Ultra-long conveying pipeline welding process
By adopting specific welding construction methods in API_5L_X65M_HFW pipeline construction, including material selection, pipeline bevel processing and welding parameter optimization, the problems of poor weldability and low welding quality are solved, and the welding quality and safety are significantly improved.
Patent Information
- Application Number
- CN202510062616.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-15
- Publication Date
- 2025-03-18
AI Technical Summary
During the traditional construction process, the API_5L_X65M_HFW pipeline has poor weldability, low welding quality, poor mechanical properties and corrosion resistance of welding joints, resulting in frequent bursts and leakage accidents.
An ultra-long conveying pipeline welding construction method is adopted, including material selection, pipeline bevel processing, welding surface cleaning, welding process and specific steps of welding parameters. Specific steps include root welding, fill welding and cover welding, using specific welding rods and wires, for pipe opening preheating and ultrasonic detection.
The quality of pipeline steel welding construction has been significantly improved, the difficulty of welding construction has been reduced, the performance of welding joints has been ensured, the safety of pipelines has been improved, and the research direction of API_5L_X65M_HFW pipeline welding construction technology has been broadened.
Smart Images
Figure CN119634886A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of large-scale pipeline welding, and in particular relates to a welding process for an ultra-long conveying pipeline. Background Art
[0002] Compared with ordinary pipes, HFW pipes have many advantages such as strong corrosion resistance, smooth surface, high dimensional accuracy, and easy anti-corrosion coating to improve corrosion resistance. The Guangxi Guangtou Beihai Green Ecological Aluminum Project undertaken by our company uses API_5L_X65M_HFW pipes for laying red mud pipelines. This type of pipeline has poor weldability and is prone to defects such as cracks, pores, slag inclusions, incomplete penetration, and unfused sides in the weld due to improper welding process. There have been many HFW pipeline burst and leakage accidents, most of which were caused by failure of welding joints, which caused great economic losses and buried great hidden dangers for safety. Therefore, the API_5L_X65M_HFW pipe welding process has become a key technology to ensure construction quality during pipeline construction. Summary of the invention
[0003] The technical problem to be solved by the present invention is that the HFW pipeline has poor weldability, low welding quality, and poor mechanical properties and corrosion resistance of the welded joint during the traditional construction process.
[0004] The present invention solves the above-mentioned problem by adopting the following technical solution: A welding construction method for an ultra-long transmission pipeline: the first step is material selection, the main welding material is API_5L_X65M_HFW steel pipe; the second step is pipeline groove processing; the third step is welding surface cleaning, measuring the size of each groove, and cleaning the rust, oil stains and burrs within 25mm on both sides of the groove until the metallic luster is exposed; the fourth step is welding the pipeline; the fifth step is post-weld treatment, after the welding is completed, air cooling to room temperature and then ultrasonic testing or non-destructive testing; wherein, The welding method and welding materials are as follows: the root welding adopts arc welding, and the welding rod is Φ3.2mm BOEHLER FOXCELE6010; the filling and capping welding adopts self-shielded flux-cored wire semi-automatic welding, and the flux-cored wire is Φ2.0 HOBARTFABSHIELD 81N1 E71T8-NiJ H8; The groove processing is as follows: the size of the pipe mouth is measured and adjusted, and the pipe mouth is polished with a groove opening tool at the construction site to produce a groove. The groove is a V-shaped groove with a blunt edge of 1.2mm to 2.0mm, an angle of 60°±5°, and a gap of 1.6mm to 2.0mm between pipe assemblies; The welding process and welding parameters are: 401) Preheat the pipe nozzle within 50mm; 402) When welding the root, use welding voltage: 26-30V, welding current: 70-90A, welding speed: 11-13cm / min for one upward welding, and the internal welding height of the pipe is less than 0.5mm; 403) When filling welding, use welding voltage: 20-24V, welding current: 100-110A, welding speed: 13-15cm / min to perform 2-8 downward welding to fill the inside of the groove; 404) Cover welding: Select welding voltage: 20-24V, welding current: 100-110A, welding speed: 13-15cm / min, swing distance 5mm on each side, swing frequency 1Hz / s, no dwell time, and weld downward in one pass to fill the inside of the groove.
[0005] Compared with the prior art, the present invention using the above method has the following beneficial effects: 1) The patent of this invention solves the problem of difficult welding and poor welding quality of API_5L_X65M_HFW pipelines. The welding process provided by this solution greatly improves the quality of pipeline steel welding construction, reduces the difficulty of welding construction, ensures the performance of welding joints, and improves the safety of pipelines. 2) The present invention broadens the research direction of API_5L_X65M_HFW pipeline welding construction technology, changes the inherent perception that pipelines used in the construction process of traditional transportation pipelines are prone to bursting and leakage accidents, and provides new material options for long-distance transportation pipelines. 3) The welding materials such as welding wires and electrodes used in the present invention are universal and easy to obtain, which improves the economy of this method.
[0006] As a preferred embodiment, a further technical solution of the above structure is: The swing parameters are fine-tuned with the welding position. If it is at the upper part of the pipeline, the swing frequency is reduced accordingly; if overhead welding is performed at the lower part of the pipeline, the swing frequency is increased accordingly.
[0007] The pipe mouth is preheated by induction heating or electric heating equipment. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 It is a schematic diagram of the pipeline groove of the present invention; Figure 2 It is a structural diagram of the welding layer of the present invention; DETAILED DESCRIPTION
[0009] The present invention will be further described below in conjunction with embodiments, the purpose of which is only to provide a better understanding of the content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.
[0010] Focusing on the welding process of ultra-long transmission pipelines, this paper describes an ultra-long transmission pipeline welding process, which realizes the welding of API_5L_X65M ultra-long distance transmission pipeline steel, and the mechanical properties of the welded joint are excellent. This scheme takes D325*9.5mmAPI_5L_X65M_HFW as the basis for welding process research. Figure 1 to Figure 2 , The present invention provides a super-long conveying pipeline welding construction method, which comprises the following steps: The first step is material selection: the main welding material is API_5L_X65M_HFW steel pipe; the root welding adopts arc welding, and the welding rod is Φ3.2mm BOEHLER FOX CELE6010; the filling and capping welding adopts self-shielded flux-cored wire semi-automatic welding, and the flux-cored wire is Φ2.0 HOBART FABSHIELD 81N1 E71T8-NiJ H8.
[0011] The second step is pipe groove processing: Since it is difficult to select and match the pipe ends with grooves, the pipe mouth size is measured and adjusted before welding. The pipe mouth is polished with a groove opening tool at the construction site to produce a groove. The groove is a V-shaped groove with a blunt edge of 1.2mm~2.0mm, an angle of 60°±5°, and a gap of 1.6mm~2.0mm between pipe assemblies.
[0012] The third step is to clean the weld surface: measure the size of each groove and clean up rust, oil stains, burrs and other debris within 25mm on both sides of the groove until the metallic luster is exposed.
[0013] The fourth step is to weld the pipeline. The welding process and welding parameters are as follows: 401) Preheating: Preheat the pipe mouth by induction heating or electric heating within 50mm of the pipe mouth; 402) Root welding: Use welding voltage: 26-30V, welding current: 70-90A, welding speed: 11-13cm / min for one upward welding, and the internal welding height of the pipe is less than 0.5mm; 403) Filling welding: Use welding voltage: 20-24V, welding current: 100-110A, welding speed: 13-15cm / min to perform 2-8 downward welding to fill the inside of the groove; 404) Cover welding: Select welding voltage: 20-24V, welding current: 100-110A, welding speed: 13-15cm / min, swing distance 5mm on each side, swing frequency 1Hz / s, no dwell time, and weld downwards to fill the groove. Swing parameters should be fine-tuned with welding position. For example, it is easy to form a depression at the top of the pipe (at 12 o'clock). The swing frequency should be reduced accordingly; when welding overhead at the bottom of the pipe (at 5-6, 6-7 o'clock), it is easy to fall and bite, and the swing frequency should be increased accordingly.
[0014] Step 5, post-weld treatment: After welding is completed, air cool to room temperature and then conduct ultrasonic testing or non-destructive testing. Observe the weld morphology, which should not be larger than 2.0mm, and should not have defects such as cracks, lack of fusion, pores, slag inclusions, arcing marks, harmful weld bumps, pits, and fixture welding points. After the inspection is correct, proceed with subsequent anti-corrosion construction.
