A high-temperature high-pressure tensile testing machine and a testing method

Abstract

This application relates to the field of material performance testing technology, and in particular to a high-temperature and high-pressure tensile testing machine and testing method. The tensile testing machine includes a frame assembly, a high-temperature and high-pressure autoclave, an electromagnetic induction heating coil, a force-balanced autoclave, a tensile loading system, a hydraulic control system, and a high-temperature resistant force sensor. This application establishes a high-temperature and high-pressure testing chamber and a force-balanced high-pressure chamber by setting up an independent force-balanced autoclave. By controlling the hydraulic control system to inject a second pressurizing medium into the force-balanced high-pressure chamber, real-time dynamic balancing of the axial force generated during the tensile process of the specimen under high-temperature and high-pressure conditions is achieved. This effectively counteracts the initial axial force generated by the high-pressure medium acting on the end face of the tensile rod, and more actively responds to the dynamic additional axial force mutation caused by specimen yielding and necking, thereby improving the reliability of the test results. Simultaneously, fixing the high-temperature resistant force sensor to the side of the fixed rod avoids the frictional resistance generated between the sealing rings under conventional settings, further improving the reliability of the test results.

Description

Technical Field

[0001] This application relates to the field of material performance testing technology, and in particular to a high-temperature and high-pressure tensile testing machine and testing method. Background Technology

[0002] Currently, the intensity of oil and gas exploration and development in China continues to increase, especially the development of deep wells, ultra-deep wells, and high-temperature, high-pressure, and high-yield wells. This has led to a growing demand for material mechanical property testing of various downhole tools, with testing standards gradually rising. Therefore, it is necessary to have comprehensive testing methods to reduce the risk of accidents during on-site construction through preliminary laboratory testing.

[0003] However, current indoor testing methods have the following problems: When conducting mechanical property tests on metallic materials inside a high-temperature, high-pressure autoclave, the high pressure inside the autoclave generates an initial axial force on the end face of the tension rod. During the tensile process, the sample undergoes yielding and necking, leading to a decrease in cross-sectional area, which gradually increases the axial force generated by the high pressure inside the autoclave. This axial force generated by necking is called the additional axial force. In other words, this additional axial force pushes the tension rod, causing the force sensor to measure an inflated force. Existing solutions are mostly static balancing systems, which can only counteract the initial axial force generated when the cross-sectional area of ​​the sample does not change significantly during the elastic phase. However, this method can only output a fixed axial force based on preset parameters such as the cross-sectional area, resulting in a large error, and it does not address the additional axial force. Furthermore, due to the harsh environment of high temperature and high pressure inside the autoclave, force sensors are usually installed outside the autoclave for indirect measurement of experimental data. The frictional resistance generated between the sealing rings of the tension rod also makes the measurement values ​​of the external force sensor installed on one side of the tension rod unreliable, seriously affecting the experimental data and results.

[0004] Therefore, there is an urgent need for a testing machine that can effectively adjust the additional axial force during high-temperature and high-pressure experiments, so as to obtain more reliable test results. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, this application provides a high-temperature and high-pressure tensile testing machine and testing method, the main purpose of which is to solve the problem that the axial force in the current high-temperature and high-pressure autoclave cannot be accurately balanced, resulting in unreliable test results.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the main technical solutions adopted in this application include:

[0009] On one hand, this application provides a high-temperature and high-pressure tensile testing machine, including: a frame assembly 1, a high-temperature and high-pressure autoclave 2 disposed on the frame assembly 1, an electromagnetic induction heating coil 7 for heating the high-temperature and high-pressure autoclave 2, and further including a force-balancing autoclave 3, a tensile loading system 4, a hydraulic control system 5, and a high-temperature resistant force sensor 6.

[0010] The force-balanced high-pressure vessel 3 is mounted on the frame assembly 1, and the force-balanced high-pressure vessel 3 is located on one side of the high-temperature high-pressure vessel 2 and is coaxially arranged.

[0011] The tensile loading system 4 includes a fixed rod 401 and a tensile rod 402. The tensile rod 402 passes through the force balance autoclave 3 and the high temperature autoclave 2 and can clamp the first end of the sample 9. The fixed rod 401 clamps the second end of the sample 9.

[0012] The end face of the fixed rod 401, the end face of the tension rod 402, and the inner wall of the high-temperature and high-pressure reactor 2 form a high-temperature and high-pressure test chamber A. The tension rod 402 is provided with a ring-shaped force balancing structure. The distal end face of the ring-shaped force balancing structure, the outer wall of the tension rod 402, and the inner wall of the force balancing high-pressure reactor 3 form a force balancing high-pressure chamber B.

[0013] The hydraulic control system 5 is used to inject a first pressurizing medium into the high temperature and high pressure test chamber A and a second pressurizing medium into the force balance high pressure chamber B. The second pressurizing medium is used to balance the axial force generated in the high temperature and high pressure test chamber A. The axial force includes an initial axial force and an additional axial force.

