A coaxial laser wire feeding cladding system and process

Abstract

The application provides a laser coaxial wire feeding welding system and process, which comprises a control system, a wire feeder mechanism, a motion execution mechanism and a laser mechanism, the wire feeder mechanism comprises a push-pull wire feeder and a push-pull wire feeding device, the control system is connected with the push-pull wire feeder through a wire feeder control circuit, the push-pull wire feeder is connected with the push-pull wire feeding device through a wire feeder execution control circuit, the push-pull wire feeding device is connected with a welding wire, and the push-pull wire feeding device can realize variable speed movement of the welding wire; and through the synergistic effect of the variable speed movement of the welding wire and pulsed laser, stable welding of a workpiece is realized. The synergistic effect of the variable speed movement of the welding wire and pulsed laser makes the welding quality of the obtained welding layer good, and can realize the development demand of laser coaxial wire feeding welding to high power and high efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of 3D printing technology, in particular, to a laser coaxial wire feeding cladding system and process. BACKGROUND

[0002] Additive manufacturing (3D printing) is one of the key special projects of the national key research and development plan in the field of manufacturing. In recent years, additive manufacturing technology has obtained numerous engineering applications in the fields of aerospace, transportation, and biological engineering. China has become one of the countries with the fastest development and application of additive manufacturing technology.

[0003] Laser coaxial wire feeding cladding (3D printing) is a hollow treatment of high-quality laser. The metal wire to be cladded is sent to the vicinity of the laser focal point from the hollow laser beam. The high-density laser power near the focal point melts and deposits the metal wire (metal wire or welding wire), realizing cladding. Compared with selective laser melting (SLM) and laser powder deposition (LMD), laser coaxial wire feeding cladding can use wire (or welding wire) for cladding, which not only does not need expensive 3D printing powder, but also can use metal wire with lower cost. At the same time, the material utilization rate of printing is greatly improved, and the comprehensive cost is greatly reduced. Compared with arc printing (WAAM), it has the advantages of better light source quality and more stable cladding quality. Therefore, laser coaxial wire feeding cladding has unique advantages in large metal workpiece printing, short process manufacturing of design prototypes, and additive manufacturing of metal grades without commercialized printing powder, and is one of the important directions of future additive technology development.

[0004] Laser coaxial wire feeding cladding not only inherits the high-quality heat source advantage of laser cladding, but also has the low-cost and high-efficiency advantage of wire melting cladding, which is especially suitable for occasions with certain requirements on cladding quality, high requirements on cladding efficiency and cladding cost, and is suitable for fields such as shipbuilding and ocean engineering, rail transportation, and engineering machinery. It is one of the key development directions of future metal additive manufacturing.

[0005] Currently, laser coaxial wire feeding welding usually adopts the mode of constant laser power combined with constant wire feeding speed for welding. This working mode is only suitable for small power (≤2500W) and low wire feeding speed (2.5m / min) welding, and the welding process window is narrow. When the laser power and the wire feeding speed are further increased, frequent back-burning of the welding nozzle, frequent wire breakage, and molten pool overflow and other quality defects will occur, which seriously affects the overall welding efficiency and welding quality, and limits the further development of the high efficiency of this technology. At the same time, for metals with large surface tension, such as titanium alloy and nickel-based alloy, the larger surface tension requires higher stability for droplet transfer. The fluctuation of energy distribution will disrupt the stable transfer and cause defects such as back-burning and wire breakage. Taking titanium alloy as an example, when the laser power is increased to 2400W and the wire feeding speed is 2m / min, the continuous liquid bridge transfer will become very unstable, and continuous wire breakage and molten pool overflow will occur, resulting in a significant decrease in welding quality and welding efficiency. The above technical bottlenecks seriously restrict the development of laser coaxial wire feeding welding towards high power and high efficiency, and limit its application in high-end fields such as titanium alloy, hindering the development of the industry. SUMMARY

[0006] Therefore, the present application aims to provide a laser coaxial wire feeding welding system and process to solve the problem that the laser coaxial wire feeding welding in the prior art under the mode of constant laser power combined with constant wire feeding speed seriously restricts the development of laser coaxial wire feeding welding towards high power and high efficiency, limits its application in high-end fields such as titanium alloy, and hinders the development of the industry.

[0007] To achieve the above-mentioned purposes, the technical solution of the present application is as follows:

[0008] A laser coaxial wire feeding welding system, comprising a control system, a wire feeder mechanism, a motion execution mechanism, and a laser mechanism, wherein the control system is used to control the wire feeder mechanism, the motion execution mechanism, and the laser mechanism;

[0009] The wire feeder mechanism comprises a push-pull wire feeder and a push-pull wire feeding device, the control system is connected to the push-pull wire feeder through a wire feeder control line, the push-pull wire feeder is connected to the push-pull wire feeding device through a wire feeder execution control line, a wire feeding conduit is arranged between the push-pull wire feeder and the push-pull wire feeding device, and the push-pull wire feeding device is connected to the welding wire, wherein the push-pull wire feeding device can realize variable speed motion of the welding wire;

[0010] The laser mechanism comprises a fiber laser, a transmission fiber, and a welding torch, the control system is connected to the fiber laser through a laser control line, the welding torch is connected to the fiber laser through the transmission fiber, and the welding torch can emit pulsed laser under the action of the fiber laser, so as to realize stable welding of the workpiece through the synergistic effect of the variable speed motion of the welding wire and the pulsed laser.

[0011] The setting can realize the coordinated operation of each component and improve the automation degree and stability of the whole system through the control of the wire feeder mechanism, the motion execution mechanism and the laser mechanism by the control system. The stable deposition of the deposition workpiece is realized through the coordinated action of the variable speed movement of the welding wire and the pulsed laser, and the deposition layer has good welding quality. Moreover, the laser coaxial wire feeding deposition can meet the demand of developing towards high power and high efficiency, broaden the application of laser coaxial wire feeding deposition in high-end fields such as titanium alloy, and has great industry development prospect.

[0012] Further, the motion execution mechanism comprises a motion mechanism and a following protection device, the control system is connected with the motion mechanism through a motion control line, and the upper end surface of the motion mechanism is provided with a deposition workpiece. The deposition workpiece realizes stable deposition under the coordinated action of the pulsed laser and the variable speed movement of the welding wire.

[0013] The setting can effectively improve the quality and efficiency of the deposition workpiece and reduce the heat-affected zone on the surface, thereby improving the mechanical properties and service life.

[0014] A laser coaxial wire feeding deposition process uses the above-mentioned laser coaxial wire feeding deposition system, and the laser coaxial wire feeding deposition system has a pulse mode and comprises the following steps:

[0015] S1: obtaining a deposition workpiece and placing the deposition workpiece on a motion execution mechanism;

[0016] S2: starting the system and setting the laser output to a pulse mode;

[0017] S3: determining the variable speed movement form of the welding wire, determining the process parameters of the deposition workpiece deposition at the same time, and realizing the stable deposition of the deposition workpiece by the pulsed laser and the movement form of the welding wire.

[0018] The setting can realize high-precision, high-efficiency and high-quality metal material deposition processing, and improve the welding quality of the deposition workpiece during deposition.

[0019] Further, the variable speed movement form of the welding wire in step S3 comprises one of push-pull wire feeding, variable speed wire feeding and pulse wire feeding.

[0020] Further, when the deposition workpiece is one of titanium alloy, nickel alloy and stainless steel, the variable speed movement form of the welding wire is push-pull wire feeding.

[0021] Further, when the deposition workpiece is one of carbon steel, low alloy steel and aluminum alloy, the variable speed movement form of the welding wire is variable speed wire feeding or pulse wire feeding.

[0022] Further, when the variable speed movement form of the welding wire is pulse wire feeding, the process parameters of the deposition workpiece deposition are peak power P p3500~4000W, base power P b 1000~2000W, peak time is 1.5~3 times of base time, pulse frequency is 2~4Hz, and the wire feeding speed during the peak time of the laser is set to 3.5~4.5m / min.

[0023] The parameter setting of the laser coaxial wire feeding welding process in the setting can ensure the welding quality and efficiency of the welded workpiece surface, and realize the development of the laser coaxial wire feeding welding to a high-power direction.

[0024] Further, when the variable speed movement form of the welding wire is variable speed wire feeding, the process parameters for welding the welded workpiece are peak power P p 3500~4000W, base power P b 1000~2000W, peak time is 1.5~3 times of base time, pulse frequency is 2~4Hz, and the wire feeding speed during the peak time of the laser is set to 3.5~4.5m / min.

[0025] The parameter setting of the laser coaxial wire feeding welding process in the setting can ensure the welding quality and efficiency of the welded workpiece surface, and realize the development of the laser coaxial wire feeding welding to a high-power direction.

[0026] Further, when the variable speed movement form of the welding wire is push-pull wire feeding, the process parameters for welding the welded workpiece are peak power P p 3000~4000W, base power P b 1000~2000W, peak time is 1.5~3 times of base time, pulse frequency is 1~3Hz, and the wire feeding speed during the peak time of the laser is set to 3~4m / min, and the wire feeding speed during the base time of the laser is set to -0.5~-0.2m / min.

[0027] The parameter setting of the laser coaxial wire feeding welding process in the setting can ensure the welding quality and efficiency of the welded workpiece surface, and realize the development of the laser coaxial wire feeding welding to a high-power direction.

[0028] Further, a TA2 welding wire with a diameter of 1.2mm is adopted.

[0029] Compared with the prior art, the laser coaxial wire feeding welding system and process has the following advantages:

[0030] (1) The present application can realize the coordinated operation of each component and improve the automation degree and stability of the whole system by controlling the wire feeder mechanism, motion execution mechanism and laser mechanism through the control system; the stable deposition of the deposited workpiece is realized through the coordinated action of the variable speed movement of the welding wire and the pulse laser, the welding quality of the deposited layer is good, and the laser coaxial wire feeding deposition can also realize the development demand of high power and high efficiency, broaden the application of laser coaxial wire feeding deposition in high-end fields such as titanium alloy, and has great industry development prospect;

[0031] (2) For the metal with large surface tension such as titanium alloy and nickel-based alloy, under the synergistic action of the variable speed movement form of pulse laser and welding wire, stable deposition can be realized at the peak value of laser, and the wire feeding nozzle can be avoided to be stuck or back-burned; at the base value of laser, the welding wire is retracted by the system, and passive transition is changed to active transition, so that the cooling of the molten pool and the wire feeding nozzle is realized; the cold and hot alternation of the deposition process is realized through the cooperation of pulse laser and push-pull wire feeding, so that the deposition process is always in a dynamic controllable state, and the quality of the deposition process is improved; at the same time, the frequency of deposition interruption is reduced from 10 times / m to 1-2 times / m, which ensures the consistency and stability of the deposition process;

[0032] (3) For the laser coaxial deposition of ordinary metals such as carbon steel and alloy steel, based on the synergistic efficient deposition of pulse laser and pulse wire feeding / variable speed wire feeding, the heat accumulation and imbalance of the deposition process are optimized in time and space, the average wire feeding speed is improved, the original process window is expanded, and efficient deposition is realized; the process can increase the deposition efficiency by 10-20% on the basis of traditional process, while ensuring high-quality stable deposition;

[0033] (4) The push-pull wire feeding, pulse wire feeding and variable speed wire feeding used in the present application can realize periodic vibration of the molten pool when feeding the wire, provide good boundary conditions for the escape of porosity defects, reduce the porosity rate, and at the same time, the periodic vibration can realize grain crushing during the crystallization process of the molten pool, avoid grain growth, realize fine grain strengthening, and improve the deposition quality. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a structure diagram of a laser coaxial wire feeding deposition system of the present application;

[0035] Figure 2 is a push-pull wire feeding coordination timing diagram under the variable speed movement form of pulse laser and welding wire of the present application;

[0036] Figure 3 is Figure 2 Typical three stages in the metal deposition process;

[0037] Figure 4 is a pulse wire feeding or variable speed wire feeding coordination timing diagram under the variable speed movement form of metal deposition and welding wire of the present application;

[0038] Figure 5 for Figure 4 Typical two stages of pulse wire feeding in the metal deposition process of the titanium alloy of Example 1 of the present application;

[0039] Figure 6 for the titanium alloy deposition test piece of Example 1 of the present application;

[0040] Figure 7 for the titanium alloy deposition test piece of Example 2 of the present application;

[0041] Figure 8 for the titanium alloy deposition test piece of Example 3 of the present application;

[0042] Figure 9 (a) is the titanium alloy deposition test piece obtained in Comparative Example 1 Figure 1 ;

[0043] Figure 9 (b) is the titanium alloy deposition test piece obtained in Comparative Example 1 Figure 2 ;

[0044] Figure 9 (c) is the titanium alloy deposition test piece obtained in Comparative Example 1 Figure 3 .

[0045] BRIEF DESCRIPTION OF DRAWINGS

[0046] 1 - control system; 2 - wire feeder control circuit; 3 - laser control circuit; 4 - push-pull wire feeder; 5 - wire feeder execution control circuit; 6 - wire feeding conduit; 7 - fiber laser; 8 - transmission optical fiber; 9 - welding torch; 10 - hollow laser beam; 11 - push-pull wire feeding device; 12 - welding wire; 13 - motion mechanism; 14 - motion control circuit; 15 - follow-up protection device; 16 - deposition workpiece. DETAILED DESCRIPTION

[0047] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings.

[0048] When laser coaxial wire feeding deposition of metals such as titanium alloy, nickel-based alloy, etc. with large surface tension is carried out, the large liquid metal surface tension will cause uneven melting of the welding wire. When the laser energy density is low, slight external disturbance will cause the welding wire to be insufficiently capable of obtaining laser energy, and the wire feeding speed will be greater than the melting speed, which will cause frequent wire sticking and wire breaking, forming defects. When the laser energy density is high, the molten pool is too large, the high temperature in the molten pool area lasts for a long time, the melting speed is greater than the wire feeding speed, which will cause the wire feeding nozzle to be back-burned, forming a spherical metal, which will stick to the wire feeding nozzle or burn the wire feeding nozzle, forming a defect, resulting in an increase in the wire feeding resistance. At this time, a new wire feeding nozzle needs to be replaced, which will interrupt the deposition.

[0049] For the above problems, whether it is a wire or a back-burning, it will interrupt the welding, restart, not only easy to form defects at the arc break, but also greatly reduce the welding efficiency by replacing the wire feeder or teaching the new welding starting point. In order to solve the above problems, the application is proposed.

[0050] In order to improve the laser coaxial wire feeding welding quality of titanium alloy and other metals with large surface tension, improve the stability of the welding process, and expand the laser coaxial wire feeding welding efficiency in other metal fields and expand the stable working process window, the scheme starts from the cooperation of laser energy output and wire feeding. First, pulse laser is used to realize precise control of laser energy in the welding process. The peak energy is used to quickly melt the welding wire, and the base energy is used to reduce the temperature of the molten pool to avoid back-burning and expand the welding process window. At the same time, pulse wire feeding or push-pull wire feeding is used. In the peak stage of laser output, the welding wire is fed at a high speed, and in the tail of the peak, the welding wire is stopped or forced to pull back to realize semi-forced or forced transition, change passive transition to active transition, improve transition stability, realize high-quality welding, and expand the process window.

