Welding method for titanium alloy thick plate

Abstract

The invention discloses a welding method for titanium alloy thick plates, and relates to the technical field of laser welding, and the method comprises the following steps: placing a plurality of titanium alloy thick plates to be welded on a workbench, carrying out backing welding on backing welding areas of the titanium alloy thick plates to be welded, and carrying out continuous laser processing through picosecond pulse laser, reciprocating motion is conducted in the molten pool and the forging area; after the backing welding process is finished, a first laser wire filling welding area and a second laser wire filling welding area between different titanium alloy thick plates to be welded are welded in a laser wire filling welding mode, in the welding process, picosecond pulse laser follows continuous laser machining, and the welding process is completed. And reciprocating motion is conducted in the molten pool and the forging area according to a preset motion trail, so that different titanium alloy thick plates to be welded are welded. The technical effect that uneven distribution of the structure performance of the welding joint is avoided is achieved.

Description

Technical Field

[0001] This application relates to the field of laser welding technology, and more specifically to a welding method for thick titanium alloy plates. Background Technology

[0002] Titanium alloys, with their excellent corrosion resistance and high specific strength, have been increasingly widely used in the field of marine engineering equipment. With the growing demand for larger and lighter marine engineering equipment, medium-thick titanium alloy plate structures have become an urgent need, and welding technology is one of the key technologies to ensure the safe service of these structures.

[0003] Currently, the joining of thick titanium alloy plates mainly utilizes two technologies: gas inert gas welding (TIG) and vacuum electron beam welding (VEBW). TIG welding, due to its relatively large bevel angle and root gap, suffers from the following problems: it easily generates defects such as porosity and cracks during welding, and its multi-layer, multi-pass welding is inefficient, resulting in high residual stress and affecting the mechanical properties of the joint. VEBW welding is limited by the high vacuum environment, restricting the size and specifications of the welded components, and is not always suitable for large or specially shaped titanium alloy parts. Laser filler wire welding (NG-LWFW), compared to TIG and VEBW welding, has advantages such as lower heat input, a limited heat-affected zone, and precise controllable energy input. Furthermore, laser filler wire welding technology is not limited by the size and specifications of the titanium alloy thick plate welded components, and can excellently complete high-quality, high-efficiency joining of large titanium alloy thick plate structural parts. However, existing laser filler wire welding techniques for thick titanium alloy plates suffer from problems such as sidewall incomplete fusion, weld porosity, severe weld deformation and stress concentration, and uneven distribution of microstructure and properties in the welded joint. Summary of the Invention

[0004] In order to address the technical problems in existing laser wire-filled welding of thick titanium alloy plates, such as sidewall incomplete fusion, weld porosity, severe welding deformation and stress concentration, as well as uneven distribution of microstructure and properties of the welded joint, this application provides a welding method for thick titanium alloy plates.

[0005] The specific technical solution adopted is as follows: Multiple titanium alloy thick plates to be welded are placed on the worktable, and the root welding area of ​​the titanium alloy thick plates to be welded is welded. The plates are then processed by picosecond pulsed laser following continuous laser processing, and the plates are moved back and forth in the molten pool and forging area. After the root pass welding process is completed, the first laser filler welding area and the second laser filler welding area between different titanium alloy thick plates to be welded are welded using the laser filler welding mode. During the welding process, the picosecond pulse laser follows the continuous laser processing and moves back and forth in the molten pool and forging area according to the preset motion trajectory to weld the different titanium alloy thick plates to be welded together.

[0006] In one possible embodiment of this application, before placing multiple titanium alloy plates to be welded on the worktable, the method further includes: The welding head of the titanium alloy thick plate to be welded is processed into a symmetrical multi-level trapezoidal structure, and the multi-level trapezoidal structure is cleaned by removing impurities and oil stains.

[0007] In one possible embodiment of this application, a root pass weld is performed on the thick titanium alloy plate to be welded, and picosecond pulsed laser follows continuous laser processing, reciprocating between the molten pool and the forging zone, including: Welding is performed on the root pass area between different titanium alloy thick plates to be welded using a single continuous laser. Welding proceeds straight from one end to the other along the connection between the two titanium alloy thick plates to be welded, and a picosecond pulsed laser is used to follow the continuous laser processing. The process moves back and forth in the molten pool and forging zone. The root pass is a deep penetration welding mode.

