JP2022116417A - Small creep test piece mounting jig - Google Patents

Abstract

To provide a small creep test piece jig suitable for use in measuring creep elongation of a small test piece having a size smaller than a standard or a different shape by using a conventional creep tester, a grip unit, and an elongation meter.SOLUTION: A small creep test piece mounting jig includes: jig gripping units 31a, 31b capable of being fixed to gripping units 21a, 21b provided in a creep tester 20; jig flange units 32a, 32b for being mounted onto an elongation measuring device provided in the creep tester 20; and intermediate gripping units 33a, 33b capable of fixing gripped units 42a, 42b of a small test piece 40.SELECTED DRAWING: Figure 2A

Description

The present invention relates to a small creep test piece jig suitable for use in measuring the creep elongation of small test pieces having dimensions smaller than the standard or different shapes using conventional creep testers, grips, and extensometers. .

Non-Patent Document 1 Japanese Industrial Standard JIS Z2271 "Methods for creep and creep rupture test of metal materials", Annex JA, measures the creep elongation of metal materials heated to a specified temperature, and obtains stable test results A flanged circular cross-sectional test piece having a parallel portion diameter of 6 mm or more is specified, suitable for use in.
FIG. 6 is a structural front view showing an example of a flanged circular cross-sectional test piece specified in the annex of JIS Z2271. A flanged circular cross-section test piece 10 is composed of a parallel portion 11 used for measuring creep elongation, a flange portion 12 for attaching an extensometer to the test piece 10, and a grip portion 13 for fixing the test piece 10 to a creep tester. be done.

The parallel portion 11 has, for example, a circular cross section 11a, and the diameter of the parallel portion is 6 mm, 8 mm, or 10 mm.
The shape of the collar portion 12 has, for example, a top outer diameter greater than the diameter of the parallel portion 11, for example 10 mm, for example 12 mm. That is, a typical flange 12 has a cross-sectional top height of 1 mm and an inclination angle of the top of, for example, 45 degrees in both vertical directions along the central axis direction of the test piece. The flange portion 12 is provided at two locations on the parallel portion 11, and the interval between the flange portions 12 is regarded as a gauge length that serves as a reference for measuring creep elongation, and is defined to be five times the diameter of the parallel portion. there is
The gripping portions 13 are rod-shaped portions provided at both ends of the flanged circular cross-sectional test piece 10, have a shape thicker than the parallel portions 11, and are fixed to the creep tester.
Conventionally, the test piece 10 is fixed to the grip of a creep tester that matches the test piece 10 of specified size and shape, and an extensometer suitable for the test piece 10 of the specified size and shape is attached to the test piece 10. The elongation of the test piece 10 was measured by attaching it directly to the flange portion 12 and taking it out of the heating apparatus using an extensometer.

FIG. 7 is an overall configuration diagram of a conventional creep tester disclosed in Non-Patent Document 2. As shown in FIG. A conventional creep tester stores a test piece inside an electric furnace, heats it to a specified temperature, and measures the creep elongation. For temperature measurement, a thermocouple is used whose temperature-measuring end is in contact with the test piece. An extensometer, also called an elongation measuring device, measures the elongation of a test piece placed inside an electric furnace with a linear gauge provided outside the electric furnace. The linear gauges are provided on both the left and right sides of the test piece 10, and by averaging the measured values of the left and right linear gauges, the creep elongation is measured more accurately.

FIG. 8 is a main part configuration diagram showing an example in which a flanged circular cross-section test piece specified in the appendix of JIS Z2271 is attached to a creep tester, (A) is a front view showing the upper part of the creep tester, (B) is a plan view at the position of arrow A in FIG. 8(A), and (C) is a front view showing the lower part of the creep tester.
The creep tester 20 includes grip portions 21a and 21b, an upper extensometer shoulder portion 22, a lower extensometer shoulder portion 23, an upper extensometer arm 24, a lower extensometer arm 25, a heating device (electric furnace) 26, and an upper extensometer. It has an adjusting screw 27 , a lower extensometer gauge holder 28 , and a linear gauge 29 .

When mounting a circular section test piece with a flange on a creep tester, follow the procedure below. As shown in FIG. 8A, the male-threaded upper and lower gripping portions 13 of the test piece and the female-threaded upper and lower gripping portions 21a and 21b of the creep tester are combined and fixed. Next, the upper extensometer shoulder portion 22 and the lower extensometer shoulder portion 23 are attached to the flange portion 12 of the test piece by sandwiching it from both the left and right sides of the test piece, and the upper extensometer arm 24 and the lower extensometer arm 25 are passed through and the test piece parallel The extension of the portion 11 is taken out to the outside of the heating device 26 .
Then, the elongation measuring device and linear gauge of the creep tester are combined with the upper part of the creep tester shown in FIG. .
As shown in FIG. 8(C), in the elongation measuring device and linear gauge of the creep tester, the change in the distance between the adjustment screw 27 of the upper extensometer and the gauge holder 28 of the lower extensometer is measured by a dial gauge or a linear gauge. By measuring the length at 29, the elongation of the test piece parallel portion 11 is measured.

Non-Patent Documents 2 and 3 also introduce the conventional specified dimensions and shape of the test piece and the method of fixing the specified test piece to the creep tester. In addition, Patent Document 1, for example, proposes the shape of a creep test piece of a thin metal plate.

Patent No. 6010733

Japanese Industrial Standard JIS Z2271 "Methods for creep and creep rupture testing of metallic materials" Annex JA (regulation) test piece for obtaining stable characteristic values Toshio Ohba, Kota Sawada, Kazuhiro Kimura: "Creep Data Sheet", Metal, Vol. 81, (2011), No. 12, pp. 1006-1015 (P1011 "Test piece shape", P1011-1013 "Test method (procedure)") Shuji Taira: 1962 Creep Test Technology Research Association Joint Research Report Lecture, Tetsu to Hagane, Vol. 51, (1965), pp. 271-285

However, when measuring the creep elongation of a metal material that is too small or has a different shape to make it impossible to obtain a circular cross-section test piece with a parallel part diameter of 6 mm or more, it is necessary to adjust the size and shape of the small test piece that is produced. It was necessary to prepare an extremely expensive dedicated testing machine and gripper. For example, when creating test pieces from platinum-based metals or rare-earth metal elements, platinum-based metals and rare-earth metal elements are used after finishing them into the shape of standard circular cross-section test pieces with flanges. However, since procurement costs increase, testing with small test pieces is desired. When measuring the creep strength of plate-shaped members with a thickness of 6 mm or less, tubular members with a wall thickness of 6 mm or less, and rod-shaped or wire-shaped members with a diameter of 6 mm or less, only small test pieces can be used.
In addition, it is necessary to prepare a new, extremely expensive extensometer suitable for the size and shape of the small test piece, or to implement another method of detecting creep elongation without using an extensometer and extracting it from the heating device. was there.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by using conventional creep testers, grips and extensometers to measure the creep elongation of small test specimens that are smaller than standard or have different shapes. It is an object of the present invention to provide a suitable small creep test piece jig.

[1] A jig for mounting a small creep test piece according to the present invention comprises, for example, as shown in FIG. It has a jig flange 32 for attachment to an elongation measuring device provided in the machine 20, and an intermediate gripping portion 33 to which gripped portions 42a and 42b of the small test piece 40 can be fixed.

[2] In the small creep test piece mounting jig according to the present invention, as shown in FIG. Each of the small creep test piece mounting jigs 30a and 30b is configured to be fixed to the upper and lower grip portions 21a and 21b provided in the creep tester 20. I hope you are.
[3] In the jig for mounting a small creep test piece according to the present invention, preferably, the flange portion 32 of the jig has a cross-sectional top height of 0.5 to 1 mm, and an inclination angle of the top that is It is preferable to have 30 to 60 degrees in the vertical direction along the central axis direction of the one-sided mounting jigs 30a and 30b.
[4] In the jig for mounting a small creep test piece according to the present invention, preferably, the jig gripping portion 31 has a male thread formed on its peripheral surface, and the upper and lower gripping portions 21a and 21b of the creep tester 20 It may be configured to be screwed with the formed internal thread.

[5] In the jig for mounting a small creep test piece according to the present invention, as shown in FIGS. A female thread is formed in the intermediate gripping portion 33, and the male thread of the small test piece 40 and the female thread of the intermediate gripping portion 33 are preferably configured to be screwed together.
[6] In the small creep test piece mounting jig according to the present invention, as shown in FIG. , 42b are formed with through holes, and the intermediate gripping portion 33 is provided with a slit 35 in which the gripped portions 42a, 42b are mounted, and has a lateral hole 36 into which a pin 37 is inserted, When the grasped portion of the small test piece 40 is attached to the slit 35, the lateral hole 36 and the through hole face each other. are fixed to the small creep test piece mounting jigs 30a and 30b.

Using a conventional creep tester, grip part, and extensometer for measuring the creep elongation of a flanged circular cross-section test piece with a parallel part diameter of 6 mm or more specified by the annex of the Japanese Industrial Standard JIS Z2271, it is smaller than the standard It is possible to measure the creep elongation of small specimens of different sizes and shapes.
It is no longer necessary to prepare a very expensive dedicated tester and gripper that match the size and shape of the small test piece. In addition, we prepared a new, extremely expensive extensometer suitable for the size and shape of small test pieces, and implemented another method of detecting creep elongation without using an extensometer and extracting it outside the heating device. no longer need to.

1 is a structural perspective view showing an embodiment of a jig for mounting a small creep test piece of the present invention; FIG. FIG. 1 is a main part configuration diagram showing an example in which a small test piece is mounted on a creep tester using the jig for mounting a small creep test piece of the present invention, and is a front view showing an upper portion of the creep tester. FIG. 2B is a plan view at the position of arrow B in FIG. 2A; A graph showing an example of measuring the change in creep elongation over time of a small test piece using the jig for mounting a small creep test piece of the present invention, showing the case of a small circular cross-section test piece with a parallel part diameter of 3 mm and no collar. be. FIG. 3 is a configuration perspective view showing another embodiment of the small creep test piece mounting jig of the present invention. FIG. 5 is a graph showing an example of the change in creep elongation over time of a flangeless small circular cross-section test piece having a parallel portion width of 3 mm and a thickness of 2 mm using the jig of the example shown in FIG. 4 . 1 is a structural front view showing an example of a flanged circular cross-sectional test piece specified in the annex of JIS Z2271. FIG. 1 is an overall configuration diagram of a conventional creep tester disclosed in Non-Patent Document 2. FIG. It is a front view which shows the upper part of a creep test machine. It is a top view in the arrow A position of FIG. 8A. It is a front view showing the lower part of the creep tester, and is a main part configuration diagram showing an elongation measuring device and a linear gauge of the creep tester.

The present invention will be described below with reference to the drawings.
FIG. 1 is a structural perspective view showing an embodiment of a small creep test piece mounting jig according to the present invention.
In the figure, the jig for mounting a small creep test piece of the present invention comprises a jig gripping portion 31, a jig flange portion 32, and an intermediate gripping portion 33. FIG. A set of two small creep test piece mounting jigs is used to mount both ends of the small creep test piece.
The grip portion 31 of the jig has a shape to be screwed with the upper and lower grip portions 21a and 21b of the creep tester. For example, if the grip portion of the creep tester has a female thread, it should be a male thread so that it can be combined with it.

The shape of the flange portion 32 is preferably the same as the shape of the flange portion 12 of the flanged circular cross-sectional test piece specified in the appendix of JIS Z2271, for example. That is, the top height of the cross section of a typical flange 32 is 1 mm, and the inclination angle of the top is, for example, 45 degrees in the vertical direction along the central axis direction of the test piece. An upper extensometer shoulder portion 22 and a lower extensometer shoulder portion 23 are attached to the flange portion 32 by sandwiching the jig for mounting a small creep test piece from both left and right sides.
The intermediate gripping portion 33 is provided with a cylindrical recess so that a small test piece can be fixed. For example, if the gripping portion of the small test piece has a male thread, the intermediate gripping portion 33 may have a female thread to be screwed therewith.

FIG. 2 is a schematic diagram showing an example of a small test piece mounted on a creep tester using the jig for mounting a small creep test piece of the present invention. FIG. 2B is a plan view at the position of arrow B in FIG. 2A. In addition, in FIG. 2, the same reference numerals are given to the parts having the same functions as those in FIG. 8, and the description thereof will be omitted. Also, the lower part of the creep tester is the same as in FIG. 8C.

The small creep test piece mounting jig of the present invention is used between the clamps 21a, 21b and the small test piece 40 of a conventional creep tester. The small creep test piece mounting jigs 30a and 30b of the present invention are composed of jig gripping portions 31a and 31b, jig flange portions 32a and 32b, and intermediate gripping portions 33a and 33b.
The small test piece 40 preferably has a shape similar to a collarless circular cross-section test piece defined in the annex of JIS Z2271, for example, and includes a parallel portion 41 and gripped portions 42a and 42b. The diameter of the parallel portion 41 may be, for example, 2 to 4 mm, and the length of the parallel portion 41 may be, for example, 10 to 30 mm so that the elongation measurement of the creep tester can be performed accurately. The gripped portions 42 a and 42 b are provided at both ends of the small test piece 40 , and preferably have a structure to be screwed together with the intermediate grip portion 33 .

When the small test piece 40 is mounted on the creep tester using the small creep test piece mounting jig, the procedure is as follows. The jig gripping portions 31a, 31b and the upper and lower gripping portions 21a, 21b of the creep tester are combined and fixed. Next, the intermediate gripping portions 33a and 33b are combined with the gripped portions 42a and 42b of the small test piece and fixed.
Furthermore, the upper extensometer shoulder portion 22 and the lower extensometer shoulder portion 23 are attached to the jig collar portions 32a and 32b by sandwiching the small creep test piece mounting jigs 30a and 30b from both left and right sides. The elongation of 41 is taken out of the heating device 26 .

Then, the elongation measuring device and linear gauge of the creep tester are combined with the upper part of the creep tester shown in FIG. .
As shown in FIG. 8(C), in the elongation measuring device and linear gauge of the creep tester, the change in the distance between the adjustment screw 27 of the upper extensometer and the gauge holder 28 of the lower extensometer is measured by a dial gauge or a linear gauge. By measuring the length at 29, the elongation of the parallel portion 41 of the small test piece 40 is measured.

The heating device 26 is heated to a predetermined creep measurement temperature, eg, 300 to 1000° C., and the small creep test piece mounting jigs 30a and 30b including the small test piece 40 are held at the creep measurement temperature. Then, a predetermined creep measurement load is applied to the small creep test piece mounting jig including the small test piece 40, and the creep elongation of the small test piece 40 is measured over time to obtain a creep elongation measurement curve. Preferably, the time to creep rupture of the small test piece 40 is measured, and the creep rupture life to the creep measurement temperature is measured.

<Example 1>
FIG. 3 is a graph showing an example of the change in creep elongation over time of a flangeless small circular cross-section test piece with a parallel portion diameter of 3 mm using the jig of the present invention. The gripped portions 42a and 42b of the small test piece 40 having male threads were combined and fixed to the intermediate gripping portions 33a and 33b having female threads. Then, the jig flanges 32a and 32b are sandwiched from the left and right sides of the small creep test piece mounting jigs 30a and 30b by the upper extensometer shoulder portion 22 and the lower extensometer shoulder portion 23, and the elongation of the creep tester is measured. Attach to the measuring device. The creep elongation of the parallel portion 41 of the small test piece 40 was measured by taking it out of the heating device 26 by the elongation measuring device of the creep tester.
As shown in FIG. 3, a creep elongation of about 3 mm can be measured after about 3.5 hours of elapsed time.

<Example 2>
FIG. 4 is a structural perspective view showing another embodiment of the small creep test piece mounting jig of the present invention.
In this embodiment, a jig 30a for mounting a small creep test piece has a jig gripping portion 31, a jig collar portion 32, a slitted intermediate gripping portion 34, a slit 35, a lateral hole 36, and a pin 37. FIG.
The plate-shaped small test piece 40 is provided with a through hole at a position facing the lateral hole 36 when inserted into the slit 35 of the small creep test piece mounting jig 30a.

In the device configured as described above, a small plate-shaped test piece 40 is inserted into the slit 35 of the intermediate grip portion 34 . When the plate-shaped small test piece 40 is inserted into the slit 35 , the pin 37 is passed through the lateral hole 36 , and the plate-shaped small test piece 40 can be sandwiched between the intermediate grips 34 and fixed.

FIG. 5 is a graph showing an example of the change in creep elongation over time of a flangeless small circular cross-section test piece with a parallel portion width of 3 mm and a thickness of 2 mm using the jig of the example shown in FIG. A creep elongation of about 1 mm can be measured after about 100 hours of elapsed time.

According to the small creep test piece jig of the present invention, it is possible to measure the creep elongation of small test pieces having sizes smaller than the standard or different shapes using existing creep testers, grips, and extensometers.

10 Circular section test piece with flange 11 Parallel part 12 Flange part 13 Gripped part 20 Creep tester 21a, 21b Gripping part 22 Upper extensometer shoulder part 23 Lower extensometer shoulder part 24 Upper extensometer arm 25 Lower extensometer arm 26 Heating Equipment (electric furnace)
29 Linear gauges 30, 30a, 30b Small test piece mounting jigs 31, 31a, 31b Jig gripping portions 32, 32a, 32b Jig flanges 33, 33a, 33b Intermediate gripping portion 34 Intermediate gripping portion with slit 35 Slit 37 Pin 40 Small test piece 41 Parallel parts 42a, 42b Gripped part

Claims (6)

a jig grip portion that can be fixed to a grip portion provided in the creep tester;
a jig collar for attachment to an elongation measuring device provided in the creep tester;
an intermediate gripping portion capable of fixing the gripped portion of the small test piece;
A jig for mounting a small creep test piece. The jig for mounting the small creep test piece is mounted on each of the gripped portions located at both ends of the small test piece,
2. The small creep test piece mounting jig according to claim 1, wherein each of said small creep test piece mounting jigs is configured to be fixed to upper and lower grips provided on said creep tester. The flange of the jig has a top height of 0.5 to 1 mm in cross section, and an inclination angle of the top of 30 to 60 degrees in both vertical directions along the central axis direction of the jig for mounting the small creep test piece. A jig for mounting a small creep test piece according to claim 1 or 2. 4. The jig gripping portion according to any one of claims 1 to 3, wherein a male thread is formed on a peripheral surface of the jig gripping portion and configured to be screwed with a female thread formed on the upper and lower gripping portions of the creep tester. A jig for mounting a small creep test piece described in . A male thread is formed on the peripheral surface of the gripped portion of the small test piece,
A female thread is formed in the intermediate grip portion,
5. The jig for mounting a small creep test piece according to claim 1, wherein the male thread of the small test piece and the female thread of the intermediate gripping portion are screwed together. The small test piece is a plate-shaped gripped portion, and a through hole is formed in the gripped portion,
The intermediate gripping portion is provided with a slit to which the gripped portion is attached, and has a lateral hole into which a pin is inserted,
When the gripped portion of the small test piece is attached to the slit, the lateral hole and the through hole face each other, and when the pin is attached to the lateral hole and the through hole, the small test piece is The small creep test piece mounting jig according to any one of claims 1 to 4, wherein the small creep test piece mounting jig is configured to be fixed to the small creep test piece mounting jig.

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