Plasma-tig integrated welding equipment capable of adjusting arc thermal distribution

Abstract

The application discloses a plasma-TIG integrated welding device capable of adjusting arc thermal power distribution, which comprises a plasma welding torch and a control circuit. The plasma welding torch comprises a plasma arc power supply, a high-frequency generator and a tungsten electrode; the plasma arc power supply is connected with the tungsten electrode through the high-frequency generator, and the tungsten electrode faces the workpiece directly; the control circuit comprises a dynamic push-pull device, and the dynamic push-pull device is connected with the tungsten electrode. The device improves the plasma welding circuit and the arc starting mode. When plasma welding is carried out, the dynamic push-pull device is used to make the tungsten electrode move downward before arc starting, the distance between the workpiece and the tungsten electrode is reduced, the arc is directly started with the workpiece, the dynamic push-pull device is used to make the tungsten electrode move upward after arc starting, and the tungsten electrode is recycled into the nozzle. Through the triple action of mechanical compression, thermal compression and magnetic compression, a stable constrained arc is formed, the plasma welding enters into a normal working state, and the conversion between the plasma welding and the TIG welding is realized.

Description

Technical Field

[0001] This invention relates to the field of high-efficiency plasma welding technology, specifically a novel integrated plasma-TIG welding equipment with adjustable arc heat distribution. Background Technology

[0002] Plasma arc welding is a high-energy-density welding process. Compared with laser welding and electron beam welding, plasma arc welding equipment is less expensive, easier to operate, and has greater adaptability to joint gaps, thus having broad application prospects in the processing and manufacturing of various alloy material structures. Specifically, perforated plasma arc welding is suitable for welding stainless steel with a thickness of 3-8mm, titanium alloys with a thickness of less than 12mm, and medium-thickness low-carbon steel and low-alloy structural steel. Using a variable polarity plasma arc welding power source, single-sided welding of aluminum and aluminum alloys with a thickness of 15mm is possible.

[0003] Currently, in plasma welding, the electric arc is generated by a tungsten electrode and the workpiece, with the positive and negative terminals of the main power supply connected to the workpiece and the tungsten electrode, respectively. Due to the relatively long distance between the tungsten electrode and the workpiece, igniting the arc requires first igniting a single arc between the tungsten electrode and the nozzle. The tungsten electrode is heated, causing a high-temperature gas flow from the nozzle orifice, which is then sprayed onto the workpiece surface, forming a high-temperature gas layer containing charged particles between the workpiece and the tungsten electrode. Subsequently, under the relatively high open-circuit voltage of the main power supply, the arc can automatically transfer to burn between the tungsten electrode and the workpiece. This invention discloses a novel integrated plasma-TIG welding device with adjustable arc heat distribution. The plasma arc power supply, high-frequency generator, tungsten electrode, and workpiece form the plasma welding circuit, while a dynamic push-pull device is connected to the tungsten electrode to form a control circuit. The dynamic push-pull device is fixedly connected to the plasma welding torch and tightly coupled to the tungsten electrode connecting rod. The movement of the tungsten electrode is controlled by the dynamic push-pull device to regulate the arc heat distribution. Specifically, this equipment can control the extension length of the tungsten electrode to change the magnitude of the arc force and the range of arc heat input, thereby regulating the weld formation and improving the process flexibility of plasma welding. The equipment improves the plasma welding circuit and arc initiation method. Before arc initiation, a dynamic push-pull device moves the tungsten electrode downwards, reducing the distance between the workpiece and the tungsten electrode, allowing the arc to directly ignite with the workpiece. After arc initiation, the dynamic push-pull device moves the tungsten electrode upwards and retracts it into the nozzle. Utilizing the triple action of mechanical compression, thermal compression, and magnetic compression, a stable confined arc is formed, entering the normal working state of plasma welding. This equipment can also achieve the conversion between plasma welding and TIG welding. The dynamic push-pull device controls the position of the tungsten electrode during operation and adjusts the water, ion gas, and shielding gas to achieve the conversion between plasma welding and TIG welding. Summary of the Invention

