Laser welding tool and welding method for thin-wall titanium alloy runner plate

Abstract

The invention belongs to the technical field of welding, and provides a laser welding tool and method for a thin-wall titanium alloy runner plate. A small-diameter welding wire is adopted, the laser power is adjusted, protective gas purging is started, and laser welding is conducted in the anticlockwise direction from the left lower portion; in the welding process, active cooling is carried out at the same time until welding is completed; after welding is completed, the fixing module is detached; the active cooling specifically comprises the steps that absolute ethyl alcohol is sprayed on the welded surface, after absolute ethyl alcohol on the surface of the cold plate (3) to be welded volatilizes completely and ventilation is kept for 2 min, protective gas is started again for purging for 10 s, and one-time active cooling is completed. The method is used for solving the problem that a laser welding method in the prior art easily causes heat accumulation deformation of the titanium alloy sheet, so that the welding precision of the sheet is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of welding, and particularly relates to a laser welding tooling and a welding method for a thin-walled titanium alloy flow channel plate. Background Art

[0002] With the gradually increasing heat dissipation requirements of precision electronic devices, currently, while the metal heat dissipation plate has high-efficiency heat exchange, it also needs to play a structural support role. Its complex working environment has extremely demanding requirements for its materials. Titanium and titanium alloys have characteristics such as low density, high specific strength, and good corrosion resistance. Therefore, they have high application value in the heat dissipation system of precision electronic devices and thus have high application value in the manufacturing of fuel cell bipolar plates.

[0003] However, currently, the mainstream titanium alloy liquid cooling plates are generally manufactured by diffusion welding of two ultra-thin flow channel plates with a thickness of 1.5 mm. When welding with structural components, certain connection strength and corrosion resistance are required. The commonly used laser welding method is extremely likely to cause the problem of thermal accumulation deformation of titanium alloy thin plates, and the deformation amount can reach 0.4 mm, seriously affecting the manufacturing precision of products. Since there are many factors leading to the thermal accumulation of titanium alloy thin plates, it is necessary to target and eliminate the thermal accumulation factors one by one to ensure the welding precision of thin plates. Summary of the Invention

[0004] The present invention provides a laser welding tooling for a thin-walled titanium alloy flow channel plate, which adopts a three-section detachable structure, not only ensuring the restraint of the cold plate to be welded throughout the welding process, but also ensuring the unobstructed flow of the shielding gas during the entire welding process.

[0005] The present invention also provides a laser welding method for a thin-walled titanium alloy flow channel plate to solve the problem of thermal accumulation deformation of titanium alloy thin plates easily caused by the existing laser welding method, so as to ensure the welding precision of thin plates.

[0006] To solve the above technical problems, the present invention provides a laser welding tooling for a thin-walled titanium alloy flow channel plate. The laser welding tooling includes an outer frame 1, a plurality of fixing modules 2, a pressing plate 3, a bottom plate 4, and a cold plate 5 to be welded. A groove 1-1 is opened at the upper end of the outer frame 1. The bottom plate 4 is installed in the groove 1-1. The cold plate 5 to be welded is pressed onto the bottom plate 4. The pressing plate 3 is placed on the bottom plate 4. The area of the pressing plate 3 is smaller than that of the cold plate 5 to be welded. Each side length of the pressing plate 3 is 0.1-0.3 mm away from the weld of the cold plate 5 to be welded. The superposed height of the bottom plate 4 and the pressing plate 3 embedded with the cold plate 5 to be welded is less than or equal to the height of the wall of the groove 1-1. The plurality of fixing modules 2 cooperate with the outer frame 1 to clamp the bottom plate 4 embedded with the cold plate 5 by the pressing plate 3, maintaining pressure during the laser welding process and realizing unobstructed flow of the shielding gas during the entire welding process.

[0007] Further, positioning holes 1-2 are provided on the outer frame 1, and locking holes 2-2 are provided on the fixing module 2. The locking holes 2-2 are used in cooperation with the positioning holes 1-2 to generate restraint on the cold plate 5 to be welded throughout the welding process in cooperation with the pressing plate 3.

[0008] Further, after pressing the cold plate 5 to be welded into the bottom plate 4, welding is performed, and the weld seam is the gap between the cold plate 5 to be welded and the bottom plate 4.

