A narrow gap welding apparatus and method based on coaxial composite ring laser

Abstract

The present application provides a kind of narrow gap welding device and method based on coaxial composite annular laser of droplet, it is suitable for high-precision narrow gap welding.The device includes welding wire melting system, annular beam system, wire feeding system, water cooling kit, metal melt control assembly and gas pressure system.Welding wire melting system heats metal welding wire by induction heating coil, generates droplet jet, and annular beam system generates molten pool.Droplets are vertically dropped into the molten pool of narrow gap workpiece in the form of jet through the metal melt control assembly, forming high-quality welds.The control system monitors the gap size in real time through laser profile scanner and adjusts the electronic adjustable nozzle to control the size and flow of droplets.The present application successfully solves the strong coupling problem between welding wire and laser by melting welding wire with induction heat source, and significantly reduces the heat input in the welding process, thereby reducing deformation and defects in narrow gap welding.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of narrow gap welding, in particular to a narrow gap welding device and method based on coaxial composite annular laser droplet. BACKGROUND

[0002] With the continuous development of modern engineering machinery and national defense equipment towards large-scale, the application of thick-walled metal materials becomes more and more common. Especially in key manufacturing fields such as nuclear power equipment, tank armor, ocean engineering and shipbuilding, thick-walled metal materials have become an indispensable part. In the process of welding thick-walled metal materials, narrow gap welding technology is widely used. This technology was originally invented by Battelle Institute. The traditional method usually has the problems of low efficiency, high heat input and large welding deformation, while the narrow gap welding technology effectively improves the welding efficiency, reduces the heat input and significantly reduces the welding deformation, so it is more suitable for the high-quality welding requirements of thick-walled metal materials.

[0003] Laser has become a high-quality heat source in narrow gap welding process in recent years due to its superior characteristics of high energy density and strong directivity, and has attracted widespread attention. Especially the narrow gap laser wire filling welding technology performs well in the welding of components with high machining and assembly precision. This technology not only accurately meets the demanding welding application requirements, but also realizes the metallurgical control of the weld through the filling of welding wire, effectively refining the grain structure. Narrow gap laser wire filling 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, the narrow gap laser wire filling welding technology has very high requirements for the strong coupling of welding wire and laser. In order to achieve this coupling, the position of the welding wire and the laser focus, the wire feeding speed and the laser power must be precisely matched. In the narrow gap groove, the position of the welding wire also needs to be kept at a very high precision. Any slight deviation may cause the welding wire to collide with the sidewall of the narrow gap, and then the welding wire cannot be effectively coupled with the laser. This mismatch not only causes the workpiece to be scrapped, but also may produce defects in the weld, affecting the welding quality. Therefore, reducing the strong coupling of welding wire and laser is the key to further improving the stability and efficiency of narrow gap welding. SUMMARY

[0005] The purpose of the present application is to solve the problem of strong coupling of welding wire and laser in the process of narrow gap laser welding, and to provide a narrow gap welding device and method based on coaxial composite annular laser droplet. The additional induction heating heat source melts the welding wire, so that the action of the laser is only to generate a suitable molten pool, to realize high-quality welding of narrow gap workpieces.

[0006] The purpose of the present application is achieved as follows:

[0007] The new droplet + coaxial ring laser narrow gap welding device includes a welding wire melting system for heating and melting the metal welding wire to generate a metal droplet jet, an induction heating coil wrapped around a smelting crucible, a ceramic filter installed at the lower part of the smelting crucible, a metal melt control assembly connected to the bottom of the smelting crucible, and a ring beam system surrounding the welding wire melting system, the ring beam being used to generate a molten pool, the molten metal being vertically dropped into the molten pool of the narrow gap workpiece in the form of a jet after passing through the metal melt control assembly, and then the molten pool solidifies to form a narrow gap weld.

[0008] The upper part of the welding wire melting system is connected to a wire feeding system, the wire feeding system including a wire feeder feeding the welding wire into a wire straightener including a bracket and a roller, the welding wire being fed into the welding wire melting system after being straightened by the wire straightener to be melted into a metal melt.

[0009] A water cooling jacket is designed around the welding wire melting system, the water cooling jacket including a cooling water inlet, a water cooling cavity, a cooling water outlet, and a cooling system.

[0010] The cooling water enters the water cooling cavity through the cooling water inlet to take away the heat of the welding wire melting system, and is returned to the cooling system through the cooling water outlet; the water cooling jacket is connected to a temperature sensor that collects temperature information of the welding wire melting system, and the temperature of the device is maintained within a safe range through the action of the water cooling jacket.

[0011] The metal melt control assembly includes an electric valve, a nozzle channel, and an electronically adjustable nozzle, the electric valve being installed at the upper part of the nozzle channel to control the flow of the melt from the smelting crucible into the nozzle channel, a heating jacket being designed outside the nozzle channel to keep the temperature stable when the melt passes through the channel, and the electronically adjustable nozzle being installed at the tail of the nozzle channel and connected to a control system, the control system receiving the information of the narrow gap size from a laser profile scanner and feeding it back to the electronically adjustable nozzle to adjust the size and flow of the droplet according to the size of the gap.

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

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

[0014] The gas pressure system includes a gas cylinder, a pressure controller, and a pressure sensor, and drives the metal melt to flow vertically into the molten pool by increasing the gas pressure in the closed space, the gas being inert gas to avoid oxidation of the metal melt.

[0015] The wire feeder housing is provided with a pressure relief valve.

[0016] The narrow gap workpiece is fixed on the numerical control machine tool, and the device is kept fixed when in working condition, and the workpiece moves along the predetermined track.

[0017] A novel narrow gap welding method of droplet + coaxial annular laser, using the above device, comprises the following steps:

[0018] Step 1: calculate the welding path and the amount of welding wire required according to the size of the narrow gap.

[0019] Step 2: determine the appropriate annular laser beam power, welding speed, droplet size and jet state according to the size of the narrow gap and the material.

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

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

[0022] Step 5: place the workpiece in the designated position, turn on the laser, start the numerical control machine tool, and weld the narrow gap workpiece.

[0023] Step 6: during the welding process, the laser contour scanner monitors the gap size, for the common narrow gap groove with wide upper and narrow lower, 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: after welding, the required narrow gap weld is obtained.

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

[0026] The present application melts the welding wire by an induction heat source to generate droplets, compared with the traditional laser filler wire narrow gap welding method, the strong coupling problem between the welding wire and the laser is successfully solved. This improvement significantly enhances the stability and quality of narrow gap welding. Since the main role of laser in this process is only to generate a suitable molten pool, without the need for high power to melt the welding wire, this method can significantly reduce the heat input in the welding process, thereby reducing the deformation and defects in the narrow gap welding. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a schematic view of the novel narrow gap welding device of droplet + coaxial annular laser;

[0028] Figure 2 A schematic diagram of a new type of narrow gap welding device with droplet + coaxial ring laser welding process;

[0029] 1: welding wire melting system; 1-1: smelting crucible; 1-2: induction heating coil; 1-3: ceramic filter; 2: metal liquid control assembly; 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 set; 4-1: cooling water inlet; 4-2: water cooling cavity; 4-3: cooling system; 4-4: cooling water outlet; 5: ring beam system; 5-1: laser; 5-2: optical fiber; 5-3: single convex lens; 5-4: ring 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: droplet; 10: molten pool; 11: narrow gap groove; 12: narrow gap workpiece; 13: control system; 14: pressure relief valve; 15: narrow gap weld; 16: metal liquid; 17: numerical control machine tool; DETAILED DESCRIPTION

[0030] To make the technical problems solved by the present application, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the embodiments of the present application will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0031] In the description of the present embodiment, the terms "upper", "lower", "left", "right" and the like orientation or position relationship are based on the orientation or position relationship shown in the drawings, which is only for the convenience of description and simplification of operation, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation.

[0032] The technical solutions of the present application will be further described below with reference to the drawings and through specific embodiments.

[0033] The new droplet + coaxial ring laser narrow gap welding device includes a welding wire melting system 1 for heating and melting the metal welding wire 3-2 to generate a metal droplet jet 9, an induction heating coil 1-2 wrapped around a smelting crucible 1-1, a ceramic filter 1-3 installed at the lower part of the smelting crucible 1-1, a metal melt control assembly 2 connected to the bottom of the smelting crucible 1-1, a ring beam system 5 surrounding the welding wire melting system 1, a ring beam 5-4 for generating a molten pool 10, and a metal melt control assembly 2 for vertically dropping the molten pool into the narrow gap workpiece molten pool 10 in the form of a jet after passing through the metal melt control assembly 2, and then the molten pool solidifies to form a narrow gap weld 15.

[0034] The welding wire melting system 1 is connected to an upper part of a wire feeding system 3, which includes a wire feeder 3-1 feeding the welding wire 3-2 into a wire straightener 3-3 including a support 3-3-1 and a roller 3-3-2, and the welding wire 3-2 is sent into the welding wire melting system 1 after being straightened by the wire straightener 3-3 to be melted into a metal melt 16.

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

[0036] The cooling water enters the water cooling cavity 4-2 through the cooling water inlet 4-1 to take 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 assembly 4 is connected to a temperature sensor 7 collecting temperature information of the welding wire melting system 1, and the temperature of the device is maintained within a safe range through the action of the water cooling assembly 4.

[0037] The metal melt control assembly 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 at the upper part of the nozzle channel 2-3 to control the flow of the melt 16 from the smelting crucible 1-1 into the nozzle channel 2-3, a heating jacket 2-2 is designed outside the nozzle channel 2-3 to keep the temperature of the melt 16 stable when passing through the channel 2-3, and the electronically adjustable nozzle 2-4 is installed at the tail of the nozzle channel 2-3 and connected to a control system 13, which receives the narrow gap size information from a laser profile scanner 8 and feeds back to the electronically adjustable nozzle 2-4 to adjust the size and flow of the droplet 9 according to the size of the gap.

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

[0039] The wire feeding system 3, the welding wire melting system 1 and the metal melt control assembly 2 are located in the same closed space, and the wire feeder 3-1 shell is connected with the gas pressure system 6.

[0040] The gas pressure system 6 comprises a gas cylinder 6-1, a pressure controller 6-2 and a pressure sensor 6-3, and the gas pressure system 6 drives the metal melt 16 to flow vertically into the molten pool 10 by increasing the gas pressure in the closed space, and the gas is inert gas, which avoids the oxidation of the metal melt 16.

[0041] The wire feeder 3-1 shell is provided with a pressure relief valve 14.

[0042] The narrow-gap workpiece 12 is fixed on the numerical control machine tool 17, and in the working state, the device is fixed, and the workpiece moves along the predetermined track.

[0043] A novel narrow-gap welding method of droplet + coaxial annular laser, which adopts the device, comprises the following steps.

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

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

[0046] Step 3: part of the welding wire 3-2 is fed into the melting crucible 1-1, the electric valve 2-1 is closed, the induction coil 1-2, the water cooling assembly 4 and the temperature sensor 7 are opened, the target heating temperature and the heating rate are set, and the welding wire is heated.

[0047] Step 4: after the welding wire 3-2 is heated to the target temperature and melted into the melt 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 electrically adjustable nozzle 2-4 are opened, and the droplet jet state is adjusted to be appropriate.

[0048] Step 5: the workpiece 12 is placed in the specified position, the laser 5-1 is turned on, and the numerical control machine tool 17 is started to weld the narrow-gap workpiece 12.

[0049] Step 6: during the welding process, the gap size is monitored by the laser contour scanner 8, for the common narrow-gap groove 11 which 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 electrically adjustable nozzle 2-4 to increase the size of the droplet 9 and reduce the frequency.

[0050] Step 7: the welding is completed, and the required narrow-gap weld 15 is obtained.

[0051] The application is further illustrated by a specific embodiment below.

[0052] The thick aluminum alloy plate with a thickness of 70 mm is welded by using the device, the groove 11 has a bottom width of 13 mm and a groove angle of 1.5°, and the protective gas is argon.

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

[0054] Further, 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] The feeding part of the welding wire 3-2 enters the melting crucible 1-1, the electric valve 2-1 is closed, the induction coil 1-2, the water cooling assembly 4 and the temperature sensor 7 are opened, the heating target temperature is set to 900 ℃, the heating rate is 30 ℃ / min, and the aluminum alloy welding wire is heated.

[0056] Further, after being heated to the target temperature, 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 electrically adjustable nozzle 2-4 are opened, and the molten droplet jet state is adjusted.

[0057] Further, the workpiece 12 is placed in the specified position, the laser 5-1 is opened, and the numerical control machine tool 17 is started to weld the narrow gap workpiece 12.

[0058] Further, during the welding process, the gap size is monitored by the laser contour scanner 8, for the common narrow gap groove 11 which is wide at the top and narrow at the bottom, as the number of narrow gap layers increases, the gap size increases, the electrically adjustable nozzle 2-4 is controlled by the control system 13 to increase the size of the molten droplet 9 and reduce the frequency.

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

[0060] Obviously, the above embodiment of the application is only an example for clearly illustrating the application, and is not a limitation on the embodiments of the application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments are not required to be exhausted. Any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the claims of the application.

