JPH07209160A - Impact testing machine - Google Patents

Abstract

PURPOSE:To provide a reliable impact testing machine which can easily perform a impact test in an environment where temperature, atmosphere, pressure, etc., are set to special conditions. CONSTITUTION:The machine for measuring the fracture energy of a test piece 5 is provided with impact piece retention mechanism 3 and 4 for freely dropping a percussion piece 1 from the retained state, a test piece retention mechanism 6 for horizontally retaining the test piece 5 at a specific position where the freely falling percussion piece 1 passes, a speed measurement mechanism 7 for measuring the falling speed of the percussion piece 1, and an environmental setting mechanism 10 for setting the environment such as the temperature, atmosphere, and pressure at a part for retaining the test piece 5 in a specific state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact tester for measuring the breaking energy of a test piece, and particularly to temperature, atmosphere,
The present invention relates to an impact tester suitable for an impact test in an environment where atmospheric pressure and the like are set in a special state.

[0002]

2. Description of the Related Art Conventionally, Charpy impact testers and Izod impact testers have been widely used as impact testers. These impact testers swing down a pendulum-shaped impact piece from a specified angle, break the test piece, and then measure the angle of the impact piece that has been swung up by inertia, and the initial angle and inertia of the impact piece are measured. This is a device to determine the energy absorbed by the impact destruction of the test piece from the difference in the angle of swinging up.

By the way, when it is desired to perform an impact test in an environment in which the temperature, atmosphere, atmospheric pressure, etc. are set to special conditions,
It is often difficult to perform an impact test by installing the Charpy impact tester or the Izod impact tester in such an environment, and therefore, for example,
When performing an impact test at high temperature, remove the test piece heated in the heating furnace from the heating furnace and quickly set it in the test machine,
The method of conducting an impact test is adopted. In this case, the temperature of the test piece at break cannot be directly measured, and the temperature of the test piece is an estimated value. It was difficult to carry out the test while keeping the conditions constant.

As a method of measuring impact force other than the above impact tester, a transducer such as a strain gauge is attached to a hitting piece or a test piece, the test piece is hit with the hitting piece, and the obtained data is used as the impact force. -There is a method of processing by numerical calculation using the relation of distortion. As a method of measuring the high temperature impact fracture toughness using this method, a method is proposed in which a test piece is hung and held by a ceramic thread in a heating furnace, and the test piece is hit with a free-falling hitting piece. ing. In this method, a part of the hitting piece is extended to the outside of the heating furnace, and a strain gauge is attached to this part to measure the impact force.

By the way, in the method using the transducer such as the strain gauge, it is necessary to obtain the relationship between the impact force and the strain in advance. However, since this relationship is derived based on the measurement result by the static load, this relationship is impacted. When applied to a dynamic measurement such as a test, it is easy to include an error,
There was a problem that the reliability of the impact test was low. In addition, the derivation of the impact value requires a complicated numerical calculation, which takes time. Also, when the strain gauge attachment position (detection position) is far from the impact position, as in the case of measuring high temperature impact fracture toughness, it is easy to include an error in the process of the shock wave propagating through the impact piece, and the impact test Had a problem of low reliability.

[0006]

In view of the problems of the above-described conventional impact tester or impact test method, the present invention simply performs an impact test in an environment in which the temperature, atmosphere, atmospheric pressure, etc. are set to special conditions. It is an object of the present invention to provide an impact tester capable of performing and having high reliability.

[0007]

In order to achieve the above object, an impact tester according to the first aspect of the present invention comprises an impact piece holding mechanism for freely dropping an impact piece from a holding state, and an impact piece for freely dropping the test piece. The gist of the present invention is that the test piece holding mechanism holds the test piece horizontally at a predetermined position through which the ball passes, and the speed measuring mechanism measures the falling speed of the impact piece.

Further, the impact tester of the second aspect of the present invention is the impact tester of the first aspect of the present invention, which has an environment setting mechanism for setting the environment such as temperature, atmosphere and atmospheric pressure of the place where the test piece is held to a predetermined state. That is the summary. In this case,
Objects set by the environment setting mechanism include temperatures such as ultra-high temperature and ultra-low temperature, atmospheres such as corrosive gas, atmospheric pressure such as high pressure and vacuum, humidity and the like.

[0009]

The impact tester of the present invention smashes a test piece by hitting the test piece with a free-falling hitting piece, and hits the test piece with the velocity (Vj) of the hitting piece when the test piece is not hit. In this case, the energy required to break the test piece, that is, the breaking energy (Ejs) of the test piece is measured from the velocity (Vs) of the impact piece in this case. That is,

[Equation 1] Therefore, the breaking energy (Ejs) of the test piece can be directly measured by measuring the falling speed of the impact piece by the speed measuring mechanism, and the measurement error can be made extremely small by increasing the measurement accuracy of the falling speed. be able to.

Further, by setting the environment such as the temperature, atmosphere and atmospheric pressure of the place where the test piece is held by the environment setting mechanism to a predetermined state, it is possible to carry out the test while keeping various conditions of the impact test constant. .

[0011]

EXAMPLES The present invention will be described below based on examples.

FIG. 1 shows a front sectional view of the impact tester of the first embodiment, and FIG. 2 shows a system block diagram of the impact tester.
The impact tester includes impact piece holding mechanisms 3 and 4 for freely dropping the hitting piece 1 from a holding state, and a test piece holding mechanism 6 for horizontally holding the test piece 5 at a predetermined position where the freely falling hitting piece 1 passes. And a speed measuring mechanism 7 for measuring the falling speed of the striking piece 1 composed of a photoelectric switch.

Impact piece holding mechanisms 3 and 4 in this embodiment
Holds the striking piece 1 by engaging the tip of a stopper 3 slidably supported by a stopper guide 4 with a notch formed in the striking piece 1, and slides the stopper 3 along the stopper guide 4. By moving the striking piece 1, the engagement with the notch formed in the striking piece 1 is released, and the striking piece 1 is allowed to fall freely from the holding state. However, a mechanism having the same action can be adopted. In this case, it is desirable that a striking piece guide 2 is provided around the striking piece 1 so that the striking piece 1 can freely fall vertically, and the striking piece 1 can freely fall in this.

The test piece 5 is moved by the test piece holding mechanism 6.
At a predetermined position where the free-falling hitting piece 1 passes, horizontally,
Holds down and forwards and backwards.

The speed measuring mechanism 7 includes a photoelectric switch,
Any mechanism capable of measuring the falling speed of the hitting piece 1 can be adopted.

In this impact tester, first, when the test piece is not hit, that is, the test piece is not installed, the hitting piece 1 is used.
Is allowed to fall freely, and the time (Tj) required for the striking piece 1 to pass between the upper photoelectric switch 7a and the lower photoelectric switch 7b is measured by sampling at 200 KHz. Upper photoelectric switch 7a and lower photoelectric switch 7
The average passing speed (Vj) is obtained from the distance (H) from b and the measured passing time (Tj).

[Equation 2] The average energy (Ej) is obtained from the average passing speed (Vj) obtained here and the mass (M) of the hitting piece 1.

[Equation 3] Next, when hitting the test piece, that is, by installing the test piece, the hitting piece 1 is allowed to fall freely as in the case described above, and the hitting piece 1 moves the upper photoelectric switch 7a and the lower photoelectric switch 7b.
200KH for the time (Ts) required to pass between
It is measured by sampling at z. The average passage speed (Vs) is obtained from the distance (H) between the upper photoelectric switch 7a and the lower photoelectric switch 7b and the measured passage time (Ts).

[Equation 4] The average energy (Es) is obtained from the average passing speed (Vs) obtained here and the mass (M) of the hitting piece 1.

[Equation 5] From the average energy (Ej) when the test piece is not hit and the average energy (Es) when the test piece is hit,
The energy required to break the test piece, that is, the breaking energy (Ejs) of the test piece is obtained.

[Equation 6] The breaking energy (Ejs) of the test piece obtained here is a value in consideration of energy loss (noise) such as friction between the hitting piece 1 and the hitting piece guide 2. Further, the Charpy value (S) can be derived by dividing the breaking energy (Ejs) of the test piece by the breaking area D of the test piece 5.

[Equation 7] All the above measurements and calculations are done by computer,
Output the calculation result. Thereby, the result of the impact test can be obtained in almost real time.

In Tables 1 and 2, the impact piece 1 has a mass of 3
Using 2.84 g of rod-shaped body (tungsten), test piece 5
Using graphite with a notch as shown in FIG.
The results of an impact test at room temperature are shown below. Here, Table 1 shows
A comparison between the measured value and the theoretical value when the test piece is not hit is shown, and Table 2 shows the breaking energy (Ejs) of the test piece and its Charpy value (S).

[Table 1]

[Table 2]

Next, FIG. 4 is a front sectional view of the impact tester of the second embodiment, and FIG. 5 is a system block diagram of the impact tester. The impact tester includes impact piece holding mechanisms 3 and 4 for freely dropping the impact piece 1 from a holding state, an impact piece guide 2 for guiding the impact piece 1 so as to vertically free fall, and a test piece 5 for free fall. The impact piece 1 has a test piece holding mechanism 6 that horizontally holds the impact piece 1 at a predetermined position through which the impact piece 1 passes, but in addition to that, the impact piece 1 including a laser displacement sensor falls. It is composed of a speed measuring mechanism 7 for measuring the speed and an environment setting mechanism 10 composed of a heating furnace.

The environment setting mechanism 10 comprising a heating furnace in this embodiment has a heater 8 and a heat insulating material 9 and the like.
For example, the temperature can be maintained at an arbitrary temperature of 0 to 2400 degrees Celsius, and the pressure in the furnace can be set from vacuum to pressurization by connecting the inside of the furnace to a pump (not shown). is there. As the environment setting mechanism, in addition to the heating furnace,
It is possible to provide an arbitrary mechanism for setting the environment such as the temperature (ultra-high temperature, ultra-low temperature, etc.) where the test piece is held, atmosphere (corrosive gas, etc.), atmospheric pressure (high pressure, vacuum, etc.), humidity etc. .

In this impact tester, first, when the test piece is not hit, that is, the test piece is not installed, the hitting piece 1 is used.
And drop the test piece 5 with the laser displacement sensor 7.
200 kHz from the upper surface position (point A) of the test piece 5 to the lower surface position (point B) of the test piece 5 by 10 mm.
Measure by sampling at. Then, the speed (Vj) at an arbitrary point between the points B and C is obtained,
Energy (Ej) is calculated by the equation (3). Next, when the test piece is hit, that is, the test piece is installed, the hitting piece 1 is allowed to fall freely, and the laser displacement sensor 7 is used to move the test piece 5 from the upper surface position (point A). 10 mm below the lower surface of the test piece 5 (point B) (point C)
The displacement is measured by sampling at 200 KHz. Then, the velocity (Vs) at an arbitrary point between the points B and C is obtained, and the energy (E
s) is calculated. Then, the energy required to break the test piece, that is, the breaking energy (Ejs) of the test piece is obtained by the equation (6), and the Charpy value (S) is obtained by the equation (7). Also in this embodiment, as in the first embodiment, all the measurement and calculation are performed by the computer, and the calculation result is output. Thereby, the result of the impact test can be obtained in almost real time.

In Tables 3 and 4, the impact piece 1 has a mass of 8
Using a rod-shaped body (tungsten) of 5.55 g, a test piece 5
Using graphite with a notch as shown in FIG.
The results of an impact test at room temperature are shown below. Here, Table 3 shows
A comparison between the measured value and the theoretical value when the test piece is not hit is shown, and Table 4 shows the breaking energy (Ejs) of the test piece and its Charpy value (S).

[Table 3]

[Table 4]

6 and 7 show an example of time-displacement characteristics of the impact piece 1 measured by the laser displacement sensor 7. 7 shows the time-displacement characteristic (enlarged view of FIG. 6) at the moment when the striking piece 1 strikes the test piece 5. This makes it possible to measure how the hitting piece 1 hits the test piece 5 and breaks, and it is possible to obtain data useful for analysis of the mechanism.

As is clear from the comparison between the measured value and the theoretical value when the test pieces shown in Tables 1 and 3 are not hit, the error of the measured value is about 1%, which is a problem for this type of impact tester. It is considered that there is no level. Further, the Charpy value (S) of the graphite used in the above test measured by the Charpy impact tester is

[Equation 8] As is clear from the comparison between this and the Charpy values (S) of the test pieces shown in Tables 2 and 4, it can be said that the impact tester of the present invention is sufficiently suitable for practical use.

[0024]

According to the impact tester of the present invention, the impact test can be performed accurately and easily. Also, by setting the environment such as temperature, atmosphere, atmospheric pressure, etc. of the place where the test piece is held by the environment setting mechanism, it is possible to hold the various conditions of the shock test constant and perform the test. Can be performed more accurately and easily.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an example of an impact tester of the present invention.

FIG. 2 is a diagram showing a system block diagram of the impact tester of FIG.

FIG. 3 is a view showing an example of a test piece.

FIG. 4 is a front sectional view showing an example of the impact tester of the present invention.

5 is a diagram showing a system block diagram of the impact tester of FIG.

FIG. 6 is a view showing a time-displacement characteristic of a hitting piece.

FIG. 7 is an enlarged view of FIG.

[Explanation of symbols]

 1 Striking piece 2 Striking piece guide 3 Impact piece holding mechanism (stopper) 4 Impact piece holding mechanism (stopper guide) 5 Test piece 6 Test piece holding mechanism 7 Speed measuring mechanism (photoelectric switch, laser displacement sensor) 8 Heater 9 Heat insulating material 10 Environment setting mechanism (heating furnace)

Claims (2)

[Claims] 1. An impact tester for measuring the breaking energy of a test piece, comprising: an impact piece holding mechanism for freely dropping the impact piece from a holding state; and a test piece at a predetermined position through which the freely falling impact piece passes. A test piece holding mechanism that holds it horizontally,
An impact tester comprising a speed measuring mechanism for measuring the falling speed of a hitting piece. 2. The temperature, atmosphere, and the like of the place where the test piece is held,
The impact tester according to claim 1, further comprising an environment setting mechanism for setting an environment such as atmospheric pressure to a predetermined state.