Reducing sleeve for repairing circumferential weld of pipeline, mold and manufacturing and using methods of reducing sleeve and mold

Abstract

The invention provides a reducing sleeve for repairing a circumferential weld of a pipeline, a mold and a manufacturing and using method. The reducing sleeve for repairing the circumferential weld of the pipeline comprises two sleeve assemblies used for being buckled to the defect position of the circumferential weld between a first pipeline and a second pipeline, the two sleeve assemblies are oppositely buckled and fixed to form the reducing sleeve, and the outer diameter of the first pipeline is larger than that of the second pipeline. A circumferential weld is arranged between the first pipeline and the second pipeline, one end of the reducing sleeve is provided with a first cavity matched with the outer wall of the first pipeline, the other end of the reducing sleeve is provided with a second cavity matched with the second pipeline, and the first cavity and the second cavity have preset lengths; a third cavity used for covering the circumferential weld is formed in the middle of the reducing sleeve.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline repair, and in particular to a reducing sleeve for pipeline girth weld repair, a mold, and a manufacturing and use method. Background Art

[0002] At present, among the more than 20 existing pipeline defect repair methods, pipe replacement and B-type sleeve repair are two permanent repair methods that are often used for pipeline defect repair. However, when pipe replacement is used, not only will the entire pipeline be shut down, causing natural gas supply interruption to downstream users, but the natural gas in the dozens of kilometers of pipelines between the two valve chambers where the defective pipeline is located must also be completely emptied, causing huge economic losses. When using the B-type sleeve repair, defects can be repaired without stopping the pipeline, which has the characteristics of low cost, good effect and high reliability. In addition, compared with composite materials, A-type sleeves, epoxy sleeves and other repair methods that can only withstand circumferential loads, the B-type sleeve repair method can not only withstand circumferential loads, but also axial and bending loads. At the same time, since the end of the B-type sleeve is connected to the repaired steel pipe through a circumferential fillet weld, it has good sealing performance and is also suitable for repairing leakage defects that occur during the service of the pipeline. In addition, sleeve repair can completely restore the strength of the damaged pipeline to the minimum yield strength of the pipeline. Among them, the Type A sleeve repair method only surrounds the pipeline and has no sealing effect, while the Type B repair method can repair leaks that occur during the service of the pipeline and maintain the pressure inside the pipeline.

[0003] Traditional B-type sleeves usually include two semi-cylindrical arc plates that are symmetrical in the upper and lower parts. When installing, they first need to be buckled on the upper and lower sides of the steel pipe to be repaired and wrap the defects. Then, two longitudinal welds are used to weld the two semi-cylinders into a complete cylinder. Finally, two circumferential fillet welds are used at the ends of the cylinder to weld the sleeve to the steel pipe to be repaired. It can only be used to repair concentric steel pipe components with the same external contours on both sides of the defect. At present, pipeline girth weld defects mostly exist in welded joints with unequal wall thicknesses, especially in the repair of girth welds with large differences in wall thickness such as the three-way main pipe and the trunk steel pipe, the induction heating elbow and the trunk steel pipe in the pipeline system. The maximum misalignment of the welding joint of the three-way main pipe measured on site is 31mm, and the traditional B-type sleeve cannot be installed. At present, the main idea for manufacturing reducing sleeves is to use thick-walled steel pipes for cutting and other machining methods to manufacture sleeves with shapes that meet on-site applications. However, there are two problems: first, the machining method destroys the thermal processing streamlines of metal products and reduces the overall mechanical properties of the product; second, the sleeve manufactured by this method can only repair a limited amount of misalignment in the pipe, which cannot meet the repair needs of pipes with larger wall thickness differences. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a reducing sleeve for repairing pipeline girth welds, a mold, and a manufacturing and using method thereof in view of the deficiencies in the prior art.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: A reducing sleeve for repairing a pipeline girth weld, comprising: two sleeve assemblies for interlocking at a defective position of a girth weld between a first pipeline and a second pipeline, the two sleeve assemblies are relatively buckled and fixed to form a reducing sleeve, the outer diameter of the first pipeline is greater than the outer diameter of the second pipeline, a girth weld is provided between the first pipeline and the second pipeline, one end of the reducing sleeve is provided with a first cavity adapted to the outer wall of the first pipeline, the other end of the reducing sleeve is provided with a second cavity adapted to the second pipeline, the first cavity and the second cavity both have a preset length, and the middle part of the reducing sleeve is provided with a third cavity for covering the girth weld.

[0006] The beneficial effects of the technical solution of the present invention are: the designed sleeve cavity is relatively large and can cover the requirements of different welding joint excess heights. The two ends of the sleeve and the fitting area of ​​the steel pipe have a certain length, and the inner and outer diameters can be cut according to the actual size of the steel pipe to be repaired, which is convenient for actual assembly and application. It can meet the needs of repairing girth weld defects in pipelines with large wall thickness differences, and the greater the wall thickness difference, the more significant the technical advantage. It solves the problem that it is difficult to directly repair and reinforce girth welds in the prior art. The sleeve is used to be sleeved on the outside of the girth weld, which can meet the in-service repair and reinforcement of girth weld defects between the main pipes of pipelines with unequal wall thicknesses and the butt steel pipes without stopping the oil and gas transmission medium in the pipeline. The improved reducer plus straight pipe section comprehensive structure method not only overcomes the problem of not being able to directly perform welding repairs, but also uses this structure to achieve reinforcement of weak areas of the pipeline structure, and can achieve non-stop welding repair of girth weld defects between the main pipe and the butt steel pipe in the in-service pipeline.

[0007] In addition, the present invention also provides a mold for producing a reducing sleeve for repairing a pipeline ring weld as described above, comprising: a mold body, wherein both ends of the mold body are respectively provided with a fourth cavity adapted to the outer wall of a blank steel pipe for forming the reducing sleeve, and the inner diameter of the blank steel pipe is the same as the inner diameter of the third cavity, one end of the mold body is provided with a fifth cavity for producing a reducing sleeve adapted to the outer wall of a first pipe, and the other end of the mold body is provided with a sixth cavity for producing a reducing sleeve adapted to the outer wall of a second pipe, the fifth cavity is connected to the fourth cavity located at one end of the mold body, and the sixth cavity is connected to the fourth cavity located at the other end of the mold body, and the fifth cavity and the sixth cavity both have a preset length.

[0008] The beneficial effects of the technical solution of the present invention are as follows: two parallel cavities are respectively arranged in the center, with diameters D1 and D2 respectively, and with a certain length, which are used to control the outer diameter size of the two ends of the sleeve and have a certain processing allowance. The sixth cavity is used to control the outer diameter of the side with a smaller outer diameter of the sleeve, and the fifth cavity is used to control the outer diameter of the side with a larger outer diameter of the sleeve. The inner diameter size of the entrances at both ends is consistent, and both are adapted to the outer diameter size of the blank steel pipe, which is convenient for the steel pipe to enter and exit during the compression molding process. It can meet the needs of repairing defects in circumferential welds of pipelines with large wall thickness differences, and the greater the wall thickness difference, the more significant the technical advantage. The large and small heads of the sleeve can be processed at both ends of the mold, saving mold costs. The sleeve cavity made by the mold is larger and can cover the requirements of different welding joint excess heights. The two ends of the sleeve have a certain length in the fitting area with the steel pipe. The inner and outer diameters can be cut according to the actual size of the steel pipe to be repaired, which is convenient for actual assembly applications.

[0009] Furthermore, there are smooth transition structures between the fifth cavity and the fourth cavity located at one end of the mold body, and between the sixth cavity and the fourth cavity located at the other end of the mold body.

[0010] The beneficial effects of adopting the above further technical solution are: setting the curve for smooth transition, facilitating metal rheology during hot working, and preventing arbitrary deformation of the sleeve.

[0011] Furthermore, the inner diameter value of the fifth cavity is the sum of the outer diameter of the first pipe and the wall thickness of the blank steel pipe, and the inner diameter value of the sixth cavity is the sum of the outer diameter of the second pipe and the wall thickness of the blank steel pipe.

[0012] The beneficial effect of adopting the above further technical solution is that it is easy to make a sleeve that is compatible with the first pipe and the second pipe through a mold.

[0013] In addition, the present invention also provides a method for manufacturing a reducing sleeve for repairing a pipeline girth weld as described above. Based on the pressure head and the mold as described above, the manufacturing method includes:

[0014] S1, press one end of the blank steel pipe into the fifth cavity of the mold through a pressing head;

[0015] S2. Invert the mold and the blank steel pipe, and press the other end of the blank steel pipe into the sixth cavity of the mold by using a pressing head.

[0016] The beneficial effects of the technical solution of the present invention are as follows: adopting the large head die pressing method of the different diameter sleeve, placing the large end of the mold upward, pressing the blank steel pipe into the mold with the pressure head, controlling the pressing amount, and pressing out the large head (i.e., the end with the larger outer diameter of the sleeve) of the different diameter sleeve. Then adopting the small head die pressing method of the different diameter sleeve, placing the small end of the mold upward, pressing the blank steel pipe into the mold with the pressure head, controlling the pressing amount, and pressing out the small head (i.e., the end with the smaller outer diameter of the sleeve) of the different diameter sleeve.

[0017] Furthermore, before step S1, the following steps are included:

[0018] measuring the outer diameter of the first pipe, the outer diameter of the second pipe, and the height of the girth weld;

[0019] Select a blank steel pipe with an inner diameter greater than the height of the girth weld and measure the wall thickness of the blank steel pipe;

[0020] The mold is selected according to the outer diameter of the first pipe, the outer diameter of the second pipe and the wall thickness of the blank steel pipe.

[0021] The beneficial effect of adopting the above further technical solution is that it is easy to manufacture the sleeve that is compatible with the first pipe and the second pipe, thereby improving the accuracy.

[0022] Further, step S1 includes:

[0023] S11, heating the blank steel pipe to above the austenite temperature;

[0024] S12, pressing one end of the blank steel pipe into the fifth cavity of the mold by a pressing head;

[0025] Step S2 includes:

[0026] S21, heating the blank steel pipe to above the austenite temperature;

[0027] S22, inverting the mold and the blank steel pipe, and pressing the other end of the blank steel pipe into the sixth cavity of the pressing mold by the pressing head.

[0028] The beneficial effect of adopting the above further technical solution is: heating the blank steel pipe to above the austenite temperature, improving the plasticity of the steel pipe, facilitating the pressure forming of the sleeve, and facilitating processing.

[0029] Furthermore, after step S2, the process includes: performing tempering treatment on the rough steel pipe.

[0030] The beneficial effect of adopting the above further technical solution is: eliminating the internal stress of the sleeve.

[0031] Again, the present invention also provides a method for using the reducing sleeve for repairing a pipeline girth weld as described above, comprising:

[0032] S1, cutting the different diameter sleeve into two sleeve assemblies along the horizontal axis;

[0033] S2, wrapping two sleeve assemblies on the pipe to be repaired;

[0034] S3. Weld the longitudinal weld and the circumferential weld separately to repair the pipeline defects.

[0035] The beneficial effect of the technical solution of the present invention is: the different-diameter sleeve is cut into two halves along the horizontal axis, wrapped on the pipe to be repaired, and the longitudinal weld and the circumferential weld are welded respectively, so that the pipe defects can be repaired. Among them, the sleeve cavity is relatively large, which can meet the requirements of different welding joint excess heights. In addition, the two ends of the sleeve have a certain length of the fitting area with the steel pipe, and the inner and outer diameters can be cut according to the actual size of the steel pipe to be repaired, which is convenient for actual assembly and application.

[0036] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic structural diagram of a reducing sleeve provided in an embodiment of the present invention.

[0038] Figure 2 A schematic structural diagram of a mold provided in an embodiment of the present invention.

[0039] Figure 3 One of the structural schematic diagrams of manufacturing a different-diameter sleeve by a mold provided in an embodiment of the present invention.

[0040] Figure 4 The second structural schematic diagram of manufacturing a different-diameter sleeve by a mold provided in an embodiment of the present invention.

[0041] Figure 5 The third structural schematic diagram of the method for manufacturing a sleeve of different diameters by a mold provided in an embodiment of the present invention.

[0042] Figure 6 The fourth structural schematic diagram of the method for manufacturing a sleeve of different diameters by a mold provided in an embodiment of the present invention.

[0043] Figure 7 A schematic flow chart of a method for manufacturing a reducing sleeve by a mold provided in an embodiment of the present invention.

[0044] Figure 8 A schematic flow chart of a method for using a reducing sleeve provided in an embodiment of the present invention.

[0045] Explanation of the accompanying drawings: 1. First pipeline; 2. Second pipeline; 3. Circumferential weld; 4. Reducing sleeve; 5. First cavity; 6. Second cavity; 7. Third cavity; 8. Die body; 9. Blank steel pipe; 10. Fourth cavity; 11. Fifth cavity; 12. Sixth cavity; 13. Smooth transition structure; 14. Pressure head. DETAILED DESCRIPTION

[0046] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0047] like Figure 1 As shown, an embodiment of the present invention provides a reducing sleeve for repairing a pipeline girth weld, comprising: two sleeve assemblies for interlocking at a defective position of a girth weld 3 between a first pipeline 1 and a second pipeline 2, the two sleeve assemblies being relatively buckled and fixed to form a reducing sleeve 4, the outer diameter of the first pipeline 1 being greater than the outer diameter of the second pipeline 2, a girth weld 3 being arranged between the first pipeline 1 and the second pipeline 2, one end of the reducing sleeve 4 being provided with a first cavity 5 adapted to the outer wall of the first pipeline 1, the other end of the reducing sleeve 4 being provided with a second cavity 6 adapted to the second pipeline 2, the first cavity 5 and the second cavity 6 both having a preset length, and a third cavity 7 for covering the girth weld 3 being arranged in the middle of the reducing sleeve 4.

[0048] The beneficial effects of the technical solution of the present invention are: the designed sleeve cavity is relatively large, which can cover the excess height requirements of different welding joints (girth welds), the two ends of the sleeve and the fitting area of ​​the steel pipe have a certain length, and the inner and outer diameters can be cut according to the actual size of the steel pipe to be repaired, which is convenient for actual assembly and application. It can meet the needs of repairing girth weld defects in pipelines with large wall thickness differences, and the greater the wall thickness difference, the more significant the technical advantage. It solves the problem that it is difficult to directly repair and reinforce girth welds in the prior art. The sleeve is used to be sleeved on the outside of the girth weld, which can meet the in-service repair and reinforcement of girth weld defects between the main pipes of pipelines with unequal wall thicknesses and the butt steel pipes without stopping the oil and gas transmission medium in the pipeline. The improved reducer plus straight pipe section comprehensive structure method not only overcomes the problem of not being able to directly perform welding repairs, but also uses this structure to achieve reinforcement of weak areas of the pipeline structure, and can achieve non-stop welding repair of girth weld defects between the main pipe and the butt steel pipe in the in-service pipeline.

[0049] like Figures 2 to 6 As shown, in addition, the present invention also provides a mold for making a reducing sleeve for repairing a pipeline girth weld as described above, comprising: a mold body 8, wherein both ends of the mold body 8 are respectively provided with a fourth cavity 10 adapted to the outer wall of a blank steel pipe 9 for forming a reducing sleeve 4, the inner diameter of the blank steel pipe 9 is the same as the inner diameter of the third cavity 7, one end of the mold body 8 is provided with a fifth cavity 11 for making a reducing sleeve 4 adapted to the outer wall of the first pipeline 1, and the other end of the mold body 8 is provided with a sixth cavity 12 for making a reducing sleeve 4 adapted to the outer wall of the second pipeline 2, the fifth cavity 11 is connected to the fourth cavity 10 located at one end of the mold body 8, and the sixth cavity 12 is connected to the fourth cavity 10 located at the other end of the mold body 8, and the fifth cavity 11 and the sixth cavity 12 both have a preset length.

[0050] The beneficial effects of the technical solution of the present invention are as follows: two parallel cavities are respectively set in the center, with diameters of D1 (preset length) and D2 (preset length) respectively, and have a certain length, which is used to control the outer diameter size of the two ends of the sleeve and has a certain processing margin. The sixth cavity is used to control the outer diameter of the side with a smaller outer diameter of the sleeve, and the fifth cavity is used to control the outer diameter of the side with a larger outer diameter of the sleeve. The inner diameter size of the entrances at both ends is consistent, and both are adapted to the outer diameter size of the blank steel pipe, which is convenient for the steel pipe to enter and exit during the compression molding process. It can meet the needs of repairing defects in girth welds of pipelines with large wall thickness differences, and the greater the wall thickness difference, the more significant the technical advantage. The large and small heads of the sleeve can be processed at both ends of the mold, saving mold costs. The sleeve cavity made by the mold is larger and can cover the requirements of different welding joint excess heights. The two ends of the sleeve have a certain length in the fitting area with the steel pipe. The inner and outer diameters can be cut according to the actual size of the steel pipe to be repaired, which is convenient for actual assembly applications.

[0051] Among them, the inner diameters of the entrance ports (fourth cavity) at both ends of the mold are consistent, both of which are the outer diameter D of the blank steel pipe.

[0052] Furthermore, there are smooth transition structures 13 between the fifth cavity 11 and the fourth cavity 10 located at one end of the mold body 8 , and between the sixth cavity 12 and the fourth cavity 10 located at the other end of the mold body 8 .

[0053] The beneficial effects of adopting the above further technical solution are: setting the curve for smooth transition, facilitating metal rheology during hot working, and preventing arbitrary deformation of the sleeve.

[0054] The curvature transition (smooth transition structure) of the mold can be set to an arc, a parabola or others.

[0055] Furthermore, the inner diameter of the fifth cavity 11 is the sum of the outer diameter of the first pipe 1 and the wall thickness of the blank steel pipe 9 , and the inner diameter of the sixth cavity 12 is the sum of the outer diameter of the second pipe 2 and the wall thickness of the blank steel pipe 9 .

[0056] The beneficial effect of adopting the above further technical solution is that it is easy to make a sleeve that is compatible with the first pipe and the second pipe through a mold.

[0057] Regardless of internal pressure or axial tensile stress, the actual stress acting on the sleeve (reducing diameter sleeve) is very small, so the sleeve only needs to basically meet the sealing and pressure-bearing effects. By analyzing and considering the difficulty of molding during the forming process, a reducing sleeve for repairing pipe girth welds is designed, which can be a B-type sleeve structure solution for repairing girth weld defects in pipes with large wall thickness differences.

[0058] like Figure 7As shown, in addition, the present invention also provides a method for manufacturing a reducing sleeve for repairing a pipeline girth weld as described above. Based on the pressure head and the mold as described above, the manufacturing method includes:

[0059] S1, pressing one end of the blank steel pipe 9 into the fifth cavity 11 of the mold by the pressing head 14;

[0060] S2. Invert the mold and the blank steel pipe, and press the other end of the blank steel pipe into the sixth cavity of the mold by the pressing head 14.

[0061] The beneficial effects of the technical solution of the present invention are as follows: adopting the large head die pressing method of the different diameter sleeve, placing the large end of the mold upward, pressing the blank steel pipe into the mold with the pressure head, controlling the pressing amount, and pressing out the large head (i.e., the end with the larger outer diameter of the sleeve) of the different diameter sleeve. Then adopting the small head die pressing method of the different diameter sleeve, placing the small end of the mold upward, pressing the blank steel pipe into the mold with the pressure head, controlling the pressing amount, and pressing out the small head (i.e., the end with the smaller outer diameter of the sleeve) of the different diameter sleeve.

[0062] Furthermore, before step S1, the following steps are included:

[0063] measuring the outer diameter of the first pipe, the outer diameter of the second pipe, and the height of the girth weld;

[0064] Select a blank steel pipe with an inner diameter greater than the height of the girth weld and measure the wall thickness of the blank steel pipe;

[0065] The mold is selected according to the outer diameter of the first pipe, the outer diameter of the second pipe and the wall thickness of the blank steel pipe.

[0066] The beneficial effect of adopting the above further technical solution is that it is easy to manufacture the sleeve that is compatible with the first pipe and the second pipe, thereby improving the accuracy.

[0067] Further, step S1 includes:

[0068] S11, heating the blank steel pipe to above the austenite temperature;

[0069] S12, pressing one end of the blank steel pipe into the fifth cavity of the mold by a pressing head;

[0070] Step S2 includes:

[0071] S21, heating the blank steel pipe to above the austenite temperature;

[0072] S22, inverting the mold and the blank steel pipe, and pressing the other end of the blank steel pipe into the sixth cavity of the pressing mold by the pressing head.

[0073] The beneficial effect of adopting the above further technical solution is: heating the blank steel pipe to above the austenite temperature, improving the plasticity of the steel pipe, facilitating the pressure forming of the sleeve, and facilitating processing.

[0074] Furthermore, after step S2, the process includes: performing tempering treatment on the rough steel pipe.

[0075] The beneficial effect of adopting the above further technical solution is: eliminating the internal stress of the sleeve.

[0076] like Figure 8 As shown, again, the present invention also provides a method for using the reducing sleeve for repairing a pipeline girth weld as described above, comprising:

[0077] S1, cutting the different diameter sleeve into two sleeve assemblies along the horizontal axis;

[0078] S2, wrapping two sleeve assemblies on the pipe to be repaired;

[0079] S3. Weld the longitudinal weld and the circumferential weld separately to repair the pipeline defects.

[0080] The beneficial effect of the technical solution of the present invention is: the different-diameter sleeve is cut into two halves along the horizontal axis, wrapped on the pipe to be repaired, and the longitudinal weld and the circumferential weld are welded respectively, so that the pipe defects can be repaired. Among them, the sleeve cavity is relatively large, which can meet the requirements of different welding joint excess heights. In addition, the two ends of the sleeve have a certain length of the fitting area with the steel pipe, and the inner and outer diameters can be cut according to the actual size of the steel pipe to be repaired, which is convenient for actual assembly and application.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A reducing sleeve for repairing pipeline girth welds, characterized in that: include: Two sleeve assemblies are used to be interlocked at the defective position of the girth weld between a first pipe and a second pipe, the two sleeve assemblies are relatively fastened and fixed to form a reducing sleeve, the outer diameter of the first pipe is larger than the outer diameter of the second pipe, a girth weld is provided between the first pipe and the second pipe, one end of the reducing sleeve is provided with a first cavity adapted to the outer wall of the first pipe, the other end of the reducing sleeve is provided with a second cavity adapted to the second pipe, the first cavity and the second cavity both have a preset length, and the middle part of the reducing sleeve is provided with a third cavity for covering the girth weld.

2. A mold for making a reducing sleeve for repairing a pipe girth weld as claimed in claim 1, characterized in that: include: A mold body, wherein both ends of the mold body are respectively provided with fourth cavities adapted to the outer wall of a blank steel pipe for forming a reducing sleeve, the inner diameter of the blank steel pipe is the same as the inner diameter of the third cavity, one end of the mold body is provided with a fifth cavity for making a reducing sleeve adapted to the outer wall of the first pipe, and the other end of the mold body is provided with a sixth cavity for making a reducing sleeve adapted to the outer wall of the second pipe, the fifth cavity is communicated with the fourth cavity located at one end of the mold body, and the sixth cavity is communicated with the fourth cavity located at the other end of the mold body, and the fifth cavity and the sixth cavity both have preset lengths.

3. A mold for making a reducing sleeve for repairing a pipeline girth weld according to claim 2, characterized in that: There are smooth transition structures between the fifth cavity and the fourth cavity located at one end of the mold body, and between the sixth cavity and the fourth cavity located at the other end of the mold body.

4. A mold for making a reducing sleeve for repairing a pipeline girth weld according to claim 2, characterized in that: The inner diameter value of the fifth cavity is the sum of the outer diameter of the first pipe and the wall thickness of the blank steel pipe, and the inner diameter value of the sixth cavity is the sum of the outer diameter of the second pipe and the wall thickness of the blank steel pipe.

5. A method for manufacturing a reducing sleeve for repairing a pipeline girth weld as claimed in claim 1, characterized in that: Based on the pressure head and the mold as claimed in claim 2, the manufacturing method includes: S1, press one end of the blank steel pipe into the fifth cavity of the mold through a pressing head; S2. Invert the mold and the blank steel pipe, and press the other end of the blank steel pipe into the sixth cavity of the mold by using a pressing head.

6. A method for manufacturing a reducing sleeve for repairing a pipeline girth weld according to claim 5, characterized in that: Step S1 includes: measuring the outer diameter of the first pipe, the outer diameter of the second pipe, and the height of the girth weld; Select a blank steel pipe with an inner diameter greater than the height of the girth weld and measure the wall thickness of the blank steel pipe; The mold is selected according to the outer diameter of the first pipe, the outer diameter of the second pipe and the wall thickness of the blank steel pipe.

7. The method for manufacturing a reducing sleeve for repairing a pipeline girth weld according to claim 5, characterized in that: Step S1 includes: S11, heating the blank steel pipe to above the austenite temperature; S12, pressing one end of the blank steel pipe into the fifth cavity of the mold by a pressing head; Step S2 includes: S21, heating the blank steel pipe to above the austenite temperature; S22, inverting the mold and the blank steel pipe, and pressing the other end of the blank steel pipe into the sixth cavity of the pressing mold by the pressing head.

8. The method for manufacturing a reducing sleeve for repairing a pipeline girth weld according to claim 5, characterized in that: The process after step S2 includes: performing tempering treatment on the rough steel pipe.

9. A method for using the reducing sleeve for repairing a pipeline girth weld according to claim 1, characterized in that: include: S1, cutting the different diameter sleeve into two sleeve assemblies along the horizontal axis; S2, wrapping two sleeve assemblies on the pipe to be repaired; S3. Weld the longitudinal weld and the circumferential weld separately to repair the pipeline defects.

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