Bimetal composite pipe bonding strength testing device and testing method

Abstract

The invention discloses a bimetal composite pipe bonding strength testing device and method. The bimetal composite pipe bonding strength testing device comprises a base, and a shearing mandrel, an outer cylinder and a power device are arranged on the base; the outer cylinder is fixed on the base, the outer cylinder is used for placing a to-be-tested composite tube sample, a plurality of grooves are formed in the inner surface of the outer cylinder, and the to-be-tested composite tube sample is fixed by the grooves; the outer cylinder and the shearing mandrel are coaxially arranged, the shearing mandrel is arranged close to one end of the outer cylinder, and the power device can drive the shearing mandrel to move in the axial direction of the outer cylinder and stretch into the outer cylinder; the composite pipe sample comprises an inner layer and an outer layer, and the shearing mandrel can apply shearing force to the inner layer of the composite pipe sample. Sampling can be conducted on a bimetal composite pipe product object, multiple samples taken from the same bimetal composite pipe can be tested at the same time under the same condition, the reliability and repeatability of test data are effectively judged, the outer cylinder is provided with the groove, the outer cylinder and the samples can be clamped and fixed, therefore, the samples are clamped stably, the device is convenient to operate, and the test efficiency is improved. The test efficiency is high.

Description

Technical Field

[0001] The invention relates to the field of bimetallic composite pipes, and in particular to a device and method for testing the bonding strength of bimetallic composite pipes. Background Art

[0002] Bimetallic composite pipes are usually composed of a carbon steel layer and a corrosion-resistant alloy layer. The carbon steel layer serves as the load-bearing body of the pipe body, and the corrosion-resistant layer serves as the corrosion-resistant body of the pipe body. Since bimetallic composite pipes have better cost-effectiveness than pure corrosion-resistant alloy pipes and have good anti-corrosion properties, they are alternative products to pure stainless steel pipes, copper pipes or other corrosion-resistant alloy pipes. They are increasingly used in the exploration, development and transportation of energy such as oil, natural gas, and coalbed methane, as well as in the water supply and drainage systems of livelihood projects. At present, there are many ways to composite bimetallic composite pipes, such as mechanical composite, cladding composite, plate welding metallurgical composite and seamless metallurgical composite. The bonding strength of bimetallic composite pipes is an important indicator for evaluating the performance of composite pipes. How to measure the bonding strength of bimetallic composite pipes has always been a common concern in the industry. At present, the bonding strength of composite pipes is required in standards such as GB / T 28897 "Steel-Plastic Composite Pipe" and SY / T 6855 "Bimetallic Composite Pipes for Gathering and Transportation Pipelines of Natural Gas Fields Containing H2S / CO2". In the above standards, specific requirements are put forward for the bonding strength test method, but there is no unified regulation on the test device in the standard, and there is no specific recommended practice. In terms of the test device and test method for the bonding strength of bimetallic composite pipes, many domestic units have proposed a number of different devices and corresponding test methods. The test methods mostly use flat specimens, and the test device is a single specimen, with low test efficiency, and it is impossible to judge the repeatability and reliability of the test results.

[0003] Therefore, it is urgent to provide a solution for a bimetallic composite pipe bonding strength testing device and a testing method. Summary of the invention

[0004] In order to solve the above problems, the technical solution of the present invention provides a bimetallic composite pipe bonding strength testing device and a testing method, which can improve the detection efficiency.

[0005] According to a first aspect of the technical solution of the present invention, there is provided a bimetallic composite pipe bonding strength testing device, comprising a base, on which a shear mandrel, an outer cylinder and a power device are provided;

[0006] The outer cylinder is fixed on the base, and the outer cylinder is used to place the composite pipe sample to be tested. The inner surface of the outer cylinder is provided with a plurality of grooves, and the grooves fix the composite pipe sample to be tested;

[0007] The outer cylinder is coaxially arranged with the shearing mandrel, the shearing mandrel is arranged close to one end of the outer cylinder, and the power device can drive the shearing mandrel to move along the axial direction of the outer cylinder and extend into the interior of the outer cylinder;

[0008] The composite pipe sample comprises an inner layer and an outer layer, and the shear mandrel can apply a shear force to the inner layer of the composite pipe sample.

[0009] In the above solution, the grooves are evenly distributed along the circumference of the inner surface of the outer cylinder.

[0010] In the above solution, the groove is a dovetail groove.

