Welding mode of liquid cooling valve and connector piece

Abstract

The welding mode of the liquid cooling valve and the connector piece comprises the steps that laser shock treatment is conducted on to-be-welded areas of the liquid cooling valve and the connector piece, and an interlocked staggered groove structure is formed; depositing a transition film on the surface of the liquid cooling valve after laser shock treatment; after the liquid cooling valve and the connector piece are assembled, the liquid cooling valve and the connector piece are placed in an alternating magnetic field, and brazing treatment is conducted on the liquid cooling valve and the connector piece; the brazed liquid cooling valve and the brazed connector piece are cooled, and ultrasonic vibration treatment is applied in the cooling stage; the femtosecond laser is used for carrying out scanning impact on the welding seam edge of the liquid cooling valve and the connector piece to form a strengthening belt. Through the arrangement of the interlocked staggered groove structure and the transition film, brazing under the alternating magnetic field and ultrasonic vibration treatment applied in the cooling stage are combined, finally, a strengthening belt is formed on the edge of a weld joint, and the strength of the welding structure between the liquid cooling valve and the connector piece is remarkably enhanced. Therefore, the technical problem that in the prior art, the welding structure of the liquid cooling valve and the connector piece is insufficient in strength is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid cooling valve welding, and particularly to a welding method for a liquid cooling valve and a joint member. Background Art

[0002] A liquid cooling valve is a device used to control and regulate the fluid flow in a liquid cooling system. It is usually applied in liquid cooling systems, such as computer cooling, automobile engine cooling, and other industrial equipment that requires effective heat dissipation. In electronic devices, the liquid cooling valve can achieve intelligent control of the coolant to improve the heat dissipation efficiency and extend the service life of the device. The liquid cooling valve can be divided into a manual liquid cooling valve and an automatic liquid cooling valve (such as an electric valve, a pneumatic valve, etc.). The automatic liquid cooling valve can be automatically adjusted through sensors and control systems to optimize according to real-time temperature or other parameters.

[0003] In the prior art, most liquid cooling valves and joint members are brazed. As the core connection node of the cooling circuit, its welding structure needs to withstand multiple loads such as high pressure, high-frequency vibration, and temperature cycling. However, during the brazing cooling process of the liquid cooling valve and the joint member, due to the difference in the thermal expansion coefficients of the base material and the filler metal (such as the difference between aluminum / steel reaches 50%), it is easy to cause residual stress to concentrate at the interface, accelerate the generation of microcracks, and thus lead to insufficient strength of the welding structure of the liquid cooling valve and the joint member. Summary of the Invention

[0004] The purpose of the present invention is to provide a welding method for a liquid cooling valve and a joint member, which solves the technical problem of insufficient strength of the welding structure of the liquid cooling valve and the joint member in the prior art.

[0005] To achieve this purpose, the present invention adopts the following technical solutions: A welding method for a liquid cooling valve and a joint member, comprising: Step S1, performing laser shock treatment on the welding area to be welded of the liquid cooling valve and the joint member to form an interlocked staggered groove structure; Step S2, depositing a transition film on the surface of the liquid cooling valve after laser shock treatment. The transition film includes a first layer film, a second layer film, and a third layer film deposited in sequence. The first layer film is an aluminum-silicon alloy, the second layer film is an aluminum-titanium alloy, and the third layer film is a titanium-iron alloy; Step S3, after assembling the liquid cooling valve and the joint member, placing them in an alternating magnetic field, and performing brazing treatment on the liquid cooling valve and the joint member; Step S4, performing a cooling treatment on the liquid cooling valve and the joint member after brazing is completed, and applying ultrasonic vibration treatment during the cooling stage; Step S5, performing scanning shock on the weld edge of the liquid cooling valve and the joint member through femtosecond laser to form a strengthening band.

[0006] Optionally, before step S1, it further includes: A cleaning step, in which the surfaces to be welded of the liquid-cooling valve and the connector are subjected to surface cleaning treatment by an argon-oxygen mixed plasma. The volume ratio of the Ar / O2 mixed gas is 4:1, the gas flow rate is 80 - 100 sccm, and the radio frequency power is 13.56 MHz; An activation step, in which the surfaces to be welded of the liquid-cooling valve and the connector after cleaning are subjected to surface activation treatment by a nitrogen-hydrogen pulsed plasma. The volume ratio of the N2 / H2 mixed gas is 3:1, and the gas flow rate is 60 - 80 sccm; A pulsed microwave plasma is used, with a peak power of 800 - 1000 W, a pulse frequency of 100 - 200 Hz, and a pulse width of 50 - 100 μs; A pre-etching step, in which the surfaces to be welded of the liquid-cooling valve and the connector after activation treatment are pre-etched by a helium-based plasma, so that conical nanocolumns are formed on the surface of the liquid-cooling valve, and honeycomb-shaped nanopores are formed on the surface of the connector.

[0007] Optionally, the cleaning step specifically includes: In the first stage, the radio frequency power is 300 - 400 W, the pulse duty cycle is 50%, and the duration is 3 - 5 min; in the second stage, the radio frequency power is reduced to 150 - 200 W, and a continuous mode is adopted, and the proportion of O2 is increased to 30% to clean the surfaces to be welded of the liquid-cooling valve and the connector.

[0008] Optionally, the pre-etching step adopts a dual-frequency excitation mode, with a low frequency of 40 kHz and a high frequency of 13.56 MHz, and the radio frequency power is regulated in a gradient manner, specifically including: In the first stage, the etching time is 0 - 2 min, the low-frequency proportion is 70%, and the power density is 0.8 - 1.0 W / cm 2 , forming uniform etch pits with a diameter of 50 - 100 nm and a depth of 10 - 15 nm; In the second stage, the etching time is 2 - 5 min, the high-frequency proportion is increased to 60%, and the power density is 1.2 - 1.5 W / cm 2 ; The height of the nanocolumns obtained is 80 - 120 nm, the spacing between the nanocolumns is 30 - 50 nm, the pore diameter of the nanopores is 20 - 40 nm, and the depth of the nanopores is 50 - 80 nm.

