Titanium alloy surface laser ultrasonic composite cleaning reinforced welding method

Abstract

The invention provides a titanium alloy surface laser ultrasonic composite cleaning reinforced welding method, belongs to the technical field of non-ferrous metal surface cleaning and modification, and aims to solve the problems of poor welding seam quality and poor surface corrosion resistance, fatigue resistance and the like in the titanium alloy welding process. The cleanliness of the surfaces of components, welding grooves and the like is improved, and the production and machining efficiency is improved. In the fusion welding process, ultrasonic excitation of a high-energy beam is applied to the back face of a weld joint, the grain size of the weld joint is refined, the mechanical property of a connector is improved, rotating ultrasonic waves are applied to the surface of a component and the weld joint, the component and the surface of the weld joint generate plastic deformation, and the overall performance of the component and the surface of the weld joint is improved. The high temperature resistance, the corrosion resistance, the fatigue resistance and the like are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal surface cleaning and modification, and specifically discloses a method for laser-ultrasonic composite cleaning and enhanced welding of a titanium alloy surface. Background Art

[0002] Titanium and titanium alloys have high strength, high temperature resistance and good corrosion resistance, and have broad application prospects in aerospace, underwater equipment and nuclear industry. The surface and weld cleanliness, surface stress state and microstructure of titanium and titanium alloys have an important influence on the engineering application of titanium and titanium alloys.

[0003] During the welding process of titanium and titanium alloys, high requirements are placed on the cleanliness of the surface and the quality of the weld. Surface oxidation is very likely to occur during the heating process, and the residual oil and rust on the surface can easily cause microscopic defects such as inclusions and pores inside the weld. At the same time, the weld position belongs to the cast structure, which leads to a decrease in its mechanical properties, which is usually lower than the strength of the original parent material, and becomes the weak point of the entire component product. How to improve the surface quality of titanium and titanium alloys during the processing / welding process and improve the mechanical properties of the weld will have a positive role in promoting the application of titanium and titanium alloy component products. Summary of the invention

[0004] In view of the high requirements for weld and surface quality during the use of titanium alloy materials in the fields of corrosion resistance, high temperature resistance and fatigue resistance, the present invention provides a method for laser ultrasonic composite cleaning and strengthening welding of titanium alloy surface, which uses pulsed laser to clean the working surface (i.e., the front side) and groove position of the titanium alloy test plate to remove surface impurities, applies ultrasonic excitation on the back side of the titanium alloy test plate at both sides of the weld to refine the grain structure of the weld, accelerates the overflow of internal gas, impurities, etc., and thus improves the mechanical properties of the weld, and performs ultrasonic impact strengthening on the working surface including the weld through rotating ultrasound, thereby improving the overall performance and surface performance of the titanium alloy component, and has broad application prospects in the field of non-ferrous metal welding and surface modification.

[0005] The above-mentioned titanium alloy surface laser ultrasonic composite cleaning and strengthening welding method comprises the following steps:

[0006] S1, Preparation of titanium alloy test plate

[0007] Processing welding grooves on titanium alloy test plates;

[0008] S2, using pulsed laser to clean the front and groove of titanium alloy test plate

[0009] S3, titanium alloy test plate welding

[0010] The welding is performed by using metal arc gas shielded welding, and ultrasonic excitation is applied to the back side of the titanium alloy test plate at the positions on both sides of the weld;

[0011] S4, Titanium alloy test plate and surface treatment

[0012] The titanium alloy test plate and the front side of the weld were subjected to rotary ultrasonic strengthening treatment.

[0013] In step S1, the blunt edge of the titanium alloy test plate is 1.5 mm, and the single-side groove angle is 30°;

[0014] In step S2, the pulse laser power is 150W, the speed is 6mm / s, the frequency is 23KHz, the pulse width is 500ns, and the scanning spot is rectangular with a size of 100mm×3mm;

[0015] In step S3, the diameter of the welding wire is 1.2 mm, 99.99% argon gas is used for protection, the gas flow rate is 25-30 L / min, the welding current is 180-240 A, the welding speed is 0.3 m / min, the arc length is corrected by 30%, and the welding wire extension length is 15 mm;

[0016] The ultrasonic frequency was 20kHz and the ultrasonic power was 4kW;

[0017] In step S4, the rotation speed is 25 r / min, the moving speed is 1 mm / s, the downward force is 0.2 mm, the ultrasonic frequency is 20 kHz, and the ultrasonic power is 4 kW.

