A method of additive manufacturing of an oil and gas transmission steel pipe end

Abstract

The application discloses an additive manufacturing method for a pipe end of an oil and gas conveying steel pipe, and the method comprises the following steps of: S1, polishing the weld reinforcement of the steel pipe, placing the steel pipe on a rotating mechanism, rotating the steel pipe at a constant speed, and polishing the weld reinforcement of the steel pipe; S2, cleaning the pipe end of the steel pipe, including cleaning surface oil stains, rust and oxides, until the surface appears metallic luster; S3, performing submerged arc surfacing to add steel pipes on the outer surface of the pipe end; and S4, processing the inner surface and the outer surface of the pipe end of the steel pipe. The method has the advantages that the pipe end of the steel pipe is thickened by using the submerged arc surfacing additive manufacturing method, the production efficiency is high, the welding quality is good, the performance of the additive manufacturing part is uniform and stable, the pipe end of the steel pipe thickened by the surfacing additive manufacturing is processed by turning, the roundness, the circumference difference and the wall thickness size precision of the pipe end are effectively improved, the stress concentration is reduced, and the service safety and reliability of the steel pipe are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to an oil and gas conveying steel pipe, in particular to an additive manufacturing method for the pipe end of an oil and gas conveying steel pipe, and belongs to the technical field of oil and gas conveying. BACKGROUND

[0002] With the large use of oil and gas conveying steel pipes, the safety requirements for oil and gas pipelines are higher and higher, and higher requirements are put forward for pipeline products and pipeline construction. At present, the welding seam cladding metal strength is significantly higher than that of the base metal in the engineering, which improves the carrying capacity of the girth weld, but due to the excessively high strength, residual stress or strain easily exists in the girth weld and the surrounding area, and under the action of external force in the service process of the steel pipe, stress and strain concentration phenomenon occurs, which further causes pipeline failure and causes huge economic and property losses. The existing oil and gas conveying steel pipe manufacturing method has the following disadvantages: the pipe end is formed by hot working process, the steel pipe organization is affected by the heat treatment process, and the uneven distribution of the organization performance is easy to appear; the pipe end is not mechanically processed, and the roundness, wall thickness, circumference and other parameters are difficult to guarantee. SUMMARY

[0003] In order to overcome the uneven distribution of the organization performance of the existing oil and gas conveying pipe, the roundness, wall thickness, circumference and other parameters of the pipe end are difficult to guarantee, the present application provides an additive manufacturing method for the pipe end of an oil and gas conveying steel pipe.

[0004] The technical scheme adopted by the present application to solve its technical problems is: an additive manufacturing method for the pipe end of an oil and gas conveying steel pipe, including a completed welding steel pipe, and the steps are:

[0005] S1, polishing the excess height of the steel pipe welding seam

[0006] The steel pipe is placed on the rotating mechanism, the steel pipe is rotated, and the excess height of the steel pipe welding seam is polished.

[0007] S2, cleaning the pipe end of the steel pipe

[0008] The pipe end of the steel pipe is cleaned, including cleaning surface oil, rust and oxides, until the surface appears metallic luster.

[0009] S3, submerged arc welding additive steel pipe end outer surface

[0010] The welding wire component and mass percentage used in the submerged arc welding 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, the rest is Fe and unavoidable impurities.

[0011] S4, machining the inner and outer surfaces of the pipe end of the steel pipe.

[0012] In the step S3 of performing submerged arc welding, the diameter of the welding wire is 4.0 mm, the power polarity is 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 step S3 of performing submerged arc welding, the diameter of the welding wire is 4.0 mm, the power polarity is 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.

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

[0015] The steel pipe rotates to complete the first 360° circumferential welding of the steel pipe at the pipe end;

[0016] Then, the steel pipe moves horizontally along the axial direction, and the steel pipe rotates to complete the second 360° circumferential laying welding of the steel pipe;

[0017] Then, the steel pipe moves horizontally along the axial direction, and the steel pipe rotates to complete the third 360° circumferential laying welding of the steel pipe;

[0018] The second and third 360° circumferential welding processes are repeated until the laying layer welding in the designed length is completed.

[0019] Further, the thickness of the laying layer is 1-5 mm.

[0020] S3-2, overlay welding: after the laying welding is completed, the steel pipe moves axially to the initial position close to the laying welding, the position of the welding wire is fixed,

[0021] The steel pipe rotates to complete the first 360° circumferential overlay welding of the steel pipe at the joint between the first and second laying welds;

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

[0023] Then, the steel pipe moves horizontally along the axial direction, and the steel pipe rotates to complete the third 360° circumferential overlay welding of the steel pipe;

[0024] The second and third overlay welding processes are repeated until the overlay layer welding in the designed length is completed, and the thickness requirement of the overlay welding additive process design is met.

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

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

[0027] The overlay welding and the build-up welding adopt a laser tracking mode or a manual adjustment mode, and the first layer of build-up welding covers the overlay welding seam, the second layer of build-up welding covers the first layer of build-up welding seam, and the build-up welding layer covers the first layer of build-up welding seam.

[0028] The submerged arc build-up welding length of the steel pipe end is less than or equal to 500 mm.

[0029] In the step 2, the cleaning length of the steel pipe end is less than or equal to 600 mm.

[0030] In the step S4 of machining the inner surface of the steel pipe end, the turning speed is 100-400 m / min, the feed amount is 0.5-3 mm / r, the cutting depth is 1-3 mm, the axial cutting length is less than or equal to 250 mm, and the transition angle A of the cutting surface is greater than or equal to 120°.

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

[0032] The build-up welding thickness is 20%-100% of the wall thickness of the steel pipe.

[0033] The beneficial effects of the present application are that the steel pipe end is thickened by the submerged arc build-up welding, the production efficiency is high, the welding quality is good, the performance of the build-up welding part is uniform and stable, the steel pipe end thickened by the build-up welding is machined by turning, the roundness, the circumference difference and the wall thickness size precision of the pipe end are effectively improved, the stress concentration is reduced, and the service safety and reliability of the steel pipe are improved. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a flow chart of the oil and gas conveying steel pipe end build-up manufacturing method of the present application.

[0035] Figure 2 is a schematic diagram of the build-up welding seam stacking mode of the present application.

[0036] Figure 3 is a schematic diagram of the build-up welding cross-sectional structure of the present application.

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

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

[0039] The present application will be further described below in combination with the drawings and examples. However, those skilled in the art should know that the present application is not limited to the specific embodiments listed, and as long as it conforms to the spirit of the present application, it should be included in the protection scope of the present application.

[0040] In the description of the present application, it should be noted that the terms "vertical", "upper", "lower", "left", "right", "horizontal" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description or simplification of the description of the present application, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0041] Referring to the accompanying drawings Figure 1 The present application is an additive manufacturing method for the pipe end of an oil and gas conveying steel pipe, comprising a steel pipe 1, and the steps are as follows:

[0042] S1, polishing the excess height of the weld of the steel pipe;

[0043] S2, cleaning the pipe end of the steel pipe;

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

[0045] S4, processing the inner and outer surfaces of the pipe end of the steel pipe.

[0046] Referring to the accompanying drawings Figures 2-4 The additive manufacturing method for the pipe end of an oil and gas conveying steel pipe according to the present application is as follows:

[0047] S1, polishing the excess height of the weld of the steel pipe

[0048] The steel pipe is placed on a rotating mechanism, and the steel pipe is rotated at a uniform speed to polish the excess height of the weld of the steel pipe; it is ensured that the steel pipe will not jump during rotation.

[0049] S2, cleaning the pipe end of the steel pipe

[0050] The pipe end of the steel pipe is cleaned, including cleaning surface oil stains, rust and oxides, until the surface appears metallic luster; the cleaning methods include but are not limited to polishing, polishing and the like.

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

[0052] S3, submerged arc welding to add the outer surface of the pipe end of the steel pipe

[0053] The welding wire material used in the submerged arc welding additive is low-carbon alloy steel, and the components and mass percentages are as follows: 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 is Fe and unavoidable impurities.

[0054] In the submerged arc surfacing, the diameter of the welding wire is 4.0 mm, the power polarity is 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 additive includes a first layer of the surfacing layer 2 and two or more layers of the overlaying layer 3 on the surface of the steel pipe, the temperature of the inner wall of the steel pipe is 100-200 ℃ at the beginning of each layer of the overlaying, and the temperature between the layers in the overlaying process is controlled to prevent the deterioration of the performance of the base material due to the excessively high temperature of the base material of the steel pipe.

