Laser welding method, apparatus and welding tip

Abstract

This application discloses a laser welding method, equipment, and welding nozzle. The laser welding method includes the following steps: selecting welding powder according to the material properties of the workpiece; conveying welding powder toward the laser beam and recovering part of the welding powder; controlling the laser beam to move along a preset trajectory to weld the workpiece. During the welding process, by conveying welding powder to the laser beam, the welding powder melts under the action of the laser beam and combines with the welding area of ​​the workpiece. At the same time, the escaped welding powder is further recovered to avoid welding powder contamination of the workpiece and welding equipment, and also to prevent welding powder from escaping into the laser beam path and affecting laser transmission and welding quality.

Description

Technical Field

[0001] This application relates to the field of laser processing equipment, and in particular to a laser welding method, equipment and welding nozzle. Background Technology

[0002] Compared to traditional welding techniques, laser welding technology offers advantages such as controllable heat input, a small heat-affected zone, high welding speed, high efficiency, minimal deformation, and excellent beam reachability—features unmatched by other traditional heat sources. Adding alloying elements during the welding process not only stabilizes the process but also acts as a bridge between the materials being welded, facilitating metal-to-metal bonding. Furthermore, the alloying element ratio can be effectively adjusted. However, in related technologies, alloying processes like laser cladding or spray welding result in dispersed welding powder, which can interfere with light path transmission, leading to instability in the laser processing. The dispersed welding powder can also negatively impact the production environment. Summary of the Invention

[0003] This application proposes a laser welding method, equipment, and welding nozzle, in which the transmission of welding powder does not affect the laser beam path, resulting in more stable welding quality.

[0004] To achieve the above objectives, this application proposes a laser welding method, comprising the following steps:

[0005] Select welding powder according to the material properties of the workpiece;

[0006] It delivers welding powder toward the laser beam and recovers some of the welding powder;

[0007] The laser beam is controlled to move along a preset trajectory to weld the workpiece.

[0008] In some embodiments, in the step of conveying welding powder toward the laser beam, the laser beam comprises an outer ring laser and an inner core laser, and the power density of the outer ring laser is 3-5 x 10⁻⁶. 5 W / cm 2 The power density of the core laser is 6.4-12.7 x 10⁻⁶. 6 W / cm 2 .

[0009] In some embodiments, in the step of conveying solder powder toward the laser beam, the solder powder is conveyed by jet gas, and the gas used to convey the solder powder includes an inert gas.

[0010] In some embodiments, in the step of conveying welding powder toward the laser beam, the welding powder is conveyed by jetting, and the gas carrying the welding powder forms a spiral airflow around the laser beam.

[0011] In some embodiments, in the step of recovering a portion of the solder powder, the solder powder is recovered by negative pressure suction.

[0012] This application also proposes a welding nozzle, comprising:

[0013] A base for connecting to a laser, the base having a first channel for the laser beam to pass through;

[0014] A powder feeding assembly for conveying welding powder to a laser beam, the powder feeding assembly including a powder feeding tube disposed on the base;

[0015] A powder suction assembly is used to suction welding powder output from the powder conveying pipe, the powder suction assembly including a powder suction pipe disposed on the base.

[0016] In some embodiments, the welding nozzle further includes a powder gathering element disposed on one side of the base, the powder gathering element having a second channel for the laser beam to pass through; the second channel is respectively connected to the powder suction tube and the powder delivery tube.

[0017] In some embodiments, one end of the powder conveying pipe and the powder suction pipe is disposed on the base, and the other end of the powder conveying pipe and the powder suction pipe are respectively connected to the powder gathering member and respectively disposed on both sides of the powder gathering member.

[0018] In some embodiments, the end of the powder conveying pipe and / or the powder suction pipe away from the base is arranged at an angle to the inner wall of the powder gathering member to form a spiral airflow in the second channel.

[0019] In some embodiments, the welding nozzle further includes a cooling assembly comprising cooling pipes disposed on the base.

[0020] This application also proposes a laser welding device, including the aforementioned welding nozzle and a laser, the laser being used to emit a laser beam.

