Wedge load test device for full-thread stud

Abstract

The utility model discloses a wedge load test device for a full-thread stud. A thread cavity is formed in an upper clamp and used for screwing threads at the upper end of the full-thread stud; a lower cavity is formed in the clamp body, an opening of the lower cavity is a first inclined face, the outer wall of the supporting pad is a second inclined face matched with the first inclined face, the supporting pad is arranged at the opening of the lower cavity and penetrates through the lower end of the full-thread stud, the lower end of the full-thread stud is located in the lower cavity and penetrates through a threaded hole of the threaded wedge pad, and the threaded wedge pad has an inclined angle. The method has the advantages that if the thread strength is insufficient, the defect on the surface of the thread can be torn to form a crack source under a multi-time wedge load test method, appearance inspection is performed on the thread of the full-thread stud after the test is finished, and if the crack source exists at the root of the thread, the thread strength of the full-thread stud is insufficient.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of testing technology, in particular to a wedge load test device for testing the reliability of a full thread stud under repeated load. BACKGROUND

[0002] The full thread stud is mainly used for flange connection on oil, chemical industry and pressure pipeline, and is subjected to hydraulic pulsating force, which belongs to high cycle stress. The bolt execution standard is GB / T22513 and HG20634, and the tensile test of the mechanical performance tensile test bar is adopted in the standard. The detection performance of the tensile test bar cannot completely replace the overall performance of the bolt, because the thread of the full thread stud is usually hot rolled after heat treatment. After hot rolling, the thread surface will have a 'hardening' phenomenon due to the influence of extrusion stress. When the thread is subjected to hydraulic high cycle pulsating force load, a crack source is easily formed at the hardened thread, which reduces the fatigue strength and causes early failure and fracture of the full thread stud. SUMMARY

[0003] The purpose of the present application is to solve the problems existing in the prior art, and a wedge load test device for testing the reliability of a full thread stud under repeated load is provided.

[0004] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0005] A wedge load test device for a full thread stud, comprising an upper clamp and a lower clamp, the lower clamp comprising a clamp body, a threaded wedge pad and a support pad, a threaded cavity is provided in the upper clamp for screwing the thread of the upper end of the full thread stud; a lower cavity is provided in the clamp body, the opening of the lower cavity is a first inclined surface, the outer wall of the support pad is a second inclined surface matched with the first inclined surface, the support pad is arranged at the opening of the lower cavity and passes through the lower end of the full thread stud, the lower end of the full thread stud passes through the threaded hole of the threaded wedge pad in the lower cavity, and the threaded wedge pad has an inclined angle.

[0006] Further, the lower end of the full thread stud passes through the inner hole of the support pad, and the diameter of the inner hole of the support pad is greater than the diameter of the full thread stud.

[0007] The beneficial effects of the present application are: 1. The carrying capacity of the full thread stud under bending force can be quickly evaluated;

[0008] 2. If the thread strength is insufficient, the defects on the thread surface will tear and form a crack source under the wedge load test method, and after the test is completed, the thread of the full thread stud is inspected, if the crack source is found in the thread root, it indicates that the thread strength of the full thread stud is insufficient;

[0009] 3, through the test method can be clear to know the deformation of the full thread stud after the test, if the full thread stud thread occurs shrinkage phenomenon, namely length changes, shows that the overall strength of the full thread stud is insufficient, does not meet the requirements;

[0010] 4, through the present application can find the full thread stud manufacturing defects, provide more accurate full thread stud performance evaluation, early detection of failure problems. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is the lower fixture structure schematic diagram.

[0012] 1 is full thread stud;2 is the fixture body;3 is the thread wedge pad;4 is the support pad;5 is the threaded hole;6 is the chamfer;7 is the support pad inner hole;W is the bevel. DETAILED DESCRIPTION

[0013] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings. Figure 1 The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0014] Embodiment 1 refers to Figure 1 A wedge load test device for full thread stud, comprising an upper fixture and a lower fixture, the lower fixture comprises a fixture body 2, a thread wedge pad 3 and a support pad 4, a threaded cavity is provided in the upper fixture for screwing the thread of the upper end of the full thread stud 1;A lower cavity is provided in the fixture body, the opening of the lower cavity is a first inclined surface, the outer wall of the support pad is a second inclined surface matched with the first inclined surface, the support pad is arranged at the opening of the lower cavity and passes through the lower end of the full thread stud, the lower end of the full thread stud passes through the threaded hole 5 of the thread wedge pad in the lower cavity, and the thread wedge pad has a bevel W;