[0008] In one possible implementation of this application, the motion trajectories of the continuous laser and the picosecond pulse laser are independently controlled by two sets of galvanometer control modules. After the picosecond pulse laser exits the galvanometer, it is converted from Gaussian light to Bessel light by an axonal pyramid.

[0009] In one possible embodiment of this application, before performing the root pass welding on the thick titanium alloy plate to be welded, the following steps are also included: By using a protective gas delivery device to ventilate the upper and lower sides of the welding area of ​​the thick titanium alloy plate to be welded, the air is expelled, so that the welding area is completely surrounded by protective gas.

[0010] In one possible embodiment of this application, the protective gas is argon or helium.

[0011] In one possible embodiment of this application, welding is performed on a first laser-filled wire welding zone and a second laser-filled wire welding zone between different titanium alloy thick plates to be welded using a laser-filled wire welding mode, including: Welding is performed on the first laser-filled wire welding area between different thick titanium alloy plates using laser-filled wire welding mode. The welding wire is fed to the welding position corresponding to the continuous laser by a wire feeding mechanism. After the first stepped structure of the first laser-filled wire welding area is welded, the thick titanium alloy plate to be welded is flipped over, and the first stepped structure of the second laser-filled wire welding area is welded. After the welding of the first stepped structure is completed, the thick titanium alloy plate to be welded is flipped over again, and the welding of the second stepped structure of the first laser-filled wire welding area begins. The above process is repeated until the welding of the first laser-filled wire welding area and the second laser-filled wire welding area is completed.

[0012] In one possible implementation of this application, a picosecond pulsed laser follows continuous laser processing, reciprocating between the molten pool and the forging zone according to a preset motion trajectory, including: The continuous laser is controlled to perform a circular offset motion. After completing one revolution, the continuous laser is controlled to deflect 1mm~2mm along the welding direction before the next circular motion is performed. This cycle is repeated. The scanning head of the picosecond pulse laser moves synchronously with the continuous laser welding head, reciprocating between the molten pool and the forging zone.

[0013] In one possible embodiment of this application, the adjacent upper and lower weld beads of the same welding area of ​​the titanium alloy thick plate to be welded are offset by a preset angle, and the offset direction is clockwise or counterclockwise.

[0014] In one possible embodiment of this application, after welding the first laser-filled wire welding area and the second laser-filled wire welding area between different titanium alloy thick plates to be welded using a laser-filled wire welding mode, the process further includes: After the welding of the thick titanium alloy plate is completed, the welding area is ground, polished, cleaned of impurities and oil, and painted according to the preset requirements.

[0015] This application has, but is not limited to, the following technical effects: By placing the titanium alloy thick plate to be welded on the worktable, the root pass welding area of ​​the titanium alloy thick plate is performed, and picosecond pulsed laser follows continuous laser processing, reciprocating between the molten pool and the forging zone. After the root pass welding process is completed, laser filler wire welding is used to weld the first and second laser filler wire welding areas between different titanium alloy thick plates. Similarly, picosecond pulsed laser follows continuous laser processing, reciprocating between the molten pool and the forging zone to weld different titanium alloy thick plates. In this application, dual laser beams work together. The continuous laser is used to melt the welding wire for the main welding work, while the picosecond pulsed laser is selected and follows the continuous laser to weld the molten pool and the forging zone behind the molten pool. The weld bead reciprocates to perform scanning irradiation. Irradiation of the molten pool mainly accelerates the removal of bubbles within the pool, reducing porosity defects in the weld bead. Scanning irradiation of the weld bead behind the molten pool in the forging zone primarily induces stress release through high-frequency micro-disturbance in the thermoplastic state. Utilizing the high repetition rate (300kHz) of the picosecond laser, high-frequency thermal disturbances and micro-shock waves are generated in the forging zone where the material is in a thermoplastic state. Through cumulative effects, microscopic plastic deformation of the crystal lattice is induced, releasing tensile stress online and refining grains, significantly reducing residual stress. By controlling the laser beam movement and welding path, the solidification behavior of the molten pool and the grain growth direction are directly affected, achieving isotropic microstructure and mechanical properties, and solving the problems of uneven distribution of microstructure and properties in welded joints and incomplete fusion of sidewalls. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of the first embodiment of the welding method for thick titanium alloy plates according to this application; Figure 2 This is a schematic diagram of the titanium alloy thick plate welding joint involved in the welding method for titanium alloy thick plates used in this application; Figure 3 This is a schematic diagram of the trapezoidal structure of the titanium alloy thick plate involved in the welding method of the titanium alloy thick plate used in this application; Figure 4 This is a schematic diagram of the dual-laser beam synergistic welding method used in this application for welding thick titanium alloy plates; Figure 5 This is the continuous laser motion trajectory involved in the welding method for thick titanium alloy plates in this application; Figure 6 This is a schematic diagram of the picosecond laser motion trajectory involved in the welding method for thick titanium alloy plates used in this application; Figure 7 This is a schematic diagram of the device structure of the hardware operating environment involved in the embodiments of this application. Detailed Implementation