[0004] This invention proposes a novel integrated plasma-TIG welding device with adjustable arc heat distribution. Firstly, the device utilizes a dynamic push-pull mechanism to adjust the height of the tungsten electrode, thereby controlling the arc force and the arc heat input distribution range. It also enables switching between plasma welding and TIG welding modes. Secondly, the device simplifies the plasma arc initiation method and welding circuitry, eliminating the need for arc initiation between the nozzle and the tungsten electrode, thus eliminating the need for an arc-maintaining power supply, saving costs, and improving the digitalization and integration of the plasma equipment.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A novel integrated plasma-TIG welding device with adjustable arc heat distribution includes a plasma welding torch and a control circuit. The plasma welding torch includes a plasma arc power supply, a high-frequency generator, and a tungsten electrode. The plasma arc power supply is connected to the tungsten electrode via the high-frequency generator, and the tungsten electrode faces the workpiece. The control circuit includes a dynamic push-pull device, which is connected to the tungsten electrode.

[0007] The arc ignition process of the plasma welding torch has changed from the previous method of first igniting a secondary arc and then the main arc. Now, a dynamic push-pull device lowers the tungsten electrode to extend it beyond the nozzle, igniting the arc at high frequency. After the arc is formed, the dynamic push-pull device retracts the tungsten electrode, and a stable plasma arc is formed under the compression of the arc-ionized gas and the plasma welding torch. The control circuit is responsible for controlling and adjusting the movement of the tungsten electrode and the corresponding changes in the welding current.

[0008] Furthermore, the dynamic push-pull device includes a movement control device (1), a high-temperature resistant insulating connecting rod (2), and a specially made tungsten electrode clamp (3). The movement control device (1) has a built-in drive motor and gear. The output shaft of the drive motor is connected to the gear through a reducer. The gear is connected to the high-temperature resistant insulating connecting rod (2) through a crank-slider mechanism. The high-temperature resistant insulating rod (2) can be moved up and down within a range of 10mm by adjusting the speed of the drive motor. The high-temperature resistant insulating connecting rod (2) is made of high-temperature resistant insulating material. The specially made tungsten electrode clamp (3) is set at the end of the high-temperature resistant insulating connecting rod (2) for tight connection with the tungsten electrode. The clamping size is changed according to the size of the tungsten electrode. The dynamic push-pull device moves the tungsten electrode by controlling the movement of the high-temperature resistant insulating rod (2) through the movement control device (1), thereby controlling the amount of tungsten electrode retraction.

[0009] Furthermore, the dynamic push-pull device can adjust the tungsten electrode movement range from +4mm to -4mm, with an adjustment accuracy of 0.1mm, using the plasma welding torch nozzle as the reference plane. The dynamic push-pull device is connected to an external computer control terminal. The computer control terminal adjusts the drive motor frequency according to experimental requirements, controls the gear rotation speed and rotation range, and thus controls the speed and magnitude of the tungsten electrode extension and retraction.

[0010] Furthermore, the dynamic push-pull device is controlled by a computer-controlled motor that drives the gear and the high-temperature resistant insulating connecting rod (2) to move up and down, thereby controlling the up and down movement of the tungsten electrode. The dynamic push-pull device is connected to the motion system of the plasma welding torch. By controlling the position of the tungsten electrode, the magnitude of the arc force and the range of arc heat input are changed, thereby achieving dynamic regulation of the arc heat distribution. This allows for fine-tuning of the welding process during welding, increasing the flexibility of the welding process. When the tungsten electrode moves upward, the arc is compressed, the arc force increases, and the range of heat input decreases, improving the arc's penetration ability. When the tungsten electrode moves downward, the arc compression effect weakens, the arc force weakens, and the range of heat input increases, increasing the weldable area.

[0011] Furthermore, the conversion between plasma welding and TIG welding is achieved by controlling a dynamic push-pull device. The tungsten electrode is moved downwards to extend beyond the nozzle, and the ion gas and water channels are shut off to achieve TIG welding. The dynamic push-pull device moves the tungsten electrode downwards, reducing the distance between the workpiece and the electrode, allowing the current between the positive and negative electrodes to break down the air and generate a stable arc. After arc ignition, the dynamic push-pull device moves the tungsten electrode upwards and retracts it into the nozzle. Utilizing the triple action of mechanical compression, thermal compression, and magnetic compression, a stable confined arc is formed, achieving plasma welding.