[0015] The present invention is a new type of welding process with strong weldability, good welding forming quality, excellent mechanical properties of welded joints, and excellent corrosion resistance. It avoids quality problems such as undercut, pores, weld nodules, and weld slag in welded joints, ensures that welded joints will not become weak points in the mechanical properties of the overall structure, and provides a good welding process for the actual engineering application of API_5L_X65M_HFW pipelines.
[0016] After many times of non-destructive testing and welding process assessment, no welding defects were detected in the non-destructive testing. Bending test and tensile test were carried out in the welding process assessment. The assessment requirements were passed in the bending test, and the fracture positions in the tensile test were all on the parent material, and the tensile strength was greater than or equal to 95% of the SMTS of the pipe, meeting the assessment requirements.
[0017] The beneficial effects of the present invention are: 1) The patent of this invention solves the problem of difficult welding and poor welding quality of API_5L_X65M_HFW pipeline. The welding process provided by this solution greatly improves the quality of pipeline steel welding construction, reduces the difficulty of welding construction, ensures the performance of welding joints, and improves the safety of pipelines.
[0018] 2) The present invention broadens the research direction of API_5L_X65M_HFW pipeline welding construction technology, changes the inherent perception that pipelines used in traditional pipeline construction processes are prone to bursting and leakage accidents, and provides new material options for long-distance pipelines.
[0019] 3) The welding materials such as welding wire and welding rod used in the present invention are universal and easy to obtain, which improves the economic efficiency of the method.
[0020] The above description is only a preferred feasible embodiment of the present invention, and does not limit the scope of rights of the present invention. All equivalent changes made using the contents of the present specification and its drawings are included in the scope of rights of the present invention.
Claims
1. A welding construction method for ultra-long transmission pipelines: The first step is material selection: the main welding material is API_5L_X65M_HFW steel pipe; The second step is pipe groove processing; The third step is to clean the weld surface: measure the size of each groove and clean the rust, oil and burrs within 25mm on both sides of the groove until the metallic luster is exposed; The fourth step is to weld the pipeline; Step 5, post-weld treatment: After welding is completed, air cool to room temperature and then conduct ultrasonic testing or non-destructive testing; It is characterized in that The welding method and welding materials are as follows: the root welding adopts arc welding, and the welding rod is Φ3.2mm BOEHLER FOXCELE6010; the filling and capping welding adopts self-shielded flux-cored wire semi-automatic welding, and the flux-cored wire is Φ2.0 HOBARTFABSHIELD 81N1 E71T8-NiJ H8; The groove processing is as follows: the size of the pipe mouth is measured and adjusted, and the pipe mouth is polished with a groove opening tool at the construction site to produce a groove. The groove is a V-shaped groove with a blunt edge of 1.2mm to 2.0mm, an angle of 60°±5°, and a gap of 1.6mm to 2.0mm between pipe assemblies; The welding process and welding parameters are: 401) Preheat the pipe nozzle within 50mm; 402) When welding the root, use welding voltage: 26-30V, welding current: 70-90A, welding speed: 11-13cm / min for one upward welding, and the internal welding height of the pipe is less than 0.5mm; 403) When filling welding, use welding voltage: 20-24V, welding current: 100-110A, welding speed: 13-15cm / min to perform 2-8 downward welding to fill the inside of the groove; 404) Cover welding: Select welding voltage: 20-24V, welding current: 100-110A, welding speed: 13-15cm / min, swing distance 5mm on each side, swing frequency 1Hz / s, no dwell time, and weld downward in one pass to fill the inside of the groove.
2. The ultra-long conveying pipeline welding construction method according to claim 1 is characterized in that: The swing parameters are fine-tuned with the welding position. If it is at the upper part of the pipeline, the swing frequency is reduced accordingly; if overhead welding is performed at the lower part of the pipeline, the swing frequency is increased accordingly.
3. The ultra-long conveying pipeline welding construction method according to claim 1 is characterized in that: The pipe mouth is preheated by induction heating or electric heating equipment.