KR102039927B1 - Probe and fault edtection apparatus including the same - Google Patents

Abstract

Embodiments of the present invention provide a first pancake coil that applies a first eddy current signal to a reference cut coupon of the same material as the test specimen and detects a reference signal in response to the applied first eddy current signal from the reference cut specimen. ; And a second pancake coil configured to apply a second eddy current symbol to the test body to detect a detection signal in response to the second eddy current signal.
Thus, embodiments of the present invention can remove the noise due to the impurity effect on the surface of the test body through the first pancake coil and the second pancake coil, it is possible to more accurately detect the defect.

Description

PROBE AND FAULT EDTECTION APPARATUS INCLUDING THE SAME}

Various embodiments of the present invention relate to a probe and a defect detection apparatus including the same, and more particularly, to a probe and a defect detection apparatus including the same for detecting a test specimen defect by obtaining a more accurate detection signal.

In general, non-destructive inspection refers to a method of externally inspecting a defect such as internal pores or cracks in a specimen (inspection), an internal defect in a welded portion, etc. without destroying the specimen.

Such non-destructive examinations include radiographic examination, ultrasonic examination, laser beam examination and eddy current.

Among these, the eddy current inspection method is a method of detecting an external defect of a test specimen by applying a current to a general eddy current inspection coil, and detecting (detecting) a surface defect of the test specimen by analyzing a transient signal formed by an instantaneous current.

Unlike the ultrasonic test method, which requires a contact medium, the eddy current test method is a non-contact method, so it can be measured without the contact medium between the test specimen and the probe.However, the impurities in the eddy current signal are increased due to surface impurities such as scale and corrosion. It is difficult, and there is a problem in that the test object is partially magnetized and misdetects defects caused by the presence of a residual magnetic field.

Korean Patent No. 10-1339117, Name of the invention: Apparatus and method for detecting a back defect using pulse and current.

In order to solve the above problems, embodiments of the present invention has an object to provide a probe capable of detecting a specimen defect through the eddy current test method and a defect detection apparatus including the same.

In addition, embodiments of the present invention has a further object to provide a probe and a defect detection device comprising the same for minimizing the noise caused by the impact of impurities on the surface of the test object.

In addition, embodiments of the present invention is another object to provide a probe and a defect detection device comprising the same for detecting the internal defect of the test object more accurately by self-saturating the test object.

According to an embodiment of the present invention, the first eddy current signal is applied to a reference cutting specimen (coupon) of the same material as the test body, and the first signal for detecting the reference signal in response to the applied first eddy current signal from the reference cutting specimen 1 pancake coil; And a second pancake coil configured to apply a second eddy current symbol to the test body to detect a detection signal in response to the second eddy current signal.

Here, the transducer is a sensor housing; A sensor jig rod disposed inside the sensor housing and configured to mount the first pancake coil and the second pancake coil; And a push part disposed above the sensor jig rod and the sensor housing.

In addition, the probe may further include an electromagnet disposed around the sensor housing to apply a magnetic field generated by a magnetic force generated by a current to the test specimen to make the magnetic saturation state.

In addition, the probe may further include an outer housing having a plurality of wheels and holes and for mounting the electromagnet and the sensor mounting part.

The probe may further include a ferrite core disposed between the first pancake coil and the second pancake coil to agglomerate the magnetic force.

In this case, the second pancake coil may receive a detection signal generated from a predetermined depth inside the self-saturated test body when the test body is magnetically saturated by the magnetic field.

According to another embodiment of the present invention, a transducer for selectively describing the above-described features; And a control device for detecting noise by analyzing the reference signal and the detection signal generated by the probe.

Here, the control device may detect a defect generated in the test body through the detection signal from which the detected noise is removed.

In this case, the first pancake coil may generate the first eddy current signal according to a current, and apply the generated first eddy current signal to the reference cutout coupon, wherein the second pancake coil is according to a current. The second eddy current signal may be generated and the generated second eddy current signal may be applied to the test body.

The defect detecting apparatus may further include a saturation detecting apparatus that detects a magnetic saturation state and permeability from the test body when the test body is self saturated.

