Wide Plate Tensile Testing Method and Wide Plate Tensile Testing Apparatus

Abstract

This invention provides a method and apparatus for testing the tensile strength of a wide plate. The method includes: acquiring a wide plate tensile testing apparatus and a wide plate tensile specimen; obtaining the basic standard force of the wide plate tensile specimen; applying tension to the wide plate tensile specimen using the wide plate tensile testing apparatus; and recording the moment when the ratio between the real-time tensile force and the basic standard force reaches a preset value as the first time point, while simultaneously recording the slope of the real-time relationship curve between the real-time tensile force and displacement of the wide plate tensile testing apparatus as K. i Simultaneously, a pre-braking step is initiated: the slope of the real-time tensile force versus displacement curve of the wide plate tensile test specimen at the second time point is obtained as K. i+1 According to K i+1 The tensile force applied to the wide plate tensile testing device is adjusted. This invention solves the problem of difficulty in determining the timing of the end of the wide plate tensile test in the prior art.

Description

Technical Field

[0001] This invention relates to the field of petroleum equipment technology, and more specifically, to a method and apparatus for testing the tensile strength of a wide plate. Background Technology

[0002] With the increasing pressure requirements for oil and gas transportation, pipeline steel is developing towards higher strength, and the stress conditions on the pipeline base material and welds are becoming increasingly demanding. Special performance tests for oil and gas transmission pipelines are test methods used to evaluate the performance and reliability of pipelines under special operating conditions. One common special performance test is the wide plate tensile test, which is used to evaluate the material strength and ductility of the pipeline.

[0003] In wide-plate tensile testing, a large-width plate sample is placed on a tensile testing machine and stretched by applying a vertical tensile force. This testing method is very useful for evaluating the mechanical properties of pipe materials in various directions, including tensile strength, yield strength, breaking strength, and elongation. These performance parameters are important indicators for evaluating the reliability and service life of pipe materials. In wide-plate tensile testing, the sample is typically stretched along the axial and transverse directions of the pipe to simulate the stress conditions under actual use. During the test, the loading force and the deformation of the sample are recorded to determine the strength and ductility of the material. By comparing the dimensional changes and stress-strain curves of the sample before and after stretching, the reliability and performance of the pipe material can be evaluated. In current tests, one of the criteria for determining the end of the test is "the load begins to decrease and reaches 95% of the maximum load." Existing wide-plate tensile testing machines have a short time for the load to decrease from the maximum to 95%. The testing machine adjusts the hydraulic system load force in real time according to the changes in the load curve during the test, causing the test to continue to apply pressure after the load begins to decrease and reaches 95% of the maximum load, ultimately leading to sample fracture. The fracture of the sample can damage precision instruments mounted on the sample, including displacement sensors and COD (Catalyst, Analyzer, and Displacement Device). Clearly, the current method of determining the end of the test is unacceptable, as it not only damages the sample but also harms surrounding devices.

[0004] In other words, existing wide plate tensile testing technologies suffer from difficulties in determining the termination time. Summary of the Invention

[0005] The main objective of this invention is to provide a method and apparatus for testing wide plates tensile strength, in order to solve the problem of difficulty in determining the timing of the end of wide plate tensile tests in the prior art.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for testing the tensile strength of a wide plate is provided, comprising the following steps: an initial data acquisition step: acquiring a wide plate tensile testing device and a wide plate tensile specimen, and calculating the basic standard force of the wide plate tensile specimen; a tensile step: using the wide plate tensile testing device to tensile the wide plate tensile specimen, wherein the tensile force exerted by the wide plate tensile testing device on the wide plate tensile specimen increases with time; when the ratio between the real-time tensile force exerted by the wide plate tensile testing device on the wide plate tensile specimen and the basic standard force reaches a preset value, this point is recorded as the first time point, and the slope of the real-time relationship curve between the real-time tensile force and displacement of the wide plate tensile testing device on the wide plate tensile specimen at the first time point is recorded as K. i Simultaneously, a pre-braking step is initiated; the pre-braking step involves obtaining the slope of the real-time tensile force versus displacement curve of the wide plate tensile test specimen at the second time point using the wide plate tensile testing device, which is K. i+1 According to K i+1 Adjust the magnitude of the tensile force applied to the wide plate tensile test specimen by the wide plate tensile testing device.

[0007] Furthermore, the wide plate tensile testing method also includes a termination step following the pre-braking step, which includes stopping the tensile test when the ratio between the real-time tensile force of the wide plate tensile test device on the wide plate tensile specimen and the basic standard force reaches 95%.

[0008] Furthermore, in the stretching step, the preset value is 60%.

[0009] Furthermore, in the pre-braking step, when K i+1 >K i At the same time, the tensile force applied to the wide plate tensile test specimen by the wide plate tensile test device is kept twice the basic standard force.

[0010] Furthermore, in the pre-braking step, the slope of the real-time tensile force versus displacement curve of the wide plate tensile test specimen obtained at the third time point is K. i+2 When K i+1 >K i And K i+2 <K i+1 At the same time, the tensile force of the wide plate tensile testing device on the wide plate tensile specimen is kept at 1.5 times the basic standard force.

[0011] Furthermore, in the pre-braking step, the slope of the real-time tensile force versus displacement curve of the wide plate tensile test specimen at time point n is obtained as K. i+n When K i+n When = 0, the tensile force of the wide plate tensile test device on the wide plate tensile specimen remains unchanged.

[0012] Furthermore, in the pre-braking step, the magnitude of the tensile force exerted by the wide plate tensile testing device on the wide plate tensile specimen is adjusted by adjusting the size of the flow valve of the hydraulic cylinder of the wide plate tensile testing device.

[0013] According to another aspect of the present invention, a wide plate tensile testing device is provided, which implements the above-described wide plate tensile testing method. The wide plate tensile testing device includes: a frame having an accommodating space; a first mounting clamp disposed in the accommodating space, and one side of the first mounting clamp being connected to the frame via a fixing cylinder; and a second mounting clamp disposed in the accommodating space and located on the other side of the first mounting clamp, wherein the distance between the second mounting clamp and the first mounting clamp is adjustable via a hydraulic cylinder, and a tensile station for assembling a wide plate tensile specimen is formed between the first mounting clamp and the second mounting clamp.

[0014] Furthermore, the wide plate tensile testing device also includes a hydraulic rod, and the hydraulic cylinder is driven to the second mounting clamp via the hydraulic rod.

[0015] Furthermore, the frame has a set of frames arranged opposite to each other, the fixed cylinder passes through one of the frames, the hydraulic rod passes through the other of the frames, and the fixed cylinder and the hydraulic rod are respectively connected to a first mounting bracket and a second mounting bracket at their opposite ends, and / or the line connecting the first mounting bracket and the second mounting bracket coincides with the extension line of the movement trajectory of the second mounting bracket.

[0016] The wide plate tensile testing method according to the technical solution of this invention includes the following steps: Initial data acquisition step: acquiring a wide plate tensile testing device and a wide plate tensile specimen, and calculating the basic standard force of the wide plate tensile specimen; Tensile step: using the wide plate tensile testing device to stretch the wide plate tensile specimen. The tensile force exerted by the wide plate tensile testing device on the wide plate tensile specimen increases with time. When the ratio between the real-time tensile force exerted by the wide plate tensile testing device on the wide plate tensile specimen and the basic standard force reaches a preset value, this point is recorded as the first time point. Simultaneously, the slope of the real-time relationship curve between the real-time tensile force and displacement of the wide plate tensile testing device on the wide plate tensile specimen at the first time point is recorded as K. i Simultaneously, a pre-braking step is initiated; the pre-braking step involves obtaining the slope of the real-time tensile force versus displacement curve of the wide plate tensile test specimen at the second time point using the wide plate tensile testing device, which is K. i+1 According to K i+1 Adjust the magnitude of the tensile force applied to the wide plate tensile test specimen by the wide plate tensile testing device.

[0017] This application, through a pre-braking step, uses a wide-plate tensile testing device at the next time point to obtain a real-time curve showing the slope of the real-time tensile force versus displacement relationship of the wide-plate tensile specimen, which is K. i+1By predicting the slope's decreasing trend and controlling the tensile force when the slope begins to decrease, the tensile force applied to the wide plate tensile test specimen by the testing device can be adjusted. This allows for a more accurate determination of when to terminate the wide plate tensile test, ensuring termination only when the tensile force approaches its maximum value. This increases the accuracy and repeatability of the test, while also improving testing precision and further protecting the wide plate tensile specimen and surrounding instruments. The pre-braking step effectively prevents the wide plate tensile specimen from breaking and damaging precision instruments such as displacement sensors and COD gauges. This helps extend the lifespan of instruments and equipment, reducing maintenance and replacement costs. Furthermore, it improves work efficiency; the automated test termination criteria reduce the need for manual intervention, making the testing system more efficient and automated, thus saving time and human resources and improving work efficiency. This contributes to enhancing the reliability and efficiency of special performance testing for oil and gas pipelines. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 A flowchart of a wide plate tensile testing method according to an optional embodiment of the present invention is shown;

[0020] Figure 2 A schematic diagram of the structure of a wide plate tensile testing device according to an optional embodiment of the present invention is shown;

[0021] Figure 3 The real-time tensile force versus displacement curve of a wide plate tensile testing method according to an optional embodiment of the present invention is shown.

[0022] The above figures include the following reference numerals:

[0023] 10. Frame; 20. First mounting clamp; 30. Second mounting clamp; 40. Fixed cylinder; 51. Hydraulic rod; 52. Hydraulic cylinder; 60. Wide plate tensile specimen. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0026] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0027] To address the difficulty in determining the end time in existing wide-plate tensile testing techniques, this invention provides a wide-plate tensile testing method and a wide-plate tensile testing apparatus.

[0028] like Figures 1 to 3 As shown, the wide plate tensile testing method includes the following steps: Initial data acquisition step: Acquire the wide plate tensile testing device and the wide plate tensile specimen 60, and calculate the basic standard force of the wide plate tensile specimen 60; Tensile step: Use the wide plate tensile testing device to stretch the wide plate tensile specimen 60. The tensile force exerted by the wide plate tensile testing device on the wide plate tensile specimen 60 increases with time. When the ratio between the real-time tensile force exerted by the wide plate tensile testing device on the wide plate tensile specimen 60 and the basic standard force reaches a preset value, this point is recorded as the first time point. Simultaneously, the slope of the real-time relationship curve between the real-time tensile force and displacement of the wide plate tensile testing device on the wide plate tensile specimen 60 at the first time point is recorded as K. i Simultaneously, a pre-braking step is initiated; the pre-braking step involves obtaining the slope of the real-time tensile force versus displacement curve of the wide plate tensile test specimen 60 at the second time point using the wide plate tensile testing device, which is K. i+1 According to K i+1 Adjust the tensile force applied to the wide plate tensile test specimen 60 by the wide plate tensile test device.

[0029] This application, through a pre-braking step, uses a wide-plate tensile testing device at the next time point to obtain a real-time curve showing the real-time tensile force versus displacement relationship of the wide-plate tensile specimen 60, with the slope being K. i+1By predicting the slope's decreasing trend and controlling the tensile force when the slope begins to decrease, the tensile force applied to the wide plate tensile test specimen 60 by the wide plate tensile testing device can be adjusted. This allows for a more accurate determination of the termination time of the wide plate tensile testing method, ensuring termination only when the tensile force approaches its maximum value. This increases the accuracy and repeatability of the test, while also improving testing precision and further protecting the wide plate tensile specimen 60 and surrounding instruments. The pre-braking step effectively prevents the wide plate tensile specimen 60 from breaking and damaging the precision instruments used, such as displacement sensors and COD gauges. This helps extend the service life of instruments and equipment, reducing maintenance and replacement costs. Furthermore, it improves work efficiency; the automated test termination criteria reduce the need for manual intervention, making the testing system more efficient and automated, thus saving time and human resources, and improving work efficiency. This contributes to improving the reliability and efficiency of special performance testing of oil and gas pipelines.

[0030] It should be noted that the basic standard force of the above-mentioned wide plate tensile specimen 60 is related to the actual material of the wide plate tensile specimen 60, and the basic standard force of the wide plate tensile specimen 60 is different for different materials.

[0031] Specifically, the wide-plate tensile testing method also includes a termination step following the pre-braking step. This termination step involves stopping the tensile test when the ratio between the real-time tensile force exerted by the wide-plate tensile testing device on the wide-plate tensile specimen 60 and the basic standard force reaches 95%. Since the real-time tensile force exerted by the wide-plate tensile testing device on the wide-plate tensile specimen 60 increases over time, determining the timing of the test termination through the pre-braking step ensures that the test terminates after the tensile force reaches 95% of its maximum value. This improves test accuracy and prevents further increases in tensile force that could lead to tearing of the wide-plate tensile specimen 60.

[0032] Specifically, in the tensile step, the preset value is 60%. That is, when the ratio between the real-time tensile force of the wide plate tensile test device on the wide plate tensile specimen 60 and the basic standard force reaches 60%, the pre-braking step is initiated.

[0033] In the pre-braking step, the magnitude of the tensile force of the wide plate tensile test device on the wide plate tensile specimen 60 is adjusted by adjusting the size of the flow valve port of the hydraulic cylinder 52 of the wide plate tensile test device.

[0034] Specifically, in the pre-braking step, when K i+1 >K i At the same time, by adjusting the flow valve of the hydraulic cylinder 52 of the wide plate tensile testing device to keep it unchanged, the tensile force of the wide plate tensile testing device on the wide plate tensile specimen 60 is kept twice the basic standard force.

[0035] Then, the slope of the real-time tensile force versus displacement curve of the wide plate tensile test device at the third time point is obtained as K. i+2 When K i+1 >K i Under the premise that K i+2 <K i+1 At this time, by adjusting the flow valve of the hydraulic cylinder 52 of the wide plate tensile testing device to reduce the flow rate, the tensile force of the wide plate tensile testing device on the wide plate tensile specimen 60 is maintained at 1.5 times the basic standard force.

[0036] Then, based on the above method, the slopes of the real-time tensile force versus displacement curves at three additional time points are obtained. The slopes at the three time points are compared according to the above method, thereby adjusting the tensile force of the wide plate tensile testing device on the wide plate tensile specimen 60.

[0037] Furthermore, in the pre-braking step, the slope of the real-time tensile force versus displacement curve of the wide plate tensile test device at time point n for the wide plate tensile specimen 60 is obtained as K. i+n When K i+n When the value is 0, the current situation is maintained by adjusting the flow valve of the hydraulic cylinder 52 of the wide plate tensile testing device, so as to maintain the tensile force of the wide plate tensile testing device on the wide plate tensile specimen 60 at this time.

[0038] This setup allows the flow valve of hydraulic cylinder 52 to be adjusted simultaneously to reduce the tensile force of hydraulic cylinder 52 as the slope begins to decrease, stopping the tension once 95% of the maximum load is reached, thus terminating the test. This allows for precise judgment of when to end the test, avoiding the risk of excessive tensile force causing tearing of the wide plate tensile specimen 60 and damage to surrounding instruments, ensuring test accuracy, and saving costs.

[0039] refer to Figure 3 , Figure 3 The real-time relationship curve between the tensile force P (kN) and displacement L (mm) of the wide plate tensile test specimen 60 under the wide plate tensile testing device is shown. This curve is a two-dimensional curve. The intersection of the curve and the horizontal dashed line in the figure represents the real-time relationship curve between the tensile force P and displacement of the wide plate tensile test specimen 60 under the wide plate tensile testing device at the first time point, with a slope of K. i .

[0040] like Figure 2As shown, the present invention also provides a wide plate tensile testing device, which implements the above-mentioned wide plate tensile testing method. The wide plate tensile testing device includes a frame 10, a first mounting clamp 20, and a second mounting clamp 30. The frame 10 has an accommodating space. The first mounting clamp 20 is disposed in the accommodating space, and one side of the first mounting clamp 20 is connected to the frame 10 through a fixing cylinder 40. The second mounting clamp 30 is disposed in the accommodating space and located on the other side of the first mounting clamp 20. The distance between the second mounting clamp 30 and the first mounting clamp 20 is adjustable through a hydraulic cylinder 52. A tensile station for assembling a wide plate tensile specimen 60 is formed between the first mounting clamp 20 and the second mounting clamp 30. The clamping ends of the first mounting clamp 20 and the second mounting clamp 30 are arranged opposite to each other, so that the first mounting clamp 20 and the second mounting clamp 30 can respectively clamp both sides of the wide plate tensile specimen 60.

[0041] like Figure 2 As shown, the wide plate tensile testing device also includes a hydraulic rod 51, and a hydraulic cylinder 52 is drivenly connected to the second mounting clamp 30 via the hydraulic rod 51. The frame 10 has a set of opposing frame sections. A fixed cylinder 40 passes through one of the frame sections and extends into the accommodating space. One end of the fixed cylinder 40 extending into the accommodating space is connected to the first mounting clamp 20. The hydraulic rod 51 passes through the other frame section. One end of the hydraulic rod 51 extends into the accommodating space and is bolted to the second mounting clamp 30. The other end of the hydraulic rod 51 is outside the frame 10 and connected to the hydraulic cylinder 52. The fixed cylinder 40 and the hydraulic rod 51 are respectively connected to the first mounting clamp 20 and the second mounting clamp 30 at their respective facing ends. The line connecting the first mounting clamp 20 and the second mounting clamp 30 coincides with the extension line of the movement trajectory of the second mounting clamp 30, meaning that the second mounting clamp 30 moves left and right.

[0042] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0043] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0044] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for tensile testing of wide plates, characterized in that, Includes the following steps: Initial data acquisition steps: acquire the wide plate tensile testing device and the wide plate tensile specimen (60), and calculate the basic standard force of the wide plate tensile specimen (60); Tensile Step: The wide plate tensile testing device is used to stretch the wide plate tensile specimen (60). The tensile force of the wide plate tensile testing device on the wide plate tensile specimen (60) increases with time. When the ratio between the real-time tensile force of the wide plate tensile testing device on the wide plate tensile specimen (60) and the basic standard force reaches a preset value, this time is recorded as the first time point. At the same time, the slope of the real-time relationship curve between the real-time tensile force and displacement of the wide plate tensile testing device on the wide plate tensile specimen (60) at the first time point is recorded as K. i At the same time, the pre-braking procedure is initiated; The pre-braking step involves obtaining the slope of the real-time tensile force versus displacement curve of the wide plate tensile test device on the wide plate tensile specimen (60) at the second time point, which is K. i+1 According to K i+1 Adjust the magnitude of the tensile force exerted by the wide plate tensile testing device on the wide plate tensile specimen (60); In the pre-braking step, when K i+1 >K i At the same time, the tensile force exerted by the wide plate tensile testing device on the wide plate tensile specimen (60) is kept at twice the basic standard force; In the pre-braking step, the slope of the real-time tensile force versus displacement curve of the wide plate tensile test device at the third time point is K. i+2 When K i+1 >K i And K i+2 <K i+1 At the same time, the tensile force exerted by the wide plate tensile testing device on the wide plate tensile specimen (60) is maintained at 1.5 times the basic standard force; in the pre-braking step, the slope of the real-time relationship curve between the real-time tensile force and displacement of the wide plate tensile testing device on the wide plate tensile specimen (60) at the nth time point is K. i+n When K i+n When =0, the tensile force of the wide plate tensile testing device on the wide plate tensile specimen (60) remains unchanged; The wide plate tensile testing method further includes a termination step following the pre-braking step, wherein the termination step includes stopping the stretching when the ratio between the real-time tensile force of the wide plate tensile test device on the wide plate tensile specimen (60) and the basic standard force reaches 95%.

2. The wide plate tensile testing method according to claim 1, characterized in that, In the stretching step, the preset value is 60%.

3. The method for tensile testing of wide plates according to any one of claims 1 to 2, characterized in that, In the pre-braking step, the magnitude of the tensile force exerted by the wide plate tensile testing device on the wide plate tensile specimen (60) is adjusted by adjusting the size of the flow valve of the hydraulic cylinder (52) of the wide plate tensile testing device.

4. A wide plate tensile testing device, characterized in that, The wide plate tensile testing device described above is used to implement the wide plate tensile testing method according to any one of claims 1 to 3, wherein the wide plate tensile testing device comprises: A frame (10) having an accommodating space; The first mounting bracket (20) is disposed in the accommodating space, and one side of the first mounting bracket (20) is connected to the frame (10) through a fixing cylinder (40); The second mounting clamp (30) is disposed in the accommodating space and located on the other side of the first mounting clamp (20). The distance between the second mounting clamp (30) and the first mounting clamp (20) is adjustable by means of a hydraulic cylinder (52). A tensile station for assembling a wide plate tensile specimen (60) is formed between the first mounting clamp (20) and the second mounting clamp (30).

5. The wide plate tensile testing device according to claim 4, characterized in that, The wide plate tensile testing device also includes a hydraulic rod (51), and the hydraulic cylinder (52) is driven to the second mounting bracket (30) through the hydraulic rod (51).

6. The wide plate tensile testing device according to claim 5, characterized in that, The frame (10) has a set of frame portions arranged opposite to each other. The fixed cylinder (40) passes through one of the set of frame portions, and the hydraulic rod (51) passes through the other of the set of frame portions. The fixed cylinder (40) and the hydraulic rod (51) are respectively connected to the first mounting bracket (20) and the second mounting bracket (30) at their respective ends facing each other, and / or the line connecting the first mounting bracket (20) and the second mounting bracket (30) coincides with the extension line of the movement trajectory of the second mounting bracket (30).

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