Additive manufacturing method for pipe end of oil and gas conveying steel pipe

Abstract

The pipe end additive manufacturing method for the oil and gas conveying steel pipe comprises a welded steel pipe and comprises the steps that S1, the excess weld metal of a steel pipe welding seam is polished, specifically, the steel pipe is placed on a rotating mechanism and rotates at a constant speed, and the excess weld metal of the steel pipe welding seam is polished; s2, the pipe end of the steel pipe is cleaned, specifically, surface oil dirt, rust and oxide are cleaned till the surface has metallic luster; s3, the outer surface of the pipe end of the additive steel pipe is subjected to submerged arc surfacing; and S4, the inner surface and the outer surface of the steel pipe end are machined. The method has the beneficial effects that the end part of the steel pipe is thickened in a submerged arc surfacing additional material mode, the production efficiency is high, the welding quality is good, and the performance of the additional material part is uniform and stable; the pipe end of the surfacing additive thickened steel pipe is turned, so that the roundness, perimeter difference and wall thickness size precision of the pipe end are effectively improved, stress concentration is reduced, and the service safety and reliability of the steel pipe are improved.

Description

Technical Field

[0001] The invention relates to an oil and gas transportation steel pipe, in particular to an oil and gas transportation steel pipe end additive manufacturing method, belonging to the technical field of oil and gas transportation. Background Art

[0002] With the extensive use of oil and gas transmission steel pipes, the safety requirements for oil and gas pipelines are becoming increasingly higher, and higher requirements are being placed on pipeline products and pipeline construction. At present, the weld cladding metal strength commonly used in engineering is significantly higher than the parent material to increase the bearing capacity of the girth weld. However, due to the excessive strength, residual stress or strain is very likely to exist in the girth weld and a certain area around it. Under the action of external forces during the service of the steel pipe, stress and strain concentration occurs, which in turn causes pipeline failure and causes huge economic and property losses. The existing method for manufacturing oil and gas transmission steel pipes has the following shortcomings: the pipe end adopts a hot processing forming process, and the steel pipe structure is affected by the heat treatment process, which is prone to uneven distribution of organizational properties; the pipe end is not machined, and parameters such as roundness, wall thickness, and circumference are difficult to guarantee. Summary of the invention

[0003] In order to overcome the problems of uneven distribution of steel pipe organizational properties and difficulty in ensuring the roundness, wall thickness, circumference, etc. of the pipe ends of existing oil and gas transmission pipes, the present invention provides an additive manufacturing method for the pipe ends of oil and gas transmission steel pipes.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a method for additive manufacturing of the end of an oil and gas transmission steel pipe, comprising a welded steel pipe, the steps of which are:

[0005] S1. Grinding the weld height of steel pipe

[0006] The steel pipe is placed on the rotating mechanism, the steel pipe is rotated, and the excess height of the steel pipe weld is ground.

[0007] S2. Clean the steel pipe ends

[0008] Clean the ends of the steel pipes, including removing surface oil, rust and oxides, until a metallic luster appears on the surface.

[0009] S3, Submerged arc cladding welding of the outer surface of the steel pipe end

[0010] The welding wire components and mass percentages used in the submerged arc cladding are: C 0.03%-0.15%, Mn 0.6%-2.0%, Si 0.1%-0.4%, Mo≤0.6%, Ni≤0.6%, Cu≤0.3%, Cr≤0.5%, S≤0.01, P≤0.1, B≤0.003, and the rest are Fe and unavoidable impurities.

[0011] S4. Process the inner and outer surfaces of the steel pipe ends.

[0012] When performing submerged arc cladding in step S3, the diameter of the welding wire is 4.0 mm, the polarity of the power supply adopts direct current positive connection, the welding current is 500-800 A, the welding voltage is 38-44 V, and the welding speed is 0.4-1.0 m / min.

[0013] In the surfacing welding process of step S3,

[0014] S3-1, laying welding: the welding wire position is fixed,

[0015] The steel pipe is rotated to complete the first 360° welding of the steel pipe circumference starting from the pipe end;

[0016] After that, the steel pipe is moved horizontally along the axial direction and rotated to complete the second 360° circumferential welding of the steel pipe;

[0017] Then, the steel pipe is moved horizontally along the axial direction and rotated to complete the third 360° circumferential welding of the steel pipe;

[0018] Repeat the second and third 360° welding process of the steel pipe circumference until the welding of the welding layer within the designed length is completed.

