U-shaped sample preparation device

Abstract

The invention provides a U-shaped sample preparation device, and belongs to the technical field of stress corrosion testing, the U-shaped sample preparation device comprises a support seat, a base station and a pressure applying assembly. The base table is fixed on the supporting seat, the base table is provided with an embedding groove, a U-shaped groove and rotating shafts, the U-shaped groove is communicated with the embedding groove, the depth of the U-shaped groove is larger than that of the embedding groove, the extending direction of the embedding groove is perpendicular to that of the U-shaped groove, the rotating shafts are rotationally arranged in the base table, the rotating shafts are located on the two sides of the U-shaped groove, the rotating shafts and the U-shaped groove extend in the same direction, and the rotating shafts penetrate through the junction of the embedding groove and the U-shaped groove; the pressure applying assembly comprises a transmission mechanism and a pressure head, the transmission mechanism is fixed to the supporting base, the pressure head is connected to the transmission mechanism, and the transmission mechanism drives the pressure head to move in the height direction. According to the preparation device disclosed by the invention, two arms of the U-shaped sample formed by pressing and bending can be kept parallel and centered, the surface of the sample is not damaged, and related experimental standard requirements of the U-shaped sample in a stress corrosion experiment are met.

Description

Technical Field

[0001] The present invention relates to the technical field of stress corrosion testing, and particularly to a U-shaped specimen preparation device. Background Art

[0002] The stress corrosion test aims to evaluate the corrosion resistance of materials in a specific environment, especially the stress corrosion resistance after welding or heat treatment, and to determine whether the material is prone to stress corrosion in a specific corrosive medium.

[0003] The U-bending test is a commonly used constant strain stress corrosion test method. This method has the advantages of simple test, compact specimen, and batch synchronous operation, and is very suitable for use in factories and laboratories. Its main process is to process a long rectangular metal sheet into a U shape and fix it with bolts, and then place the specimen in a specific environmental medium and expose it for a specified period. Then, according to whether the specimen cracks, it is determined whether the metal is sensitive to stress corrosion cracking in a specific environment, or according to the length of time when cracks appear, the difference in stress corrosion sensitivity of different materials in a specific environment is judged.

[0004] Currently, U-shaped specimens usually adopt the preparation method described in the national standard GB / T15970.3 - 1995. This preparation method is prone to problems such as inaccurate alignment of the two arms or inaccurate force application position during specimen preparation, resulting in the two arms of the prepared U-shaped specimen being non-parallel and asymmetric after bending, or the U-shaped opening being too large, and unable to apply the corresponding stress by installing bolts and nuts and tightening, so that the U-shaped specimen cannot meet the requirements for stress corrosion specimen preparation.

[0005] Therefore, it is necessary to provide a U-shaped specimen preparation device to solve the above technical problems. Summary of the Invention

[0006] In view of the above problems existing in the prior art, the present invention provides a U-shaped specimen preparation device to improve the problems of inaccurate alignment of the two arms and inaccurate force application position during the preparation of existing U-shaped specimens.

[0007] To achieve the above object and other related objects, the present invention provides a U-shaped specimen preparation device, which includes a support base, a base table, and a pressing assembly.

[0008] Among them, the base is fixed on the support seat. An embedding groove, a U-shaped groove and a rotating shaft are provided on the base. The U-shaped groove communicates with the embedding groove. The depth of the U-shaped groove is greater than that of the embedding groove. The embedding groove extends in a first direction, and the U-shaped groove extends in a second direction. The first direction is perpendicular to the second direction. The rotating shaft is rotatably arranged in the base. The rotating shaft is located on both sides of the U-shaped groove and extends along the second direction and passes through the junction of the embedding groove and the U-shaped groove. The pressing assembly includes a transmission mechanism and a pressing head. The transmission mechanism is fixed on the support seat and is located above the base. The pressing head is connected to the transmission mechanism. The transmission mechanism drives the pressing head to move in the height direction. The projection of the pressing head in the height direction is located in the communication area between the U-shaped groove and the embedding groove.

