Conical stress joint of composite material structure for butt welding connection of vertical pipes

Abstract

The utility model discloses a conical stress joint of a composite material structure of a butt welding connection vertical pipe, which comprises a main body pipe and an upper connecting flange which is fixed at the top end of the main body pipe and is used for being connected with an offshore oil and gas resource exploitation platform, the titanium material outer reinforcing layer is attached to the outer surface of the main body pipe in a metallurgical mode, the strength of the main body pipe is enhanced, the main body pipe can bear more loads and is not prone to breakage, the main body pipe can bear corrosion of high-temperature chlorides, sulfides, ammonia and other media during seabed operation, the safety and the service life of marine resource exploitation equipment are guaranteed, and the marine resource exploitation pipe is used for offshore oilfield exploitation equipment.

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 for butt-welding a 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 surface platform and the underwater equipment, the "throat" of the medium transmission between the platform and the seabed, and a 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. While bearing hundreds of tons of constant riser tension, it also bears the long-term swing of the riser under the action of environmental loads. Due to the complex loads and the harsh environment that the stress joint bears, the stress joint is a weak link in the SCR system, and there is a risk of structural failure and leakage. At present, there are stress joints made of single materials such as F56 forgings or Gr-23 or Gr-29. The stress joints made of single material F56 forgings have poor bending resistance, are prone to fatigue fracture failure, and have poor corrosion resistance. The manufacturing process of the Gr-23 or Gr-29 stress joints made of single material F56 forgings is single, resulting in high prices, and the joints can only be connected to the riser through flanges, which are prone to leakage and other problems. Utility Model Content

[0003] The utility model aims to provide a tapered stress joint of a composite material structure for butt-welding a riser, which has high strength, corrosion resistance and long service life.

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

[0005] A tapered stress joint of a composite material structure for butt-welding a riser, comprising a main pipe and an upper connecting flange fixed to the top of the main pipe for connecting to an offshore oil and gas resource exploitation platform, wherein a titanium alloy outer reinforcement layer with successively decreasing thickness is metallurgically attached to the outer surface of the main pipe.

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

[0007] Furthermore, the material of the upper connecting flange is F56 forging material of ASTM A694, the material of the main pipe is F56 forging material of ASTM A694 or API 5L X56 pipe, and the titanium alloy is ASTM B265 Gr-23 or Gr-29.

[0008] Furthermore, the upper connecting flange and the main pipe are an integrally formed structure.

[0009] Furthermore, the upper connecting flange is fixed to the main pipe by welding.

[0010] Compared with the prior art, the utility model has the following beneficial effects:

[0011] 1. The utility model metallurgically attaches an outer reinforcement layer to the outer surface of the main pipe. Since the bending moment borne by the stress joint gradually increases from the lower end to the upper end, the outer reinforcement layer is designed to be a conical structure. The specific size of the conical structure can be designed and calculated according to the specific working load. A layer of titanium alloy is attached to the outer surface of the main pipe through 3D powder metallurgy forming technology. Compared with the traditional stress joint of a single material, the utility model uses titanium as a composite material and is manufactured through 3D powder metallurgy forming technology. On the one hand, it avoids the material waste caused by the traditional forging process and effectively reduces the production cost. On the other hand, titanium has good mechanical properties and corrosion resistance, which can enhance the strength of the main pipe, so that it can withstand more loads and is not easy to break. It can withstand the corrosion of high-temperature chlorides, sulfides, ammonia and other media during seabed operations, ensuring the safety and service life of marine resource exploitation equipment.

[0012] 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0014] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present utility model;

[0015] 1-upper connecting flange; 2-main pipe; 3-outer reinforcement layer; 4-butt weld of upper connecting flange. DETAILED DESCRIPTION

[0016] 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.

[0017] like Figure 1As shown, the utility model includes an upper connection flange 1, a main pipe 2 and an outer reinforcement layer 3. The material of the upper connection flange 1 is F56 forging material of ASTM A694, the material of the main pipe 2 is F56 forging material of ASTM A694 or API 5LX56 pipe, and the material of the outer reinforcement layer 3 is titanium material of ASTM B265 Gr-23 or Gr-29; one end of the main pipe 2 is fixed with the upper connection flange 1 for connecting with the offshore oil and gas resource mining platform, and the other end is connected with the offshore oil and gas production riser by butt welding. The inner diameter of the main pipe 2 is constant, and the outer reinforcement layer 3 is attached to its outer surface. The attachment thickness of the outer reinforcement layer 3 decreases successively, so that the attached main pipe is conical. The outline of the outer reinforcement layer 3 in its cross-sectional view is parabolic. The outer reinforcement layer 3 is metallurgically attached to the outer surface of the main pipe 2 by 3D powder metallurgy forming technology. The 3D powder metallurgy forming technology adopts plasma spray welding or laser cladding welding. The upper connection flange 1 and the main pipe 2 are formed into one piece by a forging process.

[0018] like Figure 2 As shown, in another embodiment of the utility model, the upper connecting flange 1 and the main pipe 2 are fixed by welding, and the fixed connection point is the upper connecting flange butt weld 4, and the welding method is argon arc welding.

[0019] The manufacturing method of the utility model comprises the following steps:

[0020] Step 1: produce the upper connecting flange 1 by a forging manufacturing process, and produce the upper main body pipe 2 by a forging manufacturing process or a tube rolling manufacturing process;

[0021] Step 2: Using an argon arc welding method, the upper connecting flange 1 and the main pipe 2 are connected by welding into one piece; or the upper connecting flange 1 and the main pipe 2 are formed at one time by a forging manufacturing process;

[0022] Step 3: metallurgically forming an outer reinforcement layer 3 on the outer surface of the main tube 2 by 3D powder metallurgy forming technology, and the outer reinforcement layer 3 needs to reserve a margin for subsequent mechanical finishing;

[0023] 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;

[0024] Step 5: Mechanical finishing of the outer dimensions of the semi-finished product described in step 5.

[0025] The outer reinforcement layer of the utility model adopts ASTM B 265Gr-23 or Gr-29 titanium material, which is a high-performance titanium alloy material with good mechanical properties, such as low elastic modulus and good fatigue strength. When attached to the surface of the main pipe, the mechanical strength of the tapered stress joint can be increased, so that it can withstand more loads without being easily broken. At the same time, it also has excellent corrosion resistance and can withstand the corrosion of high-temperature chlorides, sulfides, ammonia and other media during seabed operations.

Claims

1. A tapered stress joint of composite material structure for butt welding risers, characterized in that: It comprises a main body pipe (2) and an upper connecting flange (1) fixed to the top of the main body pipe (2) for connecting to an offshore oil and gas resource exploitation platform. A titanium alloy outer reinforcement layer (3) with a successively decreasing thickness is metallurgically attached to the outer surface of the main body pipe (2).

2. The tapered stress joint of composite material structure for butt welding riser according to claim 1, characterized in that: The cross-section line of the outer reinforcement layer (3) is parabolic.

3. The tapered stress joint of composite material structure for butt welding riser according to claim 1, characterized in that: The material of the upper connecting flange (1) is F56 forging material of ASTM A694, the material of the main pipe (2) is 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 material structure for butt welding risers according to claim 1, 2 or 3, characterized in that: The upper connecting flange (1) and the main body pipe (2) are an integrally formed structure.

5. The tapered stress joint of composite material structure for butt welding risers according to claim 1, 2 or 3, characterized in that: The upper connecting flange (1) is fixed to the main pipe (2) by welding.

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