A method and device for testing the interface bonding strength of bimetallic composite pipes at ultra-low temperatures

Abstract

The present invention provides a method and device for testing the interface bonding strength of a bimetallic composite pipe at ultra-low temperature, and belongs to the technical field of composite pipe interface performance testing. First, the bimetallic composite pipe with inner and outer grooves is placed on the inner pipe and outer pipe chucks for positioning; then, the ultra-low temperature medium is filled in the annular cold-keeping groove inside the load-bearing beam, and spray cooling is performed; when the cooling temperature reaches the test temperature, two servo motors are used to drive the inner pipe and outer pipe chucks to rotate respectively, so that the test pipe undergoes in-plane shear deformation at the interface joint, and the physical parameters such as the shear interface bonding strength, interface displacement and rotation angle are recorded respectively by a torque sensor and a high-speed camera. The present invention provides a method and device for testing the interface bonding strength of a bimetallic composite pipe at ultra-low temperature, which has the advantages of compact structure, high process integration, strong versatility, and cylinder-frame-box integrated design, and solves the problem that the interface bonding strength and deformation of the composite pipe in ultra-low temperature environment are difficult to accurately measure.

Description

Technical Field

[0001] The invention belongs to the technical field of bimetallic composite pipe interface bonding performance testing, and specifically relates to a method and a device for testing the interface bonding performance of a steel-nickel bimetallic composite pipe in an ultra-low temperature service environment. Background Art

[0002] As the exploitation of oil and gas resources develops towards the fields of strong corrosion, high salinity and low temperature in the deep sea, ordinary carbon steel pipes can no longer meet the needs of harsh service environments. The use of nickel-based bimetallic composite pipes can effectively improve the low temperature resistance and corrosion resistance of pipes, and are widely used in offshore and onshore oil and gas field construction, low-temperature oil and gas transportation, and low-temperature fuel pressure filling. Such pipes usually serve under extremely low temperatures and dynamic load conditions, and have high requirements for their interface bonding strength. However, traditional detection methods are difficult to accurately quantify the interface bonding performance of nickel-based composite pipes under extremely low temperatures and dynamic load conditions. In order to solve the above problems, the present invention provides a method and device for testing the interface bonding strength of bimetallic composite pipes at ultra-low temperatures. The method has the advantages of compact structure, high process integration, and strong versatility. It realizes the monitorability of interface deformation during the entire process of composite pipe detection, and solves the problem that the interface strength of nickel-based bimetallic composite pipes in the service process of ultra-low temperature environments is difficult to accurately measure.

[0003] It is difficult to test the interface bonding strength between ordinary carbon steel pipe and nickel-based bimetallic composite pipe. In the existing technology, the test difficulties lie in: how to fix the bimetallic composite pipe, the implementation method of internal shear, external shear and internal and external mixed shear of the composite pipe, the ultra-low temperature service environment and insulation method, the monitorability of the bonding interface strength and deformation, etc. Summary of the invention

[0004] The present invention proposes a method and device for testing the interface bonding strength of a bimetallic composite pipe at ultra-low temperature, aiming to solve the main problems existing in the prior art: the bimetallic composite pipe is difficult to fix, the internal shear, external shear and internal and external mixed shear actions of the composite pipe and the ultra-low temperature service environment are difficult to achieve, and the interface bonding strength and deformation law are difficult to monitor.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is to propose a method and device for testing the interface bonding strength of a steel-nickel bimetallic composite pipe at ultra-low temperature. The device mainly comprises a "convex-concave cross-shaped" test composite pipe, an inner pipe chuck, an outer pipe chuck, a servo motor, a cylinder-beam-box assembly, a cold storage box, a high-speed camera, a torque sensor, a thermal resistor, and an ultra-low temperature cooling medium.

[0006] Before the test, the "convex and concave cross-shaped" test composite tube is placed on the inner tube clamp and the outer tube clamp for positioning; then, the ultra-low temperature medium is filled in the cold preservation box inside the load-bearing beam, and the side of the positioned test tube is sprayed and cooled using the annularly distributed nozzles; when the cooling temperature of the entire test tube reaches the temperature to be tested, the inner tube clamp and the outer tube clamp are driven to rotate by the left and right servo motors respectively, so that the test tube undergoes in-plane shear deformation at the interface joint, and the interface bonding strength and temperature are recorded respectively by the torque sensor and thermistor; at the same time, the high-speed camera is turned on to record key parameters such as the interface displacement and rotation angle during the in-plane shear process of the composite tube.

[0007] The entire testing process can be divided into three stages: installation and positioning of the test composite pipe, ultra-low temperature cooling and temperature measurement, and composite pipe interface shear deformation and parameter measurement. Specifically, it includes the following steps:

[0008] Step S1: Cut a small section of test tube from the steel-nickel bimetallic composite tube;

[0009] Step 2 S2: bonding grooves of a certain depth are processed along the axial direction on the inner and outer surfaces of the test tube to produce a "convex-concave cross-shaped" test composite tube;

[0010] Step 3 S3: placing the manufactured “convex-concave cross-shaped” test tube on the inner tube chuck and the outer tube chuck for positioning so that its axis coincides with the axis of the inner and outer chucks;

[0011] Step 4 S4: Filling the cold preservation box inside the cylinder-beam-box assembly with ultra-low temperature medium through a nozzle to make its temperature reach the ultra-low temperature service temperature of the composite pipe;

[0012] Step 5 S5: Turn on the left and right servo motors, gradually add torsional force, drive the inner tube chuck and the outer tube chuck to rotate, so that they undergo in-plane shear deformation at the interface joint;

[0013] Step 6 S6: observing the interface deformation and separation phenomenon of the composite tube in the shearing process through a high-speed camera in the front glass window;

[0014] Step 7 S7: recording parameters such as torque, torsion angle and interface displacement when the composite tube interface is separated;

[0015] Step 8 S8: After the interface of the composite pipe is rotated and separated, the servo motor is turned off, and the tested composite pipe section is disassembled and taken out from the fixture.

[0016] Compared with the prior art, the beneficial effects of the present invention are: a method and device for testing the interface bonding strength of bimetallic composite pipes at ultra-low temperatures are proposed. The "convex-concave cross-shaped" test composite pipe and the inner and outer pipe clamps are mainly designed; the front cylinder-load-bearing beam-rear cylinder combination structure is adopted to realize the integration of the front cylinder observation test, beam load-bearing, rear cylinder power supply and heat preservation functions; torque sensors are installed at the left and right ends to obtain the interface bonding force of the composite pipe; two independent servo motors are used to drive the rotation of the inner and outer pipes respectively, realizing the functions of internal shearing, external shearing and internal and external mixed shearing of the composite pipe.

[0017] This method solves the problem of the difficulty in accurately measuring the interface strength between ordinary carbon steel pipes and nickel-based bimetallic composite pipes at ultra-low temperatures, and has the advantages of compact structure, high process integration, and good interface visibility. Composite pipes of different types and diameters can be tested without changing the main structure of the equipment, and it has strong versatility, solving the problem of the difficulty in accurately measuring the interface strength of nickel-based bimetallic composite pipes during service in ultra-low temperature environments, and the difficulty in observing interface deformation and damage laws in ultra-low temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the implementation scheme of the method and device for testing the interface bonding strength of ordinary carbon steel pipe and nickel-based bimetallic composite pipe at ultra-low temperature of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0019] Figure 1 is a schematic diagram of the selected composite pipe structure;

[0020] Figure 2 This is the processed "convex-concave cross-shaped" composite pipe specimen;

[0021] Figure 3 This is a schematic diagram of the composite pipe specimen and its fixture structure after processing;

[0022] Figure 4 are main reference numerals and a schematic diagram of a test device;

[0023] Main figure marks: 1 high-speed camera; 2 glass window; 3 front cylinder; 4 load-bearing beam; 5 rolling bearing; 6 nozzle; 7 cold storage box; 8 rear cylinder; 9 right chuck; 10 right torque sensor; 11 right servo motor; 12 ultra-low temperature medium; 13 low-temperature steel pipe; 14 thermal resistor; 15 left chuck; 16 left torque sensor; 17 left servo motor; 18 inner tube chuck; 19 rotating arm; 20 nickel-based composite layer; 21 outer tube chuck. DETAILED DESCRIPTION

[0024] The above and other technical features and advantages of the present invention are described in more detail below in conjunction with the accompanying drawings.

[0025] See also Figure 2 , Figure 3 and Figure 4 .

[0026] The present invention proposes a method and device for testing the interface bonding strength of bimetallic composite pipes at ultra-low temperatures. Through the designed "convex-concave cross-shaped" test composite pipe and the chucks for independently rotating inner and outer pipes, and with the help of the front cylinder-load-bearing beam-rear cylinder combined structure, the front cylinder observation test, beam load-bearing, rear cylinder power supply, and internal shearing, external shearing, and internal and external mixed shearing of the composite pipe are realized.