[0021] This application also proposes a laser welding apparatus for performing the steps of the laser welding method described above.

[0022] The advantages of this embodiment are as follows: During the welding process, welding powder is fed into the laser beam, where it melts and bonds with the welding area of ​​the workpiece under the action of the laser beam. Simultaneously, any escaped welding powder is further recovered, preventing contamination of the workpiece and welding equipment, and also preventing welding powder from escaping into the laser beam path and affecting laser transmission and welding quality. Attached Figure Description

[0023] Figure 1 This is a flowchart of a laser welding method in one embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the welding nozzle structure in one embodiment of this application;

[0025] Figure 3This is a schematic diagram of the welding nozzle structure in another embodiment of this application;

[0026] Figure 4 This is a schematic diagram of the welding nozzle structure in another embodiment of this application;

[0027] Figure 5 This is a schematic diagram of the structure of a laser welding device in one embodiment of this application;

[0028] Figure 6 for Figure 5 A magnified view of a portion of point A in the embodiment.

[0029] Label Explanation:

[0030] 10. Base; 11. First channel; 12. Connector;

[0031] 21. Powder conveying pipe; 31. Powder suction pipe;

[0032] 40. Powder-collecting component; 41. Second channel;

[0033] 50. Cooling assembly; 51. Cooling inlet; 52. Cooling outlet;

[0034] 60. Laser beam; 61. Inner core laser; 62. Outer ring laser;

[0035] 70. Laser;

[0036] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0037] The solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments in this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0038] It should be noted that all directional indications in the embodiments of this application, such as up, down, left, right, front, back, etc., are only used to explain the relative positional relationship and movement of the components in a specific posture as shown in the attached figure. If the specific posture changes, the directional indication will also change accordingly.

[0039] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0040] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0041] This application proposes a laser welding method, referring to... Figures 1 to 4 The laser welding method includes:

[0042] S10. Select welding powder according to the material properties of the workpiece. Workpieces are generally made of the same type of metal, such as steel, aluminum alloy, or copper, but can also be made of different types of metal. Therefore, welding involves welding different metals. Welding powder is generally an alloy powder, and different welding powders are selected according to different materials. For example, when laser welding aluminum alloys, Al-Mg-Si alloys are typical eutectic alloys, which are prone to hot cracking. This is mainly because low-melting-point eutectics such as Al-Si, Mg-Si, and Al-Mg2Si are formed at the grain boundaries during weld metal crystallization. The fragile bonding surface, under the action of transverse shrinkage and tensile stress, forms long longitudinal cracks that crack along the weld centerline. The weldability of aluminum alloys depends on the alloy type and is strongly affected by the chemical composition of the weld zone. The weld exhibits the greatest crack susceptibility when the Mg2Si content is approximately 1 wt.%. By using appropriate alloying processes to change the chemical composition of the molten pool, solidification cracks in high-strength aluminum alloys can be effectively avoided. For example, aluminum-silicon coatings have become the most widely used coating for hot-formed steel due to their advantages such as high temperature resistance, low density, wear resistance, high thermal conductivity, and low coefficient of thermal expansion. When laser welding is used, the coating melts into the weld at the weld joint, generating a significant amount of delta ferrite, which severely reduces the mechanical properties of the weld joint. Especially for hot-formed steels with aluminum-silicon coatings at 1500 MPa and above, achieving post-weld tensile strength and elongation levels comparable to the base material is extremely difficult. By using appropriate alloying processes to control and optimize the joint microstructure, the formation of delta ferrite at the weld can be suppressed, allowing the joint performance after hot stamping to be consistent with that of the base material.