[0014] The high-temperature resistant force sensor 6 is connected to the fixed rod 401 and is used to measure the tensile force applied to the sample 9.

[0015] Optionally, the side wall of the high-temperature and high-pressure reactor 2 is provided with a first pressure inlet 203 for injecting the first pressurizing medium into the high-temperature and high-pressure test chamber A and a second pressure inlet 204 for discharging the first pressurizing medium; the side wall of the force-balanced high-pressure reactor 3 is provided with a third pressure inlet 303 for injecting the second pressurizing medium into the force-balanced high-pressure chamber.

[0016] Optionally, the annular force balance structure is provided with a mounting groove recessed in the circumference, and a sealing element is provided in the mounting groove to isolate the high temperature and high pressure test chamber from the force balance high pressure chamber.

[0017] Optionally, the effective cross-sectional area S of the annular force balance structure satisfies the following relationship:

[0018] S=π×(R 2 -r 2 )

[0019] In the formula, R is the radius of the tension rod 402, and r is the radius of the gauge length segment of the specimen 9.

[0020] Optionally, the outer side of the high-temperature and high-pressure reactor 2 is wrapped with a heat insulation layer 8, and the electromagnetic induction heating coil 7 is wound around the heat insulation layer 8.

[0021] On the other hand, this application provides a testing method using a high-temperature, high-pressure tensile testing machine as described in any of the preceding claims, the method comprising:

[0022] After the sample 9 is filled in response to the user's instructions, the electromagnetic induction heating coil 7 is controlled to heat the high-temperature and high-pressure autoclave 2 to the target temperature.

[0023] With the help of the hydraulic control system 5, a first pressurizing medium is injected into the high temperature and high pressure test chamber A to make the pressure of the high temperature and high pressure test chamber A reach the target pressure. Then, a second pressurizing medium is injected into the force balancing high pressure chamber B to balance the initial axial force generated by the high temperature and high pressure of the high temperature and high pressure test chamber A at the target temperature and the target pressure.

[0024] During the tensile test of the specimen 9 using the tensile loading system 4, the real-time value of the tensile force measured by the high-temperature force sensor 6 is obtained.

[0025] Based on the real-time change in the tensile force, a second pressurized medium is injected into the force-balancing high-pressure chamber B by means of the hydraulic control system 5 to balance the additional axial force generated by the necking phenomenon.

[0026] Optionally, based on the change in the real-time value of the tensile force, a second pressurized medium for balancing the additional axial force generated by the necking phenomenon is injected into the force balance high-pressure chamber B by means of the hydraulic control system 5, including: calculating the difference between the real-time value of the tensile force at the current moment and the real-time value of the tensile force at the previous moment; if the absolute value of the difference is detected to be greater than a preset deviation threshold, it is determined that a necking phenomenon has occurred, and the hydraulic control system 5 is controlled according to the difference.

[0027] Optionally, if the absolute value of the detected difference is greater than a preset deviation threshold, a necking phenomenon is determined to have occurred, and the hydraulic control system 5 is controlled according to the difference, including: based on the real-time value of the tensile force F at the current moment. s The real-time value of the tensile force F at the previous moment m The difference e is calculated; if the absolute value of the difference e is detected to be greater than a preset deviation threshold, the hydraulic control system 5 is controlled to inject the second pressurizing medium into the force balance high-pressure chamber B until the pressure of the force balance high-pressure chamber B is adjusted to P. b Among them, P b=P0+e / S, where P0 is the pressure of the high-pressure chamber B before adjustment, and S is the effective cross-sectional area of ​​the annular force balancing structure.

[0028] Optionally, after injecting a first pressurizing medium into the high-temperature and high-pressure test chamber A using the hydraulic control system 5 to bring the pressure of the high-temperature and high-pressure test chamber A to the target pressure, injecting a second pressurizing medium into the force-balancing high-pressure chamber B to balance the initial axial force generated by the high-temperature and high-pressure test chamber A at the target temperature and the target pressure, includes: controlling the hydraulic control system 5 to inject the first pressurizing medium into the high-temperature and high-pressure test chamber A to bring the pressure of the high-temperature and high-pressure test chamber A to the target pressure P; controlling the hydraulic control system 5 to inject the second pressurizing medium into the force-balancing high-pressure chamber B to bring the pressure of the force-balancing high-pressure chamber B to the target pressure P0; wherein, the force generated by the force-balancing high-pressure chamber B at pressure P0 is used to balance the initial axial force generated by the high-temperature and high-pressure test chamber A at the target temperature and the target pressure P.

[0029] Optionally, after injecting a second pressurizing medium into the force-balancing high-pressure chamber B to balance the additional axial force generated by the necking phenomenon according to the real-time change of the tensile force value, the method further includes: performing a tensile test on the specimen 9 based on the tensile loading system 4 in response to the user's test command until the specimen 9 breaks, generating test data; and depressurizing and cleaning the high-temperature high-pressure test chamber A and the force-balancing high-pressure chamber B in response to the user's cleaning command.

