JPS626511Y2 - - 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.

The first specimen was a circumferential tensile test specimen of a conventional pipe material.
The figure and FIG. 2 will be explained.

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 the above test pieces 1
The core is inserted so as to be almost in contact with the inner circumferential surface of the core, and is divided into two halves in a semi-cylindrical shape on a plane including the axis, and pin holes 2a and 3a are bored in the center of each core. The pins 6 and 7 inserted into the pin holes 2a and 3a are inserted into the core 2,
The jigs 4 and 5 are connected to one ends of tension jigs 4 and 5 that pull in opposite directions so that the divided surfaces of the 3 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.

Conventionally, the cores 2 and 3 are split into two parts on a plane including the axis, and inserted into the test piece 1 so that they are almost in contact with the inner circumferential surface of the test piece 1, and the split surfaces are separated from each other. When pulled in opposite directions,
The outer peripheral parts 2d and 3d of the cores 2 and 3 are in contact with almost the entire inner peripheral surface of the test piece 1, and a force in the opposite direction is applied thereto. 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 the 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 the value 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 four parts by a plane and a plane orthogonal to the axis, and means for pulling the core in opposite directions so that the divided surfaces separated 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 four parts by a plane including the axis and a plane perpendicular to the axis. Then, the core divided into four parts was inserted from both sides of the test piece, and the 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. Reference numeral 10 is a test piece in which the test tube material is cut into rings, and the test pieces 10 are opposite to each other on the same circumference.
The cross-sectional areas in the tube axis direction of portions a and 10b are processed to be smaller than the cross-sectional areas in the tube axis direction of the remaining untested portions 10c and 10d that face each other on the same circumference.

20, 30, 40, and 50 are cores, which are obtained by dividing a cylindrical body that is almost in contact with the test specimen 10 into four parts by a plane including the axis and a plane perpendicular to the axis. .

Reference numerals 20a, 30a, 40a and 50a are mounting members fixed to semicircular end faces of cores 20 and the like with corresponding symbols, respectively, and the mounting members 20a and 30a are attached to the tension jig 60 and to the mounting member 40a. 50a
are connected to the tension jig 70 by bolts 80, 90 and nuts 80a, 90a, respectively.

Further, the tension jigs 60 and 70 are connected to a loading device (not shown) that applies a tensile load W to the test piece 10.

Since this embodiment is configured as described above, 4
The divided cores 20, 30, 40, and 50 are engaged with the inner circumferential surface of the test piece 10 so as to be almost in contact with the core 2.
The tensioning jigs 60, 70 and bolts 8 are moved in opposite directions so that 0, 30 and 40, 50 are separated from each other.
When pulled through 0.0, 90 and a loading device (not shown), the outer circumference of the core 20 and the like comes into contact with almost the entire inner circumference of the test piece 10, and the cores 20, 30 and 40, 50, which are opposed to each other, Forces in opposite directions act on each other.

As a result, a tensile load W is applied to the test piece 10 along the circumferential direction. In this case, a tensile load W equally divided into two is applied to the sample portions 10a and 10b facing each other on the same circumference of the test piece 10 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 20 and the like.

Furthermore, the cores 20, 30 and 40, which were divided into four,
When the core 20 and the like are pulled in opposite directions so as to separate from each other at the dividing surface, if there is a risk that the corner of the core 20 or the like will come into contact with the inner peripheral surface of the test piece 10 and cause damage, If necessary, the corners of the core 20 and the like can be rounded.

[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 part of test piece, 20, 30, 40, 50: Core, 60, 7
0: Tension jig, 80, 90: Bolt, 80a, 9
0a: nut, W: tensile load.

Claims (1)

[Scope of utility model registration request] A test jig used for tensile strength testing in the circumferential direction of pipe material is divided into four parts by a plane containing the axis inserted so as to be almost in contact with the inner peripheral surface of the pipe material test piece and a plane perpendicular to the axis. A jig for tensile testing of pipe materials, characterized in that the jig is comprised of a core with a cylindrical shape, and means for pulling the core in opposite directions so that the surfaces divided by a plane including the axis of the core are separated from each other. .