US20090108509A1 - Cooling Apparatus of Thick-Gauge Steel Plate - Google Patents

Cooling Apparatus of Thick-Gauge Steel Plate Download PDF

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Publication number
US20090108509A1
US20090108509A1 US11/922,715 US92271505A US2009108509A1 US 20090108509 A1 US20090108509 A1 US 20090108509A1 US 92271505 A US92271505 A US 92271505A US 2009108509 A1 US2009108509 A1 US 2009108509A1
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Prior art keywords
steel plate
thick
gauge steel
spray nozzles
surface side
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Abandoned
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US11/922,715
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English (en)
Inventor
Yoshihiro Seruzawa
Ryuji Yamamoto
Hisayoshi Matsunaga
Shigetru Ogawa
Yataka Akase
Hironori Ueno
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Nippon Steel Corp
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Nippon Steel Corp
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Priority claimed from JP2005182898A external-priority patent/JP4214134B2/ja
Application filed by Nippon Steel Corp filed Critical Nippon Steel Corp
Assigned to NIPPON STEEL CORPORATION reassignment NIPPON STEEL CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: AKASE, YUTAKA, MATSUNAGA, HISAYOSHI, OGAWA, SHIGERU, SERIZAWA, YOSHIHIRO, UENO, HIRONORI, YAMAMOTO, RYUJI
Publication of US20090108509A1 publication Critical patent/US20090108509A1/en
Assigned to NIPPON STEEL & SUMITOMO METAL CORPORATION reassignment NIPPON STEEL & SUMITOMO METAL CORPORATION MERGER (SEE DOCUMENT FOR DETAILS). Assignors: NIPPON STEEL CORPORATION
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
    • B21B45/0203—Cooling
    • B21B45/0209—Cooling devices, e.g. using gaseous coolants
    • B21B45/0215—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes
    • B21B45/0218—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes for strips, sheets, or plates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
    • B21B45/0203—Cooling
    • B21B45/0209—Cooling devices, e.g. using gaseous coolants
    • B21B45/0215—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes
    • B21B45/0233—Spray nozzles, Nozzle headers; Spray systems

Definitions

  • the present invention relates to a cooling apparatus of thick-gauge steel plate used in the case of cooling finished thick-gauge steel plate when producing thick-gauge steel plate by hot rolling.
  • the top surface side line of nozzles 11 s used in the cooling disclosed in Japanese Patent Publication (A) No. 11-347629 is comprised of one line of slit nozzles long in the steel plate width direction. Further, the bottom surface side line of nozzles 12 s is comprised of either slit nozzles, spray nozzles, tubular laminar nozzles, tubular spray nozzles with guide pipes, or multihole nozzles.
  • one line of slit nozzles is arranged at the top surface side, a plurality of lines of slit nozzles, tubular spray nozzles with guide pipes, tubular laminar nozzles, etc. are arranged over a broad region at the bottom surface side, and the entire region of the bottom surface side of the steel plate is sprayed uniformly with cooling water w without regard as to the position with respect to the top surface side line of nozzles and the regions with plate top water present.
  • the cooling ability is large and stable at the parts which the water sprays strike, but is small at the parts where plate top water flows. This is because the cooling ability with respect to steel plate differs between the case where the water sprays strike from the vertical direction and the case where water flows in parallel along the steel plate.
  • the area of the water spray impact parts from the lines of spray nozzles arranged positioned facing the top surface side and bottom surface side is made 60% or more of the area of the thick-gauge steel plate area between the constraining rolls 5 1 , 5 2 , in particular, at the top surface side, the case where the area of the large thick-gauge steel plate between the constraining rolls 5 1 , 5 2 is substantially covered by the water spray impact surfaces is included.
  • a flow resulting from the discharge of the impacting cooling water and interfering convection parts where the sprays interfere and convect are formed unevenly in the width direction of the thick-gauge steel plate. As a result, there is a concern that the cooling efficiency will drop and the cooling will become uneven.
