JPH07159295A - Method and apparatus for sampling surface layer of metallic material - Google Patents

Abstract

PURPOSE:To sample a material conveniently by previously shaping the electrode for electro-discharge machining according to a target shape to be cut out. CONSTITUTION:The profile at a recess in an electrode 1 is designed according to the shape of a material to be cut out so that a material having required shape can be cut out by single operation. For example, the electrode 1 is fixed to a rotary shaft 7 through a supporting member 2 with a curvature equal to the distance from the rotary shaft 7. Current is fed to a rotational power generator 3 having liquid-tight structure through a power cable 4 on the electrode side thus rotating the electrode supporting member 2 and the electrode 1 round the rotary shaft 7 in the rotational direction 6 of electrode. When a voltage is applied simultaneously between the electrode 1 and a structural member 101, electro-discharge machining is started at the gap between them. The voltage is fed back to the power supply and the current and voltage are controlled, thus cutting out a microvolume material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a mechanism of a device for collecting a minute member from the surface of a structural material such as a power plant, a shape of an electric discharge machining electrode, and a collecting device by utilizing the principle of electric discharge machining. The present invention relates to a method for evaluating the soundness of a plant structure and a method for repairing the plant structure using the method.

[0002]

2. Description of the Related Art A conventional technique for collecting a surface layer of a metal material is a U-shaped electric discharge machining electrode in a pre-cut groove as described in JP-A-63-231238. The material was to be taken by means of lowering and moving it parallel to the metal surface. The processing liquid was designed to fill the weir by providing a weir around the processing section.

Further, in the conventional technique for collecting the surface layer of another metal material, as described in JP-A-1-267433, a discharge electrode of a ring-shaped strip plate is used to remove the electrode. The material was to be collected by rotating. The working fluid was supplied to the working section by a separately provided working fluid supply mechanism.

[0004]

Of the above-mentioned conventional techniques,
In the type that moves the U-shaped electrode parallel to the metal surface,
It is necessary to cut two grooves in advance before machining by electric discharge machining, and it is necessary to create a weir that fills the machining fluid, and it takes time to prepare before entering electric discharge machining using U-shaped electrodes. At the same time, the processing cost increased.

Further, in the case of machining a portion which an operator cannot approach in an industrial plant or the like, it may be difficult to form a groove and install a weir before electric discharge machining.

Further, since the shape of the groove remaining after the sampling process has a steep step, when using the device after sampling, problems such as stress concentration may occur.

In the prior art method using a ring-shaped strip plate electrode, the electrode shape is thin so that the shape of the electrode is greatly changed due to wear, and normal processing may not be possible in the middle of processing.

Further, since the shape of the electrode is a strip plate and has no curvature, there is a problem that when the electrode enters the inside of the material to some extent, the groove of the portion to be cut does not match the shape of the electrode, which hinders continuous cutting. It was

Further, there is a problem that the amount of electrodes supplied to make up for the consumed portion is limited, and new electrodes cannot be continuously supplied until the processing is completed.

Further, in order to continue supplying the electrode, it is necessary to attach a mechanism for rotating the electrode, which causes a problem that the apparatus becomes large in size and the cost increases.

Further, taking out after cutting the sample is
Since the holding means is provided separately from the sampling device, the work is complicated and the cost is increased.

Further, in the sample collection by the above-mentioned two methods, since the holding of the sample becomes unstable at the final stage of the electric discharge machining, there is a problem that the electric discharge becomes unstable and the machining does not proceed so that the sample cannot be taken. .

The object of the present invention is to make a mold electrode for electric discharge machining in advance in a shape that fits the purpose of the portion to be sampled, and to simply and easily replace the electrode during the machining or supply a new portion. It is an object of the present invention to provide a method and a device which can be driven by a mechanism to easily collect a material having a shape suitable for a purpose.

