KR101125937B1 - An on-line determination device of transformation ratio of steel plate using flux leakage - Google Patents

Abstract

The present invention relates to an apparatus for measuring the transformation amount of steel passing through the accelerated cooling stand online in the accelerated cooling stand after rolling.

The present invention is a device for measuring the transformation amount of the steel online while cooling the high temperature steel during transfer, the yoke is provided with both ends spaced apart from the steel while facing the steel material, the yoke is formed with a recess on the surface absence; First and second magnetic bodies provided at both ends of the yoke member, respectively; A magnetic flux detection sensor for detecting the strength of the leakage magnetic flux leaking from the recess among magnetic fluxes on the magnetic circuit formed of the first magnetic material, the steel material, the second magnetic material, and the yoke member; And an analysis unit for measuring a transformation amount of the steel according to the detected leakage magnetic flux intensity using a correlation between a preset leakage magnetic flux intensity and a transformation amount of steel.

According to the present invention, it is possible to secure the lift-off even in the vibration of the steel when measuring the transformation amount of the steel in the acceleration cooling stand, so that online measurement is possible, and the high temperature and high humidity inside the accelerated cooling stand is affected. There is an advantage that does not receive much.

Rolling, accelerated cooling stand, steel, transformation amount, magnetic material, leakage flux, yoke, recess

Description

Steel transformation amount on-line measuring device using leakage flux {AN ON-LINE DETERMINATION DEVICE OF TRANSFORMATION RATIO OF STEEL PLATE USING FLUX LEAKAGE}

1 is a schematic structural diagram of an interior of an accelerated cooling stand to which the present invention is applied.

2 is a magnetic characteristic change in accordance with the phase transformation in the cooling process of the cooling stage according to the present invention.

3 is a schematic configuration diagram of an apparatus for on-line deformation of steel materials using leakage magnetic flux according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: accelerated cooling stand 20: steel

111 housing 112 yoke member

113: recess 114: leakage flux detection sensor

115: first magnetic body 116: second magnetic body

117: analysis unit 118: magnetic flux

119: leakage flux 211: inlet pipe

212 discharge pipe 213 cooling material

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for on-line deformation of steel materials, and more particularly, to an apparatus for on-line measurement of the amount of transformation of steel passing through an inside of a high temperature accelerated cooling stand.

In general, when the hot-rolled steel is cooled by acceleration, particle refinement of the tissue is generated, thereby improving tensile strength, increasing toughness, and also allowing high input heat welding, thereby significantly reducing welding work.

In general, the high-temperature steel that enters the entrance of the accelerated cooling stand after rolling is cooled while being transferred through the inside of the accelerated cooling stand at a constant speed, and discharged into the low-temperature steel at the exit side of the accelerated cooling stand. Such steels are transformed from paramagnetic austenite to ferromagnetic ferrite by the cooling process in the accelerated cooling zone.

In order to achieve the desired ferromagnetic ferrite state at the side of the accelerated cooling stand, it is important to control the cooling process, especially the amount of cooling water. This is because excessive transformation occurs when the amount of cooling water in the accelerated cooling stand is large, and non-transformation occurs when the amount of cooling water is low. Therefore, the on-line measurement of the steel sheet during accelerated cooling after rolling is to control the amount of cooling water according to the amount of transformation of the steel, and it is important to secure the steel in a desired state at the exit of the accelerated cooling stand. In order to prevent plate deformation, it is essential to perform cooling control by measuring actual transformation rate in the accelerated cooling stand.

However, the accelerated cooling stand is a kind of black box, and it is difficult to easily measure the transformation rate of the steel plate therein, and in reality, it is very difficult to measure the temperature and transformation due to the extreme environment in the present accelerated cooling stand.

Conventional transformation measurement techniques include a temperature measurement method for measuring a temperature rise due to latent heat during phase transformation with a precision thermometer, a method using X-ray diffraction, a method using eddy current, and the like.

The temperature measurement method has a drawback that the information that can be obtained as an indirect method, rather than directly detecting phase transformation, is rough. In addition, there is a disadvantage in that responsiveness is difficult to secure precision and measurement using a radiation thermometer in a water-cooled environment is difficult.