  • the cooling apparatus of thick-gauge steel plate of the present invention has as its gist the constitutions as set forth in the following (1) to (4) so as to efficiently realize uniform cooling of thick-gauge steel plate (in particular uniform cooling of the top and bottom surfaces):
  • a cooling apparatus of thick-gauge steel plate having a plurality of pairs of constraining rolls, each comprising a top roll and bottom roll, constraining and conveying hot rolled thick-gauge steel plate and a plurality of spray nozzles spraying water on the top and bottom surfaces of the thick-gauge steel plate conveyed between the adjoining pairs of constraining rolls before and after each other in the conveyance direction,
  • the sum of the areas of the impact surfaces of the water sprays from the top surface side spray nozzles on the surface of the thick-gauge steel plate is in the range of 4 to 90% of the surface area of the steel plate between the roll outer circumferences at the closest distance between the pairs of constraining rolls and
  • a cooling apparatus of thick-gauge steel plate as set forth in (1) characterized by arranging said top surface side and bottom surface side spray nozzles so that:
  • the present invention by selecting the ratio (%) between the sum of the areas of the impact surfaces of the water sprays with the surface of the thick-gauge steel plate in the distance (La) between the roll outer circumferences at the closest distance between the pairs of constraining rolls to be within a prescribed range at the top surface side and bottom surface side of the thick-gauge steel plate, it is possible suppress the uneven formation of pools of impacting spray on the thick-gauge steel plate and thereby stably secure cooling efficiently and achieve uniform temperature of the thick-gauge steel plate after cooling (in particular, secure symmetry of temperatures at the top and bottom surfaces).
  • the range of adjustment of the amounts of water can be expanded and further the impact forces of the water sprays can be easily adjusted, so the range of cooling control can be broadened.
  • the phenomenon of the impact forces of water sprays against thick-gauge steel plate becoming weaker in the case of reducing the amounts of water can be eased and the desired cooling ability can be easily stably secured.
  • FIG. 1 is a view showing one example of the arrangement of facilities provided with thick-gauge steel plate cooling apparatuses of the present invention.
  • FIG. 2 is a view showing a thick-gauge steel plate cooling apparatus of Example 1 of the present invention.
  • FIG. 6 is a view showing a thick-gauge steel plate cooling apparatus of Example 2 of the present invention.
  • (a) shows a side surface of a thick-gauge steel plate cooling apparatus.
  • (b) shows a front surface of a thick-gauge steel plate cooling apparatus.
  • (c) shows an arrangement of nozzles in the bottom surface side cooling apparatus.
  • FIG. 7A is a view showing a thick-gauge steel plate cooling apparatus of Example 3 of the present invention.
  • (a) shows a side surface of the thick-gauge steel plate cooling apparatus.
  • (b) shows the front surface of the thick-gauge steel plate cooling apparatus.
  • FIG. 7B is a view showing an arrangement of nozzles at a thick-gauge steel plate cooling apparatus shown in FIG. 7A .
  • (a) shows an arrangement of nozzles at a top surface side cooling apparatus.
  • (b) shows an arrangement of nozzles of a bottom surface side cooling apparatus.
  • FIG. 9 is a view showing a conventional steel plate cooling apparatus.
  • FIG. 10 is a view showing another conventional steel plate cooling apparatus.
  • FIG. 11 is a view showing cooling regions and an array of nozzles in the conventional steel plate cooling apparatus shown in FIG. 10 .
  • FIG. 12 gives views showing the impact pressure distribution and cooling ability (cooling rate) in the case of spraying water under conditions of a nozzle discharge pressure of 0.3 MPa and a water rate of 100 L/min from spray nozzles at a height of 150 mm.
  • (a) shows the distribution of impact pressures in the case of use of oval nozzles A (spread angle: major axis direction 115 degrees/minor axis direction 60 degrees) and oblong nozzles B (spread angle: major axis direction 90 degrees/minor axis direction 25 degrees).
  • (b) shows the relationship between the water spray impact pressure and cooling rate in the case of cooling one side of thick-gauge steel plate of a plate thickness of 19 mm. Note that the measurement position is the center of plate thickness.
  • the present invention covers the cooling of thick-gauge steel plate having a temperature after hot rolling of 700 to 950° C. or so and a thickness of 3 to 150 mm or so and is mainly applied to the case of cooling thick-gauge steel plate by spraying the top surface side and bottom surface side of the thick-gauge steel plate with water from spray nozzles after finishing.
  • water means water, a mixture of water and air, or other cooling media.
  • the water sprays are prevented from striking the radial regions of the constraining rolls so as to suppress the uneven formation of interfering convection parts due to the plate top water on the thick-gauge steel plate, make the high cooling ability water sprays sufficiently reach the surface of the thick-gauge steel plate, stably secure the cooling efficiency, and realize stable cooling.
  • the water sprays are made to strike the bottom surface side of thick-gauge steel plate to balance the cooling ability between the top surface side and bottom surface side.
