Clamping mechanism and sample compression method for hot simulation testing apparatus

Abstract

The application discloses a clamping mechanism for a hot simulation test device and a sample compression method, relates to the technical field of metal material thermal deformation, and discloses a clamping mechanism for a hot simulation test device, which is used for clamping a sample, and the hot simulation test device comprises a driving piece and two clamping grooves. According to the technical scheme, the clamping mechanism is used for clamping the sample, the hot simulation test device comprises the driving piece and the two clamping grooves, clamping components are arranged on both sides of the thickness direction of the sample, and the plane of the sample is contacted with the conductive element, so that the plane strain state of the sample in the hot compression test simulation plate rolling process is realized, stress concentration and bending effect caused by uneven contact of the traditional knurled side are avoided, the simulation of the plane strain state is more accurate and reliable, and the accuracy and repeatability of test data are improved; the driving piece is used for controlling the movement of the clamping grooves, the clamping components can be flexibly adjusted in position, and stress distribution of the sample in the hot simulation test is closer to the actual rolling state.

Description

Technical Field

[0001] This invention relates to the field of thermal deformation technology of metallic materials, and in particular to a clamping mechanism and a sample compression method for a thermal simulation testing device. Background Technology

[0002] For materials and thermal processing, physical simulation typically uses small-sized specimens and thermal simulation devices to reproduce the physical processes of heating and cooling during the preparation or thermal processing of materials.

[0003] Researchers commonly use cylindrical specimens with uniaxial compression to obtain the high-temperature rolling deformation resistance of metallic materials. However, the simulated state of uniaxial compression tests differs significantly from the actual rolling process, exhibiting the following characteristics: First, in addition to end-conductive heat dissipation, uniaxial compression of cylindrical specimens involves radiative heat dissipation from the sides, which contradicts the conductive heat dissipation of actual rolled plates, which only involves contact with the rolls. Second, uniaxial compression specimens experience one-dimensional stress but generate three-dimensional strain in both the axial and radial directions, while rolled plates experience three-dimensional stress and generate approximately two-dimensional strain with small width expansion and significant changes in length and thickness. Third, due to end-friction, uniaxial compression specimens exhibit significant bulging, resulting in uneven distribution of actual compression strain. A large strain gradient exists from the specimen end to the center, making it impossible to accurately simulate the actual deformation distribution during plate rolling. Furthermore, due to the different stress dimensions, the deformation resistance obtained from uniaxial compression is generally less than that obtained from actual plane strain compression. Summary of the Invention

[0004] The main objective of this invention is to provide a clamping mechanism and a sample compression method for a thermal simulation testing device, which aims to achieve the same deformation state as hot rolling of sheet metal in the field during thermal compression testing.

[0005] To achieve the above objectives, the present invention proposes a clamping mechanism for a thermal simulation testing apparatus. The clamping mechanism is used to clamp a specimen. The thermal simulation testing apparatus includes a driving member and two clamping slots. The clamping mechanism for the thermal simulation testing apparatus includes two clamping assemblies, which are respectively disposed on both sides of the specimen's thickness direction and located within the clamping slots. Each clamping assembly includes a clamping element and a conductive element. The clamping element has a receiving space, and the conductive element is installed within the receiving space, protruding from the receiving space on the side closer to the specimen. The driving member can drive one of the clamping slots to move closer to the specimen, so that the conductive elements of the two clamping assemblies compress the specimen. The specimen has two planes arranged along its thickness direction, and the conductive element contacts the planes.

[0006] In one embodiment, the clamping member includes two clamping blocks, each of which has a receiving cavity, and the receiving cavities of the two clamping blocks are joined together to form the receiving space.

[0007] In one embodiment, the conductive element is cylindrical, and the accommodating space has an arc surface that matches the outer surface of the conductive element, with the conductive element conforming to the arc surface.

[0008] In one embodiment, the cross-sectional shape of the accommodating cavity is set to a fan shape.

[0009] In one embodiment, the clamping block has a reserved groove on the side near the sample, and the reserved groove is connected to the corresponding receiving cavity.

[0010] In one embodiment, the sample includes a sample body and two temperature sensors disposed on the sample body, wherein the solder joints of the two temperature sensors are arranged along the length of the sample.

[0011] In one embodiment, the center of the line connecting the solder joints of the two temperature sensors is on the same horizontal line as the center of the end face of the conductive element, and the wide side of the sample body is parallel to the central axis of the conductive element.

[0012] In one embodiment, the diameter of the conductive element is greater than the length of the sample body, and the length of the conductive element is greater than the width of the sample body.