[0027] The basic components of this test device mainly include: high-speed camera 1; glass window 2; front cylinder 3; load-bearing beam 4; rolling bearing 5; nozzle 6; cold storage box 7; rear cylinder 8; right chuck 9; right torque sensor 10; right servo motor 11; ultra-low temperature medium 12; low-temperature steel pipe 13; thermal resistor 14; left chuck 15; left torque sensor 16; left servo motor 17; inner tube clamp 18; rotating arm 19; nickel-based composite layer 20; outer tube clamp 21, etc. The main working steps are as follows:

[0028] A small section of test tube is cut from the steel-nickel bimetallic composite tube, and bonding grooves of a certain depth are processed along the axial direction of the test tube to produce a "convex-concave cross-shaped" test composite tube; the produced test tube is placed on the inner tube clamp 18 and the outer tube clamp 21 for positioning so that its axis coincides with the axis of the inner and outer clamps; the ultra-low temperature medium 12 is filled in the cold-keeping box 7 in the rear cylinder 8 through the nozzle 6 so that its temperature reaches the ultra-low temperature service temperature of the composite tube.

[0029] Composite pipe internal shearing embodiment

[0030] The right servo motor 11 is turned on, and the torsional force is gradually increased. The inner tube chuck 18 is driven to rotate by the right chuck 9, and the outer tube chuck 21 is fixed by the left chuck 15, so that the nickel-based layer 20 of the experimental composite tube undergoes inner tube shear deformation at the interface joint; the interface deformation and separation phenomenon of the nickel-based layer 20 of the composite tube during the internal shear process are observed through the high-speed camera 1 of the glass window 2 of the front cylinder 3; and the parameters such as the torque, torsion angle and interface displacement during the separation of the composite tube interface are recorded.

[0031] Composite pipe external shearing embodiment

[0032] The left servo motor 17 is turned on, and the torsional force is gradually increased. The outer tube chuck 21 is driven to rotate through the left chuck 15, and the inner tube chuck 18 is fixed through the right chuck 9, so that the outer tube shear deformation of the experimental composite tube occurs at the interface joint of the ordinary carbon steel tube 13; the interface deformation and separation phenomenon of the composite tube and the ordinary carbon steel tube 13 during the external shear process are observed through the high-speed camera 1 of the glass window 2 of the front cylinder 3; and the parameters such as the torque, torsion angle and interface displacement when the composite tube interface is separated are recorded.

[0033] Composite pipe internal and external mixed shearing embodiment

[0034] Turn on the left servo motor 17 and the right servo motor 11 at the same time, and increase the torsional force step by step; drive the outer tube clamp 21 to rotate counterclockwise through the left chuck 15, and drive the inner tube clamp 18 to rotate clockwise through the right chuck 9, so that the experimental composite tube undergoes mixed shear deformation of the inner and outer tubes at the interface of the ordinary carbon steel tube 13 and the nickel-based layer 20; observe the interface deformation and separation phenomenon of the ordinary carbon steel tube 13 and the nickel-based layer 20 of the composite tube through the high-speed camera 1 of the glass window 2 of the front cylinder 3; record the torque, torsion angle, interface displacement and other parameters when the interface of the ordinary carbon steel tube 13 and the nickel-based layer 20 is separated; after the composite tube interface is rotated and separated, turn off the left servo motor 17 and the right servo motor 11, and disassemble and remove the tested composite tube section from the fixture.

[0035] In summary, the present invention provides a method and device for testing the interface bonding strength of a bimetallic composite pipe at ultra-low temperature. Before the test, a section of the test pipe is first cut from the composite pipe, and a "cross" bonding groove of a certain depth is processed axially on the inner and outer surfaces of the test pipe, and then the test composite pipe is placed on the inner pipe clamp 18 and the outer pipe clamp 21 for positioning; then the ultra-low temperature medium 12 is filled in the cold preservation box 7, and the side of the positioned test pipe is sprayed and cooled by the annularly distributed nozzles 6; when the cooling temperature of the entire test pipe reaches the temperature to be tested, the inner pipe clamp 18 and the outer pipe clamp 21 are driven to rotate by the left servo motor 17 and the right servo motor 11 respectively, so that the test pipe undergoes in-plane shear deformation at the interface joint; the left torque sensor 16, the right torque sensor 10, and the thermal resistor 14 are used to record the interface bonding strength and temperature respectively; at the same time, the high-speed camera 1 is turned on to record the whole process of separation of the interface between the composite pipe layers, and the key parameters such as the interface displacement and rotation angle of the composite pipe in-plane shear process are recorded.