  • a cooling apparatus conveying high temperature thick-gauge steel plate constrained by a plurality of pairs of constraining rolls comprised of top rolls and bottom rolls and spraying the top and bottom surfaces of the thick-gauge steel plate with water to cool the thick-gauge steel plate
  • large numbers of spray nozzles are respectively arranged at the top surface side and bottom surface side of the thick-gauge steel plate so that the sum of the areas of the impact surfaces of the water sprays from the spray nozzles with the surface of the thick-gauge steel plate becomes within the range of 4 to 90% of the surface area of the steel plate at the distance (La) between the roll outer circumferences at the closest distance between pairs of constraining rolls at the top surface side and within the range of 4 to 100% at the bottom surface side.
  • a “spray impact part” is defined as a part where the impact pressure of the water spray is 2 kPa or more.
  • the impact pressure of the water spray has to be 2 kPa or more. If the impact pressure of the water spray is less than 2 kPa, the water spray cannot pass through the vapor film formed on the high temperature thick-gauge steel plate due to boiling and reach the steel plate and it is not possible to obtain a sufficient cooling ability.
  • the sum of the areas of the impact surfaces of the water sprays from the spray nozzles of the top surface side with the surface of the thick-gauge steel plate is less than 4% of the steel plate surface area in the distance (La) between the roll outer circumferences at the closest distance between the pairs of constraining rolls, the areas of the impact surfaces of the water sprays with the surface of the thick-gauge steel plate are not sufficient and a sufficient cooling ability cannot be secured.
  • the area rate of the impact surfaces is preferably 10% or more. Further, if the area rate of the impact surfaces is over 90%, interfering convection parts of water flows are unevenly formed and the high cooling ability water sprays are obstructed by the plate top water and will not strike the surface of the thick-gauge steel plate and as a result will not contribute sufficiently to the cooling. The flow of water discharged along the thick-gauge steel plate will increase, the cooling efficiency will drop, and the cooling will easily become uneven.
  • the area rate of the impact surfaces is 4 to 20%, the ratio of cooling by the plate top water becomes greater and the cooling ability drops somewhat. If changing the amounts of water to adjust the cooling ability, the change in cooling ability with respect to the amounts of water becomes no longer constant and adjustment of the cooling ability becomes somewhat difficult. However, the spray regions are small, so the power used is small and the cooling efficiency is excellent.
  • the area rate of the impact surfaces is 80 to 90%, the cooling ability becomes greater along with the increase in the impact areas, but the plate top water starts to pool and the uniformity of cooling in the width direction becomes somewhat inferior. Therefore, the area rate of the top surface side is more preferably 20 to 80%.
  • the area rate of the impact surfaces becomes 20% or more, it is possible to sufficiently agitate the regions where the plate top water is present by impacting sprays, so even when adjusting the amount of water, it is possible to determine the cooling ability in accordance with the change of the amount of water.
  • the sum of the areas of the impact surfaces of the water sprays from the bottom surface side spray nozzles with the surface of the thick-gauge steel plate is basically set so as to balance with the cooling ability of the top surface side, but if less than 4% of the steel plate surface area, the impact surfaces of the water sprays with the surface of the thick-gauge steel plate become insufficient and a sufficient cooling ability cannot be secured. As the area rate, 10% or more is desirable.
  • the cooling ability is improved together with the increase of the impact areas of the water sprays, so the impact area rate is preferably high. However, if over 95%, interference between sprays starts to occur and the uniformity of cooling falls, so 95% or more is preferable.
  • the impact areas may also be 100% (aspect of claim 1 ).
  • the spray nozzles are preferably arranged at the top surface side and bottom surface side of the thick-gauge steel plate so that the sum of the areas of the impact surfaces of the water sprays from the top surface side spray nozzles with the surface of the thick-gauge steel plate becomes 4 to 100% of the sum of the areas of the impact surfaces of the water sprays from the bottom surface side spray nozzles with the surface of the thick-gauge steel plate.
  • the sum of the areas of the impact surfaces of the water sprays from the spray nozzles with the surface of the thick-gauge steel plate can be made smaller than the sum of the areas of the impact surfaces of the water sprays from the bottom surface side spray nozzles with the surface of the thick-gauge steel plate so as to secure the balance of the cooling abilities at the top surface side and bottom surface side.
  • the impact areas of the top surface side are less than 30%, the region cooled by the plate top water at the top surface side becomes smaller than the bottom surface side, prediction of change of the cooling ability at the time of adjusting the amounts of water is difficult, the balance of the cooling abilities at the top and bottom surface sides becomes somewhat difficult to adjust.
  • the impact area rate of the top surface side is preferably 30 to 100% of the impact area rate of the bottom surface side.
