JPS61259155A - Apparatus for measuring polarization characteristics - Google Patents

Abstract

PURPOSE:To make it possible to measure polarization characteristics in any direction, by providing an apparatus capable of pressurizing a solution and a value mechanism, which is opened by pressing a container receiving an electrolyte solution to a member to be measured, to the container. CONSTITUTION:After the oxide scale on the representative part of a member 12 to be measured was removed by a grinder, the ground part is finished to a mirror surface by buff polishing. Next, when a container 1 is pressed to the member 12 to be measured, a gap is generated between the inner wall surface of the container 1 and the conical body 9 pressed by a spring 8 and the pressurized electrolyte solution 2 supplied from a liquid sump 15 through a vinyl pipe 14 is contacted with the member 12 to be measured. At this time, because an O-ring 13 is closely contacted with the member 12 to be measured, the electrolyte solution 2 is not leaked from the part between the container 1 and the member 12 to be measured. Further, because the hydrogen gas 16 generated from the opposed electrode 3 is accumulated by a gas partition plate 6 during the measurement of polarization characteristics, the measurement of polarization characteristics does not become impossible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for measuring polarization characteristics of metal materials, and particularly to a polarization characteristic measuring apparatus suitable for measurement in an actual device.

[Conventional technology]

Boiler materials undergo material deterioration because they are used at high temperatures. For example, in ferritic steel materials used mainly for headers, large-diameter steel pipes such as main steam pipes, superheater pipes, and reheater pipes, during operation, areas of pearlite structure, bainite structure, agglomeration of carbides, etc. Material changes occur, and the tensile strength and creep strength gradually decrease. Additionally, in the austenitic steel material used for superheater tubes, carbide precipitation, agglomeration, and coarsening occur during operation, and sigma phase, an intermetallic compound of iron and chromium, precipitates. It acts in the same way as creep voids and promotes the creep phenomenon.

By the way, the above-mentioned material deterioration is due to operating temperature.

Since it is controlled by operating time or applied stress, in actual boilers, consideration is given to such material deterioration.
They are usually designed with a lifespan of 100,000 hours or more.

However, accidents often occur in which boiler heat exchanger tubes designed to have a lifespan of 100,000 hours or more burst or bulge after tens of thousands of hours. A possible cause of such an accident is that the actual operating temperature is higher than the design temperature due to uneven flow of combustion gas, a decrease in the amount of water vapor that is the internal fluid, etc. Therefore, in order to predict in advance the blowout or bulge accident of boiler heat transfer tubes, it is necessary to examine the degree of material deterioration over time. Also.

As the number of boilers that have been constructed for more than 100,000 hours has increased, it has become necessary to estimate the remaining life of boiler components that have been operated for more than 100,000 hours.

As mentioned above, material deterioration is mainly due to changes in the microscopic properties of the material. Recently, a method has been proposed for non-destructively quantitatively evaluating the material deterioration of actual machine parts by interpreting changes in the microscopic properties of the material as changes in polarization characteristics in an electrolyte solution (Japanese Patent Application No. 55-62368). This method is
The method compares the polarization characteristics measured in actual equipment components with the polarization characteristics of unused materials, and uses the difference to estimate material deterioration and remaining life5.If this method is applied, it is possible to remove the pipes inside the heat exchanger tube. This eliminates the need for the laborious and time-consuming work of directly observing the metal structure using a microscope.

FIG. 5 shows an example in which a conventional polarization characteristic measuring device is applied to a boiler large-diameter steel pipe. A method for measuring polarization characteristics will be explained with reference to the same figure.

First, a representative portion 19 of the member to be measured 120 is selected, and after removing oxide scale with a grinder, it is subjected to puff polishing to make the surface condition uniform. next.

