CN109079323B - Platform and method for strengthening aluminum alloy by non-penetration laser welding - Google Patents

Abstract

The invention discloses a platform and a method for strengthening aluminum alloy non-penetration laser welding, wherein a first mechanical arm and a second mechanical arm are respectively provided with a first laser head and a second laser head, a processing chamber is respectively connected with a water inlet pipe and a water outlet pipe, and a butt welding plate is clamped and positioned by a clamp in the processing chamber; the water inlet pipe is connected with a water pump; the amplitude transformer is fixed on the inner wall of the treatment chamber, and the working head of the amplitude transformer is positioned below a preset upper limit water level; a blind road is arranged in the center of the butt joint end surface of the welding plate before welding, so that the downward flowing speed of the metal solution on the front wall of the key hole during welding is effectively reduced, and the back of the welding plate is prevented from being burnt through or full penetration welding is formed; after welding, laser impact treatment is carried out, so that surface grains of the aluminum alloy laser welding joint can be effectively refined, and the mechanical property of the joint is improved. In addition, the laser welding and laser impact technology is fused into one platform, laser impact treatment is carried out after welding operation, secondary positioning and clamping of workpieces are avoided, and production efficiency and automation level are improved.

Description

Platform and method for strengthening aluminum alloy by non-penetration laser welding

Technical Field

The invention relates to the technical field of welding, in particular to a platform and a method for strengthening aluminum alloy non-penetration laser welding.

Background

The laser welding technology is widely applied to the industries of rail vehicle manufacturing, aerospace part manufacturing and the like due to the advantages of high power density, small heat affected zone, high depth-to-width ratio of welding seams and the like. The railway vehicles in China are in front of the world and become a main export product in China, and the railway transportation in China is still constantly combined with the requirements of users, so that the raw materials and the manufacturing process are strictly controlled. In order to continuously accelerate a high-speed train, an effective approach is light weight. The aluminum alloy section bar is widely applied to the railway vehicle manufacturing and other numerous fields in such a way that the aluminum alloy section bar has small density, good corrosion resistance, compact and firm oxide film protection on the surface and good extrusion performance.

Welding of aluminum alloy materials is an important technique in railway car manufacturing and other fields. In order to ensure the working environment of components in the box body, the reinforcing ribs outside the box body are generally subjected to non-penetration welding, and in addition, in the manufacture of the car shell, in order to ensure the attractive appearance, the shell plates are required to be subjected to non-penetration welding. Compared with full penetration laser welding, aluminum alloy non-penetration laser welding is more sensitive to welding parameter changes, and the defects of uncombined joints, back burning-through and the like are easily caused by fine changes of process parameters.

The search finds that the welding plate is placed on a workbench with cooling water according to the patent 'a laser non-penetration welding device' (application number: 201520134200.6), so that the problem of thermal deformation of a lower plate in non-penetration welding can be effectively solved, but the device has no effect on oxidative discoloration of the back surface of the lower plate. The method for welding by the non-penetration laser welding equipment (application number: 201410242022.9) can be used for capturing back temperature in real time by arranging an infrared temperature sensing system on the back of a welding line, and can be adjusted in real time, but the difficulty of arranging a follow-up device on a sensor on the back of a welding plate in an industrial field is increased, and the process and the device are complex.

The laser shock treatment is a surface modification strengthening technology, and utilizes an absorption layer covered on the surface of a metal material to absorb high-amplitude laser energy to directly gasify to form a strong-field shock compression wave, and acts on the surface of the metal material, so that metal surface crystal grains can be thinned or nanocrystallized, and surface crystal grains can be compressed, domestic scholars Luo Xinmin and the like in journal paper (Chinese laser, 2009,36 (12): 3323-3328) and Zhang Qinglai and the like in journal paper (Chinese laser, 2014,41 (4): 0403010) show that laser shock is beneficial to improving metal fatigue strength, and experiments in journal paper (Chinese laser, 2013,40 (5): 0503005) show that laser shock energy enables fatigue performance of a steel welding joint to be obviously improved.

Disclosure of Invention

The invention aims to provide a platform and a method for strengthening aluminum alloy non-penetration laser welding so as to form a non-penetration joint with good aluminum alloy forming, refine surface grains of the aluminum alloy laser welding joint, improve mechanical property, hardness and corrosion resistance of the joint, and integrate laser welding and laser impact technology into one platform, thereby avoiding secondary positioning and clamping of workpieces and improving production efficiency.

The invention adopts the technical scheme that: a platform and a method for strengthening aluminum alloy non-penetration laser welding comprise a first mechanical arm, a second mechanical arm, a substrate, a processing chamber module, an ultrasonic generating module, a second laser head, a first laser head, a control module, a first laser and a second laser; the substrate is provided with a first mechanical arm, a second mechanical arm, a treatment chamber module and an ultrasonic generation module; a first laser head and a protective gas nozzle are carried on the first mechanical arm, a second laser head is carried on the second mechanical arm, the first laser head is connected with the first laser through an optical fiber, and the second laser head is connected with the second laser through an optical fiber; the inner wall of the treatment chamber is also provided with a water level sensor, an upper limit water level and a lower limit water level are preset, and the working head of the amplitude transformer is positioned below the preset upper limit water level.

The treatment chamber module comprises a treatment chamber, a water inlet pipe, a water outlet pipe, a water pump, a welding plate and a clamp; the concrete structure is as follows: the treatment chamber is provided with a water inlet and a water outlet, the water inlet pipe and the water outlet pipe are respectively connected, the water inlet pipe is connected with a water pump, and the butt welding plate is clamped and positioned by a clamp positioned in the treatment chamber.

The control module comprises a controller, a first laser, a second laser, a first mechanical arm, a second mechanical arm, a cold water system, a protective gas system, a water pump and an ultrasonic transmitter; the specific connection is as follows: the controller is respectively connected with the first laser, the second laser, the first mechanical arm, the second mechanical arm, the cold water system, the shielding gas system, the water pump and the ultrasonic transmitter.

The ultrasonic generating module comprises an amplitude transformer and an ultrasonic generator; the concrete connection is that the amplitude transformer is connected with the ultrasonic generator and is fixed on the inner wall of the treatment chamber.

Before welding, a blind road is arranged at the center of the butt joint gap end face of the welding plate.

The first laser adopts Nd: YAG solid laser and CO ₂ Any one of a laser, a disk laser, or a semiconductor laser; the second laser adopts Nd: YAG solid laser.

The working steps of the platform are as follows:

1. and (3) after acetone cleaning is carried out on the aluminum alloy plate before welding, clamping the welded plate on a clamp in the processing chamber.

2. The first mechanical arm enables the first laser head to reach the working area, the first laser emits light, and the welding plate is subjected to non-penetration welding in the atmosphere of protective gas under the driving of the first mechanical arm. And resetting the first mechanical arm to a non-working area after welding is finished.

3. After the weld joint is cooled, the water inlet pipe is filled with water, and after the water surface reaches a preset upper limit water level, the ultrasonic generator works, and ultrasonic cleaning is carried out on the welding plate and the treatment chamber. After the cleaning is finished, the ultrasonic generator stops working.

4. And (3) discharging water from the water outlet pipe, and manually sticking a layer of black adhesive tape to the area near the welding seam on the upper surface of the welding plate when the water level in the chamber to be treated is lower than that of the welding plate.

5. After the water surface reaches the lower limit water level, the water inlet pipe is used for water inflow for the second time, after the water surface reaches the preset upper limit water level, the second mechanical arm enables the second laser head to reach the working area, the second laser emits light, and laser impact treatment is carried out on the welding seam under the driving of the second mechanical arm. And resetting the second mechanical arm to a non-working area after the laser shock treatment is finished.

6. And (5) discharging water from the water outlet pipe, and manually taking down the welded plate.

In general, the invention has the following beneficial effects:

1. according to the invention, the blind channel is arranged at the center of the butt joint end surfaces of the welding plates before welding, so that the downward flow speed of the metal solution on the front wall of the key hole during welding can be effectively reduced, and the back of the welding plates is prevented from being burnt or full penetration welding is formed.

2. The method for forming the blind sidewalk can reduce the volume of metal to be melted during butt joint, greatly reduce the required laser power and save the cost.

3. According to the invention, laser impact treatment is carried out after welding, so that surface grains of the aluminum alloy laser welding joint can be effectively refined, and the mechanical property, hardness and corrosion resistance of the joint are improved.

4. According to the invention, the laser welding and laser impact technology is integrated into one platform, and laser impact treatment is performed after welding operation, so that the secondary positioning and clamping of workpieces are avoided, and the production efficiency and the automation level are greatly improved.

Drawings

FIG. 1 is an apparatus diagram of a laser welding step of the present invention;

FIG. 2 is a diagram of an apparatus for laser shock processing according to the present invention;

FIG. 3 is a block diagram of a control system of the present invention;

FIG. 4 is an isometric view of a weld plate with blind sidewalk according to the present invention;

FIG. 5 is a cross-sectional view of a solder plate with blind vias according to the present invention;

fig. 6 is a schematic diagram of the blind via-opening welding plate according to the present invention.