  • Japanese Patent Publication (A) No. 2004-1082 discloses spraying so that the water spray impact parts on the surface of the thick-gauge steel plate occupy 60% or more of the steel plate area between the constraining rolls. This “60% or more” is outside the range of “4 to 90%” of the total area of the water spray impact parts with the thick-gauge steel plate area in the distance (La) between the roll outer circumferences at the closest distance between the pairs of constraining rolls defined at the top surface side in the present invention.
  • the distance (L) between the centers of the constraining rolls defined in Japanese Patent Publication (A) No. 2004-1082 is 1050 mm
  • the distance (La) between the outer circumferences at the closest distance between the pairs of constraining rolls defined in the present invention is 700 mm.
  • the “60% or more” in accordance with the definition of Japanese Patent Publication (A) No. 2004-1082 means 60% or more of the area of the thick-gauge steel plate in the 1050 mm region. If converted to the area of the thick-gauge steel plate in the 700 mm region of the present invention, this corresponds to “90% or more”. This is a condition where it is difficult to sufficiently achieve the object of the present invention.
  • the multihole columnar spray nozzles used at the top surface side are disadvantageous when increasing the impact areas of the water sprays, so are not used as the spray nozzles at the bottom surface side.
  • the bottom surface side spray nozzles are suitably selected for use from flat spray nozzles, oval spray nozzles, and oblong spray nozzles with a spread angle of the water spray of 0 to 100 degrees and full cone spray nozzles with a spread angle of the water spray of 0 to 40 degrees (see FIG. 5 ). Increasing the area of the impact surfaces of the water sprays with the surface of the thick-gauge steel plate is effective.
  • the spray nozzles used in the present invention may be a combination of a plurality of types of spray nozzles. It is not necessary to arrange the same types of spray nozzles correspondingly at the top and bottom surface side.
  • cooling after lowering the surface temperature of the thick-gauge steel plate is advantageous in that the boiling mode of the water at the time of cooling starts from the film boiling and transition boiling region.
  • thermal flux in scientific terms, referred to as the “thermal flux”
  • the thermal flux forms an N-shape
  • the surface temperature of the thick-gauge steel plate falls, and there is a temperature region where the cooling ability is improved. For this reason, reducing the surface temperature of the thick-gauge steel plate results in a higher cooling ability.
  • full cone spray nozzles and flat spray nozzles differ in impact areas even with the same water rates of the nozzles.
  • Flat spray nozzles can be designed with large water densities at the impact surfaces, so this is advantageous for the case of locally increasing the cooling ability.
  • spray nozzles and their arrangements are set in accordance with cooling conditions preset in accordance with the thick-gauge steel plate conditions, rolling conditions, and temperature/shape conditions sought in the rolling process, but are preferably set so as to enable control of the water density range in accordance with fluctuations in temperature of the thick-gauge steel plate and fluctuations in cooling temperature.
  • Two-fluid spray nozzles having structures enabling mixing and simultaneous spraying of water and air.
  • Two-fluid spray nozzles have a wide range of adjustment of amounts of water. Further, they are nozzles where adjustment of the impact forces of the water sprays is easy as well. Therefore, if employing two-fluid spray nozzles, the cooling control range can be broadened.
  • the pitch of arrangement in the case of arranging spray nozzles in the width direction of the thick-gauge steel sheet at the top and bottom surface sides differs depending on the type of the nozzles, but basically preferably, from the viewpoint of suppressing the number of nozzles to a minimum, is made a pitch of arrangement where the impact surfaces of the water sprays will not directly interfere with each other.
  • the spray nozzles are arranged separated so that the impact surfaces of the water sprays from the spray nozzles adjoining each other in the conveyance direction with the surface of the thick-gauge steel plate will not directly interfere.
  • the impact surfaces of the water sprays adjoining each other in the conveyance direction overlap by about 10 to 70% (equivalent) of the area of the impact surfaces in the width direction of the surface of the thick-gauge steel plate.
  • the spray nozzles When arranging the spray nozzles in the conveyance direction at the top surface side of the thick-gauge steel plate, it is preferable to arrange them as explained above so as to reliably ensure uniformity of water density in the thick-gauge steel plate width direction due to the spray nozzles in a unit of one set of constraining rolls in the rolling direction.
  • the above indicator of overlap differs from the area ratio (indicator) of the “sum of impact areas” with the surface area of steel plate in the distance between roll outer circumferences at the closest distance between pairs of constraining rolls.
  • the spray nozzles are arranged separated so that the impact surfaces of the water sprays from the spray nozzles adjoining each other with the surface of the thick-gauge steel plate will not directly interfere.
