JP4326485B2 - Material strength test apparatus and material strength test method - Google Patents

Description

  The present invention relates to a material strength test apparatus and a material strength test method.

  In general, when stress is applied to a metal material placed in a corrosive environment, the metal material cracks under milder conditions than when only corrosion or only stress acts. Stress corrosion cracking (hereinafter referred to as SCC) is known.

The above-mentioned SCC is known to occur due to local loss of protection of the oxide film on the surface of the material, and its generation mechanism varies depending on the corrosive environment and parameters such as stress acting on the metal material or metal material. It is known to be classified into various forms.
Since all of these SCC generation mechanisms have not been clarified, it is theoretically difficult to predict the occurrence of SCC. Therefore, a test is performed in a state close to the environment in which the metal material is used, and an SCC occurrence probability is predicted based on the test result (see, for example, Patent Documents 1 and 2).
Japanese Utility Model Publication No. 6-28707 JP 2003-28787 A Japanese Patent Laid-Open No. 5-297181

In the above-mentioned Patent Document 1, a test piece in which a notch is formed and a motor are coupled via a slider and a torsion bar, and the motor rotates the torsion bar, whereby the test piece is attached to the test piece. A technique for applying a force to open and close the notch is disclosed.
According to this technique, a stress that changes with time can be applied to the test piece, and SCC caused by repeated stress can be evaluated.

  However, with the technique disclosed in Patent Document 1, only one test piece can be evaluated at a time in one test apparatus. Therefore, when many test pieces are evaluated or when evaluation is performed under a plurality of conditions, there is a problem that a long time is required because the number of usable test apparatuses is limited.

In the above-mentioned Patent Document 2, a plurality of capsules are housed in a pressure vessel, and a plurality of test pieces are housed in a stressed state in the capsule, and a highly corrosive solution is circulated in the capsules. Techniques for making them disclosed are disclosed.
According to this technique, since one test apparatus can evaluate a plurality of test pieces at the same condition at the same time, evaluation data of many test pieces can be acquired in a short time.

  However, in the technique disclosed in Patent Document 2, since accurate stress when an SCC is generated on a test piece and an accurate time required until the SCC is generated are unknown, an accurate evaluation is performed. It was difficult.

In the above-mentioned Patent Document 3, a test piece for a tensile test is fixed to a fixing jig and arranged in series, and a load cylinder for applying a tensile load to the series of test pieces is provided, and an operating displacement for detecting the displacement of the load cylinder. A test device with a meter is disclosed.
According to this test apparatus, since one test apparatus can evaluate a plurality of test pieces at the same condition at the same time, many test pieces of evaluation data can be acquired in a short time. .
However, the technique disclosed in Patent Document 3 has a problem that the exact stress when SCC occurs in the test piece is unknown. In addition, there is a problem that it is difficult to specify a test piece in which SCC has occurred from a plurality of test pieces only with the configuration of this test apparatus.

Furthermore, in the above-mentioned Patent Document 3, U-shaped test pieces are arranged in series on a load support cylinder, and a load screw is provided for bending a series of test pieces with a load screw, and a strain gauge is provided on each test piece. A mounting test apparatus is disclosed.
According to this test apparatus, since one test apparatus can evaluate a plurality of test pieces at the same condition at the same time, many test pieces of evaluation data can be acquired in a short time. .
However, the technique disclosed in Patent Document 3 has a problem that the exact stress when SCC occurs in the test piece is unknown.

  The present invention has been made to solve the above-described problem, and is a material strength test apparatus capable of simultaneously testing a plurality of test pieces and acquiring accurate data for each test piece. An object is to provide a material strength test method.

In order to achieve the above object, the present invention provides the following means.
The present invention provides a plurality of holding portions arranged on a predetermined straight line, and a plurality of fixed portions that are movable in a direction along the predetermined straight line and extend in a direction substantially orthogonal to the predetermined straight line. And a test piece disposed between the holding part and the fixing part or between the plurality of fixing parts and fixed to the adjacent holding part or the fixing part , the holding part and the A load is applied to the fixed portion in a direction along the predetermined straight line to apply a tensile stress or a compressive stress to the test piece, and the displacement of each fixed portion in the direction along the predetermined straight line At least one of a displacement measuring unit for measuring the load, a load measuring unit for measuring a load applied by the load loading unit, and the holding unit adjacent to the test piece, and a direction intersecting the predetermined straight line and the fixing Nearly perpendicular to the part Providing material strength testing apparatus, characterized in that has a joint rotatable, to at least one axis of rotation extending.

According to the present invention, by placing a test piece between a plurality of holding parts arranged on a predetermined straight line, and fixing the test piece to an adjacent holding part, the same load is simultaneously applied to the plurality of test pieces, Tensile stress or compressive stress can be applied.
By measuring the displacement of each holding part in a direction along a predetermined straight line in the displacement measuring part, it is possible to obtain information relating to the deformation of each of the plurality of test pieces. Moreover, the information which concerns on the load added to each of a some test piece can be obtained by measuring the load loaded by the load load part in the load measurement part.

By providing the Takashi Seki portions, it can be prevented rotation moment acts on specimens, only the tensile load or compressive load can be loaded. As a result, the test piece can be more accurately evaluated.
In addition, for example, when the holding portion is movably disposed inside the cylindrical member, the holding portion can be prevented from being pressed against the inner peripheral surface of the cylindrical member by providing the joint portion. Therefore, frictional resistance can be prevented from acting between the holding portion and the cylindrical member, and the load acting on the test piece can be prevented from being reduced.

Furthermore, in the above-described invention, it is desirable that the displacement measuring unit is a laser displacement meter, and the holding unit is provided with a reflecting unit that reflects the laser emitted from the laser displacement meter.
According to the present invention, it is possible to obtain information related to the deformation of the test piece by measuring the change in the distance from the laser displacement meter to the reflecting portion using the laser displacement meter.
Since the laser displacement meter is a non-contact measuring device using laser light, it is possible to obtain information relating to the deformation of the test piece without affecting the load acting on the test piece.
For example, in the case of a contact-type measuring device, the load acting on the test piece is reduced due to frictional resistance in the measuring device and the load becomes inaccurate. No problem occurs.
It should be noted that the information related to the deformation of the test piece may be obtained using the above-described contact-type measuring device, but in such a case, obtaining accurate information related to the deformation of the test piece by friction in the measuring device Have difficulty.

  Further, the measurement object of the laser displacement meter that is the displacement measuring unit may be all the holding units that are displaced in a direction along a predetermined straight line, or the holding unit to which a load is first applied from the load loading unit, Instead of directly measuring the displacement of the holding portion, the displacement of the movable portion (for example, the piston portion) in the load load portion may be measured, and is not particularly limited.

In the above invention, it is desirable that at least one of the holding part and the test piece is provided with a fixing means for fixing the test piece to the holding part or the fixing part .
According to the present invention, since the test piece is fixed to the holding portion by the fixing means, even if the test piece is deformed, it can be kept fixed at the same location on the holding portion. Therefore, a plurality of test pieces can be continuously arranged on the predetermined straight line, and an accurate load can be continuously applied to the test pieces.

In the said invention, it is desirable for the said load load part to be equipped with the shaft body which transmits a load to the said holding | maintenance part, and for the said load measurement part to be arrange | positioned at the said shaft body.
According to the present invention, by placing the load measuring unit on the shaft body, for example, it is possible to more accurately measure the load applied to the test piece compared to the case where the load measuring unit is arranged on the load loading unit. it can. That is, by disposing the load measuring unit on the shaft body, it is possible to eliminate the influence of load reduction due to frictional resistance or the like in the load loading unit, and it is possible to measure an accurate load applied to the test piece.

In the above-described invention, it is desirable to include a housing that houses the plurality of holding portions and the test piece, and a corrosive medium supply unit that supplies a corrosive medium in the housing.
According to the present invention, a test piece or the like is housed in a housing, and a stress is applied to the test piece in a corrosive environment by supplying a corrosive medium, and a stress corrosion cracking test is performed on the test piece. be able to.
The corrosive medium may be any of liquid, gas, and mixed medium of liquid and gas, and is not particularly limited.

In the above invention, the test piece is formed in a substantially O-shaped or substantially C-shaped cylindrical shape, and the load is applied along a direction intersecting the central axis of the test piece. desirable.
According to the present invention, by using a test piece having a substantially O-shaped or substantially C-shaped cross section, a load is applied along a direction intersecting the central axis, for example, Compared to the case of using a cylindrical or strip-shaped test piece, since the test piece is not necked in the plastic deformation region, it is easy to perform an evaluation with a large stress applied to the test piece.

The present invention is a material strength test method using the material strength test apparatus of the present invention , wherein a predetermined load is applied to each of the test pieces by the load load section, and the predetermined load is measured by the load measurement section. And measuring the displacement of each holding part by measuring the displacement of each holding part, and measuring the time until the displacement amount of each test piece reaches a predetermined value. A material strength test method is provided.

According to the present invention, a test piece can be arranged between a plurality of holding portions arranged on a predetermined straight line, and a plurality of test pieces can be simultaneously loaded with tensile stress or compressive stress. The strength test can be performed simultaneously.
By measuring the load applied by the load load unit in the load measurement unit, information on the load applied to each of the plurality of test pieces can be obtained.
By measuring the displacement of each holding part in a direction along a predetermined straight line in the displacement measuring unit, it is possible to obtain information related to the deformation of each of the plurality of test pieces, and the displacement amount of each test piece becomes a predetermined value. The time to reach can be measured accurately.

  According to the material strength test apparatus of the present invention, a test piece is disposed between a plurality of holding portions arranged on a predetermined straight line, and the test piece is fixed to an adjacent holding portion, thereby simultaneously being applied to the plurality of test pieces. Since a tensile stress or a compressive stress can be applied, an effect that a plurality of test pieces can be tested simultaneously is obtained.

  By measuring the displacement of each holding part in a direction along a predetermined straight line in the displacement measuring part, it is possible to obtain information relating to the deformation of each of the plurality of test pieces. Further, by measuring the load applied by the load load unit in the load measuring unit, it is possible to obtain information on the load applied to each of the plurality of test pieces, and therefore it is possible to obtain data for each test piece. There is an effect.

  According to the material strength test method of the present invention, it is possible to obtain information related to the load applied to each of the plurality of test pieces by measuring the load applied by the load application unit in the load measurement unit. In addition, by measuring the displacement of each holding part in a direction along a predetermined straight line in the displacement measuring unit, it is possible to obtain information related to the deformation of each of the plurality of test pieces, and the amount of displacement of each test piece is predetermined. Since the time until the value is reached can be accurately measured, the data for each test piece can be obtained.

[First Embodiment]
Hereinafter, a first embodiment of a constant load stress corrosion cracking test apparatus (hereinafter referred to as a constant load SCC test apparatus) according to the present invention will be described with reference to FIG. 1 and FIG.
FIG. 1 is a system diagram showing an overall configuration of a constant load SCC test apparatus in the present embodiment.
In the present embodiment, the constant load SCC test apparatus is a pressurized water reactor (hereinafter referred to as PWR) irradiation induced stress corrosion cracking (Irradiation Assisted) of a member in contact with primary cooling water such as a nuclear reactor.
Stress Corrosion Cracking: hereinafter referred to as IASCC. This will be described by applying to a test apparatus for performing the evaluation according to (1).

