Narrow gap welding device and method based on molten drop coaxial composite annular laser

Abstract

The invention provides a narrow gap welding device and method based on molten drop coaxial composite ring laser, and is suitable for high-precision narrow gap welding. The device comprises a welding wire melting system, an annular light beam system, a wire feeding system, a water cooling suite, a molten metal control assembly and a gas pressure system. The welding wire melting system heats a metal welding wire through an induction heating coil to generate molten drop jet flow, and the annular light beam system generates a molten pool. The molten drops vertically drop into a molten pool of the narrow-gap workpiece in a jet flow mode through the molten metal control assembly, and a high-quality welding seam is formed. The control system monitors the size of the gap in real time through the laser contour scanner and adjusts the electronic adjustable nozzle so as to control the size and flow of molten drops. The welding wire is melted through the induction heat source to generate molten drops, the problem of strong coupling between the welding wire and laser is successfully solved, heat input in the welding process is remarkably reduced, and therefore deformation and defects in narrow gap welding are reduced.

Description

Technical Field

[0001] The invention relates to the field of narrow gap welding, and in particular to a narrow gap welding device and method based on molten droplet coaxial composite ring laser. Background Art

[0002] As modern engineering machinery and national defense equipment continue to develop towards large-scale, the application of thick-walled metal materials has become more and more common. Especially in key manufacturing fields such as nuclear power equipment, tank armor, marine engineering, and ships and warships, thick-walled metal materials have become an indispensable component. In the process of welding thick-walled metal materials, narrow gap welding technology is widely used. This technology was originally invented by the Battelle Institute. Traditional methods usually have problems such as low efficiency, excessive heat input, and large welding deformation. The narrow gap welding technology effectively improves welding efficiency, reduces heat input, and significantly reduces welding deformation, making it more suitable for the high-quality welding needs of thick-walled metal materials.

[0003] In recent years, laser has gradually become a high-quality heat source in narrow gap welding process due to its superior characteristics of high energy density and strong directivity, and has attracted widespread attention. In particular, narrow gap laser wire welding technology performs well in the welding of components that require high processing and assembly precision. This technology can not only accurately meet the demanding welding application requirements, but also realize metallurgical regulation of the weld by filling the welding wire, effectively refining the microstructure grain. Narrow gap laser wire welding technology has become an important choice in the field of thick-walled metal material welding due to its significant advantages in improving welding quality and precision.

[0004] However, narrow gap laser wire welding technology has extremely high requirements for the strong coupling between the welding wire and the laser. In order to achieve this coupling, the welding wire position and laser focus, wire feeding speed and laser power must be precisely matched. In the narrow gap groove, the position of the welding wire also needs to be maintained with extremely high precision. Any slight deviation may cause the welding wire to collide with the side wall of the narrow gap, making it impossible for the welding wire to effectively couple with the laser. This mismatch will not only cause the workpiece to be scrapped, but may also cause defects in the weld, affecting the welding quality. Therefore, reducing the strong coupling between the welding wire and the laser is the key to further improving the stability and efficiency of narrow gap welding. Summary of the invention

[0005] The purpose of the present invention is to solve the problem of strong coupling between welding wire and laser in narrow gap laser welding process in view of the above-mentioned deficiencies in the prior art, and to provide a narrow gap welding device and method based on molten droplet coaxial composite ring laser, in which an induction heating heat source is additionally added to melt the welding wire, so that the role of the laser is only to produce a suitable molten pool, so as to achieve high-quality and high-quality welding of narrow gap workpieces.

[0006] The object of the present invention is achieved in that:

[0007] The novel molten droplet + coaxial ring laser narrow gap welding device includes a welding wire melting system, which is used to heat and melt the metal welding wire to generate a metal molten droplet jet, including an induction heating coil, which wraps a melting crucible, a ceramic filter is installed at the bottom of the melting crucible, and a molten metal control component is connected to the bottom of the melting crucible. The welding wire melting system is surrounded by an annular beam system, and the annular beam is used to generate a molten pool. After the molten metal passes through the molten metal control component, it drips vertically into the narrow gap workpiece molten pool in the form of a jet, and then the molten pool solidifies to form a narrow gap weld.

[0008] The upper part of the welding wire melting system is connected with a wire feeding system, which includes a wire feeder. The wire feeder feeds the welding wire into a welding wire straightener, which includes a bracket and a roller. After being straightened by the welding wire straightener, the welding wire is fed into the welding wire melting system to be melted into molten metal.

