A water distribution manifold, method of making and use thereof

Abstract

The application belongs to the field of additive manufacturing, and specifically discloses a water distribution manifold, a preparation method thereof and application. The water distribution manifold comprises a pipeline body and at least two water distribution nozzles arranged on the pipeline body; the water distribution nozzles are in communication with the pipeline body; the water distribution nozzles are integrally connected with the pipeline body; the tensile strength of the connection between the pipeline body and the water distribution nozzles is greater than 285 MPa; and columnar dendrites are distributed along the printing direction at the connection position of the pipeline body and the water distribution nozzles. The preparation method in the application first prints a bonding layer on the pipeline body by using a gas shielded welding method, and then prints the water distribution manifold, so as to realize integrated metallurgical bonding, eliminate the interface weld structure, eliminate the air tightness hidden danger caused by the welding link, and solve the leakage problem of the water distribution manifold prepared by using the traditional brazing process.

Description

Technical Field

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

[0002] In the context of the rapid development of modern information technology, the performance and stability of data center servers, as core devices for data processing and storage, are of paramount importance. In recent years, the explosive growth in computing power demand from the digital economy has driven the power density of single data center servers from the traditional 500W / U to over 1500W / U, with AI servers even exceeding the 3000W / U threshold. The heat dissipation pressure brought by this high power density makes traditional air-cooling systems insufficient. Liquid cooling systems, with their advantages of high heat dissipation efficiency (4-6 times higher than air cooling) and low energy consumption (PUE can be reduced to below 1.1), have become the mainstream direction for data center cooling solutions.

[0003] As a core fluid distribution component of the liquid cooling system, the manifold is responsible for precisely distributing coolant to each heat-generating unit of the server and collecting the returning coolant. Its manufacturing precision and reliability directly determine the server's heat dissipation stability. Currently, the industry mainly uses a combination of traditional machining and welding processes to manufacture stainless steel server manifolds. High-precision components are first obtained through machining, and then the structure is assembled through welding.

[0004] Currently, most server rack manifold components are connected and formed using traditional welding processes. The specific process is as follows: First, the key components of the manifold (square tube and water inlet) are manufactured using traditional machining methods, and then precision-machined using a CNC machine. Next, the water inlet is precisely positioned and arranged on the surface of the stainless steel square tube, establishing the basic structure of the manifold. Finally, silver-based or copper-based brazing filler metal is used to complete the welding at high temperatures, forming a strong connection between the components. However, due to the limitations of the brazing process, the physical interface of the brazed joint has inherent defects (such as microscopic pores and lack of fusion), becoming a core hidden danger for coolant leakage and failing to meet the stringent sealing requirements of high-end servers. After welding, a comprehensive weld quality inspection must be carried out manually, and secondary repairs are required after defects are found, further increasing the complexity of the process. Although traditional brazing technology once met the basic requirements for manifold manufacturing, with technological iteration and increasing product quality requirements, its inherent defects have become increasingly significant, mainly in the following aspects: (1) Insufficient structural reliability and high risk of leakage during long-term use: During the brazing process, the weld is prone to defects such as micropores and lack of fusion. When the water distribution manifold is under water pressure circulation for a long time, Cl in the coolant - Under the corrosive effect of ions, stress corrosion cracking is easily triggered at weld defects, directly threatening the structural stability and service life of the manifold.

[0005] (2) Insufficient air tightness: During the brazing operation, the contact surface between the stainless steel square tube and the water outlet is prone to forming pores or incomplete welds due to oxidation reaction and residual impurities, resulting in a coolant leakage rate of more than 0.5%.

[0006] (3) High process complexity and imbalance between cost and efficiency: According to GB / T 985.1-2008 Joint Preparation Specification, traditional brazing requires a precise brazing gap of 0.05-0.2mm, which significantly increases the difficulty of assembly operations. At the same time, after welding, the surface oxide layer needs to be removed by pickling, which will generate wastewater containing heavy metals and acidic and alkaline substances. If it is treated in compliance with HJ2026-2013 "Technical Specification for Electroplating Wastewater Treatment Engineering", it will generate high hazardous waste treatment costs, further increasing manufacturing costs.

[0007] (4) Difficulty in controlling thermal deformation, resulting in additional process costs: Concentrated heating of local areas during brazing can easily cause deformation such as warping and shrinkage of stainless steel square tubes due to uneven heating, with deformation usually exceeding 0.3mm. In order to meet the dimensional requirements, an additional straightening process is required, which not only increases the manufacturing cost by 15-20%, but also extends the overall production cycle.

[0008] Therefore, in order to overcome at least one of the technical problems existing in the above-mentioned prior art, it is urgent to develop a new method for preparing water distribution manifolds. Summary of the Invention 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.

[0009] The second objective of this invention is to provide a method for preparing a water distribution manifold.

[0010] 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.

[0011] 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 water distribution nozzles disposed on the pipe body; the water distribution nozzles are in communication with the pipe body; the water distribution nozzles are integrally connected to the pipe body; The tensile strength at the connection between the main pipe body and the water distribution nozzle is >285MPa; Columnar dendrites are distributed along the printing direction at the connection point between the main pipe body and the water distributor.

[0012] In some embodiments of the present invention, the tensile strength at the connection between the pipe body and the water distributor is 285~370MPa; in some embodiments of the present invention, the tensile strength at the connection between the pipe body and the water distributor is 310~370MPa; in some embodiments of the present invention, the tensile strength at the connection between the pipe body and the water distributor is 350~370MPa; in some embodiments of the present invention, the tensile strength at the connection between the pipe body and the water distributor is 350~360MPa.

[0013] In some embodiments of the present invention, the water distribution manifold has undergone more than 6,000 cycles under a water pressure of 0-5 MPa without any leakage or cracking; in some embodiments of the present invention, the water distribution manifold has undergone more than 7,500 cycles under a water pressure of 0-5 MPa without any leakage or cracking.

[0014] In some embodiments of the present invention, when 1 MPa compressed air is introduced into the manifold and the pressure is maintained for 60 minutes, the leakage rate is 0~1.9 mL / min; in some embodiments of the present invention, when 1 MPa compressed air is introduced into the manifold and the pressure is maintained for 60 minutes, the leakage rate is 0~1.2 mL / min; in some embodiments of the present invention, when 1 MPa compressed air is introduced into the manifold and the pressure is maintained for 60 minutes, the leakage rate is 0~0.5 mL / min; in some embodiments of the present invention, when 1 MPa compressed air is introduced into the manifold and the pressure is maintained for 60 minutes, there is no gas leakage.

[0015] In some embodiments of the present invention, the leakage rate is 0~0.37% when 1MPa compressed air is introduced into the manifold and the pressure is maintained for 60 minutes; in some embodiments of the present invention, the leakage rate is 0~0.21% when 1MPa compressed air is introduced into the manifold and the pressure is maintained for 60 minutes; in some embodiments of the present invention, the leakage rate is 0~0.2% when 1MPa compressed air is introduced into the manifold and the pressure is maintained for 60 minutes; in some embodiments of the present invention, the leakage rate is 0% when 1MPa compressed air is introduced into the manifold and the pressure is maintained for 60 minutes.

[0016] In some embodiments of the present invention, the top deformation of the pipe body is 0~0.52mm; in some embodiments of the present invention, the top deformation of the pipe body is 0~0.18mm; in some embodiments of the present invention, the top deformation of the pipe body is 0.1~0.2mm.

[0017] In some embodiments of the present invention, the radial deviation of the water distributor position is ≤0.26mm; in some embodiments of the present invention, the radial deviation of the water distributor position is ≤0.22mm; in some embodiments of the present invention, the radial deviation of the water distributor position is ≤0.15mm; in some embodiments of the present invention, the radial deviation of the water distributor position is ≤0.1mm.

[0018] In some embodiments of the present invention, the axial deviation of the water distributor position is ≤0.3mm; in some embodiments of the present invention, the axial deviation of the water distributor position is ≤0.25mm; in some embodiments of the present invention, the axial deviation of the water distributor position is ≤0.18mm; in some embodiments of the present invention, the axial deviation of the water distributor position is ≤0.15mm; in some embodiments of the present invention, the axial deviation of the water distributor position is ≤0.12mm.