[0013] In one embodiment, an anti-sticking layer is provided on both sides along the thickness direction of the sample body.

[0014] The present invention also proposes a sample compression method for thermal simulation testing, including the clamping mechanism described above for the thermal simulation testing apparatus, the sample compression method comprising the following steps: The sample is contacted and compressed from both sides of the sample in the thickness direction by the conductive elements of the two clamping assemblies. Using the aforementioned thermal simulation testing device, a conductive path is formed between the conductive element and the sample to thermally compress the sample in the thickness direction, thereby simulating a plane strain state.

[0015] The technical solution of this invention achieves the simulation of the plane strain state during the rolling process of the sample by setting clamping components on both sides of the sample in the thickness direction and using conductive elements to contact the sample plane. This avoids the stress concentration and bending effect caused by uneven contact on the traditional knurled side, making the simulation of the plane strain state more accurate and reliable, and improving the accuracy and repeatability of the test data. By controlling the movement of the clamping groove through the driving component, the clamping components can be flexibly adjusted to ensure that the stress distribution of the sample in the thermal simulation test is closer to the actual rolling state. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the clamping mechanism (anti-adhesive layer not shown) provided by the present invention; Figure 2 This is a three-dimensional schematic diagram of the clamping block in the clamping mechanism provided by the present invention.

[0018] Explanation of icon numbers: 100. Clamping mechanism; 1. Clamping assembly; 11. Clamping component; 111. Receiving space; 112. Clamping block; 1121. Receiving cavity; 12. Conductive element; 3. Arc surface; 4. Reserved groove; 5. Sample; 51. Sample body; 52. Temperature sensor.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0022] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0023] For materials and thermal processing, physical simulation typically uses small-sized specimens and thermal simulation devices to reproduce the physical processes of heating and cooling during the preparation or thermal processing of materials.

[0024] Researchers commonly use cylindrical specimens with uniaxial compression to obtain the high-temperature rolling deformation resistance of metallic materials. However, the simulated state of uniaxial compression tests differs significantly from the actual rolling process, exhibiting the following characteristics: First, in addition to end-conductive heat dissipation, uniaxial compression of cylindrical specimens involves radiative heat dissipation from the sides, which contradicts the conductive heat dissipation of actual rolled plates, which only involves contact with the rolls. Second, uniaxial compression specimens experience one-dimensional stress but generate three-dimensional strain in both the axial and radial directions, while rolled plates experience three-dimensional stress and generate approximately two-dimensional strain with small width expansion and significant changes in length and thickness. Third, due to end-friction, uniaxial compression specimens exhibit significant bulging, resulting in uneven distribution of actual compression strain. A large strain gradient exists from the specimen end to the center, making it impossible to accurately simulate the actual deformation distribution during plate rolling. Furthermore, due to the different stress dimensions, the deformation resistance obtained from uniaxial compression is generally less than that obtained from actual plane strain compression.

[0025] This invention proposes a clamping mechanism and a sample compression method for a thermal simulation test device, aiming to achieve the goal of bringing the thermal compression test to the same deformation state as the hot rolling of the plate in the field.

[0026] Please see Figure 1 and Figure 2 In one embodiment of the present invention, the clamping mechanism 100 for a thermal simulation testing device is used to clamp a sample 5. The thermal simulation testing device includes a driving member and two clamping slots. The clamping mechanism 100 for the thermal simulation testing device includes two clamping assemblies 1, which are respectively disposed on both sides of the sample 5 in the thickness direction. The clamping assemblies 1 are located within the clamping slots. Each clamping assembly 1 includes a clamping member 11 and a conductive element 12. The clamping member 11 has a receiving space 111, and the conductive element 12 is installed within the receiving space 111, protruding from the receiving space 111 on the side closer to the sample 5. The driving member can drive one of the clamping slots to move closer to the sample 5, so that the conductive elements 12 of the two clamping assemblies 1 compress the sample 5. The sample 5 has two planes arranged along its thickness direction, and the conductive element 12 contacts the planes.

[0027] The technical solution of the present invention achieves the simulation of the plane strain state of the plate rolling process by setting clamping components 1 on both sides of the thickness direction of the sample 5 and using conductive elements 12 to contact the plane of the sample 5. This avoids the stress concentration and bending effect caused by uneven contact on the traditional knurled side, making the simulation of the plane strain state more accurate and reliable, and improving the accuracy and repeatability of the test data. By controlling the movement of the clamping groove through the driving component, the clamping components 1 can be flexibly adjusted to ensure that the stress distribution of the sample 5 in the thermal simulation test is closer to the actual rolling state.