[0017] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0018] This application provides a welding method for thick titanium alloy plates. In the first embodiment of the welding method for thick titanium alloy plates in this application, refer to... Figure 1 The methods include: Step S10: Place multiple titanium alloy thick plates to be welded on the worktable, perform root welding on the root welding area of ​​the titanium alloy thick plates to be welded, and perform picosecond pulsed laser following continuous laser processing, reciprocating between the molten pool and the forging area. As an example, the welding method for thick titanium alloy plates can be applied to welding apparatus for thick titanium alloy plates, which belongs to welding system for thick titanium alloy plates, and the welding system for thick titanium alloy plates belongs to welding equipment for thick titanium alloy plates.

[0019] As an example, multiple titanium alloy plates can be welded together. Here, we take the welding of two titanium alloy plates as an example. The thickness of the titanium alloy plates to be welded is greater than or equal to 20 mm. The titanium alloy plates to be welded can be TC4 titanium alloy plates.

[0020] As an example, this application employs a dual-laser beam welding method, comprising a continuous laser beam and a pulsed laser beam. The continuous laser is used to melt the welding wire and perform the main welding work, while the pulsed laser is a picosecond-level pulsed laser that follows the continuous laser to scan and irradiate the weld bead portion within the molten pool and behind it in the forging zone.

[0021] As an example, the forging zone refers to the forging area of ​​the welded zone in a thick titanium alloy plate, and this zone is determined by the forging temperature range of the titanium alloy material. The forging temperature range of a metal refers to the optimal temperature range within which the metal material can maintain good plastic deformation capacity while avoiding defects during forging (hot working). This range lies between a maximum temperature (upper limit) and a minimum temperature (lower limit). The forging temperature range of titanium alloys is highly dependent on the specific alloy grade (α-type, near-α-type, α+β-type, near-β-type, β-type) and the desired microstructure / properties (especially whether α+β forging yields an equiaxed structure or β forging yields a lamellar structure). Taking TC4 titanium alloy as an example, its typical initial forging temperature is 925℃~970℃, and its typical final forging temperature is 700℃~800℃. The forging zone is detected by a thermal imager, and the information is fed back to the computer. The computer then controls the galvanometer system to determine the movement of the picosecond pulse laser. The temperature field distribution of the welding area is monitored in real time by an infrared thermal imager. The area with a temperature within the preset forging temperature range (e.g., 700℃~970℃) is defined as the forging zone, and the position coordinates of this area are fed back to the picosecond laser control system in real time.

[0022] As an example, a molten pool refers to a liquid metal region formed during welding when the base metal and filler metal are locally melted and mixed under the direct action of a heat source (such as an electric arc, laser, or electron beam).

[0023] The process of placing multiple thick titanium alloy plates to be welded on the workbench also includes: The welding head of the titanium alloy thick plate to be welded is processed into a symmetrical multi-level trapezoidal structure, and the multi-level trapezoidal structure is cleaned by removing impurities and oil stains.

