WO2021027217A1 - 一种适用于超窄间隙的gtaw焊接系统及焊接方法 - Google Patents

一种适用于超窄间隙的gtaw焊接系统及焊接方法 Download PDF

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Publication number
WO2021027217A1
WO2021027217A1 PCT/CN2019/126482 CN2019126482W WO2021027217A1 WO 2021027217 A1 WO2021027217 A1 WO 2021027217A1 CN 2019126482 W CN2019126482 W CN 2019126482W WO 2021027217 A1 WO2021027217 A1 WO 2021027217A1
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Prior art keywords
welding
tungsten electrode
rotating
ultra
wire feeding
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PCT/CN2019/126482
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English (en)
French (fr)
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贾传宝
吴玮
魏斌
米什拉·萨钦
周继辉
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山东大学
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Priority to US16/845,340 priority Critical patent/US11571763B2/en
Publication of WO2021027217A1 publication Critical patent/WO2021027217A1/zh

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/16—Arc welding or cutting making use of shielding gas
    • B23K9/167—Arc welding or cutting making use of shielding gas and of a non-consumable electrode
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/12—Automatic feeding or moving of electrodes or work for spot or seam welding or cutting
    • B23K9/124—Circuits or methods for feeding welding wire
    • B23K9/125—Feeding of electrodes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/12—Automatic feeding or moving of electrodes or work for spot or seam welding or cutting
    • B23K9/133—Means for feeding electrodes, e.g. drums, rolls, motors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/32—Accessories
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/32—Accessories
    • B23K9/325—Devices for supplying or evacuating shielding gas

Definitions

  • the invention relates to a GTAW welding system and a welding method suitable for ultra-narrow gaps, and belongs to the technical field of narrow gap welding.
  • Narrow-gap welding technology is a method for achieving high-efficiency and high-quality welding of thick plates using fully automatic welding devices and arc control technology in narrow gap grooves.
  • Narrow-gap welding technology is usually applied to the welding of low-alloy steel thick-walled vessels and some important alloy components.
  • narrow-gap welding technology guarantees the high welding quality of thick plates.
  • the cross-sectional area of the groove is reduced by more than 50%, which effectively reduces the consumption cost of welding filling materials, and can reduce the welding level, thereby effectively reducing the welding stress and deformation of the workpiece.
  • the ultra-narrow gap welding technology refers to the situation where the groove gap width reaches 6mm and below.
  • the arc characteristics become more sensitive, the arc is unstable, and the arc climbing on the sidewall, burning on the sidewall and welding wire burnback are prone to occur.
  • researchers using flux ribbons or flux sheets to confine the arc can solve the above problems to a certain extent, but there are problems that the welding process is complicated or the stability of the welding process is difficult to guarantee.
  • the non-axisymmetric rotating tungsten pole narrow-gap welding process uses a non-axisymmetric tungsten pole.
  • the tungsten pole rotates in the gap to control the arc's periodic swing.
  • the structure is simple and the gap width is not affected by the size of the gap, which can effectively Solve some problems in ultra-narrow gap welding. With the gradual increase of plate thickness, the difficulty of welding also increases.
  • the problems of ensuring the coaxiality of tungsten rotation, effective fusion of side walls, stable combustion of the arc and gas protection in deeper gaps need to be solved.
  • the present invention provides a GTAW welding system suitable for ultra-narrow gaps.
  • the present invention also provides a welding method using the above welding system.
  • a GTAW welding system suitable for ultra-narrow gaps including argon arc welding power supply, TIG welding torch, welding trolley, wire feeding device, and gas protection device;
  • the TIG welding gun includes a welding gun shell, a rotating motor, a central rotating shaft, a rotating tungsten electrode, a conductive system, and an air supply system.
  • the rotating motor is connected to the rotating tungsten electrode through the central rotating shaft.
  • the rotating tungsten electrode is non-axisymmetric tungsten electrode.
  • the argon arc welding power supply is connected and provides electricity, and the gas supply system is used to provide shielding gas into the welding gun; the rotating tungsten electrode is driven to rotate periodically by the rotating motor;
  • the TIG welding torch is fixed on the welding trolley, and the TIG welding torch is moved by the welding trolley;
  • the wire feeding device is mechanically connected with the TIG welding gun and moves synchronously with the welding gun; the wire feeding angle can be adjusted as required; the automatic wire feeding device is matched with the welding power source to realize the delayed wire feeding during the welding process, the wire drawing in advance and the wire feeding parameters Adjustment, etc.;
  • the gas protection device is a shell, the shell is covered above the workpiece to be welded, the shell is provided with a welding gun mouth and an air inlet, the TIG welding gun penetrates the welding gun mouth, and the shell is connected to an external protective gas system through the air inlet.
  • the gas supply system of the TIG welding torch adopts the gas protection structure of the ordinary TIG welding torch. After the gas enters the welding torch, it first fills the gas chamber in the gun body, and is sprayed out through the ceramic nozzle after buffering. It has a certain restraint effect on the arc under the tungsten electrode and protects the arc. The molten pool below.
  • the front end of the TIG welding gun is provided with a ceramic nozzle, and the inner wall of the ceramic nozzle is processed with a spiral air guide groove. It has a certain acceleration effect on the airflow, which can make the gas reach deeper in the groove.
  • the argon gas enters the shell gently through the air inlet, and forms an argon atmosphere after dispersing to protect the weld area after welding to prevent oxidation of the weld.
  • the TIG welding gun is fixedly connected to the welding trolley through threaded bolts.
  • the distance between the welding gun and the workpiece in the horizontal direction and the vertical height direction can be adjusted by adjusting the thread.
  • the torch shell of the TIG welding torch is made of aluminum alloy to reduce the weight of the gun body, and the contact position with the fixture is made of insulating bakelite to prevent the high frequency of the arc ignition from affecting the welding torch.
  • the central rotating shaft is made of brass material, which can reduce the mass of the welding gun and effectively reduce the axial load.
  • the brass material satisfies the mechanical properties, thermal conductivity and electrical conductivity, and has high economic benefits.
  • An electrically insulated deep groove ball bearing is installed at the connection between the central rotating shaft and the rotating tungsten pole, which can effectively resist the impact of current on the bearing surface and lubricating oil while meeting the coaxial rotation accuracy of the central rotating shaft, slow down the corrosion speed of the bearing surface and increase the bearing
  • the wear resistance of the surface extends the service life of the bearing.
  • the end of the central rotating shaft is tightly threaded with the rotating tungsten electrode through a reverse wire.
  • the rotating tungsten electrode ensures good air tightness, and on the other hand, it ensures that the screw thread becomes tighter and tighter during the rotation process.
  • shielding gas is circulated in the torch body to accelerate the heat dissipation speed of the central rotating shaft, rotating tungsten electrode and conductive copper block.
  • the bottom end of the rotating tungsten electrode is provided with an inclined surface.
  • the inclined plane forms an angle with the central axis of the rotating tungsten electrode.
  • the included angle between the inclined surface and the central axis of the rotating tungsten electrode is 45°.
  • the arc shape is similar to that of ordinary tungsten arc, and it cannot effectively heat the side walls of the workpiece to be welded on both sides of the narrow gap, and the fusion of the two side walls is poor; when the inclination angle is too large, the arc length Too long, the arc stiffness is not enough, it is not conducive to the stable combustion of the arc, the best effect is when the tip is inclined at 45°.
  • the tip of the inclined surface of the rotating tungsten electrode is provided with a blunt surface platform. Processing the tip of the tungsten electrode into a platform can effectively improve the stability of the arc on the one hand, and on the other hand, compared to the tip of the tungsten electrode, processing the platform can effectively improve the burning of the tungsten electrode during use.
  • the rotating electric machine is connected to the central rotating shaft through a coupling.
  • the welding system further includes a PC and a hardware control circuit, the rotating motor is connected to the PC, and the pulse frequency of the motor is adjusted through the PC and the hardware control circuit to control the rotation of the rotating tungsten electrode.