[0009] A water cooling kit is designed around the welding wire melting system, and the water cooling kit includes a cooling water inlet, a water cooling chamber, a cooling water outlet, and a cooling system.

[0010] Cooling water enters from the cooling water inlet, passes through the water cooling chamber, takes away the heat of the welding wire melting system, and returns to the cooling system through the cooling water outlet; the water cooling kit is connected to the temperature sensor, and the temperature sensor collects the temperature information of the welding wire melting system. Through the action of the water cooling kit, the temperature of the device is maintained in a safe range.

[0011] The molten metal control component includes an electric valve, a nozzle channel, and an electronically adjustable nozzle. An electric valve is installed on the upper part of the nozzle channel to control the molten metal to flow from the smelting crucible into the nozzle channel. A heating jacket is designed on the outside of the nozzle channel to keep the temperature of the molten metal stable when passing through the channel. An electronically adjustable nozzle is installed at the tail of the nozzle channel. The electronically adjustable nozzle is connected to the control system. The control system receives the narrow gap size information obtained by the laser profile scanner and feeds it back to the electronically adjustable nozzle to adjust the droplet size and flow rate according to the gap size.

[0012] The annular beam system comprises a laser, an optical fiber, a single-sided convex lens and an annular beam; the laser outputs a semi-annular beam through the optical fiber, and two semi-annular beams are combined into a complete annular beam after being reflected by the single-sided convex lens.

[0013] The wire feeding system, welding wire melting system and molten metal control assembly are all located in the same closed space, and the wire feeding machine housing is connected to the gas pressure system.

[0014] The gas pressure system includes a gas cylinder, a pressure controller, and a pressure sensor. The gas pressure system drives the molten metal to flow vertically into the molten pool by increasing the gas pressure in the confined space. The gas introduced is an inert gas to prevent oxidation of the molten metal.

[0015] A pressure relief valve is installed on the wire feeder housing.

[0016] The narrow gap workpiece is fixed on a CNC machine tool. When in working state, the device remains fixed and the workpiece moves along a predetermined trajectory.

[0017] A novel molten droplet + coaxial ring laser narrow gap welding method, using the above device, includes the following steps:

[0018] Step 1: Calculate the welding path and the amount of wire required to be fed based on the narrow gap size.

[0019] Step 2: Determine the appropriate annular beam laser power, welding speed, droplet size, and jet state based on the narrow gap size and material.

[0020] Step 3: Feed part of the welding wire into the melting crucible, close the electric valve, turn on the induction coil, cooling system, and temperature sensor, set the heating target temperature and heating rate, and heat the welding wire.

[0021] Step 4: After heating to the target temperature and the welding wire is melted into molten liquid, turn on the gas cylinder, pressure controller, and pressure sensor, adjust the gas pressure to a reasonable range, open the electric valve and the electric adjustable nozzle, and adjust to the appropriate molten droplet jet state.

[0022] Step 5: Place the workpiece in the designated position, turn on the laser, start the CNC machine, and weld the narrow gap workpiece.

[0023] Step 6: During the welding process, the laser profile scanner monitors the gap size. For the common narrow gap groove that is wide at the top and narrow at the bottom, as the number of narrow gap layers increases, the gap size increases. The control system controls the electric adjustable nozzle to increase the droplet size and reduce the frequency.

[0024] Step 7: Welding is completed and the desired narrow gap weld is obtained.

[0025] The present invention has the following beneficial effects:

[0026] The present invention melts the welding wire to generate molten droplets by induction heat source, and successfully solves the problem of strong coupling between welding wire and laser compared with the traditional laser wire filling narrow gap welding method. This improvement significantly enhances the stability and quality of narrow gap welding. Since the main role of the laser in this process is only to generate a suitable molten pool, and high power is not required to melt the welding wire, this method can significantly reduce the heat input in the welding process, thereby reducing deformation and defects in narrow gap welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of a new type of molten droplet + coaxial ring laser narrow gap welding device;

[0028] Figure 2 It is a schematic diagram of the welding process of a new type of molten droplet + coaxial ring laser narrow gap welding device;

