Large-diameter steel pipe end sizing and wall uniformizing device

Abstract

The utility model discloses a large-diameter steel pipe end sizing and wall uniformizing device which comprises a first hydraulic oil cylinder, the output end of the first hydraulic oil cylinder is fixedly connected with a first connecting rod, the right side of the first connecting rod is fixedly connected with a baffle, and the right side of the baffle is fixedly connected with a steel pipe body. And rotating rollers are arranged at the top and the bottom of the outer side of the back face of the steel pipe body, a grinding module is arranged at the top of the steel pipe body, and a medium-frequency induction coil is wound on the surface of the steel pipe body. According to the sizing and wall uniformizing device, the phenomenon of low efficiency of traditional sizing and wall uniformizing is changed, the pipe end of the steel pipe body is rolled after being heated, required rolling force is small, the requirement for a hydraulic power system is lowered, the pipe end of the steel pipe body is heated through the medium-frequency induction coil, the temperature rising speed is high, the temperature is convenient to control, and the grinding module is arranged, so that the production efficiency is improved. The required part of the outer surface of the steel pipe body can be ground, and the adverse effect of the scale on the surface of the pipe end on the sizing uniform wall is eliminated.

Description

Technical Field

[0001] This utility model relates to the field of metal forming and processing technology, specifically to a device for sizing and equalizing the wall thickness at the end of a large-diameter steel pipe. Background Technology

[0002] Welded steel pipes are commonly used in long-distance gathering and transportation pipelines. Compared to seamless steel pipes, welded steel pipes have advantages such as uniform wall thickness, high dimensional accuracy of pipe ends, and ease of butt joint connection. However, in the field of transporting acidic media, such as high-sulfur natural gas, acidic media easily form hydrogen-induced cracking (HIC) and hydrogen sulfide stress corrosion (SSC) at weld defects. Especially with the large-scale promotion and application of hydrogen energy, green hydrogen produced by solar and wind energy in Northwest China needs to be transported to coastal industrial areas, making the construction of long-distance hydrogen pipeline networks imminent. Because welded steel pipes are prone to processing defects and the accumulation of non-metallic inclusions in the welds, the welds are more susceptible to hydrogen embrittlement under high-pressure hydrogen. Therefore, long-distance pipelines for hydrogen and acidic service environments are particularly vulnerable.

[0003] According to a patent published on the China Patent Network, the patent title is: "Manufacturing Method of Large-Diameter High-Strength Seamless Steel Pipe for Gathering and Transportation in High Hydrogen Sulfide Environments," patent application number: 201310422486.3. This method includes steps such as reasonable steel grade proportioning, steelmaking, PQF continuous rolling, 720EM skew rolling and expansion, quenching and tempering treatment, and processing technology. The effect of this method is to utilize the contribution of residual elements to performance, rationally adjust composition control, and obtain a gathering and transportation pipe suitable for high hydrogen sulfide environments through skew rolling and expansion technology and unique heat treatment technology. It not only meets the strength requirements under high operating pressures for gathering and transportation but also meets the requirements for resistance to hydrogen sulfide corrosion in acidic environments. This steel pipe has good physical and chemical properties, high dimensional accuracy, and is easy to manufacture. This technology is applicable to pipelines and is beneficial for pipeline safety, making it widely suitable for use in acidic oil and gas fields with high hydrogen sulfide content. However, after the seamless steel pipe is cold-sized by four sets of cold rolling rolls, the outer diameter accuracy is ±0.75%D and the wall thickness accuracy is ±12.5%t. The misalignment between steel pipes is relatively large, making welding difficult. In the above-mentioned technologies, multi-stand sizing mills are usually used to sizing hot-rolled steel pipes, or multi-roll cold sizing mills are used for cold rolling sizing. Both types of units use complex and large equipment and control systems, resulting in high equipment investment and energy consumption. Furthermore, the wall thickness cannot be made uniform during the sizing process, and the dimensional control accuracy of the pipe ends is difficult to meet the requirements of GB / T9711-2017 "Oil and Gas Industry - Steel Pipes for Pipeline Transportation Systems".

