JP5219155B2 - Sample strength test apparatus and sample strength test method - Google Patents

Description

  The present invention relates to a sample strength test apparatus and a sample strength test method for testing the relationship of hydrogen on delayed fracture of a sample.

  It is known that a high strength metal may cause delayed fracture when it is strengthened by prestressing. Delayed fracture is a phenomenon in which a metal suddenly breaks after a certain period of time with a load below a critical stress. As one of the mechanisms, a phenomenon called hydrogen embrittlement is known. Delayed fracture is said to be more sensitive to steel with higher strength (tensile strength of 1200 MPa or more). The analysis method is known to investigate the relationship between defects (hydrogen embrittlement) caused by hydrogen, which is a typical example of delayed fracture (see, for example, Non-Patent Document 1).

K. Takai, H .; Shoda, H .; Suzuki, M.M. Nagamo: “Lattice defects dominating hydrogen-related failed of metals”, Acta materiallia, 56, 5158-5167 (2008).

  When investigating the relationship between delayed fracture and hydrogen embrittlement for a sample, there are many temperature adjustment processes for controlling the temperature of the sample, hydrogen charging process for supplying hydrogen to the sample, tensile (compression) strength test process by material tension (compression) test, etc. Process steps are required. In addition, it is necessary to combine them at the same time. In particular, in a test of a large metal wire rod, a processing apparatus that performs each process becomes large, and the following problems exist in order to perform each process while changing the processing conditions.

  First of all, a plurality of apparatuses are necessary. In addition to attaching samples to these apparatuses, the apparatus must be maintained and managed, and there is a problem that an operator skilled in handling the processing apparatus is necessary. Furthermore, there is a problem that it is difficult to control environmental conditions such as the temperature and humidity of the sample when the sample is moved between the plurality of apparatuses.

  Therefore, an object of the present invention is to provide a sample strength test apparatus and a sample strength test method capable of automatically examining the relationship regarding the influence of hydrogen on delayed fracture.

  In order to achieve the above object, the sample strength test apparatus according to the present invention integrates a hydrogen charging unit, a temperature control unit, and a movable mechanism so that a hydrogen charging step, a heating step, and a stress applying step can be automatically performed. I decided to make it.

  Specifically, in the sample strength test apparatus according to the present invention, a rod-shaped sample penetrates the inside thereof, and the sample has a water tank movable in the longitudinal direction, and hydrogen that charges the sample in the water tank is charged with hydrogen. A temperature control unit that is disposed in a longitudinal direction of the sample, the sample penetrates the inside thereof, and the sample has a temperature chamber movable in the longitudinal direction, and heats the sample in the temperature chamber; And moving the sample in the longitudinal direction so that a desired portion of the sample can be charged with hydrogen by the hydrogen charging unit, or the desired portion of the sample can be heated by the temperature control unit, And a movable mechanism that applies stress in the direction.

  This sample strength test apparatus can move a sample between a hydrogen charge part and a temperature control part with a movable mechanism. Furthermore, the movable mechanism can apply stress to the sample. By controlling the hydrogen charging unit, the temperature control unit, and the movable mechanism with a computer or the like, the sample strength test apparatus provides a hydrogen charging step in which hydrogen is charged by supplying hydrogen to a part of the longitudinal direction of the rod-shaped sample; A moving step of moving the hydrogen-exposed portion of the sample that has been hydrogen-charged in the hydrogen charging step to a position where heat treatment can be performed in the longitudinal direction of the sample; and heating that heats the hydrogen-exposed portion of the sample after the moving step It is possible to automatically perform a sample strength test method for performing a step and a stress applying step of applying stress in the longitudinal direction of the sample together with the heating step or after the heating step.

  Therefore, the present invention can provide a sample strength test apparatus and a sample strength test method capable of automatically examining the relationship regarding the influence of hydrogen on delayed fracture.

  The said water tank of the said hydrogen charge part of the sample strength test apparatus which concerns on this invention can be made into the structure where the liquid in the said water tank and the said sample surface in the said water tank contact. The sample can be efficiently charged with hydrogen.

  Furthermore, it is preferable that the hydrogen charging unit of the sample strength test apparatus according to the present invention further includes means for filling the water tank with the liquid and discharging the liquid from the water tank. The sample strength test apparatus can move the sample without retracting the water tank.

  Furthermore, it is preferable that the hydrogen charging unit of the sample strength test apparatus according to the present invention further includes means for electrolyzing the liquid and generating hydrogen.

  Since the hydrogen charging unit of the sample strength test apparatus has these means, the hydrogen charging step introduces a liquid into a water tank through which the sample penetrates, and brings the sample surface into contact with the liquid; A process of electrolyzing the liquid to generate hydrogen and a process of discharging the liquid from the water tank can be performed in order. In the sample strength test apparatus, the hydrogen charge amount can be easily controlled to a desired value by the hydrogen charge unit.

  In addition, it is preferable to further perform a cleaning process for cleaning the surface of the sample between the hydrogen charging process and the heating process. By removing the liquid adhering to the sample surface, it is possible to prevent contamination around the apparatus and in the temperature bath.

  It is preferable that the temperature control unit of the sample strength test apparatus according to the present invention further has a structure capable of introducing gas or liquid from the outside into the temperature bath. It is possible to control the temperature of the sample by sending air controlled to a predetermined temperature, or to wet or dry the sample by sending air controlled to a predetermined humidity. Furthermore, the sample can be corroded by flowing a corrosive gas or solution, and the sample can be washed by flowing a degreasing organic solvent such as ethanol or acetone.

  In the sample strength test apparatus according to the present invention, it is preferable that the hydrogen charge unit, the temperature control unit, and the movable mechanism are arranged so that the longitudinal direction of the sample is a gravity direction. The sample strength test can be performed without considering the deflection of the sample due to gravity.

  The present invention can provide a sample strength test apparatus and a sample strength test method capable of automatically examining the relationship regarding the influence of hydrogen on delayed fracture. This sample strength test apparatus can downsize the entire apparatus scale, and can facilitate the sample strength test by automatically controlling each step of the sample strength test method. In addition, since the sample strength test apparatus can operate the temperature control unit, the hydrogen charge unit, and the movable mechanism in a coordinated manner, a tensile stress test is performed while changing the sample temperature, and a compression test is performed while changing the hydrogen charge amount. It becomes possible to inspect the relationship between sample strength and hydrogen embrittlement under many conditions. In addition, this sample strength test apparatus can eliminate the work of skilled workers, which was necessary in the past, and suppresses the phenomenon of sample contamination in the air and diffusion of charged hydrogen caused by moving the sample. Thus, the test can be performed more accurately.

  The hydrogen charged to the sample diffuses about 1 mm per day. Since this sample strength testing device can perform the hydrogen charging process, moving process, heating process, and stress applying process continuously, the test can be performed before hydrogen diffuses, and accurate hydrogen concentration results can be obtained. it can. Furthermore, the sample strength test apparatus can perform a tensile test while performing hydrogen charging, which has been impossible in the past. This allows a test to be performed before hydrogen escapes from a hydrogen-charged sample, and results with an accurate hydrogen concentration can be obtained. In addition, the sample strength test apparatus can charge hydrogen from the side surface of the sample while pulling the sample up and down, or can stop the hydrogen charge, and can increase the parameters of the test conditions. Thus, the present sample strength test apparatus has a unique effect that a test closer to reality can be performed by combining each test process.

It is a schematic block diagram explaining the sample strength test apparatus which concerns on this invention. It is a schematic block diagram explaining the hydrogen charge part of the sample strength test apparatus which concerns on this invention.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components.

  FIG. 1 is a schematic configuration diagram illustrating a sample strength test apparatus according to this embodiment. The sample strength test apparatus has a water tank 21 in which a rod-shaped sample 91 penetrates the inside and the sample 91 is movable in the longitudinal direction, and a hydrogen charging unit 11 for hydrogen-charging the sample 91 in the water tank 21; A temperature control unit 12 that heats the sample 91 in the temperature bath 31, and the sample 91 has a temperature bath 31 that is movable in the longitudinal direction. The sample 91 is moved in the longitudinal direction so that the hydrogen charging part 11 can be charged with hydrogen by the hydrogen charging unit 11 or the desired part of the sample 91 can be heated by the temperature control unit 12, and stress is applied in the longitudinal direction of the sample 91. And a movable mechanism (13A, 13B) to be provided.

  The sample 91 is, for example, a metal rod. The sample 91 is arranged so that the longitudinal direction is the direction of gravity. The connecting portion 14A and the connecting portion 14B hold both ends of the sample 91. Further, the movable mechanism 13A is connected to the connecting portion, and the movable mechanism 13B is connected to the connecting portion. The movable mechanism (13A, 13B) enables the entire sample 91 to move in the longitudinal direction, that is, the vertical direction. Further, the movable mechanism (13A, 13B) can apply tensile or compressive stress to the sample 91 in the longitudinal direction, that is, the vertical direction.

  When applying the stress, the movable mechanism (13A, 13B), for example, fixes one of the connecting portion 14A and the connecting portion 14B and moves the other in the vertical axis direction with a motor (especially a servo motor is preferable). The sample strength test apparatus measures the relationship between the elongation of the sample 91 and the applied stress when tension is performed between the connection portion 14A and the connection portion 14B. Alternatively, the sample strength test apparatus records the elongation and the applied stress at the moment when the sample 91 is broken. As the recording means, for example, a load cell is used. The load cell is a strain gauge type force detector. The load cell uses a proportional relationship between stress and strain output by attaching a strain gauge to an elastic body called a strain body.

  The load cell changes the moving distance of the connecting portion 14A and the connecting portion 14B into an electric signal, and records this electromagnetically or mechanically as the amount of elongation of the sample 91. The sample strength testing apparatus performs operation control of the movable mechanism (13A, 13B), measurement of the moving distance of the connecting portion (14A, 14B), and stress calculation by a microcontroller (not shown).

  If the microcontroller moves the connecting portion 14A and the connecting portion 14B away from each other, a tensile test of the sample 91 is performed, and if the connecting portion 14A and the connecting portion 14B are moved closer to each other, a compression test of the sample 91 is performed. .

  The temperature control unit 12 includes a temperature bath 31 through which the sample 91 penetrates, and controls the temperature in the temperature bath 31. The penetrating sample 91 is movable in the temperature tank 31 in the longitudinal direction. The temperature control unit 12 performs temperature control by appropriately combining, for example, a temperature sensor (not shown) such as a semiconductor sensor and a heater (not shown) such as a nichrome wire. The temperature controller 12 includes a microcontroller (not shown) that receives an electrical signal from the temperature sensor and controls the heater to a predetermined temperature. The temperature control unit 12 heats the sample 91 in the temperature bath 31 to a desired temperature using a microcontroller, a temperature sensor, and a heater.

  The temperature control unit 12 further includes a structure 32 that can introduce gas or liquid into the temperature bath 31 from the outside. For example, the temperature control unit 12 can control the temperature of the sample 91 by sending air controlled to a predetermined temperature through the structure 32. Further, the temperature control unit 12 can wet or dry the sample 91 by sending air controlled to a predetermined humidity through the structure 32. Furthermore, the temperature control unit 12 can corrode the sample 91 by flowing a corrosive gas or solution through the structure 32. Furthermore, the temperature controller 12 can also clean the sample 91 by flowing a degreasing organic solvent such as ethanol or acetone through the structure 32.

  FIG. 2 is a schematic configuration diagram illustrating the hydrogen charging unit 11. The hydrogen charging unit 11 has a water tank 21 through which a sample 91 penetrates. The water tank 21 can be a transparent container such as glass or acrylic. The water tank 21 has a structure in which the rubber packing 24 is in close contact with the sample 91 at the bottom thereof, so that liquid does not leak from the water tank 21. For this reason, it is not necessary to make the water tank 21 and the sample 91 contact | adhere completely. Furthermore, even if the sample 91 moves in the longitudinal direction, the water in the water tank 21 does not leak due to the elasticity of the rubber packing 24. For example, the water tank 21 is filled with water as the liquid 25. Since the sample 91 penetrates the water tank 21, the liquid 25 and the surface of the sample 91 are in contact with each other. The water tank 21 may have a circumscribed portion 22 that covers the surface of the sample 91 penetrating the inside. The circumscribed portion 22 has a large number of holes so that the liquid filled in the water tank 21 and the surface of the sample 91 can come into contact with each other.

  The hydrogen charging unit 11 further includes means 26 for filling the water tank 21 with the liquid 25 and discharging the liquid 25 from the water tank 21. The means 26 is, for example, a pump. By using the means 26, the sample strength test apparatus can automatically fill the liquid 25 in the water tank 21 and discharge it.

  The hydrogen charging unit 11 further includes means 23 for electrolyzing the liquid 25 to generate hydrogen. The hydrogen charging unit 11 generates hydrogen by electrolyzing the liquid 25 in the water tank 21 by means 23. The means 23 is, for example, a potentiostat / galvanostat. The potentiostat is a device that controls the current flowing between the sample electrode and the counter electrode so that the voltage between the sample electrode and the reference electrode becomes a set value. The galvanostat is a device that controls the current flowing from the sample electrode to the counter electrode of the electrochemical cell. The sample strength test apparatus uses the sample 91 as a cathode and causes a current to flow between the sample 91 and the liquid 25 using the means 23 to reduce hydrogen ions in water on the surface of the sample 91. The current value output from the potentiostat / galvanostat can be processed by a microcontroller to control the hydrogen generation amount to a desired value.

  The sample strength testing apparatus includes a hydrogen charging step in which hydrogen is charged by supplying hydrogen to a part of the longitudinal direction of the rod-shaped sample 91 (hydrogen exposed portion) in the hydrogen charging unit 11 and a movable mechanism (13A, 13B). A moving process for moving the hydrogen exposed part in the longitudinal direction of the sample 91 to the temperature control part 12, a heating process for heating the hydrogen exposed part of the sample 91 by the temperature control part 12, and a movable mechanism together with the heating process or after the heating process (13A, 13B) and a stress applying step for applying stress in the longitudinal direction of the sample 91.

  In the hydrogen charging step, the means 26 introduces the liquid 25 into the water tank 21 through which the sample 91 penetrates, and the process in which the surface of the sample 91 and the liquid 25 are brought into contact with each other and the means 23 generates hydrogen by electrolyzing the liquid 25. And the process of discharging the liquid 25 from the water tank 21 by the means 26 in order. In addition to performing hydrogen charging by electrolysis, there are a method of filling with hydrogen gas and a method of using a warm bath such as thiocyanate. Further, a cleaning process for cleaning the surface of the sample 91 may be performed between the hydrogen charging process and the heating process.

  The sample strength test apparatus can select each process and perform a test. Specifically, the sample strength test apparatus can perform only the stress applying step as reference data. In addition, the sample strength test apparatus can perform a stress applying process immediately after the hydrogen charging process. Further, after the hydrogen charging process, the sample strength test apparatus moves the hydrogen exposed part to the temperature control part 12 in the moving process, and holds it for 30 seconds at 30 ° C., 30 minutes at 200 ° C., and 0 second at room temperature in the heating process. Thereafter, a stress applying step can be performed.

  The sample strength test apparatus and the sample strength test method according to the present invention may perform the strength test by generating defects in the sample by a method other than hydrogen charging.

11: Hydrogen charging part 12: Temperature control part 13A, 13B: Movable mechanism 14A, 14B: Connection part 21: Water tank 22: Outer part 23: Means 24: Rubber packing 25: Liquid 26: Means 31: Temperature tank 32: Structure

Claims (9)

A rod-shaped sample penetrating the inside, and the sample has a water tank movable in the longitudinal direction, and a hydrogen charging portion for hydrogen-charging the sample in the water tank;
A temperature control unit that is disposed in the longitudinal direction of the sample, the sample penetrates the inside thereof, and the sample has a temperature bath movable in the longitudinal direction, and heats the sample in the temperature bath;
The sample is moved in the longitudinal direction so that a desired portion of the sample can be charged with hydrogen by the hydrogen charging unit, or the desired portion of the sample can be heated by the temperature control unit, and the sample is moved in the longitudinal direction of the sample. A movable mechanism that applies stress;
A sample strength testing apparatus comprising:   The sample strength test apparatus according to claim 1, wherein the water tank of the hydrogen charging unit has a structure in which a liquid in the water tank and a surface of the sample in the water tank are in contact with each other. The hydrogen charging unit is
The sample strength test apparatus according to claim 1 or 2, further comprising means for filling the water tank with a liquid and discharging the liquid from the water tank. The hydrogen charging unit is
4. The sample strength test apparatus according to claim 1, further comprising means for electrolyzing the liquid in the water tank to generate hydrogen.   5. The sample strength test apparatus according to claim 1, wherein the temperature control unit further has a structure capable of introducing a gas or a liquid from the outside into the temperature bath.   6. The sample strength test apparatus according to claim 1, wherein the hydrogen charging unit, the temperature control unit, and the movable mechanism are arranged so that a longitudinal direction of the sample is a gravity direction. A hydrogen charging step of hydrogen charging a part of the longitudinal direction of the rod-shaped sample;
Moving the hydrogen-exposed portion of the sample that has been hydrogen-charged in the hydrogen charging step to a position where heat treatment can be performed in the longitudinal direction of the sample; and
A heating step of heating the hydrogen exposed portion of the sample after the moving step;
A stress applying step for applying stress in the longitudinal direction of the sample together with the heating step or after the heating step;
A sample strength test method. The hydrogen charging step includes
Introducing a liquid into a water tank through which the sample passes, and bringing the sample surface into contact with the liquid;
Electrolyzing the liquid to generate hydrogen;
Discharging the liquid from the water tank;
The sample strength test method according to claim 7, wherein:   9. The sample strength test method according to claim 7, further comprising a cleaning step of cleaning the surface of the sample between the hydrogen charging step and the heating step.

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