JPS5830532B2 - Cryogenic impact test method and testing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a Charpy or falling weight impact test method for measuring the tenacity of test materials at cryogenic temperatures, and a testing machine used to carry out the method.

Conventionally, the above-mentioned test method involves immersing a test piece in a liquefied gas (e.g. alcohol, Freon, etc.) that is cooled and maintained at a low temperature, holding it for a certain period of time, then quickly taking out the test piece, setting it in a testing machine, and conducting the test. The first method is to surround the test piece with a box made of heat insulating material such as styrofoam or paper.
A known method is to place the entire box in a testing machine, pour low-temperature liquefied gas such as liquid helium into it, and then perform the test in this state.

However, the specific heat of a substance generally decreases as the temperature decreases, and particularly when the temperature drops to the level of low-temperature liquefaction, the specific heat decreases extremely.

For this reason, for example, there is a report that when a test piece of A1 alloy is taken out from liquid helium into air, a temperature rise of 60° C. is observed in 1.5 to 2 seconds.

Therefore, according to the former method mentioned above, since the test piece is exposed to air after being cooled, the temperature rises instantaneously, making the temperature unstable and making it difficult to test at the set low temperature. Measured values also had the drawback of being unreliable.

On the other hand, according to the latter method, the test piece does not need to be taken out into the air, so it can solve the above-mentioned disadvantage of the former method, but it is not only inefficient, but also because the insulation box is destroyed each time the test is carried out. However, it is troublesome and complicated because it is necessary to correct the influence of the heat insulating box on the measured value of strength, and it also has the disadvantage that it is difficult to control the temperature arbitrarily.

Therefore, as a result of studies in view of the above-mentioned conventional drawbacks, the present invention has developed a new cryogenic impact testing method and testing machine. By making it possible to perform tests in the same impact test space with virtually no exposure to the atmosphere, the temperature is stable and highly reliable measurements can be obtained, and the test specimen The purpose of this invention is to avoid the troublesome work of taking out the liquid into the atmosphere and correcting the measured values, thereby improving the work efficiency of impact tests.

Prior to the explanation of the test method which is the first invention of the present application,
The test and test machines of the second to fourth inventions applied to the implementation of the method will be described in detail based on the illustrated specific examples.

As shown in FIGS. 1 and 2, the fuselage 1 is, for example,
Frame 2, which is formed into a horizontally long frame by appropriately framing shaped steel materials, etc.
A shock generating device 3 using a hammer 4 or a falling weight and a heat insulating box 5 are mounted approximately in the center of the top, and a low temperature liquefied gas supply device 6 and driving means 7, 7 are also provided.

In the illustrated example, a hammer 4 is used as the impact generating means, but it is of course possible to use a falling weight as shown in the upper part.

As shown in FIGS. 3 to 5, the impact generating device 3 is constructed by a support 9 for the scissors 8 and a main pillar 10 erected from the support 9. The hammer 4 is rotatably pivoted to the frame 11 by a shaft 12, and the support stand 9 is connected to a shield plate fixed to the main body 5a of the insulation box 5 by a stud shaft 13. 14, and is fixedly housed within the heat insulating box 5, and the impact generating device 3 projects upward from the heat insulating box 5.

The insulation box 5 also includes a main body 5a and left and right movable parts sb.
.
6, and are disposed so as to be movable in the left and right directions, respectively, so that the passage ports 17 and 18 for the hammer 4, which are opened on the left and right sides of the upper part of the main body 5a, can be opened and closed.

Here, the openings 17 and 18 are provided with a size large enough and minimum enough for the hammer 4 to pass through, and the movable parts 5b and 5c have no openings when the respective movable parts 5b and 5c are closed.
The test space 19 having the support stand 9 inside the main body 5a is
A shield plate 23 is provided on the inside via the stud shaft 22 . . . to provide heat insulation together with the shield plates 14, 20, 21 .

The movable parts 5b and 5c are connected to drive means 7 and 7 such as air cylinders mounted on the pedestal 2, and are reciprocated from side to side.
8 to open and close.

