JP2012152761A - Equipment and method for descaling thick steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide equipment and a method for descaling a thick steel plate, by which descaling is performable over the whole surface in the width direction of the thick steel plate and the thick steel plate having small variations in the material is made manufacturable by performing uniform cooling when performing the descaling of the thick steel plate after hot rolling.SOLUTION: In the equipment 4 for descaling the steel plate after hot rolling, the descaling equipment 4 is installed on the downstream side in the conveyance direction from a pre-leveler (first hot straightening machine) 3, and on the upstream side of an accelerated cooling equipment 5 and not less than two headers which comprise the descaling equipment 4 are arranged in a line in the conveying direction and the colliding positions of descaling water jetted from each header onto the steel plate are separated by 600 mm or more in the conveyance direction.

Description

  The present invention relates to a descaling equipment and a descaling method for a thick steel plate.

  In the process for producing a thick steel plate, for example, in a production facility (production line) as shown in FIG. 1, the slab is heated in the heating furnace 1 and hot rolled (rough rolling, finish rolling) in the rolling mill 2. The organization is controlled by water cooling or air cooling in the accelerated cooling equipment 5. When cooled to a relatively low temperature, for example, about 450 to 650 ° C. by water cooling, fine ferrite and bainite structure can be obtained and the strength of the thick steel plate (hereinafter also simply referred to as “steel plate”) can be secured. A technique for cooling a steel sheet with laminar cooling water or the like is common. In recent years, the development of techniques for obtaining a high cooling rate, making the structure finer, and increasing the strength of the steel sheet has been active.

  It is known that the cooling rate of a steel plate increases as the surface scale thickness increases. Therefore, as in Patent Document 1, after finishing rolling, the steel sheet is straightened and descaled to make the scale uniformly thinner and then cooled with water, so that the cooling rate in the steel sheet surface is made uniform and the product of uniform material is obtained. There is technology to try to get.

  Further, in order to perform uniform descaling in the width direction of the steel plate (hereinafter also simply referred to as “width direction”), as in Patent Document 1, it is injected from a descaling nozzle (hereinafter also simply referred to as “nozzle”). There is a technique for eliminating the scale peeling defect by making the flow rate of the high-pressure water different in the width direction end, the center, and the other end.

  Incidentally, in FIG. 1, a pre-leveler (first hot straightening machine) 3 and a descaling equipment 4 are installed in order to perform straightening and descaling of the steel sheet after hot rolling in the rolling mill 2. In addition, a hot leveler (second hot straightening machine) 6 is installed in order to straighten the steel sheet after cooling in the accelerated cooling facility 5.

JP 2006-247714 A

  However, the conventional technique as described in Patent Document 1 has a problem that descaling over the entire surface of the steel sheet cannot always be performed appropriately.

  FIG. 11 shows a side view of the descaling equipment for thick steel plates in the prior art as described in Patent Document 1.

  As shown in FIG. 11, in the prior art, in the descaling equipment 4 installed on the upstream side in the steel plate transport direction of the accelerated cooling equipment 5, one (one row) descaling header (upper row) in the steel plate 10 transport direction A descaling header 11 and a lower descaling header 13) are provided. An upper descaling nozzle 12 is attached to the upper descaling header 11, and a lower descaling nozzle 14 is attached to the lower descaling header 13.

  The accelerated cooling facility 5 includes an upper surface laminar cooling header 21, an upper laminar nozzle 22, a lower surface laminar cooling header 23, a lower laminar nozzle 24, and a draining roll 26. In FIG. 11, 25 is a staying cooling water, and 31 is a table roller.

  In such a conventional technology, in order to increase the descaling capability, when multiple descaling headers (a plurality of rows) are arranged in the steel plate transport direction, the descaling header injected from the descaling header installed downstream in the transport direction is used. After scaling water collides with the steel sheet, it flows upstream and interferes with descaling water injected from the descaling header installed upstream in the transport direction, resulting in reduced descaling performance and preventing uniform descaling. There is.

  Further, in the prior art, with respect to the steel plate on the pass line, the injection range (injection region, collision region) of each descaling nozzle is 10 in the width direction with the injection range (injection region, collision region) of the adjacent descaling nozzle. However, if the steel plate is greatly warped, the collision area of each descaling nozzle will not wrap in the width direction on the steel plate away from the pass line, and uniform descaling will be possible. There is a problem of disappearing.