As shown in FIG. 1, a constant load SCC test apparatus (material strength test apparatus) 1 includes a stress load section 3 that applies a constant stress to a test piece, and an environment maintenance section that maintains the environment of the test piece in a constant corrosive environment. 5 schematically.
The environment maintaining unit 5 includes a test water tank (corrosive medium supply means) 7 that stores test water (corrosive medium) that simulates the primary cooling water of the PWR, and a stress load unit that supplies test water from the test water tank 7. And a high-pressure metering pump (corrosive medium supply means) 9 that sends out the pressure after being pressurized to 3. The high-pressure metering pump 9 desirably has a performance capable of simulating an environment in which the primary cooling water of the PWR circulates.

  In the present embodiment, description will be made by applying to a configuration including five stress load units 3 and three high-pressure metering pumps 9. In this embodiment, the test water flowing out from the test water tank 7 branches into the high pressure metering pump 9 arranged in parallel, and the test water sent out from the high pressure metering pump 9 is one or two, respectively. It is comprised so that it may flow in into the stress load part 3 of a stand.

Between the high-pressure low-pressure pump 9 and the stress load part 3, a regenerative heat exchanger 11 that uses the high-temperature test water flowing out from the stress load part 3 to raise the temperature of the test water flowing into the stress load part 3 from now on, A preheater 13 for further raising the temperature of the test water heated by the regenerative heat exchanger 11 is disposed. It is desirable that the regenerative heat exchanger 11 and the preheater 13 have an ability to simulate the primary cooling water of the PWR by combining these two.
Further, a high-pressure disk filter 15 is disposed between the high-pressure metering pump 9 and the regenerative heat exchanger 11 and between the regenerative heat exchanger 11 and the test water tank 7, and foreign matters contained in the test water, etc. Has been removed.

The test water tank 7 is provided with a test water measuring unit 17, a hydrogen cylinder 19, and an argon cylinder 21.
The test water measuring unit 17 includes a conductivity meter 23 that measures the conductivity of the test water, a dissolved oxygen meter 25 that measures the dissolved oxygen of the test water, a dissolved hydrogen meter 27 that measures the hydrogen dissolved in the test water, A measuring pump 29 that circulates test water through these measuring meters is schematically configured. These measuring devices measure whether the test water in the test water tank 7 is maintained in substantially the same water quality as the primary cooling water of the PWR.

  The hydrogen cylinder 19 and the argon cylinder 21 are arranged so that hydrogen and argon can be introduced into the test water in the test water tank 7. Thus, since hydrogen and argon can be introduced into the test water, the quality of the test water can be kept substantially the same as the primary cooling water of the PWR.

FIG. 2 is a schematic diagram illustrating the configuration of the stress load portion of FIG.
As shown in FIG. 2, the stress load unit 3 is connected to the test piece holder 33 that holds the test piece 31, the test container (housing) 35 that houses the test piece holder 33, and the test piece holder 33. The load load section 37 applies a compressive load to the test piece 31 and the displacement measurement section 39 measures the breakage of the test piece 31 and the like.

The test container 35 is composed of a container main body 41 and a lid 43 in which a recess is formed. By combining the container main body 41 and the lid 43, a watertight container is formed. The test container 35 is disposed such that the container body 41 is on the upper side and the lid 43 is on the lower side.
A temperature sensor 45 that measures the temperature of the test water is disposed in the recess of the container body 41, and the temperature sensor 45 is connected to a temperature control device 47 that controls the preheater 13 and the like, and the temperature sensor 45 is connected to the temperature control device 47. The temperature information of the test water acquired by 45 is output.
The lid 43 has an inflow pipe (corrosive medium supply means) 49 into which the test water sent from the test water tank 7 (see FIG. 1) flows, and an outflow from which the test water flows out toward the test water tank 7. A pipe line (corrosive medium supply means) 51 is arranged. The open end of the inflow conduit 49 is disposed in the vicinity of the lid 43, and the open end of the outflow conduit 51 is disposed near the bottom surface of the recess of the container body 41.

The test piece holder 33 includes a holder main body (holding portion) 53 and a first holding portion 55 that hold the upper test piece 31A, a second holding portion 57 that holds the middle test piece 31B together with the first holding portion 55, and a second holding portion. A third holding unit 59 that holds the lower test piece 31 </ b> C together with the holding unit 57 is schematically configured.
The upper stage test piece 31A, the middle stage test piece 31B, and the lower stage test piece 31C are all formed of the same metal material, and are formed in a substantially cylindrical shape having a C-shaped cross section. Examples of the metal material include neutron irradiated austenitic stainless steel, but the metal material is not particularly limited to this metal material. Further, the upper test piece 31A, the middle test piece 31B, and the lower test piece 31C may be the same shape test pieces made of the same material, or these test pieces may be made of different materials. These may be formed in different shapes and are not particularly limited.

  When each test piece 31A, 31B, 31C is made of the same material and the same shape, the time until stress corrosion cracking occurs in each test piece 31A, 31B, 31C is measured in one test, and three measurements are made. It is possible to obtain an average time until the stress corrosion cracking determined from the value occurs.