[0019] In some embodiments of the present invention, the porosity at the location of the water distributor is ≤0.5%.

[0020] In some embodiments of the present invention, the average particle size of the columnar dendrites is ≤15μm. In some embodiments of the present invention, columnar dendrites are distributed along the printing direction at the connection position between the pipe body and the water distributor.

[0021] In some embodiments of the present invention, the angle between the crystal axis of the columnar dendrite and the printing direction is ≤10°. The water distribution manifold of the present invention is manufactured by layer-by-layer printing using a gas metal arc welding method. Forced cooling with condensate creates a strong directional temperature gradient along the printing thickness direction. During solidification of the molten pool, the grains preferentially grow epitaxially along the direction of maximum heat flow (i.e., the printing deposition direction). When the angle between the crystal axis of the columnar dendrite and the printing direction is <10°, highly oriented continuous columnar dendrites are formed. The grains penetrate the bonding layer and the pipe matrix, with no obvious weak grain boundary regions at the interface, achieving true metallurgical integration. This significantly improves the bonding strength between the pipe body and the water distribution nozzle, increasing the tensile strength of the interface to over 310 MPa. Simultaneously, the regular grain arrangement and dense structure reduce defect channels, thereby simultaneously improving strength, fatigue life, and airtightness. If the angle between the crystal axis of columnar dendrites and the printing direction is greater than 10°, the grain orientation is disordered, forming approximately equiaxed crystals or oblique columnar crystals. The grain boundaries increase and become tortuous, easily becoming stress concentration points and leakage channels, resulting in a significant decrease in bonding strength and fatigue performance.

[0022] In this invention, the columnar dendrites at the connection between the pipe body and the water manifold are directional columnar dendrites growing along the printing direction. This is because during 3D printing, the molten pool rapidly dissipates heat along the heat flow direction (printing deposition direction), and the grains preferentially grow along the heat dissipation direction. The average grain size of these columnar dendrites is 10~15μm, and the angle between the crystal axis and the printing direction is ≤10° (strong orientation). This structure is a unique result of the 3D printing and condensation water condensation process used in this invention: traditional brazing / welding interfaces lack directional columnar dendrites, consisting only of random equiaxed crystals or a diffusion layer; while directional columnar dendrites can increase the tensile strength of the interface to over 310MPa, which is 10%~15% higher than traditional processes. In some embodiments of this invention, the material of the water manifold is stainless steel or titanium alloy.

[0023] In some embodiments of the present invention, the stainless steel is selected from 201 stainless steel, 304 stainless steel, and 316 stainless steel. The corrosion resistance and mechanical properties of the stainless steel pipe body are adapted to the working requirements of the liquid cooling system.

[0024] In some embodiments of the present invention, the titanium alloy is selected from at least one of TC4, TC6, TC11, TA1, TA2, and TA7.

[0025] In some embodiments of the present invention, the water distributor includes a water distributor body and a connecting layer; the water distributor body is integrally connected to the pipe body through the connecting layer. The connecting layer refers to the location where the pipe body and the water distributor are connected.

[0026] In this invention, the integral connection means that there are no obvious connection marks at the connection position, that is, no obvious weld seam, and there is mutual penetration of elements at the connection position between the pipe body and the water outlet to form a dense connection interface, and there are no obvious defects such as pores at the interface.

[0027] A second aspect of the present invention provides a method for preparing a water distribution manifold, comprising the following steps: At the water distribution point of the main pipe body, a bonding layer is formed by printing according to the printing path using the gas metal arc welding method. A water distribution nozzle is formed on the bonding layer by using a gas metal arc welding method according to the printing path. After cooling, it is heat-treated to obtain the water distribution manifold.

[0028] This invention applies the gas metal arc welding method to the integrated molding of the water distributor and the pipe body. After the metal welding wire is melted, it is deposited layer by layer through the welding gun according to the preset printing path, directly "growing" the water distributor on the pipe body. This eliminates the physical interface of the joint formed by the traditional brazing process, while greatly improving production efficiency, reducing post-processing steps, and significantly reducing production costs.

[0029] In some embodiments of the present invention, the preparation method includes the following steps: S1: Cool the main body of the pipe by introducing condensate; S2: At the water distribution point of the main body of the pipeline, the gas metal arc welding method is used to print according to the printing path. During the printing process, condensate is used for cooling to form a bonding layer. S3: The bonding layer is printed according to the printing path using the gas metal arc welding method to form a water nozzle. Cooling is carried out using condensate water during and after the printing process. S4: Heat treatment to obtain the water distribution manifold.

[0030] Cooling principle: This invention achieves precise control of the temperature gradient in the printing zone through staged cooling (S1 pre-cooling + S2 / S3 in-printing cooling): S1 uses condensate for pre-cooling, reducing the temperature of the main pipe body to 80-100℃, thus lowering the initial temperature difference during printing; in S2 and S3, the condensate flow rate is 1.5-2.5 LPM, and through flow cooling on the surface of the main pipe body, the temperature gradient between the printing zone (molten pool) and the substrate (i.e., the main pipe body) is controlled at 150-200℃ / mm, avoiding top deformation caused by thermal stress concentration (final deformation ≤0.52mm). The cooling rate causes the molten pool to solidify rapidly along the heat flow direction (printing deposition direction), and the grains preferentially grow along the heat dissipation direction, forming oriented columnar dendrites; these columnar dendrites must meet the following requirements: average grain size 10-15μm, angle between the crystal axis and the printing direction ≤10°, and no grain coarsening region.

[0031] The preparation method of this invention addresses the problem of deformation of the top of the pipe body caused by thermal stress generated by temperature gradient during gas metal arc welding. It introduces condensate cooling technology and, together with precise control of gas metal arc welding process parameters, achieves temperature control during the printing process, effectively solves the problem of thermal deformation control, effectively reduces the additional process costs caused by thermal deformation, and improves the performance of the water distribution manifold.

[0032] In some embodiments of the present invention, the printing is performed by melting metal welding materials through gas metal arc welding and then solidifying them layer by layer on the surface of the pipe body to form a bonding layer and the main body of the water outlet in sequence.

[0033] In some embodiments of the present invention, the welding material is stainless steel.

[0034] In some embodiments of the present invention, the welding material is made of the same material as the pipe body.

[0035] In some embodiments of the present invention, the material of the pipe body is stainless steel; in other embodiments, the material of the pipe body is selected from 201 stainless steel, 304 stainless steel, and 316 stainless steel. The corrosion resistance and mechanical properties of the stainless steel pipe body are suitable for the operation requirements of the liquid cooling system.

[0036] In some embodiments of the present invention, the main body of the pipe is a square tube; in some embodiments of the present invention, the main body of the pipe is a square tube with a cross-sectional side length of 20~40mm.

[0037] In some embodiments of the present invention, the wall thickness of the pipe body is 2-4 mm.

[0038] In some embodiments of the present invention, the length of the main body of the pipe is 300~1000mm.

[0039] In some embodiments of the present invention, a circular hole is provided on the top surface of the pipe body at intervals of 40-45mm from the center (as the water distribution position of the water distribution manifold, where a water distribution nozzle needs to be printed later).

[0040] In some embodiments of the present invention, the welding material used in the gas metal arc welding method is the same as the material of the pipe body, and the water nozzle and the pipe body are integrally metallurgically bonded after printing, without a physical bonding interface.

[0041] In some embodiments of the present invention, the arc current used in the gas metal arc welding method is 150~190A; in some embodiments of the present invention, the arc current used in the gas metal arc welding method is any value of 150A, 160A, 170A, 180A, 190A or a range formed by any two of them; in some embodiments of the present invention, the arc current used in the gas metal arc welding method is 160~180A.

[0042] In some embodiments of the present invention, the voltage used in the gas metal arc welding method is 19~23V; in some embodiments of the present invention, the voltage used in the gas metal arc welding method is any value of 19V, 20V, 21V, 22V, 23V or a range formed by any two of them; in some embodiments of the present invention, the voltage used in the gas metal arc welding method is 20~22V.

