JPS59222744A - High temperature tension tester - Google Patents

Abstract

PURPOSE:To prevent the variations of the temperature difference portion in a high temperature testing by arranging a high temperature tank closed with a lid having a test piece mounting device inside and a dissimilar material inserted into a part of the clearance between a pull rod retaining a test piece and a sealed pressure tube. CONSTITUTION:A high temperature chamber 1 contained in an electric furnace 2 is closed with a lid 3 having a test piece mounting ring 5. A sealed pressure tube 9 with a water-cooled jacket 10 is provided outside the lid 3 while a mobile pull rod 11 is inside piercing the lid 3. A dissimilar material 13 is inserted into a part of a clearance 12 between the sealed pressure tube 9 and the pull rod 11 so as to allow a clearance with the pull rod 11. This prevents the generation of a violet convection phenomenon in the clearance 12 to check variations in the force aded to a test piece 14 and the elongation thereof with time thereby a high temperature tension testing at a high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a high-temperature tensile test device, and more particularly to a high-precision high-temperature tensile test device.

[Background of the invention]

In high-temperature tensile equipment, it is not necessary to install the load application mechanism for the test piece and the pressure sealing mechanism installed in the high-temperature chamber on the low-temperature side; instead, there is always a shaft between the mechanism and the high-temperature chamber. There are parts where there is a temperature difference in the direction. In this case, when the high temperature portion is located below and the low temperature portion is located above, convection occurs in the fluid surrounding the temperature difference portion, and this convection thermally deforms the temperature difference portion over time. This thermal deformation has a negative effect on the stress added to the test piece and the elongation of the test piece, resulting in a reduction in test accuracy.

[Purpose of the invention]

In view of the above, it is an object of the present invention to prevent stress added to a test piece and temporal fluctuations in elongation of the test piece, and to improve test accuracy.

[Summary of the invention]

In order to achieve the above object, the present invention provides a high-temperature chamber in which an opening provided on an upper end surface or a lower end surface is closed with a lid having a test piece holder inside, and a high-temperature chamber that is attached to the outside of the lid. A confinement tube provided with a water cooling jacket, and a glu rod inserted into the confinement tube, protruding through the lid into the high temperature chamber, holding the test at the protruding end, and movable in the axial direction. and a sealing mechanism attached to the pull rod and the sealing tube on the side opposite to the high temperature tank;
It is characterized by comprising a foreign material inserted into a part of the gap formed between the pull rod and the sealing tube and having a temperature difference in the axial direction.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a high-temperature tank made of 5US316 that is surrounded by the electric furnace 2 and has an opening 1a on the upper end surface; 3 is a lid that closes the opening 1a of the high-temperature tank 1 via an O-ring 4; A protrusion 3a is provided inside the lid 3.

5 is a test piece mounting ring attached to the tip of the protrusion 3a, 6 is a test piece holder attached to the ring 5 via a nut 7, and 8a, 8b is a test piece mounting device attached to the lid 3. A mother loop connecting pipe 9 is attached to the outer surface of the lid 3 and a sealing tube with a water cooling jacket 10 on the upper part, 11 is inserted into the sealing tube 9 and passes through the lid 3 into the high temperature tank 1. A protruding pull rod 11 is provided so as to be movable in the axial direction.

12 is a gap formed between the sealing tube 9 and the pull rod 11, and a part of this gap 12, that is, a water cooling jacket) 1
A foreign material 13 is inserted into the gap between the lower end of the cover 3 and the lid 3. As this foreign material 13, for example, a stainless wool sintered member is used.
9 stainless steel wire with a diameter of 10μφ is sintered at high temperature. Since the thin wires have a structure in which they are locally bonded to each other, the thin wires are not a fragile material that does not easily peel off, and are an easy material to cut. 14 is a test piece held between one end of the pull rod 11 (lower end in the figure) and the upper end of the test piece holder 6; 15 is a sealing material attached to the top of the confining tube 9;
63 to 16C are between the pull rod 11 and the sealing material 15;
These are O-rings provided between the sealing tube 9 and the sealing material 15 and between the pull rod 11 and the sealing tube 9, respectively.

The pull rod 11 is operated by a stress applying mechanism (not shown).
, are moved up and down to apply stress to the test piece 14. This stress and the amount of displacement (elongation) of the test piece 14 are determined by a load cell (not shown) provided between the stress applying mechanism and the pull rod and a differential transformer (not shown) attached to the upper part of the pull rod 11. It is designed to be measurable.

Using a top-mounted structure (without inserting a foreign material 13 into the gap 12), 85 kg-1/c was passed from the mother loop (not shown) into the high temperature tank 1 through the connecting pipe 8a.
The high temperature bath 1 was maintained at 250C in the electric furnace 2.Then, the pull rod 11 was moved upward by a certain amount, and the test piece 14 was heated at 500 kg-f.
A load was applied to the test piece, and its change over time was measured. The results are shown in Figure 2, which shows that the measured load and elongation changed randomly over time, and the maximum amount of change was 50 kg-f.

In order to understand the reason for the above random changes, a thermocouple 17 was attached to the surface of the sealing tube 9 between the bottom surface of the water cooling jacket 10 and the top surface of the lid 3 of the high temperature tank 1, as shown in FIG. A thermocouple 17 was connected to a temperature recorder 18 via a lead wire 19, and the temperature of the sealing tube 9 was measured.

The measurement results are shown in Figure 4.
o to t3 are temperature distribution curves in the longitudinal direction of the sealing tube 9 at 0, 5, and 12.17 minutes, respectively. It can be seen from FIG. 4 that the temperature inside the sealing pressure tube 9 changes in a complicated manner with time. From the relationship between the fluctuation period, the measured load, and the measured elongation, the gap 1 between the confining pressure tube 9 and the pull rod 11
This is thought to be due to the intense convection phenomenon occurring within 2.

It is understood that thermal deformation of the pull rod 11 or the sealing tube 9 due to thermal fluctuations is reflected in the above phenomenon.

Therefore, in this embodiment, in order to prevent the above phenomenon, a foreign material, that is, a stainless wool sintered member 13 is inserted into a part of the gap 12 between the sealing tube 9 and the pull rod 11 as described above, and the pull rod 11 and A gap of 0.08 m is formed between the sintered member 13 and the sintered member 13.
Even if they come into contact, the sliding resistance is about 1 kg-f.

As a result, the temperature distribution on the outer surface of the confining pressure tube 9 became gentle as shown by the curve to in FIG. 4, and no change with time was observed. Similarly measured load change is 2kg-f
The amount of change in elongation of test piece 14 was below the measurement limit. Therefore, according to this example, the accuracy of the tensile test can be improved, so that it can be applied to 5SRT tests and fatigue tests at high temperatures.

In the above first embodiment, a stainless wool sintered member was used as the foreign material 13, but a ring with high heat insulation properties that is movable or deformable in the axial and radial directions, for example, made of 5US304 stainless steel or Teflon, is used instead. A ring may also be used. This ring has a plate thickness of 0.2 or 0.
8 m, the gap between the ring and the pull rod is 0.4 or 0.1 trtm, and eight rings are provided in this gap in the axial direction, and the load is controlled in the same manner as in the first embodiment. Changes over time were measured.

As a result, in all cases, by providing a ring within the gap, the load fluctuation was reduced to 2 kg-f or less, and an excellent effect was obtained. In particular, the most excellent effect was obtained when a Teflon ring with a thickness of 0.8 was used and the gap between the ring and the pull rod was set to 0.1.

On the other hand, when using a stainless steel ring with a plate thickness of 0.2 mm, the gap between the ring and the pull rod is 0.4 mm.
When it was set to rran, it was observed that the load fluctuation tended to increase.

According to the above results, according to this example, (1) convection is prevented from occurring in the gap between the ring and the pull rod, and (10) convection is prevented from occurring in the gap between the ring and the sealing tube. However, it has been found that the generation of convection can be prevented by making it difficult for the heat change to be transmitted to the pull rod and by reducing the gaps between the sealing tube and the pull rod.

Next, as another example, the cross-sectional shape of the pull rod 11 from the lower part of the water cooling jacket 10 to the lower surface of the high temperature tank lid 3 in the first example (Fig. 1) was formed as shown in Fig. 5. That is, four grooves 20 each having a width of 4 mm and a depth of 2 mm were provided in the pull rod 11 in the axial direction, and a windbreak wall (not shown) was provided on the outside of the sealing tube 9. The rest of the structure is the same as the first embodiment, so drawings and explanations will be omitted.

In such an embodiment, the water temperature is 20:1:0.2C.
Flow rate of VC-regulated water into the water cooling jacket is 300±2
When a test was conducted in the same manner as in the first example by supplying ml/min, the load fluctuation was 2 to 4 kg, f. In this case, the temperature at the outer periphery of the confining pressure tube is the fourth in the axial direction.
As shown by curve 1o in the figure, it changes gently,
In the circumferential direction, it changed to the highest and lowest values every 90 cm. In this case, a convection phenomenon is generated in the gap, but by providing a groove in the pull rod as described above, it is expected that a steady convection is generated, and the time dependence of the thermal deformation of the pull rod is expected to occur. It turns out that there isn't.

The first embodiment has a pull rod 1 that holds a test piece 14.
1 passes through the lid 3 that closes the opening 1a provided on the upper end surface of the high temperature tank 1, and is positioned above the high temperature tank 1.However, in contrast to this, the pull rod is inserted into the lower end surface of the high temperature tank 1. It may be constructed so that it passes through a lid that closes the provided opening and is located below the high temperature bath.

Using this example configured as described above, a test was conducted in the same manner as in the first example, and as a result, the load fluctuation was 0.5 kg-f or less. In addition, in the first embodiment, the load repetition rate was set to 3H.
2, the load variation was 0.8 kg-f, whereas in this example it was still 0.5 kg-f.

This is not because the convection phenomenon is theoretically less likely to occur if the high temperature tank is installed in an upper position, but also because it is possible to prevent the fluid from moving as the pull rod moves.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to prevent stress added to a test piece and time fluctuations in elongation of the test piece, and improve test accuracy.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the high temperature tensile test device of the present invention, Fig. 2 is a view showing the load and elongation during temperature measurement on the outer circumferential surface of the confining tube, and Fig. 3 is a diagram showing the temperature on the outer circumferential surface of the confining tube. FIG. 4 is a diagram showing the measurement method, FIG. 4 is a diagram showing the temperature measurement results on the outer circumferential surface of the confining tube, and FIG. 5 is a sectional view of a pull rod according to another embodiment of the present invention. Engineering...high temperature tank, 1a...opening, 3...lid, 6
...Test specimen fixture, 9...Containment tube, 1o...Water cooling jacket, 11...Pull rod, 12...Gap,
13...Different materials, 1st χ 2nd day 3rd a

Claims (1)

[Scope of Claims] 1. A high-temperature chamber with an opening provided on the upper end surface or the lower end surface closed by a lid having a test piece holder inside, and a water-cooling jacket attached to the outside of the lid. a sealing tube, a pull rod inserted into the sealing tube, protruding into the high temperature chamber through the lid, holding a test piece at the protruding end, and movable in the axial direction; This pull rod and the sealing pressure mechanism attached to the opposite side of the high temperature tank of the sealing tube, and a foreign material inserted into a part of the gap formed between the pull rod and the sealing tube and having a temperature difference in the axial direction. A high temperature tensile test device characterized by: 2. The high-temperature tensile test device according to claim 1, wherein a stainless wool sintered member is used as the foreign material. 3. Transfer MIJJ in the axial and radial directions within the above gap.
Alternatively, a deformable ring having heat insulation properties is inserted, and the gap is divided into gaps between the pull rod and the ring and between the ring and the sealing pipe, and the fluid resistance in the former gap is reduced by the fluid resistance in the latter gap. 3. A high temperature tensile test device according to claim 1 or 2, characterized in that the fluid resistance is reduced. 4. A plurality of grooves are provided in the axial direction on the outer peripheral surface of the pull rod so that the temperature distribution in the axial and circumferential directions does not vary depending on external conditions, and the grooves are formed in the gap between the pull rod and the confining tube. 4. A high-temperature tensile testing apparatus according to any one of claims 1 to 3, characterized in that convection of 100% is generated steadily within the groove.