Light-wire-powder coaxial variable-frequency adjustable tissue programming laser welding method and device

Abstract

The invention belongs to the technical field of welding manufacturing, and discloses a light-wire-powder coaxial variable-frequency adjustable tissue programming laser welding method and device. The device mainly comprises a laser welding system, a light-wire-powder coaxial feeding mechanism, a molten pool real-time temperature monitoring device and a self-adaptive frequency conversion regulator, according to the method, the light-wire-powder coaxial feeding mechanism is adopted to achieve stable and synchronous feeding of wire welding materials and powder welding materials, and the self-adaptive frequency conversion regulator is adopted based on a laser vision sensing device. The temperature distribution characteristics of a molten pool and a solidified welding seam are monitored in real time, the microstructure form is deduced, frequency conversion sub-control adjustment wire feeding, powder feeding and laser energy waveforms are fed back, and finally welding seam structure customized programming control welding is achieved. The light-wire-powder coaxial variable-frequency adjustable structure programming laser welding method is high in filling efficiency, high in adjusting capacity and controllable in welding seam microcell structure, and the problems that defects occur frequently and the structure and performance are not uniform in the welding process of a complex structure are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of welding manufacturing, and discloses a "light-silk-powder" coaxial variable frequency adjustable organization programming laser welding method and device. Background Art

[0002] The laser beam welding technology for complex main load-bearing components in aviation currently has common difficulties: the plate thickness is large, and it is difficult to avoid the problems of coarse organization, non-uniform organization growth, and uneven performance in local areas of complex components during welding. Some lightweight metal materials have coarse columnar crystals and longitudinal growth of cross-layer fusion lines after multiple passes of welding. This organizational feature will seriously reduce the plasticity index of large-sized components, thereby affecting the service performance of the main load-bearing parts under actual flight conditions. In order to solve the problems of frequent defects and uneven organization and performance in the welding process of complex structures, the existing solutions are often ultrasonic-assisted, magnetic-field-assisted and other external energy field-assisted methods to refine the grains and regulate the organization to improve the performance. The regulation effect is limited compared to the in-situ grain refinement regulation effect of the particles in the dynamic welding process, and the production efficiency is low. Therefore, how to develop an efficient welding method with adjustable dynamic organization for the welding process has become an urgent need. Summary of the invention

[0003] The purpose of the present invention is to provide a "light-silk-powder" coaxial variable frequency adjustable organizational programming laser welding method and device, through the method of "real-time monitoring of weld temperature state → determination of organizational morphology → determination by adaptive variable frequency regulator efficient algorithm → variable frequency regulation of laser energy and silk-powder filling parameters", to achieve in-situ adaptive programming and controllable weld organization, and solve the problems of frequent defects, uneven organization and performance in the welding process of complex structures.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] A "light-silk-powder" coaxial variable frequency adjustable tissue programming laser welding method mainly includes the following steps:

[0006] Step 1: Turn on the shielding gas system to ensure that the workpiece to be welded and the filler welding materials in the shielding cabin are continuously in a high-purity inert atmosphere during the welding process;

[0007] Step 2: Turn on the laser welding system and feeding mechanism in sequence, control the movement of the six-axis robot, teach the welding process, and preset key welding process parameters: laser power P, pulse frequency H, welding speed V w , wire feeding speed V f , powder feeding speed V p ;

[0008] Step 3: Turn on the molten pool real-time temperature detection device and the adaptive frequency conversion regulator. During the welding process, the molten pool monitors the temperature change of the weld area in real time and transmits the temperature data to the computer workstation. The database analyzes and determines the current organizational morphology and transmits the information to the adaptive frequency conversion regulator.

[0009] Step 4: The adaptive frequency conversion regulator can make efficient algorithm judgments based on the real-time changes of organizational characteristic information. It has the functions of variable frequency adjustment and peak value adjustment of laser energy and silk-powder filling parameters. The regulator is equipped with a judgment formula for the matching mechanism between parameters to ensure dynamic matching during the multi-factor adjustment process, and realize dynamic regulation of the fine grain content in the molten pool according to the changes in organizational morphology.

[0010] Step 5: After welding is completed, the protective chamber is ventilated for 5-10 seconds. After the workpiece cools to room temperature, the welding system, feeding mechanism, temperature monitoring device, frequency converter and protective gas system are turned off in sequence, finally realizing adaptive silk-powder synchronous laser welding of thick plate structure and solving the problem of uneven structure and performance of complex thick plate.

[0011] Optionally, the laser head lateral temperature monitoring device records the temperature change of the molten pool in real time, transmits the temperature to the computer, and records the high temperature residence time ΔT above the phase transition temperature of the interlayer weld and the molten pool cooling rate R c , and compare it with the metal material solidification database to determine the organizational morphology, and the current grain size G s Compared with the fine grain size G of the material in the database a The difference ΔG = G s -G a Transmitted to the adaptive frequency converter.

[0012] Optionally, the adaptive frequency conversion regulator takes grain refinement as the main control strategy, and during the welding process, based on the real-time transmitted temperature information and organizational morphology judgment information, adaptively controls the filling parameters, wire feeding parameters and laser energy of the fine-grained powder to achieve dynamic programming of the interlayer organizational morphology.

[0013] Optionally, the specific parameter control strategy of the adaptive variable frequency regulator is that when the regulator receives the ΔG signal, the powder feeding speed V p1 =V p0 +K a ×(G s -G a ), wire feeding speed V f1 =V f0 -K b ×(G s -G a ), laser power P = η p ×V p1 +η f ×V f1 .

[0014] Optionally, when performing wire-powder synchronous laser welding on different metal materials, the powder feeding control coefficient K a , Wire feeding control coefficient K b , Solder powder unit melting heat coefficient ηp and the unit melting heat coefficient of welding wire ηf Will change, carry out process tests based on the material's unique welding characteristics, and fit the revised coefficients.

[0015] A "light-silk-powder" coaxial variable frequency adjustable organization programming laser welding device, mainly comprising a laser welding system, a "light-silk-powder" coaxial feeding mechanism, a molten pool real-time temperature monitoring device and an adaptive variable frequency regulator;

[0016] The laser welding system generates a high-energy beam light source from a laser generator and transmits it through an optical fiber. The laser light path is a hollow optical system, which passes through a collimator, a ridge beam splitter, and a hollow reflector in sequence to achieve a 90° bend in the light path and a hollow diameter of 50-100 mm. The annular laser beam acts on the surface of the workpiece to be welded in the inert gas protection cabin;

[0017] The "light-wire-powder" coaxial feeding mechanism mainly includes a powder feeder, a powder storage tank, a powder feeding conduit, a wire feeder and a laser head connected to the powder feeding tube, and a specific circular hole structure in the center of the hollow reflector. The filler wire to be welded is fed from the central area to achieve a coaxial fuse effect; the filling powder is composed of fine-grained strengthening particles, which are connected to the powder feeding port on the laser head by the powder feeder to transport the powder to the center of the weld coaxially with the laser beam and the welding wire;

[0018] The real-time temperature monitoring device is fixed to the front side of the laser head in the welding direction, performs infrared laser scanning on the weld area, monitors the temperature data in real time, and transmits key information to the computer for analysis and extraction;

[0019] The adaptive frequency conversion regulator has three adjustment functions: laser energy, wire feeding parameters, and powder feeding parameters. It can adaptively adjust key parameters such as energy size, pulse waveform, and wire feeding-powder feeding filling ratio based on the judgment algorithm.

[0020] The beneficial effects of the present invention are as follows:

[0021] The present invention provides a "light-silk-powder" coaxial variable frequency adjustable organization programming laser welding method and device, which monitors the temperature state of the weld in real time through a laser sensor, and adaptively adjusts the laser energy and silk-powder filling parameters of the welding process through computer database judgment and regulator high-efficiency algorithm decision-making, realizes in-situ adaptive programming control of the weld organization, and solves the problems of frequent defects and uneven organization and performance in the welding process of complex structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the internal planing structure, temperature monitoring device and adaptive frequency conversion regulator device of the integrated "light-silk-powder" coaxial welding laser head;

[0023] Figure 2 It is a structural schematic diagram of the "light-silk-powder" coaxial frequency-adjustable organization programming laser welding device provided by the present invention;

[0024] In the figure: 1. Ar gas protection gas; 2. Inert gas protection chamber; 3. Laser generator; 4. Laser head; 5. Wire feeder; 6. Powder feeder; 7. Six-axis robot; 8. Real-time temperature monitoring device; 9. Computer; 10. Adaptive frequency converter; 11. Workpiece to be welded;

[0025] 41. Optical fiber; 42. Collimator; 43. Roof beam splitter; 44. Hollow reflector; 45. Ring laser beam; 46. Powder delivery port;

[0026] 51. Filler wire;

[0027] 61. Powder storage box. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0029] Obviously, the described embodiments are only some embodiments of the present invention, not all 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.

[0030] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0032] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0033] The present invention discloses a "light-silk-powder" coaxial variable frequency adjustable organization programming laser welding device, such as Figure 1 The invention mainly includes a laser welding system, a "light-silk-powder" coaxial feeding mechanism, a real-time temperature monitoring device for the molten pool and an adaptive frequency conversion regulator. The invention is further described below through a specific embodiment.

[0034] This example is to achieve butt welding of 20mm TC4 titanium alloy thick plate through the above-mentioned "light-silk-powder" coaxial variable frequency adjustable organization programming laser welding device. The implementation process is as follows:

[0035] Step 1: Clean the welding groove before welding, place the plate to be welded in the protection chamber, turn on the protection gas system, and ensure that the workpiece to be welded and the filling welding material in the protection chamber are continuously in a high-purity inert atmosphere during the welding process;

[0036] Step 2: Turn on the laser welding system and feeding mechanism in turn, control the movement of the six-axis robot, teach the welding process, and preset key welding process parameters: laser power P = 3.5kW, pulse frequency H = = 30Hz, welding speed V w =0.8m / min, wire feeding speed V f =1.2m / min, powder feeding speed V p =1.5rpm / s;

[0037] Step 3: Turn on the real-time temperature detection device of the molten pool and the adaptive frequency conversion regulator. During the welding process, the temperature detection device performs infrared laser scanning on the weld area, monitors the temperature data in real time, and transmits the temperature curve data to the computer workstation to analyze the α and β phase transition temperature residence time and cooling rate, and compare the TC4 organizational transformation temperature curve database to determine that the current organizational morphology is columnar crystal, and set ΔG = 18 μm (G s )-2μm(G a ) information is transmitted to the adaptive frequency conversion regulator;

[0038] Step 4: The adaptive frequency conversion regulator can make efficient algorithm judgment based on the real-time changes of the α and β phase columnar crystal size and grain size organizational characteristic information: V p1 =1.5rpm / s+K a ×(18μm-2μm)=1.82rpm / s, wire feeding speed V fl =1.2m / min-K b ×(18μm-2μm)=1.04m / min, laser power P=η p ×1.82+η f ×1.04=3.74kW, where for TC4 material, Ka=0.02, K b =0.01,η p =1.2,η f =1.5. The filling amount of fine grains is regulated according to the organizational morphology, and the in-situ adaptive programming control of the TC4 thick plate weld organization is achieved;

[0039] Step 5: After welding is completed, the protective chamber is ventilated for 10 seconds. After the TC4 thick plate workpiece cools to room temperature, the welding system, feeding mechanism, temperature monitoring device, frequency converter and protective gas system are turned off in sequence, and finally adaptive silk-powder synchronous laser welding of thick plate structure is realized to solve the problem of uneven structure and performance of complex thick plate.

[0040] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

[0041] The present invention is not limited in any way to the exemplary embodiments presented in the specification and drawings. Portions of the embodiments shown and described are expressly understood to be incorporated into this specification and to fall within the scope of the present invention. Moreover, many variations are possible within the scope of the present invention as outlined in the claims. Furthermore, any reference signs in the claims should not be construed as limiting the scope of the present invention.

Claims

1. A "light-silk-powder" coaxial variable frequency adjustable tissue programming laser welding method, mainly comprising the following steps: Step 1: start the protective gas system to ensure that the workpiece (11) to be welded and the filler welding material in the protective chamber (2) are continuously in a high-purity inert atmosphere during the welding process; Step 2: Turn on the laser welding system (3) and the feeding mechanism in turn, control the movement of the six-axis robot (7), teach the welding process, and preset key welding process parameters: laser power P, pulse frequency H, welding speed V w , wire feeding speed V f , powder feeding speed V p ; Step 3, turning on the molten pool real-time temperature detection device (8) and the adaptive variable frequency regulator (10), during the welding process, the molten pool monitors the temperature change of the weld area in real time, and transmits the temperature data to the computer workstation (9), and the database analyzes and determines the current organizational morphology and transmits the information to the adaptive variable frequency regulator (10); Step 4: The adaptive frequency conversion regulator (10) can perform efficient algorithm judgment based on the real-time changes of the organizational characteristic information, and has the functions of variable frequency adjustment and peak value adjustment of laser energy and silk-powder filling parameters. The regulator is provided with a parameter matching mechanism judgment formula to ensure dynamic matching in the multi-factor adjustment process, and realize dynamic regulation of the fine grain content in the molten pool according to the organizational morphology changes; Step 5: After welding is completed, ventilation is continued in the protective chamber (2) for 5-10 seconds. After the workpiece (11) cools to room temperature, the welding system (3), the feeding mechanism, the temperature monitoring device (8), the frequency converter (10) and the protective gas (1) system are sequentially closed, thereby finally achieving adaptive silk-powder synchronous laser welding of thick plate structures and solving the problem of uneven structure and performance of complex thick plates.