[0043] In some embodiments of the present invention, the deposition rate of the gas metal arc welding method during printing is 280~370 mm / min; in some embodiments of the present invention, the deposition rate of the gas metal arc welding method during printing is any value or a range formed by any two of 280 mm / min, 290 mm / min, 300 mm / min, 310 mm / min, 320 mm / min, 330 mm / min, 340 mm / min, 350 mm / min, 360 mm / min, and 370 mm / min; in some embodiments of the present invention, the deposition rate of the gas metal arc welding method during printing is 300~350 mm / min.

[0044] In some embodiments of the present invention, the heat input energy used in the gas metal arc welding method is 519~736 J / mm. The heat input energy calculation formula is: E=IU / V (I is current, U is voltage, and v is deposition rate). In this invention, the heat input energy is 519~736 J / mm, corresponding to the following process parameters: current 150~190A, voltage 19~23V, and deposition rate 280~370 mm / min.

[0045] In some embodiments of the present invention, the flow rate of the condensate in step S1 is 1~1.5 LPM; in some embodiments of the present invention, the flow rate of the condensate in step S1 is any value of 1 LPM, 1.1 LPM, 1.2 LPM, 1.3 LPM, 1.4 LPM, 1.5 LPM, or a range formed by any two of them; in some embodiments of the present invention, the flow rate of the condensate in step S1 is 1.1~1.3 LPM.

[0046] In this invention, the flow rate unit of condensate water, LPM, refers to L / min.

[0047] In some embodiments of the present invention, the flow rate of the condensate in steps S2 and S3 is 1.5~2.5 LPM.

[0048] In some embodiments of the present invention, in step S2, the flow rate of the condensate is any value or a range formed by any two of 1.5 LPM, 1.6 LPM, 1.7 LPM, 1.8 LPM, 1.9 LPM, 2.0 LPM, 2.1 LPM, 2.2 LPM, 2.3 LPM, 2.4 LPM, and 2.5 LPM; in some embodiments of the present invention, in step S2, the flow rate of the condensate is 1.8 to 2.2 LPM.

[0049] In some embodiments of the present invention, in step S3, the flow rate of the condensate is any value or a range formed by any two of 1.5 LPM, 1.6 LPM, 1.7 LPM, 1.8 LPM, 1.9 LPM, 2.0 LPM, 2.1 LPM, 2.2 LPM, 2.3 LPM, 2.4 LPM, and 2.5 LPM; in some embodiments of the present invention, in step S3, the flow rate of the condensate is 1.8 to 2.2 LPM.

[0050] This invention controls the temperature at the connection between the water distributor and the main pipe body to 200~280℃ by controlling the flow rate of condensate and the welding parameters of the gas metal arc welding. This avoids deformation of the main pipe body or poor connection between the water distributor and the main pipe body due to excessive heat input, and greatly reduces the impact of thermal stress on printing.

[0051] In some embodiments of the present invention, each end of the main body of the pipe is connected to a connector by welding, one connector serving as an inlet and the other as an outlet. When condensate cooling is required, the inlet is connected to a constant temperature water tank, and the outlet is equipped with a flow meter and a pressure valve to allow condensate to flow in for cooling, ensuring that the water flow direction is consistent with the printing direction and ensuring that heat is quickly dissipated during printing.

[0052] In some embodiments of the present invention, the temperature of the condensate is 20~25°C.

[0053] In some embodiments of the present invention, the flow meter has a range of 0~5 LPM.

[0054] In some embodiments of the present invention, the pressure of the pressure valve is 0.3~0.5MPa.

[0055] In some embodiments of the present invention, in step S2, the temperature at the connection between the water distributor and the main body of the pipe is 200~280℃.

[0056] In some embodiments of the present invention, in step S3, the temperature at the connection between the water distributor and the main pipe body is 200-280°C. In some embodiments of the present invention, the temperature of the water distributor during the printing process is 220-260°C.

[0057] In some embodiments of the present invention, the surface oxide layer of the pipe body needs to be removed before use, followed by sandblasting.

[0058] In some embodiments of the present invention, the particle size of the sand particles used in the sandblasting process is 80-120 mesh, and the gravel material is selected from at least one of garnet sand and corundum.

[0059] In some embodiments of the present invention, the pressure during the sandblasting process is 0.4~0.6 MPa.

[0060] In some embodiments of the present invention, the surface roughness Ra value of the pipe body is 5~7.5 μm; the surface roughness of the pipe body increases the contact area between the molten pool metal and the pipe substrate by 30%~40%, allowing the molten pool to fully fill the surface micro-depressions and form an anchoring effect; in some embodiments of the present invention, the surface roughness Ra value of the pipe body is 6~6.5 μm. If the roughness is too low, the contact area will be insufficient, and the bonding layer is prone to incomplete fusion defects; if the roughness is too high, the surface protrusions will be too high, the molten pool cannot be completely covered, and porosity is easily generated.

[0061] In some embodiments of the present invention, the printing path is constructed by building a model in three-dimensional software based on the structure of the water distribution manifold, and then importing the model into the slicing system. Using the main body of the pipe as the reference plane, printing parameters with a scanning interval of 0.1~0.5mm are constructed to form a printing path for the gas metal arc welding method.

[0062] In some embodiments of the present invention, the number of printing layers of the bonding layer is 1 to 5.

[0063] In some embodiments of the present invention, the height of the bonding layer is 1-5 mm. Bonding strength is ensured: a bonding layer of 1-5 mm can achieve sufficient remelting and interlayer metallurgical bonding through 2-5 layers of printing, avoiding insufficient bonding strength in single-layer printing. If the bonding layer height is >5 mm, printing time and material consumption will increase, and excessive interlayer heat accumulation can easily lead to grain coarsening; if the bonding layer height is <1 mm, a stable metallurgical bonding interface cannot be formed, and the bonding strength will drop below 280 MPa.

[0064] In some embodiments of the present invention, the scanning spacing of the bonding layer is smaller than the scanning spacing of the water separator.

[0065] In some embodiments of the present invention, the scanning spacing of the water divider during printing is 0.3~0.5mm.

[0066] In some embodiments of the present invention, the scanning spacing of the bonding layer during printing is 0.2~0.35mm.

[0067] In some embodiments of the present invention, the heat treatment is performed by first performing a first heat treatment at 250~350°C, then raising the temperature to 550~600°C for a second heat treatment, and then cooling.

[0068] In some embodiments of the present invention, during the printing process, printing is paused for 1 to 3 seconds for every 0.8 to 1.2 mm increase in the height of the water distribution nozzle.

[0069] 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.

[0070] The beneficial effects of the present invention are as follows: The preparation method of the present invention first prints a bonding layer on the main body of the pipe through gas metal arc welding, and then prints the water distribution manifold, which is an integrated metallurgical bond, eliminates the interface weld structure, eliminates the airtightness risk caused by the welding process, and solves the leakage problem of water distribution manifolds prepared by traditional brazing process.

[0071] Furthermore, the preparation method of this invention uses condensate to control the amount of printing deformation and achieve high density in the printed manifold. This reduces the cumulative thermal deformation during 3D printing to <0.2mm, reducing additional process costs caused by thermal deformation, improving printing efficiency and the performance of the printed manifold, reducing the time cost of manufacturing the manifold, and increasing the strength of the material bond and the fatigue life of the manifold after 3D printing. Specifically, the manifold prepared by the method of this invention has low top deformation (0.1~0.52mm), small axial and radial deviations, low leakage rate and leakage amount (leakage rate 0~0.21%, leakage amount 0~1.2mL / min), high strength (310~360MPa), and high fatigue life (6800~10800 cycles), making the manifold suitable for use in servers with high service life requirements. Attached Figure Description

[0072] Figure 1 This is a schematic diagram of the structure of the water distribution manifold prepared by the method in Example 1.

[0073] Figure 2 This is a cross-sectional view of the water distribution manifold prepared by the method in Example 1.

[0074] Figure 3 This is a metallographic diagram of the bonding layer in the water distribution manifold of Example 1. Detailed Implementation

[0075] 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.