[0015] S1: the upper fixture is installed on the upper cross beam of the testing machine, and the lower fixture is installed on the lower cross beam of the testing machine;

[0016] S2: the upper end of the full thread stud is screwed into the upper fixture, the screwing length is not less than the thread diameter of the full thread stud, the lower end of the full thread stud passes through the support pad and is screwed into the threaded hole of the thread wedge pad, the screwing length is not less than the thread diameter of the full thread stud, and at the same time, it is confirmed that the length of the gap in the upper fixture and the lower fixture is not less than 6 times the pitch length;

[0017] S3: move the upper cross beam of the testing machine, so that the full thread stud is subjected to tensile force, at this moment, due to the bevel of the thread wedge pad, the full thread stud is subjected to bending force, when the tensile force acting on the full thread stud reaches the maximum load value, the full thread stud does not break, and it is determined that the strength of the full thread stud meets the performance requirements.

[0018] A wedge load test device for a full thread stud, the lower end of the full thread stud passes through the inner hole 7 of the support pad, the inner hole diameter of the support pad is larger than the diameter of the full thread stud.

[0019] A wedge load test device for a full thread stud, the hardness of the thread wedge pad is above HRC45.

[0020] A wedge load test device for a full thread stud, the hardness of the clamp body and the support pad is above 50HRC.

[0021] A wedge load test device for a full thread stud, the first thread of the thread hole of the thread wedge pad is counterbored to facilitate the removal of the broken bolt.

[0022] A wedge load test device for a full thread stud, the design matching angle of the clamp body and the support pad is mainly used for automatic centering during wedge load testing, to avoid the force applied by the testing machine being consumed by the clamp body and the support pad during wedge load testing, without being applied to the full thread stud body. The inner hole 7 of the support pad is larger than the diameter of the bolt, to avoid the full thread stud being stopped by the inner hole of the support pad during the bending stress test, consuming the force applied by the testing machine.

[0023] A wedge load test device for a full thread stud, the effective length of the first thread of the thread hole of the thread wedge pad is not less than the diameter of the full thread stud.

[0024] A wedge load test device for a full thread stud, the oblique angle of the thread wedge pad is matched according to the diameter of the full thread stud, wherein when the diameter of the full thread stud is metric M5-M24, a thread wedge pad with an oblique angle of 6° is used.

[0025] A wedge load test device for a full thread stud, the oblique angle of the thread wedge pad is matched according to the diameter of the full thread stud, wherein when the diameter of the full thread stud is greater than M24, a thread wedge pad with an oblique angle of 4° is used.

[0026] A wedge load test device for a full thread stud, which can quickly evaluate the load bearing capacity of the full thread stud under bending force;

[0027] A wedge load test device for a full thread stud, if the thread strength is insufficient, the defects on the thread surface will tear and form crack sources under the multiple wedge load test method. After the test is completed, the appearance of the thread of the full thread stud is inspected, and if crack sources are found in the thread root, it indicates that the thread strength of the full thread stud is insufficient;

[0028] A wedge load test device for a full thread stud, through this test method, the deformation of the full thread stud after testing can be clearly known. If the thread of the full thread stud has a diameter reduction phenomenon, i.e., the length changes, it indicates that the overall strength of the full thread stud is insufficient and does not meet the requirements.

[0029] The wedge load test device of the full thread stud can find the manufacturing defects of the full thread stud, and provide more accurate performance evaluation of the full thread stud, and early find failure problems.

[0030] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A wedge load testing device for a full thread stud, characterized by: The clamp comprises an upper clamp and a lower clamp, the lower clamp comprises a clamp body (2), a threaded wedge pad (3) and a supporting pad (4), and a threaded cavity is arranged in the upper clamp to screw the thread of the upper end of a full-thread stud (1); a lower cavity is arranged in the clamp body, the opening of the lower cavity is a first inclined surface, the outer wall of the supporting pad is a second inclined surface matched with the first inclined surface, the supporting pad is arranged at the opening of the lower cavity and passes through the lower end of the full-thread stud, the lower end of the full-thread stud passes through a threaded hole (5) of the threaded wedge pad in the lower cavity, and the threaded wedge pad has an inclined angle.

2. A wedge load testing device for a full thread stud as defined in claim 1, wherein: The lower end of the full-thread stud passes through an inner hole (7) of the supporting pad, and the diameter of the inner hole of the supporting pad is greater than the diameter of the full-thread stud.

Images