JP7611561B2 - Creep test machine and creep test method - Google Patents

Description

The present invention relates to a creep tester that applies a load to a test piece and measures the deformation of the test piece, and a creep test method using this creep tester.

A creep test is known as a test for confirming the lifespan of parts of plants such as thermal power generation facilities and nuclear power generation facilities, and of jet engines and rocket engines, and for measuring the strength of various new materials and composite materials, in which the amount of strain of a test piece under a constant load and the time the load is applied are measured and analyzed (see, for example, Patent Document 1).
In such creep tests, the load is increased or decreased by a fixed amount for each specified strain or time, and the change in load and strain over time is measured. For example, the time until the strain of the test piece reaches a preset first strain is collected as one piece of data, and then the load is increased or decreased by a preset amount and the time until the strain of the test piece reaches a second strain is collected as the next piece of data. This process is repeated to obtain continuous data and perform analysis.

Japanese Patent Application Publication No. 8-43281 Japanese Utility Model Application Publication No. 6-80159 Special Publication No. 2007-510151

In order to obtain highly accurate test results in creep tests in which the load is increased and decreased, the load must be increased and decreased continuously and statically so as not to apply any shock to the test specimen, and the load applied to both sides of the test specimen must be increased and decreased by the same amount and simultaneously.
However, in the creep testing machine described in Patent Document 1, although it is possible to increase or decrease the load by increasing or decreasing the number of pairs of weights 40 that apply a load to the test piece by pulling the test piece from both sides, there is a problem in that it is extremely difficult to increase or decrease the load while satisfying all of the above requirements.

The lever-type constant load testing machine described in Patent Document 2 is provided with a movable weight 3 that can move along the lever 2, and the position of the force point can be changed by moving the movable weight 3 along the lever 2 by turning the threaded rod 4 with the handle 9, and although the load can be increased or decreased statically and continuously, it is difficult to increase or decrease the load applied to both sides of the test piece by the same amount and simultaneously. In addition, the lever-type constant load testing machine described in Patent Document 2 can only increase or decrease the load by an amount corresponding to the weight of the movable weight 3, and there is a problem that the lever-type constant load testing machine becomes large when the length of the lever 2 is long.

Furthermore, in the multi-axis universal testing machine described in Patent Document 3, a motor is used to apply a load to the test piece instead of a weight, and by synchronizing the drive of two paired motors, the load can be increased or decreased simultaneously on both sides of the test piece. However, there is a limit to the magnitude of the load that can be applied by the motor, and a high-output motor is required to perform creep tests on test pieces such as metals, which creates the problem of making the device larger.

The present invention was made in consideration of the above problems, and aims to provide a creep testing machine and creep testing method that can increase and decrease the load continuously and statically in creep tests in which the load is increased and decreased, and that can increase and decrease the load on both sides of the test piece equally and simultaneously, and that can have a simple and compact device configuration.

In order to solve the above problems, a creep testing machine according to claim 1 is a creep testing machine for applying a load to a test piece to measure the deformation of the test piece, the creep testing machine comprising: a lever erected on a base; a first support shaft for attaching the lever to the base so as to be able to swing; a second support shaft provided on the lever at a position spaced apart from the first support shaft and supporting a gripping portion for gripping the test piece; and a third support shaft provided on the lever at a position spaced apart from the first support shaft and the second support shaft and supporting a connecting member connected to a load portion for applying a load to the test piece, at least one of the first support shaft, the second support shaft and the third support shaft being configured as a movable support shaft that can move back and forth in the axial direction of the lever, and a load adjusting unit having a moving means for moving the movable support shaft a preset distance in the axial direction, a pair of the load adjusting units are disposed on both ends of the test piece, and the moving means is configured to have a synchronous moving portion for synchronously moving the movable support shafts of the pair of load adjusting units .

The movable support shaft may be any one of the first support shaft, the second support shaft, and the third support shaft, and two or more support shafts may be movable support shafts, but it is preferable that it be the third support shaft as described in claim 2.
As described in claim 3, the movable support shaft may be configured to be supported by a guide portion formed on the lever and a slider that moves along this guide hole, and the moving means may be configured to include a helical shaft that is screwed into the movable support shaft or the slider, and to move the movable support shaft by rotating the helical shaft.

The moving means may be a manual one, but as described in claim 4, it may be configured to include a driving body such as a servo motor and a control means for controlling the driving of the driving body.
As described in claim 5, the load adjusting unit may further include a load support platform that can be raised and lowered and supports the load portion, and a lifting drive means for synchronously lifting and lowering the pair of load support platforms in the pair of load adjusting units.

The creep test method of the present invention, as described in claim 6, is a method of preparing a creep test machine having a lever erected on a base, a first support shaft that swingably attaches the lever to the base, a second support shaft that is attached to the lever at a position spaced apart from the first support shaft and supports a gripping portion that grips a test piece, and a third support shaft that is attached to the lever at a position spaced apart from the first support shaft and the second support shaft and supports a connecting member connected to a load portion that applies a load to the test piece, at least one of the first support shaft, the second support shaft, and the third support shaft is a movable support shaft that can move back and forth in the axial direction of the lever, and a creep test is performed while changing the load applied to the test piece by moving the movable support shaft.

As a method of performing creep tests by changing the load, the load applied may be changed for each creep test, or the load applied may be changed stepwise or continuously during one creep test. For example, as described in claim 7, after performing a creep test while applying a first load to the test piece, the movable support shafts of the pair of load adjustment units may be moved synchronously to position the test piece at a predetermined position, and a creep test may be performed while applying a second load to the test piece. Alternatively, as described in claim 8, the movable support shafts of the pair of load adjustment units may be moved continuously synchronously to perform a creep test while changing the load applied to the test piece.

As described in claim 9, a load support table that can be raised and lowered and that supports the load portion and a lifting drive means for synchronously raising and lowering the pair of load support tables in the pair of load adjustment units may be provided, and the load applied to the test piece may be temporarily set to zero by synchronously raising and lowering the load support tables during the creep test.

Since the present invention is configured as described above, the load applied to the test piece can be significantly increased or decreased by moving the movable support shaft, and the load can be increased or decreased continuously and statically. Furthermore, since the lever is configured to stand on the base, the two paired load adjustment units can be placed close to each other, making the device configuration compact, and when the load is increased or decreased manually, it is easy to operate the movement means of the two paired load adjustment units simultaneously and by the same amount.

In particular, if a drive such as a servo motor is used as the moving means and the drive is controlled by the control means, the moving means of the pair of load adjustment units can be operated with high precision. Furthermore, by housing such a drive inside the lever, the device configuration does not become large.
Furthermore, according to the present invention, it becomes easy to apply a load to the test piece T while changing the magnitude of the load stepwise during the creep test, and it also becomes possible to carry out a variety of creep tests, such as changing the magnitude of the load continuously during the creep test. It is also possible to temporarily set the load to 0 during the test.

Therefore, the present invention makes it possible to measure the deformation and hardening characteristics of a test piece during stress fluctuations, which could not be measured directly using conventional testing machines and testing methods, and makes it easy to determine the hardening variables to use when mathematically expressing the deformation and creep characteristics of the test piece. Furthermore, by using appropriate hardening variables and hardening models obtained from creep tests, the accuracy of numerical simulations is improved, which makes it possible to more accurately predict deformation during long-term use, thereby contributing to the design of safer equipment and facilities.

Hereinafter, preferred embodiments of the creep testing machine of the present invention will be described with reference to the drawings.
FIG. 1 is a side view illustrating the overall configuration of one embodiment of a creep testing machine of the present invention, FIG. 2 is a plan view of the creep testing machine of FIG. 1, FIG. 3 is an enlarged view illustrating details of a load adjustment unit, where (a) is a side view and (b) is a cross-sectional view taken along line II of (a), FIG. 4 is a partial view showing a modified example of the load adjustment unit of FIG. 3, FIG. 5 is a schematic explanatory diagram of an example of a creep test using the creep testing machine of the present invention, where (a) is a graph showing the relationship between time and load and (b) is a graph showing the relationship between time and strain of a test piece, and FIG. 6 is a diagram illustrating a test piece used in the creep testing machine of this embodiment, where (a) is a plan view and (b) is a cross-sectional view taken along line II-II of (a).