  That is, as shown in FIG. 12A, if the steel plate 10 is completely flat and is located on the pass line, each descaling nozzle (up descaling) is applied to the steel plate 10 (10a). The collision area of the jet water (descaling water) from the nozzle 12 and the lower descaling nozzle 14 wraps all in the width direction (wrap portion 15), and uniform descaling can be performed. However, for example, as shown in FIG. 12 (b), when the steel plate 10 is largely warped (warp amount δ), the descaling nozzle on the upper surface side of the steel plate 10 (10b) at a portion away from the pass line. 12 and the upper surface of the steel plate 10b are shortened, and a portion (non-collision portion 16) where the spray water (descaling water) from the upper descaling nozzle 12 does not collide becomes a part in the width direction and is uniform. Cannot be scaled properly. The same applies to the case where the shape of the steel plate 10 is bad. When the spray distance of the descaling nozzles 12 and 14 is shortened, uniform descaling cannot be performed.

  If uniform descaling cannot be performed in this manner, uniform cooling cannot be performed, so that there is a problem that temperature unevenness increases in the steel sheet surface and the material varies greatly.

  The present invention has been made in view of the above circumstances, and when performing descaling of a thick steel plate after hot rolling, the descaling can be performed over the entire width direction of the thick steel plate, and uniform cooling is performed. It is an object of the present invention to provide a thick steel plate descaling facility and a descaling method that can manufacture a thick steel plate with small material variations.

  In order to solve the above problems, the present invention has the following features.

  [1] A descaling facility for a thick steel plate after hot rolling, wherein the descaling facility is located downstream of the hot straightening machine in the transport direction and upstream of the accelerated cooling facility. Descaling of a thick steel plate, characterized in that two or more headers constituting the structure are arranged side by side in the transport direction, and the collision position of the descaling water sprayed from each header to the steel plate is 600 mm or more apart in the transport direction Facility.

  [2] Above the thick steel plate between two or more headers arranged in the transport direction, the descaling water sprayed from each upper surface header extends in the thick steel plate width direction for collecting scattered water after colliding with the steel plate. The steel plate descaling apparatus according to [1], wherein a ridge is provided, and a side wall of the ridge is inclined 5 to 25 ° inward in the vertical direction.

[3] The nozzle pitch Lp in the width direction of each header is
n · Lw / 2 <Lp ≦ n · Lw (H−δ) / H
The thick steel plate descaling facility according to [1] or [2], wherein:
Here, n: the number of headers in the transport direction, Lw: the collision area width in the steel plate width direction per nozzle for the steel plate in the pass line, H: the height from the steel plate in the pass line to the nozzle tip, δ: Maximum amount of warpage generated in thick steel plate

  [4] The thick steel plate descaling facility according to [3], wherein the collision region of each nozzle is formed at an angle of 90 ° with respect to the transport direction of the thick steel plate.

  [5] A method for descaling a thick steel plate after hot rolling, wherein the descaling equipment is installed downstream of the hot straightening machine in the transport direction and upstream of the accelerated cooling equipment, Thickness characterized by arranging two or more headers to be arranged side by side in the transport direction and spraying the descaling water so that the collision position of the descaling water sprayed from each header to the steel plate is 600 mm or more away in the transport direction Steel sheet descaling method.

  [6] Above the thick steel plates between the headers arranged in two or more in the transport direction, a ridge extending in the width direction of the thick steel plate is provided so that the side wall of the heel is inclined in the vertical direction by 5 to 25 °, The method for descaling a thick steel plate according to [5] above, wherein scattered water after the descaling water sprayed from the top header collides with the steel plate is collected from the top surface of the thick steel plate.

[7] The maximum warpage amount δ generated in the thick steel plate is determined in advance, and the nozzle pitch Lp in the width direction of each header is
n · Lw / 2 <Lp ≦ n · Lw (H−δ) / H
The thick steel plate descaling method according to [5] or [6], wherein the steel plate is arranged so as to satisfy
Here, n: number of headers in the conveying direction, Lw: collision area width in the steel plate width direction per nozzle with respect to the steel plate on the pass line, H: height from the steel plate on the pass line to the nozzle tip

  [8] The thick steel plate descaling method according to [7], wherein the collision region of each nozzle is formed at 90 ° with respect to the thick steel plate conveyance direction.