Further, a plurality of test pieces made of different materials / materials may be used for one test, or a plurality of test pieces having different thicknesses and lengths may be used for one test.
Even when the same load is applied, if the thickness and length of the test piece are different, the stress generated in the region where the crack occurs in the test piece is different. Therefore, a test in the case where a plurality of predetermined stresses can be performed by subjecting a plurality of test pieces having different thicknesses and lengths to one test.
As a method of changing the thickness of the above-mentioned test piece, a method of changing the outer diameter of the substantially cylindrical test piece, a method of changing the inner diameter of the test piece, and changing both the outer diameter and the inner diameter. A method can be illustrated. As a method of changing the length of the test piece, a method of changing the dimension in the direction along the central axis of the test piece formed in a substantially cylindrical shape can be exemplified.

The holder main body 53 is formed so as to have a hollow structure having a space therein, and a pull rod described later is connected to one end thereof. Inside the holder main body 53, an upper test piece 31A, a first holding part 55, a middle test piece 31B, a second holding part 57, a lower test piece 31C, and a third holding part 59 are arranged in this order from the top. It is arranged so as to be aligned on a straight line C.
The holder main body 53 and the upper test piece 31A are fixed by a fixing pin (fixing means) 61 disposed on the central axis C. Similarly, the upper stage test piece 31A and the first holding part 55, the first holding part 55 and the middle stage test piece 31B, the middle stage test piece 31B and the second holding part 57, the second holding part 57 and the lower stage test piece 31C, and the lower stage test piece. 31C and the 3rd holding | maintenance part 59 are being fixed by the pin 61 for fixing.

The first holding part 55 and the second holding part 57 are formed with a laser reflecting part (reflecting part) 63 extending toward the outside of the holder main body 53. The first holding part 55 and the second holding part 57 are arranged so that the respective laser reflecting parts 63 are not located in the same region when viewed from the axial direction of the central axis C.
The third holding portion 59 is fixed to the lid 43 and is disposed so as not to contact the holder main body 53.

The load load portion 37 is generally configured by an air cylinder portion 65 that generates a load load and a pull rod (shaft body) 67 that transmits the load load generated by the air cylinder portion 65 to the test piece holder 33.
The air cylinder portion 65 includes a cylinder portion 69 and a piston portion 71, and a compressed air supply passage 72 to which compressed air for generating a load load is supplied from the outside is connected to the cylinder portion 69. The piston portion 71 is connected to the pull rod 67 and is configured to be pushed downward (downward in FIG. 2) together with the pull rod 67 by compressed air supplied to the cylinder portion 69.

The pull rod 67 is provided with a load cell 73 for load measurement and a cooling water channel 75 for cooling the pull rod 67 in this order from the air cylinder 65 side.
By providing the load cell 73 in the pull rod 67, it is possible to accurately measure the load applied to the specimen holder 33 by eliminating the influence of frictional resistance and sliding resistance in the air cylinder portion 65.
By providing the cooling water channel 75 in the pull rod 67, it is possible to prevent the heat of the test water from being transmitted to the load cell 73 and the air cylinder part 65, to ensure the load load measurement accuracy, and to prevent the test apparatus from occurring.

  The load load generated by the load load portion 37 is set by controlling the pressure of the compressed air supplied to the air cylinder portion 65, but the load load that actually acts on the specimen holder 33 by the load cell 73. Has been confirmed.

  The displacement measuring unit 39 includes a breakage detection laser displacement meter 77 that detects the breakage of each test piece by measuring the displacement of the piston portion 71 of the air cylinder portion 65, and a first laser that measures the displacement of the first holding portion 55. A displacement meter 79 and a second laser displacement meter 81 that measures the displacement of the second holding portion 57 are schematically configured.

The fracture detection laser displacement meter 77 is disposed in the air cylinder portion 65, and is disposed so as to irradiate the piston portion 71 with laser light and measure the displacement in the direction along the central axis C thereof. The first laser displacement meter 79 and the second laser displacement meter 81 irradiate the laser reflection unit 63 of the first holding unit 55 and the laser reflection unit 63 of the second holding unit 57 with laser light through the lid 43, respectively. It arrange | positions so that the displacement to the direction along each center axis | shaft C can be measured.
Each of the laser displacement meters 77, 79, 81 calculates the distance by measuring the time until the emitted laser light is reflected and returned.

Next, the operation of the constant load SCC test apparatus 1 having the above configuration will be described.
First, as shown in FIG. 2, the test pieces 31 </ b> A, 31 </ b> B, and 31 </ b> C are set in the test piece holder 33 of the constant load SCC test apparatus 1, and the test piece holder 33 is set in the test container 35. Thereafter, a constant predetermined load is applied to each of the test pieces 31A, 31B, and 31C by the load application unit 37, and the test water is supplied from the test water tank 7 into the test container 35 as shown in FIG. To start.

During the test, each test piece 31A, 31B, 31C obtained from the displacement measured by each laser displacement meter 77, 79, 81 is monitored.
In this embodiment, when the displacement of the test piece 31 exceeds a predetermined value, it is determined that the test piece is broken, and the time until the test piece is broken is measured.

Specifically, the fracture detection laser displacement meter 77 measures the total displacement of the test pieces 31A, 31B, and 31C, and the first laser displacement meter 79 calculates the total displacement of the test pieces 31B and 31C. The displacement is measured, and the second laser displacement meter 81 measures the displacement of the lower test piece 31C.
Therefore, if the measurement value (displacement) of the breakage detection laser displacement meter 77 is monitored, it can be detected that a breakage has occurred in any of the test pieces 31A, 31B, 31C. After that, by comparing the measured values of the first laser displacement meter 79 and the second laser displacement meter 81, it is possible to identify which test piece caused the fracture.

  After a breakage occurs in any one of the test pieces 31A, 31B, 31C (for example, the upper test piece 31A), the load is first held from the test piece holder 33 via the upper test piece 31A after the breakage. Since it is transmitted to the unit 55, the evaluation of the remaining test pieces 31B and 31C can be continued.

  According to said structure, each test piece 31A, 31B, 31C is arrange | positioned between the some holding | maintenance parts 53, 55, 57, 59 arranged on the central axis C, and each holding | maintenance part adjoins each test piece. By fixing to the same, it is possible to apply the same load to the plurality of test pieces 31A, 31B, 31C at the same time and to apply a compressive stress.

  By measuring the displacement of each holding part 53, 55, 57, 59 in the direction along the central axis C in the displacement measuring part 39, information relating to the deformation of each of the plurality of test pieces 31A, 31B, 31C is obtained. be able to. In addition, by measuring the load applied by the load load unit 37 in the load cell 73, information on the load applied to each of the plurality of test pieces 31A, 31B, 31C can be obtained.

By measuring the change in the distance from the laser displacement meter to the laser reflector 63 using the laser displacement meters 77, 79, 81, information relating to the deformation of the test pieces 31A, 31B, 31C can be obtained.
Since the laser displacement meters 77, 79, 81 are non-contact measuring devices using laser light, the test pieces 31A, 31B, 31B, 31B, 31C, 31C, 31C, 31C, 31C Information related to the deformation of 31C (information related to breakage) can be obtained.
For example, in the case of a contact-type measuring device, the load acting on each test piece 31A, 31B, 31C is reduced by frictional resistance in the measuring device and the load becomes inaccurate. This problem does not occur in the total.

  Since the test pieces 31A, 31B, and 31C are fixed to the holding portions 53, 55, 57, and 59 by the fixing pins 61, the holding portions 53, 55, 57, and 59 are deformed even if the test pieces 31A, 31B, and 31C are deformed. Can continue to be fixed in the same place on the top. Therefore, the plurality of test pieces 31A, 31B, 31C can be continuously arranged on the central axis C, and an accurate load can be continuously applied to the test pieces 31A, 31B, 31C.

Each test piece 31A, 31B, 31C may be fixed through by using a fixing pin 61 in an adjacent holding part or the like, or a recess is formed in each test piece 31A, 31B, 31C. A pin or the like protruding from the portion or the like may be fixed in the recess, and is not particularly limited.
Further, a through hole along the central axis C is formed in the holder main body 53 and each holding portion 55, 57, 59, and a platinum wire or the like is inserted into the through hole, and this platinum wire is connected to each test piece 31A, 31B, Each test piece 31A, 31B, 31C may be fixed by being inserted through 31C.
Furthermore, as shown in FIG. 6, a cylindrical side surface-shaped concave curved surface 56 is formed at a contact portion of the holder main body 53 and each holding portion 55, 57, 59 with each test piece 31 </ b> A, 31 </ b> B, 31 </ b> C, A test piece may be fitted into 56 and fixed to a holder or the like.

  As described above, test water simulating PWR primary cooling water, which is liquid, may be used as the corrosive medium, corrosive gas may be used, corrosive liquid, and its A gas mixture may be used and is not particularly limited.

  As described above, the fracture detection laser displacement meter 77 may measure the displacement in the direction along the central axis C by irradiating the piston portion 71 with the laser beam, or may apply the laser beam to the holder main body 53. Irradiation may be performed to measure the displacement in the direction along the central axis C, and there is no particular limitation.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. 3 and FIG.
The basic configuration of the constant load SCC test apparatus of the present embodiment is the same as that of the first embodiment, but the configuration of the specimen holder is different from that of the first embodiment. Therefore, in this embodiment, only the periphery of the specimen holder will be described with reference to FIGS. 3 and 4, and the description of the environment maintenance unit and the like will be omitted.
FIG. 3 is a longitudinal sectional view illustrating the configuration of the test piece holder in the constant load SCC test apparatus according to the present embodiment. FIG. 4 is a longitudinal sectional view of the specimen holder cut along a plane whose phase is rotated by 90 degrees around the central axis.
In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIGS. 3 and 4, the test piece holder 103 of the constant load SCC test apparatus 101 includes an upper shaft holding portion 105 and an upper cylindrical holding portion 107 that hold the upper test piece 31A, and an upper cylindrical holding portion. The lower shaft holding portion 109 that holds the middle test piece 31 </ b> B together with 107, and the lower cylindrical holding portion 111 that holds the lower test piece 31 </ b> C together with the lower shaft holding portion 109.

The upper shaft holding portion 105 is formed of an attachment shaft portion 115 that is fixed to the attachment portion 113 of the container body 41 and a fixing portion 117 that fixes the upper test piece 31A.
A cap 119 is provided at the tip of the mounting shaft 115 so as to be detachable by screws. The cap 119 is attached to the tip of the mounting shaft portion 115 projecting from the hole by inserting the mounting shaft portion 115 through the hole of the mounting portion 113, and the contact surface between the cap 119 and the mounting portion 113 is formed in a substantially spherical shape. ing.

The attachment portion 113 is provided with a regulating member 121 that regulates the movement of the cap 119 in the direction along the central axis C.
By comprising in this way, the contact surface of the cap 119 and the attaching part 113 forms a joint part, and can support the upper shaft holding | maintenance part 105 so that rotation is possible.

  The fixing portion 117 is formed so as to be movable in a direction along the central axis C in an upper cylindrical holding portion 107 described later, and a substantially rectangular through hole 123 is formed in the fixing portion 117 with respect to the central axis C. It is formed in a direction that is substantially orthogonal (substantially perpendicular to the paper surface in FIG. 3). A test piece 31 </ b> A is disposed in the through hole 123, and an upper stage fixing portion 125 described later is inserted therethrough.

  An upper test piece 31A is arranged on the lower surface (the lower wall surface in FIG. 3) in the through-hole 123, and a fixing pin 61 for fixing the upper test piece 31A is formed at a point where it intersects the central axis C of the lower surface. Is attached. Further, on the side surface (the left and right wall surfaces in FIG. 3) in the through hole 123, a stepped portion 127 whose side surface interval is narrowed toward the surface to which the upper test piece 31A is fixed is formed.

  The upper cylindrical holding part 107 holds the upper test piece 31A together with the cylindrical part 129 in which the above-described upper axial holding part 105 and the lower axial holding part 109 described later are disposed, and the upper axial holding part 105. The upper stage fixing part 125 and the middle stage fixing part 131 that holds the middle stage test piece 31B together with the lower shaft-like holding part 109 are roughly configured.

  A mounting portion is formed on the side surface of the cylindrical portion 129 so that the upper fixing portion 125 and the middle fixing portion 131 are inserted in a direction substantially orthogonal to the central axis C (substantially perpendicular to the paper surface of FIG. At the lower end of the side surface, a laser reflecting portion 63 that reflects a laser beam for measuring the displacement of the test piece is formed so as to extend in a direction away from the central axis C.

  The upper stage fixing part 125 and the middle stage fixing part 131 are formed in a substantially rectangular parallelepiped shape, and at the point where the upper stage fixing part 125 and the middle stage fixing part 131 intersect with the central axis C when attached to the cylindrical part 129, respectively. Fixing pins 61 for fixing the upper test piece 31A and the middle test piece 31B are attached.

  The lower shaft holding part 109 includes a middle stage holding part 133 arranged in the upper cylindrical holding part 107, a lower stage holding part 135 arranged in a lower cylindrical holding part 111 described later, and a middle stage holding part 133. A joint portion 137 that connects the lower stage holding portion 135 is schematically configured.

  The middle stage holding part 133 is formed so as to be movable in the direction along the central axis C in the above-described upper cylindrical holding part 107, and the middle stage holding part 133 has a substantially rectangular through hole 123 on the central axis C. On the other hand, it is formed in a direction substantially orthogonal (substantially perpendicular to the paper surface in FIG. 3). In the through-hole 123, the middle stage test piece 31B is disposed, and the middle stage fixing part 131 is inserted.

A middle stage test piece 31B is arranged on the upper surface (upper wall surface in FIG. 3) in the through hole 123, and a fixing pin 61 for fixing the middle stage test piece 31B at a point where the center axis C of the upper surface intersects. Is attached. Further, on the side surface (the left and right wall surfaces in FIG. 3) in the through-hole 123, a stepped portion 127 whose side surface interval becomes narrower is formed toward the surface on which the middle test piece 31B is fixed.
Further, a laser reflecting portion 63 that reflects a laser beam for measuring the displacement of the test piece is formed at the lower end of the side surface of the middle holding portion 133 so as to extend away from the central axis C.

  The lower stage holding part 135 is formed so as to be movable in a direction along the central axis C in a lower cylindrical holding part 111 which will be described later, and the lower stage holding part 135 has a substantially rectangular through-hole 123 on the central axis C. On the other hand, it is formed in a direction substantially orthogonal (substantially perpendicular to the paper surface in FIG. 3). A lower test piece 31C is disposed in the through hole 123, and a lower fixing part 139 is inserted therethrough.

  A lower test piece 31C is arranged on the lower surface (the lower wall surface in FIG. 3) in the through-hole 123, and a fixing pin 61 for fixing the lower test piece 31C is formed at a point where the lower test piece 31C intersects with the central axis C of the lower surface. Is attached. Further, on the side surface (the left and right wall surfaces in FIG. 3) in the through-hole 123, a stepped portion 127 whose side surface interval becomes narrower toward the surface on which the lower test piece 31C is fixed is formed.

The joint portion 137 includes a protruding portion 141 protruding from the lower holding portion 135 along the central axis C, a groove portion 143 into which the protruding portion 141 is inserted into the middle holding portion 133, and the protruding portion 141 being rotatable to the groove portion 143. The rotary shaft pin 145 to be connected is roughly formed.
The groove portion 143 is formed so as to open upward in the paper surface in FIG. 3, and the rotation shaft pin 145 is substantially perpendicular to the side wall of the groove portion 143 (the direction along the paper surface in FIG. 3 and the left-right direction). Is arranged.
By configuring the joint part 137 in this way, the middle stage holding part 133 and the lower stage holding part 135 are coupled so as to be rotatable about the rotation shaft pin 145 as a rotation center.

The lower cylindrical holding part 111 includes a bottomed cylindrical part 147 in which the lower stage holding part 135 moves in the direction along the central axis C, and a lower stage fixing part that holds the lower stage test piece 31C together with the lower stage holding part 135. A portion 139 and a connecting shaft portion 149 connected to the pull rod 67 are schematically configured.
On the side surface of the bottomed cylindrical portion 147, an attachment portion is formed in which the lower holding portion 135 is inserted in a direction substantially perpendicular to the central axis C (a direction substantially perpendicular to the paper surface in FIG. 3).

An enlarged diameter portion 151 larger than the diameter of the other portion is formed at the tip of the connecting shaft portion 149, and the upper surface of the enlarged diameter portion 151 is formed in a conical shape.
By forming the enlarged diameter portion 151 in this way, the contact portion between the enlarged diameter portion 151 and the pull rod 67 forms a joint portion, and the lower cylindrical holding portion 111 can be supported to be swingable.

The lower stage fixing portion 139 is formed in a substantially rectangular parallelepiped shape, and in a state where it is attached to the bottomed cylindrical portion 147, the lower stage test piece 31B is fixed at a point where it intersects with the central axis C of the lower stage fixing portion 139. A pin 61 is attached.
In the present embodiment, the test pieces 31A, 31B, and 31C are arranged so that the central axis thereof is substantially perpendicular to the paper surface in FIG.

The operation of the specimen holder 103 of the constant load SCC test apparatus 101 having the above configuration will be described.
Each test piece 31A, 31B, 31C is fixed to the test piece holder 103 by fixing pins 61 as shown in FIGS. The attachment shaft portion 115 of the upper shaft holding portion 105 is fixed to the attachment portion 113, and the connecting shaft portion 149 of the lower cylindrical holding portion 111 is connected to the pull rod 67.
The load load generated by the load load portion 37 is transmitted to the connecting shaft portion 149 by the pull rod 67, and the connecting shaft portion 149 is pulled downward in the direction along the central axis C (downward in FIG. 3).

The load applied to the connecting shaft portion 149 is transmitted to the lower test piece 31C via the bottomed tube portion 147 and the lower fixing portion 139. The load applied to the lower stage test piece 31C is transmitted to the middle stage test piece 31B via the lower stage holding part 135 and the middle stage holding part 133. The load applied to the middle stage test piece 31B is transmitted to the upper stage test piece 31A via the middle stage fixing part 131, the cylindrical part 129, and the upper stage fixing part 125. The load load transmitted to the upper test piece 31 </ b> A is transmitted to the attachment portion 113 via the fixed portion 117 and the attachment shaft portion 115.
Therefore, the load load generated by the load load unit 37 is simultaneously transmitted to all the test pieces 31A, 31B, 31C, and the load loads transmitted to the test pieces 31A, 31B, 31C are substantially the same.

  The downward displacement of the connecting shaft portion 149 is transmitted to the lower test piece 31C through the bottomed cylindrical portion 147 and the lower fixing portion 139. The downward displacement transmitted to the lower stage test piece 31C is transmitted to the middle stage test piece 31B via the lower stage holding part 135 and the middle stage holding part 133. The downward displacement transmitted to the middle stage test piece 31 </ b> B is transmitted to the upper stage test piece 31 </ b> A via the middle stage fixing part 131, the cylinder part 129 and the upper stage fixing part 125. The downward displacement transmitted to the upper test piece 31 </ b> A is transmitted to the attachment portion 113 via the fixed portion 117 and the attachment shaft portion 115.

  Therefore, the lower test piece 31C arranged between the lower fixing part 139 and the lower holding part 135, the middle test piece 31B arranged between the middle holding part 133 and the middle fixing part 131, and the upper fixing part 125 and the fixing. A load load in the compression direction acts on the upper test piece 31 </ b> A disposed between the portions 117.

  When any one of the test pieces 31A, 31B, 31C (for example, the lower test piece 31C) breaks, the lower fixing part 139 and the lower surface of the lower holding part 135 approach each other, and the lower fixing part 139 and the step part 127 are brought close to each other. And contact. The load load transmitted to the lower stage fixing part 139 due to the contact between the lower stage fixing part 139 and the stepped part 127 is directly transmitted to the lower stage holding part 135 without passing through the lower stage test piece 31C.

  Therefore, even after the lower test piece 31C is broken, it is possible to continue applying a load to the remaining test pieces 31A and 31B. In addition, since the load load is directly transmitted from the lower stage fixing portion 139 to the lower stage holding portion 135, an accurate load load can be applied to the remaining test pieces 31A and 31B.

  With the deformation of any one of the test pieces 31A, 31B, 31C (for example, the middle test piece 31B), the central axis of the middle test piece 31B, the upper cylindrical holding portion 107 adjacent to the middle test piece 31B, and the lower shaft When a deviation occurs between the central axis of the shape holding part 109, a rotational moment acts on each of the holding parts 107 and 109 due to the deviation of the central axis.

  In the lower shaft holding portion 109, the middle holding portion 133 and the lower holding portion 135 are connected to each other so as to be rotatable in a predetermined direction at the joint portion 137, so that the rotation moment can be absorbed by the joint portion 137. Therefore, it is possible to prevent the middle stage holding part 133 from being pressed against the inner surface of the upper cylindrical holding part 107 due to the rotational moment. As a result, it is possible to prevent an increase in frictional resistance between the middle stage holding portion 133 and the upper cylindrical holding portion 107, and it is possible to prevent a load applied to each test piece 31A, 31B, 31C from being reduced.

Comparing the load-strain characteristics measured by attaching three test pieces with strain gauges to the test specimen holder of this embodiment and the load-strain characteristics measured with a test specimen holder with one test specimen attached Both were almost in agreement. Further, when FEM (Finite Element Method) analysis was performed on the test piece, load-strain characteristics similar to the experimental results were obtained.
From the above results, it is shown that load reduction (friction loss) due to friction between the holding portions 105, 107, 109, and 111 is prevented. In particular, it has been experimentally confirmed that the effect of reducing the load on the middle test piece 31B is great.

  According to said structure, by providing the joint part 137, it can prevent that a rotational moment acts with respect to each test piece 31A, 31B, 31C, and can only apply a compressive load. As a result, each test piece 31A, 31B, 31C can be more accurately evaluated.

  Further, by providing the joint portion 137, it is possible to prevent the fixing portion 117 and the middle stage holding portion 133 from being pressed against the inner peripheral surface of the cylindrical portion 129 and the lower stage holding portion 135 from being pressed against the inner peripheral surface of the bottomed cylindrical portion 147. Therefore, frictional resistance can be prevented from acting on these contact surfaces, and the load acting on each test piece 31A, 31B, 31C can be prevented from being reduced.

  The joint portion 137 may be configured to be rotatable about one axis as described above, or may be configured to be rotatable about two axes orthogonal to each other, and is not particularly limited. .

As described above, the lower shaft-shaped holding portion 109 may be configured by the middle-stage holding portion 133, the lower-stage holding portion 135, and the joint portion 137 that connects them, as shown in FIG. The lower shaft holding portion may be a lower shaft holding portion 209 in which the middle stage holding portion 133 and the lower stage holding portion 135 are integrally formed.
Further, in the test piece holder shown in FIG. 5, a through hole is formed in each holder 105, 107, 209, 111 along the central axis C, and a platinum wire or the like is inserted into the through hole. The test pieces 31A, 31B, and 31C may be fixed by inserting the test pieces through the test pieces 31A, 31B, and 31C.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the description has been made with reference to the constant load SCC test apparatus that applies a constant load to the test piece. However, the load is not limited to the constant load SCC test apparatus, and the load varies with time. It can be applied to other various SCC test apparatuses such as a repetitive load SCC test apparatus.
In the above-described embodiment, the material strength test apparatus and the test method thereof according to the present invention have been described as being adapted to the constant load SCC test apparatus and the test method. However, the present invention is not limited to the constant load SCC test apparatus. The present invention can be applied to various other material strength test apparatuses and test methods, such as tensile test apparatuses and test methods thereof.

1 is a system diagram showing an overall configuration of a constant load SCC test apparatus according to a first embodiment of the present invention. It is the schematic explaining the structure of the stress load part of FIG. It is a longitudinal cross-sectional view explaining the structure of the test piece holder in the constant load SCC test apparatus which concerns on 2nd Embodiment which concerns on this invention. The longitudinal sectional view of FIG. 3 is a longitudinal sectional view of the specimen holder cut along a plane whose phase is rotated by 90 degrees around the central axis. It is a longitudinal cross-sectional view explaining another embodiment of the test piece holder of FIG. It is a longitudinal cross-sectional view explaining another embodiment, such as a holder in the test piece holder of FIG.

Explanation of symbols

1,101 Constant load SCC test equipment (Material strength test equipment)
7 Test water tank (corrosive medium supply means)
9 High-pressure metering pump (corrosive medium supply means)
31 Test piece 31A Upper test piece 31B Middle test piece 31C Lower test piece 35 Test container (housing)
37 Load application section 39 Displacement measurement section 49 Inflow pipe (corrosive medium supply means)
51 Outflow pipeline (corrosive medium supply means)
53 Holder body (holding part)
55 1st holding part 57 2nd holding part 59 3rd holding part 61 Pin for fixing (fixing means)
63 Laser reflector (reflector)
67 Pull rod (shaft body)
73 Load cell (load measuring part)
77 Fracture detection laser displacement meter 79 First laser displacement meter 81 Second laser displacement meter 105 Upper shaft holding portion 107 Upper cylindrical holding portion 109 Lower shaft holding portion 111 Lower cylindrical holding portion 137 Joint portion 209 Lower shaft holding Part C Center axis (predetermined straight line)

Claims (7)

A plurality of holding units arranged on a predetermined straight line;
A plurality of fixing portions that are movable in the direction along the predetermined straight line and extend in a direction substantially orthogonal to the predetermined straight line;
A test piece disposed between the holding part and the fixing part or between the plurality of fixing parts and fixed to the adjacent holding part or the fixing part ;
Applying a load in a direction along the predetermined straight line to the holding part and the fixed part , a load loading part for applying a tensile stress or a compressive stress to the test piece,
A displacement measuring unit that measures a displacement of each of the fixed units in a direction along the predetermined straight line;
A load measuring unit for measuring a load applied by the load applying unit;
At least one of the holding portions adjacent to the test piece, a joint portion that is rotatable about at least one rotation axis extending in a direction intersecting the predetermined straight line and substantially perpendicular to the fixed portion;
A material strength test apparatus characterized by comprising: The displacement measuring unit is a laser displacement meter;
Claim 1 Symbol placement of material strength testing apparatus, characterized in that the reflecting portion for reflecting the laser emitted from the laser displacement meter in the holding portion is provided. The material strength test apparatus according to claim 1 or 2 , wherein at least one of the holding part and the test piece is provided with a fixing means for fixing the test piece to the holding part or the fixing part. . The load load portion includes a shaft that transmits a load to the holding portion,
Material strength testing apparatus according to any one of claims 1-3, wherein the load measuring part is arranged in the shaft. A housing for storing the plurality of holding portions and the test piece therein;
Within the housing, material strength testing apparatus according to any one of claims 1 to 4, characterized in that and a corrosive medium supply means for supplying a corrosive medium. The test piece is formed into a substantially O-shaped or substantially C-shaped tube,
Material strength testing apparatus according to any one of claims 1-5, wherein the load along a direction intersecting with respect to a center axis of the specimen is loaded. A material strength test method using the material strength test apparatus according to any one of claims 1 to 6,
A predetermined load is applied to each test piece by the load load portion,
The load measuring unit measures the predetermined load, and the displacement measuring unit determines the displacement of each test piece by measuring the displacement of each holding unit,
A material strength test method characterized in that the time until the displacement of each test piece reaches a predetermined value is measured.

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