[0028] In some embodiments, the clamping member 11 can be configured as a single clamping block 112 integrated with the conductive element 12, resulting in a compact structure and high rigidity; or multiple clamping blocks 112 can be configured separately from the conductive element 12, with multiple clamping blocks 112 spliced ​​together to form a housing space 111 for installing the conductive element 12, which is highly reliable and easy to maintain.

[0029] Specifically, in one embodiment, the clamping member 11 includes two clamping blocks 112, each of which has a receiving cavity 1121. The receiving cavities 1121 of the two clamping blocks 112 are joined together to form the receiving space 111. Thus, by setting the clamping member 11 in the form of two clamping blocks 112, not only is the installation and maintenance of the conductive element 12 facilitated, but the size of the receiving space 111 can also be flexibly adjusted according to the specific dimensions of the sample 5. The joining structure of the two clamping blocks 112 ensures the integrity and stability of the receiving space 111, and also allows the conductive element 12 to maintain a precise positional relationship during the test. Furthermore, this split design effectively reduces contact problems caused by processing errors or assembly deviations, thereby further improving the reliability of the test and the accuracy of the data.

[0030] In some embodiments, the connection between the clamping member 11 and the conductive element 12 can be achieved by mechanical fixing, where a removable cover plate is provided on the clamping member 11, and the conductive element 12 is pressed into the receiving space 111 by tightening screws, which is convenient for disassembly and assembly; alternatively, a tenon and mortise method can be used, where an installation space adapted to the conductive element 12 is provided on the clamping member 11 for fitting and pressing, which is simple in structure; or adhesive or sintering methods can be used, where the conductive element 12 is bonded into the receiving space 111 with high-temperature conductive adhesive, or the conductive material and the clamping member 11 material are sintered into a whole by powder metallurgy, which has high reliability.

[0031] It should be explained that the clamping component 1 can be fixed in the clamping groove by using a groove with the same shape as the clamping component 1 and the clamping groove, and using an interference fit to directly snap the clamping component 1 into the groove for fixation. However, considering the issue of easy removal, the size of the groove is larger than the size of the clamping component 1. The remaining gap space is used to fasten the clamping component 1 to the groove to ensure the stability of the installation.

[0032] Specifically, in this embodiment, the clamping component 1 and the clamping groove are installed as follows: the clamping groove is set as a wedge-shaped groove, the clamping component 1 is set as a wedge (that is, two clamping blocks 112 are spliced ​​together to form a wedge), the clamping component 1 is inserted into the wedge-shaped groove, and then the clamping component 1 is pressed tightly in the wedge-shaped groove by means of fasteners (bolts and clamping plates) to ensure stability during test use.

[0033] The driving component can be a hydraulic cylinder, which moves by pushing the clamping groove to clamp the sample 5, and the continuous movement of the driving component can compress the sample 5.

[0034] In one embodiment, the conductive element 12 is cylindrical, and the accommodating space 111 has an arc surface 3 that matches the outer surface of the conductive element 12, with the conductive element 12 conforming to the arc surface 3. Thus, by using a cylindrical side to compress the specimen 5, surface shear strain can be introduced, creating a transition stage from surface shear compression strain to core compression strain in the specimen 5. This fully simulates the shear compression state during the rolling process of a metal sheet, allowing for a more realistic simulation of the specimen 5's state during on-site production. Simultaneously, the way the conductive element 12 conforms to the arc surface 3 improves the conductive path.

[0035] Preferably, in this embodiment, the conductive element 12 adopts a tungsten carbide cylindrical anvil arrangement, which has high compressive strength and high temperature resistance.

[0036] In this embodiment, if it is necessary to ensure the temperature uniformity of sample 5 during the test, the fixture is made of stainless steel; if it is necessary to rapidly cool sample 5 during the test, the fixture is made of copper.

[0037] In this embodiment, to better reflect the actual rolling process of sheet metal, sample 5 is set as a rectangular metal block sample 5.

[0038] To improve the success rate of the test, in one embodiment, the cross-sectional shape of the accommodating cavity 1121 is set to a fan shape. In this way, the cylindrical conductive element 12 can be wrapped inside the clamping member 11, ensuring that the conductive element 12 will not fall off during the movement of the clamping assembly 1, thereby improving the success rate of the test.

[0039] Preferably, in this embodiment, the sector angle is set to be no less than 200 degrees. In this way, while ensuring that the conductive element 12 is installed securely, its cylindrical side surface can also contact the sample 5 to form a conductive path.

