JP7368780B2 - Hydrogen permeation test device - Google Patents

Description

The present invention relates to a hydrogen permeation test device.

Metal structures installed outdoors, such as infrastructure equipment, corrode when exposed to wind and rain. Hydrogen generated by the corrosion reaction causes brittle fracture (hydrogen embrittlement) when it penetrates into the metal.

The probability of rupture increases as the amount of hydrogen in the metal increases. Therefore, it is important to quantify the amount of hydrogen in metals. A hydrogen permeation test is known as a method for measuring the amount of hydrogen in metals.

A typical hydrogen permeation test is a method in which hydrogen is allowed to enter from one side (hydrogen intrusion side) of a flat steel material, and hydrogen is detected on the other side (hydrogen detection side) using an electrochemical method (for example, non-patent literature 1).

Toru Mizuryu, "Measurement of hydrogen penetration and permeation into steel using electrochemical method," Materials and Environment, 63, 3-9 (2014).

Conventional hydrogen permeation test devices are limited to measuring flat metals. It is thought that if the shape of the metal surface (the place where hydrogen penetrates) changes, the amount of hydrogen penetrating will also change. Therefore, the conventional hydrogen permeation test device that measures the amount of hydrogen penetrating into a flat metal has a problem in that it cannot accurately measure the amount of hydrogen penetrating into the metal material being tested.

The present invention has been made in view of this problem, and it is an object of the present invention to provide a hydrogen permeation test device that can measure the correct amount of hydrogen penetrating a metal material to be tested.

A hydrogen permeation test device according to one aspect of the present invention is a hydrogen permeation test device that measures the amount of hydrogen penetrating into a metal material, and includes a metal sample obtained by cutting a portion on the opposite side of the surface of the metal material to be tested. , a sample holder that holds the opposite side of the test object on the side of the cut surface, a hydrogen intrusion section that allows hydrogen to enter the surface of the test object, and a hydrogen detection section that detects the amount of hydrogen from the cut surface. The gist is that.

According to the present invention, it is possible to provide a hydrogen permeation test device that can measure the correct amount of hydrogen penetrating into a metal material to be tested.

1 is a diagram showing an example of a functional configuration of a hydrogen permeation test device according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing a hydrogen intrusion section, a sample holder, and a hydrogen detection section shown in FIG. 1. FIG. FIG. 2 is a diagram schematically showing a procedure for manufacturing a sample holder according to an embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing a connecting portion between a sample holder and a hydrogen detection section. FIG. 3 is a diagram for explaining a case where a metal sample is produced from a metal material having an asymmetric shape.

Embodiments of the present invention will be described below with reference to the drawings. The same reference numerals are given to the same parts in the plurality of drawings, and description thereof will not be repeated.

[Hydrogen permeation test device]
FIG. 1 is a diagram showing an example of the functional configuration of a hydrogen permeation test device according to an embodiment of the present invention. A hydrogen permeation test device 100 shown in FIG. 1 is a device that measures the amount of hydrogen penetrating into a metal material.

The hydrogen permeation test device 100 includes a hydrogen inlet section 10, a hydrogen detection section 20, a sample holder 30, a galvanostat 40, and a potentiostat 50. Note that the galvanostat 40 may be replaced with a potentiostat 50.

The hydrogen intrusion section 10 and the hydrogen detection section 20 face each other with the sample holder 30 in between, and each contains an electrolytic solution. For example, 0.1 to 2M NaOH is used as the electrolyte. The electrolytic solution is poured into the hydrogen inlet section 10 and the hydrogen detection section 20 through the liquid supply ports (not shown) in an amount (up to a height) that at least the ring-shaped counter electrode CE is immersed therein.

The CE of galvanostat 40 and potentiostat 50 are opposite poles. RE1 and RE2 are reference electrodes, and WE is a working electrode. The tips of the reference poles RE1 and RE2 are curved in a hook shape so as to approach the sample holder 30.

The operation of these electrodes is the same as a typical hydrogen permeation test device. Therefore, further explanation of each electrode will be omitted.

FIG. 2 is a diagram schematically showing the hydrogen intrusion section 10, the sample holder 30, and the hydrogen detection section 20. In FIG. 2, the direction in which the hydrogen intrusion section 10 and the hydrogen detection section 20 face each other is defined as x, the width direction of the sample holder 30 as y, and the height direction of the sample holder 30 as z.

An O-ring 41 is provided between the hydrogen entry section 10 and the sample holder 30. Further, an O-ring 42 is provided between the sample holder 30 and the hydrogen detection section 20. The hydrogen entry section 10, sample holder 30, and hydrogen detection section 20 are coupled by compressing O-rings 41 and 42 in the x direction.

The compressive force in the x direction is generated, for example, by providing flanges (not shown) on opposing surfaces of the hydrogen intrusion section 10 and the hydrogen detection section 20, and fixing both flanges to each other with screws. Alternatively, the two surfaces of the hydrogen intrusion section 10 and the hydrogen detection section 20 on the side opposite to the sample holder 30 may be sandwiched and compressed.

