Deep sea simulation test device for dynamic and static loading process

Abstract

The invention belongs to the technical field of metal material stress corrosion test, and relates to a deep sea simulation test device for dynamic and static loading process, the main structure of the deep sea simulation test device comprises a pressure-resistant test cabin, and a loading sample piece, a pressure-resistant reference electrode and an annular auxiliary electrode arranged in the pressure-resistant test cabin, the loading sample piece is completely arranged in the pressure-resistant test cabin, and the annular auxiliary electrode is arranged in the pressure-resistant reference electrode. An adapter is connected with a dynamic and static loading system after penetrating through a cabin to perform static or dynamic stress loading, a pressure-resistant electrochemical test system is adopted to perform electrochemical characterization, test or polarization potential application, and a multi-factor control system is adopted to control main deep sea environmental factors such as temperature, pressure and dissolved oxygen content. High-precision and high-reliability test data can be quickly obtained, and corrosion electrochemical behaviors in stress corrosion and corrosion fatigue processes of metal materials in a deep sea simulation environment can be more truly reflected; the method provides support for metal material in-situ slow strain rate stress corrosion and corrosion fatigue test in a deep sea simulation environment and electrochemical test and characterization in the process.

Description

Technical Field:

[0001] The present invention belongs to the technical field of stress corrosion testing of metal materials, and relates to a deep-sea simulation test device for dynamic and static loading processes, simulating the environment of slow strain rate testing and axial fatigue testing of metal materials under hydrostatic pressure conditions. Background Art:

[0002] Conducting in-situ stress corrosion tests under simulated deep-sea environments is an important means to study the mechanism of stress corrosion behavior of materials in deep-sea environments. When conducting stress corrosion tests under simulated deep-sea environments, the metal specimens under stress must be in a high hydrostatic pressure environment. Once the water seal fails and the hydrostatic pressure cannot be maintained at the preset value, the test results will be affected. In the existing technology, for stress corrosion tests under hydrostatic pressure, generally, after using a constant displacement and constant load tooling to keep the test specimen in a certain tensile stress state, it is placed in a deep-sea simulation experimental device to carry out deep-sea simulation environment immersion tests for different periods, and the mechanical loss situation is evaluated. For example, a stress corrosion test device for deep-sea environments disclosed in Chinese Patent No. 201711280845.0 includes: a bolt, a specimen, an insulating spring, a nut, and a data collection and storage unit; the bolt has a screw rod with an external thread, which is made of a corrosion-resistant material. The specimen is processed from a plate-shaped material to be tested into a non-closed shape with an opening. Holes are drilled on the wall of the non-closed shape, and after insulation treatment, it is sleeved on the screw rod. The insulating spring is sleeved on the screw rod and abuts against the specimen. A nut is installed at the end of the screw rod; using the insulating spring as a stress generation unit, the accumulated elastic potential energy acts on the specimen, causing the specimen to deform, thereby causing a change in the load of the part connected to the data collection and storage unit, triggering a change in the electrical signal, and realizing the test of the stress corrosion performance of the specimen. It also includes a sliding rheostat. The sliding rheostat is connected to the data collection and storage unit. The sliding contact of the sliding rheostat moves with the deformation of the specimen, thereby causing a change in the load of the part connected to the data collection and storage unit. An insulating gasket is also sleeved on the screw rod between the specimen and the insulating spring. The insulating gasket is embedded with a magnet. Under the attraction of the magnet, the sliding contact of the sliding rheostat slides with the insulating gasket, thereby changing the resistance of the sliding rheostat. The data collection and storage unit includes a power supply, a current detection module, and a recording and storage module. The current detection module is connected in series in the closed circuit formed by the power supply and the load. The recording and storage module is connected to the current detection module to store the current formed in the closed circuit. The data collection and storage unit is sealed in a pressure-resistant tank or integrated in the internal cavity of the bolt. The sliding rheostat is embedded in the internal cavity of the bolt. The non-closed shape is a C-shaped, U-shaped, M-shaped, or symmetric non-closed shape bent at any angle. Its test period varies with the applied stress magnitude and specimen material, and is generally not less than 15 days.A constant load stress corrosion test device for simulating deep - sea environment disclosed in Chinese Patent No. 202211577084.6, the main structure of which includes a high - pressure test chamber, a bearing frame, a fixture, a bottom loading bolt, a tension rod, a stress ring, a force - measuring bearing, a top loading nut and a test system; a bearing frame is arranged inside the high - pressure test chamber, a fixture is arranged on the bearing frame, the bottom end of the fixture is fixed on the bearing frame through the bottom loading bolt, the top end is connected with the tension rod, the top end of the tension rod passes through the high - pressure test chamber and then passes through the stress ring, and a force - measuring bearing and a top loading nut are arranged. A specimen is clamped on the fixture, the test system is respectively connected with the force - measuring bearing and the specimen. A drain pipe is arranged at the bottom of the high - pressure test chamber, a pressure - adding water injection pipe and a watertight joint are arranged at the top, and its hydrostatic pressure is adjusted through the drain pipe and the pressure - adding water injection pipe. A sealing pair is arranged between the high - pressure test chamber and the tension rod, and the sealing pair enables the high - pressure test chamber not to leak under the test pressure and does not interfere with the movement of the tension rod. The stress ring is connected with the high - pressure test chamber through a fixed pin, a drum - shaped hole for preventing the rotation and dislocation of the tension rod is opened at the top of the stress ring, a gasket, a force - measuring bearing, a slip ring and a top loading nut are sequentially arranged after the end of the tension rod passes through the drum - shaped hole. The specimen is connected with the fixture through an insulating ring and a pin, and is connected with the watertight joint through a watertight cable. The test system is respectively connected with the watertight joint and the force - measuring bearing through test cables. Its test period is relatively long.A device for evaluating the service behavior of pipes, disclosed in Chinese Patent No. 202411758305.9, includes an autoclave, a fretting wear loading mechanism, a stress corrosion test mechanism, a fixing mechanism, and a temperature and pressure control system. The autoclave is used to accommodate the test pipes. The fretting wear loading mechanism is connected to the autoclave and is used to apply small-amplitude vibrations to the test pipes. The stress corrosion test mechanism is connected to the autoclave and is used to apply stress corrosion loads to the test pipes. The fixing mechanism is installed inside the autoclave and is used to fix the position of the test pipes. The temperature and pressure control system is used to control the temperature and pressure of the water inside the autoclave. The fretting wear loading mechanism includes a fretting wear loader, a fretting wear connecting rod, a small-amplitude vibration connecting plate, a small-amplitude vibration connecting rod, and a fretting wear indenter. The two ends of the fretting wear connecting rod are respectively connected to the fretting wear loader and the small-amplitude vibration connecting plate, and the fretting wear connecting rod is fixedly connected to the autoclave. The two ends of the small-amplitude vibration connecting rod are respectively connected to the small-amplitude vibration connecting plate and the fretting wear indenter. The fretting wear indenter is used to contact the side wall of the test pipe. The number of the small-amplitude vibration connecting rod and the fretting wear indenter is at least two. The stress corrosion test mechanism includes a stress corrosion tester, a stress corrosion test machine connecting rod, and a pipe lower fixture. The two ends of the stress corrosion test machine connecting rod are respectively connected to the stress corrosion tester and the pipe lower fixture, and the stress corrosion test machine connecting rod is fixedly connected to the autoclave. The pipe lower fixture is used to contact the lower end face of the test pipe. The fretting wear connecting rod is connected to the autoclave through a first seal. The stress corrosion test machine connecting rod is connected to the autoclave through a second seal. The fixing mechanism includes a fixing connecting rod, a fixing connecting plate, and a pipe upper fixture. The fixing connecting rod is fixedly installed inside the autoclave. The fixing connecting plate is fixedly connected to the fixing connecting rod. The pipe upper fixture is fixedly connected to the fixing connecting plate. The pipe lower fixture is used to contact the upper end face of the test pipe. Its structure is complex, and it is impossible to accurately control environmental parameters such as temperature and dissolved oxygen, nor can it perform in-situ electrochemical testing and cathodic polarization online, and it cannot conduct hydrogen embrittlement sensitivity tests on materials in the deep-sea environment. Therefore, it is necessary to research and develop a deep-sea simulation test device with a simple structure, high hydrostatic pressure, accurate control of environmental parameters, capable of in-situ electrochemical testing, and dedicated to dynamic and static loading processes. Summary of the Invention:

[0003] The purpose of the present invention is to overcome the shortcomings of the existing technology, research and design a deep-sea simulation test device for dynamic and static loading processes, so as to realize in-situ slow strain rate stress corrosion tests and corrosion fatigue tests of metal materials in a simulated deep-sea environment, and conduct electrochemical testing or characterization of metal materials.

[0004] To achieve the above purpose, the main structure of a deep-sea simulation test device for dynamic and static loading processes according to the present invention includes a pressure-resistant test chamber and a loading specimen, a pressure-resistant reference electrode, and an annular auxiliary electrode arranged therein. Among them,

[0005] The pressure-resistant test chamber is made of pressure-resistant materials. Pressure-resistant glass is selected within 10 MPa, and corrosion-resistant stainless steel is selected above 10 MPa. It has a sandwich layer, a test chamber cover, and a bracket.

[0006] The loaded specimen is a non-standard dumbbell-shaped round bar specimen or a standard round bar proportional specimen specified in GB / T 228.1-2021. It is completely placed in the pressure-resistant test chamber, and static or dynamic stress is applied through a connecting loading adapter at both ends. It is connected to the adapter in a hanging manner, and a pressure-resistant insulating gasket is used to insulate and isolate the two when hanging.

[0007] There are a cooling water inlet, a seawater inlet, and an air inlet on the test chamber cover.

[0008] The bracket is used to support the pressure-resistant test chamber and can adjust the height to suit different test requirements.

[0009] The pressure-resistant reference electrode is a solid silver-silver chloride or solid silver-halide pressure-resistant reference electrode, which is arranged between the loaded specimen and the annular auxiliary electrode.

[0010] The annular auxiliary electrode is made of a pressure-resistant and polarization-resistant material such as a noble metal oxide anode or a silver-containing hard solid graphite.

[0011] The adapter passes through the center of the test chamber cover 4 and the center of the bracket through the chamber. A seal is provided at the penetration point to provide pressure resistance and water sealing during the dynamic and static loading processes.

[0012] The pressure-resistant insulating gasket is made of a hard insulating material such as ceramic or bakelite, and the insulation resistance is greater than 100 MΩ.

[0013] Before using a deep-sea simulation test device for dynamic and static loading processes involved in the present invention, it is first connected to a multi-factor control system composed of a temperature control system, a dissolved oxygen control system, and a pressure control system to regulate the temperature, dissolved oxygen content, and hydrostatic pressure or alternating pressure of the seawater in the pressure-resistant test chamber. Among them, the pressure control system will dynamically adjust the hydrostatic pressure or alternating pressure according to the plastic deformation of the loaded specimen during the dynamic and static loading processes to ensure that the hydrostatic pressure or alternating pressure is stable at the set value throughout the test process.

[0014] The specific technological process during use includes the following steps:

[0015] (1) Design the structure of the loaded specimen and machine it into shape according to the strength, hardness, and dimensions of the raw material.

[0016] (2) Place the loaded specimen in the pressure-resistant test chamber, adjust the positions of the pressure-resistant reference electrode and the annular auxiliary electrode, and perform pressure-resistant water sealing on the loaded specimen.

[0017] (3) Add seawater, activate the multi-factor control system, and control the temperature, dissolved oxygen content, and seawater pressure at the required values of the test;

[0018] (4) Adjust the coaxiality of the dynamic and static loading systems;

[0019] (5) Start the dynamic and static loading systems and the pressure-resistant electrochemistry test system simultaneously to conduct the test.

[0020] Compared with the prior art, in the present invention, the loaded specimen is completely placed in the pressure-resistant test chamber, connected to the dynamic and static loading systems through a through-hull adapter after passing through the hull, for static or dynamic stress loading, and a pressure-resistant electrochemistry test system is used for electrochemistry characterization, testing, or polarization potential application, and a multi-factor control system is used to control the main deep-sea environmental factors such as temperature, pressure, and dissolved oxygen content. It can quickly obtain test data with high accuracy and reliability, and more truly reflect the corrosion electrochemistry behavior during stress corrosion and corrosion fatigue of metal materials in the deep-sea simulation environment, providing a simple, fast, and economical device and method for in-situ slow strain rate stress corrosion and corrosion fatigue tests of metal materials in the deep-sea simulation environment and electrochemistry testing and characterization during this process; its structure is simple, and the principle is scientifically reliable, providing support for studying the corrosion behavior and mechanism of metal materials used in deep-sea environments under the interaction of stress or alternating stress - electrochemistry. Description of the drawings:

[0021] Figure 1 It is a schematic diagram of the main structure principle of the present invention.

[0022] Figure 2 It is a sectional view of the main structure of the present invention.

[0023] Figure 3 It is a schematic diagram of the usage state of the main structure of the present invention. Detailed implementation manners:

[0024] The present invention will be further described below through examples in conjunction with the drawings.

[0025] Example 1:

[0026] The main structure of the deep-sea simulation test device for dynamic and static loading processes involved in this example is as Figure 1-2As shown, it includes: an interlayer 1, a pressure test chamber 2, a loaded sample 3, a test chamber cover 4, a cooling water inlet 5, a seawater inlet 6, an air inlet 7, a cooling water outlet 8, a seawater outlet 9, a bracket 10, a pressure reference electrode 11, an annular auxiliary electrode 12, an adapter 13, a sealing member 14, a single-core pressure-resistant watertight cable 15, a pressure-resistant insulating gasket 16 and a two-core pressure-resistant watertight cable 17; the pressure test chamber 2 with an interlayer 1 is provided with a loaded sample 3 inside, and the test chamber cover 4 at the top is provided with a cooling water inlet 5, a seawater inlet 6 and An air inlet 7 is provided with a cooling water outlet 8, a seawater outlet 9 and a bracket 10 at the bottom; a pressure-resistant reference electrode 11 and an annular auxiliary electrode 12 are provided on the outside of the loaded sample 3, and the ends are connected to a switching joint 13. The switching joint 13 passes through the top and bottom of the pressure test chamber 2, and a sealing member 14 is provided at the passing point; in addition, the loaded sample 3 is connected to a single-core pressure-resistant watertight cable 15, and a pressure-resistant insulating gasket 16 is also provided between the loading sample 3 and the switching joint 13; the pressure-resistant reference electrode 11 and the annular auxiliary electrode 12 are connected to a two-core pressure-resistant watertight cable 17.

[0027] The loading specimen 3 involved in this embodiment is a non-proportional dumbbell-shaped round rod specimen, and the clamping end is threadedly connected to the hanging platform of the adapter 13. The connection is sealed with pressure-resistant water by a composite method of pressure-resistant insulating tape and epoxy glue to ensure that there is no risk of crevice corrosion. The diameter of the clamping end is consistent with the diameter of the adapter 13.

[0028] When using a deep-sea simulation test device for dynamic and static loading processes in this embodiment, it is first installed and connected, such as Figure 3 As shown:

[0029] Connect the cooling water inlet 3 and the cooling water outlet 10 to the temperature control system 20;

[0030] Connect the air inlet 4 to the dissolved oxygen control system 30;

[0031] Connect the seawater inlet 5 and the seawater outlet 11 to the pressure control system 40;

[0032] Connect the loading specimen 3 to the dynamic and static loading system 50 via the adapter 13;

[0033] The loading sample 3, the pressure-resistant reference electrode 11 and the annular auxiliary electrode 12 are respectively connected to the pressure-resistant electrochemical test system 60 through a single-core pressure-resistant watertight cable 15 and a two-core pressure-resistant watertight cable 17. The upper end of the single-core pressure-resistant watertight cable 15 passes through the upper end side of the adapter 13, and the lower end is connected to the loading sample 3 by a threaded manner. The pressure-resistant reference electrode 11 and the annular auxiliary electrode 12 are both connected to the two-core pressure-resistant watertight cable 17 in the pressure test chamber 2. The connection is vulcanized, epoxy resin cured, etc. to ensure waterproof and pressure resistance;

[0034] Connect the temperature control system 20, dissolved oxygen control system 30, pressure control system 40, dynamic and static loading system 50, and pressure-resistant electrochemical testing system 60 to the multi-factor control system 70 respectively;

[0035] When conducting the experiment, the specific technological process is as follows:

[0036] (1) According to the experimental requirements, process high-strength steel with high hardness into the loading specimen 3;

[0037] (2) Place the loading specimen 3 in the pressure-resistant test chamber 1, adjust the positions of the pressure-resistant reference electrode 11 and the annular auxiliary electrode 12, and use the seal 14 to conduct pressure-resistant water sealing on the loading specimen 3;

[0038] (3) Close the test chamber cover 4, add seawater, turn on the multi-factor control system 70, adjust the circulating water temperature of the water bath to 4°C through the temperature control system 20, adjust the dissolved oxygen content through the dissolved oxygen control system 30 to keep it at 3 mg / L, and control the pressure at 10 MPa through the pressure control system 40;

[0039] (4) Adjust the coaxiality of the dynamic and static loading system 50 (slow strain rate testing machine) to ensure no shear force during loading;

[0040] (5) Turn on the slow strain rate testing machine and the pressure-resistant electrochemical testing system 60 simultaneously to conduct the experiment.

Claims

1. A deep-sea simulation test device for dynamic and static loading processes, characterized in that The main structure includes a pressure test chamber, and a loading specimen, a pressure-resistant reference electrode, and a ring-shaped auxiliary electrode arranged therein.

2. The deep-sea simulation test device for the dynamic and static loading process according to claim 1, wherein The pressure test chamber has a sandwich layer, a test chamber cover, and a bracket, and is made of pressure-resistant materials. Pressure-resistant glass is selected within 10 MPa, and corrosion-resistant stainless steel is selected above 10 MPa.

3. The deep-sea simulation test device for the dynamic and static loading process according to claim 2, characterized in that, The loading specimen adopts a non-standard dumbbell-shaped round bar specimen or a standard round bar proportional specimen specified in GB / T 228.1-2021, and is completely placed in the pressure test chamber. Static or dynamic stress is applied to both ends through a connecting loading adapter. It is connected to the adapter in a hanging manner, and a pressure-resistant insulating gasket is used to insulate and isolate the two when hanging.

4. A deep-sea simulation test device for dynamic and static loading processes according to claim 3, characterized in that, The pressure-resistant reference electrode includes solid silver-silver chloride and solid silver-halide, and is arranged between the loading specimen and the ring-shaped auxiliary electrode.

5. A deep-sea simulation test device for dynamic and static loading processes according to claim 4, characterized in that, The ring-shaped auxiliary electrode is prepared from pressure-resistant and polarization-resistant materials such as noble metal oxide anodes or silver-containing hard solid graphite.

6. The deep-sea simulation test device for the dynamic and static loading process according to claim 5, characterized in that, Before use, it is first connected to a multi-factor control system composed of a temperature control system, a dissolved oxygen control system, and a pressure control system to regulate the temperature, dissolved oxygen content, and hydrostatic pressure or alternating pressure of the seawater in the pressure test chamber. Among them, the pressure control system will dynamically adjust the hydrostatic pressure or alternating pressure with the plastic deformation of the loading specimen during the dynamic and static loading process to ensure that the hydrostatic pressure or alternating pressure is stable at the set value throughout the test process.

7. A deep-sea simulation test device for dynamic and static loading processes according to claim 2, characterized in that, The test chamber cover is provided with a cooling water inlet, a seawater inlet, and an air inlet; the bracket is used to support the pressure test chamber and can adjust the height.

8. A deep-sea simulation test device for dynamic and static loading processes according to claim 3, characterized in that The adapter passes through the center of the test chamber cover and the center of the bracket through the chamber, and a seal is provided at the penetration point.

9. A deep-sea simulation test device for dynamic and static loading processes according to claim 7 or 8, characterized in that, The pressure-resistant insulating gasket is made of hard insulating materials such as ceramics and bakelite, and the insulation resistance is greater than 100 MΩ.

10. A deep-sea simulation test device for the dynamic and static loading process according to claim 6, characterized in that, The specific technological process during use is as follows: (1) Design the structure of the loading specimen and process it into shape according to the strength, hardness, and dimensions of the raw material. (2) Place the loading specimen in the pressure test chamber, adjust the positions of the pressure-resistant reference electrode and the ring-shaped auxiliary electrode, and perform pressure-resistant water sealing on the loading specimen. (3) Add seawater, start the multi-factor control system, and control the temperature, dissolved oxygen content, and seawater pressure at the test required values. (4) Adjust the coaxiality of the dynamic and static loading systems. (5) Start the dynamic and static loading systems and the pressure-resistant electrochemistry test system simultaneously to conduct the test.

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