A sample fixture for pipe or bar for tensile test

Abstract

The invention discloses a specimen holder of a tube or a bar for a tension test. The specimen holder comprises a tension handle, a locking part, a holding seat and a holder body, wherein the holder body comprises a cylinder body and a circular truncated cone body which are integrally formed; the maximum external diameter of the circular truncated cone body is greater than the external diameter of the cylinder body; the whole circular truncated cone body is provided with at least two grooves along the axial direction, and the two grooves are used for segmenting the circular truncated cone body into holding blocks; a holding part for holding a test specimen is arranged on the inner surface of each clamping block; the holding seat sleeves the outside of the holder body and is connected with the holder body in a matching way; the holding seat is provided with a first conical surface matched with the circular truncated cone body; the front end of the locking part is connected with the holding seat through a spiral structure; the tension handle is connected with the rear end of the locking part. The specimen holder disclosed by the invention is small in size, convenient in disassembly and assembly and uniform and reliable in holding force; the specimen holder realizes automatic centering in a clamping process, is uniform, quick and reliable in clamping, and is particularly suitable for being used in a high-low temperature environmental cabinet with compact structure and small space.

Description

technical field [0001] The invention relates to a pipe or bar performance test fixture, specifically a fixture for clamping a pipe or bar when testing the tensile properties of a circular pipe or bar, and accordingly provides a The test equipment is small in size, easy to disassemble and assemble, and the clamping force is uniform and reliable. It is automatically centered during the clamping process, and the clamping is uniform, fast and reliable. It is especially suitable for use in high and low temperature environmental chambers with compact structures and small spaces. Some new materials have comprehensively tested their mechanical properties at service temperature. Background technique [0002] When conducting tensile performance tests, some materials, especially some new materials, must fully measure their mechanical properties at service temperature, mainly relying on the high and low temperature environmental chamber configured by the material testing machine. [00...

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Problems solved by technology

[0006] But for pipes, especially thin-walled pipes, the above two methods are not feasible, the size of the chuck of the testing machine is too large, and the environmental chamber cannot accommodate it at all, and thin-walled pipes still have clamping problems, such as excessive clamping force It is easy to cause damage to the pipe wall, resulting in the failure of the test or the large deviation between the data obtained from the test and the actual situation of the pipe itself

[0007] In addition, the pipe or bar sample fixtures used in the existing tensile testing machines are generally large in size, or small in size but insufficient in testing force. Assembly and disassembly of special tools; on the one hand, the centering degree of the fixture is poor, the clamping force is uneven, and the sample often breaks in an abnormal position during the stretching process; on the other hand, due to the lack of better accurate centering and clamping devices , the fixture is often prone to "cracking teeth" and "locking", which makes the fixture scrapped or cannot be disassembled and reused. The sample can no longer be tested; also due to the existence of the above reasons, the data of the sample test has errors and unsatisfactory

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