Conical stress joint of composite metal material structure of flange connecting vertical pipe

Abstract

The utility model discloses a conical stress joint of a composite metal material structure of a flange connection stand pipe, which comprises a main body pipe with a constant inner diameter, one end of the main body pipe is fixedly provided with an upper connecting flange used for being connected with a marine oil and gas resource exploitation platform, and the other end of the main body pipe is fixedly provided with a lower connecting flange used for being connected with a marine oil and gas exploitation stand pipe. Titanium alloy outer reinforcing layers with the thicknesses gradually decreased are attached to the outer surface of the main body pipe in a metallurgical mode. The main body pipe is connected with the marine oil and gas production vertical pipe through the lower connecting flange, and compared with a traditional mode that the marine oil and gas production vertical pipe is connected with a conical stress connector through welding, the mode is simpler and more convenient; the titanium alloy is attached to the outer surface of the main body pipe in a metallurgical mode, the main body pipe is made of a composite material instead of a single material, the titanium alloy has the characteristics of good strength, corrosion resistance and high temperature resistance, the strength of the main body pipe can be improved, and the main body pipe is not prone to breakage while bearing constant vertical pipe tension and can adapt to high temperature and corrosion of the marine environment.

Description

Technical Field

[0001] The utility model relates to the technical field of marine oil and gas resource exploitation equipment, in particular to a tapered stress joint of a composite material structure of a flange-connected riser. Background Art

[0002] In the marine underwater oil and gas resource exploration and production system, the riser system is the connection channel between the water platform and the underwater equipment, the "throat" of the medium transmission between the platform and the seabed, and the key component of the underwater production system. The steel catenary riser (SCR) is an important riser form for deepwater oil and gas development. The stress joint, as a key device of the SCR system, realizes the connection between the riser and the platform. It not only needs to withstand hundreds of tons of constant riser tension, but also needs to withstand the long-term swing of the riser under environmental loads. The design and performance of the SCR stress joint directly affect the safety and reliability of the entire riser system. The existing stress joint is made of steel. Because steel is heavy and has poor corrosion resistance, it has obvious nonlinear characteristics under marine environmental loads and marine corrosion, and the fatigue problem is prominent, and the application effect and safety are poor. At present, there are single-material stress joints such as F56 forgings or Gr-23 or Gr-29. The stress joints of single-material F56 forgings have poor bending resistance, are prone to fatigue fracture failure, and have poor corrosion resistance. The production and manufacturing process of single-material Gr-23 or Gr-29 stress joints is single, resulting in high prices. Utility Model Content

[0003] The utility model aims to provide a conical stress joint of composite metal material structure for flange-connected riser, which has high strength, corrosion resistance and is easy to install.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A conical stress joint of a composite metal material structure for a flange-connected riser, comprising a main pipe with a constant inner diameter, one end of the main pipe being fixed with an upper connecting flange for connecting to an offshore oil and gas resource exploitation platform, and the other end being fixed with a lower connecting flange for connecting to an offshore oil and gas production riser, and an outer surface of the main pipe being metallurgically attached with a titanium alloy outer reinforcement layer whose thickness decreases from top to bottom.

[0006] Furthermore, the cross-section line of the outer reinforcement layer is parabolic.

[0007] Furthermore, the material of the upper connecting flange and the lower connecting flange is F56 forging material of ASTM A694, the material of the main pipe is F56 forging material of ASTM A694 or API 5LX56 pipe, and the titanium alloy is ASTM B265Gr-23 or Gr-29.

[0008] Furthermore, the material of the upper connecting flange and the lower connecting flange is titanium material of ASTM B265 Gr-23 type, the material of the main pipe is titanium material of ASTM B265 Gr-23 type, and the titanium alloy is ASTM B265 Gr-29 type.

[0009] Furthermore, the upper connecting flange and the lower connecting flange are welded and fixed at both ends of the main pipe.

