JP2007240212A - Material test piece and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material test piece making it possible to measure the characteristics of a material under various environmental atmospheres by controlling the environmental atmospheres only in the gaps provided to the test piece and constituted so as to perform the evaluation test of the mechanical strength characteristics or environment-resistant characteristics of a structural material even under a usual environment so as to obtain the same result as the evaluation test performed under a peculiar and severe environment, and to provide a method of manufacturing the same. <P>SOLUTION: Constitution characterized in that an environment constituting fluid is enclosed in the fine gaps formed in the test piece is employed in the test piece. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a test piece used in a test method for examining the characteristics of various materials such as metals, alloys, ceramics, and resins under special circumstances, and a method for manufacturing 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 the above, the present invention usually achieves the same results as those performed in a harsh environment that is specific to the mechanical strength characteristics and environmental resistance characteristics of structural materials without requiring a large burden. It is an object of the present invention to provide a test piece and a method for manufacturing the same, which can perform an evaluation test even in an environment of the above.

The test piece according to the first aspect of the present invention employs a configuration characterized in that an environmental constituent fluid is enclosed in a fine gap formed therein.

According to the second aspect of the present invention, in the method of enclosing the environmental constituent fluid in the material test piece of the first aspect, a plastic material is placed in the tube connected to the fine gap in a form that forms a flow path in the tube. In addition, the supply port of the external environmental component fluid supply structure is connected to the tube inlet, the environmental component fluid is injected into the fine gap, and the tube is added while the connection state between the inlet and the supply port is maintained. A configuration was adopted in which the inside of the tube is sealed with the plastic metal body together with the pressure plastic material, and the inlet side is cut from the sealed portion to be separated from the environmental fluid supply structure.

The third aspect of the present invention is the method of enclosing the environmental constituent fluid in the material test piece of the first aspect of the present invention, in which a hot melt material is put in a form that forms a flow path in a tube connected to the fine gap, Connecting the supply port of the external environmental component fluid supply structure and the tube inlet, injecting the environmental component fluid into the fine gap, and heating the tube while maintaining the connection state between the inlet and the supply port Adopted a structure characterized by melting the heat-meltable material, sealing the inside of the tube with this heat-meltable material, cutting the inlet side from this sealed portion, and separating it from the environmental component fluid supply structure .

In the second and third inventions, a configuration is adopted in which the fluid pressure in the fine gap is increased by injecting an environmental constituent fluid in a cooled state and returning to ambient temperature after sealing. .

According to the first aspect of the present invention, since the fluid constituting the desired environmental condition is sealed in the test piece, even if various tests are performed by using a test apparatus in a state generally used conventionally, a special environment is used. We were able to make the same evaluation as we did below.

According to the second aspect of the present invention, when the desired environmental constituent fluid is packed in the test piece, the pressure and other conditions can be contained under the conditions set by the supply structure.
In addition, since no heat is used for the sealing, a special environmental constituent fluid that is denatured by heat can be contained.

According to the third aspect of the present invention, when the desired environmental fluid is packed in the test piece, the pressure and other conditions can be contained under the conditions set by the supply structure.

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

FIG. 1 is a longitudinal side view showing a rod-shaped tensile test piece as an example of the present invention.
The test piece (11) has upper and lower screw parts (12) and (13) for attachment to a tensile tester, and a fine pipe-shaped gap (15) is formed at the center thereof.
A tube (20) is hermetically connected to the lower end of the gap (15), and the inside of the tube (20) is packed with a metal rod (21) which is an example of a pressure plastic material.
In this way, the environmental constituent fluid, for example, high-pressure liquid such as high-pressure hydrogen gas, high-pressure gas or high-pressure water, sealed in the gap (15) is sealed at the set pressure.

