Ultrasonic testing device with variable frequency

Abstract

The present invention relates to an ultrasonic testing device having a variable frequency capable of automatically changing a frequency according to a thickness and thereby detecting an internal defect in an object having various thicknesses. The ultrasonic testing device can include a nozzle that sprays a medium toward an object to form a medium column, and a plurality of probes arranged in the nozzle to generate ultrasonic waves.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an ultrasonic testing apparatus with variable frequency capable of detecting internal defects in an object having various thicknesses by automatically changing a frequency according to the thickness. BACKGROUND

[0002] For example, in a heavy plate production line of a steel mill, ultrasonic testing has been performed in a calibration line before shipment to secure the quality of the product that has been manufactured. The ultrasonic testing diagnoses whether a defect such as a crack, an inclusion, and segregation exists in the product by transmitting an ultrasonic wave to the product and receiving and analyzing the ultrasonic wave reflected from the product.

[0003] In the ultrasonic testing process, a gap between the product surface and the probe is filled with water, and then an ultrasonic wave is transmitted. A contact medium is required to transfer the ultrasonic wave energy oscillated from the probe to the product. In the contact medium, water is a representative medium having excellent ultrasonic wave transmission efficiency.

[0004] Meanwhile, in a heavy plate manufacturing site of a steel mill, heavy plates having various thicknesses are being manufactured as products. Ultrasonic waves are scattered or absorbed when they propagate inside a metal, and thus their energy is reduced. The degree of energy reduction varies depending on the frequency of the ultrasonic wave and the type and grain structure of the metal.

[0005] In consideration of such ultrasonic wave attenuation, standards for ultrasonic testing are established. For example, for a product having a thickness of 80 mm or less, an ultrasonic wave having a frequency of about 5 MHz is applied, and for a product having a thickness greater than 80 mm, an ultrasonic wave having a frequency of about 2 MHz is applied.

[0006] Therefore, there is a problem in that a 5 MHz ultrasonic tester and a 2 MHz ultrasonic tester are separately provided to test all products having various thicknesses, and need to be selectively used according to the thickness. Generally, since an ultrasonic tester for testing a full width of a product is very expensive because it includes several hundreds of ultrasonic sensors, a signal processing array, and defect determination software, installation of two testers requires a large amount of capital and manpower, and the maintenance cost increases as the number of equipment increases.

[0007] As related art, there is an invention disclosed in Japanese Unexamined Utility Model Publication No. 63-200161 U. SUMMARY

[0008] TECHNICAL PROBLEM

[0009] An aspect of the present disclosure is to provide an ultrasonic testing device with variable frequency capable of detecting internal defects in objects having various thicknesses by automatically changing frequency according to thickness.

[0010] Technical Solution

[0011] According to an aspect of the present disclosure, an ultrasonic testing device includes a nozzle that sprays a medium toward an object to form a medium column, and a plurality of probes arranged on the nozzle to oscillate ultrasonic waves.

[0012] The ultrasonic testing device can further include an ultrasonic reflector rotatably installed in the nozzle so that ultrasonic waves of a probe selected from among the plurality of probes are transmitted to the object.

[0013] The ultrasonic testing device can further include a plurality of inlet waveguides branched from an outlet waveguide, and the plurality of inlet waveguides have a plurality of probes assigned to each of the plurality of inlet waveguides, wherein the nozzle is formed of one outlet waveguide.

[0014] Advantageous Effects

[0015] As set forth above, according to exemplary embodiments in the present disclosure, one ultrasonic testing device can detect internal defects in all products having various thicknesses, and thus can greatly save installation and operation costs of the ultrasonic testing device and manpower.

[0016] In addition, according to exemplary embodiments in the present disclosure, one ultrasonic testing device can test all products, and thus can more effectively integrate and manage internal defects in products compared to a case where a plurality of ultrasonic testing devices are operated, thereby improving quality and productivity of products. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is a diagram schematically showing an ultrasonic testing device according to a first exemplary embodiment in the present disclosure.

[0018] Figure 2 FIG. 2 is a perspective view showing main parts of the ultrasonic testing device according to the first exemplary embodiment in the present disclosure.

[0019] Figure 3 FIG. 3 is a diagram for describing a control procedure of the ultrasonic testing device according to the first exemplary embodiment in the present disclosure.

[0020] Figure 4 FIG. 4 is a sectional view showing main parts of an ultrasonic testing device according to a second exemplary embodiment in the present disclosure.

[0021] Figure 5is a diagram for describing a control procedure of an ultrasonic testing device according to a second exemplary embodiment in the present disclosure. DETAILED DESCRIPTION

[0022] Hereinafter, the present disclosure will be described in detail with reference to exemplary drawings. It is noted that, when components of the drawings are given reference numerals, the same components will be indicated by the same reference numerals even if they are shown in different drawings. Also, in describing the exemplary embodiments in the present disclosure, well-known functions or constructions will not be described in detail since they can unnecessarily obscure the understanding of the present disclosure.

[0023] Figure 1 is a diagram schematically showing an ultrasonic testing device according to a first exemplary embodiment in the present disclosure, Figure 2 is a perspective view showing main parts of the ultrasonic testing device according to the first exemplary embodiment in the present disclosure, and Figure 3 is a diagram for describing a control procedure of the ultrasonic testing device according to the first exemplary embodiment in the present disclosure.

[0024] As shown in these drawings, the ultrasonic testing device according to the first exemplary embodiment in the present disclosure can include a nozzle 10 and a plurality of probes 20, 21, and 22.

[0025] The nozzle 10 can be installed at the lower side of an object 1 such as a thick steel plate conveyed by a conveying device (for example, a guide roller 3), and sprays a medium 2 (for example, water) toward the object to form a medium column 4 (for example, a water column).

[0026] Such a nozzle 10 should be able to form a stable medium column 4 in close contact with the lower surface of the object 1. To this end, the inner diameter of the nozzle is limited.

[0027] When the inner diameter of the nozzle 10 is increased, the volume and mass of the medium column 4 are increased, and thus the height of the medium column is abruptly decreased. Also, since pulsation is formed inside the medium column, it becomes difficult to stably transmit ultrasonic waves.

[0028] On the other hand, when the inner diameter of the nozzle 10 is too small, as the test area becomes small and the flow rate increases, the flow of the medium 2 becomes unstable, and thus it is not possible to stably transmit ultrasonic waves.

[0029] Therefore, the relationship between the inner diameter d of the nozzle 10 and the width w or diameter of the probe surface needs to satisfy the following [Equation 1]. In this case, the most stable ultrasonic testing is possible. Here, the probe surface refers to a surface on which ultrasonic waves are basically oscillated by the probe 20.

[0030] [Equation 1]

[0031] d / 2 < w < d

[0032] In the ultrasonic testing apparatus according to the first exemplary embodiment of the present disclosure, frequency switching can be performed using one nozzle 10 having an inner diameter d having a correlation with a width w or diameter with respect to a surface of a probe as in Equation 1 above.

[0033] The medium column 4 can be formed to have a height of several tens of millimeters (mm) from the outlet of the nozzle 10, and can transmit and receive ultrasonic waves through such a medium column. Since water is used as a medium having excellent ultrasonic wave transmission efficiency, the medium column can be formed of a water column.

[0034] The ultrasonic testing apparatus according to the first exemplary embodiment of the present disclosure can further include a medium circulation unit 30 that forms the medium column 4 by spraying the medium 2 from the nozzle 10, recovers the medium falling from the medium column, and circulates the medium back to the nozzle.

[0035] The medium circulation unit 30 can include a medium receiver 31, a recovery pipe 32, and a supply pipe 33.

[0036] The medium receiver 31 can be installed outside the nozzle 10 and can be configured to receive the medium 2 falling from the medium column 4. The medium receiver can be formed in a cylindrical or box shape around the nozzle.

[0037] The recovery pipe 32 can be connected to the medium receiver 31 and can be configured to recover the medium 2 in the medium receiver. The medium falling from the medium column 4 and collected in the medium receiver can be supplied to the recovery pipe.

[0038] A filter 34 for filtering the medium 2 discharged from the medium receiver 31 can be installed in the recovery pipe 32, so that the medium from which impurities are removed can be resupplied to the nozzle 10.

[0039] The supply pipe 33 serves to supply the medium 2 of the recovery pipe 32 to the nozzle 10, and can be in communication with the nozzle 10 and the recovery pipe 32, respectively.

[0040] A circulation pump 35 that provides a spraying pressure to the nozzle 10 can be installed between the recovery pipe 32 and the supply pipe 33. The medium column 4 can be formed by enabling the nozzle to spray the medium 2 at a constant pressure according to the pressure provided by the circulation pump. By controlling the circulation pump, the spraying pressure of the nozzle can be controlled.

[0041] A plurality of probes 20 can be arranged on the nozzle 10 to oscillate ultrasonic waves.

[0042] In particular, each of the plurality of probes 20 can be fixedly installed on the side wall of the nozzle 10 at intervals from each other, and can transmit and receive ultrasonic waves for detecting internal defects in the object 1 through the medium column 4.Figures 1 to 3 An example is shown in which two probes 21 and 22 are symmetrically installed with respect to the nozzle.

[0043] The plurality of probes 20 can oscillate ultrasonic waves having different frequencies. For example, one probe 21 can oscillate ultrasonic waves having a frequency of about 5 MHz, and another probe 22 can oscillate ultrasonic waves having a frequency of about 2 MHz.

[0044] Each of the probes 20 can be connected to a defect detection unit (not shown) through wired and wireless communication, which processes and calculates the ultrasonic wave signals received from the object 1 to analyze whether there is an internal defect in the object.

[0045] In addition, the ultrasonic wave testing apparatus according to the first exemplary embodiment in the present disclosure can include an ultrasonic wave reflector 11 rotatably installed between the plurality of probes in the nozzle such that the ultrasonic waves of the probes selected from the plurality of probes 20 are transmitted to the object 1.

[0046] The ultrasonic wave reflector 11 can be made of, for example, a metal material such as stainless steel and brass, and thus can smoothly reflect ultrasonic waves and can not be corroded by a medium 2 such as water.

[0047] The ultrasonic wave reflector 11 can be fixed to a rotating shaft 12 installed through the inside of the nozzle 10, and the rotating shaft can be exposed to the outside through the side wall of the nozzle 10. A motor 13 installed outside the nozzle can be connected to one end of the rotating shaft, and thus the rotation angle of the ultrasonic wave reflector can be controlled.

[0048] As such, the rotation angle can be controlled by the motor 13, and thus the ultrasonic wave reflector 11 can selectively transmit the ultrasonic waves oscillated from the two probes 20 to the object 1.

[0049] A control process for automatically switching the frequency of the ultrasonic wave in the ultrasonic wave testing apparatus according to the first exemplary embodiment in the present disclosure will be described with reference to Figure 3

[0050] For example, in a correction generation line in a thick plate manufacturing site of a steel mill, a product that is the object 1 subjected to ultrasonic wave testing is conveyed to the ultrasonic wave testing apparatus by a guide roll 3. Before the object enters the ultrasonic wave testing apparatus, a main controller 40 constituting a manufacturing site operation system can receive thickness information of the object.

[0051] The main controller 40 can transmit the received thickness information to an on-off controller 41 for the probes.

[0052] ​The on-off controller 41 for the probes can select one of the plurality of probes 20 based on the thickness information of the object 1 to be subjected to the ultrasonic wave test according to its internal program.

[0053] When the thickness of the object 1 is, for example, 80 mm or less, a command is sent to the first pulse receiver 43 corresponding to one probe 21 oscillating ultrasonic waves having a frequency of about 5 MHz to operate the first pulse receiver 43 and stop the operation of the second pulse receiver 44 of the other probe 22.

[0054] On the other hand, when the thickness of the object 1 is, for example, more than 80 mm, a command is sent to the second pulse receiver 44 corresponding to the other probe 22 oscillating ultrasonic waves having a frequency of about 2 MHz to operate the second pulse receiver 44 and stop the operation of the first pulse receiver 43.

[0055] In addition, the main controller 40 can send the received thickness information to the direction controller 42 for the ultrasonic wave reflector.

[0056] The direction controller 42 for the ultrasonic wave reflector can control the rotation angle of the ultrasonic wave reflector by operating the motor 13 according to the sent thickness information, and switch the tilting direction of the ultrasonic wave reflector.

[0057] In other words, when the thickness of the object 1 is, for example, 80 mm or less, the tilting direction of the ultrasonic wave reflector 11 is changed so that the ultrasonic waves having a frequency of about 5 MHz oscillated from one probe 21 are reflected toward the outlet of the nozzle 10 and the lower surface of the object.

[0058] On the other hand, when the thickness of the object 1 is, for example, more than 80 mm, the tilting direction of the ultrasonic wave reflector 11 is changed so that the ultrasonic waves having a frequency of about 2 MHz oscillated from the other probe 22 are reflected toward the outlet of the nozzle 10 and the lower surface of the object.

[0059] In the ultrasonic wave testing apparatus according to the first exemplary embodiment in the present disclosure, the plurality of probes 20 oscillating ultrasonic waves having different frequencies are symmetrically installed on the nozzle 10, and by controlling the rotation angle of the ultrasonic wave reflector 11 located between the probes, so that the ultrasonic waves of the frequency selected according to the thickness of the object 1 are transmitted to the object, the frequency of the ultrasonic waves can be automatically switched according to the thickness of the object.

[0060] Therefore, in the ultrasonic wave testing apparatus according to the first exemplary embodiment in the present disclosure, the frequency of the ultrasonic waves can be easily switched and the ultrasonic waves can be stably transmitted / received.

[0061] Figure 4is a sectional view showing main parts of an ultrasonic testing device according to a second exemplary embodiment in the present disclosure, and Figure 5 is a diagram for describing a control procedure of an ultrasonic testing device according to the second exemplary embodiment in the present disclosure.

[0062] In Figure 4 and Figure 5 the second exemplary embodiment in the present disclosure differs from the first embodiment shown in Figures 1 to 3 only in the shape of the nozzle and does not have the ultrasonic reflector and the motor and the arrangement relationship of the probe, and the remaining components are the same as those of the first embodiment. Therefore, in describing the ultrasonic testing device according to the second exemplary embodiment in the present disclosure, those components which are the same as the ultrasonic testing device according to the first embodiment will be indicated with the same reference numerals, and detailed description of the configuration and function of these components will be omitted.

[0063] In the ultrasonic testing device according to the second exemplary embodiment in the present disclosure, the nozzle 10 can be formed of one exit waveguide 15 and branched from the exit waveguide, and the plurality of probes 20 can also include a plurality of entrance waveguides 14 assigned to each of the plurality of probes 20.

[0064] Each of the plurality of probes 20 can be installed inside the corresponding entrance waveguide 14, and can transmit and receive ultrasonic waves for detecting internal defects in the object 1 through the medium column 4.

[0065] As in the first embodiment described above, the probes 20 can oscillate ultrasonic waves having different frequencies. For example, one probe 21 can oscillate ultrasonic waves having a frequency of about 5 MHz, and another probe 22 can oscillate ultrasonic waves having a frequency of about 2 MHz.

[0066] Each of the probes 20 can be connected to a defect detection unit (not shown) through wired and wireless communication, which processes and calculates ultrasonic wave signals received from the object 1 to analyze whether there is an internal defect in the object.

[0067] The ultrasonic waves oscillated from the probes 20 in each entrance waveguide 14 can be propagated out of the nozzle 10 through the exit waveguide 15.

[0068] The medium 2 can also be supplied to the entrance waveguides 14 through a branch supply pipe (not shown), and then can be ejected out of the nozzle 10 through the exit waveguide 15 via a common path.

[0069] Preferably, a total reflection condition between the ultrasonic wave and the inner interface of the waveguide needs to be satisfied so that the ultrasonic wave introduced to the inlet waveguide 14 is propagated without loss in the outlet waveguide 15. That is, a loss of ultrasonic wave energy in the waveguide needs to be minimized.

[0070] To this end, as in the following Equation 2, the ultrasonic wave speed V1 in the medium in the waveguide needs to be smaller than the ultrasonic wave speed V2 in the inner interface of the waveguide.

[0071] [Equation 2]

[0072] V1 < V2

[0073] When the medium 2 such as water is filled inside the waveguide, and the inlet waveguide 14 and the outlet waveguide 15 are made of a metal material, Equation 2 can be satisfied.

[0074] In addition, since the surface is formed in an arc shape or a curved shape at a portion where a plurality of inlet waveguides 14 are coupled to one outlet waveguide 15, an angle between the ultrasonic wave and the inner interface of the waveguide is changed.

[0075] At the portion where the angle is changed, that is, at a portion where a plurality of inlet waveguides 14 are coupled to one outlet waveguide 15, described above, when the inlet waveguide and the outlet waveguide are designed so that an angle (incident angle: θ) between a propagation direction of the ultrasonic wave propagated from the inlet waveguide to the outlet waveguide and a direction perpendicular to the inner interface of the outlet waveguide is larger than a critical angle θc, the ultrasonic wave can be transmitted through the outlet waveguide without loss.

[0076] In other words, as in the following Equation 3, when the ultrasonic wave is incident on the inner interface of the waveguide at an angle θ larger than the critical angle θc, total reflection occurs.

[0077] [Equation 3]

[0078] θc < θ

[0079] Here, the critical angle can be expressed in the following Equation 4.

[0080] [Equation 4]

[0081]

[0082] Therefore, in the ultrasonic testing device according to the second exemplary embodiment in the disclosure, one outlet waveguide 15 and a plurality of inlet waveguides 14 constituting the nozzle 10 can be designed under the condition that Equations 2 and 3 described above are satisfied, and when a plurality of probes 20 selectively oscillate ultrasonic waves having different frequencies, ultrasonic testing can be performed on an object 1 having various thicknesses.

[0083] Reference will now be made to Figure 5A control procedure for automatically switching the frequency of ultrasonic waves in an ultrasonic testing apparatus according to a second exemplary embodiment in the present disclosure is described.

[0084] For example, in a calibration production line of a thick plate manufacturing site of a steel mill, a product, which is an object 1 subjected to ultrasonic testing, is conveyed to an ultrasonic testing apparatus by a guide roller 3. Before the object enters the ultrasonic testing apparatus, a main controller 40 constituting a manufacturing site operation system can receive thickness information of the object.

[0085] The main controller 40 can transmit the received thickness information to an on-off controller 41 for a probe.

[0086] The on-off controller 41 for the probe can select one of a plurality of probes 20 based on the thickness information of the object 1 subjected to ultrasonic testing according to its internal program.

[0087] When the thickness of the object 1 is, for example, 80 mm or less, a command is transmitted to a first pulse receiver 43 corresponding to one probe 21 oscillating ultrasonic waves having a frequency of about 5 MHz, to operate the first pulse receiver 43 and stop the operation of a second pulse receiver 44 of another probe 22.

[0088] On the other hand, when the thickness of the object 1 is, for example, more than 80 mm, a command is transmitted to the second pulse receiver 44 corresponding to the other probe 22 oscillating ultrasonic waves having a frequency of about 2 MHz, to operate the second pulse receiver 44 and stop the operation of the first pulse receiver 43.

[0089] In the ultrasonic testing apparatus according to the second exemplary embodiment in the present disclosure, each of the probes 20 oscillating ultrasonic waves having different frequencies can be installed on a plurality of inlet waveguides 14 of a nozzle 10, and the operation of the probes 20 can be selectively controlled so that ultrasonic waves of a frequency selected according to the thickness of the object 1 are transmitted to the object through an outlet waveguide 15, and thus the frequency of the ultrasonic waves can be automatically switched according to the thickness of the object.

[0090] Therefore, in the ultrasonic testing apparatus according to the second exemplary embodiment in the present disclosure, the frequency of the ultrasonic waves can be easily switched and the ultrasonic waves can be stably transmitted / received.

[0091] As described above, according to the present disclosure, the frequency of the ultrasonic waves can be automatically selected according to the thickness of the object, and then the ultrasonic waves can be transmitted to the lower surface of the object through the nozzle, and thus internal defects in the object having various thicknesses can be detected through one ultrasonic testing apparatus.

[0092] The spirit of the disclosure has been exemplified above. Those skilled in the art will appreciate that various modifications and changes can be made without departing from the essential spirit of the disclosure. The embodiments disclosed in this disclosure and drawings are therefore not intended to limit the spirit of the disclosure, but to describe the spirit of the disclosure. The scope of the disclosure is not limited to these embodiments. The scope of the disclosure should be interpreted by the appended claims, and all spirits equivalent to the appended claims should be interpreted as falling within the scope of the disclosure.

[0093] Industrial applicability

[0094] As described above, for example, the present disclosure facilitates performing ultrasonic testing on products manufactured in a heavy plate manufacturing site of a steel mill.

Claims

1. An ultrasonic testing device, the ultrasonic testing device comprising: A nozzle that sprays a medium toward an object to form a medium column; Multiple probes are arranged on the nozzle to vibrate ultrasonic waves; An ultrasonic reflector, rotatably mounted between the plurality of probes in the nozzle, such that ultrasonic waves from a probe selected from the plurality of probes are transmitted to the object. The ultrasonic reflector is fixed to a rotating shaft mounted inside the nozzle, and a motor mounted outside the nozzle is connected to one end of the rotating shaft. The main controller receives the thickness information of the object; An on / off controller for a probe, the on / off controller selecting a probe from a plurality of probes based on thickness information of the object sent from the main controller; A first pulse receiver and a second pulse receiver, which selectively oscillate the ultrasonic waves of their respective probes according to commands from the on / off controller for the probes; and A direction controller for an ultrasonic reflector, the direction controller controlling the rotation angle of the ultrasonic reflector by operating the motor based on the thickness information of the object sent from the main controller; The multiple probes oscillate with ultrasonic waves of different frequencies.

2. The ultrasonic testing apparatus according to claim 1, wherein, The relationship between the inner diameter d of the nozzle and the width w or diameter of the probe surface is established in the following [Equation 1]. [Formula 1] d / 2 <w<d。 3. The ultrasonic testing apparatus according to claim 1, wherein, The plurality of probes are fixedly mounted on the side wall of the nozzle at intervals from each other.

4. The ultrasonic testing apparatus according to claim 1, wherein, The ultrasonic reflector comprises a material that reflects ultrasonic waves and is not corroded by the medium.

5. The ultrasonic testing apparatus according to claim 1, further comprising: in, The nozzle is formed by an exit waveguide. Multiple inlet waveguides branch from the exit waveguide, each inlet waveguide having a plurality of probes assigned to each of the plurality of inlet waveguides.

6. The ultrasonic testing apparatus according to claim 5, wherein, The multiple probes are respectively installed inside the corresponding entrance waveguides, and The medium supplied to the inlet waveguide is ejected through the outlet waveguide.

7. The ultrasonic testing apparatus according to claim 5, wherein, The ultrasonic velocity V1 in the medium of the waveguide is smaller than the ultrasonic velocity V2 at the internal interface of the waveguide, and In the portion where the plurality of inlet waveguides are coupled to an outlet waveguide, the angle θ between the propagation direction of the ultrasonic wave from the inlet waveguide to the outlet waveguide and the direction perpendicular to the internal interface of the outlet waveguide is larger than the critical angle θc. The critical angle θc is defined by the following equation 2. [Equation 2] 8. The ultrasonic testing apparatus according to any one of claims 1, 3, 4 to 7, further comprising: A media circulation unit that forms a media column by spraying the media from the nozzle, recovers the media falling from the media column, and circulates the media back to the nozzle.

9. The ultrasonic testing apparatus according to claim 8, wherein, The medium circulation unit includes: A media receiver, which is mounted outside the nozzle and receives the media falling from the media column; A recycling tube, which is connected to the medium receiver; A supply pipe that supplies the medium from the recovery pipe to the nozzle; and A circulation pump is installed between the recovery pipe and the supply pipe to provide injection pressure to the nozzle.

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