KR101353674B1 - Descaling apparatus for hot rolled steel strip using low temperature pre-treatment - Google Patents

Abstract

Provided is a descaling device provided to remove scales or other residual foreign matter produced on the surface of a hot rolled steel sheet.
The scale removal apparatus of this invention is a cooling tank provided on the conveyance path of a steel plate as a structural example, and the scale breaker provided downstream of the said cooling tank; And a slurry spray unit provided to remove the scale on the downstream side of the scale breaker.
According to the present invention, through the condensation of the steel sheet scale layer by the low temperature cooling pretreatment and the application of the tension through the breaker, the scale layer is induced to fall off and promotes the crack generation, at least in the (polishing) slurry spray portion It is possible to obtain an improved effect of increasing the scale removal efficiency, shortening the scale processing time of the steel sheet, and providing an environmentally friendly device compared to the conventional chemical pickling treatment.

Description

Descaling apparatus for hot rolled steel strip using low temperature pre-treatment

The present invention relates to a descaling device provided to remove scales or other foreign matter produced on the surface of a steel sheet, in particular hot rolled steel sheet, and more particularly through condensation and breaker of the steel sheet scale layer by (preheating) cold pretreatment. Through tension application, the scale layer is eliminated and cracks are promoted, thereby maximizing the scale removal efficiency at least in the (polishing) slurry spraying section, reducing the scale processing time of the steel sheet, and reducing the scale treatment time of the steel sheet. The present invention relates to a descaling device using cooling pretreatment that enables the construction of environment-friendly devices.

Scale layers of approximately several to several tens of micrometers are formed on the surface of steel sheets such as carbon steel hot rolled at high temperature, high strength steel, silicon-added steel for electric motors (electric steel sheet) or stainless steel hot rolled steel sheets (steel strip).

On the other hand, Figure 1 shows a facility for removing the scale generated on the surface of such a hot rolled steel sheet.

That is, as shown in FIG. 1, the pickling facility for removing a conventionally known scale generates a crack (cracks) on the scale of the steel sheet surface by using the scale breaker 10, and then pickling bath 40. ) And the scale was removed while passing through the washing tank (50) step by step.

The pickling bath 40 is composed of a plurality of unit pickling tanks, and the pickling tank chemically removes the scale of the surface of the hot rolled steel sheet through the high temperature strong acid such as hydrochloric acid or sulfuric acid. In this case, reference numeral 10 in FIG. 1 denotes a payoff reel, 20 denotes a welding machine, and 60 denotes a tension reel, and the water washing tank 50 is not specifically illustrated, but may be divided into a brush and a rinse cleaning step.

However, the existing descaling method based on pickling as shown in FIG. 1 increases the length of equipment according to the use of a plurality of pickling tanks and washing tanks, inhibits the working environment due to generation of acid vapors, causes environmental hazards due to waste acid treatment, and There have been various problems such as an increase in auxiliary facilities due to recovery and acid resistance facilities, a difference in scale removal ability according to steel grades, or a poor quality of the steel sheet stayed in the acid solution tank and the water washing tank when the line stops.

In addition, although schematically illustrated in FIG. 1, in the case of the existing pickling equipment, since the length of the pickling tank 40 and the washing tank 50 reaches approximately 100 M, when the line is stopped, the hot rolling is caught in the pickling tank and the washing tank. The steel sheet had poor surface quality due to excessive acid treatment. In addition, the installation space was considerable.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. 2002-275666 or 2002-371314, etc., in order to replace the descaling of pickling, a shot ball, grit, or the like of metal is used. There is also a method of removing the scale of the steel plate surface by colliding with the steel plate surface.

However, such a physical removal method is also mostly parallel with the pickling process as a pretreatment step of the pickling process for improving the pickling efficiency, and is particularly difficult to apply to a hard pickling steel grade such as a grain-oriented electrical steel sheet.

In addition, there is known a method for removing scale through injection of high pressure water as in Japanese Patent Laid-Open No. 2004-074178, and a method for spraying ice particles as in US Pat. No. 6,328,631. The descaling performance was insufficient or difficult to use.

In addition, related facilities or processing methods for continuously linking physical scale removal with a rolling process or a plating process have been proposed in Japanese Patent Laid-Open No. 2003-064461 or US Pat. No. 6,088,895.

For example, Japanese Unexamined Patent Publication No. 2003-064461 suggests a tension leveler or a short blasting method as an auxiliary means for pickling, and in the case of US Patent No. 6,088,895, the surface roughness is 0.3 μm or less. Stainless steel cold rolled steel for adjustment is the object. However, in the case of the actual stainless steel sheet, it is difficult to effectively perform descaling effectively only by the method proposed in the US patent.

