 20~50μm; (a6) The scanning strategy for printing the interface layer is partition jump and / or inter-layer rotation scanning; (a7) The interface layer is printed using gradient printing. When printing the first layer, the laser power is 410~420W and the scanning speed is 650~750mm / s; when printing the second and third layers, the laser power is 370~390W and the scanning speed is 800~900mm / s. When printing the fourth and fifth layers, the laser power is 360~370W and the scanning speed is 900~1000mm / s; And / or, The branch nozzle body is printed using at least one of the following parameters: (b1) The laser power during the printing of the branch nozzle body is 340~370W; (b2) The scanning speed during printing of the branch nozzle body is 1000~1500mm / s; (b3) The scanning spacing during the printing of the branch nozzle body is 100~130μm; (b4) The thickness of each layer during the printing of the branch nozzle body is 20~50μm; (b5) The scanning strategy for printing the branch nozzle body is partition jump and / or interlayer rotation scanning.

8. The method for preparing a water distribution manifold according to claim 6, characterized in that: The pipe body is surface treated before use to make the surface roughness Ra value of the pipe body 4~6μm; And / or, the temperature of the heat treatment is 800~1100℃; And / or, the heat treatment time is 1 to 6 hours.

9. The method for preparing a water distribution manifold according to claim 6, characterized in that: The preparation method further includes a hot isostatic pressing step, which is performed after the heat treatment step. Preferably, the temperature of the hot isostatic pressing treatment is 1000~1100℃; Preferably, the pressure of the hot isostatic pressing treatment is 90~110MPa; Preferably, the hot isostatic pressing treatment takes 2 to 6 hours.

10. The application of the water distribution manifold according to any one of claims 1 to 5 or the method for preparing the water distribution manifold according to any one of claims 6 to 9 in the field of liquid cooling systems or servers.

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