[0024] As an example, a schematic diagram of a titanium alloy thick plate welding joint is shown below. Figure 2 As shown, the blank areas represent titanium alloy plate 1 and titanium alloy plate 2, respectively. The black welded joint in the middle is the root pass welding area, with a height (blunt edge) of 10mm. Titanium alloy plate 1 and titanium alloy plate 2 are each equipped with a processed multi-level trapezoidal structure. The area between the two titanium alloy plates is laser wire filler welding area 1 and laser wire filler welding area 2, respectively. A schematic diagram of the trapezoidal steps of the multi-level trapezoidal structure is shown below. Figure 3As shown, the width a is 5mm, the height b is 10mm, the height of the trapezoidal structure on the upper and lower sides of the titanium alloy plate can be selected within the range of 5mm to 15mm, and the single-sided bevel angle θ is 3° to 5°.

[0025] Step S10 further includes: Welding is performed on the root pass area between different titanium alloy thick plates to be welded using a single continuous laser. Welding proceeds straight from one end to the other along the connection between the two titanium alloy thick plates to be welded, and a picosecond pulsed laser is used to follow the continuous laser processing. The process moves back and forth in the molten pool and forging zone. The root pass is a deep penetration welding mode.

[0026] As an example, the root pass welding stage uses laser welding mode, not laser filler wire welding. Shielding gas needs to be introduced on both the upper and lower sides of the welding area beforehand to ensure the welding area is completely enclosed in shielding gas. The connection point is also the welding area. The continuous laser welds straight along the connection point of TC4 titanium alloy thick plates 1 and 2 from one end to the other. The picosecond pulsed laser follows the continuous laser processing, reciprocating between the molten pool and the forging zone. The picosecond laser's main function in this stage is to act on the surface of the molten pool and the upper area, suppressing undercut caused by surface tension, and performing micro-forging on the heat-affected zone.

[0027] Specifically, the laser parameters for the root pass welding are: laser power 5.5kW, welding speed 2m / min, defocusing amount 0; shielding gas: 99.99% argon, flow rate 25L / min; picosecond pulse laser parameters are: laser wavelength 1030nm, pulse width 10ps, single pulse energy 80μJ, spot size 30μm, repetition frequency 300kHz, scanning speed 5m / s.

[0028] The motion trajectories of the continuous laser and the picosecond pulse laser are independently controlled by two sets of galvanometer control modules. After the picosecond pulse laser comes out of the galvanometer, it is converted from Gaussian light to Bessel light by an axonal pyramid.

[0029] As an example, after being reflected by a galvanometer, the picosecond pulsed laser needs to pass through an axonoid to convert the Gaussian light into Bessel light. This process requires controlling the spatial movement of the axonoid to ensure that the picosecond pulsed laser passes through the axonoid and enters vertically, thus ensuring the stability of the Bessel light. The picosecond pulsed laser follows continuous laser processing and moves back and forth in the molten pool and forging zone.

[0030] As an example, using an axial pyramid to generate a Bessel beam is to obtain a long focal depth to accommodate the height variations of the surface of thick, multi-layered weld beads, ensuring a continuous and stable energy density applied to the molten pool and forging zone without the need for frequent mechanical focusing.

[0031] Before performing the root pass welding on the thick titanium alloy plate to be welded, the process also includes: By using a protective gas delivery device, air is vented to the upper and lower sides of the welding area of ​​the thick titanium alloy plate to be welded, and the air is expelled so that the welding area is completely surrounded by protective gas, which is 99.99% argon or 99.99% helium.

[0032] Step S20: After the root pass welding process is completed, the first laser filler welding area and the second laser filler welding area between different titanium alloy thick plates to be welded are welded using the laser filler welding mode. During the welding process, the picosecond pulse laser follows the continuous laser processing and moves back and forth in the molten pool and forging area according to the preset motion trajectory to weld the different titanium alloy thick plates to be welded together.

[0033] As an example, the first laser-welded wire feed zone is... Figure 2 Laser filler wire welding zone 1, and the second laser filler wire welding zone are... Figure 2 The laser filler wire welding zone 2 in the middle. The preset motion trajectory can be a reciprocating circular motion trajectory.

