Low-phosphorus corrosion-resistant high-strength composite duplex stainless steel pipe

Abstract

The utility model provides a low-phosphorus corrosion-resistant high-strength composite duplex stainless steel pipe which comprises a phosphorus composite duplex stainless steel pipe, a high-strength middle-layer pipe is compounded outside a core pipe, and a corrosion-resistant outer-layer pipe is compounded outside the high-strength middle-layer pipe; by means of the overall arrangement, after the two low-phosphorus composite duplex stainless steel pipes are in butt joint, multiple sealing treatment can be conducted on the connecting position, welding seams can be protected and prevented from being corroded, and therefore the safety and reliability of conveying media are guaranteed.

Description

TECHNICAL FIELD

[0001] The utility model relates to duplex stainless steel pipe field especially relates to low phosphorus corrosion -resistant high strength composite duplex stainless steel pipe. BACKGROUND

[0002] Low phosphorus corrosion -resistant high strength composite duplex stainless steel pipe is a kind of stainless steel pipe material with austenite and ferrite two-phase structure, and its phosphorus content is lower.

[0003] It is known that when welding stainless steel pipe material, corresponding weld will be generated, since weld is relatively easy to compare corrosion, so in the process of conveying medium, security risk is prone to exist.

[0004] Therefore, it is very necessary to invent low phosphorus corrosion -resistant high strength composite duplex stainless steel pipe. INVENTION CONTENTS

[0005] In order to solve the above technical problems, the utility model provides low phosphorus corrosion -resistant high strength composite duplex stainless steel pipe adopts technical scheme: low phosphorus corrosion -resistant high strength composite duplex stainless steel pipe, including low phosphorus composite duplex stainless steel pipe, high-strength middle layer pipe is compounded outside the core pipe, anticorrosion outer layer pipe is compounded outside the high-strength middle layer pipe,

[0006] Preferably, one end of the core pipe is exposed from one end of the high-strength middle layer pipe and the anticorrosion outer layer pipe, the other end of the core pipe is hidden inside the other end of the high-strength middle layer pipe, the core pipe is hidden at one end of the high-strength middle layer pipe, the distance from the other end of the high-strength middle layer pipe to the hidden end of the core pipe is the same as the length of the exposed end of the core pipe from the high-strength middle layer pipe and the anticorrosion outer layer pipe, so that the composite duplex stainless steel pipe forms a socket joint structure at both ends for butt joint between two low phosphorus composite duplex stainless steel pipes.

[0007] Preferably, both ends of the high-strength middle layer pipe are exposed from both ends of the anticorrosion outer layer pipe.

[0008] Preferably, a sealing sleeve is fixedly installed on the outer part of the connection between the two low phosphorus composite duplex stainless steel pipes.

[0009] Preferably, one end between the anticorrosion outer layer pipe and the high-strength middle layer pipe is provided with a sealing cavity one, the other end between the anticorrosion outer layer pipe and the high-strength middle layer pipe is provided with a sealing cavity two, the sealing cavity one is on the same side with the exposed end of the core pipe, the sealing cavity two is on the same side with the unexposed end of the core pipe, the length of the sealing cavity one is greater than the length of the sealing cavity two, a part of the sealing sleeve is installed in the sealing cavity one and a part is exposed outside the sealing cavity one in the initial state, and the sealing sleeve is used for sealing and connecting the sealing cavity one and the sealing cavity two between the two low phosphorus composite duplex stainless steel pipes.

[0010] Preferably, the anticorrosion outer layer pipe is provided with a chamfer one at both ends, which is used for forming an outer welding groove after the butt joint of the two low-phosphorus composite duplex stainless steel pipes.

[0011] Preferably, the high-strength middle layer pipe is provided with a chamfer two at both ends, which is used for forming an inner welding groove after the butt joint of the two low-phosphorus composite duplex stainless steel pipes.

[0012] Preferably, a sealing gasket is fixedly installed between the connecting portions of the two low-phosphorus composite duplex stainless steel pipes.

[0013] Preferably, the outer surface of the sealing cylinder is provided with external threads, and the sealing cylinder is threadedly and sealingly connected between the corresponding sealing cavities one and two.