[0009] The present invention also provides a laser welding method for a thin-walled titanium alloy flow channel plate. The laser welding method includes the following steps:

[0010] Clamp the cold plate to be welded using the above-mentioned laser welding tooling;

[0011] Use a thin-diameter welding wire, adjust the laser power, turn on the purge of the shielding gas, and perform laser welding starting from the lower left and in a counterclockwise direction;

[0012] During the welding process, active cooling is carried out until the welding is completed;

[0013] After the welding is completed, disassemble the fixing module;

[0014] The specific active cooling is as follows: Spray anhydrous ethanol on the welded surface. After the anhydrous ethanol on the surface of the cold plate 5 to be welded has volatilized completely and ventilation has been maintained for 2 minutes, turn on the purge of the shielding gas again for 10 seconds to complete one active cooling.

[0015] Further, the specific thin-diameter welding wire is a welding wire with a diameter of 0.2 to 0.3 mm;

[0016] The specific adjustment of the laser power is as follows: Use a welding power of 50 to 80 W; Reduce the input energy of the laser to the lowest level.

[0017] Further, the specific laser welding sequence is as follows: When welding the weld seam parallel to the fixing module 2, do not disassemble. When welding to the weld seam perpendicular to the fixing module 2, disassemble the fixing module 2 in sequence.

[0018] Further, the selection timing of the active cooling is to perform active cooling when reaching one-third of the length of each weld seam. It is necessary to remove the fixing module 2 for welding and active cooling after welding and then reinstall the fixing module 2, and continue to remove the next fixing module 2 for welding and active cooling after welding, and cycle until the welding is completed.

[0019] Further, one weld seam is welded in 3 times to balance the relationship between heat accumulation and thermal accumulation deformation during the welding process.

[0020] Further, the shielding gas is argon;

[0021] The ventilation is room-temperature air.

[0022] The present invention also provides a laser welding system for a thin-walled titanium alloy flow channel plate, which is characterized by including the laser welding method for the thin-walled titanium alloy flow channel plate described above.

[0023] The technical solution of the present invention has the following advantages:

[0024] Without sacrificing the performance of the titanium alloy liquid cooling plate, the present invention effectively ensures the welding accuracy of the cold plate to be welded.

[0025] The tooling fixture of the present invention adopts a three-section detachable structure, which not only ensures the restraint of the cold plate to be welded during the whole welding process, but also ensures that the flow of the shielding gas is not hindered during the whole welding process.

[0026] In order to control the degree of thermal deformation of the workpiece, the present invention must weaken the positive influencing factors such as laser power, welding time and welding path, and strengthen the negative influencing factors such as active cooling and the restraint of the welding tooling.

[0027] The present invention considers the correction process after the thermal deformation of the titanium alloy metal to achieve the purpose of preventing the workpiece from exceeding the tolerance.

[0028] The weld of the present invention is complete, and the thermal deformation of the workpiece can be controlled within 0.1 mm.

[0029] The invention content part is provided to introduce the selection of concepts in a simplified form, which will be further described in the specific implementation manner below. The invention content part is not intended to identify the important features or essential features of the present disclosure, nor is it intended to limit the scope of the present disclosure. Brief Description of the Drawings

[0030] In order to more clearly illustrate the specific implementation manner of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required to be used in the specific implementation manner or the description of the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 It is a schematic diagram A of placing the cold plate to be welded into the inner groove of the outer frame provided by the present invention.

[0032] Figure 2 It is a schematic diagram B of placing the cold plate to be welded into the inner groove of the outer frame provided by the present invention.

[0033] Figure 3 It is a schematic diagram of the tooling fixture structure provided by the present invention.

[0034] Figure 4 It is a schematic diagram of the welding sequence provided by the present invention.

[0035] Figure 5 It is Sequence Diagram A of the welding and active cooling of the disassembly fixing module provided by the present invention.

[0036] Figure 6 It is Sequence Diagram B of the welding and active cooling of the disassembly fixing module provided by the present invention.

[0037] Figure 7 It is Sequence Diagram C of the welding and active cooling of the disassembly fixing module provided by the present invention.

