KR101105107B1 - Eddy Current Surface-defect On-Line Detection Device for Hot Wire Rod - Google Patents

Abstract

The present invention relates to an apparatus and method for performing eddy current flaw detection online by quenching the surface of a hot wire during transfer to bring the temperature of the surface defect portion of the wire to be below the magnetic transformation point of the wire. The present invention provides cooling means for cooling the surface portion of the hot wire rod being transferred; Temperature detection means for detecting a surface temperature of the wire rod from the cooling means by a predetermined distance (L1) in the conveying direction of the wire rod; Control means for outputting an eddy current flaw detection start signal when the surface temperature T1 detected by the temperature detection means 50 is higher than the magnetic transformation point T2 of the wire rod; Spaced apart from the cooling means by a predetermined distance (L2) in the conveying direction of the wire rod, when an eddy current flaw detection start signal is received from the control means generates an eddy current on the surface of the wire rod and the surface of the temperature below the magnetic transformation point (T2) Signal detecting means for detecting a surface defect signal by detecting a change in eddy current due to the defect; And signal processing means for analyzing the detected surface defect signal to determine the surface defect of the hot wire. According to the present invention, by checking the surface defect status of the wire rod product in real time, quality control can be performed in real time to prevent the occurrence of a large amount of quality defects, and accurately detect continuous and periodic scratch defects, overlap defects and capacitive defects can do.

Hot, Wire, Defects, Eddy Currents, Scanning, Online, Cooling, Magnetostriction, Overlap, Scap

Description

Eddy Current Surface-defect On-Line Detection Device for Hot Wire Rod}

1 is a schematic diagram showing an example of a production process line of a wire rod to which the present invention is applied.

Figure 2 is a schematic diagram of the configuration of the hot wire surface defect online eddy current flaw detector according to an embodiment of the present invention.

Figure 3 is a cross-sectional view of the inlet, outlet sleeve guide coupled to the temperature detection means according to an embodiment of the present invention.

4 is a detailed view of the inlet sleeve guide shown in FIG. 3.

5 is a cross-sectional view of the cooling means according to an embodiment of the present invention.

6 is an exemplary view for explaining the cooling operation of the cooling means according to an embodiment of the present invention.

7 is a view schematically showing the cooling position, the temperature detection position and the eddy current flaw detection position of the on-line eddy current flaw detector according to an embodiment of the present invention.

FIG. 8 is a diagram illustrating temperature characteristics of parts of a hot wire rod applied in FIG. 7.

9 is a view showing the results of eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 770 ℃.                 

10 is a view showing the results of conducting eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 800 ℃.

11 is a view showing the results of the eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 1010 ℃.

12 is a view showing the results of the eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 1010 ℃.

13 is a view showing the results of the eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 790 ℃.

14 is a view showing the result of performing the eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 1010 ℃.

15 is a view showing the results of performing the eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 790 ~ 800 ℃.

16 is a view showing the results of conducting eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 790 ~ 800 ℃.

17 is a view showing the results of conducting eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 790 ~ 800 ℃.

18 is a view showing the result of performing eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 810 ℃.

19 is a view showing the results of eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 830 ℃.                 

20 is a view showing the results of eddy current inspection of the rolled wire when the surface temperature of the hot wire according to an embodiment of the present invention is about 850 ℃.

 Explanation of symbols on the main parts of the drawings

50: temperature detection means 51: control means

60: hot wire 100: cooling means

101: guide to 103,103 ': squirting nozzle

110: fixed base 150: electric motor

200: signal detection means 210: signal processing means

300: speed detection means 410,420: inlet and outlet sleeve guide

411: Temperature detection hole

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an online complete flow flaw detection apparatus and method for hot wire rods, and more particularly, to an eddy current by performing eddy current flaw detection by cooling the surface of a hot wire rod during transfer to carry out eddy current flaw detection at a temperature of the surface defect portion of the wire rod below the magnetic transformation point of the wire rod. The present invention relates to an apparatus and method for eddy current flaw detection of hot wire surface defects on-line by using a permeability variation of a wire.

In general, a method of measuring wire surface defects using eddy currents has been used as a conventional hot wire surface defect inspection technique. In this eddy current measurement method, a magnetic field such as a solenoid is formed in an alternating current coil, and when a wire that is a conductor passes through the magnetic field of the coil, a magnetic field generated in the coil acts on the wire.

The magnetic field of the coil is generated by alternating current, and the direction of the magnetic field passing through the wire is changed in time. At this time, the wire rod generates a loss current called eddy current in the circumferential direction of the wire rod due to the magnetic field formed in the traveling direction of the wire rod. The eddy current disturbs the magnetic field of the coil and modulates the circuit current. The change of the circuit current due to such disturbance is measured to determine whether there is a surface defect present on the surface of the hot wire.

The magnitude and distribution of eddy currents in the wire rod are changed by defects such as frequency, conductivity and permeability of the wire rod, size and shape of the wire rod, coil shape and size, current, and distance cracking between the wire rod. Therefore, by detecting a change in the eddy current flowing in the wire rod, it is possible to measure the presence or absence of surface defects present in the wire rod.

When measuring surface defects of wire rod through this eddy current test method, it is impossible to detect continuous scratches or continuous overlap defects due to the principle of differential coil detecting the difference between two secondary coils. Although attempts to detect wire surface defects by inspection methods have a long history, it is common to those skilled in the art or to those who detect surface defects of wire rods that it is almost impossible to detect minute mark defects that periodically appear on the wire surface. to be.

In addition, in the wire rod inspection method which proceeds at high speed, the distance between the wire rod and the coil is present as one of the measurement variables. However, the wire rod is vibrated, so that the reliability of the wire defect measurement value is low.