[Test piece]
The test piece T on which the creep test is performed using the creep testing machine 1 of this embodiment has a cross shape as shown in Fig. 8, and its shape is well known as shown in Fig. 4 of Patent Document 1. For example, in order to determine the accurate strength of pressure vessels and pressure piping in power plants and factories, turbine blades of jet engines, etc., the stress-strain characteristics of the material under biaxial stress are required. The cross-shaped test piece T as shown in Fig. 8 is used to determine such stress-strain characteristics under biaxial stress.
The test piece T can be made of steel or super heat-resistant alloy material, but can also be made of damaged material taken from an actual pressure vessel or pressure piping, etc. The test piece T can also be used to determine the stress-strain characteristics of non-ferrous metals, and the test piece T may be made of anisotropic material such as engineering plastics containing reinforcing fibers.

In this embodiment, as shown in FIG. 8, the test piece T has a test piece main body Ta formed in the center, which is the subject of the creep test, and has gripped parts Tb extending in four perpendicular directions from this test piece main body Ta, with the length l of one side being approximately 50 mm and the width s of the gripped parts Tb being approximately 8.4 mm.
The gripped portion Tb is intended to be gripped by the gripping portion 106 (see Figure 3) of the load adjustment unit 10 described later, and this gripped portion Tb has multiple slits Tc formed in parallel to each other so that deformations in the X and Y directions do not restrict each other with respect to the load application direction.

The creep test machine 1 of the present invention is not limited to the cruciform test piece T for which creep tests are performed under biaxial stress as described above, but can also be applied to a straight-line test piece for which creep tests are performed under uniaxial stress. In addition, by increasing the number of load adjustment units 10, the creep test machine 1 of the present invention can also perform creep tests under multiaxial stress using a test piece having, for example, eight gripped parts Tb extending in eight directions from the test piece main body part Ta.

[Overall configuration of creep tester]
As shown in Figures 1 and 2, the creep testing machine 1 of this embodiment has a stand 12 that is placed on or fixed to a horizontal floor surface, a table, etc., a plurality of load adjustment units 10 (four in this embodiment) supported by a base 122 of the stand 12, a weight 128a for applying a load to a test piece T arranged in the center of the plurality of load adjustment units 10, and a wire 126 connecting the load adjustment unit 10 and the weight 128a.
Further, in the center of the load adjustment unit 10, a heating furnace 13 is provided which accommodates the test piece T and heats the test piece T to a preset temperature during the creep test.

[Configuration of the stand]
As shown in FIG. 2, in this embodiment, two pairs of paired load adjustment units 10, i.e., four load adjustment units 10, are arranged on the base 122 of the stand 12 at equal intervals facing each other on the orthogonal X-axis and Y-axis lines.
The stand 12 has a support table 120 that is placed on or fixed to a horizontal floor surface, a table, or the like, and a plurality of legs 121 that stand upright on the support table 120 , and a base 122 is provided on the upper ends of the legs 121 .

The base 122 is formed in a cross shape as shown in FIG. 2, and four load adjustment units 10 are arranged on each of the four protrusions that form the cross. The tip of the protrusion is bent upward to form an arm 123, and a pulley 124 is supported at the upper end of the arm 123 so that it can rotate freely. A wire 126 connected to the load adjustment unit 10 hangs down from the pulley 124, and one or more weights 128a are suspended from the tip of the wire 126 via a rod 127. The rod 127 and weights 128a constitute a load section 128 that applies a load to the test piece T.

In addition, through holes 122a are formed in the base 122 to correspond to the positions of the four load adjustment units 10, and each of the load adjustment units 10 is supported on the base 122 while being inserted into the through holes 122a.

Reference numeral 125 denotes a weight support stand serving as a load support stand for supporting the weight 128a, and is provided with a lift table 125a that can be raised and lowered with the weight 128a placed on it. In the weight support stand 125 of a pair of opposing load adjustment units 10, for example, as shown in FIG. 1, the two lift tables 125a may be connected by a connecting bar 125b, and the two lift tables 125a may be raised and lowered synchronously by one hydraulic jack. In the initial state before the creep test, the two lift tables 125a of the pair of load adjustment units 10 are raised and the weight 128a is placed on them so that no load is applied to the two paired load adjustment units 10. However, when the test piece T is attached to the two load adjustment units 10 and the creep test is started, the hydraulic jack is driven to slowly lower the two lift tables 125a at the same time, so that the same amount of load can be statically applied to both sides of the test piece T at the same time. In addition, by simultaneously raising the two lift tables 125a and placing weights 128a on each of the two lift tables 125a at the same time, the load acting on the test piece T can be set to zero not only at the end of the creep test but also during the creep test.

[Configuration of load adjustment unit]
The load adjustment unit 10 has a lever 100 that is erected on a base 110 fixed to a base 122 by a bolt or the like and is swingable by a first support shaft 108. The lower end side of the lever 100 passes through a through hole 122a of the base 122 and extends below the base 122, and a balancer 112 is attached to one end of the lever 100 for maintaining the lever 100 in a vertical position with the support shaft 108 as a fulcrum in an unloaded state.
A second support shaft 107 is provided above and spaced a distance L2 from the first support shaft 108, parallel to and in the same direction as the first support shaft 108, and a mounting arm 105 extending from the second support shaft 107 toward the other load adjustment unit 10 facing in the horizontal direction is attached to the lever 100 so as to be able to swing freely via the second support shaft 107. A gripping portion 106 is attached to the very tip of the tip of the mounting arm 105 via a connecting pin 106a, and the gripped portion Tb of the test piece T is gripped by the tip of the gripping portion 106.

The mounting arm 105 can be moved back and forth in the axial direction by the handle 105a, and the distance between the gripping parts 106, 106 of the two opposing load adjustment units 10 can be adjusted, making it easier to attach the test piece T and allowing the distance to be adjusted appropriately according to its length.

A third support shaft 109 is provided above and spaced a distance L1 from the second support shaft 107, parallel to and in the same direction as the first support shaft 108 and the second support shaft 107. A connecting member 102 extends horizontally from the third support shaft 109 in the opposite direction to the mounting arm 105, and is attached to the lever 100 via the third support shaft 109 so as to be able to swing freely. A wire connecting hole 102a is formed at the tip of the connecting member 102, and one end of the wire 126 is connected to this wire connecting hole 102a.

An elongated guide hole 103 having a long axis in the up-down direction is formed through the upper part of the lever 100, and a slider 115 that moves up and down along this guide hole 103 is inserted into the guide hole 103. The third support shaft 109 is supported by the slider 115 and can move up and down along the guide hole 103 together with the slider 115 between an upper limit position (i) and a lower limit position (ii) shown in Figure 3. In this embodiment, the third support shaft 109 is a movable support shaft.
An upper end member 104 is attached to the upper end of the lever 100 so as to close the upper open portion of the guide hole 103. A through hole 104a is formed in this upper end member 104, which penetrates to the guide hole 103, and the helical shaft 101 extends into the guide hole 103 by inserting through this through hole 104a.

A shaft head 101a is formed at the upper end of the helical shaft 101, and is located above the upper end member 104. A bearing 101b is provided between the shaft head 101a and the upper end member 104 to rotatably support the shaft head 101a while preventing the helical shaft 101 from falling from the through hole 104a into the guide hole 103. The helical shaft 101 is screwed into a helical hole 109a formed through the center of the third support shaft 109, and by rotating the helical shaft 101 via the shaft head 101a, the third support shaft 109 is raised and lowered along the guide hole 103.

With the above configuration, when a tool such as a wrench or a handle is engaged with the shaft head 101a and the shaft head 101a is rotated in the direction C in the figure, the helical shaft 101 rotates and the third support shaft 109 screwed into the helical shaft 101 moves up and down along the guide hole 103. This allows the distance L1 between the second support shaft 107 and the third support shaft 109 to be changed between long and short.
In addition, it is preferable to provide a scale along the guide hole 103 so that the magnitude of the distance L1 that is changed from long to short can be visually confirmed.

In this embodiment, the helical hole 109a formed in the third support shaft 109 and the helical shaft 101 constitute a moving means P for moving the movable support shaft. Also, in this embodiment, the lever 100, which has the first support shaft 108 as a fulcrum, the second support shaft 107 as a point of application, and the third support shaft 109 as a point of force, amplifies the load of the load section 128 at a ratio according to the distances L1 and L2 by the leverage, and transmits the amplified load to the test piece T.
The load adjustment units 10 having the above configuration are arranged on the base 122 in pairs, one on each end of the test piece T. In this embodiment, two pairs (four) of load adjustment units 10 are arranged on the base 122 so that a creep test can be performed on the cross-shaped test piece T.

[Another embodiment of the load adjustment unit]
FIG. 4 shows another embodiment of the load adjusting unit.
The load adjustment unit 10 in FIG. 3 rotates the helical shaft 101 manually using a tool such as a wrench or a handle. The creep tester 1 of the present invention has a configuration in which the lever 100 is erected, so that two paired load adjustment units 10 can be arranged close to each other. In this embodiment, by using a small test piece T with a side length l of about 50 mm, the distance between the paired load adjustment units 10 can be about 40 cm, and the size of the device and the side length H (see FIG. 2) can be within a range of about 60 cm. Therefore, it is easy for one operator to simultaneously operate the helical shafts 101 of the two load adjustment units 10 with both hands, and it is also easy to make the rotation angles of the helical shafts 101 of the two load adjustment units 10 the same.
However, in order to raise and lower the third support shaft 109 of the two load adjustment units 10 more precisely, it is preferable to rotate the helical shaft 101 using a driving body such as a servo motor.

In the load adjustment unit 10' of the embodiment shown in FIG. 4, the helical shaft 101' is connected to the rotating shaft of a driver M such as a servo motor, and the helical shaft 101' is rotated by driving the driver M. The driving of the driver M can be controlled by a control unit (not shown) provided outside the load adjustment unit 10'. For example, by outputting a command to the driver M to rotate the helical shaft 101' by a preset rotation angle after a preset time has elapsed or after a preset amount of strain has been reached, the third support shaft 109 can be raised and lowered by the same amount in synchronization between the two paired load adjustment units 10'.

In this way, by raising and lowering the third support shaft 109 using a driving body M such as a servo motor, it is possible to synchronize the raising and lowering of the two third support shafts 109 in the paired load adjustment unit 10' with high precision and to precisely match the amount of raising and lowering.
As in the example of Figure 4, by forming a hollow portion inside the lever 100 and accommodating the driver M within the lever 100, the driver M and the helical shaft 101' do not protrude outside the load adjustment unit 10', and the load adjustment unit 10' can be accommodated within the same size (height) as the load adjustment unit 10 of the previous embodiment.

[Explanation of creep test method]
Next, a creep testing method of the present invention using the creep testing machine 1 having the above configuration will be described together with the operation of the creep testing machine 1 having the above configuration.
First, in the initial state before the creep test starts, the lift table 125a of the weight support stand 125 is raised to place the weight 128a thereon so that no load is applied to the paired load adjustment unit 10 (10'). Also, in this initial state, the positions of the third support shafts 109 are aligned by the support shaft moving means P (P') so that the distance L1 between the second support shaft 107 and the third support shaft 109 in the two load adjustment units 10 (10') is the same.
Next, the test piece T shown in FIG. 8 is prepared, and each of the four gripped portions Tb is gripped by the gripping portions 106 of the two pairs of four load adjustment units 10 (10').
After the gripping is completed, when the creep test is started, the lifting tables 125a of the weight supports 125 of the load adjustment units 10 (10') are lowered in synchronization, and loads are applied to the test piece T from four directions simultaneously.

The magnitude of the load F applied to the test piece T is determined by the weight (W) of one or more weights 128a, the distance L2 from the first support shaft 108, which is the fulcrum, to the second support shaft 107, which is the point of application, and the distance L1+L2 from the first support shaft 108 to the third support shaft 109, which is the point of force, and the relationship L2×F=(L1+L2)×W holds. If the ratio of distances L1 and L2 is 9:1 (L1:L2=9:1), a load ten times the weight (W) of one or more weights 128a will be applied to the test piece T.

In this state, after a preset time has elapsed or when a preset strain amount has been reached, the third support shaft 109 is moved by a preset length α. In the creep testing machine 1 of the present invention, it is easy to synchronize the spiral shafts 101 of the two paired load adjustment units 10 and rotate them by the same amount at the same time, and in the load adjustment unit 10' using a driver M such as a servo motor, the driver M can be automatically driven under preset conditions to rotate the spiral shafts 101 of the two load adjustment units 10 synchronously, and it is possible to move the third support shaft 109 by the preset length α with higher accuracy.

If the connecting member 102 is raised by, for example, a length α, so that the distance L1 becomes L1 + α, the above formula becomes L2 × F = ((L1 + α) + L2) × W. If the length of movement α is set to just over 10% of the distance L1 and the ratio of the distance L1 + α to the distance L2 is set to 10:1, the load applied to the test piece T can be increased by approximately the same amount as the weight (W) of one or more weights 128.
FIG. 5 is a graph showing a schematic relationship between stress (load) and time according to the creep test method of this embodiment.
As shown in this graph, by gradually changing the load as time passes from t1, t2, t3, ... and gradually changing (increasing in this graph) the load σ acting on the test piece T, the strain (deformation) of the test piece T at each load σ1, σ2, σ3, ... can be observed.
When the load σ is changed stepwise, the load σ may be temporarily set to 0. In this case, the lifting tables 125a of the paired weight support bases 125 are synchronously raised, and the weight 128a is placed on the lifting tables 125a.

[Another embodiment of the creep test method]
In another embodiment of the creep test method of the present invention, after the creep test is started, the third support shaft 109, which is the movable support shaft, is moved continuously at a constant speed in synchronization with the pair of load adjustment units 10, 10'. The speed may be constant from the start to the end of the creep test or may be variable during the test (including a speed of 0).
FIG. 6 is a graph showing a schematic relationship between stress (load) and time according to the creep test method of this embodiment.
As shown in this graph, the load is changed linearly from the start of the test to time t4, and the load σ acting on the test piece T is changed from σ4 to σ5 (this graph shows the case where the load σ is increased, but it is also possible to decrease the load σ from σ4 to σ5), thereby making it possible to observe the strain (deformation) of the test piece T under a linear change in load.

[Yet another embodiment of the creep test method]
In yet another embodiment of the creep test method of the present invention, after the creep test is started, the third support shaft 109, which is a movable support shaft, is synchronized in the paired load adjustment units 10, 10' to move the load σ so that it changes indefinitely (waveform in the example of FIG. 7) between the maximum value σ8 and the minimum value σ6 from the start of the test to time t5, as shown in the graph of FIG. 7. The minimum load σ6 may be 0, in which case the lift table 125a of the paired weight support stand 125 is lifted in synchronization, and the weight 128a is temporarily placed on the lift table 125a. The speed at which the load σ is changed may be constant from the start to the end of the creep test, or may be variable during the process (including speed 0).

In this way, in the present invention, at least one of the support shafts (the third support shaft 109 in the above embodiment) is made a movable support shaft, and the movable support shaft (the third support shaft 109 in the above embodiment) of the paired load adjustment units 10, 10' is moved synchronously using a driving body M such as a helical shaft or a servo motor, thereby not only achieving a large load increase/decrease effect without making the device configuration complicated and large, but also enabling the load to be increased/decreased synchronously on both sides of the test piece T by the same amount, continuously, and statically. In addition, it becomes easy to apply a load of different magnitude to the test piece T in stages during the creep test, and various creep tests become possible, such as continuously changing the load magnitude during the creep test.

Although the preferred embodiments of the present invention have been described, the present invention is not limited to the above-mentioned embodiments.
For example, in the above explanation, the movable support shaft is described as the third support shaft 109, but in the present invention, it is possible to make the first support shaft 108 or the second support shaft 107 the movable support shaft, and it is also possible to make two or all of these three support shafts the movable support shafts.
In addition, from the lower end side of lever 100, first support shaft 108 which is the fulcrum, second support shaft 107 which is the point of action, and third support shaft 109 which is the point of force are arranged in this order, but the arrangement of the fulcrum, point of force, and point of action is not limited to this as long as a lever action is obtained.

