A tensile system, a tensile stress corrosion test device and method

Abstract

The present application relates to a kind of tensile system, tensile stress corrosion test device and method, specifically a kind of scheme for being immersed in corrosive liquid and applying predetermined constant load to test piece, to test whether it breaks within specified time limit.A kind of tensile stress corrosion test device, by rack system, lever system, weight system, tensile system is composed.Rack system is the basic part of the whole tensile stress corrosion test device, and the rest lever system, weight system, tensile system etc.are installed on rack system.Lever system is the force value transmission and amplification part of tensile stress corrosion test device, and it acts together with weight system, accurately amplifies the force value of weight system after transmission to tensile system and finally loads on test piece.Tensile system is the working part of tensile stress corrosion test device, for the gravity of weight system is amplified through lever system and loaded on test piece, while providing corrosion liquid immersion environment for test piece.

Description

Technical Field

[0001] This invention relates to a tensile system, a tensile stress corrosion testing apparatus and method, specifically an apparatus for immersing a specimen in a corrosive liquid and applying a predetermined constant load (tensile force) to test whether it breaks within a specified time limit. Background Technology

[0002] In engineering applications, a large number of metal materials, mechanical parts or components work in corrosive environments while also bearing certain stresses (mainly tensile stresses). Under the combined effect of stress and corrosion, metal materials, mechanical parts or components may fail due to damage. Such failures are often sudden fractures without warning, which can cause great harm to equipment and personnel safety. Therefore, it is necessary to take great precautions.

[0003] To assess the ability of metallic materials, mechanical parts, or components to resist damage under the combined effects of stress and corrosion, and to verify their design and manufacturing processes, stress corrosion testing is required. Stress corrosion testing methods mainly include constant deformation testing, constant load testing, slow strain rate testing, and fracture mechanics (pre-crack) testing. Among these, constant load testing (primarily tensile load testing) is more widely used in engineering because it better simulates the working conditions of most engineering components, has more stringent testing conditions, and can test the stress corrosion resistance of components in a shorter time.

[0004] Constant load (mainly tensile load) tests need to be conducted on tensile stress corrosion testing equipment. Currently, most stress corrosion testing equipment on the market is multifunctional, combining multiple testing methods such as constant deformation, constant load, slow strain rate, and fracture mechanics (pre-crack). However, such equipment is complex in structure, large in size, expensive, and cumbersome to operate. After wear and tear, users cannot adjust the load accuracy or adjustment becomes extremely difficult. Furthermore, the weights are heavy, making it very strenuous for operators to move them, resulting in high labor intensity. Therefore, such equipment is not suitable for users who only require a single constant load tensile stress corrosion test. Summary of the Invention

[0005] The purpose of this invention is to design a simple, compact, inexpensive, easy-to-operate, highly accurate, and easily adjustable method for immersing standard samples of the test material in a corrosive liquid and applying a preset constant load (tensile force) to test whether the sample breaks within a specified time limit. This method solves the problems of existing constant load stress corrosion testing equipment, such as complex structure, large size, high cost, cumbersome operation, difficulty in adjusting load accuracy, and high labor intensity for operators.

[0006] This invention provides a tensile system, including an upper pull seat, an upper adjusting nut, an upper pull rod, a corrosive liquid cylinder, a sealing ring, a thin nut, a lower pull rod, an anti-tilt cap, a pin, a lower adjusting screw, a lower adjusting nut, a U-shaped retaining ring, and a lower pull seat. The upper pull seat is connected to the front end of a lever system. The upper end of the upper adjusting nut has a stepped hole structure with a reduced diameter on the outer side. The upper pull seat passes through the reduced diameter hole in the upper adjusting nut, and the lower stepped stop of the upper pull seat limits the movement of the upper stepped hole in the upper adjusting nut. The lower end of the upper adjusting nut has an internal thread that connects to the external thread of the large end of the upper pull rod. The small end of the upper pull rod has a threaded hole for connecting to the upper end of the test piece. The corrosive liquid cylinder has a large opening at the top and a small round hole at the bottom. The large end of the lower pull rod has a threaded hole for connecting to the lower end of the test piece. The lower end of the lower pull rod has a stepped shaft structure below it, and the large end of the lower pull rod is located inside the corrosive liquid cylinder. A sealing ring is placed below the large end of the lower pull rod on the bottom surface of the corrosive liquid cylinder. The stepped shaft passes through a small round hole below the corrosive liquid cylinder and is secured with a thin nut. The lower end of the pull rod has a radial through hole, and the upper end of the lower adjusting screw has a bowl-shaped structure with a radial through hole on its outer ring. The radial through holes of the pull rod and the lower adjusting screw are aligned, with a limiting pin passing through them, connecting the pull rod and the lower adjusting screw as a single unit. However, the pull rod and the lower adjusting screw can rotate relative to each other around the limiting pin. The upper end of the lower adjusting screw is covered with an anti-tilt cover, and the upper surface of the anti-tilt cover has a... The U-shaped groove can be adjusted to be parallel or perpendicular to the pin shaft by rotating the anti-tilt cover; the slender rod below the lower adjusting screw has threads that mate with the threaded hole of the lower adjusting nut and extend into the central through hole of the pull-down seat; the inner wall of the large hole below the lower adjusting nut has a square through groove that corresponds to the groove above the pull-down seat, and a U-shaped retaining ring is inserted into the groove to connect the lower adjusting nut and the pull-down seat as one unit; the outer wall of the lower adjusting nut has a slot for inserting the U-shaped retaining ring.