[0029] Among them, 1: welding wire melting system; 1-1: melting crucible; 1-2: induction heating coil; 1-3: ceramic filter; 2: metal melt control component; 2-1: electric valve; 2-2: heating jacket; 2-3: nozzle channel; 2-4: electronic adjustable nozzle; 3: wire feeding system; 3-1: wire feeder; 3-2: welding wire; 3-3: welding wire straightener; 3-3-1: bracket; 3-3-2: roller; 4: water cooling kit; 4-1: cooling water inlet; 4-2: water cooling chamber; 4-3: cooling system; 4 -4: cooling water outlet; 5: annular beam system; 5-1: laser; 5-2: optical fiber; 5-3: single-sided convex lens; 5-4: annular beam; 6: gas pressure system; 6-1: gas cylinder; 6-2: pressure controller; 6-3: pressure sensor; 7: temperature sensor; 8: laser profile scanner; 9: molten drop; 10: molten pool; 11-narrow gap groove; 12: narrow gap workpiece; 13: control system; 14: pressure relief valve; 15: narrow gap weld; 16: molten metal; 17: CNC machine tool; DETAILED DESCRIPTION

[0030] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0031] In the description of this embodiment, terms such as "up", "down", "left", and "right" and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation.

[0032] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0033] The novel molten droplet + coaxial ring laser narrow gap welding device includes a welding wire melting system 1, the welding wire melting system 1 is used to heat and melt the metal welding wire 3-2 to generate a metal molten droplet jet 9, including an induction heating coil 1-2, the induction heating coil 1-2 wraps a melting crucible 1-1, a ceramic filter 1-3 is installed at the lower part of the melting crucible 1-1, and a metal melt control component 2 is connected to the bottom of the melting crucible 1-1. The welding wire melting system 1 is surrounded by an annular beam system 5, and the annular beam 5-4 is used to generate a molten pool 10. After the molten liquid passes through the metal melt control component 2, it drips vertically into the narrow gap workpiece molten pool 10 in the form of a jet, and then the molten pool solidifies to form a narrow gap weld 15.

[0034] The upper part of the welding wire melting system 1 is connected to a wire feeding system 3, which includes a wire feeder 3-1. The wire feeder 3-1 feeds the welding wire 3-2 into a welding wire straightener 3-3. The welding wire straightener 3-3 includes a bracket 3-3-1 and a roller 3-3-2. After being straightened by the welding wire straightener 3-3, the welding wire 3-2 is fed into the welding wire melting system 1 to be melted into molten metal 16.

[0035] A water cooling kit 4 is designed around the welding wire melting system 1. The water cooling kit 4 includes a cooling water inlet 4-1, a water cooling chamber 4-2, a cooling water outlet 4-4, and a cooling system 4-3.

[0036] The cooling water enters from the cooling water inlet 4-1, passes through the water cooling chamber 4-2, takes away the heat of the welding wire melting system 1, and returns to the cooling system 4-3 through the cooling water outlet 4-4; the water cooling kit 4 is connected to the temperature sensor 7, and the temperature sensor 7 collects the temperature information of the welding wire melting system 1. Through the action of the water cooling kit 4, the temperature of the device is maintained in a safe range.

[0037] The molten metal control component 2 includes an electric valve 2-1, a nozzle channel 2-3, and an electronically adjustable nozzle 2-4. The electric valve 2-1 is installed on the upper part of the nozzle channel 2-3 to control the molten metal 16 to flow from the smelting crucible 1-1 into the nozzle channel 2-3. The nozzle channel 2-3 is designed with a heating jacket 2-2 on the outside to keep the temperature of the molten metal 16 stable when passing through the channel 2-3. The tail of the nozzle channel 2-3 is installed with an electronically adjustable nozzle 2-4, and the electronically adjustable nozzle 2-4 is connected to the control system 13. The control system 13 receives the narrow gap size information obtained by the laser profile scanner 8, and feeds it back to the electronically adjustable nozzle 2-4, so as to adjust the size and flow rate of the molten droplet 9 according to the gap size.

[0038] The annular beam system 5 includes a laser 5-1, an optical fiber 5-2, a single-sided convex lens 5-3, and an annular beam 5-4; the laser outputs a semi-annular beam through the optical fiber 5-2, and the two semi-annular beams are reflected by the single-sided convex lens 5-3 and combined into a complete annular beam 5-4.