[0076] Example 1 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 352 MPa. The manifold underwent 10,200 cycles of water pressure circulation from 0 to 5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 0 mL / min, or 0%. The deformation at the top of the main pipe body was 0.12 mm. The radial deviation of the water tap positions was ≤0.08 mm, and the axial deviation of the water tap positions was ≤0.1 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0077] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation DN25 304 stainless steel square tube conforming to GB / T 14976-2012 standard is selected, with a cross-sectional dimension of 20 mm × 20 mm, a wall thickness of 2 mm, and a length of 300 mm. A circular hole is machined every 42 mm from the center on the top surface of the square tube, evenly distributed. The oxide layer on the surface of the square tube is removed by CNC machining, and the surface roughness is pretreated to Ra=6.3μm. The printing area (within a diameter range of 20 mm) around the circular holes is sandblasted with 100-mesh garnet sand at a sandblasting pressure of 0.5 MPa.

[0078] 2. Condensate system connection Connect φ8mm (8mm diameter) stainless steel connectors to both ends of the square tube using an adapter, with one end as the water inlet and the other as the water outlet. Ensure that the water flow direction is consistent with the subsequent printing direction (printing the water nozzles sequentially from one end of the square tube to the other) to ensure rapid heat dissipation during printing. Connect the water inlet to a constant temperature water tank (preset water temperature 23℃) via a hose. Install a flow meter (range 0-5LPM, accuracy ±0.01LPM, LPM is liters / minute) and a pressure valve (set pressure 0.4MPa) at the water outlet. Start the system and allow it to flow for 30 minutes. Monitor the flow fluctuation to be ≤±0.1LPM and ensure there are no leaks at the connectors. 3. Water distribution nozzle model and slice A 3D model of a water distributor with a height of 25mm and an M10 thread was constructed in CAD software. After importing it into the slicing system, the center of the circular hole on the surface of the square tube was used as the reference point. The layer height was set to 0.8mm and the scanning interval to 0.4mm. The root of the water distributor (the area in contact with the square tube, with a height of 3mm) was scanned with a density of 0.3mm to generate the printing path.

[0079] 4. Integrated arc additive printing and real-time temperature control (1) Fixing the square tube and pre-circulating the condensate: Fix the square tube on the workbench with positioning fixture, and calibrate the parallelism between the axis of the square tube and the trajectory of the welding gun by using a laser positioning instrument. The deviation is ≤0.05mm. Turn on the condensate system and pre-circulate it at a flow rate of 1.2LPM. Monitor the surface temperature of the square tube by using an infrared thermal imager. When the temperature stabilizes and drops to 27℃ (temperature difference from the environment <5℃), start the gas metal arc welding (GMAW) power supply. (2) Printing of the bottom bonding layer of the water distributor (3 layers in total, 2.4 mm in height): A low current and slow speed strategy is adopted, with the arc current set to 160A, voltage to 20V, and deposition speed to 300mm / min. The condensate flow rate is maintained at 1.8 LPM. A thermocouple is attached 5 mm away from the printing area to monitor the temperature in real time. The temperature at the connection between the water distributor and the square tube is controlled to be ≤270℃ to avoid local overheating of the square tube. The welding torch is moved slowly along the preset path on the surface of the square tube so that the metal wire (304 stainless steel wire with a diameter of 1.2 mm) melts and forms a metallurgical bond with the surface of the square tube. During this stage, the condensate flow rate is maintained at 1.8 LPM. The temperature is monitored in real time by the thermocouple to control the bonding layer temperature to <280℃ to avoid local overheating of the square tube and stress. (3) Printing of the main structure of the water distributor (height 22.6mm): After the bonding layer is printed, adjust the parameters to arc current 170A, voltage 21V, deposition rate 320mm / min; linear energy 669J / mm; condensate flow rate 2.0LPM; take temperature field pictures every 10 seconds with an infrared thermal imager to ensure that the temperature at the connection between the water distributor and the square tube is stable at 240-250℃; If the temperature at the connection between the water tap and the square tube is >260℃, fine-tune the condensate flow rate to 2.3 LPM and reduce the arc current by 5 A to reduce heat input. If the temperature at the connection between the water distribution nozzle and the square tube is <220℃, reduce the condensate flow rate to 1.9 LPM and increase the deposition rate by 30 mm / min to avoid poor interlayer bonding caused by excessively rapid solidification of the molten pool.

[0080] During the printing process, a six-axis robot drives the welding torch to move along the printing path. Every 1mm increase in height (corresponding to 1-2 layers of stacking), a 2-second pause is taken to allow heat to dissipate through condensate, ensuring the vertical deviation of the water distribution nozzle is ≤0.1mm. (4) Cooling after printing: After the three water nozzles are printed in sequence, keep the condensate flow rate at 2.0 LPM for 15 minutes. When the overall temperature of the square tube and water nozzle drops to 48°C, reduce the flow rate by 0.5 LPM every 5 minutes to avoid residual stress between the square tube and water nozzle due to sudden temperature drop, until the flow rate is 0. Shut down the system, disassemble the condensate connector, and apply anti-rust oil to the interface to prevent corrosion. 5. Heat treatment A square tube with a water distribution nozzle is placed in a heat treatment furnace for annealing. The temperature is increased from room temperature to 300°C at a rate of 5°C / min and held for 20 minutes; then increased to 580°C at a rate of 3°C / min and held for 60 minutes; finally, the temperature is reduced to 300°C at a rate of 2°C / min and cooled to room temperature in the furnace, resulting in a stainless steel water distribution manifold. A schematic diagram of its structure is shown below. Figure 1 As shown, the cross-sectional schematic diagram is as follows: Figure 2 As shown.

[0081] The time consumption (i.e., the process time cycle) for each step in the preparation method of the stainless steel water distribution manifold in this example is shown in Table 1 below: Table 1. Processing Time Cycle

[0082] Example 2 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 355 MPa. The manifold was circulated 10,500 times under a water pressure of 0-5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 0 mL / min, or 0%. The deformation at the top of the main pipe body was 0.15 mm. The radial deviation of the water tap positions was ≤0.09 mm, and the axial deviation of the water tap positions was ≤0.11 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0083] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation DN25304 stainless steel square tube conforming to GB / T14976-2012 standard was selected, with a cross-sectional dimension of 30 mm × 30 mm, a wall thickness of 3 mm, and a length of 800 mm; a round hole was machined every 42 mm from the center on the top surface; after CNC pretreatment, the surface roughness Ra=6.3 μm, and the printing area was sandblasted (80-mesh sand, 0.4 MPa pressure); other aspects are the same as in Example 1.

[0084] 2. Condensate system connection Weld φ8mm connectors to both ends of the square tube. Connect the inlet end to a constant temperature water tank (water temperature 22℃) and install a flow meter and pressure valve (pressure 0.35MPa) at the outlet end. The pre-flow test flow fluctuation is ≤±0.1LPM; other aspects are the same as in Example 1.

[0085] 3. Water distribution nozzle model and slice: This step is the same as in Example 1. 4. Integrated arc additive printing and real-time temperature control Condensate pre-circulation: 1.2 LPM of condensate, and start the GMAW power supply when the temperature stabilizes at 26°C; Bonding layer printing (3 layers): current 170A, voltage 21V, deposition rate 330mm / min, condensate 1.8LPM, temperature at the connection between the water nozzle and the square tube ≤275℃; Main body printing: current 175A, voltage 21.5V, deposition rate 330mm / min, linear energy 684J / mm; condensate flow rate increased to 2.1LPM, temperature at the connection between the water nozzle and the square tube is 230-240℃; pause for 2 seconds after every 1mm increase, verticality deviation ≤0.1mm.

[0086] Cooling: After printing, allow the flow rate to decrease gradually to 2.0 LPM for 15 minutes, then allow it to cool to 45°C. The rest is the same as in Example 1.

[0087] 5. Heat treatment: This step is the same as in Example 1. Example 3 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 358 MPa. The manifold was circulated 10,800 times under a water pressure of 0-5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 0 mL / min, or 0%. The deformation at the top of the main pipe body was 0.18 mm. The radial deviation of the water tap positions was ≤0.10 mm, and the axial deviation of the water tap positions was ≤0.12 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0088] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation The 304 stainless steel square tube has a cross-sectional dimension of 40mm×40mm, a wall thickness of 4mm, a length of 1000mm, and a round hole every 42mm on the top surface. After pretreatment, it is sandblasted (120 mesh, 0.6MPa); other aspects are the same as in Example 1.

