Welding method of fuel supply pipeline

Abstract

The invention belongs to the technical field of fuel transportation, and discloses a welding method of a fuel supply pipeline, which comprises the following steps: welding and connecting the end parts of a plurality of first pipe joints to form an inner pipe, fixing cushion blocks outside the inner pipe, arranging a plurality of cushion blocks at intervals along the length direction of the inner pipe, and welding the inner pipe after a welding seam is qualified through nondestructive inspection. A plurality of second pipe joints are arranged outside the inner pipe, the cushion blocks are supported on the inner walls of the second pipe joints, the ends of the second pipe joints are welded and connected to form an outer pipe, and the welding positions of the two first pipe joints of the inner pipe and the welding positions of the two second pipe joints of the outer pipe are arranged in a staggered mode in the axial direction of the fuel supply pipeline; the welding steps of welding every two first pipe joints and welding every two second pipe joints comprise preparation before welding, groove machining, pipe butt joint positioning, protective gas filling, positioning point fixed welding and welding. According to the welding method of the fuel supply pipeline, welding is carried out strictly according to appropriate current and temperature control values, surface forming of a weld joint is improved, and welding quality is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of fuel transportation, and in particular to a welding method for a fuel supply pipeline. Background Art

[0002] Bulk carrier is the abbreviation of bulk cargo ship, which is specially used to transport unpackaged goods such as coal, ore, timber, livestock, grain, etc.

[0003] At present, the gas fuel supply pipe system of the dual-fuel diesel engine of bulk carriers usually adopts the form of double-wall pipes, the inner pipe is used for gas transmission, and the cavity between the inner pipe and the outer pipe is continuously exhausted by the fan. Such a setting can avoid the danger caused by pipeline welding defects as much as possible. Even if the inner pipe leaks, the outer sleeve can be isolated and protected, and the leaked gas will be immediately discharged to the open-air safe area by the exhaust fan, reducing the risk of fire and explosion.

[0004] Usually, leakage of the inner tube is mostly caused by welding defects such as pores and weld oxidation generated during the welding process of each section of the inner tube. Therefore, it is urgent to design a new welding method for the fuel supply pipeline to improve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a welding method for a fuel supply pipeline to solve welding defects such as pores and weld oxidation generated during the welding process.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A welding method for a fuel supply pipeline, comprising: welding the ends of a plurality of first pipe segments to form an inner pipe, fixing a cushion block on the outside of the inner pipe and arranging a plurality of the cushion blocks at intervals along the length direction of the inner pipe, arranging a plurality of second pipe segments on the outside of the inner pipe and supporting the cushion blocks on the inner walls of the second pipe segments after the welds are qualified through non-destructive testing, welding the ends of a plurality of the second pipe segments to form an outer pipe, and staggering the welding points of the two first pipe segments of the inner pipe and the welding points of the two second pipe segments of the outer pipe along the axial direction of the fuel supply pipeline;

[0008] The welding steps for welding every two of the first pipe sections and welding every two of the second pipe sections are the same and are as follows:

[0009] S1. Preparation before welding: check the specifications and quality of the first pipe section and the second pipe section to be welded, and select appropriate welding wire;

[0010] S2, groove processing, according to the preset groove size, using a pipe groove machine to perform groove processing on the first pipe section and the second pipe section, and cleaning the welding wire and the formed groove and the processing residues within a certain range around it;

[0011] S3, butting and positioning the pipes, butting the welding surfaces of the two first pipe sections or butting the welding surfaces of the two second pipe sections, and reserving an assembly gap between the two, and placing the welding wire in the assembly gap;

[0012] S4, filling with protective gas, using manual tungsten inert gas welding single-sided welding and double-sided forming welding to seal the two ends of the two first pipe sections that are far away from each other or to seal the gap between the two first pipe sections and the two second pipe sections, and filling the sealed space with argon gas;

[0013] S5. Position the spot welding, use the DC positive connection method to spot weld the weld, and check to confirm that the weld has no cracks or other defects;

[0014] S6. Welding: adjust the tungsten electrode extension length according to the weld layer, select the welding current according to the wire diameter and pipe wall thickness, and maintain the temperature range within the appropriate range for welding.

[0015] As a preferred solution of the welding method of the fuel supply pipeline, in the step S1, the first pipe section and the second pipe section are both made of stainless steel, and the wall thickness of the first pipe section and the second pipe section is 3 mm to 6 mm;

[0016] The material of the welding wire is the same as or compatible with the material of the first pipe section and the second pipe section, and the diameter of the welding wire is 2 mm or 2.4 mm.