In addition, the test body may be a magnetic material or a nonmagnetic material, and the magnetic material or the nonmagnetic material may include a component of a heat exchanger.

According to another embodiment of the present invention, in the defect detection method by the control device of the defect detection device, the first reference signal in response to the first eddy current signal applied to the reference cutting specimen (coupon) of the same material as the test object Receiving from a pancake coil; Receiving a detection signal from a second pancake coil in response to a second eddy current signal applied into the test body; Analyzing the received reference signal and the detection signal to remove noise included in the detection signal; And analyzing the detection signal from which the noise has been removed to detect an internal defect of the test object.

In this case, the receiving from the second pancake coil may receive a detection signal from the inside of the magnetically saturated test body when the test body is magnetically saturated by the magnetic field of the magnetic force applied from the electromagnet.

According to embodiments of the present invention, by removing the noise caused by the influence of impurities on the surface of the test body through the first pancake coil and the second pancake coil, there is an effect that more accurate defect detection is made.

In addition, embodiments of the present invention has the effect of increasing the detection sensitivity, the more accurate defects can be detected by removing noise from the defect detection occurring inside the test body.

In addition, the embodiments of the present invention can accurately detect defects directly under the surface of the test body by penetrating the second eddy current signal to the depth deep inside the test body while the test body is self-saturated and the magnetic permeability is low through the electromagnet. By making it constant, there is an effect of removing the noise caused by the residual magnetic field and / or the influence of impurities.

Not limited to the above-mentioned effects, other effects that are not mentioned can be clearly understood by those skilled in the art from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are provided to assist in understanding the present invention, and provide embodiments with a detailed description. However, the technical features of the present invention are not limited to the specific drawings, and the features disclosed in the drawings may be combined with each other to constitute new embodiments.
1 is a view showing the configuration of a probe for detecting a specimen defect according to an embodiment of the present invention.
2 (a) and 2 (b) are views showing the structure of the sensor mounting portion according to the embodiment of the present invention and the transducer structure showing the relationship between the sensor mounting portion and the electromagnet.
Figure 2 (c) is a view showing a further configuration of the transducer according to an embodiment of the present invention.
3 is a schematic diagram showing a defect detection apparatus according to an embodiment of the present invention.
4 is a graph showing the magnetic saturation state and the magnetic permeability (magnetic transmittance) state of the test specimen according to the embodiment of the present invention.
5 is a flowchart illustrating a defect detection method according to an embodiment of the present invention.
6 is a graph showing the detection sensitivity of a detection signal for a normal specimen (test specimen) between a conventional single ECT sensor and the self-saturated ECT sensor of the present embodiments.
7 is a graph showing the detection sensitivity of the detection signal for the defective corrosion test piece (test specimen) between the existing single ECT sensor and the self-saturated ECT sensor of the present embodiments.

The terms disclosed in the following examples and claims are only used to describe specific examples, but are not limited thereto.

For example, the terms 'comprise' or 'comprise' disclosed in the following embodiments and claims are intended to mean that a corresponding component may be included unless specifically stated otherwise. It is to be understood that the present invention does not exclude other components, but includes other components.

In addition, the "suffix" as a suffix for the components disclosed in the following description and claims are given or used in consideration of ease of specification, and do not have meanings or roles distinguished from each other.

In addition, the test specimen (test specimen) disclosed in the following description and claims may be a magnetic material or a non-magnetic material as a test stand, and the magnetic or non-magnetic material may include a component (tuning) of a heat exchanger. However, the magnetic or nonmagnetic material is not limited to the parts of the heat exchanger, and all subjects requiring nondestructive testing can be included in this category.

In addition, it is to be understood that the transducer and the defect detection apparatus disclosed in the following description and the claims correspond to the configurations for applying the eddy current inspection method.

Hereinafter, with reference to the accompanying drawings in terms of hardware configuration and method of various aspects will be described in more detail.

1 is a view showing the configuration of a probe for detecting a specimen defect according to an embodiment of the present invention.