A container 1 for immersing the polishing part 19 into the electrolyte solution 2 is fixed to the polishing part 19 . After that, the electrolyte solution 2 is poured into the container 1, the polished part 19 is used as one electrode,
The counter electrode 3 is immersed in the electrolyte solution 2, and the electrodes 19, 3 are connected to a DC power source (none of which are shown) via a lead wire 4, an ammeter, and a voltmeter. A voltage is then applied between the electrodes 19.3 and the current flowing through the electrolyte solution 2 is measured.

[Problem that the invention seeks to solve]

When downward measurements are possible, such as when measuring the upper part of a boiler large-diameter steel pipe, it is possible to measure polarization characteristics using an apparatus configuration as shown in FIG. 5. However, in actual boilers, downward measurements as shown in FIG. 5 are often not possible for members where material deterioration is a problem.

Also, the most careful attention should be paid to the tap welds between the header and the superheater tube. Since the superheater tube is suspended from the header by tap welding, in order to measure the polarization characteristics of this welded part or heat-affected zone, it is necessary to perform upward measurements.

It is impossible to apply the conventional polarization characteristic measuring device as shown in FIG. 5 to upward measurements.

In other words, in measuring polarization characteristics, it is necessary to fix a container to the member to be measured, contain an electrolyte solution in the container, and connect the member to be measured and the electrolyte solution. , which is difficult with the conventional devices described above. For example, even if the part to be measured and the electrolyte solution can be brought into contact using a sealed container that prevents the electrolyte solution from spilling, during the measurement of polarization characteristics, the gas generated from the counter electrode may come into contact with the part to be measured and the electrolyte solution. measurement of polarization properties is not possible.゛Again. Since an actual boiler is made up of a large number of heat transfer tubes, in order not to overlook the heat transfer tubes that have suffered the most material deterioration, it is necessary to measure the polarization characteristics of a large number of heat transfer tubes and to check for material deterioration. It is necessary to investigate the extent. When such a large number of measurements are required, with the conventional polarization characteristic measuring device shown in Figure 5, it is necessary to attach the container to the member to be measured and to remove it each time after measuring the polarization characteristics. Yes, it requires a lot of time and effort.

Furthermore, since the electrolyte solution in the container spills when the container is removed after measurement, the electrolyte solution can only be used for one measurement, which is very uneconomical.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to be able to measure polarization characteristics in any direction, and in particular to easily measure polarization characteristics in an upward direction, which has been difficult to measure with conventional devices. The object of the present invention is to provide a polarization characteristic measuring device that can measure polarization characteristics.

[Means for solving problems]

The present invention provides a device for pressurizing an electrolyte solution in a container for storing an electrolyte solution, and a valve mechanism that is opened by pressing the container against a member to be measured, or a valve mechanism that is opened by pressing the container against a member to be measured. It is characterized by the addition of a water-containing substance.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below based on illustrated embodiments.

〔Example〕

FIG. 1 is a sectional view of a polarization characteristic measuring device according to an embodiment of the present invention.

In the figure, a container 1 for containing an electrolyte solution 2 is made of a non-conductive material such as acrylic, and is connected to a liquid reservoir 15 by a vinyl pipe 14. This liquid reservoir 15 is placed at a higher position than the container 1 in order to pressurize the electrolyte solution 2 and further supply the electrolyte solution 2 to the container 1.

The counter electrode 3 is fixed to the container 1 by a counter electrode support plate 10, and is connected to a DC power source (not shown) via an ammeter and a voltmeter using a lead wire 4. Counter electrode 3 support plate 7
(described later), a gas partition plate 6 is fixed to the container 1,
The container 1 is provided with a gas vent hole 11 which can be opened and closed by a cap 5 just below the gas partition plate 6. A conical body 9 is pressed against the inner wall surface of the container 1 by a spring 8 attached to a support plate 7, and is configured to prevent the electrolyte solution 2 from leaking. Also, in container 1.

A Qljl tongue is provided to prevent the electrolyte solution 2 from leaking from the gap with the member to be measured 12, and the electrolyte solution 2
A liquid receiver 20 is provided to catch the liquid when it leaks.