[0030] (III) Beneficial Effects

[0031] The beneficial effects of this application are:

[0032] This application discloses a high-temperature and high-pressure tensile testing machine and method. By setting up an independent force-balancing autoclave, a high-temperature and high-pressure testing chamber and a force-balancing high-pressure chamber are formed. By controlling the hydraulic control system to inject a second pressurizing medium into the force-balancing high-pressure chamber, real-time dynamic balancing of the axial force generated during the tensile process of the specimen under high-temperature and high-pressure conditions is achieved. This effectively counteracts the initial axial force generated by the high-pressure medium acting on the end face of the tensile rod, and more actively responds to the dynamic additional axial force mutation caused by specimen yielding and necking, thereby improving the reliability of the test results. Simultaneously, fixing the high-temperature resistant force sensor to the side of the fixed rod avoids the frictional resistance generated between the sealing rings under conventional settings, further improving the reliability of the test results. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall three-dimensional structure of a high-temperature and high-pressure tensile testing machine according to this application;

[0034] Figure 2This is a side sectional view of a high-temperature and high-pressure tensile testing machine according to this application;

[0035] Figure 3 This is a structural schematic diagram of the tensile loading system of a high-temperature and high-pressure tensile testing machine according to this application;

[0036] Figure 4 This is a schematic diagram of the moving guide rail slider mechanism of a high-temperature and high-pressure tensile testing machine according to this application;

[0037] Figure 5 This is a schematic flowchart of a testing method for a high-temperature and high-pressure tensile testing machine according to this application.

[0038] [Explanation of Labels in the Attached Image]

[0039] 1: Frame assembly; 101: Bench; 102: Control panel; 103: Fixed crossbeam end; 104: Removable insert plate; 105: Support crossbeam end; 106: First support leg; 107: Second support leg; 108: Third support leg; 109: Fourth support leg; 2: High-temperature and high-pressure autoclave; 201: High-temperature and high-pressure autoclave body; 202: High-temperature and high-pressure autoclave cover; 203: First pressure inlet; 204: Second pressure inlet; 3: Force-balanced autoclave; 301: Force-balanced autoclave body; 302: Force-balanced autoclave cover; 303: Third pressure inlet; 4: Tensile loading system; 40 1: Fixed rod; 402: Tension rod; 403: Moving loading beam; 404: Ball screw; 405: Moving guide rail; 406: First slider; 407: Second slider; 408: Guide rail connecting block; 409: Ball nut; 410: Tapered roller bearing; 411: Synchronous pulley; 412: Synchronous belt; 413: Coupling; 414: Servo motor; 5: Hydraulic control system; 501: First pressure head; 502: Second pressure head; 503: Third pressure head; 6: High-temperature force sensor; 7: Electromagnetic induction heating coil; 8: Insulation layer; 9: Sample. Detailed Implementation

[0040] To better understand the above technical solutions, exemplary embodiments of this application will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application can be understood more clearly and thoroughly, and that the scope of this application can be fully conveyed to those skilled in the art.

[0041] like Figure 1The diagram illustrates a high-temperature, high-pressure tensile testing machine (hereinafter referred to as the tensile testing machine) according to this embodiment, including a frame assembly 1, a high-temperature, high-pressure autoclave 2 mounted on the frame assembly 1, and an electromagnetic induction heating coil 7 for heating the high-temperature, high-pressure autoclave 2. It also includes a force-balancing autoclave 3, a tensile loading system 4, and a hydraulic control system 5.

[0042] Combination Figure 2 The side sectional view of the tensile testing machine shown also includes a high-temperature resistant force sensor 6, which is connected to a fixed rod 401 and is used to measure the tensile force applied to the specimen 9.

[0043] The force-balanced high-pressure reactor 3 is mounted on the frame assembly 1, and is located on one side of the high-temperature high-pressure reactor 2 and is coaxially arranged. The force-balanced high-pressure reactor includes a force-balanced high-pressure reactor body 301 and a force-balanced high-pressure reactor cover 302.

[0044] The tensile loading system 4 includes a fixed rod 401 and a tensile rod 402. The tensile rod 402 penetrates the force-balancing autoclave 3 and the high-temperature autoclave 2, and is able to clamp the first end of the sample 9. The fixed rod 401 clamps the second end of the sample 9. The end face of the fixed rod 401, the end face of the tensile rod 402, and the inner wall of the high-temperature autoclave 2 form a high-temperature and high-pressure test chamber A. The tensile rod 402 has a protruding annular force-balancing structure. The distal end face of the annular force-balancing structure, the outer wall of the tensile rod 402, and the inner wall of the force-balancing autoclave 3 form a force-balancing high-pressure chamber B. The hydraulic control system 5 is used to inject a first pressurizing medium into the high-temperature and high-pressure test chamber A and a second pressurizing medium into the force-balancing high-pressure chamber B. The second pressurizing medium is used to balance the axial force generated in the high-temperature and high-pressure test chamber A, wherein the axial force includes an initial axial force and an additional axial force.

[0045] In this embodiment, a separate force-balancing autoclave is used to form a high-temperature, high-pressure testing chamber and a force-balancing high-pressure chamber. By controlling the hydraulic control system to inject a second pressurizing medium into the force-balancing high-pressure chamber, real-time dynamic balancing of the axial force generated during the tensile process of the sample under high temperature and high pressure is achieved. This effectively counteracts the initial axial force generated by the high-pressure medium acting on the end face of the tensile rod, and can more actively respond to the sudden change in dynamic additional axial force caused by sample yielding and necking, thereby improving the reliability of the test results. At the same time, fixing the high-temperature resistant force sensor to the side of the fixed rod avoids the frictional resistance generated between the sealing rings under conventional settings, further improving the reliability of the test results.

[0046] As a feasible implementation method, the frame assembly 1 provides a stable mechanical support and installation foundation for the entire testing machine. It mainly includes a platform 101, a control panel 102, a fixed crossbeam end 103, a supporting crossbeam end 105, and first to fourth supporting legs 106, 107, 108, and 109. The fixed crossbeam end 103 and the supporting crossbeam end 105 are arranged opposite each other, forming a robust gantry frame. The high-temperature autoclave 2 and the force-balanced autoclave 3 are installed side-by-side within this frame, specifically between the fixed crossbeam end 103 and the supporting crossbeam end 105. Multiple supporting legs 106-109 are fixed below the platform 101 to ensure overall equipment stability. Furthermore, a disassembly plate 104 can be provided on the side of the frame for easy maintenance and inspection of internal components. The high-temperature force sensor 6 is fixed to the inner wall of the autoclave lid 202 and connected to a fixing rod 401, thus providing better stability for more accurate measurement of the tensile force applied to the sample. In addition, the tensile testing machine also includes a control panel 102, which can interact with the user to generate control commands for various components in the tensile testing machine.

[0047] The specific structure of the tensile loading system 4 will be described next, which can be combined with... Figure 3 and Figure 4 , Figure 3 This invention provides a schematic diagram of the tensile loading system of a tensile testing machine. Figure 4 A schematic diagram of the moving guide rail slider mechanism in the tensile loading system is further shown.

[0048] As one feasible implementation, the tensile loading system 4 includes a fixing rod 401 arranged between the high-temperature and high-pressure reactor body 201 and the high-temperature and high-pressure reactor cover 202. The sample 9 is connected between the clamping end of the fixing rod 401 and the clamping end of the tension rod 402. The fixing rod 401 is fixed to the high-temperature and high-pressure reactor cover 202 by bolts. The tension rod 402 passes through the high-temperature and high-pressure reactor 2 and the force-balancing high-pressure reactor 3 and is connected to the movable loading crossbeam 403.

[0049] The moving guide rail slider mechanism mainly consists of a moving guide rail 405, a first slider 406, and a second slider 407. The moving guide rail 405 is fixedly mounted on the testing machine frame 1 parallel to the tensile loading axis, providing high-precision linear motion guidance for the moving loading beam 403. The first slider 406 and the second slider 407 are respectively connected to the bottom sides of the moving loading beam 403 via guide rail connecting blocks 408, allowing the moving loading beam 403 to slide smoothly along the moving guide rail 405. The guiding mechanism works in conjunction with the ball screw 404 drive system: the ball screw 404 is also installed parallel to the loading axis, and its tapered roller bearings 410 at both ends are supported on the frame; the ball nuts 409 on the ball screw 404 are directly fixed to the moving loading beam 403 through the nut seat; the servo motor 414 drives the synchronous pulley 411 and the synchronous belt 412 through the coupling 413, thereby driving the ball screw 404 to rotate, converting the rotational motion into precise linear displacement of the ball nuts 409 and the beam. The mechanism bears the radial force and eliminates lateral backlash, while the drive system provides precise axial driving force. The combination of the two ensures that the tension rod 402 always maintains strict axial alignment during loading, avoiding additional bending moments caused by off-center loading, thus meeting the accuracy and stability requirements of tensile tests under high temperature and high pressure conditions.

[0050] Optionally, the side wall of the high-temperature and high-pressure reactor 2 is provided with a first pressure inlet 203 for injecting the first pressurizing medium into the high-temperature and high-pressure test chamber A and a second pressure inlet 204 for discharging the first pressurizing medium; the side wall of the force-balanced high-pressure reactor 3 is provided with a third pressure inlet 303 for injecting the second pressurizing medium into the force-balanced high-pressure chamber.

[0051] In this embodiment, the high-temperature high-pressure vessel 2 and the force-balanced high-pressure vessel 3 are provided with pressure inlet holes, which are connected to a high-pressure source controlled by the hydraulic control system 5 through high-pressure pipelines. The first pressurizing medium can be gas or liquid.

[0052] Specifically, the hydraulic control system 5 is equipped with a high-pressure source and is connected to the first pressure head 501 and the second pressure head 502 via high-pressure pipelines. The high-temperature and high-pressure reactor 2 has a first pressure-inlet hole 203 for injecting the first pressurizing medium and a second pressure-inlet hole 204 for discharging the pressurizing medium on its side wall, which are connected to the first pressure head 501 and the second pressure head 502 respectively. The hydraulic control system 5 controls the pressurization and depressurization of the pressurizing medium. This structure and the hydraulic control system 5 enable the automatic injection of the first pressurizing medium into the high-temperature and high-pressure test chamber A during tensile loading, facilitating control. When the first pressure head 501 injects and replenishes the pressure of the first pressurizing medium, the second pressure-inlet hole 204 is closed, ensuring the stability of the high-pressure environment.

[0053] Similarly, the side wall of the force-balancing high-pressure vessel 3 is provided with a third pressure inlet 303 for injecting the second pressurizing medium, and is connected to the third pressure inlet head 503. The hydraulic control system 5 is used to control the servo valve to inject the second pressurizing medium into the force-balancing high-pressure chamber B through the third pressure inlet head 503. The second pressurizing medium can be gas or liquid. The third pressure inlet is used to realize the pressurization control of the force-balancing high-pressure chamber B, thereby achieving dynamic balance of axial force.

[0054] Optionally, the annular force balance structure is provided with a mounting groove recessed in the circumference, and a sealing element is provided in the mounting groove to isolate the high-temperature and high-pressure test chamber from the force balance high-pressure chamber.

[0055] In this embodiment, installing a seal at the notch can prevent the flow of the second pressurized medium within the force-balanced high-pressure chamber.

[0056] Optionally, the effective cross-sectional area S of the annular force balance structure satisfies the following relationship:

[0057] S=π×(R 2 -r 2 )

[0058] In the formula, R is the radius of the tension rod 402, and r is the radius of the gauge length section of the specimen 9.

[0059] In this embodiment, the high pressure generated by the second pressurizing medium on the cross section of the annular force balance structure of the tension rod 402 generates an axial force opposite to the direction of tension, ensuring the realization of the axial force balance function. The above formula reflects the key relationship of the unit pressure change generating unit balance force control, and provides a theoretical basis for the subsequent compensation of additional axial force during the test process.

[0060] Optionally, the high-temperature and high-pressure autoclave 2 is wrapped with an insulation layer 8, and the electromagnetic induction heating coil 7 is wound around the insulation layer 8.

[0061] In this embodiment, the high-temperature and high-pressure reactor 2 is wrapped with an insulation layer 8 and multiple turns of an electromagnetic induction heating coil 7, which heats the reactor 2 and, through heat transfer, raises the first pressurized medium (including gas and liquid) in the high-temperature and high-pressure test chamber A to the target test temperature, thus achieving a high-temperature environment. By connecting an AC power source to the electromagnetic induction heating coil 7, a ring-shaped current magnetic field is generated using the principle of electromagnetic induction, producing eddy currents that heat the high-temperature and high-pressure reactor body 201. The insulation layer 8 can be made of, but is not limited to, aerogel insulation rock wool, to ensure the heating rate and temperature uniformity requirements, thus ensuring the stability of the high-temperature environment during the tensile test.

[0062] The following section, using this embodiment, proposes a testing method for the aforementioned high-temperature and high-pressure tensile testing machine, explaining the specific process of balancing the initial axial force and the additional axial force. As mentioned in the background, for current solutions where the force sensor is placed outside the high-temperature and high-pressure autoclave, the data measured by the force sensor equals the initial axial force before tension + the applied tensile force + the additional axial force caused by necking + the frictional resistance of the sealing ring. The method proposed in this embodiment, on the one hand, avoids the frictional resistance caused by the sealing ring by placing the high-temperature resistant force sensor on one side of the fixed rod. On the other hand, by setting up a force-balancing high-pressure chamber, the initial axial force and the additional axial force are dynamically balanced by adjusting the pressure in the force-balancing high-pressure chamber, thus making the measurement data more accurate. Specifically, Figure 5 This embodiment illustrates a testing method that can be automated during a tensile test, or the steps of the method can be decoupled, allowing the user to complete each step through interaction with the control panel 102. The testing method includes:

[0063] S101, after completing the sample loading in response to user instructions, controls the electromagnetic induction heating coil to heat the high-temperature autoclave to the target temperature.

[0064] S102, by means of a hydraulic control system, a first pressurizing medium is injected into the high-temperature and high-pressure test chamber to make the pressure of the high-temperature and high-pressure test chamber reach the target pressure, and then a second pressurizing medium is injected into the force balancing high-pressure chamber to balance the initial axial force generated by the high-temperature and high-pressure test chamber at the target temperature and target pressure.

[0065] S101 and S102 describe the processes of heating and pressurizing the high-temperature and high-pressure test chamber containing the specimen and balancing the initial axial force before the tensile test. This embodiment uses TC4 titanium alloy as the specimen, simulating the high-temperature and high-pressure mechanical properties under a drilling environment of 300℃ and 175MPa at a depth of 10,000 meters. After the user completes the specimen loading, the target temperature T=300℃ and target pressure P=175MPa are set via the control panel. Then, the electromagnetic induction heating coil heats the high-temperature and high-pressure autoclave to the target temperature, and the hydraulic control system injects the first pressurizing medium, water, into the high-temperature and high-pressure test chamber to achieve the target pressure.

[0066] Optionally, after injecting a first pressurizing medium into the high-temperature and high-pressure test chamber using a hydraulic control system to bring the pressure of the high-temperature and high-pressure test chamber to the target pressure, a second pressurizing medium is injected into the force-balancing high-pressure chamber to balance the initial axial force generated by the high-temperature and high-pressure test chamber at the target temperature and target pressure. This includes: controlling the hydraulic control system to inject the first pressurizing medium into the high-temperature and high-pressure test chamber to bring the pressure of the high-temperature and high-pressure test chamber to the target pressure P; controlling the hydraulic control system to inject the second pressurizing medium into the force-balancing high-pressure chamber to bring the pressure of the force-balancing high-pressure chamber to the target pressure P0; wherein the force generated by the force-balancing high-pressure chamber at pressure P0 is used to balance the initial axial force generated by the high-temperature and high-pressure test chamber at the target temperature and target pressure P.

[0067] In step S102, as the pressure in the high-temperature and high-pressure test chamber increases, a second pressurized medium, water, is injected into the force-balancing high-pressure chamber until the pressure reaches P0. The force generated in the force-balancing high-pressure chamber at pressure P0 is equal in magnitude to the initial axial force, thus counteracting the initial axial force generated in the high-temperature and high-pressure test chamber at the target temperature T and target pressure P. In other words, static equilibrium of the initial axial force is achieved before the tensile test. Specifically, the force generated in the force-balancing high-pressure chamber at pressure P0 is equal in magnitude to the initial axial force generated in the high-temperature and high-pressure test chamber at the target temperature T and target pressure P. Ignoring other external environmental factors and the influence of errors, the pressure in the force-balancing high-pressure chamber is P0 = P, and the initial axial force is F. a =P×S, where S is the effective cross-sectional area of ​​the ring-shaped force balance structure.

[0068] S103, during the tensile test of the sample using a tensile loading system, the real-time value of the tensile force measured by the high-temperature force sensor is obtained.

[0069] The sample is subjected to a tensile test using a tensile loading system at a preset tensile rate, and the real-time value of the tensile force measured by the force sensor is obtained. In this embodiment, the preset tensile rate is set to 0.2 mm / min.

[0070] S104, based on the real-time change of the tensile force, injects a second pressurized medium into the force balance high-pressure chamber by means of a hydraulic control system to balance the additional axial force generated by the necking phenomenon.

[0071] Specifically, based on the change in the real-time value of the tensile force, a second pressurized medium is injected into the force balance high-pressure chamber by means of the hydraulic control system to balance the additional axial force generated by the necking phenomenon. This includes: calculating the difference between the real-time value of the tensile force at the current moment and the real-time value of the tensile force at the previous moment; if the absolute value of the difference is detected to be greater than a preset deviation threshold, it is determined that a necking phenomenon has occurred, and the hydraulic control system is controlled according to the difference.

[0072] Furthermore, if the absolute value of the detected difference exceeds a preset deviation threshold, a necking phenomenon is determined to have occurred, and the hydraulic control system is controlled based on the difference, including: based on the real-time value of the tensile force F at the current moment. s The real-time value of the tensile force F at the previous moment m Calculate the difference e; if the absolute value of the difference e is greater than the preset deviation threshold, control the hydraulic control system to inject a second pressurizing medium into the force balance high-pressure chamber until the pressure in the force balance high-pressure chamber is adjusted to P. b Among them, P b =P0+e / S, where P0 is the pressure of the high-pressure chamber before adjustment and S is the effective cross-sectional area of ​​the annular force balance structure.

[0073] In step S104, during the uniform tensile stage, the material deformation force increases slowly and steadily with the hardening effect. The force growth curve monitored by the controller is smooth, meaning the real-time tensile force measured by the force sensor increases uniformly. When necking occurs in the specimen, the local cross-sectional area of ​​the specimen decreases sharply. The axial force at the necking point increases due to the action of the first pressurizing medium, causing a sharp drop in the total tensile force. The speed and magnitude of this drop far exceed the rate of normal material hardening or softening. The force growth curve corresponding to the real-time tensile force value will decline rapidly, at which point the real-time tensile force value F before the necking phenomenon is obtained. m .

[0074] Then calculate the real-time value of tensile force F. s The real-time value of the tensile force F at the previous moment m If the absolute value of the difference e exceeds a preset deviation threshold, the system determines that a necking phenomenon has occurred. At this point, based on the difference e and the effective cross-sectional area S of the annular force balance structure, the system continuously calculates the pressure P that needs to be adjusted in the force balance high-pressure chamber. b The hydraulic control system injects a second pressurizing medium into the force balance high-pressure chamber to achieve dynamic balance of the additional axial force generated by the necking phenomenon. In this embodiment, a standard cylindrical specimen of specific dimensions processed according to GB / T228.2-2015 is selected, using a TC4 titanium alloy bar with an original diameter of d0=10mm and a gauge length of L0=50mm. The diameters of the tension rod 402 and the fixing rod 401 are designed to be D=50mm, then the radius of the annular force balance structure is... .

[0075] Optionally, after injecting a second pressurizing medium into the force-balancing high-pressure chamber to balance the additional axial force generated by the necking phenomenon according to the real-time change of the tensile force, the method further includes: performing a tensile test on the specimen based on the tensile loading system in response to the user's test command until the specimen breaks and generating test data; and depressurizing and cleaning the high-temperature high-pressure test chamber and the force-balancing high-pressure chamber in response to the user's cleaning command.

[0076] In this embodiment, under dynamic equilibrium of axial force, tensile testing continues until the TC4 titanium alloy sample fractures. After the test, the machine is stopped, and test data is generated, including fracture length, diameter at the fracture surface, tensile strength, yield strength, elastic modulus, elongation after fracture, reduction of area, and fracture strength. Further, after the high-temperature autoclave temperature returns to room temperature, the user can depressurize the high-temperature high-pressure test chamber and the force balance high-pressure chamber via the control panel. After depressurization, any remaining water in the chambers is purged, and the fractured sample is removed.

[0077] As described above, this embodiment establishes a high-temperature, high-pressure testing chamber and a force-balancing high-pressure chamber by setting up an independent force-balancing autoclave. By controlling the hydraulic control system to inject a second pressurizing medium into the force-balancing high-pressure chamber, real-time dynamic balancing of the axial force generated during sample tensile testing under high-temperature, high-pressure conditions is achieved. This effectively counteracts the initial axial force generated by the high-pressure medium acting on the end face of the tensile rod, and more actively responds to sudden changes in dynamic additional axial force caused by sample yielding and necking, thereby improving the reliability of the test results. Simultaneously, fixing the high-temperature resistant force sensor to the fixed rod side avoids the frictional resistance generated between the sealing rings under conventional settings, further improving the reliability of the test results.

[0078] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0079] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0080] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0081] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0082] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A high-temperature and high-pressure tensile testing machine, comprising a frame assembly (1), a high-temperature and high-pressure autoclave (2) disposed on the frame assembly (1), and an electromagnetic induction heating coil (7) for heating the high-temperature and high-pressure autoclave (2), characterized in that, It also includes a force-balanced autoclave (3), a tensile loading system (4), a hydraulic control system (5), and a high-temperature resistant force sensor (6): The force-balanced high-pressure vessel (3) is mounted on the frame assembly (1), and the force-balanced high-pressure vessel (3) is located on one side of the high-temperature high-pressure vessel (2) and is coaxially arranged. The tensile loading system (4) includes a fixed rod (401) and a tensile rod (402). The tensile rod (402) passes through the force balance autoclave (3) and the high temperature autoclave (2) and can clamp the first end of the sample (9). The fixed rod (401) clamps the second end of the sample (9). The end face of the fixed rod (401), the end face of the tension rod (402), and the inner wall of the high-temperature and high-pressure reactor (2) form a high-temperature and high-pressure test chamber A. The tension rod (402) is provided with a ring-shaped force balance structure. The far end face of the ring-shaped force balance structure, the outer wall of the tension rod (402), and the inner wall of the force balance high-pressure reactor (3) form a force balance high-pressure chamber B. The hydraulic control system (5) is used to inject a first pressurizing medium into the high temperature and high pressure test chamber A and a second pressurizing medium into the force balance high pressure chamber B. The second pressurizing medium is used to balance the axial force generated in the high temperature and high pressure test chamber A. The axial force includes an initial axial force and an additional axial force. The high-temperature resistant force sensor (6) is connected to the fixed rod (401) and is used to measure the tensile force applied to the sample (9).

2. The high-temperature and high-pressure tensile testing machine as described in claim 1, characterized in that: The high-temperature and high-pressure reactor (2) has a first pressure inlet (203) for injecting the first pressurized medium into the high-temperature and high-pressure test chamber A and a second pressure inlet (204) for discharging the first pressurized medium. The side wall of the force-balanced high-pressure vessel (3) is provided with a third pressure inlet (303) for injecting the second pressurizing medium into the force-balanced high-pressure chamber.

3. The high-temperature and high-pressure tensile testing machine as described in claim 1, characterized in that: The annular force balance structure has a recessed mounting groove on its circumference, and a sealing element is provided in the mounting groove to isolate the high temperature and high pressure test chamber from the force balance high pressure chamber.

4. The high-temperature and high-pressure tensile testing machine as described in claim 1, characterized in that: The effective cross-sectional area S of the annular force balance structure satisfies the following relationship: S=π×(R 2 -r 2 ); In the formula, R is the radius of the tension rod (402), and r is the radius of the gauge length of the specimen (9).

5. The high-temperature and high-pressure tensile testing machine as described in claim 1, characterized in that: The high-temperature and high-pressure autoclave (2) is wrapped with a heat insulation layer (8) on the outside, and the electromagnetic induction heating coil (7) is wound around the heat insulation layer (8).

6. A testing method, using the high-temperature, high-pressure tensile testing machine as described in any one of claims 1-5, characterized in that, include: After the sample (9) is filled in response to the user's instructions, the electromagnetic induction heating coil (7) is controlled to heat the high-temperature and high-pressure autoclave (2) to the target temperature. With the help of the hydraulic control system (5), a first pressurizing medium is injected into the high temperature and high pressure test chamber A to make the pressure of the high temperature and high pressure test chamber A reach the target pressure, and then a second pressurizing medium is injected into the force balancing high pressure chamber B to balance the initial axial force generated by the high temperature and high pressure of the high temperature and high pressure test chamber A at the target temperature and the target pressure. During the tensile test of the specimen (9) by means of the tensile loading system (4), the real-time value of the tensile force measured by the high temperature force sensor (6) is obtained in real time. Based on the real-time change of the tensile force, a second pressurized medium is injected into the force-balancing high-pressure chamber B by means of the hydraulic control system (5) to balance the additional axial force generated by the necking phenomenon.

7. The test method as described in claim 6, characterized in that, Based on the real-time change in the tensile force, a second pressurizing medium for balancing the additional axial force generated by the necking phenomenon is injected into the force-balancing high-pressure chamber B by means of the hydraulic control system (5), including: Calculate the difference between the current real-time value of the tensile force and the previous real-time value of the tensile force; If the absolute value of the difference is detected to be greater than a preset deviation threshold, it is determined that a necking phenomenon has occurred, and the hydraulic control system (5) is controlled according to the difference.

8. The test method as described in claim 7, characterized in that, If the absolute value of the detected difference is greater than a preset deviation threshold, it is determined that a necking phenomenon has occurred, and the hydraulic control system (5) is controlled according to the difference, including: Based on the current real-time value of the tensile force F s The real-time value of the tensile force F at the previous moment m Calculate the difference e; If the absolute value of the difference e is detected to be greater than a preset deviation threshold, the hydraulic control system (5) is controlled to inject the second pressurizing medium into the force balance high-pressure chamber B until the pressure of the force balance high-pressure chamber B is adjusted to P. b ; Among them, P b =P0+e / S, where P0 is the pressure of the high-pressure chamber B before adjustment, and S is the effective cross-sectional area of ​​the annular force balancing structure.

9. The test method as described in claim 6, characterized in that, After the hydraulic control system (5) injects a first pressurizing medium into the high-temperature and high-pressure test chamber A to bring the pressure of the high-temperature and high-pressure test chamber A to the target pressure, a second pressurizing medium is injected into the force-balancing high-pressure chamber B to balance the initial axial force generated by the high-temperature and high-pressure test chamber A at the target temperature and the target pressure. This includes: The hydraulic control system (5) is controlled to inject the first pressurizing medium into the high temperature and high pressure test chamber A, so that the pressure of the high temperature and high pressure test chamber A reaches the target pressure P; The hydraulic control system (5) is controlled to inject the second pressurizing medium into the force balancing high-pressure chamber B, so that the pressure of the force balancing high-pressure chamber B reaches P0; wherein, the force generated by the force balancing high-pressure chamber B under the pressure of P0 is used to balance the initial axial force generated by the high temperature and high pressure test chamber A under the target temperature and target pressure P.

10. The test method as described in claim 6, characterized in that, After injecting a second pressurizing medium into the force-balancing high-pressure chamber B to balance the additional axial force generated by the necking phenomenon, based on the real-time change of the tensile force value using the hydraulic control system (5), the method further includes: In response to the user's test command, the tensile test is performed on the specimen (9) based on the tensile loading system (4) until the specimen (9) breaks, and test data is generated. In response to the user's cleaning command, the high-temperature and high-pressure test chamber A and the force balance high-pressure chamber B are depressurized and cleaned.

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