A metal material rotation bending corrosion fatigue test device and its use method

Abstract

The present invention discloses a rotating bending corrosion fatigue test device for metal materials and a method for using the device. The device comprises a corrosion box and a cover plate. The corrosion box is a trough structure with corresponding overflow ports formed on opposite side end surfaces of the corrosion box. The cover plate comprises a top plate and an inserting portion. The inserting portion comprises an inserting base and baffles disposed on both sides of the inserting base. A semicircular arc II is formed at the lower edge of the baffle and is vertically arranged below the top plate. When the cover plate is snapped onto the corrosion box, the outer wall of the baffle is tightly against the inner wall of the corrosion box with the overflow port and inserts downward. The semicircular arc II and the semicircular arc I formed by the overflow port are connected to form a channel for the test sample to pass through. The outer wall of the inserting portion and the inner wall of the corrosion box are matched without clearance to achieve the fixing of the cover plate. The fatigue test device has the characteristics of being able to apply liquid corrosive media, not easy to leak, and suitable for long-term unattended testing. It is suitable for performing rotating bending fatigue tests on metal materials in a liquid corrosive medium environment.

Description

Technical Field

[0001] The invention belongs to the technical field of metal material performance detection, and particularly relates to a metal material rotation bending corrosion fatigue test device and a use method. Background Art

[0002] Rotating bending fatigue testing is one of the oldest fatigue testing methods, initially used for fatigue testing of axles. The currently commonly used test standard, "GB / T4337 Rotating Bending Method for Fatigue Testing of Metallic Materials," is primarily used for fatigue testing of metal materials used in rotating shafts. Tests are typically conducted in room temperature air, though elevated temperature testing can be achieved with the addition of certain heating devices. However, suitable methods are currently lacking for evaluating the performance of metal materials used in corrosive environments, such as ship propellers, subjected to rotating bending fatigue loads in corrosive seawater. Rotating bending fatigue testing often utilizes a simply supported beam configuration, with the specimen clamped horizontally at both ends. The challenges of implementing rotating bending corrosion fatigue testing are how to apply a liquid corrosive medium to the rotating specimen while ensuring no leakage and easy installation. Furthermore, simply supported beam rotating bending fatigue tests often last for several days, often requiring unattended testing. The specimen fractures, and the test cycle count is automatically stopped by the specimen's fall, triggering a stop switch. To prevent the risk of high-speed rotation of the fractured specimen, the newly added corrosion device should not interfere with the automatic shutdown of the testing machine.

[0003] Existing corrosion testing systems immerse horizontal specimens in a liquid corrosive medium. This corrosive medium can be easily ejected by the high-speed rotating specimen, causing leakage and damage to the equipment. Furthermore, because the specimen must pass through a solution box and be immersed in the solution, the openings and sealing measures in the solution box can affect the specimen's drop when it breaks, resulting in a failure to automatically shut down the machine. Summary of the Invention

[0004] The purpose of the present invention is to provide a rotary bending corrosion fatigue test device and a method of use to solve the problems in the prior art. The rotary bending corrosion fatigue test device has the characteristics of being able to apply liquid corrosive media, not easy to leak and suitable for long-term unattended testing. It is suitable for performing rotary bending fatigue tests on metal materials in a liquid corrosive medium environment.

[0005] One of the purposes of the present invention is to provide a rotational bending corrosion fatigue test device for metal materials, comprising a corrosion box and a cover plate. The corrosion box is a trough structure, and corresponding overflow ports are formed on the opposite side end faces of the corrosion box. The cover plate comprises a top plate and an insertion portion. The insertion portion comprises an insertion base and baffles arranged on both sides of the insertion base. A semicircular arc II is formed at the lower edge of the baffle, and is vertically arranged below the top plate. When the cover plate is buckled on the corrosion box, the outer wall of the baffle is tightly attached to the inner wall of the corrosion box with the overflow port and inserted downward. The semicircular arc II and the semicircular arc I formed by the overflow port are docked to form a channel for the test sample to pass through. The outer wall of the insertion portion is matched with the inner wall of the corrosion box without gap to achieve fixation of the cover plate.

