A gas nozzle device with variable airflow protection and a method for repairing turbine blades by wire precision laser welding using the same

Abstract

A gas nozzle device with variable airflow protection and a method for using the same to repair turbine blades with precision laser welding of wire materials, the present invention belongs to the technical field of laser welding repair of aircraft engines and gas turbine blades. It solves the problem that the protection in the existing turbine blade laser welding repair process cannot simultaneously achieve simple operation, monitor the welding process, inhibit the oxidation of molten metal, metal vapor contamination and droplet splashing, as well as the quality of irregular multi-surface laser welding protection. The device consists of two arc-shaped cylindrical shells, a protective airflow net and a sealing cover, forming a first chamber, a second chamber and a third chamber, and a plurality of gas outlets are provided on the protective airflow net; the method is as follows: 1. Clamping and setting; 2. Symmetrical fixing on both sides of the blade clamping; 3. Performing precision laser welding repair with wire materials under a protective gas hood. The present invention is a gas nozzle device with variable airflow protection and using the same to repair turbine blades with precision laser welding of wire materials.

Description

Technical Field

[0001] The invention belongs to the technical field of laser welding and repairing of aero-engine and gas turbine blades. Background Art

[0002] Currently, most turbine blades used in the aviation industry are made of directionally solidified nickel-based superalloys, which exhibit excellent creep resistance, compressive yield strength, and mechanical properties, as well as corrosion and fatigue resistance, even in high-temperature environments. The high temperatures experienced during turbine operation can cause corrosion, oxidation, thermal fatigue, and mechanical fatigue in turbine blades and nozzles. Due to the high cost of replacing turbine blades, effective repair can reduce the lifecycle cost of the engine. Therefore, various turbine blade repair procedures have been developed. Laser welding the shroud of turbine blades can increase the strength of the weld overlay, reduce costs, and achieve a more reliable connection.

[0003] In order to prevent the molten metal pool from coming into contact with active elements and being oxidized during the turbine blade welding process, and the turbine blade structure is complex and multi-faceted, a special welding shielding gas nozzle is required to add welding shielding gas. During the laser welding of blades, the molten metal droplets are protected by an inert gas (welding shielding medium), which can effectively reduce weld defects, such as: oxidation of molten metal, contamination of metal vapor, and molten droplet spatter. Improper delivery of the inert shielding gas or insufficient stability of the shielding gas flow can easily cause oxidation of the weld, which will significantly reduce the welding quality and performance. Therefore, during the laser welding of blades, the design of a flexible protection device for complex and multi-faceted surfaces is a technical difficulty in achieving efficient and high-quality welding.

[0004] The current welding protection devices can be divided into three types of protection: closed protection, off-axis side blowing and coaxial blowing. Closed protection provides a closed environment for the welding of the workpiece during the welding process, inhibiting its oxidation, but the structure of the blade is complex, and laser welding in a closed environment is difficult to operate, and it is difficult to monitor the welding process, which cannot be widely used. The off-axis side blowing protection method has a simple structure, is easy to install, and is relatively flexible, but due to the fixed output direction of the shielding gas, the consistency of the weld formation quality is not high during variable direction processing, and it is even more difficult to apply to the multi-surface of the turbine blade. Coaxial blowing protection requires the use of wire feeding to fill the metal during the blade welding process, so it is difficult to provide good welding protection for the molten metal.

[0005] In summary, the closed protection method has a good welding protection effect, but at present, due to the multi-surface structure of the blade and the limited space for wire feeding and filling metal, it is not possible to achieve efficient welding repair of the blade. Summary of the Invention

[0006] The present invention aims to solve the problems that the protection in the existing turbine blade laser welding repair process cannot simultaneously achieve simple operation, monitor the welding process, inhibit the oxidation of molten metal, metal vapor contamination and droplet splashing, as well as the quality of irregular multi-surface laser welding protection, and further provide a gas nozzle device with variable airflow protection and a method for using the same to perform wire precision laser welding to repair turbine blades.

