Clamping device for high-temperature tensile sample for metal sheet and use method of clamping device

[0040] Example 1

[0041] As shown in the figure, a clamping device for a high-temperature tensile test specimen of a thin metal plate. Both ends of the test specimen 6 are provided with fixing parts, and each fixing part is provided with a pin hole. The clamping device passes A pin hole is used to clamp and fix the sample 6. The clamping device includes a clamp body 1 and a clamping portion 2 connected to the clamp body 1. One end of the clamp body 1 is provided with a threaded hole 101. The threaded hole A connecting rod is installed in 101. One end of the connecting rod away from the threaded hole 101 is connected to the tensile test equipment. The other end of the clamp body 1 is provided with a clamping portion 2 integrally provided with the clamp body. An end of the clamping portion 2 away from the threaded hole 101 is provided with a groove 201 with an isosceles trapezoid in cross section, and the groove 201 extends along the end of the clamping portion 2 to one side of the clamp body 1, and And the groove 201 penetrates the side wall of the clamping portion 2;

[0042] The present invention abandons the conventional clamping structure with a square or U-shaped opening, and designs a clamping part 2 with a trapezoidal opening in the front and rear direction. The groove 201 is arranged in the center of the end of the clamping part 2, and there are two grooves 201. The clamping parts 2 on the side are symmetrically distributed, matching the corresponding wedge-shaped washer I3 and the wedge-shaped washer II4, only need to align the wedge-shaped washer I3 and the wedge-shaped washer II4 respectively and insert the clamping part 2 and the ring-shaped washer I7 And the gap between the clamping part 2 and the annular gasket Ⅱ8, the sample 6 and the clamping part 2 can be tightly connected, and the coaxiality between the center of the sample and the force direction is good;

[0043] The groove 201 is sequentially provided with a wedge-shaped gasket I3, a ring-shaped gasket I7, a sample 6, a ring-shaped gasket II8, and a wedge-shaped gasket II4. The wedge angles of the wedge-shaped gasket I3 and the wedge-shaped gasket II4 are equal. The bottom angle of the isosceles trapezoid surrounded by the cross-section of the groove 201 is the same, the wedge-shaped gasket I3 and the wedge-shaped gasket II4 are symmetrically arranged on both sides of the sample 6, and the inner surface of the groove 2 is The wedge-shaped surface of the wedge-shaped gasket Ⅰ3 and the wedge-shaped gasket Ⅱ4 maintain a certain degree of roughness. After the wedge-shaped gasket Ⅰ and the wedge-shaped gasket Ⅱ are gently inserted into the clamping part, the wedge-shaped gasket can be guaranteed by the friction caused by the surface roughness. The relative position between the sheet and the clamping part will not cause problems such as slippage of the wedge gasket Ⅰ3 and wedge gasket Ⅱ4 when the clamping device is moved and the clamping device is connected to the tensile test equipment;

[0044] The top end of the wedge-shaped washer I3 is provided with a guide groove I303 extending downward and the longitudinal section is U-shaped, the bottom end of the wedge-shaped washer I3 is provided with a fixing block I301, and the guide groove I303 is along the line of the wedge-shaped washer I3. The end portion extends to one side of the fixed block I301, and the guide groove I303 penetrates the side wall of the wedge-shaped gasket I3, and the fixed block I301 is provided with a positioning hole I302;

[0045] The top end of the wedge-shaped washer II4 is provided with a guide groove II403 extending downward and the longitudinal section is U-shaped, the bottom end of the wedge-shaped washer II4 is provided with a fixing block II401, and the guide groove II403 is along the wedge-shaped washer The end of II4 extends to one side of the fixed block II401, and the guide groove II403 penetrates the side wall of the wedge-shaped gasket II4. The fixed block II401 is provided with a positioning hole II402. The fixed block I301 and the The fixing block II401 has a semicircular structure, the positioning hole I302 is set at the center of the fixing block I301, the positioning hole II402 is set at the center of the fixing block II401, and the positioning hole I302 and the The positioning pin 5 is installed in the positioning hole II 402; the opening size of the guide groove I 303 and the guide groove II 403 are slightly larger than the diameter of the fixed pin 9, the inner diameter of the ring gasket I 7 and the ring gasket II 8 is the same as the size of the pin hole of the fixed end of the sample 6. Consistent, the ring gasket can tightly restrain the lateral deformation near the pin hole of the sample, and fundamentally eliminate the test failure caused by the deformation near the pin hole of the sample, the tension in the middle of the pin hole or the fracture of the edge of the sample head Or the problem of reduced accuracy of test results;

[0046] The wedge-shaped washer I3 is inserted into the gap between the annular gasket I7 and the side wall of the groove 201 through the guide groove I303 provided at the top end, and the wedge-shaped washer II4 is inserted through the guide groove I303 provided at the top end. The guide groove II 403 is inserted in the gap between the annular gasket II 8 and the side wall of the groove 201, the wedge gasket I3 and the wedge gasket II 4 are symmetrically arranged with respect to the sample, the wedge gasket I3 and the wedge gasket The wedge-shaped surface of the sheet II 4 is attached to the two side walls of the groove 201 respectively, and the width of the guide groove I 303 and the guide groove II 403 is not less than the diameter of the fixing pin 9;