The member to be measured 12 is connected to a DC power source (not shown) using a lead wire 4 via an ammeter and a voltmeter.

Next, regarding the case where the measuring device with the above configuration is applied to the upward measurement of the tap welding of the superheater header of an actual boiler,
This will be explained with reference to FIG.

First, the oxidized scale on a typical portion of the member to be measured 120 is removed using a grinder, and then, in order to make the surface condition uniform, it is finished to a mirror surface by puff polishing. Furthermore, in order to use the member to be measured 12 as one electrode, the member to be measured 12 is connected to a DC power source using the lead wire 4 via an ammeter and a voltmeter (both not shown).

Next, by pressing the container 1 against the member to be measured 12, a gap is created between the inner wall surface of the container 1 and the conical body 90, and the electrolyte solution 2 is supplied from the liquid reservoir 15 to the container 1 via the vinyl pipe 14. The solution 2 comes into contact with the member to be measured 12, and becomes in a state where the polarization characteristics can be measured. By placing the liquid reservoir 15 at a higher position than the container 1, the electrolyte solution 2 is pressurized and further the electrolyte solution 2 is supplied to the container 1. In addition.

Since the O-ring 13 and the member to be measured 12 are in close contact, the electrolyte solution 2 will not leak from between the container 1 and the member to be measured 20. Incidentally, an attempt was made to measure the polarization characteristics of a superheater header with a diameter of 600 m with the O-ring 13 having a diameter of 10 m, and good measurements were possible without any liquid leakage. When the diameter of the member to be measured 12 is small, the electrolyte solution 2 may leak from between the container 1 and the member to be measured 120. However, if a leak occurs, the leaked electrolyte solution 2 is poured into the liquid receiver 20. This liquid leakage does not interfere with the measurement of polarization characteristics at all and does not affect the polarization characteristics.

During polarization characteristic measurement 1 For example, when the electrolyte solution 2 is NaOH, hydrogen gas 16 is generated from the counter electrode 3, but since this hydrogen gas 16 is stored by the gas partition plate 6, hydrogen gas 16 is generated during the measurement. It does not come into contact with the member to be measured 12 and make it impossible to measure the polarization characteristics. Furthermore, if the inside of the gas partition plate 6 is filled with hydrogen gas 16 during polarization characteristic measurement, the cap 5 may be removed and the gas vented through the vent hole 11.

After measuring the polarization characteristics, when the container 1 is separated from the member to be measured 12, the conical body 9 is pressed against the inner wall surface of the container 1 by the spring 8, so that the electrolyte solution 2 does not spill from the container 1. Therefore, the electrolyte solution 2 can be used repeatedly and is therefore economical.

It goes without saying that the polarization characteristic measuring device according to this embodiment can perform measurements even when facing downward or facing up.

In addition, in the polarization characteristic measuring apparatus shown in FIGS. 1 and 2, the valve mechanism of the container 1 does not necessarily include the conical body 9 and the spring 8.
It is not necessary to consist of a ball 17 and a rubber 18 as shown in FIG.

The action and effect are the same. Furthermore, it goes without saying that the combination of the cone body 9 and the rubber 18 or the ball 17 and the spring 8 has the same function and effect.

FIG. 4 is a sectional view of a polarization characteristic measuring device according to another embodiment of the present invention. In the figure, reference numeral 1 denotes a container for containing an electrolyte solution 2, which is made of a relatively soft non-conductive material such as vinyl chloride, and the tip of the container 1 is used to store an electrolyte solution 2 on a member to be measured. A sponge (a water-containing substance) 12 is attached for contacting with.

Also.

The container 1 can be sealed with a cap 5 and is provided with an electrolyte solution replenishment port 23 for replenishing the electrolyte solution 2. By pressing the container 1 with a finger to reduce the volume inside the container 1, the inside of the container is pressurized and the electrolyte solution 2 is supplied to the sponge 21 through the tube 22, thereby making it possible to measure the polarization characteristics.

