One-side welding and double-side forming method for carbon dioxide welding of pipeline

Abstract

The invention provides a one-side welding and double-side forming method for carbon dioxide welding of a pipeline, which comprises the following steps: a preparation step before welding: carrying out groove processing and cleaning on the pipeline, and carrying out assembly and pipeline positioning welding on pipe orifices; welding, wherein backing welding is conducted on the pipeline; and a welding acceptance inspection step: carrying out surface cleaning and weld bead appearance quality inspection on the welded pipeline, and if the welded pipeline is not qualified, carrying out repair and repair until the welded pipeline is qualified so as to complete the welding of the pipeline. The method is wide in application range and can be widely applied to backing weld bead welding of an automatic pipeline carbon dioxide welding machine; compared with common manual argon arc welding bottoming, the welding efficiency is greatly improved, the welding quality is high, the UT one-time detection percent of pass of a welding seam reaches 99% or above, the automatic pipeline welding labor intensity is good, the requirement for the skill level of a welder is low, and the formed welding seam is attractive.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline welding, and in particular to a single-sided welding and double-sided forming method for pipeline carbon dioxide welding. Background Art

[0002] At present, the main methods on the market for achieving single-sided welding and double-sided forming of pipeline base welds without lining are manual argon arc welding, automatic argon arc welding and internal welding machines widely used in long oil pipelines. However, it is difficult to weld the base welds using pipeline carbon dioxide automatic welding machines, and there is a lack of effective single-sided welding and double-sided forming processes. Summary of the invention

[0003] In view of this, the present invention proposes a single-sided welding and double-sided forming method for pipeline carbon dioxide welding, aiming to solve the problem that existing carbon dioxide pipeline automatic welding machines are difficult to weld the base weld and lack effective single-sided welding and double-sided forming processes.

[0004] The present invention proposes a single-sided and double-sided forming method for carbon dioxide welding of pipelines, which comprises the following steps: a pre-welding preparation step, in which groove processing and cleaning of pipelines are performed, and pipe openings are assembled and pipeline positioning welding is performed; a welding step, in which base welding is performed on the pipeline; a welding acceptance step, in which the surface of the pipeline after welding is cleaned and the appearance quality of the weld is inspected. If the pipeline is unqualified, repair and rework are performed until the pipeline is qualified after inspection, thereby completing the welding of the pipeline.

[0005] Furthermore, in the above-mentioned pipeline carbon dioxide welding single-sided welding and double-sided forming method, the pre-welding preparation step includes the following sub-steps: a pipe groove processing sub-step, preparing and processing the pipeline groove; a groove cleaning sub-step, cleaning the groove and both sides inside and outside the groove; a pipe mouth pairing sub-step, pairing the pipe mouths; a matching inspection sub-step, measuring the weld groove angle, width, blunt edge, misalignment, end face flatness, and gap; a positioning welding sub-step, using a three-point positioning method to perform pipeline positioning welding.

[0006] Furthermore, in the above-mentioned single-sided welding and double-sided forming method of pipeline carbon dioxide welding, in the pipe mouth assembly sub-step, the welding groove assembly gap is 2-4mm, the blunt edge is 0.5-1m, and the misalignment is less than or equal to 10% of the pipe wall thickness and less than or equal to 2mm.

[0007] Furthermore, in the above-mentioned pipeline carbon dioxide welding single-sided welding and double-sided forming method, in the positioning welding sub-step, the positioning weld has a length of 30 to 50 mm and a height of 2 to 4 mm. Both ends of the positioning weld are ground into a gentle slope, and the thickness of the joint with the formal weld is less than 0.2 mm.

[0008] Furthermore, in the above-mentioned pipeline carbon dioxide welding single-sided welding double-sided forming method, the welding step includes the following sub-steps: an equipment debugging sub-step, debugging the welding equipment and inputting welding process parameters; wherein the welding process parameters include equipment voltage, equipment current, swing width, swing speed, left and right stop parameters, walking speed and welding direction; a base welding sub-step, starting the arc in the middle of the positioning welding at the 12 o'clock position, welding from top to bottom to the 6 o'clock position and extinguishing the arc to complete half of the welding, and then adjusting back to the 12 o'clock position again, from then on, starting the arc in the reverse direction from top to bottom to the 6 o'clock position and extinguishing the arc to complete the other half of the welding.

[0009] Furthermore, in the above-mentioned pipeline carbon dioxide welding single-sided welding and double-sided forming method, in the base welding sub-step, the positioning welding point is located at the 12 o'clock position, the arc starting point is located at the 12 o'clock position, the moving direction is 12 o'clock→6 o'clock direction, and it moves from top to bottom in half a cycle.

[0010] Furthermore, in the above-mentioned pipeline carbon dioxide welding single-sided welding and double-sided forming method, in the base welding sub-step, a pre-walk is performed before welding to observe whether the trolley has any deviation and whether the welding gun has any swing phenomenon, so as to determine whether the welding parameters need to be changed.

[0011] Furthermore, in the above-mentioned pipeline carbon dioxide welding single-sided welding double-sided forming method, the equipment voltage is 15-17V, the equipment current is 90-130A, the swing width is 10-18mm, the swing speed is 92m / min, the left stop time and the right stop time are set to 25s, the walking speed is 28mm / min, and the protective gas is CO2.

[0012] Furthermore, in the above-mentioned pipeline carbon dioxide welding single-sided welding double-sided forming method, in the base welding sub-step, the weld back excess height is between 0 and 2 mm.

[0013] Furthermore, in the above-mentioned pipeline carbon dioxide welding single-sided welding and double-sided forming method, during the bottom weld process, the swing width is adjusted in real time, and the swing width of the flat welding position is the largest and decreases from top to bottom.

[0014] The single-sided welding and double-sided forming method for pipeline carbon dioxide welding provided by the present invention uses a pipeline carbon dioxide automatic welding machine as a carrier, performs preparation before welding, and performs welding and acceptance, thereby solving the problems that the existing carbon dioxide pipeline automatic welding machine is difficult to weld the base weld and lacks an effective single-sided welding and double-sided forming process. Compared with the relatively mature single-sided welding and double-sided forming process of internal welding machines on the market, the method is inexpensive; the method has a wide range of applications and can be widely used in the welding of the base weld of pipeline carbon dioxide automatic welding machines; the welding efficiency is compared with the commonly used manual argon arc welding base, the welding efficiency is greatly improved, the welding quality is high, the weld UT one-time inspection pass rate is more than 99%, the pipeline automatic welding has good labor intensity, low requirements on the welder's skill level, and the weld is beautifully formed. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1 A flowchart of a method for single-sided welding and double-sided forming of a pipeline carbon dioxide welding provided by an embodiment of the present invention; Figure 2 A process diagram of a single-sided and double-sided forming method for carbon dioxide welding of a pipeline provided by an embodiment of the present invention; Figure 3 A flowchart of the pre-welding preparation steps provided by an embodiment of the present invention; Figure 4 A flowchart of the welding steps provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0016] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0017] See also Figure 1 and Figure 2 , which shows a flow chart of a pipeline carbon dioxide welding single-sided welding double-sided forming method provided by an embodiment of the present invention. As shown in the figure, the pipeline carbon dioxide welding single-sided welding double-sided forming method includes the following steps: The pre-welding preparation step S1 is to process and clean the pipe groove, assemble the pipe mouth and perform pipe positioning welding.

[0018] Welding step S2, performing base welding on the pipeline.

[0019] Welding acceptance step S3, cleaning the surface of the pipeline after welding and inspecting the appearance quality of the weld. If it is unqualified, repair and rework are performed until it passes the inspection, and the welding of the pipeline is completed.

[0020] Specifically, the surface of the pipeline after welding can be cleaned first, and then the weld appearance quality inspection of the pipeline is carried out. If the weld appearance quality inspection fails, the weld is repaired until the weld appearance quality inspection passes; if the weld appearance quality inspection passes, the pipeline is subjected to non-destructive testing; when the pipeline non-destructive testing passes, the welding is completed, that is, the welding of the pipeline is completed; otherwise, that is, the pipeline non-destructive testing fails, it is repaired, and after the repair, the process jumps to the weld appearance quality inspection and non-destructive testing again until the welding is completed.

[0021] Continue to see Figure 2 and Figure 3 , the pre-welding preparation step S1 includes the following sub-steps: The pipe groove processing sub-step S11 is to prepare and process the pipe groove.

[0022] Specifically, the automatic processing method is used for the preparation of pipeline grooves, and the grinding method is used for on-site assembly and finishing, elimination of groove defects after processing, and processing of small-diameter pipes. If hot processing methods (such as flame cutting and plasma cutting) are used for cutting, the cut part should have an automatic processing allowance to facilitate the removal of the hardened layer and overheated metal.

[0023] The groove cleaning sub-step S12 is to clean the groove and both sides of the groove.

[0024] Specifically, the groove and both sides of the groove must be cleaned before welding to ensure that there is no dirt within 20 mm on both sides of the groove.

[0025] The pipe orifice pairing sub-step S13 is to pair the pipe orifices.

[0026] Specifically, the gap between the welds should be controlled as required, the blunt edge should be 0.5-1mm, the misalignment should keep the inner wall flush, the inner wall misalignment should not exceed 10% of the pipe wall thickness, and should not be greater than 2mm. If the part exceeds the standard, it should be corrected to the specified size, and forced assembly is strictly prohibited during the assembly process. In other words, the gap between the weld grooves should be 2-4mm, the blunt edge should be 0.5-1m, and the misalignment should be less than or equal to 10% of the pipe wall thickness and less than or equal to 2mm.

[0027] In the joint inspection sub-step S14, the weld groove angle, width, blunt edge, misalignment, end surface flatness and gap are measured.

[0028] Specifically, use a special weld inspection ruler or other measuring tools to measure the weld groove angle, width, blunt edge, misalignment, end surface flatness, gap, etc. and meet the requirements. There are no cracks, heavy skin, groove damage, burrs and other defects in the parent material within the groove and within 20mm of the edge. For steel with a greater tendency to harden, the surface is cut or grooved by hot processing, and non-destructive testing or hardness testing is carried out. The inspection of the deflection between the end face of the pipe and the center line of the pipe should meet the requirements of the specification.

[0029] The positioning welding sub-step S15 uses a three-point positioning method to perform pipeline positioning welding.

[0030] Specifically, the pipeline tack welding should be symmetrically and evenly distributed, and the number of tack welding points should be set according to the pipe diameter. For pipes ≤300mm, the three-point tack method is recommended. The welding materials, welding process and preheating temperature during tack welding should be the same as those for formal welding. Tack welding should ensure that the weld will not crack during the formal welding process. Its length should be 30-50mm, and its height should be 2-4mm. Both ends of the tack weld should be easy to connect the arc (grinded into a gentle slope, and the thickness at the junction with the formal weld is less than 0.2mm), otherwise it should be trimmed. Therefore, the length of the tack weld is 30-50mm, the height is 2-4mm, and the two ends of the tack weld are ground into a gentle slope, and the thickness at the junction with the formal weld is less than 0.2mm. After the tack welding is completed, the welding equipment is installed to weld the pipeline.

[0031] Continue to see Figure 2 and Figure 3 , the welding step S2 includes the following sub-steps: The equipment debugging sub-step S21 debugs the welding equipment and inputs welding process parameters; wherein the welding process parameters include equipment voltage, equipment current, swing width, swing speed, left and right stop parameters, travel speed and welding direction.

[0032] Specifically, the debugging of welding equipment and the setting of various process parameters: Before welding, the welding equipment should be debugged to ensure that all parts of the equipment are operating normally, and various welding process parameters should be input according to the following table. That is, the equipment voltage is 15-17V, the equipment current is 90-130A, the swing width is 10-18mm, the swing speed is 92m / min, the left stop time and the right stop time are set to 25s, the travel speed is 28mm / min, and the shielding gas is CO2.

[0033] Welding process parameter table In the base welding sub-step S22, the arc is started in the middle of the positioning welding at the 12 o'clock position, and the arc is extinguished from top to bottom at the 6 o'clock position to complete the welding of half side, and then the position is adjusted back to the 12 o'clock position. From then on, the arc is started in the reverse direction from top to bottom to the 6 o'clock position to extinguish the arc to complete the welding of the other half side.

[0034] Specifically, fix the welding gun vertically above the 12-point positioning welding, adjust the welding mode to mode 2, set the swing width according to the groove gap and groove angle, and set the left and right stop times to 25. Set the current, voltage, swing width, swing speed, and travel speed, adjust the mode to non-welding mode, determine the travel direction, and click the start button, that is, the arc is started in the middle of the 12-point positioning welding, and the arc is extinguished from top to bottom at the 6 o'clock position, and then the newly completed weld joint is polished to a long slope, and the trolley is adjusted back to the 12 o'clock position to start the arc, and the remaining half of the welding is completed; that is, the positioning welding point is at the 12 o'clock position, the arc starting point is at the 12 o'clock position, and the travel direction is 12 o'clock → 6 o'clock direction, and it travels from top to bottom in half a cycle. When welding, the back should be well formed, the weld back excess height is between 0~2mm, and the weld and the groove are well integrated. When welding the base weld, the swing width (swing amplitude) should be adjusted. Usually, the swing width of the flat welding position is the largest, and it decreases from top to bottom. The travel speed is used as an auxiliary adjustment for the base weld, and other parameters should remain unchanged as much as possible. The trolley moves along the predetermined welding track to observe whether the trolley deviates and the welding gun deviates. If so, adjustments should be made in time. In other words, before welding, a preliminary walk should be conducted to observe whether the trolley deviates and the welding gun deviates, so as to determine whether the welding parameters need to be changed.

[0035] In summary, the single-sided welding and double-sided forming method for pipeline carbon dioxide welding provided in this embodiment uses the pipeline carbon dioxide automatic welding machine as a carrier to prepare before welding, and performs welding and acceptance, thereby solving the problem that the existing carbon dioxide pipeline automatic welding machine is difficult to weld the base weld and lacks an effective single-sided welding and double-sided forming process. Compared with the relatively mature single-sided welding and double-sided forming process of the internal welding machine on the market, this method is inexpensive; the method has a wide range of applications and can be widely used in the base weld welding of pipeline carbon dioxide automatic welding machines; the welding efficiency is greater than the commonly used manual argon arc welding base, the welding efficiency is greatly improved, the welding quality is high, the weld UT one-time inspection pass rate is more than 99%, the pipeline automatic welding has good labor intensity, low requirements on the welder's skill level, and the weld is beautiful.

[0036] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0037] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A pipeline carbon dioxide welding single-sided welding double-sided forming method, characterized in that: The steps include: Pre-welding preparation steps include beveling and cleaning the pipe, assembling the pipe ends, and performing pipe positioning welding; Welding step: base welding of the pipeline; The welding acceptance step is to clean the surface of the pipeline after welding and check the appearance quality of the weld. If it is unqualified, it will be repaired and reworked until it passes the inspection, and the welding of the pipeline is completed.

2. The pipeline carbon dioxide welding single-sided welding double-sided forming method according to claim 1 is characterized in that: The pre-welding preparation step includes the following sub-steps: The pipe groove processing sub-step is to prepare and process the pipe groove; The groove cleaning sub-step is to clean the groove and both sides of the groove; The pipe orifice pairing sub-step is to pair the pipe orifices; The sub-step of the joint inspection is to measure the weld groove angle, width, blunt edge, misalignment, end surface flatness, and gap; In the positioning welding sub-step, the three-point positioning method is used to perform pipeline positioning welding.

3. The pipeline carbon dioxide welding single-sided welding double-sided forming method according to claim 2 is characterized in that: In the pipe mouth assembly sub-step, the welding groove assembly gap is 2-4mm, the blunt edge is 0.5-1m, and the misalignment is less than or equal to 10% of the pipe wall thickness and less than or equal to 2mm.

4. The pipeline carbon dioxide welding single-sided welding double-sided forming method according to claim 2 is characterized in that: In the positioning welding sub-step, the length of the positioning weld is 30-50 mm, the height is 2-4 mm, the two ends of the positioning weld are ground into a gentle slope, and the thickness at the junction with the formal weld is less than 0.2 mm.

5. The pipeline carbon dioxide welding single-sided welding double-sided forming method according to any one of claims 1 to 4, characterized in that: The welding step includes the following sub-steps: The equipment debugging sub-step is to debug the welding equipment and input welding process parameters; wherein the welding process parameters include equipment voltage, equipment current, swing width, swing speed, left and right stop parameters, travel speed and welding direction; The base welding sub-step is to start the arc in the middle of the positioning welding at the 12 o'clock position, weld from top to bottom to the 6 o'clock position and extinguish the arc to complete the welding of half side, and then adjust back to the 12 o'clock position, and then start the arc in the reverse direction from top to bottom to the 6 o'clock position and extinguish the arc to complete the welding of the other half side.

6. The pipeline carbon dioxide welding single-sided welding double-sided forming method according to claim 5 is characterized in that: In the base welding sub-step, the positioning welding point is located at the 12 o'clock position, the arc starting point is located at the 12 o'clock position, the moving direction is 12 o'clock→6 o'clock, and the moving is from top to bottom in half a cycle.

7. The pipeline carbon dioxide welding single-sided welding double-sided forming method according to claim 5 is characterized in that: In the base welding sub-step, before welding, a preliminary walk is performed to observe whether the carriage is deviated and whether the welding gun is swung, so as to determine whether the welding parameters need to be changed.

8. The pipeline carbon dioxide welding single-sided welding double-sided forming method according to claim 5 is characterized in that: The device voltage is 15-17V, the device current is 90-130A, the swing width is 10-18mm, the swing speed is 92m / min, the left stop time and the right stop time are set to 25s, the walking speed is 28mm / min, and the protective gas is CO2.

9. The pipeline carbon dioxide welding single-sided welding double-sided forming method according to any one of claims 1 to 4, characterized in that: In the base welding sub-step, the weld back height is between 0 and 2 mm.

10. The pipeline carbon dioxide welding single-sided welding double-sided forming method according to claim 9, characterized in that: During the base weld process, the swing width is adjusted in real time. The swing width in the flat welding position is the largest and decreases from top to bottom.

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