On the other hand, in addition to the eddy current inspection method, there is a method for measuring the surface defects of the wire rod using a radiation thermometer to measure the radiation temperature of the wire surface. The method of measuring the radiation temperature of the wire rod surface is a method of directly monitoring the surface temperature of the wire rod after the water cooling process using several radiation thermometers.The radiation thermometer is installed perpendicular to the direction of the wire rod. Radiation thermometer is used to measure the change of wire surface temperature.

This conventional method is susceptible to the vibration of the wire rod because the wire rod is likely to be out of the focus of the radiation thermometer during the wire rolling vibration during wire rolling, and the signal caused by the minute defects by using the radiation thermometer with one pixel S / N (signal-to-caught) ratio is low because it is averaged with the peripheral signal, and thus there is a disadvantage that the overall defect detection rate is lowered as well as the minute defects.

In general, the detection of surface defects of wire rods in the wire rod rolling process includes the eddy current inspection method and the surface defect detection method of the radiation thermometer. The lack of successful cases of flaw detection is a common perception amongst those skilled in the art.

Therefore, the surface defect inspection of most wire rolling processes is in a form that relies heavily on the inspection of the appearance of the wire products of the workers who inspect the wire surface defects, and the surface defect on-line eddy current flaw detection technology for hot wire with high reliability This has been a very urgent task.

The present invention has been proposed to solve the above problems, the eddy current inspection is performed by the surface defects to become the magnetic transformation region of the wire rod in the process of quenching the surface of the high temperature wire rod product after the wire rolling process to reheat to the internal heat of the wire rod product Accordingly, an object of the present invention is to provide a hot wire surface defect online eddy current flaw detector and method for online inspection of surface defects of hot wire by using permeability variation of eddy current.

Another object of the present invention is to provide a hot wire surface defect on-line eddy current inspection apparatus and method capable of accurately detecting continuous scratch defects, scab coupling, and over-lap defects that could not be realized with conventional eddy current inspection systems. have.

It is still another object of the present invention to provide a hot wire surface defect on-line eddy current inspection apparatus and method for improving the reliability of wire defect measurement values by preventing vibration of the wire which proceeds even at the time of high speed wire surface defect inspection. .

On-line eddy current flaw detection device for hot wire surface defects according to the present invention for achieving the above object, the cooling means for cooling the surface portion of the hot wire during transport; Temperature detection means for detecting a surface temperature of the wire rod from the cooling means by a predetermined distance (L1) in the conveying direction of the wire rod; Control means for outputting an eddy current flaw detection start signal when the surface temperature T1 detected by the temperature detection means 50 is higher than the magnetic transformation point T2 of the wire rod; Spaced apart from the cooling means by a predetermined distance (L2) in the conveying direction of the wire rod, when an eddy current flaw detection start signal is received from the control means generates an eddy current on the surface of the wire rod and the surface of the temperature below the magnetic transformation point (T2) Signal detecting means for detecting a surface defect signal by detecting a change in eddy current due to the defect; And signal processing means for analyzing the detected surface defect signal to determine the surface defect of the hot wire.

In one embodiment of the present invention, the eddy current flaw detector according to the present invention, the mouth, respectively installed on the left and right sides of the signal detection means to guide the hot wire during transfer and attenuate the vibration of the signal detection means, It may further include an outlet flaw sleeve guide, the temperature detection hole is drilled in the upper portion of the inlet flaw sleeve guide to the signal detection means to measure the surface temperature of the wire guided through the temperature detection hole.

In addition, in one embodiment of the present invention, the eddy current flaw detector according to the present invention, the speed sensing means for detecting the feed speed of the wire rod; And driving means for moving a predetermined member fixed to the cooling means according to the sensed speed.

Here, in one embodiment of the present invention, the cooling means according to the present invention is to cool the hot wire of 900 ℃ or more to 700 ℃ or less and when the surface temperature of the wire detected by the temperature detection means is 790 ~ 800 ℃, the It is preferable that the signal detection means detects a surface defect signal by generating an eddy current on the surface of the wire rod and detecting a change in the eddy current caused by a surface defect of 770 ° C. or less.

In addition, the hot wire surface defect on-line eddy current flaw detection method according to the present invention for achieving the above object, the cooling step of cooling the surface portion of the hot wire during transfer; A temperature detection step of detecting a surface temperature of the wire rod at a position spaced apart by a predetermined distance (L1) from the point where the cooling is completed; A detection start signal outputting step of determining whether the detected surface temperature (T1) is higher than the magnetic transformation point (T2) of the wire rod and outputting an eddy current test start signal when the T1 is higher than T2; When the eddy current flaw detection start signal is received, an eddy current is generated on the surface of the wire rod at a position spaced by a predetermined distance (L2) at the point where the cooling is completed, and an eddy current due to a surface defect of a temperature below the magnetic transformation point (T2). A signal detection step of detecting a surface defect signal by detecting a change in the signal; And a signal processing step of determining the surface defect of the wire rod by analyzing the detected surface defect signal.

In one embodiment of the present invention, the eddy current flaw detection method according to the present invention, the step of measuring the feed rate of the wire; And changing the distances L1 and L2 according to the measured feed rate.

In addition, in one embodiment of the present invention, the eddy current flaw detection method according to the present invention, the step of changing the distance (L1, L2) in accordance with the surface temperature (T1) of the wire rod detected in the temperature detection step. It may be included as.