[0047] Wedge gaskets Ⅰ3, wedge gaskets Ⅱ4, annular gaskets Ⅰ7 and annular gaskets Ⅱ8 are all made of materials with larger thermal expansion coefficients. These materials can be high-nickel alloys, austenitic stainless steels and copper alloys with larger thermal expansion coefficients. Any of them; during the heating and heat preservation of the sample, the thickness of the above four gaskets increases due to expansion. The force generated by laterally squeezing the sample restrains the deformation near the pin hole of the sample to prevent the test Deformation, tearing, or breakage of the head edge near the sample pin hole, etc., at the same time, it can bridge the tiny gap left during the assembly process of the sample and the clamping part, and complete the solid connection between the sample and the clamping part;

[0048] The clamping portion 2 is provided with a through hole I 202 and a through hole II 203. The through hole I 202 and the through hole II 203 are symmetrically arranged on both sides of the groove 201 and their central axes coincide. The through hole I 202 A fixing pin 9 is installed in the through hole II 203, and the fixing pin 9 passes through the through hole I 202, the ring gasket I 7, the sample 6, the ring gasket II 8 and the through hole II 203, and then the sample 6 is fixed in the The clamping part 2 on.

[0049] A method of using a clamping device for a high-temperature tensile test specimen of a metal sheet includes the following steps:

[0050] a. Connect the clamp body 1 and the connecting rod through a threaded manner;

[0051] b. Place the clamp body 1 flat on the operating table, put the ring gasket I7, the fixing part of one end of the sample 6, and the ring gasket II8 into the groove 201, and the fixing pins 9 from left to right in turn After passing through the through hole I202, the ring gasket I7, the pin hole corresponding to the fixing part, the ring gasket II8 and the through hole II203, the sample 6 is fixed on the clamping part 2;

[0052] c. Install the positioning pin 5 in the positioning hole I302 and the positioning hole II402, and then set the end of the wedge washer I3 with the guide groove I303 and the end of the wedge washer II4 with the guide groove II403 as the first wedge end, Respectively align the gaps between the clamping portion 2 and the ring gasket I7 and the clamping portion 2 and the ring gasket II8, and at the same time, align the guide groove I303 and the guide groove II403 with the fixing pin 9, and then apply uniform force In the process of pressing the wedge gasket I3 and the wedge gasket II4, the guide groove I303 and the guide groove II403 respectively pass through the fixing pin 9, and as the wedge gasket I3 and the wedge gasket II4 are pressed uniformly, the test of the sample 6 is realized. Centering and fixing;

[0053] d. Repeat step c to fix the other fixed end of the sample 6;

[0054] e. Connect the sample 6 together with the fixture body 1 to the tensile test equipment, put it in a high-temperature furnace for heating and heat preservation, and then complete the stretching process;

[0055] f. After the stretching is finished, remove the sample 6 and the fixture body 1 from the tensile test equipment, place them on the operating table, and let them cool to room temperature, tap the wedge gasket Ⅰ3 and the wedge gasket Ⅱ4 to first Remove the wedge-shaped washer Ⅰ3 and wedge-shaped washer Ⅱ4, and then pull out the fixing pin 9 to complete the disassembly of the clamping device. The test is over.

[0056] The device of the present invention has a compact structure, a simple method of use, and good centering and fixing effects; the clamping method of the present invention can realize high-temperature stretching of metal sheets of series specifications and sizes through a set of tooling, wedge gasket Ⅰ3 and wedge gasket Ⅱ4 The sample is clamped and has strong versatility. After verification, the invention can be used for high temperature tensile test of metal sheet ≥0.3mm;

[0057] The tightening force of the clamping device of the present invention comes from the lateral force generated when wedge-shaped washer Ⅰ3 and wedge-shaped washer Ⅱ2 are The generated lateral force has a large force value and has a good binding effect on the clamping end of the specimen.

[0058] Example 2

[0059] According to the clamping device and its method of use in Example 1, the material of the metal sheet is selected as Ti70, the thickness of the metal sheet is δ=1.5mm, the test temperature of the high-temperature furnace is 600 ℃, and the high-temperature tensile test is performed. Stress-strain curve see Figure 7.

[0060] Example 3

[0061] According to the clamping device and its method of use in Example 1, the material of the thin metal plate is Ti31, the thickness of the thin metal plate is δ=0.7mm, the test temperature of the high-temperature furnace is 350℃, and the high-temperature tensile test is performed. Stress-strain curve see Figure 8.

[0062] From Example 2 and Example 3, it can be seen that the clamping device and the method of use of the present invention are used for high temperature tensile test, and the wedge gasket Ⅰ3 and wedge gasket Ⅱ4 can be used to complete the high temperature of metal sheets with multiple specifications. After the tensile test, there was no obvious deformation at the fixed end of the sample, and the elastic section of the obtained stress-strain curve was linear, indicating that the clamping device and the method of use of the invention have good versatility and usability , Can be promoted.