[0038] Figure 8 It is a schematic diagram for analyzing the bottom events of the welding process provided by the present invention.

[0039] Figure 9 It is a physical picture of on-site welding provided by the present invention.

[0040] Figure 10 It is a method flow chart provided by the present invention.

[0041] Description of reference numerals:

[0042] Outer frame 1, fixing module 2, pressing plate 3, bottom plate 4, cold plate to be welded 5, groove 1-1, positioning hole 1-2, locking hole 2-2. Detailed implementation manners

[0043] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are presented in order to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0044] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0045] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification of the present application and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0046] It should also be understood that in the description of the present disclosure, the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present disclosure. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present disclosure, "a plurality" means two or more unless otherwise specifically defined.

[0047] It should also be understood that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "mounted", "connected" and "coupled" shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, an electrical connection or a connection capable of mutual communication; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure may be understood according to specific circumstances.

[0048] The following will, with reference to the appended drawings of the present application Figure 1-10 clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

[0049] Many specific details are set forth in the following description in order to provide a thorough understanding of the present application. However, the present application may be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0050] The main source of thermal deformation during the laser welding of titanium alloy thin plates is heat accumulation. In laser welding, the titanium alloy material around the weld seam is rapidly heated, and over time, the temperature of the heated area gradually increases, leading to the accumulation of local thermal expansion and thermal stress. Due to the small coefficient of thermal expansion of titanium alloy and the slow heat conduction process, the accumulation of thermal stress occurs. At the same time, due to the thin thickness of the plate, obvious thermal deformation is easily caused.

[0051] Among them, the three basic events that cause heat accumulation factors are laser power, welding time, and active cooling; the two basic events that cause thermal deformation accumulation factors are welding path and fixture. Therefore, to control the degree of thermal deformation of the workpiece, it is necessary to weaken the positive influencing factors such as laser power, welding time, and welding path, and strengthen the negative influencing factors such as active cooling and welding fixture restraint. At the same time, the correction process of titanium alloy metal thermal deformation should be considered to achieve the process purpose of preventing the workpiece from exceeding the tolerance.

[0052] As Figure 1-Figure 6 shown, a laser welding fixture for a thin-walled titanium alloy flow channel plate, the laser welding fixture includes an outer frame 1, a plurality of fixing modules 2, a pressing plate 3, a bottom plate 4, and a cold plate 5 to be welded. A groove 1-1 is opened at the upper end of the outer frame 1, the bottom plate 4 is installed in the groove 1-1, the cold plate 5 to be welded is pressed into the bottom plate 4, the pressing plate 3 is placed on the bottom plate 4, the area of the pressing plate 3 is smaller than that of the cold plate 5 to be welded, and each side length of the pressing plate 3 is 0.1-0.3 mm away from the weld seam of the cold plate 5 to be welded. On the premise of ensuring that the weld seam is exposed, the pressure between the cold plate 5 to be welded and the bottom plate 4 should also be maintained. The superposed height of the bottom plate 4 and the pressing plate 3 embedding the cold plate 5 to be welded is less than or equal to the wall height of the groove 1-1. The plurality of fixing modules 2 cooperate with the outer frame 1 to clamp the bottom plate 4 embedding the cold plate 5 to be welded by the pressing plate 3, maintain the pressure during the laser welding process, and ensure that the flow of the shielding gas is not hindered during the whole welding process.

[0053] Furthermore, positioning holes 1-2 are provided on the outer frame 1, and locking holes 2-2 are provided on the fixing modules 2. The locking holes 2-2 are used in cooperation with the positioning holes 1-2 to generate restraint on the cold plate 5 to be welded by the pressing plate 3 during the whole welding process, maintain the pressure between the cold plate 5 to be welded and the bottom plate 4, and prevent it from warping during welding, ensuring the quality after welding.

[0054] Furthermore, after the cold plate 5 to be welded is pressed into the bottom plate 4, welding is carried out, and its weld seam is the gap between the cold plate 5 to be welded and the bottom plate 4.