[0014] Compared with the prior art, the utility model has the advantages that:

[0015] The utility model discloses the whole setting, after the butt joint of two low-phosphorus composite duplex stainless steel pipes, not only can pass the connecting portion, carry out multiple sealing treatment, and can protect the welding seam, avoid the corrosion of the welding seam, thereby guaranteeing the safety and reliability of the conveying medium. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is the non-butt joint structure schematic view of the two low-phosphorus composite duplex stainless steel pipes of the utility model.

[0017] Figure 2 It is the preliminary butt joint structure schematic view of the two low-phosphorus composite duplex stainless steel pipes of the utility model.

[0018] Figure 3 It is the complete butt joint structure schematic view of the two low-phosphorus composite duplex stainless steel pipes of the utility model.

[0019] Figure 4 It is the full section structure schematic view of the butt joint of the two low-phosphorus composite duplex stainless steel pipes of the utility model.

[0020] Figure 5 It is the local enlarged structure schematic view of A of the utility model.

[0021] In the drawing:

[0022] Anticorrosion outer layer pipe 1, high-strength middle layer pipe 2, core pipe 3, sealing cylinder 4, sealing cavity one 5, sealing cavity two 6, chamfer one 7, chamfer two 8, sealing gasket 9, inner welding groove 10. DETAILED DESCRIPTION

[0023] In order to make the person skilled in the art better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0024] In the description of the embodiments, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, 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. In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of the present application, it should be noted that unless otherwise specified and limited, the terms "mounting", "provided with", "connection" and the like should be broadly understood, for example, "connection" can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0025] The present application will be further described below in conjunction with the drawings:

[0026] Embodiments

[0027] Reference Figures 1-5 , low-phosphorus corrosion-resistant high-strength composite duplex stainless steel pipe, comprising a low-phosphorus composite duplex stainless steel pipe, wherein: the low-phosphorus composite duplex stainless steel pipe comprises a corrosion-resistant outer pipe 1, a high-strength middle pipe 2 and a core pipe 3, the core pipe 3 is externally compounded with the high-strength middle pipe 2, and the high-strength middle pipe 2 is externally compounded with the corrosion-resistant outer pipe 1. By arranging the corrosion-resistant outer pipe 1 and the high-strength middle pipe 2, the outer part of the core pipe 3 can be protected, and the strength and corrosion resistance of the core pipe 3 can be improved.

[0028] One end of the core pipe 3 is exposed from one end of the high-strength middle layer pipe 2 and the corrosion-resistant outer layer pipe 1, and the other end of the core pipe 3 is hidden inside the other end of the high-strength middle layer pipe 2. The core pipe 3 is hidden at one end of the high-strength middle layer pipe 2, and the distance from the other end of the high-strength middle layer pipe 2 to the outside is the same as the length of the exposed end of the core pipe 3 from the high-strength middle layer pipe 2 and the corrosion-resistant outer layer pipe 1. Through the arrangement of the above structure, the socket joint structure can be formed at both ends of the composite duplex stainless steel pipe, so that the two low-phosphorus composite duplex stainless steel pipes can be butt jointed.

[0029] The inner and outer surfaces of the core pipe 3 are subjected to corrosion-resistant treatment.

[0030] Both ends of the high-strength middle layer pipe 2 are exposed from both ends of the corrosion-resistant outer layer pipe 1, and both ends of the high-strength middle layer pipe 2 are provided with chamfers 8 for forming inner welding grooves 10 after the two low-phosphorus composite duplex stainless steel pipes are butt jointed, so that the first sealing weld is formed after the high-strength middle layer pipes 2 are welded.

[0031] A sealing cylinder 4 is fixedly installed on the outer coaxial sealing sleeve at the connection of the two low-phosphorus composite duplex stainless steel pipes, so that the sealing cylinder 4 can seal and wrap the welding seam between the high-strength middle layer pipes 2 after the high-strength middle layer pipes 2 are welded, thereby avoiding the welding seam from being in contact with the external air.

