JPH076950B2 - Device and method for detecting deterioration of metallic material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for inspecting a metal material for damage or deterioration, and particularly to a ferrite-containing system used in a high temperature environment of a nuclear plant or a chemical plant. The present invention relates to a measuring device suitable for detecting high temperature aging embrittlement, strain damage, etc. in an actual machine member made of a metallic material such as stainless steel or low alloy steel.

[Conventional technology]

As an example of a conventional embrittlement measuring method, there is a method described in JP-A-54-61981. Here, the presence or absence of embrittlement of the austenitic stainless weld metal is determined by the fact that the initial amount of δ-ferrite has decreased by 5% or more.

[Problems to be Solved by the Invention]

In the above conventional technology, among the metal materials used at high temperature,
In particular, it has been already known that aging embrittlement occurs when used at high temperature for a long time, especially when a ferrite-containing stainless steel is taken as an example. This is due to the precipitation of the σ phase at a relatively high temperature of about 600 ° C or higher. This is because σ embrittlement occurs and so-called 475 ° C embrittlement occurs in the range of 400 ° C to 500 ° C. However, 475 ° C brittleness may occur during long-term use even in the temperature range of 400 ° C or lower, and sufficient consideration must be given to the use of high-temperature ferrite-containing stainless steel actual machine parts at high temperatures.

However, the above-mentioned prior art does not consider strain aging when there is embrittlement at 500 ° C. or less and pre-strain, and the degree of 475 ° C. brittleness cannot be detected.

Further, the initial ferrite amount of the actual welded portion varies depending on the welding position, and the variation is large. Furthermore, in an actual machine, since the number of welding spots is enormous, it is difficult to monitor all the initial amounts of ferrite in all welds and equipment materials. Therefore, the conventional technique has a problem that it cannot be put to practical use in an actual machine because it cannot be applied to a portion where the initial ferrite amount is unknown.

On the other hand, Eddy Current Test Method (ECT)
There is "a method for determining the state of deterioration of a strong precipitation effect type iron-based alloy" described in JP-A-55-141653.
This conventional example, the ECT value of the measured material and the measured object before use,
Alternatively, a method of judging the deterioration state of the iron-based alloy by comparing the ECT value of the same heat-treated material as the initial heat treatment of the measured object and showing whether the value is positive or negative is shown. There is.

However, quantitative determination cannot be performed because the determination is based only on whether the sign is positive or negative. Moreover, no consideration is given to strain aging when there is prestrain.

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

[Means for Solving the Problems]

The above-mentioned object can determine the degree of material deterioration and strain damage by measuring the magnetic characteristics of the material that change with aging deterioration of the material. The form of magnetic hysteresis and the level of magnetic Barkhausen noise indicating the magnetic properties of the material correspond well to the degree of material deterioration and the degree of strain damage. That is, the degree of deterioration and strain damage of the metal material can be estimated from this change.

In order to efficiently excite the object to be measured in a local region with a strong magnetic field,
It is also possible to adopt a superconducting coil as the exciting coil.

In addition, a superconducting quantum interference device (SQUID) that enables highly accurate magnetic measurement instead of a detection coil and integrator for magnetic field detection
Alternatively, a magnetic sensor of a semiconductor Hall element can be used.

To estimate the degree of deterioration and damage of metallic materials, saturation magnetism,
High correlation can be obtained by adding statistical data processing such as multiple regression analysis to parameters such as remanence, coercive force, magnetic Barkhausen noise level, and material data.

The deterioration damage detection device of the present invention is a metal material inspection device that applies a magnetic field to a measurement object by an excitation coil or the like, and detects deterioration or damage from a change in magnetism caused in the measurement object thereby, wherein the measurement object is Saturation magnetism, remanence, coercive force,
It is equipped with a magnetic measurement device that detects magnetic properties such as Barkhausen noise, and an arithmetic unit that obtains the state of the magnetic field in the measurement region by a numerical analysis method. An arithmetic unit for determining the degree of strain damage or deterioration of a material from a database of the relationship between changes in magnetic characteristics and damage or deterioration of a metal material and a display device for outputting the data are further provided, and further, an exciting coil and a magnetic sensor are arranged in an array. The method is characterized in that a dummy exciting coil is provided in the outermost peripheral portion in order to ensure the uniformity of the magnetic field in the outermost peripheral portion. In this case, the directivity of the excitation coil and the magnetic sensor are alternately arranged in the orthogonal direction, and the superconducting quantum interference device (SQUID) sensor is used as the magnetic sensor to detect the magnetic anisotropy. The structure is preferable.

Further, it is preferable to integrate an exciting coil that excites the measuring body and a magnetic sensor that detects the magnetic characteristics of the measuring body. In addition, an exciting coil for exciting the measuring body and a magnetic sensor for detecting the magnetic characteristics of the measuring body are arranged so as to sandwich the measuring body, the leakage magnetic flux of the measuring body is measured, and the strain damage or deterioration of the material is determined, or the excitation is performed. It is also effective to make the coil into a horseshoe shape and detect the magnetic anisotropy of the measurement object to determine strain damage or deterioration of the material.