The present invention provides an apparatus and method for online eddy current inspection of wire rods in a hot state with their surface defects. In particular, after the wire rod rolling process, the surface of the high temperature wire product is quenched with cooling water so that the surface defect becomes the magnetostriction region of the wire rod and the eddy current inspection is performed in the magnetic transformation zone of the wire rod during the reheating to the internal heat of the high temperature wire rod product. The on-line surface defect eddy current flaw detector and method for hot wire products with high reliability by using permeability distortion of the

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, detailed descriptions of preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the same reference numerals and the same elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a schematic diagram showing an example of a production process line of a wire rod to which the present invention is applied. Referring to FIG. 1, the hot wire surface defect online eddy current flaw detector 500 according to the present invention is positioned between the finishing mill 10 and the water cooling process 40. In more detail, in the wire rod rolling process, the wire rod 60 is drawn out from the finishing mill 10 and the surface defect is detected by the eddy current flaw detector 500 according to the present invention, followed by a pinch through the water cooling process 40. The wire 30 is drawn in and rolled into the roll 30.

Figure 2 is a schematic diagram of the configuration of the hot wire surface defect online eddy current flaw detector according to an embodiment of the present invention. As shown in FIG. 2, the hot wire surface defect online eddy current flaw detector 500 according to the present invention includes cooling means 100 for cooling the surface portion of the hot wire 60 being transferred, from the cooling means 100. The temperature detecting means 50 for detecting the surface temperature of the wire rod 60 and the surface temperature T1 detected by the temperature detecting means 50 are spaced apart by a predetermined distance L1 in the conveying direction of the wire rod. If higher than the magnetic transformation point (T2) of the control means 51 for outputting the eddy current flaw detection start signal, is separated from the cooling means 100 by a predetermined distance (L2) in the conveying direction of the wire rod, from the control means (51) A signal detecting means for generating an eddy current on the surface of the wire rod 60 and detecting a surface defect signal by detecting a change in eddy current due to a surface defect at a temperature below the magnetic transformation point T2 when an eddy current flaw detection start signal is received ( 200) and And a signal processing means 210 for analyzing the detected surface defect signal to determine the surface defect of the hot wire.

In one embodiment of the present invention, the eddy current flaw detector 500 according to the present invention, respectively installed on the left and right sides of the signal detection means 200 and the hot wire in the transfer of the signal detection means 200 It may further include an inlet and outlet flaw sleeve guide 410, 420 to guide to and attenuate the vibration of the signal detecting means 200.

In addition, in another embodiment of the present invention, the eddy current flaw detector 500 according to the present invention, the speed detecting means 300 for detecting the feed speed of the wire rod 60 and the cooling according to the detected speed It may further comprise a drive means 150 for moving the predetermined member fixed to the means (100). In this case, the driving means 150 may operate in response to the surface temperature T1 detected by the temperature detecting means 50.

2 shows an eddy current flaw detector 500 according to an embodiment of the present invention, but is also shown in the drawings with additional members that depart from the spirit of the present invention. It is noted here that such elements can be more specifically realized in embodiments of the present invention.

As shown in FIG. 2, the cooling means 100 of the eddy current flaw detector 500 according to the present invention is preferably an apparatus capable of uniformly cooling the surface of the hot wire 60. As illustrated in the figure, the cooling means 100 is fixed to the movable base 120 to move forward and backward from the fixed base 110, the movable base between the movable base 110 and the movable base 120 A screw drive gear for moving the cooling means 100 by rotating the screw 140 at one end of the screw 140 is combined with a screw 140 for moving the 120 and a screw nut hole 130 ( 160 and the combination of the pinion of the electric motor 150 in accordance with the rotation of the electric motor 150, the cooling device 100 is moved to the front of the eddy current flaw sensor 200. In addition, the electric motor 150 may be controlled according to the signal of the speed detecting means 300 for detecting the feed speed of the wire rod (60). That is, when the feed speed of the wire rod 60 is fast, the electric motor 150 is driven so that the cooling means 100 moves in the direction opposite to the feed direction of the wire rod 60, and the feed speed of the wire rod 60 is reversed. If it is slow, the electric motor 150 is driven to move the cooling means 100 in the conveying direction of the wire rod (60).                     

Meanwhile, the inlet / outlet flaw sleeve guides 410 and 420 are installed at the left and right sides of the signal detecting means 200, respectively, to fix the signal detecting means 200, and simultaneously signal the hot wire 60 being transferred. It guides to the detection means 200 and attenuates the vibration of the signal detection means 200. Before and after the inlet / outlet flaw sleeve guides 410 and 420, the inlet / outlet roller guides 400 and 401 for attenuating the vibration of the moving wire 60 are disposed.

In one embodiment of the present invention, the temperature detecting hole 411 in the circumferential direction of the inlet sleeve guide 410 of the signal detecting means 200, the temperature detecting means 50 is the temperature detecting hole ( The temperature of the rolled material passing through the inlet sleeve guide 410 may be detected through 411. This can eliminate the influence of the external environment when detecting the surface temperature. However, the temperature detection hole 411 is presented as an embodiment of the present invention and the temperature detecting means 50 according to the present invention may detect the surface temperature of the wire 60 through the temperature detection hole 411. However, surface temperature can be detected at other locations.

3 is a cross-sectional view of the inlet and outlet sleeve guides coupled to the temperature detecting means according to an embodiment of the present invention, and FIG. 4 is a detailed view of the inlet sleeve guide shown in FIG. Referring to FIGS. 3 and 4, the inlet sleeve guide 400 according to the present invention has a mouth 413 for guiding the rolled hot wire 60 safely and an inner surface for attenuating some vibration of the wire 60. It is composed of a guide inner surface 415 which is circular. Temperature guide hole 411 of the long hole in the circumferential direction in the guide inner surface 415 is configured to see the rolled material proceeding from the outside of the guide 410 to the guide furnace 414 of the guide inner surface 415 The sleeve guide 410 is configured.

In the outer portion of the inlet sleeve guide 410 is formed a guide cooling unit 412 consisting of a curved guide step and the outer portion is configured to enable the inlet sleeve guide 410 by cooling water.

As shown in FIG. 3, the temperature detecting means 200 is fixed by the inlet / outlet sleeve guides 410 and 420, and the temperature detecting hole 411 formed in the inlet sleeve guide 410 is the flaw detector 200. It is configured to be placed in the minimum proximity from the. The inlet / outlet sleeve guides 410 and 420 are fixed by the guide base 430 and the clamps 440 and 441. Cooling water is supplied through the coolant hole 431 of the guide base 430 to cool the inlet / outlet sleeve guides 410 and 420.

On the other hand, the cooling means 100 for uniformly cooling the surface of the rolled wire 60 in an annular shape is a very important component in the present invention. That is, the surface of the rolled wire rod 60 having an annular cross section must be uniformly cooled so that the surface of the wire rod such as scab defects, scratches, overlap defects, mark defects, etc. can be removed from the surface of the rolled material. The minute surface defect temperature causes a difference from the temperature of the top portion, which enables eddy current inspection of hot wire surface defects with high reliability.

5 is a cross-sectional view of the cooling means according to an embodiment of the present invention, Figure 6 is an exemplary view for explaining the cooling operation of the cooling means according to an embodiment of the present invention. First, referring to FIG. 5, the cooling means 100 according to the present invention includes a guide furnace 101 composed of an annular inner wall surface 102 through which a rolled wire rod 60 passes, and the guide furnace 101 direction. The entrance nozzle 103 and the exit nozzle 103 'having a predetermined angle θ are formed in an annular shape, and the two cooling nozzles 103 and 103' are oriented in the entrance nozzle 103 of the cooling means 100. ) And the exit nozzle 103 'are configured to face each other at the same angle, and the entrance nozzle supply chamber 104 and the exit nozzle supply supply the high pressure cooling water to the entrance nozzle 103 and the exit nozzle 103'. A room 104 'is formed to communicate with the high-pressure water inlets 108 and 108', respectively, and a discharge inlet 107 through which coolant is discharged at the top of the inner wall 102 of the central portion of the guide furnace 101. ) Is formed and an annular discharge space 105 is formed in communication with the discharge inlet 107, and this discharge is performed. It has an exhaust outlet 106 to which cooling water is discharged at the bottom of the shaft 105.

The gap G between the inlet nozzle 103 and the outlet nozzle 103 'of the cooling means 100 illustrated in FIG. 5 forms a sufficient jetting column of the coolant sprayed through the nozzle to cool the coolant inside the guide furnace 101. It is preferable that the filling and holding are performed, but the interval G between the entry / exit nozzles 103 and 103 'is preferably 1.5 to 2 mm.

An example of the cooling operation of the cooling means 100 described above will be described with reference to FIG. 6. As shown in FIG. 6, high-pressure water is supplied from the inlets 108 and 108 ′ of the cooling means 100 according to the present invention, and a high-temperature rolling material is provided inside the guide furnace 101 of the cooling device 100. When passing through, the high-pressure water is ejected at high speed in the advancing direction of the rolled material 100 in the entry nozzle 103, while the high-speed jet in the opposite direction of the progress of the rolled wire 60 in the exit nozzle 103 'cooling means Cooling water collides between the entry nozzle 103 and the exit nozzle 103 ′ of the 100 to fill the cooling water inside the guide furnace 101, and through the discharge inlet 107 formed at the upper end of the guide furnace 101. Cooling water discharge

As described above, since the state of the cooling water is maintained between the guide furnace 101, the entry nozzle 103 and the exit nozzle 103 'of the cooling means 100, the outer portion of the hot wire 60 of high temperature contacts the cooling water. The time and the coolant contact area are the same so that the surface portion of the hot wire is cooled uniformly.

Here, the ejection angle of the entry nozzle 103 and the exit nozzle 103 'of the cooling means 100 of the present invention is preferably approximately 60 degrees, and if the angles of the two nozzles 103 and 103' are smaller than 45 degrees, the cooling water The ejection distance of the cooling water jetting column is reduced while the contact distance of the cooling water is shortened, so that the coolant filling the inside of the guide furnace 101 destroys the cooling water jetting column ejected from the two nozzles 103 and 103 '. (101) Since the phenomenon is discharged to the bottom of the inlet and outlet, the bottom portion of the rolled wire 60 penetrating the lower portion of the guide furnace 101 is in contact with the coolant than the upper surface of the rolled wire to increase the time of the rolled material Uniform cooling is not achieved. In addition, when the angle of the inlet and outlet nozzles 103 and 103 'is greater than 75 °, the ejection distance of the coolant is shortened, so that the contact distance between the coolant and the outlet nozzle 103' is increased, but the coolant is long. While the ejection power of the ejection column is large, a part of the ejection column of the strongly ejected cooling water is inverted in the inlet and outlet directions of the cooling means 100 to be in irregular contact with the rolled material, so that the rolling wire penetrates below the guide furnace 101. Uniform cooling is not achieved.

FIG. 7 is a view schematically showing a cooling position, a temperature detection position, and an eddy current flaw detection position of an on-line eddy current flaw detector according to an embodiment of the present invention, and FIG. 8 shows temperature characteristics of each part of the hot wire applied in FIG. 7. One drawing. 7 and 8 will be described with reference to the preferred embodiment of the action of the hot wire surface defect online eddy current flaw detector according to the present invention.

Referring to the drawings, in the present invention, the surface portion of the hot wire 60, which is approximately 900 ° C. or more, passing through the cooling means 100 is quenched and reheated to an internal heat source of the rolled wire 60. When the surface temperature is higher than the magnetic transformation point temperature of the wire rod 60 (approximately 770 ° C.), the temperature of the surface defects such as scap defects, mark defects, over-lap defects, scratched defects, etc. present on the surface of the rolled wire rod 60. Is below the magnetic transformation point of the wire rod 60, which is based on the fact that the surface defects have a greater effect of quenching than the high-quality rolled wire surface and the recuperation rate is less than that of the high-quality rolled material surface in the recuperation process. In other words, while the wire is cooled to about 700 ° C. and then transported by a predetermined distance, the wire undergoes a recuperative process by its internal heat, and the surface temperature gradually increases. At this time, even if the temperature of the top portion of the surface rises above the magnetic transformation point of the wire rod (approximately 770 ° C), the defect portion of the surface stays below the magnetic transformation point of the wire rod because the effect of quenching is large compared to the top portion. Therefore, the present invention is based on performing eddy current flaw detection by using the temperature difference between the top and the defective part of the surface in the process of quenching the surface part of the wire rod and then reheating it. Here, the process of detecting the surface defect by using the defect signal according to the eddy current change of the defect portion in the signal processing means 210 according to the present invention is a well-known technique, and thus description thereof will be omitted.

As shown in FIG. 7, in one embodiment of the present invention, the distance L1 between the cooling means 100 and the temperature detecting means 50 is approximately 200 to 450 mm. In addition, the distance L2 between the temperature detecting means 50 and the signal detecting means 200 of the eddy current flaw detection is about 30 mm. The cooling means 100 is preferably supplied with high pressure water of approximately 11 kg / cm 2. Accordingly, the wire rod 60 has its surface portion cooled by the cooling means 100, and then transferred about 200 to 450 mm, and then the surface temperature is detected by the temperature detecting means 50, and then transferred about 30 mm. After that, the signal detecting means 200 detects the surface defect signal by performing surface defect eddy current inspection on the wire 60. The distance (L1, L2) is an example of the present invention can be set differently depending on the application of the site.

In this case, as shown in FIG. 8, when the cooling of the hot wire 60 above 900 ° C. is completed by the cooling means 100, the temperature of the hot wire 60 at this time is about 700 ° C. or less, and the rolled wire ( 60 is about 770 ° C. or more when the temperature of the rolled wire 60 is detected by the temperature detecting means 50 positioned 30 mm in front of the signal detecting means 200 of the eddy current flaw through the reheating process by the internal heat. In this case, the distance is preferably about 790 ° C. However, since the surface defect portion present on the surface of the rolled wire rod has a greater effect of quenching than the normal portion, the temperature of the defect portion is about 770 ° C. or lower, and thus has the magnetic transformation point region of the wire rod.                     

As described above, when the eddy current flaw detection is performed in the magnetic transformation point region of the hot wire 60 (approximately 770 ° C. or less), the magnetic permeability distortion of the eddy current is severe and the eddy current change is abrupt and the eddy current flaw is accompanied by a large noise. Based on this fact, the present invention has a hot hot wire surface temperature of at least about 770 ° C. (more preferably about 790 ° C.) or higher, and the temperature of the surface defect portion is determined by the magnetism of the wire. By providing eddy current flaw detection at a transformation point (about 770 ° C.) or less, it is possible to provide a hot wire on-line surface defect eddy current flaw detection apparatus and method with high reliability.

In a preferred embodiment of the present invention, the feed rate of the rolled wire 60 is preferably about 2.5 ~ 20m / s. In FIG. 7 and FIG. 8, since the cooling finish point A and the surface temperature detection point B are double-heated sections after cooling of the rolled material, the surface temperature of the rolled wire 60 detected at point B according to the feed rate of the rolled wire 60 is Have different values. Therefore, in one embodiment of the present invention, the distance L1 between the temperature detecting means 50 and the cooling means 100 may be changed according to the feed rate of the wire rod. Referring to FIG. 7, the feed speed of the wire rod 60 is measured by the speed detecting means 300, and the speed detecting means 300 is compared with the current speed through an internal processor (not shown), and the electric motor 150. It will control the forward and reverse operation of. As a result, the electric motor 150 is driven such that the surface temperature detected by the temperature detecting means 50 is equal to or higher than the magnetic transformation point temperature of the wire rod (about 770 ° C.), thereby providing a distance between the cooling means 100 and the temperature detecting means 50 ( L1) is adjusted. In addition, the distance L1 between the cooling means 100 and the temperature detecting means 50 may be changed according to the surface temperature detected by the temperature detecting means 50. That is, when the surface temperature detected by the temperature detecting means 50 is not greater than or significantly higher than the magnetic transformation point of the wire rod, the control means 51 controls the operation of the electric motor 150 so that the distance L1 is increased. Can be adjusted. For example, if the surface temperature detected by the temperature detecting means 50 is extremely high (about 810 ° C. or more), the distance L1 is adjusted to be smaller, and conversely, if the surface temperature is lower than the magnetic transformation point, the distance L1. Is adjusted to increase. As a result, the distance L1 can be adjusted such that the surface temperature detected by the temperature detecting means 50 is equal to or higher than the magnetic transformation point of the wire rod (about 770 ° C), preferably about 790 ° C or higher. Here, in one embodiment of the present invention is shown as adjusting the distance (L1) by adjusting the position of the cooling means 100 using the electric motor 150 coupled to the cooling means 100, In another embodiment of the invention, it is of course also possible to adjust the distance L1 by adjusting the position of the temperature detecting means 50. In FIG. 7, the cooling means 100 is moved as an example. As the means for moving the cooling means 100, when the electric motor 150 is driven, the screw driving gear 160 is interlocked with the screw 140. The movable base 120 is moved from the surface of the fixed base 110 by the rotation of) so that the cooling device 100 is variably moved to the front face of the flaw sensor 200.

9 to 20 show eddy current flaw detection results performed at each surface detection temperature region detected by the temperature detection means after quenching the hot wire of 900 ° C. or higher according to an embodiment of the present invention as described above. The drawings. Hereinafter, an embodiment of hot wire eddy current flaw detection will be described with reference to each drawing.                     

FIG. 9 illustrates the results of eddy current inspection of the rolled wire when the surface temperature of the hot wire is about 770 ° C. according to an embodiment of the present invention, wherein the surface of the rolled wire is free from defects. It is a state. Referring to FIG. 9, as a result of eddy current flaw detection under the eddy current flaw condition, 57 sintered levels, 43 flaw levels, and 38 confrontation levels exist without surface defects in the rolled wire. The flaw detection results were obtained respectively. Therefore, it can be seen that a large disturbance acts on the eddy current flaw detection due to the magnetic transformation point region of the rolled wire in the flaw detection temperature of the rolled wire.

FIG. 10 illustrates the results of conducting eddy current inspection of the rolled wire when the surface temperature of the hot wire is about 800 ° C. according to an embodiment of the present invention. It is a state. Referring to FIG. 10, as a result of eddy current flaw detection under the eddy current flaw detection condition, no sintering, blemishes, and confrontation levels were detected at all in the absence of surface defects in the rolled wire. Therefore, it can be seen that in the region where the flaw detection temperature of the rolled wire is about 800 ° C., there is no disturbance in the eddy current flaw detection of the hot wire.

FIG. 11 illustrates the results of eddy current inspection of the rolled wire when the surface temperature of the hot wire is about 1010 ° C. according to an embodiment of the present invention, wherein the surface of the rolled wire at this time is free from defects. It is a state. Referring to FIG. 11, as a result of performing eddy current flaw detection under the eddy current flaw detection condition, sintered, broken and confrontation flaw levels were not detected at all in the absence of surface defects in the rolled wire. Therefore, when the flaw detection temperature of the rolled wire is about 1010 ℃, it can be confirmed that no disturbance is applied to the eddy current flaw detection of the hot wire.

12 illustrates the results of eddy current flaw detection of the rolled wire when the surface temperature of the hot wire is about 1010 ° C. according to an embodiment of the present invention. to be. Referring to FIG. 12, as a result of performing eddy current flaw detection under the eddy current flaw condition, four sintered pieces, one heavy flaw, and one confrontation flaw exist in the presence of surface defects of the scaffold defect on the actual rolled material of the hot wire. It was detected in eddy current flaw detection. Therefore, it can be seen that in the region where the surface temperature of the rolled wire is about 1010 ° C., the eddy current flaw detection of the hot wire is performed without disturbing the eddy current flaw according to the size of the scap defect.

FIG. 13 shows the results of eddy current flaw detection of the rolled wire when the surface temperature of the hot wire is about 790 ° C. according to an embodiment of the present invention. It is a state. Referring to FIG. 13, as a result of performing eddy current flaw detection under the eddy current flaw detection condition, in the state of artificially causing a flaw defect on the surface of the actual hot wire, three sintered levels and four defect levels were found. A flaw detection result was obtained in which three defect levels were detected. Therefore, when the flaw detection temperature of the rolled material is about 790 ° C. above the magnetostriction region (770 ° C.) of the wire rod, and the surface temperature of the surface defect of the rolled wire rod is less than the magneto transformation region of the wire rod, the surface defect of the hot wire rod detects the eddy current flaw detection. In response to the means 200 (a flaw coil sensor) very sensitively, hot wire eddy current flaw detection results were obtained.

FIG. 14 shows the results of eddy current inspection of the rolled wire when the surface temperature of the hot wire is about 1010 ° C. according to an embodiment of the present invention, and part of the filament rolling section during the rolling process of the rolled wire at this time An uneven portion is artificially produced on the roll to cause an artificial roll-mark defect on the surface of the rolled material. Referring to FIG. 14, as a result of performing eddy current flaw detection under the eddy current flaw detection condition, in the state in which the surface defects of the roll-mark defect exist in the actual hot wire, one sintered piece, 0 serious defects, and one confrontation flaw are It was detected in eddy current flaw detection. Therefore, it can be seen that the eddy current flaw detection due to the mark defect is very low in the flaw detection temperature of the rolled wire is about 1010 ℃.

FIG. 15 shows the results of eddy current flaw detection of the rolled wire when the surface temperature of the hot wire is about 790 to 800 ° C. according to an embodiment of the present invention. An uneven portion is artificially produced on some of the rolls to cause an artificial roll-mark defect on the surface of the rolled material. Referring to FIG. 15, as a result of performing eddy current flaw detection under the eddy current flaw detection condition, in the state where surface defects of the roll-mark defect exist in the actual hot wire, one sintered flaw, two flaw flaws, and two confrontation flaws It was detected in eddy current flaw detection. Therefore, when the flaw detection temperature of the rolled wire is about 790 ° C above the magnetostriction area of the wire, and the surface temperature of the defect of the rolled wire mark is below the magnetotransform area of the wire (770 ° C), the surface defect of the hot wire is very good for the eddy current flaw sensor. When the reheating temperature of the hot wire detected by the temperature detecting means 50 at about 30 mm before the signal detecting means 200 (detection coil sensor) is detected by reacting sensitively and is about 790 ° C. Whereas the surface portion of the wire did not cause severe magnetic disturbances in the eddy current flaw above the magnetic transformation region (770 ° C.) of the wire rod, the mark defect was approximately 20 to about the high surface portion (about 770 ° C.) during recuperation after quenching. It can be seen that the magnetostriction point region (770 ° C.) or less of the wire rod, which has a temperature difference greater than 30 ° C., is obtained.

FIG. 16 illustrates the results of eddy current inspection of the rolled wire when the surface temperature of the hot wire is about 790 to 800 ° C. according to an embodiment of the present invention. Artificially scratched scratches in the previous step caused the artificial scratches on the surface of the rolled material. Referring to FIG. 16, as a result of performing eddy current flaw detection under the eddy current flaw detection condition, in the state where the surface defects of scratches are actually present on the hot wire, there are 19 sintered pieces, one heavy flaw, and one confrontation flaw in the eddy current flaw detection. Was detected in. Therefore, if the surface temperature of the rolled wire is about 790 ° C above the magnetostriction area of the wire rod, and the surface temperature of the rolled material scratched defect is below the magnetostriction area (770 ° C) of the wire rod, the surface defect of the hot wire is eddy current detection signal detection means. When the reheating temperature after the rapid cooling of the hot wire detected at about 30 mm from the signal detecting means 200 at about 790 ° C. is detected very sensitively to the 200 and the surface of the wire rod is of high quality. While the magnetic transformation region (770 ° C) or more does not cause serious magnetic disturbances in eddy current flaw detection, the scratched defects have a temperature difference of approximately 20-30 ° C or more than the high quality surface part (770 ° C) during the recuperation after quenching. It turns out that it becomes below transformation point area | region (770 degreeC).

FIG. 17 illustrates the results of eddy current flaw detection of the rolled wire when the surface temperature of the hot wire is about 790 to 800 ° C. according to an embodiment of the present invention. By changing the discharge amount of some of the rolls, artificially creating a fatal over-wrap defect during wire rod rolling, an artificial over-wrap defect is caused on the surface of the rolled material. Referring to FIG. 17, as a result of performing eddy current flaw detection under the eddy current flaw detection condition, in the state where surface defects of over-lap defects exist in the actual hot wire, 17 sintered pieces, 0 heavy defects, and 1 confrontation defect are It was detected in eddy current flaw detection. Therefore, if the surface temperature of the rolled wire is about 790 ℃ above the magnetostriction area of the wire rod, and the surface temperature of the rolled material over-lap defect is below the magnetotransform zone (770 ℃) of the wire rod, the surface defect of the hot wire is the eddy current flaw sensor. When the reheating temperature is about 790 ° C after the quenching of the hot wire detected at about 30 mm from the signal detecting means 200 (detection sensor) at a temperature of about 790 ° C, the hot wire is of high quality. Over-lap defects have a temperature difference greater than approximately 20-30 ° C compared to a good surface area (770 ° C) during recuperation after quenching, while the magnetostrictive region (770 ° C) does not cause severe magnetic disturbances in eddy current flaw detection. It can be seen that the magnetic transformation point region (770 ° C.) or less of the wire rod is made.

On the other hand, the temperature detection of defects for micro-defects of less than 1mm while moving at high speed is very difficult and impossible, so in order to find out which region the recuperation temperature of the recuperative process after quenching through the flaw sensor is approximately, The eddy current at 810 ° C, 830 ° C, and 850 ° C as shown in FIGS. 18 to 20 shows the recuperation temperature of the reheating process after the quenching of the hot rolled wire under the same conditions as the example of FIG. The results of each of the inspections are as follows.

First, FIG. 18 shows the results of conducting eddy current inspection of the rolled wire when the surface temperature of the hot wire is about 810 ° C. according to an embodiment of the present invention. In dogs, confrontation results were obtained in which two levels of confrontation were detected. Therefore, the results of the flaw detection were slightly different in the level of confrontation and sintering as compared with FIG. 12, but it can be seen that the surface detection temperature of the good part of the rolled wire is about 810 ° C. above the magnetostriction area of the wire. Although there is a slight difference depending on the size of the defect and the quenching condition, it can be seen that the surface defect of the hot wire was detected by the signal detecting means 200 (eddy current flaw sensor) in the magnetic transformation region (770 ° C.) or less of the wire. It can be seen that the eddy current flaw detection reliability of the hot wire is good.

19 shows the results of conducting eddy current inspection of the rolled wire when the surface temperature of the hot wire is about 830 ° C. according to an embodiment of the present invention. In dogs, confrontation results were obtained in which the level of confrontation was detected 1. Therefore, compared with FIGS. 12 and 18, the hot wire eddy current flaw detection results are slightly different at the level of confrontation and failure, and the surface flaw detection temperature of the rolled wire rod is about 830 ° C. above the magnetostriction region of the wire rod, and the surface of the rolled wire rod It can be seen that the surface defects of the hot wire were detected from the signal detecting means 200 (eddy current flaw sensor) at or below the magnetic transformation region (770 ° C.) of the wire rod depending on the size of the defect and the quenching condition. In addition, it can be seen that the reliability of the eddy current detection of the hot wire is slightly decreased.

Furthermore, FIG. 20 illustrates eddy current flaw detection of the rolled wire when the surface temperature of the hot wire is about 850 ° C. according to an embodiment of the present invention. In dogs, confrontation results were obtained in which the level of confrontation was detected 1. Therefore, compared with FIGS. 12 and 19, the hot wire eddy current flaw detection results are slightly different at the level of confrontation and failure, and the detection temperature of the good quality surface of the rolled wire is about 850 ° C. above the magnetostriction area of the wire, and the surface of the rolled wire The surface defect of the hot wire is detected from the signal detecting means 200 (eddy current flaw sensor) as shown in FIG. 12 in the temperature of the defect according to the size of the defect and the quenching condition. It can be seen that the eddy current detection reliability of the hot wire is somewhat reduced.                     

As described above, referring to the examples of FIGS. 18 to 20, in the eddy current flaw detection of hot wire, the eddy current flaw detection is performed in a section where the recuperation temperature is about 790 to 800 ° C. during the rapid cooling and reheating of the rolled material surface of 900 ° C. or more. It can be seen that the surface defect detection reliability is excellent.

The above description and the contents of the drawings are limited to one embodiment of the present invention, and thus the present invention is not limited thereto. It will be possible to substitute, change or delete the component according to the present invention within the scope of the technical idea of the present invention.

Accordingly, the scope of the present invention should be determined by the appended claims rather than by the foregoing description and drawings.

According to the present invention, since the surface defect state of the wire rod product can be confirmed in real time immediately after the wire rod rolling, quality control of the wire rod rolling work is performed in real time, thereby preventing the occurrence of a large amount of quality defects during the wire rod rolling operation.

In addition, the wire rod surface defects such as continuous scratches or continuous overlaps, which are impossible to detect surface defects, can be accurately detected by the vortex flaw inspection method, which is a conventional wire defect surface defect system.

Furthermore, the reliability of periodic defects and capacitive defect detection due to roll-mark defects generated during hot wire rolling is very excellent.

Claims (9)

Cooling means (100) for cooling the surface portion of the hot wire 60 during transfer; Temperature detecting means (50) spaced apart from the cooling means (100) by a predetermined distance (L1) in the conveying direction of the wire rod to detect the surface temperature of the wire rod (60); Control means (51) for outputting an eddy current flaw detection start signal when the surface temperature (T1) detected by the temperature detection means (50) is higher than the magnetic transformation point (T2) of the wire rod; When the eddy current inspection start signal is received from the cooling means 100 in the conveying direction of the wire rod by a predetermined distance (L2), an eddy current is generated on the surface of the wire rod 60 and the magnetic Signal detecting means (200) for detecting a surface defect signal by detecting a change in eddy current due to a surface defect at a temperature below the transformation point (T2); And Signal processing means (210) for analyzing the detected surface defect signal to determine the surface defect of the hot wire; Hot wire surface defect on-line eddy current flaw detection apparatus comprising a. The method of claim 1, Installed on the left and right sides of the signal detection means 200, respectively, the inlet and outlet flawless sleeve guides 410 and 420 for guiding the hot wire being transferred and attenuating the vibration of the signal detection means 200 are further provided. Including, The temperature detection hole 411 is drilled on the upper part of the inlet flaw sleeve guide 410, so that the signal detection means 200 measures the surface temperature of the guide wire through the temperature detection hole 411. Eddy current flaw detector for hot wire surface defects. The method of claim 1, Speed detecting means (300) for detecting a feed speed of the wire rod (60); And Drive means 150 for moving a predetermined member fixed to the cooling means 100 according to the detected speed; Hot wire surface defect on-line eddy current flaw detection apparatus further comprises a. The method of claim 3, wherein the driving means 150, Hot wire surface defect on-line eddy current flaw detection device, characterized in that it operates in response to the surface temperature (T1) detected by the temperature detection means (50). The method of claim 1, The cooling means 100 cools the hot wire 60 of 900 ° C or more and when the surface temperature of the wire detected by the temperature detection means 50 is 790 ~ 800 ° C, the wire detection in the signal detection means 200 Hot wire surface defect on-line eddy current flaw detection device, characterized in that for detecting the surface defect signal by generating an eddy current on the surface of the surface and detecting the change of the eddy current caused by the surface defect below 770 ℃. A cooling step of cooling the surface portion of the hot wire 60 being transferred; A temperature detection step of detecting a surface temperature of the wire rod 60 at a position spaced apart by a predetermined distance L1 from the point where the cooling is completed; A detection start signal outputting step of determining whether the detected surface temperature (T1) is higher than the magnetic transformation point (T2) of the wire rod and outputting an eddy current test start signal when the T1 is higher than T2; When the eddy current flaw detection start signal is received, an eddy current is generated on the surface of the wire rod 60 at a position separated by a predetermined distance (L2) from the point where the cooling is completed, and the surface defect at a temperature below the magnetic transformation point (T2). A signal detecting step of detecting a surface defect signal by detecting a change in eddy current caused; And A signal processing step of determining the surface defect of the hot wire by analyzing the detected surface defect signal; Hot wire surface defects online eddy current flaw detection method comprising a. The method of claim 6, Measuring a feed rate of the wire rod (60); And Changing the distances L1 and L2 according to the measured feed rate; Hot wire surface defect on-line eddy current inspection method, characterized in that it further comprises. The method of claim 6, Hot wire surface defect online eddy current inspection method further comprising the step of changing the distance (L1, L2) in accordance with the surface temperature (T1) of the wire rod detected in the temperature detection step. The method of claim 6, The cooling step cools the hot wire 60 above 900 ° C. and generates an eddy current on the surface of the wire in the signal detection step when the surface temperature of the wire detected in the temperature detection step 50 is 790˜800 ° C. And detecting a surface defect signal by detecting a change in eddy current caused by a surface defect of 770 ° C. or less.

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