[0010] Furthermore, the upper connecting flange, the main pipe and the lower connecting flange are an integrally formed structure.

[0011] Compared with the prior art, the utility model has the following beneficial effects:

[0012] 1. The utility model joint includes an upper connecting flange and a lower connecting flange. The main pipe is connected to the offshore oil and gas resource exploitation platform through the upper connecting flange, and is connected to the offshore oil and gas riser through the lower connecting flange. Compared with the traditional method of connecting the offshore oil and gas riser with the tapered stress joint by welding, this method is simpler and more convenient. Titanium alloy is metallurgically attached to the outer surface of the main pipe by 3D powder metallurgy forming technology, so that the main pipe is changed from a single material to a composite material. Titanium alloy has good strength, corrosion resistance and high temperature resistance, which can improve the strength of the main pipe, so that it is not easy to break while bearing constant riser tension, and can adapt to the high temperature and corrosion of the marine environment. The weight of titanium alloy is lighter than that of steel, which can greatly reduce the dead weight of the tapered stress.

[0013] 2. The thickness of the titanium alloy on the outer surface of the main tube of the utility model decreases successively and forms a cone. The specific size of the cone structure can be designed and calculated according to the specific working load. The upper end is connected to the offshore oil and gas resource exploitation platform. After being subjected to environmental loads, it is easy to swing, the stress at the connection increases, and it is easy to fail. The thickness of the reinforcement layer at the upper part of the cone is large, which can increase its performance against stress, help to evenly distribute stress at different depths, reduce stress concentration, and thus improve the fatigue life and overall stability of the joint.

[0014] 3. The utility model is manufactured through 3D powder metallurgy forming technology, which can effectively reduce the manufacturing cost caused by material waste compared with the traditional forging process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0016] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present utility model;

[0017] 1-upper connecting flange; 2-main pipe; 3-lower connecting flange; 4-outer reinforcement layer; 5-upper connecting flange butt weld, 6-lower connecting flange butt weld. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0019] like Figure 1 As shown, the utility model includes an upper connection flange 1, a main pipe 2, a lower connection flange 3, an outer reinforcement layer 4, an upper connection flange butt weld 5 and a lower connection flange butt weld 6. The upper connection flange 1 is fixedly connected to the main pipe 2 by welding, and the connection is the upper connection flange butt weld 5. The welding method of the upper connection flange butt weld 5 is argon arc welding; the lower connection flange 3 is fixedly connected to the other end of the main pipe 2 by welding, and the connection is the lower connection flange butt weld 6. The welding method of the lower connection flange butt weld 6 is argon arc welding; the upper connection flange 1 is connected to the offshore oil and gas resource mining platform, and the lower connection flange 3 is connected to the offshore oil and gas production riser. The outer reinforcement layer 4 is made of titanium alloy material and attached to the outer surface of the main pipe 2 through 3D powder metallurgy forming technology. The outer and inner diameters of the main pipe 2 are constant. The thickness of the outer reinforcement layer 4 decreases from top to bottom. In its cross-sectional view, the contour line of the outer reinforcement layer 4 is parabolic. The 3D powder metallurgy forming technology adopts plasma spray welding or laser cladding welding. On the outer wall of the main pipe 2 with a constant inner diameter. The upper connecting flange 1 and the lower connecting flange 3 are made of ASTM A694 F56 forging material, the main pipe 2 is made of ASTM A694 F56 forging material or API 5LX56 pipe material, and the outer reinforcement layer 4 is made of ASTM B265 Gr-23 or Gr-29 titanium material. The high-strength, corrosion-resistant titanium alloy is attached to the surface of the steel material to form a composite material to increase the strength and service life of the main pipe. If the upper connecting flange 1 and the lower connecting flange 3 are made of ASTM B 265Gr-23 titanium material, the main pipe 2 is made of ASTM B 265Gr-23 titanium material, and the outer reinforcement layer 4 is made of ASTM B 265Gr-29 titanium material. By attaching a higher grade of titanium material to the surface of the lower grade titanium main pipe 2, the overall strength and elastic modulus of the main pipe 2 are improved, so that it has better corrosion resistance and high temperature resistance.

