Titanium alloy laser narrow gap welding device and method

Abstract

The present invention provides a titanium alloy laser narrow gap welding device and method, which relates to the field of welding technology. The welding device comprises: a motion platform, which is used to limit and fix a workpiece to be welded, and drive the workpiece to be welded to move along a first direction; a wire feeder, which is used to deliver welding to the narrow gap of the workpiece to be welded, and the welding wire is a thick core cable type welding wire; a conductive nozzle, which is arranged at the outlet end of the wire feeder and connected to a hot wire power supply, and is used to heat the welding wire; an oscillating laser gun, which is located above the motion platform and connected to a laser, and is used to emit a beam of periodically changing energy into the narrow gap of the workpiece to be welded, and the beam oscillates back and forth along a second direction, and the angle α formed between the first direction and the second direction is 60-120°. The present invention can increase the quality stability of welding, reduce the probability of interlayer and sidewall unfusion and pores, and improve the welding efficiency by more than 40% compared with the prior art.

Description

Technical Field

[0001] The present invention relates to the field of welding technology, and in particular to a titanium alloy laser narrow gap welding device and method. Background Art

[0002] Titanium and titanium alloys are widely used in aerospace, shipbuilding and marine engineering, nuclear power energy, bioengineering and other fields due to their good corrosion resistance, biocompatibility, excellent specific strength and specific stiffness. With the promotion of titanium alloy applications, the demand for large-thickness titanium alloy welding is increasing rapidly, and titanium alloy narrow-gap welding technology is developing rapidly.

[0003] Titanium alloy laser narrow gap welding technology uses laser as a high-quality heat source, utilizes its excellent energy density and directivity, and performs fusible wire welding under narrow gap grooves based on approximately parallel groove design, which has become a current research hotspot. To this end, the Chinese patent application number 202111603510.4 discloses an efficient welding method suitable for ultra-narrow gap welding of thick-walled titanium alloy components, including S1: processing grooves, pretreatment, and clamping; S2: laser hot wire welding under inert gas protection, the welding wire is a multi-strand twisted welding wire, and the welding wire is heated by a hot wire device. The laser beam and the normal of the plate are at a first angle, and the welding wire and the plate are at a second angle. There is no spacing between the laser beam incident point and the end of the welding wire; S3: After cleaning the weld, repeat single-layer single-pass welding until the weld is filled. This solution can greatly improve welding efficiency and achieve large-scale promotion and application in industry. However, the above scheme still has the following problems: 1) Since the energy density of the beam cross section of the common fiber laser is Gaussian distributed, and the liquid metal of titanium alloy has poor fluidity, the root side wall is often not fused due to insufficient heat; 2) Due to the difference in the spatial distribution of energy during the welding process, the temperature gradient varies greatly during welding, which easily forms defects such as pores; 3) In order to ensure welding efficiency under specific circumstances, only φ1.2mm or even thinner welding wire can be used for welding, and the deposition efficiency is extremely low, which limits engineering applications.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The problem solved by the present invention is that the existing titanium alloy laser narrow gap welding is prone to problems such as unfused side walls and welding pores, and the deposition efficiency is low.

[0006] In order to solve the above problems, the present invention provides a titanium alloy laser narrow gap welding device, comprising:

[0007] A motion platform, used for limiting and fixing the workpiece to be welded, and driving the workpiece to be welded to move along a first direction;

[0008] A wire feeder, used for delivering welding wire to the groove of the workpiece to be welded;

[0009] A conductive nozzle, arranged at the outlet end of the wire feeder and connected to a hot wire power supply, for heating the welding wire;

[0010] The oscillating laser gun is located above the motion platform and connected to the laser, and is used to emit a light beam with periodically changing energy into the groove of the workpiece to be welded. The light beam oscillates back and forth along the second direction, and the angle α formed between the first direction and the second direction is 60-120°.

[0011] The present invention can perform spatial energy modulation at the groove of the workpiece to be welded by arranging an oscillating laser gun, adopt a larger laser power in the side wall area close to the groove, and reduce the laser power near the center of the groove; at the same time, the conductive nozzle is used to preheat the welding wire before entering the molten pool, thereby solving the matching contradiction between the laser energy and the required melting energy of narrow gap laser welding, realizing high-quality melting under efficient wire feeding, and providing conditions for efficient and high-quality welding.

[0012] Preferably, the welding wire is a thick-core cable-type welding wire with a diameter of 1.6-2.4 mm. Due to the large specific surface area of ​​the thick-core cable-type welding wire, its efficiency in obtaining laser energy is greatly improved, which is conducive to the metal supplementation of the side wall to avoid side wall defects and achieve high-quality melting; at the same time, due to the release effect before the hot wire and the welding wire melt, its outline diameter becomes larger, avoiding the contradiction caused by the concentrated laser welding energy and the limited heating of the welding wire, thereby improving the welding quality.

[0013] Preferably, the welding wire is arranged through the conductive nozzle, and the conductive nozzle can apply alternating current to the welding wire. The magnetic field generated by the alternating current applied to the welding wire can stir the molten pool and refine the grains; at the same time, it ensures that the laser heat input during welding matches the required molten welding material and molten pool input.

[0014] Preferably, the hot wire power supply is connected to the conductive nozzle via a connecting wire, and a ground wire is provided on the hot wire power supply, and the other end of the ground wire is connected to the workpiece to be welded. This arrangement can form a current loop, thereby ensuring that current continuously passes through the welding wire to heat it. Preferably, the hot wire power supply generates alternating current. This arrangement can effectively avoid magnetic blow phenomenon, and at the same time can increase the periodic stirring effect of the magnetic field on the molten pool, and the welding quality is high.

[0015] Preferably, the titanium alloy laser narrow gap welding device further comprises a control unit, which is electrically connected to the laser, the swing laser gun, the hot wire power supply, the wire feeder, and the motion platform, respectively. This arrangement can realize automatic control of the entire welding process, with high processing efficiency and stable and reliable welding quality.

[0016] Preferably, the second direction is arranged perpendicular to the first direction. This arrangement can maximize the coverage of the groove formed by the light beam generated by the swinging laser gun on the workpiece to be welded, and the welding quality is high.

[0017] Preferably, the swing amplitude of the light beam along the second direction is A, and the width of the groove is B, wherein φ+3mm≤A≤B-3mm, wherein φ is the diameter of the welding wire and has a value of 1.6-2.4mm.

[0018] The present invention also provides a titanium alloy laser narrow gap welding method, using the titanium alloy laser narrow gap welding device mentioned above, comprising:

[0019] S1. Processing the workpiece to be welded and forming a groove with a slope of less than 5°, and limiting and fixing the workpiece to be welded to the motion platform;

[0020] S2, conveying a welding wire into the groove, applying an alternating current of 100-150A to the welding wire using a conductive nozzle, wherein the welding wire is a thick-core cable welding wire and the wire feeding speed is 1500-4000 mm / min, and controlling the motion platform to move along the first direction at a speed of 200-1000 mm / min;

[0021] S3, inert gas is delivered into the groove, and the light beam is controlled to swing periodically at a uniform speed along the second direction, the swing amplitude is A and φ+3mm≤A≤B-3mm, and the energy Q of the light beam is controlled to change periodically and Pb≤Q≤Pp, and the swing period and energy period are T respectively. p1 , T p2 , where T p1 =2*T p2 ; In each energy cycle, the output energy of the light beam increases from Pb to Pp within a duration of t1, maintains the output energy for a duration of t2, and then decreases from Pp to Pb within a duration of t3. The value of Pb is 2000-3000W, and the value of Pp is 3000-7000W.

[0022] The present invention adopts a thick-core cable-type welding wire with a large specific surface area as a filling material, and at the same time utilizes the hot wire effect to increase the heat absorption conditions of the welding wire and the molten pool, coordinates the spatial distribution of laser energy, and optimizes heat matching, which can fundamentally solve the above-mentioned technical problems; significantly improve the stability of the welding process quality, reduce the probability of unfused layers and side wall and the occurrence of pores, and improve welding efficiency by more than 40%.

