Experimental device and method for testing corrosion rate

Abstract

The invention discloses an experimental device for testing a corrosion rate in the field of material corrosion performance experiments, and the experimental device is used for carrying out a corrosion experiment on a spherical metal test piece, and the experimental device comprises a corrosion container which is cylindrical and is filled with a corrosion solution; the circulating pipeline is connected to the corrosion container, is drawn out from the upper part of the corrosion container and is fed from the bottom; the liquid spraying suspension assembly is arranged at the feeding end of the circulating pipeline; the liquid preparation assembly is arranged on the circulating pipeline; the controller is electrically connected with the liquid spraying suspension assembly and the liquid preparation assembly; the invention further discloses a corrosion rate experiment method. The device has the beneficial effects that the circulating pipeline and the liquid spraying suspension assembly are arranged, the spherical metal test piece is suspended in the corrosion solution through thrust of fluid, the problem of incomplete corrosion is avoided, and compared with an electromagnetic eddy current suspension mode, the device is simpler in structure and lower in cost. And the problem that the experimental result is influenced by the temperature change of the corrosion solution is avoided.

Description

Technical Field

[0001] The present invention relates to the field of experimental tests on the corrosion performance of materials, and particularly to an experimental device and method for testing the corrosion rate. Background Art

[0002] Corrosion refers to the physical-chemical interaction between a metal and its environment, as a result of which the properties of the metal change, and often the functions of the metal, the environment, or the technical system composed of them are damaged. In industrial production, there are often problems such as the failure of equipment and components due to the corrosion of metal materials, posing a serious threat to production safety. Metal corrosion is generally divided into uniform corrosion and local corrosion. Among them, uniform corrosion is the most common corrosion form. Evaluating the performance of materials against uniform corrosion is of great guiding significance for understanding the corrosion resistance of materials and optimizing the material selection of related instruments and equipment.

[0003] Most of the existing corrosion testing equipment is in contact with the test piece. Either the test piece is suspended or placed in a container, and the test piece will come into contact with the container or fixed components, resulting in incomplete local corrosion, thus leading to low accuracy in the experimental evaluation of the metal corrosion rate.

[0004] Subsequently, a patent document with the publication number CN112461736B discloses a test equipment for evaluating the uniform corrosion of metal materials. This equipment passes alternating current through a suspended coil to generate eddy currents in the suspended coil, thereby suspending the test piece in the container, avoiding the problem of incomplete local corrosion caused by the contact between the test piece and the components. However, since eddy currents generate heat, a temperature control system is also set up in the text. However, due to the very rapid change in temperature, the performance requirements for the temperature control system are relatively high, which may lead to high device cost and excessive consumption. Moreover, during the corrosion process, the concentration of the solution gradually decreases, which is not considered in this application, and this will also affect the calculation of the corrosion rate.

[0005] Therefore, we propose an experimental device and method for testing the corrosion rate. Summary of the Invention

[0006] Aiming at the above deficiencies of the prior art, the present invention provides an experimental device and method for testing the corrosion rate.

[0007] To achieve the above invention object, the technical solution adopted by the present invention is as follows:

[0008] The invention discloses an experimental device for testing corrosion rate, which is used for carrying out corrosion experiment on spherical metal specimens. The experimental device comprises: a corrosion container, which is cylindrical and filled with a corrosion solution; a circulation pipeline, which is connected to the corrosion container and is used for circulating and extracting the corrosion solution in the corrosion container, and the circulation pipeline is drawn from the top of the corrosion container and fed into the bottom; a liquid spray suspension component, which is arranged at the feeding end of the circulation pipeline, and is used for spraying the corrosion solution in the circulation pipeline into the corrosion container, generating an upward thrust to suspend the spherical metal specimen in the corrosion solution; a liquid reserve component, which is arranged on the circulation pipeline and is used for monitoring the concentration of the corrosion solution and performing concentration regulation; and a controller, which is electrically connected to the liquid spray suspension component and the liquid reserve component.