[0009] In an example of the present invention, the rotating shaft has an end extending out of the outside of the base. An elastic member is provided between the end and the base or the support seat. The elastic member is used to drive the rotating shaft to rotate and reset.

[0010] In an example of the present invention, a clamping portion is provided on the end. The clamping portion extends outward in the radial direction of the rotating shaft. One end of the elastic member is connected to the clamping portion, and the other end of the elastic member is connected to the base or the support seat.

[0011] In an example of the present invention, the support seat includes a base and a support frame. The support frame is provided on the base. The base is fixed on the base, and the pressing assembly is provided on the support frame.

[0012] In an example of the present invention, the U-shaped sample preparation device further includes a controller, and the controller is communicatively connected to the transmission mechanism.

[0013] In an example of the present invention, the transmission mechanism can also drive the pressing head to move in the first direction. The U-shaped sample preparation device further includes a laser sensor. The laser sensor is fixed above the base. The laser sensor respectively collects image information at both ends of the embedding groove and the communication area between the embedding groove and the U-shaped groove. The laser sensor is communicatively connected to the controller.

[0014] In an example of the present invention, a six-axis force sensor is provided between the pressing head and the drive shaft of the driving mechanism. The six-axis force sensor is communicatively connected to the controller.

[0015] In an example of the present invention, a gasket is provided on the surface of the groove body of the embedding groove. The gasket includes a rubber layer and a carbon fiber layer. The rubber layer is provided on the surface of the groove body of the embedding groove, and the carbon fiber layer is provided on the rubber layer.

[0016] In an example of the present invention, the shape of the indenter is U-shaped, and the radius of curvature of the indenter is proportional to the elastic modulus and yield strength of the sample material to be formed.

[0017] In an example of the present invention, a scale ruler is further provided on the base, and the scale ruler is located on one side of the groove and extends in the same direction as the groove.

[0018] The U-shaped sample preparation device of the present invention can apply a force to the center position of the sample by the indenter, and use the U-shaped groove to shape the sample, thereby ensuring uniform force when the sample is bent, and enabling the two arms of the U-shaped sample formed by pressing and bending to be parallel and centered, and the surface of the sample is not damaged, meeting the relevant experimental standard requirements of the U-shaped sample for stress corrosion experiments. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other embodiments can be obtained based on these drawings.

[0020] Figure 1 Schematic structural diagram of the U-shaped sample preparation device in an embodiment of the present invention;

[0021] Figure 2 Front view of the structure of the U-shaped sample preparation device in an embodiment of the present invention;

[0022] Figure 3 Schematic diagram of the cooperation structure between the indenter and the base in an embodiment of the present invention;

[0023] Figure 4 Schematic diagram of the working process of the U-shaped sample preparation device in an embodiment of the present invention;

[0024] Figure 5 Schematic diagram of the process of pressing the sample to be formed into a U-shaped sample in an embodiment of the present invention;

[0025] Figure 6 Schematic diagram of the process of extruding and sample preparation by multi-sensor hybrid control of the U-shaped sample preparation device in an embodiment of the present invention.

[0026] Description of Component Labels

[0027] 100. Support base; 110. Base; 120. Support frame; 200. Base platform; 210. Embedded groove; 220. U-shaped groove; 230. Rotating shaft; 231. Mounting part; 240. Elastic part; 250. Scale ruler; 300. Pressing assembly; 310. Transmission mechanism; 311. Driving shaft; 320. Pressing head; 330. Six-axis force sensor; 400. Controller; 510. Laser displacement sensor; 520. First positioning sensor; 530. Second positioning sensor; 600. Sample to be formed. Detailed implementation manners

[0028] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. It should also be understood that the terms used in the embodiments of the present invention are for describing specific specific implementation manners, rather than for limiting the protection scope of the present invention. The test methods without specific conditions noted in the following embodiments are usually in accordance with conventional conditions or in accordance with the conditions recommended by each manufacturer.