[0089] 2. Condensate system connection Water temperature 24℃, pressure 0.5MPa, pre-flow fluctuation ≤±0.1LPM; other parameters are the same as in Example 1. 3. Water distributor model and slice: This step is the same as in Example 1. 4. Integrated arc additive printing and real-time temperature control Condensate pre-circulation: 1.2 LPM, GMAW power supply started at 28°C; Bonding layer printing: current 180A, voltage 22V, deposition rate 350mm / min, condensate 1.8LPM, temperature at the connection between the water nozzle and the square tube ≤280℃; Main printing: current 180A, voltage 22V, deposition rate 350mm / min, linear energy 679J / mm; condensate 2.2LPM, temperature at the connection between the water nozzle and the square tube 220-230℃; The rest is the same as in Example 1.

[0090] 5. Heat treatment: This step is the same as in Example 1.

[0091] Example 4 (Condensate-free cooling additive manufacturing) This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 320 MPa. The manifold was circulated 7500 times under a water pressure of 0-5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 0 mL / min, or 0%. The deformation at the top of the main pipe body was 0.52 mm. The radial deviation of the water tap positions was ≤0.22 mm, and the axial deviation of the water tap positions was ≤0.25 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0092] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1. 2. Diverter nozzle model and slice, this step is the same as in Example 1. 3. Integrated arc additive printing. This step differs from step 4 in Example 1 only in that condensate is not used in this step. Specifically: After the square tube is fixed, the GMAW power supply can be started directly without pre-flow of condensate. Bonding layer printing: arc current 160A, voltage 20V, deposition rate 300mm / min, no condensation; temperature at the connection between the water nozzle and the square tube reaches 340℃. Main body printing: arc current 160A, voltage 20V, deposition rate 300mm / min, linear energy 640J / mm; no condensation; heat accumulation at the connection between the water nozzle and the square tube continues to accumulate, and the temperature rises to 360℃; After printing, allow it to cool naturally to room temperature. 4. Heat treatment: This step is the same as in Example 1.

[0093] Example 5 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 325 MPa. The manifold was circulated 7600 times under a water pressure of 0-5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 0 mL / min, or 0%. The deformation at the top of the main pipe body was 0.35 mm. The radial deviation of the water tap positions was ≤0.18 mm, and the axial deviation of the water tap positions was ≤0.22 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0094] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1; 2. Connect the condensate system; the remaining steps are the same as in Example 1. 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated arc additive printing and real-time temperature control. This step differs from step 4 in Example 1 only in that: Condensate pre-circulation: 1.2 LPM of condensate, temperature stabilized at 27°C; Bonding layer printing: arc current 160A, voltage 20V, deposition rate 300mm / min, condensate 1.5LPM, temperature at the connection between the water nozzle and the square tube reaches 310℃; Main body printing: arc current 170A, voltage 21V, deposition rate 320mm / min, linear energy 669J / mm; condensate 2.0LPM, temperature at the connection between the water nozzle and the square tube reaches 320℃; Cooling: After printing, allow the flow rate to decrease at 1.5 LPM for 15 minutes, then gradually reduce the flow rate. The specific steps for gradually reducing the flow rate are the same as in Example 1. 5. Heat treatment: This step is the same as in Example 1. Example 6 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 330 MPa. The manifold underwent 8200 cycles of water pressure circulation from 0 to 5 MPa without any leakage or cracking. When compressed air at 1 MPa was introduced into the manifold and held at that pressure for 60 minutes, the leakage rate was 1.2 mL / min. The deformation at the top of the main pipe body was 0.21 mm. The radial deviation of the water tap positions was ≤0.15 mm, and the axial deviation of the water tap positions was ≤0.18 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0095] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1; 2. Connect the condensate system; the remaining steps are the same as in Example 1. 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated arc additive printing and real-time temperature control. This step differs from step 4 in Example 1 only in that: Condensate pre-circulation: 1.2 LPM condensate, temperature 27°C; Bonding layer printing: condensate 2.5 LPM, temperature at the connection between the water nozzle and the square tube 170℃; Main body printing: condensate 2.5 LPM, temperature at the connection between the water nozzle and the square tube 180℃; Post-printing cooling: 2.5 LPM of condensate water circulates for 15 minutes; 5. Heat treatment: This step is the same as in Example 1.

[0096] Example 7 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 320 MPa. The manifold was circulated 8500 times under a water pressure of 0-5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 0.5 mL / min, or 0.13%. The deformation at the top of the main pipe body was 0.10 mm. The radial deviation of the water tap positions was ≤0.12 mm, and the axial deviation of the water tap positions was ≤0.15 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0097] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1; 2. Connection of the condensate system, this step is the same as in Example 1; 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated arc additive printing and real-time temperature control. This step differs from step 4 in Example 1 only in that: Condensate pre-circulation: 1.2 LPM of condensate, 27°C, start the GMAW power supply; Bonding layer printing (3 layers): Arc current 150A, voltage 20V, deposition rate 300mm / min, cooling water 1.8LPM, temperature controlled at 230℃; due to insufficient current, the molten pool was not fully melted, and signs of non-fusion between layers were observed. Main printing: current 150A, voltage 20V, deposition rate 300mm / min, linear energy 600J / mm; condensate 1.8LPM, temperature at the connection between the water nozzle and the square tube 220-230℃; 5. Heat treatment: This step is the same as in Example 1. Example 8 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 340 MPa. The manifold was circulated 9000 times under a water pressure of 0-5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 0 mL / min, or 0%. The deformation at the top of the main pipe body was 0.28 mm. The radial deviation of the water tap positions was ≤0.20 mm, and the axial deviation of the water tap positions was ≤0.23 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0098] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1; 2. Connection of the condensate system, this step is the same as in Example 1; 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated arc additive printing and real-time temperature control. This step differs from step 4 in Example 1 only in that: Condensate pre-circulation: 1.2 LPM condensate, temperature 27°C; Bonding layer printing: current 190A, voltage 20V, deposition rate 300mm / min, condensate 1.8LPM, temperature at the connection between the water nozzle and the square tube reaches 350℃; Main body printing: current 190A, voltage 20V, deposition rate 300mm / min, linear energy 760J / mm; condensate 1.8LPM, temperature at the connection between the water nozzle and the square tube 360℃, obvious thermal deformation in some parts of the square tube; 5. Heat treatment: This step is the same as in Example 1. Example 9 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 315 MPa. The manifold underwent 8200 cycles of water pressure circulation from 0 to 5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 0.8 mL / min, or 0.21%. The deformation at the top of the main pipe body was 0.13 mm. The radial deviation of the water tap positions was ≤0.15 mm, and the axial deviation of the water tap positions was ≤0.18 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0099] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1; 2. Connection of the condensate system, this step is the same as in Example 1; 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated arc additive printing and real-time temperature control. This step differs from step 4 in Example 1 only in that: Bonding layer printing: current 160A, voltage 19V, deposition rate 300mm / min, condensate 1.8LPM, poor arc stability, uneven molten pool spreading; Main printing: current 160A, voltage 19V, deposition rate 300mm / min, linear energy 608J / mm; condensate 1.8LPM, temperature at the connection between the water nozzle and the square tube 240-250℃; 5. Heat treatment: This step is the same as in Example 1. Example 10 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 330 MPa. The manifold was circulated 8800 times under a water pressure of 0-5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 0.7 mL / min, or 0.18%. The deformation at the top of the main pipe body was 0.14 mm. The radial deviation of the water tap positions was ≤0.18 mm, and the axial deviation of the water tap positions was ≤0.20 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0100] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1; 2. Connection of the condensate system, this step is the same as in Example 1; 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated arc additive printing and real-time temperature control. This step differs from step 4 in Example 1 only in that: Bonding layer printing: current 160A, voltage 23V, deposition rate 300mm / min, condensate 1.8LPM, arc energy dispersion, and molten pool edge oxidation; Main printing: current 160A, voltage 23V, deposition rate 300mm / min, linear energy 736J / mm; condensate 1.8LPM, temperature at the connection between the water nozzle and the square tube 250-260℃; 5. Heat treatment: This step is the same as in Example 1. Example 11 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 345 MPa. The manifold was circulated 8500 times under a water pressure of 0-5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 0 mL / min, or 0%. The deformation at the top of the main pipe body was 0.16 mm. The radial deviation of the water tap positions was ≤0.10 mm, and the axial deviation of the water tap positions was ≤0.12 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0101] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1; 2. Connection of the condensate system, this step is the same as in Example 1; 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated arc additive printing and real-time temperature control. This step differs from step 4 in Example 1 only in that: Bonding layer printing: current 160A, voltage 20V, deposition rate 280mm / min, condensate 1.8LPM, temperature at the connection between the water nozzle and the square tube reaches 290℃; Main printing: current 160A, voltage 20V, deposition rate 280mm / min, linear energy 686J / mm; condensate 1.8LPM, temperature at the connection between the water nozzle and the square tube 280-290℃; 5. Heat treatment: This step is the same as in Example 1.