[0051] By realizing the cooperation of laser energy output and wire feeding, the time domain and space of laser energy are reasonably and accurately distributed. For metals with large surface tension, push-pull wire feeding is used to change passive transition to active transition and realize cooperation with laser energy. For other metals, in order to realize efficient welding and expand the process window, pulse wire feeding or variable-speed wire feeding is used. In the laser peak area, high laser power and wire feeding speed are used to realize efficient welding. In the laser base area, low wire feeding speed or stop wire feeding is used for cooling to avoid back-burning and molten pool overflow. Through the above improvements, the laser coaxial wire feeding welding process window can be expanded, and the welding quality of titanium alloy and other metals with large surface tension can be improved to realize high-quality welding.

[0052] Specifically, as shown in Figures 1-8 The present application relates to a laser coaxial wire feeding welding system, which comprises a control system 1, a wire feeder mechanism, a motion execution mechanism, and a laser mechanism. The control system 1 is used to control the wire feeder mechanism, the motion execution mechanism, and the laser mechanism.

[0053] Specifically, the control system is mainly responsible for human-machine input, laser output control, wire feeding output control, and motion control. Unlike traditional control systems, the laser output control can realize cooperative coupling with the wire feeding output control to realize the cooperation of laser power output and wire feeding speed.

[0054] The wire feeder mechanism includes a push-pull wire feeder 4 and a push-pull wire device 11, the push-pull wire feeder 4 is connected with the push-pull wire device 11 through a wire feeder execution control line 5, and a wire feeding pipe 6 is further arranged between the push-pull wire feeder 4 and the push-pull wire device 11. The wire feeding pipe can effectively protect the welding wire from being damaged, and can control the flow and speed of the welding wire. The control system 1 is connected with the push-pull wire feeder 4 through a wire feeder control line 2. The push-pull wire device can realize variable speed movement of the welding wire 12. Overall, the wire feeder mechanism can effectively realize the conveying and variable speed movement of the welding wire, adapt to various welding requirements, and improve the welding efficiency and precision.

[0055] The laser mechanism includes a fiber laser 7, a transmission fiber 8, and a welding gun 9. The control system 1 is connected with the fiber laser 7 through a laser control line 3. The welding gun 9 is connected with the fiber laser 7 through the transmission fiber 8. The welding gun 9 can emit a hollow laser beam 10, i.e. pulse laser, under the action of the fiber laser 7. Through the cooperation of the variable speed movement of the welding wire and the pulse laser, stable deposition of the workpiece is realized.

[0056] The movement execution mechanism includes a movement mechanism 13 and a following protection device 15. The control system 1 is connected with the movement mechanism 13 through a movement control line 14. The movement mechanism 13 is provided with a deposition workpiece 16 on the upper end face. Through the cooperation of the variable speed movement of the pulse laser and the welding wire, stable deposition of the deposition workpiece 16 is realized.

[0057] A laser coaxial wire feeding deposition process using the above-mentioned laser coaxial wire feeding deposition system includes the following steps:

[0058] S1: obtaining a deposition workpiece, placing the deposition workpiece on the movement execution mechanism;

[0059] S2: starting the system, setting the laser output to pulse mode;

[0060] S3: determining the variable speed movement form of the welding wire, and determining the process parameters of the deposition workpiece deposition. The stable deposition of the deposition workpiece is realized by the variable speed movement form of the pulse laser and the welding wire.