[0011] In the above solution, the groove opens from one end of the outer tube, is arranged along the axial direction, and extends to the other end of the outer tube and is blocked.

[0012] In the above solution, the distance between the end of the groove at the end blocked by the outer tube and the blocked end of the outer tube is greater than 20 mm.

[0013] In the above scheme, the power device includes a hydraulic cylinder and a hydraulic system. The hydraulic cylinder is fixedly arranged on the base, and the hydraulic system is connected to the hydraulic cylinder to drive the shear spindle to move.

[0014] In the above scheme, the outer diameter of the shear mandrel is 0 to 0.2 mm smaller than the inner diameter of the outer cylinder.

[0015] In the above solution, a lubricating layer is provided on the inner surface of the outer cylinder and the outer surface of the shearing mandrel.

[0016] According to a second aspect of the technical solution of the present invention, there is provided a testing method for a bimetallic composite pipe bonding strength testing device as described in any one of the above-mentioned solutions, comprising:

[0017] S1. Select the outer cylinder and shear mandrel according to the outer diameter and wall thickness of the composite tube to be tested;

[0018] S2. Cutting a plurality of composite tube samples from the composite tube to be tested according to the cross-sectional size, axial depth and number of the grooves of the outer tube;

[0019] S3, setting the axial length of the inner layer of the composite tube sample and the axial spacing of the inner layers between the composite tube samples;

[0020] S4, processing the inner layer of the composite tube sample according to the set value;

[0021] S5. Calculate the bonding interface area between the outer layer and the inner layer of the composite tube sample;

[0022] S6. Fix the composite tube samples in the grooves of the outer tube in sequence at equal intervals according to the positions of the remaining inner layers of the composite tube samples;

[0023] S7, starting the power device to drive the shearing mandrel to move axially along the outer cylinder to shear the inner layer of the composite tube sample, and recording the data value of the power device during shearing;

[0024] S8. Calculate the bonding strength between the outer layer and the inner layer of the composite tube sample according to the data value of the power device and the bonding interface area between the outer layer and the inner layer of the composite tube sample.

[0025] In the above scheme, the composite tube sample in step S2 is an arc-shaped columnar structure.

[0026] Beneficial effects of the present invention:

[0027] The present invention discloses a bimetallic composite pipe bonding strength testing device and testing method, which include a shear mandrel, an outer cylinder and a power device. Samples can be taken from the actual bimetallic composite pipe product, and multiple samples taken from the same bimetallic composite pipe can be tested simultaneously under the same conditions, so that the reliability and repeatability of the test data can be effectively judged. The outer cylinder is provided with a groove, which can be engaged and fixed with the sample, so the sample is stably clamped, the device is easy to operate, and the test efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0029] Figure 1 This is a schematic diagram of the overall structure of the bimetallic composite pipe bonding strength testing device provided by the present invention;

[0030] Figure 2 A schematic diagram of a circumferential cross section of an outer cylinder of a bimetallic composite pipe bonding strength testing device provided by the present invention;

[0031] Figure 3 A schematic structural diagram of an outer cylinder of a bimetallic composite pipe bonding strength testing device provided by the present invention;

[0032] Figure 4 A schematic diagram of the structure of a group of test specimens of the bimetallic composite pipe bonding strength testing device provided by the present invention when they are assembled into an outer tube;

[0033] Figure 5A schematic cross-sectional view of a composite pipe sample of the bimetallic composite pipe bonding strength testing device provided by the present invention;

[0034] Figure 6 A schematic structural diagram of a group of test specimens of the bimetallic composite pipe bonding strength testing device provided by the present invention.

[0035] Among them: base-10; shear mandrel-20; outer cylinder-30; groove-31; hydraulic cylinder-40; hydraulic system-41; hydraulic gauge-411; composite pipe sample-50; outer layer-51; inner layer-52.

[0036] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0037] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0038] The terms "first", "second", etc. in the specification and claims of the present disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein, for example.

[0039] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0040] Multiple includes two or more.

[0041] It should be understood that the term "and / or" used in this disclosure is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone.

[0042] like Figure 1 to Figure 3As shown, an embodiment of the technical solution of the present invention provides a bimetallic composite pipe bonding strength testing device, including a base 10, on which a shear mandrel 20, an outer cylinder 30 and a power device are provided.

[0043] The outer cylinder 30 is fixed on the base 10. The outer cylinder 30 is used to place the composite pipe sample 50 to be tested. The inner surface of the outer cylinder 30 is provided with a plurality of grooves 31, and the grooves 31 fix the composite pipe sample 50 to be tested. The outer cylinder 30 is coaxially arranged with the shear mandrel 20. The shear mandrel 20 is arranged close to one end of the outer cylinder 30. The power device can drive the shear mandrel 20 to move along the axial direction of the outer cylinder 30 and extend into the interior of the outer cylinder 30. The composite pipe sample 50 to be tested includes an outer layer 51 and an inner layer 52. The shear mandrel 20 can apply a shear force to the inner layer 52.

[0044] The present invention can take samples from the actual product of the composite pipe sample 50, and test multiple samples taken from the same composite pipe at the same time under the same conditions, so as to effectively judge the reliability and repeatability of the test data. In addition, the outer cylinder 30 is provided with a groove 31, which can be engaged and fixed with the composite pipe sample 50, so that the composite pipe sample 50 is stably clamped, the device is easy to operate, and the test efficiency is high.

[0045] In this embodiment, preferably, each groove 31 is evenly distributed along the circumference of the inner surface of the outer cylinder 30. Multiple grooves 31 can fix multiple composite pipe samples 50, and multiple composite pipe samples 50 can be tested in the same test, which has high test efficiency and can provide multiple test data, making the test results more accurate. Preferably, there are 2 to 6 grooves 31, and further, there are 6 grooves 31, and the size of each groove 31 is the same, and the spacing between each groove 31 is the same. Since the size and spacing of each groove 31 are the same, it is convenient to process the composite pipe sample 50 so that the composite pipe sample 50 can be fixed in the outer cylinder 30.

[0046] In the present embodiment, the groove 31 is preferably a dovetail groove, so the bottom area of ​​the figure formed by the groove 31 along the circumferential cross section is larger than the opening area, presenting a trapezoidal shape. Therefore, the composite tube sample 50 will not fall after being fixed to the outer cylinder 30, thereby ensuring that the outer cylinder 30 and the composite tube sample 50 remain stable during the test process, thereby improving the accuracy of the test result.

[0047] Specifically, one end of the outer cylinder 30 is open at one end of the groove 31, and is arranged axially, extending to the other end of the outer cylinder 30 and being blocked, that is, the groove 31 does not penetrate the other end of the outer cylinder 30. The distance between the end of the groove 31 blocked by the outer cylinder 30 and the blocked end of the outer cylinder 30 is greater than 20 mm. Since the groove 31 is a dovetail groove, the composite tube sample 50 is inserted into the outer cylinder 30 through the groove 31 of the outer cylinder 30 for fixing, and the groove 31 is a non-penetrating groove. During the test, the unpenetrated part of the outer cylinder 30 can resist the composite tube sample 50, providing a counterforce to the composite tube sample 50, ensuring the axial stability of the composite tube sample 50, and preventing the composite tube sample 50 from coming out of the outer cylinder 30 due to the force. When fixing, the outer layer 51 of the composite tube sample 50 needs to be processed into a structure that is compatible with the groove 31.

[0048] Furthermore, the shearing mandrel 20 is located at an open end of the groove 31 .

[0049] In this embodiment, the power device includes a hydraulic cylinder 40 and a hydraulic system 41. The hydraulic cylinder 40 is fixedly arranged on the base 10. The hydraulic system 41 is connected to the hydraulic cylinder 40 and is used to drive the shearing mandrel 20 to move. The hydraulic system 41 includes a hydraulic gauge 411, and the hydraulic gauge 411 displays the hydraulic value of the process of driving the shearing mandrel 20. Of course, the present invention can also adopt other power devices to drive the shearing mandrel 20, such as a motor.

[0050] In this embodiment, the outer diameter of the shearing mandrel 20 is preferably 0-0.2 mm smaller than the inner diameter of the outer cylinder 30 , so that the shearing mandrel 20 can move inside the outer cylinder 30 .

[0051] In this embodiment, preferably, a lubricating layer is provided on the inner surface of the outer cylinder 30 and the outer surface of the shearing mandrel 20. The lubricating layer is an oil film layer formed by applying lubricating oil on the inner surface of the outer cylinder 30 and the outer surface of the shearing mandrel 20. The lubricating layer facilitates the shearing mandrel 20 to slide in the outer cylinder 30, and avoids the large friction between the outer cylinder 30 and the shearing mandrel 20 to affect the experimental effect.

[0052] In this embodiment, the shear mandrel 20 is a solid cylindrical structure, or a hollow cylindrical structure with one end sealed and the other end open, and the open end of the shear mandrel 20 faces the outer cylinder 30. Regardless of the structure of the shear mandrel 20, it is necessary to ensure that the wall thickness of the shear mandrel 20 is greater than the thickness of the inner layer 52 of the composite pipe sample 50 to be tested. The inner layer 52 is subjected to uniform force, thereby ensuring the accuracy of the test results.

[0053] In this embodiment, the outer cylinder 30 and the liquid cylinder 40 are welded and fixed on the base 10, wherein the outer cylinder 30 and the liquid cylinder 40 can be coaxially arranged in the horizontal direction or in the vertical direction, which is not limited here.

[0054] In this embodiment, the outer cylinder 30 is made of carbon steel, the inner surface of the outer cylinder 30 is chrome-plated, and the shear mandrel 20 is hard alloy. The outer cylinder 30 has high hardness, high strength, and strong supporting force. At the same time, chromium has strong wear resistance. The chrome plating of the outer cylinder 30 increases the service life. The shear mandrel 20 is hard alloy, which has high strength and avoids deformation and wear during the test process, which affects the test results.

[0055] like Figure 4 and Figure 5 As shown, in this embodiment, the test sample is a section cut from the composite pipe sample 50 to be tested, and is processed into an arc shape, the outer layer 51 is adapted to the groove 31, and the bonding surface of the outer layer 51 and the inner layer 52 is flush with the circumferential opening of the groove 31, so that the shear mandrel 20 can apply a shear force to the inner layer 52 after entering the outer cylinder 30 to test the bonding strength between the inner layer 52 and the outer layer 51. Among them, the outer layer 51 is made of carbon steel and is the load-bearing body of the composite pipe sample 50, and the inner layer 52 is made of corrosion-resistant alloy and is the corrosion-resistant layer of the composite pipe sample 50.

[0056] like Figure 1 to Figure 6 As shown, according to the second aspect of the technical solution of the present invention, a method for testing the bonding strength of the bimetallic composite pipe sample 50 as described above is provided, comprising:

[0057] S1. Select the outer cylinder 30 and the shear mandrel 20 according to the outer diameter and wall thickness of the composite pipe to be tested;

[0058] S2. Cutting a plurality of composite tube samples 50 from the composite tube to be tested according to the cross-sectional size, axial depth and number of the grooves of the outer tube 30;

[0059] S3, setting the axial length of the inner layer 52 of the composite tube sample 50 and the axial spacing of the inner layer 52 between the composite tube samples 50;

[0060] S4, processing the inner layer 52 of the composite tube sample 50 according to the set value;

[0061] S5. Calculate the bonding interface area between the outer layer 51 and the inner layer 52 of the composite tube sample 50;

[0062] S6. According to the positions of the remaining inner layers 52 of the composite tube sample 50, the composite tube sample 50 is fixed in the grooves 31 of the outer tube 30 in sequence at equal intervals;

[0063] S7, start the power device, drive the shearing mandrel 20 to move axially along the outer cylinder 30, shear the inner layer 52 of the composite tube sample 50, and record the data value of the power device during shearing;

[0064] S8. Calculate the bonding strength between the outer layer 51 and the inner layer 52 of the composite tube sample 50 according to the data value of the power device and the bonding interface area between the outer layer 51 and the inner layer 52 of the composite tube sample 50.

[0065] In step S1 , the outer cylinder 30 and the shear mandrel 20 with the most matching sizes are selected according to the outer diameter and the wall thickness of the composite tube sample 50 to be tested, thereby reducing the reprocessing of the composite tube sample 50 .

[0066] In step S2, the processing of the composite tube sample 50 is specifically as follows: the curvature of the outer surface of the composite tube sample 50 is the same as the curvature of the groove 31, the thickness of the outer layer 51 is the same as the depth of the groove 31, the length of the composite tube sample 50 is the same as the axial depth of the groove 31, and the composite tube sample 50 is cut into an arc-shaped cylindrical sample in which the outer layer 51 matches the groove 31.

[0067] In step S3, specifically, the thickness of the inner layer 52 is greater than 1 mm, and the axial length is 4-6 mm, preferably 5 mm. During the test, the axial spacing between the inner layers 52 of two adjacent composite pipe samples 50 is greater than 10 mm, preferably 20 mm.

[0068] In step S4 , a section of the inner layer 52 needs to be retained according to the setting, and the remaining inner layer 52 is removed.

[0069] In step S6, the composite tube sample 50 is placed in the groove 31 in an order according to the position of the remaining inner layer 52. During the experiment, each inner layer 52 portion on the composite tube sample 50 is sheared one by one by the shearing mandrel 20, and multiple composite tube samples 50 can be tested in one test, which is more accurate for the calculation of the bonding strength.

[0070] In step S7, since the distance between the inner layer 52 of each sample and the open end of the outer cylinder 30 is different, the shearing mandrel 20 shears the inner layer 52 of each sample in turn, and records the hydraulic value of the hydraulic gauge 411 when each sample is sheared.

[0071] In step S8 , the bonding strength is calculated as follows: bonding strength=shear force / shear area, wherein the shear force is the hydraulic pressure value*the cross-sectional area of ​​the shear mandrel 20 , and the shear area is the bonding interface area between the outer layer 51 and the inner layer 52 .

[0072] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0073] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0074] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0075] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A bimetallic composite pipe bonding strength testing device, characterized in that: It comprises a base, on which a shearing mandrel, an outer cylinder and a power device are arranged; The outer cylinder is fixed on the base, and the outer cylinder is used to place the composite pipe sample to be tested. The inner surface of the outer cylinder is provided with a plurality of grooves, and the grooves fix the composite pipe sample to be tested; The outer cylinder is coaxially arranged with the shearing mandrel, the shearing mandrel is arranged close to one end of the outer cylinder, and the power device can drive the shearing mandrel to move along the axial direction of the outer cylinder and extend into the interior of the outer cylinder; The composite pipe sample comprises an inner layer and an outer layer, and the shear mandrel can apply a shear force to the inner layer of the composite pipe sample.

2. The bimetallic composite pipe bonding strength testing device according to claim 1, characterized in that: The grooves are evenly distributed along the circumference of the inner surface of the outer cylinder.

3. The bimetallic composite pipe bonding strength testing device according to claim 1, characterized in that: The groove is a dovetail groove.

4. The bimetallic composite pipe bonding strength testing device according to claim 1, characterized in that: The groove opens from one end of the outer tube, is arranged along the axial direction, and extends to the other end of the outer tube and is blocked.

5. The bimetallic composite pipe bonding strength testing device according to claim 4, characterized in that: The distance between the end of the groove at one end blocked by the outer tube and the blocked end of the outer tube is greater than 20 mm.

6. The bimetallic composite pipe bonding strength testing device according to claim 1, characterized in that: The power device comprises a hydraulic cylinder and a hydraulic system. The hydraulic cylinder is fixedly arranged on the base. The hydraulic system is connected to the hydraulic cylinder and is used to drive the shearing spindle to move.

7. The bimetallic composite pipe bonding strength testing device according to claim 1, characterized in that: The outer diameter of the shear mandrel is 0 to 0.2 mm smaller than the inner diameter of the outer cylinder.

8. The bimetallic composite pipe bonding strength testing device according to claim 1, characterized in that: A lubricating layer is provided on the inner surface of the outer cylinder and the outer surface of the shear mandrel.

9. A method for testing the bonding strength of a bimetallic composite pipe according to any one of claims 1 to 8, characterized in that: include: S1. Select the outer cylinder and shear mandrel according to the outer diameter and wall thickness of the composite tube to be tested; S2. Cutting a plurality of composite tube samples from the composite tube to be tested according to the cross-sectional size, axial depth and number of the grooves of the outer tube; S3, setting the axial length of the inner layer of the composite tube sample and the axial spacing of the inner layers between the composite tube samples; S4, processing the inner layer of the composite tube sample according to the set value; S5. Calculate the bonding interface area between the outer layer and the inner layer of the composite tube sample; S6. Fix the composite tube samples in the grooves of the outer tube in sequence at equal intervals according to the positions of the remaining inner layers of the composite tube samples; S7, starting the power device to drive the shearing mandrel to move axially along the outer cylinder to shear the inner layer of the composite tube sample, and recording the data value of the power device during shearing; S8. Calculate the bonding strength between the outer layer and the inner layer of the composite tube sample according to the data value of the power device and the bonding interface area between the outer layer and the inner layer of the composite tube sample.

10. The testing method of the bimetallic composite pipe bonding strength testing device according to claim 9, characterized in that: The composite tube sample in step S2 is an arc-shaped columnar structure.

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