If the latter determination method is adopted, in order to measure the magnetic anisotropy, it is also an idea to rotate the horseshoe-shaped excitation coil and determine strain damage or deterioration from the directions and values of the maximum magnetism and the minimum magnetism.

The deterioration damage detection method of the present invention is a method for determining strain damage or deterioration from magnetic characteristics, assuming a certain strain amount for the measured B-H characteristic, and measuring from a database of aging at that strain amount. B-H characteristic closest to the B-H characteristic determined by selecting the B-H characteristic closest to the B-H characteristic, determining the aging time, and then, based on this aging time, the strain amount database at this aging time. −
Select the H characteristic, re-determine the amount of strain anew, repeat the above method based on the amount of strain, and finally determine the amount of strain and aging time that have converged to determine the strain damage or deterioration of the measurement object. As a method, or as a method of determining strain damage or deterioration from magnetic properties, a certain amount of strain is assumed for the measured Barkhausen noise spectrum, and the Barkhausen noise spectrum measured from the aging database for that strain amount is used. Select the closest Barkhausen noise spectrum, determine the aging time, and then, based on this aging time, find the Barkhausen noise spectrum closest to the Barkhausen noise spectrum measured from the strain amount database at this aging time. Select and re-determine the strain amount anew, based on the strain amount,
Similarly, the above method is repeated, and the finally converged strain amount and aging time are also characterized by determining strain damage and deterioration of the measurement object.

When measuring the magnetic characteristics of the wall of a reactor pressure vessel, etc., an exciting coil and a driving device for scanning the magnetic sensor are arranged on the inner wall and the outer wall respectively, and an exciting coil is provided on the inner wall, a magnetic sensor is provided on the outer wall, or a magnetic sensor is provided on the inner wall. , It is effective to place the exciting coil on the outer wall. When measuring the magnetic characteristics of the pipe, an exciting coil and a driving device for scanning the magnetic sensor are arranged inside and outside the pipe, and the exciting coil is placed inside the pipe.
It is effective to dispose a magnetic sensor outside the pipe, a magnetic sensor inside the pipe, and an exciting coil outside the pipe.

Furthermore, from the measured damage and deterioration data of the measured body and the database of the equipment of the measured body, it is possible to provide a function of predicting the future progress of the damage and deterioration of the measured body from the deterioration database, and the damage and deterioration of the measured body. The screen of the display device that displays the deterioration status is divided into multiple parts, and the measurement conditions and measured magnetic properties are displayed, the operating environment and material data of the equipment of the measuring object,
Equipped with a functional unit that displays judged damage and deterioration data, future damage damage and deterioration progress prediction, etc., can input and correct data with a mouse, keyboard, etc. as necessary, and can re-correct judgment and calculation It is also effective to do.

In the specification of the application, "aging" refers to a phenomenon that occurs over time at a certain temperature of a metal material. What occurs at room temperature is called room temperature aging or natural aging, and what occurs by heating is called high temperature aging or artificial aging (above, quoted from Iwanami Physics and Chemistry Dictionary). In the present specification, aging time means aging at a certain temperature. It means the time required, and the term "aging embrittlement" means a phenomenon in which a metal material becomes embrittled by aging.

[Action]

When a metal material is used for a long time in a high temperature environment, the internal structure of the metal material changes, and the strength of the metal material decreases. The Sharpy impact test results of the aging material of the ferritic stainless steel containing 475 ° C heat treatment show that the strength decreases as the heat treatment time of high temperature aging increases.

As a result of various studies on the brittleness of metallic materials such as ferrite-containing stainless steel by high temperature heating, the inventors have found that other phases are precipitated in the grain boundaries of the metal structure, carbides, S, and P due to high temperature aging. It has been found that the segregation of γ changes not only mechanical properties such as hardness and impact strength, but also electromagnetic properties such as electrical resistivity ρ and magnetic permeability μ. In particular, it has been found that the high temperature aging embrittlement of the material and the change of the magnetic property correspond well. According to the measurement results of the magnetic hysteresis of the receiving material and the high temperature heat-treated material, the area of the magnetic hysteresis loop (magnetic hysteresis loss), the residual magnetism, the coercive force, and the like change depending on the degree of embrittlement of the measured object. In addition, when measuring the magnetic Barkhausen noise generated when a metal material is excited, there is a difference in the components of the magnetic Barkhausen noise level between the receiving material and the high temperature heat-treated material.

Further, when a plastic strain due to working is applied to a metal material such as a ferritic stainless steel or a low alloy steel, the magnetic characteristics of the material change depending on the plastic strain amount. Furthermore, when pre-strained material was aged, the change in magnetic properties corresponding to the degree of strain aging was also obtained.

That is, by utilizing such a phenomenon, it is possible to accurately detect the progress of working strain and aging embrittlement of metal materials such as ferritic stainless steel and low alloy steel.

