A manual tungsten argon arc welding external control device and control method

Abstract

The present application belongs to the technical field of argon arc welding control, and particularly relates to a manual tungsten argon arc welding external control device and a control method. The control device and the control method are characterized by the welding circuit on-off module for controlling the on-off of the welding circuit, the argon on-off module for controlling the on-off of the argon, the delay closing module for controlling the on-off of the argon flow, the delay on module for controlling the on-off of the welding circuit, the DC-DC power module for supplying power to each component, the high-frequency coupler and the high-frequency arc starting module for realizing high-frequency arc starting, and the switch module for controlling the switch of the device. The control device can control the arc starting, argon and electricity required in the manual tungsten argon arc welding process, and can solve the problem that the welding machine position needs to be frequently moved in the manual tungsten argon arc welding with large distance and frequent change of the welding field. The ordinary direct current welding machine with the step-down output external characteristic can have the manual tungsten argon arc welding function, so as to improve the welding quality, safety, save argon, improve the utilization rate of the welding equipment and the like.

Description

Technical Field

[0001] This invention belongs to the field of argon arc welding control technology, and particularly relates to an external control device and control method for manual tungsten inert gas welding. Background Technology

[0002] Manual tungsten inert gas (TIG) welding is a type of manual gas-shielded welding. It involves using a tungsten alloy rod as the electrode and utilizing argon gas flowing from the nozzle of the welding torch to create a continuous, closed gas flow around the molten pool, protecting the tungsten electrode, welding wire, and the high-temperature weld pool from oxidation. Manual TIG welding offers advantages such as ease of operation, excellent weld pool protection, dense weld metal structure, aesthetically pleasing weld formation, slag-free welds, and high non-destructive testing pass rate. It is widely used in petrochemical, power, and other engineering projects.

[0003] Existing argon arc welding control principles, such as Figure 1 As shown, argon cylinder 1 is connected to the inlet of cross valve 3 of welding torch 2 through a pressure reducing valve, argon flow meter and argon pipe. Then, welding torch 2 is connected to the outlet of cross valve 3 through an argon pipe. The positive terminal of welding machine 4 is connected to the workpiece 5 to be welded, and the negative terminal of welding machine 4 is connected to welding torch 2 through a cable.

[0004] Existing TIG welding machines are limited by the length of their welding torch cables, making them suitable for welding workpieces close to the machine, with a typical operating radius not exceeding 10 meters. Excessive torch distance affects the stability of the welding arc and the effectiveness of argon gas protection, ultimately impacting weld quality. However, pipeline welding in engineering construction is characterized by long distances, high altitudes, dispersed work sites, and high mobility, resulting in relatively few welding operations near the welding machine. Furthermore, the welding machine's weight makes it difficult to move easily, so it is typically housed in a welding machine enclosure or shed. While the commonly used simple TIG welding torch (commonly known as a "handle") can be moved and used over a wider area, long-distance and high-altitude welding requires a long argon gas pipe and welding control cable to connect the torch to the welding machine.

[0005] As a result, the following technical problems exist:

[0006] 1. Since there is no argon gas or welding machine close-range control device, the argon gas and welding machine are switched on and off manually at the argon gas cylinder and welding machine. During the welding process, argon gas needs to be introduced before igniting the welding arc and the power needs to be cut off and the arc needs to be extinguished before stopping the welding. However, since the workpiece is far away from the argon gas cylinder and welding machine, the argon gas loss is relatively large.

[0007] 2. The long argon gas tube and control cable increase the weight of the welding torch during welding, resulting in high labor intensity and low welding accuracy for welders, and also increasing the failure rate of the welding machine and control system.

[0008] 3. There is always an open-circuit voltage of about 85V between the welding torch and the workpiece, which can easily cause electric shock when changing the tungsten electrode.

[0009] 4. The lack of a high-frequency arc initiation function during welding can easily lead to welding defects such as tungsten inclusion during arc initiation and shrinkage cavities at the arc termination point. Summary of the Invention

[0010] To address at least one technical problem existing in the prior art, this application provides an external control device and method for manual tungsten inert gas (TIG) welding, which realizes the control of arc ignition, argon gas, and electricity required for the manual TIG welding process. This solves the problem of frequent repositioning of the welding machine due to large distances and frequent changes in the welding field in manual TIG welding, enabling ordinary DC welding machines with steep output characteristics to have complete manual TIG welding functions, thereby improving the welding quality, welding process safety, argon gas conservation, and utilization rate of welding equipment in manual TIG welding.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] An external control device for manual tungsten inert gas welding includes:

[0013] A welding circuit switching module is used to control the on / off state of the welding circuit and includes a negative input interface, a relay and a negative output interface connected in series.

[0014] Argon gas on / off module: used to control the on / off of argon gas between argon cylinder and welding torch, and includes an argon gas input interface, a solenoid valve, a hose and an argon gas output interface connected in series.

[0015] Delayed shutdown module: used to control the solenoid valve to open when it is powered on and to control the solenoid valve to close after a certain period of time when it is de-powered;

[0016] Delayed turn-on module: used to control the relay circuit to turn on after a certain period of time when it is powered on, and to control the relay circuit to turn off when it is de-powered;

[0017] DC-DC power supply module: used to step down the open-circuit voltage of the welding machine and supply power to the delayed turn-on module, delayed turn-off module, relay, and solenoid valve respectively;

[0018] High-frequency coupler: connected in series between the negative output interface and the output terminal of the relay;

[0019] High-frequency arc initiation module: It is powered by the open-circuit voltage of the welding machine and sends a high-frequency signal to the high-frequency coupler after being powered on. The high-frequency coupler outputs the obtained high-frequency signal to the negative output interface.

[0020] Switching module: Used to control the circuit connection and disconnection between the DC-DC power supply module and the delayed turn-on module, delayed turn-off module, relay, and solenoid valve respectively.

[0021] Preferably, it also includes a storage battery, and the switching module controls the circuit connection and disconnection between the storage battery and the delayed turn-on module, the delayed turn-off module, the relay, and the solenoid valve.

[0022] Preferably, it also includes a battery charging management module, which is powered by a DC-DC power supply module. The battery charging management module is used to charge the battery and provide operating voltage to the delayed turn-on module, the delayed turn-off module, the relay, and the solenoid valve.

[0023] Preferably, the positive input terminal of the high-frequency arc initiation module is electrically connected to the positive input terminal of the DC-DC power supply module, and the negative input terminal of the high-frequency arc initiation module is electrically connected to the negative output interface.

[0024] Preferably, a conductive clamp is electrically connected to the positive input terminal of the DC-DC power module, and the conductive clamp is used to electrically connect to the positive terminal of the welding machine.

[0025] Preferably, the switch module includes a micro switch and a micro switch socket connected in series with the micro switch, wherein the micro switch socket is electrically connected to the input terminals of the delayed turn-on module and the delayed turn-off module respectively;

[0026] The micro switch controls the circuit connection and disconnection between the DC-DC power module and the battery and the delayed turn-on module, the delayed turn-off module, the relay, and the solenoid valve, respectively.

[0027] Preferably, the positive input terminal of the DC-DC power module is electrically connected to the positive terminal of the welding machine, and the negative input terminal of the DC-DC power module is electrically connected to the negative input interface.

[0028] Preferably, it also includes a main unit housing, and the welding circuit switching module, argon gas switching module, delayed shutdown module, DC-DC power supply module, and switch module are disposed inside the main unit housing, and a handle is provided on the main unit housing.

[0029] A control method for an external control device for manual tungsten inert gas welding includes the following control process.

[0030] S1: Connect the argon gas input interface to the argon gas cylinder, connect the negative input interface to the negative terminal of the welding machine via a cable, connect the DC-DC power module to the positive terminal of the welding machine via a cable, connect the negative output interface to the welding torch via a cable, connect the argon gas output interface to the welding torch, and connect the positive terminal of the welding machine to the workpiece.

[0031] S2: Turn on the switch module, and the delayed shutdown module and delayed turn-on module are powered on.