  • the pulse frequency of the stepping motor is controlled by the PC and the control circuit to control the acceleration and deceleration of the stepping motor.
  • the initial value of the timer decreases by one value, the pulse period decreases, and the pulse frequency increases accordingly, and the motor is in the acceleration phase; when entering the deceleration phase, each time a pulse is generated, the initial value of the timer increases A value, the pulse period increases, and the pulse frequency decreases.
  • the non-uniform rotation of the tungsten pole in the gap is controlled by controlling the motor output periodic trigonometric function waveform speed, so that the tungsten pole tip rotates to the two side walls at the slowest speed, and when it rotates to the middle of the gap, the speed is the fastest. Increase the residence time of the arc on both side walls, so that more heat is used to heat the two side walls in an arc swing cycle.
  • the shell is a hollow square shell, and the welding torch mouth and the gas passage are arranged on the top surface of the shell.
  • one end of the housing is connected to the TIG welding gun through a sliding rod.
  • the shell can be adjusted in height along the sliding rod and move synchronously with the welding gun.
  • a backing plate is provided under the workpiece to be welded, and the backing plate is provided with an air groove along the welding seam, and one end of the air groove is connected with an external shielding gas system.
  • a shielding gas is also passed under the workpiece to be welded.
  • an argon atmosphere is formed to protect the back of the workpiece, and on the other hand, it can accelerate the heat dissipation and cooling of the weldment and improve the welding efficiency.
  • the backing plate is made of brass material.
  • the wire feeding device includes a wire feeding tube, and the wire feeding tube is a square tube.
  • the size of the wire feeding tube in the vertical narrow gap direction can be reduced, which facilitates the movement of the wire feeding tube in the gap; on the other hand, it is conducive to accurately feed the wire directly under the tungsten electrode to prevent During the adjustment, due to the axial rotation of the wire feed tube, the welding wire is not accurately positioned in the ultra-narrow gap and deviates from the tungsten electrode.
  • the wire feeding tube needs to be bent into a certain arc to feed the wire into the gap, so the sent wire will also be bent into a certain arc, accurately position the wire feeding tube in the middle of the gap, and keep it on the same plane as the tungsten electrode Above, the stability of the welding process and the shape of the weld can be improved.
  • a welding method using the above-mentioned GTAW welding system suitable for ultra-narrow gaps includes the following steps:
  • step (2) After the welding of the first layer is completed, use the argon gas delayed in the gas protection device to cool, and then repeat step (2) to weld the next layer.
  • the size of the rotating tungsten electrode and the position of the tungsten electrode are adjusted according to the size of the gap: in the horizontal direction of the vertical weld, the tungsten electrode is located in the middle of the gap to prevent the tungsten electrode from moving to the distance between the two side walls. Produce large deviations;
  • the height of the tungsten electrode from the bottom groove is adjusted according to the gap size.
  • the specific rules are as follows: when welding a 6mm gap groove, use a 3.0mm tungsten electrode, and the tip is machined with a 45° inclined surface and a blunt surface platform. The height of the tungsten electrode tip from the bottom 3.0mm; when welding 5mm gap groove, use 2.4mm tungsten electrode, the tip is processed with 45° inclined surface and blunt surface platform, the height of tungsten electrode tip is 2.6mm from the bottom; when welding 4mm gap groove, 2.0mm tungsten is used The tip of the tungsten pole is machined with a 45° inclined surface and has a blunt surface platform. The height of the tungsten pole tip is 2.0mm from the bottom.
  • the horizontal distance between the wire feeding tube and the rotating tungsten electrode is 5 mm.
  • the vertical distance between the tip of the rotating tungsten electrode and the welding wire is 2-3 mm. Ensure the stability of the welding process and uniform weld formation.
  • step (3) after the welding of one layer is completed, use shielding gas to cool to the interlayer temperature of 45-55°C, and then repeat step (2) to weld the next layer.
  • step (3) after the welding of one layer is completed, air cooling is performed with shielding gas to an interlayer temperature of 50° C., and then step (2) is repeated for welding of the next layer.
  • step (3) during the welding process of the next layer, the welding current of the next layer is increased compared with the welding current of the previous layer, and the flow rate of the shielding gas of the next layer is decreased compared with that of the previous layer.
  • the pulse frequency of the rotating motor is adjusted by the PC and the hardware control circuit to control the non-uniform rotation of the rotating tungsten electrode, and the heating time of the rotating tungsten electrode on the sidewall is 1/2 of the cycle of one rotation. Realize the non-uniform swing of the arc.
  • the tungsten electrode rotates one circle about 1/3 of the stage starts to burn on both side walls, and the 2/3 stage of the arc will heat the welding wire and the molten pool in the middle of the gap.
  • the speed of the tungsten electrode tip turning to the sidewalls on both sides is slowed down, and the speed is increased when turning to the middle of the gap, so that during one revolution, the heating time of the sidewall is reduced from the original 1/3 cycle Transform to the current 1/2 cycle.
  • the motor control circuit can be adjusted according to the needs of different gap sizes to adjust the ratio of fast and slow rotation speeds, thereby adjusting the proportion of arc heating time of the side walls.
  • the heat input can be effectively reduced, and on the other hand, the sidewall fusion is more reliable.
  • step (2) as the gap decreases, in order to ensure good fusion of the two side walls and timely melting of the welding wire without excessive heat input, it is necessary to increase the welding speed and the tungsten rotation speed
  • the specific rules are as follows: when welding 6mm gap grooves, adjust the motor to control the average tungsten pole rotation speed to 4rps; when welding 5mm gap grooves, control the tungsten pole average rotation speed to 5rps; when welding 4mm gap grooves, control the tungsten pole average The rotation speed is 6rps. Adjusting the average speed of tungsten pole rotation according to different sizes resolves the contradiction between excessive heat input and poor fusion.
  • step (3) there is a matching relationship between the wire feeding speed, the welding speed and the heat input, the wire feeding speed adjustment interval is 1000mm/min-1250mm/min, adjusted as needed, and the welding speed adjustment interval 80mm/min- 100mm/min, the welding heat input is controlled within the range of 2.0-2.5kJ/mm by adjusting the welding current and welding speed to prevent the wire from being fed into the molten pool due to excessively fast melting and untimely melting, which affects the stability and delivery of the welding process If the wire speed is too small, the cladding metal is insufficient.
  • the technical solution of the present invention realizes the welding of thick plates and large thick plates by processing 4-6mm ultra-narrow gap U-shaped grooves. Compared with narrow gap welding, it further expands the advantages of raw material saving and effectively reduces groove processing.
  • the area increases the filling efficiency of the deposited metal, and improves the welding efficiency while reducing the heat input.
  • the technical solution of the present invention reasonably adjusts the residence time of the arc in each area in the ultra-narrow gap by periodically adjusting the tungsten electrode rotation speed, thereby adjusting the heat distribution of different positions, so that the arc has more time to heat the sidewall in one rotation cycle. Ensure effective fusion of the side walls on both sides.
  • the technical solution of the present invention sets three gas protections.
  • the gas protection device is introduced into the gas protection device in advance to form a protective atmosphere
  • the backing plate gas groove is ventilated to form a protective atmosphere environment
  • the intermediate gas path is spirally accelerated by the gas guide groove on the inner wall of the ceramic nozzle of the TIG welding gun
  • the technical solution of the present invention by processing the tungsten electrode into a non-axisymmetric tip with a platform, realizes that the arc periodically swings in an ultra-narrow gap and stably burns while reducing the burning loss of the tungsten electrode tip;
  • the wire mechanism accurately positions the welding wire in the ultra-narrow gap, which can realize the stable wire feeding of thick plates.
  • the technical scheme of the present invention drives the welding torch to move through the welding trolley, and the welding torch position adjustment device can realize the precise positioning of the welding torch and the tungsten electrode in various directions to ensure the stable progress of the welding process, and optimize the parameters according to different gaps to achieve high quality thick plates. High-efficiency all-position welding, high practicability.
