Arc welding repair method for aero-engine oil-gas pipe damage

Abstract

This invention relates to an arc welding repair method for damaged oil and gas pipeline components in aero-engines, comprising: S1, 3D modeling of the pipeline component; S2, removal of the damaged joint segment; S3, preparation of a replacement joint segment; S4, tack welding assembly; and S5, arc welding of the pipeline component. This invention uses 3D optical scanning measurement to establish a 3D model of the undamaged pipeline component, obtaining the external dimensions and vectors of the missing joint segment, and fabricating a replacement joint segment. A six-axis robotic arm is used to correct misalignment at the interface, axial deviation, and angular deviation during the tack welding assembly process, ensuring that the completed tack welded pipeline component is consistent with the original 3D model. Finally, arc welding is used to repair the damaged pipeline component. This method solves the problem of poor consistency in external dimensions and spatial vectors between the repaired and original pipeline components, ensuring that the repaired pipeline component can be installed on the engine.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, and specifically relates to an arc welding repair method for damaged oil and gas pipe components of aero-engines. Background Technology

[0002] Aero-engine piping is primarily used for transporting media such as hydraulic oil, fuel, lubricating oil, and air, and is a crucial component ensuring reliable engine operation. Due to the high levels of vibration during aero-engine operation, piping is exposed to intense mechanical vibration and noise, causing damage such as abrasions and dents on the contact surfaces of the piping and its fasteners due to vibration wear and collisions. Replacing the damaged parts with arc welding to restore the original dimensions of the piping can reduce the number of spare parts needed for the engine, shorten maintenance cycles, and lower the total lifespan cost of the engine.

[0003] Due to the compact engine structure and limited space for pipe installation, all engine pipes employ a curved design and are manufactured using thin-walled metal tubing with a small outer diameter. When replacing or repairing damaged pipe sections and end fasteners, it is essential to ensure the consistency of the repaired pipe's dimensions and spatial vectors with the original pipe to guarantee its installation on the engine. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an arc welding repair method for damaged oil and gas pipe components of aero-engines. The method uses tungsten inert gas welding as the welding process, obtains a three-dimensional model of the original pipe component through a three-dimensional vision system, and obtains the external dimensions and vector of the replacement pipe section by comparing it with the three-dimensional model of the original pipe component. The welding is completed by automatic rail welding, achieving single-sided welding and double-sided forming, and ensuring that the external dimensions and vector of the repaired pipe component are consistent with those of the original pipe component.

[0005] The technical problem solved by this invention is achieved through the following technical solution:

[0006] A method for arc welding repair of damaged oil and gas pipe components in aero-engines, characterized in that the method includes the following steps:

[0007] S1. 3D modeling of pipe fittings: Use alkaline solvents to thoroughly clean the internal and external dirt of brand new or undamaged pipe fittings, and obtain the external dimensions and vectors of the pipe fittings in a free state through 3D optical scanning measurement;

[0008] S2. Remove damaged pipe fittings, joints, and pipe sections;

[0009] S3. Preparation of pipe section replacement joint;

[0010] S4. Pipe fitting tack welding assembly;

[0011] S5, pipe fitting arc welding.

[0012] Furthermore, the specific operation for removing the damaged pipe joint section in step S2 is as follows: Thoroughly clean the internal and external contaminants of the damaged pipe using an alkaline solvent; clamp one end of the damaged pipe onto the pipe clamping fixture of the constraint fixture; measure and adjust the posture of the six-axis robot using an inclinometer to make the other end of the damaged pipe horizontal; adjust the linear motion of the six-axis robot to move the other end of the damaged pipe to the zero-point positioning fixture of the constraint fixture and lock it; loosen the pipe clamping fixture, adjust the position of the six-axis robot, and clamp and lock the damaged pipe a second time; obtain the external dimensions and vector of the damaged pipe in the clamped state using three-dimensional optical scanning measurement, which coincides with the external dimensions and vector of the pipe in the free state; determine the cut at the welding position and mark it circumferentially; cut at the marked position and discard the damaged joint section; remove the repaired pipe section from the zero-point positioning fixture, use a flat-end tool to flatten the cut, and clean the burrs and debris.