[0007] A gas nozzle device for variable airflow protection, which consists of two arc-shaped columnar shells, a protective airflow net and a sealing cover;

[0008] The inner wall of the arc-shaped cylindrical shell is sequentially provided with three grooves along the circumferential direction, the upper end surfaces and inner side surfaces of the three grooves are open structures, a sealing cover is provided on the upper end surface of the arc-shaped cylindrical shell, and a protective air flow net is provided on the inner wall surface of the arc-shaped cylindrical shell, and the inner wall of the arc-shaped cylindrical shell, the sealing cover and the protective air flow net form a first chamber, a second chamber and a third chamber; the protective air flow net is provided with a plurality of gas outlets in an array at positions corresponding to the first chamber, the second chamber and the third chamber;

[0009] The first chamber, the second chamber and the third chamber are provided with gas inlets at the bottom, and multiple gas flow channel partitions are provided longitudinally and parallelly inside.

[0010] The two arc-shaped cylindrical shells have the same structure and are symmetrically arranged.

[0011] The beneficial effects of the present invention are:

[0012] The present invention utilizes different chambers to form laminar flows with different flow rates. Based on the fact that the shielding gas input flow rates of the first and third chambers are the same, the shielding gas input flow rate ratio of the first chamber to the second chamber is (0.9-1.2):1, and the sector angle corresponding to the second chamber is larger than that of the first and third chambers, which results in the second chamber having a larger volume than the first and third chambers. This results in high-speed shielding gas output on both sides and stable and slow shielding gas output inside. The airflow on both sides forms a protective layer, and the internal airflow protects the molten metal during the laser welding process to prevent oxidation, forming a quasi-enclosed protection method. This provides a protection method for laser wire feeding welding repair of multiple blade shroud surfaces. The specific advantages are as follows:

[0013] 1. The device of the present invention can achieve full coverage of the protective gas during the laser welding process of repairing the multi-surface parts of the blade. The chamber structure forms a gas hood with low internal pressure and high pressure on both sides through different output flow rates of gas. At the same time, it cooperates with the fairing to accurately control the protection area of ​​the protective gas, effectively suppressing the oxidation of the molten metal during the laser welding process.

[0014] 2. The device does not interfere with the welding process, offers a wider protection range than side-by-side systems, and provides ample space between the shielding gas nozzles on both sides, facilitating swinging during laser welding and ensuring efficient wire delivery. This provides quasi-sealed protection for precision-repaired blades using laser fuse welding. This approach reduces oxidation of the molten metal in the overlay layer, spatter during welding, and porosity in the weld seam, while maintaining the operating space for the wire feeder and laser head.

[0015] 3. The device of the present invention has good protection effect. The various parts of the laser welding shielding gas nozzle are tightly connected, with good sealing and no air leakage. The shielding gas flows into the cavity through the air inlet and flows out from the shielding gas outlet, achieving the effect of overall protection and obtaining a surfacing layer with good forming quality.

[0016] 4. The device of the present invention is easy to install and disassemble, has high adaptability, is convenient to operate, can monitor the welding process, can be installed on both sides of the repaired blade, and is also suitable for protection during welding of other multi-shaped surfaces with high adaptability.

[0017] Figures in the specification

[0018] Figure 1 This is a schematic diagram of the overall structure of the gas nozzle device for variable airflow protection of the present invention;

[0019] Figure 2 A front view of the gas nozzle device for variable airflow protection according to the present invention;

[0020] Figure 3 This is a diagram showing the interior of a chamber of a gas nozzle device for variable airflow protection according to the present invention;

[0021] Figure 4 A diagram showing the positional relationship between the protective airflow network and the chamber of the gas nozzle device for variable airflow protection of the present invention;

[0022] Figure 5 A schematic diagram showing the angles between chambers of a gas nozzle device for variable airflow protection according to Example 1;

[0023] Figure 6 A schematic structural diagram of a positioning device for a gas nozzle device for variable airflow protection according to the present invention;

[0024] Figure 7 To compare the surface and cross-sectional morphologies of the DZ125 alloy blade cladding layer produced by laser wire feeding welding under side-axis protection;

[0025] Figure 8 The surface and cross-sectional morphology of the DZ125 alloy blade cladding layer produced by laser wire feeding welding under variable airflow sealed protection in Example 1;

[0026] Among them, 1-arc-shaped cylindrical shell; 2-fairing; 3-protective airflow net; 4-positioning device; 5-turbine blade to be repaired; 6-wire feed conductive nozzle and welding wire; 7-hose; 8-sealing cover; 9-gas inlet; 10-first chamber; 11-second chamber; 12-third chamber; 13-gas flow channel partition plate. DETAILED DESCRIPTION