[0009] Optionally, step S1 specifically includes: Step S11, configuring the working parameters of the laser shock treatment. The laser wavelength of the pulsed laser is 1064 nm, the single-pulse energy is 5 - 8 J, the pulse frequency is 20 - 50 kHz, and the spot diameter is 0.1 - 0.3 mm; the incident angle of the laser beam is 45 - 75°, and the shock pressure is controlled at 2 - 5 GPa; Step S12, under the working parameters of Step S11, perform a biaxial cross-scan on the liquid cooling valve and the joint. The angle between the first scanning direction and the second scanning direction is 60 to 90°, and the scanning path forms a grid-like groove with a width of 50 to 100 μm and a depth of 30 to 50 μm. The spacing between adjacent grooves is 100 to 200 μm, and the scanning overlap rate is 30% to 50%, so that micro-protrusion structures with a height of 10 to 20 μm are formed on the side walls of the grooves.

[0010] Optionally, Step S2 specifically includes: Step S21, deposit a first layer of film with a thickness of 10 to 15 μm on the surface of the liquid cooling valve after laser shock peening by magnetron sputtering. An aluminum-silicon alloy target is used, and the silicon content is 8 - 12 wt%; among them, the sputtering parameters are: the vacuum degree ≤ 1×10 -3 Pa, the temperature of the liquid cooling valve is 150 to 180 °C, the sputtering power is 2 to 3 kW, the argon gas flow rate is 30 to 50 sccm, and the deposition rate is 0.8 to 1.2 μm / min; Step S22, switch to an aluminum-titanium composite target with a gradient distribution of the aluminum-titanium atomic ratio from 9:1 to 1:1, and deposit a second layer of film with a thickness of 20 to 30 μm on the first layer of film; among them, the sputtering parameters are: the temperature of the liquid cooling valve is raised to 180 to 200 °C, the sputtering power is 4 - 5 kW, the argon gas flow rate is 50 - 70 sccm, and the deposition rate is 1.0 to 1.5 μm / min; Step S23, switch to a titanium-iron alloy target with an iron content of 40 - 50 wt%, and deposit a third layer of film with a thickness of 15 to 20 μm on the second layer of film to obtain a transition film; among them, the sputtering parameters are: the temperature of the liquid cooling valve is 200 °C, the sputtering power is 6 - 8 kW, the argon / nitrogen mixing ratio is 9:1, the gas flow rate is 80 sccm, and the deposition rate is 1.5 - 2.0 μm / min.

[0011] Optionally, Step S3 specifically includes: Step S31, assemble the liquid cooling valve deposited with the transition film and the joint subjected to laser shock peening into a fixture, apply an axial pre-tightening force of 2 to 4 MPa, and place it in an alternating magnetic field environment; among them, the magnetic field parameters are: the frequency is 50 to 100 Hz, the magnetic induction intensity is 0.3 to 0.5 T, and the angle between the magnetic field direction and the weld plane is 30° to 45°; Step S32, perform brazing on the liquid cooling valve and the joint with Zn-15Al filler metal; during the brazing process, the heating rate is 10 to 15 °C / min, the brazing temperature is raised to 430 to 450 °C, and it is kept warm for 8 to 10 min; Step S33, apply a stepped pressure axially during the brazing process.

[0012] Optionally, step S33 specifically includes: Step S331, in the initial stage, when the brazing temperature is between 25 and 300 °C, the applied pressure is 5 to 8 MPa; Step S332, in the main welding stage, when the brazing temperature is between 300 and 450 °C, the applied pressure is 12 to 15 MPa; Step S333, in the cooling stage, when the brazing temperature gradually decreases from 450 °C to 200 °C, the applied pressure is 3 to 5 MPa.

[0013] Optionally, step S4 specifically includes: Step S41, perform a cooling treatment on the liquid-cooled valve and the joint that have completed brazing, and synchronously apply axial ultrasonic vibration in the stage where the temperature decreases from 450 °C to 300 °C; use nitrogen jet for forced cooling, the cooling rate is 10 to 15 °C / min, the included angle between the air flow direction and the axial direction of the weld is 30° to 45°, and the air flow pressure is 0.3 to 0.5 MPa; the vibration frequency is 20 - 25 kHz, the amplitude is 10 - 15 μm, and the vibration direction is the same as the cooling air flow; Step S42, in the stage where the temperature decreases from 300 °C to 150 °C, switch to argon protection for slow cooling and apply multi-directional ultrasonic vibration, and the vibration mode switches to radial and axial composite vibration; the cooling rate is 2 to 5 °C / min, the gas flow rate is 50 to 80 sccm; the radial vibration frequency is 25 to 30 kHz, the amplitude is 5 to 10 μm; the axial vibration frequency is 15 to 20 kHz, the amplitude is 8 to 12 μm; the pulse duty cycle is 40% to 60%, and the pulse interval is 0.5 to 1 s.

[0014] Optionally, the strengthening band includes a first strengthening band and a second strengthening band, and step S5 specifically includes: Step S51, configure the working parameters of the femtosecond laser, the wavelength is 1030 nm, the single-pulse energy is 0.5 to 1.5 mJ, and the pulse width is 300 to 500 fs; the spot diameter is 20 to 50 μm, the scanning speed is 1000 to 2000 mm / s, and the incident angle of the laser beam is 60° to 75°; Step S52, perform a spiral progressive scan along the weld edge, the pitch is 50 to 100 μm, the scanning overlap rate is 20% to 40%, form a first strengthening band on one side of the liquid-cooled valve, and form a second strengthening band on one side of the joint.