[0013] Furthermore, the specific operation for preparing the replacement joint pipe section in step S3 is as follows: the repaired pipe section after the end-cutting in step S2 is installed on the zero-point positioning fixture of the constraint clamp. The external dimensions and vector of the repaired pipe section are obtained by three-dimensional optical scanning measurement. The external dimensions and vector of the repaired pipe section are compared with those of the pipe section in its free state to obtain the axial dimension of the missing joint pipe section. A replacement joint pipe section is cut at the replacement joint position using a pipe section with other damage and the same part number. The axial dimension of the cut replacement joint pipe section is more than 3mm larger than the axial dimension of the missing joint pipe section. The cut end of the cut replacement joint pipe section is finished with an end-cutting tool and the burrs and debris are cleaned. The external dimensions and vector of the replacement joint pipe section are obtained by three-dimensional optical scanning to obtain the axial dimension of the replacement joint pipe section. The axial dimension of the replacement joint pipe section is compared with that of the missing joint pipe section until the deviation is within the allowable range. The replacement joint pipe section preparation is then complete.

[0014] Furthermore, the specific operation of the pipe fitting positioning welding assembly in step S4 is as follows: the replacement joint pipe segment from step S3 is clamped on the pipe fitting clamping fixture of the constraint fixture, aligning the cuts of the repair pipe segment and the replacement joint pipe segment. The external dimensions and vectors of the assembled pipe fitting are scanned online using three-dimensional optical scanning and compared with the pipe fitting in its free state. The posture of the six-axis robot is adjusted to ensure that the misalignment at the interface, the axial deviation of the pipe fitting, and the angular deviation are within the allowable range. The six-axis robot is adjusted to make the replacement joint pipe segment linearly move away from the repair pipe segment. After cleaning the inner and outer areas near the cut, it is linearly moved back to its original position. Argon gas is connected to the pipe fitting to form a back protection for the weld. Four points are positioned and welded at equal intervals along the circumference of the weld joint to complete the pipe fitting positioning welding assembly.

[0015] Furthermore, the specific operation of the pipe fitting arc welding in step S5 is as follows: clamp the pipe fitting that has completed the tack welding assembly on the fixed fixture to ensure that the pipe section at the cut is vertical, and connect the pipe fitting to form a back protection for the weld; align the welding torch with the cut, and start the arc by blowing argon gas from the welding torch cap to displace the air in the arc-starting area, maintaining an arc-starting current of 10-38A and stable combustion for 0.5-10 seconds; move the welding torch stably along the cut at a welding current of 15-30A and an angular velocity of 150-400° / min, while simultaneously feeding the welding wire into the weld pool at a speed of 2-10mm / sec; after the welding torch rotates 360° around the cut, switch the welding current to an arc-ending current of 1-5A and stable combustion for 0.5-5 seconds, extinguish the arc after the arc-ending crater disappears, and keep the welding torch cap blowing argon gas continuously for 10-20 seconds to complete the welding.

[0016] The advantages and beneficial effects of this invention are as follows:

[0017] This invention discloses an arc welding repair method for damaged oil and gas pipeline components in aero-engines. It employs three-dimensional optical scanning measurement to establish a three-dimensional model of the undamaged component, obtaining the external dimensions and vectors of the missing joint section. A replacement joint section is then fabricated. A six-axis robotic arm is used to correct misalignment at the interface, axial deviation, and angular deviation during the tack welding assembly process, ensuring that the tack welded component maintains consistency with the original three-dimensional model. Finally, the damaged component is repaired through arc welding. This method solves the problem of poor consistency in external dimensions and spatial vectors between the repaired and original components, ensuring that the repaired component can be installed on the engine. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the constraint fixture structure used in this invention;

[0019] Figure 2 This is a schematic diagram of the constraint clamp of the present invention holding a damaged pipe fitting;

[0020] Figure 3 This is a schematic diagram of the cutting of the damaged pipe fitting according to the present invention;

[0021] Figure 4 This is a schematic diagram of the damaged pipe after being cut according to the present invention;

[0022] Figure 5 This is a schematic diagram of the dimensional test of the missing joint pipe section of the present invention;

[0023] Figure 6 This is a schematic diagram of the replacement joint pipe section of the present invention;

[0024] Figure 7 This is a schematic diagram of the tack welding assembly of the pipe fittings of the present invention;

[0025] Figure 8 This is a schematic diagram of the constraint clamp of the present invention holding the assembled pipe fitting;

[0026] Figure 9 This is a cross-sectional topographic view of the welded joint of the present invention.

[0027] Explanation of reference numerals in the attached figures

[0028] 1-Base, 2-Six-axis robot, 3-Pipe clamping fixture, 4-Zero-point positioning fixture, 5-Repair pipe section, 6-Damaged joint pipe section, 7-Missing joint pipe section, 8-Replacement joint pipe section. Detailed Implementation

[0029] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0030] An arc welding repair method for damaged oil and gas pipe components of an aero-engine, the innovation of which lies in the following steps:

[0031] S1. 3D modeling of pipe fittings: Use alkaline solvents to thoroughly clean the internal and external dirt of brand new or undamaged pipe fittings, and obtain the external dimensions and vectors of the pipe fittings in a free state through 3D optical scanning measurement;

[0032] S2. Remove damaged pipe fittings, joints, and pipe sections;

[0033] S3. Preparation of pipe section replacement joint;

[0034] S4. Pipe fitting tack welding assembly;

[0035] S5, pipe fitting arc welding.

[0036] Steps S2, S3, and S4 are performed on a constraint fixture, which consists of a base 1, a six-axis robot 2, a pipe clamping fixture 3, and a zero-point positioning fixture 4. The base is a flat plate structure and is placed horizontally. The six-axis robot 2 is located at one end of the base 1, the pipe clamping fixture 3 is located at the end of the six-axis robot 2, and the zero-point positioning fixture 4 is located at the other end of the base 1.

[0037] The specific operation for removing the damaged pipe joint segment in step S2 is as follows: Thoroughly clean the internal and external contaminants of the damaged pipe fitting using an alkaline solvent. Clamp one end of the damaged pipe fitting onto the pipe fitting clamping fixture of the constraint fixture. Measure and adjust the posture of the six-axis robot arm using an inclinometer to make the other end of the damaged pipe fitting horizontal. Adjust the linear motion of the six-axis robot arm to move the other end of the damaged pipe fitting to the zero-point positioning fixture of the constraint fixture and lock it. Release the pipe fitting clamping fixture, adjust the position of the six-axis robot arm, and clamp and lock the damaged pipe fitting again. Obtain the external dimensions and vector of the damaged pipe fitting under the clamped state using three-dimensional optical scanning measurement, which coincides with the external dimensions and vector of the pipe fitting in the free state. Determine the cut at the welding position and mark it circumferentially with A. Cut at the marked position and discard the damaged joint segment 6. Remove the repaired pipe segment 5 from the zero-point positioning fixture, use a flat-end tool to flatten the cut, and clean the machining burrs and debris.

[0038] The specific operation for preparing the replacement joint pipe section in step S3 is as follows: Install the repaired pipe section after the flat end in step S2 onto the zero-point positioning fixture of the constraint clamp. Obtain the external dimensions and vector of the repaired pipe section through three-dimensional optical scanning measurement. Compare it with the external dimensions and vector of the pipe section in its free state to obtain the axial dimension L of the missing joint pipe section 7. Use a pipe section with other damage and the same part number to cut a replacement joint pipe section 8 at the replacement joint position. The axial dimension of the cut replacement joint pipe section is more than 3mm larger than the axial dimension of the missing joint pipe section. Use a flat end mill to flatten the cut end of the cut replacement joint pipe section and clean the burrs and debris. Obtain the external dimensions and vector of the replacement joint pipe section through three-dimensional optical scanning to obtain the axial dimension L1 of the replacement joint pipe section. Compare it with the axial dimension L of the missing joint pipe section until the deviation of L1 and L is within the allowable range. The preparation of the replacement joint pipe section is then complete.

[0039] The specific operation of the pipe fitting tack welding assembly in step S4 is as follows: clamp the replacement joint pipe section from step S3 onto the pipe fitting clamping fixture of the constraint fixture, align the cut of the repair pipe section with the cut of the replacement joint pipe section, and compare the assembled pipe fitting dimensions and vectors with those of the pipe fitting in its free state using three-dimensional optical online scanning. Adjust the posture of the six-axis robot to ensure that the misalignment at the interface, the axial deviation of the pipe fitting, and the angular deviation are within the allowable range. Adjust the six-axis robot to move the replacement joint pipe section linearly away from the repair pipe section, clean the inner and outer areas near the cut, and then linearly move it back to its original position. Connect the pipe fitting to argon gas to form a back protection for the weld, and perform tack welding at four points at equal intervals along the circumference of the weld joint to complete the pipe fitting tack welding assembly.

[0040] The specific operation of arc welding of pipe fittings in step S5 is as follows: Clamp the pipe fittings that have completed the tack welding assembly on the fixed fixture, ensuring that the pipe section at the cut is vertical, and connect the pipe fittings to form a back protection for the weld; align the welding torch with the cut, and start the arc by blowing argon gas through the welding torch cap to displace the air in the arc-starting area, maintaining an arc-starting current of 10-38A and stable combustion for 0.5-10 seconds; move the welding torch steadily along the cut at a welding current of 15-30A and an angular velocity of 150-400° / min, while simultaneously feeding the welding wire into the weld pool at a speed of 2-10mm / sec; after the welding torch rotates 360° around the cut, switch the welding current to an arc-ending current of 1-5A and stable combustion for 0.5-5 seconds, extinguish the arc after the arc-ending crater disappears, and keep the welding torch cap blowing argon gas continuously for 10-20 seconds to complete the welding.