[0043] S20. Convey welding powder toward the laser beam 60 and recover some of the welding powder. In this step, welding powder can be conveyed by a spiral conveyor. The welding powder can be stored in a powder hopper. A powder conveying pipe 21 is set at the lower end of the powder hopper, and a spiral rod is set in the pipe. The spiral rod is located at the lower end of the powder hopper. The spiral rod can be rigid or flexible, and a motor drives the spiral rod to rotate, outputting a quantitative amount of welding powder. The end of the powder conveying pipe 21 away from the powder hopper is aligned with the focal point of the laser beam 60. During the welding process, the output welding powder directly reaches the focal point, which can make the welding powder melt quickly and improve welding efficiency. As for the welding powder recovery, a negative pressure recovery method is adopted. A powder suction pipe 31 can be set. One end of the powder suction pipe 31 faces the focal point of the laser beam 60, and the other end is connected to the negative pressure generator. During the transmission of welding powder and laser welding, welding powder will inevitably be stirred up or scattered. The welding powder in the non-welding area can be vacuumed by the powder suction pipe 31 to prevent the welding powder from rising into the laser beam path, affecting the laser transmission, and thus causing unstable welding quality. Alternatively, a protective cover can be installed at the lower end of the laser welding nozzle to prevent welding powder from escaping, thereby improving the powder absorption efficiency.

[0044] S30. Control the laser beam 60 to move along a preset trajectory to weld the workpiece. In this step, the laser beam 60 is emitted by a laser source and can be driven by a drive mechanism to move along a set trajectory, thus causing the laser beam 60 to move along the same trajectory. Alternatively, optical components can be used to make the laser beam 60 oscillate during welding. The aforementioned trajectory can be a wavy line or a spiral line. The oscillation of the laser beam 60 can prolong the residence time of the molten pool, which is beneficial for the stirring and mixing of the alloying powder and the base material in the molten pool, thereby effectively controlling the composition of the weld joint and improving the performance of the weld joint. Compared with existing laser welding technologies, this method produces aesthetically pleasing welds without welding defects such as cracks, porosity, incomplete penetration, or lack of fusion. The welding process is stable, and the welding process performance is excellent.

[0045] In the above steps, welding powder is fed into the laser beam 60, causing it to melt and bond with the welding area of ​​the workpiece under the action of the laser beam 60. Simultaneously, any escaped welding powder is further recovered, preventing contamination of the workpiece and welding equipment, and also preventing welding powder from escaping into the laser beam path and affecting laser transmission and welding quality. Synchronous powder feeding and collection greatly improves welding powder utilization and eliminates dust that could negatively impact the production environment.

[0046] In some embodiments, refer to Figures 1 to 4 In the step of conveying welding powder toward the laser beam 60, the laser beam 60 includes an outer ring laser 62 and an inner core laser 61, and the power density of the outer ring laser 62 is 3-5 x 10⁻⁶. 5 W / cm 2 The power density of the core laser 61 is 6.4-12.7 x 10⁻⁶. 6 W / cm2 In this step, the outer ring laser 62 and the inner core laser 61 can be coaxially arranged. The power density of the inner core laser 61 is greater than that of the outer ring laser 62. During the welding process, the welding powder melts when it passes through the outer ring laser 62 and does not enter the optical path of the inner core laser 61. Therefore, the outer ring laser 62 acts as a shielding field, preventing the welding powder from affecting the optical path of the inner core laser 61. At the same time, the inner core laser 61 has a higher power density, which can be used to melt the material on the workpiece. The molten welding powder falls into the welding area and mixes with the molten material on the workpiece to achieve the welding effect. Setting up two layers of lasers for separate operation can further improve the welding quality and welding efficiency, and the overall power consumption of the laser beam 60 is lower.

[0047] In some embodiments, refer to Figures 1 to 4 In the step of conveying welding powder toward the laser beam 60, the welding powder is conveyed by air jet, and the gas used to convey the welding powder includes an inert gas. In this step, the particle size of the welding powder is 40-150 μm to facilitate air jet conveying. A gas pipe can be installed on the powder conveying pipe 21, with one end connected to the powder conveying pipe 21 and the other end connected to a gas tank. The gas flow rate of the gas pipe is adjusted by a pressure valve. After the gas is ejected, it enters the powder conveying pipe 21 to carry the welding powder out of the nozzle of the powder conveying pipe 21. The nozzle of the powder conveying pipe 21 faces the focal point of the laser beam 60, and the ejected welding powder can be evenly distributed in the welding area of ​​the workpiece, avoiding uneven distribution of welding powder that would affect the welding quality.