Referring to FIG. 1, the transducer 100 according to an embodiment of the present invention includes a first pancake coil 110 and a second pancake coil 120, and further includes an electromagnet 130 and a ferrite core 140. can do.

The first pancake coil 110 receives a current from the outside, and generates a first eddy current signal based on the current, and the generated first eddy current signal is applied to the reference cut specimen 101 (coupon) having the same material as that of the test body 10. Can be authorized.

Alternatively, the first pancake coil 110 may apply the generated first eddy current signal to the air.

In this case, the first pancake coil 110 generates a reference signal from the reference cutting specimen 101 by this reaction when the first eddy current signal responds to the reference cutting specimen 101 of the same material as the test body 10. The reference signal may be received (detected) in response to the reference cut specimen 101, or may receive a reference signal in response to the first eddy current signal in the air.

The second pancake coil 120 may be spaced apart from the first pancake coil 110 by a predetermined interval and disposed below. The second pancake coil 120 may receive a current from the outside and generate a second eddy current signal based on the current to be applied to the test body 10.

In one embodiment, the electromagnet 130 is spaced apart from the first pancake coil 110 and the second pancake coil 120, and receives a current from the outside, it can generate a magnetic field by the magnetic force according to the current The applied magnetic field may be applied to the test body 10 to saturate the inside of the test body 10.

In this case, the degree of magnetic saturation may vary according to the strength of the magnetic field applied to the electromagnet 130, and the magnetic field due to the magnetic force generated by the electromagnet 130 may vary depending on the strength of the current.

The ferrite core 140 may be disposed around the center between the first pancake coil 110 and the second pancake coil 120 to increase the magnetic field strength due to the magnetic force of the electromagnet 130.

When the ferrite core 140 is provided between the first pancake coil 110 and the second pancake coil 120, the magnetic force generated in the electromagnet 130 may be aggregated to increase the magnetic field strength (strength) due to the magnetic force. This high intensity magnetic field can be applied to the test body 10.

Accordingly, the test body 10 may be magnetically saturated by a high-intensity magnetic field applied from the electromagnet 130, and when the magnetic body is saturated, the permeability of the test body 10 may naturally be lowered.

In this case, the second pancake coil 120 described above may penetrate the magnetic field due to the magnetic force to a predetermined depth ρ of the magnetically saturated test body 10 when the test body 10 is magnetically saturated and the magnetic permeability is low. In response to the magnetic field, a detection signal generated at a predetermined depth p can be received.

In this case, the predetermined depth ρ that may be inspected may vary depending on the material of the test body 10, and may be more than twice as large as that of the existing eddy current sensor even if it depends on the material of the test body 10. For example, if the eddy current of an existing eddy current sensor penetrates to a depth of 30 mm, the magnetic field can reach a penetration depth of 60 mm or more, which is approximately twice as large as this penetration depth.

Accordingly, when the test body 10 is magnetically saturated by the magnetic field, the second pancake coil 120 may receive a detection signal generated up to a predetermined depth ρ inside the self-saturated test body 10. will be.

As described above, in the present embodiment, the first pancake coil 110 and the second pancake coil 120 may analyze the difference between the detected detection signal and the reference signal to remove noise included in the detection signal. The noise ratio (S / N) can be improved.

On the other hand, the second pancake coil 110, 120 and the test body 10 described above to have a constant lift-off, it can be mounted to the sensor mounting portion to reduce the impact from the attraction of the electromagnet 130, The first pancake coil 110 and the ferrite coil 140 may also be mounted to the sensor mounting portion, and the above-described electromagnet 130 may be mounted to the outside of the sensor mounting portion of the probe.

Here, the structure of the sensor mounting portion mentioned is as follows.

2 (a) and 2 (b) is a view showing the structure of the sensor mounting portion according to an embodiment of the present invention and the transducer structure showing the relationship between the sensor mounting portion and the electromagnet.

As shown, the sensor mounting portion (100a) of the transducer 100 according to the present embodiment is disposed in the sensor housing 150, the sensor housing 150, the first pancake coil 110 and the second pancake The sensor jig rod 160 for inserting and mounting the coil 120 and the sensor jig rod 160 and the sensor housing 150 are disposed on the sensor jig rod 160 and the sensor housing 150 of the sensor housing 150. It may include a push unit 170 to be fixed therein.