[0007] This invention provides a tensile stress corrosion testing apparatus, comprising a frame system, a lever system, a weight system, and a tensile system. The frame system is an overall U-shaped structure with an opening facing forward and an internal cavity. The lever system is installed through the upper cavity of the U-shaped structure, with its rotation fulcrum located within the cavity above the opening of the U-shaped structure. The front end of the lever system is connected to the tensile system, which extends downward through the opening of the U-shaped structure. The bottom of the tensile system is fixed to the bottom of the cavity below the opening of the U-shaped structure. The rear end of the lever system extends from the upper rear end of the cavity of the U-shaped structure and connects to the weight system. The tensile system includes an upper pull seat, an upper adjusting nut, an upper pull rod, a corrosive liquid cylinder, a sealing ring, a thin nut, a lower pull rod, an anti-tilt cap, a pin, a lower adjusting screw, a lower adjusting nut, a U-shaped retaining ring, and a lower pull seat. The upper pull seat is connected to the front end of the lever system. The upper adjusting nut has a stepped hole structure at its upper end, with the hole diameter decreasing towards the outer edge. The upper pull seat passes through the reduced-diameter hole in the upper adjusting nut, and the stepped stop at the lower end of the upper pull seat limits the movement of the stepped hole at the upper end of the upper adjusting nut. The lower end of the upper adjusting nut has an internal thread that connects to the external thread at the large end of the upper pull rod. The small end of the upper pull rod has a threaded hole for connecting to the upper end of the sample. The corrosive liquid cylinder has a large opening at its upper part. The bottom surface of the lower part has a small round hole. The large end of the pull rod has a threaded hole for connecting to the lower end of the sample. Below the large end of the pull rod is a stepped shaft structure. The large end of the pull rod is located inside the corrosion liquid cylinder. A sealing ring is placed below the large end of the pull rod on the bottom surface of the corrosion liquid cylinder. The stepped shaft of the pull rod passes through the small round hole below the corrosion liquid cylinder and is tightened with a thin nut. The lower end of the pull rod has a radial through hole. The upper end of the lower adjusting screw has a bowl-shaped structure with a radial through hole on its outer ring. The radial through hole of the pull rod is aligned with the radial through hole of the lower adjusting screw. A limiting pin passes through the screw, connecting the pull rod and the lower adjusting screw into one unit. The adjusting screw can rotate relative to the limiting pin. The upper end of the lower adjusting screw is covered with an anti-tilt cover. The upper surface of the anti-tilt cover has a U-shaped groove. By rotating the anti-tilt cover, the direction of the U-shaped groove can be adjusted to be parallel or perpendicular to the pin. The slender rod below the lower adjusting screw has threads that mate with the threaded hole of the lower adjusting nut and extend into the central through hole of the pull-down seat. The inner wall of the large hole below the lower adjusting nut has a square through groove that corresponds to the groove above the pull-down seat. A U-shaped retainer is inserted into the groove to connect the lower adjusting nut and the pull-down seat as one unit. The outer wall of the lower adjusting nut has a slot for inserting the U-shaped retainer. The bottom of the pull-down seat is fixed to the bottom of the frame system.

[0008] The frame system is the foundation of the entire tensile stress corrosion testing apparatus. Other components, such as the lever system, weight system, and tensile system, are all mounted on the frame system.

[0009] The tensile system is the working part of the tensile stress corrosion testing apparatus. It amplifies the weight of the weight system through a lever system and applies it to the specimen, while also providing an environment for immersing the specimen in the corrosive liquid. A sealing ring and a thin nut secure the pull rod to the corrosion liquid cylinder, ensuring a leak-proof seal. The anti-tilt cover serves the following functions: when the U-shaped groove of the anti-tilt cover is perpendicular to the limiting pin, the pull rod can rotate around the limiting pin on the lower adjusting screw, allowing the corrosion liquid cylinder to tilt at a certain angle for easy loading and unloading of the specimen. When the U-shaped groove of the anti-tilt cover is parallel to the limiting pin, the pull rod cannot rotate around the pin due to the obstruction of the straight edge of the U-shaped groove, preventing the corrosion liquid cylinder from tipping over if the specimen breaks. The U-shaped retaining ring allows the lower adjusting nut to rotate on the pull rod but not move axially. When the lower adjusting nut is rotated, its threaded hole interacts with the thread on the slender rod of the lower adjusting screw, allowing the lower adjusting screw to move up and down.

[0010] Furthermore, the lever system includes a lever, a lever support, needle roller bearings, a pin, a front lifting ring, a rear lifting ring, a bearing housing, bearing housing screws, a sliding weight, a pressure plate, and a pointer. The lever has two horizontal holes perpendicular to its direction of travel near the front end. Each hole contains a needle roller bearing, and each bearing contains a pin. A front lifting ring is attached to the pin in the first hole near the front end of the lever. The pin in the second hole near the front end of the lever is placed in a groove in the lever support and pressed down by the pressure plate. The lever support is installed inside the cavity above the U-shaped opening of the frame system. The pointer is fixed to the front end face of the lever. The lever is designed to indicate its horizontal position. A flat surface is milled at the rear end of the lever, on which a bearing seat is mounted via bearing seat screws. A needle roller bearing is installed in the bearing seat hole, and a pin is installed in the needle roller bearing. A rear lifting ring, located on the outer rear side of the frame system, is hung on the pin. The distance between the second hole at the front end of the lever and the bearing seat hole is m, and the distance between the two holes at the front end of the lever is n. The ratio of these two distances constitutes the lever's magnification ratio of m:n. The rider is located on the lever. Threaded holes are opened at the bottom of both the front and rear lifting rings. The upper pull seat is threadedly connected to the lower part of the front lifting ring, and the weight system is hung below the rear lifting ring. The frame system has an indicator window with scale lines corresponding to the pointer.

