JP4775706B2 - Environmental resistance characteristic evaluation tester with pressure chamber and test method using the same - Google Patents

Description

  The present invention relates to a testing machine with a pressure chamber capable of performing a load test on a test piece in a state of being placed in a pressure chamber and a test method using the same.

  When new materials are developed or when existing materials are used in a special environment, it is essential to accurately evaluate the properties of the material under its specific environmental atmosphere. In particular, in the case of a structural material that requires high mechanical strength characteristics and environmental resistance characteristics, it is required to have excellent characteristics under an environment under various conditions. For example, the purpose and use of the member Depending on the type, not only mechanical strength properties such as tensile properties, fatigue properties, fatigue crack growth properties, creep properties, fracture toughness properties, impact properties, but also acid resistance, alkali resistance, oxidation resistance, corrosion resistance, etc. Excellent environmental resistance is also required. Moreover, for structural materials, these characteristics are not limited to mild environments such as normal temperature and normal pressure, but also in harsh environments such as high temperature to low temperature, high pressure to low pressure, and even acidic and alkaline environments. It is required to have excellent characteristics. For this reason, it is necessary to evaluate the characteristics of the material in an environmental atmosphere under specific and various conditions.

  Conventionally, as shown in Patent Documents 1 to 4, when testing mechanical strength characteristics and environmental resistance characteristics of materials in a harsh environment, a sealed space in which the temperature and pressure of the test piece can be arbitrarily adjusted. A test apparatus is installed in the space, and a fluid that constitutes a special environment in the space (for example, high pressure gas, high pressure liquid, high temperature gas, high temperature liquid, etc., these are collectively referred to as environment constituent fluid) is sent from the outside I could only do the test.

Such a method not only requires a large amount of equipment and cost to create and maintain the environment necessary for measurement, but also it is difficult to accurately apply the load and reagent for the test. The fact is that it has not yet been established as a method for obtaining valid data.
: JP 09-196844 A : JP 2004-132752 A : JP 2001-208675 A : JP 2004-072230 A

  In view of such circumstances, the present invention not only suppresses the amount of fluid used in a special environment as much as possible, but also prevents an accident caused by a high-pressure fluid by generating a high-pressure state in the pressure-resistant chamber. The purpose is to.

The environmental resistance characteristic evaluation tester with a pressure chamber according to the first aspect of the present invention is provided with a flexible partition wall that seals the space around the test piece and the space inside the other pressure chamber in a sealed state. A configuration characterized by injecting a fluid constituting a special environment into the space was adopted.

  The test method of the second invention is a test method using the testing machine of the first invention, wherein a high-pressure fluid is injected into a space outside the partition wall, and the pressure in the space around the test piece is tested through the partition wall. A configuration characterized by pressurizing to a pressure according to the purpose was adopted.

According to the first aspect of the present invention, since the fluid for constructing the special environment can be stored only in the space around the test piece, the amount of use of these fluids is greatly reduced compared to storing in the entire pressure-resistant chamber. This is effective for saving resources.
Furthermore, by conducting the test as in the second invention, it is not necessary to use a high pressure even when injecting the environmental constituent fluid from the outside, and the opportunity to handle the high-pressure fluid is reduced, making it easy to protect the safety of the test site.

  Further, the high pressure is performed in a pressure resistant chamber, and environmental tests under high pressure are possible.

  The present invention has the features as described above, and an embodiment thereof will be described below.

This testing machine is a tensile testing machine, which holds the testing machine base (12) in the middle of the pillars (11) and (11) erected on the base (10), and has a crosshead (13) at its upper end. The structure is formed by holding.
A pull rod (15) is held on the surface plate (12), and a fixed jig (18) is held on the cross head (13).
The pull rod (15) is configured to be movable up and down by an actuator (14) supported by the surface plate (12), and is provided with load cells (16) and (17) for load measurement.
The pressure chamber (20) includes a door (21) that opens and closes, a hole (22) through which a bolt (not shown) for fixing the door in a closed state, and a screw hole (23) into which the bolt is screwed. is there.
A lower end portion of the fixed side jig (18) protrudes from a ceiling portion in the pressure resistant chamber (20), and an upper end of the pull rod (15) is pressure resistant by an O-ring (19) on the floor portion. Sealed and protruding.
(24) is a pressure gauge that measures and displays the pressure in the pressure-resistant chamber (20), and (25) is a leak valve that releases excess pressure in the pressure-resistant chamber (20).
A heat exchanger (32) connected to a pipe (31) from a temperature controller (30) for controlling the temperature in the pressure-resistant chamber (20) is installed in the heat-resistant chamber, and the pump (42) is supplied from the storage tank (41). A pipe (43) extending into the heat-resistant chamber through a passage valve (44) is provided.
The liquid (usually clean water) stored in the tank (41) is sent into the pressure resistant chamber (20) by the pump (42) to increase the pressure in the chamber.