[0036] The present invention provides a method and device for testing the interface bonding strength of bimetallic composite pipes at ultra-low temperatures. The method solves the problem that the interface bonding strength of ordinary carbon steel pipes and nickel-based bimetallic composite pipes at ultra-low temperatures is difficult to accurately measure, and has the advantages of compact structure, high process integration, good interface visibility, cylinder-frame-box integrated design, etc. Composite pipes of different types and diameters can be tested without changing the main structure of the equipment, and have strong versatility; in addition, the method and device are of great significance to the research on the interface strength, deformation law and damage and cracking of composite pipes during ultra-low temperature service.

[0037] The above description is only a preferred implementation mode of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments or replace part or all of the technical features therein with equivalents, and these modifications and replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for testing the interface bonding strength of a bimetallic composite pipe at ultra-low temperature, characterized in that: The specific steps include: S1: A section of the steel-nickel composite tube is cut as a test tube; S2: Processing a cross-shaped keying groove of a certain depth along the axial direction on the inner and outer surfaces of the test tube; S3: placing the test tube treated in S2 in the test device, positioning the key groove on the inner surface of the test tube by the inner tube chuck, positioning the key groove on the outer surface of the test tube by the outer tube chuck, so that the axis of the test tube coincides with the axis of the inner tube chuck and the axis of the outer tube chuck; S4: A cold-keeping box filled with ultra-low temperature medium is provided inside the test device formed by the cylinder-beam-box assembly; S5: spray cooling treatment of the end surface of the test tube with ultra-low temperature medium through the nozzle in the cold preservation box to simulate the ultra-low temperature service temperature of the test tube; S6: After the cooling in S5 is completed, the servo motor of the test device is turned on, and the torsional force is gradually increased to drive the inner tube chuck and / or the outer tube chuck to rotate, so that the test tube undergoes inner tube shear deformation, outer tube shear deformation, or mixed inner tube and outer tube shear deformation at the interface joint; S7: Observe the interface deformation and separation phenomenon of the test tube during the shearing process through a high-speed camera arranged on the front glass window of the test device; record the torque, torsion angle, and interface displacement parameters when the test tube interface separates; S8: After the test tube interface is rotated and separated, the Dewar flask and the servo motor of the test device are turned off, and the test tube after the test separation is disassembled and taken out from the inner tube chuck and the outer tube chuck.

2. According to claim 1, a method for testing the interface bonding strength of a bimetallic composite pipe at ultra-low temperature, characterized in that: The test device formed by the cylinder-beam-box combination in S4 comprises: a box body, wherein the box body is connected to a front cylinder (3), a load-bearing beam (4) and a rear cylinder (8) in sequence from left to right; the front cylinder (3) is connected to a left servo motor (17), a left torque sensor (16), a left chuck (15) and a rotating arm (19) in sequence from left to right; the rotating arm (19) is connected to an outer tube clamp (21); the rear cylinder (8) is connected to a right servo motor (11), a right torque sensor (10) and a right chuck (9) in sequence from right to left; wherein a glass window (2) is arranged on the left side of the front cylinder (3); a high-speed camera (1) is installed outside the glass window (2); a cold-keeping box (7) is arranged in the rear cylinder (8) near the test tube; and the cold-keeping box (7) is filled with an ultra-low temperature medium (12) through a nozzle (6).

3. According to claim 2, a method for testing the interface bonding strength of a bimetallic composite pipe at ultra-low temperature, characterized in that: The inner and outer surfaces of the test tube are both provided with keying grooves of a certain depth, and the keying grooves are of a convex-concave cross-shaped structure, and the inner and outer surfaces of the test tube are clamped and positioned respectively by the outer wall shape of the inner tube clamp (18) and the inner wall shape of the outer tube clamp (21).

4. According to claim 2, a method for testing the interface bonding strength of a bimetallic composite pipe at ultra-low temperature, characterized in that: The test device integrates the load-bearing beam (4) for fixing the inner tube clamp (18) and the outer tube clamp (21), the cold-keeping box (7), and the front cylinder (3) and the rear cylinder (8) for installing the test tube, so as to realize the integration of the front cylinder (3) observation test, the beam bearing, and the rear cylinder (8) providing power and heat preservation functions.

5. According to claim 2, a method for testing the interface bonding strength of a bimetallic composite pipe at ultra-low temperature, characterized in that: The nozzles (6) are multiple and distributed in an annular manner, and the test tube, the inner tube clamp (18), and the outer tube clamp (21) are cooled as a whole, which can avoid uneven temperature distribution and improve the cooling efficiency of the test tube.

6. According to claim 2, a method for testing the interface bonding strength of a bimetallic composite pipe at ultra-low temperature, characterized in that: Two sets of rolling bearings (5) are designed, one inside and one outside, for rotational positioning of the inner tube clamp (18) and the outer tube clamp (21), and can also realize rotational shear deformation of the inner surface and the outer surface of the test tube.

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