〔Example〕

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

The relationship between strain damage and aging deterioration of the metallic material of the measuring body 1 and the magnetic characteristics, which is the principle of the present invention, will be described with reference to the drawings.

FIG. 20 shows a magnetic hysteresis loop when a plastic strain is applied to a duplex stainless steel.
When plastic strain εp = 0% and εp = 2% are compared, the plastic hysteresis changes the shape of the magnetic hysteresis loop,
Increases in maximum magnetic flux density and residual magnetic flux density are observed. However, the coercive force has hardly changed.

FIG. 21 shows changes in residual magnetic flux density depending on the amount of plastic strain in the duplex stainless steel CF3M and CF8M materials. From the figure, as the plastic strain increases, the residual magnetic flux density becomes
Although it increases rapidly, the residual magnetic flux density tends to saturate as the plastic strain increases. The CF3M and CF8M materials have the same tendency of change in residual magnetic flux density due to the amount of plastic strain, but their absolute values are slightly different.

FIG. 22 shows the relationship between the amount of plastic strain and the coercive force of the above materials. From the figure, the coercive force shows an almost constant value regardless of the amount of plastic strain. That is, plastic strain does not affect the coercive force.

FIG. 23 shows the relationship between the amount of plastic strain and the maximum magnetic flux material density for the above materials. From the figure, a slight increase in the maximum magnetic flux density can be seen by giving plastic strain, but the maximum magnetic flux density shows a substantially constant value regardless of the plastic strain amount.

FIG. 24 shows the magnetic characteristics (B-H characteristics) in the direction parallel to the plastic strain application direction and the magnetic characteristics (B-H characteristics) in the orthogonal direction when the plastic strain is applied to the metal material. Due to plastic deformation, magnetic domains in the material are aligned in the plastic strain direction, and magnetic anisotropy occurs in the parallel and orthogonal directions. Therefore, the BH characteristic (Bε in the direction parallel to the plastic strain
The B-H characteristic (B⊥εp) in the direction orthogonal to p) decreases.

FIG. 25 shows magnetic anisotropy data organized by the relationship between the maximum magnetic flux density Bp, the residual magnetic flux density Br, and the strain amount ε. That is, the strain state can be determined from the magnetic characteristics in the direction orthogonal to the direction parallel to the plastic strain.

Using these characteristics as a database, strain damage of metallic materials can be determined.

Next, the relationship between the aging deterioration of a metal material and magnetism will be described with reference to the drawings.

FIG. 26 shows the change in shear energy absorbed by aging of duplex stainless steel. As the aging time increases, the Charpy absorbed energy decreases. Therefore, in order to measure this change nondestructively, the relationship between aging and magnetic properties was investigated. One example is shown in FIG. It can be seen that the maximum magnetic flux density is almost unchanged in the magnetic hysteresis loop of the aging material as compared with the magnetic hysteresis loop of the virgin material, but the residual magnetic flux density, coercive force and magnetic hysteresis loop area are increased.

Next, the magnetic characteristics (BH characteristics) of the virgin material and the aged material of the duplex stainless steel material when the plastic strain εp = 2% is given.
An example is shown in FIG. When the virgin materials with plastic strain εp = 0% and 2% are compared, the shape of the magnetic hysteresis loop changes due to the plastic strain, and the maximum magnetic flux density and the residual magnetic flux density increase. However, the coercive force has hardly changed. When this plastic strain εp = 2% material is aged, a change in the shape of the magnetic hysteresis loop is recognized by aging, and the magnetic hysteresis loop area, the residual magnetic flux density and the coercive force are increased, as in FIG. 27. But,
The maximum magnetic flux density has hardly changed. From this, it is considered that the effect of plastic strain on the magnetic properties and the effect of aging on the magnetic properties are due to different mechanisms. That is, since magnetic domains have anisotropy in the plastic strain direction due to plastic deformation, the magnetic permeability increases and the maximum magnetic flux density increases. In addition, it is considered that during aging, the rotational moment of the magnetic domain increases due to the precipitation of α'phase and G phase in the ferrite phase having magnetism, and the residual magnetic flux density and coercive force also increase.

Fig. 28 shows the change in coercive force due to plastic strain. In the virgin material, the coercive force is constant regardless of plastic strain. In the aged material, the coercive force increases as the plastic strain increases,
Tends to saturate. Also, the greater the aging time, the greater this tendency.

Figure 29 shows the data in Figure 28 arranged by aging time. From the figure, in the virgin material, the coercive force is almost constant regardless of the amount of plastic strain, but with respect to the logarithm of the aging time,
It showed a tendency to increase almost linearly. Plastic strain εp =
Below 0.2%, the effect of plastic strain is not observed. In the range of plastic strain εp = 0.2% to 2%, the larger the plastic strain, the larger the change in coercive force.
Further, when the plastic strain εp = 2% or more, the influence of the plastic strain tends to be saturated.

Figure 30 shows the change in residual magnetic flux density due to plastic strain.
The residual magnetic flux density increases with increasing plastic strain, but tends to saturate. Also, the greater the aging time, the greater this tendency.

Figure 31 shows the data in Figure 30 arranged by aging time. The figure shows that the residual magnetic flux density tends to increase almost linearly with the logarithm of the aging time. The larger the amount of plastic strain, the larger the residual magnetic flux density.

Figure 32 shows the change in the maximum magnetic flux density due to plastic strain.
The maximum magnetic flux density increased sharply by applying plastic strain, but showed a constant value regardless of the amount of plastic strain. Plastic strain εp = 0% In the test piece in which plastic strain was applied to the material, the maximum magnetic flux density increased by about 50%.
Moreover, almost no change in the maximum magnetic flux density due to aging was observed.

Figure 33 shows the data in Figure 32 arranged by aging time. It can be seen that the maximum magnetic flux density does not change depending on the aging time.

FIG. 34 shows a magnetic hysteresis loop when low strain alloy steel is subjected to plastic strain. When plastic strain εp = 0% and εp = 4% are compared, the shape of the magnetic hysteresis loop changes due to plastic strain, and increases in coercive force and residual magnetic flux density are observed. However, the maximum magnetic flux density has hardly changed.

The operation principle of the present invention will be described with reference to FIG.

When a metal material is used for a long time in a high temperature environment, the internal structure of the metal material changes, and the strength of the metal material decreases. Figure 34 shows the results of the Sharpy impact test of aging-treated stainless steel containing ferritic stainless steel at 475 ° C. The strength decreases as the heat treatment time for high temperature aging increases.

As a result of various studies on the brittleness of metallic materials such as ferrite-containing stainless steel by high temperature heating, the inventors have found that other phases are precipitated in the grain boundaries of the metal structure, carbides, S, and P due to high temperature aging. It has been found that the segregation of γ changes not only mechanical properties such as hardness and impact strength, but also electromagnetic properties such as electrical resistivity ρ and magnetic permeability μ. In particular, it has been found that the high temperature aging embrittlement of the material and the change of the magnetic property correspond well. According to the measurement results of the magnetic hysteresis of the receiving material and the high temperature heat-treated material, the area of the magnetic hysteresis loop (magnetic hysteresis loss), the residual magnetism, the coercive force, and the like change depending on the degree of embrittlement of the measured object. In addition, when measuring the magnetic Barkhausen noise generated when a metal material is excited, there is a difference in the components of the magnetic Barkhausen noise level between the receiving material and the high temperature heat-treated material.

Further, when a plastic strain due to working is applied to a metal material such as a ferritic stainless steel or a low alloy steel, the magnetic characteristics of the material change depending on the plastic strain amount. Furthermore, when pre-strained material was aged, the change in magnetic properties corresponding to the degree of strain aging was also obtained.

That is, by utilizing such a phenomenon, it is possible to accurately detect the progress of working strain and aging embrittlement of metal materials such as ferritic stainless steel and low alloy steel.

FIG. 35 shows changes in the amount of plastic strain and coercive force in low alloy steel. From the figure, the coercive force rapidly increases with increasing plastic strain, but the coercive force tends to saturate as the plastic strain increases. When this material is aged, the coercive force decreases, but it becomes a constant value regardless of the aging time.

FIG. 36 shows changes in the amount of plastic strain and residual magnetic flux density in low alloy steel. This is the same result as the coercive force in FIG.

FIG. 37 shows the change in the shearpy absorbed energy with aging of low alloy steel. The change in the Charpy absorbed energy with the increase of the aging time is small.

Therefore, in order to nondestructively measure changes in aging and plastic strain, the relationship between magnetic properties was investigated. One example is shown in FIGS. 38 and 39.

Fig. 38 shows the change in coercive force of low alloy steel with increasing aging time. In the virgin material, the plastic strain can be identified by the coercive force. If aging, plastic strain εp
= 1% or less can be determined, but plastic strain εp = 1%
With the above, the coercive force becomes a constant value.

FIG. 39 shows the change in residual magnetic flux density of low alloy steel with increasing aging time. In the virgin material, the plastic strain can be determined by the residual magnetic flux density. When there is aging, it is possible to judge whether the plastic strain εp = 0.2% or less or εp = 0.5% or more.

Thus, in duplex stainless steels and low alloy steels,
A close correlation was observed between plastic strain and aging and changes in magnetic properties.

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

FIG. 1 shows an example of a system configuration for implementing a deterioration inspection apparatus for metallic materials according to the present invention. In the figure, reference numeral 1 is a measuring object such as a device or a pipe used in a nuclear power plant or the like. Reference numeral 21 is an exciting coil for exciting the measuring body 1, and 22 is a magnetizing device for the exciting coil 21. Reference numeral 31 is a magnetic sensor for detecting the magnetism of the measuring object 1, and 32 is a controller of the magnetic sensor 31. 41
Is a drive device for the excitation coil 21 and the magnetic sensor 31, and 42 is a controller for the drive device 41. 51 is an excitation controller 22, a magnetic sensor controller 32, and a drive controller 42.
It is a magnetic computing device that inputs and analyzes data from.
52 is a magnetic database of the measuring object 1. Reference numeral 61 is a deterioration calculation device that determines the deterioration degree of the measurement object based on the data analyzed by the magnetic calculation device 51. Reference numeral 62 is a database showing the relationship between the magnetism of the measuring object 1 and the degree of deterioration. 71 is a display device for outputting the measurement result.

In the operation of the system of the present invention, first, the measuring body 1 is excited by the exciting coil 21, and the magnetic change at this time is detected by the magnetic sensor 31.
Detect with. Details of an embodiment of this sensor unit will be described with reference to FIGS. 2 to 8.

FIG. 2 shows a structure in which the exciting coil 210 is arranged inside the core 211 having the coaxial structure to excite the measuring body 1. A magnetic sensor 310 such as a Hall element or a detection coil is arranged on the central core, and detects a magnetic change of the measuring object 1.

FIG. 3 shows a magnetic sensor 310 such as a Hall element or a detection coil in the embodiment of FIG.
It is located on the opposite side of 10. The magnetic change of the measuring body 1 is detected by the leakage magnetic flux.

4 and 5 show a sensor for detecting the magnetic anisotropy of the measuring body 1. In FIG. 4, an exciting coil is wound around the horseshoe-shaped core 212 to excite the measuring object 1. The magnetic flux on the surface at this time is detected by the magnetic sensor 310. In FIG. 5, the magnetic sensor 310 in the embodiment of FIG. 4 is arranged on the opposite side of the exciting coil 210 with respect to the measuring body 1. The magnetic change of the measuring body 1 is detected from the leakage magnetic flux on the opposite side of the exciting coil 210.

An embodiment in which the exciting coil 21 and the magnetic sensor 31 are arrayed in order to improve the measurement efficiency is shown in FIGS. 6 and 7.

FIG. 6 shows an embodiment of a one-dimensional array type sensor unit. Exciting coils 213 and 214 whose magnetic measurement directions are orthogonal to each other
And magnetic sensors 313, 314 are arranged one-dimensionally, and a dummy excitation coil 215 for correcting disturbance due to diffusion of magnetism is provided at the end. By scanning this array type sensor, the magnetic characteristics of the measuring object 1 can be detected at high speed.

FIG. 7 shows an embodiment in which the one-dimensional array type sensor shown in FIG. 6 is expanded two-dimensionally. Exciting coils 213 and 214 and magnetic sensors 313 and 314 whose magnetic measurement directions are orthogonal to each other are two-dimensionally arranged, and a dummy exciting coil 215 for correcting disturbance due to diffusion of magnetism is provided on the outer peripheral portion. By scanning the two-dimensional array type sensor, the magnetic characteristics of the measuring object 1 can be detected at a higher speed.

Figure 8 shows a magnetic sensor with a superconducting quantum interference device (SQUID).
It is an example using a sensor.

By applying a SQUID sensor that is generally used for biological examinations, liquid He is injected into a cryostat 333 that can measure an external magnetic field, and the temperature at which the SQUID sensor 330 operates is maintained. The SQUID sensor 330 section is inside a magnetic shield 334 that blocks noise. Magnetic signal is pick-up coil 331
Detect with. The pick-up coil 331 is arranged such that elliptic coils are orthogonal to each other in order to detect magnetic anisotropy, and is adapted to detect a difference in magnetic anisotropy. 9 and 10 show another embodiment of the pick-up coil. FIG. 9 shows a secondary differential coil formed coaxially. The magnetic distribution can be detected with high accuracy. 10th
In the figure, two or more differential coils are arranged in parallel, and the magnetic distribution can be detected with high accuracy.

An embodiment in which the driving device 41 for scanning the exciting coil 21 and the magnetic sensor 31 in FIG. 1 is applied to a boiling water reactor will be described with reference to FIGS. 11 to 16.

FIG. 11 is a sectional view of a boiling water reactor. Reference numeral 610 is a reactor pressure vessel, 611 is a control rod, 612 is a control rod guide tube, 613 is an upper grid, 614 is a core support, and 615 is reactor water.
Above the reactor pressure vessel 610 is a crane 617. The drive device 41a is suspended from the crane 617 by a cable 900, and the drive device 41a is arranged on the inner wall of the reactor water 615 of the reactor pressure vessel 610. The drive unit 41a is connected to a monitor 618 or the like arranged outside the reactor pressure vessel 610 by a cable and operates by remote control.

In addition, the drive unit 41b is arranged on the outer wall of the reactor pressure vessel 610, and the drive unit 41b uses the rail 620 instead of the cable 900.
And move in orbit. The drive units 41a and 41b can be linked by remote control to inspect the reactor pressure vessel 610.

FIG. 12 is an example of a reactor pressure vessel inspection XY scanning type drive device. The driving device 41 is a frame having four columns.
891, a suction cup 892 for fixing to the wall of the reactor pressure vessel 610, a vacuum pump 893 and a motor 895 for moving the frame 891 on the X axis, a gear box 896 and a drive shaft 898 and for moving on the Y axis. It is composed of a motor 897, an air cylinder 899 having a gear box, and a drive shaft 894. An exciting coil 21 and a magnetic sensor 31 are provided at the tip of the air cylinder 899.