[0009] By arranging a liquid spray suspension component on the circulation pipeline, the liquid spray suspension component sprays the corrosion solution from the bottom of the corrosion container during the circulation process. The thrust generated by the liquid spray suspension component lifts the spherical metal specimen, thereby avoiding the problem of incomplete local corrosion caused by long-term contact between the spherical metal specimen and other components, and improving the accuracy of the corrosion rate experiment. Compared with suspension based on the electromagnetic principle, this method will not cause the corrosion solution to heat up, reduces the temperature control device, reduces the complexity of the device, and directly realizes the suspension of the spherical metal specimen during the circulation of the corrosion solution through the circulation pipeline, and the structure is simpler while ensuring the effect.

[0010] It is further defined that the circulation pipeline includes a liquid pipe, the liquid inlet end of the liquid pipe is horizontally connected to the top side wall of the corrosion container, and the liquid outlet pipe is vertically connected to the bottom surface of the corrosion container, and a support frame is provided at the bottom of the corrosion container; the support frame can provide space for the installation of the circulation pipeline.

[0011] It is further defined that the liquid spray suspension assembly includes a liquid suction pump and a suspension nozzle, the liquid suction pump is connected to the liquid pipe and electrically connected to the controller, the suspension nozzle includes a main nozzle and an auxiliary nozzle, one end of the main nozzle is connected to the liquid outlet end of the liquid pipe, and the other end is connected to the bottom surface of the corrosion container, the auxiliary nozzle is provided with a plurality of auxiliary nozzles, and the plurality of auxiliary nozzles are circumferentially arranged around the main nozzle, the bottom ends of the plurality of auxiliary nozzles are connected to the pipe wall of the main nozzle, and the top ends are connected to the bottom surface of the corrosion container, and the inner diameter of the auxiliary nozzle is smaller than the inner diameter of the main nozzle.

[0012] By setting the main nozzle and the auxiliary nozzle, the inner diameter of the main nozzle is larger than the inner diameter of the auxiliary nozzle, so the spray pressure of the auxiliary nozzle will be higher than that of the main nozzle, and the spray height of the auxiliary nozzle will be higher. The auxiliary nozzle is arranged in a circumferential direction of the main nozzle, which can form a limit for the spherical metal specimen and prevent the spherical metal specimen from escaping from the range of the liquid column sprayed by the main nozzle and hitting the wall of the corrosion container during the continuous spraying of the main nozzle.

[0013] Further defined, the stock solution assembly includes a liquid storage container, a liquid outlet pipe, a concentration meter, and an opening and closing solenoid valve. The two ends of the liquid outlet pipe are respectively connected to the liquid outlet container and the liquid passing pipe. The concentration meter is connected to the liquid passing pipe near the liquid inlet end. The opening and closing solenoid valve is connected to the liquid outlet pipe and is electrically connected to the controller. By setting the concentration meter to detect the concentration of the corrosion solution passing through the liquid passing pipe (inlet pipe), if the concentration is too low, the controller opens the opening and closing solenoid valve, and the corrosion solution in the liquid storage container will enter the liquid passing pipe through the liquid outlet pipe and be pumped into the corrosion container together by the liquid extraction pump, so as to increase the concentration of the corrosion solution and keep it at the concentration required for the experiment.

[0014] Further defined, it also includes an infrared displacement module. The infrared displacement module is detachably arranged on the circumferential surface of the corrosion container and is used to monitor the height of the spherical metal specimen in the corrosion container. The infrared displacement module is also electrically connected to the controller. By setting the infrared displacement module to monitor the height of the spherical metal specimen, when the weight of the spherical metal specimen becomes smaller due to the corrosion of the corrosion solution, if the liquid extraction pump maintains the same pumping pressure, then the height of the spherical metal specimen will become higher and higher, affecting the stability of the experiment. Therefore, the infrared displacement module is used to monitor the height of the spherical metal specimen, and when the height is abnormal, the controller controls the pumping power of the liquid extraction pump to keep the height of the spherical metal specimen.

[0015] Further defined, the infrared displacement module includes a mounting bracket, an infrared emitter, and an infrared receiver. The corrosion container is a transparent container. The mounting bracket includes a U-shaped bracket, a fixed flexible disk, an adjusting flexible disk, a vertical rod, and a through-ring. The bracket includes a cross bar and vertical rods fixed at both ends of the cross bar. The fixed flexible disk and the adjusting flexible disk are arranged oppositely. The fixed flexible disk is fixed inside one vertical rod, and the adjusting flexible disk is threadedly connected to the other inner rod through a screw. The vertical rod is vertically arranged on the vertical rod, and the axis of the vertical rod and the axis of the fixed flexible disk are in the same vertical plane. The through-rings are vertically arranged at the top of the vertical rods, and the through-rings on the two vertical rods are parallel. The infrared emitter and the infrared receiver are respectively inserted into the two through-rings, and the infrared emitter and the infrared receiver are arranged oppositely.

[0016] Through the U-shaped bracket, the fixed flexible disk, and the adjusting flexible disk, the infrared displacement module can be clamped and fixed on the corrosion container at the same height as the spherical metal specimen, and the fixed flexible disk and the adjusting flexible disk can make the fitting degree with the corrosion container higher and the fixation more stable. At the beginning of the operation of the device, the infrared laser emitted by the infrared emitter is blocked by the spherical metal specimen assembly, and the infrared receiver does not receive the infrared laser signal. At this time, the device operates normally. When the spherical metal specimen is pushed to a higher height due to the reduction of its corrosion weight, the infrared receiver receives the infrared laser emitted by the infrared emitter, and the controller receives this signal, then controls the power of the liquid extraction pump to gradually decrease until the spherical metal specimen blocks the infrared laser again and stops adjusting the power of the liquid extraction pump. The structure is simple and easy to use.

[0017] Further defined, the included angle between the lower part of the auxiliary nozzle and the main nozzle is greater than 15 degrees and less than 60 degrees; setting the angle at the connection between the auxiliary nozzle and the main nozzle in this way is more conducive to the corrosive solution entering the auxiliary nozzle from the main nozzle.

[0018] A method for corrosion rate experiment, which conducts a corrosion rate experiment on a spherical metal specimen through the above experimental device for testing the corrosion rate, includes the following steps:

[0019] S1. The controller sets the pumping power of the liquid pump according to the weight and size of the spherical metal specimen to ensure that the corrosive solution ejected from the main nozzle can push up the spherical metal specimen;

[0020] S2. The controller starts the liquid pump and the infrared displacement module, then uses tools to place the spherical metal specimen at the liquid ejection top of the main nozzle in the corrosion container and starts timing. The corrosive solution ejected from the main nozzle makes the spherical metal specimen suspended in the corrosive solution;

[0021] S3. When the spherical metal specimen is corroded and its weight decreases over time, the suspension height of the spherical metal specimen increases. At this time, the spherical metal specimen disengages from the infrared displacement module, and the controller receives the signal sent by the infrared displacement module, controls the liquid pump to gradually reduce the power, and stops adjusting the power of the liquid pump when the spherical metal specimen remains in its original position;

[0022] S4. During the corrosion process, the concentration of the corrosive solution gradually decreases due to the consumption of the spherical metal specimen. At this time, the controller adds corrosive solution through the liquid preparation component to maintain the concentration required for corrosion;

[0023] S5. When the spherical metal specimen is completely corroded by the corrosive solution, stop timing to complete the experiment.

[0024] The beneficial effects of the present invention are as follows: By setting up a circulation pipeline and a liquid ejection suspension component, the spherical metal specimen is suspended in the corrosive solution by the thrust of the fluid, avoiding the problem of incomplete corrosion, and the structure is simpler compared with the electromagnetic eddy current suspension method, avoiding the problem that the corrosive solution affects the experimental results due to temperature changes. Description of the Drawings

[0025] Figure 1 Partial perspective view of the present invention from the front view perspective;

[0026] Figure 2 Top view of the mounting rack;

[0027] Figure 3 Top view of the suspension nozzle;

[0028] Figure 4 Connection diagram of the electrical components in the present invention.

[0029] The symbols of each component are as follows:

[0030] Spherical metal specimen 1, corrosion container 2, support frame 21, liquid blocking cover 22, circulation pipeline 3, liquid supply pipe 31, spray liquid suspension assembly 4, liquid extraction pump 41, suspension spray pipe 42, main spray pipe 421, auxiliary spray pipe 422, liquid preparation assembly 5, liquid storage container 51, liquid outlet pipe 52, concentration meter 53, on-off solenoid valve 54, infrared displacement module 6, mounting frame 61, support 611, fixed flexible disk 612, adjustable flexible disk 613, vertical rod 614, connecting ring 615, infrared emitter 62, infrared receiver 63, controller 7. Specific implementation manners

[0031] The specific implementation manners of the present invention will be described below to facilitate those skilled in the art of this technology to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation manners. For those of ordinary skill in the art of this technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

[0032] Embodiment:

[0033] As Figures 1-4As shown in the figure, an experimental device for testing the corrosion rate is used to conduct a corrosion experiment on a spherical metal specimen 1. The experimental device includes a corrosion container 2, a circulation pipeline 3, a liquid spraying and suspension assembly 4, a liquid preparation assembly 5, an infrared displacement module 6, and a controller 7; the corrosion container 2 is cylindrical, filled with a corrosion solution inside, the corrosion container 2 is a transparent container, and a support frame 21 is provided at the bottom of the corrosion container 2, and a liquid blocking cover 22 is provided at the top; the circulation pipeline 3 is used to circulate and extract the corrosion solution in the corrosion container 2, and the circulation pipeline 3 is drawn out from above the corrosion container 2 and fed in from the bottom; the circulation pipeline 3 includes a liquid passing pipe 31, the inlet end of the liquid passing pipe 31 is horizontally connected to the top side wall of the corrosion container 2, and the outlet pipe 52 is vertically connected to the bottom surface of the corrosion container 2; the liquid spraying and suspension assembly 4 is used to spray the corrosion solution in the circulation pipeline 3 into the corrosion container 2 and generate an upward thrust to suspend the spherical metal specimen 1 in the corrosion solution; the liquid spraying and suspension assembly 4 includes a liquid extraction pump 41 and a suspension spray pipe 42, the liquid extraction pump 41 is connected to the liquid passing pipe 31 and electrically connected to the controller 7, the suspension spray pipe 42 includes a main spray pipe 421 and auxiliary spray pipes 422, one end of the main spray pipe 421 is connected to the outlet end of the liquid passing pipe 31, and the other end is connected to the bottom surface of the corrosion container 2. There are multiple auxiliary spray pipes 422, and multiple auxiliary spray pipes 422 are arranged in a circumferential ring around the main spray pipe 421. The bottom ends of the multiple auxiliary spray pipes 422 are connected to the pipe wall of the main spray pipe 421, and the top ends are connected to the bottom surface of the corrosion container 2. The inner diameter of the auxiliary spray pipe 422 is smaller than that of the main spray pipe 421, and the included angle between the lower part of the auxiliary spray pipe 422 and the main spray pipe 421 is 30 degrees; the liquid preparation assembly 5 is arranged on the circulation pipeline 3 and is used to monitor the concentration of the corrosion solution and adjust the concentration; the liquid preparation assembly 5 includes a liquid storage container 51, an outlet pipe 52, a concentration meter 53, and an opening and closing solenoid valve 54. The two ends of the outlet pipe 52 are respectively connected to the outlet container and the liquid passing pipe 31. The concentration meter 53 is connected to the liquid passing pipe 31 near the inlet end, and the opening and closing solenoid valve 54 is connected to the outlet pipe 52 and electrically connected to the controller 7; the infrared displacement module 6 is detachably arranged on the circumferential surface of the corrosion container 2 and is used to monitor the height of the spherical metal specimen 1 in the corrosion container 2; the infrared displacement module 6 includes a mounting bracket 61, an infrared transmitting head 62, and an infrared receiving head 63; the mounting bracket 61 includes a U-shaped bracket 611, a fixed flexible disk 612, an adjusting flexible disk 613, a vertical rod 614, and a through-ring 615;The bracket 611 includes a cross bar and longitudinal bars fixedly arranged at both ends of the cross bar. The fixed flexible disk 612 and the adjustable flexible disk 613 are arranged oppositely. The fixed flexible disk 612 is fixedly arranged inside one longitudinal bar, and the adjustable flexible disk 613 is threadedly connected to the other inner bar through a screw. The vertical rod 614 is vertically arranged on the longitudinal bar, and the axis of the vertical rod 614 and the axis of the fixed flexible disk 612 are in the same vertical plane. The through-ring 615 is vertically arranged at the top of the vertical rod 614, and the through-rings 615 on the two vertical rods 614 are arranged in parallel. The infrared emitter 62 and the infrared receiver 63 are respectively arranged inside the two through-rings 615, and the infrared emitter 62 and the infrared receiver 63 are arranged oppositely; The controller 7 is electrically connected to the liquid extraction pump 41, the concentration meter 53, the on-off solenoid valve 54, and the infrared displacement module 6.