(1) is a bar-shaped test piece held by the upper jig (17) and the pull rod (15).
In the test piece (1), the upper and lower sides of the partition wall (2) are tightly fixed by the fastening band (6).
The partition wall (2) has a ball shape in which the mouth portions (2a) and (2a) that pass through the end portion of the test piece (1) and are in close contact with the periphery are formed vertically, and are formed of rubber or an elastic resin sheet. It is.
The band (6) is constituted by a bolt (6c) passing through flanges (6b) and (6b) provided at both ends of the band body (6a) and a nut (6d) into which the bolt (6c) is screwed. The inner diameter of the band body (6a) can be changed by tightening or loosening the bolt (6c).
In this way, the space around the test piece (1) and the space in the other pressure-resistant chamber (20) are partitioned in a sealed manner.
(3) is an entrance / exit of the ball-shaped partition wall (2), which is closed by a clip (4).

Since it is configured in this manner, a fluid constituting a special environment such as argon, hydrogen, oxygen, or the like is injected into the partition wall (2) at normal pressure or slightly high pressure, and then the pump (42) By pressurizing, the internal environmental constituent fluid was pressurized through the partition wall (2), and a high pressure state suitable for the purpose of the experiment could be achieved.
By conducting a tensile test in this state, the material could be evaluated in a special environment.
In this case, the amount of the environmental constituent fluid used was several tenths or less from the viewpoint of filling the entire pressure resistant chamber (20).
In addition, pressurization from the outside of the pressure-resistant chamber (20) is safer because no environmental constituent fluid is used.

The present embodiment shows an example of the embodiment that is implemented in the first embodiment when the partition wall (2) may be in close contact with the internal test piece (1) due to pressurization.
The balloon-shaped preliminary storage body (62) and the partition wall (2) were connected via a hose (51) to substantially increase the capacity of the partition wall (2).
The preliminary storage body (62) is made of a flexible material similar to that of the partition wall (2), and its doorway (63) can be opened and closed with a clip in the same manner as the doorway (3) of the partition wall (2). It is.
The rest is the same as in the first embodiment, and a detailed description thereof will be omitted.
In this way, by storing the same environmental constituent fluid in the preliminary reservoir (62) and the partition wall (2) in advance, the pressurization ratio (ratio between the initial pressure in the partition wall and the pressure during the test) can be set. Even when the height was increased to nearly twice that of Example 1, the problem that the partition wall (2) was in close contact with the test piece (1) was prevented.

The present embodiment is an example in which a test under a more specific condition can be performed.
An outlet (70) of the main channel (81) from the gas cylinder (80) is provided in the pressure-resistant chamber (20), and the outlet (70) and the inlet / outlet (3) of the partition wall (2) are connected to the pipe (52). The high-pressure gas can be directly supplied from the gas cylinder (80) into the partition wall (2).
An excess gas exhaust pipe (86) is branched into the main flow path (81).
Moreover, the flow path connected to the vacuum tank (89) for replacing the gas in the pipe is also branched, and an open / close valve (83) (85) is provided in any branch flow path.
In addition, on-off valves (82) and (84) are also provided on the upper and lower sides of the branch portion in the main flow path (81).
The lower-side on-off valve (84) is set to automatically close when the result of pressure measurement by the pressure sensor (90) provided nearby indicates a rapid pressure reduction.
Further, a hand opening / closing valve (91) is provided on the lower side.
In this way, by opening the on-off valves (82), (84), and (91), gas (for example, high-pressure hydrogen, high-pressure oxygen, etc.) packed in the gas cylinder (80) is discharged from the outlet (70) to the partition wall (2 ).

A present Example shows another example of a partition (2).
In this embodiment, when a partition is formed using a material that is flexible but has low elasticity, such as a cloth coated with an airtight resin, it can be scaled according to pressure. The whole is formed in the shape of a rugby ball, and irregularities (2c) and (2d) are formed on the side surfaces thereof.
In this way, the internal space can be accommodated regardless of the elasticity of the fabric.

This example shows an example in which the present invention is applied to a specimen for fracture toughness / fatigue crack growth test.
The test piece (411) is a test piece for fracture toughness / fatigue crack propagation test, and tests the occurrence of cracks from the crack starting groove (412).
In this embodiment, the crack occurrence predicted portion is covered with the partition wall (2).
Specifically, a bag-like partition wall (2) in which a mouth portion (2a) having the same shape as the cross section of the crack occurrence predicted portion is vertically attached is attached by a band (6).
Other details are the same as in the first embodiment, and a detailed description thereof will be omitted.

This example shows an example in which an opening (3a) leading to the inside of the partition wall (2) is provided in the test piece (1) without providing a mouth portion in the partition wall (2).
A thin inlet (3a) extending from the end surface to the intermediate portion is formed at one end of the test piece (1).
Then, one end of a U-shaped tube (3b) is connected to the inlet (3a). The other end of the tube (3b) is connected to a gas supply path via a pipe joint (110).
The tube (3b) contains a hot-melt metal rod (3c) having a smaller diameter.
In this way, when the environmental constituent fluid is supplied via the pipe joint (110), it is stored in the partition wall (2).
When the environmental constituent fluid is supplied until a predetermined state is obtained, the bent portion of the tube (3b) is heated by the burner (35) to melt the hot-melt metal rod (3c), and is then poured into the bent portion to be cooled. , The part is sealed.
Thereafter, the tube (3b) is cut to eliminate unnecessary portions for the test.
In this way, after the desired environmental constituent fluid is sealed in the partition wall (2), the test piece (1) is set in the pressure-resistant chamber (20).
Even if the tip of the tube (3b) protrudes from the end face of the test piece (1), it can be applied to the implementation of the present invention by the test piece mounting structure of the tester.
In addition, the inlet (3a) may be closed by pressing the tube (3b) with a pressing machine, not limited to heat melting.

