Long-distance pipeline high-speed automatic argon arc welding root welding method

Abstract

The application discloses a long pipeline high-speed automatic argon arc root welding method, which comprises the following steps: S1, welding preparation; S2, cleaning; S3, groove preheating; S4, aligning; S5, installing equipment; S6, welding; S7, filling and covering; and S8, information collection and preservation. The automatic welding gun is adopted, a high-low frequency cyclic double-pulse current is generated by using a control system, and mature control parameters are used, so that the reliability of pipeline backing welding is further improved, the root welding speed is increased to a maximum of 250 mm / min, the efficiency is greatly improved, meanwhile, the welding parameters during operation are recorded synchronously, and are archived and preserved, so that convenience is provided for subsequent research and use.

Description

Technical Field

[0001] This invention belongs to the field of welding technology for long-distance pipelines, and specifically relates to a high-speed automatic argon arc welding root welding method for long-distance pipelines. Background Technology

[0002] Argon arc welding is a welding technique based on the principle of ordinary electric arc welding. It utilizes argon gas to protect the metal welding material and uses high current to melt the welding material into a liquid state on the substrate to form a molten pool, thus achieving a metallurgical bond between the welded metal and the welding material. Because argon gas is continuously supplied during high-temperature molten welding, the welding material cannot come into contact with oxygen in the air, thereby preventing oxidation of the welding material. Therefore, it can weld stainless steel, carbon steel and other metals.

[0003] Currently, argon arc welding is generally done manually at a speed of 60-80 mm / min. While manual welding can achieve certain results, it is extremely slow in pipe welding, especially for large-diameter or long pipes. Increasing the speed directly would reduce the filler volume, cause uneven stress on the weld, and reduce the steel's performance. Furthermore, to ensure a sufficiently fast melting rate, the current needs to be increased due to the increased speed, which would make it very easy to burn through the base material. Therefore, it takes a skilled welder about 2 hours to weld a compliant 1.2-meter diameter pipe, which is very inefficient. Moreover, the quality of the weld depends on the welder's experience and skills. In addition, manual argon arc welding cannot collect welding parameters such as welding speed, wire feed speed, and oscillation parameters, and it is impossible to collect information and send it to a designated server for research and storage. Summary of the Invention

[0004] The purpose of this invention is to provide a high-speed automatic argon arc welding root welding method for long-distance pipelines, which solves the problems of low efficiency and inability to collect relevant welding parameters in current manual welding of large-diameter long pipelines.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A high-speed automatic argon arc welding root welding method for long-distance pipelines includes the following steps:

[0007] S1) Preparation before welding: Load the tungsten electrode into the welding gun, feed the welding wire a certain distance outside the contact tip, cut off the bent part, adjust the distance between the welding wire and the tungsten electrode to 1.5-2.5mm, and adjust the gas flow rate to 10-20L / min;

[0008] S2) Cleaning: Cut and grind the welding bevel before welding, using a U-shaped bevel, and clean the oxides and oil stains within 20mm on both sides of the bevel to expose the metal color;

[0009] S3) Bevel preheating: Preheat the pipe openings on both sides of the bevel to 100-150℃ using fire or electric heating equipment;

[0010] S4) Alignment: Use an internal or external alignment tool to align the two pipe ends tightly, ensuring the alignment gap is ≤0.5mm and the misalignment is ≤2mm;

[0011] S5) Equipment Installation: Install the automatic welding gun, adjust the distance between the tungsten electrode and the workpiece to 1.5-2.5mm, and connect the high-frequency and low-frequency dual-pulse power supply. Set the high-frequency pulse frequency to 500-15000Hz.

[0012] S6) Welding: Downward welding is adopted, with segmented parameter control. The welding speed of the automatic welding gun is 100-250mm / min, and the voltage is 8-15V. Welding is performed according to the following parameters based on different angles;

[0013] 0°-40°: Peak current: 170-320A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V

[0014] 40°-120°: Peak current: 160-315A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V

[0015] 120°-150°: Peak current: 160-315A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V

[0016] 150°-180°: Peak current: 160-310A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V

[0017] S7), matching filler, capping: downhill welding, wire extension 8-14mm, single layer welding thickness 2-3mm, capping uses two passes of welding, swing speed is 1.5M / min, welding parameters are as follows:

[0018] 0°-20°: Wire feed speed: 280-330 IPM; Welding speed: 350-480 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3-7 mm; Dwell time: 0.05-0.15 s; Voltage: 19-26 V

[0019] 20°-120°: Wire feed speed: 290-350 IPM; Welding speed: 380-520 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3-7 mm; Dwell time: 0.05-0.15 s; Voltage: 19-26 V

[0020] 120°-140°: Wire feed speed: 240-320 IPM; Welding speed: 330-440 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3.2-7.2 mm; Dwell time: 0.1-0.2 s; Voltage: 18.5-25 V

[0021] 140°-160°: Wire feed speed: 210-290 IPM; Welding speed: 290-380 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3.4-7.4 mm; Dwell time: 0.15-0.25 s; Voltage: 18-24 V

[0022] 160°-180°: Wire feed speed: 180-250 IPM; Welding speed: 250-330 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3.6-7.6 mm; Dwell time: 0.25-0.4 s; Voltage: 18-23 V

[0023] S8) Information collection and storage: Record and store the data from the equipment operation on the server for subsequent analysis;

[0024] Furthermore, the high- and low-frequency dual-pulse power supply uses a fully automatic tungsten inert gas welding power supply with high- and low-frequency cyclic output function. The control system can make the power supply work at one working point for a certain period of time, then switch to another working point, and then work for a certain period of time before returning to the previous working point, switching cyclically.

[0025] Furthermore, the switching frequency is 0.2-10Hz. One working point is responsible for melting through the blunt edge, while the other working point is used to cool the molten pool while maintaining the arc. At both working points, the welding current is superimposed with high and low frequency pulses, with a pulse frequency of 500-15000Hz. The base current of the high and low frequency pulses is 50-150% of the given current.

[0026] Furthermore, the root weld thickness is 3-3.5mm.

[0027] Furthermore, a dedicated argon arc welding wire with a diameter of 1.0 mm and a tungsten electrode with a diameter of 3.2 mm or 4.0 mm are used for welding.

[0028] Furthermore, 1.2mm solid welding wire is used for the filler and cover, with a welding current of 150-280A.

[0029] In other words, the testing items include RT testing, AUT testing, and mechanical property testing.

[0030] The beneficial effects of this invention are:

[0031] This invention employs an automatic welding torch and utilizes a control system to generate high- and low-frequency cyclic dual-pulse currents. The use of mature control parameters further improves the reliability of pipe root pass welding, increasing the root pass welding speed to a maximum of 250 mm / min. Due to the reduced filler volume, the time to complete the entire weld bead is reduced by 2 / 3 compared to the time using a conventional V-shaped nozzle, resulting in a significant increase in efficiency. Simultaneously, the welding parameters are recorded and archived, providing convenience for subsequent research and use.

[0032] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the bevel style;

[0034] Figure 2 This is a schematic diagram of the welded layers;

[0035] Figure 3 The waveform diagram shows the root welding current and wire feed speed.

[0036] Figure 4 This is a diagram illustrating the switching between two working points;

[0037] Figure 5 This is a flowchart of the steps of the present invention;

[0038] The parts in the attached diagram are labeled as follows:

[0039] 1. Bevel angle; 2. Bevel fillet; 3. Blunt edge extension length; 4. Blunt edge; 5. Molten pool; 6. Current waveform; 7. Wire feed speed waveform; 8. First operating point of welding power source; 9. Second operating point of welding power source. Detailed Implementation

[0040] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention. Specific Implementation

[0041] A high-speed automatic argon arc welding root welding method for long-distance pipelines includes the following steps:

[0042] S1) Preparation before welding: Load the tungsten electrode into the welding gun, feed the welding wire a certain distance outside the contact tip, cut off the bent part, adjust the distance between the welding wire and the tungsten electrode to 1.5-2.5mm, and adjust the gas flow rate to 10-20L / min;

[0043] S2) Cleaning: Cut and grind the welding bevel before welding, using a U-shaped bevel, and clean the oxides and oil stains within 20mm on both sides of the bevel to expose the metal color;

[0044] S3) Bevel preheating: Preheat the pipe openings on both sides of the bevel to 100-150℃ using fire or electric heating equipment;

[0045] S4) Alignment: Use an internal or external alignment tool to align the two pipe ends tightly, ensuring the alignment gap is ≤0.5mm and the misalignment is ≤2mm;

[0046] S5) Equipment Installation: Install the automatic welding gun, adjust the distance between the tungsten electrode and the workpiece to 1.5-2.5mm, and connect the high- and low-frequency dual-pulse power supply, setting the pulse frequency to 500-15000Hz;

[0047] S6) Welding: Downward welding is adopted, with segmented parameter control. The welding speed of the automatic welding gun is 100-250mm / min, and the voltage is 8-15V. Welding is carried out according to the following parameters based on different angles: 0° is the position directly above the pipe, and 180° is the position directly below the pipe.

[0048] 0°-40°: Peak current: 170-320A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V

[0049] 40°-120°: Peak current: 160-315A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V

[0050] 120°-150°: Peak current: 160-315A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V

[0051] 150°-180°: Peak current: 160-310A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V

[0052] S7), matching filler, capping: downhill welding, wire extension 8-14mm, single layer welding thickness 2-3mm, capping uses two passes of welding, swing speed is 1.5M / min, welding parameters are as follows:

[0053] 0°-20°: Wire feed speed: 280-330 IPM; Welding speed: 350-480 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3-7 mm; Dwell time: 0.05-0.15 s; Voltage: 19-26 V

[0054] 20°-120°: Wire feed speed: 290-350 IPM; Welding speed: 380-520 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3-7 mm; Dwell time: 0.05-0.15 s; Voltage: 19-26 V

[0055] 120°-140°: Wire feed speed: 270-320 IPM; Welding speed: 330-440 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3.2-7.2 mm; Dwell time: 0.1-0.2 s; Voltage: 18.5-25 V

[0056] 140°-160°: Wire feed speed: 240-290 IPM; Welding speed: 290-380 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3.4-7.4 mm; Dwell time: 0.15-0.25 s; Voltage: 18-24 V

[0057] 160°-180°: Wire feed speed: 200-250 IPM; Welding speed: 250-330 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3.6-7.6 mm; Dwell time: 0.25-0.4 s; Voltage: 18-23 V

[0058] S8) Information collection and storage: Record and store the data of the equipment operation in the equipment memory or upload it to the server for subsequent analysis and use. The high and low frequency dual pulse power supply uses a fully automatic tungsten inert gas welding power supply with high and low frequency cyclic output function. The control system can make the power supply work at one working point for a certain period of time, then switch to another working point, and then work for a certain period of time before returning to the previous working point, and switch cyclically.

[0059] Specifically, using a pulsed TIG welding power supply capable of outputting both high and low frequency pulses, along with its matching control system, can output the following: Figure 3 The current waveform shown (it should be noted that due to the different inductance of the welding circuit, the rising and falling edges of the output pulse current waveform will have a certain slope, especially the high-frequency pulse waveform may not be a pure square wave), the wire feed speed can follow the changes of the low-frequency current pulse, the switching frequency is 0.2-10Hz, one working point is responsible for penetrating the blunt edge, and the other working point is used to cool the molten pool while maintaining the arc. At both working points, the welding current is superimposed with a high-frequency pulse, the pulse frequency is 500-15000Hz, and the base current of the high-frequency pulse is 50-150% of the given current (see attached figure). Figure 3 P1 is the first operating point of the welding power source, P2 is the second operating point of the welding power source, I1 is the current at the first operating point, u1 is the voltage at the first operating point, I2 is the current at the second operating point, u2 is the voltage at the second operating point, I3 is the base current of the high-frequency pulse superimposed on the current at the first operating point, I4 is the base current of the high-frequency pulse superimposed on the current at the second operating point, v1 is the wire feed speed at the first operating point, v2 is the wire feed speed at the second operating point, T1 is the duration of the first operating point, and T2 is the duration of the second operating point.

[0060] Specifically, the root weld thickness is 3-3.5mm.

[0061] Specifically, a special argon arc welding wire with a diameter of 1.0 mm is used, along with a cerium-tungsten electrode with a diameter of 3.2 mm or 4.0 mm.

[0062] Specifically, 1.2mm solid welding wire is used for filling and covering, and the welding current is 200-280A.

[0063] Specifically, the testing is conducted in accordance with the GB / T 31032-2014 standard, and the testing items include RT testing, AUT testing, and mechanical property testing.

[0064] Inspection results show that the weld appearance is uniform and consistent, with no defects such as cracks, porosity, slag inclusions, or depressions on the weld surface. The cap width is 0.5-2 mm wider on each side than the bevel width, and the weld reinforcement is between 0-2 mm, with no undercut. RT and AUT tests were performed, and both met the standard requirements. Mechanical property tests, including transverse tensile tests, longitudinal tensile tests, back bending tests, side bending tests, grooved hammer fracture tests, macroscopic metallography, low-temperature impact toughness tests, and hardness tests, all met the requirements of GB / T 31032-2014 standard.

[0065] Specifically, argon gas with a purity of not less than 99.99% is used as a protective gas.

[0066] The principle of this invention is as follows:

[0067] Because the control system can switch between two working points in a cycle, with a switching frequency of 0.2-10Hz, one working point is responsible for melting the blunt edge, while the other working point is used to cool the molten pool while maintaining the arc. At the two working points, the welding current is superimposed with a high-frequency double pulse current, and the high-frequency pulse can further shrink the arc, so the heat is more concentrated, the melting is more reliable, and it is less likely to produce burn-through defects. Therefore, the welding speed can be further increased to a maximum of 250mm / min.

[0068] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A high-speed automatic argon arc welding root welding method for long-distance pipelines, characterized in that... It includes the following steps: S1) Preparation before welding: Load the tungsten electrode into the welding gun, feed the welding wire a certain distance outside the contact tip, cut off the bent part, adjust the distance between the welding wire and the tungsten electrode to 1.5-2.5mm, and adjust the gas flow rate to 10-20L / min; S2) Cleaning: Cut and grind the welding bevel before welding, using a U-shaped bevel, and clean the oxides and oil stains within 20mm on both sides of the bevel to expose the metal color; S3) Bevel preheating: Preheat the pipe openings on both sides of the bevel to 100-150℃ using fire or electric heating equipment; S4) Alignment: Use an internal or external alignment tool to align the two pipe ends tightly, ensuring the alignment gap is ≤0.5mm and the misalignment is ≤2mm; S5) Equipment Installation: Install the automatic welding gun, adjust the distance between the tungsten electrode and the workpiece to 1.5-2.5mm, and connect the high- and low-frequency dual-pulse power supply; S6) Welding: Downward welding is adopted, with segmented parameter control. The welding speed of the automatic welding gun is 100-250mm / min, and the voltage is 8-15V. Welding is performed according to the following parameters based on different angles; 0°-40°: Peak current: 170-320A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V 40°-120°: Peak current: 160-315A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V 120°-150°: Peak current: 160-315A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V 150°-180°: Peak current: 160-310A; Peak wire feed: 80-180 IPM; Peak time: 0.2-0.5S; Base current: 20-60% of peak current; Base wire feed: 40-70% of peak wire feed; Base time: 0.2-0.5S; Welding speed: 100-250mm / min; Welding voltage: 8-15V S7), matching filler and cover: downward welding is used, with a wire extension of 8-14mm and a single-layer welding thickness of 2-3mm. The cover uses two-pass welding, and the welding parameters are as follows: 0°-20°: Wire feed speed: 280-330 IPM; Welding speed: 350-480 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3-7 mm; Dwell time: 0.05-0.15 s; Voltage: 19-26 V 20°-120°: Wire feed speed: 290-350 IPM; Welding speed: 380-520 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3-7 mm; Dwell time: 0.05-0.15 s; Voltage: 19-26 V 120°-140°: Wire feed speed: 270-320 IPM; Welding speed: 330-440 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3.2-7.2 mm; Dwell time: 0.1-0.2 s; Voltage: 18.5-25 V 140°-160°: Wire feed speed: 240-290 IPM; Welding speed: 290-380 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3.4-7.4 mm; Dwell time: 0.15-0.25 s; Voltage: 18-24 V 160°-180°: Wire feed speed: 200-250 IPM; Welding speed: 250-330 mm / min; Oscillating speed: 1-2 m / min; Oscillating amplitude: 3.6-7.6 mm; Dwell time: 0.25-0.4 s; Voltage: 18-23 V S8) Information collection and storage: Record the data of the device operation and store it in the device's memory or upload it to the server for subsequent analysis; The high- and low-frequency dual-pulse power supply uses a fully automatic tungsten inert gas welding power supply with high- and low-frequency cyclic output function. The control system can make the power supply work at one working point for a certain period of time, then switch to another working point, work for a certain period of time, and then return to the previous working point, switching cyclically. The switching frequency is 0.2-10Hz. One working point is responsible for melting the blunt edge, and the other working point is used to cool the molten pool while maintaining the arc. At both working points, the welding current is superimposed with high-frequency pulses. The pulse frequency is set to 500-15000Hz, and the base current of the high-frequency pulse is 50-150% of the given current.

2. The method for high-speed automatic argon arc welding root welding of long-distance pipelines according to claim 1, characterized in that: The root weld thickness is 3-3.5mm.

3. The method for high-speed automatic argon arc welding root welding of long-distance pipelines according to claim 1, characterized in that: The welding wire used is 1.0 mm diameter argon arc welding wire, and the tungsten electrode is 3.2 mm or 4.0 mm diameter.

4. The method for high-speed automatic argon arc welding root welding of long-distance pipelines according to claim 1, characterized in that: Use 1.2mm solid welding wire for filling and covering, with a welding current of 150-280A.

5. The method for high-speed automatic argon arc welding root welding of long-distance pipelines according to claim 1, characterized in that: After welding is completed, inspections are carried out, including RT testing, AUT testing, and mechanical property testing.

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