[0015] Compared with the prior art, the present invention has the following beneficial effects: A welding method for a liquid cooling valve and a joint provided by the present invention. In step S1, an interlocked staggered groove structure is formed on the surfaces of the liquid cooling valve and the joint, which improves the mechanical biting force and enables the subsequent welded joint to have a stronger interfacial bonding strength; in step S2, a transition film is deposited on the surface of the liquid cooling valve to relieve the interfacial damage caused by thermal stress and improve the reliability and fatigue resistance of the overall welding interface; in step S3, the alternating magnetic field promotes the fluidity and diffusivity of the filler metal, improves the weld density, and reduces pore defects; in step S4, ultrasonic vibration is applied during the cooling process to effectively promote the microscopic rearrangement and densification of the filler metal and the interfacial structure, inhibit the concentration of thermal stress and reduce the residual stress, thereby enhancing the fatigue life and reliability of the welded joint; in step S5, strengthening bands are respectively formed on the liquid cooling valve side and the joint side, which can effectively block the crack propagation under thermo-mechanical loads and significantly improve the crack resistance, fatigue resistance and corrosion resistance of the welding edge area. Therefore, the present invention solves the technical problem of insufficient welding structural strength between the liquid cooling valve and the joint in the prior art. Brief Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] The structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those who are familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have technical substance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed by the present invention.

[0018] Figure 1 It is a flowchart of a welding method for a liquid cooling valve and a joint provided by an embodiment of the present invention. Detailed Embodiments

[0019] In order to make the invention purposes, features and advantages of the present invention more obvious and understandable, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the following described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0020] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component present at the same time.

[0021] The technical solution of the present invention will be further described below with reference to the drawings and through specific embodiments.

[0022] The embodiment of the present invention provides a welding method for a liquid cooling valve and a joint piece, as Figure 1 shown, including: Step S1, performing laser shock treatment on the welding area to be welded of the liquid cooling valve and the joint piece to form an interlocked staggered groove structure. In this embodiment, the welding area to be welded of the liquid cooling valve and the joint piece is subjected to laser shock treatment by a pulsed laser. The pulsed laser is a well-known technology in the art and will not be elaborated here.

[0023] In one embodiment, step S1 specifically includes: Step S11, configuring the working parameters of the laser shock treatment. The laser wavelength of the pulsed laser is 1064 nm, the single pulse energy is 5 - 8 J, the pulse frequency is 20 - 50 kHz, and the spot diameter is 0.1 - 0.3 mm; the incident angle of the laser beam is 45 - 75°, and the impact pressure is controlled at 2 - 5 GPa; Step S12, under the working parameters of step S11, performing a two-axis cross scan on the liquid cooling valve and the joint piece. The angle between the first scan direction and the second scan direction is 60 - 90°. The scan path forms a grid-like groove with a width of 50 - 100 μm and a depth of 30 - 50 μm. The distance between adjacent grooves is 100 - 200 μm, and the scan overlap rate is 30% - 50%, so that a micro-protrusion structure with a height of 10 - 20 μm is formed on the groove side wall.

[0024] It should be noted that the grid-like grooves formed by laser shock peening not only increase the contact area between the liquid cooling valve and the joint, but also enhance the mechanical connection force between the surfaces through the interlocking staggered structure, providing better interfacial conditions for the welding in subsequent step S3 and contributing to achieving a firm bond. Since the spacing between adjacent grooves is 100 - 200 μm and the scanning overlap rate is 30% - 50%, it helps to avoid the uneven distribution of material stress during welding, reduces the thermal stress caused by the difference in thermal expansion, and reduces the risk of welding cracks. Both the groove structure and the micro-protrusion structure effectively enhance the contact performance of the material, improve the adhesion of the solder, and thus improve the welding quality. During the soldering process of subsequent step S3, the groove structure provides additional space to help the solder distribute evenly and form a stronger metallurgical bond after welding. During the cooling process of subsequent step S4, the structure formed by laser shock peening helps to disperse the thermal stress and reduce the thermal deformation caused by the temperature difference.

[0025] In one embodiment, before step S1, it further includes: A cleaning step, where the surfaces to be welded of the liquid cooling valve and the joint are subjected to surface cleaning treatment by argon-oxygen mixed plasma. The volume ratio of the Ar / O2 mixed gas is 4:1, the gas flow rate is 80 - 100 sccm, and the radio frequency power is 13.56 MHz; An activation step, where the surfaces to be welded of the liquid cooling valve and the joint after cleaning are subjected to surface activation treatment by nitrogen-hydrogen pulsed plasma. The volume ratio of the N2 / H2 mixed gas is 3:1, and the gas flow rate is 60 - 80 sccm; A pulsed microwave plasma is used, with a peak power of 800 - 1000 W, a pulse frequency of 100 - 200 Hz, and a pulse width of 50 - 100 μs; A pre-etching step, where the surfaces to be welded of the liquid cooling valve and the joint after activation treatment are pre-etched by helium-based plasma, forming conical nanocolumns on the surface of the liquid cooling valve and honeycomb-like nanopores on the surface of the joint. In this embodiment, the cleaning step, the activation step, and the pre-etching step all use common plasma equipment in the art and will not be elaborated here. The nanostructures formed by pre-etching significantly increase the surface roughness, thereby increasing the contact area between the liquid cooling valve and the joint, providing an optimized surface state for the laser shock peening in step S1, making the groove structure more uniform and the micro-protrusions more stable, and also providing better mechanical bonding conditions for subsequent welding and film deposition. By increasing the surface roughness and improving the interface structure, the thermal stress formed during the welding process of subsequent step S3 is dispersed, reducing the generation of microcracks after welding.

[0026] It should be noted that through cleaning, activation, and pre-etching treatments, it is ensured that the welding surface is free of impurities, has high activity, and has an optimized surface structure, which can effectively reduce welding defects (such as pores, cracks, etc.), making the deposition quality of the transition film higher, enabling stronger interfacial bonding, and enhancing the welding strength between the liquid cooling valve and the joint. By increasing the surface roughness and improving the interfacial structure, the thermal stress formed during the welding process is dispersed, reducing the generation probability of microcracks after welding. Therefore, the cleaning, activation, and pre-etching steps provide an important prerequisite for subsequent processes such as laser shock treatment, brazing, and the formation of strengthening bands, ensuring the smooth progress of the entire welding process and the high quality of the final welded joint.