[0004] Therefore, it is necessary to redesign and modify the sizing and wall-leveling device to effectively prevent its slow sizing and wall-leveling efficiency. Utility Model Content

[0005] To address the problems mentioned in the background art, the purpose of this utility model is to provide a large-diameter steel pipe end sizing and wall equalization device, which has the advantage of rapidly improving the dimensional accuracy of the steel pipe end, including diameter, wall thickness and out-of-roundness, and solves the problem of slow efficiency in sizing and wall equalization of steel pipe ends.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a large-diameter steel pipe end sizing and wall thickness equalization device, comprising a hydraulic cylinder, a first connecting rod fixedly connected to the output end of the hydraulic cylinder, a baffle fixedly connected to the right side of the first connecting rod, a steel pipe body fixedly connected to the right side of the baffle, rotating rollers provided at the top and bottom of the outer side of the back of the steel pipe body, a grinding module provided at the top of the steel pipe body, a medium-frequency induction coil wound on the surface of the steel pipe body, an active roller provided at the right side of the top of the steel pipe body, a driven roller provided at the right side of the bottom of the steel pipe body, a mandrel provided at the right side of the steel pipe body, a conveying roller provided on the back of the mandrel, a coupling provided at the right side of the mandrel, a second connecting rod provided at the right side of the coupling, a second hydraulic cylinder provided at the right side of the second connecting rod, the output end of the second hydraulic cylinder being fixedly connected to the second connecting rod, and a steel pipe limiting component provided on the right side of the surface of the steel pipe body.

[0007] In a preferred embodiment of this invention, the core mold includes a tapered section, a sizing section, and a connecting plate. The tapered section is located on the left side of the outer side of the core mold, the sizing section is located on the outer side of the core mold, and the connecting plate is located on the right side of the core mold.

[0008] As a preferred embodiment of this invention, the cone angle α of the tapered section is 8~12°, the connection between the tapered section and the sizing section is smoothly transitioned, and the outer diameter deviation of the sizing section is less than ±0.1mm.

[0009] As a preferred embodiment of this invention, the diameter of the small end of the tapered section is 30-50 mm smaller than the inner diameter of the inner tube.

[0010] As a preferred embodiment of this utility model, the outer diameter of the sizing section is equal to the diameter of the steel pipe body without heating, and the length L of the sizing section is: L=L1+W1+(50~80)mm, where L1 is the length of the steel pipe body that needs to be sizing and equalizing the wall thickness, W1 is the width of the driving roller, and the width W2 of the driven roller is equal to the length L of the sizing section.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0012] 1. This utility model of sizing and wall thickness equalization device changes the slow efficiency of traditional sizing and wall thickness equalization. By heating the steel pipe body before rolling the pipe end, the required rolling force is small, reducing the requirements of the hydraulic power system. The steel pipe body and pipe end are heated by a medium frequency induction coil, resulting in rapid heating and easy temperature control. It is equipped with a grinding module, which can grind the required parts of the outer surface of the steel pipe body to eliminate the adverse effects of oxide scale on the pipe end surface on sizing and wall thickness equalization. The mandrel is easy to replace, and different sizes of mandrels can be used to perform sizing and wall thickness equalization operations on steel pipe bodies of different specifications. At the same time, it plays a role in sizing and equalizing the wall thickness of the steel pipe body and pipe end, thereby improving production efficiency.

[0013] 2. By including a tapered section, a sizing section, and a connecting plate in the core mold, this utility model can improve the quality of the core mold and also increase the convenience of insertion and removal.

[0014] 3. By setting the cone angle α of the tapered section to 8~12°, this utility model enables a more convenient connection between the tapered section and the sizing section, avoiding connection difficulties.

[0015] 4. By setting the small end diameter of the tapered section to be 30-50mm smaller than the inner diameter of the inner tube, this utility model enables the core mold to move more stably and increases the convenience of pushing in the core mold.

[0016] 5. By setting the outer diameter of the sizing section to be equal to the diameter of the steel pipe body before heating, this utility model can achieve the effect of sizing the steel pipe body and increase the processing stability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the core mold of this utility model.

[0019] In the diagram: 1. Hydraulic cylinder one; 2. First connecting rod; 3. Baffle; 4. Steel pipe body; 5. Rotating roller; 6. Grinding module; 7. Medium frequency induction coil; 8. Driving roller; 9. Driven roller; 10. Mandrel; 101. Conical section; 102. Sizing section; 103. Connecting plate; 11. Conveying roller; 12. Coupling; 13. Second connecting rod; 14. Hydraulic cylinder two; 15. Steel pipe limiting assembly. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] like Figures 1 to 2 As shown, the present invention provides a large-diameter steel pipe end sizing and wall equalization device, including a hydraulic cylinder 1, a first connecting rod 2 fixedly connected to the output end of the hydraulic cylinder 1, a baffle 3 fixedly connected to the right side of the first connecting rod 2, a steel pipe body 4 fixedly connected to the right side of the baffle 3, rotating rollers 5 provided at the top and bottom of the outer side of the back of the steel pipe body 4, a grinding module 6 provided at the top of the steel pipe body 4, a medium frequency induction coil 7 wound on the surface of the steel pipe body 4, an active roller 8 provided at the right side of the top of the steel pipe body 4, a driven roller 9 provided at the right side of the bottom of the steel pipe body 4, a mandrel 10 provided at the right side of the steel pipe body 4, a conveying roller 11 provided on the back of the mandrel 10, a coupling 12 provided at the right side of the mandrel 10, a second connecting rod 13 provided at the right side of the coupling 12, a hydraulic cylinder 14 provided at the right side of the second connecting rod 13, the output end of the hydraulic cylinder 14 fixedly connected to the second connecting rod 13, and a steel pipe limiting component 15 provided on the right side of the surface of the steel pipe body 4.