As another example, an example applied to a piping system of a boiling water reactor will be described with reference to FIGS. 13 and 14.

FIG. 13 is an example of a drive device for external inspection of the reactor piping system. The drive unit 41 includes a fixing ring 810 that can be divided into two and a pipe 6
It consists of a rotating ring 811 that is rotatable in 30 circumferential directions. The fixed ring 810 has three sets of axial movement mechanisms including a drive motor 820, a gear box 821, and a position detection encoder 827. The amount of movement in the axial direction is detected by the roller 824 and the encoder 826, and is fed back to the axial movement mechanism. The rotary ring 811 is held by the fixed ring 810 by a plurality of pulleys 825, and is driven by a rotary motor 823 having a circumferential position detection function. Head part equipped with the excitation system 2 and the magnetic sensor system 3 on a part of the rotary ring 811.
There is 850. Drive motors 820, 823, encoder 826,
827 and the head portion 850 are magnetically shielded so that magnetic noise does not affect the magnetic measurement.

FIG. 14 is an example of a drive device for inspecting the inside of the reactor piping system. The drive device 41 includes a drive system for moving in the pipe and a scanning system for scanning the sensor unit.

In the drive system, a stepping motor or the like 910 transmits the respective drive wheels via a timing belt 922. Allows the device to be moved within the pipe.

In the scanning system, the pulley 9 can be
It is transmitted to the shaft 923 via the 24,928 and the timing belt 926. The magnetic sensor unit at the tip of the shaft 923 is scanned. The magnetic sensor unit includes an exciting coil 21 and a magnetic sensor.
It is composed of 31 and is pressed against the measuring object by the air cylinder 931 or the like at the time of measurement.

It should be noted that the measurement method shown in FIGS. 3 and 5 can be realized by combining the driving devices shown in FIGS. 12 to 14.

As described above, the excitation coil 21, the magnetic sensor 31, and the drive device 41 can detect the magnetic characteristics of the measuring object 1 such as a nuclear power plant.

Next, two examples of the measuring method will be described.

The first method is to detect the magnetic characteristics of the measuring body 1 in the thickness direction. Increase the output of the exciting coil stepwise,
The degree of penetration of the magnetic flux in the depth direction is changed to measure the change in magnetic characteristics. The information in the depth direction is obtained from the difference between the two magnetic characteristic data. Also, the same can be obtained by changing the frequency of the exciting coil and changing the penetration depth to the magnetic field.

The second method is to detect the magnetic anisotropy of the measuring object 1. By using the exciting coil shown in FIG. 4 or FIG. 5, the magnetic characteristics at all angles of the measurement object can be measured, and the magnetic anisotropy can be determined from the directions of maximum sensitivity and minimum sensitivity and the angular distribution of magnetism.

In FIG. 1, the measurement data of the exciting coil 21, the magnetic sensor 31, and the driving device 41 are input to the magnetic computing device 51 via the controllers 22, 32 and 42, respectively.

FIG. 15 shows the details of the magnetic computing device 51.

The data of the exciting coil 21, the magnetic sensor 31, and the driving device 41 that measured the measuring object 1 are stored in the input memory 51 of the magnetic computing device 51.
Captured by 1. The measurement data of the input memory 511 is output to the magnetic data display device 512 to check the measurement state. Further, basic magnetic data of each material is fetched from the magnetic database 52.

After checking the measurement state and the measurement data, the magnetic field analysis arithmetic unit 513 analyzes the magnetic field. The analysis method is selected from the magnetic field analysis code 514.

From the result of the analysis of the magnetic field, the anisotropic data processing 517 for separating the anisotropic data of the magnetic characteristic and the depth direction data processing 516 for separating the data of the magnetic characteristic in the depth direction are described above. Is processed as follows.

These data are input to the deterioration calculation device.

FIG. 16 shows details of the deterioration calculation device 61.

The anisotropy of magnetic properties and the data in the depth direction obtained by the magnetic field analysis are stored in the memories 561 and 562, respectively.

Magnetic property anisotropy data preprocessed
Pre-processing for deterioration determination is performed by 563, and parameters are selected in the order of highest correlation. Similarly, with respect to the data in the magnetic depth direction, the magnetic depth data preprocessing 564 also performs preprocessing for deterioration determination, and the parameters are selected in the order of highest correlation. These deterioration parameters are taken into the deterioration judgment calculation process 565, and the deterioration degree of the measuring object 1 is judged.

Further, the deterioration determination database has the data shown in FIGS. 20 to 42.

An example of details of the strain aging deterioration determination of the deterioration determination calculation procedure 565 will be described with reference to FIGS. 40 and 41.