Description of the reference numerals: 1. the device comprises a first mechanical arm, a second mechanical arm, a substrate, a processing chamber, a fixture, a water inlet pipe, a water outlet pipe, a welding plate and a water inlet pipe, wherein the first mechanical arm, the second mechanical arm, the substrate, the processing chamber, the fixture, the water inlet pipe, the water outlet pipe and the welding plate are arranged in sequence, and the welding plate is arranged in sequence horn, 10, ultrasonic generator, 11, second laser head, 12, first laser head, 13, controller, 14, first laser the laser system comprises a first laser, a second laser, a cold water system, a protective gas system, a water pump, a keyhole front wall metal solution, a protective gas nozzle, a laser beam, a blind road, a butt gap, a molten pool, a solidification area, a keyhole and a blind road.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

As shown in fig. 1, 2 and 3, the device comprises a first mechanical arm (1), a second mechanical arm (2), a substrate (3), a processing chamber module, an ultrasonic generation module, a second laser head (11), a first laser head (12), a control module, a first laser (14) and a second laser (15); the substrate (3) is provided with a first mechanical arm (1), a second mechanical arm (2), a treatment chamber module and an ultrasonic generation module; a first laser head (12) and a protective gas nozzle (20) are mounted on the first mechanical arm (1), a second laser head (11) is mounted on the second mechanical arm (2), the first laser head (12) is connected with the first laser (14) through an optical fiber, and the second laser head (11) is connected with the second laser (15) through an optical fiber; the inner wall of the treatment chamber (4) is also provided with a water level sensor, an upper limit water level and a lower limit water level are preset, and the water level sensor senses the real-time water surface; the working head of the amplitude transformer (9) is positioned below a preset upper limit water level; the amplitude transformer (9) is used for carrying out ultrasonic cleaning in the welded welding plate (8) and the treatment chamber (4), so as to remove dust and partial impurities on the surface of the welding seam generated in the welding process.

The treatment chamber module comprises a treatment chamber (4), a water inlet pipe (6), a water outlet pipe (7), a water pump (18), a welding plate (8) and a clamp (5); the concrete structure is as follows: the treatment chamber (4) is provided with a water inlet and a water outlet, the treatment chamber is respectively connected with a water inlet pipe (6) and a water outlet pipe (7), the water inlet pipe (6) is connected with a water pump (18), the treatment chamber (4) can be supplied with water, and the butt welding plate (8) is clamped and positioned by the clamp (5) positioned in the treatment chamber (4).

The control module comprises a controller (13), a first laser (14), a second laser (15), a first mechanical arm (1), a second mechanical arm (2), a cold water system (16), a shielding gas system (17), a water pump (18) and an ultrasonic emitter (10); the specific connection is as follows: the controller (13) is respectively with first laser instrument (14), second laser instrument (15), first arm (1), second arm (2), cold water system (16), protection gas system (17), water pump (18), ultrasonic transmitter (10), and controller (13) is respectively to the work start-stop control of first laser instrument (14), second laser instrument (15), first arm (1), second arm (2), cold water system (16), protection gas system (17), water pump (18), ultrasonic transmitter (10), can be industrial computer, PLC etc..

The ultrasonic generation module comprises an amplitude transformer (9) and an ultrasonic generator (10); the concrete connection is that the amplitude transformer (9) is connected with the ultrasonic generator (10), and the amplitude transformer (9) is fixed on the inner wall of the treatment chamber (4).

The first laser adopts Nd: YAG solid laser and CO ₂ Any one of a laser, a disk laser, or a semiconductor laserSeed; the second laser adopts Nd: YAG solid laser.

The working steps of the platform are as follows:

1. and (3) after acetone cleaning is carried out on the aluminum alloy welding plate (8) before welding, the welding plate (8) is clamped on a clamp (5) in the processing chamber (4).

2. The first mechanical arm (1) enables the first laser head (12) to reach a working area, the first laser (14) emits light, the welding plate (8) is subjected to non-penetration welding under the driving of the first mechanical arm (1), and meanwhile the protective gas nozzle (20) applies argon protection. And resetting the first mechanical arm (1) to a non-working area after welding is finished.

3. After the welding line is cooled, the water inlet pipe (6) is filled with water, and after the water surface reaches a preset upper limit water level, the ultrasonic generator (10) works, and ultrasonic cleaning is carried out on the welding plate (8) and the inside of the treatment chamber (4). After the cleaning is finished, the ultrasonic generator (10) stops working.

4. And (3) discharging water from the water outlet pipe (7), and manually sticking a layer of black adhesive tape to the area near the welding seam on the upper surface of the welding plate (8) when the water level in the treatment chamber (4) is lower than that of the welding plate (8).

5. After the water surface reaches the lower limit water level, the water inlet pipe (6) is used for water inflow for the second time, after the water surface reaches the preset upper limit water level, the second mechanical arm (2) enables the second laser head (11) to reach the working area, the second laser (15) emits light, and laser impact treatment is carried out on the welding seam area under the driving of the second mechanical arm (2). And resetting the second mechanical arm (2) to a non-working area after the laser shock treatment is finished.