[0032] In this embodiment, one end between the corrosion-resistant outer layer pipe 1 and the high-strength middle layer pipe 2 is provided with a sealing cavity 5, which provides installation space for the sealing cylinder 4 when the two low-phosphorus composite duplex stainless steel pipes are not connected, and does not affect the butt joint of the two low-phosphorus composite duplex stainless steel pipes in the later period. The other end between the corrosion-resistant outer layer pipe 1 and the high-strength middle layer pipe 2 is provided with a sealing cavity 6, so that the sealing cylinder 4 can seal and connect the sealing cavity 6 and the sealing cavity 5 after the two low-phosphorus composite duplex stainless steel pipes are butt jointed. The sealing cavity 5 is on the same side as the exposed end of the core pipe 3, and the sealing cavity 6 is on the same side as the unexposed end of the core pipe 3. The length of the sealing cavity 5 is greater than the length of the sealing cavity 6. In the initial state, part of the sealing cylinder 4 is installed in the sealing cavity 5 by screwing, and part of the sealing cylinder 4 is exposed outside the sealing cavity 5. The exposed length of the sealing cylinder 4 is less than the length of the high-strength middle layer pipe 2 exposed from the corrosion-resistant outer layer pipe 1. After one end of the sealing cylinder 4 enters the sealing cavity 6, the other end of the sealing cylinder 4 will not move out of the sealing cavity 5. The sealing cylinder 4 is used to seal and connect the sealing cavity 5 and the sealing cavity 6 between the two low-phosphorus composite duplex stainless steel pipes.

[0033] In this embodiment, both ends of the corrosion-resistant outer layer pipe 1 are provided with chamfers 7 for forming outer welding grooves after the two low-phosphorus composite duplex stainless steel pipes are butt jointed, so that the second sealing weld is formed after the corrosion-resistant outer layer pipes 1 are welded. In this way, even if the second sealing weld is corroded, it will not affect the first weld.

[0034] In this embodiment, a sealing gasket 9 is fixedly installed between the connection points of the two low-phosphorus composite duplex stainless steel pipes.

[0035] In this embodiment, the outer surface of the sealing cylinder 4 is provided with external threads, and the sealing chamber 1 5 and the sealing chamber 2 6 are provided with internal threads corresponding to the external threads.

[0036] It should be noted that the main chemical components of low-phosphorus corrosion-resistant high-strength composite duplex stainless steel pipes include iron (Fe), chromium (Cr), nickel (Ni), molybdenum (Mo), nitrogen (N) and other alloying elements, while ensuring that the phosphorus (P) content is low.

[0037] In order to ensure the corrosion resistance and high strength of low-phosphorus composite duplex stainless steel pipes during use, the alloy can be optimized as follows:

[0038] Increase the chromium (Cr) content: Chromium is the main corrosion-resistant element in stainless steel. By increasing the chromium content, the oxidation resistance of stainless steel can be improved, thereby showing better corrosion resistance in a variety of corrosive environments.

[0039] Adjusting the nickel (Ni) content: Nickel helps form the austenite phase, improving the toughness and corrosion resistance of the material. By adjusting the nickel content, the ratio of austenite to ferrite in duplex stainless steel can be optimized, thereby achieving better overall performance.

[0040] Adding molybdenum (Mo) element: Molybdenum element can enhance the resistance of stainless steel to corrosive media such as chlorides, and is particularly suitable for marine environments or environments containing chloride ions.

[0041] Controlling phosphorus (P) content: Although phosphorus can improve the strength and hardness of stainless steel, excessive phosphorus content can reduce the material's plasticity and toughness. Therefore, while maintaining a certain strength, the phosphorus content should be reduced as much as possible to improve the material's corrosion resistance and weldability.

[0042] Coating treatment: Applying a layer of corrosion-resistant coating (such as epoxy resin, polyurethane, etc.) on the surface of stainless steel can further isolate the external corrosive medium and provide an additional layer of protection.

[0043] The utility model discloses, specific use time, before docking, place the corresponding sealing washer 9 at the docking of two low phosphorus composite duplex stainless steel pipes, then let one low phosphorus composite duplex stainless steel pipe leak out the one end of core pipe 3 and insert in the one end of core pipe 3 of another low phosphorus composite duplex stainless steel pipe, the docking of two low phosphorus composite duplex stainless steel pipes can form inner welding bevel 10 and outer welding bevel at this time, first carry out welding at inner welding bevel 10, after welding, rotate sealing cylinder 4 clockwise, until the one end of sealing cylinder 4 enters sealing cavity two 6 and can not rotate, then carry out welding to outer welding bevel.