[0048] Understandably, a ring can be set around the outer periphery of the laser beam, with the laser beam passing through the center of the ring. When the solder powder is carried into the ring by the airflow from the powder supply pipe 21, a spiral airflow is formed. Under the action of the airflow, the solder powder is moved away from the center of the ring due to centrifugal force, while avoiding entering the optical path of the inner core laser 61, thus accumulating in the annular laser region around the inner core laser 61. Due to the airflow, the solder powder stays in the outer ring laser 62 for a longer time, improving the solder powder utilization rate. The opening of the powder suction pipe 31 is set above the powder supply port to collect the rising solder powder. In addition, the upper opening of the ring can be narrowed to reduce the escape of solder powder.

[0049] When butt welding aluminum-silicon coated materials, a continuous fiber laser can be used to emit a laser beam 60. The incident laser power of the inner core laser 61 is P = 1900W, and the incident laser power of the outer ring laser 62 is P = 1000W. The defocusing amount f = +10, and the initial position of the laser is set on the part of the aluminum-silicon coated material to be welded. The laser beam 60 is controlled to move from the center line of the joint along the length of the joint at a welding speed of 40mm / s (in a rotary oscillation manner) to weld the joint. The oscillation amplitude of the laser beam 60 is Amp = 1.0mm, the oscillation frequency is Freq = 80Hz, the shielding gas is argon gas with a purity of 99.99%, the argon gas flow rate of the powder feeding component is 10L / min, and the vacuum degree of the powder suction tube 31 is 20Kpa.

[0050] This application also proposes a welding nozzle, as shown in the reference. Figures 2 to 6 The welding nozzle includes:

[0051] Base 10 for connection to laser 70, said base 10 having a first channel 11 for the laser beam to pass through;

[0052] A powder feeding assembly for conveying welding powder to a laser beam 60, the powder feeding assembly including a powder feeding tube 21 disposed on the base 10;

[0053] A powder suction assembly is used to suction the welding powder output from the powder conveying pipe 21. The powder suction assembly includes a powder suction pipe 31 disposed on the base 10.

[0054] In this embodiment, the base 10 can be a metal block, such as an aluminum alloy block or a copper block. The base 10 is used to connect to the laser 70, specifically, it can be directly connected or connected through the connector 12. The base 10 is provided with a first channel 11, and the corresponding connector 12 can be a cylindrical or conical cylinder with both ends open. One end of the connector 12 is connected to the mounting base of the laser 70 by a threaded connection or screw, and the other end of the connector 12 is connected to the base 10 by a threaded connection or screw. Thus, the laser beam 60 can pass through the connector 12 and the first channel 11 in one go and be focused on the workpiece. The powder conveying assembly can convey welding powder by a spiral conveying method. The powder conveying assembly includes a powder hopper, a powder conveying pipe 21, a spiral rod, and a motor. The welding powder can be stored in the powder hopper, and a powder conveying pipe 21 is provided at the lower end of the powder hopper. A spiral rod is provided in the pipe, and the spiral rod is located at the lower end of the powder hopper. The spiral rod can be rigid or flexible, and the motor drives the spiral rod to rotate, outputting a quantitative amount of welding powder. The powder delivery pipe 21 is mounted on the base 10, with its end furthest from the powder hopper aligned with the focal point of the laser beam 60. During welding, the output welding powder directly reaches the focal point, allowing for rapid melting and improved welding efficiency. The welding nozzle can be manufactured using 3D printing additive manufacturing technology. The nozzle is connected to the connector 12 via threads. The connector 12 is directly inserted into the welding head assembly 50 and locked with screws. Adjusting the connector 12 and the welding head assembly allows control of the distance between the welding nozzle and the base metal.

[0055] The welding powder recovery adopts a negative pressure recovery method. The powder suction component includes a powder suction tube 31 and a negative pressure generator. The powder suction tube 31 is set on the base 10, with one end facing the focal point of the laser beam 60 and the other end connected to the negative pressure generator. During the transmission of welding powder and laser welding, welding powder inevitably gets thrown up or disperses. The powder suction tube 31 can be used to remove welding powder in non-welding areas using negative pressure, preventing welding powder from rising into the laser beam path and affecting laser transmission, thus causing unstable welding quality. Alternatively, a protective cover can be set at the lower end of the laser welding nozzle to prevent welding powder from escaping, thereby improving the powder suction efficiency.

[0056] In this embodiment, welding powder is fed into the laser beam 60, causing it to melt and bond with the welding area of ​​the workpiece under the action of the laser beam 60. Simultaneously, any escaped welding powder is further recovered, preventing contamination of the workpiece and welding equipment, and also preventing welding powder from escaping into the laser beam path and affecting laser transmission and welding quality. Synchronous powder feeding and collection greatly improves welding powder utilization and eliminates dust that could negatively impact the production environment.

[0057] In some embodiments, refer to Figures 2 to 4The welding nozzle also includes a powder-gathering element 40 disposed on one side of the base 10. The powder-gathering element 40 has a second channel 41 for the laser beam to pass through. The second channel 41 is connected to the powder suction pipe 31 and the powder delivery pipe 21. The powder-gathering element 40 can be a sleeve with open ends. The sleeve can be a cylindrical or conical cylinder, and the sleeve has the second channel 41 inside. The powder-gathering element 40 can be directly connected to the base 10, or indirectly connected to the base 10 through the powder delivery pipe 21 and the powder suction pipe 31. The first channel 11 and the second channel 41 are arranged correspondingly from top to bottom, and can be arranged coaxially. When the laser beam 60 passes through the second channel 41, the welding powder enters the second channel 41 from the powder delivery pipe 21 and can be melted by the laser beam 60.

[0058] It is worth noting that the welding powder is conveyed by air jet, and the gas used to convey the welding powder includes inert gas, but air can also be used. During the conveying of the welding powder, inert gas can also be delivered to the welding area to protect it. The particle size of the welding powder is 40-150 μm to facilitate air jet conveying. A gas pipe can be installed on the powder conveying pipe 21, with one end connected to the powder conveying pipe 21 and the other end connected to a gas tank. The gas flow rate of the gas pipe is adjusted by a pressure valve. After being ejected, the gas enters the powder conveying pipe 21 to carry the welding powder out of the nozzle of the powder conveying pipe 21. The nozzle of the powder conveying pipe 21 faces the focal point of the laser beam 60, ensuring that the ejected welding powder is evenly distributed in the welding area of ​​the workpiece, avoiding uneven distribution that could affect the welding quality. The opening of the powder suction pipe 31 on the powder collecting component 40 is larger than the opening of the powder conveying pipe 21 on the powder collecting component 40 to quickly collect any scattered or scattered welding powder.

[0059] It is understood that one end of the powder conveying pipe 21 and the powder suction pipe 31 is disposed on the base 10, and the other end of the powder conveying pipe 21 and the powder suction pipe 31 are respectively connected to the powder gathering member 40 and respectively disposed on both sides of the powder gathering member 40. In this embodiment, the opening of the powder suction pipe 31 on the powder gathering member 40 is aligned with the opening of the powder conveying pipe 21 on the powder gathering member 40, so as to quickly collect the scattered or raised welding powder.