Further, the counter electrode 3 is fixed to the container 1 by a counter electrode support plate 1o, and is connected to a DC power source (not shown) using a lead wire 4 via an ammeter and a voltmeter. A liquid receiver 2o is attached to the container 1 to receive the electrolyte solution 2 spilled from the sponge 21. Note that the member to be measured 12 is connected to a DC power source (not shown) using a lead wire 4 via an ammeter and a voltmeter.

In this way, the polarization characteristic measuring device shown in FIG. 4 presses the container 1 with a finger to reduce the volume inside the container 1 and pressurize the inside of the container. Liquid reservoir 15 and vinyl vibe 14 in the polarization characteristic measuring device shown
becomes unnecessary. Also.

Since the electrolyte solution 2 is supplied to the sponge 21 through the tube 22, even if some gas, such as air or hydrogen gas, remains in the container 1, there is no problem in measuring the polarization characteristics.
The gas partition plate 6 in the polarization characteristic measuring apparatus shown in the figure and FIG. 2 is unnecessary.

In addition, in FIG. 4, the sponge 21 can be inserted into the tube 22 to effectively supply the electrolyte solution 2 to the part in contact with the member to be measured 12 by the capillary action of the sponge 210 in addition to supply by pressurization. It is possible.

〔Effect of the invention〕

As detailed above, according to the present invention, polarization characteristics can be measured in any direction, even though material deterioration is likely to occur, especially at the stub weld between the header and superheater tube of an actual boiler. One-polarization characteristic measurement can be easily performed even in locations where measurement is difficult because upward measurement is required. This makes it possible to apply electrochemical methods that can nondestructively estimate material deterioration and remaining life in almost all parts of plants used under high temperature and high pressure conditions, such as boilers. Its industrial value is great.

[Brief explanation of drawings]

1 and 2 show a polarization characteristic measuring device according to an embodiment of the present invention, FIG. 1 is a sectional view thereof, FIG. 2 is a diagram showing an example of use, and FIG. FIG. 4 is a sectional view showing another example of the valve mechanism. FIG. 4 is a diagram showing another embodiment of the present invention. FIG. 5 is a sectional view of a conventional polarization characteristic measuring device. 1... Container, 2... Electrolyte solution, 3...
... Counter electrode, 4... Lead wire, 5... Cap, 6... Gas partition plate. 7...Support plate, 8...Spring. 9... Cone, 10... Counter electrode support plate, 1
1... Gas vent hole, 12... Measured member, 13.
...0 ring, 14...vinyl pipe. 15...Liquid reservoir% 16...Gas, 17...
・Ball, 18...Rubber. 20...Liquid receiver, 21...Sponge, 22.
··tube.

Claims (5)

[Claims] (1) In an apparatus for measuring the polarization characteristics of a member to be measured, in which a container for accommodating an electrolyte solution is fixed to a member to be measured and an electrode provided in the container is used, the container for accommodating the electrolyte solution. An apparatus for measuring polarization characteristics, comprising: a valve mechanism that opens when the container is pressed against a member to be measured; and a device that enables pressurization of the electrolyte solution. (2) The device according to claim 1, wherein the container has a gas reservoir between the valve mechanism and the electrode for storing gas generated from the electrode. (3) The gas reservoir has at least one gas vent hole.
The apparatus according to claim 2, having at least one part. (4) In an apparatus for measuring polarization characteristics of a member to be measured by fixing a container for accommodating an electrolyte solution to a member to be measured and using an electrode provided in the container, a container for accommodating the electrolyte solution. A water-containing substance, such as a sponge, is added to the contact portion with the member to be measured, so that the electrolyte solution can come into contact with the member to be measured via this water-containing substance. A device for measuring polarization characteristics. (5) The device according to claim 4, wherein the container is made of a flexible material.