  By using the present invention, when descaling a thick steel plate after hot rolling, uniform descaling can be performed over the entire surface of the thick steel plate. Thereby, uniform cooling of the entire surface of the thick steel plate can be performed, and a thick steel plate with small variations in material can be manufactured.

It is a figure showing the descaling equipment of the thick steel plate in one Embodiment of this invention, and the manufacturing equipment of the thick steel plate containing it. It is a side view showing the descaling equipment of a thick steel plate in one embodiment of the present invention (two rows of descaling headers are arranged). It is a top view showing the injection state of two rows of descaling headers in one embodiment of the present invention. It is a top view showing the state which a descaling defect arises when the distance of the conveyance direction of two rows of descaling headers is short. In one Embodiment of this invention, it is a side view showing the state in which upper surface scattered water flows in into a collection tank. It is a side view showing the state where upper surface splash water does not effectively flow into the recovery tank. It is a side view showing the state where upper surface splash water does not effectively flow into the recovery tank. In one Embodiment of this invention, even when there exists a height change of a steel plate, it is a figure showing the state which a descaling part completely wraps. It is a top view showing the injection field in one embodiment of the present invention. It is a side view showing the injection field in one embodiment of the present invention. It is a side view showing the descaling installation in a prior art (a descaling header is arrange | positioned in 1 row). In a prior art, when there exists a height change of a steel plate, it is a figure showing the state which a non-collision part of descaling arises.

  An embodiment of the present invention will be described with reference to the drawings.

  In one embodiment of the present invention, descaling of the thick steel plate after hot rolling is performed in the process of producing the thick steel plate (thick steel plate production line) shown in FIG.

  That is, in this embodiment, in a production facility (production line) as shown in FIG. 1, the slab is heated in the heating furnace 1 and hot rolling (rough rolling, finish rolling) is performed in the rolling mill 2 and then accelerated. The structure is controlled by water cooling or air cooling in the cooling facility 5. At that time, the steel sheet hot rolled by the rolling mill 2 is straightened by the pre-leveler (first hot straightening machine) 3, and descaling equipment. In step 4, descaling is performed. Further, the steel sheet after being cooled by the accelerated cooling equipment 5 is straightened by a hot leveler (second hot straightening machine) 6, but the present invention is not limited to the type of the accelerated cooling equipment 5 or the hot leveler (second hot straightening machine). Machine) It is not limited to the presence or absence of 6.

  And FIG. 2 shows the side view of the descaling equipment of the thick steel plate in this embodiment.

  As shown in FIG. 2, in this embodiment, in the descaling equipment 4 installed on the upstream side in the steel plate transport direction of the accelerated cooling equipment 5, two (two rows) descaling headers ( Upper descaling headers 11a and 11b and lower descaling headers 13a and 13b) are provided. Upper descaling nozzles 12a and 12b are attached to the upper descaling headers 11a and 11b, respectively, and lower descaling nozzles 14a and 14b are attached to the lower descaling headers 13a and 13b, respectively.

  Incidentally, in FIG. 2, two descaling headers are provided in the transport direction of the steel plate 10, but three or more descaling headers may be provided in the transport direction of the steel plate 10. Further, the descaling header may be divided into a plurality of parts in the width direction. For example, a descaling header with a narrow injection width may be disposed at the center in the plate width direction, and a descaling header for a wide steel plate may be disposed on both outer sides thereof.

  The accelerated cooling facility 5 includes an upper surface laminar cooling header 21, an upper laminar nozzle 22, a lower surface laminar cooling header 23, a lower laminar nozzle 24, and a draining roll 26. In FIG. 2, 25 is a staying cooling water, and 31 is a table roller.

  Thus, in this embodiment, since the pre-leveler (first hot straightening machine) 3 corrects the warpage and shape of the steel sheet 10 to some extent, the descaling equipment 4 performs the descaling, so that FIG. As shown, the distance between the descaling nozzle and the top surface of the steel plate is greatly shortened due to large warpage and shape defects, and the part where the descaling water does not collide (non-collision part) can be part of the width direction. Therefore, uniform descaling can be performed by completely wrapping the injection region (collision region) in the width direction.