  • FIG. 1 Schematic diagram of the gas protection device of the present invention
  • FIG. 2 Schematic diagram of the non-axisymmetric tungsten electrode of the present invention
  • FIG. 3 Schematic diagram of the wire feeding tube of the present invention
  • Air inlet 2. Welding gun mouth; 3. Gas protection device; 4. Backing plate; 5. Gas groove; 6. Rotating tungsten electrode; 7. Inclined surface; 8. Blunt surface platform.
  • a GTAW welding system suitable for ultra-narrow gaps including argon arc welding power supply, TIG welding torch, welding trolley, wire feeding device, and gas protection device.
  • the TIG welding gun includes a welding gun shell, a rotating motor, a central rotating shaft, a rotating tungsten electrode, a conductive system, and an air supply system.
  • the rotating motor is connected to the rotating tungsten electrode through the central rotating shaft.
  • the rotating tungsten electrode is non-axisymmetric tungsten electrode.
  • the argon arc welding power supply is connected and provides power, and the gas supply system is used to provide shielding gas into the welding gun; the rotating tungsten electrode is driven to rotate periodically by the rotating motor.
  • the TIG welding torch is fixed on the welding trolley, and the TIG welding torch is moved by the welding trolley.
  • the wire feeding device is mechanically connected with the TIG welding gun and moves synchronously with the welding gun; the wire feeding angle can be adjusted as required; the automatic wire feeding device is matched with the welding power source to realize the delayed wire feeding during the welding process, the wire drawing in advance and the wire feeding parameters Adjustment etc.
  • the gas protection device is a shell, the shell is covered above the workpiece to be welded, and the shell is provided with a welding gun mouth and an air inlet. As shown in Figure 1, the TIG welding gun penetrates the welding gun mouth, and the shell is connected by the air inlet Outside protective gas system.
  • the gas supply system of the TIG welding torch adopts the gas protection structure of the ordinary TIG welding torch. After the gas enters the welding torch, it first fills the gas chamber in the gun body, and is sprayed out through the ceramic nozzle after buffering. It has a certain restraint effect on the arc under the tungsten electrode and protects the arc. The molten pool below.
  • the front end of the TIG welding gun is equipped with a ceramic nozzle, and the inner wall of the ceramic nozzle has a spiral air guide groove, which has a certain acceleration effect on the airflow, and can make the gas reach deeper in the groove.
  • the argon gas enters the shell gently through the air inlet, and forms an argon atmosphere after dispersing to protect the weld area after welding to prevent oxidation of the weld.
  • the torch shell of the TIG welding torch is made of aluminum alloy to reduce the weight of the gun body, and the contact position with the fixture is made of insulating bakelite to prevent the high frequency of the arc ignition from affecting the welding torch.
  • the central rotating shaft is made of brass material, which can reduce the mass of the welding gun and effectively reduce the axial load.
  • the brass material satisfies the mechanical properties, thermal conductivity and electrical conductivity, and has high economic benefits.
  • An electrically insulated deep groove ball bearing is installed at the connection between the central rotating shaft and the rotating tungsten pole, which can effectively resist the impact of current on the bearing surface and lubricating oil while meeting the coaxial rotation accuracy of the central rotating shaft, slow down the corrosion speed of the bearing surface and increase the bearing
  • the wear resistance of the surface extends the service life of the bearing.
  • a GTAW welding system suitable for ultra-narrow gaps Its structure is as described in Embodiment 1, except that the TIG welding gun is fixedly connected to the welding trolley through threaded bolts. The distance between the welding gun and the workpiece in the horizontal direction and the vertical height direction can be adjusted by adjusting the thread.
  • a GTAW welding system suitable for ultra-narrow gaps Its structure is as described in Embodiment 1, except that the end of the central rotating shaft is tightly threaded with the rotating tungsten electrode through a reverse wire. On the one hand, it ensures good air tightness, and on the other hand, it ensures that the screw thread becomes tighter and tighter during the rotation process.
  • shielding gas is circulated in the torch body to accelerate the heat dissipation speed of the central rotating shaft, rotating tungsten electrode and conductive copper block.
  • a GTAW welding system suitable for ultra-narrow gaps Its structure is as described in Example 1. The difference is that the bottom end of the rotating tungsten electrode is provided with an inclined surface, and the tip of the rotating tungsten electrode is equipped with a blunt surface platform, as shown in the figure 2 shown.
  • the inclined plane forms an angle with the central axis of the rotating tungsten electrode.
  • the tungsten electrode periodically rotates in the narrow gap groove, the distance between the tip of the tungsten electrode and the two sidewalls periodically changes. According to the principle of minimum voltage, the arc is in the narrow gap. As the tungsten electrode rotates, it periodically swings and burns, effectively melting the welding wire and the fusion side wall. Processing the tip of the tungsten electrode into a platform can effectively improve the stability of the arc on the one hand, and on the other hand, compared to the tip of the tungsten electrode, processing the platform can effectively improve the burning of the tungsten electrode during use.
  • a GTAW welding system suitable for ultra-narrow gaps Its structure is as described in Embodiment 4, except that the angle between the inclined surface and the central axis of the rotating tungsten pole is 45°.
  • the arc shape is similar to that of ordinary tungsten arc, and it cannot effectively heat the side walls of the workpiece to be welded on both sides of the narrow gap, and the fusion of the two side walls is poor; when the inclination angle is too large, the arc length Too long, the arc stiffness is not enough, it is not conducive to the stable combustion of the arc, the best effect is when the tip is inclined at 45°.
  • a GTAW welding system suitable for ultra-narrow gaps Its structure is as described in Embodiment 1, except that the rotating motor is connected to the central rotating shaft through a coupling.
  • a GTAW welding system suitable for ultra-narrow gaps Its structure is as described in Embodiment 5. The difference is that the welding system also includes a PC and a hardware control circuit.
  • the rotating motor is connected to the PC and is controlled by the PC and hardware.
  • the circuit regulates the pulse frequency of the motor to control the rotation of the rotating tungsten pole.
  • the pulse frequency of the stepping motor is controlled by the PC and the control circuit to control the acceleration and deceleration of the stepping motor.
  • the initial value of the timer decreases by one value, the pulse period decreases, and the pulse frequency increases accordingly, and the motor is in the acceleration phase; when entering the deceleration phase, each time a pulse is generated, the initial value of the timer increases A value, the pulse period increases, and the pulse frequency decreases.
  • the non-uniform rotation of the tungsten pole in the gap is controlled by controlling the motor output periodic trigonometric function waveform speed, so that the tungsten pole tip rotates to the two side walls at the slowest speed, and when it rotates to the middle of the gap, the speed is the fastest. Increase the residence time of the arc on both side walls, so that more heat is used to heat the two side walls in an arc swing cycle.
  • a GTAW welding system suitable for ultra-narrow gaps Its structure is as described in Embodiment 1, except that the shell is a hollow square shell, and the welding gun mouth and the gas passage are arranged on the top surface of the shell.
  • a GTAW welding system suitable for ultra-narrow gaps Its structure is as described in Example 1, except that one end of the shell is connected to the TIG welding gun through a sliding rod.
  • the shell can be adjusted in height along the sliding rod and move synchronously with the welding gun.
  • a GTAW welding system suitable for ultra-narrow gaps Its structure is as described in Example 7. The difference is that a backing plate is provided under the workpiece to be welded, and the backing plate is provided with an air groove along the weld.
  • the protective gas system is connected.
  • a shielding gas is also passed under the workpiece to be welded.
  • an argon atmosphere is formed to protect the back of the workpiece.
  • it can accelerate the heat dissipation and cooling of the weldment and improve the welding efficiency.
  • the backing plate is made of brass.
  • a GTAW welding system suitable for ultra-narrow gaps Its structure is as described in Embodiment 10. The difference is that the wire feeding device includes a wire feeding tube, which is a square tube. Different from the conventional circular tube, on the one hand, the size of the wire feeding tube in the vertical narrow gap direction can be reduced, which facilitates the movement of the wire feeding tube in the gap; on the other hand, it is conducive to accurately feed the wire directly under the tungsten electrode to prevent During the adjustment, due to the axial rotation of the wire feed tube, the welding wire is not accurately positioned in the ultra-narrow gap and deviates from the tungsten electrode.