Further, the low temperature liquefied gas supply device 6 includes one or more injection nozzles 24.24 that are fixed to the main body 5a of the heat insulation box 5 and spray low temperature liquefied gas onto the test piece 8, and the nozzles 24.24 are attached to the body of the machine. It is constructed by connecting a gas container 25 installed outside with a vacuum-insulated piping 26.

Next, the operation of the first invention of the present application and the second invention configured as described above will be explained.

First, the movable part 5b is moved by the drive means 7,7.

5c (in the illustrated example, the 5b side) is moved back to open the passageway 17, and once the test piece 8 is set on the support stand 9, the movable part 5b is moved to the main body 5a side and the passageway 18 is opened.
Close.

Next, liquid helium or the like is sprayed onto the test piece 8 from the injection nozzle 24, 24 by the low-temperature liquid gas supply device 6, and after the test piece 8 is cooled to a predetermined temperature, the movable part 5 is
b and 5c are moved backward by their respective drive means 7.7 to open the passageways 1γ and 18, and at the same time the hammer 4 is shaken down to collide with the test piece 8, but at this time, the injection of liquid helium is continued. Also, by opening the openings 17 and 18, the test piece 8 is prevented from coming into contact with the atmosphere, thereby preventing the temperature rise of the scissors piece 8.

In this way, the space that supports the test piece 8 and the impact test space are the same, and the insulation box 5 that surrounds that space opens only at the part where the hammer 4 passes through. 18 After opening, apply liquid helium etc. to the test piece 8.
Since the temperature is not increased, the impact test can be carried out at a predetermined temperature.

Also, both rotating parts 5b for opening the above-mentioned openings 17 and 18,
The action of 5c and the action of swinging down the hammer 4 can also be synchronized by any means.

Further, the extra space inside the insulation box 5 may be used to store a test piece next time.In this case, the test piece is pre-cooled, so it is placed on the support stand 9 and tested. This allows cooling to the set temperature in a short time.

Next, in the third invention of the present application, the above-mentioned aircraft body 1 is housed in a case 27 made of, for example, a transparent acrylic plate, and even when an impact test is performed with the entrances 17 and 18 opened as described above, the airframe 1 is kept at a low temperature. The structure is such that liquefied gas does not mix with the atmosphere (air).

As shown in FIG. 1, the case 27 is provided with a recovery pipe 29 with a pulp 28 attached thereto, and when the case 27 is filled with low-temperature liquefied gas.

so that they can be collected and reused.

When the fuselage 1 is housed in the case 27 in this way, mixing of the low-temperature liquefied gas and air is prevented, so a rise in the temperature of the test piece 8 can be more completely prevented. Furthermore, since frost can be prevented from forming on the heat insulating box 5, the cooling efficiency of the test piece 8 can be further improved.

Furthermore, the fourth invention of the present application, as shown in FIGS. 6 and 7, supports the test piece 8' stored in the extra space inside the heat insulating box 5 from outside the case 27. The magic hand 30 is airtightly attached to a part of the case 27 so that it can be placed on the case 9.

In this S, the magic hand 30 has a support rod 32 with a grip part 31, and the support rod 32 holds the grip.

The movable rod 35 is supported so that it can slide freely against the elasticity of the spring 34 by pulling the trigger 33 of the section 31. Slide against the force, clamp the test piece 8' between clamping pieces 32a and 35a provided at the tip of the support rod 32 and the tip of the movable rod 35, respectively, and release the trigger 32. The movable rod 35 is a spring 34
The test piece 8' is released by sliding toward the distal end.

Furthermore, this magic hand 30 is not limited to the above-mentioned configuration, and any other structure may be used. It is airtightly and movably supported.

According to the above configuration, the test pieces 8' are stored in the surplus test space of the heat insulating box 5 and pre-cooled, and placed on the support stand 9 by the magic hand 30 while the machine body 1 is in a sealed state. When setting the test piece,
This is advantageous in that it is possible to prevent air from entering the test space 19 and to minimize the temperature rise of the pre-cooled test piece.