[0027] In one embodiment, the cleaning step specifically includes: The radio frequency power in the first stage is 300 - 400 W, the pulse duty cycle is 50%, and the duration is 3 - 5 min; in the second stage, the radio frequency power is reduced to 150 - 200 W, continuous mode is adopted, and the proportion of O2 is increased to 30% to clean the welding surfaces of the liquid cooling valve and the joint.

[0028] It should be noted that during the cleaning process, the physical bombardment of argon and the chemical reaction of oxygen can effectively remove impurities such as oil stains and oxides on the surfaces of the liquid cooling valve and the joint, laying a foundation for subsequent surface activation and pre-etching steps, improving the surface cleanliness, and being beneficial to the interfacial bonding during subsequent brazing and film deposition processes. The plasma of nitrogen and hydrogen can excite the surfaces of the liquid cooling valve and the joint, improve their chemical activity, increase the surface energy, making the surface more likely to bond with subsequent materials (such as the transition film). The activation treatment makes the surface atoms or molecules in a higher energy state, which helps the adhesion of the transition film in subsequent step S2 during subsequent deposition and improves the film quality.

[0029] In one embodiment, the pre-etching step adopts a dual-frequency excitation mode, with the low frequency being 40 kHz and the high frequency being 13.56 MHz, and the radio frequency power is regulated in a gradient manner, specifically including: The etching time in the first stage is 0 - 2 min, the low-frequency proportion is 70%, and the power density is 0.8 - 1.0 W / cm 2 , forming uniform etch pits with a diameter of 50 - 100 nm and a depth of 10 - 15 nm; The etching time in the second stage is 2 - 5 min, the high-frequency proportion is increased to 60%, and the power density is 1.2 - 1.5 W / cm 2 ; the height of the nanocolumns obtained is 80 - 120 nm, the spacing between the nanocolumns is 30 - 50 nm, the pore diameter of the nanopores is 20 - 40 nm, and the depth of the nanopores is 50 - 80 nm.

[0030] It should be noted that through the regulation of the dual-frequency excitation mode, a uniform pit structure is first formed in the low-frequency stage to provide a uniform surface roughness; while in the high-frequency stage, finer nanopillars and nanopores are generated, greatly increasing the surface roughness and surface area, providing ideal "anchoring points" for the film deposition in subsequent step S2 and the welding process in step S3. The formation of nanostructures (especially nanopillars and nanopores) provides more microscopic contact points, which can effectively increase the mechanical bonding force of the welding interface and contribute to the wetting and diffusion of the filler metal during the brazing process in step S3, improving the welding quality. Through the application of the pre-etching step, not only can the surface properties be improved, but also the surface topography can be effectively controlled, the residual stress can be reduced, and the stability and durability of the interface can be enhanced.

[0031] In summary, through the dual-frequency excitation mode, the pre-etching step effectively adjusts the surface structure by using the combination of low frequency and high frequency, enhancing the bonding force and welding performance between the liquid cooling valve and the joint. The nanoscale surface features provide a solid foundation for the subsequent film deposition and welding processes and can optimize the performance of the welding interface.

[0032] In step S2, a transition film is deposited on the surface of the liquid cooling valve after laser shock peening. The transition film includes a first layer film, a second layer film, and a third layer film deposited in sequence. The first layer film is an aluminum-silicon alloy, the second layer film is an aluminum-titanium alloy, and the third layer film is a titanium-iron alloy. In this embodiment, the transition film is deposited on the surface of the liquid cooling valve after laser shock peening by a magnetron sputtering coater well-known in the art, which will not be elaborated here.

[0033] In one embodiment, step S2 specifically includes: In step S21, a first layer film with a thickness of 10 - 15 μm is deposited on the surface of the liquid cooling valve after laser shock peening by a magnetron sputtering process, using an aluminum-silicon alloy target with a silicon content of 8 - 12 wt%. Among them, the sputtering parameters are: the vacuum degree ≤ 1×10 -3 Pa, the temperature of the liquid cooling valve is 150 - 180 °C, the sputtering power is 2 - 3 kW, the argon gas flow rate is 30 - 50 sccm, and the deposition rate is 0.8 - 1.2 μm / min; in this embodiment, the first layer of aluminum-silicon alloy film can improve the surface adhesion and enhance the oxidation resistance of the welding interface at the same time; the deposition of the aluminum-silicon alloy can provide good thermal conductivity, helping to relieve the thermal expansion difference between different materials.

[0034] Step S22: Switch to an aluminum-titanium composite target with a gradient distribution of aluminum-titanium atomic ratio from 9:1 to 1:1, and deposit a second layer with a thickness of 20 - 30 μm on the first layer; among them, the sputtering parameters are: the temperature of the liquid cooling valve rises to 180 - 200 °C, the sputtering power is 4 - 5 kW, the argon gas flow rate is 50 - 70 sccm, and the deposition rate is 1.0 - 1.5 μm / min; in this embodiment, the aluminum-titanium alloy of the second aluminum-titanium alloy film has excellent high-temperature resistance and strength. As an intermediate layer, it can effectively connect the aluminum-silicon alloy layer and the titanium-iron alloy layer, playing a transitional role and improving the mechanical properties of the welding area.