  • the wire feeding tube needs to be bent into a certain arc to feed the wire into the gap, so the sent wire will also be bent into a certain arc, accurately position the wire feeding tube in the middle of the gap, and keep it on the same plane as the tungsten electrode Above, the stability of the welding process and the shape of the weld can be improved.
  • This example welds SHT490 steel with a thickness of 16mm, an ultra-narrow gap U-groove width of 5mm, and a JQMG70S-6 with a diameter of 1.2mm
  • the carbon steel welding wire, the wire feeding tube and the gun body are mechanically connected, processed into a certain arc and fed into the ultra-narrow gap groove.
  • the mechanical connection can be adjusted as needed to change the direction and position of the wire feeding tube, including the following steps:
  • Adopt 2.4mm tungsten electrode the wire feeding tube extends into the gap from the front end of the gas protection device, the horizontal distance between the wire feeding tube and the tungsten electrode is 5mm, the welding wire extending from the wire feeding tube is located directly below the tungsten electrode, and the tip of the tungsten electrode is perpendicular to the wire
  • the distance is 2.5mm; turn on the welding machine, adjust the welding machine to constant current mode, adjust the welding current to 200A, supply air in advance, delay the air cut; adjust the shielding gas flow to 40L/min; adjust the movement speed of the welding trolley to 100mm/min ;Adjust and set the wire feeding speed of the wire feeding mechanism to 1250mm/min, delay the wire feeding, and draw the wire in advance to prevent the wire from melting into the molten pool in time during the welding process; adjust the PC and set the average motor speed to 5rps.
  • step (2) After the welding of the first layer is completed, use the argon gas delayed from the gas protection device to cool, and then air-cool to about 50°C between layers; then repeat step (2) to weld the next layer; as the number of welded layers increases, Gradually increase the welding current to 230A, and reduce the gas protection to 20L/min, and other parameters remain unchanged.
  • the pulse frequency of the rotating motor is controlled by the PC and the hardware control circuit to control the non-uniform rotation of the rotating tungsten electrode.
  • the heating time of the rotating tungsten electrode on the side wall is 1/2 of the cycle of one rotation. Realize the non-uniform swing of the arc. When the tungsten electrode rotates one circle, about 1/3 of the stage starts to burn on both side walls, and the 2/3 stage of the arc will heat the welding wire and the molten pool in the middle of the gap.
  • the speed of the tungsten electrode tip turning to the sidewalls on both sides is slowed down, and the speed is increased when turning to the middle of the gap, so that during one revolution, the heating time of the sidewall is reduced from the original 1/3 cycle Transform to the current 1/2 cycle.
  • the motor control circuit can be adjusted according to the needs of different gap sizes to adjust the ratio of fast and slow rotation speeds, thereby adjusting the proportion of arc heating time of the side walls.
  • the heat input can be effectively reduced, and on the other hand, the sidewall fusion is more reliable.
  • the arc can be rotated periodically in the ultra-narrow gap groove, periodically heating the welding wire, molten pool and sidewalls, and has a stirring effect on the molten pool; the welding process is stable, the arc burning is stable, and the five layers can complete the 16mmSHT490 steel Welding:
  • the surface of the weld is smooth and bright, showing dense fish-scale features, and the end of the weld is concave, and there is no defect of incomplete sidewall fusion.
  • a welding method suitable for ultra-narrow gap GTAW welding system The steps are as shown in embodiment 12. The difference is that in step (2), the size of the rotating tungsten electrode and the position of the tungsten electrode are adjusted according to the size of the gap: In the horizontal direction of the vertical welding seam, the tungsten electrode is located in the middle of the gap to prevent the tungsten electrode from moving to the side walls of the two sides from momentarily causing a large deviation.
  • the welding gap groove is 6mm, using 3.0mm tungsten electrode, the tip is machined with a 45° inclined surface and has a blunt surface platform, and the height of the tungsten electrode tip from the bottom in the vertical direction is 3.0mm. Adjust the average rotation speed of the motor control tungsten pole to 4rps.
  • a welding method suitable for ultra-narrow gap GTAW welding system The steps are as shown in Example 12. The difference is that in step (2), when the welding gap groove is 4mm, a 2.0mm tungsten electrode is used and the tip is processed It has a 45° inclined surface and has a blunt surface platform. The height of the tungsten electrode tip is 2.0mm from the bottom. Control the average rotation speed of the tungsten electrode to 6rps.
  • a welding method suitable for an ultra-narrow gap GTAW welding system The steps are as shown in Embodiment 12. The difference is that in step (2), the vertical distance between the tip of the rotating tungsten electrode and the welding wire is 2 mm. Ensure the stability of the welding process and uniform weld formation.
  • a welding method suitable for an ultra-narrow gap GTAW welding system The steps are as shown in Embodiment 12. The difference is that in step (2), the vertical distance between the tip of the rotating tungsten electrode and the welding wire is 3 mm. Ensure the stability of the welding process and uniform weld formation.
  • step (3) after the welding of one layer is completed, use shielding gas to cool to the interlayer temperature of 45°C. , And then repeat step (2) to weld the next layer.
  • step (3) After the welding of one layer is completed, it is air-cooled to an interlayer temperature of 55°C with shielding gas , And then repeat step (2) to weld the next layer.
  • a welding method suitable for an ultra-narrow gap GTAW welding system The steps are as shown in Embodiment 12. The difference is that in step (3), the wire feeding speed is 1000 mm/min and the welding speed is 80 mm/min.

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Abstract

一种适用于超窄间隙的GTAW焊接系统，包括氩弧焊焊接电源、TIG焊枪、焊接小车、送丝装置、气保护装置（3）；TIG焊枪包括旋转电机、旋转钨极（6）、导电系统、送气系统，旋转电机通过中心旋转轴带动旋转钨极旋转，旋转钨极为非轴对称钨极，导电系统用于与氩弧焊焊接电源连接并提供电力，送气系统用于向焊枪内提供保护气；TIG焊枪固定设于焊接小车上，由焊接小车带动TIG焊枪移动；送丝装置与焊枪同步移动；气保护装置为壳体，罩于待焊工件上方。还涉及一种焊接方法。该焊接系统和焊接方法适用间隙6mm以下的超窄间隙，焊接过程电弧稳定燃烧、侧壁有效熔合，可以降低热输入，适用全位置焊接，实用性高。

Description

一种适用于超窄间隙的GTAW焊接系统及焊接方法 技术领域
本发明涉及一种适用于超窄间隙的GTAW焊接系统及焊接方法，属于窄间隙焊接技术领域。
背景技术
窄间隙焊接技术是一种在窄间隙坡口中利用全自动焊接装置和电弧控制技术的实现厚板高效率、高质量焊接的方法。窄间隙焊接技术通常应用于低合金钢厚壁容器以及一些重要的合金构件的焊接领域，相比较于传统的焊接方法，窄间隙焊接技术在保证厚板高焊接质量的同时，由于选用小角度坡口，坡口断面面积相对于传统坡口减小50％以上，有效地减少了焊接填充材料的消耗成本，并且可以减少焊接层次，从而有效地减小了工件的焊接应力和变形。
在窄间隙焊接技术的基础上，通过进一步减小间隙尺寸扩大材料成本节省的优势，逐渐发展出了超窄间隙焊接技术，超窄间隙焊接技术是指坡口间隙宽度达到6mm及以下的情况。但是随着坡口宽度的进一步减小，电弧特性变得更加敏感，电弧不稳定，容易出现电弧在侧壁攀爬、在侧壁燃烧以及焊丝回烧的情况。目前研究人员采用焊剂带或焊剂片约束电弧的方法可以在一定程度上解决上述问题，但是存在焊接工艺复杂或者焊接过程稳定性难以保证的问题。而非轴对称旋转钨极窄间隙焊接工艺采用一种非轴对称的钨极，通过钨极在间隙中旋转控制电弧周期性的摆动，结构简单，并且受间隙宽度大小影响程度低，可以有效地解决超窄间隙焊接出现的一些问题。随着板厚的逐渐增加，施焊的难度也随之增加，钨极旋转的同轴度的保证、侧壁的有效熔合、电弧的稳定燃烧以及更深间隙中的气保护问题需要解决。
发明内容
针对现有技术的不足，本发明提供一种适用于超窄间隙的GTAW焊接系统。
本发明还提供利用上述焊接系统的焊接方法。
本发明的技术方案如下：
一种适用于超窄间隙的GTAW焊接系统，包括氩弧焊焊接电源、TIG焊枪、焊接小车、送丝装置、气保护装置；
TIG焊枪包括焊枪枪壳、旋转电机、中心旋转轴、旋转钨极、导电系统、送气系统，旋转电机通过中心旋转轴与旋转钨极相连，旋转钨极为非轴对称钨极，导电系统用于与氩弧焊 焊接电源连接并提供电力，送气系统用于向焊枪内提供保护气；通过旋转电机带动旋转钨极周期性旋转；
TIG焊枪固定设于焊接小车上，由焊接小车带动TIG焊枪移动；
送丝装置与TIG焊枪机械连接，与焊枪同步移动；可以根据需要进行调整送丝角度；全自动送丝装置匹配焊接电源，实现焊接过程中的延时送丝，提前抽丝以及送丝参数的调整等；
所述气保护装置为壳体，壳体罩于待焊工件上方，壳体上设有焊枪口、进气口，TIG焊枪贯穿于焊枪口中，壳体通过进气口连接外界保护气系统。
TIG焊枪的送气系统采用普通TIG焊枪的气保护结构，气体进入焊枪后先充满枪体内气室，经缓冲作用后通过陶瓷喷嘴喷出，对钨极下方的电弧起到一定的拘束作用，保护电弧下方的熔池。
优选的，TIG焊枪前端设有陶瓷喷嘴，陶瓷喷嘴内壁加工出螺旋导气槽。对气流起到一定加速效果，可以使得气体到达坡口更深处。焊接时候，一路氩气通过进气口平缓地进入壳体，散开后形成氩气氛围，对焊后的焊缝区域进行保护，防止出现焊缝氧化的情况。
优选的，TIG焊枪通过螺纹螺栓与焊接小车固定连接。可以通过调节螺纹调节焊枪与工件在水平方向和竖直高度方向的距离。
优选的，TIG焊枪的焊枪枪壳为铝合金材料，减少枪体重量，与夹具接触位置均采用绝缘电木以防止引弧高频对焊枪产生影响。中心旋转轴为黄铜材料，可以减轻焊枪的质量从而有效减小轴向载荷，另一方面，黄铜材料满足力学性能、导热导电性能的同时经济效益高。中心旋转轴与旋转钨极相连处设有电绝缘深沟球轴承，在满足中心旋转轴同轴旋转精度的同时可以有效抵御电流对轴承表面和润滑油的影响，减缓轴承表面腐蚀速度，增加轴承表面的耐磨性，延长轴承的使用寿命。采用机械约束的办法控制钨极的同轴度精度。
优选的，中心旋转轴末端通过反丝紧密螺纹连接旋转钨极。一方面保证良好的气密性，另一方面保证旋转过程中螺纹越转越紧。焊接时，焊枪枪体中流通保护气，加快中心旋转轴、旋转钨极以及导电铜块的散热速度。
优选的，旋转钨极底端设有倾斜面。倾斜面与旋转钨极中心轴之间形成夹角，随着钨极在窄间隙坡口中周期性旋转，钨极尖端与两边侧壁距离发生周期性变化，根据最小电压原理，电弧在窄间隙中随着钨极旋转进行周期性摆动燃烧，有效地熔化焊丝与熔合侧壁。
进一步优选的，倾斜面与旋转钨极中心轴之间的夹角为45°。经对比试验得知，倾斜角度过小时，电弧形态与普通钨极电弧形态相近，无法有效地加热窄间隙两边待焊工件的侧壁，两边侧壁熔合较差；倾斜角度过大时，电弧长度过长，电弧挺度不够，不利于电弧的稳定燃 烧，尖端为45°倾斜角时效果最佳。
进一步优选的，旋转钨极倾斜面尖端设有钝面平台。将钨极尖端加工出平台，一方面可以有效提高电弧的稳定性，另一方面相比较于尖端的钨极，加工出平台可以有效改善使用过程中钨极的烧损情况。
优选的，旋转电机通过联轴器连接中心旋转轴。
优选的，焊接系统还包括PC机、硬件控制电路，旋转电机与PC机相连，通过PC机与硬件控制电路调控电机脉冲频率从而控制旋转钨极的旋转情况。
通过PC机与控制电路控制步进电机的脉冲频率，从而控制步进电机的加速与减速情况。每产生一个脉冲，定时器初值减小一个值，脉冲周期随之减小，脉冲频率随之增大，电机处于加速阶段；当进入减速阶段时，每产生一个脉冲，定时器初值增大一个值，脉冲周期随之增大，脉冲频率随之减小。通过控制电机输出周期性的三角函数波形速度来控制钨极在间隙中的非匀速旋转，使得钨极尖端转动到两边侧壁之时速度达到最慢，转动到间隙中间之时速度最快，从而增大电弧在两边侧壁的停留时间，使得一个电弧摆动周期里更多的热量用来加热两边侧壁。
优选的，壳体为中空方形壳体，焊枪口、气路口设于壳体顶面。
优选的，壳体一端通过滑杆与TIG焊枪相连。壳体沿滑杆可以进行高度的调节并随焊枪同步移动。
优选的，待焊工件下方设有垫板，垫板沿焊缝设有气槽，气槽一端与外界保护气系统相连。除了在带焊工件上方的气保护装置，在待焊工件下方也通入一路保护气，一方面形成氩气氛围对工件背部进行保护，另外一方面可以加速焊件的散热冷却，提高焊接效率。
进一步优选的，垫板为黄铜材料。
优选的，所述送丝装置包括送丝管，送丝管为方形管。不同于常规的圆形管，一方面可以减小送丝管在垂直窄间隙方向的尺寸，便于送丝管在间隙中的运动；另一方面利于准确地将丝送到钨极正下方，防止在调整的时候，由于送丝管的轴向转动而使得焊丝在超窄间隙中定位不准确，偏离钨极。
由于气保护装置的存在，送丝管需要弯成一定弧度将丝送入间隙中，因而送出的丝也会弯成一定弧度，准确将送丝管定位在间隙中间，与钨极保持在同一平面上，可以改善焊接过程的稳定性与焊缝的成形。
一种利用上述适用于超窄间隙的GTAW焊接系统的焊接方法，包括步骤如下：
(1)预处理待焊工件，将待焊工件加工坡口，清理待焊工件；
(2)开启焊接小车，待旋转钨极运动至工件坡口中时，调整旋转钨极位置，使得水平方向上旋转钨极在坡口内居中；送丝管从气保护装置前端伸入间隙中，送丝管伸出的焊丝位于钨极的正下方；开启焊机，调节焊机为恒流模式，提前送气，延时断气；调节设定焊接小车的运动速度；调节设定送丝机构的送丝速度，延时送丝，提前抽丝，防止焊接过程中丝熔化不及时戳入熔池中；调节PC机，设定电机平均转速；
(3)调节好参数后，控制焊接小车运动出坡口，开启旋转电机，使得旋转钨极开始旋转；控制焊接小车运动到坡口边时开启氩弧焊焊接电源，高频引弧进行焊接，送丝管进行送丝；
第一层焊接完成后，利用气保护装置内延后的氩气进行冷却，然后重复步骤(2)进行下一层焊接。
优选的，步骤(2)中，根据间隙尺寸大小调整旋转钨极尺寸和钨极所处位置：垂直焊缝水平方向上，钨极位于间隙正中间位置，防止钨极运动到两边侧壁时刻距离产生较大偏差；
钨极距离底部坡口的高度根据间隙尺寸调整，具体规则如下：焊接6mm间隙坡口时，采用3.0mm钨极，尖端加工出45°倾斜面并且带有钝面平台，钨极尖端距离底部高度3.0mm；焊接5mm间隙坡口时，采用2.4mm钨极，尖端加工出45°倾斜面并且带有钝面平台，钨极尖端距离底部高度2.6mm；焊接4mm间隙坡口时，采用2.0mm钨极，尖端加工出45°倾斜面并且带有钝面平台，钨极尖端距离底部高度2.0mm。
优选的，步骤(2)中，送丝管与旋转钨极的水平间距为5mm。
优选的，步骤(2)中，旋转钨极的尖端距离焊丝的垂直距离为2-3mm。保证焊接过程的稳定性以及焊缝成形均匀。
优选的，步骤(3)中，一层焊接完成后，利用保护气空冷至层间温度45-55℃，然后重复步骤(2)进行下一层焊接。
进一步优选的，步骤(3)中，一层焊接完成后，利用保护气空冷至层间温度50℃，然后重复步骤(2)进行下一层焊接。
优选的，步骤(3)中，下一层焊接过程中，下一层焊接电流较上一层焊接电流增大，下一层保护气流量较上一层保护气流量减小。
优选的，步骤(3)中，通过PC机与硬件控制电路调控旋转电机脉冲频率从而控制旋转钨极非匀速旋转，旋转钨极在侧壁的加热时间为旋转一周周期的1/2。实现电弧的非匀速摆动。钨极旋转一周的过程中，约有1/3的阶段在两边侧壁起弧燃烧，2/3的阶段电弧将在间隙中间加热焊丝以及熔池。通过控制钨极的非匀速旋转，使得钨极尖端转到两边侧壁阶段速度减慢，转到间隙中间时转速加快，从而在旋转一周过程中，侧壁加热时间由原先的1/3个周期转变 为现在的1/2个周期。
并且可以根据不同间隙大小的需要调节电机控制电路来调节快慢转动速度之比，从而调节电弧加热侧壁时间的占比，一方面可以有效地减少热输入，另外一方面侧壁熔合更加可靠。
进一步优选的，步骤(2)中，随着间隙的减小，为了在保证两边侧壁熔合良好、焊丝及时熔化的同时又不会热输入过大，需要增大焊接速度与钨极旋转的速度，具体规律如下：焊接6mm间隙坡口时，调整电机控制钨极平均转动速度为4rps；焊接5mm间隙坡口时，控制钨极平均转动速度为5rps；焊接4mm间隙坡口时，控制钨极平均转动速度为6rps。根据不同尺寸来调整钨极转动的平均速度，化解了热输入过大与熔合不好之间平衡的矛盾。
优选的，步骤(3)中，送丝速度、焊接速度与热输入之间存在匹配关系，送丝速度调整区间为1000mm/min-1250mm/min、根据需要调整，焊接速度调整区间80mm/min-100mm/min，通过调整焊接电流与焊接速度控制焊接热输入在2.0-2.5kJ/mm区间内，防止出现送丝过快熔化不及时导致丝戳入熔池中，影响焊接过程的稳定性以及送丝速度过小熔覆金属不足的情况。
本发明的有益效果在于：
本发明的技术方案通过加工4-6mm超窄间隙U型坡口实现厚板、大厚板的焊接，相比较于窄间隙焊接进一步扩大了原料节省方面的优势，有效地减小了坡口加工面积，增大了熔敷金属的填充效率，在减小了热输入的同时提高了焊接效率。