[0039] The wire feeding system 3 , the welding wire melting system 1 , and the molten metal control component 2 are all in the same enclosed space, and the outer shell of the wire feeder 3 - 1 is connected to the gas pressure system 6 .

[0040] The gas pressure system 6 includes a gas cylinder 6-1, a pressure controller 6-2, and a pressure sensor 6-3. The gas pressure system 6 drives the molten metal 16 to flow vertically into the molten pool 10 by increasing the gas pressure in the enclosed space. The gas introduced is an inert gas to prevent the molten metal 16 from being oxidized.

[0041] A pressure relief valve 14 is installed on the casing of the wire feeder 3 - 1 .

[0042] The narrow gap workpiece 12 is fixed on a CNC machine tool 17. When in working state, the device remains fixed and the workpiece moves along a predetermined trajectory.

[0043] A novel molten droplet + coaxial ring laser narrow gap welding method, using the above device, includes the following steps:

[0044] Step 1: Calculate the welding path and the amount of welding wire 3-2 required to be fed according to the size of the narrow gap groove 11.

[0045] Step 2: Determine the appropriate annular beam laser power, welding speed, droplet size and jet state according to the size and material of the narrow gap groove 11.

[0046] Step 3: Feed part of the welding wire 3-2 into the melting crucible 1-1, close the electric valve 2-1, turn on the induction coil 1-2, the water cooling kit 4, and the temperature sensor 7, set the heating target temperature and the heating rate, and heat the welding wire.

[0047] Step 4: After being heated to the target temperature and the welding wire 3-2 is melted into the molten liquid 16, the gas cylinder 6-1, the pressure controller 6-2, and the pressure sensor 6-3 are turned on, the gas pressure is adjusted to a reasonable range, and the electric valve 2-1 and the electric adjustable nozzle 2-4 are opened to adjust to a suitable molten droplet jet state.

[0048] Step 5: Place the workpiece 12 in the designated position, turn on the laser 5 - 1 , start the CNC machine tool 17 , and weld the narrow gap workpiece 12 .

[0049] Step 6: During the welding process, the laser profile scanner 8 monitors the gap size. For the common narrow gap groove 11 that is wide at the top and narrow at the bottom, as the number of narrow gap layers increases, the gap size increases. The control system 13 controls the electric adjustable nozzle 2-4 to increase the size of the molten droplet 9 and reduce the frequency.

[0050] Step 7: Welding is completed and the desired narrow gap weld 15 is obtained.

[0051] The present invention is further described below by a specific embodiment.

[0052] The above device is used to weld an aluminum alloy thick plate with a thickness of 70 mm. The size of the groove 11 is a bottom width of 13 mm, a groove angle of 1.5°, and the shielding gas is argon.

[0053] The welding path and the amount of aluminum alloy welding wire 3-2 required to be fed are calculated based on the size of the narrow gap groove 11.

[0054] Furthermore, the annular beam laser power is set to 3 kW, the welding speed is 2 m / min, the droplet size is 1 mm, and the frequency is 50 Hz.

[0055] Feed part of the welding wire 3-2 into the melting crucible 1-1, close the electric valve 2-1, turn on the induction coil 1-2, the water cooling kit 4, and the temperature sensor 7, set the heating target temperature to 900°C, and the heating rate to 30°C / min to heat the aluminum alloy welding wire.

[0056] Furthermore, after being heated to the target temperature and the welding wire 3-2 is melted into the molten liquid 16, the gas cylinder 6-1, the pressure controller 6-2 and the pressure sensor 6-3 are opened, the gas pressure is adjusted to a reasonable range, the electric valve 2-1 and the electric adjustable nozzle 2-4 are opened, and adjusted to a suitable molten droplet jet state.

[0057] Furthermore, the workpiece 12 is placed in a designated position, the laser 5 - 1 is turned on, the CNC machine tool 17 is started, and the narrow gap workpiece 12 is welded.

[0058] Furthermore, during the welding process, the laser profile scanner 8 monitors the gap size. For the common narrow gap groove 11 that is wide at the top and narrow at the bottom, as the number of narrow gap layers increases, the gap size increases, and the control system 13 controls the electric adjustable nozzle 2-4 to increase the size of the molten droplet 9 and reduce the frequency.

[0059] Further, the welding is completed and the desired narrow gap weld 15 is obtained.

[0060] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A narrow gap welding device and method based on droplet coaxial composite ring laser, characterized in that: The welding wire melting system includes a welding wire melting system for heating and melting the metal welding wire to generate a metal molten droplet jet, including an induction heating coil, the induction heating coil wraps a smelting crucible, a ceramic filter is installed at the bottom of the smelting crucible, and a molten metal control component is connected to the bottom of the smelting crucible. The welding wire melting system is surrounded by an annular beam system, and the annular beam is used to generate a molten pool. After the molten metal passes through the molten metal control component, it vertically drips into the narrow gap workpiece molten pool in the form of a jet, and then the molten pool solidifies to form a narrow gap weld; The upper part of the welding wire melting system is connected with a wire feeding system, which includes a wire feeder. The wire feeder feeds the welding wire into a welding wire straightener, which includes a bracket and a roller. After being straightened by the welding wire straightener, the welding wire is fed into the welding wire melting system to be melted into molten metal. A water cooling kit is designed around the welding wire melting system, and the water cooling kit includes a cooling water inlet, a water cooling chamber, a cooling water outlet, and a cooling system; the cooling water enters from the cooling water inlet and passes through the water cooling chamber to take away the heat of the welding wire melting system, and returns to the cooling system through the cooling water outlet; the water cooling kit is connected to a temperature sensor, and the temperature sensor collects the temperature information of the welding wire melting system. Through the action of the water cooling kit, the temperature of the device is maintained within a safe range; The molten metal control component includes an electric valve, a nozzle channel, and an electronically adjustable nozzle. An electric valve is installed on the upper part of the nozzle channel to control the molten metal to flow from the smelting crucible into the nozzle channel. A heating jacket is designed on the outside of the nozzle channel to keep the temperature of the molten metal stable when passing through the channel. An electronically adjustable nozzle is installed at the tail of the nozzle channel. The electronically adjustable nozzle is connected to the control system. The control system receives the narrow gap size information obtained by the laser profile scanner and feeds it back to the electronically adjustable nozzle to adjust the droplet size and flow rate according to the gap size.

2. According to claim 1, a narrow gap welding device and method based on droplet coaxial composite ring laser is characterized in that: The annular beam system comprises a laser, an optical fiber, a single-sided convex lens and an annular beam; the laser outputs a semi-annular beam through the optical fiber, and two semi-annular beams are combined into a complete annular beam after being reflected by the single-sided convex lens.

3. According to claim 1, a narrow gap welding device and method based on droplet coaxial composite ring laser is characterized in that: The wire feeding system, welding wire melting system, and molten metal control assembly are all in the same enclosed space. The wire feeder housing is connected to a gas pressure system. The gas pressure system includes a gas cylinder, a pressure controller, and a pressure sensor. The gas pressure system drives the molten metal to flow vertically into the molten pool by increasing the air pressure in the enclosed space. The gas introduced is an inert gas to prevent oxidation of the molten metal. A pressure relief valve is installed in the wire feeder housing.

4. According to claim 1, a narrow gap welding device and method based on droplet coaxial composite ring laser is characterized in that: The narrow gap workpiece is fixed on a CNC machine tool. When in working state, the device remains fixed and the workpiece moves along a predetermined trajectory.

5. A narrow gap welding device and method based on droplet coaxial composite ring laser, characterized in that: The following steps are involved: Step 1: Calculate the welding path and the amount of welding wire required to be fed according to the narrow gap size; Step 2: Determine the appropriate annular beam laser power, welding speed, droplet size and jet state according to the narrow gap size and material; Step 3: Feed part of the welding wire into the melting crucible, close the electric valve, turn on the induction coil, cooling system, and temperature sensor, set the heating target temperature and heating rate, and heat the welding wire; Step 4: After the welding wire is heated to the target temperature and melted into liquid, turn on the gas cylinder, pressure controller, and pressure sensor, adjust the gas pressure to a reasonable range, open the electric valve and the electric adjustable nozzle, and adjust to a suitable droplet jet state; Step 5: Place the workpiece in the designated position, turn on the laser, start the CNC machine tool, and weld the narrow gap workpiece; Step 6: During the welding process, the laser profile scanner monitors the gap size. For the common narrow gap groove with wide top and narrow bottom, as the number of narrow gap layers increases, the gap size increases. The control system controls the electric adjustable nozzle to increase the droplet size and reduce the frequency. Step 7: Welding is completed and the desired narrow gap weld is obtained.

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