Claims

1. A narrow gap welding apparatus based on coaxial composite ring laser of molten droplet, characterized in that, The welding wire melting system is used for heating and melting the metal welding wire to generate a metal droplet jet, and includes an induction heating coil wrapped around a smelting crucible, a ceramic filter mounted at a lower portion of the smelting crucible, and a metal melt control assembly connected to a bottom of the smelting crucible; the welding wire melting system is surrounded by a ring-shaped light beam system, and the ring-shaped light beam is used to generate a molten pool; after passing through the metal melt control assembly, the metal melt is vertically dropped into the molten pool of the narrow-gap workpiece in the form of a jet, and then the molten pool solidifies to form a narrow-gap weld joint; The welding wire melting system is connected to an upper portion of a wire feeding system, and the wire feeding system includes a wire feeder that feeds the welding wire into a wire straightener including a support and a roller; after being straightened by the wire straightener, the welding wire is fed into the welding wire melting system to be melted into a metal melt; A water cooling assembly is designed around the welding wire melting system, and the water cooling assembly includes a cooling water inlet, a water cooling cavity, a cooling water outlet, and a cooling system; cooling water enters the water cooling cavity through the cooling water inlet, carries away the heat of the welding wire melting system, and is returned to the cooling system through the cooling water outlet; the water cooling assembly is connected to a temperature sensor that collects temperature information of the welding wire melting system; and the temperature of the device is maintained within a safe range through the action of the water cooling assembly; The metal melt control assembly includes an electric valve, a nozzle channel, and an electronically adjustable nozzle; the electric valve is mounted at an upper portion of the nozzle channel to control the flow of the metal melt from the smelting crucible into the nozzle channel; a heating jacket is designed outside the nozzle channel to keep the temperature of the metal melt stable when the metal melt passes through the channel; and the electronically adjustable nozzle is mounted at a tail portion of the nozzle channel and is connected to a control system; the control system receives the narrow-gap size information obtained by a laser profile scanner, feeds back the information to the electronically adjustable nozzle, and adjusts the size and flow of the droplet according to the size of the gap.

2. A narrow gap welding apparatus based on coaxial composite ring laser with droplet according to claim 1, characterized in that: The ring-shaped light beam system includes a laser, an optical fiber, a single convex lens, and a ring-shaped light beam; the laser outputs a half-ring-shaped light beam through the optical fiber, and the two half-ring-shaped light beams are combined into a complete ring-shaped light beam after being reflected by the single convex lens.

3. A narrow gap welding apparatus based on coaxial composite ring laser with droplet according to claim 1, characterized in that: The wire feeding system, the welding wire melting system, and the metal melt control assembly are located in the same closed space; a gas pressure system including a gas cylinder, a pressure controller, and a pressure sensor is connected to a housing of the wire feeder; the gas pressure system drives the metal melt to flow vertically into the molten pool by increasing the air pressure in the closed space; the gas is inert gas to avoid oxidation of the metal melt; and the housing of the wire feeder is provided with a pressure relief valve.

4. A narrow gap welding apparatus based on coaxial composite ring laser with droplet according to claim 1, characterized in that, The narrow-gap workpiece is fixed on a numerical control machine tool, and the device is kept fixed when in operation; and the workpiece moves along a predetermined track.

5. A narrow gap welding method based on coaxial composite annular laser droplet, according to claim 3, characterized in that, The method includes the following steps: Step 1: calculating the welding path and the amount of welding wire required according to the size of the narrow gap; Step 2: determining appropriate ring-shaped light beam laser power, welding speed, droplet size, and jet state according to the size of the narrow gap and the material; Step 3: feeding part of the welding wire into the smelting crucible, closing the electric valve, starting the induction coil, the cooling system, and the temperature sensor, setting the target heating temperature and the heating rate, and heating the welding wire. Step 4: After the welding wire is melted into a molten liquid by heating to the target temperature, open the gas cylinder, pressure controller, and pressure sensor, adjust the gas pressure to a reasonable range, open the electric valve and electric adjustable nozzle, and adjust to the appropriate molten droplet jet state; Step 5: Place the workpiece in the designated position, turn on the laser, and start the numerical control machine tool to weld the narrow gap workpiece; Step 6: During the welding process, the laser contour scanner monitors the gap size. For the common narrow gap groove with a wide upper part and a narrow lower part, as the number of narrow gap layers increases, the gap size increases, the control system controls the electric adjustable nozzle to increase the size of the molten droplets and reduce the frequency; Step 7: After welding, the desired narrow gap weld is obtained.

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