[0018] Steps S2-S4 are performed using a laser ultrasonic composite cleaning and enhanced welding system;

[0019] The laser ultrasonic composite cleaning and strengthening welding system comprises a welding robot, an ultrasonic excitation table, a laser cleaning device and a rotating ultrasonic strengthening device; the welding robot is used for welding a titanium alloy test plate; the ultrasonic excitation table comprises a supporting table, a substrate workbench, a first high-energy ultrasonic generator, a first transducer and a first horn; the first high-energy ultrasonic generator is connected to the first transducer; the first transducer is movably mounted on the supporting table; the bottom end of the first horn is connected to the top end of the first transducer, and the top end is connected to the substrate workbench; the titanium alloy test plate processed by step S1 is placed on the substrate workbench; the laser cleaning device and the rotating ultrasonic strengthening device are located above the substrate workbench and can move on the surface of the titanium alloy test plate; the rotating ultrasonic strengthening device comprises a rotating driving mechanism, a second high-energy ultrasonic generator, a second transducer, a second horn, a tool head and a ball bearing; the second high-energy ultrasonic generator is connected to the second transducer; the second transducer is driven to rotate by the rotating driving mechanism; the top end of the second horn is connected to the bottom end of the second transducer, and the bottom end is connected to the tool head; a ball bearing is rotatably mounted on the bottom end of the tool head.

[0020] The welding robot includes a robotic arm, a welding gun, a welding machine, welding wire, a wire feeding mechanism and a shielding gas cylinder; the welding gun is installed at the end of the robotic arm; the welding machine provides power for the welding gun; the welding wire is loaded into the welding gun through the wire feeding mechanism; the shielding gas cylinder is filled with shielding gas and is connected to the welding gun through a gas pipe; a pressure gauge is installed on the shielding gas cylinder.

[0021] An inverted T-slot is arranged on the support platform; the ultrasonic excitation platform also includes an inverted T-rod, a connecting plate and a locking nut; the bottom end of the inverted T-rod is movably inserted in the inverted T-slot; inverted T-rods are symmetrically arranged on both sides of the first transducer, the connecting plate is sleeved on the first transducer and the inverted T-rods on both sides of the first transducer, the locking nut is installed on the inverted T-rod to press the connecting plate, and the first transducer is suspended in the air through the inverted T-rod, the connecting plate and the locking nut.

[0022] The support table is supported by legs.

[0023] The laser ultrasonic composite cleaning and strengthening welding system also includes a clamping frame; the rotary ultrasonic strengthening device also includes a shell and a bearing; the shell is fixed on the clamping frame, the second transducer and the second amplitude transformer are rotatably installed in the shell through the bearing, and the tool head extends from the bottom end of the shell; the rotary driving mechanism includes a motor; the motor is fixed on the clamping frame to drive the second transducer to rotate; the laser cleaning device is fixed on the clamping frame; the clamping frame drives the laser cleaning device and the rotary ultrasonic strengthening device to move on the surface of the titanium alloy test plate.

[0024] The clamping frame includes a clamping beam, a first vertical beam, a first horizontal beam, a second vertical beam and a second horizontal beam; the clamping beam, the first horizontal beam and the second horizontal beam are parallel to the substrate workbench, and the first vertical beam and the second vertical beam are perpendicular to the substrate workbench; the first horizontal beam is fixed on the first vertical beam; the clamping beam and the first horizontal beam are connected through the second vertical beam; the second horizontal beam is fixed on the second vertical beam; the laser cleaning device and the housing are fixed on the clamping beam; the motor is fixed on the second horizontal beam; the rotation drive mechanism also includes a driving wheel installed on the motor output shaft, a driven wheel installed on the top of the second transducer, and a synchronous belt connecting the driving wheel and the driven wheel.

[0025] The laser ultrasonic composite cleaning and enhanced welding system also includes a control cabinet; the control cabinet is provided with a power switch, a power switch indicator light, a robotic arm controller, a robotic arm controller indicator light, a welding power supply controller, a welding power supply controller indicator light, a wire feeding mechanism controller, a wire feeding mechanism controller indicator light, an ultrasonic excitation table controller, an ultrasonic excitation table controller indicator light, a laser cleaning controller, a laser cleaning controller indicator light, an ultrasonic enhancement controller, an ultrasonic enhancement controller indicator light, a motor controller, a motor controller indicator light, an emergency button and an emergency button indicator light; the robotic arm and the control cabinet are connected through a first connection line; the welding machine and the control cabinet are connected through a second connection line; the first high-energy ultrasonic generator and the first transducer are connected through a third connection line, and the first high-energy ultrasonic generator and the control cabinet are connected through a fourth connection line.

[0026] Compared with the prior art, the present invention has the following beneficial effects.

[0027] The present invention aims at the problems of poor weld quality and poor surface corrosion resistance, fatigue resistance and other properties in the welding process of non-ferrous metals such as titanium alloys. The pulsed laser is used as a surface cleaning heat source to improve the cleanliness of the surface of the titanium alloy test plate, the welding groove and other surfaces, and improve the production and processing efficiency. In the melting welding process, a high-energy beam of ultrasonic excitation is applied to the back of the weld to refine the weld grain size and improve the mechanical properties of the joint. Rotating ultrasonic waves are applied to the titanium alloy test plate and the weld surface to cause plastic deformation of the titanium alloy test plate and the weld surface, thereby improving the overall performance of the component and the weld surface, and improving its high temperature resistance, corrosion resistance and fatigue resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 This is a schematic diagram of the laser ultrasonic composite cleaning and enhanced welding system;

[0030] Figure 2 is a schematic diagram of an ultrasonic excitation platform;

[0031] Figure 3 is a schematic diagram of a laser cleaning device;

[0032] Figure 4 Schematic diagram of the rotary ultrasonic strengthening device.

[0033] In the figure: 1.1-robot arm; 1.2-welding gun; 1.3-welding machine; 1.4-welding wire; 1.5-wire feeding mechanism; 1.6-shielding gas cylinder; 1.7-gas pipe; 1.8-pressure gauge;

[0034] 2.1-support table; 2.2-substrate workbench; 2.3-first high-energy ultrasonic generator; 2.4-first transducer; 2.5-first amplitude transformer; 2.6-support leg; 2.7-inverted T-slot; 2.8-inverted T-bar; 2.9-connecting plate; 2.10-fastening nut;

[0035] 3-Laser cleaning device;

[0036] 4.1-second transducer; 4.2-second amplitude transformer; 4.3-tool head; 4.4-ball bearing; 4.5-housing; 4.6-bearing; 4.7-support plate; 4.8-motor; 4.9-driving wheel; 4.10-driven wheel; 4.11-synchronous belt;

[0037] 5-control cabinet; 5.1-power switch; 5.2-power switch indicator light; 5.3-robotic arm controller; 5.4-robotic arm controller indicator light; 5.5-welding power supply controller; 5.6-welding power supply controller indicator light; 5.7-wire feeder mechanism controller; 5.8-wire feeder mechanism controller indicator light; 5.9-ultrasonic excitation table controller; 5.10-ultrasonic excitation table controller indicator light; 5.11-laser cleaning controller; 5.12-laser cleaning controller indicator light; 5.13-ultrasonic enhancement controller; 5.14-ultrasonic enhancement controller indicator light; 5.15-motor controller; 5.16-motor controller indicator light; 5.17-emergency button; 5.18-emergency button indicator light;

[0038] 6.1-clamping beam; 6.2-first vertical beam; 6.3-first horizontal beam; 6.4-second vertical beam; 6.5-second horizontal beam;

[0039] 7-first connecting line; 8-second connecting line; 9-third connecting line; 10-fourth connecting line; 101-titanium alloy test plate; 102-weld. DETAILED DESCRIPTION

[0040] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Laser is widely used as a heat source in the surface treatment of materials, such as laser surface rust removal and strengthening. When the laser acts on the metal surface, it can quickly evaporate and peel off the oil, rust, and rust layer, thereby cleaning and strengthening the metal surface. Compared with laser surface treatment, ultrasound has stronger penetration ability. In addition to strengthening the metal surface, it can also refine the grains during the metal solidification process, promote the overflow of impurities, pores and other defects inside the metal, reduce defects, and improve product quality. Based on the above theory, the present invention proposes a method for laser ultrasonic composite cleaning and strengthening welding of titanium alloy surface.

[0042] This method is aimed at the problems that the welding groove needs to be cleaned during the welding process, and the weld is prone to defects that reduce the mechanical properties of the welded joint. During the welding process, a laser cleaning device is set at the front end of the welding heat source, a rotating ultrasonic strengthening device is set at the rear end close to the welding heat source, and an ultrasonic excitation table is set at the back of the weld. While cleaning the titanium alloy plate and the surface quality of the groove, the ultrasonic excitation effect improves the strength of the weld, saves work time, and improves production efficiency and welding quality. This method has broad application prospects in the field of ferrous metal and non-ferrous metal welding.

[0043] The chemical materials used are: titanium alloy plate, titanium alloy welding wire, argon gas, and sandpaper, and the combined preparation amounts are as follows: grams and millimeters are used as the units of measurement.

[0044] Titanium alloy plate: TC4 2 pieces 300mm×150mm×6mm

[0045] Titanium alloy welding wire: TC4 5Kg

[0046] Argon: 1 bottle Sandpaper: 400 mesh, 2 sheets, 300mm×200mm×0.5mm

[0047] Welding is performed using a laser ultrasonic hybrid cleaning enhanced welding system.

[0048] The laser ultrasonic composite cleaning and strengthening welding system comprises a welding robot, an ultrasonic excitation table, a laser cleaning device 3, a rotary ultrasonic strengthening device, a control cabinet 5 and a clamping frame.

[0049] The welding robot is used for welding titanium alloy test plates. The welding robot includes a mechanical arm 1.1, a welding gun 1.2, a welding machine 1.3, a welding wire 1.4, a wire feeding mechanism 1.5 and a shielding gas cylinder 1.6; the welding gun 1.2 is installed at the end of the mechanical arm 1.1; the welding machine 1.3 provides power to the welding gun 1.2; the welding wire 1.4 is loaded into the welding gun 1.2 through the wire feeding mechanism 1.5; the shielding gas cylinder 1.6 is filled with shielding gas and connected to the welding gun through a gas pipe 1.7; a pressure gauge 1.8 is installed on the shielding gas cylinder 1.6. The mechanical arm 1.1 and the control cabinet 5 are connected through a first connection line 7; the welding machine 1.3 and the control cabinet 5 are connected through a second connection line 8.

[0050] The ultrasonic excitation platform includes a support platform 2.1, a substrate workbench 2.2, a first high-energy ultrasonic generator 2.3, a first transducer 2.4 and a first amplitude transformer 2.5; the support platform 2.1 is supported by a leg 2.6; the first high-energy ultrasonic generator 2.3 and the first transducer 2.4 are connected through a third connection line 9, and the first high-energy ultrasonic generator 2.3 and the control cabinet 5 are connected through a fourth connection line 10; the first transducer 2.4 is movably installed on the support platform 2.1; the bottom end of the first amplitude transformer 2.5 is connected to the top end of the first transducer 2.4, and the top end is connected to the substrate workbench 2.2.

[0051] The specific connection method between the first transducer 2.4 and the support platform 2.1 is as follows: an inverted T-shaped slot 2.7 is provided on the support platform 2.1; the ultrasonic excitation platform also includes an inverted T-shaped rod 2.8, a connecting plate 2.9 and a fixing nut 2.10; the bottom end of the inverted T-shaped rod 2.8 is movably inserted into the inverted T-shaped slot 2.7; inverted T-shaped rods 2.8 are symmetrically arranged on both sides of the first transducer 2.4, the connecting plate 2.9 is sleeved on the first transducer 2.4 and the inverted T-shaped rods 2.8 on both sides of the first transducer 2.4, the fixing nut 2.10 is installed on the inverted T-shaped rod 2.8 to press the connecting plate 2.9, the first transducer 2.4 is suspended by the inverted T-shaped rod 2.8, the connecting plate 2.9 and the fixing nut 2.10 to form an ultrasonic excitation unit, and three groups of ultrasonic excitation units are arranged on both sides of the weld 102 of the titanium alloy test plate 101.

[0052] The laser cleaning device 3 and the rotary ultrasonic strengthening device are located above the substrate workbench 2.2 and can move on the surface of the titanium alloy test plate 101.

[0053] The rotary ultrasonic strengthening device comprises a rotary drive mechanism, a second high-energy ultrasonic generator, a second transducer 4.1, a second amplitude rod 4.2, a tool head 4.3 and a ball 4.4; the second high-energy ultrasonic generator is connected to the second transducer 4.1; the second transducer 4.1 is driven to rotate by the rotary drive mechanism; the top end of the second amplitude rod 4.2 is connected to the bottom end of the second transducer 4.1, and the bottom end is connected to the tool head 4.3; the bottom end of the tool head 4.3 is rotatably mounted with a ball 4.4.

[0054] The laser cleaning device 3 and the rotary ultrasonic strengthening device are installed through a clamping frame; the clamping frame includes a clamping beam 6.1, a first vertical beam 6.2, a first horizontal beam 6.3, a second vertical beam 6.4 and a second horizontal beam 6.5; the clamping beam 6.1, the first horizontal beam 6.3 and the second horizontal beam 6.5 are parallel to the substrate workbench 2.2, and the first vertical beam 6.2 and the second vertical beam 6.4 are perpendicular to the substrate workbench 2.2; the first horizontal beam 6.3 is fixed on the first vertical beam 6.2; the clamping beam 6.1 and the first horizontal beam 6.3 are connected through the second vertical beam 6.4; the second horizontal beam 6.5 is fixed on the second vertical beam 6.4. Each beam in the clamping frame can be moved by existing technology to realize the movement of the laser cleaning device 3 and the rotary ultrasonic strengthening device on the surface of the titanium alloy test plate 101.

[0055] The laser cleaning device 3 is fixed on the clamping beam 6.1.

[0056] The rotary ultrasonic strengthening device also includes a shell 4.5 and a bearing 4.6; the shell 4.5 is fixed on the clamping beam 6.1, a support plate 4.7 is arranged inside the shell 4.5, and the bottom end of the shell 4.5 and the support plate 4.7 are both equipped with bearings 4.6; the second transducer 4.1 and the second amplitude transformer 4.2 are rotatably mounted in the shell 4.5 through the bearing 4.6, and the tool head 4.3 extends from the bottom end of the shell 4.5; the rotary drive mechanism includes a motor 4.8, a driving wheel 4.9 mounted on the output shaft of the motor 4.8, a driven wheel 4.10 mounted on the top of the second transducer 4.1, and a synchronous belt 4.11 connecting the driving wheel 4.9 and the driven wheel 4.10; the motor 4.8 is fixed on the second cross beam 6.5 to drive the second transducer 4.1 to rotate.

[0057] The clamping frame drives the laser cleaning device 3 and the rotary ultrasonic strengthening device to move on the surface of the titanium alloy test plate 101 .

[0058] The control cabinet 5 is provided with a power switch 5.1, a power switch indicator light 5.2, a robot arm controller 5.3, a robot arm controller indicator light 5.4, a welding power supply controller 5.5, a welding power supply controller indicator light 5.6, a wire feeding mechanism controller 5.7, a wire feeding mechanism controller indicator light 5.8, an ultrasonic excitation table controller 5.9, an ultrasonic excitation table controller indicator light 5.10, a laser cleaning controller 5.11, a laser cleaning controller indicator light 5.12, an ultrasonic enhancement controller 5.13, an ultrasonic enhancement controller indicator light 5.14, a motor controller 5.15, a motor controller indicator light 5.16, an emergency button 5.17 and an emergency button indicator light 5.18.

[0059] The above-mentioned titanium alloy surface laser ultrasonic composite cleaning and strengthening welding method comprises the following steps.

[0060] S1, Preparation of titanium alloy test plate

[0061] A titanium alloy test plate was prepared by mechanical processing, and a welding groove was processed on the titanium alloy test plate. The blunt edge of the titanium alloy test plate was 1.5 mm, and the single-side groove angle was 30°. After processing, the titanium alloy test plate was placed on the substrate workbench 2.2 to be welded.

[0062] S2, using pulsed laser to clean the front and groove of titanium alloy test plate

[0063] The pulse laser power is 150W, the speed is 6mm / s, the frequency is 23KHz, the pulse width is 500ns, and the scanning spot is rectangular with a size of 100mm×3mm.

[0064] S3, titanium alloy test plate welding

[0065] The welding is performed by using metal arc gas shielded welding, and ultrasonic excitation is applied to the back side of the titanium alloy test plate at the positions on both sides of the weld;

[0066] The diameter of the welding wire is 1.2mm, and 99.99% argon gas is used for protection. The gas flow rate is 25-30L / min, the welding current is 180-240A, the welding speed is 0.3m / min, the arc length correction is 30%, and the welding wire extension length is 15mm.