In this case, the electromagnet 130 described with reference to FIG. 1 may be arranged to insert the sensor housing 150 to surround it. Therefore, the second pancake coil 120 disposed inside the electromagnet 130 and the sensor housing 150 may have a constant lift-off.

Figure 2 (c) is a view showing a further configuration of the transducer according to an embodiment of the present invention.

Referring to Figure 2 (c), the transducer 100 according to an embodiment of the present invention is an outer housing 180 for mounting the sensor mounting portion (100a) and the electromagnet 130, etc. described in Figures 1 to 2 (b) ) May be further included.

The outer housing 180 has the same shape and forms a quadrangle by combining the first housing 181 and the second housing 182 facing each other, and when the first housing 181 and the second housing 182 are coupled to each other. The cover 183 may be coupled to the upper portion. As such, the sensor mounting unit 100a and the electromagnet 130 described in FIGS. 1 to 2 (b) are mounted inside the first housing 181, the second housing 182, and the cover 183, which are integrally coupled to each other. Can be.

The first housing 181 and / or the second housing 182 may be provided with a plurality of wheels 184 and holes 185. In this case, the reason why the plurality of wheels 184 are provided is, for example, to maintain a predetermined interval in inspecting the test body 10 when the test object 10 is a flat surface or a circular pipe. However, the present invention is not limited thereto, and the transducer 100 may not be fixed, and a plurality of wheels 184 may be provided to ensure mobility.

3 is a schematic diagram showing a defect detection apparatus according to an embodiment of the present invention.

Referring to FIG. 3, a defect detection apparatus according to an embodiment of the present invention may include a probe 100 and a control device 300, and may further include a current supply device 200 and a saturation detection device 400. have. Since the transducer 100 has been sufficiently described above with reference to FIGS. 1 and 2 (c), the description thereof is omitted, but it is of course applied to the present embodiment.

In an embodiment, the current supply device 200 may generate a current to supply current to the first pancake coil 110, the second pancake coil 120, and the electromagnet 130 described above, and the control device described below ( The current (voltage) can also be further supplied to the 300 and the saturation detection device 400.

In this case, the first pancake coil 110 generates a first eddy current signal according to the current supplied from the current supply device 200 and applies it to the reference cut specimen 101 (coupon) of the same material 101 as the test body 10. The second pancake coil 120 may generate a second eddy current signal according to the current supplied from the current supply device 200 and apply it to the test body 10 disposed below.

The control device 300 compares and analyzes the reference signal and the detection signal generated by the transducer 100 to detect and remove noise caused by the influence of impurities on the surface of the test object, thereby detecting the test object 10 through the detection signal from which the detected noise is removed. It will be possible to accurately detect the defects generated inside.

In one embodiment, the saturation detection apparatus 400 may detect the magnetic saturation state and permeability (magnetic transmittance) generated from the test body 101 when the test body 101 is self saturated.

In this case, the mentioned magnetic saturation state and permeability (magnetic transmittance) may be represented as shown in FIG. 4, for example, in the case of ordinary steel. On the graph of the abscissa magnetic field strength (H) and the ordinate electric flux density (B) shown in FIG. 4, the permeability increases until the magnetic field strength is approximately 2500, the flux density B is approximately 1.5, and then gradually decreases. The magnetic saturation may gradually increase and then decrease from the inflection point where it meets the permeability.

Accordingly, in the case of general steel, the second pancake coil 120 has a magnetic saturation state after an inflection point formed at an electric flux density B of approximately 1.5 and a magnetic field strength H of 5000 as shown in FIG. 4. When the permeability is formed, it may be desirable to apply a magnetic field due to the magnetic force to the magnetically saturated test specimen 101 according to the permeability.