[0035] Step S23: Switch to a titanium-iron alloy target with an iron content of 40 - 50 wt%, and deposit a third layer with a thickness of 15 - 20 μm on the second layer to obtain a transition film; among them, the sputtering parameters are: the temperature of the liquid cooling valve is 200 °C, the sputtering power is 6 - 8 kW, the argon / nitrogen mixing ratio is 9:1, the gas flow rate is 80 sccm, and the deposition rate is 1.5 - 2.0 μm / min. In this embodiment, the high wear resistance and corrosion resistance of the titanium-iron alloy of the third titanium-iron alloy film enable this layer of film to provide strong durability and enhance the stability of the welded joint, especially in the performance under temperature fluctuations and vibrations.

[0036] It should be noted that by using the magnetron sputtering process for film deposition, it can ensure that the film layer is uniform, dense, and has good adhesion, avoiding the film layer peeling problem that may occur in traditional welding methods. This transition film helps to reduce the thermal expansion difference between different materials, improve the bonding force between the liquid cooling valve and the joint piece, and enhance the stability and strength of the welded joint. The combination of multiple layers of films not only provides stronger interfacial bonding ability but also improves the fatigue resistance and corrosion resistance of the joint after welding. The deposited transition film layer can effectively reduce the residual stress generated due to temperature difference changes, avoid cracks or fractures caused by the difference in thermal expansion coefficients during the welding process, and improve the long-term use stability of the liquid cooling valve and the joint piece. The deposited transition film provides a uniform substrate, which helps the solder to flow and be evenly distributed during the brazing process in subsequent step S3, enhancing the chemical and mechanical bonding forces between the brazing material and the base material, and ensuring the high quality and long-term stability of the brazed joint. During the cooling and strengthening stages (such as ultrasonic vibration cooling and femtosecond laser strengthening band treatment), the deposition of the transition film provides stable surface conditions for steps S4 and S5, ensuring the integrity and firmness of the joint structure during intense thermal cycles.

[0037] Step S3: After assembling the liquid cooling valve and the connector, place them in an alternating magnetic field and perform brazing on the liquid cooling valve and the connector. In this embodiment, a brazing device is used for brazing. The brazing device includes a temperature control system, a pressure application system, and an alternating magnetic field device. The liquid cooling valve and the connector are clamped and assembled by a brazing fixture. The alternating magnetic field generator provides an alternating magnetic field. The brazing fixture and the alternating magnetic field generator are well-known technologies in the art and will not be elaborated here.

[0038] In one embodiment, step S3 specifically includes: Step S31: Assemble the liquid cooling valve with a deposited transition film and the connector treated by laser shock peening into a fixture, apply an axial pre-tightening force of 2 - 4 MPa, and place it in an alternating magnetic field environment. Among them, the magnetic field parameters are: the frequency is 50 - 100 Hz, the magnetic induction intensity is 0.3 - 0.5 T, and the included angle between the magnetic field direction and the weld plane is 30° - 45°. In this embodiment, the alternating magnetic field helps to enhance heat conduction and the fluidity of the filler metal during brazing, improve the wettability of the filler metal, and make the welded joint more dense. By applying the axial pre-tightening force, the stress caused by uneven thermal expansion during welding can be reduced, and the structure of the welded joint can be optimized.

[0039] Step S32: Use Zn-15Al filler metal to perform brazing on the liquid cooling valve and the connector. During brazing, the heating rate is 10 - 15 °C / min, the brazing temperature is raised to 430 - 450 °C, and it is held for 8 - 10 min. In this embodiment, the Zn-15Al filler metal can provide good fluidity and wettability, ensuring that the filler metal can be evenly distributed at the contact interface between the liquid cooling valve and the connector, forming a firm bond. By controlling the brazing temperature and the holding time, the structural stability of the brazed joint can be ensured, and at the same time, material deformation or melting caused by too high temperature can be avoided.

[0040] Step S33: Apply a stepped pressure axially during brazing. In this embodiment, the pressure application device is a well-known technology in the art and will not be elaborated here. By applying the stepped pressure, the best sealing performance of the welded joint at different temperatures can be ensured, and the thermal stress caused by temperature difference changes can be reduced. Applying a lower pressure during the cooling stage helps to avoid cracks or uneven joints after welding.

[0041] It should be noted that by performing brazing treatment in an alternating magnetic field, combined with axial pre-tightening force and stepped pressure control, the quality of the welded joint can be effectively improved, cracks caused by thermal stress can be reduced, and the reliability and durability of the welded joint can be ensured. Through the application of an alternating magnetic field generator and a brazing fixture, a stable physical environment is provided for the subsequent brazing process, enabling the welded joint to have good mechanical properties. The alternating magnetic field promotes the uniform distribution and flow of the filler metal, enhancing the sealing performance and firmness of the welded joint. During the brazing process, the alternating magnetic field changes the microstructure of the material, enhancing the metallurgical bonding between the materials and effectively improving the overall performance of the welded joint.

[0042] In one embodiment, step S33 specifically includes: Step S331, in the initial stage, when the brazing temperature is between 25 and 300 °C, the applied pressure is 5 to 8 MPa; in this embodiment, in this stage, by applying a preliminary pressure, the preliminary contact between the liquid cooling valve and the joint piece is ensured, while avoiding the filler metal from failing to effectively wet and spread due to too low temperature.

[0043] Step S332, in the main welding stage, when the brazing temperature is between 300 and 450 °C, the applied pressure is 12 to 15 MPa; in this embodiment, the temperature in the main welding stage rises to the brazing temperature range, and a higher pressure is applied to promote the full flow and uniform diffusion of the filler metal, ensuring the formation of a high-quality welded joint.

[0044] Step S333, in the cooling stage, when the brazing temperature gradually decreases from 450 °C to 200 °C, the applied pressure is 3 to 5 MPa. In this embodiment, when the temperature gradually decreases, by applying a lower pressure, it helps to reduce thermal stress and prevent cracks or other defects caused by a sudden temperature drop.

[0045] It should be noted that the initial pressure in step S331 helps to ensure the initial butt joint between materials in the low-temperature stage of the brazing process, reduce the interface non-uniformity caused by thermal expansion differences, ensure the alignment of the initial materials, and prevent premature loss or insufficiency of the brazing filler metal. The higher pressure and temperature conditions in step S332 can promote the wetting and spreading of the brazing filler metal, enable the brazing filler metal to uniformly cover the contact surface, and improve the metallurgical bonding strength of the welded joint; the pressure in this stage can also avoid the joint deformation caused by thermal expansion differences and ensure the shape stability of the welded joint. During the cooling process in step S333, the reduced pressure helps to relieve the residual stress during cooling and prevent the material deformation caused by too rapid cooling; through the gradual reduction of the pressure, it can be ensured that the welded joint will not crack due to stress concentration during the cooling process. By applying different pressures, especially applying a lower pressure in the cooling stage, excessive residual stress is avoided, the risk of cracks is reduced, which is particularly important for the subsequent cooling treatment in step S4 and helps to improve the stability of the welded joint. By combining the applied pressure and the brazing temperature, the fluidity of the brazing filler metal and the good bonding of the contact interface are ensured, providing a solid foundation for the subsequent cooling in step S4 and the strengthening treatment in step S5.

[0046] Step S4: Cool the brazed liquid-cooled valve and joint piece, and apply ultrasonic vibration treatment during the cooling stage. Specifically, the cooling device includes a cooling system for nitrogen and argon injection, which can precisely control the gas flow pressure and the cooling rate. Ultrasonic vibration device: During the cooling stage, by applying axial and multi-directional ultrasonic vibrations, the vibration frequency and amplitude of the device can be precisely controlled to ensure the strengthening effect of the welded joint during the cooling process. The cooling device and the ultrasonic vibration device are both well-known technologies and will not be elaborated here.

[0047] It should be noted that through the combination of cooling and ultrasonic vibration, the cooling rate can be effectively controlled, avoiding stress concentration caused by too rapid cooling, thereby reducing the generation of cracks. Ultrasonic vibration helps to release the thermal stress generated during the cooling process and improve the toughness of the welded joint.

[0048] In one embodiment, step S4 specifically includes: Step S41: Cool the brazed liquid-cooled valve and joint piece, and synchronously apply axial ultrasonic vibration during the stage when the temperature drops from 450°C to 300°C; use nitrogen injection for forced cooling, with a cooling rate of 10 - 15°C / min, the included angle between the gas flow direction and the axial direction of the weld seam is 30° - 45°, and the gas flow pressure is 0.3 - 0.5 MPa; the vibration frequency is 20 - 25 kHz, the amplitude is 10 - 15 μm, and the vibration direction is the same as the cooling gas flow direction; in this embodiment, nitrogen is used as the cooling gas, which has a higher heat absorption capacity compared to other gases, helping to ensure that the cooling process is uniform and controllable.

[0049] In step S42, during the stage when the temperature decreases from 300 °C to 150 °C, switch to slow cooling under argon protection and apply multi-directional ultrasonic vibration. The vibration mode is switched to radial and axial composite vibration; the cooling rate is 2 - 5 °C / min, the gas flow rate is 50 - 80 sccm; the radial vibration frequency is 25 - 30 kHz, the amplitude is 5 - 10 μm; the axial vibration frequency is 15 - 20 kHz, the amplitude is 8 - 12 μm; the pulse duty cycle is 40% - 60%, and the pulse interval is 0.5 - 1 s.

[0050] It should be noted that in step S41, by nitrogen injection, the temperature of the liquid cooling valve and the joint can be rapidly reduced, thereby accelerating the cooling process and reducing the residual thermal stress in the welded joint; by increasing high-frequency vibration, it helps the release of bubbles during the cooling process and the densification of the welded joint, further optimizing the cooling process, reducing the generation of microcracks, and increasing the densification of the welded joint. In step S42, the slow cooling process can provide a more stable cooling environment through argon protection cooling, avoiding material stress concentration and possible cracks caused by too fast cooling; through multi-directional ultrasonic vibration, it not only helps to cool evenly, but also can release stress in all directions of the welded joint, further improving the strength and stability of the welded joint; by applying composite vibration, it can not only strengthen the internal structure of the welded joint, but also promote the rearrangement of microcrystals, improving the fatigue resistance of the joint. The formation of the femtosecond laser scanning strengthening band in the subsequent step S5 depends on precise cooling control and the stability of the welded joint. The ultrasonic vibration applied during the cooling process helps to improve the microstructure of the welding area, making it more suitable for subsequent laser strengthening treatment, thereby enhancing the overall performance of the welded joint.

[0051] Step S5, perform scanning impact on the weld edge of the liquid cooling valve and the joint by femtosecond laser to form a strengthening band. In this embodiment, a femtosecond laser device is used to perform laser scanning treatment on the weld edge of the liquid cooling valve and the joint. The femtosecond laser device includes a femtosecond laser and a scanning system. The femtosecond laser device is a well-known technology in the art and will not be elaborated here.

[0052] In one embodiment, the strengthening band includes a first strengthening band and a second strengthening band. Step S5 specifically includes: Step S51, configure the working parameters of the femtosecond laser, the wavelength is 1030 nm, the single pulse energy is 0.5 - 1.5 mJ, the pulse width is 300 - 500 fs; the spot diameter is 20 - 50 μm, the scanning speed is 1000 - 2000 mm / s, and the incident angle of the laser beam is 60° - 75°; Step S52, perform spiral progressive scanning along the weld edge, the pitch is 50 - 100 μm, the scanning overlap rate is 20% - 40%, form a first strengthening band on one side of the liquid cooling valve, and form a second strengthening band on one side of the joint.