(sample holder)
FIG. 3 is a diagram schematically showing a manufacturing procedure of the sample holder 30 according to this embodiment. The sample holder 30 is manufactured in the order shown in FIGS. 3(a) to 3(c). The upper diagram in FIG. 3 is a diagram of the sample holder 30 viewed from the hydrogen entry section 10 in the x direction. The lower figure is a view seen from the x direction by tilting the upper figure in the x direction.

The metal sample S shown in FIG. 3 is an example in which the metal material to be tested is, for example, a reinforcing bar. Since the reinforcing bars are long members, they are cut in a direction perpendicular to the stretching direction. A metal sample S is obtained by cutting the opposite side of the surface of the metal material to be tested.

Note that if the metal material is not a long member and is within a predetermined size range, there is no need to cut a part in the stretching direction to shorten it. If the metal material is within a predetermined size range, the metal sample S is obtained by cutting the opposite side of the surface of the metal material to be tested.

The metal sample S shown in FIG. 3 is obtained by, for example, cutting a part of a reinforcing bar in the stretching direction and further cutting (cutting) it in half. Therefore, in the above figure, the metal sample S appears to be square, for example. In the figure below, the metal sample S appears to be, for example, a semicircle.

To create the sample holder 30, first, a metal sample S is prepared. When the metal material is, for example, a reinforcing bar, the metal sample S is a cylindrical metal material (reinforcing bar) that is partially cut in the stretching direction and then further cut in half in the stretching direction.

Next, place the metal sample S on a flat surface with the side cut in half facing down. Then, a circular mold 60, for example, is placed around the metal sample S, and a resin is poured between the mold 60 and the metal sample S to form the first resin layer 31. The resin is a resin that hardens at room temperature and is not particularly limited.

In this case, the thinner the first resin layer 31 is, the more preferable it is. In other words, the semicircular surface of the metal sample S is exposed as much as possible. Further, the surface of the metal sample S on the side of the hydrogen intrusion portion 10 remains a metal material. In other words, the surface shape of the metal sample S on the side of the hydrogen penetrating portion 10 is free.

As shown in the lower diagram of FIG. 3(b), the metal sample S is fixed between the first resin layer 31 and the second resin layer 32 with the cut surface exposed to the hydrogen detection unit 20 side. The cut surface of the metal sample S on the side of the hydrogen detection unit 20 may be plated with Ni, for example, for the purpose of facilitating detection of hydrogen.

Next, a circular mold 61 is placed on the outer periphery of the first resin layer 31, centering around the metal sample S from which the mold 60 has been removed and the first resin layer 31, and a square mold 62, for example, is placed outside of the circular mold 61. Then, resin is poured between the molds 61 and 62 to form the second resin layer 32. The thickness of the second resin layer 32 is made thicker than the first resin layer 31. In this way, by making the first resin layer 31 around the metal sample S thinner and increasing the thickness of the second resin layer 32 outside it, the influence of the resin on the measurement is reduced, and the strength is ensured and the partition is The sample holder 30 can function as a.

Next, the molds 61 and 62 are removed after waiting for the first resin layer 31 and the second resin layer 32 to harden. The sample holder 30 is now complete.

In this way, the sample holder 30 includes a first resin layer 31 that holds the metal sample S with the cut surface of the metal material exposed to the hydrogen detection section 20 side, and a resin that is thicker than the first resin layer 31. A second resin layer 32 surrounding the first resin layer 31 is provided. This makes it possible to measure the amount of hydrogen penetrating the surface of the metal material being tested.

The sample holder 30 cuts the metal sample S on the side of the hydrogen detection section 20 so that the contact area with the electrolyte increases, and leaves the side of the metal sample S on the side of the hydrogen entry section 10 in the shape of the metal material. Therefore, the reaction area of the electrolytic solution can be increased, making hydrogen detection easier. Furthermore, it is possible to measure the amount of hydrogen intrusion depending on the surface shape of the metal material.

Although FIG. 3 shows an example in which the metal sample S is a reinforcing bar of a long member that is cut into short pieces, the metal sample S is not limited to this example. If the metal material is, for example, a screw of a predetermined size, the metal sample S may be one obtained by cutting the opposite side of the surface of the metal material to be tested (for example, at the center of the axis of the screw).

FIG. 4 is a cross-sectional view schematically showing a connecting portion between the sample holder 30 and the hydrogen detection section 20. A hole 21 is formed in the hydrogen detection section 20 facing the cut surface of the metal sample S, so that the cut surface of the metal sample S reacts with an electrolytic solution (not shown) in the hydrogen detection section 20.

The sample holder 30 side of the hole 21 is cut to a diameter larger than that of the hole 21, and an O-ring 42 is fitted into the cut portion. Since the O-ring 42 is compressed in the x direction by a screw or the like (not shown), the electrolyte does not leak to the outside.

Note that, although an example is shown in which the O-ring 42 corresponds to the first resin layer 31 of the sample holder 30, the present invention is not limited to this example. The O-ring 42 may be placed in the second resin layer 32 portion.

As explained above, the hydrogen permeation test device 100 according to the present embodiment is a hydrogen permeation test device that measures the amount of hydrogen penetrating into a metal material, and cuts the opposite side of the surface of the metal material to be tested. a sample holder 30 that holds the metal sample S on the side of the cut surface opposite to the metal material; a hydrogen intrusion section 10 that allows hydrogen to enter the surface of the test object; A detection unit 20 is provided. Thereby, it is possible to provide a hydrogen permeation test device that can measure the correct amount of hydrogen penetrating into the metal material being tested.

In other words, since a metal sample having the surface shape of an actual metal material is used instead of hydrogen penetrating into a flat metal material, the amount of penetrating hydrogen can be accurately measured.

(metal material with asymmetric shape)
Although the metal materials in the above embodiments are symmetrical about the axis, such as reinforcing bars and screws, the present embodiments can also be applied to asymmetric metal materials.

FIG. 5 is a diagram for explaining a case in which a metal sample S2 is produced from a metal material of non-equilateral angle material. The non-equilateral angle material is a material having an L-shaped cross section with different lengths in the y direction and the x direction.

FIG. 5(a) shows a case where the surface of the metal material to be tested is the side α shown in the figure. In this case, the metal material is cut along the cutting line αS2. Then, the metal sample S2 is held by the first resin layer 31 so that the surface including the cut surface of the metal sample S2 is exposed.

FIG. 5(b) shows the case where the surface of the metal material to be tested is in the β range. In this case, the metal material is cut along the cutting line βS2. Then, the metal sample S2 is held by the first resin layer 31 so that the portion β is exposed to the hydrogen intrusion section 10 side and the cut surface along the cutting line βS2 is exposed to the hydrogen detection section 20 side.

In this way, the metal sample S2 is cut so that the surface area of the metal sample S2 on the cut side is maximized. As a result, the surface area on the side of the hydrogen detection section 20 is maximized, so that the hydrogen detection efficiency can be improved.

As explained above, the hydrogen permeation test device 100 according to the present embodiment does not use flat metals of the same metal composition in metal materials of various shapes used for metal structures. Therefore, since the amount of hydrogen penetrating is measured while maintaining the shape of the actual metal material, it is possible to accurately measure the amount of hydrogen penetrating in the actual environment.

Furthermore, the greater the amount of penetrating hydrogen, the higher the probability of rupture due to hydrogen embrittlement. By using the hydrogen permeation test device 100, maintenance and inspection of metal structures can be carried out using the amount of hydrogen intrusion as a guideline.

The present invention is not limited to the above-described embodiments, and can be modified within the scope of the gist. The hydrogen permeation test device 100 is not limited to the example shown in FIG. For example, the tips of the reference poles RE1 and RE2 do not need to be bent into a hook shape. Further, the hydrogen intrusion section 10 and the hydrogen detection section 20 do not need to face each other in the horizontal direction (x direction). In addition, although the sample holder 30 has a square outer shape, the sample holder 30 may have any shape such as a circle or a polygon.

Moreover, the metal material has been explained using steel materials such as reinforcing bars as an example. Steel is an alloy made by mixing metals such as iron, aluminum, and copper in specific proportions. Therefore, the present invention can be applied to general metal materials.

Thus, it goes without saying that the present invention includes various embodiments not described here. Therefore, the technical scope of the present invention is determined only by the matters specifying the invention in the claims that are reasonable from the above description.

10: Hydrogen intrusion section 20: Hydrogen detection section 30: Sample holder 31: First resin layer 32: Second resin layer 40: Galvanostat 50: Potentiostat 100: Hydrogen permeation test device S: Metal sample

Claims (2)

A hydrogen permeation test device for measuring the amount of hydrogen penetrating into metal materials,
a sample holder that holds a metal sample obtained by cutting a portion opposite to the surface of the metal material to be tested on the side of the surface where the opposite side was cut;
a hydrogen intrusion section that allows hydrogen to infiltrate into the surface of the test object;
a hydrogen detection unit that detects the amount of hydrogen from the cut surface ,
The sample holder is
a first resin layer that holds the metal sample with the cut surface exposed toward the hydrogen detection unit;
a second resin layer surrounding the first resin layer with a resin thicker than the first resin layer;
The second resin layer is a resin formed between a first mold placed around the outer periphery of the first resin layer and a second mold placed outside the first mold.
Hydrogen permeation test equipment. The metal sample is
The hydrogen permeation test device according to claim 1, wherein the metal sample is cut so that the surface area of the metal sample on the side of the cut surface is maximized.

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