[0019] Furthermore, the thickness of the welding layer is 1-5 mm.

[0020] S3-2, stitch welding: After the stitch welding is completed, the steel pipe is moved axially to the initial position close to the stitch welding, and the welding wire position is fixed.

[0021] The steel pipe is rotated to complete the 360° lap welding of the first steel pipe at the joint of the first and second lap welding;

[0022] Afterwards, the steel pipe moves horizontally along the axial direction and rotates to complete the second 360° lap welding of the steel pipe;

[0023] Then, the steel pipe is moved horizontally along the axial direction and rotated to complete the third 360° lap welding of the steel pipe;

[0024] Repeat the second and third suture welding processes until the suture welding layer within the designed length is completed and the thickness requirement of the surfacing additive process design is met.

[0025] Furthermore, the thickness of each layer of the stitch welding is 1-5 mm.

[0026] At the beginning of each layer of lap welding, the inner wall temperature of the steel pipe is 100-200℃.

[0027] The layer welding and the stack welding adopt a laser tracking method or a manual adjustment method to control the first layer of stack welding to cover the layer welding seam, the second layer of stack welding to cover the first layer of stack welding seam, and so on.

[0028] The length of the steel pipe end submerged arc cladding material addition is ≤500mm.

[0029] In step 2, the cleaning length of the steel pipe end is ≤600 mm.

[0030] When processing the inner surface of the steel pipe end in step S4, the turning speed is 100-400 m / min, the feed rate is 0.5-3 mm / r, the cutting depth is 1-3 mm, the axial cutting length is ≤250 mm, and the transition angle A of the cutting surface is ≥120°.

[0031] When processing the outer surface of the steel pipe end in step S4, the turning speed is 150-450 m / min, the feed rate is 1-5 mm / r, and the cutting depth is 1.5-3 mm.

[0032] The thickness of the surfacing material is 20% to 100% of the wall thickness of the steel pipe.

[0033] The beneficial effects of the present invention are that the end of the steel pipe is thickened by submerged arc surfacing, which has high production efficiency, good welding quality, and uniform and stable performance of the additive part; the end of the steel pipe thickened by surfacing is processed by turning, which effectively improves the roundness, circumference difference and wall thickness dimensional accuracy of the pipe end, reduces stress concentration, and improves the safety and reliability of the steel pipe in service. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a flow chart of the additive manufacturing method for the pipe end of an oil and gas transmission steel pipe of the present invention.

[0035] Figure 2 It is a schematic diagram of the stacking method of the cladding weld of the present invention.

[0036] Figure 3 It is a schematic diagram of the cross-sectional structure of the surfacing welding of the present invention.

[0037] Figure 4 It is a schematic diagram of the cross-sectional structure of the oil and gas transmission pipe of the present invention.

[0038] In the figure: 1. steel pipe, 2. welding layer, 3. overlapping welding layer, 4. overlay welding layer. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. However, those skilled in the art should be aware that the present invention is not limited to the specific embodiments listed, and all embodiments should be included in the protection scope of the present invention as long as they conform to the spirit of the present invention.

[0040] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "left", "right", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing or simplifying the description of the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] See attached Figure 1 The present invention provides a method for additive manufacturing of an oil and gas transmission steel pipe end, comprising a steel pipe 1, and the steps are:

[0042] S1. Grind the weld height of the steel pipe;

[0043] S2. Clean the ends of the steel pipe;

[0044] S3, submerged arc cladding welding of the outer surface of the steel pipe end;

[0045] S4. Process the inner and outer surfaces of the steel pipe ends.

[0046] See attached Figure 2-4 The invention discloses a method for additive manufacturing of a steel pipe end for oil and gas transportation as follows:

[0047] S1. Grinding the weld height of steel pipe

[0048] Place the steel pipe on the rotating mechanism, rotate the steel pipe at a uniform speed, and grind the excess height of the steel pipe weld to ensure that the steel pipe does not jump during the rotation process.

[0049] S2. Clean the steel pipe ends

[0050] Clean the ends of the steel pipes, including cleaning the surface oil, rust and oxides until a metallic luster appears on the surface; cleaning methods include but are not limited to grinding and polishing.

[0051] Preferably, the cleaning length of the steel pipe end is ≤600mm, and the submerged arc cladding length of the steel pipe end is ≤500mm. Usually, the cleaning length is about 100mm greater than the additive length.

[0052] S3, Submerged arc cladding welding of the outer surface of the steel pipe end

[0053] The welding wire used in the submerged arc surfacing additive is made of low-carbon alloy steel, and its components and mass percentages are: C 0.03%-0.15%, Mn 0.6%-2.0%, Si 0.1%-0.4%, Mo≤0.6%, Ni≤0.6%, Cu≤0.3%, Cr≤0.5%, S≤0.01, P≤0.1, B≤0.003, and the rest are Fe and unavoidable impurities.

[0054] When performing submerged arc cladding, the diameter of the welding wire is 4.0 mm, the power polarity adopts direct current positive connection, the welding current is 500-800 A, the welding voltage is 38-44 V, and the welding speed is 0.4-1.0 m / min.

[0055] The surfacing material includes a first welding layer 2 and two or more suture welding layers 3 on the surface of the steel pipe. At the beginning of each suture welding, the inner wall temperature of the steel pipe is 100-200°C. Controlling the interlayer temperature during the suture welding process can prevent the performance of the base material of the steel pipe from being deteriorated due to the excessively high temperature of the base material.

[0056] In the cladding process,

[0057] S3-1, laying welding: the welding wire position is fixed,

[0058] The steel pipe is rotated to complete the first 360° welding of the steel pipe circumference starting from the pipe end;

[0059] After that, the steel pipe is moved horizontally along the axial direction and rotated to complete the second 360° circumferential welding of the steel pipe;

[0060] Then, the steel pipe is moved horizontally along the axial direction and rotated to complete the third 360° circumferential welding of the steel pipe;

[0061] Repeat the second and third welding processes until the welding of the welding layer 2 within the designed length is completed.

[0062] S3-2, stitch welding: After the stitch welding is completed, the steel pipe is moved axially to the initial position close to the stitch welding, and the welding wire position is fixed.

[0063] The steel pipe is rotated to complete the 360° lap welding of the first steel pipe at the joint of the first and second lap welding;

[0064] Afterwards, the steel pipe moves horizontally along the axial direction and rotates to complete the second 360° lap welding of the steel pipe;

[0065] Then, the steel pipe is moved horizontally along the axial direction and rotated to complete the third 360° lap welding of the steel pipe;

[0066] Repeat the second and third 360° lap welding process of the steel pipe circumference until the lap welding layer 3 within the designed length is completed and the thickness requirement of the cladding additive process design is met.

[0067] Preferably, the thickness of the weld layer is 1-5 mm; the thickness of each stack weld layer is 1-5 mm.

[0068] The layer welding and the stack welding adopt a laser tracking method or a manual adjustment method to control the first layer of stack welding to cover the layer welding seam, the second layer of stack welding to cover the first layer of stack welding seam, and so on.

[0069] S4. Processing the inner and outer surfaces of steel pipe ends

[0070] When turning the inner surface of the steel pipe end, the turning speed is 100-400 m / min, the feed rate is 0.5-3 mm / r, the cutting depth is 1-3 mm, the axial cutting length is ≤250 mm, and the transition angle A of the cutting surface is ≥120°.

[0071] When turning the outer surface of the steel pipe end, the turning speed is 150-450 m / min, the feed rate is 1-5 mm / r, and the cutting depth is 1.5-3 mm.

[0072] Furthermore, the thickness of the surfacing material is 20% to 100% of the wall thickness of the steel pipe.

[0073] Furthermore, the laying welding and overlapping welding can be flat laying or overlapping (such as Figure 2 As shown, 2a is flat laying and 2b is overlapping).

[0074] Example:

[0075] The steel pipe 1 is subjected to material augmentation by using a submerged arc surfacing process. The size of the steel pipe is φ1219×18.4 mm, the augmentation length is 150 mm, and the wall thickness of the steel pipe end after the augmentation is 22 mm.

[0076] The components and mass percentages of the base material of the steel pipe 1 are: C 0.05%, Mn 1.73%, Si 0.19%, P 0.008%, S 0.002%, Mo 0.11%, Ni 0.14%, Cr 0.21%, Nb 0.055%, Ti 0.012%, B 0.0003%, and the rest are Fe and unavoidable impurities.

[0077] The welding wire components and mass percentages used in the submerged arc cladding are: C 0.05%, Mn 1.53%, Si 0.19%, Mo 0.34%, Ni 0.2%, Cu 0.02%, Cr 0.40%, S 0.008, P 0.014, B 0.0026, and the rest are Fe and unavoidable impurities.

[0078] Using welding wire combined with alkaline flux SJ102G (basicity 1.5-1.9), the submerged arc cladding trial welding process parameters are: welding current 550A, welding voltage 40V, welding speed 0.66m / min; at the beginning of each cladding, the inner wall temperature of the steel pipe is 120-150℃.

[0079] The specific process of submerged arc cladding is as follows:

[0080] S1. Grinding the weld height of steel pipe

[0081] The steel pipe 1 is placed on the rotating mechanism, the steel pipe rotates at a uniform speed, and the excess height of the weld of the steel pipe is polished to ensure that the steel pipe does not jump during the rotation process.

[0082] S2. Clean the steel pipe ends

[0083] The surface oil, rust and oxides of the steel pipe end are cleaned by grinding until the surface has a metallic luster. The cleaning length is 250mm.

[0084] S3, Submerged arc welding of the outer surface of the steel pipe end

[0085] S3-1, welding, the thickness of the welding layer is 2-3mm.

[0086] S3-2, stack welding, the thickness of each layer is 2 to 3 mm, and there are 4 layers of stack welding in total, which meets the thickness requirements of the cladding additive process design.

[0087] S4. Processing the inner and outer surfaces of steel pipe ends

[0088] When turning the inner surface of the steel pipe end, the turning speed is 240m / min, the feed rate is 1.8mm / r, the cutting depth is 2mm, and the axial cutting length is 100mm, so that the roundness of the inner hole of the steel pipe end meets the design requirements. The transition angle A between the finished surface and the steel pipe after turning is 150°.

[0089] When turning the outer surface of the steel pipe end, the weld overlay 4 is processed with a turning speed of 300 m / min, a feed rate of 3 mm / r, and a cutting depth of 1-4 mm, so that the roundness, wall thickness, and circumference difference of the steel pipe end meet the design requirements.

[0090] The additive manufacturing method for the end of an oil and gas transportation steel pipe of the present invention is adopted to perform submerged arc cladding on the end of the steel pipe. The appearance forming quality of the weld of the steel pipe after cladding is good. The steel pipe after cladding is performed by turning, and the wall thickness of the steel pipe end reaches 22 mm.

[0091] Tables 1, 2 and 3 show the mechanical properties of the steel pipes after cladding and material addition in the examples.

[0092] Table 1 Impact properties of steel pipe after surfacing (-10℃)

[0093]

[0094] Table 2 Tensile properties of steel pipe before and after surfacing / MPa

[0095]

[0096] Table 3 Tensile force of steel pipe before and after surfacing / kN

[0097]

[0098] The invention discloses an additive manufacturing method for an oil and gas transportation steel pipe end, which is simple, reliable and has high production efficiency. The roundness, circumference difference and wall thickness of the steel pipe end can be guaranteed through turning processing. The thickness of the steel pipe end is increased to improve the bearing capacity of the joint at the steel pipe connecting ring weld, thereby improving the safety and reliability of the oil and gas transportation pipeline.

[0099] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the claims of this patent.