[0041] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A method of arc welding repair of a gas turbine engine oil gas tube fitting damage, characterized by: The method adopts tungsten electrode argon arc welding as a welding process, obtains a three-dimensional model of the original pipe fitting through a three-dimensional vision system, and obtains the shape size and vector of the replacement pipe segment by comparing with the three-dimensional model of the original pipe fitting, and completes welding through track automatic welding, realizes single-sided welding double-sided forming, and ensures that the shape size and vector of the repaired pipe fitting are consistent with those of the original pipe fitting; The method comprises the following steps: S1, three-dimensional modeling of the pipe fitting: the inside and outside of the brand new or undamaged pipe fitting are thoroughly cleaned with an alkaline solvent, and the shape size and vector of the pipe fitting in a free state are obtained through three-dimensional optical scanning measurement; S2, pipe fitting damage joint pipe segment removal, the specific operation is: the inside and outside of the damaged pipe fitting are thoroughly cleaned with an alkaline solvent, one end of the damaged pipe fitting is clamped on the pipe fitting clamping tool of the constraint clamp, the posture of the six-axis manipulator is measured and adjusted through the inclinometer to make the other end of the damaged pipe fitting horizontal; the linear motion of the six-axis manipulator is adjusted, and the other end of the damaged pipe fitting is moved to the zero-point positioning tool of the constraint clamp and locked; the pipe fitting clamping tool is loosened, the position of the six-axis manipulator is adjusted, the damaged pipe fitting is clamped and locked again; the shape size and vector of the damaged pipe fitting in a clamped state are obtained through three-dimensional optical scanning measurement, and are coincident with the shape size and vector in a free state; a cut is determined at the welding position and is marked along the circumference, the cut is cut off at the marked position, and the damaged joint pipe segment is discarded; the pipe fitting repair pipe segment is taken off from the zero-point positioning tool, the cut is treated with a pipe bender, and burrs and debris are cleaned and processed; S3, preparation of the pipe fitting replacement joint pipe segment, the specific operation is: the pipe fitting repair pipe segment after the pipe bender is installed on the zero-point positioning tool of the constraint clamp, the shape size and vector of the repair pipe segment are obtained through three-dimensional optical scanning measurement, and are compared with the shape size and vector in a free state of the pipe fitting, to obtain the axial size of the missing joint pipe segment; a pipe fitting with other damages and the same part number is used to cut off the replacement joint pipe segment at the replacement joint position, and the axial size of the cut replacement joint pipe segment is greater than that of the missing joint pipe segment by more than 3 mm; the cut of the cut replacement joint pipe segment is treated with a pipe bender, and burrs and debris are cleaned and processed, the shape size and vector of the replacement joint pipe segment are obtained through three-dimensional optical scanning, and the axial size of the replacement joint pipe segment is compared with that of the missing joint pipe segment until the deviation is within the allowable range, and the preparation of the replacement joint pipe segment is completed; S4, pipe fitting positioning and welding assembly, the specific operation is: the replacement joint pipe segment of step S3 is clamped on the pipe fitting clamping tool of the constraint clamp, the cut of the repair pipe segment and the replacement joint pipe segment is aligned, the shape size and vector of the assembled pipe fitting are obtained through three-dimensional optical online scanning, and are compared with those in a free state of the pipe fitting, the posture of the six-axis manipulator is adjusted, the misalignment of the interface, the axial deviation of the pipe fitting, and the angle deviation are within the allowable range; the replacement joint pipe segment is linearly moved away from the repair pipe segment by adjusting the six-axis manipulator, the inside and outside areas near the cut are cleaned and then linearly moved back to the original position; the pipe fitting is connected with argon to form a weld back protection, four points are positioned and welded at equal distances along the weld circumference, and the pipe fitting positioning and welding assembly is completed. S5, pipe arc welding, the specific operation is: the completion of the positioning welding assembly pipe clamped in the fixed tooling, ensure that the cut site pipe segment vertical, pipe joint through the argon weld back protection; welding gun aligns the cut, through the welding gun gas cap blows out the argon gas to clear the air after the arc area, keep the arc current 10-38A, stable combustion 0.5-10 seconds; welding gun stable with welding current 15-30A, 150-400 ° / min angular velocity along the cut movement, while the welding wire 2-10 mm / sec speed to the welding pool filling welding wire; welding gun rotates around the cut 360 ° after welding current switch to the arc current 1-5A, stable combustion 0.5-5 seconds, wait for the arc pit disappears after extinguishing the arc, keep the welding gun gas cap continues to blow out argon 10-20 seconds, welding is completed.

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