[0011] The lever system is the force transmission and amplification part of the tensile stress corrosion testing apparatus. Working in conjunction with the weight system, it precisely amplifies the force value of the weight system before transmitting it to the tensile system and finally applying it to the specimen. The ratio of the distance between the second hole at the lever's front end and the bearing seat hole to the distance between the two holes at the lever's front end constitutes the lever system's amplification ratio. This ratio amplifies the force value of the weight system, allowing for a larger tensile force with fewer weights. The bearing seat is fixed to the lever with bearing seat screws, allowing its position on the lever to be adjusted. This adjustment precisely adjusts the lever amplification ratio, compensating for errors in the lever amplification ratio caused by hole machining, thus improving the overall force accuracy of the tensile stress corrosion testing apparatus while significantly reducing the difficulty and cost of component machining. During operation, the lever system requires it to be in a horizontal position, which can be determined by observing the pointer's indication.

[0012] Furthermore, the weight system includes a weight hanging rod, a weight hanging pan, and weights of various force values; the upper end of the weight hanging rod is threaded and connects to the threaded hole on the rear lifting ring, and the lower end of the weight hanging rod is also threaded and connects to the threaded hole in the center of the weight hanging pan.

[0013] The weights, including large ones such as 1000N, 500N, 200N, 100N, and 50N, adopt a C-shaped opening design, while the smaller ones such as 20N, 10N, 2N, and 1N adopt a cylindrical one-piece design. All weights are equipped with adjustment holes, which are sealed with nuts. The force value of the weights can be precisely adjusted by adding lead blocks into the adjustment holes and weighing them with a precision balance.

[0014] The weight system is the force loading part of the tensile stress corrosion testing apparatus, used to apply a preset force to the test specimen. The weight rod, weight pan, and the lever itself serve as the basic force value, and its accuracy is precisely adjusted by changing the position of the rider on the lever.

[0015] Furthermore, the main frame of the rack system includes a base plate, a left side plate and a right side plate with U-shaped openings facing forward, installed on both sides of the base plate. A semi-circular support rod is connected between the front and rear ends of the top of each of the left and right side plates. A base panel is vertically installed between the lower front ends of the U-shaped openings of the left and right side plates. A first horizontal cover plate is horizontally installed at the top of the lower U-shaped openings of the left and right side plates. A front cover plate is vertically installed between the U-shaped openings of the left and right side plates. A pointer panel is installed between the upper front ends of the U-shaped openings of the left and right side plates. A second horizontal cover plate is horizontally installed between the upper bottom ends of the U-shaped openings of the left and right side plates. A top cover plate is installed between the two semi-circular support rods and the tops of the left and right side plates. A rear cover plate is installed between the rear ends of the left and right side plates, forming a closed shell-like structure for the entire rack system. Four adjustable feet are installed below the base plate. The pointer panel has a pointer window with scale lines. The pointer is L-shaped and corresponds to the pointer window; the rear cover plate has an upward-opening groove near the top; a lower limit plate is installed in the middle of the left and right side plates near the rear cover plate, part of which is located inside the housing and below the lever, and part of which extends through the groove on the rear cover plate to the outside of the housing; the lever support is installed between the upper front part of the U-shaped opening on the left and right side plates; the rear end of the lever passes through the groove on the rear cover plate and is limited between the semi-circular support rod and the lower limit plate; the extended part of the lower limit plate is connected to a lever lifting screw that runs vertically and is located below the lever; the second horizontal cover plate has a hole through which the upper pull seat passes and is threaded to the bottom of the front lifting ring; the first horizontal cover plate has a center hole through which the lower pull seat passes; a stepped through hole is made on the flange below the lower pull seat, and the flange is fastened to the base plate with screws; a level is installed on the first horizontal cover plate.

[0016] The level of the frame system can be adjusted by adjusting the adjustable feet. During the leveling process, a level instrument mounted on the leveling cover can be used to observe and assist in the leveling adjustment. A lower limit plate (for the lower limit of the lever) is installed at the upper rear of the frame system. It works together with the semi-circular support rod at the rear of the frame system (for the upper limit of the lever) to limit the vertical movement range of the lever. A lever lifting screw is provided on the lower limit plate. The lever lifting screw is located directly below the lever and is used to raise and release the rear end of the lever. When adding weights, raising the rear end of the lever relieves the tension of its front end system. After the weights are added, releasing the rear end of the lever allows the front end system to bear the predetermined tension under the action of the weight system, entering the working state.

[0017] The present invention provides a tensile stress corrosion test method: the method includes the following steps: S1, check the level instrument to see if the bubble is in the center of the level instrument. If it is not in the center, adjust the tensile stress corrosion test device to a horizontal state by adjusting the adjustable support feet. S2. Rotate the lever lifting screw to lift the rear end of the lever, so that the tensioning system is not subjected to tension. S3. Rotate the anti-tilt cover and adjust the direction of its U-shaped groove to be perpendicular to the limit pin. At this time, the corrosion liquid cylinder and pull rod assembly can be rotated around the limit pin to tilt the corrosion liquid cylinder at a certain angle. The cylinder opening rotates to face the operator so that one end of the sample piece with threads at both ends can be screwed into the threaded hole of the pull rod. S4. Unscrew the upper pull rod from the upper adjusting nut and remove it. Then screw the threaded hole of the upper pull rod into the other end of the test piece. S5. Rotate the connected pull rod, corrosion liquid cylinder, sample piece, and upper pull rod together around the limiting pin to a vertical position, screw the external thread of the upper pull rod into the internal thread of the upper adjusting nut and lock it. S6. Rotate the anti-tilt cover and adjust the direction of its U-shaped groove to be parallel to the limit pin shaft to ensure that after the sample is pulled apart, the corrosion liquid cylinder and pull rod assembly will not rotate around the limit pin shaft, thus preventing the corrosion liquid from spilling out and causing harm. S7. Pour the specified ratio of the etching solution into the etching solution cylinder, ensuring that the etching solution covers the specified area of ​​the sample. S8. Place the weights with the required force value smoothly on the weight plate; S9. Rotate the lever lifting screw in the opposite direction to lower the rear end of the lever, so that the sample is subjected to the set force under the combined action of the weight system and the lever system. At this time, observe the position of the pointer on the pointer panel to determine whether the lever is in a horizontal position. If the lever is not in a horizontal position, the level of the lever can be adjusted by adjusting the lower adjusting nut. S10. After a specified period of observation, observe whether the test specimen is broken under the combined action of corrosion and tensile force. If the test specimen is not broken within the specified time, it is deemed to be qualified; otherwise, it is deemed to be unqualified.