[0102] Example 12 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 325 MPa. The manifold underwent 7800 cycles of water pressure circulation from 0 to 5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 0.6 mL / min, or 0.16%. The deformation at the top of the main pipe body was 0.11 mm. The radial deviation of the water tap positions was ≤0.16 mm, and the axial deviation of the water tap positions was ≤0.19 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0103] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1; 2. Connection of the condensate system, this step is the same as in Example 1; 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated arc additive printing and real-time temperature control. This step differs from step 4 in Example 1 only in that: Bonding layer printing: current 160A, voltage 20V, deposition rate 370mm / min, cooling water 1.8LPM, the melt pool did not completely solidify before it accumulated; Main printing: current 160A, voltage 20V, deposition rate 370mm / min, linear energy 519J / mm; condensate 1.8LPM, temperature at the connection between the water nozzle and the square tube 220-230℃; 5. Heat treatment: This step is the same as in Example 1.

[0104] Example 13 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 305 MPa. The manifold underwent 7000 cycles of water pressure circulation from 0 to 5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 1.8 mL / min, or 0.32%. The top deformation of the main pipe body was 0.18 mm. The radial deviation of the water tap positions was ≤0.21 mm, and the axial deviation of the water tap positions was ≤0.24 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0105] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, which differs from step 4 in Example 1 only in that the surface roughness is pretreated to Ra=5.2μm; 2. Connection of the condensate system, this step is the same as in Example 1; 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated electric arc additive printing and real-time temperature control, this step is the same as in Example 1; 5. Heat treatment: This step is the same as in Example 1.

[0106] Example 14 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 295 MPa. The manifold was circulated 6500 times under a water pressure of 0-5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 2.1 mL / min, or 0.37%. The deformation at the top of the main pipe body was 0.22 mm. The radial deviation of the water tap positions was ≤0.23 mm, and the axial deviation of the water tap positions was ≤0.26 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0107] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, which differs from step 4 in Example 1 only in that the surface roughness is pretreated to Ra=7.3μm; 2. Connection of the condensate system, this step is the same as in Example 1; 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated electric arc additive printing and real-time temperature control, this step is the same as in Example 1; 5. Heat treatment: This step is the same as in Example 1.

[0108] Example 15 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 285 MPa. The manifold was circulated 6000 times under a water pressure of 0-5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 1.5 mL / min, or 0.27%. The deformation at the top of the main pipe body was 0.15 mm. The radial deviation of the water tap positions was ≤0.19 mm, and the axial deviation of the water tap positions was ≤0.22 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0109] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1; 2. Connection of the condensate system, this step is the same as in Example 1; 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated arc additive printing and real-time temperature control. The only difference between this step and step 4 in Example 1 is that only one layer (0.8mm high) is printed on the bottom bonding layer of the water distributor. 5. Heat treatment: This step is the same as in Example 1.

[0110] Example 16 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 300 MPa. The manifold underwent 6800 cycles of water pressure circulation from 0 to 5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 1.7 mL / min, or 0.30%. The deformation at the top of the main pipe body was 0.28 mm. The radial deviation of the water tap positions was ≤0.25 mm, and the axial deviation of the water tap positions was ≤0.29 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0111] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1; 2. Connection of the condensate system, this step is the same as in Example 1; 3. Diverter nozzle model and slice, this step is the same as in Example 1; 4. Integrated arc additive printing and real-time temperature control. This step differs from step 4 in Example 1 only in that: eight layers (6.4mm high) are printed on the bottom bonding layer of the water distributor. 5. Heat treatment: This step is the same as in Example 1.

[0112] Example 17 This example provides a stainless steel manifold, including a main pipe body and twelve water taps installed on the main pipe body. The water taps are connected to the main pipe body and are integrally formed with the main pipe body. The tensile strength at the connection between the main pipe body and the water taps is 310 MPa. The manifold underwent 6800 cycles of water pressure circulation from 0 to 5 MPa without any leakage or cracking. When 1 MPa compressed air was introduced into the manifold and the pressure was maintained for 60 minutes, the leakage rate was 1.9 mL / min, or 0.32%. The deformation at the top of the main pipe body was 0.38 mm. The radial deviation of the water tap positions was ≤0.26 mm, and the axial deviation of the water tap positions was ≤0.30 mm, as shown in Table 1. The material of the manifold is stainless steel.

[0113] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Substrate preparation, this step is the same as in Example 1; 2. Forced cooling with condensate water is eliminated; air cooling is used to prepare the water distribution manifold. 3. Water nozzle model and slicing, this step is the same as in Example 1; 4. Integrated electric arc additive printing and air-cooling control (only the cooling method is changed) (1) Square tube fixing and air-cooled pre-flow The condensate was replaced with a pre-flow forced air cooling system, and compressed air (pressure 0.4MPa, wind speed 15m / s) was used to pre-purge the entire surface of the square tube. Other operations and parameters were the same as in Example 1.

[0114] (2) Printing of the bottom bonding layer of the water distributor The condensate cooling was cancelled and replaced with forced air cooling and continuous blowing. The air cooling speed was maintained at 15m / s. A thermocouple was attached 5mm away from the printing area to monitor the temperature in real time. The temperature at the connection between the water nozzle and the square tube naturally rose to 320~350℃ (no active temperature control, only passive heat dissipation by air cooling). Other operations and parameters were the same as in Example 1. (3) Printing of the main structure of the water distribution nozzle The condensate cooling was changed to maintain a forced air cooling wind speed of 15m / s; the temperature field was photographed every 10 seconds using an infrared thermal imager, and the temperature at the connection between the water nozzle and the square tube naturally stabilized at 300~330℃. Other operations and parameters were the same as in Example 1. (4) Cooling after printing After the water distributor nozzle is printed, maintain a forced air cooling speed of 15 m / s and continue blowing for 15 minutes. When the overall temperature of the square tube and water distributor nozzle drops to 48℃, reduce the air speed by 3 m / s every 5 minutes to avoid residual stress between the square tube and water distributor nozzle due to sudden temperature drop, until the air speed is 0. Turn off the system, disassemble the fixture, and apply anti-rust oil to the interface to prevent corrosion. After printing, the microstructure observation results show that the angle between the columnar dendrites and the printing direction is 15°~20°.

[0115] 5. Heat treatment: This step is the same as in Example 1.

[0116] Comparative Example 1 (Traditional Brazing) This example provides a stainless steel manifold, including a main pipe body and twelve manifold nozzles installed on the main pipe body. The manifold nozzles are connected to the main pipe body. The tensile strength at the connection between the main pipe body and the manifold nozzles is 280 MPa. The manifold underwent 5000 cycles of water pressure circulation from 0 to 5 MPa without leakage or cracking. When compressed air at 1 MPa was introduced into the manifold and held at that pressure for 60 minutes, the leakage rate was 12 mL / min, a leakage rate of 3.2%. The top deformation of the main pipe body was 0.75 mm. The radial deviation of the manifold nozzle positions was ≤0.35 mm. The axial deviation of the manifold nozzle positions was ≤0.40 mm, as detailed in Table 1. The manifold is made of stainless steel.

[0117] This example provides a method for preparing a stainless steel water distribution manifold, including the following steps: 1. Machining of base materials and parts The same 304 stainless steel square tube as in Example 1 was selected (cross-section size 20mm×20mm, wall thickness 2mm, length 300mm); M10 threaded water distributor nozzle (material 304 stainless steel) was CNC machined, and the bottom of the water distributor nozzle was machined to have an arc-shaped surface that fits the surface of the square tube, with a roughness Ra=3.2μm. 2. Assembly positioning Align the water distributor with the round hole on the top surface of the square tube and fix it with a positioning fixture to ensure that the axis of the water distributor is perpendicular to the square tube, leaving a 0.1mm brazing gap (compliant with GB / T985.1-2008). 3. Brazing connection Using silver-based brazing filler metal (Ag-Cu-Zn, containing 72% Ag), the assembled workpiece is placed in a brazing furnace, heated to 880℃, held for 15 minutes, and then cooled to room temperature with the furnace. 4. Heat treatment The weld and surface are polished to remove the oxide scale; the residual oxide layer is removed by pickling (5% nitric acid solution), rinsed with water after pickling, and then passivated; finally, the threads of the water distributor are cleaned to obtain the water distribution manifold.

[0118] The time cycle for traditional brazing is shown in Table 2 below: Table 2 Time Cycle of Traditional Brazing Process

[0119] Performance testing: The performance of the water distribution manifolds prepared in Examples 1-17 and Comparative Example 1 were tested according to the following test methods. The specific test methods are as follows: Dimensional accuracy inspection: Take points every 20mm along the length of the square tube at the top of the tube and measure the maximum warping (i.e., the top deformation); at the same time, use a coordinate measuring machine to measure the radial / axial deviation of the water nozzle with the axis of the square tube as the reference. Sealing test: 1.0MPa compressed air is introduced into the water outlet interface and pressure is maintained for 60 minutes to observe the leakage. The leakage amount (volume) and leakage rate (ratio) are different characterization methods of the same performance. Leakage rate = leakage amount / total amount of gas introduced × 100%.

[0120] Bond strength test: The bond strength between the water distributor and the square tube is tested by a pull-out test; Fatigue test: Circulate the components under water pressure of 0-0.5MPa and observe for cracks and leaks. Record the number of cycles when cracks or leaks occur. The performance data of Examples 1-17 and Comparative Example 1, obtained according to the above test methods, are shown in Table 3 below.

[0121] Table 3 Performance data of Examples 1-17 and Comparative Example 1

[0122] As shown in Table 3, the water distribution manifold prepared by the method of the present invention has a low top deformation (0.1~0.52mm), small axial and radial deviations, low leakage rate and leakage volume (leakage rate 0~0.37%, leakage volume 0~2.1mL / min), high strength (285~360MPa), and high fatigue life (6000~10800 cycles).

[0123] Analyzing the deformation at the top of the square tube, the top deformation of the manifolds prepared by the methods in Examples 1-3 and Examples 6-16 (0.10-0.28 mm) was relatively small, all less than 0.3 mm. Example 4 did not use condensate for cooling, so its thermal stress could not be offset, resulting in a large deformation (0.52 mm). Example 5 had a small condensate flow rate, resulting in insufficient cooling and a large thermal deformation (top deformation of 0.35 mm). Example 6 had a large condensate flow rate and a small top deformation (0.21 mm), but its over-cooling resulted in incomplete fusion of the molten pool. Example 8 used a higher current, and the top deformation met the standard (0.28 mm), but it caused local heat input overload and uneven heating, resulting in thermal expansion differences. Example 17 used natural air cooling, which was less effective than condensate cooling, with a top deformation of 0.38 mm. Comparative Example 1 used a traditional brazing process, which, although without printing thermal stress, still had a high top deformation (0.75 mm), and its deformation originated from the brazing cooling process.

[0124] Analyzing the position of the water distribution nozzles, the radial and axial deviations of the water distribution nozzles in the manifolds produced by the methods in Examples 1-17 are smaller than those in Comparative Example 1, indicating higher forming accuracy. Comparative Example 1, using a traditional brazing process, has larger brazing joint errors and lower forming accuracy. Example 4 did not use condensate for cooling, resulting in uncompensated thermal stress and thermal deformation leading to positional shifts, thus causing larger radial and axial deviations. Example 5, with its smaller condensate flow rate, also experienced positional shifts due to thermal deformation, with both radial and axial deviations increasing compared to Examples 1-3. Example 6, with its larger condensate flow rate, experienced excessive cooling that accelerated molten pool solidification, causing print layer shifts and further increasing both radial and axial deviations compared to Examples 1-3. Example 7... In Example 8, a lower current resulted in insufficient line energy, causing slight localized detachment during printing and leading to positional deviations, which in turn resulted in increased radial and axial deviations compared to Examples 1-3. In Example 9, a higher current resulted in line energy overload, causing warping of the square tube and offset of the printing reference surface, which in turn resulted in increased radial and axial deviations compared to Examples 1-3. In Example 10, a higher arc voltage resulted in poor arc stability, leading to arc breakage or deflection, which in turn resulted in increased radial and axial deviations compared to Examples 1-3. In Example 12, a faster deposition rate caused slight offset of the unsolidified molten pool, which in turn resulted in increased radial and axial deviations compared to Examples 1-3. In terms of sealing performance, compared with Comparative Example 1, Examples 1-17 all exhibited higher sealing performance. Specifically, the water distribution manifolds prepared by the methods in Examples 1-5, Example 8, and Example 11 all demonstrated high sealing performance, with a leakage volume of 0 mL and a leakage rate of 0%. In contrast, Comparative Example 1, using a traditional brazing process, resulted in micro-gaps in the weld seam, leading to a high leakage volume and leakage rate. Example 6 had a large condensate flow rate, and insufficient metallurgical bonding between layers created leakage channels, resulting in a high leakage volume. Example 7 had a low arc current, leading to insufficient molten pool energy and the formation of micropores. In Example 9, the low arc voltage and unstable arc resulted in poor molten pool formation quality and discontinuous interlayer overlap, leading to micro-gaps and thus a high leakage rate and leakage volume. In Example 10, the high arc voltage caused the arc energy to disperse, resulting in the formation of a Fe2O3 film on the surface of the square tube, which hindered the diffusion of metal atoms. Oxide inclusions appeared between layers, becoming leakage channels, thus leading to a high leakage rate and leakage volume. In Example 12, the fast deposition rate led to excessively rapid solidification of the molten pool, resulting in cold shut defects between layers, thus leading to a high leakage rate and leakage volume.

[0125] From the perspective of tensile strength analysis, compared with Comparative Example 1, the water manifolds prepared in Examples 1-17 all have higher tensile strength, with values ​​≥285MPa. Among them, the tensile strength of Examples 1-3 is ≥350MPa, and the tensile strength of Examples 4-12 is ≥310MPa, all higher than that of the water manifold prepared in Comparative Example 1. Comparative Example 1 uses a traditional brazing process, and the weld is a weak point, resulting in a significant reduction in the tensile strength of the weld. Example 5 uses a smaller condensate flow rate, leading to heat accumulation in the printing area, abnormal grain growth, and weakened intergranular bonding, thus reducing the tensile strength. Example 6 uses a larger condensate flow rate, resulting in insufficient metallurgical bonding between layers and cold shut defects, further reducing the tensile strength. Example 7 uses a lower arc current, resulting in insufficient melting of metal particles and insufficient metallurgical bonding, leading to a reduction in tensile strength. Example 8 uses a larger arc current, resulting in excessive heat input and residual thermal stress at the joint. At the same time, local overheating causes grain growth and a slight decrease in grain boundary strength. Example 9: The arc voltage was too low, resulting in discontinuous interlayer overlap and the formation of local weak areas, leading to a decrease in tensile strength. Example 10: A higher arc voltage was used, and the dispersed arc caused the surface of the square tube to re-oxidize, forming an oxide brittle film between the bonding layers. During drawing, this brittle film broke first, causing interlayer separation. At the same time, the dispersed arc reduced the fusion depth of the molten pool, resulting in a decrease in the effective bonding depth and further reducing the tensile strength. Example 11: The deposition rate was relatively low, and overheating in the printing area caused the grains to grow larger, leading to a decrease in intergranular bonding force and a slight decrease in tensile strength. Example 12: The deposition rate was relatively high, and insufficient interlayer bonding led to a decrease in bonding strength.

[0126] In terms of fatigue life, the water manifolds prepared by the methods in Examples 1 to 12 all have high fatigue life. They can withstand more than 7,500 cycles of 0-0.5MPa water pressure without cracking or leakage, which is significantly better than Comparative Example 1. The water manifolds in Examples 1 to 3 even achieved more than 10,000 cycles of 0-0.5MPa water pressure without cracking or leakage. Comparative Example 1 uses a traditional brazing process, and the presence of micro-gaps at the weld location significantly reduces fatigue life. In Example 5, the low condensate flow rate and overheating lead to a decrease in molten pool density, reducing fatigue resistance. In Example 7, the low current results in interlayer porosity, causing stress concentration and reducing fatigue resistance. In Example 8, the high current leads to residual thermal stress, resulting in decreased fatigue performance. In Example 9, the low voltage causes discontinuous interlayer overlap, forming stress concentration zones under cyclic stress, thus reducing fatigue life. In Example 10, the high voltage causes oxide inclusions to become crack initiations under cyclic stress, reducing fatigue life. In Example 11, the low deposition rate and excessively long hot residence time cause the 304 stainless steel grains to enlarge, leading to a decrease in grain boundary strength. In Example 12, the high deposition rate and overheating lead to a decrease in molten pool density, reducing fatigue resistance.

[0127] Metallographic microscopy was used to examine the metallographic structure of the manifold bonding layer in Example 1, as shown in the image below. Figure 3 As shown, by Figure 3 It is known that in Example 1, columnar dendrites are directionally grown at the connection point between the main body of the water manifold and the main body of the pipe (i.e., the bonding layer) along the printing direction (i.e., the stress direction), with an average grain size ≤15μm and no grain coarsening region (grain size fluctuation ≤2μm). Tests showed that Examples 2-17 have columnar dendrites with similar structures to Example 1. Because columnar dendrites are directionally grown at the bonding layer, the grain boundary slip resistance is high, increasing tensile strength; and the smaller grain size and greater number of grain boundaries hinder crack propagation. Combined with the uniform structure without coarsening regions, local stress concentration is avoided. Microscopic observation of the water manifolds after printing in Examples 1-3 revealed that the angle between the columnar dendrites and the printing direction was ≤10°; microscopic observation of the water manifolds after printing in Example 17 revealed that the angle between the columnar dendrites and the printing direction was 15°~20°.

[0128] Using Keyence equipment, the porosity of the main body of the water manifold in Examples 1 to 17 was tested by metallographic method. The porosity of all the main bodies of the water manifold was ≤0.5%, which has extremely high density and further improves the sealing performance and mechanical properties of the water manifold.

[0129] In summary, the performance comparison between the manifold prepared by the method of this invention and the manifold prepared by the existing brazing process is shown in Table 4 below: Table 4. Performance comparison of water distribution manifolds prepared by the method of the present invention and those prepared by existing brazing processes.

[0130] The preparation method of this invention employs GMAW welding, which enables the water manifold and square tube to form an atomic-level metallurgical bond (interlayer density ≥99.5%). Combined with heat treatment to eliminate porosity, this completely eliminates weld interface defects. The water manifolds prepared by the methods in Examples 1-5, 8, and 11 can achieve zero leakage after holding a pressure of 1.0 MPa for 60 minutes (compared to a leakage rate of 3.2% for traditional brazing). Regarding thermal deformation and dimensional accuracy, the method utilizes a condensate-stabilized temperature field and controlled printing process parameters. During printing, the condensate forms a flow path inside the square tube, carrying away heat from the printing area in real time, ensuring a stable surface temperature of the square tube during printing. This results in the deformation at the top of the square tube being only 23.1% of that achieved with traditional brazing. In terms of material properties, the integrated printing structure combined with the condensate cooling process results in a tensile strength ≥300 MPa, with some examples reaching ≥350 MPa (compared to only 278 MPa for brazing). Simultaneously, the fatigue life is increased from ≤5000 cycles to ≥6000 cycles, with some examples exceeding 10000 cycles.

[0131] 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 pipe body and at least two water distribution nozzles disposed on the pipe body; the water distribution nozzles being in communication with the pipe body; characterized in that: The water distribution nozzle is integrally formed and connected to the main body of the pipe; The tensile strength at the connection between the main pipe body and the water distribution nozzle is >285MPa; Columnar dendrites are distributed along the printing direction at the connection point between the main pipe body and the water distributor.

2. The water distribution manifold according to claim 1, characterized in that: The average grain size of the columnar dendrites is ≤15μm; preferably, the angle between the crystal axis of the columnar dendrites and the printing direction is ≤10°.

3. The water distribution manifold according to claim 1, characterized in that: The water distribution manifold circulated for more than 6,000 cycles under a water pressure of 0-5 MPa without any leakage or cracks. And / or, when 1MPa compressed air is introduced into the water distribution manifold and the pressure is maintained for 60 minutes, the leakage rate is 0~2.1mL / min; And / or, the leakage rate is 0~0.37% when 1MPa compressed air is introduced into the water distribution manifold and the pressure is maintained for 60 minutes; And / or, the top deformation of the pipe body is 0~0.52mm; And / or, the radial deviation of the position of the water distributor is ≤0.26mm; And / or, the axial deviation of the position of the water distributor is ≤0.3mm; And / or, the porosity at the location of the water distributor is ≤0.5%.

4. The method for preparing the water distribution manifold according to any one of claims 1 to 3, characterized in that: Includes the following steps: At the water distribution point of the main pipe body, a bonding layer is formed by printing according to the printing path using the gas metal arc welding method. A water distribution nozzle is formed on the bonding layer by using a gas metal arc welding method according to the printing path. After cooling, it is heat-treated to obtain the water distribution manifold.

5. The method for preparing a water distribution manifold according to claim 4, characterized in that: The preparation method includes the following steps: S1: Cool the main body of the pipe by introducing condensate; S2: At the water distribution point of the main body of the pipeline, the gas metal arc welding method is used to print according to the printing path. During the printing process, condensate is used for cooling to form a bonding layer. S3: The bonding layer is printed according to the printing path using the gas metal arc welding method to form a water nozzle. Cooling is carried out using condensate water during and after the printing process. S4: Heat treatment to obtain the water distribution manifold.

6. The method for preparing a water distribution manifold according to claim 4 or 5, characterized in that: The gas metal arc welding method has at least one of the following characteristics: (a1) The arc current used in the gas metal arc welding method is 150~190A; (a2) The voltage used in the gas metal arc welding method is 19~23V; (a3) The deposition rate of the gas metal arc welding method described above during printing is 280~370 mm / min; (a4) The heat input used in the gas metal arc welding method is 519~736 J / mm.

7. The method for preparing a water distribution manifold according to claim 5, characterized in that: The flow rate of the condensate in step S1 is 1~1.5 LPM; And / or, the flow rate of condensate in steps S2 and S3 is 1.5~2.5 LPM; And / or, in step S2, the temperature at the connection between the water distributor and the main body of the pipe is 200~280℃; And / or, in step S3, the temperature at the connection between the water tap and the main body of the pipe is 200~280℃; And / or, the pipe body needs to have its surface oxide layer removed and then be sandblasted before use; And / or, the surface roughness Ra value of the pipe body is 5~7.5μm.

8. The method for preparing a water distribution manifold according to claim 5, characterized in that: The printing path is constructed by building a model in 3D software based on the structure of the water distribution manifold, and then importing the model into the slicing system. Using the main body of the pipe as the reference plane, printing parameters with a scanning interval of 0.1~0.5mm are constructed to form a printing path for the gas metal arc welding method.

9. The method for preparing a water distribution manifold according to claim 4 or 5, characterized in that: The heat treatment involves first performing a first heat treatment at 250~350℃, then raising the temperature to 550~600℃ for a second heat treatment, followed by cooling.

10. The application of the water distribution manifold according to any one of claims 1 to 3 or the water distribution manifold prepared by the method according to any one of claims 4 to 9 in the field of liquid cooling systems or servers.

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