[0053] It should be noted that in step S51, the working parameter configuration of the femtosecond laser helps to precisely control the impact intensity and action depth of the laser, ensuring that the strengthening zone at the weld edge can generate an ideal microstructure without damaging the welding area; by using a femtosecond laser with a short pulse width (300 - 500 fs), thermal diffusion can be effectively avoided, the processing accuracy of the local area can be improved, the microstructure of the welded joint can be optimized, and the anti-fatigue performance and crack resistance of the welded joint can be enhanced. In step S52, through spiral progressive scanning, the uniform distribution of the laser at the weld edge is ensured, enabling the strengthening zone to be effectively formed in the interface area between the liquid cooling valve and the joint component; by adjusting the pitch and scanning overlap rate, the thickness and density of the strengthening zone are controlled, thereby achieving the effect of optimizing the microstructure and mechanical properties of the welded joint. The strengthening zone formed by the scanning impact of the femtosecond laser improves the anti-fatigue property and crack propagation resistance of the weld edge, ensuring that the liquid cooling valve and the joint component can work stably for a long time under harsh conditions such as high pressure, high temperature, and vibration. The formation of the strengthening zone optimizes the microstructure of the welded joint, improves the toughness of the welding area, and enhances the comprehensive mechanical properties of the welded joint.

[0054] In summary, through the precise control of the femtosecond laser and spiral progressive scanning, a strengthening zone is formed at the weld edge, providing additional strength and toughness to the welded joint, not only optimizing the welding quality of the liquid cooling valve and the joint component, but also enhancing the long-term stability and reliability of the welded joint.

[0055] Working principle: A welding method for a liquid cooling valve and a joint component provided by the present invention. In step S1, an interlocked staggered groove structure is formed on the surfaces of the liquid cooling valve and the joint component, improving the mechanical bite force and enabling the subsequent welded joint to have a stronger interface bonding strength; in step S2, a transition film is deposited on the surface of the liquid cooling valve to relieve interface damage caused by thermal stress and improve the reliability and fatigue resistance of the overall welding interface; in step S3, the alternating magnetic field promotes the fluidity and diffusivity of the filler metal, improves the weld compactness, and reduces pore defects; in step S4, ultrasonic vibration is applied during the cooling process to effectively promote the microscopic rearrangement and densification of the filler metal and the interface structure, inhibit the concentration of thermal stress and reduce the residual stress, thereby enhancing the fatigue life and reliability of the welded joint; in step S5, strengthening zones are respectively formed on the liquid cooling valve side and the joint component side, which can effectively block crack propagation under thermo-mechanical loads, significantly improving the crack resistance, anti-fatigue performance, and corrosion resistance of the welding edge area. Therefore, the present invention solves the technical problem of insufficient welding structure strength of the liquid cooling valve and the joint component in the prior art.

[0056] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A welding method for a liquid-cooled valve and a connector, characterized in that Including: Step S1: Conduct laser shock treatment on the welding area of the liquid cooling valve and the joint to form an interlocked staggered groove structure; Step S2: Deposit a transition film on the surface of the liquid cooling valve after laser shock treatment. The transition film includes a first layer film, a second layer film, and a third layer film deposited in sequence. The first layer film is an aluminum-silicon alloy, the second layer film is an aluminum-titanium alloy, and the third layer film is a titanium-iron alloy; Step S3: After assembling the liquid cooling valve and the joint, place them in an alternating magnetic field and perform brazing treatment on the liquid cooling valve and the joint; Step S4: Cool the liquid cooling valve and the joint after brazing and apply ultrasonic vibration treatment during the cooling stage; Step S5: Scan and impact the weld edge of the liquid cooling valve and the joint with femtosecond laser to form a strengthening band.

2. The welding method of the liquid cooling valve and the joint according to claim 1, characterized in that Before step S1, it also includes: Cleaning step: Perform surface cleaning treatment on the welding surfaces of the liquid cooling valve and the joint through argon-oxygen mixed plasma. Introduce an Ar / O2 mixed gas with a volume ratio of 4:1, the gas flow rate is 80~100 sccm, and the radio frequency power is 13.56 MHz; Activation step: Perform surface activation treatment on the welding surfaces of the liquid cooling valve and the joint after cleaning through nitrogen-hydrogen pulsed plasma. Introduce an N2 / H2 mixed gas with a volume ratio of 3:1, the gas flow rate is 60~80 sccm; Use pulsed microwave plasma, the peak power is 800~1000 W, the pulse frequency is 100~200 Hz, and the pulse width is 50~100 μs; Pre-etching step: Pre-etch the welding surfaces of the liquid cooling valve and the joint after activation treatment through helium-based plasma to form conical nanocolumns on the surface of the liquid cooling valve and honeycomb-like nanopores on the surface of the joint.

3. The welding method of the liquid-cooling valve and the joint according to claim 2, characterized in that, The cleaning step specifically includes: In the first stage, the radio frequency power is 300~400 W, the pulse duty cycle is 50%, and the duration is 3~5 min; In the second stage, the radio frequency power drops to 150~200 W, and the continuous mode is adopted. The proportion of O2 is increased to 30% to clean the welding surfaces of the liquid cooling valve and the joint.

4. The welding method of the liquid-cooling valve and the connector according to claim 2, characterized in that, The pre-etching step adopts a dual-frequency excitation mode, the low frequency is 40 kHz, the high frequency is 13.56 MHz, and the radio frequency power is adjusted in a gradient manner. Specifically, it includes: The etching time in the first stage is 0 - 2 min, the low-frequency ratio is 70%, and the power density is 0.8 - 1.0 W / cm 2 , forming uniform etch pits with a diameter of 50 - 100 nm and a depth of 10 - 15 nm; The etching time in the second stage is 2 - 5 min, the high-frequency ratio increases to 60%, and the power density is 1.2 - 1.5 W / cm 2 ; the height of the nanorods obtained is 80 - 120 nm, the spacing between the nanorods is 30 - 50 nm, the pore diameter of the nanopores is 20 - 40 nm, and the depth of the nanopores is 50 - 80 nm.