[0023] Preferably, in step S3, t1=t3=0.5*t2=0.25*T p2 The value of Tp1 is 1 / 50-1 / 200s, and the values ​​of Pb and Pp are 3000 W and 5000 W respectively. Preferably, in step S2, the welding wire is heated to 180-280°C through the conductive nozzle.

[0024] Compared with the prior art, the titanium alloy laser narrow gap welding device and welding method described in the embodiments of the present invention have the following beneficial effects: 1) By utilizing the unique enlarged profile diameter of the thick-core cable-type welding wire and spatial energy modulation of the laser, the coupling matching of the filling metal required for the side wall and the energy required for the side wall can be achieved, thereby avoiding defects such as unfused side walls and pores in the molten pool; 2) By applying current to the welding wire for heating and utilizing the magnetic field generated by the current to disturb the molten pool, the molten pool can be periodically stirred, which is beneficial to the escape of pores and refinement of grains, thereby improving welding quality; 3) The large specific surface area of ​​the thick-core cable-type welding wire improves its laser energy efficiency, thereby effectively increasing the heated area and heated region during the melting process, thereby achieving efficient and high-quality laser narrow gap welding of titanium alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of a titanium alloy laser narrow gap welding device according to an embodiment of the present invention;

[0026] Figure 2 Schematic diagrams of the states of different welding wires in the embodiments of the present invention, (a) and (b) respectively represent schematic diagrams of a conventional solid welding wire and a φ1.6 thick-core cable-type welding wire before and after being heated;

[0027] Figure 3 A schematic diagram of a welding process using a thick-core cable-type welding wire according to an embodiment of the present invention;

[0028] Figure 4 A periodic diagram of the swing amplitude and power of the light beam according to the embodiment of the present invention;

[0029] Figure 5 This is a metallographic diagram of a weld formed by the welding method according to Example 2 of the present invention;

[0030] Figure 6 The metallographic images of welds formed by different welding processes, (a) and (b) represent the metallographic structures formed by Example 3 and Comparative Example 1, respectively.

[0031] Description of reference numerals:

[0032] 1-Control unit; 2. First signal line; 3. Second signal line; 4. Third signal line; 5. Laser; 6. Optical fiber; 7. Swinging laser gun; 8. Hot wire power supply; 9. Wire feeder; 10. Conductive nozzle; 11. Connecting line; 12. Grounding line; 13. Fourth signal line; 14. Welding wire; 15. Light beam; 16. Workpiece to be welded; 17. Motion platform; 18. Control component. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. The technical features of the embodiments of the present invention can be combined with each other without conflict.

[0034] The descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0035] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] Titanium alloy is a good structural material with very broad application prospects in aerospace, vehicle engineering, mechanical engineering and other fields. Currently, there is a great demand for welding of titanium alloy medium and thick plates in many fields. The welding technology of titanium alloy has become one of the constraints on the development of industries such as aerospace, shipbuilding and marine engineering, and nuclear power engineering.

[0037] Since titanium alloys have a strong affinity for oxygen, they easily form TiO2 oxide with oxygen, resulting in poor weldability, and it is difficult to obtain satisfactory results with general welding technology. At present, thick-walled titanium alloys are usually welded using inert gas welding (TIG), electron beam welding (EBW), laser wire welding, etc. Among them, the groove processing angle of thick-walled inert gas welding (TIG) generally needs to be greater than 30°, resulting in low welding efficiency, large welding deformation and residual stress, and defects in the weld; electron beam welding (EBW) has high energy density and a large weld depth-to-width ratio, making it suitable for welding thick-walled materials, but this method needs to be carried out under vacuum conditions, and the size of the workpiece to be welded is limited by the vacuum chamber, making it difficult to achieve welding of large-sized thick-walled components;

[0038] Traditional laser narrow gap welding usually uses low-power thin wires to avoid the situation where the side walls are not fused; if the laser power or wire feeding efficiency is increased unilaterally, welding defects will occur due to welding capacity mismatch; if the wire feeding efficiency and laser energy are increased at the same time, defects such as wire binding will occur due to excessive energy concentration and excessive temperature gradient in the molten pool. Therefore, traditional titanium alloy laser narrow gap welding cannot take into account both welding energy and melting quality, and has the disadvantages of low deposition efficiency and many defects. To this end, the applicant proposes the following technical solution.

