JPS626512Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is applicable to tests for determining the circumferential strength of pipe materials at room and high temperatures, such as tensile tests, creep tests, creep rupture tests, and fatigue tests.
This article relates to a jig for tensile testing of pipe materials.

Conventionally, circumferential tensile tests of tube materials have been conducted using jigs as shown in FIGS. 1 and 2.

Reference numeral 1 is a test piece in which the test tube material is cut into rounds, and the cross-sectional areas in the tube axis direction of the test parts 1a and 1b that face each other on the same circumference are the remaining untested parts 1c and 1b that face each other on the same circumference. It is processed so that the cross-sectional area in the tube axis direction is smaller than 1d. 2 and 3 are cores that are inserted into the test piece 1 so as to be almost in contact with the inner circumferential surface of the test piece 1, and are divided into two halves in a semi-cylindrical shape on a plane including the axis, with pin holes 2a and 3a drilled in the center, respectively. . pin hole 2
The pins 6, 7 inserted into the cores 2, 3a
These are connected to one ends of tension jigs 4 and 5 that pull in opposite directions so that the dividing surfaces of the two are separated from each other. Further, the other ends of the tensioning jigs 4 and 5 are connected to a loading device (not shown) that applies a tensile load W to the test piece 1 via the tensioning jigs 4 and 5 and the cores 2 and 3.

Conventional jigs are configured like this, so
When inserting the cores 2 and 3, which are divided into two along a plane including the axis, so that they are almost in contact with the inner peripheral surface of the test piece 1, and pulling them in opposite directions so that the divided surfaces are separated from each other, the cores 2 and 3 are separated. The outer peripheral parts 2d and 3d of 3 are test piece 1
almost the entire inner circumferential surface of the cylinder is contacted, and a force in the opposite direction is applied.
As a result, a tensile load W is applied to the test piece 1 along the circumferential direction, and a tensile load W equally divided into two acts on the opposing test portions 1a and 1b along the circumferential direction.

Therefore, when the tensile load W is increased, test piece 1 finally
The test parts 1a and 1b are destroyed. The required tensile strength in the inner circumferential direction of the test piece 1 was determined from this load up to the time of failure.

As mentioned above, in the conventional jig, it is necessary to pass the pins 6 and 7 through the cores 2 and 3, which are divided into two parts, and the cores 2 and 3 are naturally limited in size, and the diameter of the test piece 1 It has the disadvantage that it cannot be applied when is small.

The present invention eliminates these drawbacks, and includes a test jig for testing the tensile strength of pipes in the circumferential direction, which includes a shaft core inserted so as to be almost in contact with the inner circumferential surface of the pipe test piece. It consists of a core divided into two parts by a plane, and means for matingly engaging both end faces of the core and pulling them in opposite directions so that the faces divided by the plane containing the axis are separated from each other. The purpose of the present invention is to provide a jig that can perform a tensile test regardless of the diameter of the test piece.

As described above, in the jig of the present invention, a cylindrical core to be inserted into a tube test piece is divided into two by a plane including the axis. Then, the core divided into two parts was inserted into a test piece, and the two parts divided along a plane including the axis were pulled in opposite directions by appropriate means.

Therefore, with the jig of the present invention, there is no need to insert a pin into the core, so even if the tube diameter of the test piece is small, it is possible to perform a tensile test.

Hereinafter, one embodiment of the jig for tensile testing of pipe materials according to the present invention will be described as shown in FIGS. 3 and 4.

10 is a test piece in which the test tube material was cut into rings;
Processed so that the cross-sectional area in the tube axis direction of the test portions 10a and 10b facing each other on the same circumference is smaller than the cross-sectional area in the tube axis direction of the remaining untested portions 10c and 10d facing each other on the same circumference. has been done. 30,50
is a core inserted so as to be almost in contact with the inner circumferential surface of the test piece 10, and divided into two semi-cylindrical shapes on a plane including the axis, and has engaging portions 30a and 50a on both end surfaces, respectively.
are provided in a protruding manner and are fitted and locked into the mounting holes 20a, 40a of the mounting members 20, 40, respectively. The mounting members 20 and 40 have bolts 80 and 90 attached to one ends of tension jigs 60 and 70, respectively, which pull the split surfaces of the cores 30 and 50 in opposite directions so that they separate from each other.
and are connected via nuts 80a and 90a. Further, the other ends of the tensioning jigs 60, 70 are connected to a loading device (not shown) that applies a tensile load W to the test piece 10 via the tensioning jigs 60, 70 and the cores 30, 50.

Since the present embodiment is configured in this way, the cores 30 and 50, which are divided into two on a plane including the axis, are inserted so as to be almost in contact with the inner peripheral surface of the test piece 10, and the divided surfaces are separated from each other. When the cores 30 and 50 are pulled in opposite directions, the outer circumferences of the cores 30 and 50 become 30d and 50d.
0d contacts almost the entire inner peripheral surface of the test piece 10, and a force in the opposite direction is applied. As a result, a tensile load W is applied to the test piece 10 along the circumferential direction, and a tensile load W equally divided into two acts on the opposing test portions 10a and 10b along the circumferential direction.

Therefore, when the tensile load W is increased, the test portions 10a and 10b of the test piece 10 finally break. Therefore, the required tensile strength of the test piece 10 in the circumferential direction can be determined from the load up to the time of failure.

As described above, according to the jig of this embodiment, even when the inner diameter of the test piece 10 is small and it is impossible to provide a pin hole inside the core, the test piece 1
It becomes possible to perform a test to determine the tensile strength in the circumferential direction of 0.

In addition, in the above examples, taking into account thermal expansion during high temperature tests such as creep tests, the test piece 10
A slight gap may be provided between the inner peripheral surface of the core 30 and the like.

Furthermore, when the two divided cores 30 and 50 are pulled in opposite directions so as to separate from each other at the dividing plane, the corners of the two cores 30 and 50 are pulled into the test piece.
If there is a risk of contacting and damaging the inner circumferential surface of the core 0, the corners of the core 30 or 50 may be rounded, if necessary.

[Brief explanation of the drawing]

Figure 1 is a side view of a conventional tensile test jig, Figure 2
The figures are a cross-sectional view taken along the - line in Fig. 1, Fig. 3 is a side view of an embodiment of the present invention, and Fig. 4 is a longitudinal sectional view taken along the - line in Fig. 3. be. 10: test piece, 10a, 10b: test piece part, 20, 40: mounting member, 30, 50: core, 60, 70: tension jig, 80, 90: bolt, 80a, 90a: nut, W: tensile load.

Claims (1)

[Scope of utility model registration request] In a test jig used for tensile strength testing in the circumferential direction of pipe material, a core divided into two by a plane containing an axis inserted so as to be almost in contact with the inner circumferential surface of a pipe material test piece, and the same core. 1. A jig for tensile testing of a tube material, comprising means for pulling the core in opposite directions so that the surfaces that are divided by a plane that includes the axis and that are engaged with both end surfaces of the core are separated from each other.