[0034] By arranging a liquid spray suspension component 4 on the circulation pipeline 3, the liquid spray suspension component 4 sprays the corrosion solution from the bottom of the corrosion container 2 during the circulation process, and the thrust generated by the liquid spray suspension component 4 lifts the spherical metal specimen 1, thereby avoiding the problem of incomplete local corrosion caused by the long-term contact between the spherical metal specimen 1 and other components, and improving the accuracy of the corrosion rate experiment. Compared with the suspension based on the electromagnetic principle, this method will not cause the corrosion solution to heat up, reduce the temperature control device, reduce the complexity of the device, and directly realize the suspension of the spherical metal specimen 1 during the circulation of the corrosion solution through the circulation pipeline 3, and the structure is simpler while ensuring the effect; the support frame 21 is provided for the installation of the circulation pipeline 3 Provide space; by setting the main nozzle 421 and the auxiliary nozzle 422, the inner diameter of the main nozzle 421 is larger than the inner diameter of the auxiliary nozzle 422, so the spray pressure of the auxiliary nozzle 422 will be higher than that of the main nozzle 421, and the spray height of the auxiliary nozzle 422 will be higher. The auxiliary nozzle 422 is arranged in a circle on the circumference of the main nozzle 421, which can form a limit for the spherical metal test piece 1 to prevent the spherical metal test piece 1 from escaping from the range of the sprayed liquid column of the main nozzle 421 and hitting the wall of the corrosion container 2 during the continuous spraying of the main nozzle 421; by setting a concentration meter 53 to detect the concentration of the corrosive solution passing through the liquid inlet pipe of the liquid passage pipe 31, if the concentration is too low, the controller 7 opens the on-off solenoid valve 54, and the corrosion container 2 in the liquid storage container 51 will enter the liquid passage through the liquid outlet pipe 52 to the liquid passage. The liquid in the liquid pipe 31 is pumped into the corrosion container 2 by the liquid pump 41, thereby increasing the concentration of the corrosion solution and keeping it at the concentration required by the experiment; the height of the spherical metal specimen 1 is monitored by setting the infrared displacement module 6. When the corrosion weight of the spherical metal specimen 1 due to the corrosion solution becomes smaller and smaller, if the liquid pump 41 maintains the same liquid pumping pressure, the height of the spherical metal specimen 1 will become higher and higher, affecting the stability of the experiment. Therefore, the height of the spherical metal specimen 1 is monitored by the infrared displacement module 6. When the height is abnormal, the controller 7 controls the liquid pumping power of the liquid pump 41 to maintain the height of the spherical metal specimen 1; the infrared displacement module 6 can be clamped and fixed on the corrosion container 2 by the U-shaped bracket 611, the fixed floppy disk 612 and the adjustable floppy disk 613. The position on the corrosion container 2 is at the same height as the spherical metal specimen 1, and the fixed floppy disk 612 and the adjustable floppy disk 613 can make the fit with the corrosion container 2 higher and the fixation more stable. At the beginning of the operation of the device, the infrared laser emitted by the infrared transmitting head 62 is blocked by the spherical metal specimen 1, and the infrared receiving head 63 does not receive the infrared laser signal. At this time, the device operates normally. When the spherical metal specimen 1 is pushed to a higher height due to the lightening of the corrosion weight, the infrared receiving head 63 receives the infrared laser emitted by the infrared transmitting head 62. The controller 7 receives the signal and controls the power of the liquid pump 41 to gradually decrease until the spherical metal specimen 1 blocks the infrared laser again, and stops adjusting the power of the liquid pump 41. The structure is simple and easy to use.Setting the angle at the connection between the secondary nozzle 422 and the primary nozzle 421 in this way is more conducive to the corrosive solution entering the secondary nozzle 422 from the primary nozzle 421.

[0035] In the present invention, the cross-sectional area A of the nozzle opening of the primary nozzle satisfies:

[0036]

[0037] where ρ is the density of the corrosive solution and v is the flow velocity at the nozzle opening of the primary nozzle.

[0038] Meanwhile, in this application, the controller 7 uses an STM32 series chip, the concentration meter 53 uses a Fuji FUJI FUD-1 Model-12 / 1006 ultrasonic concentration meter, the on-off solenoid valve 54 uses a DN20 brass solenoid valve, the liquid extraction pump 41 uses a WPM-2020S peristaltic pump, and the infrared displacement module 6 uses an HS0038B infrared laser emission and reception set.

[0039] A method for corrosion rate experiment, which conducts a corrosion rate experiment on a spherical metal specimen through the above experimental device for testing the corrosion rate, includes the following steps:

[0040] S1. The controller 7 sets the liquid extraction power of the liquid extraction pump 41 according to the weight and size of the spherical metal specimen 1 to ensure that the corrosive solution ejected from the primary nozzle 421 can push up the spherical metal specimen 1;

[0041] S2. The controller 7 starts the liquid extraction pump 41 and the infrared displacement module 6, then uses a tool to place the spherical metal specimen 1 at the liquid ejection top of the primary nozzle 421 in the corrosion container 2 and starts timing. The corrosive solution ejected from the primary nozzle 421 makes the spherical metal specimen 1 suspended in the corrosive solution;

[0042] S3. When the spherical metal specimen 1 is corroded and its weight decreases over time, the suspension height of the spherical metal specimen 1 increases. At this time, the spherical metal specimen 1 disengages from the infrared displacement module 6. The controller 7 receives the signal sent by the infrared displacement module 6 and controls the liquid extraction pump 41 to gradually reduce the power until the spherical metal specimen 1 is kept in the original position and then stops adjusting the power of the liquid extraction pump 41;

[0043] S4. During the corrosion process, the concentration of the corrosive solution gradually decreases due to the consumption of the spherical metal specimen 1. At this time, the controller 7 adds the corrosive solution through the liquid preparation component 5 to maintain the concentration required for corrosion;

[0044] S5. Stop timing when the spherical metal specimen 1 is completely corroded by the corrosive solution to complete the experiment.

Claims

1. An experimental device for testing the corrosion rate, which is used to conduct a corrosion experiment on a spherical metal specimen (1), and is characterized in that, The experimental device includes: A corrosion container (2), which is cylindrical and filled with a corrosion solution inside; A circulation pipeline (3), which is connected to the corrosion container (2) and is used to circulate and extract the corrosion solution in the corrosion container (2), and the circulation pipeline (3) is drawn out from above the corrosion container (2) and fed into the bottom; A liquid spraying and suspension assembly (4), which is arranged at the feeding end of the circulation pipeline (3), and the liquid spraying and suspension assembly (4) is used to spray the corrosion solution in the circulation pipeline (3) into the corrosion container (2) to generate an upward thrust to suspend the spherical metal specimen (1) in the corrosion solution; A liquid preparation assembly (5), which is arranged on the circulation pipeline (3) and is used to monitor the concentration of the corrosion solution and adjust the concentration; A controller (7), which is electrically connected to the liquid spraying and suspension assembly (4) and the liquid preparation assembly (5).

2. The experimental device for testing the corrosion rate according to claim 1, wherein, The circulation pipeline (3) includes a liquid passing pipe (31), the liquid inlet end of the liquid passing pipe (31) is horizontally connected to the top side wall of the corrosion container (2), and the liquid outlet pipe (52) is vertically connected to the bottom surface of the corrosion container (2). A support frame (21) is arranged at the bottom of the corrosion container (2).

3. The experimental device for testing the corrosion rate according to claim 2, characterized in that, The liquid spraying and suspension assembly (4) includes a liquid extraction pump (41) and a suspension spray pipe (42). The liquid extraction pump (41) is connected to the liquid passing pipe (31) and is electrically connected to the controller (7). The suspension spray pipe (42) includes a main spray pipe (421) and auxiliary spray pipes (422). One end of the main spray pipe (421) is connected to the liquid outlet end of the liquid passing pipe (31), and the other end is connected to the bottom surface of the corrosion container (2). There are multiple auxiliary spray pipes (422), and multiple auxiliary spray pipes (422) are arranged in a circumferential ring around the main spray pipe (421). The bottom ends of the multiple auxiliary spray pipes (422) are connected to the pipe wall of the main spray pipe (421), and the top ends are connected to the bottom surface of the corrosion container (2). The inner diameter of the auxiliary spray pipe (422) is smaller than the inner diameter of the main spray pipe (421).

