KR101429982B1 - Scarfing apparatus and method for treating surface of slab using the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scarfing apparatus for removing surface coupling and / or scale of a slab by using high frequency induction heating, and a surface treatment method of a slab using the same.

The scarfing apparatus according to an embodiment of the present invention includes a high frequency induction heating unit configured to surround a circumferential surface of a slab to be transported and disposed in a certain region of the conveying apparatus and to melt the surface of the slab to be transported, A high-pressure fluid injecting portion disposed downstream of the induction heating portion in the conveyance direction of the slab of the conveying device and supplying any one of high-pressure oxygen, nitrogen, and helium to a region melted by the high- Pressure induction heating unit to the high-frequency induction heating unit so as to remove the non-product of the slab area before the high-frequency induction heating unit is introduced into the high-frequency induction heating unit, And a non-product removing unit.

According to the above-described structure, it is possible to eliminate the surface coupling of the slab so as not to generate the scarping mark through the scarfing device having a single structure, without using any additional finishing step, The entire surface treatment can be uniformly performed on the target area and the degree of melting (depth and / or speed) of the surface of the slab can be controlled according to the thickness of the slab and / or the defective state of the surface.

Slab, surface bonding, scale, scarfing device, high frequency induction heating

Description

[0001] SCARFING APPARATUS AND METHOD FOR TREATING SURFACE OF SLAB USING THE SAME [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scarfing apparatus for removing surface coupling and / or scale of a slab by using high frequency induction heating, and a surface treatment method of a slab using the same.

Generally, the surface of a slab cast in a continuous casting facility is affected by an oscillation mark caused by a mold oscillator, a surface crack due to a bending portion constituting a continuous casting facility, a non-metallic inclusion such as a mold powder, And / or internal inclusions such as gas. Since such slab surface defects are not removed through the rolling process, various surface defects 11 such as surface irregularities and / or stripe flaws are present on the surface of the slab 10 after hot rolling and / or cold rolling.

In order to remove the defects existing on the surface of the slab, defects existing on the surface of the slab are removed by various methods in the past. An example of removing the defects present on the surface of the slab is to transfer the rolled slab to the yard and then to remove the surface defects by cutting off the surface of the slab where defects exist using LNG gas and oxygen have. As another example, a method has been proposed in which a surface of a slab on which a bond is present is dissolved in an electric arc under vacuum to remove the surface modification and defects. As another example, a plasma torch and a rotating arm are provided in front of a slab cutting apparatus of a continuous casting facility to remove surface defects of the slab.

However, in most conventional techniques, nozzles arranged in a line are used to heat the surface of the slab with combustion heat, such as LPG or LNG gas or plasma, in order to remove surface defects of the slab, And a pair of nozzles. This structure allows the surface of the slab to be melted well at the center of the flame, but the surface of the slab is less melted at the edge region of the flame than the central portion. Therefore, as shown in FIG. 1, There is a problem that a scarfing mark 17 occurs.

On the other hand, in the case of using a flame, there is a problem that the untreated region 12 is present since surface defects are removed from a region of about 10 to 15 cm away from the end of the slab 10 due to the back flow of the flame.

In order to solve such a problem, conventionally, a slab subjected to a primary surface treatment while passing through a scarifying apparatus is subjected to a secondary surface treatment while passing through a separate grinding apparatus. In this way, the slab from which defects existing on the surface have been removed must be visually inspected by a human and the remaining surface defects must be removed again with a hand scarfing device.

Therefore, the conventional scarfing apparatus for removing defects existing on the surface of the slabs as described above requires a variety of auxiliary facilities such as a grinding facility, a hand scarping work site, a slab rotating facility, etc., , And the burden on the space and the cost was also increased.

The present invention has been made by recognizing at least any one of the problems or the problems that arise with respect to the conventional scarring apparatus and the surface treatment method of the slab.

An object of the present invention is to make it possible to remove surface defects of a slab by means of a scarifying device having a single structure.

Another object of the present invention is to make it possible to prevent the occurrence of a scarping mark by a scarping device

Another object of the present invention is to make the surface treatment for the target area for removing the surface defects of the slab to be uniform in the entire area.

Another object of the present invention is to minimize the inconvenience of removing slab surface defects.

Another object of the present invention is to provide an effect that an inclusion on the surface of a slab is floated by an electrostatic force in a direction perpendicular to a slab generated by a negative electromagnetic field of high frequency induction, .

Another object of the present invention is to make it possible to control the degree of melting of the slab surface depending on the thickness of the slab and / or the defective state of the surface

Another object of the present invention is to make it possible to control the degree of surface melting of the slab to an even region.

A scarping device related to an embodiment for realizing at least one of the above problems may include the following features.

The present invention is based on the premise that the surface defective region of the molten slab is basically removed by a high-pressure fluid through high-frequency induction heating.

A scarfing device according to an embodiment of the present invention includes a high frequency induction heating unit configured to surround a circumferential surface of a slab to be disposed and disposed in a certain region of a conveying apparatus and to melt the surface of the slab to be conveyed, A high-pressure fluid injecting portion disposed downstream of the induction heating portion in the conveyance direction of the slab of the conveying device and supplying any one of high-pressure oxygen, nitrogen, and helium to a region melted by the high- Pressure induction heating unit to the high-frequency induction heating unit so as to remove the non-product of the slab area before the high-frequency induction heating unit is introduced into the high-frequency induction heating unit, And a non-product removing unit.

In this case, the high-pressure fluid injection portion may be constituted by a single nozzle.

A method for surface treatment of a slab using a scarfing apparatus according to an embodiment of the present invention includes a transfer step of transferring a slab to a transfer device, a step of heating and melting the surface of the slab to be transferred to the high frequency induction heating part, And a step of removing surface defects in the region of the slab where the surface is melted by the high-pressure fluid spraying portion and removing the surface defects, and discharging the non-product scattered to the region of the slab before flowing into the high- Or by a vacuum suction device.

Preferably, the non-product removal step may be performed by supplying high pressure water or by vacuum suction.

More preferably, the melting depth of the slab by the high frequency induction heating unit can be controlled by adjusting the frequency.

Also, preferably, the melting speed of the slab by the high frequency induction heating unit may be controlled by adjusting the amount of electric power.
More preferably, the melting depth of the slab by the high frequency induction heating unit can be controlled by adjusting the amount of current according to the thickness of the slab.
More preferably, the melting depth of the slab by the high frequency induction heating unit can be adjusted by adjusting the frequency and the amount of current according to the thickness of the surface defect of the slab.

As described above, according to the present invention, the surface defects of the slab can be removed by the scarfing device having a single structure without requiring an additional finishing process.

Further, according to the present invention, a scarping mark is not generated by the scarping device.

Furthermore, according to the present invention, the surface treatment for the target area for removing the surface defects of the slab can be made uniform with respect to the entire area.

In addition, according to the present invention, it is possible to minimize the number of auxiliary facilities such as a fire fighting facility for installing a scarifying device for removing surface defects of a slab.

According to the present invention, the inclusions on the surface of the slab are floated by the electrostatic force in the direction perpendicular to the slab generated by the negative electromagnetic field of the high frequency induction, so that the surface coupling can be easily removed To do.

Further, according to the present invention, it is possible to control the degree of melting (depth and / or speed) of the surface of the slab in accordance with the thickness of the slab and / or the state of defects on the surface.

Further, according to the present invention, the degree of surface melting of the slab can be controlled in a uniform state with respect to the whole of the object region for removing the surface coupling of the slab.

In order to facilitate understanding of the features of the present invention as described above, a scarfing apparatus and a surface treatment method of a slab using the scarf according to an embodiment of the present invention will be described in detail below.

Hereinafter, exemplary embodiments will be described based on embodiments best suited for understanding the technical characteristics of the present invention, and the technical features of the present invention are not limited by the illustrated embodiments, It is to be understood that the present invention may be implemented as illustrated embodiments. Therefore, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. In order to facilitate understanding of the embodiments to be described below, in the reference numerals shown in the accompanying drawings, among the constituent elements which perform the same function in each embodiment, the related constituent elements are indicated by the same or an extension line number.

Embodiments related to the present invention are based on the principle that the surface defective area of the melted slab is removed by high-pressure oxygen through high-frequency induction heating.

As shown in FIGS. 2A and 2B, the slab 10 cut to a predetermined length by the rolling process will be described as an example of a more specific configuration of the scarifying device 100 according to an embodiment of the present invention. The scarifying device 100 may be provided in one area of the transfer device 20 to which the transfer device 20 is transferred. That is, in order that the surface defects of the slab 10 can be removed (modified) in the course of the slab 10 being conveyed by the conveying device 20 having a configuration such as a roller or the like, The scarifying device 100 may be disposed at a position so that the slab 10 can be continuously transported by the transfer device 20 after the surface defect has been removed through the scarifying device 100. [

The scarfing apparatus 100 is basically constructed so as to be heated by high frequency induction. The high-frequency induction can be configured to supply high-pressure oxygen to the region where the slab 10 is heated and melted to uniformize the melted region and / or remove (modify) surface defects. Accordingly, the conveying device 20 is provided with a separated area in the middle, and the scarifying device 100 can be disposed in the separated area of the conveying device 20. [ The slab 10 conveyed by the conveying device 20 may be removed (modified) while passing through the scarifying device 100.

The scarf device 100 may include a high-frequency induction heating unit 110 and a high-pressure fluid spraying unit 120. In this case, the high frequency induction heating unit 110 may be configured so that a coil through which a current flows is wound to generate an induction current. Such a configuration may be constituted merely by a coil alone, or may be constituted such that a coil is wound on a support by using a support capable of winding the coil. The slabs 10 pass through the center of the coils constituting the high frequency induction heating unit 110. In this case, the slabs 10 are arranged so that a uniform current density can be provided to each surface of the slabs 10 .

A high-pressure fluid injection part 120 may be disposed at one side of the high-frequency induction heating part 110. The high-pressure fluid injecting section 120 injects a high-pressure fluid to the heated region (melted region) of the slab 10 by the high-frequency induction heating section 110 to form a high- The defect is removed (reformed).

In this case, the high frequency induction heating unit 110 heats the slab 10 until the heating region of the slab 10 is in a molten state. In this state, due to the high-pressure fluid injected by the high-pressure fluid spraying unit 120 The surface defects can be removed with the region 10a of the melted slabs 10 being homogeneous (uniform). In this case, the high-pressure fluid injecting unit 120 may be configured to have a single nozzle so that the injected fluid can be injected at a uniform pressure with respect to the entire injection area of the slab 10.

Meanwhile, the fluid injected by the high-pressure fluid injecting unit 120 may remove surface defects of the slab 10 by using a gas such as oxygen, nitrogen, helium, or the like. The fluid sprayed by the high-pressure fluid spraying unit 120 can maintain or raise the temperature of the region 10a of the slab 10 heated by the high-frequency induction heating unit 110, The fluid that can be injected at a certain pressure is not limited to the above-mentioned fluid.

The area 10a of the slab 10 heated by the high frequency induction heating unit 110 is heated by the high pressure fluid injecting unit 120 to remove oxygen from the surface of the slab 10, So that oxidation heat is additionally generated by oxygen injected by the high-pressure fluid injecting section 120 so that the heating region 10a of the slab 10 is heated to a melting temperature You may. In this case, the slab 10 contains carbon, and when the slab 10 is heated, oxygen is supplied to the carbon contained in the slab 10, thereby causing an oxidation reaction. Due to this reaction, the temperature of the heating zone 10a of the slab 10 is further raised by the oxidation reaction, so that the heating zone 10a rises to a temperature higher than the melting point and surface defects can be removed.

A ratio of a ratio of a ratio of a ratio of a ratio of a ratio of a ratio of a ratio of a ratio of a ratio The non-material removing unit 130 may be further provided to prevent the product from dropping.

In other words, when high-pressure oxygen is injected into the heating zone 10a of the slab 10 to cause an oxidation reaction, the non-product may occur when high-pressure oxygen is injected from the high-pressure fluid injecting unit 120. In other words, Scattering occurs in the direction in which the slab 10 flows into the high frequency induction heating section 110 by the pressure of the fluid (that is, the pressure of the high-pressure oxygen). When the slab 10 is heated by the high-frequency induction heating unit 110, the heating state of the heated region 10a is made non-uniform. It can act as a possible factor.

Therefore, when the non-product is generated as described above, the non-product removing unit 130 may be provided to prevent the non-product from falling on the surface of the slab 10, as shown in FIG. have. The non-product removing unit 130 may be constructed using, for example, a high-pressure water injector capable of injecting high-pressure water or a vacuum suction apparatus operating in a high vacuum state.

In this case, the high-pressure water injector may be configured to have a single nozzle with respect to the entire region of the injection region so that the high-pressure water injected may uniformly be sprayed onto the surface of the slab 10. The vacuum suction apparatus may also be configured to be composed of a single nozzle with respect to the entire area of the suction area so that a uniform suction force can be provided to the surface area of the slab 10 in which the suction action takes place.

The scarfing apparatus 100 configured as described above may further include pinch rollers 140a and 140b at positions where the slabs 10 are introduced and / or discharged. The pinch rollers 140a and 140b are used to adjust the time during which the slabs 10 are held for heating when the slabs 10 are heated by the high frequency heating unit 110. In other words, 10 may be adjustable.

The heating of the slab 10 by the high frequency induction heating unit 110 is performed by an electromagnetic induction action as shown in FIG. 4, and a conductor such as a metal located in a coil through which an alternating current (high frequency) The principle is that the heat is generated by the resistance of loss and hysteresis loss (in the case of magnetic body).

When an alternating current (high frequency) current is passed through the coil, an alternating magnetic flux due to the alternating current around the coil is generated, and an induced current is generated in the conductor placed in this continuing state. This current is referred to as an eddy current (an electric force that prevents a change in the magnetic line of force generated in the conductor), and a joule heat is generated due to the resistivity of the heating target and the eddy current. It becomes a heat source. In such a high-frequency induction heating system, a magnetic body such as a slab has electrical loss due to magnetization, which is called hysteresis loss in addition to eddy current loss, so that heating is easier and heating efficiency can be maximized compared with non-ferrous metals.

The eddy current thus generated flows along the surface of the conductor. In the case of a cross section perpendicular to the current of the conductor, the amount of passing through the unit area of the cross section as shown in Fig. 4, that is, the current density is the same The current density decreases and the current density decreases from the surface to the center, that is, the skin effect (skin effect) occurs. This skin effect is related to the frequency, and the higher the frequency, the greater the skin effect.

Therefore, by controlling the thickness of the slab, the thickness of the surface defect of the slab, the frequency and / or the amount of current, it is possible to control the melting depth or the melting rate of the slab by using such effects. In this way, the surface of the slab 10 can be uniformly melted and the surface defect of the slab 10 can be removed, thereby making it possible to form a homogeneous slab surface.

5 is a graph showing a melted state with respect to the thickness of the slab according to the current density, the amount of power, and the cumulative heat amount. When the frequency is high, penetration depth (i.e., melting depth) is small and the amount of electric power It can be seen that the melting rate is large and the amount of electric power increases as the thickness of the material (slab) is thicker. That is, it is possible to control the melting process to be performed in a state suitable for the surface defects of the slab 10 based on the data values.

Meanwhile, the process in which the slab 10 transferred by the post-rolling conveying device 20 passes through the scarifying device 100 and surface defects are removed may be a continuous process.

The scarfing apparatus according to the embodiment of the present invention and the method of treating the surface of the slab using the scarf can be applied not only to the embodiments described above but also to various embodiments of the present invention, All or some of them may be selectively combined.

1 is a view showing the state of a slab surface-treated by a conventional scarifying apparatus.

2A is a perspective view schematically showing an example of a configuration of a scarifying device according to an embodiment of the present invention.

FIG. 2B is a perspective view schematically showing an example of the internal structure of the scarifying device shown in FIG. 2A.

3 is a view for explaining a concept of a state in which a surface of a slab is processed by a scarifying apparatus according to an embodiment of the present invention.

4 is a view for explaining the principle of melting the surface of a slab by a scarifying device according to an embodiment of the present invention.

5 is a graph showing the relationship between the thickness of the slab, the current density, the amount of cut, and the cumulative heat amount when the surface is melted by the scarifying device according to an embodiment of the present invention.

Description of the Related Art [0002]

10 ... Slab 20 ... Feeding device

100 ... scarping device 110 ... high frequency induction heating part

120 ... High-pressure fluid jetting part 130 ... Non-product removal

Claims (13)

A high frequency induction heating unit configured to surround the circumferential surface of the slab being disposed in one region of the conveying apparatus and melting the surface of the conveyed slab; A high-pressure fluid spraying part for spraying a high-pressure fluid to the high-frequency induction heating part, the high-frequency fluid spraying part being disposed downstream of the high-frequency induction heating part in the conveyance direction of the slab of the conveying device, ; And Pressure inducing heating unit to the high-frequency induction heating unit, the high-frequency induction heating unit being disposed before the high-pressure fluid ejecting unit in the slab feeding direction of the conveying device, A non-product remover provided as an apparatus; Wherein the scarifying device comprises: delete delete delete The scarfing apparatus according to claim 1, wherein the high-pressure fluid jetting portion is composed of a single nozzle. delete A conveying step of conveying the slab to the conveying device; Heating and heating the surface of the slab to be transferred to the high frequency induction heating unit; Removing surface defects in the area of the slab where the surface is melted by the high-pressure fluid spraying part; And Removing the non-product from the step of removing the surface defect to the area of the slab before being introduced into the high-frequency induction heating unit by the high-pressure water supply device or the vacuum suction device; And the surface of the slab. delete 8. The method of claim 7, wherein the non-product removal step is performed by supplying high pressure water or vacuum suction. 8. The method according to claim 7, wherein the melting depth of the slab by the high frequency induction heating unit is controlled by adjusting the frequency. 8. The method of claim 7, wherein the rate of melting of the slab by the high frequency induction heating unit is controlled by adjusting the amount of electric power. The method according to claim 7, wherein the melting depth of the slab by the high frequency induction heating unit is controlled by adjusting the amount of current according to the thickness of the slab. The method according to claim 7, wherein the melting depth of the slab by the high frequency induction heating part is controlled by adjusting the frequency and the amount of current according to the thickness of the surface defect of the slab.

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