Pipe end seal type metal composite bent pipe

Abstract

The utility model discloses a pipe end sealing type metal composite elbow, including base body elbow, lining elbow, intermediate metallurgical layer and pipe end sealing weld, the base body elbow is constituted by two end straight pipe section and intermediate curved section of center line not on the same straight line, is provided with lining elbow in the inside of base body elbow, and is used for metallurgical combination through setting up intermediate metallurgical layer between base body elbow and lining elbow, two ends of lining elbow respectively extend two ends of base body elbow and intermediate metallurgical layer, and the length of same side extension is 2.5 4mm, respectively welds and forms pipe end sealing weld at the alignment of the extension part, base body elbow, intermediate metallurgical layer and lining elbow, and lining elbow and base body elbow, intermediate metallurgical layer are sealedly connected through pipe end sealing weld, the problem that the absolute reliability and lining stability of existing composite elbow seal are low is solved, the overall sealing performance of composite elbow is improved significantly, and long -term stable operation under the environment of high pressure, high temperature and corrosive medium is ensured.

Description

Technical Field

[0001] This utility model belongs to the field of pipe connection, specifically relating to a metal composite bend with pipe end sealing welding. Background Technology

[0002] A bend is a pipe fitting used in a piping system to change the direction of fluid transport. It typically connects straight pipes at a specific angle to adapt to pipeline layouts, bypass obstacles, or meet the connection requirements of process equipment. It is a core component of industrial and civil pipelines. Currently, some existing bends are made of a single material, carbon steel or stainless steel. Carbon steel bends, while having strong pressure resistance and low price, are prone to corrosion. Stainless steel bends, although corrosion-resistant, have weak pressure resistance and are expensive. Composite bends, achieved through mechanical bonding or metallurgical bonding via welding, employ a bimetallic structure of "base layer + lining." The base layer (usually carbon steel or low-alloy steel) provides sufficient mechanical strength and rigidity to withstand high pressure, high temperature, and stress during bending. The lining (usually stainless steel, nickel-based alloys, or other corrosion-resistant materials) directly contacts the corrosive medium, isolating corrosion and protecting the pipeline, thus overcoming the shortcomings of single-layer bends.

[0003] Patent application No. 201120425967.6 discloses a bimetallic composite bend with metallurgical mechanical properties at both ends. A liner bend is provided inside the base bend. The distance between the end of the liner bend and the end of the base bend on the same side is 10-50 mm. The two ends of the liner bend and the two ends of the base bend are welded together to form a metallurgical bonding layer. However, the welding only forms a fused layer on the surface and cannot fix the bond between the liner and the base. During long-term use, the liner may fall off or bulge due to media erosion and temperature changes, affecting the corrosion resistance of the bend. Especially when conveying flammable, explosive, toxic, and highly corrosive media, the requirements for absolute reliability of the seal and stability of the liner are even higher. Utility Model Content

[0004] To overcome the shortcomings of the prior art, the purpose of this utility model is to provide a metal composite bend with pipe end sealing, which solves the problems of low absolute reliability of the seal and low lining stability of the existing composite bend.

[0005] This utility model is achieved through the following technical solution: A metal composite bend with end sealing weld includes a base bend, a liner bend, an intermediate metallurgical layer, and an end sealing weld. The base bend consists of two straight sections with centerlines not on the same straight line and a middle curved section. A liner bend is installed inside the base bend, and an intermediate metallurgical layer is provided between the base bend and the liner bend for metallurgical bonding. The two ends of the liner bend extend out of the base bend and the intermediate metallurgical layer, respectively, with an extension length of 2.5-4 mm on the same side. End sealing welds are formed at the alignment points of the extended portions, the base bend, the intermediate metallurgical layer, and the liner bend, respectively, sealing the liner bend, the base bend, and the intermediate metallurgical layer together.

[0006] Furthermore, the thickness t1 of the base bend is 5-25 mm, the thickness t2 of the liner bend is 1-3 mm, and the thickness t3 of the intermediate metallurgical layer is 0.1-0.3 mm.

[0007] Furthermore, the bending angle α of the middle bending section of the substrate bend is 3°-180°.

[0008] Furthermore, the straight section and the bent section of the base bend have the same inner diameter, the outer diameter D of the straight section at both ends of the base bend is 32-711 mm, and the bending radius R of the base bend is at least 1.5 times the outer diameter D of the base bend.

[0009] Furthermore, the length of the straight pipe sections at both ends of the base bend should be greater than 100mm, and the lengths of the straight pipe sections at both ends may be equal or unequal.