Further, an object of the present invention is to integrate a holding mechanism for the material cut from the structure member with the sampling device so that the entire device can be integrated into one unit to facilitate the work and the cost can be reduced. It is in.

Another object of the present invention is to provide a device which can easily and inexpensively collect materials for a case where a structure is installed in water and remote processing is required. .

Another object of the present invention is to provide a method capable of preventing the soundness of the structure from being deteriorated as much as possible by improving the shape of the stress concentrating portion after the completion of the sampling process.

Another object of the present invention is to provide a method and an apparatus for collecting a minute amount of a sample for investigating the secular change of the structural material in order to maintain the soundness of the plant.

[0018]

In order to achieve the above-mentioned object, a thick-walled mold electrode preliminarily machined in accordance with an assumed shape of a sample to be sampled is used as an electric discharge machining electrode.

In order to achieve the above object, a mechanism for connecting an electrode holding jig to the central axis and rotating the electrode around the central axis is provided to drive the electrode. Further, in order to achieve the above object, the electric discharge machining electrode is provided with a curvature corresponding to the distance between the central axis for rotating the electrode and the electrode, thereby facilitating the penetration of the electrode into the metal material.

Further, as another electrode driving mechanism for achieving the above object, the mold electrode is held by sandwiching the mold electrode between a plurality of cylindrical members, and the electrode can be fed by rotating the cylindrical member. It is the one.

Further, in order to achieve the above object, the shape of the die electrode is elongated in the machining direction so that both ends of the die electrode are used for electric discharge machining.

Further, in order to achieve the above object, the surface of the member to be sampled is held in advance by using a small holding device integrated with the sampler.

Further, in order to achieve the above object, a surface pressing member is pressed against the surface of the member to be sampled in advance, and the member to be cut is sandwiched between the die electrode and the surface pressing member after the cutting of the member to be cut is completed. It was made possible.

Further, in order to achieve the above object, a support jig for fixing the sampling device body is attached to the surface layer site sampling device.

Further, in order to achieve the above object, a die electrode for electric discharge machining having a gentle curvature in its outer peripheral portion is used to perform die electric discharge machining of a material sampling mark of a structure. .

In order to achieve the above object, when it is necessary to process in water such as a reactor pressure vessel and a reactor internal structure of a light water reactor type nuclear power plant, water is used as a working fluid for electric discharge machining. It is intended to be used as it is.

Further, in order to achieve the above-mentioned object, the material of the site where the secular change of the plant structure is supposed to be collected is sampled by using a sampling device in a minute volume.

Further, in order to achieve the above-mentioned object, a waste meat portion for material sampling is prepared in advance in the structure of the plant.

[0029]

[Function] Determine the shape and size of the recess, which is the cross section of the electrode, according to the assumed shape of the sample to be sampled. By using a thick die electrode designed and machined so that it has a certain thickness, it is possible to continue machining without changing its cross-sectional shape even if the wall thickness decreases to some extent during electrical discharge machining. A sample having a desired shape can be collected in a single process without exchanging or supplying a new part.

Further, it comprises a rotation control mechanism for the rotating shaft, a supporting jig for connecting the rotating shaft and the electric discharge machining electrode, and an electric discharge machining electrode. If the electric discharge machining electrode is attached to the rotating shaft via the supporting jig, the rotating shaft is rotated. The electrode can be driven simply by rotating the shaft, and by performing electric discharge machining until the tip of the electrode reappears on the surface of the metal material, for example, it is possible to easily take a sample even when performing remote control. it can.

Since the electric discharge machining electrode is provided with a curvature corresponding to the miracle of the movement of the electrode due to the rotation of the central axis in advance, the shape of the electrode entering the metal material does not change when the central axis is rotated, and The material can be smoothly introduced from the surface to the inside, and stable electrical discharge machining for sampling can be performed.

The mold electrode can be easily held by sandwiching the mold electrode with a plurality of cylindrical members, and one of the cylindrical members is rotated by the rotational force transmitting means to move the electrode. By simply applying a rotational force to the cylindrical member, the electrode can be made to penetrate from the material surface to the inside, and sampling can be easily performed.

Further, the length of the electric discharge machining electrode in the machining progress direction is made long, the cross-sectional shape is made equal over the entire length thereof, and both two ends of the electrode can be used for machining. The electrode is driven to rotate and the material is cut out by electric discharge machining using one electrode end, and when the sample becomes unstable and the machining does not progress, the shaft rotation direction is reversed and the other end is used for the opposite. By processing from the side, the final cutting of the sample can be performed.

Further, a holding device for generating a magnetic force or a holding device having a suction cup is installed integrally with the minute volume holding device, and first, the holding device holds a portion to be sampled, and then the electrode is driven to remove the material. Once the sampling is started, the material being processed can be fixed and the sampled material can be taken out without providing an external special sampling device.

In addition, a surface pressing member is pressed against the surface of the member to be sampled in advance, and after the cutting of the member to be cut, the member to be cut is sandwiched between the mold electrode and the surface pressing member and then moved away from the structure. The collected material can be taken out without providing a holding device.

Further, if the supporting jig for fixing the main body of the sampling device attached to the main body of the sampling device is brought into close contact with the structural member before the start of the electric discharge machining, the supporting jig is fixed between the structural member and the sampling device during machining. Relative displacement does not occur, the gap between the electric discharge machining electrode and the workpiece is kept constant, and stable machining becomes possible.

Further, the shape of the stress concentration portion formed by collecting the material is obtained by performing the mold electric discharge machining of the material sampling trace of the structure by using the mold electrode for electric discharge machining having a gentle curvature in its outer peripheral portion. Can be improved.

Further, in the case of targeting things in water such as a reactor pressure vessel and a reactor internal structure of a light water reactor type nuclear power plant, if water is used as it is as a machining fluid for electric discharge machining, A sample can be collected without specially preparing a processing liquid supply means.

Also, by collecting a minute volume of material using the surface layer site sampling device and conducting a material strength test and a material analysis test using the sampled material, the function of the plant structure is hardly affected. In addition, the secular change of the plant structure material can be investigated, and the soundness of the plant can be evaluated.

In addition, if a waste meat portion for collecting material is prepared in advance in the structure of the plant and the material is collected from the waste meat portion by the surface layer portion sampling device after operating the plant for a certain period, the plant structure The health of the plant can be monitored without affecting the function of.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
Will be described. 1 and 2 are views for explaining a method and apparatus for collecting a surface layer portion by rotationally driving an electric discharge machining electrode, of which FIG. 1 shows before the start of collection and FIG. 2 shows the end of collection. The structure member 101 is the machining fluid 100.
Being immersed in. The electrode 1 is supported by the electrode supporting member 2, and the electrode supporting member 2 is connected to the rotating shaft 7 of the liquid-resistant structure rotational force generating device 3. Liquid resistant structure torque generator 3
Electric power is supplied to the electrode 1 using the electrode side power cable 4. A voltage can be applied to the structure member 101 by the structure-side power cable 105. Further, the liquid resistant structure rotational force generating device 3 is supported by a device supporting member 5. An electric current is supplied to the liquid-resistant structure rotational force generating device 3 via the electrode-side power cable 4 to rotate the electrode support member 2 and the electrode 1 in the electrode rotation direction 6 around the rotation shaft 7. At this time, at the same time, the electrode 1 and the structure member 10
If a voltage is applied between 1, electric discharge machining is started from the gap between the electrode 1 and the structure member 101. The rotation of the electrode support member rotating shaft 7 is controlled by feeding back the electric current and voltage of the electric discharge machining to the power source and controlling the waveforms of the electric current and voltage appropriately. When the electrode 1 is rotated to the position shown in FIG. 2, the micro volume sampling material 102 is sampled. 1 and 2
The electrode 1 used in the embodiment described in FIG.
And FIG. 4 will be described. FIG. 3 is a view of the electrode viewed from the side, and the moving direction of the electrode is parallel to the paper surface. FIG. 4 is a view of the electrode as viewed from the front, and the moving direction of the electrode is perpendicular to the paper surface. The electrode 1 is attached to the rotating shaft 7 via the electrode supporting member 2. The electrode 1 has a curvature equal to the distance from the rotation axis 7 as seen from the side. Further, the electrode 1 has the same cross-sectional shape as seen in the front view, regardless of the position where it is cut. Therefore, when the rotating shaft 7 is rotated to allow the electrode 1 to enter the material, the cross-sectional shape of the cut portion does not change even if the electrode 1 is continuously inserted. Therefore, the electric discharge machining site is limited to the tip of the electrode 1, and the material can be collected by stable electric discharge machining with a small machining resistance. Further, the cross section of the electrode 1 has a shape with a depressed center, but this shape can be designed as necessary.
That is, if the shape of the recess of the electrode 1 is designed and manufactured in accordance with the required shape of the material to be collected, the material having the necessary shape can be collected by a single sampling process, and the shape of the trace of collection is also required. Can be designed by