[0022] refer to Figure 1 and Figure 2 The core mold 10 includes a tapered section 101, a sizing section 102, and a connecting plate 103. The tapered section 101 is located on the left side of the outer side of the core mold 10, the sizing section 102 is located on the outer side of the core mold 10, and the connecting plate 103 is located on the right side of the core mold 10.

[0023] As a technical optimization of this utility model, by including a tapered section 101, a sizing section 102 and a connecting plate 103 in the core mold 10, the quality of the core mold 10 can be improved, and the convenience of insertion and removal can also be increased.

[0024] refer to Figure 1 and Figure 2 The cone angle α of the tapered section 101 is 8~12°, the connection between the tapered section 101 and the sizing section 102 is smooth, and the outer diameter deviation of the sizing section 102 is less than ±0.1mm.

[0025] As a technical optimization of this utility model, by setting the cone angle α of the tapered section 101 to be 8~12°, the tapered section 101 and the sizing section 102 can be connected more conveniently, avoiding the phenomenon of connection difficulties.

[0026] refer to Figure 1 and Figure 2 The small end diameter of the tapered section 101 is 30-50 mm smaller than the inner diameter of the inner tube.

[0027] As a technical optimization of this utility model, by setting the small end diameter of the tapered section 101 to be 30-50mm smaller than the inner diameter of the inner tube, the core mold 10 can move more stably, and the convenience of pushing the core mold 10 in is increased.

[0028] refer to Figure 1 and Figure 2 The outer diameter of the sizing section 102 is equal to the diameter of the steel pipe body 4 when the pipe end is not heated. The length L of the sizing section 102 is: L = L1 + W1 + (50~80) mm, where L1 is the length of the steel pipe body 4 pipe end that needs to be sizing and equalized, W1 is the width of the driving roller 8, and the width W2 of the driven roller 9 is equal to the length L of the sizing section 102.

[0029] As a technical optimization of this utility model, by setting the outer diameter of the sizing section 102 to be equal to the diameter of the steel pipe body 4 when the pipe end is not heated, the steel pipe body 4 can be sizing, thereby increasing the processing stability.

[0030] The working principle and usage process of this utility model are as follows: First, the sizing and wall-leveling device is processed in three steps:

[0031] First, pipe end grinding: Hydraulic cylinder 1 pushes the steel pipe body 4 to move axially on the rotating roller 5 through the first connecting rod 2 and the baffle 3. When the pipe end of the steel pipe body 4 that needs to be sized and wall-evened moves to the position of the grinding module 6, the rotating roller 5 drives the steel pipe body 4 to rotate. The grinding module 6 first grinds the pipe end that needs to be sized and wall-evened to eliminate the oxide scale and possible defects on the outer surface of the pipe end of the steel pipe body 4, so as to avoid the oxide scale being crushed into the steel pipe body 4 and forming defects during the subsequent sizing and wall-evening process.

[0032] Second, pipe end heating: After the grinding is completed, the hydraulic cylinder 1 pushes the steel pipe to move axially on the steel pipe body 4 through the first connecting rod 2 and the baffle 3. When the pipe end of the steel pipe body 4 that needs to be sized and uniformly walled moves to the position of the medium frequency induction coil 7, the medium frequency induction heating coil 7 is then started to heat the pipe end that needs to be sized and uniformly walled. After heating to the specified process temperature, the medium frequency induction coil 7 stops heating.

[0033] Third, pipe end sizing and wall thickness equalization: After the pipe end of the steel pipe body 4 that requires sizing and wall thickness equalization reaches the specified heating temperature, the intermediate frequency induction coil 7 stops heating. Hydraulic cylinder 1 pushes the steel pipe body 4 axially on the rotating roller 5 through the first connecting rod 2 and the baffle 3. The pipe end of the steel pipe body 4 that requires sizing and wall thickness equalization moves to contact the steel pipe limiting component 15. High-temperature resistant lubricant is applied to the surface of the sizing section 102 of the mandrel 10. Hydraulic cylinder 2 14 drives the mandrel 10 axially on the conveying roller 11 through the second connecting rod 13 and the coupling 12, pushing the mandrel 10 into the steel pipe body 4. After the sizing section 102 is flush with the pipe end, the connection between the coupling 12 and the connecting plate 103 is released. At this time, the coupling 12 is still in contact with the connecting plate 103, which plays an axial limiting role for the mandrel 10. According to the required diameter and wall thickness of the pipe end of the steel pipe body 4, the radial clearance between the active roller 8 and the sizing section 102 is set, and the start-up is initiated. The active roller 8 rolls the end of the steel pipe body 4 at a set temperature. The speed of its axial movement is set according to the rotation speed of the active roller 8 to ensure that the rolling surface fully covers the entire outer surface of the pipe end that needs to be sized and walled. The active roller 8 can rotate clockwise or counterclockwise and can move forward or backward along the axial direction of the steel pipe body 4. According to the required diameter and wall thickness accuracy of the steel pipe body 4 end, the required number of rolling passes are performed on the steel pipe body 4 end. After the required sizing and wall thickness requirements are met, the coupling 12 is connected to the connecting plate 103. The hydraulic cylinder 14 drives the mandrel 10 to move in the opposite direction through the second connecting rod 13 and the coupling 12, pulling the mandrel 10 out of the steel pipe body 4. In order to facilitate the mandrel 10 to be pulled out of the steel pipe body 4, the end of the steel pipe body 4 can be heated by the medium frequency induction coil 7 to achieve the effect of quickly improving the dimensional accuracy of the steel pipe end, including diameter, wall thickness and out-of-roundness.

[0034] In summary, this large-diameter steel pipe end sizing and wall thickness equalization device overcomes the slow efficiency of traditional sizing and wall thickness equalization methods. By heating the pipe end before rolling, the required rolling force is small, reducing the demands on the hydraulic power system. The pipe end is heated by a medium-frequency induction coil 7, resulting in rapid heating and easy temperature control. The device includes a grinding module 6, which can grind the required areas on the outer surface of the pipe end to eliminate the adverse effects of oxide scale on sizing and wall thickness equalization. The mandrel 10 is easily replaceable, and different sizes of mandrels 10 can be used to perform sizing and wall thickness equalization operations on steel pipes of different specifications. Simultaneously, it sizing and equalizing the wall thickness at the pipe end improves production efficiency.

[0035] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0036] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for sizing and equalizing the wall thickness of large-diameter steel pipe ends, comprising a hydraulic cylinder (1), characterized in that: The output end of the hydraulic cylinder (1) is fixedly connected to a first connecting rod (2). A baffle (3) is fixedly connected to the right side of the first connecting rod (2). A steel pipe body (4) is fixedly connected to the right side of the baffle (3). Rotating rollers (5) are provided at the top and bottom of the outer side of the back of the steel pipe body (4). A grinding module (6) is provided at the top of the steel pipe body (4). A medium-frequency induction coil (7) is wound around the surface of the steel pipe body (4). An active roller (8) is provided on the right side of the top of the steel pipe body (4). The bottom of the steel pipe body (4) A driven roller (9) is provided on the right side of the part, a core mold (10) is provided on the right side of the steel pipe body (4), a conveying roller (11) is provided on the back of the core mold (10), a coupling (12) is provided on the right side of the core mold (10), a second connecting rod (13) is provided on the right side of the coupling (12), a second hydraulic cylinder (14) is provided on the right side of the second connecting rod (13), the output end of the second hydraulic cylinder (14) is fixedly connected to the second connecting rod (13), and a steel pipe limiting assembly (15) is provided on the right side of the surface of the steel pipe body (4).

2. The pipe end sizing and wall thickness equalization device for large-diameter steel pipes according to claim 1, characterized in that: The core mold (10) includes a tapered section (101), a sizing section (102), and a connecting plate (103). The tapered section (101) is located on the left side of the core mold (10), the sizing section (102) is located on the outside of the core mold (10), and the connecting plate (103) is located on the right side of the core mold (10).

3. The pipe end sizing and wall thickness equalization device for large-diameter steel pipes according to claim 2, characterized in that: The cone angle α of the tapered section (101) is 8~12°, the connection between the tapered section (101) and the sizing section (102) is smoothly transitioned, and the outer diameter deviation of the sizing section (102) is less than ±0.1mm.

4. The pipe end sizing and wall thickness equalization device for large-diameter steel pipes according to claim 2, characterized in that: The small end diameter of the tapered section (101) is 30-50 mm smaller than the inner diameter of the inner tube.

5. The pipe end sizing and wall thickness equalization device for large-diameter steel pipes according to claim 2, characterized in that: The outer diameter of the sizing section (102) is equal to the diameter of the pipe end of the steel pipe body (4) when it is not heated. The length L of the sizing section (102) is: L=L1+W1+(50~80)mm, where L1 is the length of the pipe end of the steel pipe body (4) that needs to be sizing and wall-leveling, W1 is the width of the active roller (8), and the width W2 of the driven roller (9) is equal to the length L of the sizing section (102).

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