  • the spray nozzles may be arranged at both the width direction and conveyance direction of the thick-gauge steel plate so that the impact surfaces of the water sprays from the adjoining spray nozzles interfere.
  • the types (specifications), numbers, and mode of arrangements of the spray nozzles used at the top and bottom surface sides are selected in accordance with the size of the thick-gauge steel plate (thickness and width), temperature, and cooling target temperature. Further, the regions of arrangement of the spray nozzles at the bottom surface side are set considering the arrangement of spray nozzles at the top surface side and the regions on which plate top water acts so that the cooling ability becomes balanced. For example, the numbers of nozzles are not changed by the posture of the surfaces at the top surface side and bottom surface side and are determined by the types of selected nozzles and impact areas.
  • Example 1 of the thick-gauge steel plate cooling apparatus of the present invention will be explained based on FIGS. 1 to 4 .
  • FIG. 1 shows an example of arrangement of a thick-gauge steel plate production facility provided with the thick-gauge steel plate cooling apparatuses of the present invention.
  • a finishing mill 1 hot straightening device 3 , pairs of constraining rolls ( 5 1 , 5 2 ), and cooling apparatuses 4 comprised of top surface side cooling apparatuses 4 a and bottom surface side cooling apparatuses 4 b arranged between pairs of constraining rolls ( 5 1 , 5 2 ) are successively arranged in the conveyance direction.
  • a plurality of pairs of constraining rolls 5 1 , 5 2 are arranged in the conveyance direction and a plurality of top surface side cooling apparatuses 4 a and bottom surface side cooling apparatuses 4 b are arranged between said plurality of pairs in the conveyance direction, but here the explanation will be given of the top surface side cooling apparatus 4 a and bottom surface side cooling apparatus 4 b arranged between the pair of constraining rolls ( 5 1 , 5 2 ).
  • the top surface side cooling apparatus 4 a is arranged at the top surface side of thick-gauge steel plate 6 conveyed constrained between pairs of constraining rolls 5 1 , 5 2 , each comprised of a top roll 5 a and a bottom roll 5 b , arranged at the front and back of each other in the conveyance direction.
  • a plurality of full cone spray nozzles 7 are arranged separated in the width direction and conveyance direction of the thick-gauge steel plate 6 so that the impact surfaces of the water sprays 7 a do not interfere.
  • four lines of nozzles 7 1 , 7 2 , 7 3 , and 7 4 are arranged in the conveyance direction of the thick-gauge steel plate 6 .
  • the lines of nozzle are arranged so that the impact surfaces of the water sprays 7 a of the full cone spray nozzles 7 of the lines of nozzles adjoining in the conveyance direction, for example, the lines of nozzles 7 1 and 7 2 , form overlap parts d of about 30% of the areas of the impact surfaces in the width direction of the surface of the thick-gauge steel plate 6 .
  • Each full cone spray nozzle 7 used for the top surface side cooling apparatus 4 a has a conical shape of water spray 7 a , a circular impact surface with the surface of the thick-gauge steel plate 6 , and a spread angle ⁇ of the water spray 7 a of 35 degrees.
  • the full cone spray nozzles 7 forming the lines of nozzles 7 1 to 7 4 are arranged so that the sum So of the areas of the impact surfaces of the water sprays 7 a of the full cone spray nozzles 7 becomes 40% of the area S of the thick-gauge steel plate (La ⁇ thick-gauge steel plate width w) at the distance (La) between roll outer circumferences at the closest distance of the pairs of constraining rolls 5 1 , 5 2 .
  • the bottom surface side cooling apparatus 4 b is arranged so as to face the top surface side cooling apparatus 4 a across the thick-gauge steel plate 6 .
  • a plurality of full cone spray nozzles 8 are arranged separated in the width direction of the thick-gauge steel plate 6 so that the impact surfaces of the water sprays 8 a do not interfere.
  • four lines of nozzles 8 1 to 8 4 are arranged in the conveyance direction of the thick-gauge steel plate 6 .
  • the lines of nozzle are arranged so that the impact surfaces of the water sprays 8 a of the full cone spray nozzles 8 of the lines of nozzles adjoining in the conveyance direction, for example, the lines of nozzles 8 1 and 8 2 , form overlap parts d of about 40% of the areas of the impact surfaces in the width direction of the surface of the thick-gauge steel plate 6 .
  • Each full cone spray nozzle 8 used for the bottom surface side cooling apparatus 4 b has a conical shape of water spray 8 a , a circular impact surface with the surface of the thick-gauge steel plate 6 , and a spread angle ⁇ of the water spray 8 a of 40 degrees and therefore differs somewhat from the full cone spray nozzle 7 used for the top surface side cooling apparatus 4 a.