5. The welding method of the liquid cooling valve and the joint according to any one of claims 1 to 4, characterized in that, Step S1 specifically includes: Step S11: Configure the working parameters of laser shock treatment. The laser wavelength of the pulsed laser is 1064 nm, the single pulse energy is 5~8 J, the pulse frequency is 20~50 kHz, and the spot diameter is 0.1~0.3 mm; The incident angle of the laser beam is 45~75°, and the impact pressure is controlled at 2~5 GPa; Step S12: Under the working parameters of Step S11, perform a two-axis cross-scan on the liquid-cooling valve and the connector. The angle between the first scanning direction and the second scanning direction is 60 - 90°, and the scanning path forms a grid-like groove with a width of 50 - 100 μm, a depth of 30 - 50 μm, the distance between adjacent grooves is 100 - 200 μm, and the scanning overlap rate is 30% - 50%, so that micro-protrusion structures with a size of 10 - 20 μm are formed on the side walls of the grooves.

6. The welding method of the liquid-cooled valve and the joint according to any one of claims 1 to 4, characterized in that, The specific steps of Step S2 include: Step S21, deposit a first layer of film with a thickness of 10 - 15 μm on the surface of the liquid-cooled valve after laser shock peening by magnetron sputtering process, using an aluminum-silicon alloy target with a silicon content of 8 - 12 wt%; wherein, the sputtering parameters are: the vacuum degree ≤ 1×10 -3 Pa, the temperature of the liquid-cooled valve is 150 - 180 °C, the sputtering power is 2 - 3 kW, the argon gas flow rate is 30 - 50 sccm, and the deposition rate is 0.8 - 1.2 μm / min; Step S22: Switch to an aluminum-titanium composite target with a gradient distribution of aluminum-titanium atomic ratio from 9:1 to 1:1, and deposit a second layer of film with a thickness of 20 - 30 μm on the first layer of film. Among them, the sputtering parameters are: the temperature of the liquid-cooling valve rises to 180 - 200 °C, the sputtering power is 4 - 5 kW, the argon gas flow rate is 50 - 70 sccm, and the deposition rate is 1.0 - 1.5 μm / min. Step S23: Switch to a titanium-iron alloy target with an iron content of 40 - 50 wt%, and deposit a third layer of film with a thickness of 15 - 20 μm on the second layer of film to obtain a transition film. Among them, the sputtering parameters are: the temperature of the liquid-cooling valve is 200 °C, the sputtering power is 6 - 8 kW, the argon / nitrogen mixing ratio is 9:1, the gas flow rate is 80 sccm, and the deposition rate is 1.5 - 2.0 μm / min.

7. The welding method of the liquid cooling valve and the joint according to any one of claims 1 to 4, characterized in that, The specific steps of Step S3 include: Step S31: Assemble the liquid-cooling valve deposited with the transition film and the connector processed by laser shock into a fixture, apply an axial pre-tightening force of 2 - 4 MPa, and place it in an alternating magnetic field environment. Among them, the magnetic field parameters are: the frequency is 50 - 100 Hz, the magnetic induction intensity is 0.3 - 0.5 T, and the angle between the magnetic field direction and the weld plane is 30° - 45°. Step S32: Use Zn-15Al solder to perform brazing on the liquid-cooling valve and the connector. During the brazing process, the heating rate is 10 - 15 °C / min, the brazing temperature rises to 430 - 450 °C, and keep it warm for 8 - 10 min. Step S33: Apply a stepped pressure axially during the brazing process.

8. The welding method of the liquid-cooled valve and the joint according to claim 7, characterized in that, The specific steps of Step S33 include: Step S331: In the initial stage, when the brazing temperature is between 25 - 300 °C, apply a pressure of 5 - 8 MPa. Step S332: In the main welding stage, when the brazing temperature is between 300 - 450 °C, apply a pressure of 12 - 15 MPa. Step S333: In the cooling stage, when the brazing temperature gradually decreases from 450 °C to 200 °C, apply a pressure of 3 - 5 MPa.

9. The welding method of the liquid cooling valve and the joint according to any one of claims 1 to 4, characterized in that, The specific steps of Step S4 include: Step S41: Cool the liquid-cooling valve and the connector that have completed brazing, and synchronously apply axial ultrasonic vibration during the stage when the temperature decreases from 450 °C to 300 °C. Use nitrogen jet for forced cooling, the cooling rate is 10 - 15 °C / min, the angle between the air flow direction and the weld axis is 30° - 45°, the air flow pressure is 0.3 - 0.5 MPa; the vibration frequency is 20 - 25 kHz, the amplitude is 10 - 15 μm, and the vibration direction is the same as the cooling air flow direction. Step S42: During the stage when the temperature is reduced from 300 °C to 150 °C, switch to slow cooling under argon protection and apply multi-directional ultrasonic vibration. The vibration mode is switched to radial and axial composite vibration; the cooling rate is 2 - 5 °C / min, and the gas flow rate is 50 - 80 sccm; the radial vibration frequency is 25 - 30 kHz, and the amplitude is 5 - 10 μm; the axial vibration frequency is 15 - 20 kHz, and the amplitude is 8 - 12 μm; the pulse duty cycle is 40% - 60%, and the pulse interval is 0.5 - 1 s.

10. The welding method of the liquid cooling valve and the joint according to any one of claims 1 to 4, characterized in that, The strengthening band includes a first strengthening band and a second strengthening band. The specific steps of step S5 are as follows: Step S51: Configure the working parameters of the femtosecond laser. The laser wavelength is 1030 nm, the single-pulse energy is 0.5 - 1.5 mJ, and the pulse width is 300 - 500 fs; the spot diameter is 20 - 50 μm, the scanning speed is 1000 - 2000 mm / s, and the incident angle of the laser beam is 60° - 75°; Step S52: Perform spiral progressive scanning along the weld edge of the liquid cooling valve and the joint. A first strengthening band is formed on one side of the liquid cooling valve, and a second strengthening band is formed on one side of the joint; the pitch is 50 - 100 μm, and the scanning overlap rate is 20% - 40%.

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