[0034] As an example, after the initial welding is completed, the process switches to laser wire filler welding mode. First, welding is performed on the first laser wire filler welding area, followed by the second laser wire filler welding area. During this stage of welding, the wire feeding mechanism delivers the welding wire to the welding point corresponding to the continuous laser, such as... Figure 4 As shown, the continuous laser performs a circular offset motion, meaning that after completing one revolution, the continuous laser offsets 1mm~2mm along the welding direction before starting the next circular motion. Its trajectory is as follows: Figure 5 As shown.

[0035] Step S20 includes: Welding is performed on the first laser-filled wire welding area between different thick titanium alloy plates using laser-filled wire welding mode. The welding wire is fed to the welding position corresponding to the continuous laser by a wire feeding mechanism. After the first stepped structure of the first laser-filled wire welding area is welded, the thick titanium alloy plate to be welded is flipped over, and the first stepped structure of the second laser-filled wire welding area is welded. After the welding of the first stepped structure is completed, the thick titanium alloy plate to be welded is flipped over again, and the welding of the second stepped structure of the first laser-filled wire welding area begins. The above process is repeated until the welding of the first laser-filled wire welding area and the second laser-filled wire welding area is completed.

[0036] As an example, both the first and second laser wire-filling welding areas have a first trapezoidal structure and a second trapezoidal structure. After the trapezoidal structure in the first or second laser wire-filling welding area is welded, the welding of the two titanium alloy thick plates is completed. The purpose of flip welding is to use the thermal stress on the rear side to offset the deformation trend of the front side by applying heat input alternately and symmetrically, and to achieve low deformation control of the thick plate in conjunction with the online stress elimination of the picosecond laser.

[0037] In step S20, the continuous laser parameters are: laser power 4kW, welding speed 0.5m / min, defocusing amount -2mm; the picosecond pulse laser parameters are: laser wavelength 1030nm, pulse width 10ps, single pulse energy 80μJ, spot size 30μm, repetition frequency 300kHz, scanning speed 5m / s; welding wire: TC3 welding wire, diameter 1.2mm, wire feed speed 3m / min, wire feed angle 40°~45°; shielding gas: 99.99% argon gas, flow rate 15L / min.

[0038] In step S20, the picosecond pulsed laser follows the continuous laser processing, reciprocating between the molten pool and the forging zone according to a preset motion trajectory, including: The continuous laser is controlled to perform a circular offset motion. After completing one revolution, the continuous laser is controlled to offset 1mm~2mm along the welding direction before the next circular motion is performed. This cycle is repeated. The scanning head of the picosecond pulse laser moves synchronously with the continuous laser welding head, reciprocating between the molten pool and the forging zone. The radius of the continuous laser's circular motion should be greater than the offset (1-2mm), and there should be an overlapping area between the circular trajectories.

[0039] As an example, picosecond pulsed lasers follow continuous laser processing, reciprocating between the molten pool and the forging zone, with a trajectory as follows: Figure 6 As shown, the protective gas delivery device is always on to ensure that the welding area is protected by protective gas. The protective gas delivery device can be turned off when the temperature of the welding area is below 100°.

[0040] Specifically, the scanning head of the picosecond pulsed laser moves synchronously with the continuous laser welding head, but is controlled by an independent galvanometer system to perform independent high-frequency scanning within the area including the molten pool and the forging zone behind the molten pool.

[0041] The adjacent upper and lower weld beads in the same welding area of ​​the titanium alloy thick plate to be welded are offset by a preset angle, and the offset direction is clockwise or counterclockwise.

[0042] As an example, the preset angle can be 67°, 68°, etc., and there is no specific limitation. The welding path adopted by laser filler wire welding is as follows: in the same welding area, the adjacent upper and lower weld layers need to be offset by 67°. The offset direction can be clockwise or counterclockwise, but the offset direction must be kept consistent throughout the welding process. The single-pass welding adopts a welding mode that starts from the edge of one titanium alloy thick plate and ends at the edge of another titanium alloy thick plate.