  • the full cone spray nozzles 8 forming the lines of nozzles 8 1 to 8 4 are arranged so that the sum Su of the areas of the impact surfaces of the water sprays 8 a of the full cone spray nozzles 8 becomes 50% of the area S of the thick-gauge steel plate (La ⁇ thick-gauge steel plate width w) at the distance (La) between roll outer circumferences at the closest distance of the pairs of constraining rolls 5 1 , 5 2 .
  • the full cone spray nozzles 7 forming the lines of nozzles 7 1 to 7 4 are arranged so that the sum So of the areas of the impact surfaces of the water sprays 7 a of the full cone spray nozzles 7 becomes 80% of the sum Su of the areas of the impact surfaces of the water sprays 8 a of the full cone spray nozzles 8 forming the lines of nozzles 8 1 to 8 4 at the bottom surface side cooling apparatus 4 b.
  • Example 2 of the thick-gauge steel plate cooling apparatus of the present invention will be explained based on FIGS. 6( a ) to 6 ( c ).
  • Example 2 like Example 1, has full cone nozzles 7 arranged at the top surface side cooling apparatus 4 a as shown in FIGS. 6( a ) and 6 ( b ).
  • the full cone nozzles 7 are arranged so that the sum So of the areas of the impact surfaces of the water sprays 7 a of the full cone spray nozzles 7 with the thick-gauge steel plate becomes 40% of the area S of the thick-gauge steel plate at the distance (La) between roll outer circumferences at the closest distance of the pairs of constraining rolls 5 1 , 5 2 .
  • the bottom surface side cooling apparatus 4 b is arranged so as to face the top surface side cooling apparatus 4 a across the thick-gauge steel plate 6 .
  • Oblong spray nozzles 9 are arranged with their major axis directions slanted with respect to the conveyance direction and separated so that the impact surfaces of the adjoining water sprays 9 a with the thick-gauge steel plate 6 do not interfere.
  • four lines of nozzles 9 1 , 9 2 , 9 3 , and 9 4 comprised of pluralities of oblong spray nozzles are arranged in the conveyance direction of the thick-gauge steel plate 6 . Between the lines of nozzles, as shown in FIGS.
  • the lines of nozzles are arranged so that the impact surfaces of the water sprays 9 a of the oblong spray nozzles 9 of the lines of nozzles adjoining in the conveyance direction, for example, the lines of nozzles 9 1 and 9 2 , form overlap parts d of about 50% of the areas of the impact surfaces in the width direction of the surface of the thick-gauge steel plate 6 .
  • Each oblong spray nozzle 9 used in the bottom surface side cooling apparatus 4 b has a substantially fan shape of water spray 9 a , an oblong impact surface with the surface of the thick-gauge steel plate 6 , a spread angle ⁇ of the major axis side of the water spray 9 a of 80 degrees, and a spread angle ( ⁇ ) of the minor axis side of the water spray 9 a of 20 degrees.
  • the oblong spray nozzles 9 of the lines of nozzles 9 1 to 9 4 are arranged so that the sum Su of the areas of the impact surfaces of the water sprays 9 a of the oblong spray nozzles 9 becomes 80% of the area S of the thick-gauge steel plate at the distance (La) between roll outer circumferences at the closest distance of the pairs of constraining rolls 5 1 , 5 2 .
  • the area So of the impact surfaces of the water sprays 7 a of the full cone spray nozzles 7 with the thick-gauge steel plate 6 becomes 50% of the area Su of the impact surfaces of the water sprays 9 a from the oblong spray nozzles 9 of the bottom surface side cooling apparatus 4 b.
  • Example 3 of the thick-gauge steel plate cooling apparatus of the present invention will be explained based on FIGS. 7 A( a ) and 7 A( b ) and FIGS. 7 B( a ) and 7 B( b ).
  • Example 3 like Example 1 and Example 2, has the top surface side cooling apparatus 4 a arranged as shown in FIG. 7 A( a ) and has oval spray nozzles 10 shown in FIG. 5( c ) arranged as shown in FIG. 7 B( a ) with their major axis directions parallel to the width direction of the thick-gauge steel plate 6 and separated so that impact surfaces of the water sprays 10 a from the oval spray nozzles 10 adjoining each other in the conveyance direction and width direction of the thick-gauge steel plate 6 do not interfere.