As another embodiment of the present invention, a method of driving an electrode by an electrode feeding mechanism different from the method of FIGS. 1 and 2 and collecting a material will be described with reference to FIG. The electrode 1 has a certain curvature. This electrode is sandwiched and fixed between the electrode supporting columnar member 10 and the electrode driving columnar member 14 attached to the columnar member supporting jig 11. The electrode supporting columnar member 10 and the electrode driving columnar member 14 are made of an insulating material. Wire 1
One of the windings 3 is wound around the electrode driving columnar member 14, and the other is wound around the wire winding device 12. The cylindrical member supporting jig 11 and the wire winding device 12 are fixed to the device supporting member 5, and the entire device is integrated. The entire device and the structure member 101 are
It is in a state of being immersed in the working fluid. When the wire 13 is wound by the wire winding device 12, the electrode driving columnar member 14 rotates and the electrode 1 can be sent out.
When a voltage is applied between the electrode side power cable 4 and the structure side power cable 105 to bring the electrode 1 closer to the structure member 101, electric discharge machining starts. By further rotating the wire winding device 12 and continuing to feed the electrode 1, the cutting of the surface layer portion of the structure member 101 proceeds. For example, if the method of the embodiment of FIGS. 1 and 2 is used when it is desired to collect the surface layer portion using the electrode 1 having a small curvature, it is necessary to increase the distance between the rotating shaft 7 and the electrode, and It gets bigger. According to the method shown in FIG. 5, it is not necessary to enlarge the device even when the curvature of the electrode 1 is large.

In the surface layer portion sampling method according to the above-mentioned embodiment, when the machining progresses and approaches the final state of cutting, the fixation of the sampled material may become unstable and the electric discharge machining may not proceed. An embodiment considering such a case will be described with reference to FIGS. 6, 7, and 8. 6 shows the process at the start of machining, FIG. 7 shows the stage when the electric discharge machining has stopped, and FIG. 8 shows the stage when the final cutting process is started. The electrode 1 is made longer so that the unused portion remains sufficiently rearward even if the electrode is consumed by processing. First, as shown in FIG. 6, the electrode 1 is rotated in the electrode forward rotation direction 20 to start electric discharge machining. The processing procedure at this time is the same as the processing method shown in FIGS. When the processing progresses to the position shown in FIG. 7 and does not proceed any further, the electrode forward rotation direction 20 is maintained in this state.
Stop processing. Next, the electrode reverse rotation direction 21 shown in FIG.
Then, the electrode 1 is rotated. The structure member 101 has a primary processed groove 106 and an unprocessed portion 107. When the end of the electrode 1 on the side opposite to the end machined first approaches the structure member 101, electric discharge machining is started. If the processing is continued as it is, all the unprocessed portions 107 are processed, and the minute volume sampling material 102 can be cut off.

