CN217403976U - Tensile chuck device for metal pipe tensile test - Google Patents

Abstract

The utility model discloses a tensile chuck device for tensile test of metal pipes. The structure of the tensile chuck device comprises two symmetrical connecting sleeves, two quick-connecting pendants and two clamping combined units; the utility model is characterized in that : The tensile testing machine is connected to one end of the left connecting sleeve, the other end of the left connecting sleeve is connected to one end of the left quick connection pendant, and the other end of the left quick connecting pendant is connected to the left clamping combination unit; the tensile testing machine is connected to one end of the right connecting sleeve, and the right The other end of the coupling sleeve is connected to one end of the right quick connection pendant, the other end of the right quick connection pendant is connected to the right clamping combination unit, and the sample is placed between the left clamping combination unit and the right clamping combination unit. The advantages of the utility model are: simple structure, higher practicability, simple operation, rapid and accurate installation, which can not only ensure the accuracy of experimental data, but also improve the experimental efficiency; Good circulation.

Description

A tensile chuck device for tensile test of metal pipes

technical field

The utility model belongs to the technical field of tensile testing of metal materials, in particular to a tensile chuck device for tensile testing of metal pipes.

Background technique

Tensile testing refers to a test method for determining the properties of a material under an axial tensile load. Using the data obtained from the tensile test, the elastic limit, elongation, elastic modulus, proportional limit, area reduction, tensile strength, yield point, yield strength and other tensile properties of the material can be determined. Creep data can be obtained from tensile tests conducted at elevated temperatures. The procedure for tensile testing of metals can be found in the ASTM E-8 standard. Methods for tensile testing of plastics are found in ASTM D-638, D-2289 (high strain rate) and D-882 (sheet). ASTM D-2343 standard specifies the tensile test method applicable to glass fibers; ASTM D-897 standard specifies the tensile test method applicable to adhesives; ASTM D-412 standard specifies the tensile test for hard rubber method. A test to determine a series of properties of a material under a tensile load, also known as a tensile test. It is one of the basic methods for testing the mechanical properties of materials.

The tension clamp itself is a locking mechanism. There is no fixed pattern in the structure, and the structure varies greatly according to different samples and the size of the test force. The sample with large test force generally adopts the inclined surface clamping structure. With the increase of the test force, the clamping force increases. The shoulder sample adopts the suspension structure, etc. If the fixture is divided according to the structure, it can be divided into wedge-shaped fixture The clamp with the principle structure of bevel locking), the clamp type clamp (referring to the clamp with the principle structure of single-sided or double-sided thread clamping), the winding type clamp (referring to the clamp in which the sample is locked by winding method), the eccentric type clamp Adopt (clamp with eccentric locking principle structure), lever type clamp (refers to the clamp with lever force amplification principle structure), shoulder type clamp (refers to the clamp suitable for the shoulder sample), bolt type clamp (refers to the bolt type clamp , screws, studs and other fixtures for testing thread strength), 90° peeling fixtures (referring to the fixtures suitable for vertical and straight peeling of two samples), etc. We know that the mechanical locking structures include: threads (ie bolts, screws, nuts), bevels, eccentrics, levers, etc. The fixture is a combination of these structures. The structures of these fixtures have their own advantages and disadvantages, such as: wedge-shaped fixtures , the initial clamping force is small and increases with the test force. The clamping force increases accordingly. For the clamping fixture, the initial clamping force is large, and as the test force increases, the clamping force decreases.

Most of the tensile fixtures in the market are suitable for tensile specimens of metal bars or metal sheets. For tensile specimens of metal pipes, most of the fixtures for sheet specimens are used. Since most of the pipe tensile samples are arc-shaped section tests, this kind of sample is cut from the pipe, and the clamping end is an arc-shaped section. The direct use of the plate tension fixture may result in a small clamping area and a loose clamping. Or the problem of large deformation of the sample, the error is large, and accurate experimental results cannot be obtained. In order to ensure stable clamping, the clamping end of the sample can be flattened after the sample is cut, but this requires additional work, and the experiment is time-consuming and labor-intensive. Ordinary collets cannot meet the tensile test requirements of metal pipe tensile specimens.

Aiming at the many shortcomings of the existing fixtures for tensile test of metal pipe samples, a tensile chuck device for tensile test of metal pipe is proposed.

SUMMARY OF THE INVENTION

In order to solve the phenomenon that the tensile fixture cannot fit the clamping surface of the curved profile specimen in the tensile test of the metal pipe, resulting in small clamping force between the fixture and the specimen, slipping of the specimen, and wear of the jaws of the fixture, etc. Therefore, the problems such as test results and data accuracy are affected, and the utility model provides a tensile chuck device for tensile test of metal pipes.

In order to achieve the above purpose, the utility model adopts the following technical scheme: a tensile chuck device for tensile test of metal pipes, the structure of the tensile chuck device comprises two symmetrical connecting sleeves, two quick connection pendants and Two clamping combination units; it is characterized in that: the tensile testing machine is connected to one end of the left connection sleeve, the other end of the left connection sleeve is connected to one end of the left quick connection pendant, and the other end of the left quick connection pendant is connected to the left clamping combination unit; The testing machine is connected to one end of the right connection sleeve, the other end of the right connection sleeve is connected to one end of the right quick-connect pendant, the other end of the right quick-connect pendant is connected to the right clamping combination unit, and the test machine is placed between the left clamping combination unit and the right clamping combination unit. Sample.

Further, one end of the connecting sleeve is a semi-open T-shaped groove, and the other end is an internal thread; a connecting pendant is hung on the T-shaped groove, which can realize the quick hanging of the clamping unit, and the internal thread is connected to the upper pull rod of the tensile testing machine. External thread mating connection.

Further, one end of the quick connection pendant is a large boss, which fits with the semi-open T-shaped groove of the coupling sleeve with a large gap, and the other end is the connecting end, the two sides are straight, and the straight lower part has a light hole, and the light hole It is bolted to the clamping unit. Among them, the clearance fit is convenient for quick hanging, and the upper part of the straight side is fitted to the wall of the T-shaped groove to ensure that the sample is in the middle of the chuck, so as to ensure that the sample is not biased.

Further, the clamping combination unit is composed of an upper clamping end part with a concave arc curved surface and a lower clamping end part with a convex arc curved surface, and the upper clamping end part of the concave arc curved surface and the lower clamping end part of the convex arc curved surface. The holding parts each have two holes for fastening and connection, one of which is a light hole, and the other is a threaded hole, which is matched with the bolt; the concave curved surface of the upper holding end part of the concave arc curved surface Knurling, convex knurling of the lower clamping end part of the convex curved surface. The metal pipe tensile sample is clamped between the upper clamping end part of the concave arc curved surface and the lower clamping end part of the convex arc curved surface, so that the clamp is tightly fitted by the clamping end of the sample on both sides, and the force is uniform. It is not easy to cause stress concentration. The concave-convex surface knurling treatment increases the frictional resistance of the contact surface and solves the problem of slippage during the tensile process of the sample, so that the sample will not slip or deform greatly due to the force during the test.

Further, the bolts are standard bolts, and the bolt connection is matched with an opening gasket. The bolt realizes the fastening connection between the clamping combination and the metal pipe sample; and the clamping end is connected with the connecting quick connection pendant, and the opening gasket increases the friction force to prevent the fastener from withdrawing and loosening.

The utility model has the following beneficial effects: (1) The arc surface design adopted at the clamping end of the collet of the utility model realizes the close fit with the arc-shaped section tensile sample of the metal pipe, and the clamping force area is larger. Large, uniform force, the sample is not easy to slip and fall off and deform, and the test data is accurate and reliable; (2) the utility model has an ingenious structure, and is connected by bolts, which is convenient for disassembly and assembly. The connection with the clamping unit and the tensile testing machine adopts the fast hanging method, the side wall of the T-shaped groove is positioned, the hanging and taking are convenient and fast, and the positioning is accurate; (3) The utility model has the advantages of simple structure, higher practicability, simple operation and rapid installation. , accurate, not only can ensure the accuracy of the experimental data, but also can improve the experimental efficiency; (4) the utility model has low production cost, saves energy and raw materials, and has good liquidity in the market.

Description of drawings

Figure 1 is a schematic structural diagram of the utility model.

FIG. 2 is a front view of the utility model.

FIG. 3 is a first structural schematic diagram of the coupling sleeve of the present invention.

FIG. 4 is a second structural schematic diagram of the coupling sleeve of the present invention.

FIG. 5 is a schematic structural diagram of a quick connection pendant of the present invention.

6 is a schematic structural diagram of the upper clamping end component of the concave arc curved surface of the present invention.

7 is a schematic structural diagram of the lower clamping end component of the convex curved surface of the present invention.

In the figure, 1. Left coupling sleeve, 2. Left quick-connect pendant, 3. Left clamping combination unit, 4. Right coupling sleeve, 5. Right quick-connecting pendant, 6. Right clamping combination unit, 7. Sample, 8. Fastening bolt, 9. Opening gasket, 10. Upper clamping end part of concave arc curved surface, 11, Lower clamping end part 11 of convex arc curved surface.

Detailed ways

The preferred embodiments of the present invention will be described below with reference to FIG. 1 . It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, but not to limit the present invention.

The utility model works and is implemented in this way, a tensile chuck device for tensile test of metal pipes, its structure includes a left connecting sleeve 1, a left quick connecting pendant 2, a left clamping combination unit 3, a right connecting sleeve Cylinder 4, right quick connection pendant 5, right clamping combination unit 6, fastening bolt 8 and opening gasket 9; left connecting sleeve 1 and right connecting sleeve 4 One end of the connecting sleeve 1 and the right connecting sleeve 4 is an internal thread, which is matched with the external thread of the upper pull rod of the tensile testing machine, and the other end is opened with a T-shaped groove, and a clamping unit is hung on it. One end of the T-shaped groove is open, and a quick Connect the pendant to facilitate the quick attachment of the clamping unit. The clamping end combination clamps the metal tensile arc specimen in the middle, and clamps it by the tightening bolt 8. The clamping end is basically rectangular, but the jaw surface in contact with the test is arc-shaped. The two metal clamping ends are in close contact with the metal pipe sample, and the contact surface is knurled to increase the friction force of the contact surface. The clamping combination unit is composed of an upper clamping end member 10 having a concave arc-shaped curved surface and a lower clamping end member 11 having a convex arc-shaped curved surface.

Among them, if the tie rod of the testing machine is an internal thread, the internal thread of the connecting sleeve can be changed to an external thread. The basic shape of the quick connection pendant is a boss structure. The big end boss hangs in the T-shaped groove of the metal coupling cylinder. The small end of the connecting pendant is the connecting end, the two sides are straight, the straight lower part has light holes, and is connected with the clamping group by bolts and opening gaskets; Specimen 7 is in the middle of the chuck to ensure that the specimen is subjected to vertical force and the tensile force does not deviate.

The metal pipe tensile sample needs to be clamped in pairs, and the concave-convex arc-shaped curve is matched up and down, and the metal pipe tensile sample is sandwiched in the middle, so that the clamping ends of the sample are tightly attached, the force is uniform, and it is not easy to cause stress concentration. . The concave-convex surface knurling treatment increases the frictional resistance of the contact surface, so that the sample will not slip or deform greatly due to the force during the test. There are two holes on each clamping assembly for fastening and connection. In the combination, one clamping end hole is a light hole, and the other clamping end hole is a threaded hole, which is matched with the bolt. The clamp connection fasteners are bolts, and the holes on the arc surface of the clamping end are connected by bolts to realize the fast connection between the clamping combination and the metal pipe sample; the flat surface of the clamping end is connected with the quick connection pendant through bolts. The bolted connections are equipped with open spacers to increase friction and prevent fasteners from withdrawing and loosening.

The tensile chuck device of the metal pipe tensile test of the utility model has a specific installation method, and the steps are as follows:

Step 1: First, install the left connecting sleeve 1 and the right connecting sleeve 4 on the upper and lower tension rods of the metal tensile testing machine by connecting means (threaded connection).

Step 2: Pre-assemble the left quick connection pendant 2 and right quick connection pendant 5, the left clamping combination unit 3 and the right clamping combination unit 6, the fastening bolts 8, and the opening gasket 9, leaving some tightening allowances , not locked;

Step 3: Clip the metal pipe arc profile sample 7 between the left clamping combination unit 3 and the right clamping combination unit 6, align the hole position, install the opening gasket 9, and pre-tighten it with the fastening bolt 8;

Step 4: Tighten the four fastening bolts 8, and hang the clamping unit in the T-slots of the left connecting sleeve 1 and the right connecting sleeve 4, adjust the positions, and ensure that the sample is naturally vertically downward, and not forceful;

Step 5: Set the tensile test program, start the program, and start the tensile test;

Step 6: After the sample is broken, stop the test procedure and save the data;

Step 7: Adjust the position of the upper and lower tension rods, and quickly remove the chuck from the testing machine;

Step 8: Cool the sample if necessary, then loosen the bolt and remove the sample after the sample;

Step 9: Reinstall the tensile specimen and repeat the test.

The tensile clamp device of the utility model is suitable for clamping the metal pipe tensile test sample, and the fit and experimentability of the clamping surface of the metal pipe tensile sample are more matched, which ensures that the sample is stretched during the stretching process. There will be no bending, scratches, macro defects, cracks and other problems. The clamping head of the tensile testing machine has two arc-shaped clamping surfaces, and the surfaces of the two clamping surfaces of the clamping end in contact with the metal pipe sample are knurled to increase the surface friction coefficient, thereby increasing the metal pipe sample. Friction with the arc chuck. The jaw surface is arc-shaped, which can closely fit the tensile specimen of the metal pipe. The results show that the maximum stress, maximum strain and deformation of the specimen are mainly concentrated in the deformation area in the middle of the specimen when the tensile chuck of the utility model is used for the tensile test. experimental needs. The tensile chuck device effectively clamps the tensile specimen of the metal pipe, which effectively reduces the deformation of the clamping end caused by other clamping methods, resulting in the occurrence of experimental errors. At the same time, the collet fits the sample as much as possible, which increases the force-bearing area, makes the experimental data more accurate, prolongs the life of the collet, and reduces the experimental cost.

Claims (5)

1. A tensile chuck device for a metal pipe tensile test structurally comprises two symmetrical connecting sleeves, two quick connecting pendants and two clamping combination units; the method is characterized in that: the tensile testing machine is connected with one end of the left connecting sleeve, the other end of the left connecting sleeve is connected with one end of the left quick connecting hanging piece, and the other end of the left quick connecting hanging piece is connected with the left clamping combination unit; the tensile testing machine is connected with one end of the right connecting sleeve, the other end of the right connecting sleeve is connected with one end of the right quick connecting hanging piece, the other end of the right quick connecting hanging piece is connected with the right clamping combination unit, and a sample is placed between the left clamping combination unit and the right clamping combination unit.

2. The tensile collet device of claim 1, wherein: one end of the connecting sleeve is a half-opening T-shaped groove, and the other end of the connecting sleeve is an internal thread; a connecting hanging piece is hung on the T-shaped groove, and the internal thread is matched and connected with the external thread of the upper pull rod of the tensile testing machine.

3. The tensile collet device of claim 1, wherein: one end of the quick connection hanging piece is a large boss which is in large clearance fit with the half-opening T-shaped groove of the connection sleeve, the other end of the quick connection hanging piece is a connection end, two side faces are straight, the straight lower part is provided with a unthreaded hole, and the unthreaded hole is connected with the clamping combination unit through a bolt.

4. The tensile collet device of claim 1, wherein: the clamping combination unit is composed of an upper clamping end part with a concave arc-shaped curved surface and a lower clamping end part with a convex arc-shaped curved surface, the upper clamping end part with the concave arc-shaped curved surface and the lower clamping end part with the convex arc-shaped curved surface are respectively provided with two holes for fastening and connecting, one clamping end hole is a smooth hole, and the other clamping end hole is a threaded hole and is matched with a bolt; and knurling the concave curved surface of the upper clamping end part of the concave arc-shaped curved surface, and knurling the convex curved surface of the lower clamping end part of the convex arc-shaped curved surface.

5. The tensile collet device of claim 3, wherein: the bolt is a standard bolt, and the bolt is matched with an opening gasket.

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