An electrically adjustable stress corrosion specimen preparation device

Abstract

The utility model relates to stress corrosion field and material mechanics performance test field, concretely is a kind of electrically adjustable stress corrosion sample preparation device.The device has organism, sample export mechanism, replaceable mould group, hydraulic system, electric control system and automatic tightening system, and the sample export mechanism's sample temporary storage bin is connected with the sample guide groove with gradient on the intercommunication, the guide rail is relatively parallel and arranged on sample guide groove upper end, and replaceable mould group lower mould passes through the guide rail slot on guide rail on its upper guide rail slider and engages;Electric control system is installed above sample export mechanism, and electric control system is located in the side of lower mould and guide rail, and the hydraulic control cabinet of replaceable mould group upper mould is installed above lower mould, and hydraulic system is provided in the hydraulic control cabinet.The utility model can prepare different stress corrosion samples in batches by replacing upper mould and lower mould, combined with pressure sensor, replaceable mould system and automatic tightening system, realize automation and high repeatability, to improve test efficiency and data reliability.

Description

Technical Field

[0001] This utility model relates to the fields of stress corrosion and material mechanical property testing, specifically an electrically adjustable stress corrosion sample preparation device. Background Technology

[0002] In spent fuel reprocessing, some key equipment operates under the combined effects of nitric acid corrosion and stress, thus leading to stress corrosion. Stress corrosion testing is a crucial method for assessing the risk of brittle fracture in materials under the combined influence of stress and specific corrosive environments. Its necessity stems from multiple requirements, including engineering safety, materials research and development, and economic efficiency. Stress corrosion testing requires precise control of the bending stress and shape of the specimen. Traditional U-shaped stress corrosion specimen preparation methods (such as manual bending and bolt fixing) suffer from inaccurate stress control and low preparation efficiency, which can affect test repeatability and efficiency due to specimen quality issues.

[0003] Patent CN106908288A discloses a device for preparing stress corrosion U-shaped specimens, employing a frame, a manual extrusion device (handle, screw), and a roller die. Accuracy is controlled by a vernier caliper. Its drawbacks include low efficiency due to manual operation, reliance on manual judgment of the forming state, and poor repeatability. Patent CN216747058U discloses a specimen forming device for stress corrosion U-shaped bending tests, employing a frame, pneumatic cylinders, and forming pressure rods. Batch bending is achieved by controlling air pressure with a pressure boosting valve, but the pneumatic system experiences large pressure fluctuations and low pressure accuracy. Patent CN120160876A discloses a U-shaped specimen preparation device, mainly including a support base, a platform (groove, U-shaped groove, rotating shaft), and pressure application components (transmission mechanism, pressure head). It achieves specimen centering bending through mechanical positioning. Although the centering problem is solved, the reliance on mechanical transmission results in low stress control precision. It is impossible to flexibly control the application of the same load based on the elastic modulus of the sample, and it can only produce specimens of a single specification, which cannot be adapted to different material / shape requirements. Utility Model Content

[0004] The purpose of this invention is to provide an electrically adjustable stress corrosion specimen preparation device to solve the problems of inaccurate stress control and cumbersome operation in the current traditional methods for preparing stress corrosion specimens. It achieves high-precision and high-efficiency specimen preparation. Combined with a pressure sensor and a replaceable mold system, it achieves automation and high repeatability, thereby improving testing efficiency and data reliability.

[0005] The technical solution of this utility model is:

[0006] An electrically adjustable stress corrosion specimen preparation device is disclosed. The device comprises a main body, a specimen ejection mechanism, a replaceable mold assembly, a hydraulic system, an electrical control system, and an automatic tightening system. The specimen ejection mechanism is located at the bottom of the main body, and a hydraulic control cabinet housing the hydraulic system is located at the top of the main body. The specimen storage chamber of the specimen ejection mechanism is connected to a sloped specimen guide groove. A guide rail is parallel to the upper end of the specimen guide groove. The lower mold of the replaceable mold assembly engages with the guide rail groove on the guide rail via a slider on its upper guide rail. The electrical control system is installed above the specimen ejection mechanism, located on one side of the lower mold and guide rail. Above the lower mold is a hydraulic control cabinet housing the upper mold of the replaceable mold assembly. The hydraulic control cabinet contains the hydraulic system, with a hydraulic rod extending downwards. The lower end of the hydraulic rod corresponds to the upper end of the upper mold and is connected via a flange, threaded connection, or quick-change slot. The automatic tightening system is integrated to the side of the replaceable mold assembly or at an independent station. It connects to the two specimen holes at the end of the stress corrosion specimen and uses an infrared rangefinder or laser displacement sensor to measure the distance between the two arms of the stress corrosion specimen in real time.

[0007] The electric adjustable stress corrosion specimen preparation device includes an automatic tightening system comprising a movable worktable, a lead screw, a nut supply unit, an infrared rangefinder, and a bolt supply unit. The stress corrosion specimen is placed on the movable worktable, with a nut supply unit and a bolt supply unit respectively located on both sides. An infrared rangefinder or laser displacement sensor is installed inside each of the nut supply unit and bolt supply unit. The lead screw is located at the lower end of the bolt supply unit and corresponds to one end of the bolt output from the bolt supply unit. The lead screw is connected to an electrical control system, and a motor drives the lead screw to push the bolt through the two specimen holes at the end of the stress corrosion specimen. The protruding end of the bolt is connected to the nut output from the nut supply unit.

[0008] The electrically adjustable stress corrosion specimen preparation device comprises an upper mold and a lower mold. The upper mold has a flange interface at the top, which is threaded onto flange I. The flange II at the lower end of the hydraulic rod is bolted to flange I at the upper end of the upper mold and uniformly tightened. A spherical gasket is installed at the flange connection. The lower mold has T-shaped guide rail sliders on both sides at the bottom, each T-shaped guide rail slider engaging with the corresponding T-shaped guide rail groove on the guide rail in a sliding fit. A lower mold positioning groove is provided at the middle position of the top of the lower mold, which is aligned with the corresponding middle guide rail positioning groove on the guide rail to ensure that the upper and lower molds fit together. The lower mold has one or more spaced and parallel concave mold grooves, and the upper mold has punches that match the position and number of the concave mold grooves.

[0009] The electric adjustable stress corrosion specimen preparation device has N cavity grooves equidistantly arranged along the length of the lower mold working surface. Each cavity groove has a specimen groove at its upper end. Two horizontal shafts are provided below the specimen grooves. Each horizontal shaft has a bearing installed at the cavity groove. The specimen to be processed is placed in the specimen groove and located on the top of the bearings on the two horizontal shafts. The specimen to be processed in the specimen groove is supported by the bearings. The horizontal shafts are fixed by bolts I on both sides of the lower mold, and the N cavity grooves are fixed together by bolts III.

[0010] The electric adjustable stress corrosion specimen preparation device has a specimen delivery mechanism located at the center of the bottom of the machine body, consisting of a specimen storage chamber and a specimen guide groove. The specimen slides along the sloping specimen guide groove into the specimen storage chamber.

[0011] The electric adjustable stress corrosion sample preparation device has a hydraulic system located in the hydraulic control cabinet, consisting of a hydraulic rod, an upper crossbeam, a hydraulic cylinder, and a pressure sensor. The upper crossbeam is fixed to the machine body and connected to the hydraulic cylinder on its lower side. One end of the hydraulic cylinder is connected to the hydraulic rod, which extends downward to connect to the upper mold. A pressure sensor is installed in the oil inlet pipe of the hydraulic cylinder to monitor the oil pressure in real time and transmit it to the controller via a line to adjust the operation of the hydraulic cylinder.

[0012] The electrically adjustable stress corrosion specimen preparation device is used to prepare either a U-shaped stress corrosion specimen or a C-shaped stress corrosion specimen.

[0013] The design concept of this utility model is:

[0014] In spent fuel reprocessing, some key equipment operates under the combined effects of nitric acid corrosion and stress, thus leading to stress corrosion. Stress corrosion testing is a crucial method for assessing the risk of brittle fracture in materials under the combined influence of stress and specific corrosive environments. Stress corrosion testing requires precise control of the bending stress and shape of the specimen. Traditional stress corrosion specimen preparation methods (such as manual bending and bolt fixing) suffer from inaccurate stress control and low preparation efficiency, which can affect test repeatability and efficiency due to specimen quality issues. Based on these existing engineering problems, this invention provides an electrically adjustable stress corrosion specimen preparation device. This device adopts a modular design, supports the preparation of various stress corrosion specimens, can precisely control the bending angle and stress magnitude, and features a specimen export mechanism and an automatic tightening system, making it suitable for the efficient preparation of specimens of different specifications.

[0015] The machine body must support the sample export mechanism, interchangeable mold assembly, hydraulic system, electrical control system, and automatic tightening system, and withstand bending and impact loads. The choice of machine body material directly affects the rigidity, corrosion resistance, service life, and operational safety of the equipment. High-strength structural steel is selected as the core of the frame, which has the advantages of high rigidity, moderate cost, and good machinability (easy to weld and machine, suitable for complex structural designs). Using high-rigidity steel can reduce elastic deformation and ensure the repeatability of U-shaped bending angle and stress control.

[0016] The connection between the hydraulic rod and the upper mold needs to meet the requirements of high rigidity, centering, and quick assembly and disassembly, while avoiding fatigue failure caused by stress concentration. The flange bolt connection method can meet the requirements of high rigidity, precise centering, and easy replacement of different upper molds. A spherical gasket is installed between the flange connections to compensate for the small angular deviation between the hydraulic rod and the upper mold. Lubricating grease should be applied to the gasket regularly.

[0017] To achieve mass production and high repeatability of samples, the design incorporates one or more parallelly spaced concave grooves in the lower mold of the interchangeable mold set, while the upper mold is equipped with a punch that matches the number of concave grooves, enabling the production of multiple samples in a single cycle.

[0018] To enable automatic export of samples after preparation, a sample export mechanism was designed. The lower mold is designed as a through mold with a through-hole forming cavity, which facilitates the sample falling off by its own weight after forming. A buffer guide groove is also provided to protect the sample from deformation.

[0019] This utility model has the following advantages and beneficial effects:

[0020] 1. The interchangeable mold assembly of this utility model has a wide range of applications and great design flexibility. It allows for the replacement of upper and lower molds of appropriate materials and models according to the different materials, shapes, and sizes of the required samples.

[0021] 2. This utility model adopts a modular design, and each part of the device can be easily disassembled, combined, and modified.

[0022] 3. The interchangeable mold assembly of this utility model has one or more concave mold slots arranged in parallel at intervals in the lower mold, and the upper mold is provided with a punch matching the number of concave mold slots, so as to realize the batch production of samples.

[0023] 4. This utility model combines a pressure sensor, a replaceable mold assembly, and an electronic control system to achieve sample manufacturing and high repeatability, thereby improving testing efficiency and data reliability.

[0024] 5. The automatic tightening system of this utility model uses an infrared rangefinder to ensure that the stress state of the sample meets the test requirements through real-time feedback.

[0025] 6. The electrically adjustable stress corrosion sample preparation device provided by this utility model achieves high-precision and high-efficiency sample preparation, and solves the problems of inaccurate stress control and cumbersome operation of traditional methods.

[0026] 7. This invention solves the problem that existing tools can only apply the same strain to samples by means of real-time feedback from a pressure sensor and accurate adjustment by an electronic control system. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of this utility model.

[0028] Figure 2 for Figure 1 A schematic diagram of the upper mold.

[0029] Figure 3 for Figure 1 A schematic diagram of the lower mold.

[0030] Figure 4 for Figure 1 Side view of the middle.

[0031] Figure 5 for Figure 1 A schematic diagram of the automatic tightening system.

[0032] Figure 6 for Figure 3 The lower mold section view.

[0033] In the diagram: 1. Body; 2. Base; 3. Sample storage chamber; 4. Sample guide groove; 5. Electrical control system; 6. T-shaped guide rail groove; 7. T-shaped guide rail slider; 8. Lower mold; 9. U-shaped die groove; 10. Bearing; 11. Bolt I; 12. Sample groove; 13. Upper mold; 14. Flange interface; 15. Flange I; 16. Spherical gasket; 17. Flange II; 18. Bolt II; 19. Hydraulic rod; 20. Hydraulic control cabinet; 21. Hydraulic system; 22. Bolt III; 23. Punch; 24. Lower mold positioning groove; 25. Movable worktable; 26. Lead screw; 27. Nut supply unit; 28. Infrared rangefinder; 29. ​​Bolt supply unit; 30. Horizontal shaft; 31. Guide rail; 32. Guide rail positioning groove; 33. Sample to be processed; 34. U-shaped stress corrosion sample; 35. Sample hole. Detailed Implementation

[0034] like Figures 1-6As shown, this utility model designs an electrically adjustable U-shaped stress corrosion sample preparation device. The device comprises a body 1, a sample delivery mechanism, a replaceable mold assembly, a hydraulic system 21, an electrical control system 5, and an automatic tightening system. The device mainly includes: a body 1, a base 2, a sample storage chamber 3, a sample guide groove 4, an electrical control system 5, a T-shaped guide rail groove 6, a T-shaped guide rail slider 7, a lower mold 8, a U-shaped concave mold groove 9, a bearing 10, bolt I 11, a sample groove 12, an upper mold 13, a flange interface 14, a flange I 15, a spherical gasket 16, a flange II 17, a bolt II 18, a hydraulic rod 19, a hydraulic control cabinet 20, a hydraulic system 21, a bolt III 22, a punch 23, a lower mold positioning groove 24, a movable worktable 25, a lead screw 26, a nut supply unit 27, an infrared rangefinder 28, a bolt supply unit 29, a horizontal shaft 30, a guide rail 31, and a guide rail positioning groove 32. The specific structure is as follows:

[0035] The bottom of the body 1 is equipped with a sample discharge mechanism, which includes a sample storage chamber 3 and a sample guide groove 4. The sample storage chamber 3 is connected to the sample guide groove 4 with a slope. The upper end of the sample guide groove 4 is equipped with a guide rail 31 that is parallel to each other. The lower mold 8 is engaged with the T-shaped guide groove 6 on the guide rail 31 through the T-shaped guide rail slider 7 on its upper end. An electrical control system 5 is installed above the sample discharge mechanism. The electrical control system 5 is located on one side of the lower mold 8 and the guide rail 31. The electrical control system 5 includes a motor and an electrical control box. Above the lower mold 8 is a hydraulic control cabinet 20 for installing the upper mold 13. The hydraulic control cabinet 20 is equipped with a hydraulic system 21. The hydraulic system 21 includes a hydraulic rod 19, an upper crossbeam, and a hydraulic cylinder. The hydraulic rod 19 extends downward. The flange II 17 at the lower end of the hydraulic rod 19 is aligned with the flange I 15 at the upper end of the upper mold 13 through bolts II 18 and is evenly tightened. A spherical gasket 16 is installed at the connection between the two flanges.

[0036] The body 1 adopts a C-shaped frame made of tool steel to reduce elastic deformation and ensure the repeatability of bending angle and stress control of U-shaped stress corrosion specimens; the base 2 is made of cast iron and other materials with high compressive strength and good stability. The base 2 and the body 1 are fixed by threaded holes and bolts pre-embedded in the bottom of the body; the top of the body 1 is equipped with a hydraulic control cabinet 20 to accommodate the hydraulic system 21.

[0037] The automatic tightening system is integrated into the side of the stamping station (with interchangeable mold sets) or a separate station (taking the side of the stamping station as an example). A torque sensor controls the tightening force, ensuring adjustable tightening. An infrared rangefinder or laser displacement sensor (taking infrared rangefinder as an example) is installed at the assembly station to measure the distance between the two arms of the stress corrosion specimen in real time and calculate the deflection value. The data is fed back to the electronic control system 5, which dynamically adjusts the tightening torque until the deflection reaches the preset standard. In this embodiment, an automatic tightening system is provided on one side of the guide rail 31. The automatic tightening system includes a movable worktable 25, a lead screw 26, a nut supply unit 27, an infrared rangefinder 28, and a bolt supply unit 29. A U-shaped stress corrosion sample 34 is placed on the movable worktable 25. Nut supply units 27 and bolt supply units 29 are respectively provided on both sides. An infrared rangefinder 28 is provided on the inner side of each nut supply unit 27 and bolt supply unit 29. The lead screw 26 is located at the lower end of the bolt supply unit 29 and corresponds to one end of the bolt output by the bolt supply unit 29. The lead screw 26 is connected to the electrical control system 5. The motor drives the lead screw 26 to push the bolt through the two sample holes 35 at the end of the U-shaped stress corrosion sample 34. The protruding end of the bolt is connected to the nut output by the nut supply unit 27.

[0038] The replaceable mold assembly consists of an upper mold 13 and a lower mold 8, made of tool steel. The upper mold 13 has a flange interface 14 on its top, which is fastened to flange I 15 by threads. Flange I 15 is evenly fastened to flange II 17 at the lower end of hydraulic rod 19 by bolts II 18 (threaded direct connection or quick-change slot connection can also be used, taking flange connection as an example). A spherical gasket 16 is installed at the flange connection. The lower mold 8 has T-shaped guide rail sliders 7 on both sides of its bottom (other shapes of guide rail sliders and guide rail grooves can also be selected, taking T-shape as an example). Each T-shaped guide rail slider 7 engages with the corresponding T-shaped guide rail groove 6 on the guide rail 31 in a sliding fit. The guide rail 31 must be made of ductile iron, and the T-shaped guide rail groove 6 on it must be coated with grease to reduce wear. A lower mold positioning groove 24 is set at the middle position of the top of the lower mold 8, which is aligned with the corresponding guide rail positioning groove 32 at the middle position on the guide rail 31 to ensure that the upper mold 13 and the lower mold 8 fit together. In addition, the lower mold 8 has one or more (five in this embodiment) U-shaped concave grooves 9 arranged in parallel at intervals, and the upper mold 13 is provided with punches 23 that match the position and number of the U-shaped concave grooves 9, so that multiple samples can be produced in a single cycle.

[0039] The sample delivery mechanism is located at the bottom center of the body 1 and consists of a sample storage chamber 3 and a sample guide groove 4. The sample storage chamber 3 is a cavity reserved during the manufacturing of the body 1. The sample slides along the sample guide groove 4 with a suitable slope to the sample storage chamber 3. There needs to be a certain distance between the upper end of the sample guide groove 4 and the lower end of the lower mold 8 so that the sample can fall smoothly and avoid deformation of the sample caused by excessive falling height. The sample storage chamber 3 can hold a certain number of U-shaped stress corrosion samples, reducing the frequency of manual sample removal.

[0040] The hydraulic system 21 is located in the hydraulic control cabinet 20 and consists of a hydraulic rod 19, an upper crossbeam, a hydraulic cylinder, and a pressure sensor. The upper crossbeam is fixed to the machine body 1 and connected to the hydraulic cylinder on its lower side. One end of the hydraulic cylinder is connected to the hydraulic rod 19, which extends downward to connect to the upper mold 13. A pressure sensor is installed in the oil inlet pipe of the hydraulic cylinder (the pressure sensor can also be set between the mold and the slider or at the force-bearing end of the hydraulic rod, taking the installation in the oil inlet pipe of the main hydraulic cylinder as an example). The oil pressure is monitored in real time and transmitted to the controller through the line to adjust the operation of the hydraulic cylinder.

[0041] The electrical control system 5 includes a motor and an electrical control box (PLC). The electrical control box is connected to the motor and the hydraulic system 21 via wires. The electrical control system 5 can independently control the stamping station and the automatic tensioning system.

[0042] like Figure 2 As shown, in the U-shaped stress corrosion specimen preparation device, the top of the upper mold 13 has a flange interface 14, the flange interface 14 is fastened to the flange I 15 by threads, the flange I 15 is evenly fastened to the flange II 17 at the lower end of the hydraulic rod 19 by bolts II 18, a spherical gasket 16 is installed at the flange connection, and the upper mold 13 is provided with a punch 23 that matches the position and number of the die groove 9.

[0043] like Figure 3 As shown, in the U-shaped stress corrosion specimen preparation device, the lower mold 8 is made of alloy steel, and its working surface has N U-shaped concave mold grooves 9 arranged equidistantly along the length direction. Each U-shaped concave mold groove 9 has a specimen groove 12 at its upper end, and two horizontal shafts 30 are provided below the specimen groove 12. Each horizontal shaft 30 has a bearing 10 installed at the U-shaped concave mold groove 9, supporting the specimen to be processed in the specimen groove 12. The horizontal shafts 30 are fixed by bolts I11 on both sides of the lower mold, and the N U-shaped concave mold grooves 9 are fixed together by bolts III22. T-shaped guide rail sliders 7 are provided on both sides of the bottom of the lower mold 8, engaging with the T-shaped guide rail grooves 6 on the machine body 1 in a sliding fit. A lower mold positioning groove 24 is provided at the middle position of the top of the lower mold 8, aligning with the corresponding groove at the middle position on the machine body 1 to ensure a proper fit between the upper and lower molds. The lower mold 8 has N (5 in this embodiment) U-shaped concave mold grooves 9 arranged in parallel at intervals, matching the upper mold 13, enabling the preparation of multiple specimens in a single cycle. The sample to be processed 33 is placed in the sample groove 12 and located on the top of the bearing 10 on the two horizontal shafts 30. During the process of the sample to be processed 33 being pressed down by the punch 23 of the lower die 8 to form a U-shaped stress corrosion sample, the rotation of the bearing can reduce the sliding friction when the sample to be processed is pressed down.

[0044] During sample preparation, the sample 33 (standard plate-shaped sample) to be processed is placed in the sample slot 12 of the lower mold 8. By operating the control box in the electrical control system 5, the hydraulic rod 19 is controlled to advance to the preset feed amount, so that the U-shaped stress corrosion sample is formed and falls off the lower mold 8, entering the sample storage chamber 3 below along the sample guide groove 4. During the process, the pressure sensor detects the pressure in real time, and the control box dynamically adjusts it. The hydraulic rod 19 is reset, and the single stamping is completed. A single stamping is a cycle. After a cycle is completed, the next batch of samples is placed in the sample slot 12 to realize the batch preparation of samples. After stamping, the stamped U-shaped stress corrosion sample 34 is taken out from the sample storage chamber 3 and accurately placed on the movable worktable 25 of the automatic tightening system next to the stamping station. The screw 26 is started to assemble and tighten the polytetrafluoroethylene stud and nut to both ends of the sample hole 35 of the U-shaped stress corrosion sample 34. The ends of the U-shaped stress corrosion sample 34 are connected by the matching stud and nut to prevent deformation from interfering with the corrosion test results.

[0045] The results show that this invention can prepare U-shaped stress corrosion test specimens of different quantities and models in batches by changing the upper and lower molds. It can also be used for the preparation of specimens of other shapes (such as C-shaped) of stainless steel, alloys and other materials. Combined with pressure sensors, interchangeable mold systems and automatic tightening systems, it can achieve automation and high repeatability, thereby improving testing efficiency and data reliability. It solves the problems of low efficiency, inaccurate stress control and poor batch consistency in the traditional preparation of U-shaped stress corrosion test specimens, especially for the stress corrosion testing needs of nitric acid corrosion environment in spent fuel reprocessing.

[0046] The above description is merely a preferred embodiment of this utility model and does not constitute any limitation on the present utility model. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive technical essence shall still fall within the protection scope of the present utility model.

Claims

1. An electrically adjustable stress corrosion specimen preparation device, characterized in that, The device comprises a main body, a sample delivery mechanism, a replaceable mold assembly, a hydraulic system, an electrical control system, and an automatic tightening system. The sample delivery mechanism is located at the bottom of the main body, while a hydraulic control cabinet housing the hydraulic system is located at the top. The sample storage chamber of the sample delivery mechanism is connected to a sloped sample guide groove. A guide rail is parallel to the upper end of the sample guide groove. The lower mold of the replaceable mold assembly engages with the guide rail groove on the guide rail via its upper guide rail slider. The electrical control system is installed above the sample delivery mechanism, located on one side of the lower mold and guide rail. Above the lower mold is a hydraulic control cabinet housing the upper mold of the replaceable mold assembly. The hydraulic control cabinet contains the hydraulic system, with hydraulic rods extending downwards. The lower end of the hydraulic rods corresponds to the upper end of the upper mold and is connected via a flange, threaded connection, or quick-change slot. The automatic tightening system is integrated to the side of the replaceable mold assembly or at a separate station. It connects the two sample holes at the end of the stress corrosion sample and uses an infrared rangefinder or laser displacement sensor to measure the distance between the two arms of the stress corrosion sample in real time.

2. The electrically adjustable stress corrosion specimen preparation apparatus according to claim 1, characterized in that, The automatic tightening system includes a movable worktable, a lead screw, a nut supply unit, an infrared rangefinder, and a bolt supply unit. The stress corrosion sample is placed on the movable worktable, and the nut supply unit and bolt supply unit are respectively set on both sides. An infrared rangefinder or laser displacement sensor is set inside each of the nut supply unit and bolt supply unit. The lead screw is located at the lower end of the bolt supply unit and corresponds to one end of the bolt output by the bolt supply unit. The lead screw is connected to the electrical control system, and the motor drives the lead screw to push the bolt through the two sample holes at the end of the stress corrosion sample. The protruding end of the bolt is connected to the nut output by the nut supply unit.

3. The electrically adjustable stress corrosion specimen preparation apparatus according to claim 1, characterized in that, The replaceable mold assembly consists of an upper mold and a lower mold. The upper mold has a flange interface on its top, which is fastened to flange I by threads. The flange II at the lower end of the hydraulic rod is connected to flange I at the upper end of the upper mold by bolts II and is evenly fastened. A spherical gasket is installed at the flange connection. The lower mold has T-shaped guide rail sliders on both sides of its bottom. Each T-shaped guide rail slider engages with the corresponding T-shaped guide rail groove on the guide rail in a sliding fit. A lower mold positioning groove is set at the middle position of the top of the lower mold, which is aligned with the corresponding guide rail positioning groove at the middle position on the guide rail to ensure that the upper mold and the lower mold fit together. The lower mold has one or more spaced and parallel concave mold grooves, and the upper mold has punches that match the position and number of the concave mold grooves.

4. The electrically adjustable stress corrosion specimen preparation apparatus according to claim 3, characterized in that, The lower die working surface has N die slots arranged at equal intervals along its length. Each die slot has a sample slot at its upper end. Two horizontal shafts are set below the sample slot. Each horizontal shaft has a bearing installed at the die slot. The sample to be processed is placed in the sample slot and is located on the top of the bearing on the two horizontal shafts. The sample to be processed in the sample slot is supported by the bearing. The horizontal shafts are fixed by bolts I on both sides of the lower die. The N die slots are fixed together by bolts III.

5. The electrically adjustable stress corrosion specimen preparation apparatus according to claim 1, characterized in that, The sample delivery mechanism is located at the center of the bottom of the machine body and consists of a sample storage chamber and a sample guide groove. The sample slides along the sloping sample guide groove to the sample storage chamber.

6. The electrically adjustable stress corrosion specimen preparation apparatus according to claim 1, characterized in that, The hydraulic system is located in the hydraulic control cabinet and consists of a hydraulic rod, an upper crossbeam, a hydraulic cylinder, and a pressure sensor. The upper crossbeam is fixed to the machine body and connected to the hydraulic cylinder on the lower side. One end of the hydraulic cylinder is connected to the hydraulic rod, which extends downward to connect to the upper mold. A pressure sensor is installed in the oil inlet pipe of the hydraulic cylinder to monitor the oil pressure in real time and transmit it to the controller through the line to adjust the operation of the hydraulic cylinder.

7. The electrically adjustable stress corrosion specimen preparation apparatus according to claim 1, characterized in that, The stress corrosion test specimens are either U-shaped or C-shaped.

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