[0010] Furthermore, the intermediate metallurgical layer is made of nickel-based brazing layer or copper-based brazing layer material.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: The composite bend provided by this utility model achieves a strong bond between the two materials by setting an intermediate metallurgical layer between the base bend and the liner bend. This not only ensures the overall pressure-bearing capacity of the bend but also effectively improves its corrosion resistance and extends its service life. The design of the pipe end sealing weld significantly enhances the overall sealing performance of the composite bend, ensuring long-term stable operation under high pressure, high temperature, and corrosive media environments. The pipe end sealing weld not only achieves a strong connection between the base bend, the intermediate metallurgical layer, and the liner bend but also effectively prevents liner detachment caused by media erosion or temperature changes, further enhancing the bend's corrosion resistance and mechanical strength. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the base bend, the liner bend, and the intermediate metallurgical layer of this utility model. Figure 2 This is a schematic diagram of the overall structure of this utility model; In the diagram: 1-base bend, 2-liner bend, 3-intermediate metallurgical layer, 4-pipe end sealing weld, t1-thickness of base bend, t2-thickness of liner bend, t3-thickness of intermediate metallurgical layer, a-bending angle of the middle bend of the base bend, D-outer diameter of the straight pipe sections at both ends of the base bend, R-bending radius of the base bend, c-extension length of the liner bend, L1-length of the straight pipe section at one end of the base bend, L2-length of the straight pipe section at the other end of the base bend. Detailed Implementation

[0013] The present invention will be further described in detail below with reference to specific embodiments. The description is for explanation and not limitation of the present invention.

[0014] A metal composite bend with end sealing weld is composed of a base bend 1, a liner bend 2, an intermediate metallurgical layer 3, and an end sealing weld 4.

[0015] like Figure 1 As shown, the base bend 1 is composed of two straight pipe sections at both ends and a middle bend section whose center lines are not on the same straight line. A liner bend 2 is provided inside the base bend 1, and the base bend 1 and the liner bend 2 are metallurgically bonded through an intermediate metallurgical layer 3. The metallurgical bonding strength reaches more than 100MPa and the metallurgical bonding rate reaches 100%. The two ends of the liner bend 2 extend out of the base bend 1 and the two ends of the intermediate metallurgical layer 3, respectively, and the extension length c on the same side is 2.5-4mm.

[0016] like Figure 2 As shown, pipe end sealing welds 4 are formed by welding at the alignment points of the extended portion, the base bend 1, the intermediate metallurgical layer 3 and the liner bend 2, respectively. The liner bend 2, the base bend 1 and the intermediate metallurgical layer 3 are sealed and connected by the pipe end sealing welds 4.

[0017] The bending angle α of the middle bending section of the base bend 1 is 3°-180°; the lengths L1 and L2 of the straight pipe sections at both ends of the base bend 1 should be greater than 100mm, and the lengths L1 and L2 of the straight pipe sections at both ends can be equal or unequal; the bending radius R of the base bend 1 is at least 1.5 times the outer diameter D of the base bend 1; the inner diameters of the straight pipe sections and the bending sections of the base bend 1 are the same, and the outer diameter D of the straight pipe sections at both ends of the base bend 1 is 32-711mm.

[0018] The base bend 1 can be made of carbon steel or low alloy materials, and the thickness t1 of the base bend 1 can be 5-25mm; the liner bend 2 can be made of corrosion-resistant alloy materials or wear-resistant alloy materials (such as stainless steel, titanium alloy, copper alloy, etc.), and the thickness t2 of the liner bend 2 can be 1-3mm; the intermediate metallurgical layer 3 can be made of nickel-based brazing layer or copper-based brazing layer, and the thickness t3 of the intermediate metallurgical layer 3 is 0.1-0.3mm.

[0019] A metal composite bend with sealed ends is manufactured using the following steps: Step 1: The inner surface of the base straight pipe 1 is degreased, degreased, and sandblasted to achieve Sa2.5 level; Step 2: Degrease and grease the outer surface of the liner tube 2 and shot blast it with stainless steel to achieve a surface roughness of 30μm-60μm. Simultaneously, wrap the intermediate metallurgical layer 3 (such as nickel-based or copper-based brazing filler metal) around the outer surface. Step 3: With the assistance of the assembly tooling, the liner straight pipe 2 with the intermediate metallurgical layer 3 is assembled into the base straight pipe 1. The assembled base straight pipe 1 and liner straight pipe 2 are combined by explosive or hydraulic composite method to obtain a composite straight pipe with a brazing filler layer in the middle of the liner. Step 4: According to the brazing process of the intermediate metallurgical layer 3, the semi-finished product described in Step 3 is placed into a vacuum brazing equipment for metallurgical brazing to obtain a brazed metallurgical bonded metal composite straight pipe. Step 5: Place the brazed metal composite straight pipe described in Step 4 into a cold bending equipment and cold bend it to obtain a brazed metal composite bent pipe. Step Six: The two ends of the brazed metal composite bend described in Step Five are machined with outer bevels to remove a certain length of the base bend 1. The ends are then sealed by argon arc welding to form the pipe end sealing weld 4, thus obtaining a pipe end sealing weld type metal composite bend.

[0020] Example 1 A metal composite elbow with end sealing weld is composed of a base elbow 1, a liner elbow 2, an intermediate metallurgical layer 3, and an end sealing weld 4. The base elbow 1 consists of two straight pipe sections with centerlines not on the same straight line and a middle curved section. A liner elbow 2 is installed inside the base elbow 1, and the base elbow 1 and the liner elbow 2 are metallurgically bonded through the intermediate metallurgical layer 3, with a metallurgical bond strength of over 100 MPa and a metallurgical bond rate of 100%. The two ends of the liner elbow 2 extend out of the base elbow 1 and the intermediate metallurgical layer 3, respectively, with an extension length c of 2.5 mm on the same side. End sealing welds 4 are formed on the extended portions, at the alignment points of the base elbow 1, the intermediate metallurgical layer 3, and the liner elbow 2, respectively, sealing the liner elbow 2, the base elbow 1, and the intermediate metallurgical layer 3 through the end sealing welds 4.

[0021] The bending angle α of the middle bending section of the base bend pipe 1 is 45°; the lengths L1 and L2 of the straight pipe sections at both ends of the base bend pipe 1 are both 120 mm; the inner diameters of the straight pipe sections and the bending sections of the base bend pipe 1 are the same, and the outer diameter D of the straight pipe sections at both ends of the base bend pipe 1 is 150 mm; the bending radius R of the base bend pipe 1 is 1.5 times the outer diameter D of the base bend pipe 1.

[0022] The base bend 1 is made of ordinary carbon steel and has a thickness t1 of 5 mm; the liner bend 2 is made of stainless steel and has a thickness t2 of 1 mm; the intermediate metallurgical layer 3 is made of nickel-based brazing material and has a thickness t3 of 0.1 mm.

[0023] Example 2 A metal composite elbow with end sealing weld is composed of a base elbow 1, a liner elbow 2, an intermediate metallurgical layer 3, and an end sealing weld 4. The base elbow 1 consists of two straight pipe sections with centerlines not on the same straight line and a middle curved section. The liner elbow 2 is composite inside the base elbow 1, and the base elbow 1 and the liner elbow 2 are metallurgically bonded through the intermediate metallurgical layer 3, with a metallurgical bond strength of over 100 MPa and a metallurgical bond rate of 100%. The two ends of the liner elbow 2 extend out of the base elbow 1 and the intermediate metallurgical layer 3, respectively, with an extension length c of 4 mm on the same side. End sealing welds 4 are welded on the extended portions, at the alignment points of the base elbow 1, the intermediate metallurgical layer 3, and the liner elbow 2, respectively, to form a sealed connection between the liner elbow 2, the base elbow 1, and the intermediate metallurgical layer 3.

[0024] The bending angle α of the middle bending section of the base bend pipe 1 is 60°; the lengths L1 and L2 of the straight pipe sections at both ends of the base bend pipe 1 are 250 mm and 200 mm respectively; the inner diameters of the straight pipe sections and the bending sections of the base bend pipe 1 are the same, and the outer diameter D of the straight pipe sections at both ends of the base bend pipe 1 is 700 mm; the bending radius R of the base bend pipe 1 is 2.5 times the outer diameter D of the base bend pipe 1.

[0025] The base bend 1 is made of low alloy material and the thickness t1 of the base bend 1 is 25mm; the liner bend 2 is made of titanium alloy material and the thickness t2 of the liner bend 2 is 3mm; the intermediate metallurgical layer 3 is made of copper-based brazing layer material and the thickness t3 of the intermediate metallurgical layer 3 is 0.3mm.

Claims

1. A metal composite elbow with sealed ends, characterized in that, It includes a base bend (1), a liner bend (2), an intermediate metallurgical layer (3), and a pipe end sealing weld (4); the base bend (1) is composed of two straight pipe sections with center lines not on the same straight line and a middle bend section. A liner bend (2) is provided inside the base bend (1), and an intermediate metallurgical layer (3) is provided between the base bend (1) and the liner bend (2) for metallurgical bonding; the two ends of the liner bend (2) extend out of the base bend (1) and the two ends of the intermediate metallurgical layer (3) respectively, with an extension length of 2.5-4mm on the same side. On the extended part, at the alignment of the base bend (1), the intermediate metallurgical layer (3) and the liner bend (2), pipe end sealing welds (4) are formed respectively. The liner bend (2), the base bend (1), and the intermediate metallurgical layer (3) are sealed and connected by the pipe end sealing welds (4).

2. The end-sealed metal composite bend according to claim 1, characterized in that, The thickness t1 of the base bend (1) is 5-25mm, the thickness t2 of the liner bend (2) is 1-3mm, and the thickness t3 of the intermediate metallurgical layer (3) is 0.1-0.3mm.

3. The end-sealed metal composite bend according to claim 1, characterized in that, The bending angle α of the middle bending section of the base bend (1) is 3°-180°.

4. The end-sealed metal composite bend according to claim 1, characterized in that, The straight section and the curved section of the base bend (1) have the same inner diameter. The outer diameter D of the straight section at both ends of the base bend (1) is 32-711 mm. The bending radius R of the base bend (1) is at least 1.5 times the outer diameter D of the base bend (1).

5. The end-sealed metal composite bend according to claim 1, characterized in that, The length of the straight pipe sections at both ends of the base bend (1) should be greater than 100mm, and the lengths of the straight pipe sections at both ends may be equal or unequal.

6. The end-sealed metal composite bend according to claim 1, characterized in that, The intermediate metallurgical layer (3) is made of nickel-based brazing layer or copper-based brazing layer material.

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