Claims

1. A method for additive manufacturing of an oil and gas transmission steel pipe end, comprising a welded steel pipe, the steps of which are: S1. Grinding the weld height of steel pipe The steel pipe is placed on the rotating mechanism, the steel pipe is rotated, and the excess height of the steel pipe weld is ground; S2. Clean the steel pipe ends Clean the ends of the steel pipes, including removing surface oil, rust and oxides, until the surface shows metallic luster; S3, Submerged arc cladding welding of the outer surface of the steel pipe end The welding wire components and mass percentages used in the submerged arc cladding are: C 0.03%-0.15%, Mn 0.6%-2.0%, Si 0.1%-0.4%, Mo≤0.6%, Ni≤0.6%, Cu≤0.3%, Cr≤0.5%, S≤0.01, P≤0.1, B≤0.003, and the rest are Fe and unavoidable impurities; S4. Process the inner and outer surfaces of the steel pipe ends.

2. The method for additive manufacturing of the end of a steel pipe for oil and gas transportation according to claim 1 is characterized in that: When performing submerged arc cladding welding in step S3, the diameter of the welding wire is 4.0 mm, the polarity of the power supply adopts direct current positive connection, the welding current is 500-800 A, the welding voltage is 38-44 V, and the welding speed is 0.4-1.0 m / min.

3. The method for additive manufacturing of the end of a steel pipe for oil and gas transportation according to claim 2 is characterized in that: In the surfacing welding and material adding operation of step S3, S3-1, laying welding: the welding wire position is fixed, The steel pipe is rotated to complete the first 360° welding of the steel pipe circumference starting from the pipe end; After that, the steel pipe is moved horizontally along the axial direction and rotated to complete the second 360° circumferential welding of the steel pipe; Then, the steel pipe is moved horizontally along the axial direction and rotated to complete the third 360° circumferential welding of the steel pipe; Repeat the second and third 360° welding process of the steel pipe circumference until the welding of the weld layer within the designed length is completed; The thickness of the welding layer is 1-5 mm; S3-2, stitch welding: After the stitch welding is completed, the steel pipe is moved axially to the initial position close to the stitch welding, and the welding wire position is fixed. The steel pipe is rotated to complete the 360° lap welding of the first steel pipe at the joint of the first and second lap welding; Afterwards, the steel pipe moves horizontally along the axial direction and rotates to complete the second 360° lap welding of the steel pipe; Then, the steel pipe is moved horizontally along the axial direction and rotated to complete the third 360° lap welding of the steel pipe; Repeat the second and third suture welding processes until the suture welding layer within the designed length is completed and the thickness requirement of the surfacing additive process design is met; The thickness of each layer of the stitch welding is 1-5 mm.

4. The method for additive manufacturing of the end of a steel pipe for oil and gas transportation according to claim 3 is characterized by: At the beginning of each layer of lap welding, the inner wall temperature of the steel pipe is 100-200℃.

5. The method for additive manufacturing of the end of a steel pipe for oil and gas transportation according to claim 3 or 4, characterized in that: The layer welding and the stack welding adopt a laser tracking method or a manual adjustment method to control the first layer of stack welding to cover the layer welding seam, the second layer of stack welding to cover the first layer of stack welding seam, and so on.

6. The method for additive manufacturing of the end of a steel pipe for oil and gas transportation according to claim 5 is characterized by: The length of the steel pipe end submerged arc cladding material addition is ≤500mm.

7. The method for additive manufacturing of the end of a steel pipe for oil and gas transportation according to claim 1 is characterized by: In step 2, the cleaning length of the steel pipe end is ≤600 mm.

8. The method for additive manufacturing of the end of a steel pipe for oil and gas transportation according to claim 1 is characterized in that: When processing the inner surface of the steel pipe end in step S4, the turning speed is 100-400 m / min, the feed rate is 0.5-3 mm / r, the cutting depth is 1-3 mm, the axial cutting length is ≤250 mm, and the transition angle A of the cutting surface is ≥120°.

9. The method for additive manufacturing of the end of a steel pipe for oil and gas transportation according to claim 8 is characterized in that: When processing the outer surface of the steel pipe end in step S4, the turning speed is 150-450 m / min, the feed rate is 1-5 mm / r, and the cutting depth is 1.5-3 mm.

10. The method for additive manufacturing of the end of a steel pipe for oil and gas transportation according to claim 1, characterized in that: The thickness of the surfacing material is 20% to 100% of the wall thickness of the steel pipe.

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