Some plastic strained and aged materials are shown in Figures 40 and 41.
Using the results shown in the figure, plastic strain and aging time can be quantitatively separated. For example, the measured residual magnetic flux density
Assuming that Br is 450 Oe, plastic strain 4
% Aging time 100hr, plastic strain 0.5% aging time 200hr
Alternatively, there may be various cases where the plastic strain is 0.2% and the aging time is 400 hours. Here, aging time 100h with 4% plastic strain
In the case of r, the coercive force Hc is 37 Oe from Fig. 49. Similarly,
When the plastic strain is 0.5% and the aging time is 200 hours, the coercive force Hc is 43.
Oe, plastic strain 0.2%, aging time 400hr, coercive force Hc
Is 54 Oe. Therefore, the residual magnetic flux density Br and the coercive force Hc
Depending on the size of the, the plastic strain and the aging time are separated. The amount of plastic strain and aging time of duplex stainless steel can be determined from the residual magnetic flux density and coercive force.

Examples of other determination methods are shown in FIGS. 17 and 18.

FIG. 17 is for judging the degree of deterioration of strain aging from the shape of the magnetic hysteresis loop.

Assuming the initial strain amount, the closest magnetic hysteresis loop is found from the degree of aging at that strain amount, and the aging time is determined.

Next, the closest magnetic hysteresis loop is found from the strain amounts at this aging time, and the strain amount is determined.

Further, assuming this strain amount, the same determination is performed to determine the converged strain amount and aging time.

Figure 18 shows the Barkhausen noise spectrum.
The same judgment method as in Fig. 17 is used.

In addition to determining the current state of deterioration from the obtained data and considering the operating conditions from the database of the equipment, for example, graphs of FIG. 26, 29, 30, 33, or 37 are displayed. By predicting the progress of deterioration in the future by interpolating or extrapolating.

With such a method, strain aging can be judged and the progress of future deterioration can be estimated.

FIG. 19 shows details of the display device 71.

The screen of the display device 71 is divided into four, and the magnetic inspection measurement status, equipment data, deterioration degree judgment status, and future deterioration degree prediction are displayed, and each condition can be selected and modified with the mouse 72 on the screen. it can.

According to these examples, the degree of strain aging can be determined with high accuracy from the change in the magnetic properties of the material, so that the deterioration evaluation of the material can be improved.

〔The invention's effect〕

According to the present invention, since the degree of embrittlement and the amount of plastic strain of a metal material used at high temperature can be detected nondestructively and quickly, it becomes possible to prevent damage to the equipment, and the safety of the actual machine. Can be increased.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention, FIG.
FIGS. 3, 4, and 5 are side views showing details of the magnetic sensor unit, FIGS. 6 and 7 are perspective views showing details of the array-type magnetic sensor, and FIG. SQUID for magnetic sensor
Sectional views showing examples of sensors, FIGS. 9 and 10 are perspective views showing examples of pick-up coils of SQUID sensors, and FIG. 11 is a sectional view when the present invention is applied to a reactor inspection device. Schematic diagram, FIG. 12 is a perspective view of the XY scanning drive device used in the example of FIG. 11, FIG. 13 is a partial perspective view of the pipe system external inspection device, and FIG. FIG. 15 is a side view of the inspection device, FIG. 15 is a flow chart showing an operation example of the magnetic calculation device, FIG. 16 is a flow diagram showing an operation example of the deterioration calculation device, and FIG. 17 is measurement data used for judgment of damage. Fig. 18 is a relational diagram of measurement data used for judging deterioration,
FIG. 19 is a plan view showing an example of a display device, FIGS.
Fig. 22, Fig. 23, Fig. 23, Fig. 24, and Fig. 25 are characteristic diagrams showing changes in magnetic properties due to plastic strain of duplex stainless steel, Fig. 26, Fig. 27, Fig. 28, Fig. Figure 29, Figure 30, Figure 31
Figures 32 and 33 are characteristic diagrams showing changes in mechanical properties and magnetic properties related to strain aging of duplex stainless steels, respectively, 34, 35, 36, 37 and 37. 38 and 39 are characteristic diagrams showing changes in mechanical properties and magnetic properties with respect to strain aging of low alloy steels, and FIGS. 40, 41 and 42 explain strain characteristic estimation methods, respectively. It is a characteristic view with respect to aging time. 1 …… Measurement object such as equipment or piping used in nuclear power plants, 21 …… Excitation coil, 22 …… Excitation controller, 31 …… Magnetic sensor, 32 …… Magnetic sensor controller, 41 …… Driving device, 42… ... Drive controller, 51
...... Magnetic computing unit, 52 …… Magnetic property database, 61…
... Deterioration calculation device, 62 ... Database showing relationship between magnetism of measurement object 1 and deterioration degree, 71 ... Display device, 72 ... Mouse,
210 …… Excitation coil, 211 …… Coaxial structure core, 212 ……
Horseshoe-shaped core, 213, 214 ... Exciting coils whose magnetic measuring directions are orthogonal to each other, 215 ... Dummy exciting coil, 310 ... Magnetic sensors such as Hall elements and detection coils, 313, 314 ... Magnetic sensors whose magnetic measuring directions are orthogonal to each other, 330 …… SQUID
Sensor, 331 ... Pickup coil, 332 ... Refrigerant such as liquid helium, 333 ... Cryostat capable of measuring external magnetic field, 334 ... Magnetic shield, 511 ... Input memory, 51
2 ... Magnetic data display device, 513 ... Magnetic field analysis calculation device,
514 ... magnetic field analysis code, 516 ... depth data processing, 517 ... anisotropic data processing, 561 ... anisotropic data memory, 562 ... depth data memory, 563 ... magnetism Anisotropy data preprocessing, 564 ... Magnetic depth data preprocessing, 5
65 ... Deterioration judgment calculation procedure, 610 ... Reactor pressure vessel, 611
...... Control rod, 612 ...... Control rod guide tube, 613 ...... Upper grid, 614 …… Reactor core support, 615 …… Reactor water, 617 …… Crane, 618 …… Monitor, 620 …… Rail, 630 …… Piping , 810 ...... fixable ring that can be split into two, 810 ... fixed ring that can be split into two, 811 ... rotating ring, 820 ... drive motor, 821 ... gear box, 823 ... rotating motor with position detection function, 824 ... Roller, 825 ... Pulley, 826
...... Encoder, 827 ...... Position detection encoder, 850 ...
… Head part, 891 …… Frame with four columns, 892…
… Sucker, 893 …… Vacuum pump, 894 …… Drive shaft, 89
5 …… X-axis motor, 896 …… Gear box, 897 …… Y-axis motor, 898 …… Drive shaft, 899 …… Air cylinder equipped with gear box, 900 …… Cable, 910 …… Stepping motor, etc.922… … Timing belt, 923 …… Shaft, 924 …… Pulley, 925 …… Stepping motor, etc., 926 …… Timing belt, 928 …… Pulley, 931
……Air cylinder.