A method for containing the environmental constituent fluid in the test piece (11) in this way will be described with reference to FIGS.
As shown in FIG. 3, a metal rod (21) having a smaller diameter than the inner diameter is placed in a tube (20) having one end connected to the test piece (11).
Next, the joint (250c) is fixed to the free end of the tube (20) through the cap nut (250b) of the pipe joint (250).
The connector (250a) of the pipe joint (250) is fixed to the distal end of the main flow path (201) of the environment constituent fluid supply structure shown in FIGS.
In this way, the tube (20) is connected to the structure for supplying environmental constituent fluid via the pipe joint (250), and the desired environmental constituent fluid is fed into the gap (15).
When the desired state is reached, the tube (20) and the metal rod (21) are pressed together and sealed by the pressing machine (25) as shown in FIG.
Thereafter, the pipe joint (250) is released (the state shown in FIG. 5), and the excess portion of the tube (20) is cut off to obtain the test piece (11) shown in FIG.
Depending on conditions such as the pressure of the environmental constituent fluid, a soft tube (20) may be used. In such a case, as shown in FIG. 6, without using the metal rod (21), It can be contained only by plastic deformation (20 ′) of the tube (20).

In this embodiment, the tube (30) is sealed with a molten metal rod (31) which is an example of a heat-meltable material.
This containment method will be described below.
Instead of the tube (30) having one end of the U-shape connected to the gap (15), a molten metal rod (31) having a smaller diameter than this tube (30) is inserted, and the other end is connected to the environment via the pipe joint (250). Connect to the fluid supply structure.
When the environmental constituent fluid is supplied until a predetermined state is reached, the bent portion of the tube (30) is heated by a burner (35) to melt the molten metal rod (31), and is cooled by flowing through the bent portion. The part is sealed.
Since the other points are the same as those of the first embodiment, description thereof is omitted.
In the example shown in FIG. 10, the inclination angle of the test piece (11) at the time of melting the molten metal rod (31) is set to about 30 °. As shown, the metal (31) could be poured into a part of the gap (15), and the tube (30) could be sufficiently contained even if the portion protruding from the test piece (11) was almost excised. .
The inclination angle is preferably set in a range of about 30 ° to 80 °.
Further, if the melted viscosity is such that it does not flow deep into the gap (15), it is possible to work with an inclination angle of 90 °.
Further, the heating means is not limited to a burner, and a hot air machine, an electric heater, or the like can be used as appropriate.

The present embodiment shows an example of a structure for supplying an environmental constituent fluid (high pressure gas) used in both embodiments.
The environmental fluid supply structure includes a gas cylinder (202), the pipe joint (250), and a main flow path (201) connecting them.
An excess gas exhaust pipe (204) is branched into the main flow path (201).
In addition, a flow path leading to a vacuum tank (208) for replacing the gas in the pipe is also branched, and an open / close valve (205) (207) is provided in each branch flow path.
In addition, on-off valves (203) (206) are also provided on the upper and lower sides of the branch portion in the main channel (201).
The lower-side on-off valve (206) is set to automatically close when the result of pressure measurement by the pressure sensor (209) provided nearby indicates a rapid pressure reduction.
A temperature adjustment device (256) for adjusting the temperature of the fluid flowing in the main flow path (201) is provided on the lower side of the pressure sensor (209).
Further, a hand opening / closing valve (255) is provided on the lower side.
In this way, by opening the on-off valves (203) (206) (255), the gas (for example, high-pressure hydrogen, high-pressure oxygen, etc.) packed in the gas cylinder (202) is discharged from the pipe joint (250) to the gap ( 15), the void (15) inner surface of the test piece (11) could be brought into a state similar to that exposed to the desired environment.
Note that a pressure adjusting mechanism such as a regulator is installed in the gas cylinder (202), but these are well-known items and will not be described.

This embodiment shows another example of the supply structure of the environmental constituent fluid (high pressure gas) used in both the above embodiments.
An on-off valve (206) and a pressure sensor (209) are provided in the middle of the main flow path (201) from the discharge pump (202b) provided at the outlet of the storage tank (202a) to the pipe joint (250).
Further, a temperature adjusting device (256) and a hand opening / closing valve (255) are provided on the lower side of the pressure sensor (209).
In this way, fluid such as water, acid, hydroxide, salt water, etc., stored in the storage tank (202a) is supplied to the gap with a predetermined pressure by the discharge pump (202b), and the on-off valve (255) is operated. So we can create a special environment in the gap.