[0032] After being powered on, the delayed shutdown module controls the solenoid valve to open, allowing argon gas to be output sequentially through the argon gas input interface, hose, and argon gas output interface to the welding torch. After being powered on for a certain period of time, the delayed conduction module controls the relay to engage, connecting the negative input interface, relay, negative output interface, and welding torch. When the relay engages, the high-frequency arc ignition module is powered on and sends a high-frequency signal to the high-frequency coupler for a certain period of time. The high-frequency coupler outputs the obtained high-frequency signal to the tungsten electrode of the welding torch through the negative output interface, thereby igniting the arc in the area already protected by argon gas.

[0033] S3: When welding is completed, the switch module is turned off. After the delayed conduction module loses power, it controls the relay to disconnect, thereby disconnecting the negative input interface, the relay, the negative output interface from the welding torch and extinguishing the arc. At the same time as the delayed conduction module loses power, the delayed shutdown module controls the solenoid valve to close after a certain delay, thereby disconnecting the passage from the argon cylinder to the welding torch.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] 1. This control device and method effectively connect the welding torch and welding machine while providing excellent automatic control over the gas, electricity, and arc ignition required for the welding process; 2. It automatically shuts off the argon gas when welding stops, eliminating the need for manual shut-off by the welder and preventing argon gas loss due to welder negligence in forgetting to close the argon gas valve or short-term work stoppage, thus saving argon gas; 3. It automatically disconnects the welding torch from the welding machine's open-circuit voltage, allowing welders to maintain and replace tungsten electrodes safely, avoiding electric shock accidents; 4. High-frequency arc ignition can, to some extent, prevent welding defects such as tungsten inclusions at the arc ignition point; 5. It can be connected to a DC welding machine, enabling DC welding machines without argon arc welding capabilities to also possess complete argon arc welding functions, thereby improving equipment utilization and avoiding redundant investment; 6. No additional power supply is required, facilitating flexible movement and safe operation at the welding site. Attached Figure Description

[0036] Figure 1 This is a schematic diagram illustrating the connection of a welding torch, argon cylinder, welding machine, and workpiece in the prior art.

[0037] Figure 2 This is a schematic diagram of the internal structure of the present invention.

[0038] Figure 3 This is a schematic diagram of the external structure of the present invention.

[0039] Figure 4 This is a schematic diagram showing the connection between the present invention and the welding torch, argon cylinder, welding machine, and weldment.

[0040] In the diagram: 1. Argon cylinder, 2. Welding torch, 3. Cross valve, 4. Welding machine, 5. Welded part, 6. Control device host, 61. Host housing, 62. Negative input interface, 63. Argon input interface, 64. Conductive clamp, 65. Negative output interface, 66. Micro switch socket, 67. Argon output interface, 68. Micro switch, 69. Handle, 610. Delayed turn-on module, 611. Delayed turn-off module, 612. High-frequency arc ignition module, 613. Battery charging management module, 614. DC-DC power supply module, 615. Relay, 616. Solenoid valve, 617. Hoses, 618. Battery, 619. High-frequency coupler. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0042] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Example:

[0043] See Figure 2 , 3 As shown, an external control device for manual tungsten inert gas (TIG) welding includes a main unit 6. The main unit 6 comprises a square housing 61 and, within the housing 61, a welding circuit switching module, an argon gas switching module, a delayed shutdown module 611, a delayed conduction module 610, a DC-DC power supply module 614, a high-frequency coupler 619, a high-frequency arc ignition module 612, a switch module, a battery 618, and a battery charging management module 613. To facilitate carrying and moving the main unit 6, a handle 69 is provided on the housing 61.

[0044] The argon gas on / off module controls the flow of argon gas between argon cylinder 1 and welding torch 2. It includes an argon gas input interface 63, a solenoid valve 616, a hose 617, and an argon gas output interface 67 connected in series. Both the argon gas input interface 63 and the argon gas output interface 67 adopt a pagoda-type connector and are fixed with bolts to the openings on the right and left panels of the main unit housing 61, respectively, to facilitate the connection of the gas pipe and ensure a firm, stable, and airtight seal.

[0045] The solenoid valve 616 is installed inside the main unit housing 61, with its input interface connected to the argon gas input interface 63 and its output interface connected to the hose 617. By controlling the opening and closing of the solenoid valve 616, the connection between the argon gas input interface 63 and the argon gas output interface 67 is controlled, thereby controlling the flow of argon gas between the argon gas cylinder 1 and the welding torch 2.