[0018] The beneficial effects of the apparatus and method described in this invention are as follows: (1) The fulcrum and force loading point of the lever are both made of cylindrical needle roller bearings, which abandons the traditional knife-edge bearing method, greatly simplifies the lever processing technology, reduces the processing difficulty, and at the same time greatly improves the service life of the lever and reduces the maintenance cost.

[0019] (2) By adopting a large lever ratio (such as m:n=20:1), the overall size of the test device is greatly reduced, and the weight of the weights is greatly reduced while generating the same force value, thus reducing the labor intensity of personnel.

[0020] (3) The lever ratio and the mass of the weights are both precisely adjustable. With the adjustment of the rider, the final loading force value can be precisely adjusted, and the overall force value accuracy of the test device is extremely high.

[0021] (4) An anti-tilting structure was designed. By rotating the anti-tilting cover, the direction can be changed, which can not only facilitate the installation of the test specimen and improve the efficiency of the test specimen installation, but also prevent the spillage of corrosive liquid during operation, thus ensuring the safety of equipment and operators. Attached Figure Description

[0022] Figure 1 A three-dimensional diagram of the tensile stress corrosion testing apparatus; Figure 2 A 3D view of the tensile stress corrosion testing apparatus (with the right side plate and top cover plate hidden). Figure 3 Side view of the tensile stress corrosion testing apparatus (right side panel hidden); Figure 4 A 3D diagram of rack system A; Figure 5 A 3D view of rack system A (with the right side panel and top cover hidden); Figure 6 A 3D view of rack system A (rear side view); Figure 7 A three-dimensional diagram of the lever system (B). Figure 8 A 3D diagram of the lever system (with the lever supports and other parts hidden); Figure 9 Schematic diagram of pin and lever support installation (one pressure plate is omitted); Figure 10 A 3D diagram of the weight system; Figure 11 A three-dimensional diagram of the stretching system; Figure 12 A three-dimensional view (section view) of the stretching system. Figure 13 A 3D diagram of the anti-tipping structure (tilting state); Figure 14 A 3D diagram of the anti-tilting structure (in an upright position); Figure 15 This is a 3D diagram of the anti-tilting structure (anti-tilting state).

[0023] In the picture: A—Frame system, B—Lever system, C—Weight system, D—Tension system; A1—Base plate, A2—Left side plate, A3—Right side plate, A4—Adjustable support foot, A5—Semi-circular support rod, A6—Base panel, A7—First horizontal cover plate, A8—Front cover plate, A9—Pointer panel, A10—Top cover plate, A11—Rear cover plate, A12—Lower limit plate, A13—Lever lifting screw, A14—Level instrument, A15—Second horizontal cover plate; B1 - Lever, B2 - Lever support, B3 - Needle roller bearing, B4 - Pin shaft, B5 - Front lifting ring, B6 - Rear lifting ring, B7 - Bearing block, B8 - Bearing block screw, B9 - Rider, B10 - Pressure plate, B11 - Pointer; C1 - Weight hanging rod, C2 - Weight hanging tray, C3 - Weight; D1 - Upper pull seat, D2 - Upper adjusting nut, D3 - Upper pull rod, D4 - Corrosion liquid cylinder, D5 - Sealing ring, D6 - Thin nut, D7 - Lower pull rod, D8 - Anti - tilt cover, D9 - Limit pin shaft, D10 - Lower adjusting screw, D11 - Lower adjusting nut, D12 - U - shaped retaining ring, D13 - Lower pull seat, D14 - Screw. Specific implementation manners

[0024] In order to make the purpose, technical solutions and advantages of this application clearer, the following further elaborates on this application in combination with the attached drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0025] The tensile stress corrosion test device requires a maximum tensile force value of 6 kN (basic force value of 1 kN), and the force value accuracy is ±1% F.S. The test requirements are as follows: For a specimen with a middle section diameter of 5 mm and threaded ends at both ends, the middle section is immersed in 5% salt water as the corrosion medium. Under the action of a constant tensile force of 5 kN, if it does not break within 60 days, it is considered qualified.

[0026] As Figure 1-3 shown, the tensile stress corrosion test device includes several major parts such as a frame system A, a lever system B, a weight system C, and a tensile system D.

[0027] The frame system A is the basic part of the entire tensile stress corrosion test device, and the remaining parts such as the lever system B, the weight system C, and the tensile system D are all installed on the frame system A. As Figure 4-6As shown, the main frame of the rack system A is assembled with screws from a base plate A1, a left side plate A2, a right side plate A3, and two semi-circular support rods A5. The main frame is fitted with a base panel A6, a first horizontal cover plate A7, a front cover plate A8, a pointer panel A9, a top cover plate A10, a rear cover plate A11, and a second horizontal cover plate A15, forming a closed shell structure for the entire rack system A. The U-shaped openings of the left side plate A2 and the right side plate A3 face forward, indicating they are towards the operator; therefore, the orientation of the left and right side plates is defined according to the operator's angle. Four adjustable feet A4 are mounted on the base plate A1. Adjusting the adjustable feet A4 allows for leveling the rack system A. During leveling, the level instrument A14 mounted on the horizontal cover plate A7 can be observed. When the bubble in the level instrument A14 enters the center circle of the level instrument A14, it indicates that the rack system A has been leveled. A lower limit plate A12 (used for the lower limit of lever B1) is installed at the upper rear of frame system A. It works in conjunction with the semi-circular support rod A5 (used for the upper limit of lever B1) at the rear of frame system A to limit the vertical movement range of the lever. A lever lifting screw A13 is provided on the lower limit plate A12, located directly below lever B1. The lever lifting screw A13 is used to lift and release the rear end of lever B1. When adding weight C3, the rear end of lever B1 is lifted so that its front end tension system D is not subjected to tensile force. After weight C3 is added, the rear end of the lever is released, allowing its front end tension system D to bear the predetermined tensile force under the action of weight system C, thus entering the working state.