In Examples 3 and 4, when the environmental constituent fluid is supplied to the air gap while cooling the test piece with liquefied nitrogen or the like, the gas can be supplied at high density.
As a result, when it was returned to room temperature, it became possible to create an extremely high pressure environment inside the test piece compared to the pressure at the time of supply.

In the present embodiment, three gaps (15a), (15b) and (15c) are formed and connected to the same tubes (30a), (30b) and (30c) as in the second embodiment. And sealed in the same manner.
Since other points are the same as those of the second embodiment, description thereof is omitted.
In this case, it is also possible to contain different environmental constituent fluids in the three gaps (15a) (15b) (15c).

  In the present example, voids (15a), (15b), and (15c) are formed in a pipe-shaped test piece (11a), and the others are the same as those in Example 5, and therefore the description thereof is omitted.

  In this example, voids (15a), (15b), (15c), and (15d) are formed in a prismatic test piece (11b).

In this example, a test piece (511) used in a test machine for impact test is provided with a gap (515), and a tube (20) similar to the tube shown in Example 1 is connected to the gap to form a metal. It is sealed with a stick (21).
Others are the same as those in the first embodiment, and the description is omitted.

This example shows an example of a test piece for fracture toughness / fatigue crack growth test.
The test piece (411) is a test piece for fracture toughness / fatigue crack propagation test, and is parallel to the crack starting groove (412), and pipe-shaped voids (415a) (415b) above and below the planned crack location. ) Is formed.
Tubes (31a) and (31b) similar to those of the second embodiment are provided at one end portions of the gaps (415a) and (415b), respectively.
Others are the same as those in the second embodiment, and a description thereof will be omitted.
In this way, the present invention can be implemented even in fracture toughness / fatigue crack growth tests.

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.

  Further, the number of voids provided in the test piece may be 1, 2, 3, 4 or more.

As the material of the tube (20) 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 (21) put in the tube (20), the following is suitable.
Indium, annealed copper, silver or lead.

The following materials are suitable as the material of the tube (30) having heat resistance 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 (31) to be put in the tube (30), the following is suitable.
Solder alloy, wood metal, silver solder or heat-meltable resin.

  The diameter (d) of the air gap (15) is 2 mm or less, and the cross-sectional area of the test piece (π × D × D ÷ 4 in Example 1) is sufficiently 1 or less. It is preferable for safe testing without causing errors.

  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.
In addition, by injecting and discharging the above liquids and gases into the voids and performing various tests while changing the environmental atmosphere over time, the material properties under various environmental atmospheres, especially in severe environmental atmospheres, are measured. It is also possible to do.

A mechanical test load such as tensile force, compressive force, bending, impact, etc. is applied to the material test piece from the outside.
Depending on the purpose of the test, the present invention does not prevent heating / cooling from the outside of the test piece when it is necessary to consider not only the environment in the gap but also the temperature outside the test piece. Absent.

As a compression machine, as shown in FIGS. 22 and 23, the diameter of the tube (20) may be contracted and pressed against the internal metal (21) to be sealed.
Specifically, a cap nut (601) having a hole through which the tube (20) is inserted, and a flange (602) having an insertion hole (602a) in which the port on the cap nut side extends in a conical shape through the tube (20). And a conical piece (603) whose surface is a tapered surface along the inner surface of the insertion hole (602a), and a hole through which the tube (20) is inserted at the center of the piece (603). Yes.
The cap nut (601) and the flange (602) are made of hard tool steel, and the piece (603) is made of stainless steel harder than the tube (20).
In this way, in the same manner as in Example 1, when the gas is supplied and then the cap nut (601) is tightened, the conical piece (603) is reduced, and the tube is softer than this. (20) also reduces the diameter.
As a result, the inner surface of the tube (20) is pressed against the internal metal rod (21), and the encapsulation is completed.
By doing in this way, what has no pressure plasticity can be used for a metal rod (21).