More preferably, in the case of ordinary steel, the second pancake coil 120 has a magnetic saturation and magnetic permeability at an electric flux density (B) in the range of about 0.1 to 0.6 and a magnetic field strength (H) of 9000 to 12000. In this case, the magnetic field due to the magnetic force may be penetrated to a predetermined depth of the magnetically saturated test specimen 101 according to the permeability.

As described above, in the present embodiment, even when the test body 101 is magnetically saturated and the magnetic permeability is low, the magnetic field caused by the magnetic force penetrates to the depth ρ deep inside the test body 101, so that even a defect directly under the surface of the test body 101 can be easily obtained. It can be detected and the magnetic field in the test object can be made constant to remove the noise caused by the residual magnetic field and the influence of impurities.

5 is a flowchart illustrating a defect detection method according to an embodiment of the present invention.

Referring to FIG. 5, a defect detection method according to an embodiment of the present invention may include steps 510 to 540 performed by the control device 300 of the defect detection apparatus.

First, in step 510, the control device 300 of the defect detection apparatus when the first pancake coil 110 applies the first eddy current signal to the reference cut specimen (101, coupon) of the same material as the test body 10, In the reference cut specimen 101, a reference signal in response to the first eddy current signal may be received from the first pancake coil 110.

In operation 520, when the second pencake coil 120 applies a magnetic field caused by a magnetic force to the inside of the test body 101, the control device 300 of the defect detection apparatus may output a detection signal in response to the magnetic field to the second pancake coil. Can be received from inside of 120.

In addition, in step 520, the control device 300 of the defect detection apparatus may determine a predetermined depth ρ of the self-saturated test body 101 when the test body 10 is magnetically saturated by a magnetic field applied from the electromagnet 130. ) May be detected from the second pancake coil 120.

In this case, the predetermined depth ρ that may be inspected may vary depending on the material of the test body 10, and may be more than twice as large as that of the existing eddy current sensor even if it depends on the material of the test body 10. For example, if the eddy current of an existing eddy current sensor penetrates to a depth of 30 mm, the magnetic field can reach a penetration depth of 60 mm or more, which is approximately twice as large as this penetration depth.

Accordingly, the control device 300 of the defect detection apparatus may receive, for example, a detection signal generated at an internal depth ρ of 1 to 60 mm of the test body 10 from the second pancake coil 120.

In operation 530, the control device 300 of the defect detection apparatus analyzes the reference signal received by operation 510 described above and the detection signal received by operation 520 described above, and relates to the influence of impurities on the surface of the test object included in the detection signal. By removing the noise, the signal-to-noise ratio (S / N) can be improved.

Finally, in step 540, the control device 300 of the defect detection apparatus may analyze the detection signal from which the noise is removed to accurately detect a defect at, for example, an internal depth ρ of 1 to 60 mm of the test object 101. There will be.

For example, the control device 300 of the defect detection apparatus has following formula (1) and electric flux density (B) for obtaining the penetration depth δ at which the second eddy current signal of the second pencake coil 120 has reached. The internal defect of the test body 101 can be easily detected from the detection signal from which the noise is removed based on Equation (2) below.

.... 식 (1)

.... Equation (1)

In the formula (1), ρ is the resistivity, ω is the angular frequency, μ is the magnetic permeability (magnetic permeability) μ r μ 0, μ r is the relative permeability, μ 0 is the vacuum permeability (permeability of free space), and ε indicates permittivity.

Ｂ = μH = μrμ0 .... Equation (2)

In Equation (2), H may indicate magnetic field strength.

As described above, in the present exemplary embodiment, more accurate defect detection may be achieved by removing noise due to the impurity effect on the surface of the test body through the first pancake coil and the second pancake coil.

Comparative Example

6 is a graph showing the detection sensitivity of the detection signal for a normal test piece (test specimen) between a conventional single ECT sensor (Electronic Control Transmission sensor) and the self-saturated ECT sensor of the present embodiments, Figure 7 is a conventional single ECT sensor It is a graph which shows the detection sensitivity of the detection signal with respect to the corrosion test piece (test body) between the magnetic saturation ECT sensors of these Examples.

6 and 7, the magnetic saturation ECT sensor of the present embodiment may operate as the first pancake coil 110 as a reference sensor (eddy current sensor) and the second pancake coil 120 as a sensing sensor (eddy current sensor). When referring to the transducer 100 including these and the electromagnet 130, the existing single ECT sensor refers to the transducer including a permanent magnet and an eddy current sensor.

Here, the conventional single ECT sensor shown in FIG. 6 and the magnetic saturation ECT sensor according to this embodiment are obtained by the magnetic saturation ECT sensor of the present embodiments when the detection signals are respectively obtained from a normal specimen (test specimen) without defects. The detection signal has a higher phase angle (Phase Angle) compared to the detection signal acquired from the conventional single ECT sensor, indicating a high detection sensitivity.

On the other hand, the conventional single ECT sensor shown in FIG. 7 and the magnetic saturation ECT sensor according to the present embodiment acquire the detection signals from corrosion specimens (test specimens) having defects therein. The detection signal obtained at is much larger than the detection signal obtained from the conventional single ECT sensor, and thus the sensitivity is very high due to the much larger phase angle.

Although the present invention has been described as described above, it will be appreciated by those skilled in the art that the present invention may be implemented in other forms while maintaining the technical spirit and essential features of the present invention. .

Therefore, the above-described embodiments are merely exemplary and are not intended to limit the scope of the present invention only to the above embodiments. In addition, the flowcharts shown in the drawings are merely exemplary in order to obtain the most desirable results in practicing the present invention, and other steps may be added or some steps may be deleted.

The scope of the present invention will be defined by the claims, but all modifications or variations derived from a configuration equivalent to that derived directly from the claims description are also included within the scope of the present invention. Should be interpreted as

10: test body
100: probe
100a: sensor mounting
101: reference cut specimen
110: first pancake coil
120: second pancake coil
130: electromagnet
140: ferrite core
150: sensor housing
160: sensor jig rod
170: push part
180: outer housing
181: first housing
182: second housing
183: cover
184: Wheels of Revenge
185: Multiple Halls
200: voltage supply
300: control unit
400: Saturation Detection Device

Claims (15)

A first pancake coil configured to apply a first eddy current signal to a reference cutting specimen made of the same material as the test body, and detect a reference signal in response to the applied first eddy current signal from the reference cutting specimen; And a second pancake coil configured to apply a second eddy current signal to the test body and detect a detection signal in response to the second eddy current signal.
A control device for detecting noise by analyzing a reference signal and a detection signal generated by the transducer; And
And a saturation detection device that detects a magnetic saturation state and permeability from the test body when the test body is self saturated.
Here, the transducer,
And a sensor mounting unit configured to mount the first pancake coil and the second pancake coil.
The sensor mounting unit may include: a sensor housing; and a sensor jig rod disposed inside the sensor housing to insert and mount the first pancake coil and the second pancake coil; And a push part disposed above the sensor jig rod and the sensor housing.
An electromagnet wrapped around the sensor housing and configured to apply a magnetic field generated by a magnetic force generated by a current to the test body to form a magnetic saturation state; An outer housing;
Wherein the plurality of wheels maintains a predetermined distance between the test body and the probe and allows the probe to move along the test body. delete delete delete The method of claim 1,
A ferrite core disposed between the first pancake coil and the second pancake coil to agglomerate the magnetic force;
Defect detection device further comprising. The method of claim 1,
The second pancake coil,
And a detection signal generated from a predetermined depth inside the magnetically saturated specimen when the specimen is magnetically saturated by the magnetic field. delete The method of claim 1,
The control device,
And detecting a defect generated in the test object through a detection signal from which the detected noise is removed. The method of claim 1,
The first pancake coil,
And generating the first eddy current signal according to a current, and applying the generated first eddy current signal to the reference cutout coupon. The method of claim 1,
The second pancake coil,
And generating the second eddy current signal in accordance with the current, and applying the generated second eddy current signal to the test body. delete The method of claim 1,
The test object is a defect detection device, characterized in that the magnetic material or non-magnetic material. The method of claim 12,
The magnetic or nonmagnetic material comprises a component of a heat exchanger. delete delete

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