本发明的技术方案通过周期性调控钨极转速来合理调节电弧在超窄间隙中各区域的停留时间，从而调节不同位置的热量分配，使得一个旋转周期中电弧有更多的时间加热侧壁，确保两边侧壁的有效熔合。
本发明的技术方案通过设置三路气保护，气保护装置内提前通入保护气形成保护气氛，垫板气槽通气形成保护气氛环境，中间气路通过TIG焊枪的陶瓷喷嘴内壁导气槽螺旋加速后送入到超窄间隙中，有效解决了超窄间隙中保护气无法有效送达间隙底端的问题，保证了电弧在超窄间隙中的稳定燃烧。
本发明的技术方案通过将钨极加工出带平台的非轴对称尖端，在实现了电弧在超窄间隙中周期性摇摆稳定燃烧的同时减缓了钨极尖端的烧损；通过加工特定形状的送丝机构，准确将焊丝定位在超窄间隙中，可以实现厚板的稳定送丝。
本发明的技术方案通过焊接小车带动焊枪移动，通过焊枪位置调节装置可以实现焊枪与钨极在各个方向上的精确定位，确保焊接过程的稳定进行，根据不同间隙优化参数，可以实现厚板高质量高效率的全位置焊接，实用性高。
附图说明
图1本发明的气保护装置示意图；
图2本发明的非轴对称钨极示意图；
图3本发明的送丝管示意图；
上述图中，1、进气口；2、焊枪口；3、气保护装置；4、垫板；5、气槽；6、旋转钨极；7、倾斜面；8、钝面平台。
具体实施方式
下面通过实施例并结合附图对本发明做进一步说明，但不限于此。
实施例1：
一种适用于超窄间隙的GTAW焊接系统，包括氩弧焊焊接电源、TIG焊枪、焊接小车、送丝装置、气保护装置。
TIG焊枪包括焊枪枪壳、旋转电机、中心旋转轴、旋转钨极、导电系统、送气系统，旋转电机通过中心旋转轴与旋转钨极相连，旋转钨极为非轴对称钨极，导电系统用于与氩弧焊焊接电源连接并提供电力，送气系统用于向焊枪内提供保护气；通过旋转电机带动旋转钨极周期性旋转。
TIG焊枪固定设于焊接小车上，由焊接小车带动TIG焊枪移动。
送丝装置与TIG焊枪机械连接，与焊枪同步移动；可以根据需要进行调整送丝角度；全自动送丝装置匹配焊接电源，实现焊接过程中的延时送丝，提前抽丝以及送丝参数的调整等。
所述气保护装置为壳体，壳体罩于待焊工件上方，壳体上设有焊枪口、进气口，如图1所示，TIG焊枪贯穿于焊枪口中，壳体通过进气口连接外界保护气系统。
TIG焊枪的送气系统采用普通TIG焊枪的气保护结构，气体进入焊枪后先充满枪体内气室，经缓冲作用后通过陶瓷喷嘴喷出，对钨极下方的电弧起到一定的拘束作用，保护电弧下方的熔池。
TIG焊枪前端设有陶瓷喷嘴，陶瓷喷嘴内壁加工出螺旋导气槽，对气流起到一定加速效果，可以使得气体到达坡口更深处。焊接时候，一路氩气通过进气口平缓地进入壳体，散开后形成氩气氛围，对焊后的焊缝区域进行保护，防止出现焊缝氧化的情况。
TIG焊枪的焊枪枪壳为铝合金材料，减少枪体重量，与夹具接触位置均采用绝缘电木以防止引弧高频对焊枪产生影响。中心旋转轴为黄铜材料，可以减轻焊枪的质量从而有效减小轴向载荷，另一方面，黄铜材料满足力学性能、导热导电性能的同时经济效益高。中心旋转轴与旋转钨极相连处设有电绝缘深沟球轴承，在满足中心旋转轴同轴旋转精度的同时可以有效抵御电流对轴承表面和润滑油的影响，减缓轴承表面腐蚀速度，增加轴承表面的耐磨性， 延长轴承的使用寿命。采用机械约束的办法控制钨极的同轴度精度。
实施例2：
一种适用于超窄间隙的GTAW焊接系统，其结构如实施例1所述，所不同的是，TIG焊枪通过螺纹螺栓与焊接小车固定连接。可以通过调节螺纹调节焊枪与工件在水平方向和竖直高度方向的距离。
实施例3：
一种适用于超窄间隙的GTAW焊接系统，其结构如实施例1所述，所不同的是，中心旋转轴末端通过反丝紧密螺纹连接旋转钨极。一方面保证良好的气密性，另一方面保证旋转过程中螺纹越转越紧。焊接时，焊枪枪体中流通保护气，加快中心旋转轴、旋转钨极以及导电铜块的散热速度。
实施例4：
一种适用于超窄间隙的GTAW焊接系统，其结构如实施例1所述，所不同的是，旋转钨极底端设有倾斜面，旋转钨极倾斜面尖端设有钝面平台，如图2所示。倾斜面与旋转钨极中心轴之间形成夹角，随着钨极在窄间隙坡口中周期性旋转，钨极尖端与两边侧壁距离发生周期性变化，根据最小电压原理，电弧在窄间隙中随着钨极旋转进行周期性摆动燃烧，有效地熔化焊丝与熔合侧壁。将钨极尖端加工出平台，一方面可以有效提高电弧的稳定性，另一方面相比较于尖端的钨极，加工出平台可以有效改善使用过程中钨极的烧损情况。
实施例5：
一种适用于超窄间隙的GTAW焊接系统，其结构如实施例4所述，所不同的是，倾斜面与旋转钨极中心轴之间的夹角为45°。经对比试验得知，倾斜角度过小时，电弧形态与普通钨极电弧形态相近，无法有效地加热窄间隙两边待焊工件的侧壁，两边侧壁熔合较差；倾斜角度过大时，电弧长度过长，电弧挺度不够，不利于电弧的稳定燃烧，尖端为45°倾斜角时效果最佳。
实施例6：
一种适用于超窄间隙的GTAW焊接系统，其结构如实施例1所述，所不同的是，旋转电机通过联轴器连接中心旋转轴。
实施例7：
一种适用于超窄间隙的GTAW焊接系统，其结构如实施例5所述，所不同的是，焊接系统还包括PC机、硬件控制电路，旋转电机与PC机相连，通过PC机与硬件控制电路调控电机脉冲频率从而控制旋转钨极的旋转情况。
通过PC机与控制电路控制步进电机的脉冲频率，从而控制步进电机的加速与减速情况。每产生一个脉冲，定时器初值减小一个值，脉冲周期随之减小，脉冲频率随之增大，电机处于加速阶段；当进入减速阶段时，每产生一个脉冲，定时器初值增大一个值，脉冲周期随之增大，脉冲频率随之减小。通过控制电机输出周期性的三角函数波形速度来控制钨极在间隙中的非匀速旋转，使得钨极尖端转动到两边侧壁之时速度达到最慢，转动到间隙中间之时速度最快，从而增大电弧在两边侧壁的停留时间，使得一个电弧摆动周期里更多的热量用来加热两边侧壁。
实施例8：
一种适用于超窄间隙的GTAW焊接系统，其结构如实施例1所述，所不同的是，壳体为中空方形壳体，焊枪口、气路口设于壳体顶面。
实施例9：
一种适用于超窄间隙的GTAW焊接系统，其结构如实施例1所述，所不同的是，壳体一端通过滑杆与TIG焊枪相连。壳体沿滑杆可以进行高度的调节并随焊枪同步移动。
实施例10：
一种适用于超窄间隙的GTAW焊接系统，其结构如实施例7所述，所不同的是，待焊工件下方设有垫板，垫板沿焊缝设有气槽，气槽一端与外界保护气系统相连。除了在待焊工件上方的气保护装置，在待焊工件下方也通入一路保护气，一方面形成氩气氛围对工件背部进行保护，另外一方面可以加速焊件的散热冷却，提高焊接效率。垫板为黄铜材料。
实施例11：
一种适用于超窄间隙的GTAW焊接系统，其结构如实施例10所述，所不同的是，所述送丝装置包括送丝管，送丝管为方形管。不同于常规的圆形管，一方面可以减小送丝管在垂直窄间隙方向的尺寸，便于送丝管在间隙中的运动；另一方面利于准确地将丝送到钨极正下方，防止在调整的时候，由于送丝管的轴向转动而使得焊丝在超窄间隙中定位不准确，偏离钨极。
由于气保护装置的存在，送丝管需要弯成一定弧度将丝送入间隙中，因而送出的丝也会弯成一定弧度，准确将送丝管定位在间隙中间，与钨极保持在同一平面上，可以改善焊接过程的稳定性与焊缝的成形。
实施例12：
一种利用实施例11所述适用于超窄间隙的GTAW焊接系统的焊接方法，本实例焊接厚度为16mm的SHT490钢，超窄间隙U型坡口宽度5mm，采用直径为1.2mm的JQMG70S-6 碳钢焊丝，送丝管与枪体为机械连接，加工成一定弧度送入到超窄间隙坡口中，可以根据需要调整机械连接改变送丝管的方向与位置，包括步骤如下：
(1)预处理待焊工件，16mmSHT490钢开坡口，坡口利用线切割加工，U型坡口宽度为5mm，深度为14mm，背部留2mm钝边，底部连接处为半径1mm的圆角。焊接操作之前，利用角磨机、砂纸以及酒精清理钢板及坡口内的油污与铁锈。清理完毕后，利用夹具固定钢板，并设置4-5°的预变形角度来抵消焊接过程中工件的变形。
(2)开启焊接小车，待旋转钨极运动至工件坡口中时，调整旋转钨极位置，使得水平方向上旋转钨极在坡口内居中，竖直方向上钨极尖端距离底部坡口2.6mm，采用2.4mm钨极；送丝管从气保护装置前端伸入间隙中，送丝管与钨极水平间距5mm，送丝管伸出的焊丝位于钨极的正下方，钨极尖端到丝的垂直距离2.5mm；开启焊机，调节焊机为恒流模式，调节焊接电流为200A，提前送气，延时断气；保护气流量调节为40L/min；调节设定焊接小车的运动速度为100mm/min；调节设定送丝机构的送丝速度为1250mm/min，延时送丝，提前抽丝，防止焊接过程中丝熔化不及时戳入熔池中；调节PC机，设定电机平均转速5rps。
(3)调节好参数后，控制焊接小车运动出坡口，开启旋转电机，使得旋转钨极开始旋转；控制焊接小车运动到坡口边时开启氩弧焊焊接电源，高频引弧进行焊接，送丝管进行送丝；
第一层焊接完成后，利用气保护装置内延后的氩气进行冷却，而后空冷至层间温度50℃左右；然后重复步骤(2)进行下一层焊接；随着焊接层数的增加，逐渐增大焊接电流至230A，并且减小气保护至20L/min，其他参数保持不变。
通过PC机与硬件控制电路调控旋转电机脉冲频率从而控制旋转钨极非匀速旋转，旋转钨极在侧壁的加热时间为旋转一周周期的1/2。实现电弧的非匀速摆动。钨极旋转一周的过程中，约有1/3的阶段在两边侧壁起弧燃烧，2/3的阶段电弧将在间隙中间加热焊丝以及熔池。通过控制钨极的非匀速旋转，使得钨极尖端转到两边侧壁阶段速度减慢，转到间隙中间时转速加快，从而在旋转一周过程中，侧壁加热时间由原先的1/3个周期转变为现在的1/2个周期。
并且可以根据不同间隙大小的需要调节电机控制电路来调节快慢转动速度之比，从而调节电弧加热侧壁时间的占比，一方面可以有效地减少热输入，另外一方面侧壁熔合更加可靠。
本实例可以做到电弧在超窄间隙坡口中周期性旋转，周期性加热焊丝、熔池以及侧壁，并且对熔池具有搅拌作用；焊接过程稳定，电弧燃烧平稳，五层可以完成16mmSHT490钢的焊接；焊缝表面平整光亮，呈现致密的鱼鳞纹特征，焊缝端面呈现下凹状，没有侧壁熔合不完全的缺陷产生。
实施例13：
一种适用于超窄间隙的GTAW焊接系统的焊接方法，步骤如实施例12所示，所不同的是，步骤(2)中，根据间隙尺寸大小调整旋转钨极尺寸和钨极所处位置：垂直焊缝水平方向上，钨极位于间隙正中间位置，防止钨极运动到两边侧壁时刻距离产生较大偏差。
焊接间隙坡口为6mm，采用3.0mm钨极，尖端加工出45°倾斜面并且带有钝面平台，竖直方向上钨极尖端距离底部高度3.0mm。调整电机控制钨极平均转动速度为4rps。
实施例14：
一种适用于超窄间隙的GTAW焊接系统的焊接方法，步骤如实施例12所示，所不同的是，步骤(2)中，焊接间隙坡口为4mm时，采用2.0mm钨极，尖端加工出45°倾斜面并且带有钝面平台，钨极尖端距离底部高度2.0mm。控制钨极平均转动速度为6rps。
实施例15：
一种适用于超窄间隙的GTAW焊接系统的焊接方法，步骤如实施例12所示，所不同的是，步骤(2)中，旋转钨极的尖端距离焊丝的垂直距离为2mm。保证焊接过程的稳定性以及焊缝成形均匀。
实施例16：
一种适用于超窄间隙的GTAW焊接系统的焊接方法，步骤如实施例12所示，所不同的是，步骤(2)中，旋转钨极的尖端距离焊丝的垂直距离为3mm。保证焊接过程的稳定性以及焊缝成形均匀。
实施例17：
一种适用于超窄间隙的GTAW焊接系统的焊接方法，步骤如实施例12所示，所不同的是，步骤(3)中，一层焊接完成后，利用保护气空冷至层间温度45℃，然后重复步骤(2)进行下一层焊接。
实施例18：
一种适用于超窄间隙的GTAW焊接系统的焊接方法，步骤如实施例12所示，所不同的是，步骤(3)中，一层焊接完成后，利用保护气空冷至层间温度55℃，然后重复步骤(2)进行下一层焊接。
实施例19：
一种适用于超窄间隙的GTAW焊接系统的焊接方法，步骤如实施例12所示，所不同的是，步骤(3)中，送丝速度为1000mm/min，焊接速度80mm/min。

Claims (10)

  1. 一种适用于超窄间隙的GTAW焊接系统，其特征在于，包括氩弧焊焊接电源、TIG焊枪、焊接小车、送丝装置、气保护装置；
    TIG焊枪包括焊枪枪壳、旋转电机、中心旋转轴、旋转钨极、导电系统、送气系统，旋转电机通过中心旋转轴与旋转钨极相连，旋转钨极为非轴对称钨极，导电系统用于与氩弧焊焊接电源连接并提供电力，送气系统用于向焊枪内提供保护气；
    TIG焊枪固定设于焊接小车上，由焊接小车带动TIG焊枪移动；
    送丝装置与TIG焊枪机械连接；
    所述气保护装置为壳体，壳体罩于待焊工件上方，壳体上设有焊枪口、进气口，TIG焊枪贯穿于焊枪口中，壳体通过进气口连接外界保护气系统。
  2. 根据权利要求1所述的适用于超窄间隙的GTAW焊接系统，其特征在于，TIG焊枪通过螺纹螺栓与焊接小车固定连接；中心旋转轴末端通过反丝紧密螺纹连接旋转钨极；旋转电机通过联轴器连接中心旋转轴；
    TIG焊枪前端设有陶瓷喷嘴，陶瓷喷嘴内壁设有螺旋导气槽。
  3. 根据权利要求1所述的适用于超窄间隙的GTAW焊接系统，其特征在于，旋转钨极底端设有倾斜面；
    优选的，旋转钨极倾斜面尖端设有钝面平台；
    进一步优选的，倾斜面与旋转钨极中心轴之间的夹角为45°。
  4. 根据权利要求1所述的适用于超窄间隙的GTAW焊接系统，其特征在于，焊接系统还包括PC机、硬件控制电路，旋转电机与PC机相连，通过PC机与硬件控制电路调控电机脉冲频率从而控制旋转钨极的旋转情况；
    优选的，所述送丝装置包括送丝管，送丝管为方形管。
  5. 根据权利要求1所述的适用于超窄间隙的GTAW焊接系统，其特征在于，壳体为中空方形壳体，焊枪口、气路口设于壳体顶面；
    优选的，壳体一端通过滑杆与TIG焊枪相连。
  6. 根据权利要求1所述的适用于超窄间隙的GTAW焊接系统，其特征在于，待焊工件下方设有垫板，垫板沿焊缝设有气槽，气槽一端与外界保护气系统相连；
    优选的，垫板为黄铜材料。
  7. 一种利用权利要求1-6任意一项权利要求所述适用于超窄间隙的GTAW焊接系统的 焊接方法，其特征在于，包括步骤如下：
    (1)预处理待焊工件，将待焊工件开坡口，清理待焊工件；
    (2)开启焊接小车，待旋转钨极运动至工件坡口中时，调整旋转钨极位置，使得水平方向上旋转钨极在坡口内居中；送丝管从气保护装置前端伸入间隙中，送丝管伸出的焊丝位于钨极的正下方；开启焊机，调节焊机为恒流模式，提前送气，延时断气；调节设定焊接小车的运动速度；调节设定送丝机构的送丝速度，延时送丝，提前抽丝；调节PC机，设定电机平均转速；
    (3)调节好参数后，控制焊接小车运动出坡口，开启旋转电机，使得旋转钨极开始旋转；控制焊接小车运动到坡口边时开启氩弧焊焊接电源，高频引弧进行焊接，送丝管进行送丝；
    第一层焊接完成后，利用气保护装置内延后的氩气进行冷却，然后重复步骤(2)进行下一层焊接。
  8. 根据权利要求7所述的适用于超窄间隙的GTAW焊接系统的焊接方法，其特征在于，步骤(2)中，根据间隙尺寸大小调整旋转钨极尺寸和钨极所处位置：垂直焊缝水平方向上，钨极位于间隙正中间位置；
    钨极距离底部坡口的高度根据间隙尺寸调整：焊接6mm间隙坡口时，采用3.0mm钨极，尖端加工出45°倾斜面并且带有钝面平台，钨极尖端距离底部高度3.0mm；焊接5mm间隙坡口时，采用2.4mm钨极，尖端加工出45°倾斜面并且带有钝面平台，钨极尖端距离底部高度2.6mm；焊接4mm间隙坡口时，采用2.0mm钨极，尖端加工出45°倾斜面并且带有钝面平台，钨极尖端距离底部高度2.0mm；
    优选的，步骤(2)中，送丝管与旋转钨极的水平间距为5mm，旋转钨极的尖端距离焊丝的垂直距离为2-3mm；
    进一步优选的，步骤(2)中，焊接6mm间隙坡口时，调整电机控制钨极平均转动速度为4rps；焊接5mm间隙坡口时，控制钨极平均转动速度为5rps；焊接4mm间隙坡口时，控制钨极平均转动速度为6rps。
  9. 根据权利要求7所述的适用于超窄间隙的GTAW焊接系统的焊接方法，其特征在于，步骤(3)中，一层焊接完成后，利用保护气空冷至层间温度45-55℃，然后重复步骤(2)进行下一层焊接；
    优选的，步骤(3)中，一层焊接完成后，利用保护气空冷至层间温度50℃，然后重复步骤(2)进行下一层焊接；
    进一步优选的，步骤(3)中，下一层焊接过程中，下一层焊接电流较上一层焊接电流增 大，下一层保护气流量较上一层保护气流量减小。
  10. 根据权利要求7所述的适用于超窄间隙的GTAW焊接系统的焊接方法，其特征在于，步骤(3)中，通过PC机与硬件控制电路调控旋转电机脉冲频率从而控制旋转钨极非匀速旋转，旋转钨极在侧壁的加热时间为旋转一周周期的1/2；
    优选的，步骤(3)中，送丝速度、焊接速度与热输入之间存在匹配关系，送丝速度调整区间为1000mm/min-1250mm/min，焊接速度调整区间80mm/min-100mm/min，通过调整焊接电流与焊接速度控制焊接热输入在2.0-2.5kJ/mm区间内。
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CN113814619B (zh) * 2021-10-28 2024-02-23 经典重工集团股份有限公司 一种窄间隙焊接装置
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