  • four lines of nozzles 10 1 , 10 2 , 10 3 , and 10 4 comprised of pluralities of oval spray nozzles are arranged in the conveyance direction of the thick-gauge steel plate 6 .
  • the lines of nozzles are arranged so that the impact surfaces of the water sprays 10 a of the oval spray nozzles 10 of the lines of nozzles adjoining in the conveyance direction, for example, the lines of nozzles 10 1 and 10 2 , form overlap parts d of about 40% of the areas of the impact surfaces in the width direction of the surface of the thick-gauge steel plate 6 .
  • each oval nozzle 10 used in the top surface side cooling apparatus 4 a has a substantially fan shape of water spray 10 a , an oval impact surface with the surface of the thick-gauge steel plate 6 , a spread angle ⁇ of the major axis side of the water spray 10 a of 70 degrees, and a spread angle ⁇ of the minor axis side of the water spray 10 a of 30 degrees.
  • the oval spray nozzles 10 are arranged so that the sum So of the areas of the impact surfaces of the water sprays 10 a from the oval nozzles 10 of the lines of nozzles 10 1 to 10 4 becomes 80% of the area S of the thick-gauge steel plate 6 in the distance (La) between roll outer circumferences at the closest distance of the pairs of constraining rolls 5 1 , 5 2 .
  • the bottom surface side cooling apparatus 4 b is arranged at the bottom surface side of thick-gauge steel plate so as to face the top surface side cooling apparatus 4 a across the thick-gauge steel plate 6 .
  • the oval spray nozzles 10 are arranged with their major axis directions parallel to the width direction of the thick-gauge steel plate 6 and to allow impact surfaces of the water sprays 10 a to interfere in the width direction and conveyance direction of the thick-gauge steel plate 6 .
  • four lines of nozzles 10 1 , 10 2 , 10 3 , and 10 4 comprised of pluralities of oval nozzles are arranged in the conveyance direction of the thick-gauge steel plate 6 . Between the lines of nozzles, as shown in FIG. 7 A( b ) and FIG.
  • the lines of nozzles are arranged so that the impact surfaces of the water sprays 10 a of the oval spray nozzles 10 of the lines of nozzles adjoining in the conveyance direction, for example, the lines of nozzles 10 1 and 10 2 , form overlap parts d of about 40% of the areas of the impact surfaces in the width direction of the surface of the thick-gauge steel plate 6 .
  • Each oval spray nozzle 10 used in the bottom surface side cooling apparatus 4 a has a substantially fan shape of water spray 10 a , an oval impact surface with the surface of the thick-gauge steel plate 6 , a spread angle ⁇ of the major axis side of the water spray 10 a of 70 degrees, and a spread angle ⁇ of the minor axis side of the water spray 10 a of 30 degrees.
  • the oval spray nozzles 10 of the lines of nozzles 10 1 to 10 4 are arranged so that the sum Su of the areas of the impact surfaces of the water sprays 10 a from the oval spray nozzles 10 becomes 100% of the area S of the thick-gauge steel plate 6 in the distance (La) between roll outer circumferences at the closest distance of the pairs of constraining rolls 5 1 , 5 2 .
  • the oval spray nozzles 10 are arranged so that the area So of the impact surfaces of the water sprays 10 a from the oval spray nozzles 10 with the thick-gauge steel plate 6 becomes 90% of the area Su of the impact surfaces of the water sprays 9 a from the oval spray nozzles 10 of the bottom side cooling apparatus 4 b with the thick-gauge steel plate 6 .
  • Example 1 the full cone spray nozzles shown in FIG. 5( a ), oval spray nozzles FIG. 5( c ), and oblong spray nozzles shown in FIG. 5( d ) were used, but in the present invention, the flat spray nozzles shown in FIG. 5( b ), the multihole columnar spray nozzles 16 shown in FIG. 5( e ) (water spray shape 16 a ), and other spray nozzles able to be sufficiently controlled in spray pressure and spray rate (water density) can be suitably selected for use.
  • FIG. 8 it is also possible to use for example flat spray nozzles 15 having the water spray shapes 15 a shown in FIG. 5( b ) and the full cone spray nozzles 7 having the water spray shapes 7 a shown in FIG. 5( a ) in combination.
  • the types of spray nozzles arranged at the top surface side cooling apparatus 4 a and bottom surface side cooling apparatus 4 b , the nozzle specifications, the number of nozzles, the arrangement conditions, the combination conditions, and the ratio So/S, Su/S, and So/Su of the area of the impact surfaces of the water sprays with respect to the surface area of the thick-gauge steel plate 6 were changed to run cooling experiments on the thick-gauge steel plate.