Field of application of the present invention

  Thus, in the method of the present invention, it is possible to measure the characteristics of materials under various environmental atmospheres by controlling the environmental atmosphere only in the voids provided in the test piece. In addition, since the gas or liquid is filled only in the gap provided in the test piece, it has an excellent feature that the burden on management and processing is extremely small.

Longitudinal front view showing the tensile test piece of Example 1 A = A sectional view of FIG. Longitudinal front view during injection of environmental constituent fluid into the test piece of Example 1 AA sectional view of FIG. Longitudinal front view showing a state in which an environmental constituent fluid is contained in the test piece of Example 1 In Example 1, a longitudinal front view showing an example in which a tube with good plasticity can be used Longitudinal front view showing a tensile test piece of Example 2 Longitudinal front view during injection of environmental constituent fluid into the test piece of Example 2 AA sectional view of FIG. Longitudinal front view showing a state in which an environmental constituent fluid is contained in the test piece of Example 2 In Example 2, the longitudinal front view which shows the example which does not leave a tube Piping diagram showing the outline of Example 3 Piping diagram showing the outline of Example 4 Cross-sectional plan view of the test piece of Example 5 Bottom view of Example 5 Cross-sectional plan view of the test piece of Example 6 Bottom view of Example 6 Cross-sectional plan view of the test piece of Example 7 Bottom view of Example 7 Longitudinal front view of Example 8 Vertical front view of Example 9 Longitudinal front view showing reduced diameter compression machine and its usage Longitudinal front view showing the compressed state of the tube with a reduced diameter compression machine

Explanation of symbols

(11) (11a) (411) (511) Test piece (12) (13) Screw part (15) (15a) (15b) (15c) (15d) (415a) (415b) (515) Air gap (201) Main channel (202) Gas cylinder (202a) Storage tank (202b) Discharge pump (203) (206) (255) (205) (207) On-off valve (204) Surplus gas exhaust pipe (208) Vacuum tank (209) Pressure Sensor (20) (30) (30a) (30b) (30c) (31a) (31b) Tube (21) Metal rod (pressure plastic material)
(25) Pressure machine (31) Molten metal rod (heated molten material)
(35) Burner (250) Pipe joint (250a) Connector (250b) Cap nut (250c) Joint (255) Hand on-off valve (256) Temperature control device (412) Crack starting groove (600) Reduced diameter type compression device ( 601) Cap nut (602) Flange (602a) Pipe insertion hole (603) Cone piece

Claims (4)

A material test piece used for a load test for evaluating the characteristics of a material, wherein an environmental constituent fluid is enclosed in a fine void formed in the test piece. 2. The method of enclosing environmental constituent fluid in the material test piece according to claim 1, wherein a pressurized plastic material is placed in a tube connected to the fine gap in a form to form a flow passage in the tube, and then externally. Connecting the supply port of the environmental component fluid supply structure and the tube inlet, injecting the environmental component fluid into the fine gap, and maintaining the connected state between the inlet and the supply port, the tube is compressed plastic material And the tube is sealed with the plastic metal body, and the inlet side is cut from the sealed portion to separate from the environmental fluid supply structure. 2. A method for enclosing an environmental constituent fluid in a material test piece according to claim 1, wherein a hot-melt material is placed in a tube connected to the fine gap in the form of a flow passage, and then an external environmental constituent fluid is used. Connecting a supply port of the supply structure and the tube inlet, injecting an environmental constituent fluid into the fine gap, and heating the tube while maintaining a connection state between the inlet and the supply port, thereby producing a heat-meltable material. Melting and sealing the inside of the tube with this hot-melt material, cutting the inlet side from the sealed portion, and separating it from the environmental fluid supply structure, The method for producing a material test piece according to claim 2 or 3, wherein the fluid pressure in the fine gap is increased by injecting an environmental constituent fluid with the test piece cooled and returning to normal temperature after sealing. Method for manufacturing material specimens