[0046] The welding circuit switching module is used to control the on / off state of the welding circuit and includes a negative input interface 62, a relay 615, and a negative output interface 65 connected in series. The negative input interface 62 and the negative output interface 65 are fixedly connected to the right and left panels of the main housing 61, respectively. The relay 615 is located inside the main housing 61, with its negative output terminal electrically connected to the negative input interface 62 and its positive output terminal electrically connected to the negative output interface 65. By controlling the on / off state of the relay 615, the on / off state of the circuit between the negative input interface 62 and the negative output interface 65 is controlled, thereby controlling the on / off state of the welding circuit between the welding machine 4, the welding torch 2, and the workpiece 5.

[0047] Furthermore, since high-frequency arc initiation can avoid welding defects such as tungsten inclusion at the arc initiation point to a certain extent, in this embodiment, the high-frequency coupler 619 is connected in series between the negative output interface 62 and the output terminal of the relay 615. Specifically, one end of the high-frequency coupler 619 is electrically connected to the positive terminal of the relay 615 output terminal, and the other end is electrically connected to the negative output interface 65. The high-frequency arc initiation module 612 is disposed inside the main housing 61 and is powered by the open-circuit voltage of the welding machine 4. After the high-frequency arc initiation module 612 is powered on, it sends a high-frequency signal to the high-frequency coupler 619, and the high-frequency coupler 619 outputs the obtained high-frequency signal to the negative output interface 65.

[0048] The main unit housing 61 also includes a delayed shutdown module 611, a delayed turn-on module 610, a DC-DC power supply module 614, and a switch module.

[0049] The delayed shutdown module 610 is used to immediately control the solenoid valve 616 to conduct when it is energized and to control the solenoid valve 616 to disconnect after a certain period of time when it is de-energized. The delayed turn-on module 610 is used to control the relay 615 circuit to conduct after a certain period of time when it is energized and to control the relay 615 circuit to disconnect when it is de-energized.

[0050] Therefore, through the above modules, when the delayed shutdown module 611 and the delayed turn-on module 610 are simultaneously energized, the delayed shutdown module 611 immediately controls the solenoid valve 616 to turn on, allowing argon gas from the argon cylinder 1 to enter the welding torch 2 via the argon gas input interface 63, the solenoid valve 616, the hose 617, and the argon gas output interface 67. Since the delayed turn-on module 610 needs to control the relay 615 circuit to turn on after a certain period of energization, argon gas can be introduced into the welding area before welding to prevent oxidation of the welding area. After welding is completed, the delayed turn-on module 610 immediately controls the relay 615 to turn off, thereby disconnecting the welding circuit. Since the delayed shutdown module 611 needs to control the solenoid valve 616 to turn off after a certain period of de-energization of the delayed turn-on module 610, argon gas can be continuously introduced for a certain period of time after welding is completed and the welding circuit is disconnected, further preventing oxidation of the welding area. This means that before welding, air is supplied to purge the air from the welding area, then the electric arc is ignited, and when welding is finished, the electric arc is extinguished in advance, and then the argon gas flow is turned off, so that the high-temperature weld pool continues to be protected by argon gas until the temperature of the weld pool drops and then the argon gas is turned off.

[0051] In order to supply power to the delayed turn-on module 610, the delayed turn-off module 611, the relay 615, and the solenoid valve 616, a DC-DC power module 614 is provided inside the main housing 61. The DC-DC power module 614 is used to step down the no-load voltage of the welding machine 4 and then supply power to the delayed turn-on module 610, the delayed turn-off module 611, the relay 615, and the solenoid valve 616 respectively.

[0052] To prevent welding process interruptions caused by the DC-DC module 614 having no voltage output during a brief short circuit in the arc, a storage battery 618 is also installed inside the main unit housing 61. A switching module controls the circuit connection and disconnection between the storage battery 618 and the delayed turn-on module 610, delayed turn-off module 611, relay 615, and solenoid valve 616. The storage battery 618 can be powered by a UPS and can be connected in parallel with the DC-DC power module 614, thereby avoiding power interruptions to the delayed turn-on module 610, delayed turn-off module 611, relay 615, and solenoid valve 616.

[0053] Furthermore, a battery charging management module 613 is also provided inside the main unit housing 61. The battery charging management module 613 is powered by the DC-DC power module 614. The battery charging management module 613 is used to charge the battery 618 and provide operating voltage to the delayed turn-on module 610, the delayed turn-off module 611, the relay 615, and the solenoid valve 616.

[0054] The switching module is used to control the on / off circuits between the DC-DC power module 614 and the delayed turn-on module 610, delayed turn-off module 611, relay 615, and solenoid valve 616, respectively. In this embodiment, the switching module includes a micro switch 68 and a micro switch socket 66 connected in series with the micro switch 68. The micro switch socket 66 is electrically connected to the input terminals of the delayed turn-on module 610 and the delayed turn-off module 611, respectively. The micro switch controls the on / off circuits between the DC-DC power module 614 and the battery 618 and the delayed turn-on module 610, delayed turn-off module 611, relay 615, and solenoid valve 616, respectively.

[0055] Specifically, a conductive clamp 64, located outside the main housing 61, is electrically connected via a cable to the positive input terminal of the DC-DC power module 614. The conductive clamp 64 is used to hold and electrically connect to the positive terminal of the welding machine 4, while the negative input terminal of the DC-DC power module 614 is electrically connected to the negative input interface 62. Therefore, when this control device is in use, if the conductive clamp 64 is held on the workpiece 5 or the positive terminal of the DC welding machine 4, the open-circuit voltage of the DC welding machine 4 is stepped down by the DC-DC module 614 and stabilized at 12V before supplying power to the battery charging management module 613. The battery charging management module 613 detects the charge level of the battery 618 and automatically turns on and off charging the battery 618. The 12V output voltage from the battery charging management module 613, together with the battery 618, provides operating voltage to the delayed turn-on module 610, the delayed turn-off module 611, the battery 618, the relay 615, and the solenoid valve 616.

[0056] The positive input terminal of the high-frequency arc ignition module 612 is electrically connected to the positive input terminal of the DC-DC power supply module 614, and the negative input terminal of the high-frequency arc ignition module 612 is electrically connected to the positive output terminal of the relay 615, and is also electrically connected to the negative output interface 65 through the high-frequency coupler 619. Thus, through this connection method, the no-load voltage of the welding machine 4 can supply power to the high-frequency arc ignition module 612 after the relay 615 is energized. The high-frequency arc ignition module 612 automatically stops working after operating for 2-3 seconds after the relay 615 is energized, ceasing to output high frequency until the next trigger. The high-frequency arc ignition module 612 can only be energized after the relay 615 is energized and a power circuit is formed. Therefore, the high-frequency arc ignition module 612 and the high-frequency coupler 619 only begin to work after the welding circuit is established, improving the automation level of the control device while saving energy and reducing consumption. In addition, the positive and negative output terminals of the high-frequency arc initiation module 612 are electrically connected to the two ends of the high-frequency coupler 619, respectively. After the high-frequency arc initiation module 612 is working, it sends a high-frequency signal to the high-frequency coupler 619, and the high-frequency coupler 619 outputs the obtained high-frequency signal to the negative output interface 65 via the welding cable.

[0057] In this embodiment, the delayed turn-on module 610 and the delayed turn-off module 611 are connected in parallel and both are powered by the battery 618. The relay 615 and the solenoid valve 616 are also powered by the battery 618. A micro switch 68 and a micro switch socket 66 connected in series with it are connected in series in the circuit from the battery 618 to the delayed turn-on module 610 and the delayed turn-off module 611, thereby controlling whether the battery 618 supplies power to the delayed turn-on module 610 and the delayed turn-off module 61 by switching the micro switch 68 on and off.

[0058] The structure and working principle of the micro switch 68, delayed turn-on module 610, delayed turn-off module 611, high-frequency arc initiation module 612, battery charging management module 613, DC-DC power supply module 614, relay 615, solenoid valve 616, battery 618 and high-frequency coupler 619 mentioned above are all existing technologies. The specific models and connection methods are only required to meet the working process and control method in this specification, and will not be described in detail here.

[0059] A control method for an external control device for manual tungsten inert gas welding includes the following control process.

[0060] S1: See Figure 4 As shown, the argon gas input interface 63 is connected to the argon gas cylinder 1, the negative input interface 62 is electrically connected to the negative terminal of the welding machine 4 via a cable, the conductive clamp 64, which is electrically connected to the DC-DC power module 614, is electrically connected to the positive terminal of the welding machine 4 via a cable, the negative output interface 65 is electrically connected to the welding torch 2 via a cable, the argon gas output interface 67 is connected to the welding torch 2, and the positive terminal of the welding machine 4 is electrically connected to the workpiece 5. The open-circuit voltage of the DC welding machine 4 is stabilized at 12V after being stepped down by the DC-DC module 614 and then supplies power to the battery charging management module 613. The battery charging management module 613 detects the charge of the battery 618 and can output 12V voltage to automatically turn on and off the charging of the battery 618.

[0061] S2: When the micro switch 68 is turned on, the conduction signal is transmitted through the micro switch socket 66 to the delayed shutdown module 611 and the delayed conduction module 610 to provide operating voltage to both of them;

[0062] After the delayed shutdown module 611 is powered on, it controls the solenoid valve 616 to open, so that argon gas is output to the welding torch 2 through the argon gas input interface 63, the hose 617, and the argon gas output interface 67 in sequence. The argon gas forms an argon gas protection area around the nozzle of the welding torch 2.

[0063] After the delayed conduction module 610 is energized for a certain period of time (the time is adjustable), it controls the relay 615 to engage and conduct, so that the negative input interface 62, the relay 615, the high-frequency coupler 619, the negative output interface 615 are connected to the welding gun 2, thereby establishing a welding circuit.

[0064] When relay 615 is energized, high-frequency arc ignition module 612 is powered on and sends a high-frequency signal to high-frequency coupler 619 for a certain period of time (the time is adjustable and can be 2-3 seconds). High-frequency coupler 619 outputs the obtained high-frequency signal to the tungsten electrode of welding torch 2 through negative output interface 65, breaking down the 1-2mm gap between the tungsten electrode and the workpiece, thereby igniting the arc in the area with existing argon protection.

[0065] S3: When welding is completed, the shut-off signal is transmitted to the delayed conduction module 610 via the microswitch socket 66 when the microswitch 68 is released.

[0066] After the delayed conduction module 610 loses power, it immediately shuts off the working voltage of the relay 615 to control the relay 615 to disconnect the negative input interface 62, the relay 615, the negative output interface 65 from the welding gun 2, and the arc is extinguished.

[0067] While the delayed conduction module 610 loses power, the delayed shutdown module 611 delays for a certain period of time (the time is adjustable) before shutting off the working voltage of the solenoid valve 616 to control the solenoid valve 616 to close, thereby disconnecting the passage from the argon cylinder 1 to the welding torch 2 and shutting off the argon flow. This achieves the function of first cutting off the power and extinguishing the arc and then cutting off the gas when stopping welding. At this time, the high-temperature molten pool is protected by argon gas from being oxidized by air, thus ensuring the welding quality at the arc termination point.

[0068] This invention proposes a novel control device and method for argon arc welding. The device features a simple structure and, through components housed within the main unit casing, achieves comprehensive and effective control of gas, electricity, and arc ignition when using a simple argon arc welding torch. This reduces the difficulty of operation for welders while improving welding quality, safety, and economy. During use, the welder only needs to press a microswitch to automatically control all elements required for the welding process, maximizing the utilization of argon gas and reducing resource waste.

[0069] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A manual GTAW external control device, characterized by: include: A welding circuit switching module is used to control the on / off state of the welding circuit and includes a negative input interface, a relay and a negative output interface connected in series. Argon gas on / off module: used to control the on / off of argon gas between argon cylinder and welding torch, and includes an argon gas input interface, a solenoid valve, a hose and an argon gas output interface connected in series. Delayed shutdown module: used to control the solenoid valve to open when it is powered on and to control the solenoid valve to close after a certain period of time when it is de-powered; Delayed turn-on module: used to control the relay circuit to turn on after a certain period of time when it is powered on, and to control the relay circuit to turn off when it is de-powered; DC-DC power supply module: used to step down the open-circuit voltage of the welding machine and supply power to the delayed turn-on module, delayed turn-off module, relay, and solenoid valve respectively; High-frequency coupler: connected in series between the negative output interface and the output terminal of the relay; High-frequency arc initiation module: Powered by the welding machine's open-circuit voltage, it sends a high-frequency signal to the high-frequency coupler after being powered on. The high-frequency coupler outputs the received high-frequency signal to the negative output interface. The high-frequency arc initiation module is powered on after the relay is energized and sends a high-frequency signal to the high-frequency coupler for 2-3 seconds, and then automatically stops working until it is triggered again when the relay is energized again. Switching module: Used to control the circuit connection and disconnection between the DC-DC power module and the delayed turn-on module, delayed turn-off module, relay, and solenoid valve respectively; It also includes a storage battery, and the switching module controls the circuit connection and disconnection between the storage battery and the delayed turn-on module, the delayed turn-off module, the relay, and the solenoid valve; It also includes a battery charging management module, which is powered by a DC-DC power module. The battery charging management module is used to charge the battery and provide operating voltage to the delayed turn-on module, the delayed turn-off module, the relay, and the solenoid valve. The positive input terminal of the high-frequency arc initiation module is electrically connected to the positive input terminal of the DC-DC power supply module, and the negative input terminal of the high-frequency arc initiation module is electrically connected to the negative output interface. A conductive clamp is electrically connected to the positive input terminal of the DC-DC power module, and the conductive clamp is used to electrically connect to the positive terminal of the welding machine. The positive input terminal of the DC-DC power module is electrically connected to the positive terminal of the welding machine, and the negative input terminal of the DC-DC power module is electrically connected to the negative input interface.

2. The external control device for manual GTAW according to claim 1, characterized in that: The switching module includes a micro switch and a micro switch socket connected in series with the micro switch. The micro switch socket is electrically connected to the input terminals of the delayed turn-on module and the delayed turn-off module, respectively. The micro switch controls the circuit connection and disconnection between the DC-DC power module and the battery and the delayed turn-on module, the delayed turn-off module, the relay, and the solenoid valve, respectively.

3. The external control device for manual GTAW according to claim 1, characterized in that: It also includes a main unit housing, and the welding circuit switching module, argon gas switching module, delayed shutdown module, DC-DC power supply module, and switch module are disposed inside the main unit housing. A handle is provided on the main unit housing.

4. A control method based on the external control device for manual tungsten inert gas welding as described in claim 1, characterized in that: This includes the following control processes: S1: Connect the argon gas input interface to the argon gas cylinder, connect the negative input interface to the negative terminal of the welding machine via a cable, connect the DC-DC power module to the positive terminal of the welding machine via a cable, connect the negative output interface to the welding torch via a cable, connect the argon gas output interface to the welding torch, and connect the positive terminal of the welding machine to the workpiece. S2: Turn on the switch module, and the delayed shutdown module and the delayed conduction module are powered on; After being powered on, the delayed shutdown module controls the solenoid valve to open, so that argon gas is output to the welding torch through the argon gas input interface, the hose and the argon gas output interface in sequence. After the delayed conduction module is powered on for a certain period of time, it controls the relay to engage and conduct, so that the negative input interface, the relay, the negative output interface and the welding gun are connected. When the relay is energized, the high-frequency arc ignition module is powered on and sends a high-frequency signal to the high-frequency coupler for a certain period of time. The high-frequency coupler outputs the obtained high-frequency signal to the tungsten electrode of the welding torch through the negative output interface, thereby igniting the electric arc in the area with existing argon protection. S3: When welding is complete, turn off the switch module; After the delayed conduction module loses power, it controls the relay to disconnect, thereby extinguishing the arc by disconnecting the negative input interface, the relay, the negative output interface from the welding gun. When the delayed conduction module loses power, the delayed shutdown module controls the solenoid valve to close after a certain delay, thus disconnecting the passage from the argon cylinder to the welding torch.

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