The X-ray diffraction method can confirm only transformation information within 50 µm from the surface layer portion of the steel sheet. Therefore, the transformation properties of steel materials are inadequate in view of the fact that information needs to be taken out at a depth of 200 µm or more. In addition, in consideration of the poor cooling atmosphere of the mixed water and air in the accelerated cooling, it is fundamentally impossible to use, and there is a disadvantage that the apparatus used is an expensive large apparatus and difficult to maintain and repair. In addition, since strong X-rays are irradiated, there is a disadvantage in that radiation protection and shielding devices are necessary.

The eddy current measurement method can measure precisely in the laboratory environment but is very sensitive to the lift-off, the distance between the steel under test and the eddy current sensor.Therefore, there is a limit to obtaining a reliable signal in the field environment where various vibrations exist. have.

In addition, Republic of Korea Utility Model Application No. 1995-346, which is excited by different frequency bands and detects the magnetic flux shaped to output the organic electromotive force signal, by analyzing the signal filtered the organic electromotive force signal with a different frequency band filter Disclosed is a technique for measuring the amount of transformation, Korean Patent Application No. 1996-41353 discloses a technique for determining the fraction of each phase by using the x-ray paradigm analysis method, which is a method of analyzing the crystal structure, to obtain the rate of transformation, Korean patent Application No. 1996-51639 discloses a technique for obtaining permeability using a lift-off distance value and calculating the amount of transformation by the permeability. Korean Patent Application No. 1996-67984 discloses a maximum value of a measured voltage signal such as a unit time. The technique of measuring the metamorphosis rate by finding the bay is disclosed. In addition, Japanese Patent Laid-Open No. 5-126798 discloses an apparatus for forcibly magnetizing a steel plate and measuring the amount of transformation by measuring the magnetic change of the magnetized steel sheet. However, these techniques differ from the present invention in the principles, concepts and arrangements for measuring metamorphism.

Therefore, in the technical field, the necessity of a device for accurately measuring the amount of transformation of the steel passing through the interior of the accelerated cooling stand in order to accurately control the amount of cooling water in the accelerated cooling stand as a part for improving the quality of the steel. to be.

The present invention has been proposed to solve the above problems, after the steel rolling artificially leaked flux (flux) formed according to the magnetic properties of the steel passing through the accelerated cooling zone and the change of the leakage magnetic flux according to the magnetic change of the steel The purpose of the present invention is to provide a steel deformation amount on-line measuring device that can measure the transformation amount of steel online by detecting and analyzing it online.

In addition, another object of the present invention is to provide a steel transformation amount online measuring device excellent in applicability and simple structure to the environment of high temperature and poor accelerated cooling zone.

The steel deformation amount online measuring device using the leakage magnetic flux according to the present invention for achieving the above object, in the device for measuring the deformation amount of the steel online while cooling the high temperature steel during transport,

A yoke member having both ends spaced apart from the steel while facing the steel, and having a recess formed on a surface thereof; First and second magnetic bodies provided at both ends of the yoke member, respectively; A magnetic flux detection sensor for detecting the strength of the leakage magnetic flux leaking from the recess among magnetic fluxes on the magnetic circuit formed of the first magnetic material, the steel material, the second magnetic material, and the yoke member; And an analysis unit for measuring a transformation amount of the steel according to the detected leakage magnetic flux intensity using a correlation between a preset leakage magnetic flux intensity and a transformation amount of steel.

In one embodiment of the present invention, the measuring device may further include a housing having an internal space filled with a cooling material, wherein the yoke member, the first and second magnetic bodies, and the magnetic flux detection are provided in the internal space of the housing. The sensor is installed. In addition, the cooling material is one material selected from cooling oil, cooling water or cooling gas.

In addition, in one embodiment of the present invention, the magnetic material is a permanent magnet, preferably a samarium-based or naobib-based permanent magnet.

In addition, in one embodiment of the present invention, the leak magnetic flux detection sensor may include a Hall element, and the yoke member is preferably a U-shaped ferrite. At this time, the recess is formed inward from the surface of the yoke member, it is preferably formed to a depth of 10 to 20% of the width of the yoke member.

Further, in one embodiment of the present invention, while the steel is transferred at a constant speed, it is preferable to cool to a temperature of 500 ℃ to 600 ℃ at a temperature of 750 ℃ to 850 ℃, wherein the steel is 0.5 ~ 2.0 m It is preferable to feed at a speed of / s.

The present invention provides an apparatus for measuring on-line the amount of transformation of the steel passing through the acceleration cooling stand. The steel that passes through the accelerated cooling zone in the high temperature state is transformed from the paramagnetic austenite state to the ferromagnetic ferrite state through the cooling process. As described above, the magnetic change of the steel is generated through the acceleration cooling zone, and the intensity of the flux applied to the steel also changes according to the magnetic change of the steel. The present invention provides an apparatus for measuring the magnetic transformation amount of the steel passing through the acceleration cooling zone online by detecting and analyzing the change in magnetic flux intensity of the steel through the leakage magnetic flux.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying 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 structural diagram of a steel acceleration cooling stand to which the steel transformation amount online measuring apparatus of the present invention is applied. Referring to FIG. 1, first, the rolled steel 20 is introduced into the acceleration cooling stand 10 by the driving of the roller 11. As such, when the steel 20 is introduced into the acceleration cooling stand 10, the amount of the coolant 14 set by the cooling water nozzles 12 installed in the upper and lower parts of the acceleration cooling stand 10 is detected. Sprayed on the upper and lower surfaces of the steel 20 to cool the steel (20). In order to obtain a preferred transformation state of the steel according to the present invention, the temperature of the steel entering the accelerated cooling zone after rolling is preferably 750 ℃ to 850 ℃, the temperature of the steel discharged from the accelerated cooling zone is preferably 500 ℃. To 600 ° C., and the moving speed of the steel passing through the accelerated cooling zone is preferably 0.5 to 2.0 m / s.

Although not shown in the drawing, in the cooling device of the accelerated cooling table 10, high pressure compressed air is supplied through the air compressor and water is simultaneously supplied. The supplied compressed air and water meet each other at one point of the cooling water nozzle 12, and water is sprayed according to the outflow speed of the high pressure, thereby generating mists in which fine water particles are scattered by the high pressure compressed air. The mist generated as described above is sprayed at high speed on the surface of the steel 20 due to its ejection speed, thereby cooling the heat-treated steel 20 at high speed.                     

Through such a cooling process, since sufficient cooling is achieved in a short time, the structure of the heat-treated steel 20 is refined, and thus the tensile strength is sharply improved.

2 is a magnetic characteristic change in accordance with the phase transformation in the cooling process of the steel acceleration cooling stand according to the present invention. As described above, the steel 20 is rolled in the austenite state and then transferred to the accelerated cooling stand 10, cooled while passing through the accelerated cooling stand 10, and discharged in a ferrite state. Referring to FIG. 2, immediately after rolling, the temperature of the steel 20 is about 750 to 800 ° C. ((a) position), in this case, the austenite state (γ phase) of the face centered cube and the magnetic permeability μ is 1. When the steel 20 enters the accelerated cooling zone 10 and quenching starts, the temperature of the steel 20 gradually decreases and falls below the temperature of the A3 transformation line. The γ phase in the austenite state decreases gradually and the α phase in the ferrite state decreases. It will increase gradually. In this case, the ferrite phase is paramagnetic (α phase) since the Curie temperature is higher than or equal to 1. In other words, when the temperature is below the A3 transformation line, the phase changes little from the austenite state to the ferrite state. When the temperature is higher than the Curie temperature, all phases are paramagnetic, but when the temperature is lower than the Curie temperature, the ferrite phase becomes ferromagnetic. If the temperature of the steel 20 falls below the curie while the rapid cooling of the steel 20 proceeds, the ferrite phase transformed from the austenite state into the ferrite state has ferromagnetic properties and the permeability μ is greater than 1. It becomes around 70. The present invention intends to measure the amount of transformation of the steel using the principle that the magnetic property of the steel greatly changes (ie, the magnetic permeability μ ranges from 1 to 70) during the transformation process.                     

As the cooling process proceeds, the amount of transformation increases, which is a change from paramagnetic austenite to ferromagnetic ferrite. In addition, the lattice structure is changed from the face-centered cube to the body-centered cubic structure, so that a change in the metal phase occurs. Here, the transformation amount may be calculated using Equation 1 below.

[Equation 1]

Transformation rate (%) = {(α phase volume) / (total volume of metal)} × 100

3 is a schematic configuration diagram of a steel deformation amount online measuring device according to an embodiment of the present invention. Referring to FIG. 3, the steel deformation amount online measuring apparatus 100 using the leakage magnetic flux according to an exemplary embodiment of the present invention includes a housing 111 having an internal space containing a predetermined cooling material, and the housing 111. It is provided in the internal space of the yoke member 112, both ends of which are spaced apart from the steel 20 while facing the steel 20, the recess 113 is formed on the surface of the yoke member 112, Magnetic flux in a magnetic circuit formed through the first and second magnetic bodies 115 and 116, the first magnetic body 115, the steel 20, the second magnetic body 116, and the yoke member 112 respectively provided at both ends. The leakage magnetic flux detecting sensor 114 for detecting the leakage magnetic flux 119 leaking from the recess 113 among the 118, and analyzing the signal of the detected leakage magnetic flux to measure the amount of transformation of the steel 20. It is configured to include an analysis unit 170.

The steel transformation amount measuring apparatus 100 according to the present invention preferably measures the transformation amount of the steel 20 in close proximity to the high temperature steel 20, and therefore, an apparatus for cooling the measuring apparatus 100 is required. Can be. To this end, as shown in FIG. 3, in one embodiment of the present invention, an inlet pipe 211 and an inlet tube 211 for introducing the cooling material 213 from the outside are externally provided on one surface of the housing 111. It may include a discharge pipe 212 for discharging to. Accordingly, the cooling material 213 introduced from the outside through the inlet pipe 211 cools the yoke member 112, the magnetic bodies 115 and 116, and the leakage magnetic flux detection sensor 114 and then through the discharge pipe 212. It is discharged to the outside. Here, the cooling material 213 may be cooling water, cooling gas or cooling oil.

The magnetic bodies 115 and 116 may be preferably permanent permanent magnets, and more preferably, permanent magnets capable of retaining high energy and stably maintaining the function of the magnetic body at high temperatures. An example of the magnetic bodies 115 and 116 may be a samarium-based or naodium-based permanent magnet having a high Curie temperature and a high maximum energy. As a result, a magnetic flux path 120 is formed between the magnetic bodies 115 and 116 and the steel 20. In addition, as shown in FIG. 3, the magnetic bodies 115 and 116 are spaced apart from the steel 20 by a predetermined lift in the housing 111. This allows online measurement. As shown in FIG. 3, in one embodiment of the present invention, the magnetic bodies 115 and 116 are included in the housing 111. In another embodiment of the present invention, the magnetic bodies 115 and 116 are the housing 111. It may be arranged to protrude to the outside of the.

The leakage flux detection sensor 114 preferably includes a Hall element. The Hall device uses a voltage generated at a right angle in the direction of the magnetic field and the current in the solid state by the Hall Effect caused by the magnetic field and the current interaction, and the output is proportional to the product of the magnetic field and the current. Therefore, it can be used for magnetic field measurement, magnetic sensor, other ammeter, magnetic head, microwave power meter and so on. Those skilled in the art will be able to easily implement the sensor 114 for detecting the leakage flux using the Hall element.

As shown in FIG. 3, the yoke member 112 is preferably a ferrite having a substantially U shape in order to form a magnetic flux path well. However, although the yoke member 112 of the U shape is shown in FIG. 3 as a preferable embodiment, it is sufficient if it is a structure and a state in which a magnetic flux path is formed.

Meanwhile, referring to FIG. 3, a recess 113 having a predetermined size is formed on one surface of the yoke member 112. The recess 113 is formed to artificially leak the magnetic flux formed through the yoke member 112 to the outside. Therefore, the concave portion 113 may have any shape, and may have a shape and size (depth) such that the magnetic flux on the magnetic circuit formed through the yoke member 112 may be leaked. If the concave portion 113 is formed too small, the size of the leaked magnetic flux is small, thereby reducing the reliability of detecting the leaked magnetic flux. On the contrary, if the concave portion 113 is large, the work efficiency is reduced. Therefore, the recess 113 is formed inward from the surface of the yoke member 112, it is preferably formed to a depth of 10 to 20% of the width of the yoke member.

With reference to Figure 3, it will be described in more detail the steel deformation amount online measuring apparatus according to the present invention. As described above, the steel 20 entering the accelerated cooling zone 10 changes from a paramagnetic austenite state (γ phase) to a ferromagnetic ferrite state (α phase) as quenching proceeds. In a preferred embodiment of the present invention, in order to cool the high temperature steel during transportation and to measure the amount of transformation of the steel, the temperature of the steel entering the accelerated cooling zone 10 is 750 ° C to 850 ° C, and the accelerated cooling The temperature of the steel discharged from the base 10 is preferably 500 ℃ to 600 ℃, for this purpose it is preferable that the moving speed of the steel passing through the accelerated cooling zone is 0.5 ~ 2.0 m / s. In this case, as the steel 20 gradually changes to a ferromagnetic material, a magnetic circuit is formed between the first and second magnetic bodies 115 and 116, the steel 20, and the yoke member 112 installed at a predetermined interval from the steel 20. Is formed to generate the magnetic flux 118. The magnetic flux 118 gradually increases in strength as the steel 20 changes from paramagnetic austenite to ferromagnetic ferrite. This is due to the principle that the magnetic flux changes when the magnetic reluctance is changed in accordance with the transformation of steel on the magnetic circuit, in the same manner as the change of the resistance value on the electric circuit changes the current value.

On the other hand, as shown in Figure 3, on any surface of the yoke member 112, a recess 113 for artificially leaking the magnetic flux formed through the yoke member 112 is formed. Although the drawing shows that the concave portion 113 is formed at the top of the center of the yoke member 112, this is an example of the present invention and the concave portion 113 may be formed anywhere on the surface of the yoke member 112. have. In this case, a part of the magnetic flux 118 formed through the first and second magnetic bodies 115 and 116, the steel 20, and the yoke member 112 leaks in the recess 113 formed on the surface of the yoke member 112. . That is, the generated magnetic flux 118 flows along the inside and the surface of the yoke member 112. When the concave portion 113 is formed as shown in the figure, the magnetic flux is outward of the concave portion 113. Leaks. As described above, the leaked magnetic flux leaking from the recess 113 is detected by the leaked magnetic flux detection sensor 114.

As such, the steel 20 entering the accelerated cooling zone 10 is changed from a paramagnetic austenite state (γ phase) to a ferromagnetic ferrite state (α phase) as the quenching proceeds, and the steel 20 is As the ferromagnetic material gradually changes, the strength of the magnetic flux 118 on the magnetic circuit formed through the first magnetic body 115, the steel 20, the second magnetic body 116, and the yoke member 112 increases. Accordingly, the size of the leakage magnetic flux 119 leaking from the recess 113 is also increased. Therefore, the magnitude of the detection signal of the leakage magnetic flux 119 detected by the leakage magnetic flux detection sensor 114 increases as the transformation of the steel 20 proceeds.

As a result, the strength of the magnetic flux on the magnetic circuit formed through the first and second magnetic bodies 115 and 116, the steel 20 and the yoke member 112 increases according to the amount of transformation of the steel 20. As the intensity increases, the intensity of the leaked magnetic flux 119 detected by the leaked magnetic flux detection sensor 114 also increases. The analysis unit 117 detects the transformation amount of the steel 20 by analyzing the correlation between the leakage magnetic flux intensity and the transformation amount of the steel. Here, the analysis unit 117 may be implemented by a microprocessor or software, and those skilled in the art may implement the program by using a predetermined program. In addition, the analysis unit 117 may be able to receive the detection signal from the leakage flux detection sensor 114 wirelessly as well as through a wire. The apparatus for measuring the amount of transformation of steel online according to the present invention may be installed in a plurality of places in the accelerated cooling stand 10 to measure the amount of transformation of steel online at each position.

As described above, in the apparatus for measuring the amount of steel deformation according to the present invention, the amount of deformation of the steel 20 can be measured by detecting and analyzing the leakage magnetic flux in the recess 113 according to the amount of deformation of the steel 20. .

The description and the contents of the drawings described above describe the technical idea of the on-line deformation measuring apparatus for steel according to the present invention, which is illustrative of the best embodiments of the present invention and is not intended to limit the present invention. Particularly, although one embodiment of the present invention describes that a magnetic body can be applied as a permanent magnet, an electromagnet having a property of the magnetic body may be applied. Similarly, the concave portion may be a conventional scratch or scratch, etc., and may be formed of any structure as long as it can generate a leakage magnetic flux.

In addition, it is obvious that any person having ordinary skill in the art may make various modifications and imitations without departing from the scope of the technical idea of the present invention. Therefore, the scope of the present invention should be determined by the appended claims rather than by the foregoing description or drawings.

According to the present invention, since the lift-off can be sufficiently secured during the measurement of the transformation amount of the steel in the steel acceleration cooling stage, the steel can be measured online even if the steel vibrates.

In addition, there is an advantage that can accurately measure the amount of transformation online without being significantly affected by the harsh environment of high temperature, high humidity inside the accelerated cooling stand.

Claims (11)

In the device for measuring the transformation amount of the steel online while cooling the high temperature steel during transport, A yoke member having both ends spaced apart from the steel while facing the steel, and having a recess formed on a surface thereof; First and second magnetic bodies provided at both ends of the yoke member, respectively; A magnetic flux detection sensor for detecting the strength of the leakage magnetic flux leaking from the recess among magnetic fluxes on the magnetic circuit formed of the first magnetic material, the steel material, the second magnetic material, and the yoke member; And An analysis unit measuring a transformation amount of the steel according to the detected leakage magnetic flux intensity using a correlation between a preset leakage magnetic flux intensity and a transformation amount of steel; Steel transformation amount online measuring device comprising a. The method of claim 1, Further comprising a housing having an interior space filled with a cooling material, Steel deformation amount online measuring device, characterized in that the yoke member, the first and second magnetic bodies and the magnetic flux detection sensor is installed in the inner space of the housing. 3. The method of claim 2, The cooling material is steel deformation amount on-line measuring apparatus, characterized in that one of the material selected from the cooling oil, cooling water or cooling gas. 3. The method of claim 2, The housing is a steel deformation amount online measuring device, characterized in that it comprises an inlet pipe and the discharge pipe discharged to the outside the cooling material is introduced from the outside. The method of claim 1, The magnetic deformation amount online measuring device, characterized in that the magnetic material is a permanent magnet. The method of claim 5, The magnetic material is steel metamorphic on-line measuring device, characterized in that the samarium-based or Naobium-based permanent magnet. The method of claim 1, The magnetic flux detection sensor comprises a Hall element (Hall element) characterized in that the steel deformation amount online measuring device. The method of claim 1, The yoke member is a steel deformation amount online measuring device, characterized in that it comprises a substantially U-shaped ferrite. The method of claim 1, wherein the recessed portion, Steel deformation amount formed online from the surface of the yoke member, 10 to 20% of the width of the yoke member, characterized in that the on-line deformation apparatus. The method of claim 1, wherein the steel material, Steel transformation amount online measuring device, characterized in that cooled to a temperature of 500 ℃ to 600 ℃ at a temperature of 750 ℃ to 850 ℃ while being transferred at a constant speed. The method of claim 1, The steel sheet is online deformation measuring device characterized in that the conveyed at a speed of 0.5 ~ 2.0 m / s.

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