[0044] Utilize the technical scheme in the utility model, or the technical personnel in the utility model technical scheme are inspired, design similar technical scheme, and reach the above technical effect, all are fall in the protection scope of the utility model.

Claims

1. Low-phosphorus corrosion-resistant high-strength composite duplex stainless steel pipe, characterized by: The invention comprises a low-phosphorus composite duplex stainless steel pipe, wherein: the low-phosphorus composite duplex stainless steel pipe comprises an anti-corrosion outer layer pipe (1), a high-strength middle layer pipe (2) and a core pipe (3); the core pipe (3) is externally composited with the high-strength middle layer pipe (2); and the high-strength middle layer pipe (2) is externally composited with the anti-corrosion outer layer pipe (1); One end of the core tube (3) is exposed from one end of the high-strength middle layer tube (2) and the anti-corrosion outer layer tube (1), and the other end of the core tube (3) is hidden inside the other end of the high-strength middle layer tube (2); The core tube (3) is hidden in one end of the high-strength middle tube (2), and the distance from the outside of the other end of the high-strength middle tube (2) is the same as the length of the end of the core tube (3) exposed from the high-strength middle tube (2) and the anti-corrosion outer tube (1), so that the two ends of the composite duplex stainless steel pipe form a socket structure for docking the two low-phosphorus composite duplex stainless steel pipes; Both ends of the high-strength middle layer pipe (2) are exposed from both ends of the anti-corrosion outer layer pipe (1); The external coaxial sealing sleeve at the connection of the two low-phosphorus composite duplex stainless steel pipes is fixedly mounted with a sealing cylinder (4).

2. The low-phosphorus corrosion-resistant high-strength composite duplex stainless steel pipe according to claim 1, characterized in that: A sealing cavity one (5) is provided at one end between the anti-corrosion outer layer tube (1) and the high-strength middle layer tube (2), and a sealing cavity two (6) is provided at the other end between the anti-corrosion outer layer tube (1) and the high-strength middle layer tube (2). The sealing cavity one (5) is on the same side as the exposed end of the core tube (3), and the sealing cavity two (6) is on the same side as the unexposed end of the core tube (3). The length of the sealing cavity one (5) is greater than the length of the sealing cavity two (6). In the initial state, a portion of the sealing cylinder (4) is installed in the sealing cavity one (5) by means of a thread, and a portion is exposed outside the sealing cavity one (5). The sealing cylinder (4) is used for sealingly connecting the sealing cavity one (5) and the sealing cavity two (6) between the two low-phosphorus composite duplex stainless steel tubes.

3. The low-phosphorus corrosion-resistant high-strength composite duplex stainless steel pipe according to claim 1 or 2, characterized in that: Both ends of the anti-corrosion outer layer pipe (1) are provided with a chamfer (7), and the chamfer (7) is used to form an external welding groove after the two low-phosphorus composite duplex stainless steel pipes are butt-jointed.

4. The low-phosphorus corrosion-resistant high-strength composite duplex stainless steel pipe according to claim 1 or 2, characterized in that: Both ends of the high-strength middle layer tube (2) are provided with chamfers (8), and the chamfers (8) are used to form an internal welding groove (10) after the two low-phosphorus composite duplex stainless steel tubes are butt-jointed.

5. The low-phosphorus corrosion-resistant high-strength composite duplex stainless steel pipe according to claim 1, characterized in that: A sealing gasket (9) is fixedly installed between the connection points of the two low-phosphorus composite duplex stainless steel pipes.

6. The low-phosphorus corrosion-resistant high-strength composite duplex stainless steel pipe according to claim 2, characterized in that: The outer surface of the sealing cylinder (4) is provided with an external thread, and the sealing cylinder (4) is thread-sealed with the corresponding sealing cavity 1 (5) and sealing cavity 2 (6) via the external thread.

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