[0039] Example 1

[0040] like Figure 1 As shown, a titanium alloy laser narrow gap welding device comprises:

[0041] A motion platform 17, used for limiting and fixing the workpiece 16 to be welded and driving the workpiece 16 to be welded to move along a first direction;

[0042] A wire feeder 9, used for feeding the welding wire 14 to the narrow gap of the workpiece 16 to be welded;

[0043] A conductive nozzle 10, which is located at the outlet end of the wire feeder 9 and connected to the hot wire power supply 8, and is used to heat the welding wire 14;

[0044] The oscillating laser gun 7 is located above the motion platform 17 and connected to the laser 5, and is used to emit a light beam 15 into the narrow gap of the workpiece 16 to be welded, and the light beam 15 oscillates back and forth along the second direction.

[0045] The present invention can perform spatial energy modulation at the narrow gap of the workpiece 16 to be welded by arranging an oscillating laser gun 7, adopt a larger laser power in the side wall area close to the narrow gap, and reduce the laser power near the center of the narrow gap; at the same time, the conductive nozzle 10 is used to preheat the welding wire 14 before entering the molten pool, thereby solving the matching contradiction between the laser energy and the required melting energy of narrow gap laser welding, achieving high-quality melting under efficient wire feeding, and providing conditions for efficient and high-quality welding.

[0046] Preferably, the welding wire is a thick-core cable-type welding wire with a diameter of 1.6-2.4 mm, and its specific structure is the prior art. Since the thick-core cable-type welding wire has a large specific surface area, its efficiency in obtaining laser energy is greatly improved, which is conducive to the metal supplementation of the side wall to avoid side wall defects and achieve high-quality melting; at the same time, due to the release effect before the hot wire and the welding wire melt, its outline diameter becomes larger, avoiding the contradiction caused by the concentrated laser welding energy and the limited heating of the welding wire, thereby improving the welding quality.

[0047] During welding, the diameter of the welding wire is usually 75%-80% of the groove width; considering the limitations of laser energy and temperature spatial distribution and wire feeding stability, welding wires with a diameter of φ0.8-1.2mm are often used in existing titanium alloy laser narrow gap welding to achieve a more stable welding process. In this application, the thick core cable welding wire has good flexibility and large specific area. When the diameter is φ1.6-2.4mm, the wire can still be fed stably. The larger welding wire diameter can obtain a larger heating area, which is conducive to the efficient melting of the welding wire. In order to increase the release effect of the front diameter of the welding wire during welding (the contour diameter becomes larger), the cable welding wire is designed to have a central strand diameter larger than the circumferential strand, that is, a thick core multi-strand cable welding wire, and the central strand diameter is usually 10-20% larger than the circumferential strand. This setting can improve the diameter release effect of traditional cable welding wire, making the welding wire more efficiently and evenly heated, and at the same time, it can make it easier to transfer the metal to be melted to the side wall; at the same time, due to the thermal effect of the hot wire and the diameter release effect of the welding wire during the melting process, the contour diameter will become larger, which can not only send the metal to be melted to the side wall, but also increase the heat absorption area of ​​the welding wire, which is beneficial to the stability of the welding process. Figure 2 .

[0048] Compared with solid welding wire, thick-core cable welding wire increases the heated area on the cross section of the welding wire due to the action of the hot wire and the release action before the welding wire melts (the outline diameter becomes larger). At the same time, the specific surface area near the melting zone in the length direction of the welding wire is also increased by more than three times. The heating is more uniform and efficient, which can ensure the high-quality absorption of laser energy, avoid the contradiction caused by the concentrated laser welding energy and the limited heating of the welding wire, and improve the welding quality.

[0049] Preferably, the welding wire 14 is arranged through the conductive nozzle 10, and the conductive nozzle 10 can apply current to the welding wire 14. The 50-150A alternating current applied to the welding wire 14 can not only make up for the mismatch between the laser heat input and the required heat of the molten welding material during welding, and realize the efficient deposition of large-diameter welding wires, but also the periodically changing magnetic field generated by the alternating hot wire current can stir the molten pool, promote the flow of the molten pool, and refine the grains. The specific structure of the conductive nozzle 10 is prior art and will not be described in detail here.

[0050] Preferably, the current is alternating current, that is, the hot wire power supply 8 generates alternating current. This arrangement can effectively avoid magnetic blow phenomenon, and at the same time can increase the periodic stirring effect of the magnetic field on the molten pool, and the welding quality is high.

[0051] Preferably, the second direction is arranged perpendicular to the first direction. This arrangement enables the light beam 15 generated by the swinging laser gun 7 to cover the narrow gap of the workpiece 16 to be welded to the maximum extent, and the welding quality is high. Preferably, the swing amplitude of the light beam 15 along the second direction is A, and the width of the narrow gap is B, wherein φ+3mm≤A≤B-3mm.

[0052] As an example of the present invention, the titanium alloy laser narrow gap welding device also includes a control unit 1, and the control unit 1 is electrically connected to the laser 5, the swinging laser gun 7, the hot wire power supply 8, the wire feeder 9, and the motion platform 17 respectively. This setting can realize the automatic control of the entire welding process, with high processing efficiency and stable and reliable welding quality. As an example of the present invention, the control unit 1 is any one of an industrial computer, a single-chip microcomputer, a PC, a PLC, or a DSP, which is used to cooperate with the user to input information, match welding parameters, and send control unit and welding execution unit signals.

[0053] As an example of the present invention, the laser 5 is connected to the control unit 1 through the first signal line 2, and is used to provide a laser light source for welding; the swinging laser gun 7 is connected to the control unit 1 through the second signal line 3, and is used to realize the regulation of laser welding energy; the hot wire power supply 8 is connected to the control unit 1 through the third signal line 4, and is used to provide hot wire conditions for the conductive nozzle 10, and the motion platform 17 is connected to the control unit 1 through the fourth signal line 13, which is mainly used to move the position of the workpiece 16 to be welded during welding, and the laser 5 is connected to the swinging laser gun 7 through the optical fiber 6.

[0054] Preferably, the titanium alloy laser narrow gap welding device further comprises a control component 18, and the control component 18 is electrically connected to the motion platform 17 and the control unit 1, respectively. This arrangement can utilize the control component 18 to provide motion control for welding, and the control component 18 can be independently arranged or integrated with the control unit 1.

[0055] As an example of the present invention, the hot wire power supply 8 is connected to the conductive nozzle 10 via a connecting wire 11, and the hot wire power supply 8 is provided with a ground wire 12, and the other end of the ground wire 12 is connected to the workpiece to be welded 16. This arrangement can form a current loop, thereby ensuring that current continuously passes through the welding wire 14 to heat it.

[0056] During welding, the swinging laser gun 7 is used to control the swinging amplitude of the light beam 15, and at the same time, the energy of the light beam 15 is changed periodically with time, so as to increase the energy at the root of the side wall of the narrow gap, and appropriately reduce the energy at the center of the narrow gap to optimize the spatial distribution of energy; the welding wire 14 is continuously fed to the narrow gap of the workpiece 16 to be welded by the wire feeder 9, and when the welding wire 14, especially the thick core cable welding wire, passes through the conductive nozzle 10, a current of 50-150A is applied to it to heat it to 230±50℃, and the magnetic field generated by the current can stir the molten pool to refine the grains, ensure the temperature gradient of the molten pool and avoid defects such as pores, thereby improving the welding efficiency to achieve efficient and high-quality welding.

[0057] Example 2

[0058] A titanium alloy laser narrow gap welding method, wherein the titanium alloy is a 100 mm TA2 plate, and double-sided narrow gap groove flat welding comprises:

[0059] S1, pre-processing the workpiece 16 to be welded and forming a groove with a slope of less than 5°, limiting and fixing the workpiece 16 to be welded to the motion platform 17 and moving it along the first direction at a set speed;

[0060] S2, feeding the welding wire 14 into the groove by the wire feeder 9, the angle between the welding wire and the light beam is 15-75°, applying a current of 100A to the welding wire 14 by the conductive nozzle 10 and heating it to 230±50°C, the welding wire 14 is a thick core cable welding wire with a diameter of φ=1.6mm and the wire feeding speed is 2500mm / min;

[0061] S3, by swinging the laser gun 7, the light beam 15 is controlled to swing back and forth periodically along the second direction. Figure 3 , the swing amplitude is ±3mm, the swing frequency is 100Hz, the energy of the control beam 15 changes periodically at a frequency of 200Hz, and the duration of each cycle is T p2 , where 1 / 4*T p2 The power of beam 15 is gradually increased from 3000W to 5000W, and the power is maintained at 1 / 2T. p2 Then at 1 / 4*T p2 The power is reduced from 5000W to 3000W. Figure 4 , and at the same time, inert gas is transported into the groove.

[0062] After welding, the weld was inspected according to NB / T47013 layered radiography. No defects such as lack of fusion and pores were found. The weld quality was Grade I. The weld cross section was as follows: Figure 5 As shown by Figure 5 It can be seen that there are no defects such as interlayer or side wall unfusion and porosity in the weld, and the welding quality is excellent. Due to the laser oscillation, the laser energy is reasonably distributed between the welding wire and the side wall, which improves the stability of the welding process.

[0063] Compared with the solid welding wire with a diameter of φ1.2, the welding wire 14 of the titanium alloy laser narrow gap welding method described in the present invention has been heated to 230°C by applying current when entering the high-temperature zone of the molten pool; at the same time, the magnetic field generated by the current can disturb the molten pool to enhance the overflow effect of the pores; due to the large specific surface area of ​​the thick-core cable welding wire, its efficiency in obtaining laser energy is greatly improved; and its unique diameter release effect increases the diameter of the welding wire profile, which is beneficial to the side wall metal replenishment to avoid side wall defects and achieve grain refinement, and the deposition efficiency is improved by more than 40%.

[0064] Example 3

[0065] A titanium alloy laser narrow gap welding method, wherein the titanium alloy is a 40 mm TC4 titanium alloy test plate with a double-sided narrow gap groove, comprising:

[0066] S1, pre-processing the workpiece 16 to be welded and forming a groove with a slope of less than 5°, and fixing the workpiece 16 to be welded to the moving platform 17 and moving it along the first direction at a set speed;

[0067] S2, feeding the welding wire 14 into the groove by the wire feeder 9, the angle between the welding wire and the light beam is 45°, applying a current of 120A to the welding wire 14 by the conductive nozzle 10 and heating it to 230±50°C, the welding wire 14 is a thick core cable welding wire with a diameter of φ=1.6mm and the wire feeding speed is 3000mm / min;

[0068] S3, by swinging the laser gun 7, the light beam 15 is controlled to swing back and forth periodically along the second direction. Figure 3 , the swing amplitude is ±2mm, the swing frequency is 100Hz, the energy of the control beam 15 changes periodically at a frequency of 200Hz, and the duration of each cycle is T p2 , where 1 / 4*T p2 The power of beam 15 is gradually increased from 2000W to 4500W, and the power is maintained at 1 / 2T. p2 Then at 1 / 4*T p2 The power was reduced from 4500W to 2000W, and inert gas was supplied to the groove at the same time. A total of 14 passes were welded, and the metallographic structure was shown in Figure 6 (a).

[0069] Comparative Example 1

[0070] For the 40mm TC4 titanium alloy test plate, double-sided narrow gap grooves were opened, and the traditional φ1.2 ordinary welding wire was used for double-sided groove welding. The metallographic structure is shown in Figure 6 (b).

[0071] Depend on Figure 6 It can be seen that no defects such as incomplete fusion and micropores were found in the samples of Example 3 after welding. Compared with the traditional titanium alloy TIG narrow gap welding, the number of layers in Example 1 was reduced by 40%, and the welding efficiency was improved by 30-50%; while the samples of Example 1 had obvious micropores after welding.

[0072] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A titanium alloy laser narrow gap welding device, characterized in that: include: A motion platform (17) is used to position and fix the workpiece (16) to be welded and drive the workpiece (16) to be welded to move along a first direction; A wire feeder (9) is used to feed a welding wire (14) to the groove of the workpiece (16) to be welded, wherein the welding wire (14) is a thick-core cable-type welding wire with a diameter φ of 1.6-2.4 mm; A conductive nozzle (10), arranged at the outlet end of the wire feeder (9) and connected to a hot wire power supply (8), for heating the welding wire (14); The swinging laser gun (7) is located above the motion platform (17) and connected to the laser (5), and is used to emit a light beam (15) with periodically changing energy into the groove of the workpiece (16) to be welded, wherein the light beam (15) swings back and forth along the second direction, and the angle α formed between the first direction and the second direction is 60-120°. The swing amplitude of the light beam (15) along the second direction is A, and the width of the groove formed on the workpiece (16) to be welded is B, wherein in is the diameter of the welding wire (14) and has a value of 1.6-2.4 mm; The following welding methods are used: S1, processing the workpiece to be welded (16) to form a groove with a slope of less than 5°, and fixing the workpiece to be welded (16) to the moving platform (17) in a limited manner; S2, conveying a welding wire (14) into the groove, applying an alternating current of 100-150A to the welding wire (14) using a conductive nozzle (10), wherein the welding wire (14) is a thick-core cable welding wire and the wire feeding speed is 1500-4000 mm / min, and controlling the motion platform (17) to move along the first direction at a speed of 200-1000 mm / min; S3, delivering inert gas into the groove, and controlling the light beam (15) to periodically swing at a uniform speed along the second direction, with a swing amplitude of A and The output energy Q of the light beam (15) is controlled to change periodically and Pb≤Q≤Pp. The swing period and energy period of the light beam (15) are T p1、 T p2 , where T p1 =2*T p2 In each energy cycle, the output energy of the light beam (15) increases from Pb to Pp within a time period of t1, maintains the output energy for a time period of t2, and then decreases from Pp to Pb within a time period of t3. The value of Pb is 2000-3000W, and the value of Pp is 3000-7000W.

2. The titanium alloy laser narrow gap welding device according to claim 1, characterized in that: The welding wire (14) is arranged through the conductive nozzle (10), and the conductive nozzle (10) is capable of applying alternating current to the welding wire (14).

3. The titanium alloy laser narrow gap welding device according to claim 1, characterized in that: The hot wire power supply (8) is connected to the conductive nozzle (10) via a connecting wire (11), and a ground wire (12) is provided on the hot wire power supply (8), the other end of the ground wire (12) is connected to the workpiece (16) to be welded.

4. The titanium alloy laser narrow gap welding device according to claim 1, characterized in that: The titanium alloy laser narrow gap welding device also includes a control unit (1), and the control unit (1) is electrically connected to the laser (5), the swing laser gun (7), the hot wire power supply (8), the wire feeder (9), and the motion platform (17) respectively.

5. The titanium alloy laser narrow gap welding device according to claim 1, characterized in that: The second direction is arranged perpendicular to the first direction.

6. The titanium alloy laser narrow gap welding device according to claim 1, characterized in that: In step S3, t1=t3=0.5*t2=0.25*T p2 And T p1 The value is 1 / 50-1 / 200s, and the values ​​of Pb and Pp are 3000W and 5000W respectively.

7. The titanium alloy laser narrow gap welding device according to claim 1, characterized in that: In step S2, the conductive nozzle (10) heats the welding wire (14) to 180-280°C.

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