4. The experimental device for testing the corrosion rate according to claim 3, characterized in that, The liquid preparation assembly (5) includes a liquid storage container (51), a liquid outlet pipe (52), a concentration meter (53) and an opening and closing solenoid valve (54). The two ends of the liquid outlet pipe (52) are respectively connected to the liquid outlet container and the liquid passing pipe (31). The concentration meter (53) is connected to the liquid passing pipe (31) near the liquid inlet end. The opening and closing solenoid valve (54) is connected to the liquid outlet pipe (52) and is electrically connected to the controller (7).

5. The experimental device for testing the corrosion rate according to claim 4, characterized in that, It also includes an infrared displacement module (6), which is detachably arranged on the circumferential surface of the corrosion container (2) and is used to monitor the height of the spherical metal specimen (1) in the corrosion container (2). The infrared displacement module (6) is also electrically connected to the controller (7).

6. The experimental device for testing the corrosion rate according to claim 5, characterized in that, The infrared displacement module (6) includes a mounting bracket (61), an infrared emitter (62) and an infrared receiver (63); the corrosion container (2) is a transparent container, and the mounting bracket (61) includes a U-shaped bracket (611), a fixed flexible disk (612), an adjustable flexible disk (613), a vertical rod (614) and a through-ring (615); the bracket (611) includes a cross bar and vertical bars fixedly provided at both ends of the cross bar, the fixed flexible disk (612) and the adjustable flexible disk (613) are arranged oppositely, the fixed flexible disk (612) is fixedly provided inside one of the vertical bars, the adjustable flexible disk (613) is threadedly connected to the other inner rod by a screw, the vertical rod (614) is vertically provided on the vertical bar, and the axis of the vertical rod (614) and the axis of the fixed flexible disk (612) are in the same vertical plane, the through-ring (615) is vertically provided at the top of the vertical rod (614), and the through-rings (615) on the two vertical rods (614) are arranged in parallel, the infrared emitter (62) and the infrared receiver (63) are respectively inserted into the two through-rings (615), and the infrared emitter (62) and the infrared receiver (63) are arranged oppositely.

7. The experimental device for testing the corrosion rate according to claim 6, wherein, The included angle between the lower part of the auxiliary nozzle (422) and the main nozzle (421) is greater than 15 degrees and less than 60 degrees.

8. An experimental method for corrosion rate, which conducts a corrosion rate experiment on a spherical metal specimen by using the experimental device for testing corrosion rate as described in claim 7, is characterized in that Including the following steps: S1. The controller (7) sets the pumping power of the liquid pumping pump (41) according to the weight and size of the spherical metal specimen (1) to ensure that the corrosion solution ejected from the main nozzle (421) can push up the spherical metal specimen (1). S2. The controller (7) starts the liquid pumping pump (41) and the infrared displacement module (6), and then uses a tool to place the spherical metal specimen (1) at the liquid ejection top of the main nozzle (421) in the corrosion container (2) and starts timing. The corrosion solution ejected from the main nozzle (421) makes the spherical metal specimen (1) suspended in the corrosion solution. S3. When the spherical metal specimen (1) is corroded and its weight decreases over time, the suspension height of the spherical metal specimen (1) increases. At this time, the spherical metal specimen (1) disengages from the infrared displacement module (6). The controller (7) receives the signal sent by the infrared displacement module (6) and controls the liquid pumping pump (41) to gradually reduce the power until the spherical metal specimen (1) is kept in its original position and then stops adjusting the power of the liquid pumping pump (41). S4. During the corrosion process, the concentration of the corrosion solution gradually decreases due to the consumption of the spherical metal specimen (1). At this time, the controller (7) adds corrosion solution through the liquid preparation assembly (5) to maintain the required concentration for corrosion. S5. When the spherical metal specimen (1) is completely corroded by the corrosion solution, stop timing to complete the experiment.

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