[0043] After welding the first and second laser-filled wire welding zones between different titanium alloy thick plates using laser-filled wire welding mode, the process also includes: After the welding of the thick titanium alloy plate is completed, the welding area is ground, polished, cleaned of impurities and oil, and painted according to the preset requirements.

[0044] This application provides a welding method for thick titanium alloy plates. The method involves placing the thick titanium alloy plate to be welded on a worktable, performing a root pass welding on the plate's root pass area, and then using a picosecond pulsed laser following a continuous laser to reciprocate within the molten pool and forging zone. After the root pass welding process, a first and second laser-filled wire welding zone between different thick titanium alloy plates is welded using a laser-filled wire welding mode. Similarly, a picosecond pulsed laser follows a continuous laser to reciprocate within the molten pool and forging zone to weld the different thick titanium alloy plates together. In this application, dual laser beams work collaboratively. The continuous laser melts the welding wire for the main welding work, while the picosecond pulsed laser follows the continuous laser to weld the molten pool and... The weld bead portion behind the molten pool, located in the forging zone, reciprocates to perform scanning irradiation. Irradiation of the molten pool primarily accelerates the removal of bubbles within it, reducing porosity defects in the weld bead. Scanning irradiation of the weld bead portion behind the molten pool, located in the forging zone, primarily induces stress release through high-frequency micro-disturbance in the thermoplastic state. Utilizing the high repetition rate (300kHz) of the picosecond laser, high-frequency thermal disturbances and micro-shock waves are generated in the forging zone where the material is in a thermoplastic state. Through cumulative effects, microscopic plastic deformation of the crystal lattice is induced, releasing tensile stress online and refining grains, significantly reducing residual stress. By controlling the laser beam movement and welding path, the solidification behavior of the molten pool and the grain growth direction are directly affected, achieving isotropic microstructure and mechanical properties, and solving the problems of uneven distribution of microstructure and properties in the weld joint and incomplete fusion of the sidewalls.

[0045] Reference Figure 7 , Figure 7 This is a schematic diagram of the device structure of the hardware operating environment involved in the embodiments of this application.

[0046] like Figure 7As shown, the welding equipment for thick titanium alloy plates may include: a processor 1001, a memory 1003, and a communication bus 1002. The communication bus 1002 is used to realize the connection and communication between the processor 1001 and the memory 1003.

[0047] Optionally, the welding equipment for thick titanium alloy plates may also include a user interface, a network interface, a camera, RF (Radio Frequency) circuitry, sensors, a WiFi module, etc. The user interface may include a display screen and an input submodule such as a keyboard; optional user interfaces may also include standard wired or wireless interfaces. The network interface may include standard wired or wireless interfaces (such as a Wi-Fi interface).

[0048] Those skilled in the art will understand that Figure 7 The welding equipment structure shown in the figure for thick titanium alloy plates does not constitute a limitation on the welding equipment for thick titanium alloy plates, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0049] like Figure 7 As shown, the memory 1003, serving as a storage medium, may include an operating system, a network communication module, and a welding program for titanium alloy thick plates. The operating system is a program that manages and controls the hardware and software resources of the welding equipment for titanium alloy thick plates, supporting the operation of the welding program for titanium alloy thick plates and other software and / or programs. The network communication module is used to enable communication between the various components within the memory 1003, as well as communication with other hardware and software in the welding system for titanium alloy thick plates.

[0050] exist Figure 7 In the welding equipment for thick titanium alloy plates shown, the processor 1001 is used to execute the welding program for thick titanium alloy plates stored in the memory 1003 to implement the steps of the welding method for thick titanium alloy plates described above.

[0051] The specific implementation of the welding equipment for thick titanium alloy plates in this application is basically the same as the embodiments of the welding method for thick titanium alloy plates described above, and will not be repeated here.

[0052] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0053] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0054] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0055] The above are merely preferred embodiments of this application and do not limit the scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of this application.

[0056] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0057] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A welding method for a titanium alloy thick plate, characterized by, The method comprises: Placing multiple titanium alloy thick plates to be welded on a workbench, performing primer welding on a primer welding area of the titanium alloy thick plates to be welded, and performing reciprocating movement in a molten pool and a forging area through picosecond pulse laser following continuous laser processing; After the primer welding process is completed, first laser filler welding areas and second laser filler welding areas between different titanium alloy thick plates to be welded are welded through a laser filler welding mode, and in the welding process, the picosecond pulse laser follows the continuous laser processing and performs reciprocating movement in the molten pool and the forging area according to a preset motion track, so as to weld the different titanium alloy thick plates to be welded.

2. The welding method for a titanium alloy thick plate according to claim 1, characterized by, Before the multiple titanium alloy thick plates to be welded are placed on the workbench, the method further comprises: The welding joints of the titanium alloy thick plates to be welded are processed into a symmetrical multi-stage trapezoidal structure, and the multi-stage trapezoidal structure part is subjected to cleaning treatment such as impurity and oil stain removal.

3. The welding method for a titanium alloy thick plate according to claim 1, characterized by, The primer welding area of the titanium alloy thick plates to be welded is subjected to primer welding, and reciprocating movement is performed in a molten pool and a forging area through picosecond pulse laser following continuous laser processing, which comprises: The primer welding areas between different titanium alloy thick plates to be welded are welded through a separate continuous laser, straight-line welding from one end to the other end along the connection of the two titanium alloy thick plates to be welded, and reciprocating movement is performed in a molten pool and a forging area through picosecond pulse laser following continuous laser processing, and the primer welding is a deep penetration welding mode.

4. The welding method for a titanium alloy thick plate according to claim 1, characterized by, The motion tracks of the continuous laser and the picosecond pulse laser are independently controlled by two sets of galvanometer control modules, and the picosecond pulse laser is converted from Gaussian light to Bessel light by an axicon after being output from the galvanometer.

5. The welding method for a titanium alloy thick plate according to claim 1, characterized by, Before the primer welding area of the titanium alloy thick plates to be welded is subjected to primer welding, the method further comprises: Air is discharged through the upper and lower sides of the welding position of the titanium alloy thick plates to be welded by a protective gas delivery device, so that the welding position is completely in the protective gas.

6. The welding method for a titanium alloy thick plate according to claim 5, characterized by, The protective gas is argon or helium.

7. The welding method for a titanium alloy thick plate according to claim 1, characterized by, The first laser filler welding areas and the second laser filler welding areas between different titanium alloy thick plates to be welded are welded through a laser filler welding mode, which comprises: The first laser filler welding areas between different titanium alloy thick plates to be welded are welded through a laser filler welding mode, and welding wire is sent to the welding position corresponding to the continuous laser through a wire feeding mechanism, after the first step-shaped structure part of the first laser filler welding area is welded, the titanium alloy thick plates to be welded are flipped, the first step-shaped structure part of the second laser filler welding area is welded, and after the welding is completed, the titanium alloy thick plates to be welded are flipped again, the second step-shaped structure part of the first laser filler welding area is welded, and the foregoing process is repeated until the first laser filler welding area and the second laser filler welding area are welded.

8. The welding method for a titanium alloy thick plate according to claim 1, characterized by, The picosecond pulse laser follows the continuous laser processing and performs reciprocating movement in a molten pool and a forging area according to a preset motion track, which comprises: The continuous laser is controlled to perform a circumferential offset motion, after a circle is completed, the continuous laser is controlled to offset 1mm-2mm along the welding direction, then the next circumferential motion is performed, and the cycle is repeated, and the scanning head of the picosecond pulse laser moves synchronously with the continuous laser welding head to move reciprocally in the molten pool and the forging area.

9. The welding method for a titanium alloy thick plate according to claim 1, characterized by, The adjacent upper and lower layers of welds of the same welding area of the titanium alloy thick plate to be welded are offset by a preset angle, and the offset direction is clockwise or counterclockwise.

10. The welding method for a titanium alloy thick plate according to claim 1, characterized by, After the first laser wire filling welding area and the second laser wire filling welding area between different titanium alloy thick plates to be welded are welded through the laser wire filling welding mode, the method further comprises the following steps of: After the welding work of the titanium alloy thick plate to be welded is completed, the welding area is polished, polished, decontaminated, degreased and painted according to the preset requirement.

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