[0012] Furthermore, the tungsten electrode is made of cerium-tungsten alloy, pure tungsten, or thorium-tungsten alloy.

[0013] Furthermore, the ionizing gas is argon or an argon-helium mixture, the ionizing gas flow rate is 1-25 L / min, the welding current is 1-500 A, and the applicable welding materials include stainless steel, aluminum alloy, and low-alloy high-strength steel.

[0014] The beneficial effects of this invention are:

[0015] (1) The present invention utilizes a dynamic push-pull device to adjust the distance between the tungsten electrode and the workpiece, thereby changing the range of action of the arc force and heat input, realizing thermal control during the plasma welding process, and improving the process flexibility of the plasma welding process.

[0016] (2) The present invention improves the arc initiation method and welding circuit of plasma welding, eliminating the need for an arc-starting power supply, simplifying the welding circuit, saving costs, and improving the integration and digitization of equipment.

[0017] (3) By adjusting the position of the tungsten electrode, the present invention realizes the conversion between plasma welding and TIG welding modes, and uses a single plasma welding torch to achieve the two welding processes, thus enabling the arbitrary switching between plasma welding and TIG welding. Attached Figure Description

[0018] Figure 1A new type of integrated plasma-TIG welding equipment with adjustable arc heat distribution.

[0019] Figure 2 It is a dynamic push-pull device.

[0020] In the figure, (1) is the movement control device; (2) is the high-temperature resistant insulating connecting rod; and (3) is the specially made tungsten electrode clamp.

[0021] Figure 3 Comparison of plasma welding equipment before and after the improvement. (a) shows the plasma welding equipment before the improvement, and (b) shows the plasma welding equipment after the improvement.

[0022] Figure 4 Schematic diagrams of the working states of two welding processes. (a) TIG welding working state; (b) Plasma welding working state. Detailed Implementation

[0023] To further understand the content, features, and effects of this invention, the following embodiments are provided, and detailed descriptions are given below in conjunction with the accompanying drawings:

[0024] The basic ideas of this invention are as follows: First, a dynamic push-pull device is added to the plasma welding torch to control the extension and retraction of the tungsten electrode, regulate the thermal distribution of the arc, and improve the process flexibility of plasma welding. Second, this device simplifies the plasma arc initiation method and welding circuit, eliminating the need for arc initiation between the nozzle and the tungsten electrode, i.e., eliminating the need for an arc-maintaining power supply, saving costs and improving the digitalization and integration of plasma equipment. Third, by adjusting the position of the tungsten electrode, the conversion between plasma welding and TIG welding modes is realized, using a single plasma welding torch to achieve both welding processes, and enabling arbitrary switching between plasma welding and TIG welding.

[0025] like Figure 1 The diagram shows a novel integrated plasma-TIG welding equipment with adjustable arc heat distribution. The welding power source, high-frequency generator, tungsten electrode, and workpiece form the welding circuit, while the dynamic push-pull device and tungsten electrode form the control circuit. Figure 3 The device shown changes the arc initiation process of plasma welding from the previous method of first initiating a secondary arc and then the main arc. Instead, a dynamic push-pull device lowers the tungsten electrode, causing it to extend beyond the nozzle, and initiates the arc at high frequency. After the arc is formed, the dynamic push-pull device retracts the tungsten electrode, and a stable plasma arc is formed under the compression of the ionized gas and the plasma welding torch. The control circuit controls the movement of the tungsten electrode and the corresponding changes in the welding current.

[0026] like Figure 2The dynamic push-pull device for controlling the movement of a tungsten electrode, as shown, includes a movement control device (1), a high-temperature resistant insulating connecting rod (2), and a specially designed tungsten electrode clamp (3). The movement control device (1) has a built-in drive motor, and the high-temperature resistant insulating rod (2) can be moved up and down within a 10mm range by adjusting the speed of the built-in drive motor. The high-temperature resistant insulating connecting rod (2) is made of high-temperature resistant insulating material. The specially designed tungsten electrode clamp (3) is used to tightly connect with the tungsten electrode, and its clamping size can be changed according to the size of the tungsten electrode. The dynamic push-pull device controls the movement of the high-temperature resistant insulating rod through the movement control device to achieve the movement of the tungsten electrode, thereby controlling the amount of inward retraction of the tungsten electrode.

[0027] The dynamic push-pull device allows for a tungsten electrode movement range of +4mm to -4mm with an adjustable accuracy of 0.1mm (based on the plasma welding torch nozzle). The device is connected to an external computer control unit, which can adjust the motor frequency, control the gear rotation speed and range, and control the speed and extent of the tungsten electrode extension and retraction according to experimental requirements.

[0028] The dynamic push-pull device is connected to the plasma welding torch. By controlling the extension length of the tungsten electrode, the magnitude of the arc force and the range of arc heat input are changed, achieving dynamic control of the arc heat distribution. This allows for fine-tuning of the welding process during welding, increasing its flexibility. When the tungsten electrode moves upward, the arc is compressed, the arc force increases, and the range of heat input decreases, improving the arc's penetration ability. When the tungsten electrode moves downward, the arc compression weakens, the arc force decreases, and the range of heat input increases, expanding the weldable area.

[0029] like Figure 4 The diagram illustrates how a dynamic push-pull device can be used to switch between plasma welding and TIG welding. Moving the tungsten electrode downwards to extend it from the nozzle, and shutting off the ion gas and water supply, initiates TIG welding. The dynamic push-pull device then moves the tungsten electrode downwards, reducing the distance between the workpiece and the electrode, allowing the current between the positive and negative electrodes to break down the air and generate a stable arc. After arc ignition, the dynamic push-pull device moves the tungsten electrode upwards, retracting it into the nozzle. Utilizing the triple action of mechanical compression, thermal compression, and magnetic compression, a stable confined arc is formed, achieving plasma welding. This equipment allows for seamless switching between plasma welding and TIG welding, making the plasma welding torch a multi-purpose weapon.

[0030] Specific operation example 1:

[0031] Taking the welding of a 10mm thick, 10cm long butt weld without beveling using a new type of plasma-TIG integrated welding equipment as an example, according to... Figure 1 Connect the required equipment. The power supply used during welding is a variable polarity plasma arc welding power supply. The three-dimensional motion mechanism drives the plasma welding torch and other devices to move.

[0032] Specifically, the following steps are included:

[0033] Step 1: Sand the surfaces of the two aluminum plates to be welded with sandpaper to remove surface oil and oxide film. Fix the two aluminum plates onto the worktable. Set the ion gas flow rate to 2.8L / min and the shielding gas flow rate to 15L / min. Turn on the variable polarity plasma arc power supply and set the plasma arc EN stage current to 290A and the EP stage current to 270A. Adjust the relative position of the plasma welding torch and the aluminum plate to be welded using the three-dimensional motion mechanism controller, so that it is positioned 4mm above the aluminum plate.

[0034] Step 2: Set the retraction speed of the dynamic push-pull device according to the welding current, start the dynamic push-pull device, and move the tungsten electrode downwards to -4mm.

[0035] Step 3: Start the plasma welding power supply and use the high-frequency generator to ignite the arc and generate the initial electric arc.

[0036] Step 4: Activate the dynamic push-pull device to move the tungsten electrode upwards to +4mm, reaching the normal operating state for plasma welding. Simultaneously, increase the current according to the predetermined waveform to the predetermined EP current for welding. Start the wire feeder and weld the required 10cm butt weld along the predetermined trajectory.

Claims

1. An integrated plasma-TIG welding device with adjustable arc heat distribution, comprising a plasma welding torch and a control circuit; the plasma welding torch includes a plasma arc power supply, a high-frequency generator, and a tungsten electrode; the plasma arc power supply is connected to the tungsten electrode via the high-frequency generator, and the tungsten electrode faces the workpiece; the control circuit includes a dynamic push-pull device, which is connected to the tungsten electrode; the precise control of the tungsten electrode position via the dynamic push-pull device dynamically adjusts the degree of arc restraint, thereby achieving real-time control of the arc heat distribution; The arc ignition process of the plasma welding torch has changed from the previous method of igniting the secondary arc first and then the main arc to a method in which the tungsten electrode is moved down by a dynamic push-pull device to extend it out of the nozzle, and the arc is ignited at high frequency. After the electric arc is formed, the tungsten electrode is pulled back using a dynamic push-pull device. A stable plasma arc is formed under the compression of the arc ionized gas and the plasma welding torch. The control circuit is responsible for controlling and adjusting the movement of the tungsten electrode and the corresponding changes in the welding current. The dynamic push-pull device includes a movement control device (1), a high-temperature resistant insulating connecting rod (2), and a special tungsten electrode clamp (3). The movement control device (1) has a built-in drive motor and gear. The output shaft of the drive motor is connected to the gear through a reducer. The gear is connected to the high-temperature resistant insulating connecting rod (2) through a crank-slider mechanism. The high-temperature resistant insulating connecting rod (2) can move up and down within a range of 10mm by adjusting the speed of the drive motor. The high-temperature resistant insulating connecting rod (2) is made of high-temperature resistant insulating material. The special tungsten electrode clamp (3) is set at the end of the high-temperature resistant insulating connecting rod (2) for tight connection with the tungsten electrode. The dynamic push-pull device moves the tungsten electrode by controlling the movement of the high-temperature resistant insulating connecting rod (2) through the movement control device (1), thereby controlling the amount of tungsten electrode retraction. The dynamic push-pull device can adjust the tungsten electrode movement range from +4mm to -4mm, with an adjustment accuracy of 0.1mm, using the plasma welding torch nozzle as the reference plane. The dynamic push-pull device is connected to an external computer control terminal, which adjusts the drive motor frequency, controls the gear rotation speed and rotation range according to experimental requirements, and thus controls the speed and magnitude of the tungsten electrode extension and retraction.

2. The plasma-TIG integrated welding equipment with adjustable arc heat distribution according to claim 1, characterized in that, The dynamic push-pull device is driven by a computer control program to drive a motor to move gears and a high-temperature resistant insulating connecting rod (2) up and down, thereby controlling the up and down movement of the tungsten electrode. The dynamic push-pull device is connected to the motion system of the plasma welding torch. By controlling the position of the tungsten electrode, the magnitude of the arc force and the range of arc heat input are changed, thereby achieving dynamic regulation of the arc heat distribution. When the tungsten electrode moves upward, the arc is compressed, the arc force increases, the range of heat input decreases, and the arc penetration ability is improved. When the tungsten electrode moves downward, the arc compression effect weakens, the arc force weakens, the range of heat input increases, and the weldable area increases.

3. The plasma-TIG integrated welding equipment with adjustable arc heat distribution according to claim 1, characterized in that, The conversion between plasma welding and TIG welding is achieved by controlling a dynamic push-pull device. The tungsten electrode is moved downward to extend out of the nozzle, and the ion gas and water circuit are closed to achieve TIG welding. The dynamic push-pull device moves the tungsten electrode downward to reduce the distance between the workpiece and the tungsten electrode, so that the current between the positive and negative electrodes breaks down the air to generate a stable arc. After the arc is ignited, the dynamic push-pull device moves the tungsten electrode upward and retracts it into the nozzle. The triple action of mechanical compression, thermal compression and magnetic compression forms a stable confined arc to achieve plasma welding.

4. The plasma-TIG integrated welding equipment with adjustable arc heat distribution according to claim 1, characterized in that, The tungsten electrode is made of cerium-tungsten alloy, pure tungsten, or thorium-tungsten alloy.

5. The plasma-TIG integrated welding equipment with adjustable arc heat distribution according to claim 1, characterized in that, The ionizing gas is argon or an argon-helium mixture, with a flow rate of 1–25 L / min and a welding current of 1–500 A. The applicable welding materials include stainless steel, aluminum alloy, and low-alloy high-strength steel.

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