[0055] A laser welding method for a thin-walled titanium alloy flow channel plate, the laser welding method includes the following steps:

[0056] Clamp the cold plate to be welded using the above laser welding fixture;

[0057] Use a thin-diameter welding wire, adjust the laser power, turn on the shielding gas purge, and start from the lower left and move counterclockwise (i.e., in the direction of A→B, C→D, as Figure 4 shown) to perform laser welding;

[0058] During the welding process, active cooling is carried out until the welding is completed;

[0059] After the welding is completed, remove the fixing module in the direction from left to right, starting from the bottom and then moving up (i.e., in the direction of C→A, D→B, as Figure 5 shown).

[0060] Furthermore, the thin-diameter welding wire specifically uses a welding wire with a diameter of 0.2 - 0.3 mm; this is because in order to reduce the input energy of the laser, the welding power needs to be reduced. To improve efficiency, the diameter of the welding wire is reduced.

[0061] The adjustment of the laser power specifically uses a welding power of 50 - 80 W; the input energy of the laser is reduced to the lowest.

[0062] Furthermore, the laser welding sequence specifically is that when welding the weld parallel to the fixing module 2, it is not disassembled. When welding to the weld perpendicular to the fixing module 2, the fixing module 2 is disassembled in sequence.

[0063] Furthermore, the timing of the active cooling is to perform active cooling when reaching one-third of the length of each weld. It is necessary to remove the fixing module 2 for welding and active cooling after welding and then reinstall the fixing module 2, and continue to remove the next fixing module 2 for welding and active cooling after welding, cycling until the welding is completed.

[0064] Furthermore, the active cooling specifically is to spray anhydrous ethanol onto the welded surface. After the anhydrous ethanol on the surface of the cold plate 5 to be welded has completely volatilized and ventilation has been maintained for 2 minutes, the shielding gas purge is turned on again for 10 s to complete one cycle of active cooling.

[0065] Furthermore, one weld is divided into 3 times of welding to balance the relationship between heat accumulation and thermal accumulation deformation during the welding process.

[0066] Furthermore, the shielding gas is argon;

[0067] The ventilation is room-temperature air.

[0068] A laser welding system for a thin-walled titanium alloy flow channel plate includes the laser welding method for the thin-walled titanium alloy flow channel plate described above.

[0069] As Figure 7 shown,

[0070] Analysis of Basic Events in Welding Process

[0071] Serial number Symbol of basic event Content of basic event Influence effect Influence direction 1 X1 Laser power Heat accumulation Positive direction 2 X2 Welding time Heat accumulation Positive direction 3 X3 Active cooling Heat accumulation Negative direction 4 X4 Welding path Accumulation of thermal deformation Positive direction 5 X5 Tooling fixture Accumulation of thermal deformation Negative direction 6 X6 Post-welding straightening Out-of-tolerance deformation Negative direction

[0072] Laser Power X1

[0073] Reducing the laser power can effectively prevent heat accumulation during the welding process. However, to ensure the welding strength, in this invention, the method of reducing the wire diameter is adopted to significantly reduce the laser welding power and minimize the laser input energy to the lowest level.

[0074] Welding Time X2

[0075] During the continuous welding process, the welding time will directly affect the heat accumulation during welding, and overly frequent interruption of the welding process will also affect the weld quality. Therefore, in this invention, each weld is welded in 3 segments to minimize the heat accumulation factor brought by the welding time.

[0076] Active Cooling X3

[0077] Active cooling will significantly reduce the heat accumulation during the welding process. Since the weld needs to be protected by argon gas throughout the welding process, the adjustable range of the argon gas purging speed is limited. At the same time, considering the cost, it is not suitable to rely entirely on argon gas purging for cooling. Therefore, during the welding process, anhydrous ethanol is sprayed during the welding interval for active cooling, and at the same time, active ventilation is turned on to eliminate potential safety hazards.

[0078] Tooling Fixture X5

[0079] Through targeted design, the tooling fixture adopts a three - segment detachable structure, which not only ensures the restraint of the workpiece during the whole welding process but also ensures that the flow of the shielding gas is not blocked during the whole welding process.

[0080] Adopting low - energy filler wire welding, a tooling form suitable for the flow of shielding gas and with full - process clamping, combined with a process plan of thin wire, segmented welding and active cooling, solves the problem of laser welding of titanium alloy thin plates.