For example, a surface removal scale of a steel sheet is first condensed through cooling at low temperature to maximize crack expansion in a scale breaker, and thus, a scale removal technique maximizing scale dropping (peelability) in the blasting stage of the polishing slurry has been proposed. There is no bar.

The present invention has been proposed in order to solve the conventional problems as described above, the object of the aspect is, through the condensation of the steel sheet scale layer by the low temperature cooling pretreatment and the tension applied through the breaker, induces the crack of the scale layer and cracks Scaling with cooling pre-treatment that accelerates generation, improves the scale removal efficiency at least in the (polishing) slurry spraying section, reduces the scale processing time of the steel sheet, and provides an environment-friendly device compared to the conventional chemical pickling treatment. It is to provide a removal device.

As a technical aspect for achieving the above object, the present invention, a cooling tank provided on the conveying path of the steel sheet; and a scale breaker provided on the downstream side of the cooling tank; And a slurry injection unit provided to remove the scale on the downstream side of the scale breaker.
The cooling tank has an inlet and an outlet provided with steel sheet conveying guide rolls through which the steel sheet passes, filled with a refrigerant for cooling the steel sheet, and a cooling tank chamber having heating means for temperature control, and the cooling tank chamber. It comprises a plurality of steel sheet feed roll provided to enable the refrigerant deposition transfer of the steel sheet,
The slurry spraying unit may include a housing disposed in a chamber corresponding to a traveling path of a steel plate, high pressure water spraying means provided in the housing, abrasive input means provided in the housing to one side of the high pressure water spraying means, and a lower portion of the housing. Slurry injection means provided to spray the polishing slurry in which the high pressure water and the abrasive is mixed on the steel sheet,
The slurry spraying means may include a spraying hole assembled in a lower portion of the housing, a depression formed by mixing high pressure water and an abrasive into the spraying hole, and a slurry spraying hole provided in a slit structure through the spraying hole from the depression. And mixing means provided with a grid or rods in a circular ring to induce mixing of the high pressure water injected into the housing and the introduced abrasive.

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At this time, the refrigerant is provided as a liquid containing water and alcohol, or an alcohol solution supplied with liquid nitrogen through the liquid nitrogen supply port provided in the cooling chamber chamber, but provided to maintain a temperature of -10 ℃ ~ -100 ℃ Will be.

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More preferably, the high pressure water injection means, the high pressure water supply port is assembled to the upper portion of the device housing is supplied with high pressure water;

A high pressure water nozzle assembled to the high pressure water supply port and provided to spray high pressure water in a housing;

As shown in FIG.

More preferably, the abrasive input means includes an abrasive input pipe connected to the housing, and the abrasive is configured to be sucked into the housing by a negative pressure space formed by high pressure water injection inside the housing.

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More preferably, the abrasive is formed of one of silicon oxide, silicon carbide, aluminum oxide, glass and ceramic having a specific gravity less than that of metal.

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In addition, the solution of the above-mentioned problems does not list all the features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The various features and advantages and effects of the present invention can be understood in more detail with reference to the following specific embodiments

According to the present invention, the hot rolled hot rolled steel sheet is condensed into the scale layer on the surface of the steel sheet through the scale pretreatment of low temperature cooling, and then a tension is applied to the steel sheet through the scale breaker to induce the scale to drop easily, thereby causing cracking. It is to make it possible to promote.

Therefore, the present invention maximizes the scale removal efficiency at least in the spray section of the slurry (polishing slurry), enables the reduction of the slurry spraying capability, and in particular, shortens the scale processing time of the steel sheet and increases productivity.

Above all, since the present invention does not go through the existing chemical pickling process that causes the environmental pollution, it is possible to construct and operate a more environmentally friendly facility, and the length of the facility is also reduced.

That is, the present invention enables shortening of equipment length, reduction of manufacturing cost, increase of scale removal efficiency, improvement of surface quality of hot rolled steel sheet, and the like.

1 is a schematic process diagram showing a descaling process through conventional chemical pickling
Figure 2 is a schematic diagram showing a descaling apparatus according to the present invention
3 is a block diagram showing a cooling tank according to the present invention
Fig. 4 is a front view of Fig. 3
5 and 6 is a schematic view showing a schematic view, an exploded view and a resupply supply system showing a slurry spray unit of the present invention.
Figure 7 is a schematic diagram showing a state of recycling the slurry slurry of the present invention slurry injection unit
8A and 8B are photographs showing experimental simulations and scale peeling surfaces when removing scales according to the present invention.
9A and 9B are graphs and tables showing peel strength of scales with temperature changes associated with the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings.

First, Figure 2 shows the overall configuration of the descaling device 100 according to the present invention, such a descaling device 100 of the present invention, hot rolled steel sheet, in particular, hot-rolled carbon steel, high strength steel, An apparatus for removing scales of hot rolled steel sheets (steel strips) such as silicon-added steel (electric steel sheet) or stainless steel for electric motors.

For example, as shown in FIG. 2, the scale removing device 100 of the present invention basically has a cooling tank 200 provided on a transport path of a steel plate, and a scale breaker provided downstream of the cooling tank 200. 300, and a slurry spray unit 400 provided to remove the scale on the downstream side of the scale breaker 300.

Therefore, as will be described in detail below, the scale removing apparatus 100 of the present invention, first, the scale of the steel sheet, the slurry, that is, a slurry in which water and abrasives are mixed (also referred to as' polishing slurry ') (' SC in FIG. 3). ') Before spraying and finally removing the scale layer on the surface of the steel sheet in advance to facilitate the dropping of the scale, and the scale cracking through the next scale breaker 300 or slurry spray unit 400 and It is to facilitate removal.

That is, as shown in Figures 2 to 4, the technical feature of the present invention, the low carbon steel, ultra-low carbon steel, high-strength carbon steel, high carbon steel, electrical steel sheet, stainless steel, such as hot rolled steel sheet (steel) cooling tank 200 To pass through.

At this time, since a difference occurs in the coefficient of thermal expansion between the steel sheet and the scale layer of the steel sheet surface layer, stress generation in the steel sheet and the scale interface layer is increased during the quenching treatment of the steel sheet.

For example, the scale layer formed on the surface of the steel sheet 102 is mostly composed of Fe ₃ O ₄ , such a thermal expansion coefficient of Fe ₃ O ₄ is 10.7 × 10 ^-6 / ℃, the thermal expansion coefficient of iron is 15.3 × 10 ^-6 / deg.

Therefore, when the steel sheet 102 on which the scale layer is formed is cooled at a low temperature, since the condensation of the steel sheet becomes larger than Fe ₃ O ₄ of the scale layer, stress is concentrated on the interface layer.

As a result, as shown in FIG. 2, when the hot rolled steel sheet passes through the cooling bath 100 of the apparatus of the present invention in a continuous process, the stress is increased at the interface between the scale SC and the hot rolled steel sheet 120, thereby improving the scale breaker ( When a tension by 300 is applied, the scale layer is more easily removed, and thus the removal efficiency of the scale of the high pressure, high speed sprayed steel sheet is maximized while passing through the chamber 402 of the slurry injection unit 400. do.

That is, the apparatus of the present invention increases the frequency of occurrence of internal cracks in the scale, thereby facilitating removal of the scale through spraying the steel sheet of the slurry mixed with the abrasive and water.

In particular, as described above, in the existing pickling equipment, as shown in Fig. 1, since several pickling tanks 40 and washing tanks 50 are constructed at about 100M, when the line is stopped, pickling Hot rolled steel sheets hanging in baths and wash tubs will have poor surface quality.

However, in the case of the present invention, according to the target production rate, at least 50% or more of the de-scale is induced through the pretreatment of the cooling through the cooling tank 200 and the scale breaker 300, and the abrasive of the second small particle size ( High pressure, high speed spraying the slurry (S) containing C) to the steel sheet to remove the scale layer.

Therefore, in the case of the present invention it is possible to further reduce the construction length of the scale removal equipment than using only the slurry injection unit 400, it is also possible to reduce the overall failure rate.

In particular, the present invention can be easily applied to special steels, such as general carbon steel, high strength steel, electrical steel sheet, and stainless steel, which are hardly pickled, unlike the existing strong acid pickling.

Next, FIGS. 2 to 4 illustrate the cooling tank 200 described above in the descaling apparatus 100 according to the present invention.

That is, as shown in Figures 3 and 4, the cooling tank 200 of the present invention, specifically, the cooling tank chamber 210 provided with the inlet, outlet 212, 214 through which the steel plate 102 passes. It includes.

In addition, the inlet and outlet 212 and 214 of the chamber 210 of the cooling tank 200 are provided with steel sheet feed guide rolls 232 for entering and exiting the chamber of the steel sheet, and at the same time the cooling chamber chamber ( Inside the 210, a plurality of feed rolls 230 for transferring the steel sheet 102 to a specific route are disposed.

For example, the transfer rolls 230 in the chamber determine the transfer path of the steel sheet, preferably to be immersed in the refrigerant 216 filled in the chamber 210 of the cooling tank 200 as much as possible. .

Therefore, the steel sheet is transported through the refrigerant 216 as much as possible, and expands the detachment of the scale and the promotion of cracking in the scale breaker through the low temperature cooling described above.

On the other hand, the refrigerant 216 to be filled in the chamber of the cooling tank 200 of the present invention is a liquid containing water and alcohol, or a liquid nitrogen supply port connected to the lower portion of the cooling tank chamber 210 in a predetermined pattern ( 218 may be provided as an alcohol solution to which liquid nitrogen is continuously supplied. Preferably, the temperature of the refrigerant 216 is maintained at -10 ° C to -100 ° C.

Therefore, although schematically illustrated in the drawing, the chamber 210 of the cooling tank 200 needs to be provided as a structure capable of withstanding the temperature.

On the other hand, as shown in Figure 4, the steel sheet feed roll 230 provided to the chamber 210 of the cooling tank is provided with a power applying roll that the shaft of the roll is penetrated in watertight state to the chamber in conjunction with the motor 231 of the steel sheet In view of the smooth transfer and adjustment of the feed path, it would be desirable.

That is, the steel sheet conveying roll 230 enables the bending conveying path of the steel sheet, which will facilitate low temperature cooling through the delay of the refrigerant passing time of the steel sheet.

Of course, although schematically shown in Figures 2 and 3, the steel sheet feed rolls 230, such as a looper roll, it will be possible to form the roofing of the steel sheet.

More preferably, the bottom of the cooling chamber chamber 210 is to provide a heating means 250 for controlling the temperature of the refrigerant in a suitable arrangement, for example, as shown in Figs. 3 and 4, the heating block 252 It may be provided in the form of embedding the heating wire 254 in the interior.

Therefore, as shown in FIG. 3, when the temperature sensor 274 is installed in the chamber and connected to the device control unit 270, the power supply unit 272 connected to the device control unit 270 is a hot wire 254 of the heating means 250. ), And the temperature of the refrigerant may be controlled through the supply and heating of the liquid nitrogen.

Then, the steel sheet 102 passing through the chamber of the cooling tank 200 is subjected to bending by the bending roll of the scale breaker while tension is applied from the scale breaker 300, and at this time, the steel sheet 102 is subjected to low temperature cooling to the scale layer of the steel sheet. The scale may be peeled off through the cracks formed, or the crack layer may be further expanded, and finally, descaling in the slurry injection unit will be assured.

At this time, as described above, the temperature range of the refrigerant is suitable -10 ℃ ~ -100 ℃, when the temperature of the refrigerant is -10 ℃ or more, the condensation effect by low temperature cooling is insufficient, conversely the temperature of the refrigerant- If the temperature is less than 100 ° C., the efficiency of the scale breaker due to the condensation of the scale increases, but the consumption of liquefied nitrogen for cooling increases, which may cause problems in terms of maintenance.

On the other hand, the scale breaker 300, although not shown separately in the drawings by reference numerals, tension bridle roll (tension bridle roll), anti-camber roll (anti-camber roll), which can impart tension and elongation, It consists of leveler roll, bending roll, etc., anti-camber roll and leveler roll straighten the shape of steel sheet.

At this time, as the elongation and bending amount increase, the effect of dropping and cracking of the scale layer increases, but excessive elongation may damage the steel sheet, so that the elongation of the scale breaker 300 is 0.5 to 3.0%, and the bending amount by the bending roll is 10. The range of ~ 50 mm is appropriate.

For example, when the elongation is 0.5% and the bending amount is 10 mm or less, the effect of descaling and scale cracking is insufficient, and when the elongation is 3% and the bending amount is 50 mm or more, the material becomes hard and the shape correction becomes excessive. Can be.

In addition, as the elongation and bending amount of the scale breaker increases, the dropout rate of the scale increases and the crack generation density increases, and as the crack density increases in the scale layer, it is easy to remove the scale through subsequent slurry spraying, and By optimizing the high pressure slurry spraying conditions such as abrasive size and spraying pressure, the surface roughness of the hot rolled steel sheet can be adjusted to an appropriate range.

Therefore, in the case of the present invention, before the scale breaker step, the scale is pretreated by low temperature cooling to maximize the removal efficiency through cracking and slurry blasting of the scale.

On the other hand, in Figures 8 and 9, the peel strength at the time of scale drop according to the temperature of the hot rolled steel sheet of the general low carbon steel is measured by using the bond joint strength (hereinafter referred to as 'Lap Shear experiment') experiment, the photograph and the temperature and peeling of the specimen Strength-related graphs and tables are shown.

8A and 8B are simulations of Lap Shear test. The Lap Shear test shows the tensile strength when the scale is peeled off through the tensile test after attaching the hot rolled steel sheet (plate) having the scale with a structural adhesive. How to measure.

In the following, the tensile strength at the time of peeling will be described below as 'scale peel strength'. That is, FIG. 8B is a photograph showing the scale layer peeled off after the Lap Shear experiment.

Meanwhile, in the experiment, the refrigerant 216 of the cooling tank 200 used a solution containing 50% water and 50% alcohol, and maintained a low temperature while continuously supplying liquid nitrogen in the air, and the immersion time of the specimen. 10 seconds, Lap Shear experiment was performed after confirming the proper temperature through a thermometer attached to the specimen.

Therefore, as shown in Fig. 9, the Lap Shear test result shows that the peeling strength at room temperature is 19.9MPa and the peeling strength is significantly decreased as the temperature of the hot-rolled steel sheet decreases to 9.5MPa at -80 ° C.

In conclusion, when the temperature of the hot-rolled steel sheet is reduced, it can be seen that the peeling of the scale becomes easy even when a small tension is applied by increasing the stress at the interface between the scale and the steel sheet.

Next, FIGS. 2 and 5 to 7 show the slurry spray unit 400 for finally removing the scale on the surface of the steel sheet in the scale removing apparatus 100 of the present invention.

That is, as shown in Figure 2, the slurry spray unit 400 of the present invention, a plurality of chambers 402 through which the steel sheet passes therein may be provided in a suitable arrangement on the upper, lower side of the steel sheet.

Of course, the unit slurry injection unit 400 is a high pressure injection of water in the housing 410 through the abrasive supply line (L2) and high pressure water supply line (L1), the abrasive (C) to form a negative pressure space Slurry (S) mixed with high-pressure water (water) and abrasive (C) having a bead (grain) structure of a predetermined particle size through the injection hole of the housing through the injection port of the housing as shown in FIG. The high pressure and high speed are sprayed on the surface of the steel sheet 102, so that the abrasive can effectively remove the scale layer, and in particular, the roughness management of the surface of the steel sheet.

Therefore, the slurry injection unit 400 of the scale removing apparatus of the present invention will be described in detail with reference to FIGS. 5 to 7.

Basically, the slurry injection unit 400 of the present invention, as shown in Figures 5 and 6, the housing 410 disposed corresponding to the traveling path of the steel sheet in the chamber 402 of the box-shape described above And, the high pressure water injection means 430 provided in the housing, the abrasive input means 450 provided in the housing to one side of the high pressure water injection means, and a polishing slurry in which the high pressure water and the abrasive is mixed in the lower portion of the housing ( S) may be configured to include a slurry spraying means 470 provided to spray the steel sheet.

Therefore, when the abrasive C and the high pressure water, that is, the high pressure water W are inclined to the upper side and one side of the housing, the negative pressure space T is formed in the space inside the housing according to the high pressure water injection. The supply of abrasive to the negative pressure space is smoothly performed without external power application, so that the mixing of water and abrasive in the mixing zone (MT) is very dense, resulting in a slurry in which water and abrasive are mixed in a very uniform distribution. (S) is evenly sprayed on the surface of the steel sheet 102 through the injection means 470, which is to increase the scalability.

The slurry spray unit 400 of the present invention does not need the existing pickling tank (40 in FIG. 1), which simplifies the size of the equipment, and enables sufficient removal of the scale even when the steel sheet 102 is advanced at high speed. And average surface roughness Ra of the steel plate after descaling are managed uniformly to 1-1.5 micrometers.

Therefore, the scale removal apparatus 1 of the present invention not only secures the scale removal efficiency but also makes the surface roughness of the steel sheet after the scale removal appropriate, so that subsequent processing such as processing characteristics, cold rolling and plating required by the demand for the steel sheet is required. It is possible to cope with various conditions of surface roughness required in the process.

On the other hand, such a slurry, that is, the abrasive included in the polishing slurry (S) (C in Fig. 5) to remove the scale layer by collision, preferably provided with an abrasive having a specific gravity smaller than the metal, for example Silicon oxide, silicon carbide, aluminum oxide, glass, ceramic, or the like may be provided. Preferably, glass or ceramic beads having a uniform particle size are used.

On the other hand, the glass or ceramic beads of such an abrasive preferably have a particle diameter of about 10 to 400 m. For example, when the diameter of the abrasive is 10 μm or less, it is so fine that the effect of removing the scale layer on the surface of the steel sheet is insignificant. On the contrary, when the particle size of the abrasive is 400 μm or more, the scale removal efficiency is increased and the roughness deviation of the surface of the steel sheet is increased. Generated and undesirable.

On the other hand, it is preferable that the high-pressure water injection pressure injected from the inside of the housing 410 is also adjusted uniformly. Assuming that the glass beads having a particle diameter of 10 to 400 μm as described above, the high-pressure water injection pressure is 100 to 500 The range of bars is adequate. For example, when the pressure of the high-pressure water W is 100 bar or less, the slurry spraying pressure is small and the scale removal efficiency is insufficient. On the contrary, when the pressure of the high pressure water W is 500 bar or more, the steel plate impact pressure of the abrasive is high, and the surface roughness Ra of the surface of the steel sheet varies. Will be generated.

On the other hand, as shown in Figure 5 and 6, the housing 410 of the slurry injection unit 400 of the present invention, the high-pressure water injection means 430, abrasive injection means 450 and slurry injection means 470 Each of the first to third housings 412, 414, 416, which are associated or assembled, wherein the second housing is formed to be inclined, and the first and third housings are provided in a straight line as a whole.

And, as shown in Figure 5, the nozzle 434 of the high-pressure water injection means 430 is located at the point where the horizontal line CT2 meets the center vertical line CT1 of the second housing 414 to which the abrasive supply means 450 is connected. It is advantageous to ingress through the suction of abrasive.

That is, if the high-pressure water jet nozzle is too down or above, it may interfere with the inflow of the abrasive into the negative pressure space (T) or may cause a problem that the negative pressure space is too wide.

Next, as shown in Figures 5 and 6, the high pressure water injection means 430 of the slurry injection unit 400 of the present invention, is assembled to the first housing 412 side of the device housing 410 and the high pressure water The high pressure water supply port 432 to which the supply pipe 436 is connected, and the high pressure water assembled at the lower end of the high pressure water supply port 432 to spray the inside of the housing to form negative pressure and increase water and abrasive mixing characteristics. Injection nozzle 434.

Therefore, in the case of the slurry injection unit 400 of the present invention, it is not limited to supplying the high pressure water to the interior of the housing 410, but adopting a double injection method of injecting the high pressure water from the interior of the housing 410. Therefore, the high pressure water injection pressure facilitates suction injection of the abrasive into the housing without external pressurization, and the high pressure water spray facilitates mixing of the abrasive, ie, glass beads or ceramic beads and water (high pressure water) (W). .

At this time, the high pressure water supply port 432 may be assembled to the housing and the high pressure water injection port 436 by passing through the lock cap 411 of the upper part of the device housing.

Meanwhile, in FIG. 5, reference numeral 'T' denotes a negative pressure space as a space directly under which high pressure water is injected, and reference numeral 'MT' denotes a mixing space in which the high pressure water W and the abrasive C are mixed.

Next, as shown in Figures 5 and 6, the abrasive input means 450 of the present invention, the abrasive input pipe 452 connected to the second housing 414 integrally formed to be inclined on one side of the housing 410. The abrasive C is thus smoothly sucked into the housing by the negative pressure formed by the injection of high pressure water inside the housing.

Next, as shown in FIGS. 5 and 6, the slurry spraying means 470 of the present invention is assembled inside the third housing 416 opened to the lower portion of the housing 410, and the set bolt 482 is disposed. Slurry injection hole 472, which is a cylindrical body fixed through, a concave depression 474 for additionally mixing high pressure water and abrasive material in the injection hole to discharge in a uniform distribution, and a slit structure through the injection hole from the depression It includes a slurry injection hole 476 provided to.

Accordingly, the slurry S in which the high pressure water and the abrasive are mixed in the mixing space MT is collected at the depression 474 concave toward the center of the injection hole 472 and is moved to the outside through the slurry injection hole 476 of the slit structure. It is injected at high pressure and high speed, and the slurry injected by the injection hole of the slit is sprayed while spreading with a length.

At this time, as shown in Figure 6, it is preferable to form a cutout 478 of a predetermined angle (Θ) on both sides of the lower portion of the injection hole 476 of the slit structure, such a cutout 478 is injected The slurry (slurry stream) S spreads more widely, making it possible to remove the scale of the steel sheet (SC in FIG. 5) more smoothly and in a larger area.

Actually, as shown in Figure 2, the slurry injection unit 400 of the present invention is arranged in a plurality of steel sheet width and length direction of the unit housings, the sprayed slurry is sprayed to overlap a portion.

At this time, the angle of the incision is preferably about 15 to 30 °, excessively narrow or wide angle causes a problem of less effect of the incision or slurry is dispersed. 5 and 6, reference numeral 480 is a fixing ring.

Next, in FIG. 5 and FIG. 6, a mixing means 490 for further inducing mixing of the high pressure water injected into the housing and the introduced abrasive may be installed. For example, the mixing means 490 may be provided in a structure in which lattice nets or rods are connected to the circular ring, as shown in FIG. 6, and preferably, two stages of mixing of rods or wire meshes arranged in different directions. The means 490 are provided with the crosspieces in a staggered direction.

Therefore, as shown in FIG. 5, the slurry S passing through the mixing space MT is further mixed with water and abrasive while passing through the mixing means 490 that is a lattice frame, which is abrasive in the slurry S sprayed onto the steel sheet. As a result, as shown in FIG. 5, when the slurry S (stream) is sprayed onto the steel sheet and collided with it, the abrasive has an even distribution and collides evenly with the surface of the steel sheet, which makes the roughness of the steel sheet uniform. will be.

Next, in FIG. 5, the slurry S used in the slurry spray unit 400 of the scale removing apparatus 100 of the present invention described above, in particular, the reuse of the abrasive, the scale SC peeled from the steel sheet and the broken abrasive (glass (Bead processing) is shown.

That is, as shown in Figures 2 and 5, the high pressure water supply pipe 436 and the abrasive input pipe 452 of the slurry injection unit 400 arranged in the chamber 402, respectively, and the high pressure water supply line (L1) and The abrasive feed line L2 is connected.

At this time, as shown in Figure 5, the lower side of the chamber 402 is provided with a collecting hopper 510 for collecting the water and the abrasive and the peeled scale of the sprayed slurry, the collection hopper is a pump (PP) and the valve (V) The collected scale SC and the used abrasive C are introduced into the separation tank 516 linked to the cyclone 512 and linked to the lower portion of the cyclone 512.

Through the screen (unsigned) in the separation tank, the water is collected in the water reservoir 438 below, the water reservoir 438 is connected to the high-pressure water supply means 430 through the line (L1), abrasive (C ) Is supplied to the abrasive supply hopper 456 connected to the input pipe 452 of the abrasive input means 450 and the supply line (L2), the transfer equipment 454 for supplying a new abrasive is disposed on the upper side of the supply hopper In the lower part of the hopper, a screw feeder 458 for quantitative dispensing of the abrasive is operated.

On the other hand, in the separation tank 516, suspended scales and broken abrasives, etc. are introduced into the processing tank 514 through the overflow, where the abrasives such as scales and broken glass beads are separated from the magnet separator 518 and separated from the abrasives. It is scaled.

Therefore, as shown in FIG. 5, the slurry spray unit 400 of the scale removing apparatus of the present invention, through the associated abrasive and water and scale reprocessing and supply circulation facilities, the treatment of the scale and damaged abrasive or recycling of the abrasive It is possible.

At this time, although not shown with a separate sign in Figure 5, the recycled abrasive collected in the separation tank may be supplied to the abrasive supply hopper 456 in a dried state through a dryer (dashed line).

In addition, as shown in Figure 5, the interval between the steel sheets at the slurry injection point of the slurry injection means 470 can be adjusted in conjunction with the hydraulic cylinder (not shown) in conjunction with the housing of the injection unit, preferably about 100 ~ 350mm,

For example, the spacing between the spraying point and the steel sheet affects the scale removal performance and the removal width. When it is 100 mm or less, the scale removal width is narrowed and the number of installations of the injection unit for the scale treatment is required. The spacing is so wide that the descaling performance is weak.

On the other hand, the embodiments through the descaling apparatus 100 of the present invention described so far as an example will be described.

(Example 1)

The low carbon hot rolled steel sheet (thickness 2.3 mm x width 1200 mm) was continuously flown using the present invention of FIG. 2 with the line speed of 120 mpm under the processing conditions shown in the table below. Silver levels of less than 1% and average surface roughness of 1.2 μm were obtained (1.2 to 1.5 μm for pickled steel sheets).

division Treatment condition Low temperature cooling Water and alcohol 1: 1 solution, temperature -50 ^o C Scale breaker Elongation 1.2%, Bending 25mm Slurry high pressure spraying Abrasive (glass beads, particle size 150 ~ 200 ㎛), slurry injection pressure 200 bar Injection condition Spray angle 15 °, steel plate spacing 230mm

(Example 2)

A high strength hot rolled steel sheet (thickness 3.0 mm x 1200 mm width) containing 0.1% carbon, 0.8% silicon, and 1.2% manganese was used at a line speed of 110mpm as shown in FIG. Compared with the hot-rolled steel sheets of the same steel grades treated, the residual scales had a similar level of less than 1% and an average surface roughness of 1.5 μm.

division Treatment condition Low temperature cooling Alcohol solution, temperature -70 ^o C Scale breaker Elongation 2%, Bending 25mm Slurry high pressure spraying Abrasive (alumina, 100 ㎛), slurry spray pressure 150 bar, Injection condition Spray angle 30 °, spacing between steel plates 280mm

(Example 3)

The low-carbon hot-rolled steel sheet (thickness 2.5mm × width 1340mm) was continuously flown in the process shown in Fig. 2 at a line speed of 120mpm under the conditions shown in the table below. Less than%, an average surface roughness level of 1.5 μm was obtained.

division Treatment condition Low temperature cooling Water and alcohol 1: 1 solution, temperature -80 ^o C Scale breaker Elongation 3.0%, Bending 30mm Slurry high pressure spraying Abrasive (glass beads, 80 μm), slurry spraying pressure 300 bar, Injection condition Spray Angle 23 °, Spacing Between Steel Plates 150mm

Meanwhile, as shown in FIG. 2, the steel sheet 102 passing through the slurry spray unit 400 removes the residual slurry from the washing tank 600, is dried in the dryer 700, and finally wound up in the tension reel 130. To be provided as a product.

In addition, in FIG. 7, a plurality of pumps PP or electrically controllable control valves V installed in a pipe or a line may be provided.

100 ... Descaling device 200 ... Cooling bath
210 .... cooling chamber chamber 230 .... steel sheet feed roll
250 .... Heating means 270 .... Device control
300 .... Breaker 400 .... Slurry Injection Unit
410 ... housing 430 ... high pressure water jet
450 .... Abrasive injection means 470 .... Slurry injection means
490 .... Mixing means C ... Abrasives (glass beads)
S .... slurry (water + abrasive) PP .... pump
V .... Valve

Claims (12)

A cooling tank 200 provided on the conveying path of the steel sheet; and a scale breaker 300 provided downstream of the cooling tank 200; And a slurry injection unit 400 provided to remove the scale on the downstream side of the scale breaker 300.
The cooling tank 200 is provided with inlets and outlets 212 and 214 provided with steel sheet conveying guide rolls 232 through which the steel sheet passes, filled with a refrigerant 216 for cooling the steel sheet, and controlling temperature. Cooling tank chamber 210 is provided with a heating means 250 for, and a plurality of steel sheet feed roll 230 provided in the cooling tank chamber 210 to provide a coolant deposition transfer of the steel sheet,
The slurry injection unit 400, the housing 410 disposed in the chamber 402 corresponding to the traveling path of the steel sheet and the high pressure water injection means 430 provided to the housing, and one side of the high pressure water injection means A slurry injection means 450 provided in the housing and a slurry injection means 470 provided to spray the polishing slurry (S) mixed with a high-pressure water and the abrasive in the lower portion of the housing to the steel sheet,
The slurry spraying means 470 includes an injection hole 472 assembled to a lower portion of the housing, a depression 474 formed by mixing the high pressure water and the abrasive with the injection hole, and through the injection hole from the depression. A slurry injection hole 476 provided in a slit structure and a mixing means 490 provided with a grid or rods in a circular ring to induce mixing of the high pressure water injected into the housing with the introduced abrasive. Descaling device.
delete The method of claim 1,
The refrigerant 216 is provided as a liquid containing water and alcohol, or an alcohol solution to which liquid nitrogen is supplied through the liquid nitrogen supply port 218 provided in the cooling chamber chamber, and having a temperature of -10 ° C to -100 ° C. Descaler, characterized in that to maintain.
delete delete The method of claim 1,
The high pressure water injection means 430, the high pressure water supply port 432 is assembled to the upper portion of the device housing is supplied with high pressure water;
A high pressure water nozzle 434 assembled to the high pressure water supply port 432 so as to spray high pressure water in the housing;
And a scale removing unit configured to remove the scale.
The method of claim 1,
The abrasive injection means 450, including the abrasive injection pipe 452 connected to the housing 410, the abrasive (C) is configured to be sucked into the housing by the negative pressure formed by the injection of high pressure water in the housing Descaler.
delete delete The method of claim 1,
Wherein said abrasive is formed of one of silicon oxide, silicon carbide, aluminum oxide, glass, and ceramic having a smaller specific gravity than metal. delete delete

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