JPH04134052U - Fixation structure of test piece to load bearing shaft of high temperature creep tester - Google Patents

Abstract

(57) [Summary] [Purpose] To facilitate the removal of test specimens after performing creep tests using a high-temperature creep tester. [Structure] After setting the half nut 2 in the space 3c of the cap nut 3, the load bearing shaft 4 on the testing machine side is screwed into the cap nut 3. After that, the male screws 1 provided at both ends of the test piece 1
c is screwed into the half nut 2 to fix the test piece 1, and a high temperature creep test is performed by applying a tensile load. [Effect] Even if the half nut 2 and test piece 1 are oxidized and seize during a long-term high-temperature creep test, the space 3c remains intact.
After taking it out, it can be easily separated by cutting off the joint surface 2b of the half nut 2.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention allows for easy removal even if the threads provided at both ends of the test piece become oxidized. This is related to the structure for fixing the test piece to the load-bearing shaft of the high-temperature creep tester. be.

0002

[Conventional technology]

Conventionally, the test piece 1 used in the creep test is as shown in Figure 2 (a) and (b). It consists of a cylindrical parallel part 1a and both end grip parts 1b having a larger diameter than the parallel part 1a. Ru. A male thread 1c is cut on the outer peripheral surface of the grip part 1b, and the height is as shown in FIG. At the female threaded portion 3'a of a pair of cap nuts 3' placed opposite the warm creep tester, It is screwed into place and a tensile load can be applied to both ends.

0003

[Problem that the idea aims to solve]

When performing a high-temperature, long-term creep test using the above method, the Due to the oxidation of the girder threaded portion 1c, the test piece 1 and the cap nut 3' cannot be removed. this As a means to prevent baking due to oxidation, apply an antioxidant before testing. However, this antioxidant is not suitable for short-term tests such as high-temperature tensile tests. It is effective when performing tests at high temperatures for long periods of time, such as creep tests. has no effect.

0004 In other words, Figure 4 shows that in the conventional high-temperature creep test, an antioxidant was added to the test piece. The specimen cannot be separated after the creep test for coated and uncoated specimens. It is a diagram showing the relationship between temperature and test time, where (a) in FIG. 4 is for carbon steel and (a) is for carbon steel; (b) shows the case of 3Cr to 9Cr steel. From (a) and (b) in Figure 4, the charcoal Antioxidant coating has no effect on either raw steel or 3Cr to 9Cr steel. However, it has the disadvantage that it generates harmful gases and makes the test environment worse.

[0005]

[Means to solve the problem]

This invention was made in view of the above-mentioned circumstances, and its gist is as follows. As written. In other words, the present invention is installed in a high-temperature creep tester, and a pair of load-bearing shafts each having a male thread, and a screw in the male thread of each load-bearing shaft; It has a female thread on one side, and the gripping parts at both ends of the test piece are inserted into the other side. an opening between the female thread and the opening, the diameter of which is smaller than the diameter of the female thread; a cap nut having a space formed with a diameter larger than the diameter of the cap nut; A half-split nut set in A high-temperature creep test characterized by consisting of a test piece each having a male thread screwed into it. This is the structure in which the test piece is fixed to the load bearing axis of the test.

[0006]

【Example】

Hereinafter, the structure and operation of the present invention will be explained in detail based on examples. In Figure 1 The test piece 1 has a cylindrical parallel part 1a and gripping parts at both ends that have a larger diameter than the parallel part 1a. 1b, and the grip part 1b has a male thread 1c, which is basically the same as the conventional example. It is the same.

[0007] In this invention, a pair of loads installed in a high temperature creep tester (not shown) A male thread 4a is provided at each end of the load shaft 4. 3 is a cap nut; The nut 3 has a female thread 3a on one side into which the male thread 4a of the load bearing shaft 4 is screwed. and has an opening 3b on the other side through which the both end gripping parts 1b of the test piece 1 are inserted, Between the female thread 3a and the aperture 3b, there is a thread smaller than the diameter of the female thread 3a and smaller than the diameter of the aperture 3b. A space 3c having a large diameter is also formed. and female screws 3a with different diameters. , the space 3c and the aperture 3b communicate in a stepped manner.

[0008] On the other hand, the half nut 2 is housed in the space 3c formed in the cap nut 3. The female thread 2a of the half nut 2 has a male thread provided on the both end gripping portions 1b of the test piece 1. 1c is screwed into it. Next, I will explain the installation and removal procedures for test piece 1. After storing and setting the half nut 2 in the space 3c formed in the cap nut 3, The male thread 4a of the load bearing shaft 4 is screwed into the female thread 3a on the other side. After that, test piece 1 Screw the male thread 1c provided on both end grip portions 1b into the female thread 2a of the half nut 2. Fix it, apply a tensile load and perform a high temperature creep test, or After storing the half nut 2 in the space 3c, the male thread 1c of the test piece 1 is inserted into the half nut 2. and then screw the female thread 3a of the cap nut 3 onto the male thread 4a of the load bearing shaft 4. It is also possible to fix the material in place and apply a tensile load.

[0009] In addition, the procedure for removing test piece 1 after fracture in the high temperature creep test is as follows: Half nut 2 If the female thread 2a of the test piece 1 and the male thread 1c of the test piece 1 loosen easily, remove the screws as they are. Loosen and remove test piece 1. However, the female thread 2a of the half nut 2 and the male thread of the test piece 1 If the screw 1c is stuck due to oxidation and cannot be loosened easily, first tighten the female thread of the cap nut 3. Remove the load bearing shaft 4 by loosening the male screw 4a of the load bearing shaft 4 from the screw 3a. after that , take out the half-split nut 2 from the space 3c of the cap nut 2, and remove the joint divided into two parts in the axial direction. By separating the mating surface 2b, it is easy to remove the specimen 1 even if it is baked by oxidation. I can.

0010 Therefore, according to the creep test using the test piece fixing structure of the present invention, the test piece No stress such as bending is applied, and the conventional problem of high-temperature long-term creep is avoided. Test specimens can be easily attached and detached from the grip during testing, improving workability during creep tests. This will greatly help improve the rate. That is, according to the present invention, the conventional test as shown in FIG. With single-fixed structure, the test piece can be easily removed under all conditions where it is impossible to remove the test piece. Now I can do it.

[0011]

[Effect of the idea]

As explained above, according to the present invention, test results are obtained in high temperature long-term creep tests. without sacrificing accuracy, and eliminates the problem of conventional methods due to oxidation of the gripping part of the specimen. Achieves easy and reliable removal of the test piece without being unable to remove it from the high-temperature creep tester can.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a test piece fixing structure of the present invention.

FIG. 2 is a front view showing the structure of a general test piece.

FIG. 3 is a sectional view showing a conventional test piece fixing structure.

[Figure 4] Diagram showing the relationship between the temperature at which the test piece becomes unable to detach after the creep test and the test time for test pieces coated with antioxidant and those not coated with antioxidant in a conventional high-temperature creep test. and (a) is carbon steel,
(b) is the case of 3Cr to 9Cr steel.

[Explanation of symbols]

1 Test piece 1a Parallel part 1b Both end grips 1c male thread 2 Half nut 2a Female thread 2b Joint surface 3 Cap nut 3a Female thread 3b Open hole 3c Space part 4 Load bearing axis 4a Male thread

Claims (1)

[Scope of utility model registration request] 1. A pair of load-bearing shafts disposed in a high-temperature creep tester, each having a male thread at its tip, and a female thread on one side to be screwed into the male thread of each of the load-bearing shafts,
The other side has apertures through which the gripping portions at both ends of the test piece are inserted, and a space is formed between the female thread and the aperture with a diameter smaller than the diameter of the female thread and larger than the diameter of the aperture. A high-temperature creep test piece comprising a cap nut having a cap nut, a half nut set in a space of the cap nut, and a test piece in which male threads provided at gripping portions at both ends are screwed into the female threads of the half nut, respectively. Structure for fixing the test piece to the load-bearing axis of the test.