[0060] In some embodiments, refer to Figures 2 to 4Viewed along the axial direction (Z-axis or vertical direction) of the powder-collecting component 40, the end of the powder-feeding pipe 21 and / or the powder-suction pipe 31 away from the base 10 is arranged at an angle to the inner wall of the powder-collecting component 40 to form a spiral airflow within the second channel 41. In this embodiment, the angle between the powder-feeding pipe 21 and / or the powder-suction pipe 31 and the inner wall of the powder-collecting component 40 is less than 45 degrees, or it can be set to 0 degrees, thereby the powder-feeding pipe 21 and / or the powder-suction pipe 31 is arranged along the tangent of the inner wall of the powder-collecting component 40. The openings of the powder-suction pipe 31 and the powder-feeding pipe 21 on the powder-collecting component 40 can be located on the same side of the powder-collecting component 40 or on opposite sides. The opening of the powder-feeding pipe 21 is located near the middle or lower section of the powder-collecting component 40. The opening of the powder-suction pipe 31 is located near the upper section of the powder-collecting component 40. When the solder powder is injected into the powder-collecting component 40 with the airflow, the airflow forms a spiral airflow within the powder-collecting component 40. Due to centrifugal force, the solder powder moves away from the center of the powder-collecting component 40, while avoiding entering the optical path of the inner core laser 61, thus accumulating in the annular laser region around the inner core laser 61. The opening of the powder suction pipe 31 is located above the powder inlet to collect the rising solder powder. In addition, the upper opening of the powder-collecting component 40 can be narrowed to reduce the escape of solder powder.

[0061] In some embodiments, refer to Figures 2 to 4 The welding nozzle further includes a cooling assembly 50, which includes cooling pipes disposed on the base 10. In this embodiment, the cooling assembly 50 also includes a pump body communicating with the cooling pipes and a coolant. The cooling pipes pass through the base 10 and are disposed on the base 10, forming a cooling inlet 51 and a cooling outlet 52. The pump body delivers coolant to the base 10 to cool the base 10, the powder conveying pipe 21, and the powder suction pipe 31.

[0062] This application also proposes a laser welding device, referring to... Figures 2 to 6 The laser welding equipment includes the aforementioned welding nozzle and laser 70, which emits a laser beam 60. The laser welding equipment also includes a drive mechanism for driving the laser 70 and the welding nozzle; the drive mechanism can be a robotic arm or a three-axis orthogonal drive module.

[0063] This application also proposes a laser welding device, referring to... Figures 1 to 6 The laser welding equipment is used to perform the steps of the laser welding method described above.

[0064] The aforementioned laser welding equipment includes a laser 70, and the laser beam 60 emitted by the laser 70 includes an outer ring laser 62 and an inner core laser 61. The power density of the outer ring laser 62 is 3-5 x 10⁻⁶. 5 W / cm 2 The power density of the core laser 61 is 6.4-12.7 x 10⁻⁶. 6 W / cm 2During the welding process, the welding powder melts when it passes through the outer ring laser 62, preventing it from entering the optical path of the inner core laser 61. Therefore, the outer ring laser 62 acts as a shielding field, preventing the welding powder from affecting the optical path of the inner core laser 61. Simultaneously, the inner core laser 61 has a higher power density, allowing it to melt the material on the workpiece. The molten welding powder falls into the welding area and mixes with the molten material on the workpiece, achieving the welding effect. Using two layers of lasers for separate operations further improves welding quality and efficiency, and the overall power consumption of the laser beam 60 is lower. When butt welding aluminum-silicon coated materials, a continuous fiber laser 70 can be used to emit the laser beam 60, with the inner core laser 61 having an incident laser power P = 1900W and the outer ring laser 62 having an incident laser power P = 1000W. The defocusing amount f = +10, and the initial position of the laser is set on the part of the aluminum-silicon coated material to be welded; the laser beam 60 is controlled to move from the center line of the joint along the length of the joint at a welding speed of 40 mm / s (in a rotary swing manner) to weld the joint. The swing amplitude of the laser beam 60 is Amp = 1.0 mm, the swing frequency is Freq = 80 Hz, the shielding gas is argon gas with a purity of 99.99%, the flow rate of argon gas blown out by the powder feeding component is 8-10 L / min, and the vacuum degree of the powder suction tube 31 is 10-20 kPa.