  • the comparative examples are examples which satisfy parts of the ranges defined by the present invention, but do not satisfy all of the ranges.
  • the experimental conditions are as explained below.
  • the experimental conditions of the comparative examples are made the same as the experimental examples of the present invention.
  • the uniformity of temperature of the thick-gauge steel plate in the width direction is shown by the average value of the temperature difference of the top and bottom surfaces of the thick-gauge steel plate 6 in the width direction in the region of the thick-gauge steel plate 6 right after cooling excluding 1 meter at the front and tail ends in the conveyance direction and further excluding 100 mm at the two ends in the width direction.
  • the width uniformity target temperature was set to 30° C.
  • the uniformity of temperature of the thick-gauge steel plate in the plate thickness direction is shown by the average value of the temperature difference of the top and bottom surfaces of the thick-gauge steel plate 6 at the center of the width direction right after cooling (top surface temperature-bottom surface temperature).
  • top/bottom uniformity target temperature was set to 20° C.
  • the difference from the cooling target temperature is shown by the difference between the average value of the temperature of the top surface of the thick-gauge steel plate 6 at the center of the width direction right after cooling and the cooling target temperature (resultant temperature-target temperature).
  • a negative value shows a low cooling ability and a positive value shows a high cooling ability.
  • the average temperature of the cooled thick-gauge steel plate 6 (average value of the temperatures at the centers of the width direction at the top and bottom surfaces) was within the range of ⁇ 30° C. of the cooling target temperature and sufficiently satisfactory cooling could be realized.
  • Comparative Examples 1 to 8 satisfying part of the conditions of the present invention but not satisfying all (claims 1 , 2 ) of the conditions, it was not possible to satisfy one or both of the evaluation indicators of (i) and (ii) and it was not possible to obtain thick-gauge steel plate 6 superior in uniformity able to satisfy both the requirements of shape and quality.
  • the present invention is not limited to the conditions employed in the above examples.
  • the numbers of top surface side spray nozzles and bottom surface side spray nozzles arranged in the conveyance direction, the types (structures) and specifications of the spray nozzles, the arrangement conditions (numbers and lines), conditions of the water sprayed from the lines of nozzles, size and arrangement conditions of the constraining rolls, etc. can be suitably changed within the scope defined by the claims in accordance with the size of the thick-gauge steel plate being cooled (in particular, the thickness), temperature, conveyance speed, target cooling temperature, cooling time, cooling rate, etc.
  • the flatness of thick-gauge steel plate can be improved, so cold straightening and finishing costs can be reduced. Further, the residual stress can also be reduced and the deformation at the time of working the steel plate can be suppressed and the work precision can be easily stably secured. Further, securing uniformity of quality also becomes easy.
  • the present invention has great applicability in the ferrous metal industry.

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  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Metal Rolling (AREA)
US11/922,715 2005-06-23 2005-12-22 Cooling Apparatus of Thick-Gauge Steel Plate Abandoned US20090108509A1 (en)

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US20150101386A1 (en) * 2012-06-08 2015-04-16 Nippon Steel & Sumitomo Metal Corporation Water-blocking apparatus and water-blocking method for cooling water for hot-rolled steel sheet
US9649679B2 (en) * 2012-06-08 2017-05-16 Nippon Steel Sumitomo Metal Corporation Water-blocking apparatus and water-blocking method for cooling water for hot-rolled steel sheet
US9833822B2 (en) 2012-12-25 2017-12-05 Jfe Steel Corporation Method and apparatus for cooling hot-rolled steel strip
CN105392574A (zh) * 2013-07-03 2016-03-09 蒂森克虏伯钢铁欧洲股份公司 用于热轧带钢的装置及方法
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CN111826505A (zh) * 2020-06-24 2020-10-27 中航工程集成设备有限公司 一种铝合金中厚板多级淬火冷却喷淋系统及实施方法

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EP1908535A4 (en) 2008-08-06
WO2006137187A1 (ja) 2006-12-28
BRPI0519986A2 (pt) 2009-04-07
CN101247902A (zh) 2008-08-20
EP1908535A1 (en) 2008-04-09
BRPI0519986B1 (pt) 2019-06-04
CN101247902B (zh) 2010-11-24
IN2014MN01155A (pt) 2015-07-03
EP1908535B1 (en) 2012-10-31
KR100935490B1 (ko) 2010-01-06
KR20080010463A (ko) 2008-01-30
RU2383402C2 (ru) 2010-03-10
US9085810B2 (en) 2015-07-21
RU2008114905A (ru) 2009-10-27

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