[0028] Lever system B is the force transmission and amplification part of the tensile stress corrosion testing apparatus. It works in conjunction with the weight system C to precisely amplify the force value of the weight system C and transmit it to the tensile system D, which ultimately applies it to the specimen. For example... Figure 7 , 8As shown in Figure 9, lever system B consists of lever B1, lever support B2, needle roller bearing B3, pin B4, front lifting ring B5, rear lifting ring B6, bearing housing B7, bearing housing screw B8, sliding weight B9, pressure plate B10, and pointer B11. Lever B1 has two holes at its front end, in which needle roller bearing B3 is installed. Pin B4 is installed in needle roller bearing B3, and the front lifting ring B5 is hung on pin B4. Lever B1 has a milled flat surface at its rear end, on which bearing housing B7 is installed. Needle roller bearing B3 is installed in the hole of bearing housing B7, and pin B4 is installed in needle roller bearing B3. The rear lifting ring B6 is hung on pin B4. The distance between the second hole at the front end of lever B1 and the bearing seat hole is 420mm, and the distance between the two holes at the front end of lever B1 is 21mm. The ratio of these two distances constitutes a 20:1 amplification ratio for lever B1, used to amplify the force value of the weight system C, allowing for a larger tensile force with fewer weights. Bearing seat B7 is fixed to the lever with bearing seat screws B8, allowing adjustment of its position on lever B1. This precise adjustment of the lever amplification ratio compensates for errors in the lever amplification ratio caused by hole machining, improving the overall force accuracy of the tensile stress corrosion testing device while significantly reducing the difficulty and cost of parts machining. When lever system B is working, lever B1 should be in a horizontal position. This can be determined by observing the position of pointer B11 on pointer panel A9. Figure 9 As can be seen, the lever support B2 has a through groove in the middle to accommodate the lever B1. Grooves for placing the pin B4 are located on both sides of the through groove. The pin B4 on the lever B1 is placed in the left and right grooves of the lever support B2, and is held in place by a pair of pressure plates B10, preventing the pin B4 from rotating, moving axially, or falling out. The pressure plates B10 are mounted on the lever support B2 with screws (one of the pressure plates is hidden for easier viewing).

[0029] The weight system C is the force loading part of the tensile stress corrosion testing apparatus, used to apply a preset force value to the test specimen. For example... Figure 10As shown, the weight system C consists of a weight hanging rod C1, a weight hanging pan C2, and weights C3 of various force values. The upper end of the weight hanging rod C1 is threaded and connects to the threaded hole on the rear lifting ring B6. The lower end of the weight hanging rod C1 is also threaded and connects to the threaded hole in the center of the weight hanging pan C2. The weights C3 are available in various force values, including 1000N, 500N, 200N, 100N, 50N, 20N, 10N, 2N, and 1N, with several of each value. By combining weights of different values, any force value with a resolution of 1N between 1N and 6000N can be obtained. The larger weights C3, such as 1000N, 500N, 200N, 100N, and 50N, feature a C-shaped opening design, while the smaller weights C3, such as 20N, 10N, 2N, and 1N, feature a cylindrical, integrated design. All weights C3 have adjustment holes sealed with nuts. The force value of the weight C3 can be precisely adjusted by adding counterweights such as lead blocks into the adjustment holes and weighing it with a precision balance (the mass measured by the balance is multiplied by the local gravitational acceleration value; the nominal mass value of the weight is the nominal force value divided by the local gravitational acceleration value and then divided by the leverage ratio of 20. For example, the nominal mass of a weight with a nominal force value of 1000N is 1000÷9.7957÷20=5.10428kg). The weight of the weight rod C1, the weight pan C2, and the lever B1 itself serves as the base force value (1000N). Its accuracy is precisely adjusted by changing the position of the rider B9 on the lever B1. During adjustment, a standard force gauge is installed in the tension system D, and the position of the rider B9 on the lever B1 is adjusted back and forth until the standard force gauge indicates a value of 1000N.