Next, another embodiment according to the present invention will be described with reference to FIG. The structure of the device of this embodiment is almost the same as that of the above-mentioned embodiment, but a sampling device fixing shaft 150 and a sampling material holding shaft 151 are added to the device of this embodiment.
Before starting the sampling of the material, the tip of the sampling device fixing shaft 150 is brought into close contact with the structure member 101. At this time, a magnet or a suction cup is used in order to prevent the tip of the sampling device fixing shaft 150 from completely adhering to prevent it from moving. Next, the sampling material holding shaft 151 is extended and brought into close contact with the surface of the microvolume sampling material sampling position 160. At this time, a magnet or a suction cup is used so that the tip of the sampling material holding shaft 151 is completely in close contact with and does not move. When the sampling process is completed, the sampling material holding shaft 151 holds the minute volume sampling material 102, and the sampling device fixed shaft 15 is held.
0 is separated from the structure member 101, and the whole sampling device is moved to the outside of the working fluid as it is, and then the microvolume sampling material 102
Take up. According to the method of the present embodiment, the gap between the electrode 1 and the structure member 101 can be stably controlled during sampling processing, and the sampling material can be easily and reliably taken out.

Next, another embodiment of the present invention will be described with reference to FIGS. 10, 11 and 12. FIG. 10 shows the structure member 200 after material sampling, and FIG. 11 shows the surface shape repairing electrode 20.
1 and FIG. 12 shows the structure member 202 after the surface shape is repaired.
Is shown. Corners are seen in the structure member 200 after the material is collected, and the stress concentration is large when a load is applied. The surface shape repairing electrode 201 has a smooth curved surface for electrical discharge machining. When the surface stepped portion of the structure member 200 after the material is collected is processed by the surface shape repairing electrode 201, the structure member 202 after the surface shape repairing having a smooth curved surface is obtained. According to this embodiment, it is possible to repair the surface of the structure member after the material extraction, which is expected to increase the stress concentration, and to improve the shape into which the stress concentration is small.

Next, another embodiment of the present invention will be described with reference to FIGS. 13, 14 and 15. FIG. 13 shows the structure member 210 after material sampling, and FIG. 14 shows the heat-affected layer removing electrode 21.
2 and FIG. 15 shows the structure member 213 after the heat affected layer is removed.
Is shown. The residual heat-affected layer 211, which is formed under the influence of heat generated by electric discharge machining, is present in the structure member 210 after the material is collected. Since the residual heat-affected layer 211 is different from the original property of the structure member, it may cause a problem when the structure is continuously used after the material is collected, and therefore, it needs to be removed before the structure is reused. There is. The heat-affected layer-removing electrode 212 is formed in a shape that fits a processing mark on the structure member 210 after material sampling. The heat-affected layer-removing electrode 212 is brought close to the processing mark, and the discharge energy is smaller than the discharge energy at the time of material extraction, and is slowly and slightly processed. Structure member 2 after removal of the heat-affected layer
The heat-affected layer hardly remains in 13 and the soundness of the structure can be maintained.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 16 shows a method of applying the surface region sampling apparatus according to the present invention to a nuclear power plant.
The light water reactor pressure vessel 250 has the pressure vessel upper lid 251 removed and the reactor internal structure 252 and the light water reactor pressure vessel 2 are removed.
The inner wall of 50 may be inspected. When a small volume of material is to be sampled for inspecting the inner structure of the reactor internal structure 252 and the light water reactor pressure vessel 250, the sampling device support arm 256 is used by using the sampling device driving device 255 on the workbench 254. The sampling device 257 can be moved via the to collect the material at the intended location. At this time, since the reactor internal structure 252 is below the cooling water surface 253, the cooling water can be used as it is as the working liquid of the sampling device 257. According to the method of this embodiment, the material can be easily collected by the method of using the cooling water without taking out the reactor internal structure 252 to the outside.

Next, another embodiment of the present invention will be described with reference to FIGS.
This will be described using 8. FIG. 17 shows an example 300 of the current plant structure member, and FIG. 18 shows an example 301 of the structure member in consideration of material collection, in which the structure member of FIG. There is. When the plant structure member is inspected, the material of the material collecting waste meat portion 302 is sampled and used for the material inspection. According to the method of the present embodiment, the material can be inspected by collecting the minute volume material without impairing the function of the plant structure member.

[0049]

According to the present invention, a minute volume material can be collected by a simple mechanism in which the electrode rotating shaft is rotated to rotate the electrode. In addition, the minute volume material can be sampled by a simple mechanism that only controls the rotation speed of the cylindrical member. From the above, it is possible to easily collect a minute volume material, and it is possible to perform a highly accurate material inspection using a material of an actual plant.

Further, by thickening the electrode, providing a curvature, and appropriately designing the cross-sectional shape according to the purpose, there is no need to replace the electrode or supply a new part in the middle of processing. In addition, it is possible to stably collect a minute volume material having a required shape, and to collect the material simply, quickly and at low cost.

Further, by providing the mechanism for fixing the sampling device and the mechanism for fixing the sampling material, the relative shake between the sampling device and the structural member can be reduced, so that stable electric discharge machining can be realized. .

Since the collected material can be held by providing the collecting material fixing mechanism integrally with the collecting device, the material can be taken out easily and surely.

Further, since the method for repairing the stress concentration portion remaining in the structure member after the material is collected is provided, the reliability of the structure can be maintained even after the minute volume material is collected.

Further, by providing the means for collecting the material in the reactor internal structure of the light water type nuclear power plant while keeping the light water in the reactor, the radiation exposure amount during the material collecting work can be reduced.

Further, since the method for removing the residual heat-affected layer remaining on the structure member after the material is collected is provided, the reliability of the structure can be maintained even after the minute volume material is collected.

Further, since the plant structure member is provided with a waste portion in advance so that it can be provided for collecting the minute volume material, the plant by collecting the minute volume material without affecting the function of the plant structure. You can inspect the actual material.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a state before implementation of an embodiment according to the present invention.

FIG. 2 is an explanatory diagram showing a state after the end of the embodiment.

FIG. 3 is a side view of an electrode used in the examples of FIGS. 1 and 2.

FIG. 4 is a front view of an electrode used in the examples of FIGS. 1 and 2.

FIG. 5 is an explanatory view showing another embodiment according to the present invention.

FIG. 6 is an illustration of a first stage of carrying out the method for completely cutting out material.

FIG. 7 is an illustration of a second stage of carrying out the method for completely cutting out material.

FIG. 8 is an illustration of a third stage for carrying out the method for completely cutting out material.

FIG. 9 is an explanatory diagram showing functions added to the embodiments of FIGS.

FIG. 10 is a cross-sectional view of the structural member after completion of the example.

11 is a side view of an electrode for repairing the structural member of FIG.

12 is a cross-sectional view of the structural member showing a state after repairing the structural member of FIG. 10 using the electrode of FIG.

FIG. 13 is a cross-sectional view of the structural member after completion of the example.

FIG. 14 is a side view of an electrode for repairing the structural member of FIG.

FIG. 15 is a cross-sectional view of the structure member showing a state after the structure member of FIG. 13 is repaired using the electrode of FIG.

FIG. 16 is an explanatory diagram showing a method of applying the embodiment to a nuclear power plant.

FIG. 17 is a perspective view showing an example of a current plant structure member.

18 is a perspective view showing an example of a structure member obtained by adding the function of the present invention to the plant structure member of FIG.

[Explanation of reference numerals] 1 ... Electrode, 2 ... Electrode support member, 3 ... Liquid resistant structure rotational force generating device, 4 ... Electrode side power cable, 5 ... Device support member, 6
... electrode rotation direction, 7 ... rotation axis, 100 ... machining fluid, 101
... structure member, 105 ... structure side power cable.

Claims (12)

[Claims] 1. A shaft rotation control mechanism, a supporting jig for connecting the rotation shaft and an electric discharge machining electrode, and a boat shape having a curvature corresponding to a mounting distance from the rotation shaft and having an inner surface recessed. It is composed of an electric discharge machining electrode, and the electrode is connected to the rotating shaft through an electrode supporting jig, and the rotating shaft is rotated in an insulating liquid to rotate the electrode, and the surface of the metal material is internally discharged. A method for collecting a surface layer portion of a metal material, which comprises cutting in a part of the surface layer of the metal material by advancing the electrode by processing. 2. The cross-sectional shape according to claim 1, which is processed by designing the shape and dimensions of the recessed portion so that a material having a shape suitable for the purpose can be sampled, and the cross-sectional shape when the electrode is rotated. So that it does not change in the direction of rotation of the center of rotation of
An electric discharge machining electrode that can collect the material of the desired shape in one machining. 3. The electrode according to claim 1, wherein the length of the electrode in the rotation direction is long so that the rotation direction of the rotation shaft can be selected from two directions, counterclockwise and clockwise. A method for sampling the surface layer of a metal material that can be electro-discharge machined with both. 4. The mold electrode according to claim 1, wherein the mold electrode is held by sandwiching the mold electrode with a plurality of cylindrical members, and the mold electrode is fed by rotating the cylindrical member to servo-drive the mold electrode. An electrode holding drive mechanism capable of 5. The collection jig main body fixing support jig according to claim 1, wherein the collection device main body fixing support jig is attached to the structure member before the material is collected, A method for collecting a surface portion of a metal material that enables stable material collection. 6. When the material is sampled using the sampling device of claim 1, the surface of the sampling target member is held in advance by using a small holding device integrated with the sampling device, and electric discharge machining is performed. A method of taking out a member to be cut in a surface layer portion collecting apparatus for a metal material, which is capable of securely fixing a collecting member therein and taking out the collecting member after electric discharge machining. 7. When a material is sampled using the sampling device according to claim 1, a surface pressing member is previously pressed against the surface of the member to be sampled, and after cutting is completed, the member to be cut is cut by the die electrode and the surface pressing member. A method of taking out a member to be cut in a surface layer portion collecting apparatus for a metal material, which enables reliable collection of a member to be cut after electric discharge machining by sandwiching the member and moving it away from the structure while keeping the sandwiched state. 8. A die discharge of a material gathering trace of a structure using a die electrode for electric discharge machining having a gentle curvature on its outer periphery after the material is gathered by using the gathering device according to claim 1. A member finishing method after material extraction, which improves the shape of the stress concentration part formed by material extraction by processing. 9. After the material is sampled using the sampling device of claim 1, the electrical discharge machining electrode of the structure is used to finish the pattern electrical discharge machining of the material sampling mark of the structure. A member finishing method after material extraction, which is performed under processing conditions and removes an abnormal layer on the surface that was left as a cut mark when the material was sampled. 10. Discharging water when it is necessary to perform processing in water using the collection device according to claim 1 such as the reactor pressure vessel and reactor internals of a light water reactor type nuclear power plant. A material sampling method applicable to pressure vessels and reactor internals of a light water reactor type nuclear power plant that is used as it is as a processing fluid for processing. 11. A small part of the material of the plant structure is sampled by using the sampling device of claim 1, and the sampled material is subjected to various material inspections and material tests, and the secular change of the material of the plant structure is performed. A method for evaluating the soundness of a plant structure for evaluating. 12. A method according to claim 1, wherein the sampling device according to claim 1 is used.
In order to make it possible to easily apply the soundness evaluation method of the plant structure of No. 1, a structure in which a waste meat part for material sampling is prepared in advance.