A stress corrosion device and its usage method under fluid scouring conditions

Abstract

A stress corrosion device under fluid scouring conditions belongs to the technical field of erosion corrosion tests. It includes a frame. A power input device is installed on the bottom plate of the frame. A liquid storage tank and a hydraulic tensile machine are installed on the frame. A cover plate is installed on the top of the liquid storage tank. A fixture is installed in the liquid storage tank, and the scouring attack angle is changed by rotating the fixture. A usage method of the stress corrosion device under fluid scouring conditions includes the following steps: Connect the working electrode wire to the top end of the specimen; Install the processed specimen on the fixture; Tension the specimen; Install the tensioned specimen into the liquid storage tank; Fill the liquid storage tank with the experimental medium; Close the cover plate and fasten the mechanical lock; Start the motor and the heating rod, and start the electrochemical test after the flow rate and temperature of the experimental medium are stable. By rotating the fixture, the fixing column is inserted into the fixing groove to change the scouring attack angle, which solves the problem that the previous erosion corrosion test device cannot apply tensile stress and change the attack angle.

Description

Technical Field

[0001] The present invention belongs to the technical field of erosion-corrosion tests, and particularly relates to a stress corrosion device and a usage method under fluid erosion conditions. Background Art

[0002] Erosion-corrosion is a material damage phenomenon caused by the high-speed relative movement between the material surface and the medium. Stress corrosion generally refers to the material failure caused by the synergistic action of the corrosion medium and the tensile stress. Currently, the existing erosion-corrosion experimental equipment generally lacks the function of applying stress to the specimen, and there are problems such as low relative velocity between the specimen and the experimental medium, inability to change the erosion attack angle, and unstable electrochemical measurement at high flow rates in the rotary erosion-corrosion experimental device. Based on the above deficiencies, the present invention aims to solve the problems existing in the traditional rotary erosion-corrosion experimental device. The key point is to add the function of applying stress to the specimen on the basis of the traditional rotary erosion experiment device, realizing the cross-integration of erosion-corrosion and stress corrosion test technologies. Summary of the Invention

[0003] The purpose of the present invention is to provide a stress corrosion device and a usage method under fluid erosion conditions. The specimen is fixed on the base of the water storage tank through a special fixture. Since the specimen is in a fixed state, the flow velocity of the medium is the actual erosion velocity, and there is no problem of relative velocity reduction. The fixture can stretch the specimen through a hydraulic tensile machine. There is a fixed groove on the fixture base, and the erosion attack angle can be changed by rotating the fixture and inserting the fixed column into the fixed groove. This solves the problems that the traditional rotary erosion-corrosion experimental device cannot apply tensile stress and change the attack angle.

[0004] A stress corrosion device under fluid erosion conditions includes a frame. A power input device is installed on the bottom plate of the frame, and a liquid storage tank for storing the experimental medium and a hydraulic tensile machine for stretching the specimen are installed on the top plate of the frame. The output end of the power input device is rotatably installed at the bottom of the liquid storage tank through a lock. A cover plate for preventing the leakage of the experimental medium is installed on the top of the liquid storage tank. A fixture for fixing the specimen is installed in the liquid storage tank through a fixed column, and the erosion attack angle is changed by rotating the fixture.

[0005] The fixtures are circumferentially and arrayed around the liquid storage tank. The fixture includes a base, and force-applying screws are equidistantly installed along the circumference of the base. A partition is fixedly installed on the force-applying screw through a force-applying nut. An installation hole is opened at the center of the partition, and a specimen is installed in the installation hole. Fixing pins for fixing the specimen on the partition are installed at the top and bottom of the specimen respectively.

[0006] An empty groove extending towards the center of the base is opened on the outer surface of the base. Rotate the fixture, and the erosion attack angle is changed by inserting the fixed column through the through hole of the base of the liquid storage tank and into the empty groove of the fixture base.

[0007] The liquid storage tank is in the shape of a hopper. The base of the liquid storage tank is located inside the cavity of the liquid storage tank, and part of it is processed with a fixture installation groove. Radial holes for installing fixed columns are processed on the groove wall of the installation groove. The fixed columns pass through the radial holes on the liquid storage tank and are inserted into different slots on the fixture base, thereby changing the erosion attack angle. A pipeline for discharging the experimental medium is connected to the side wall of the funnel-shaped part at the bottom of the liquid storage tank, and the outlet end of the pipeline penetrates through the frame. A vacuum layer is provided in the part of the liquid storage tank above the frame to prevent heat dissipation through the setting of the vacuum layer.

[0008] A reference electrode, a counter electrode, a thermometer and a flowmeter are installed on the cover plate. Heating rods are symmetrically installed on the inner wall of the liquid storage tank.

[0009] The hydraulic tensile machine includes an outer shell installed on the bottom plate of the frame. A hydraulic cylinder is installed inside the outer shell. The top of the piston rod of the hydraulic cylinder is installed with a moving platform. Long sliding grooves are symmetrically opened on the shell wall of the outer shell. A counterweight block connected to the moving platform is installed at one of the long sliding grooves, and a cantilever connected to the moving platform is slidably installed at the other long sliding groove. An upper clamping device is installed at the front end of the cantilever, and a lower clamping device located on the bottom plate is installed directly opposite below the upper clamping device.

[0010] The lower clamping device includes a disc-shaped clamping base. The inner wall of the clamping part of the clamping base is arc-shaped and processed with anti-slip tooth patterns. A sliding groove is opened at the bottom of the clamping base. An arc-shaped tightening block is slidably installed on the sliding groove. The inner wall surface of the arc-shaped tightening block is processed with anti-slip tooth patterns. A lower push rod is rotatably installed on the base through a thread, and the end of the lower push rod is connected to the outer wall surface of the arc-shaped tightening block. The arc-shaped tightening block is moved towards the clamping part by rotating the lower push rod to clamp the fixture tightly.

[0011] The upper clamping device includes a rectangular clamping upper seat. A groove with an opening facing downwards is opened on the clamping upper seat. A sliding groove is opened at the bottom of the groove. A tightening block is slidably installed on the sliding groove. Anti-slip tooth patterns are processed on the side wall of the tightening block and the clamping groove wall of the groove, and the two are arranged opposite to each other. An upper push rod is rotatably installed on the clamping upper seat through a thread, and the end of the upper push rod is connected to the outer side wall of the tightening block. The tightening block is pushed towards one side of the clamping groove wall by rotating the upper push rod to clamp the top of the specimen tightly.

[0012] The power input device includes a motor and a fixing bracket. The fixing bracket and the motor are respectively installed on the inner cavity bottom plate of the frame. The output shaft of the motor passes through the fixing bracket, and a large pulley is connected to the part passing through the fixing bracket by a key. A high-speed shaft and a transmission shaft are successively rotatably installed on the fixing bracket from one end of the output shaft to one end of the liquid storage tank. A tension pulley and a small pulley are respectively connected to the high-speed shaft and the transmission shaft by keys. A belt is installed on the large pulley, the tension pulley and the small pulley. The part of the transmission shaft above the small pulley is installed on the liquid storage tank through a buckle, and a blade is installed on the part extending into the liquid storage tank. The flow rate of the experimental medium is changed by adjusting the rotation speed of the motor.

[0013] A method for using a stress corrosion device under fluid scouring conditions includes the following steps:

[0014] Step 1, the top end of the specimen is encapsulated with epoxy resin to connect the working electrode wire;

[0015] Step 2, insert the processed specimen into the fixture partition through the installation hole, and insert the fixing pins into both ends of the specimen to fix the specimen on the fixture;

[0016] Step 3, fix the fixture with the specimen installed in the lower clamping device of the hydraulic tensile machine, and at the same time clamp the upper end of the specimen through the upper clamping device; start the hydraulic cylinder, apply a tensile stress to the specimen through the elongation of the piston rod to the required experimental value, and tighten the force-applying nuts on both sides of the upper and lower partitions of the fixture to ensure that the applied tensile stress value on the specimen remains unchanged;

[0017] Step 4, take out the fixture from the hydraulic tensile machine, place the fixture in the installation groove, rotate the fixture to make the corresponding empty groove of the fixture base in line with the radial hole of the installation groove, and make the fixing column pass through the radial hole of the installation groove and the empty groove of the fixture base to fix the scouring attack angle;

[0018] Step 5, lead out the working electrode wire connecting the specimen through the wire conduit;

[0019] Step 6, load the experimental medium into the liquid storage tank;

[0020] Step 7, close the cover plate and fasten the mechanical buckle, and insert and fix the reference electrode and the counter electrode through the buckle on the cover plate;

[0021] Step 8, connect the reference electrode, the counter electrode and the working electrode to the electrochemical workstation respectively; start the motor and the heating rod, and start the electrochemical test after the flow rate and temperature of the experimental medium are stable.

[0022] The technical effects of the present invention are as follows:

[0023] 1. The specimen is placed in the fixture through the fixing pins, and a constant tensile stress is applied to the specimen through the hydraulic tensile machine and the force-applying nuts on the fixture.

[0024] 2. The fixture base is grooved in the 30°, 60° and 90° directions, the fixture can be rotated, and the fixed column is inserted into the empty slot of the fixture base through the through hole of the liquid storage tank base to change the attack angle.

[0025] 3. The specimen is in a fixed state during scouring, enabling electrochemical testing to be carried out even at high flow rates.

[0026] 4. The specimen is in a fixed state during scouring, the flow rate of the experimental medium is the scouring speed, and there is no problem of small relative speed.

[0027] 5. Through the settings of the heating rod and the motor, the present invention can adjust the temperature and flow rate of the experimental medium. Description of the Drawings

[0028] Figure 1 3D view of the stress corrosion device under fluid scouring conditions of the present invention;

[0029] Figure 2 Cross-sectional view of the stress corrosion device under fluid scouring conditions of the present invention;

[0030] Figure 3 Cross-sectional view of the hydraulic tensile machine of the stress corrosion device under fluid scouring conditions of the present invention;

[0031] Figure 4 Cross-sectional view of the fixture of the stress corrosion device under fluid scouring conditions of the present invention;

[0032] 1 - Liquid storage tank, 2 - Vacuum layer, 3 - Heating rod, 4 - Impeller, 5 - Force - adding screw, 6 - Force - adding nut, 7 - Specimen, 8 - Partition board, 9 - Fixed column, 10 - Reference electrode, 11 - Counter electrode, 12 - Thermometer, 13 - Flow meter, 14 - Frame, 15 - High - speed shaft, 17 - Large pulley, 18 - Fixed bracket, 19 - Motor, 20 - Small pulley, 21 - Water valve, 22 - Cover plate, 23 - Fixed pin, 24 - Lock, 25 - Tensioning pulley, 26 - Outer shell, 27 - Moving platform, 28 - Cantilever, 29 - Counterweight, 30 - Clamping base, 31 - Clamping part, 32 - Arc - shaped pressing block, 33 - Lower push rod, 34 - Clamping upper seat, 35 - Screw, 36 - Pressing block, 37 - Upper push rod, 38 - Hydraulic cylinder, 39 - Transmission shaft, 40 - Conduit threading tube. Detailed Description of the Invention

[0033] The following further elaborates on the present invention in conjunction with the drawings and embodiments.

[0034] As Figure 1 and Figure 2As shown in the figure, a stress corrosion device under fluid scouring conditions includes a frame 14. A power input device is installed on the bottom plate of the frame 14, and a liquid storage tank 1 for storing experimental medium and a hydraulic tensile machine for stretching a specimen 7 are installed on the top plate of the frame 14. The output end of the power input device is rotationally installed at the bottom of the liquid storage tank 1 through a mechanical latch. In the liquid storage tank 1, a fixture for fixing the specimen 7 is installed through a fixing column 9. The scouring attack angle is changed by rotating the fixture. In this embodiment, 12 fixtures are arranged in a circular array with the liquid storage tank 1 as the center. A cover plate 22 is installed on the top of the liquid storage tank 1 and is sealed with a sealing rubber. At the same time, a mechanical latch is installed, and the mechanical latches are arranged at equal intervals along the circumferential direction of the cover plate 22. When in use, the mechanical latches are fastened to ensure that the experimental medium in the liquid storage tank is full under high flow rate and prevent leakage; the cover plate 22 is made of a transparent material to facilitate observing the internal situation of the liquid storage tank.

[0035] A reference electrode 10, a counter electrode 11, a thermometer 12, and a flow meter 13 are installed on the cover plate 22 through a latch 24. The counter electrode 11 and the reference electrode 10 are placed on the cover plate 22 at 120° with the center of the liquid storage tank 1 and are sealed with a sealing rubber. The specimen 7 is encapsulated with epoxy resin as a working electrode, and a three-electrode system is formed to realize electrochemical measurement. Since the working electrode is fixed, high-flow-rate electrochemical measurement can be realized. The wire of the working motor passes through a conduit 40 and extends out of the cover plate 22 to be connected to an electrochemical workstation; Heating rods 3 are symmetrically installed on the inner wall of the liquid storage tank 1, and the heating rods 3 are arranged higher than the top of the impeller 4.

[0036] As Figure 4 shown in the figure, the fixture includes a circular base. Along the circumferential direction of the base, force-applying screws 5 are installed at equal intervals. In this embodiment, there are four force-applying screws 5. Partition plates 8 are fixedly installed on the force-applying screws 5 through force-applying bolts. In this embodiment, there are two partition plates 8, and force-applying nuts 6 are distributed on the upper and lower sides of the partition plates 8 to fix the partition plates 8 on the force-applying studs. By loosening and tightening the force-applying nuts 6, the distance between the two partition plates 8 on the fixture is increased to maintain the tensile force applied by the hydraulic tensile machine to the tensile specimen 7. An installation hole for installing the specimen 7 is opened at the center of the partition plate 8. The installation hole is a through hole, and the cross-sectional shape of the installation hole is rectangular. The specimen 7 is installed in the installation holes of the two partition plates 8, and fixing pins 23 for fixing the specimen 7 on the partition plates 8 are installed at the top and bottom of the specimen 7 respectively.

[0037] An empty groove extending towards the center of the base is opened on the outer surface of the base. In this embodiment, there are three empty grooves, which are located at the 30°, 60°, and 90° directions of the base respectively. The scouring attack angle is changed by inserting the fixing column 9 through the radial hole of the base of the liquid storage tank 1 into different empty grooves of the fixture base.

[0038] The liquid storage tank 1 is conical. A vacuum layer 2 is provided in the part of the liquid storage tank 1 above the frame 14. The vacuum layer 2 is provided to prevent heat dissipation. The base of the liquid storage tank 1 is machined with a fixture installation groove inside the cavity of the liquid storage tank 1, and radial holes for installing the fixing column 9 are machined on the groove wall of the installation groove. The fixing column 9 passes through the radial holes on the liquid storage tank 1 and is inserted into different slots on the fixture base, thereby changing the erosion angle of attack. A water outlet pipe for discharging the experimental medium is connected to the side wall of the funnel-shaped part at the bottom of the liquid storage tank 1, and a water valve 21 is provided on the water outlet pipe. The outlet end of the water outlet pipe penetrates through the frame 14. The water outlet pipe is provided to facilitate the replacement of the experimental medium.

[0039] As Figure 3 shown, the hydraulic tensile machine includes a housing 26 installed on the bottom plate of the frame 14. A hydraulic cylinder 38 is installed inside the housing 26. The top of the piston rod of the hydraulic cylinder 38 is installed with a moving platform 27. Long sliding grooves are symmetrically opened on the wall of the housing 26. A counterweight 29 connected to the moving platform 27 is installed at one of the long sliding grooves, and a cantilever 28 connected to the moving platform 27 is slidably installed at the other long sliding groove. An upper clamping device is installed at the front end of the cantilever 28, and a lower clamping device located on the bottom plate is installed directly opposite the lower side of the upper clamping device.

[0040] The lower clamping device includes a disc-shaped clamping base 30. The inner wall of the clamping part 31 of the clamping base 30 is arc-shaped and machined with anti-slip tooth patterns. A sliding groove is opened at the bottom of the groove of the clamping base 30. An arc-shaped tightening block 32 is slidably installed on the sliding groove. The inner wall surface of the arc-shaped tightening block 32 is machined with anti-slip tooth patterns. A lower push rod 33 is rotatably installed on the base through a thread. The end of the lower push rod 33 is connected to the outer wall surface of the arc-shaped tightening block 32. By rotating the lower push rod 33, the arc-shaped tightening block 32 moves towards the clamping part 31, and the fixture is tightened under the action of the anti-slip tooth patterns on the arc-shaped tightening block 32 and the clamping part 31.

[0041] The upper clamping device includes a rectangular clamping upper seat 34. The clamping upper seat 34 is threadedly connected to one end of a screw 35, and a nut is screwed on the screw 35 to fixedly install the screw 35 on the clamping upper seat 34. The other end of the screw 35 is screwed to the cantilever 28, and the other end of the screw 35 is also fixed to the cantilever 28 by a nut installed on the screw 35. An opening facing downwards is provided on the clamping upper seat 34. A sliding groove is opened at the bottom of the groove. A tightening block 36 is slidably installed on the sliding groove. Anti-slip tooth patterns are machined on the side wall of the tightening block 36 and the clamping groove wall of the groove, and the two are arranged opposite to each other. An upper push rod 37 is rotatably installed on the clamping upper seat 34 through a thread. The end of the upper push rod 37 is connected to the outer side wall of the tightening block 36. By rotating the upper push rod 37, the tightening block 36 is pushed to move towards one side of the clamping groove wall to clamp the top of the specimen 7. A tensiometer is installed on the upper clamping device.

[0042] The power input device includes a motor 19 and a fixing bracket 18. The fixing bracket 18 and the motor 19 are respectively installed on the inner cavity bottom plate of the frame 14. The output shaft of the motor 19 passes through a part of the fixing bracket 18 and is connected with a large pulley 17 by a key. A high-speed shaft 15 and a transmission shaft 39 are successively rotatably installed on the fixing bracket 18 from one end of the output shaft to one end of the liquid storage tank 1. A tension pulley 25 and a small pulley 20 are respectively connected with the high-speed shaft 15 and the transmission shaft 39 by keys. A belt is installed on the large pulley 17, the tension pulley 25 and the small pulley 20. The part of the transmission shaft 39 above the small pulley 20 is installed on the liquid storage tank 1 through a buckle 24, and a blade 4 is installed on the part extending into the liquid storage tank 1. The flow rate of the experimental medium is changed by adjusting the rotation speed of the motor 19.

[0043] A method for using a stress corrosion device under fluid scouring conditions includes the following steps:

[0044] Step 1, the top end of the specimen 7 is encapsulated and connected to the working electrode wire with epoxy resin;

[0045] Step 2, insert the processed specimen 7 into the fixture partition 8 through the mounting hole, and insert the fixing pins 23 into both ends of the specimen 7 to fix the specimen on the fixture;

[0046] Step 3, place the fixture with the specimen 7 in the lower clamping device of the hydraulic tensile machine and place it close to the clamping part 31. Then rotate the lower push rod 33 forward to push the arc-shaped pressing block 32 to move towards the clamping part 31 to press against the fixture base; start the hydraulic cylinder 38, drive the moving platform 27 through the piston rod to adjust the position of the upper clamping device, so that the clamping groove wall of the upper clamping device is close to the upper end of the specimen. The hydraulic cylinder 38 stops working. Then rotate the upper push rod 37 forward to push the pressing block 36 to move towards the clamping groove wall side to clamp the upper end of the specimen 7; start the hydraulic cylinder 38 again, the piston rod extends to apply a tensile stress to the specimen 7. When the tensile stress is stable at the required value, tighten the force applying nuts 6 on both sides of the upper and lower partitions 8 of the fixture to ensure that the applied tensile stress value to the specimen 7 remains unchanged;

[0047] Step 4, rotate the upper push rod 37 and the lower push rod 33 in the reverse direction respectively, so that the arc-shaped pressing block 32 and the pressing block 36 move away from the clamping part 31 and the clamping groove wall respectively to loosen the fixture and the specimen 7; then take out the fixture from the hydraulic tensile machine, place the fixture in the installation groove, rotate the fixture so that the corresponding empty groove of the fixture base is in a straight line with the radial hole of the installation groove, and make the fixing column 9 pass through the radial hole of the installation groove and the empty groove of the fixture base to fix the scouring attack angle;

[0048] Step 5, lead out the working electrode wire connecting the specimen 7 through the wire pipe 40;

[0049] Step 6, load the experimental medium into the liquid storage tank 1;

[0050] Step 7: Close the cover plate 22 and fasten the mechanical latch. Insert the reference electrode 10 and the counter electrode 11 through the latch 24 on the cover plate 22 and fix them to the cover plate 22.

[0051] Step 8: Connect the reference electrode 10, the counter electrode 11, and the working electrode to the electrochemical workstation respectively; start the motor 19 and the heating rod 3, and start the electrochemical test after the flow rate and temperature of the experimental medium are stable.

Claims

1. A stress corrosion device under fluid scouring conditions, characterized in that It includes a frame. A power input device is installed on the bottom plate of the frame. A liquid storage tank for storing experimental medium and a hydraulic tensile machine for stretching specimens are installed on the top plate of the frame. The output end of the power input device is rotatably installed at the bottom of the liquid storage tank through a buckle. A cover plate for preventing the leakage of experimental medium is installed on the top of the liquid storage tank. A fixture for fixing the specimen is installed in the liquid storage tank through a fixed column, and the erosion attack angle is changed by rotating the fixture; the fixtures are circumferentially arranged in an array centered on the liquid storage tank; the fixture includes a base, and force-applying screws are installed at equal intervals along the circumference of the base. A partition plate is fixedly installed on the force-applying screw through a force-applying nut. An installation hole is opened at the center of the partition plate, and a specimen is installed in the installation hole. Fixing pins for fixing the specimen on the partition plate are installed at the top and bottom ends of the specimen respectively; the liquid storage tank is of a hopper type, the base of the liquid storage tank is located in the cavity of the liquid storage tank, and part of it is processed with a fixture installation groove, and radial holes for installing the fixed column are processed on the groove wall of the installation groove. The fixed column passes through the radial hole on the liquid storage tank and is inserted into different slots on the fixture base, so as to change the erosion attack angle; the fixture with the specimen is fixedly installed in the lower clamping device of the hydraulic tensile machine, and at the same time, the upper end of the specimen is clamped by the upper clamping device; the hydraulic cylinder is started, and a tensile stress is applied to the specimen by the elongation of the piston rod to the required experimental value, and the force-applying nuts on both sides of the partition plate of the fixture are tightened to ensure that the value of the tensile stress applied to the specimen remains unchanged.

2. The stress corrosion device under fluid scouring conditions according to claim 1, characterized in that: An empty groove extending towards the center of the base is opened on the outer surface of the base. The fixture is rotated, and the erosion attack angle is changed by inserting the fixed column through the through hole of the base of the liquid storage tank and into the empty groove of the fixture base.

3. The stress corrosion device under fluid scouring conditions according to claim 1, characterized in that: A pipeline for discharging experimental medium is connected to the side wall of the hopper-shaped part at the bottom of the liquid storage tank, and the outlet end of the pipeline penetrates through the frame; a vacuum layer is arranged on the part of the liquid storage tank above the frame, and heat dissipation is prevented through the setting of the vacuum layer.

4. A stress corrosion device under fluid erosion conditions according to claim 1, characterized in that: A reference electrode, a counter electrode, a thermometer and a flow meter are installed on the cover plate; heating rods are symmetrically installed on the inner wall of the liquid storage tank.

5. A stress corrosion device under fluid erosion conditions according to claim 1, characterized in that: The hydraulic tensile machine includes an outer housing installed on the bottom plate of the frame. A hydraulic cylinder is installed in the outer housing. The top of the piston rod of the hydraulic cylinder is installed with a moving platform. Long sliding grooves are symmetrically opened on the wall of the outer housing. A counterweight block connected to the moving platform is installed at one of the long sliding grooves, and a cantilever connected to the moving platform is slidably installed at the other long sliding groove. An upper clamping device is installed at the front end of the cantilever, and a lower clamping device located on the bottom plate is installed directly opposite below the upper clamping device.

6. The stress corrosion device under fluid scouring conditions according to claim 5, characterized in that: The lower clamping device includes a disc-shaped clamping base. The inner wall of the clamping part of the clamping base is arc-shaped and processed with anti-slip tooth patterns. A sliding groove is opened at the bottom of the groove of the clamping base. An arc-shaped top block is slidably installed on the sliding groove. The inner wall surface of the arc-shaped top block is processed with anti-slip tooth patterns. A lower push rod is rotatably installed on the base through a thread, and the end of the lower push rod is connected to the outer wall surface of the arc-shaped top block. The arc-shaped top block is moved towards the clamping part by rotating the lower push rod to clamp the fixture tightly.

7. A stress corrosion device under fluid erosion conditions according to claim 5, characterized in that: The upper clamping device includes a rectangular clamping upper seat. A groove with a downward opening is formed on the clamping upper seat. A slideway is formed at the bottom of the groove. A pressing block is slidably mounted on the slideway. Anti-slip tooth patterns are machined on the side wall of the pressing block and the clamping groove wall of the groove, and the two are arranged opposite to each other. An upper push rod is rotationally mounted on the clamping upper seat through a thread. The end of the upper push rod is connected to the outer side wall of the pressing block. By rotating the upper push rod, the pressing block is pushed to move towards the clamping groove wall side to clamp the top of the specimen.

8. A stress corrosion device under fluid erosion conditions according to claim 1, characterized in that: The power input device includes a motor and a fixing frame. The fixing frame and the motor are respectively mounted on the inner cavity bottom plate of the frame. The output shaft of the motor passes through a part of the fixing frame and is key-connected with a large belt pulley. A high-speed shaft and a transmission shaft are sequentially rotationally mounted on the fixing frame from one end of the output shaft to one end of the liquid storage tank. A tension pulley and a small belt pulley are respectively key-connected to the high-speed shaft and the transmission shaft. A belt is mounted on the large belt pulley, the tension pulley and the small belt pulley. The part of the transmission shaft above the small belt pulley is mounted on the liquid storage tank through a buckle, and a paddle is mounted on the part extending into the liquid storage tank. The flow rate of the experimental medium is changed by adjusting the rotation speed of the motor.

9. The method of using a stress corrosion device under fluid scouring conditions according to claim 1, characterized in that It includes the following steps: Step 1, the top end of the specimen is encapsulated and connected to the working electrode wire with epoxy resin. Step 2, the processed specimen is inserted into the fixture partition through the mounting hole, and the fixing pins are inserted into both ends of the specimen to fix the specimen on the fixture. Step 3, the fixture with the specimen is fixedly installed in the lower clamping device of the hydraulic tensile machine, and at the same time, the upper end of the specimen is clamped by the upper clamping device; the hydraulic cylinder is started, and a tensile stress is applied to the specimen by the elongation of the piston rod to the required experimental value. The force-applying nuts on both sides of the upper partition of the fixture are tightened to ensure that the value of the tensile stress applied to the specimen remains unchanged. Step 4, take out the fixture from the hydraulic tensile machine, place the fixture in the mounting groove, rotate the fixture to make the corresponding empty groove of the fixture base in a straight line with the radial hole of the mounting groove, and make the fixing column penetrate the radial hole of the mounting groove and the empty groove of the fixture base to fix the erosion attack angle. Step 5, lead out the working electrode wire connecting the specimen through the wire conduit. Step 6, load the experimental medium into the liquid storage tank. Step 7, close the cover plate and fasten the mechanical buckle, and insert and fix the reference electrode and the counter electrode through the buckle on the cover plate. Step 8, connect the reference electrode, the counter electrode and the working electrode to the electrochemical workstation respectively; start the motor and the heating rod, and start the electrochemical test after the flow rate and temperature of the experimental medium are stable.

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