[0065] The working principle of this application embodiment is as follows:

[0066] The welding powder is conveyed to the powder collecting unit 40 by the inert gas flow in the powder conveying pipe 21, where a spiral airflow is formed. The inert gas forms a protective barrier for the welding area. Due to centrifugal force, the welding powder moves away from the inner core laser 61 of the laser beam 60 passing through the powder collecting unit 40 and is melted by the outer ring laser 62, thus entering the welding area below. Welding powder that escapes due to airflow or is lifted by hot air is sucked out from the opening of the powder suction pipe 31 above. The welding powder never enters the optical path of the inner core laser 61, avoiding affecting the welding effect. Synchronous powder feeding and collection can greatly improve the utilization rate of welding powder and prevent dust from affecting the production environment.

[0067] The laser welding method and equipment provided by this invention offer the following advantages: First, the outer ring laser melts the welding powder, while the inner core laser performs the laser welding, avoiding interference from the welding powder on the laser beam and ensuring the stability of the welding process. Second, there are virtually no restrictions on the selection of welding powder; alloy welding powder that meets product requirements can be designed. Third, the composition, dilution rate, microstructure, thickness, and shape of the laser alloyed molten pool are all controllable, facilitating automation. Fourth, synchronous powder feeding and collection greatly improve the utilization rate of welding powder and prevent dust from affecting the production environment. Fifth, the swirling motion of the laser beam extends the residence time of the molten pool, which is beneficial for the mixing of welding powder and base material, thereby effectively controlling the composition of the weld joint and improving its performance. Compared with existing laser welding technologies, this method produces aesthetically pleasing welds free from defects such as cracks, porosity, incomplete penetration, and lack of fusion. The welding process is stable, and the welding performance is excellent.

[0068] The above are only some or preferred embodiments of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. A laser welding method, characterized in that, Includes the following steps: Select welding powder according to the material properties of the workpiece; Solder powder is fed toward a laser beam and a portion of the solder powder is recovered. The laser beam includes an outer ring laser and an inner core laser. The solder powder is delivered by jet, and the gas carrying the solder powder forms a spiral airflow around the outer periphery of the laser beam. The laser beam is controlled to move along a preset trajectory to weld the workpiece.

2. The laser welding method according to claim 1, characterized in that, In the step of conveying welding powder toward the laser beam, the power density of the outer ring laser is 3-5 x 10⁻⁶. 5 W / cm 2 The power density of the core laser is 6.4-12.7 x 10⁻⁶. 6 W / cm 2 .

3. The laser welding method according to claim 1, characterized in that, In the step of conveying welding powder toward the laser beam, the welding powder is conveyed by jet gas, and the gas used to convey the welding powder includes an inert gas.

4. The laser welding method according to claim 1, characterized in that, In the step of recovering part of the welding powder, the welding powder is recovered by suction under negative pressure.

5. A welding nozzle, characterized in that, include: A base for connecting to a laser, the base having a first channel for the laser beam to pass through; A powder feeding assembly for conveying welding powder to a laser beam, the powder feeding assembly including a powder feeding tube disposed on the base; A powder suction assembly is used to suction welding powder output from the powder conveying pipe, the powder suction assembly including a powder suction pipe disposed on the base; The welding nozzle also includes a powder gathering component disposed on one side of the base, the powder gathering component having a second channel for the laser beam to pass through; the second channel is connected to the powder suction tube and the powder delivery tube respectively; The end of the powder conveying pipe and / or the powder suction pipe away from the base is set at an angle to the inner wall of the powder gathering component to form a spiral airflow in the second channel.

6. The welding nozzle according to claim 5, characterized in that, One end of the powder conveying pipe and the powder suction pipe are disposed on the base, and the other end of the powder conveying pipe and the powder suction pipe are respectively connected to the powder gathering component and respectively disposed on both sides of the powder gathering component.

7. The welding nozzle according to claim 5 or 6, characterized in that, The welding nozzle also includes a cooling assembly, which includes cooling pipes disposed on the base.

8. A laser welding device, characterized in that, The invention includes a welding nozzle as described in any one of claims 5-7 and a laser, the laser being used to emit a laser beam.

9. A laser welding device, characterized in that, The steps for performing the laser welding method according to any one of claims 1-4.

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