[0030] Tensile system D is the working part of the tensile stress corrosion testing apparatus. It amplifies the weight of the weight system C by 20 times through the lever system B and applies it to the specimen, while also providing an environment for immersion in corrosive liquid. For example... Figure 11 , 12As shown, the tensile system D consists of an upper pull seat D1, an upper adjusting nut D2, an upper pull rod D3, a corrosive liquid cylinder D4, a sealing ring D5, a thin nut D6, a lower pull rod D7, an anti-tilt cover D8, a limiting pin D9, a lower adjusting screw D10, a lower adjusting nut D11, a U-shaped retaining ring D12, a lower pull seat D13, and a screw D14. The upper pull seat D1 has a threaded upper end that connects to the threaded hole on the front lifting ring B5. The upper adjusting nut D2 has a stepped hole structure at its upper end, with the outer hole diameter being smaller. The upper pull seat D1 passes through the smaller diameter hole in the upper adjusting nut D2, and its lower stepped stop interacts with the stepped hole at the upper end of the upper adjusting nut D2 to prevent the upper pull seat D1 from dislodging from the upper adjusting nut D2. The other end of the upper adjusting nut D2 has an internal thread that connects to the external thread at the large end of the upper pull rod D3. The small end of the upper pull rod D3 has a threaded hole for connection to the test piece. The pull rod D7 has a threaded hole at its large end for connection to the sample. A sealing ring D5 is placed below the stepped shaft at the large end of the pull rod D7. After passing through the circular hole below the corrosion liquid cylinder D4, it is tightened with a thin nut D6 to secure the pull rod D7 and the corrosion liquid cylinder D4 together, ensuring a leak-proof seal. The lower end of the pull rod D7 has a radial through hole. The upper end of the lower adjusting screw D10 has a bowl-shaped structure with a radial through hole on its outer ring. The radial through holes of the pull rod D7 and the lower adjusting screw D10 are aligned, with a limiting pin D9 passing through them, connecting the pull rod D7 and the lower adjusting screw D10 together. However, the pull rod D7 and the lower adjusting screw D10 can rotate relative to each other around the limiting pin D9. The upper end of the lower adjusting screw D10 is covered with an anti-tilt cover D8, which has a U-shaped groove on its upper surface. By rotating the anti-tilt cover D8, the... Adjust the direction of the U-shaped groove on the anti-tilt cover D8 to be parallel or perpendicular to the limiting pin D9. When the direction of the U-shaped groove on the anti-tilt cover D8 is perpendicular to the limiting pin D9, the pull rod D7 can rotate around the limiting pin D9 on the lower adjusting screw D10, so that the corrosion liquid cylinder D4 can be tilted at a certain angle to facilitate the loading and unloading of the sample. When the direction of the U-shaped groove on the anti-tilt cover D8 is parallel to the limiting pin D9, the pull rod D7 cannot rotate around the limiting pin D9 due to the obstruction of the straight edge of the U-shaped groove, which plays a role in preventing the corrosion liquid cylinder D4 from tipping over after the sample is pulled apart. The slender rod below the lower adjusting screw D10 has threads that mate with the threaded hole of the lower adjusting nut D11. The inner wall of the large hole below the lower adjusting nut D11 has a square through groove that corresponds to the groove above the pull-down seat D13. Inserting a U-shaped retainer D12 allows the lower adjusting nut D11 and the pull-down seat D13 to be connected as one unit, enabling the lower adjusting nut D11 to rotate on the pull-down seat D13 but not move axially. When the lower adjusting nut D11 is rotated, its threaded hole interacts with the threads on the slender rod of the lower adjusting screw D10, allowing the lower adjusting screw D10 to move up and down. The flange below the pull-down seat D13 has a stepped through hole, which can be fastened to the base plate A1 with screw D14.

[0031] The lever support B2 and the lower limit plate A12 are respectively embedded in the corresponding prefabricated grooves on the side walls of the left and right plates. When the device is working, the downward force on the lever support B2 and the lower limit plate A12 is shared by the left and right plates. The screws at both ends of the lever support B2 and the lower limit plate A12 only serve a connecting function and do not bear shear force, thereby reducing the screw size and greatly improving the system reliability.

[0032] Working process of the tensile stress corrosion testing apparatus: S1. Check the level A14 to see if the bubble is in the center of the level A14. If it is not in the center, adjust the adjustable support A4 to adjust the tensile stress corrosion test device to a horizontal state.

[0033] S2, rotate lever lifting screw A13, lift the rear end of lever B1, so that the tension system D is not subjected to tension.

[0034] S3. Rotate the anti-tilt cover D8, adjusting the direction of its U-shaped groove to be perpendicular to the limiting pin D9. At this time, the corrosive liquid cylinder D4 and the pull rod D7 can be rotated around the limiting pin D9 (as shown). Figure 13 As shown, tilt the corrosion liquid cylinder D4 at a certain angle and rotate the cylinder opening towards the operator so that one end of the sample (with threads at both ends) can be screwed into the threaded hole of the pull rod D7.

[0035] S4. Unscrew the upper pull rod D3 from the upper adjusting nut D2 and remove it. Then screw the threaded hole of the upper pull rod D3 into the other end of the test piece.

[0036] S5. Rotate the connected pull rod D7, corrosion liquid cylinder D4, sample piece, and pull rod D3 together around the limiting pin D9 until they are in a vertical position (e.g., Figure 14 As shown), screw the external thread of the upper pull rod D3 into the internal thread of the upper adjusting nut D2 and tighten it. During the operation of steps S3-S5, the lower adjusting screw D10 can be raised and lowered by adjusting the lower adjusting nut D11, which in turn raises and lowers the lower pull rod D7, the corrosion liquid cylinder D4, the test piece, the upper pull rod D3, etc. as a whole to facilitate the installation of the test piece.

[0037] S6. Rotate the anti-tilt cover D8 and adjust the direction of its upper U-shaped groove to be parallel to the limit pin D9 (e.g., ...). Figure 15 As shown in the figure, ensure that after the sample is broken, the combination of the corrosion liquid cylinder D4 and the pull rod D7 will not rotate around the limit pin D9, so as to prevent the corrosion liquid from spilling out and causing harm.

[0038] S7. Pour the prepared 5% saline corrosion solution into the corrosion solution cylinder D4, ensuring the corrosion solution covers the designated area of ​​the sample.

[0039] S8. Place the weight C3 with a combined force of 4kN stably on the weight plate C2 (the combined force of the 4kN weight and the 1kN basic force is 5kN test force).

[0040] S9. Rotate the lever lifting screw A13 in the opposite direction to lower the rear end of lever B1, so that the sample is subjected to a tensile force of 5kN under the combined action of the weight system C and the lever system B. At this time, observe the position of the pointer B11 on the pointer panel A9 to determine whether lever B1 is in a horizontal position. If lever B1 is not in a horizontal position, the level of lever B1 can be adjusted by adjusting the adjusting nut D11.

[0041] S10. After 60 days of observation, observe whether the test specimen is broken under the combined action of corrosion and tensile force. If the test specimen is not broken within 60 days, it is deemed to be qualified; otherwise, it is deemed to be unqualified.