  Further, in this embodiment, the collision position (collision area) 12A of the descaling water ejected from the descaling nozzle 12a with the steel plate 10 and the collision position (the collision area) 12A of the descaling water ejected from the descaling nozzle 12b ( The distance Lh in the transport direction with the collision area) 12B is set to 600 mm or more.

  In this way, by separating the conveyance direction distance (header interval) Lh of the collision position by 600 mm or more, the descaling water sprayed from the descaling header 11b installed on the downstream side in the conveyance direction as shown in the top view in FIG. Is attenuated until it reaches the collision position 12A of the descaling header 11a installed on the upstream side in the transport direction after colliding with the steel plate 10 at the collision position 12B, so that the descaling injected from the descaling header 11a installed on the upstream side The effect of water interference is reduced.

  On the other hand, when the transport direction distance (header interval) Lh at the collision position is smaller than 600 mm, the descaling water sprayed from the descaling header 11b installed on the downstream side in the transport direction as shown in the top view of FIG. Flows to the upstream side with little attenuation after colliding with the steel plate 10 at the collision position 12B, interferes with the descaling water sprayed from the descaling header 11a installed on the upstream side in the transport direction, and the descaling performance is significantly reduced. .

  Further, in this embodiment, as shown in FIGS. 2 and 5, in order to collect the scattered water 17 after the descaling water sprayed from the upper descaling headers 11 a and 11 b collides with the steel plate 10, the steel plate width A flange 19 extending in the direction is provided between the upper descaling header 11a and the upper descaling header 11b. By providing this collection gutter 19, the scattered water 17 can be collected, the stagnant water on the upper surface of the steel sheet can be reduced, and the decrease in descaling capability can be suppressed. In other words, when the recovery rod 19 is not provided, the amount of staying water increases on the upper surface of the steel sheet, and the descaling water jetted from the descaling headers 11a and 11b is prevented from colliding with the steel sheet surface, and the descaling performance is reduced. descend.

  At that time, it is preferable that the side wall of the collection basket 19 is inclined inward of the basket 19 at an angle of η = 5 to 25 ° in the vertical direction. As shown in FIG. 6, when the angle η of the side wall of the recovery rod 19 is less than 5 ° in the vertical direction, the scattered water 18 that collides with the side wall of the recovery rod scatters back and forth, so that the scattered water 17 cannot be recovered efficiently. . Further, as shown in FIG. 7, when the angle η of the side wall of the recovery rod 19 is larger than 25 ° in the vertical direction, the gap above the recovery rod 19 is small, and the splashed water 18 that has collided with the side wall jumps over the gap. The scattered water 17 cannot be recovered efficiently. More preferably, η = 5 to 15 °.

  Moreover, it is preferable that the clearance gap between the upper surface of the steel plate 10 and the collection basket 19 shall be about 50-200 mm. As described above, in this embodiment, since the pre-leveler (first hot straightening machine) 3 corrects a large warp and shape of the steel sheet 10 to some extent, the descaling equipment 4 performs descaling, so the steel sheet 10 and the recovery are collected. The distance between the flanges 19 can be shortened to about 50 mm. On the other hand, if the distance between the steel plate 10 and the recovery rod 19 exceeds 200 mm, the scattered water 17 cannot be recovered efficiently.

  In addition, in this embodiment, the warp and shape of the steel plate 10 are corrected to some extent by the pre-leveler (first hot straightening machine) 3, the amount of warpage after the correction is grasped, and the amount corresponding to the amount of warpage is determined. By setting the scaling nozzle pitch, the injection region can be completely wrapped in the width direction.

  That is, the width direction pitch Lp of the descaling nozzles 12a and 12b in the descaling headers 11a and 11b satisfies the following expression (1).

n · Lw / 2 <Lp ≦ n · Lw (H−δ) / H (1)
Here, Lw is the injection area width (collision area width) in the steel sheet width direction per one descaling nozzle (one) for the steel sheet in the pass line, and H is the injection height when there is no warpage of the steel sheet (pass line). ) Is the maximum warpage amount of the steel sheet, and n is the number of descaling headers in the steel sheet conveyance direction (here, n = 2).

  At that time, in this embodiment, as shown in the front view in FIG. 8A and the top view in FIG. 8B, when the two descaling headers 11a and 11b are arranged, the upper descaling is performed. The injection pattern (collision area) 12A from the nozzle 12a and the injection pattern (collision area) 12B from the upper descaling nozzle 12b are arranged in a staggered manner.

  Thus, in this embodiment, as shown in FIG. 8, the steel plate 10 warps upward, and the injection height of the upper descaling nozzles 12a, 12b with respect to the steel plate 10b of the warped portion starts from H. When shortened to H−δ, the upper descaling headers 12a and 12b have respective upper descaling headers so that the collision area width in the width direction can be reduced from Lw to Lw (H−δ) / H. By setting the nozzle pitch Lp in 11a and 11b to 2 · Lw (H−δ) / H or less, the nozzle pitch Lp / 2 when viewed in the descaling device 4 as a whole becomes Lw (H−δ) / H or less, Even when the steel plate 10 is warped, a non-collision portion is not generated in the width direction of the warped steel plate 10b.

  In addition, if the nozzle pitch Lp in each of the upper descaling headers 11a and 11b is larger than the ejection area width Lw in the width direction per descaling nozzle for the steel plate in the pass line, the jetting is performed when the steel plate 10 is not warped. Even if the nozzles 12a and 12b are installed at an angle of 90 ° with respect to the transport direction, the spray water from the adjacent nozzles can reach the steel plate 10 without hitting in the air. Descaling is possible without interference with the water jet.

  On the other hand, when the nozzle pitch Lp is n · Lw / 2 or less, when there is no warpage of the steel plate 10, the descaling water is jetted to the full width of the steel plate in one row of the descaling header, and the adjacent descaling nozzles Not only is it interfered with the jet water, but the amount of water used also increases, which increases the equipment cost. Therefore, the nozzle pitch Lp is set to exceed n · Lw / 2.

  In addition, the spray area from each descaling nozzle is preferably formed at an angle of θ = 75 to 90 ° with respect to the steel plate conveyance direction, but in this embodiment, they are adjacent as shown in FIG. Θ = 90 ° is the best because there is no wrapping or interference from the nozzle spray water.

  Further, as shown in FIG. 10, the descaling water is preferably injected at an angle of φ = 5 ° to 15 ° from the vertically downward direction so as to face the steel plate conveyance direction. If the angle φ is smaller than 5 °, the back flow of the spray water (descaling water) of the second upper descaling header 11b is large, the scale is caught by the draining roll 26 on the downstream side in the transport direction, and the steel plate 10 or draining roll There is a possibility that a problem of wrinkling 26 occurs. On the other hand, if the angle φ is greater than 15 °, the injection distance becomes longer, the collision pressure is reduced, and the back flow of the water (descaling water) of the first upper descaling header 11a becomes too small. As a result, the second upper descaling header 11b becomes more susceptible to the interference of the jet water, and the descaling performance is significantly degraded.

  The pitch in the width direction of the descaling nozzle is not necessarily the same on the upper surface side and the lower surface side of the steel plate 10. For example, if the steel plate 10 tends to warp upward as a characteristic of the production line, the pitch of the descaling nozzle on the upper surface side may be set smaller than the pitch of the descaling nozzle on the lower surface side.

  Examples of the present invention will be described.

  In this example, the slab extracted from the heating furnace 1 was hot-rolled (coarse rolling and then finish-rolled) by the rolling mill 2 in the thick steel plate manufacturing facility shown in FIG. The product steel plate had a plate thickness of 20 mm, a plate width of 3.2 m, and a target strength of 590 MPa or more. After finishing rolling by the rolling mill 2, the shape was corrected by the pre-leveler (first hot straightening machine) 3, and then descaling was performed by the descaling equipment 4.

  At that time, when the distance between the steel plate in the pass line and the descaling nozzle is 90 mm and the angle θ formed by the injection region with respect to the transport direction is 90 °, the width of the injection region in the width direction with respect to the steel plate in the pass line Lw was 80 mm, and the collision pressure on the surface of the steel plate 10 was 1.5 MPa.

  And after performing the descaling by the descaling equipment 4 with respect to the steel plates A, B, C, and D having the tip warpage amounts of 0 mm, 10 mm, 20 mm, and 30 mm, respectively, the Ar3 transformation point by the accelerated cooling equipment 5 From the above temperature, accelerated cooling was performed until the average thickness of the plate reached 500 ° C.

  Table 1 shows the implemented conditions and results.

  First, as Example 1 of the present invention, descaling was performed based on the above-described embodiment of the present invention. That is, when performing descaling using a descaling facility in which two descaling headers are installed in the transport direction as shown in FIG. 2, the header interval Lh is set to 800 mm. In addition, the angle θ formed by the injection region with respect to the transport direction is 80 °, and the injection region width Lw in the width direction with respect to the steel plate in the pass line is 78.8 mm, so that the nozzle pitch is satisfied so as to satisfy the expression (1). Lp was 75 mm. There was no recovery dredge installed.

  As a result, in Example 1 of the present invention, the descaling water ejected from the header installed on the downstream side in the transport direction is descaled water ejected from the header installed on the upstream side in the transport direction by setting the header interval Lh to 800 mm. In other words, all the steel plates A to D were uniformly cooled on the entire surface of the steel plate. For this reason, the dispersion | variation in the intensity | strength of the width direction of the thick steel plate obtained even if accelerated cooling to 500 degreeC was as small as 30 MPa.

  In addition, as Invention Example 2, a recovery tank was further installed under the same conditions as in Invention Example 1 described above. At that time, the side wall angle η = 5 ° of the recovery rod was used.

  As a result, in Example 2 of the present invention, since the scattered water on the upper surface of the steel plate was recovered, the descaling water sprayed from the header installed downstream in the transport direction was descaled from the header installed upstream in the transport direction Water no longer interferes, and all of the steel plates A to D can be uniformly cooled on the entire surface of the steel plate. For this reason, the dispersion | variation in the intensity | strength of the width direction of the thick steel plate obtained even if accelerated cooling to 500 degreeC was further reduced with 20 MPa.

  Further, as Invention Example 3, the injection region is transported under the same conditions as in Invention Example 2 except for the angle θ that the injection region makes with the transport direction, the injection region width Lw in the width direction, and the nozzle pitch Lp. The angle θ formed with the direction was set to 90 °, the injection region width Lw was set to 80 mm, and the expression (1) was satisfied, and the nozzle pitch Lp was set to 100 mm.

  As a result, in Example 3 of the present invention, all of the steel plates A to D could be uniformly cooled over the entire surface of the steel plate, and the scattered water on the upper surface of the steel plate could be recovered. For this reason, the dispersion | variation in the intensity | strength of the width direction of the thick steel plate obtained even if accelerated cooling to 500 degreeC was further reduced with 20 MPa. In addition, descaling could be performed with a smaller number of nozzles and flow rate than Example 2 of the present invention.

  On the other hand, as Comparative Example 1, descaling was performed using a descaling facility in which one descaling header was installed in the transport direction as shown in FIG. At that time, in order to wrap the injection region in the width direction, the angle θ formed by the injection region with respect to the conveyance direction is 75 °, and the injection region width Lw in the width direction with respect to the steel plate in the pass line is 77.3 mm. The nozzle pitch Lp was 75 mm.

  As a result, in Comparative Example 1, the steel plate B, steel plate C, and steel plate D that did not satisfy the formula (1) and had warpage did not wrap in the width direction, and there was some scale residue. . For this reason, temperature unevenness occurred by accelerated cooling, and the variation in strength in the width direction of the obtained thick steel plate was as large as 60 MPa.

  As Comparative Example 2, when performing descaling using a descaling facility in which two descaling headers are installed in the transport direction as shown in FIG. 2, the header interval Lh is set to 250 mm. In addition, the angle θ formed by the injection region with respect to the transport direction was 90 °, the injection region width Lw in the width direction with respect to the steel plate in the pass line was 80 mm, and the nozzle pitch Lp was 100 mm. There was no recovery dredge installed.

  As a result, in Comparative Example 2, since the header interval Lh is 250 mm, the descaling water ejected from the header installed downstream in the transport direction interferes with the descaling water ejected from the header installed upstream, and warps. There was some scale residue in steel plates B to D. For this reason, temperature unevenness was generated by accelerated cooling, and the strength variation in the width direction of the obtained thick steel plate was as large as 60 MPa.