[0061] In this embodiment, the deposition workpiece is one of titanium alloy, nickel alloy and stainless steel. The variable speed form of the welding wire is push-pull wire feeding. The peak power P p =3000~4000W, the base power P b =1000~2000W, the peak time is about 1.5~3 times of the base time, the pulse frequency is 1~3Hz, and the wire feeding speed is set to 3~4m / min at the laser peak time and -0.5m / min (wire drawing mode) at the laser base time.Figure 2 As shown. When the laser output is at the peak, the larger laser power density can form a larger volume of molten pool in the base body, and a larger wire feeding speed will not form a wire pinning at this time, but the continuous high energy input will increase the risk of molten pool overflow and wire back burning, at this time, the laser output enters the base value interval, the lower laser input power density makes the molten pool smaller, and at the same time, the forward wire feeding is changed to reverse wire drawing, the wire is drawn back from the molten pool, the liquid bridge is first necked, and then the wire is separated from the molten pool, which provides good conditions for the cooling of the molten pool and the wire tip, after a period of cooling, it reenters the laser peak interval to form a cycle; this process can avoid the wire pinning or back burning of titanium alloy, nickel-based alloy and other metals with large surface tension during laser coaxial wire feeding, improve the deposition quality without reducing the deposition efficiency, avoid the interruption of deposition, and improve the overall efficiency.

[0062] When laser coaxial wire feeding deposition of carbon steel, low alloy steel and other metals is performed, the wire feeding speed is generally ≤2.5 m / min due to the limitation of the stable process window in the conventional deposition process. Further increasing the wire feeding speed will form a wire pinning due to the limitation of the energy provided by the molten pool and the laser for the wire melting, which cannot reach the wire feeding speed, and seriously affects the further improvement of the deposition efficiency. In this embodiment, the deposition workpiece is one of carbon steel and low alloy steel, the variable speed running form of the wire is pulse wire feeding, the laser output is set to pulse mode, the peak power P p =3500~4000W, the base value power is set to 1000~2000W of the peak power, the peak time is about 2 times the base time, the pulse frequency is 2~4Hz, and the wire feeding speed is set to 3.5~4.5m / min at the laser peak, and the wire feeding speed is set to 0~1m / min at the laser base value. When it is set to 0, it is pulse wire feeding at this time; when it is set to a lower speed, it is variable speed wire feeding at this time, such as Figure 4 As shown. When the laser output is at the peak, the larger laser power will ensure a larger molten pool for efficient deposition, which provides a larger energy for the wire melting, but as the temperature around the molten pool continues to increase, the risk of wire feeding nozzle burning will continue to rise, at this time, the laser enters the base value stage quickly, the laser power is low, the size of the molten pool is reduced, and at the same time, the wire feeding speed is reduced to 0~1m / min to avoid wire pinning, and the temperature around the molten pool is reduced in time and space to enter the cooling stage, after a period of cooling, it reenters the laser peak interval to form a cycle; this process can increase the deposition efficiency by 10~20% based on the traditional process while ensuring stable high-quality deposition.

[0063] The push-pull wire feeding in the embodiment refers to the wire feeding in the first direction and the second direction opposite to the first direction, and the wire feeding in the first direction and the second direction is alternately performed, the first direction is a positive direction, and the speed of the first direction is greater than the absolute value of the speed of the second direction, and the moving distance of the wire in the first direction is greater than the moving distance of the wire in the second direction in one movement.

[0064] The variable-speed wire feeding in the embodiment refers to the wire feeding in one direction, and the continuous variable-speed wire feeding process includes the speed of the laser peak value and the speed of the laser base value, and the speed of the laser peak value of the variable-speed wire feeding is greater than the speed of the laser base value.

[0065] The pulse wire feeding in the embodiment refers to the wire feeding in one direction, and the wire feeding process is intermittent, and the wire feeding speed in the laser peak value is greater than the wire feeding speed in the laser base value.

[0066] The continuous laser in the embodiment refers to a laser beam continuously radiated at a constant power and frequency. Its output power is constant in time, so the energy emitted per second is continuous. Continuous laser is suitable for applications that require continuous and stable output, such as laser printers, laser cutting machines, laser therapy, etc.

[0067] The pulse laser in the embodiment refers to a laser beam radiated in the form of a short pulse. Its output power has obvious pulsatility in time, and energy is usually released in the form of high-energy short pulses. Pulse laser is suitable for applications that require high energy and short pulses, such as laser radar, laser range finder, laser inkjet printer, etc.