6. And the water outlet pipe (7) is used for discharging water, and the welding plate (8) is manually taken down.

According to researches, one important reason for causing the burn-through or full penetration phenomenon of the back of the welding plate in the non-penetration welding is that the lower half part of the welding plate becomes a weak zone and is easy to break down due to the impact action of the metal liquid flowing downwards at a high speed by the front wall of the key hole during welding, and the metal liquid part of the front wall of the key hole can be led into the blind road by the method of opening the blind road at the end surface, so that the downward flowing speed of the metal solution of the front wall of the key hole during welding is effectively reduced, and the back of the welding plate is prevented from being burnt through or forming full penetration welding.

As shown in fig. 4, 5 and 6, before welding, a blind passage (22) is formed in the center of the end face of the butt joint gap (23) of the welding plate (8), so that the metal liquid (19) on the front wall of the key hole can be partially drained into the blind passage (22) to form a metal solution (27) in the blind passage, the downward flowing speed of the metal solution (19) on the front wall of the key hole during welding is effectively reduced, and the back of the welding plate is prevented from being burnt or the full penetration welding is formed.

While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the invention, such changes and modifications are also intended to be within the scope of the invention.

Claims (2)

1. A laser welding strengthening method of an aluminum alloy non-penetration laser welding strengthening platform is characterized by comprising the following steps of: the method comprises the following steps:

firstly, acetone cleaning is carried out on an aluminum alloy plate before welding, and then the aluminum alloy plate is used as a welding plate (8) to be clamped on a clamp (5) in a treatment chamber (4);

secondly, enabling a first laser head (12) to reach a working area by a first mechanical arm (1), enabling a first laser (14) to emit light, performing non-penetration welding on a welding plate (8) in a protective gas atmosphere under the driving of the first mechanical arm (1), and resetting the first mechanical arm (1) to the non-working area after the welding is finished;

thirdly, after the welding line is cooled, water is fed into the water inlet pipe (6), after the water surface reaches a preset upper limit water level, the ultrasonic generator (10) works, ultrasonic cleaning is carried out on the welding plate (8) and the inside of the processing chamber (4), and after the cleaning is finished, the ultrasonic generator (10) stops working;

fourthly, the water outlet pipe (7) is used for discharging water, and when the water level in the treatment chamber (4) is lower than that of the welding plate (8), a layer of black adhesive tape is manually stuck to the area near the welding seam on the upper surface of the welding plate (8);

fifthly, after the water surface reaches the lower limit water level, the water inlet pipe (6) is fed for the second time, after the water surface reaches the preset upper limit water level, the second mechanical arm (2) enables the second laser head (11) to reach the working area, the second laser (15) emits light, laser impact treatment is carried out on the welded joint under the driving of the second mechanical arm (2), and after the laser impact treatment is finished, the second mechanical arm is reset to the non-working area;

sixthly, discharging water from the water outlet pipe (7), and manually taking down the welded plate (8);

before welding, a blind channel (22) is arranged at the center of the butt joint gap end face of the welding plate (8);

the aluminum alloy non-penetration laser welding reinforced platform comprises a first mechanical arm (1), a second mechanical arm (2), a substrate (3), a processing chamber module, an ultrasonic generation module, a second laser head (11), a first laser head (12), a control module, a first laser (14) and a second laser (15); the substrate (3) is provided with a first mechanical arm (1), a second mechanical arm (2), a treatment chamber module and an ultrasonic generation module; a first laser head (12) and a protective gas nozzle (20) are mounted on the first mechanical arm (1), a second laser head (11) is mounted on the second mechanical arm (2), the first laser head (12) is connected with the first laser (14) through an optical fiber, and the second laser head (11) is connected with the second laser (15) through an optical fiber; the inner wall of the treatment chamber (4) is also provided with a water level sensor, an upper limit water level and a lower limit water level are preset, and the working head of the amplitude transformer (9) is positioned below the preset upper limit water level;

the treatment chamber module comprises a treatment chamber (4), a water inlet pipe (6), a water outlet pipe (7), a water pump (18) and a clamp (5); the concrete structure is as follows: the treatment chamber (4) is provided with a water inlet and a water outlet, which are respectively connected with a water inlet pipe (6) and a water outlet pipe (7), the water inlet pipe (6) is connected with a water pump (18), and the butt welding plate (8) is clamped and positioned by a clamp (5) positioned in the treatment chamber (4);

the ultrasonic generation module comprises an amplitude transformer (9) and an ultrasonic generator (10); the concrete connection is that the amplitude transformer (9) is connected with the ultrasonic generator (10), and the amplitude transformer (9) is fixed on the inner wall of the treatment chamber (4).

2. The laser welding strengthening method according to claim 1, wherein: the first laser (14) adopts Nd: YAG solid laser and CO ₂ Any one of a laser, a disk laser, or a semiconductor laser; the second laser (15) employs Nd: YAG solid laser.