[0067] The ultrasonic frequency was 20kHz and the ultrasonic power was 4kW;

[0068] After welding is completed, turn off the rotary ultrasonic strengthening device.

[0069] S4, Titanium alloy test plate and surface treatment

[0070] The titanium alloy test plate and the front of the weld were subjected to rotary ultrasonic strengthening treatment, with a rotation speed of 25 r / min, a moving speed of 1 mm / s, a downward force of 0.2 mm, an ultrasonic frequency of 20 kHz, and an ultrasonic power of 4 kW;

[0071] After the treatment is completed, turn off the rotating ultrasonic enhancement device.

[0072] S5, Detection, Analysis, Characterization

[0073] The microstructure, mechanical properties and analysis of the processed titanium alloy test plate surface and weld were analyzed and characterized.

[0074] Conclusion: The test plate and groove surface treated by pulsed laser are clean and tidy, without impurities such as oil, rust and dirt. The high-energy ultrasonic beam generated by the ultrasonic excitation table can refine the grain size of the welded joint, reduce the generation of defects such as pores and inclusions, and improve the mechanical properties of the welded joint. Rotary ultrasonic surface treatment can improve the corrosion resistance and fatigue resistance of the test plate and weld, thereby improving the overall performance of the component product.

[0075] S6, Storage

[0076] The prepared titanium alloy test plates are packed with soft materials and stored in a clean and dry environment. They should be protected from moisture, sunlight, acid, alkali and salt corrosion. The storage temperature is 20°C and the relative humidity is ≤10%.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for laser ultrasonic composite cleaning and strengthening welding of titanium alloy surface, characterized in that: The steps include: S1, Preparation of titanium alloy test plate Processing welding grooves on titanium alloy test plates; S2, using pulsed laser to clean the front and groove of titanium alloy test plate S3, titanium alloy test plate welding The welding is performed by using metal arc gas shielded welding, and ultrasonic excitation is applied to the back side of the titanium alloy test plate at the positions on both sides of the weld; S4, Titanium alloy test plate and surface treatment The titanium alloy test plate and the front side of the weld were subjected to rotary ultrasonic strengthening treatment.

2. The method for laser ultrasonic composite cleaning and strengthening welding of titanium alloy surface according to claim 1, characterized in that: In step S1, the blunt edge of the titanium alloy test plate is 1.5 mm, and the single-side groove angle is 30°; In step S2, the pulse laser power is 150W, the speed is 6mm / s, the frequency is 23KHz, the pulse width is 500ns, and the scanning spot is rectangular with a size of 100mm×3mm; In step S3, the diameter of the welding wire is 1.2 mm, 99.99% argon gas is used for protection, the gas flow rate is 25-30 L / min, the welding current is 180-240 A, the welding speed is 0.3 m / min, the arc length is corrected by 30%, and the welding wire extension length is 15 mm; The ultrasonic frequency was 20kHz and the ultrasonic power was 4kW; In step S4, the rotation speed is 25 r / min, the moving speed is 1 mm / s, the downward force is 0.2 mm, the ultrasonic frequency is 20 kHz, and the ultrasonic power is 4 kW.

3. The method for titanium alloy surface laser ultrasonic composite cleaning and strengthening welding according to claim 2 is characterized in that: Steps S2-S4 are performed using a laser ultrasonic composite cleaning and enhanced welding system; The laser ultrasonic composite cleaning and strengthening welding system includes a welding robot, an ultrasonic excitation table, a laser cleaning device and a rotating ultrasonic strengthening device; The welding robot is used for welding titanium alloy test plates; The ultrasonic excitation platform includes a support platform, a substrate workbench, a first high-energy ultrasonic generator, a first transducer and a first horn; The first high-energy ultrasonic generator is connected to the first transducer; The first transducer is movably mounted on a support platform; The bottom end of the first horn is connected to the top end of the first transducer, and the top end is connected to the substrate workbench; The titanium alloy test plate processed in step S1 is placed on the substrate workbench; The laser cleaning device and the rotary ultrasonic strengthening device are located above the substrate workbench and can move on the surface of the titanium alloy test plate; The rotary ultrasonic strengthening device comprises a rotary drive mechanism, a second high-energy ultrasonic generator, a second transducer, a second horn, a tool head and a ball bearing; The second high energy ultrasonic generator is connected to the second transducer; The second transducer is driven to rotate by a rotation drive mechanism; The top end of the second horn is connected to the bottom end of the second transducer, and the bottom end is connected to the tool head; A ball is rotatably mounted on the bottom end of the tool head.

4. The method for laser ultrasonic composite cleaning and strengthening welding of titanium alloy surface according to claim 3 is characterized in that: The welding robot includes a mechanical arm, a welding gun, a welding machine, welding wire, a wire feeding mechanism and a shielding gas cylinder; The welding gun is installed at the end of the robot arm; The welding machine provides power to the welding gun; The welding wire is loaded into the welding gun through a wire feeding mechanism; The shielding gas cylinder is filled with shielding gas and is connected to the welding gun through a gas pipe; A pressure gauge is installed on the protective gas cylinder.

5. The method for titanium alloy surface laser ultrasonic composite cleaning and strengthening welding according to claim 4, characterized in that: An inverted T-slot is provided on the support platform; The ultrasonic excitation table also includes an inverted T-bar, a connecting plate and a fixing nut; The bottom end of the inverted T-shaped rod is movably inserted into the inverted T-shaped slot; Inverted T-shaped rods are symmetrically arranged on both sides of the first transducer, the connecting plates are sleeved on the first transducer and the inverted T-shaped rods on both sides of the first transducer, the fixing nuts are installed on the inverted T-shaped rods to press the connecting plates, and the first transducer is suspended in the air through the inverted T-shaped rods, the connecting plates and the fixing nuts.

6. The method for laser ultrasonic composite cleaning and strengthening welding of titanium alloy surface according to claim 5, characterized in that: The support table is supported by legs.

7. The method for titanium alloy surface laser ultrasonic composite cleaning and strengthening welding according to claim 6, characterized in that: The laser ultrasonic composite cleaning and enhanced welding system also includes a clamping frame; The rotary ultrasonic strengthening device also includes a housing and a bearing; The housing is fixed on the clamping frame, the second transducer and the second horn are rotatably mounted in the housing through bearings, and the tool head extends from the bottom end of the housing; The rotary drive mechanism includes a motor; The motor is fixed on the clamping frame and drives the second transducer to rotate; The laser cleaning device is fixed on the clamping frame; The clamping frame drives the laser cleaning device and the rotary ultrasonic strengthening device to move on the surface of the titanium alloy test plate.

8. The method for titanium alloy surface laser ultrasonic composite cleaning and strengthening welding according to claim 7, characterized in that: The clamping frame includes a clamping beam, a first vertical beam, a first horizontal beam, a second vertical beam and a second horizontal beam; The clamping beam, the first horizontal beam and the second horizontal beam are parallel to the substrate workbench, and the first vertical beam and the second vertical beam are perpendicular to the substrate workbench; The first cross beam is fixed on the first vertical beam; The clamping beam and the first horizontal beam are connected by a second vertical beam; The second cross beam is fixed on the second vertical beam; The laser cleaning device and the housing are fixed to the clamping beam; The motor is fixed on the second crossbeam; The rotary drive mechanism also includes a driving wheel installed on the output shaft of the motor, a driven wheel installed on the top of the second transducer, and a synchronous belt connecting the driving wheel and the driven wheel.

9. The method for titanium alloy surface laser ultrasonic composite cleaning and strengthening welding according to claim 8, characterized in that: The laser ultrasonic composite cleaning and enhanced welding system also includes a control cabinet; The control cabinet is provided with a power switch, a power switch indicator light, a robotic arm controller, a robotic arm controller indicator light, a welding power supply controller, a welding power supply controller indicator light, a wire feeding mechanism controller, a wire feeding mechanism controller indicator light, an ultrasonic vibration table controller, an ultrasonic vibration table controller indicator light, a laser cleaning controller, a laser cleaning controller indicator light, an ultrasonic enhancement controller, an ultrasonic enhancement controller indicator light, a motor controller, a motor controller indicator light, an emergency button and an emergency button indicator light; The robot arm and the control cabinet are connected via a first connection line; The welding machine and the control cabinet are connected via a second connection line; The first high-energy ultrasonic generator and the first transducer are connected via a third connection line, and the first high-energy ultrasonic generator and the control cabinet are connected via a fourth connection line.

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