[0068] Embodiment 1

[0069] In the embodiment, titanium alloy laser coaxial wire feeding deposition (push-pull wire feeding) is performed, and the wire feeding is performed using a 1.2 mm diameter TA2 wire. The laser output is set to pulse mode, the peak power is set to P p =3500W, the base power is set to P b =2000W, the peak time is about twice the base time, the pulse frequency is 2Hz, the wire feeding speed at the laser peak value is set to 3.5m / min, and the wire feeding speed at the laser base value is set to -0.5m / min. The deposition effect is shown in Figure 6 , the deposition process is stable, and no wire feeding nozzle burning is found, and the deposition is interrupted twice. After welding, the samples are subjected to X-ray detection according to NB / T47013.2, and all meet the level II.

[0070] Embodiment 2

[0071] The scheme is used for laser coaxial wire feeding part printing of TC3 titanium alloy, a 1.2 mm diameter TC3 welding wire is used, the laser output is set to pulse mode, in order to realize long time continuous printing, the peak power is set to P p =3000 W, the base power is set to P b =1000 W, the peak time is about 3 times of the base time, the pulse frequency is 2 Hz, at the same time, the wire feeding speed at the laser peak time is set to 3 m / min, the wire feeding speed at the laser base time is set to -0.2 m / min, the deposition effect is as shown in Figure 7 , the deposition process is stable, long time continuous deposition is realized, the formed product is smooth and has good continuity, after mechanical processing of the formed product, no surface defects are found, and the penetration detection meets the NB / T47013 level I.

[0072] Example 3

[0073] The scheme is used for laser coaxial wire feeding part printing of carbon steel, a 1.2 mm diameter ER50-6 welding wire is used, the peak power is set to P p =3600 W, the base power is set to P b =1500 W, the peak time is about 2 times of the base time, the pulse frequency is 3 Hz, at the same time, the pulse wire feeding mode is used, the wire feeding speed at the laser peak time is set to 4 m / min, the printing effect is as shown in Figure 8 , the path intersection part is excessively smooth, no wire breakage and flow occurs in the whole deposition process, and the penetration detection meets the NB / T47013 level I.

[0074] Comparative Example 1

[0075] The conventional laser coaxial wire feeding deposition technology is used, the coating is deposited by the mode of constant laser power and constant wire feeding speed, titanium alloy is used as the coating, the constant laser power is used, the specific parameters are as follows: the laser power is 2400 W, the wire feeding speed is constant and is 2 m / min, the welded structure is as shown in Figure 9 , wire breakage occurs in the whole deposition process as shown in Figure 9 (b), molten pool overflow as shown in Figure 9 (c), back burning of the welding nozzle as shown in Figure 9 (a), after welding, the sample is subjected to the X-ray detection according to the multi-layer NB / T47013.2, the level is III, and the defects are large.

[0076] It can be known from the example 1 to the example 3 and the comparative example 1 that, by the coordinated action of the variable speed movement form of the welding wire and the pulse laser, the deposition process is more stable, the quality defects of the welded coating are small, the laser coaxial wire feeding deposition can realize the development demand of high power and high efficiency, the laser coaxial wire feeding deposition is applied to the high-end field such as titanium alloy, and has great industry development prospect.

[0077] Although the present application has been disclosed with reference to the above examples, it is not intended to limit the present application. Any person skilled in the art, without departing from the spirit and scope of the present application, can make various changes and modifications, and the scope of protection of the present application should be limited by the scope defined in the claims.