Front page continuation (72) Yuichi Ishikawa Yuichi Ishikawa 502 Jintamachi, Tsuchiura-shi, Ibaraki Machinery Research Laboratory, Hiritsu Manufacturing Co., Ltd. (72) Inventor Kunio Enomoto 502 Jinritsu-machi, Institute of Mechanical Research, Tsuchiura-shi, Ibaraki Prefecture, Hiritsu Seisakusho Co., Ltd. Documents JP 61-277051 (JP, A) JP 55-46143 (JP, A) JP 60-243526 (JP, A) JP 58-60248 (JP, A) JP 61- 172059 (JP, A) JP 59-178356 (JP, A) JP 60-147646 (JP, A) Actually opened 61-161659 (JP, U)

Claims (5)

[Claims] 1. An inspection apparatus for a metal material, wherein a magnetic field is applied to a measuring body by an exciting coil or the like, and deterioration or damage is detected from a change in magnetism generated in the measuring body thereby, saturation magnetism of the measuring body, residual Magnetic, coercive force, equipped with a magnetic measuring device that detects magnetic properties such as Barkhausen noise, and an arithmetic device that determines the state of the magnetic field in the measurement region by a numerical analysis method. It is equipped with an arithmetic unit for determining the degree of strain damage and deterioration of materials from a database of the relationship between changes in magnetic properties such as Barkhausen noise and damage and deterioration of metal materials, and a display device for outputting, and an exciting coil and a magnetic field. An array type sensor is used, and a dummy excitation coil is provided at the outermost peripheral part to ensure the uniformity of the magnetic field at the outermost peripheral part. . 2. The deterioration detecting device for a metal material according to claim 1, wherein the directivity of the exciting coil and the directivity of the magnetic sensor are alternately arranged in an orthogonal direction. 3. A metal according to claim 1, wherein a superconducting quantum interference device (SQUID) sensor is used as the magnetic sensor to provide a pickup coil structure of the SQUID sensor capable of detecting magnetic anisotropy. Material deterioration and damage detection device. 4. A method of determining strain damage or deterioration from magnetic characteristics, assuming a certain strain amount for the measured BH characteristic, and measuring the BH measured from a database of aging at that strain amount. The B-H characteristic closest to the characteristic is selected, the aging time is determined, and then the B-H characteristic closest to the B-H characteristic measured from the strain amount database at this aging time is determined based on this aging time. Selected,
Newly determine the amount of strain, based on the amount of strain, similarly repeat the above method, the finally converged amount of strain and aging time to determine the strain damage and deterioration of the measured metal A method for detecting material deterioration and damage. 5. A Barkhausen noise measured from a database of aging at a certain strain amount assuming a certain strain amount with respect to the measured Barkhausen noise spectrum, as a method for determining strain damage or deterioration from magnetic properties. Select the Barkhausen noise spectrum closest to the spectrum, determine the aging time, and then, based on this aging time, the Barkhausen noise closest to the Barkhausen noise spectrum measured from the strain amount database at this aging time. Select a spectrum, re-determine the strain amount, repeat the above method based on the strain amount, and determine the strain damage or deterioration of the measured object from the finally converged strain amount and aging time. A method for detecting deterioration and damage of a metal material, characterized by: