JPH0713625B2 - Degradation detection method and device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a deterioration inspection method and apparatus, and particularly to a metal such as ferritic stainless steel used in a high temperature environment such as a chemical plant and a nuclear plant. The present invention relates to a measuring method and an apparatus suitable for detecting high temperature aging embrittlement damage in an actual material member.

[Conventional technology]

Examples of conventional embrittlement measuring methods include the methods described in JP-A-54-61981 and JP-A-61-28859. Among them, Japanese Patent Laid-Open No. 54-61981 discloses that the presence or absence of embrittlement of an austenitic stainless weld metal is judged by the fact that the amount of δ ferrite in the initial stage is decreased by 5% or more.

Japanese Unexamined Patent Publication No. 61-28859 proposes a method of detecting deterioration due to a change in magnetic characteristics of an object to be measured.

In addition to the above, the technique described in Japanese Patent Laid-Open No. 168545/1982 is used as a method for monitoring the tissue state by utilizing the magnetic properties of the object to be measured, and the technique disclosed in Japanese Patent Laid-Open No. 59-168545 is related to detection of the magnetic properties itself. The technologies described in Japanese Patent Publication No. 108970 have been proposed respectively.

[Problems to be solved by the invention]

In the prior art described in JP-A-54-61981, among the metal materials used at high temperature, especially when ferritic stainless steel is used as an example, aging embrittlement occurs when used at high temperature for a long time. Is already known. This is because at a relatively high temperature of about 600 ° C. or higher, σ embrittlement occurs due to the precipitation of the σ phase, and in the range of 400 ° C. to 500 ° C., so-called 475 ° C. brittleness occurs. But 4
75 ° C brittleness may occur during long-term use even in the temperature range of 400 ° C or lower, and it is necessary to give sufficient consideration to the use of actual equipment members of ferritic stainless steel at high temperatures.

However, the above-mentioned prior art does not consider brittleness at 500 ° C or lower, and cannot detect the degree of 475 ° C brittleness.

Further, the initial ferrite amount of the actual welded portion varies depending on the welding position, and the variation is large. Further, in the actual machine, since the number of welded parts is huge, it is difficult to monitor all the welded parts and the initial ferrite content of the equipment materials. That is,
Since the conventional technique cannot be applied to a portion where the initial ferrite amount is unknown, there is a problem that it cannot be put to practical use in an actual machine.

On the other hand, Eddy Current Test Method (ECT)
There is a technique described in Japanese Patent Laid-Open No. 55-141653. In this conventional example, the ECT value of the measured material and the measured object before use, or a material of the same kind of material as that is subjected to the same heat treatment as the initial heat treatment of the measured object, and the ECT value is compared, and the value is positive. It shows a method of judging the deterioration state of the iron-based alloy depending on whether it is negative or negative.

However, quantitative determination could not be performed because it was determined only by positive or negative.

In addition to this, in the technique proposed in Japanese Patent Laid-Open No. 61-28859, it is necessary to measure the initial value of the magnetic characteristics in advance.
The technology proposed by 8970 and 56-168545 cannot be applied to the deterioration detection, merely to measure the material properties.

An object of the present invention is to provide a method and an apparatus capable of nondestructively and accurately detecting the degree of embrittlement of an actual machine member made of a metallic material such as ferritic stainless steel used in a high temperature environment.

[Means for solving problems]

The above-mentioned object can determine the degree of deterioration of a material by measuring the magnetic characteristics of the material that change with the aging deterioration of the material. The form of magnetic hysteresis that can be mentioned as a representative example showing the magnetic characteristics of a material corresponds well to the degree of deterioration of the material. That is, the degree of deterioration of the object to be measured such as a metal material can be estimated from the change in the magnetic characteristics.
Moreover, the degree of deterioration of the metal material can be estimated with high correlation by statistical data processing such as multiple regression analysis.

In order to efficiently excite the object to be measured, it may be possible to employ a coil made of a superconducting material as the exciting coil.

Further, the magnetic field can be detected by using a magnetic sensor device of a superconducting quantum interference device or a semiconductor Hall device capable of highly accurate magnetic measurement instead of the detection coil and the integrator.

A first invention of the present application relates to a deterioration detecting method for applying a magnetic field to an object to be measured, monitoring a change in magnetic characteristic peculiar to the object to be measured, and knowing a degree of deterioration of the object to be measured from the change in magnetic characteristic. Of the parameters of the magnetic characteristics of the measured object that has been deteriorated from the relationship between the change and deterioration of the magnetic characteristics that have been obtained in advance for the measured object, the value of the magnetic parameter depending on the deterioration in the initial stage of the measured object is By using a calibration curve that is estimated with another magnetic parameter that does not depend on deterioration, the magnetic properties of the unused material of the measured object are estimated, and the change from the estimated magnetic properties to the magnetic properties at the time of detection is measured by the magnetic field. It is characterized in that it is output as the degree of deterioration from the relationship between characteristics and deterioration.

The second invention of the present application is based on the same premise as the above-mentioned first invention, and the magnetic hysteresis loop previously obtained by changing the magnetomotive force of the deteriorated measured object is regulated so that the entire size becomes one. It is converted or further processed to create a database to cancel the unused state, and the calibration curve based on this normalized magnetic characteristic data is used to compare the measured magnetic characteristic data with the measured magnetic characteristic data. It is characterized in that the degree of deterioration of the measured object at that time is estimated without the data of the initial state of the receiving material (untreated material).

Here, "to make the entire size one" means that the maximum value of the magnetic flux density in the hysteresis loop is set to 1 (normalized), and the factors that affect the initial value of the material such as the ferrite amount are Means to be removed. As a result, it is possible to cancel the variation in the initial state of the material to be measured, so that it is possible to read only the parameters that depend on the deterioration as the shape change of the deteriorated normalized hysteresis loop of the measured object to judge the deterioration. Further, "setting the maximum value to 1 (normalizing)" corresponds to determination example 4 described later.
The rationale for normalizing the maximum value to 1 is in the attachment. That is, in FIG. 14, the BH curve of the virgin material is made dimensionless with the BH curve of the deteriorated material. The B-H curve in Figures 17-21 is B
_PP (Saturation magnetism) Normalized by the maximum magnetic flux density. this is
By dividing by B _PP , each B-H curve has a maximum value of 1.

Also "Cancel (normalize) unused state"
As described above, it means that the magnetic parameter that changes in the initial stage of the measured object is set to 1 and the hysteresis loop of the measured object is normalized. If this normalized hysteresis loop is used, the deterioration can be estimated from the magnetic parameters of the normalized hysteresis loop by using the calibration curve in a state where the variation in the initial value is canceled.

A third invention of the present application is a means for applying a magnetic field to an object to be measured, a means for detecting a magnetic characteristic of the object to be measured, and a change in the magnetic characteristic caused on the object to be measured by applying the magnetic field. In a deterioration detection device comprising a calculation device that outputs the degree of deterioration of a measurement object, the calculation device includes a database of a relationship between a change in magnetic characteristics and deterioration that has been previously obtained for the measured object, From the database, of the parameters of the magnetic properties of the measured object that has undergone deterioration, by using a calibration curve that estimates the value of the deterioration-dependent magnetic parameter in the initial measured object with another deterioration-independent magnetic parameter, A first arithmetic processing unit that estimates the magnetic characteristics of an unused material of the object to be measured, and a change from the estimated magnetic characteristics to the detected magnetic characteristics as a degree of deterioration from the database. Characterized by comprising a second arithmetic processing unit for outputting Te. It should be noted that the apparatus for estimating the degree of deterioration by the normalized database corresponding to the second method invention also belongs to the present invention.

A fourth invention of the present application is a device for applying a magnetic field to a test piece taken from a part of an object to be measured, a magnetic measuring device for detecting magnetic characteristics of the test piece, and the magnetic field application to the test piece. In a deterioration evaluation device comprising a calculation device that outputs the degree of deterioration of the test piece from changes in magnetic characteristics,
The arithmetic unit is a database of relationships between changes in magnetic characteristics and deterioration obtained in advance for the test piece (measurement target), and parameters of the magnetic characteristics of the deteriorated test piece from the database. , By using a calibration curve for estimating the value of the deterioration-dependent magnetic parameter in the early stage of the measured object by using another deterioration-independent magnetic parameter, in the case where the test piece is assumed to be a part of an unused measured object, It is characterized by comprising a first arithmetic processing unit for estimating a magnetic characteristic, and a second arithmetic processing unit for outputting a change from the estimated magnetic characteristic to the detected magnetic characteristic as a degree of deterioration from the database. . It should be noted that the apparatus for estimating the degree of deterioration by the normalized database corresponding to the second method invention also belongs to the present invention.

A fifth invention of the present application is the superconducting quantum interference device according to the fourth invention, wherein the magnetic measuring device includes a superconducting coil as an exciting coil, and a differential type superconducting pickup coil is arranged in the center of the coil. The differential superconducting pickup coil is equipped with a magnetic sensor, a space into which the test piece can be inserted from the outside is provided, and the other part is enclosed in a waterproof insulation container. A device is additionally provided, and the degree of deterioration is evaluated based on the relationship between the magnetic properties and the deterioration of the test piece that has been obtained in advance and the magnetic properties at the time of detection. The second
The apparatus for estimating the deterioration degree by the normalized database corresponding to the second method invention also belongs to the present invention.

(Magnetic Field Applying Means) A typical magnetic field applying means is an exciting coil.

(Magnetic characteristic) A typical magnetic field characteristic is magnetic hysteresis characteristic.

For example, multiple regression analysis of the relationship between changes in multiple parameters of magnetic hysteresis and deterioration of the metal material, which are detected in advance, by detecting multiple parameters of the magnetic hysteresis loop (magnetic hysteresis loop area, residual magnetic flux density, saturation magnetization, etc.) It is effective to use a data processing arithmetic unit that determines the degree of deterioration of the measured object by statistical data processing such as.

Further, as another example, a plurality of parameters of the magnetic hysteresis loop (magnetic hysteresis loop area, residual magnetic flux density, saturation magnetization, etc.) are detected to normalize the variation of the state of the virgin material of the material, and the previously determined magnetic field is obtained. It is also effective to use a data processing arithmetic unit that determines the degree of deterioration of the object to be measured by data processing of the relationship between changes in a plurality of normalized parameters of hysteresis and deterioration of the metal material.

(Unused material) In the present specification, the unused material means an unused material of the material, that is, a virgin material and a receiving material. For example, the initial ferrite content is a guideline for the magnetic properties of unused materials (reception material, initial state).

(Auxiliary equipment) For example, a degaussing device is used. That is, a degaussing device for degaussing the measured body is provided, and a plurality of magnetic hysteresis loops are obtained by changing the exciting magnetic force to be excited after degaussing, and a plurality of parameters of the magnetic hysteresis loop (magnetic hysteresis loop area, residual magnetic flux density , Saturation magnetization, etc.), and it is effective to use a data processing arithmetic unit for determining the deterioration of the metal material due to this change.

Further, for example, a feedback control type excitation device can be cited. That is, it is desirable to provide a feedback control type excitation device that sets the maximum magnetic flux density of the magnetic hysteresis loop to be measured and feedback controls the exciting magnetomotive force with high accuracy to detect the magnetic hysteresis loop of the material.

(Calculation device) A typical example of a data processing calculation device suitable for use is a database that determines the correspondence between the form of the magnetic hysteresis loop and the degree of deterioration of the metal material, and positively defines the measured magnetic hysteresis loop of the measured object. It is a data processing arithmetic unit that determines the deterioration degree of the magnetic hysteresis loop of the database having the closest form as the deterioration degree of the measured object. More specifically, the measured magnetic hysteresis loop of the measured object is normalized by the database that is obtained by exciting the material of the measured object up to the saturation magnetization and the correspondence of the deterioration degree of the metal material. The data processing arithmetic unit determines the deterioration degree of the magnetic hysteresis loop of the database having the closest form as the deterioration degree of the measured object.

In addition, for example, a data processing arithmetic unit that detects the harmonic distortion component of the magnetic hysteresis loop by Fourier transform and determines the deterioration of the metal material from the change in the value of the harmonic distortion component is also effective.

(Indication of Deterioration) Although an indication of deterioration will be described in detail in the present specification, it is convenient to estimate a decrease in fracture toughness value due to, for example, a change in the structure of a metal material.

(Magnetic Sensor) As a magnetic sensor, a superconducting quantum interference device is optimal. For example, it is easy to use an excitation system and a sensor system using a superconducting quantum interference device for capturing a precise magnetic change in a magnetic sensor device.

[Action]

Generally, when a metal material is used in a high temperature environment for a long time, the internal structure of the metal material changes, and the strength of the metal material decreases. As is remarkable in ferritic stainless steels in particular, the strength decreases as the heat treatment time for high temperature aging increases.

As a result of various studies on embrittlement of metallic materials such as ferritic stainless steel by high temperature heating, the present inventors have found that with high temperature aging, electromagnetic characteristics such as electric resistivity ρ and magnetic permeability μ of metallic materials and hardness. The inventors have found that mechanical properties such as the sheath metal structure also change, and have reached the present invention. In particular, it was found that the high temperature aging embrittlement of the material and the change of the magnetization characteristics correspond well, and the measurement results of the accepting material (untreated material), the high temperature treated material and the magnetic hysteresis show that the measured object is It was found that there are changes in the area of the magnetic hysteresis loop (magnetic hysteresis loss), the residual magnetic flux density, and the like. That is, by utilizing this phenomenon, the degree of progress of embrittlement of a metal material such as ferritic stainless steel can be detected with good accuracy.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

(Overall System According to First Embodiment) FIG. 1 shows an example of a system configuration for implementing a deterioration inspection apparatus for metallic materials according to the present invention. In this figure, reference numeral 1 is an object to be measured such as equipment or piping used in a nuclear power plant or the like. 2 is the object to be measured 1
And 3 is a magnetic sensor system for detecting magnetism. Reference numeral 4 is a magnetization controller unit, 5 is a data processing unit, 6 is a deterioration degree calculation unit, 7 is a database, and 8 is a display unit. Reference numeral 9 is a scan drive device for the excitation system 2 and the magnetic sensor system 3, and 10 is a scan drive control device.

The excitation system 2 and the magnetic sensor system 3 are arranged on the surface of the DUT 1 so as to face each other. The scanning drive 9 for scanning the excitation system 2 and the magnetic sensor system 3 comprises:
It is connected to the scan drive controller 10 and receives control.

The excitation system 2 and the magnetic sensor system 3 are connected to the magnetization control unit 4 and are subjected to measurement and control of excitation and magnetic detection. The excitation and magnetism detection data are fetched by the magnetic controller unit 4 and the optimum magnetization state is set. This data is processed by the data processing unit 5 for each deterioration parameter. The data for each deterioration parameter processed by the data processing unit 5 is compared and calculated by the deterioration degree calculation unit 6 based on the database 7 of the material obtained in advance, and the deterioration degree of the DUT 1 is determined. It This result is displayed on the display unit 8
Is output to.

(Examples of Excitation System and Magnetic Sensor System) Details of the excitation system 2 and the magnetic sensor system 3 will be described below.
Shown in the figure. The excitation system 2 includes a waveform control oscillator 21 for controlling the waveform of the magnetizing current to be excited, an amplifier 22 for amplifying the waveform, and an exciting coil 23 for magnetizing the DUT 1. A signal of the magnetomotive force of the exciting coil 23 is output from the amplifier 22. This signal is taken into the magnetic controller unit 4. The magnetic flux B passing through the exciting coil 23 and the DUT 1 is detected by the magnetic sensor 31. The output of the magnetic sensor 31 is output via the converter 32 to the magnetic controller unit 4
Is taken into.

(Example of Magnetization Controller Unit) The details of the magnetization controller unit 4 are shown in FIG. The magnetization controller unit 4 includes a magnetization hysteresis loop synthesizer 40, a magnetic flux density input interface device 41, a magnetomotive force input interface device 42, and a magnetic characteristic output memory device 4
3. A reference value setting device 44 and a differential amplification control device 45.

The magnetomotive force of the excitation system 2 for exciting the DUT 1 is taken into the magnetic hysteresis loop synthesizer 40 via the magnetomotive force input interface 42. The output of the magnetic sensor system 3 including a Hall element for detecting the magnetic flux induced by the magnetomotive force, a detection coil, and an integrator is taken into the magnetic hysteresis loop synthesizer 40 via the magnetic flux density input interface transmitter 41. These data are combined by the magnetic hysteresis loop combiner 40 into a magnetic hysteresis loop. This magnetic hysteresis loop is compared with a condition preset in the reference value setting device 44, and the difference is amplified by the differential amplification control device 45 and fed back to the excitation system 2 to set the optimum excitation state. The data of the magnetic hysteresis loop at this time is output via the magnetic characteristic output memory device 43.

(Example of Scan Driving Device) An embodiment in which the details of the driving device 9 for scanning the excitation system 2 and the magnetic sensor system 3 in FIG. 1 are applied to a boiling water reactor will be described with reference to FIGS. 4 and 6. Explain.

FIG. 4 is a sectional view of a boiling water reactor. 600 is a containment vessel, 610 is a reactor pressure vessel, 611 is a control rod, 61
2 is the recirculation feed pump, 613 is the primary system piping, 614 is the core, 6
15 is reactor water. Above the reactor containment vessel 600 is a crane 620. The scan drive device 9 is suspended from the crane 620, and the scan drive device 9 is arranged on the inner wall of the reactor water 615 of the reactor pressure vessel 610. The scanning drive device 9 is connected to a control device 910 or the like arranged outside the reactor containment vessel 600 by a cable 900, and operates by remote control.

FIG. 6 shows an example of an X-Y scanning drive device for inspecting the inner wall of a reactor pressure vessel. The scanning drive device 9 includes a frame 891 having four columns, a suction cup 892 for fixing to the inner wall of the reactor pressure vessel 610, an X-axis motor 895 for moving the vacuum pump 893 and the frame 891 on the X-axis, It consists of a gearbox 896 and a drive shaft 898, a Y-axis motor 897 for moving on the Y-axis, an air cylinder 899 equipped with a gearbox, and a drive shaft 894. The excitation system 2 and the magnetic sensor system are provided at the tip of the air cylinder 899. 3 is equipped.

As another embodiment, an example applied to a piping system of a boiling water reactor will be described with reference to FIGS. 5, 7, and 8.

FIG. 5 is a sectional view of a boiling water reactor similar to FIG. The scanning drive device 9 is arranged in the primary system pipe 613. The investigation drive unit 9 is a cable 900 for the reactor containment vessel 6
It is connected to a control device 910 or the like arranged outside 00 and operates by remote control.

FIG. 7 shows the primary system piping 613. Austenitic stainless steel material such as SUS304 or SUS316L is used for the base material 630 of the pipe, and a welding rod such as SUS308 is used for the welded portion 631 of the pipe. Therefore, the welded portion 631 of the pipe has a two-phase metallographic state in which the austenite phase and the ferrite phase are mixed.

FIG. 8 is an example of a drive device for inspecting a nuclear reactor piping system.
The scan driving device 9 is composed of a fixed ring 810 that can be divided into two and a rotating ring 811 that can rotate in the circumferential direction of the primary system pipe 613. The fixed ring 810 includes an axial drive motor 820, a gear box 821, and position detecting encoders 826 and 827.
There is a set of axial movement mechanisms. The amount of movement in the axial direction is
It is detected by the 824 and the position detection encoders 826 and 827 and fed back to the axial movement mechanism. The rotating ring 811 is
It is held by a fixed ring 810 by a plurality of pulleys 825 and driven by a circumferential rotation motor 823 having a circumferential position detection function. A part of the rotating ring 811 has a head portion 850 equipped with the excitation system 2 and the magnetic sensor system 3. The drive motors 820 and 823, the encoders 826 and 827, and the head unit 850 are magnetically shielded so that magnetic noise does not affect the magnetic measurement.

(Explanation of Principle) The principle of operation of this embodiment will be described with reference to FIGS. 9, 10 and 11.

As shown in FIG. 9, when a metal material is used in a high temperature environment for a long time, the internal structure of the metal material is changed and the strength thereof is lowered. First
Figure 12 shows the results of a Charpy impact test for an aged material obtained by subjecting ferritic stainless steel to 475 ° C heat treatment. The strength decreases as the heat treatment time for high temperature aging increases.

As a result of various studies on the embrittlement of metallic materials such as ferritic stainless steel by high temperature heating, the inventors have found that with high temperature aging, electromagnetic characteristics such as electric resistivity ρ and permeability μ of metallic materials and hardness It was also found that the mechanical properties such as the pod and gold structure also change. In particular, as shown in FIGS. 10 and 11, it was found that the high temperature aging embrittlement of the material and the change of the magnetization characteristic correspond well. According to the measurement results of the magnetic hysteresis of the accepting material and the high temperature heat-treated material in Fig. 10 and Fig. 11, the area of the magnetic hysteresis loop (magnetic hysteresis loss) and the residual magnetic flux density change depending on the degree of embrittlement of the measured object. I found that. By utilizing this phenomenon, the degree of progress of embrittlement of a metal material such as ferritic stainless steel can be accurately detected.

(Example of Operation Procedure) Now, an example of the measurement operation of the present invention in the system configured as shown in FIGS. 1 to 8 will be described with reference to the flowchart of FIG.

Step 1: First, the drive unit 9 is arranged on the surface of the DUT 1 such as the reactor equipment and piping, and the drive unit 9 is set at the origin of the measurement system.

Step 2: Enter the inspection range.

Step 3: With the start of measurement, the driving device 9 moves to the measurement start point.

Step 4: Start measurement. Collect measurement data.

Step 5: During the measurement, the data is stored in the magnetization control unit 4.

Step 6: After the measurement is completed, the driving device 9 moves to the next measurement position.

Step 7: Determine whether the measuring device 9 has reached the final position.

If “No”, go to step 4, and if “Yes”, go to step 8 in the direction of ending the measurement.

Step 8: The measurement data is input from the magnetization control unit 4 to the data processing unit 5, processed, and transferred to the arithmetic unit 6.

Step 9: The measured data is processed by the statistical data processing method, and the degree of age embrittlement is judged using the database. The result is output to the external recording device and displayed on the display unit 8.

(Example of Data Processing) Details of the statistical data processing of step 9 in FIG. 13 will be described below with reference to the drawing.

In the case of ferritic stainless steel as a metal material, for example, the magnetic hysteresis loop due to deterioration of high temperature aging,
It changes as shown in Figs. FIG. 10 is a magnetic flux density (B) -magnetomotive force (H) characteristic diagram for the receiving material, and FIG. 11 is a BH characteristic diagram after heat treatment at 475 ° C./443 hours.

This changing magnetic hysteresis loop is shown in Fig. 14 and
As shown in Fig. 15, the magnetic hysteresis loop area ratio and the residual magnetic flux density change depending on the magnitude of the magnetomotive force, and there is a clear difference between the deteriorated material and the virgin material in the region of the magnetomotive force above a certain value. However, the degree of material deterioration cannot be evaluated unless the initial ferrite content of the material can be estimated. FIG. 14 is a characteristic diagram showing the relationship between the super magnetic force and the magnetic hysteresis loop area ratio, and FIG. 15 is a characteristic diagram showing the relationship between the super magnetic force and the residual magnetic flux density, both of which are the receiving material (untreated material). Is shown in comparison with that after heat treatment. However, the maximum magnetic flux density due to the magnetomotive force shown in FIG. 16 hardly changes due to high temperature aging, but this maximum magnetic flux density is determined by the initial ferrite amount of the material. FIG. 16 is a characteristic diagram showing the relationship between magnetomotive force and magnetic flux density amplitude. For duplex stainless steel,
The initial magnetic properties of the material depend on the amount of ferrite. If the amount of ferrite doubles, the residual magnetism and the saturation magnetism also double. Therefore, the magnetic properties can be estimated because the initial ferrite amount can be estimated by arranging the parameters that do not depend on the thermal aging but only on the ferrite amount. Since the magnetic flux density amplitude in a high magnetic field does not depend on thermal aging as in the example shown in FIG. 16, the initial magnetic characteristics can be estimated from this parameter.

FIG. 17 is a characteristic diagram showing the relationship between the magnetomotive force and the normalized magnetic hysteresis loop, and FIG. 18 is a characteristic diagram showing the relationship between the magnetomotive force and the normalized residual magnetic flux density. 16 to 18 show a comparison between the receiving material and the member after heat treatment. As shown in Figs. 16 and 17, in order to correct the variation in the initial ferrite amount of the material, the deterioration of the material is evaluated by the normalized magnetic hysteresis loop area ratio normalized by the maximum magnetic flux density and the normalized residual magnetic flux density. It is effective to do. Here, “normalized data of magnetic hysteresis loop”
Is the normalized magnetic hysteresis loop data in which there is one parameter that can correct the variation in the initial state without depending on the deterioration in the magnetic hysteresis loop. Regarding the thermal aging of duplex stainless steel, the saturated magnetic Alternatively, it is for normalizing the magnetic flux density in a high magnetic field. In order to correct the amount of ferrite in the initial stage, normalization with the maximum magnetic flux density (saturation magnetism or magnetic flux density in a high magnetic field) that does not depend on thermal aging makes it possible to evaluate any deteriorated material with one calibration curve.

That is, as shown in FIG. 19, in the measurement and data collection (step 4), the measurement body is demagnetized, the magnetic hysteresis loop is obtained from the one having the smaller magnetomotive force, and necessary data is collected. The degree of deterioration of the collected data is determined by the master curve and the evaluation function which are obtained in advance in the data processing (step 9).

Thus, the magnetic hysteresis loop is obtained by continuously or discretely changing the magnetomotive force of the material of the measured object, and the normalized magnetic hysteresis loop area and residual magnetic flux density are arranged in FIGS. 17 and 18. Databases are prepared in advance for many steel types using the data of (1) as a calibration curve, and the degree of deterioration is estimated by comparing this database with the measured data without the initial data of the measured object.

(Second Example of Judgment Method) As another embodiment of the judgment method, there is a method of exciting a deteriorated material with a prescribed magnetomotive force and estimating the deterioration degree from the value at that time.

As shown in Fig. 14 and Fig. 15, the magnetic hysteresis loop area ratio and the residual magnetic flux density change depending on the magnitude of the magnetomotive force, and it is clear between the deteriorated material and the virgin material in the area of the magnetomotive force above a certain value. There is a big difference. Therefore, the magnetomotive force is set to a value suitable for deterioration detection, and the magnetic hysteresis loop is obtained.
When each parameter such as the magnetic hysteresis loop area of this magnetic hysteresis loop, the residual magnetic flux density and the maximum magnetic flux density is arranged by the deterioration parameter indicating the deterioration degree (for example, P value on the Lalson-Miller side),
It becomes like FIG. 20 and FIG.

That is, the deterioration parameter P value is determined from the measured magnetic hysteresis loop area, the residual magnetic flux density and the maximum magnetic flux density, and the deterioration degree of the material can be estimated.
By constructing the data as a database as shown in Fig. 21, the degree of material deterioration can be estimated. For example, the fracture strength of a metal material can also be evaluated if a database is prepared in advance with the deterioration parameters of the material as the Charpy impact value or the fracture toughness value K _1C as shown in FIGS. 22 and 23.

(Third Example of Judgment Method) In addition to the method of setting the magnetomotive force to a constant value, there is a method of setting the magnetic flux density to a constant value as a method of obtaining the magnetic hysteresis loop. This is shown in FIG. Since the magnetic hysteresis loop is obtained by controlling the magnetomotive force with high accuracy while keeping the exciting magnetic flux density constant, it is possible to easily improve the reproducibility and accuracy of the measurement data.

(Fourth Example of Judgment Method) As another example of the judgment method, there is a method of estimating the deterioration degree of the material from the form (pattern) of the magnetic hysteresis loop.

As shown in FIGS. 10 and 11, the form (pattern) of the magnetic hysteresis loop corresponds to the deterioration of the material. Therefore, FIG. 25 shows a method of estimating the degree of deterioration from the magnetic hysteresis loop form.

In the measurement and data acquisition (step 4) of FIG. 25, the measurement object is demagnetized, and magnetization by a constant magnetomotive force or saturation magnetization is selected to obtain a magnetic hysteresis loop and necessary data is acquired. The collected data is subjected to data processing (step 9) to normalize the magnetic hysteresis loop, and pattern matching is performed with a database of reference magnetic hysteresis loops obtained in advance. As a result, the magnetic hysteresis loop closest to the measured magnetic hysteresis loop form is selected from the database, and the deterioration degree and fracture strength of the measured object are estimated from the deterioration degree of the magnetic hysteresis loop.

(Fifth Example of Judgment Method) An example of another judgment method is shown in FIG. In the data processing of FIG. 13 (step 9), the output waveform of the magnetic flux density when the sine wave is input to the magnetomotive force is obtained by the measured magnetic hysteresis loop, and the distortion of the waveform of this magnetic flux density is calculated by the Fourier transform. The degree of deterioration of the material is obtained from the database obtained by conversion and from the database obtained by statistical processing such as recovery analysis from the magnitude and phase difference of each harmonic component.

(Overall System According to Second Embodiment) Another embodiment is shown in FIG. FIG. 27 shows the measurement object as sample 11
It is an example in the case where it can be collected as. The small sample 11 is inserted into the exciting coil 23 and excited by the exciting power supply unit 20. The sample 11 is provided with a differential coil 310, and the output of the coil is integrated by the integrator 320 to obtain the magnetic flux. Thereafter, the same processing as in the embodiment of FIG. 1 is performed.

(Example Using Superconducting System) As another example, an example using a superconducting system for the excitation system 2 and the magnetic sensor system 3 is shown in FIGS. 28 to 30.

FIG. 28 shows that the object to be measured 1 is excited with a strong magnetic field by using a superconducting system for the exciting coil 23 to improve the detection accuracy. In the structure of this embodiment, a container 110 made of a non-magnetic material, which is filled with a cooling material 130 in order to maintain the superconducting state of the superconducting exciting coil 23, is arranged on the surface of the DUT 1, and the superconducting exciting coil is placed in the container 110. The coil 23 is located. Magnetic sensor that can operate at low temperature in the center of superconducting exciting coil 23
There are 31. The container 110 is insulated from the outside by a heat insulating material 120. The coolant 130 is recirculated and cooled by the cooling device 410. A magnetic shield 1 is provided outside the container 110 and the excitation coil 23.
00 and 110 are provided to optimize the external magnetic field and the exciting magnetic field. The excitation coil 23 and the magnetic sensor 31 are connected to the magnetized coin roller unit 4 by a connection cable 500.

According to this embodiment, a strong magnetic field can be obtained with a small exciting coil, so that local deterioration diagnosis evaluation can be performed.

The embodiment shown in FIG. 29 is a case where a superconducting quantum interference device (SQUID) 340 having high detection sensitivity is used as the magnetic sensor of the embodiment shown in FIG. A pickup coil 330 for a superconducting quantum interference device is arranged in the center of the exciting coil 23, and a superconducting quantum interference device 340 is arranged outside the magnetic shield 101 to measure magnetism.

According to this embodiment, the magnetic field can be detected with high sensitivity, so that the detection of material deterioration can be dramatically improved.

FIG. 30 shows an example in which the sample 11 can be collected. The superconducting excitation coil 23 is in a container 110 made of a non-magnetic material filled with a coolant 130 to maintain a superconducting state, and the container 110 is insulated from the outside by a heat insulating material 120. There are two holes in the center of the superconducting excitation coil 23, and the sample 11 can be inserted from the outside. A pickup coil 330 of a differential coil is arranged in the two holes where the superconducting excitation coil 23 is arranged so that a uniform magnetic field is formed in this region, and the magnetic field is measured by the magnetically shielded superconducting quantum interference device 340. To do. It is possible to detect only the change in the magnetic characteristics of the sample in which the sample 11 is inserted in one of the two holes and the reference sample 12 is inserted in the other.

According to this embodiment, since the change in the magnetic characteristics of the material can be detected with high accuracy, the strain of the magnetic field can be measured with high accuracy, and the accuracy of material deterioration evaluation can be improved.

〔The invention's effect〕

According to the present invention, since the degree of embrittlement of a metal material used at high temperature can be detected nondestructively and quickly, it is possible to prevent embrittlement damage in advance and improve the safety of an actual machine. it can.

[Brief description of drawings]

FIG. 1 is an overall system diagram showing an example of the deterioration detecting device according to the present invention, FIG. 2 is an internal configuration diagram of an excitation system and a magnetic sensor system in the system according to the example of FIG. 1, and FIG. 3 is also a magnetic controller. Unit internal configuration diagram, 4th
The figure is a sectional view of a boiling water reactor using the system of FIG. 1, FIG. 5 is a sectional view of a boiling water reactor showing an alternative of FIG. 4, and FIG. 6 is the example of FIG. FIG. 7 is a perspective view showing an example of an XY-scanning drive device for inspecting an inner wall of a reactor pressure vessel.
The figure is a partial cross-sectional perspective view of the primary piping in the example of FIG.
FIG. 8 is a perspective view of the drive unit for inspecting the reactor piping system,
Fig. 9 is an explanatory diagram of changes in the metallographic structure when the metal is exposed to high temperature for a long time, Fig. 10 is a characteristic diagram showing the relationship between the magnetic flux density of the receiving material and the magnetomotive force, and Fig. 11 is the metal member after heat treatment. FIG. 12 is a characteristic diagram showing the relationship between magnetic flux density and magnetomotive force, FIG. 12 is a characteristic diagram showing the relationship of Charpy absorbed energy residual ratio to the aging time of heat treatment of metal members, and FIG. 13 is the operation in the embodiment of FIG. Flow chart showing the procedure, FIG. 14 is a characteristic diagram showing the relationship between the magnetomotive force of the metal member and the magnetic hysteresis loop area ratio, FIG. 15 is a characteristic diagram showing the relationship between the magnetomotive force of the metal member and the residual magnetic flux density, FIG. 16 is a characteristic diagram showing the relationship between the magnetomotive force of the metal member and the magnetic flux density amplitude, FIG. 17 is a characteristic diagram showing the relationship between the magnetomotive force of the metal member and the normalized magnetic hysteresis loop area, and FIG. 18 is the metal. Magnetomotive force and normalized residual magnetic flux density when the magnetic flux density of the member is constant Characteristic diagram showing the relationship, 19
FIG. 20 is a flow chart of an example of a deterioration determination method of the present invention, FIG. 20 is a characteristic diagram showing a relationship between a normalized magnetic hysteresis loop area of a metal member and a deterioration parameter, and FIG. 21 is a normalized residual magnetic flux density of the metal member. Characteristic diagram showing the relationship with the deterioration parameter,
FIG. 22 is a characteristic diagram showing the relationship between the normalized residual air hysteresis loop area of the metal member and the Charpy impact value, and FIG. 23 is a characteristic diagram showing the relationship between the normalized residual magnetic flux density of the metal member and the Charpy impact value, FIG. 24 is a characteristic diagram showing the relationship between the magnetomotive force of the metal member and the hysteresis loop of the magnetic flux density, and FIG. 25 is a flow chart of the method for estimating the degree of deterioration from the magnetic hysteresis loop form as an embodiment of the present invention. 26 is a flow chart for obtaining the degree of deterioration from the magnetic hysteresis loop via Fourier transform, and FIG. 27 is an overall system diagram of the deterioration detecting apparatus according to the second embodiment of the present invention, FIGS. 28, 29 and FIG. 30 is a sectional view of a device when a superconducting system is used in another embodiment of the present invention. 1 ... Object to be measured, 2 ... Excitation system, 3 ... Magnetic sensor system, 4 ... Magnetization control unit, 5 ...
Data processing unit, 6 ... Arithmetic unit, 7 ... Database, 8 ... Display unit, 9 ... Driving device, 10 ...
… Drive control device, 11 …… Sample, 12 …… Reference sample, 20 ……
Excitation power supply unit, 21 ... Oscillator, 22 ... Amplifier, 23 ...
… Excitation coil, 31 …… Magnetic sensor, 32 …… Transducer, 40…
… Magnetic hysteresis loop synthesizer, 41 …… Magnetic flux density input interface, 42 …… Magnetomotive force input interface, 43 …… Magnetic characteristic output memory device, 44 …… Reference value setting device, 45 …… Differential amplification control device, 91 …… frame, 92
…… Sucker, 93 …… Vacuum pump, 94 …… Drive shaft, 95
...... X-axis motor, 96 ...... gearbox, 97 …… Y-axis motor, 98 …… drive shaft, 99 …… air cylinder with gearbox, 100 and 101 …… magnetic shield, 110 ……
Non-magnetic material container, 120 ... Insulation, 130 ... Coolant, 31
0 ... Differential detection coil, 320 ... Integrator, 330 pickup coil, 340 ... Superconducting quantum interference device, 400 ... Cooling pipe, 410 ... Cooling device, 500 ... Cable, 600 ... Reactor containment vessel , 610 …… Reactor pressure vessel, 611 …… Control rod, 612 …… Recirculation feed pump, 613 …… Primary system piping, 61
4 ... Reactor core, 615 ... Reactor water, 620 ... Crane, 630 ... Piping base material, 631 ... Pipe welding, 810 ... Dividable fixed ring, 811 ... Rotating ring, 820 ... … Drive motor,
820,821 …… gearbox, 824 …… roller, 825 …… pulley, 826 …… encoder, 827 …… position detection encoder, 850 …… head part, 891 …… frame, 892 …… sucker, 893 …… vacuum pump , 895 …… X-axis motor, 896 ……
Gearbox, 897 ... Y-axis motor, 898 ... Drive shaft, 899 ... Air cylinder with gearbox, 900 ...
... Cable, 910 ... Control device, i ... Current, B ... Magnetic flux density, H ... Magnetomotive force.

Front page continuation (72) Inventor Makoto Hayashi, Kochimachi Co., Ltd., 502, Kazunachi, Tsuchiura, Ibaraki Prefecture (72) Inventor, Tsubasa Shimizu, 502, Jintacho, Tsuchiura, Ibaraki (72) Inventor Kazuo Takaku 3-1-1, Saiwaicho, Hitachi City, Ibaraki Hitachi Ltd. Hitachi factory (56) Reference JP 62-223663 (JP, A) JP 60-147646 ( JP, A) JP 58-132659 (JP, A) JP 59-131160 (JP, A) JP 63-180851 (JP, A) JP 1-119756 (JP, A) 61-161659 (JP, U)

Claims (5)

[Claims] 1. A deterioration detecting method for applying a magnetic field to an object to be measured and monitoring a change in magnetic characteristic peculiar to the object to be measured, and detecting the degree of deterioration of the object to be measured from the change in the magnetic characteristic. From the relationship between the change in the magnetic properties and the deterioration previously obtained for the measurement object, among the parameters of the magnetic properties of the deteriorated measurement object, the values of the magnetic parameters depending on the deterioration in the initial measurement object are different from each other. By using a calibration curve that estimates magnetic parameters that are independent of degradation,
Deterioration characterized by estimating the magnetic characteristics of an unused material of the object to be measured and outputting the change from the estimated magnetic characteristics to the magnetic characteristics at the time of detection as the degree of deterioration from the relationship between the magnetic characteristics and the deterioration. Detection method. 2. A deterioration detection method for applying a magnetic field to an object to be measured and monitoring a change in magnetic characteristic peculiar to the object to be measured, and knowing the degree of deterioration of the object to be measured from the change in magnetic characteristic. The magnetic hysteresis loop obtained by changing the magnetomotive force of the measured object received is normalized so that the whole becomes one size, and the unused state is canceled, and based on this normalized magnetic characteristic data A deterioration detecting method, characterized in that the degree of deterioration of an object to be measured at the time of measurement is estimated from measured magnetic characteristic data by the calibration curve described above. 3. A means for applying a magnetic field to an object to be measured, a means for detecting a magnetic characteristic of the object to be measured, and a change in the magnetic characteristic generated in the object to be measured by applying the magnetic field, to measure the object to be measured. In a deterioration detection device comprising a calculation device for outputting the degree of deterioration, the calculation device is a database of the relationship between the change and deterioration of the magnetic characteristics previously obtained for the measured object, and from the database, Among the parameters of the magnetic characteristics of the measured object that has been deteriorated, by using a calibration curve for estimating the value of the deterioration-dependent magnetic parameter in the initial measured object with another magnetic parameter that does not depend on the deterioration, A first arithmetic processing unit for estimating magnetic characteristics of an unused material of a body, and a change from the estimated magnetic characteristics to the detected magnetic characteristics is output from the database as a degree of deterioration. Deterioration detecting apparatus characterized by comprising a second arithmetic processing unit. 4. A means for applying a magnetic field to a test piece taken from a part of an object to be measured, a magnetic measuring device for detecting the magnetic characteristic of the test piece, and a magnetic characteristic of the magnetic property generated in the test piece by applying the magnetic field. In a deterioration evaluation device comprising a calculation device that outputs the degree of deterioration of the test piece from the change, the calculation device is a database of the relationship between the change and deterioration of the magnetic characteristics previously obtained for the measured object. And, from the database, using a calibration curve for estimating the value of the deterioration-dependent magnetic parameter in the initial stage of the object to be measured among the parameters of the magnetic properties of the deteriorated test piece with another deterioration-independent magnetic parameter. Thus, the first arithmetic processing unit that estimates the magnetic characteristics when the test piece is assumed to be a part of an unused measured object, and the change from the estimated magnetic characteristics to the detected magnetic characteristics The deterioration evaluating device, characterized by comprising a second arithmetic processing unit for outputting as the degree of deterioration from the database. 5. The magnetic measuring device according to claim 4, wherein the magnetic measuring device includes a superconducting coil as an exciting coil, and a superconducting quantum interference device magnetic sensor in which a differential type superconducting pickup coil is arranged in the center of the coil. Inside the superconducting pickup coil is provided in a space where the test piece can be inserted from the outside, the other whole is enclosed in a waterproof type heat insulating container, and a cooling material circulation type superconducting system cooling device is additionally provided.
A deterioration evaluation device characterized in that the degree of deterioration is evaluated from the relationship between the magnetic characteristics and the deterioration of a test piece which has been obtained in advance and the magnetic characteristics at the time of detection.