Claims

1. A tensile stress corrosion testing apparatus, characterized in that, The system includes a frame system (A), a lever system (B), a weight system (C), and a tensioning system (D). The frame system (A) is a U-shaped structure with an opening facing forward and an internal cavity. The lever system (B) is installed through the upper cavity of the U-shaped structure, with its rotation fulcrum located in the cavity above the opening of the U-shaped structure. The front end of the lever system (B) is connected to the tensioning system (D), which passes through the opening of the U-shaped structure from top to bottom. The bottom of the tensioning system (D) is fixed to the bottom of the cavity below the opening of the U-shaped structure. The rear end of the lever system (B) extends from the upper rear end of the cavity of the U-shaped structure and connects to the weight system (C). D) includes an upper pull seat (D1), an upper adjusting nut (D2), an upper pull rod (D3), a corrosive liquid cylinder (D4), a sealing ring (D5), a thin nut (D6), a lower pull rod (D7), an anti-tilt cover (D8), a limiting pin (D9), a lower adjusting screw (D10), a lower adjusting nut (D11), a U-shaped retaining ring (D12), and a lower pull seat (D13); the upper pull seat (D1) is connected to the front end of the lever system (B); the upper end of the upper adjusting nut (D2) has a stepped hole structure with a smaller diameter on the outer side, the upper pull seat (D1) passes through the smaller diameter hole on the upper adjusting nut (D2), and the stepped stop below the upper pull seat (D1) limits the upper step hole of the upper adjusting nut (D2); the upper adjusting screw... The lower end of the female rod (D2) has an internal thread, which connects to the external thread of the large end of the upper pull rod (D3); the small end of the upper pull rod (D3) has a threaded hole for connecting to the upper end of the sample; the upper part of the corrosion liquid cylinder (D4) has a large opening, and the lower bottom surface has a small round hole; the large end of the lower pull rod (D7) has a threaded hole for connecting to the lower end of the sample; the lower end of the lower pull rod (D7) has a stepped shaft structure below it, and the large end of the lower pull rod (D7) is located inside the corrosion liquid cylinder (D4); a sealing ring (D5) is placed below the large end of the lower pull rod (D7) on the inner bottom surface of the corrosion liquid cylinder (D4); the stepped shaft of the lower pull rod (D7) passes through the small round hole below the corrosion liquid cylinder (D4) and is tightened with a thin nut (D6); the lower end of the lower pull rod (D7) has... It has a radial through hole. The upper end of the lower adjusting screw (D10) has a bowl-shaped structure with a radial through hole on its outer ring. The radial through hole of the pull rod (D7) is aligned with the radial through hole of the lower adjusting screw (D10). The limiting pin (D9) passes through it, connecting the pull rod (D7) and the lower adjusting screw (D10) into one piece. However, the pull rod (D7) and the lower adjusting screw (D10) can rotate relative to each other around the limiting pin (D9). The upper end of the lower adjusting screw (D10) is covered with an anti-tilt cover (D8). The upper surface of the anti-tilt cover (D8) has a U-shaped groove. The slender rod below the lower adjusting screw (D10) has a thread, which mates with the threaded hole of the lower adjusting nut (D11) and extends into the central through hole of the pull seat (D13).The inner wall of the large hole below the lower adjusting nut (D11) has a square through groove, which corresponds to the groove above the pull-down seat (D13). A U-shaped retaining ring (D12) is inserted into the groove to connect the lower adjusting nut (D11) and the pull-down seat (D13) into one piece. The outer wall of the lower adjusting nut (D11) has a socket for inserting the U-shaped retaining ring (D12). The bottom of the pull-down seat (D13) is fixed to the bottom of the frame system (A). The lever system (B) includes a lever (B1), a lever support (B2), a needle roller bearing (B3), a pin (B4), a front lifting ring (B5), a rear lifting ring (B6), a bearing housing (B7), a bearing housing screw (B8), a sliding weight (B9), a pressure plate (B10), and a pointer (B11). The lever (B1) has two horizontal holes near its front end, perpendicular to its direction. A needle roller bearing (B3) is installed in each hole, and a pin (B4) is installed in each of the needle roller bearings (B3). A front lifting ring (B5) is attached to the pin (B4) in the first hole near the front end of the lever (B1). The pin (B4) in the second hole near the front end of the lever (B1) is placed in a groove in the lever support (B2) and pressed down by the pressure plate (B10). The lever support (B2) is installed inside the cavity above the opening of the U-shaped structure of the frame system. The pointer (B11) A bearing seat (B7) is fixed to the front end of the lever (B1) to indicate the horizontal state of the lever (B1). The rear end of the lever (B1) has a milled flat surface, on which a bearing seat (B7) is installed by a bearing seat screw (B8). A needle roller bearing (B3) is installed in the hole of the bearing seat (B7), and a pin (B4) is installed in the needle roller bearing (B3). A rear lifting ring (B6) located on the rear outside of the frame system (A) is hung on the pin (B4). The distance between the second hole at the front end of the lever (B1) and the hole of the bearing seat is m, and the distance between the two holes at the front end of the lever (B1) is n. The ratio of the two constitutes the magnification ratio of the lever (B1) as m:n. The rider (B9) is located on the lever (B1). Both the front and rear lifting rings have threaded holes at the bottom. The pull-up seat (D1) is connected to the lower part of the front lifting ring (B5) by thread. The weight system (C) is hung below the rear lifting ring (B6). The frame system (A) has an indicator window corresponding to the pointer (B11).

2. The tensile stress corrosion testing apparatus as described in claim 1, characterized in that, The weight system (C) includes a weight hanging rod (C1), a weight hanging pan (C2), and weights of various force values ​​(C3). The upper end of the weight hanging rod (C1) is threaded and connects to the threaded hole on the rear lifting ring (B6). The lower end of the weight hanging rod (C1) is also threaded and connects to the threaded hole in the center of the weight hanging pan (C2).

3. The tensile stress corrosion testing apparatus as described in claim 2, characterized in that, The weights (C3) of 1000N, 500N, 200N, 100N and 50N are designed with a C-shaped opening, while the weights (C3) of 20N, 10N, 2N and 1N are designed with a cylindrical one-piece shape. All weights (C3) are equipped with adjustment holes, which are sealed with nuts. The force value of the weights (C3) can be precisely adjusted by adding lead blocks into the adjustment holes and weighing them with a precision balance.

4. A tensile stress corrosion testing apparatus as described in any one of claims 1-3, characterized in that, The main frame of the rack system (A) includes a base plate (A1), a left side plate (A2) and a right side plate (A3) with U-shaped openings facing forward, installed on both sides of the base plate (A1). A semi-circular support rod (A5) is connected between the front and rear ends of the top of the left and right side plates. A base panel (A6) is vertically installed between the lower front ends of the U-shaped openings of the left and right side plates. A first horizontal cover plate (A7) is horizontally installed at the top of the lower part of the U-shaped openings of the left and right side plates. A front cover plate (A8) is vertically installed between the U-shaped openings of the left and right side plates. A pointer panel (A9) is installed between the upper bottom of the U-shaped openings on the left and right side panels. A second horizontal cover plate (A15) is horizontally installed between the two semi-circular support rods (A5) and the top of the left and right side panels. A rear cover plate (A11) is installed between the rear ends of the left and right side panels, forming a closed shell structure for the entire frame system (A). Four adjustable feet (A4) are installed below the base plate (A1). The pointer panel (A9) has a pointer window with scale lines, and the pointer (B11) is L-shaped and the pointer window is aligned with the pointer. The openings correspond; a slot with an upward opening is opened near the top of the rear cover plate (A11). A lower limiting plate (A12) is installed in the middle of the left and right side plates near the rear cover plate (A11). Part of the lower limiting plate (A12) is located inside the housing and below the lever (B1), and part of it extends through the slot on the rear cover plate (A11) to the outside of the housing. The lever support (B2) is installed between the upper front part of the U-shaped opening on the left and right side plates. The rear end of the lever (B1) passes through the slot on the rear cover plate (A11) and is limited by the semi-circular support rod (A5) and the lower limiting plate (A12). Between; the lower limit plate (A12) has a lever lifting screw (A13) that extends vertically and is located below the lever (B1); the second horizontal cover plate (A15) has a hole through which the upper pull seat (D1) passes and is threaded to the bottom of the front lifting ring (B5); the first horizontal cover plate (A7) has a center hole through which the lower pull seat (D13) passes; the flange below the lower pull seat (D13) has a stepped through hole, and the flange is fastened to the base plate (A1) with screws (D14); the first horizontal cover plate (A7) is equipped with a level (A14).

5. The tensile stress corrosion testing apparatus as described in claim 4, characterized in that, The lever support (B2) and the lower limit plate (A12) are respectively embedded in the corresponding prefabricated grooves on the side walls of the left side plate (A2) and the right side plate (A3).

6. A method for tensile stress corrosion testing, characterized in that, The method includes the following steps: S1. Check the level (A14) to see if the bubble is in the center of the level (A14). If it is not in the center, adjust the tensile stress corrosion test device to a horizontal state by adjusting the adjustable support (A4). S2, Rotate lever lifting screw (A13) to lift the rear end of lever (B1) so that the tension system (D) is not subjected to tension; S3. Rotate the anti-tilt cover (D8) and adjust the direction of its U-shaped groove to be perpendicular to the limiting pin (D9). At this time, the corrosion liquid cylinder (D4) and the pull rod (D7) can be rotated around the limiting pin (D9) to tilt the corrosion liquid cylinder (D4) at a certain angle and rotate the cylinder opening towards the operator so that one end of the sample with threads at both ends can be screwed into the threaded hole of the pull rod (D7). S4. Unscrew the upper pull rod (D3) from the upper adjusting nut (D2) and remove it. Then screw the threaded hole of the upper pull rod (D3) into the other end of the test piece. S5. Rotate the connected pull rod (D7), corrosion liquid cylinder (D4), sample piece, and pull rod (D3) together around the limiting pin (D9) to a vertical position, and screw the external thread of the pull rod (D3) into the internal thread of the upper adjusting nut (D2) and lock it. S6. Rotate the anti-tilt cover (D8) and adjust the direction of its U-shaped groove to be parallel to the limiting pin (D9) to ensure that after the sample is pulled apart, the combination of the corrosion liquid cylinder (D4) and the pull rod (D7) will not rotate around the limiting pin (D9) to prevent the corrosion liquid from spilling out and causing harm. S7. Pour the specified ratio of etching solution into the etching solution cylinder (D4), ensuring the etching solution covers the specified area of ​​the sample. S8. Place the weight (C3) of the required force value stably on the weight plate (C2); S9. Rotate the lever lifting screw (A13) in the opposite direction to lower the rear end of the lever (B1), so that the sample is subjected to the set force under the combined action of the weight system (C) and the lever system (B); at this time, observe the position of the pointer (B11) on the pointer panel (A9) to determine whether the lever (B1) is in a horizontal position. If the lever (B1) is not in a horizontal position, the level of the lever (B1) can be adjusted by adjusting the lower adjusting nut (D11); S10. After a specified period of observation, observe whether the test specimen is broken under the combined action of corrosion and tensile force. If the test specimen is not broken within the specified time, it is deemed to be qualified; otherwise, it is deemed to be unqualified.

7. The tensile stress corrosion test method as described in claim 6, characterized in that, During the S3-S5 steps, the lower adjusting nut (D11) is adjusted to raise and lower the lower adjusting screw (D10), which in turn raises and lowers the pull rod (D7), the corrosion liquid cylinder (D4), the test piece, and the upper pull rod (D3) as a whole, in order to facilitate the installation of the test piece.

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