2. The "light-silk-powder" coaxial variable frequency adjustable tissue programming laser welding method as claimed in claim 1 is characterized in that: The lateral temperature monitoring device (8) of the laser head (4) records the temperature change of the molten pool in real time, transmits the temperature to the computer (9), records the high temperature residence time ΔT above the phase change temperature of the interlayer weld and the molten pool cooling rate Rc, compares them with the metal material solidification database to determine the organizational morphology, and calculates the current grain size G s Compared with the fine grain size G of the material in the database a The difference ΔG = G s -G a Transmitted to the adaptive variable frequency regulator (10).

3. The "light-silk-powder" coaxial variable frequency adjustable tissue programming laser welding method as claimed in claim 2 is characterized by: The adaptive variable frequency regulator (10) takes grain refinement as the main control strategy, and adaptively controls the filling parameters, wire feeding parameters and laser energy of the fine-grained powder based on the real-time transmitted temperature information and organizational morphology judgment information during the welding process, thereby realizing dynamic programming of the interlayer organizational morphology.

4. The "light-silk-powder" coaxial variable frequency adjustable tissue programming laser welding method as claimed in claim 3 is characterized by: The specific parameter control strategy of the adaptive variable frequency regulator (10) is that when the regulator receives the ΔG signal, the powder feeding speed V p1 =V p0 +K a ×(G s -G a ), wire feeding speed V f1 =V f0 -K b ×(G s -G a ), laser power P = η p ×V p1 +η f ×V f1 .

5. The "light-silk-powder" coaxial variable frequency adjustable tissue programming laser welding method as claimed in claim 4 is characterized in that: When performing wire-powder synchronous laser welding on different metal materials, the powder feeding control coefficient K a , wire feeding control coefficient K b , Solder powder unit melting heat coefficient η p and the unit melting heat coefficient of welding wire η f Will change, carry out process tests based on the material's unique welding characteristics, and fit the revised coefficients.

6. The "light-silk-powder" coaxial variable frequency adjustable organization programming laser welding device as claimed in claim 1 mainly comprises a laser welding system, a "light-silk-powder" coaxial feeding mechanism, a molten pool real-time temperature monitoring device (8) and an adaptive variable frequency regulator (10); The laser welding system generates a high-energy beam light source by a laser generator (3), which is transmitted through an optical fiber (41). The laser light path is a hollow optical system, which passes through a collimator (42), a ridge beam splitter (43), and a hollow reflector (44) in sequence, so that the light path is bent by 90 degrees and the hollow diameter is 50-100 mm. The annular laser beam (45) acts on the surface of the workpiece to be welded in the inert gas protection cabin (2); The "light-wire-powder" coaxial feeding mechanism mainly comprises a powder feeder (6), a powder storage tank (61), a powder feeding conduit port (46), a wire feeder (5) and a laser head (4) connected to the powder feeding tube, a central specific circular hole structure of the hollow reflector (44), and the welding wire (51) to be welded is fed from the central area to achieve a coaxial fuse effect; the filling powder component is fine-grained strengthening particles, and is connected to the powder feeding port (46) on the laser head (4) by the powder feeder (6), and the powder is transported to the center of the weld coaxially with the laser beam (45) and the welding wire (51); The real-time temperature monitoring device (8) is fixed to the front side of the laser head in the welding direction, performs infrared laser scanning on the weld area, monitors temperature data in real time, and transmits key information to the computer (9) for analysis and extraction; The adaptive frequency conversion regulator (10) has three adjustment functions: laser energy, wire feeding parameters, and powder feeding parameters, and can adaptively adjust key parameters such as energy size, pulse waveform, and wire feeding-powder feeding filling ratio based on a determination algorithm.

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