[0029] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of clear narration, rather than for limiting the scope in which the present invention can be implemented. The change or adjustment of their relative relationships, without substantial change in technical content, should also be regarded as the scope in which the present invention can be implemented.

[0030] Please refer to Figure 1 , the present invention provides a U-shaped sample preparation device, which can, during the process of preparing a U-shaped sample, use the cooperation of the embedded groove and the U-shaped groove to symmetrically place the two arms of the sample to be formed above the U-shaped groove. At the same time, during the process of pressing the sample to be formed by the pressing head, use the U-shaped groove and the rotating shafts on both sides of the U-shaped groove to apply symmetric and uniform deformation forces to the two arms of the sample to be formed, so that the sample to be formed is shaped into a U-shaped sample.

[0031] Please see Figures 1 to 5 , the U-shaped sample preparation device includes a support base 100, a base platform 200 and a pressing assembly 300.

[0032] As Figures 1 to 3As shown, the base 200 is fixed on the support base 100. An embedding groove 210, a U-shaped groove 220 and a rotating shaft 230 are provided on the base 200. The embedding groove 210 and the U-shaped groove 220 are arranged on the top surface of the base 200. The embedding groove 210 is used to place and fix the sample 600 to be formed. The U-shaped groove 220 communicates with the embedding groove 210, and the depth of the U-shaped groove 220 is greater than that of the embedding groove 210. On the base 200, the embedding groove 210 extends in a first direction, and the U-shaped groove 220 extends in a second direction. The first direction is perpendicular to the second direction, so that when the sample 600 to be formed in the embedding groove 210 is pressured and deformed, the two end arms thereof can be symmetrically stressed in opposite directions under the shaping action of the U-shaped groove 220, so that the two arms of the formed U-shaped specimen are aligned. The rotating shaft 230 is rotatably installed in the base 200, and the rotating shaft 230 is located on both sides of the groove body of the U-shaped groove 220. The rotating shaft 230 extends in the second direction and passes through the junction of the embedding groove 210 and the U-shaped groove 220. Part of the area of the rotating shaft 230 is simultaneously exposed in the U-shaped groove 220 and the embedding groove 210. Since the rotating shaft 230 is located on both sides of the U-shaped groove 220 and at the bottom of the embedding groove 210, the sample 600 to be formed placed in the embedding groove 210 can contact the top of the rotating shaft 230. When the sample 600 to be formed is pressured, the rotating shaft 230 can provide a bending force in the normal direction for the sample 600 to be formed at the contact position, so as to guide the sample 600 to be formed to smoothly enter the U-shaped groove 220. It should be noted that the size of the U-shaped groove 220 can be adaptively adjusted according to the radius size and bending angle of the U-shaped specimen required by the experiment.

[0033] As Figures 1 to 3 shown, the pressing assembly 300 includes a transmission mechanism 310 and a pressing head 320. The transmission mechanism 310 is fixed on the support base 100 and is located above the base 200. A driving shaft 311 is provided at the bottom of the transmission mechanism 310. The pressing head 320 is connected to the driving shaft 311. The transmission mechanism 310 drives the pressing head 320 to move in the height direction by controlling the expansion and contraction of the driving shaft 311. Among them, the projection of the pressing head 320 in the height direction is located in the communication area between the U-shaped groove 220 and the embedding groove 210. The transmission mechanism 310 can drive the pressing head 320 to move towards the base 200 side, so as to press the sample 600 to be formed placed in the embedding groove 210.

[0034] As Figures 3 to 5As shown in the figure, the specific process of preparing a U-shaped specimen by the U-shaped specimen preparation device is as follows: Place the sample 600 to be formed in the slot 210, and align the middle position of the sample 600 to be formed with the U-shaped groove 220; The transmission mechanism 310 drives the indenter 320 to move towards the base 200 along the height direction, and presses the sample 600 to be formed after contacting it, so that the sample to be measured undergoes a bending deformation under the guidance of the bottom rotating shaft 230 to enter the U-shaped groove 220. When the sample 600 to be formed completely enters the U-shaped groove 220, the transmission mechanism 310 stops pressing the sample 600 to be formed. At this time, the sample 600 to be formed is shaped into a U-shaped specimen by the U-shaped groove 220.

[0035] As Figures 1 to 3 shown, in some embodiments, the support base 100 includes a base 110 and a support frame 120. The support frame 120 is arranged on the base 110, and an open cavity is formed between the support frame 120 and the base 110. The base 200 is fixed on the base 110 and is located in the open cavity. The pressing assembly 300 is fixed on the support frame 120, the transmission mechanism 310 is fixed on the top of the support frame 120, the drive shaft 311 of the transmission mechanism 310 extends from the top of the support frame 120 into the open cavity, and the indenter 320 is connected to the drive shaft 311.

[0036] As Figure 3 and Figure 4 shown, in some embodiments, the rotating shaft 230 has an end extending outside the base 200, and an elastic member 240 is arranged between this end and the base 200 or the support base 100. One end of the top of the elastic member 240 is fixed on the rotating shaft 230, and one end of the bottom of the elastic member 240 is fixed on the base 200 or the support base 100. The elastic member 240 can store energy when the rotating shaft 230 leaves the initial position to guide the sample 600 to be formed into the U-shaped groove 220, and when the indenter 320 stops squeezing the sample 600 to be formed, it can drive the rotating shaft 230 to rotate back to the initial position through its own elastic deformation. The rotating shaft 230 that rotates back to the initial position can take out the formed U-shaped specimen from the U-shaped groove 220, so as to prevent the formed U-shaped specimen from being stuck in the U-shaped groove 220 due to its own elastic deformation and being difficult to take out, thus wasting the sample preparation time.

[0037] As Figure 3 and Figure 4 shown, in some embodiments, a clamping portion 231 is arranged on the rotating shaft 230. The clamping portion 231 is located at the end of the rotating shaft 230 extending outside the base 200. The clamping portion 231 extends radially outward from the outer edge of the end. One end of the top of the elastic member 240 is sleeved and fixed on the clamping portion 231, and one end of the bottom of the elastic member 240 is connected to the base 200 or the support base 100. For example, one end of the bottom of the elastic member 240 is connected to the fixing ring on the base 110.

[0038] As Figures 1 to 4 shown, in some embodiments, the U-shaped specimen preparation device further includes a controller 400. The controller 400 is communicatively connected to the transmission mechanism 310. The controller 400 is configured to control the extrusion process of the transmission mechanism 310 on the sample 600 to be formed on the base 200.

[0039] As Figures 1 to 4 shown, in some embodiments, a six-axis force sensor 330 is disposed between the indenter 320 and the drive shaft 311 of the transmission mechanism 310. The six-axis force sensor 330 is communicatively connected to the controller 400. The six-axis force sensor 330 real-time monitors the stress distribution generated when the indenter 320 presses on the sample 600 to be formed. The controller 400 receives the stress distribution collected by the six-axis force sensor 330, and when the stress distribution is uneven, adjusts the pressure applied by the indenter 320 to the sample 600 to be formed by controlling the transmission mechanism 310, so as to balance the distribution of the stress applied by the indenter 320 to the sample 600 to be formed. For example, when the stress concentration occurs on the bending side of the sample 600 to be formed, the local stress gradient of the sample 600 to be formed is relatively large. The controller 400 performs pressure adjustment on the driving device (such as a hydraulic valve) in the transmission mechanism 310 to perform fuzzy compensation on the stress applied to the indenter 320, thereby realizing the balance of the stress distribution applied by the indenter 320 to the sample 600 to be formed.

[0040] As Figure 3 shown, in some embodiments, a scale ruler 250 is further disposed on the base 200. The scale ruler 250 is located on one side of the groove 210 and extends along the first direction in the same way as the groove 210. When the sample 600 to be formed is placed in the groove 210, the scale ruler 250 helps to locate the positions of both ends of the sample 600 to be formed in the groove 210, so that the central position of the sample 600 to be formed coincides with the central axis of the U-shaped groove 220.

[0041] As Figures 1 to 4 shown, in some embodiments, the U-shaped specimen preparation device further includes a laser sensor. The laser sensor is fixedly located above the base 200. The laser sensor is communicatively connected to the controller 400. The laser sensor respectively collects the image information of both ends of the groove 210 and the communication area between the groove 210 and the U-shaped groove 220. Among them, the laser sensor includes a laser displacement sensor 510, a first positioning sensor 520, and a second positioning sensor 530. The laser displacement sensor 510 is fixed on the indenter 320 or the drive shaft 311 of the transmission mechanism 310. The laser displacement sensor 510 is aligned with the communication area between the groove 210 and the U-shaped groove 220. The first positioning sensor 520 and the second positioning sensor 530 are fixed on the support frame 120. The detection ends of the first positioning sensor 520 and the second positioning sensor 530 face the base 200 side and are respectively aligned with both ends of the groove 210.

[0042] Moreover, the transmission mechanism 310 can also drive the indenter 320 to move along the first direction in which the slot 210 extends. When the sample 600 to be formed is symmetrically placed in the slot 210 with reference to the scale 250 relative to the U-shaped groove 220, the laser displacement sensor 510 collects an image of the region where the slot 210 communicates with the U-shaped groove 220, and the first positioning sensor 520 and the second positioning sensor 530 respectively collect images of the regions where the two ends of the sample 600 to be formed are located. The first positioning sensor 520 and the second positioning sensor 530 finely determine the relative positions of the two ends of the sample 600 to be formed in the slot 210 based on the scale coordinates at which the two ends of the sample 600 to be formed are aligned with the scale 250 in the collected images, and the laser displacement sensor 510 determines the scale coordinates of the region aligned with the indenter 320 based on the collected images. The controller 400 adjusts the lateral position of the indenter 320 in the first direction through the transmission mechanism 310 based on the scale coordinates of the two ends of the formed sample and the scale coordinates of the region aligned with the indenter 320, so that the central axis of the indenter 320 coincides with the center of the sample 600 to be formed. Moreover, during the subsequent process of the transmission mechanism 310 driving the indenter 320 to extrude the sample 600 to be formed, the laser displacement sensor 510 still collects the surface image of the sample 600 to be formed in real time to monitor the surface deformation of the sample 600 to be formed during the extrusion process. The controller 400 determines whether the indenter 320 presses on the central position of the sample 600 to be formed based on the image collected by the laser displacement sensor 510, and adjusts the position of the indenter 320 in the first direction based on the determination, so that the center line of the indenter 320 always coincides with the central position of the sample to be measured, thereby ensuring that the two arms of the U-shaped specimen are symmetric and parallel. For example, in one example, during the extrusion of the sample 600 to be formed, the laser displacement sensor 510 monitors the bending condition of the sample 600 to be formed in real time. When the bending deviation of the two arms of the sample 600 to be formed exceeds ±1 mm, the bending deviation is corrected during the subsequent extrusion process by adjusting the position of the indenter 320 in the first direction.

[0043] In addition, as Figure 6 shown, in some embodiments, the U-shaped specimen preparation device can adopt a hybrid control method of detecting information by multiple sensors. When the controller 400 controls the indenter 320 to extrude the sample 600 to be formed through the transmission mechanism 310, it monitors and adjusts the stress distribution and deformation condition of the sample 600 to be formed in real time.

[0044] As Figure 3As shown, in some embodiments, a gasket is provided on the surface of the groove body of the groove 210. The gasket can protect the surface of the sample 600 to be formed during the pressing and forming process, effectively preventing the surface of the sample 600 from being scratched due to friction between the sample 600 to be formed and the groove 210 during the extrusion process, and ensuring that the surface of the U-shaped specimen formed meets the sample preparation requirements. In one example, the gasket includes a rubber layer and a carbon fiber layer. The rubber layer is provided on the surface of the groove body of the groove 210, and the carbon fiber layer is provided on the rubber layer.