[0056] In the surfacing additive operation,

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

[0058] The steel pipe rotates to complete the first 360° circumferential surfacing welding of the steel pipe from the pipe end;

[0059] Then, the steel pipe moves horizontally along the axis, rotates, and completes the second 360° circumferential surfacing welding of the steel pipe;

[0060] Then, the steel pipe moves horizontally along the axis, rotates, and completes the third 360° circumferential surfacing welding of the steel pipe;

[0061] The second and third surfacing welding processes are repeated until the surfacing layer 2 welding in the designed length is completed.

[0062] S3-2, overlaying: after the surfacing is completed, the steel pipe moves axially to the initial position close to the surfacing, the position of the welding wire is fixed,

[0063] The steel pipe rotates to complete the first 360° circumferential overlaying welding of the steel pipe at the joint between the first and second surfacing;

[0064] Then, the steel pipe moves horizontally along the axis, rotates, and completes the second 360° circumferential overlaying welding of the steel pipe;

[0065] Then, the steel pipe moves horizontally along the axis, rotates, and completes the third 360° circumferential overlaying welding of the steel pipe;

[0066] The second and third 360° circumferential overlaying processes of the steel pipe are repeated until the overlaying layer 3 welding in the designed length is completed, and the thickness requirement of the surfacing additive process design is achieved.

[0067] Preferably, the thickness of the surfacing layer is 1-5 mm, and the thickness of each layer of the overlaying is 1-5 mm.

[0068] The surfacing and overlaying adopt a laser tracking mode or a manual adjustment mode to control the first layer of the overlaying to cover the surfacing weld, the second layer of the overlaying to cover the first layer of the overlaying weld, and the overlaying layers to cover the welds in the same way.

[0069] S4, machining the inner surface and the outer surface of the pipe end of the steel pipe

[0070] In the process of turning the inner surface of the pipe end of the steel pipe, 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] In the process of turning the outer surface of the pipe end of the steel pipe, 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] Further, the overlaying additive thickness is 20%-100% of the wall thickness of the steel pipe.

[0073] Further, the overlaying and stacking manner can be flat laying or stacking (for example, Figure 2 As shown in the figure, 2a is flat laying, and 2b is stacking).

[0074] Embodiment:

[0075] The steel pipe 1 is subjected to additive manufacturing by submerged arc welding process, the size of the steel pipe is φ1219×18.4 mm, the additive length is 150 mm, and the wall thickness of the pipe end of the steel pipe after additive manufacturing is 22 mm.

[0076] The components and mass percentages of the base material of the steel pipe 1 are as follows: 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 is Fe and inevitable impurities.

[0077] The components and mass percentages of the welding wire used in the submerged arc welding are as follows: 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 is Fe and inevitable impurities.

[0078] The welding wire is combined with the basic welding agent SJ102G (basicity 1.5-1.9), and the welding process parameters for trial production of submerged arc welding are as follows: welding current 550 A, welding voltage 40 V, and welding speed 0.66 m / min; at the beginning of each stacking, the temperature of the inner wall of the steel pipe is 120-150℃.

[0079] The specific process of the submerged arc welding additive manufacturing is as follows:

[0080] S1, grinding the excess height of the weld of the steel pipe

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

[0082] S2, cleaning the pipe end of the steel pipe

[0083] The surface of the pipe end of the steel pipe is cleaned by polishing to remove oil stains, rust and oxides until a metallic luster appears on the surface. The cleaning length is 250 mm.

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

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

[0086] S3-2, overlay welding, the thickness of each layer of overlay welding is 2-3 mm, a total of 4 layers of overlay welding are performed to achieve the thickness requirement of the welding additive process design.

[0087] S4, machining the inner and outer surfaces of the pipe end of the steel pipe

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

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

[0090] The pipe end of the steel pipe is submerged arc welding additive by the additive manufacturing method for the pipe end of the oil and gas transmission steel pipe, and the appearance forming quality of the welded joint of the steel pipe after additive manufacturing is good. After turning the steel pipe after the welding additive is completed, the wall thickness of the pipe end of the steel pipe reaches 22 mm.

[0091] Tables 1, 2 and 3 are the mechanical properties of the steel pipe after welding additive of the examples.