[0017] As a preferred solution of the welding method of the fuel supply pipeline, in the step S2, the preset groove size includes:

[0018] The shape of the preset groove is V-shaped;

[0019] The opening angle on the single-side bevel is 30°±5°;

[0020] The blunt edge thickness of the single-sided bevel is 0.8 mm to 1.2 mm;

[0021] The cleaning welding wire and the forming groove and the processing residues within a certain range around them include:

[0022] Use a stainless steel brush and / or a cloth soaked in acetone to clean the burrs, debris, oxides and oil stains remaining after processing on the forming groove and the area within 20 mm.

[0023] As a preferred solution of the welding method for the fuel supply pipeline, in the step S3, the spacing of the assembly gap is 1.5 mm to 3 mm.

[0024] As a preferred solution of the welding method of the fuel supply pipeline, in the step S4, the plugging includes plugging with a sponge or a material that does not corrode the materials of the first pipe section and the second pipe section;

[0025] The gas flow rate of the argon gas is controlled within the range of 10 to 15 L / min, and at the same time, the air in the gas delivery pipe is removed for 1 to 2 minutes.

[0026] As a preferred solution of the welding method for the fuel supply pipeline, in the step S5, the length of the spot welding seam is less than 10 mm.

[0027] As a preferred solution of the welding method for the fuel supply pipeline, in the step S6, during welding, the extension length of the tungsten electrode is adjusted to 2 mm to 5 mm, and the welding current is set to 70A to 200A.

[0028] As a preferred solution of the welding method for the fuel supply pipeline, in the step S6, when welding multiple layers, the interlayer temperature of the multiple layers is set to be less than 60°.

[0029] As a preferred solution of the welding method of the fuel supply pipeline, in the step S6, after welding, the residual height value of the front and back surfaces of the weld is h, and 0mm≤h≤2mm.

[0030] As a preferred solution of the welding method of the fuel supply pipeline, the welding step further includes:

[0031] S7. Clean up after welding, clean the weld and surrounding processing residues, and perform RT non-destructive testing.

[0032] Beneficial effects of the present invention:

[0033] By first welding a number of first pipe sections, and then fixing a pad on the outside of the formed inner tube, when the second pipe section is sleeved on the outside of the inner tube, the pad plays a supporting and positioning role for the second pipe section, ensuring that the second pipe section and the inner tube can be kept on the same axis, and then welding is performed between a number of second pipe sections, and ensuring that the welding points of the inner tube and the outer tube are staggered along the axial direction of the fuel supply pipeline, so that the radial force strength of the fuel supply pipeline is higher and the welding deformation is reduced.

[0034] In addition, the specifications and quality of the materials to be welded are checked during the pre-welding preparation, and appropriate welding wire is selected for welding to reduce the possibility of misoperation; after the groove processing is completed, the residue is carefully cleaned to avoid impurities during welding and reduce the occurrence of defects such as pores; during welding, argon gas is filled on the back to effectively isolate the air, prevent the welding materials from contacting with oxygen, prevent oxidation, ensure the quality of the welding joint, reduce the generation of smoke, and protect the welding pool from the influence of the external environment; the welding surfaces are first spot welded together through spot welding to keep them fixed, reduce the occurrence of deformation during subsequent welding, and ensure the stability of shape and size; welding is carried out strictly in accordance with appropriate current and temperature control values ​​to improve the surface forming of the weld, effectively improve the pass rate of weld surface inspection and radiographic non-destructive testing, and ensure welding quality and construction schedule. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The figure is a flow chart of a welding method for a fuel supply pipeline provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0037] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" 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 mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0039] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0040] Combination Figure 1 As shown, this embodiment provides a welding method for a fuel supply pipeline, specifically, the ends of a plurality of first pipe sections are welded together to form an inner tube, a pad is fixed on the outside of the inner tube and a plurality of pads are arranged at intervals along the length direction of the inner tube, after the weld is qualified by non-destructive testing, a plurality of second pipe sections are arranged on the outside of the inner tube and the pad is supported on the inner wall of the second pipe section, the ends of the plurality of second pipe sections are welded together to form an outer tube, and the welding points of the two first pipe sections of the inner tube and the welding points of the two second pipe sections of the outer tube are staggered along the axial direction of the fuel supply pipeline.

[0041] By first welding a number of first pipe sections, and then fixing a pad on the outside of the formed inner tube, when the second pipe section is sleeved on the outside of the inner tube, the pad plays a supporting and positioning role for the second pipe section, ensuring that the second pipe section and the inner tube can be kept on the same axis, and then welding is performed between a number of second pipe sections, and ensuring that the welding points of the inner tube and the outer tube are staggered along the axial direction of the fuel supply pipeline, so that the radial force strength of the fuel supply pipeline is higher and the welding deformation is reduced.

[0042] It should be noted that the installation and welding sequence of the double-walled pipe is that the inner pipe is completely welded, and the outer pipe is installed and welded only after the weld has passed 100% RT and other non-destructive testing, so as to reduce the difficulty of subsequent maintenance and inspection and ensure the welding quality.

[0043] Furthermore, if Figure 1 As shown, the welding steps for welding every two first pipe sections and welding every two second pipe sections are the same and are as follows:

[0044] S1. Preparation before welding: Check the specifications and quality of the first pipe section and the second pipe section to be welded, and select appropriate welding wire. In the preparation before welding, check the specifications and quality of the materials to be welded, and select appropriate welding wire accordingly to reduce the possibility of misoperation.

[0045] Specifically, the first pipe section and the second pipe section are made of stainless steel, and the wall thickness of the first pipe section and the second pipe section is 3 mm to 6 mm. The wall thickness of the pipe in this embodiment is 4 mm, and in other embodiments, it can also be 3 mm, 5 mm or 6 mm. The material of the welding wire is the same as or compatible with the material of the first pipe section and the second pipe section. The welding wire in this embodiment is also made of stainless steel. More specifically, the stainless steel welding wire is TGS-316L, and the diameter of the welding wire is 2 mm or 2.4 mm, and preferably 2 mm in this embodiment.

[0046] S2, groove processing, according to the preset groove size, use the pipe groove machine to groove the first pipe section and the second pipe section, clean the welding wire and the processing residues within a certain range of the groove and its surroundings. After the groove processing is completed, the residues are carefully cleaned to avoid impurities during welding and reduce the occurrence of defects such as pores.

[0047] Specifically, the preset groove size includes a preset groove shape of V-shape, which can also be U-shape in other embodiments. The opening angle on the single-side groove is 30°±5°, and the blunt edge thickness of the single-side groove is 0.8mm-1.2mm, and the blunt edge thickness of this embodiment is preferably 1mm.

[0048] In addition, cleaning the welding wire and the formed groove and the processing residues within a certain range around it includes using a stainless steel brush and / or a cloth strip soaked in acetone to clean the burrs, debris, oxides and oil stains remaining after processing on the formed groove and the area within 20 mm.

[0049] S3. Pipes are butt-jointed and positioned, the welding surfaces of the two first pipe sections are butt-jointed or the welding surfaces of the two second pipe sections are butt-jointed, and an assembly gap is reserved between the two, and welding wire is placed in the assembly gap.

[0050] Specifically, the spacing of the assembly gap is 1.5 mm to 3 mm. The operator wears clean gloves to perform the operation and keeps the welding wire clean during the welding process.

[0051] S4. Fill the protective gas, use manual tungsten inert gas welding single-sided welding and double-sided forming welding, seal the two ends of the two first pipe sections that are far away from each other or seal the gap between the two first pipe sections and the two second pipe sections, and fill the sealed space with argon. During welding, fill argon gas on the back to effectively isolate the air, prevent the welding material from contacting with oxygen, prevent oxidation, ensure the quality of the welded joint, reduce the generation of smoke, and protect the welding pool from the influence of the external environment.

[0052] Specifically, the plugging includes using sponge or a material that does not corrode the materials of the first pipe section and the second pipe section for plugging, and welding is performed under windproof and weatherproof conditions.

[0053] In addition, before welding, the gas flow rate of the argon gas is adjusted to be controlled within the range of 10L / min to 15L / min. At the same time, the air in the gas delivery pipe is exhausted for 1 minute to 2 minutes.

[0054] S5. Positioning spot welding, using DC positive connection method to spot weld the weld, check and confirm that the weld has no cracks or other defects before formal welding. Spot weld the welding surface together first through spot welding, keep it fixed, reduce deformation in the subsequent welding process, and ensure the stability of shape and size.

[0055] Specifically, the length of the spot welding seam is less than 10 mm.

[0056] S6. Welding: adjust the tungsten electrode extension length according to the weld layer, select the welding current according to the wire diameter and the wall thickness, and maintain the temperature range within the appropriate range for welding. Strictly follow the appropriate current and temperature control values ​​for welding to improve the weld surface shaping, effectively improve the weld surface inspection and X-ray non-destructive testing pass rate, and ensure welding quality and construction schedule.

[0057] Specifically, when welding, adjust the extension length of the tungsten electrode to 2mm~5mm, set the welding current to 70A~200A, and the arc starting and arc stopping must be carried out strictly in accordance with the joint operation specifications. When starting the arc, prevent the tungsten electrode from directly contacting the workpiece. If welding defects such as tungsten inclusions and pores occur, they can be polished out with a stainless steel grinding wheel. When welding multiple layers, set the interlayer temperature of the multiple layers to <60°. When welding joints, subtract the oxidized part of the wire end. Increase the welding speed while ensuring root and interlayer penetration. After welding, the residual height value of the front and back of the weld is h, and 0mm≤h≤2mm.

[0058] S7. Clean up after welding, clean the weld and surrounding processing residues, and perform RT non-destructive testing.

[0059] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for welding a fuel supply pipeline, characterized in that: The ends of a plurality of first pipe segments are welded together to form an inner pipe, a cushion block is fixed outside the inner pipe and a plurality of the cushion blocks are arranged at intervals along the length direction of the inner pipe, and after the weld is tested and qualified by non-destructive testing, a plurality of second pipe segments are arranged outside the inner pipe and the cushion blocks are supported on the inner wall of the second pipe segment, and the ends of a plurality of second pipe segments are welded together to form an outer pipe, and the welding points of the two first pipe segments of the inner pipe and the welding points of the two second pipe segments of the outer pipe are staggered along the axial direction of the fuel supply pipeline; The welding steps for welding every two of the first pipe sections and welding every two of the second pipe sections are the same and are as follows: S1. Preparation before welding: check the specifications and quality of the first pipe section and the second pipe section to be welded, and select appropriate welding wire; S2, groove processing, according to the preset groove size, using a pipe groove machine to perform groove processing on the first pipe section and the second pipe section, and cleaning the welding wire and the formed groove and the processing residues within a certain range around it; S3, butting and positioning the pipes, butting the welding surfaces of the two first pipe sections or butting the welding surfaces of the two second pipe sections, and reserving an assembly gap between the two, and placing the welding wire in the assembly gap; S4, filling with protective gas, using manual tungsten inert gas welding single-sided welding and double-sided forming welding to seal the two ends of the two first pipe sections that are far away from each other or to seal the gap between the two first pipe sections and the two second pipe sections, and filling the sealed space with argon gas; S5. Position the spot welding, use the DC positive connection method to spot weld the weld, and check to confirm that the weld has no cracks or other defects; S6. Welding: adjust the tungsten electrode extension length according to the weld layer, select the welding current according to the wire diameter and pipe wall thickness, and maintain the temperature range within the appropriate range for welding.

2. The welding method of the fuel supply pipeline according to claim 1, characterized in that: In the step S1, the first pipe section and the second pipe section are both made of stainless steel, and the wall thickness of the first pipe section and the second pipe section is 3 mm to 6 mm; The material of the welding wire is the same as or compatible with the material of the first pipe section and the second pipe section, and the diameter of the welding wire is 2 mm or 2.4 mm.

3. The welding method of the fuel supply pipeline according to claim 1, characterized in that: In step S2, the preset groove size includes: The shape of the preset groove is V-shaped; The opening angle on the single-side bevel is 30°±5°; The blunt edge thickness of the single-sided bevel is 0.8 mm to 1.2 mm; The cleaning welding wire and the forming groove and the processing residues within a certain range around them include: Use a stainless steel brush and / or a cloth soaked in acetone to clean the burrs, debris, oxides and oil stains remaining after processing on the forming groove and the area within 20 mm.

4. The welding method for a fuel supply pipeline according to claim 1, characterized in that: In the step S3, the spacing of the assembly gap is 1.5 mm to 3 mm.

5. The welding method for a fuel supply pipeline according to claim 1, characterized in that: In step S4, the plugging includes plugging with a sponge or a material that does not corrode the materials of the first pipe section and the second pipe section; The gas flow rate of the argon gas is controlled within the range of 10 to 15 L / min, and at the same time, the air in the gas delivery pipe is removed for 1 to 2 minutes.

6. The welding method for a fuel supply pipeline according to claim 1, characterized in that: In the step S5, the length of the spot welding seam is less than 10 mm.

7. The welding method for a fuel supply pipeline according to claim 1, characterized in that: In the step S6, during welding, the extension length of the tungsten electrode is adjusted to 2 mm to 5 mm, and the welding current is set to 70A to 200A.

8. The welding method for a fuel supply pipeline according to claim 7, characterized in that: In step S6, when welding multiple layers, the interlayer temperature of the multiple layers is set to be less than 60°.

9. The welding method for a fuel supply pipeline according to claim 8, characterized in that: In the step S6, after welding, the residual height values ​​of the front and back surfaces of the weld are h, and 0mm≤h≤2mm.

10. The welding method of the fuel supply pipeline according to claim 1, characterized in that: The welding step further comprises: S7. Clean up after welding, clean the weld and surrounding processing residues, and perform RT non-destructive testing.

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