[0027] Specific implementation method 1, combined with Figures 1 to 4 6. Specific description: This embodiment is a gas nozzle device for variable airflow protection, which consists of two arc-shaped cylindrical shells 1, a protective airflow net 3 and a sealing cover 8;

[0028] The inner wall of the arc-shaped cylindrical shell 1 is provided with three grooves in sequence along the circumferential direction, and the upper end surfaces and inner side surfaces of the three grooves are open structures. A sealing cover 8 is provided on the upper end surface of the arc-shaped cylindrical shell 1, and a protective airflow net 3 is provided on the inner wall surface of the arc-shaped cylindrical shell 1. The inner wall of the arc-shaped cylindrical shell 1, the sealing cover 8 and the protective airflow net 3 form a first chamber 10, a second chamber 11 and a third chamber 12; the protective airflow net 3 is provided with a plurality of gas outlets in an array at positions corresponding to the first chamber 10, the second chamber 11 and the third chamber 12;

[0029] The first chamber 10, the second chamber 11 and the third chamber 12 are provided with a gas inlet 9 at the bottom, and a plurality of gas flow channel partition plates 13 are provided longitudinally and parallelly inside.

[0030] The two arc-shaped cylindrical shells 1 have the same structure, and the two arc-shaped cylindrical shells 1 are symmetrically arranged.

[0031] The beneficial effects of this embodiment are:

[0032] This embodiment utilizes different chambers to form laminar flows with different flow rates. The shielding gas input flow rates of the first and third chambers are the same, and the shielding gas input flow rate ratio between the first and second chambers is (0.9-1.2):1. Furthermore, the sector angle corresponding to the second chamber is larger than that of the first and third chambers, resulting in a larger volume of the second chamber than the first and third chambers. This results in high-speed shielding gas output on both sides and stable, slow shielding gas output inside. The airflow on both sides forms a protective layer, and the internal airflow protects the molten metal during laser welding, preventing oxidation, forming a quasi-enclosed protection method. This provides a protection method for laser wire feeding welding repair of multiple blade shroud surfaces. The specific advantages are as follows:

[0033] 1. The device of this embodiment can achieve full coverage of the shielding gas during the laser welding process of repairing the multi-surface parts of the blade. The chamber structure forms a gas hood with low internal pressure and high pressure on both sides through gases with different output flow rates. At the same time, it cooperates with the fairing to accurately control the protection area of ​​the shielding gas, effectively suppressing the oxidation of the molten metal during the laser welding process.

[0034] 2. This device does not interfere with the welding process and offers a wider protection range than a side-axis device. Ample space is left between the shielding gas nozzles on both sides, facilitating swinging during laser welding and ensuring efficient wire delivery. This provides quasi-sealed protection for precision-repaired blades using laser fuse welding. This approach reduces oxidation of the molten metal in the overlay layer, spatter during welding, and porosity in the weld, while maintaining the operating space for the wire feeder and laser head.

[0035] 3. The device of this embodiment has good protection effect. The various parts of the laser welding shielding gas nozzle are tightly connected, with good sealing and no air leakage. The shielding gas flows into the cavity through the air inlet and flows out from the shielding gas outlet, achieving the effect of overall protection and obtaining a surfacing layer with good forming quality.

[0036] 4. The device of this embodiment is easy to install and disassemble, has high adaptability, is convenient to operate, can monitor the welding process, can be installed on both sides of the repaired blade, and is also suitable for protection during welding of other multi-surfaces with high adaptability.

[0037] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the sector angle of the arc-shaped columnar housing 1 is 140° to 155°. Other aspects are the same as specific embodiment 1.

[0038] Specific embodiment 3: This embodiment differs from specific embodiment 1 or 2 in that the first chamber 10 and the third chamber 12 have the same structure. Other aspects are the same as specific embodiment 1 or 2.

[0039] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the first chamber 10 and the third chamber 12 have the same structure. Other aspects are the same as specific embodiments 1 to 3.

[0040] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the second chamber 11 is disposed in the middle of the arc-shaped cylindrical housing 1, and the first chamber 10 and the third chamber 12 are symmetrically disposed on both sides of the second chamber 11. Other features are the same as specific embodiments 1 to 4.

[0041] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the diameters of the plurality of gas outlets are all 2 mm to 4 mm. Other aspects are the same as specific embodiments 1 to 5.

[0042] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the two arc-shaped cylindrical housings 1 are disposed on the positioning device 4 and the gas inlet 9 is connected to the hose 7. Other features are the same as specific embodiments 1 to 6.

[0043] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that a fairing 2 is provided on the sealing cover 8. The rest is the same as specific embodiments 1 to 7.

[0044] Specific embodiment 9: This embodiment provides a method for repairing turbine blades by wire precision laser welding using a gas nozzle device with variable airflow protection, which is carried out in the following steps:

[0045] 1. Clamp the turbine blade to be repaired and set the laser welding path and defocus amount;

[0046] Second, the two arc-shaped cylindrical shells 1 of the gas nozzle device with variable airflow protection are fixed symmetrically on both sides of the blade clamp through the positioning device 4, and an operating space for the wire feeding conductive nozzle and welding wire is left between the two arc-shaped cylindrical shells 1;

[0047] 3. The shielding gas input flow rates of the first chamber 10 and the third chamber 12 are set to be the same, and both are 10L / min to 25L / min. The shielding gas input flow rate ratio of the first chamber (10) to the second chamber (11) is (0.9 to 1.2):1. The shielding gas is guided through the chamber and the gas flow channel and then sent out to form a shielding gas hood. The shielding gas hood covers the laser welding area of ​​the blade. Wire precision laser welding repair is performed under the shielding gas hood, thus completing the method for wire precision laser welding repair of turbine blades.

[0048] After the blade workpiece is clamped, the robot sets the path and defocus amount. The two arc-shaped cylindrical shells 1 are symmetrically fixed on both sides of the blade to be repaired by the positioning device 4, completely covering the blade welding area. At the same time, the two arc-shaped cylindrical shells 1 leave enough operating space for the wire feeding conductive nozzle and the welding wire 6. The shielding gas nozzle device is coaxial with the laser head, so that the laser can directly reach the surface of the workpiece to be welded during the repair process. The gas nozzle connector introduces the shielding gas through the hose 7. The shielding gas passes through the gas flow channel and is finally ejected through the shielding gas flow net 3, forming a shielding gas chamber with a small blowout airflow in the second chamber 11 and a large blowout airflow in the first chamber 10 and the third chamber 12, thereby realizing quasi-sealed protection of variable airflow. At the same time, the presence of the fairing 2 above the shielding gas nozzle reduces gas waste and forms a complete shielding gas chamber.

[0049] Specific embodiment 10: This embodiment differs from specific embodiment 9 in that the gas nozzle device for variable airflow protection described in step 2 is coaxial with the laser head. Other aspects are the same as specific embodiment 9.

[0050] The following examples are used to verify the beneficial effects of the present invention:

[0051] Example 1:

[0052] A gas nozzle device for variable airflow protection, which consists of two arc-shaped cylindrical shells 1, a protective airflow net 3 and a sealing cover 8;

[0053] The inner wall of the arc-shaped cylindrical shell 1 is provided with three grooves in sequence along the circumferential direction, and the upper end surfaces and inner side surfaces of the three grooves are open structures. A sealing cover 8 is provided on the upper end surface of the arc-shaped cylindrical shell 1, and a protective airflow net 3 is provided on the inner wall surface of the arc-shaped cylindrical shell 1. The inner wall of the arc-shaped cylindrical shell 1, the sealing cover 8 and the protective airflow net 3 form a first chamber 10, a second chamber 11 and a third chamber 12; the protective airflow net 3 is provided with a plurality of gas outlets in an array at positions corresponding to the first chamber 10, the second chamber 11 and the third chamber 12;

[0054] The gas inlet 9 is provided at the bottom of the first chamber 10, the second chamber 11 and the third chamber 12, and three gas flow channel partition plates 13 are longitudinally and parallelly provided inside the first chamber 10, the second chamber 11 and the third chamber 12;

[0055] The two arc-shaped cylindrical shells 1 have the same structure and are symmetrically arranged;

[0056] The arc-shaped cylindrical housing 1 has a sector angle of 150°, a radius of 150 mm, and a height of 200 mm;

[0057] The first chamber 10 and the third chamber 12 have the same structure;

[0058] The sector angles of the first chamber 10 and the third chamber 12 are both 30°; the sector angle of the second chamber 11 is 50°; and the sector angles of the intervals between the first chamber 10, the third chamber 12 and the second chamber 11 are all 5°; the sector angle of the interval between one side of the first chamber 10 and one side of the adjacent arc-shaped cylindrical housing 1 is 15°;

[0059] The second chamber 11 is disposed in the middle of the arc-shaped cylindrical housing 1 , and the first chamber 10 and the third chamber 12 are symmetrically disposed on both sides of the second chamber 11 .

[0060] The diameters of the multiple gas outlets are all 3 mm, and the protective air flow net 3 corresponding to the positions of the first chamber 10 and the third chamber 12 are arrayed with 24 rows × 10 columns of gas outlets, and the protective air flow net 3 corresponding to the position of the second chamber 11 is arrayed with 24 rows × 16 columns of gas outlets.

[0061] The two arc-shaped cylindrical shells 1 are arranged on the positioning device 4. The positioning device 4 has two threaded holes with a diameter of 4 mm, which are connected to the arc-shaped cylindrical shell 1 by bolts; the gas inlet 9 is connected to the hose 7, and the diameter of the hose 7 is 8 mm.

[0062] The sealing cover 8 is provided with a fairing 2; the fairing 2 and the protective airflow net 3 are fixed to the arc-shaped columnar housing 1 using bolts through threaded holes with a diameter of 2 mm.

[0063] The method for repairing turbine blades by wire precision laser welding using the above-mentioned variable airflow protection gas nozzle device is carried out in the following steps:

[0064] 1. Clamp the turbine blade to be repaired and set the laser welding path and defocus amount;

[0065] Second, the two arc-shaped cylindrical shells 1 of the gas nozzle device with variable airflow protection are fixed symmetrically on both sides of the blade clamp through the positioning device 4, and an operating space for the wire feeding conductive nozzle and welding wire is left between the two arc-shaped cylindrical shells 1;

[0066] 3. The shielding gas input flow rates of the first chamber 10 and the third chamber 12 are set to be the same, both at 15 L / min, and the shielding gas input flow rate of the second chamber 11 is 15 L / min. The shielding gas is guided through the chamber and the gas flow channel and then sent out to form a shielding gas hood. The shielding gas hood covers the laser welding area of ​​the blade. Under the conditions of the shielding gas hood, a laser power of 650 W, a welding speed of 0.06 m / min and a wire feeding speed of 0.72 m / min, wire precision laser welding repair is performed using welding wire, thereby completing a method for wire precision laser welding repair of turbine blades.

[0067] The gas nozzle device for variable airflow protection described in step 2 is coaxial with the laser head.

[0068] The material of the turbine blade to be repaired in step 1 is DZ125; the material of the welding wire in step 2 is CoCrW, and the CoCrW is composed of 29.64% Cr, 1.15% C, 4.12% W and the balance Co by mass.

[0069] Comparative Experiment: This comparative experiment differs from Example 1 in that, under the same laser welding process parameters, side-shaft protected laser welding is used, and the shielding gas flow rate is 15 L / min. Other conditions are the same as Example 1.

[0070] Figure 7 To compare the surface and cross-sectional morphologies of the DZ125 alloy blade cladding layer produced by laser wire feeding welding under side-axis protection; Figure 8 This is the surface and cross-sectional morphology of the DZ125 alloy blade surfacing layer produced by laser wire feeding welding under variable airflow type closed protection in Example 1. Figure 7 and Figure 8The morphology of the weld overlay layer of a high-temperature alloy turbine blade was investigated using both side-shaft protected laser welding and laser welding with a variable-flow shielding gas nozzle under identical laser welding process parameters. It can be seen that under side-shaft protection, the laser fuse was welded and repaired on multiple blade surfaces at a shielding gas flow rate of 15 L / min. The weld overlay surface lacked a bright white metallic luster and was severely oxidized. The base material exhibited a blue color due to heat accumulation, resulting in discontinuous weld overlay formation and severe molten metal spatter during welding. Observation of the cross-sectional morphology of the weld overlay revealed numerous inclusions, uneven microstructure distribution, and the presence of defects such as pores. Under the same process parameters, a variable airflow quasi-closed protection method is adopted. The shielding gas input flow rates of the first, second and third chambers are all 15L / min, and the fan angle corresponding to the second chamber is larger than that of the first and third chambers, which leads to the volume of the second chamber being larger than that of the first and third chambers. Therefore, a gas shield with high-speed shielding gas output on both sides and stable and slow shielding gas output inside is formed. The surface of the weld overlay layer presents a bright white metallic luster, the forming is continuous, the oxidation of the base material is effectively suppressed, there is no spatter during welding, and the protection effect is excellent compared with the side-axis protection. At the same time, the cross-section of the weld overlay layer is uniform, without defects such as pores and inclusions, which greatly improves the stability of the molten droplet transition during turbine blade welding, improves the welding quality of multi-surface components, and greatly improves the welding efficiency, which can be increased by more than 2 times.

Claims

1. A gas nozzle device for variable airflow protection, characterized in that It consists of two arc-shaped cylindrical shells (1), a protective airflow net (3) and a sealing cover (8); The inner wall of the arc-shaped cylindrical shell (1) is provided with three grooves in sequence along the circumferential direction, and the upper end surfaces and inner side surfaces of the three grooves are open structures. A sealing cover (8) is provided on the upper end surface of the arc-shaped cylindrical shell (1), and a protective air flow net (3) is provided on the inner wall surface of the arc-shaped cylindrical shell (1). The inner wall of the arc-shaped cylindrical shell (1), the sealing cover (8) and the protective air flow net (3) form a first chamber (10), a second chamber (11) and a third chamber (12); the protective air flow net (3) is provided with a plurality of gas outlets in an array at positions corresponding to the first chamber (10), the second chamber (11) and the third chamber (12); The first chamber (10), the second chamber (11), and the third chamber (12) are provided with a gas inlet (9) at the bottom, and a plurality of gas flow channel partition plates (13) are provided longitudinally and parallelly inside. The two arc-shaped cylindrical shells (1) have the same structure, and the two arc-shaped cylindrical shells (1) are symmetrically arranged; The sector angles of the first chamber (10) and the third chamber (12) are both 25° to 35°; the sector angle of the second chamber (11) is 40° to 60°; The second chamber (11) is arranged in the middle of the arc-shaped cylindrical housing (1), and the first chamber (10) and the third chamber (12) are symmetrically arranged on both sides of the second chamber (11); The shielding gas input flow rates of the first chamber (10) and the third chamber (12) are set to be the same, and the shielding gas input flow rate ratio of the first chamber (10) to the second chamber (11) is (0.9-1.2):

1.

2. A gas nozzle device for variable airflow protection according to claim 1, characterized in that The sector angle of the arc-shaped columnar housing (1) is 140° to 155°.

3. A gas nozzle device for variable airflow protection according to claim 1, characterized in that The first chamber (10) and the third chamber (12) have the same structure.

4. The gas nozzle device for variable airflow protection according to claim 1, characterized in that The diameters of the multiple gas outlets are all 2mm to 4mm.

5. The gas nozzle device for variable airflow protection according to claim 1, characterized in that The two arc-shaped columnar housings (1) are arranged on the positioning device (4); the gas inlet (9) is connected to the hose (7).

6. The gas nozzle device for variable airflow protection according to claim 1, characterized in that A fairing (2) is provided on the sealing cover (8).

7. A method for repairing turbine blades by wire precision laser welding using a gas nozzle device with variable airflow protection as claimed in claim 1, characterized in that It is carried out in the following steps:

1. Clamp the turbine blade to be repaired and set the laser welding path and defocus amount; Second, the two arc-shaped cylindrical shells (1) of the gas nozzle device with variable airflow protection are fixed symmetrically on both sides of the blade clamp through the positioning device (4), and an operating space for the wire feeding conductive nozzle and the welding wire is left between the two arc-shaped cylindrical shells (1); 3. The shielding gas input flow rates of the first chamber (10) and the third chamber (12) are set to be the same, and both are 10L / min~25L / min. The shielding gas input flow rate ratio of the first chamber (10) to the second chamber (11) is (0.9~1.2):

1. The shielding gas is guided through the chamber and the gas flow channel and then sent out to form a shielding gas hood. The shielding gas hood covers the laser welding area of ​​the blade. Wire precision laser welding repair is performed under the shielding gas hood, thereby completing the method of wire precision laser welding repair of turbine blades.

8. The method for repairing turbine blades by wire precision laser welding using a gas nozzle device with variable airflow protection according to claim 7, characterized in that The gas nozzle device for variable airflow protection described in step 2 is coaxial with the laser head.

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