As the material of the tube (3b) that can be deformed by compression, the following materials are suitable in that they can be easily deformed by compression with a compression machine while withstanding high pressure.
SUS304 or SUS316 stainless steel pipe, copper pipe, brass pipe or hard resin pipe.

Further, as the pressure plastic material (3c) put in the tube (3b), the following is suitable.
Indium, annealed copper, silver or lead.

The following materials are suitable as the material of the heat-resistant tube (3b) that can withstand heating.
SUS304 or SUS316 stainless steel pipe, steel pipe, copper pipe, brass pipe, aluminum pipe, etc.

Further, as the heat-meltable material (3c) put in the tube (3b), the following is suitable.
Solder alloy, wood metal, silver solder or heat-meltable resin.

Other examples

  In addition to the above-described embodiments, test pieces such as flat plate test pieces and bending test pieces can be used in a special environment by adopting the same configuration.

The environmental constituent fluid is considered as a material that may exert effects such as corrosion, embrittlement, and deterioration on the technical test piece. Examples of the gas include hydrogen, oxygen, halogen (fluorine, chlorine, bromine, iodine) gas, acidic gas, basic gas, water vapor, SF6, sulfur compound, or a mixture thereof. Examples of the liquid include acids, alkalis, chlorides, seawater, body fluids, water, and various mixtures (mists) of liquid and gas.
As a temperature range given to such an environmental constituent fluid, for example, a range of −269 ° C. to 1000 ° C. and a pressure range of 300 MPa to ^{10 −10} Pa are exemplified.
Of course, the present invention is not limited to the above examples.

  A mechanical test load such as tensile force, compressive force, bending, impact, etc. is applied to the material test piece from the outside.

  In addition to water, oil or the like can be used as a fluid for pressurization in the pressure resistant chamber (20).

  In the field of material testing, the present invention enables a load test under a special environment to be effectively performed using a conventional testing machine with a pressure-resistant chamber (20), while achieving safety and resource saving. It is used effectively.

Partially cutout schematic front view showing the entirety of Example 1 Partially cut away enlarged front view showing the main part of Example 1 Enlarged front view of the main part of the band Partially cut away enlarged front view showing the main part of Example 2 Partially cutout schematic front view showing an outline of Example 3 Partially cutaway plan view showing a partition wall of Example 4 The front view which shows the partition of Example 4 Partially cutaway front view showing the main part of Example 5 AA sectional view of FIG. Longitudinal front view showing injection of environmental constituent fluid of Example 6 AA sectional view of FIG. Longitudinal front view showing gas containment of Example 6 Longitudinal front view showing the main part of the completed test piece of Example 6

Explanation of symbols

(10) Base (11) Pillar (12) Surface plate (13) Cross head (14) Pull rod (15) Actuator (16) (17) Load cell (18) Fixing side jig (19) O-ring (1) (411 ) Test piece (412) Crack initiation groove (20) Pressure chamber (21) Door (22) Hole (23) Screw hole (30) Temperature controller (31) (44) Pipe (32) Heat exchanger (35) Burner (2) Bulkhead (2a) Mouth (3a) Inlet (2c) (2d) Concavity and convexity (3) (63) Entrance / exit (3b) Tube (3c) Molten metal rod (heat-meltable material / pressure plastic material)
(4) Clip (6) Band (6a) Band body (6b) Flange (6c) Bolt (6d) Nut (41) Storage tank (42) Pump (43) Pipe (44) Valve (51) Hose (52) Pipe (62) Preliminary reservoir (70) Outlet (80) Gas cylinder (81) Main flow path (82) (84) (83) (85) On-off valve (86) Excess gas exhaust pipe (89) Vacuum tank (90) Pressure Sensor (91) Hand on-off valve (110) Pipe fitting

Claims (2)

In the environment resistance evaluation machine with a pressure chamber capable of performing a test for applying a tensile stress or a repeated tensile stress load to the test piece in a pressure chamber, a space around the test piece and a space in another pressure chamber An environment-resistant characteristic evaluation tester with a pressure-resistant chamber, characterized in that a flexible partition wall is provided that is sealed in a sealed state, and a fluid constituting a special environment is injected into a space around the test piece in the partition wall. The test method using the environmental resistance characteristic evaluation tester with a pressure chamber according to claim 1, wherein a high-pressure fluid is injected into a space outside the partition, and the pressure in the space around the test piece is tested through the partition. A test method characterized by pressurizing to a pressure according to.