[0020] like Figure 2 As shown, another embodiment of the present invention is that the upper connecting flange 1, the main pipe 2 and the lower connecting flange 3 are formed into one piece at one time through a forging process.

[0021] The manufacturing method of the utility model comprises the following steps:

[0022] Step 1: produce the upper connecting flange 1 and the lower connecting flange 3 by a forging manufacturing process, and produce the main pipe 2 by a forging manufacturing process or a pipe rolling manufacturing process;

[0023] Step 2: The upper connecting flange 1 and the lower connecting flange 3 are welded together with the main pipe 2 by argon arc welding; the upper connecting flange 1, the main pipe 2 and the lower connecting flange 3 can also be formed at one time by a forging manufacturing process;

[0024] Step 3: metallurgically forming an outer reinforcement layer 4 on the outer surface of the main tube 2 by 3D powder metallurgy forming technology, and the outer reinforcement layer 4 needs to reserve a margin for subsequent mechanical finishing;

[0025] Step 4: placing the tapered stress joint that has been metallurgically formed in step 3 in a heat treatment furnace for post-weld heat treatment to obtain a semi-finished product;

[0026] Step 5: Mechanically finish the outer dimensions of the semi-finished product described in step 4.

[0027] The utility model forms a composite material by metallurgically forming a high-strength outer reinforcement layer 4 on the surface of a low-strength main pipe 2. Compared with traditional stress joints made of a single material, the utility model adopts low-cost titanium alloy, which can reduce production costs on the one hand, and on the other hand, in a deep-sea environment, the conical stress joint at the top of the steel catenary riser will be subject to complex dynamic loads, which will have a significant impact on the fatigue life of the joint. Titanium alloy has excellent strength, corrosion resistance and high temperature resistance, and can effectively extend the life of the conical stress joint.

Claims

1. A tapered stress joint of composite metal material structure for flange connection riser, characterized in that: The invention comprises a main body pipe (2) with a constant inner diameter, wherein an upper connecting flange (1) for connecting to an offshore oil and gas resource exploitation platform is fixed at one end of the main body pipe (2), and a lower connecting flange (3) for connecting to an offshore oil and gas production riser is fixed at the other end, and a titanium alloy outer reinforcement layer (4) with a thickness decreasing from top to bottom is metallurgically attached to the outer surface of the main body pipe (2).

2. The tapered stress joint of composite metal material structure for flange connection riser according to claim 1, characterized in that: The cross-section line of the outer reinforcement layer (4) is parabolic.

3. The tapered stress joint of composite metal material structure for flange connection riser according to claim 1 or 2, characterized in that: The upper connecting flange (1) and the lower connecting flange (3) are made of F56 forging material of ASTM A694, the main pipe (2) is made of F56 forging material of ASTM A694 or API 5L X56 pipe, and the titanium alloy is ASTM B265 Gr-23 type or Gr-29 type.

4. The tapered stress joint of composite metal material structure for flange connection riser according to claim 1 or 2, characterized in that: The material of the upper connecting flange (1) and the lower connecting flange (3) is titanium material of ASTM B265 Gr-23 type, the material of the main pipe (2) is titanium material of ASTM B265 Gr-23 type, and the titanium alloy is ASTM B265Gr-29 type.

5. The tapered stress joint of composite metal material structure for flange connection riser according to claim 1, characterized in that: The upper connecting flange (1) and the lower connecting flange (3) are welded and fixed at both ends of the main pipe (2).

6. The tapered stress joint of composite metal material structure for flange connection riser according to claim 1, characterized in that: The upper connecting flange (1), the main body pipe (2) and the lower connecting flange (3) are an integrally formed structure.

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