[0045] In addition, in some embodiments, the shape of the indenter 320 is U-shaped, and the radius of curvature of the indenter 320 can be adaptively adjusted based on the material of the sample 600 to be formed. Among them, the radius of curvature R of the indenter 320 is proportional to the elastic modulus K and the yield strength σ of the material of the sample 600 to be formed 0.2 For example, the radius of curvature R of the indenter 320 can be R = K×σ 0.2 .

[0046] In summary, the U-shaped specimen preparation device of the present invention can apply force to the center position of the specimen by the indenter, and use the U-shaped groove to shape the sample, thereby ensuring uniform force on the sample during bending, and enabling the two arms of the U-shaped specimen formed by pressing and bending to be parallel and centered, and the surface of the specimen is not damaged, meeting the relevant experimental standard requirements of the U-shaped specimen for stress corrosion experiments.

[0047] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A U-shaped sample preparation device, characterized in that: include: Support seat; A base, the base is fixed on the support seat, the base is provided with an embedding groove, a U-shaped groove and a rotating shaft, the U-shaped groove is connected with the embedding groove, the depth of the U-shaped groove is greater than the depth of the embedding groove, the embedding groove extends along a first direction, the U-shaped groove extends along a second direction, the first direction is perpendicular to the second direction, the rotating shaft is rotatably arranged in the base, the rotating shaft is located on both sides of the U-shaped groove, the rotating shaft extends along the second direction and passes through the junction of the embedding groove and the U-shaped groove; A pressure-applying assembly, the pressure-applying assembly comprising a transmission mechanism and a pressure head, the transmission mechanism being fixed on the support seat and located above the base, the pressure head being connected to the transmission mechanism, the transmission mechanism driving the pressure head to move in the height direction, the projection of the pressure head in the height direction being located in the connecting area between the U-shaped groove and the embedding groove.

2. The U-shaped sample preparation device according to claim 1, characterized in that: The rotating shaft has an end portion extending outward from the base, and an elastic member is arranged between the end portion and the base or the support seat, and the elastic member is used to drive the rotating shaft to rotate and reset.

3. The U-shaped sample preparation device according to claim 2, characterized in that: A clamping portion is provided on the end portion, and the clamping portion extends outwardly along the radial direction of the rotating shaft. One end of the elastic member is connected to the clamping portion, and the other end of the elastic member is connected to the base or the support seat.

4. The U-shaped sample preparation device according to claim 1, characterized in that: The support seat comprises a base and a support frame, the support frame is arranged on the base, the base is fixed on the base, and the pressure assembly is arranged on the support frame.

5. The U-shaped sample preparation device according to claim 1 or 4, characterized in that: The U-shaped sample preparation device also includes a controller, and the controller is communicatively connected with the transmission mechanism.

6. The U-shaped sample preparation device according to claim 5, characterized in that: The transmission mechanism can also drive the pressure head to move along the first direction. The U-shaped sample preparation device also includes a laser sensor, which is fixed above the base. The laser sensor collects image information of both ends of the embedding groove and the connecting area between the embedding groove and the U-shaped groove respectively. The laser sensor is communicatively connected to the controller.

7. The U-shaped sample preparation device according to claim 5, characterized in that: A six-dimensional force sensor is arranged between the pressure head and the driving shaft of the driving mechanism, and the six-dimensional force sensor is communicatively connected with the controller.

8. The U-shaped sample preparation device according to claim 1, characterized in that: A liner is arranged on the surface of the groove body of the embedding groove. The liner comprises a rubber layer and a carbon fiber layer. The rubber layer is arranged on the surface of the groove body of the embedding groove, and the carbon fiber layer is arranged on the rubber layer.

9. The U-shaped sample preparation device according to claim 1, characterized in that: The shape of the pressing head is U-shaped, and the radius of curvature of the pressing head is proportional to the elastic modulus and yield strength of the sample material to be formed.

10. The U-shaped sample preparation device according to claim 1, characterized in that: The base is also provided with a scale ruler, which is located at one side of the embedding groove and extends in the same direction as the embedding groove.

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