Patent Application
20180340914
The present disclosure relates to the detection of internal flaws in steel plates using an ultrasonic sensor.
In thick steel plate manufacturing plants of steel mills, an ultrasonic detection process is performed on a pre-shipment product correction line so as to detect internal flaws in steel plate products. Ultrasonic detection is a method of detecting flaws (defects) such as cracks, inclusions, or segregation of steel plates by transmitting ultrasonic waves to the steel plates, receiving ultrasonic waves reflected from the steel plates, and analyzing the received ultrasonic waves.
Whether an ultrasonic sensor (probe) is brought into contact with a surface of a steel plate, ultrasonic detection methods may be classified as a contact type or a non-contact type.
In the case of a contact-type detection method, detection errors are frequent because of noise relating to the surface state and shape of steel plates, and because of friction between an ultrasonic sensor and a steel plate, the detection surface of a probe wears, thereby decreasing the performance of detection and the lifespan of probes.
To address these problems relating to contact-type detection methods, non-contact-type detection methods have been considered in various aspects.
Non-contact-type detection methods require a contact medium to transmit the energy of ultrasonic waves generated by an ultrasonic sensor (probe) to a steel plate, and a typical example thereof is water having high ultrasonic wave transmission efficiency.
As illustrated in
In the related art, only the ultrasonic sensor 1 and the medium sprayed toward the lower portion of the detection target object 3 are disclosed, but a specific configuration for detecting internal flaws in the detection target object 3 is not disclosed.
Japanese Utility Model Application Laid-open Publication No. S63-200161 (Publication date: Dec. 23, 1988) is a related-art document.
Aspects of the present disclosure may provide a device and method for easily detecting internal flaws of steel plates using a height-adjustable ultrasonic sensor.
According to an aspect of the present disclosure, a device for detecting an internal flaw in a steel plate using a height-adjustable ultrasonic sensor may include: a spray nozzle provided at a distance from a lower portion of a steel plate and configured to spray a medium toward the steel plate to form a medium column; an ultrasonic sensor configured to transmit and receive ultrasonic waves for detecting an internal flaw in the steel plate through the medium column; a flaw detecting unit configured to detect the internal flaw in the steel plate based on the transmitted and received ultrasonic waves; and a lifting unit configured to lift or lower the ultrasonic sensor to adjust the distance between the ultrasonic sensor and the steel plate such that waves reflected by a lower surface of the steel plate, waves reflected by the internal flaw of the steel plate, and waves reflected by an upper surface of the steel plate may arrive at the ultrasonic sensor sequentially.
According to another aspect of the present disclosure, a method for detecting an internal flaw in a steel plate using a height-adjustable ultrasonic sensor may include: forming a medium column by spraying a medium toward a steel plate using a spray nozzle provided at a distance from a lower portion of the steel plate; transmitting and receiving ultrasonic waves for detecting an internal flaw in the steel plate through the medium column by using an ultrasonic sensor; and detecting the internal flaw in the steel plate based on the transmitted and received ultrasonic waves by using a flaw detecting unit, wherein the ultrasonic sensor may be lifted or lowered to adjust the distance between the ultrasonic sensor and the steel plate such that waves reflected by a lower surface of the steel plate, waves reflected by the internal flaw of the steel plate, and waves reflected by an upper surface of the steel plate may arrive at the ultrasonic sensor sequentially.
According to one or more embodiments of the present disclosure, the distance between an ultrasonic sensor and a steel plate may be adjusted according to the thickness of the steel sheet, such that waves reflected by a lower surface of the steel plate, waves reflected by an internal flaw of the steel plate, and waves reflected by an upper surface of the steel plate may arrive at the ultrasonic sensor sequentially. Thus, the internal flaw in the steel plate may be easily detected.
Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the embodiments of the present disclosure may be modified in various forms, and the scope of the present disclosure is not limited to the embodiments. In the drawings, the shapes and dimensions of elements may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like elements.
Referring to
The spray nozzle 110 may be provided below a steel plate 3, which is being transferred, for example, using rolls 4, and may form a medium column 10 (such as a water column) by spraying a medium (such as water) toward the steel plate 3. The medium column 10 may have a height of several tens of millimeters (mm) from a nozzle hole of the spray nozzle 110 to enable stable transmission and reception of ultrasonic waves.
The ultrasonic sensor 120 is provided inside the spray nozzle 110, and configured to transmit and receive ultrasonic waves for detecting internal flaws in the steel plate 3 through the medium column 10. The ultrasonic sensor 120 may be supported and moved upwardly and downwardly by the lifting unit 150 placed under the ultrasonic sensor 120 and may include an immersion type probe configured to be immersed in the medium. The ultrasonic sensor 120 is wired or wirelessly connected to the flaw detecting unit 160 configured to process and calculate ultrasonic wave signals received from the steel plate 3 for analyzing whether the steel plate 3 has an internal flaw. In the case of a wireless connection, the ultrasonic sensor 120 includes a wireless communication module therein to wirelessly transmit ultrasonic wave signals to the flaw detecting unit 160.
The medium circulating unit 130 collects the medium falling from the medium column 10 and circulates the collected medium to the spray nozzle 110.
According to the embodiment of the present disclosure, the medium circulating unit 130 includes a medium receiver 131, a collection tube 132, and a supply tube 133.
The medium receiver 131 is provided around the spray nozzle 110 to receive the medium falling from the medium column 10.
The medium receiver 131 may have a cylinder or box shape confining the spray nozzle 110.
The collection tube 132 is connected to the medium receiver 131 and configured to collect the medium from the medium receiver 131. The medium falling from the medium column 10 to the medium receiver 131 is supplied to the collection tube 132.
A filter 134 may be installed in the collection tube 132 to filter the medium discharged from the medium receiver 131, and thus the medium may be supplied back to the spray nozzle 110 after impurities are removed from the medium.
The supply tube 133 is provided to supply the medium from the collection tube 132 to the spray nozzle 110, and to this end, the supply tube 133 communicates with both the spray nozzle 110 and the collection tube 132.
A spray pressure supply unit 140 may be provided between the supply tube 133 and the collection tube 132 to supply spray pressure to the spray nozzle 110. Since the spray pressure supply unit 140 supplies pressure to the spray nozzle 110, the spray nozzle 110 may spray the medium at constant pressure for forming the medium column 10. A circulation pump may be used as the spray pressure supply unit 140, and the spray pressure of the spray nozzle 110 may be controlled by controlling the circulation pump.
The lifting unit 150 is configured to support the ultrasonic sensor 120 and lift or lower the ultrasonic sensor 120 under the control of the flaw detecting unit 160 such that the distance between the steel plate 3 and the ultrasonic sensor 120 may be adjusted. For example, a hydraulic cylinder may be used as the lifting unit 150. However, any other device such as a rack-pinion gear unit may be used to lift and lower the ultrasonic sensor 120.
The flaw detecting unit 160 operates the ultrasonic sensor 120 to transmit and receive ultrasonic waves and thus to detect flaws in the steel plate 3. In addition, the flaw detecting unit 160 may receive information regarding the thickness of the steel plate 3 and may control the lifting unit 150 to lift or lower the ultrasonic sensor 120 according to the information regarding the thickness of the steel plate 3, thereby adjusting the distance between the steel plate 3 and the ultrasonic sensor 120. This will be described below with reference to
In addition,
As shown in
In addition,
First, as illustrated in
In the embodiment of the present disclosure, the ultrasonic wave signal reflected from the upper surface of the steel plate 3 and rereflected by the ultrasonic sensor 120 is relatively weak and thus negligible, and thus, the ultrasonic wave signal is not used for detecting internal flaws in the steel plate 3 (that is, negligible).
In addition,
Referring to
In addition, S11 is an ultrasonic wave signal appearing as the ultrasonic wave signal S0 is reflected from the upper surface of the steel plate 3 back to the ultrasonic sensor 120, S21 is an ultrasonic wave signal appearing as the ultrasonic wave signal S1 is reflected from the upper surface of the steel plate 3 back to the ultrasonic sensor 120, and S31 is an ultrasonic wave signal appearing as the ultrasonic wave signal S3 is reflected from the upper surface of the steel plate 3 back to the ultrasonic sensor 120.
In addition, as expressed by Condition 1 below, Δts is a period of time taken for an ultrasonic wave signal, having passed through the lower surface of the steel plate 3, to be reflected from the upper surface of the steel plate 3 back to the lower surface of the steel plate 3, and as expressed by Condition 2 below, Δtw is a period of time taken for an ultrasonic wave signal, to be reflected from the lower surface of the steel plate 3 back to the ultrasonic sensor 120.
Δts=2H×Vs [Condition 1]
where H is the distance from the surface of the ultrasonic sensor to the steel plate, and Vs is the velocity of ultrasonic waves in the steel plate.
Δtw=2T×Vw [Condition 2]
where T is the thickness of the steel plate, and Vw is the velocity of ultrasonic waves in the medium (water).
In addition,
As illustrated in
Δtw<Δts [Condition 3]
The distance H between the steel plate S and the ultrasonic sensor 3 satisfying Condition 3 may be expressed by Condition 4 below by substituting Conditions 1 and 2 into Condition 3 and rearranging Condition 3.
where H is the distance between the ultrasonic sensor and the steel plate, T is the thickness of the steel plate, Vs is the velocity of ultrasonic waves in the steel plate, and Vw is the velocity of ultrasonic waves in the medium (water).
That is, the flaw detecting unit 160 may control the lifting unit 150 to lift or lower the ultrasonic sensor 120 so as to adjust the distance between the ultrasonic sensor 120 and the steel plate 3 according to Condition 4 above. In this manner, the waves S1, S2, and S2 reflected by the lower surface of the steel plate 3, the waves S12, S22, and S32 reflected by the internal flaw of the steel plate 3, and the waves S11, S21, and S31 reflected by the upper surface of the steel plate 3 may sequentially arrive. In this case, the magnitudes of the ultrasonic wave signals are as follows: S1>S12>S11, S2>S22>S21, and S3>S32>S31, and thus when the magnitude of the waves S12, S22, and S32 reflected by the internal flaw of the steel plate 3 is between the magnitude of the waves S1, S2, and S2 reflected by the lower surface of the steel plate 3 and the magnitude of the waves S11, S21, and S31 reflected by the upper surface of the steel plate 3, the flaw detecting unit may determine that the steel plate 3 has an internal flaw.
However, if the distance H between the ultrasonic sensor 120 and the steel plate 3 is too small as compared to the thickness of the steel plate, it is difficult to detect internal flaws.
That is, as illustrated in
Therefore, according to the embodiment of the present disclosure, the distance between the ultrasonic sensor 120 and the steel plate 3 is adjusted such that the waves S1, S2, and S2 reflected by the lower surface of the steel plate 3, the waves S12, S22, and S32 reflected by the internal flaw of the steel plate 3, and the waves S11, S21, and S31 reflected by the upper surface of the steel plate 3 may sequentially arrive, and flaws are detected based on the magnitudes of the ultrasonic wave signals. Thus, the internal flaw of the steel plate 3 may be easily detected.
In addition,
Like in the previous embodiment, the ultrasonic detecting device of the embodiment may include a spray nozzle 210, ultrasonic sensors 220, a medium circulating unit 230, and a spray pressure supply unit 240.
In
According to the embodiment of the present disclosure, the ultrasonic sensors 220 are arranged in a width direction of a steel plate 3, thereby forming a probe array 225. The probe array 225 may have a length L equal to or greater than a width W of the steel plate 3. The spray nozzle 210 accommodates the probe array 225, and in the embodiment of the present disclosure, the spray nozzle 210 is illustrated as having a tetragonal cross-sectional shape with a length in the width direction of the steel plate 3. In addition, it is illustrated that a medium receiver 231 also has a tetragonal box shape confining the outside of the spray nozzle 210. In the embodiment of the present disclosure, however, the spray nozzle 210 and the medium receiver 231 are not limited to the above-described shapes. That is, the spray nozzle 210 and the medium receiver 231 may have other various shapes.
According to the embodiment of the present disclosure, since a plurality of probes 220 arranged in the width direction of the steel plate 3 cover the entire width of the steel plate 3, a detecting process may be performed on the entire width of the steel plate 3 while the steel plate 3 is transferred.
As described above, according to the embodiment of the present disclosure, the distance between the ultrasonic sensors 220 and the steel plate 3 may be adjusted according to the thickness of the steel sheet such that waves reflected by a lower surface of the steel plate 3, waves reflected by an internal flaw of the steel plate 3, and waves reflected by an upper surface of the steel plate 3 may sequentially arrive. Thus, internal flaws of the steel plate 3 may be easily detected.
In addition,
Hereinafter, with reference to
Referring to
Next, the ultrasonic sensor 120 may transmit and receive ultrasonic waves through the medium column 10 so as to detect an internal flaw in the steel plate 3 (S602). The ultrasonic sensor 120 may be supported and moved upwardly and downwardly by the lifting unit 150 placed under the ultrasonic sensor 120 and may include an immersion type probe configured to be immersed in the medium.
Next, the flaw detecting unit 160 may detect an internal flaw in the steel plate 3 based on the transmitted and received ultrasonic waves (S603).
Specifically, the flaw detecting unit 160 may easily detect an internal flaw in the steel plate 3 based on the magnitudes of sequentially arriving ultrasonic wave signals.
In this case, according to the embodiment of the present disclosure, the flaw detecting unit 160 is configured to control the lifting unit 150 according to information regarding the thickness of the steel plate 3 to lift or lower the ultrasonic sensor 120 and thus to adjust the distance between the steel plate 3 and the ultrasonic sensor 120. Owing to this configuration, waves S1, S2, and S2 reflected by a lower surface of the steel plate 3, waves S12, S22, and S32 reflected by an internal flaw of the steel plate 3, and waves S11, S21, and S31 reflected by an upper surface of the steel plate 3 may arrive sequentially, and flaws may be detected based on the magnitudes of the ultrasonic wave signals arriving sequentially. Thus, the internal flaw of the steel plate 3 may be easily detected.
In the description of the present disclosure, a component denoted with a term such as “˜ unit” or “˜ er/or” may be implemented as a hardware component, a software component, and/or a combination of hardware and software components. For example, such a component may be implemented with at least one general-purpose or special-purpose computer such as a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), a programmable logic unit (PLU), a microprocessor, or any other device capable of performing an instruction and responding to the instruction.
In addition, software may include a computer program, a code, an instruction, or a combination of at least one thereof. In addition, processing devices may be configured to operate in a desired manner and may be independently or collectively instructed. Software and/or data may be permanently or temporarily embodied in a certain machine, a component, a physical device, virtual equipment, a computer storage medium or device, or propagating signal waves so as to be interpreted by a processing device or provide instructions or data to the processing device. Software may be distributed over network coupled computer systems and may be stored and executed in a distributed fashion. Software and data may be stored in at least one computer-readable recording medium.
As described above, according to the one or more of the above embodiments of the present disclosure, the distance between the ultrasonic sensor and a steel plate may be adjusted according to the thickness of the steel sheet such that waves reflected by a lower surface of the steel plate, waves reflected by an internal flaw of the steel plate, and waves reflected by an upper surface of the steel plate may sequentially arrive. Thus, internal flaws in the steel plate may be easily detected.
The scope of the present disclosure is not limited to the above-described embodiments and the accompanying drawings. It will be apparent to those skilled in the art that various replacements, modifications, and variations could be made without departing from the scope of the present invention as defined by the appended claims.
The above-described embodiments of the present disclosure may be useful to detect internal flaws of steel plates after a final production process in steel mills.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2015-0173392 | Dec 2015 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2015/014093 | 12/22/2015 | WO | 00 |