  From the above results, the descaling header is installed at a distance of 600 mm or more in the conveying direction, and preferably a thick steel plate is provided between the headers by providing a ridge extending in the width direction above the thick steel plate to collect the scattered water on the upper surface of the thick steel plate. It was found that uniform descaling can be performed over the entire surface. Furthermore, the maximum warpage amount generated in the thick steel plate is grasped in advance, and the nozzle pitch in the width direction of the descaling header is determined so as to satisfy the equation (1). However, it was found that uniform descaling can be performed over the entire surface of the thick steel plate, and this confirmed the effectiveness of the present invention.

1 Heating furnace 2 Rolling machine 3 Pre-leveler (1st hot straightening machine)
4 Descaling equipment 5 Accelerated cooling equipment 6 Hot leveler (second hot straightening machine)
10 Steel plate (thick steel plate)
10a Steel plate in the pass line 10b Steel plate in the upper part away from the pass line 11 Upper descaling header 11a First row (first) upper descaling header 11b Second row (second) upper descaling header 12 Descaling nozzle 12a First (first) upper descaling nozzle 12b Second (second) upper descaling nozzle 12A First (first) upper descaling nozzle collision area 12B Second row ( Collision area of upper second descaling nozzle 13 Lower descaling header 13a Lower descaling header of first row 13b Lower descaling header of second row 14 Lower descaling nozzle 14a Lower descaling nozzle of first row 14b Lower descaling nozzle of second row 15 Lap section 16 Non-collision section 17 Fly Sprinkling water 18 Splashing water colliding with side wall 19 Collecting water 21 Upper surface laminar cooling header 22 Upper laminar nozzle 23 Lower surface laminar cooling header 24 Lower laminar nozzle 25 Stagnating cooling water 26 Draining roll 31 Table roller

Claims (8)

  It is a descaling equipment for a thick steel plate after hot rolling, and the descaling equipment is on the downstream side in the transport direction from the hot straightening machine and on the upstream side of the accelerated cooling equipment, and constitutes the descaling equipment A descaling facility for thick steel plates, wherein two or more headers are arranged side by side in the transport direction, and the collision position of the descaling water sprayed from each header with the steel plate is 600 mm or more apart in the transport direction.   A trough extending in the width direction of the thick steel plate is provided above the thick steel plate between the headers arranged in the transport direction, in order to collect the scattered water after the descaling water sprayed from each top header collides with the steel plate. The thick steel plate descaling equipment according to claim 1, wherein a side wall of the ridge is inclined 5 to 25 ° inward in the vertical direction. The nozzle pitch Lp in the width direction of each header is
n · Lw / 2 <Lp ≦ n · Lw (H−δ) / H
The descaling equipment for thick steel plates according to claim 1 or 2, wherein:
Here, n: the number of headers in the transport direction, Lw: the collision area width in the steel plate width direction per nozzle for the steel plate in the pass line, H: the height from the steel plate in the pass line to the nozzle tip, δ: Maximum amount of warpage generated in thick steel plate   4. The steel plate descaling equipment according to claim 3, wherein the collision area of each nozzle is formed at 90 [deg.] With respect to the steel plate conveyance direction.   A method for descaling a thick steel plate after hot rolling, wherein the descaling equipment is installed downstream of the hot straightening machine in the transport direction and upstream of the accelerated cooling equipment, and constitutes the descaling equipment The descaling water is sprayed so that the collision position of the descaling water sprayed from each header with the steel plate is separated by 600 mm or more in the transport direction. Scaling method.   Above the thick steel plates between the headers aligned in the transport direction, a ridge extending in the width direction of the thick steel plate is provided so that the side walls of the ridges are inclined inward by 5 to 25 ° in the vertical direction. 6. The method of descaling a thick steel plate according to claim 5, wherein the scattered water after the sprayed descaling water collides with the steel plate is collected from the upper surface of the thick steel plate. The maximum warpage amount δ generated in the thick steel plate is determined in advance, and the nozzle pitch Lp in the width direction of each header is
n · Lw / 2 <Lp ≦ n · Lw (H−δ) / H
It arrange | positions so that it may satisfy | fill.
Here, n: number of headers in the conveying direction, Lw: collision area width in the steel plate width direction per nozzle with respect to the steel plate on the pass line, H: height from the steel plate on the pass line to the nozzle tip   The method for descaling a thick steel plate according to claim 7, wherein the collision region of each nozzle is formed at an angle of 90 ° with respect to the conveying direction of the thick steel plate.

Images