[0040] Considering that in the hot compression test, after the middle section of the specimen 5 is compressed, the two uncompressed ends along its thickness direction are prone to deformation and expansion under pressure, and may easily come into contact with the clamping member 11, in order to reduce damage to the clamping member 11, in one embodiment, the clamping block 112 has a reserved groove 4 on the side near the specimen 5, and the reserved groove 4 is connected to the corresponding receiving cavity 1121. In this way, when the specimen 5 bulges and expands, the reserved groove 4 can provide a certain space to accommodate the deformed part, reducing its direct impact on the clamping member 11, thereby protecting the structural integrity of the clamping member 11. In addition, the design of the reserved groove 4 can also disperse the stress concentration generated during the deformation of the specimen 5 to a certain extent, reducing the risk of cracks or damage to the specimen 5 due to uneven stress.

[0041] In one embodiment, the sample 5 includes a sample 5 body and two temperature sensors 52 disposed on the sample 5 body, with the solder joints of the two temperature sensors 52 arranged along the length of the sample 5. Thus, the two temperature sensors 52 are used to accurately monitor the temperature of the sample 5, thereby enabling accurate temperature control of the sample 5 during the experiment; that is, by observing the readings of the two temperature sensors 52, the temperature distribution of the sample 5 along its length can be intuitively understood; if the two readings are very close, it indicates that the heating system is working well and the temperature of the sample 5 is uniform; if there is a continuous and large deviation, it suggests that there may be a problem with the equipment.

[0042] In this embodiment, the temperature sensor 52 is set up using a thermocouple, specifically a type K thermocouple (type K thermocouples are used when the peak test temperature is below 1250°C), and is installed on the sample 5 body by welding.

[0043] To ensure the overall temperature uniformity of the sample 5, in one embodiment, the center of the line connecting the solder joints of the two temperature sensors 52 is aligned with the center of the end face of the conductive element 12, and the wide side of the sample 5 body is parallel to the central axis of the conductive element 12. This allows the temperature sensors 52 to more accurately reflect temperature changes in key areas of the sample 5, thereby improving the overall reliability of temperature control. Simultaneously, it effectively reduces localized overheating or temperature differences caused by uneven contact between the conductive element 12 and the sample 5, further ensuring the accuracy of the test data.

[0044] It should be explained that the center of the end face of the conductive element 12 refers to the geometric center of the applied pressure load; the wide side of the specimen 5 body refers to the side of the specimen 5 that contacts the conductive element 12.

[0045] To enable the clamp to work with the conductive element 12, the diameter of the conductive element 12 needs to be greater than the length of the sample 5. In one embodiment, the diameter of the conductive element 12 is greater than the length of the sample 5 body, and the length of the conductive element 12 is greater than the width of the sample 5 body. This ensures complete coverage and uniform contact of the pressure and heat transfer interface, eliminates edge effects, and achieves uniform heat transfer and uniform pressure.

[0046] Preferably, the diameter of the conductive element 12 / the length of the sample 5 is 1.2 to 1.5; the length of the conductive element 12 / the width of the sample 5 is 1.5 to 2.

[0047] In one embodiment, an anti-stick layer is provided on both sides along the thickness direction of the sample 5 body. This reduces the likelihood of the sample sticking to the conductive element 12 during compression.

[0048] In this embodiment, the anti-adhesion layer is made of tantalum sheet and is connected to the sample 5 body by adhesive bonding.

[0049] The present invention also proposes a method for compressing a sample 5 for a thermal simulation test. The method for compressing a sample 5 for a thermal simulation test includes a clamping mechanism 100 for a thermal simulation test apparatus. The specific structure of the clamping mechanism 100 for the thermal simulation test apparatus is as described in the above embodiments. Since the present method for compressing a sample 5 for a thermal simulation test adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0050] In one embodiment, the compression method for the specimen 5 used in the thermal simulation test includes the following steps: The sample 5 is contacted and compressed from both sides of the sample 5 in the thickness direction by the conductive elements 12 of the two clamping assemblies 1. Using the thermal simulation test device, a conductive path is formed between the conductive element 12 and the sample 5 to thermally compress the sample 5 in the thickness direction to simulate the plane strain state.

[0051] In this embodiment, the plane strain state during the rolling process of sheet metal is simulated by hot compression test of block metal. The width direction of metal sample 5 only expands slightly, and the deformation of sample 5 is mainly characterized by length extension and thickness reduction. Based on precise temperature control, the compressive strain of sample 5 is uniformly distributed in the thickness direction.

[0052] Among them, sample 5 was obtained from one-quarter of the thickness of the continuous casting billet raw material, and the length, width and thickness of sample 5 were 30mm, 20mm and 10mm respectively; the diameter of conductive element 12 was 20mm and the length was 30mm.

[0053] Furthermore, when the conductive element 12 contacts the sample 5, it is necessary to ensure that the sample 5 is installed accurately, that is, the sample 5 is clamped between the conductive elements 12. At this time, the long and wide surfaces of the sample 5 are in contact with the side of the conductive element 12 exposed outside the clamping block 112. The center of the line connecting the two solder points of the thermocouple is on the same horizontal line as the center of the end face of the conductive element 12. The wide side of the sample 5 is parallel to the central axis of the conductive element 12.

[0054] In addition, during hot compression, a hot compression program was written in the data analysis software of the dynamic thermal simulation test device. The sample 5 underwent heating, heat preservation, and compression processes. During the compression process, the surface of the sample 5 was subjected to compression and shear strain at the same time, which fully conformed to the rolling deformation state of the plate.

[0055] Finally, stress-strain data were obtained from the experiment.

[0056] In one embodiment, the conductive element 12 itself is used as a resistive element. A large current is passed through it to generate Joule heat, which is used to heat the sample 5 to the target temperature via resistance heating. The sample 5 is then subjected to plane strain hot compression simulating the rolling process of sheet metal production. The introduction of resistance heating enables rapid and uniform temperature control of the metal sample 5, thereby ensuring temperature stability during the hot compression process.

[0057] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A clamping mechanism for a thermal simulation testing apparatus, the clamping mechanism being used to clamp a specimen, the thermal simulation testing apparatus comprising a driving member and two clamping slots, characterized in that, The clamping mechanism of the thermal simulation testing apparatus includes two clamping assemblies, which are respectively disposed on both sides of the sample in the thickness direction and are located in the clamping groove. Each clamping assembly includes a clamping member and a conductive element. The clamping member has a receiving space, and the conductive element is installed in the receiving space and protrudes from the receiving space on the side closer to the sample. The driving member can drive one of the clamping grooves to move closer to the sample, so that the conductive elements of the two clamping assemblies compress the sample. The sample has two planes arranged along its thickness direction, and the conductive element contacts the planes.

2. The clamping mechanism for a thermal simulation test apparatus as described in claim 1, characterized in that, The clamping member includes two clamping blocks, each of which has a receiving cavity, and the receiving cavities of the two clamping blocks are joined together to form the receiving space.

3. The clamping mechanism for a thermal simulation test apparatus as described in claim 2, characterized in that, The conductive element is cylindrical, and the accommodating space has an arc surface that matches the outer surface of the conductive element, with the conductive element fitting against the arc surface.

4. The clamping mechanism for a thermal simulation test apparatus as described in claim 2, characterized in that, The cross-sectional shape of the cavity is set to a fan shape.

5. The clamping mechanism for a thermal simulation test apparatus as described in claim 2, characterized in that, The clamping block has a reserved groove on the side near the sample, and the reserved groove is connected to the corresponding receiving cavity.

6. The clamping mechanism for a thermal simulation test apparatus as described in claim 1, characterized in that, The sample includes a sample body and two temperature sensors disposed on the sample body, with the solder joints of the two temperature sensors arranged along the length of the sample.

7. The clamping mechanism for a thermal simulation test apparatus as described in claim 6, characterized in that, The center of the line connecting the solder joints of the two temperature sensors is on the same horizontal line as the center of the end face of the conductive element, and the wide side of the sample body is parallel to the central axis of the conductive element.

8. The clamping mechanism for a thermal simulation test apparatus as described in claim 6, characterized in that, The diameter of the conductive element is greater than the length of the sample body, and the length of the conductive element is greater than the width of the sample body.

9. The clamping mechanism for a thermal simulation test apparatus as described in claim 6, characterized in that, An anti-sticking layer is provided on both sides along the thickness direction of the sample body.

10. A sample compression method for thermal simulation testing, characterized in that, Including the clamping mechanism for a thermal simulation testing apparatus as described in any one of claims 1-9, the sample compression method includes the following steps: The sample is contacted and compressed from both sides of the sample in the thickness direction by the conductive elements of the two clamping assemblies. Using the aforementioned thermal simulation testing device, a conductive path is formed between the conductive element and the sample to thermally compress the sample in the thickness direction, thereby simulating a plane strain state.

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