[0092] Table 1 impact property of the steel pipe after welding additive (-10℃)

[0093]

[0094] Table 2 tensile property of the steel pipe before and after welding / MPa

[0095]

[0096] Table 3 tensile force of the steel pipe before and after welding / kN

[0097]

[0098] The oil and gas conveying steel pipe end additive manufacturing method is simple and reliable, high in production efficiency, capable of guaranteeing the roundness, circumference difference and wall thickness of the steel pipe end through turning processing, improving the carrying capacity of the joint at the connecting ring weld of the steel pipe through the increase of the thickness of the steel pipe end, and improving the safety and reliability of the oil and gas conveying pipeline.

[0099] It should be noted that the above examples are examples rather than limiting the present application, and those skilled in the art will be able to design many alternative embodiments without departing from the scope of the claims of the present patent.

Claims

1. A method for additive manufacturing of the ends of an oil and gas transmission steel pipe, comprising a welded steel pipe, the steps of which are: S1. Grinding the excess height of the steel pipe weld. The steel pipe is placed on the rotating mechanism, and the steel pipe rotates to grind the excess height of the weld seam. S2. Clean the ends of the steel pipe. Clean the ends of the steel pipe, including removing surface oil, rust and oxides, until the surface has a metallic luster; S3, Submerged arc welding of additive steel pipe end outer surface The welding wire composition and mass percentage used in the submerged arc welding are as follows: 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%, with the remainder being Fe and unavoidable impurities; S4. Machining the inner and outer surfaces of the steel pipe ends, wherein the machining is a turning process; When performing submerged arc welding in step S3, the welding wire diameter is 4.0 mm, the power supply polarity is DC positive, 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. In the additive manufacturing process of step S3, S3-1, Welding: The position of the welding wire is fixed. The steel pipe is rotated to complete the first 360° circumference welding of the steel pipe, starting from the pipe end. After that, the steel pipe moves horizontally along the axis and rotates to complete the second 360° circumferential welding of the steel pipe. Then, the steel pipe moves horizontally along the axis and rotates to complete the third 360° circumferential welding of the steel pipe. Repeat the second and third 360° circumferential welding process of the steel pipe until the weld layer within the designed length is completed. The thickness of the weld layer is 1-5 mm; S3-2, Overlap Welding: After the overlay welding is completed, the steel pipe is moved axially to a position close to the initial position of the overlay welding, and the position of the welding wire is fixed. The steel pipe is rotated, and the first steel pipe circumference 360° lap welding is completed at the junction of the first and second lap welds. After that, the steel pipe moves horizontally along the axis and rotates to complete the second 360° circumferential lap welding of the steel pipe. Then, the steel pipe moves horizontally along the axis and rotates to complete the third 360° circumferential lap welding of the steel pipe. Repeat the second and third overlay welding process until the overlay layer within the designed length is completed, achieving the thickness requirements of the overlay additive manufacturing process. The thickness of each layer of the lap weld is 1-5 mm; At the start of each layer of welding, the temperature of the inner wall of the steel pipe is 100-200℃; The laying and overlapping welding are controlled by laser tracking or manual adjustment, so that the first layer of overlapping welding covers the laying weld, the second layer of overlapping welding covers the first layer of overlapping weld, and so on.

2. The additive manufacturing method for the ends of oil and gas transmission steel pipes according to claim 1, characterized in that: The length of the submerged arc welding additive material at the end of the steel pipe is ≤500mm.

3. The additive manufacturing method for the ends of oil and gas transmission steel pipes according to claim 1, characterized in that: In step 2, the length of the steel pipe end cleaning is ≤600 mm.

4. The additive manufacturing method for the ends of oil and gas transmission steel pipes according to claim 1, characterized in that: in When machining 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 depth of cut is 1-3 mm, the axial cutting length is ≤250 mm, and the transition angle A of the cutting surface is ≥120°.

5. The additive manufacturing method for the pipe ends of oil and gas transmission steel pipes according to claim 4, characterized in that: in When machining 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 depth of cut is 1.5-3 mm.

6. The additive manufacturing method for the ends of oil and gas transmission steel pipes according to claim 1, characterized in that: The thickness of the weld overlay is 20% to 100% of the steel pipe wall thickness.

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