[0006] As a preferred solution, an inlet hole is opened in the center of the top plate, and an inlet connecting pipe is installed in the inlet hole. The inlet connecting pipe includes an inlet pipe and a spray pipe. The middle section of the spray pipe is connected to the outlet end of the inlet pipe, and the spray pipe has several water outlet holes evenly distributed along its length.

[0007] As a preferred solution, an overflow box is further included, which is arranged below the corrosion box and is used to contain the corrosion liquid flowing out of the overflow port of the corrosion box. An overflow hole is formed on one side of the overflow box, and an overflow pipe is connected to the overflow hole.

[0008] As a preferred solution, it also includes a driving mechanism for driving the test sample to rotate, the driving mechanism includes a first rotating shaft box and a second rotating shaft box, the first and second rotating shaft boxes are respectively connected to the two ends of the test sample to drive the test sample to rotate.

[0009] As a preferred embodiment, a reflux hole II is formed on one side wall of the corrosion box, and a reflux hole I is formed on the side wall of the overflow box. The reflux hole I corresponds to the reflux hole II in position and has the same diameter. The reflux hole II is connected to a reflux pipe, and the outer end of the reflux pipe passes outward from the reflux hole I.

[0010] As a preferred solution, the overflow box is provided with card slots on the two side walls below the overflow port, the slot opening is an opening structure with a larger top and a smaller bottom, and the size of the card slot matches the outer diameter of the first shaft box and the second shaft box.

[0011] As a preferred solution, the lower end surface of the overflow box is bonded to the test machine table, and a placement groove for placing the overflow box is formed above the test machine table.

[0012] As a preferred embodiment, it also includes a corrosive medium supply system, which includes a solution box, a pump, an overflow pipe, a return pipe and an inlet pipe. The pump is placed in the solution box, one end of the inlet pipe is connected to the pump outlet, and the other end is connected to the inlet of the inlet pipe, one end of the return pipe is connected to the return pipe, and the other end is connected to the solution box, and one end of the overflow pipe is connected to the overflow pipe, and the other end is connected to the solution box.

[0013] As a preferred solution, it also includes two stop rings, which are provided and installed on the sample to be tested and located correspondingly on the inner side of the overflow port to block the overflow port and prevent the corrosive medium from splashing out of the overflow port.

[0014] The second purpose of the present invention is to provide a method for using a metal material rotation bending corrosion fatigue test device.

[0015] Step 1: Place the overflow box in the center on the test machine table, fix the bottom with double-sided tape, and pass the overflow pipe through the overflow hole to connect it to the overflow pipe;

[0016] Step 2: Install the stop ring on the test sample, and install both ends of the test sample on the first rotating shaft box and the second rotating shaft box;

[0017] Step 3: Place the test sample through the corrosion box along the opening of the overflow port, and center the corrosion box inside the overflow box. Pass the reflux pipe through the reflux hole I and reflux hole II and connect it to the reflux pipe.

[0018] Step 4: Pass the inlet pipe from bottom to top through the inlet hole on the top plate, insert the cover plate to the bottom along the inner wall of the corrosion box, adjust the inlet pipe to the center position and connect it to the inlet pipe;

[0019] Step 5: Connect the inlet pipe to the pump, and place the outlet ends of the return pipe and overflow pipe in the solution box;

[0020] Step 6: Turn on the pump, and the corrosive medium is applied to the sample to be tested through the pump and the inlet pipe, and then returns to the solution box through the corrosion box and the return pipe to form a cycle;

[0021] Step 7: Adjust the pump's liquid flow rate so that the corrosive solution level is lower than the semicircular arc I of the overflow port of the corrosion box. After the corrosive medium circulation is stable, turn on the rotary bending fatigue testing machine and start the test.

[0022] Step 8. When the test sample breaks after a long-term test, it falls along the overflow port to the vicinity of its semicircular arc I. The first rotating shaft box and the second rotating shaft box automatically fall onto the slot and trigger the stop switch of the fatigue testing machine. The test sample stops rotating and the cycle count stops automatically to obtain the fatigue life of the test sample. Beneficial effects

[0023] First, the present invention, through structural improvements, includes an overflow box, a corrosion box, a stop ring, a cover plate, and a corrosive medium supply system. The corrosive medium supply system and the inlet pipe allow the corrosive medium to flow over the sample to be tested, forming a corrosive environment. The stop ring, cover plate, and baffle are designed to effectively prevent splashing and leakage of liquid corrosive medium. The overflow port, overflow box, and overflow pipe design form a double insurance to prevent overflow and leakage when the flow rate is too large or the return pipe is blocked. The slot and overflow port are designed to ensure that the test machine stop switch can be triggered after the sample breaks, ensuring test safety and accurate counting of fatigue cycle cycles, making it suitable for long-term unattended fatigue testing. The corrosion box with an open design allows for easy placement of the sample after it is installed on the testing machine. The return pipe is used to pass through the corrosion box and the overflow box at the same time, making it convenient to fix the position of the corrosion box. The invented rotary bending corrosion fatigue test device has the characteristics of being able to apply liquid corrosive medium, not easy to leak, and suitable for long-term unattended testing. It is suitable for rotary bending fatigue testing of metal materials in a liquid corrosive medium environment.

[0024] Secondly, the present invention optimizes the experimental method of the rotary bending corrosion fatigue test device, and optimizes the fatigue life test method through organic combination with the above-mentioned structure. Through the specially designed anti-splash and anti-overflow leakage experimental system geometry of the corrosive medium, it adopts the uninterrupted application of the corrosive medium on the sample, and the unattended automatic trigger stop mechanism, while adjusting the circulation flow of the corrosive medium, which not only ensures the safety and stability during long-term unattended fatigue experiments, but also can realize automatic stop when the fatigue experiment is completed, ensuring the accurate counting of fatigue cycle weeks. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 It is a structural schematic diagram of the corrosion device assembly of the present invention;

[0027] Figure 2 This is a schematic diagram of fatigue fracture of the sample of the present invention;

[0028] Figure 3 It is a structural schematic diagram of the present invention;

[0029] Figure 4 This is a schematic diagram of the present invention in use;

[0030] Markings in the figure: 1. Testing machine table, 2. Overflow box, 201. Overflow pipe, 202. Return hole I, 203. Card slot, 204. Overflow hole, 3. Corrosion box, 301. Overflow port, 302. Semicircular arc I, 303. Return hole II, 304. Return pipe, 4. Stop ring, 5. Sample to be tested, 6. First rotating shaft box, 7. Cover plate, 701. Top plate, 702. Inlet pipe, 703. Inlet hole, 704. Baffle, 705. Semicircular arc II, 8. Second rotating shaft box, 9. Corrosive medium supply system, 901. Overflow pipe, 902. Return pipe, 903. Inlet pipe, 904. Pump, 905, Solution box, 10. Stop switch, 11. Loading lever, 12. Weight hanging plate, 13. Upper fixed seat. DETAILED DESCRIPTION

[0031] The present invention is described in detail below by way of exemplary embodiments. However, it should be understood that elements, structures, and features in one embodiment may also be beneficially combined in other embodiments without further description.

[0032] It should be noted that: unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by persons having ordinary skills in the field to which the invention belongs. The words "one", "an" or "the" and the like used in the patent application specification and claims of the present invention do not express a quantitative limitation, but rather indicate the presence of at least one. Words such as "include" or "comprise" indicate that the elements or objects appearing before "include" or "comprises" include the elements or objects listed after "include" or "comprises" and their equivalents, but do not exclude other elements or objects with the same function.

[0033] This embodiment provides a rotary bending corrosion fatigue test device, comprising a test machine table 1, an overflow box 2, a corrosion box 3, a stop ring 4, a first rotating shaft box 6, a cover plate 7, a second rotating shaft box 8, and a corrosive medium supply system 9. The corrosion fatigue test device, in conjunction with a rotary bending fatigue tester, can perform a rotary bending corrosion fatigue performance test on a test sample 5. There are two stop rings 4, which are tightly fitted on the test sample 5. Preferably, the stop ring 4 is made of elastic material and is arranged at the intersection of the working section and the transition arc of the test sample 5. The test sample 5 is in the shape of a round rod, with its two ends respectively connected to the first rotating shaft box 6 and the second rotating shaft box 8 of the rotary bending fatigue tester. The overflow box 2, the corrosion box 3, and the cover plate 7 are arranged in sequence from bottom to top and placed on the test machine table 1. The test sample 5 passes through the overflow port 301 of the corrosion box 3. The overflow port 301 of the present invention is an open design. After the test sample 5 is installed on the rotary bending fatigue tester, the corrosion box 3 can be conveniently placed.

[0034] In this embodiment, the corrosive medium supply system 9 consists of an overflow pipe 901, a return pipe 902, an inlet pipe 903, a pump 904, and a solution box 905. The overflow pipe 901, return pipe 902, and inlet pipe 903 are silicone tubes with a diameter of 1 cm. The pump 904 has a head of 1.2 meters and a flow rate of 600 liters per hour. The solution box 905 is rectangular and has a capacity of 8 liters. The pump 904 is placed in the solution box 905. The inlet pipe 903 is connected to the inlet pipe 702 at one end and to the pump 904 at the other end. The return pipe 902 is connected to the corrosive box 3 at one end and placed on the solution box 905 at the other end. The overflow pipe 901 is connected to the overflow box 2 at one end and placed on the solution box 905 at the other end. The corrosive medium supply system 9 is connected to the cover plate 7 via the inlet pipe 903 , and the corrosion box 3 is connected to the corrosive medium supply system 9 via the return pipe 902 , thereby achieving continuous flow of the corrosive medium on the test sample 5 to form a corrosive environment.

[0035] In this embodiment, overflow ports 301 are provided on both sides of the corrosion box 3 adjacent to the first and second rotating shaft boxes 6 and 8. Overflow ports 301 are open at the top and semicircular at the bottom. After the rotary bending corrosion fatigue test apparatus is installed, the semicircular arc maintains a certain distance from the test specimen 5. This ensures that the test specimen 5 falls to a certain height after breaking, triggering the rotary bending fatigue tester stop switch 10 and ensuring accurate cycle counting during long-cycle fatigue testing. A reflow hole II 303 is provided on the other sidewall of the corrosion box 3. The reflow hole II 303 is located 2 cm below the lowest point of the overflow port 301. A reflow connection 304 is provided on the reflow hole II 303, connecting to the reflow pipe 902. The reflux pipe 304 passes through the corrosion box 3 and the overflow box 2 at the same time. The reflux hole I202 and the reflux hole II303 are on the same axis. The diameter of the reflux hole II303 and the reflux hole I202 on the overflow box 2 are the same. The reflux pipe 304 passes through the reflux hole I202 and the reflux hole II303 at the same time, which is convenient for fixing the position of the corrosion box 3.

[0036] In this solution, the overflow box 2 is arranged below the corrosion box 3 and is used to contain the corrosion liquid flowing out of the overflow port 301 of the corrosion box 3. The lower end surface is bonded to the test machine table 1, and a placement groove for the overflow box 2 is formed above the test machine table 1. The overflow box 2 is provided with a card slot 203 on both sides adjacent to the first rotating shaft box 6 and the second rotating shaft box 8. The first rotating shaft box 6 and the second rotating shaft box 8 fall into the card slot 203 when the test sample 5 breaks. The slot 203 has an opening structure with a larger top and a smaller bottom. The size of the card slot 203 matches the diameter and height of the first and second rotating shaft boxes 6 and 8, ensuring that the first rotating shaft box 6 and the second rotating shaft box 8 can trigger the stop switch 10 of the rotary bending fatigue testing machine after falling into it, ensuring accurate counting during long-cycle fatigue testing. A return hole I202 and an overflow hole 204 are provided on the other side of the overflow box 2. The overflow hole 204 is opened 1 cm lower than the lowest point of the card slot 203. An overflow connecting pipe 201 is provided on the overflow hole 204 to connect with the overflow pipe 901.

[0037] In this embodiment, the cover plate 7 is provided with a top plate 701 and an insertion portion on the top portion. The insertion portion includes an insertion base and baffles 704 arranged on both sides of the insertion base. The baffles 704 are arranged on both sides adjacent to the first rotating shaft box 6 and the second rotating shaft box 8. The baffles 704 are seamlessly matched with the inner wall of the corrosion box 3. The lower portion of the baffle 704 is a semicircular arc II 705. The baffle 704 is vertically arranged below the top plate 701. After the rotary bending corrosion fatigue test device is installed, the semicircular arc II 705 is close to the test sample 5. When the cover plate 7 is buckled onto the corrosion box 3, the outer wall of the baffle 704 is tightly attached to the inner side wall of the corrosion box 3 with the overflow port 301 and inserted downward. The semicircular arc II 705 and the semicircular arc I 302 formed by the overflow port 301 are connected to form a channel for the test sample 5 to pass through. The outer wall of the insertion portion is seamlessly matched with the inner wall of the corrosion box 3 to achieve the fixation of the cover plate 7. An inlet hole 703 is located at the center of the top plate 701. An inlet pipe 702 is installed above this hole, connecting it to the inlet pipe 903. This pipe 702 comprises an inlet pipe and a spray pipe. The middle section of the spray pipe is connected to the outlet of the inlet pipe. The spray pipe has several outlet holes evenly distributed along its length. The corrosive medium flowing through the outlet holes flows over the test sample 5, creating a corrosive environment. After the rotary bending corrosion fatigue test apparatus is installed, the inlet pipe is positioned at the center of the test sample.

[0038] In order to further improve its use effect and realize long-term unattended operation, when the test sample breaks during the unattended period, it is necessary to stop the drive of the above-mentioned test machine system. At the same time, the fatigue cycle count is accurate, and a switch trigger mechanism can also be provided. The switch trigger mechanism is used to trigger the stop switch 10 when the test sample breaks, so that the cycle count is automatically stopped to obtain the fatigue life of the test sample. The switch trigger mechanism includes an upper fixed seat 13, a lower fixed seat, a loading lever 11, a weight hanging plate 12 and a hook. The loading lever 11 includes a pressure rod, a support rod and a connecting cross bar. One end of the pressure rod is rotatably mounted on the lower fixed seat, and the other end is equipped with a weight hanging plate. The stop switch 10 is arranged below the middle section of the pressure rod, and the connecting cross bar is arranged above the pressure rod. The lower end of the support rod is vertically fixedly connected to the pressure rod, and the upper end of the support rod is rotatably connected to the middle section of the connecting cross bar. The hook includes a hook section and a connecting rod section that are integrally connected. The hooks on both sides of the upper end of the hook section are hung with the middle hanging shafts of the first and second rotating shaft boxes 6 and 8, and the lower end of the connecting rod section is rotatably connected to the two end sections of the connecting cross bar. The tail rotating shaft of the first rotating shaft box 6 is rotatably connected to the upper fixed seat 13. The upper fixed seat is fixedly set on the testing machine and two are relatively arranged. When the sample to be tested breaks, it will fall along the overflow port 301 to near the bottom semicircular arc I302, and the first rotating shaft box 6 and the second rotating shaft box 8 fall onto the slot 203. Due to the counterweight effect of the weight hanging plate 12, one end of the pressure rod is driven to rotate around a hinge at the fixed support, and the pressure rod triggers the stop switch 10 located in the middle section below it.

[0039] This embodiment also provides a method for using the above-mentioned rotating bending corrosion fatigue test device. Figures 1-4 :

[0040] a. Place the overflow box 2 centered on the rotary bending fatigue testing machine table 1 , fix the bottom with double-sided tape, and connect the overflow pipe 201 through the overflow hole 204 to the overflow pipe 901 .

[0041] b. Install the stop ring 4 on the test sample 5, and then install the test sample 5 on the first and second shaft boxes 6 and 8 of the rotary bending fatigue testing machine.

[0042] c. Pass the corrosion box 3 through the test sample 5 along the opening of the overflow port 301 and place it centrally in the overflow box 2. Pass the reflux pipe 304 through the reflux hole I202 and the reflux hole II303 and connect it to the reflux pipe 902.

[0043] d. Pass the inlet pipe 702 from bottom to top through the inlet hole 703 on the top plate 701, insert the cover plate 7 to the bottom along the baffle 704 and the inner wall of the corrosion box 3, adjust the inlet pipe 702 to the center position and connect it to the inlet pipe 903.

[0044] e. Connect the inlet pipe 903 to the pump 904 , and place the outlet ends of the return pipe 902 and the overflow pipe 901 in the solution box 905 .

[0045] f. Turn on the pump 904, and the corrosive medium is applied to the test sample 5 through the pump 904 and the inlet pipe 903, and returns to the solution box 905 through the corrosion box 3 and the return pipe 902 to form a cycle.

[0046] g. Adjust the water flow rate of pump 904 so that the corrosion solution level is lower than the semicircular arc I302 at the bottom of the corrosion box overflow port 301. After the corrosion medium circulation is stable, turn on the rotary bending fatigue testing machine to start the test.

[0047] h. When the test sample 5 breaks after a long-term test, it falls along the overflow port 301 to near the bottom semicircular arc I302, and the first and second rotating shaft boxes 6 and 8 fall onto the slot 203, triggering the fatigue testing machine stop switch 10, the sample stops rotating, and the cycle count stops automatically, thereby obtaining the fatigue life of the test sample 5.

[0048] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A rotating bending corrosion fatigue test device for metal materials, characterized by: The device comprises a corrosion box, a cover plate, an overflow box and a switch trigger mechanism. The corrosion box is a trough structure, and corresponding overflow ports are formed on opposite side end surfaces of the corrosion box. The cover plate comprises a top plate and an insertion portion. The insertion portion comprises an insertion base and baffles arranged on both sides of the insertion base. A semicircular arc II is formed on the lower edge of the baffle and is vertically arranged below the top plate. When the cover plate is buckled onto the corrosion box, the outer wall of the baffle is tightly attached to the inner side wall of the corrosion box with the overflow port and inserted downward. The semicircular arc II and the semicircular arc I formed by the overflow port are connected to form a channel for the sample to be tested to pass through. The outer wall of the insertion portion is matched with the inner wall of the corrosion box without clearance to achieve the fixation of the cover plate. The overflow box is provided with slots on the two side walls below the overflow port. The upper portion of the overflow port is open and the bottom is a semicircular arc I. After the rotary bending corrosion fatigue test apparatus is installed, the semicircular arc I maintains a certain distance from the sample to be tested. The control lever is connected with the control lever at the bottom end to the control lever, and the control lever is connected with the control lever at the control lever and the control lever respectively.

2. The rotating bending corrosion fatigue test device for metal materials according to claim 1, characterized in that: An inlet hole is opened at the center of the top plate, and an inlet pipe is installed in the inlet hole. The inlet pipe includes an inlet pipe and a spray pipe. The middle section of the spray pipe is connected to the outlet end of the inlet pipe, and the spray pipe has a plurality of water outlet holes evenly distributed along its length.

3. The rotating bending corrosion fatigue testing device for metal materials according to claim 2, characterized in that: The overflow box is arranged below the corrosion box and is used to contain the corrosion liquid flowing out of the overflow port of the corrosion box. An overflow hole is formed on one side of the overflow box, and an overflow pipe is connected to the overflow hole.

4. The rotating bending corrosion fatigue testing device for metal materials according to claim 3, characterized in that: The device also includes a driving mechanism for driving the sample to be tested to rotate. The driving mechanism includes a first rotating shaft box and a second rotating shaft box. The first and second rotating shaft boxes are respectively connected to the two ends of the sample to be tested and drive the sample to be tested to rotate.

5. The metal material rotation bending corrosion fatigue test device according to claim 2, characterized in that: A reflux hole II is formed on one side wall of the corrosion box, and a reflux hole I is formed on the side wall of the overflow box. The reflux hole I corresponds to the reflux hole II in position and has the same diameter. The reflux hole II is connected to a reflux pipe, and the outer end of the reflux pipe passes outward from the reflux hole I.

6. The rotating bending corrosion fatigue testing device for metal materials according to claim 3, characterized in that: The slot opening is an opening structure that is larger at the top and smaller at the bottom, and the size of the slot matches the outer diameters of the first rotating shaft box and the second rotating shaft box.

7. The rotating bending corrosion fatigue testing device for metal materials according to claim 3, characterized in that: The lower end surface of the overflow box is bonded to the test machine table, and a placement groove for placing the overflow box is formed above the test machine table.

8. The metal material rotation bending corrosion fatigue test device according to claim 7, characterized in that: It also includes a corrosive medium supply system, which includes a solution box, a pump, an overflow pipe, a return pipe and an inlet pipe. The pump is placed in the solution box, one end of the inlet pipe is connected to the pump outlet, and the other end is connected to the inlet of the inlet pipe, one end of the return pipe is connected to the return pipe, and the other end is connected to the solution box, and one end of the overflow pipe is connected to the overflow pipe, and the other end is connected to the solution box.

9. The rotating bending corrosion fatigue testing device for metal materials according to claim 3, characterized in that: It also includes two stop rings, which are installed on the sample to be tested and located correspondingly on the inner side of the overflow port to block the overflow port and prevent the corrosive medium from splashing out of the overflow port.

10. A method for using the metal material rotating bending corrosion fatigue testing device according to any one of claims 1 to 9, characterized in that: Step 1: Place the overflow box in the center on the test machine table, fix the bottom with double-sided tape, and pass the overflow pipe through the overflow hole to connect it to the overflow pipe; Step 2: Install the stop ring on the test sample, and install both ends of the test sample on the first rotating shaft box and the second rotating shaft box; Step 3: Place the test sample through the corrosion box along the opening of the overflow port, and center the corrosion box inside the overflow box. Pass the reflux pipe through the reflux hole I and reflux hole II and connect it to the reflux pipe. Step 4: Pass the inlet pipe from bottom to top through the inlet hole on the top plate, insert the cover plate to the bottom along the inner wall of the corrosion box, adjust the inlet pipe to the center position and connect it to the inlet pipe; Step 5: Connect the inlet pipe to the pump, and place the outlet ends of the return pipe and overflow pipe in the solution box; Step 6: Turn on the pump, and the corrosive medium is applied to the sample to be tested through the pump and the inlet pipe, and then returns to the solution box through the corrosion box and the return pipe to form a cycle; Step 7: Adjust the pump's liquid flow rate so that the corrosive solution level is lower than the semicircular arc I of the overflow port of the corrosion box. After the corrosive medium circulation is stable, turn on the rotary bending fatigue testing machine and start the test. Step 8. When the test sample breaks after a long-term test, it falls along the overflow port to the vicinity of its semicircular arc I. The first rotating shaft box and the second rotating shaft box automatically fall onto the slot and trigger the stop switch of the fatigue testing machine. The test sample stops rotating and the cycle count stops automatically to obtain the fatigue life of the test sample.

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