[0081] The final process parameters of this invention are as follows: laser power 50 - 80W, pulse width 8 - 10MS, weld width 0.5 - 0.8mm, weld depth 0.5 - 0.8mm, wire 0.2 - 0.3mm. Manual segmented welding is adopted. After welding one segment, the welding is stopped, and active cooling such as using anhydrous ethanol is carried out to try to maintain the workpiece at room temperature during the welding process. After welding, the weld is complete, and the thermal deformation of the workpiece can be controlled within 0.1mm.

Claims

1. A laser welding tooling for a thin-walled titanium alloy flow channel plate, characterized in that, The laser welding tooling includes an outer frame (1), a plurality of fixing modules (2), a pressing plate (3), a bottom plate (4), and a cold plate to be welded (5). A groove (1-1) is formed at the upper end of the outer frame (1), the bottom plate (4) is placed in the groove (1-1), the cold plate to be welded (5) is pressed into the bottom plate (4), the pressing plate (3) is placed on the bottom plate (4), the area of the pressing plate (3) is smaller than that of the cold plate to be welded (5), each side length of the pressing plate (3) is 0.1-0.3 mm away from the weld of the cold plate to be welded (5), the superposition height of the bottom plate (4) and the pressing plate (3) embedded with the cold plate to be welded (5) is less than or equal to the wall height of the groove (1-1). The plurality of fixing modules (2) cooperate with the outer frame (1) to clamp the bottom plate (4) embedded with the cold plate to be welded (5) by the pressing plate (3), maintain pressure during the laser welding process, and ensure that the flow of the shielding gas is not obstructed during the entire welding process.

2. The laser welding tooling according to claim 1, characterized in that, Positioning holes (1-2) are provided on the outer frame (1), locking holes (2-2) are provided on the fixing modules (2), the locking holes (2-2) are used in cooperation with the positioning holes (1-2), and the cold plate to be welded (5) is constrained by the pressing plate (3) during the entire welding process.

3. The laser welding tooling according to claim 1, characterized in that, After pressing the cold plate to be welded (5) into the bottom plate (4), welding is performed, and the weld is the gap between the cold plate to be welded (5) and the bottom plate (4).

4. A laser welding method for a thin-walled titanium alloy flow channel plate, characterized in that, The laser welding method includes the following steps: Clamp the cold plate to be welded using the laser welding tooling as described in any one of claims 1-3; Use a thin-diameter welding wire, adjust the laser power, turn on the shielding gas purge, and perform laser welding starting from the lower left and in a counterclockwise direction; During the welding process, active cooling is carried out until the welding is completed; After the welding is completed, remove the fixing modules; The specific active cooling is as follows: Sprinkle anhydrous ethanol on the welded surface. After the anhydrous ethanol on the surface of the cold plate to be welded (5) has volatilized, and after ventilation for 2 minutes, turn on the shielding gas purge again for 10 seconds to complete one active cooling.

5. The laser welding method according to claim 4, characterized in that, The specific thin-diameter welding wire is a welding wire with a diameter of 0.2-0.3 mm; The specific adjustment of the laser power is as follows: Use a welding power of 50-80 W; reduce the input energy of the laser to the lowest level.

6. The laser welding method according to claim 4, characterized in that, The specific laser welding sequence is as follows: When welding the weld parallel to the fixing module (2), do not disassemble. When welding the weld perpendicular to the fixing module (2), remove the fixing module (2) in sequence.

7. The laser welding method according to claim 6, characterized in that, The selection timing of the active cooling is to perform active cooling when the length of each weld reaches one-third. It is necessary to remove the fixing module (2) for welding and active cooling after welding and then reinstall the fixing module (2), and continue to remove the next fixing module (2) for welding and active cooling after welding, and cycle until the welding is completed.

8. The laser welding method according to claim 6 or 7, characterized in that, One weld is divided into 3 times of welding to balance the relationship between heat accumulation and thermal accumulation deformation during the welding process.

9. The laser welding method according to claim 3, characterized in that, The shielding gas is argon; The ventilation is room-temperature air.

10. A laser welding system for a thin-walled titanium alloy flow channel plate, characterized in that, It includes a laser welding method using the thin-walled titanium alloy flow channel plate as described in any one of claims 4-9.

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