Claims

1. A laser coaxial wire feeding deposition process using a laser coaxial wire feeding deposition system having a pulsed mode, characterized in that, The laser coaxial wire feeding cladding system comprises a control system, a wire feeder mechanism, a motion execution mechanism and a laser mechanism, wherein the control system (1) is used to control the wire feeder mechanism, the motion execution mechanism and the laser mechanism; The wire feeder mechanism comprises a push-pull wire feeder (4) and a push-pull wire feeding device (11), the control system (1) is connected with the push-pull wire feeder (4) through a wire feeder control line (2), the push-pull wire feeder (4) is connected with the push-pull wire feeding device (11) through a wire feeder execution control line (5), a wire feeding conduit (6) is arranged between the push-pull wire feeder (4) and the push-pull wire feeding device (11), the push-pull wire feeding device (11) is connected with a welding wire (12), and the push-pull wire feeding device (11) can realize variable speed movement of the welding wire (12); The laser mechanism comprises a fiber laser (7), a transmission fiber (8) and a welding torch (9), the control system (1) is connected with the fiber laser (7) through a laser control line (3), the welding torch (9) is connected with the fiber laser (7) through the transmission fiber (8), and the welding torch (9) can emit pulsed laser under the action of the fiber laser (7), so that the workpiece is stably cladded through the synergistic effect of the variable speed movement of the welding wire and the pulsed laser; The laser coaxial wire feeding cladding process comprises the following steps: S1: obtaining a cladded workpiece and placing the cladded workpiece on the motion execution mechanism; S2: starting the system and setting the laser output as a pulse mode; S3: determining the variable speed movement form of the welding wire and the process parameters of the cladded workpiece cladding, and realizing the stable cladding of the workpiece through the variable speed movement form of the pulsed laser and the welding wire; The variable speed movement form of the welding wire in step S3 comprises one of push-pull wire feeding, variable speed wire feeding and pulse wire feeding; When the cladded workpiece is one of titanium alloy, nickel alloy and stainless steel, the variable speed movement form of the welding wire is push-pull wire feeding; When the variable speed movement of the welding wire is push-pull wire feeding, the process parameters of the welding workpiece welding are peak power P p 3000-4000 W, base power P b 1000-2000 W, peak time is 1.5-3 times of base time, pulse frequency is 1-3 Hz, at the same time, the wire feeding speed during the peak of the laser is 3-4 m / min, and the wire feeding speed during the base of the laser is -0.5--0.2 m / min.

2. A laser coaxial wire feeding welding process as claimed in claim 1, wherein, The motion execution mechanism comprises a motion mechanism (13) and a following protection device (15), the control system (1) is connected with the motion mechanism (13) through a motion control line (14), an upper end surface of the motion mechanism (13) is provided with a cladded workpiece (16), and the cladded workpiece (16) is stably cladded under the synergistic effect of the pulsed laser and the variable speed movement form of the welding wire.

3. A laser coaxial wire feeding welding process as claimed in claim 1, wherein, When the cladded workpiece is one of carbon steel, low alloy steel and aluminum alloy, the variable speed movement form of the welding wire is variable speed wire feeding or pulse wire feeding.

4. A laser coaxial wire feeding welding process as claimed in claim 3, wherein, When the variable speed movement form of the welding wire is pulse wire feeding, the process parameters of the fused workpiece are peak power P p 3500-4000 W, base power P b 1000-2000 W, peak time is 1.5-3 times of base time, pulse frequency is 2-4 Hz, at the same time, the wire feeding speed at the peak of the laser is set to 3.5-4.5 m / min, and the wire feeding speed at the base of the laser is set to 0.

5. A laser coaxial wire feeding welding process as claimed in claim 3, wherein, When the variable speed movement form of the welding wire is variable speed wire feeding, the process parameters of the fused workpiece are peak power P p 3500-4000 W, base power P b 1000-2000 W, peak time is 1.5-3 times of base time, pulse frequency is 2-4 Hz, at the same time, the wire feeding speed at the peak of the laser is set to 3.5-4.5 m / min, and the wire feeding speed at the base of the laser is set to 0-1 m / min.

6. A laser coaxial wire feeding welding process as claimed in claim 5, wherein, TA2 welding wire with a diameter of 1.2 mm is adopted.

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