1 is a side view illustrating an embodiment of a creep testing machine of the present invention, showing its overall configuration. FIG. FIG. 2 is a plan view of the creep testing machine of FIG. 1 . 1A and 1B are enlarged views for explaining the details of the load adjusting unit, in which (a) is a side view and (b) is a cross-sectional view taken along the line II of (a). 4 is a partial view showing a modified example of the load adjusting unit of FIG. 3. FIG. 1 is a graph showing a schematic relationship between stress (load) and time according to the creep test method of this embodiment. 1 is a graph showing a schematic relationship between stress (load) and time according to a creep test method of another embodiment. 1 is a graph showing a schematic relationship between stress (load) and time according to a creep test method of yet another embodiment. FIG. 1 is a diagram illustrating a test piece used in the creep testing machine of this embodiment, in which (a) is a plan view and (b) is a cross-sectional view taken along the line II-II of (a).

1 Creep tester 10, 10' Load adjustment unit 100 Lever 101 Spiral shaft 101a Shaft head 102 Connecting member 103 Guide hole 104 Upper end member 104a Through hole 105 Mounting arm 105a Handle 106 Grip portion 106a Connecting pin 107 Second support shaft 108 First support shaft 109 Third support shaft 110 Base 112 Balancer 115 Slider 12 Frame 120 Support base 121 Leg 122 Base 122a Through hole 123 Arm 124 Pulley 125 Weight support base (load support base)
125a Lift table 125b Connecting bar 126 Wire 127 Rod 128 Loading portion 128a Pound 13 Heating furnace

Claims (9)

A creep testing machine that applies a load to a test piece and measures the deformation of the test piece,
A lever provided on a base;
a first support shaft for attaching the lever to the base so as to be able to swing;
a second support shaft provided on the lever at a position spaced apart from the first support shaft and supporting a gripping portion that grips the test piece; and a third support shaft provided on the lever at a position spaced apart from the first support shaft and the second support shaft and supporting a connecting member connected to a load portion that applies a load to the test piece, wherein at least one of the first support shaft, the second support shaft and the third support shaft is configured as a movable support shaft that can move back and forth in the axial direction of the lever , and a moving means is provided for moving the movable support shaft a preset distance in the axial direction;
having
A pair of the load adjustment units are disposed on both ends of the test piece,
the moving means includes a synchronous moving unit that synchronously moves the movable support shafts of the pair of load adjustment units;
A creep testing machine characterized by: The creep testing machine according to claim 1, characterized in that the movable support shaft is the third support shaft. 3. The creep testing machine according to claim 1, wherein the movable support shaft is supported by a guide hole formed in a lever and a slider that moves along the guide hole, and the moving means includes a helical shaft that is screwed into the movable support shaft or the slider, and the movable support shaft is moved by rotation of the helical shaft. A creep tester according to any one of claims 1 to 3, characterized in that the moving means comprises a driving body and a control means for controlling the driving of the driving body. Further comprising a load support platform that can be raised and lowered and supports the load portion, and a lifting and lowering drive means for synchronously raising and lowering the pair of load support platforms in the pair of load adjustment units;
The creep tester according to any one of claims 1 to 4, a first support shaft for attaching the lever to the base in a swingable manner; a second support shaft for supporting a gripping portion for gripping a test piece, the second support shaft for supporting a connecting member connected to a load portion for applying a load to the test piece, the third ...
a pair of the load adjusting units arranged on both ends of the test piece are moved in a synchronized manner to move the movable support shafts, thereby performing a creep test while changing the load applied to the test piece;
A creep test method comprising: 7. The creep testing method according to claim 6, further comprising the steps of: performing a creep test while applying a first load to the test piece; moving the movable support shafts of the pair of load adjustment units in synchronization to position the test piece at a predetermined position; and performing a creep test while applying a second load to the test piece. 7. A creep testing method according to claim 6 , characterized in that the movable support shafts of the pair of load adjustment units are continuously moved in synchronization with each other to perform a creep test while changing the load applied to the test piece. a load support platform capable of being raised and lowered and supporting the load portion; and a lifting and lowering drive means for synchronously raising and lowering the pair of load support platforms in the pair of load adjustment units;
synchronously raising and lowering the load support table during the creep test to temporarily reduce the load applied to the test piece to zero;
The creep test method according to any one of claims 6 to 8 , characterized in that

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