As explained above, according to the cryogenic impact test method according to the present invention, the test piece 8 is set on the support stand 9, and is cooled and
Since the impact test is conducted in that space while controlling the temperature, the test piece 8 is not exposed to the air, so the temperature is stable and the impact test can be performed under the specified low temperature conditions. Therefore, unlike the conventional method of destroying the heat insulating box on the night of the test, there is no need to correct the influence on the measured values, so that highly reliable measurement results can be obtained easily.

Furthermore, according to the testing machine of the present application, the insulation box 5 is designed to open the passage ports 17 and 18 only in areas where the hammer 4 and the falling weight can pass through, in time with the fall of the hammer 4 and the falling weight. Therefore, the structure was designed to minimize the temperature rise of the test piece, and the test piece 8 was not exposed to air by continuing to inject low-temperature liquefied gas during the test, so it was difficult to carry out the above test method. Furthermore, since the fuselage 1 is internally housed in a case 27, and the magic hand 30 is attached to the case 27, the fuselage 1 and its insulation are It is possible to prevent frost from forming on the box 5, the cooling efficiency is good, the low-temperature liquefied gas in the case 27 can be recovered and reused, and the heat insulating box 5 is not destroyed, so it is economical. It's safe.

In order to set the test piece 8 to the desired chill temperature, a temperature sensing element is brought into contact with the test piece 8, and the output from the element is used to control the amount of low-temperature liquefied gas ejected, chill temperature, etc., as appropriate. Means can be used.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a specific example of a testing machine capable of carrying out the cryogenic impact test method according to the present invention, Fig. 2 is a plan view of the machine, and Fig. 3 is an enlarged longitudinal cross-sectional front view of the insulating box of the machine. Figure 4 is an enlarged longitudinal sectional side view of the insulation box, Figure 5 is an enlarged cross-sectional view of the insulation box, Figure 6 is a partial front view showing the state in which the magic hand is attached to the aircraft, and Figure 7 is FIG. 2 is a partial side view showing an example of a magic hand. DESCRIPTION OF SYMBOLS 1... Airframe, 3... Shock generator, 4... Hammer 5... Insulating box, 5a... Main body of the insulating box, sb,
5c... Movable part of the insulation box, 6... Low temperature liquefied gas supply device, 7... Drive means, 8... Test piece, 9...
・・Support stand, 17° 18 ・・Hammer etc. entrance, 19
...Test 1 test space, 24...Injection nozzle, 27...
Case, 30...Magic Hand.

Claims (1)

[Claims] 1. In the Charpy and falling weight impact test methods, the X test space is surrounded by a heat insulating box while the test piece is set on a support stand, and low temperature liquefied gas is sprayed onto the test piece so that the test piece reaches a set temperature. When this happens, only the opening of the hammer or falling weight in the insulation box is opened in synchronization with the impact action of the hammer or falling weight, while continuing to spray low temperature liquefied gas even when the opening is open. A cryogenic impact test method, characterized in that an impact test is performed for the test. 2. An impact generating device such as a hammer or falling weight with a supporting stand for the test piece 1 at the bottom, an insulating box that surrounds the test space with the test piece set on the supporting stand, and the test piece inside the insulating box. and a low-temperature liquefied gas supply device equipped with an injection nozzle for spraying low-temperature liquefied gas to the body, and the heat-insulating box has a movable part relative to the stationary body, and the movable part controls the action of the hammer or falling weight. A cryogenic impact tester, characterized in that it is attached to a desired driving means so that the opening operation is performed in synchronization with the opening operation. 3% In the cryogenic impact test machine described in claim 2, it is possible to prevent mixing of low-temperature liquefied gas and the atmosphere at least during the impact test with the opening of the hammer or falling weight open. A cryogenic impact testing machine characterized by having a body built into a case. 4. In the cryogenic impact tester set forth in claim 2, the fuselage is cased to prevent mixing of the low-temperature liquefied gas with the atmosphere at least during the impact test with the opening for the hammer or falling weight open. A magic hand is airtightly attached to the case so that the test piece for the next test to be placed in the remaining space of the test space can be set on the support stand by operation from outside the case. A cryogenic impact tester featuring: