US3897906A

US3897906A - Cooling device for strands that are to be cast continuously

Info

Publication number: US3897906A
Application number: US489358A
Authority: US
Inventors: Ernst Bachner
Original assignee: Voestalpine AG
Current assignee: Voestalpine AG
Priority date: 1973-07-27
Filing date: 1974-07-17
Publication date: 1975-08-05
Anticipated expiration: 1992-08-05
Also published as: FR2238550B1; BE817309A; SE7407358L; GB1481220A; ES427725A1; BR7406183D0; JPS5328129B2; DE2435495A1; FR2238550A1; SE409960B; IT1016221B; CH573780A5; DE2435495C2; CA1018348A; JPS5039631A; AT323921B

Abstract

The invention relates to a cooling device for strands that are to be cast continuously, in particular for steel slabs of different widths. Spray nozzles connected to pipe conduits for supplying a coolant are distributed over the width and the length of the strand. The hitherto known cooling devices used in continuous casting have the disadvantage that the cooling effect becomes irregular when the slab size is changed. This disadvantage is eliminated by the device of the invention by arranging the spray nozzles horizontally displaceable transverse in relation to the strand surface.

Description

1 Aug. 5, 1975 United States Patent [191 Bachner Uni/283 i 1 COOLING DEVICE FOR STRANDS THAT IHUUESS M1974 Bushkm ct Lll.

ARE TO BE CAST CONTINUOUSLY [75] Inventor: Ernst Bachner. Linz, Austri Primary L.\tllllill&'l'RUhCft S. Ward Jr.

.ixrismm h',\ulnim'rMichael Mur Assigncc:

\"ereinigte Osterreichische Eisen- .'iII(II'H( Again. or Finn-Brumbuugh, Graves, Donohuc & Raymond [22] Filed1 1211 Appl. No: 489.358

The invention relates to u cooling dcvicc for strands that are to be cast continuously. in particular for steel slabs of different widths. Spray nozzles connected to Foreign Application Priority Data 1 1 r v (wk/7' pipe conduits for supplying u cool-tint are distributed over the width und the length of the strand. The hithcrtu known cooling devices used in continuous casting 2 H 1 al Md .1 7- 7.. 88 l 93 3 C L n have the disadvuntagc that the cooling effect becomes irregular when thc slah size is changed. This disadvanh C r. a e

we 4 5 U! 3 2 tuge is eliminated b the device of the invention by ur- 3.499.456 Rcrccich ct :il. Hui/Z33 S X 5 Claims. 2 Drawing Figures COOLING DEVICE FOR STRANDS THAT ARE TO BE CAST CONTINUOUSLY The invention relates to a cooling device for strands that are to be cast continuously, in particular for steel slabs of different widths, with spray nozzles distributed over the width and length of the strand. which nozzles are connected to pipe conduits for the supply with the cooling medium.

Known cooling devices for continuous casting plants. as they are described in the Austrian Pat. Specifications Nos. 233,l86 and 265.550 comprise a stationary system of spray nozzles for water or mixtures of water and a gaseous medium. e.g. compressed air, which nozzles are directed towards the strand surface and are con nected to pipe conduits. The spray nozzles are arranged between the support rollers, respectively the guiding rollers for the strand. In order to achieve a uniform cooling of the strand, spray nozzles with a flat characteristic and a staggered arrangement of the nozzles, seen in transport direction of the strand, have been proposed; moreover it has been known to supply the spray nozzles groupwisely with a cooling agent, wherein the capacity of the cooling agent of the one group selectively alternates, cyclically with the altered capacity of the cooling agent of another group. Finally it has also been recommended to provide individual rows of spray nozzles to be completely separately capable of being regulated or turned off, respectively, in particular the nozzles lying in the range of the edges of the strand, so that the strand edges be not cooled too strongly, which leads to the formation of cracks. The turning off of individual spray nozzles has the disadvantage that, when the nozzles remain turned off for a longer period. im purities of the cooling agent are deposited in the pipe conduits, which may lead to a choking of the nozzle bores, when the nozzles are turned on again.

All known cooling devices used in continuous casting have the disadvantage that the cooling effect becomes varied and irregular, when the slab sizes are changed; because with certain sizes it is inevitable that the strand edges come to lie in the range of the fixedly mounted spray nozzles and are cooled too strongly with width fluctuations occurring in practice that lie between approx. 800 mm and up to approx. 2,500 mm the strand edges may get into the middle range of the cooling device, where a selective cooling is not possible. This means that, when the width of the strand is changed, complicated technical installations, which are liable to disturbances, become necessary, because with a large number of spray nozzles one has to operate with extremely small nozzle bores, which tend to become choked easily.

It is the object of the invention to avoid these difficulties and to provide an operationally reliable, simple cooling device for strands of different widths, wherein the number of spray nozzles can be reduced and the diameter of their bores can be enlarged.

In a cooling device of the above described type this problem is solved by arranging the spray nozzles transverse in relation to the strand surface capable of being displaced horizontally.

A preferred embodiment consists in that the spray nozzles can be moved oscillating within two limit lines, which can be adjusted in a freely selectable distance from the strand edges.

Suitably at least two spray nozzles per strand side are arranged displaceably side by side in a plane perpendicular to the strand surface, wherein their displacement range is smaller than half the strand width.

Furthermore the spray nozzles can be moved towards each other or away from each other mirror-symmetrically in relation to the strand center.

A development of the invention consists in that the spray nozzles seen in transport direction of the strand are arranged staggered in a manner known per se and are combined in groups, wherein the degree of staggered arrangement advantageously corresponds to the displacement range.

The invention will now be described in more detail by way of example with reference to the accompanying drawings.

FIG. I shows a side view ofa continuous casting plant for slabs, illustrated schematically.

FIG. 2 is a view of the width of the slab below the mold, wherein for reasons of better clarity the supportand guiding rollers are not shown.

In FIG. I, 1 denotes a water-cooled. vertically oscillating mold, from which a strand 2 is withdrawn. The rollers for supporting, guiding and bending the strand 2 from the vertical to the horizontal are denoted with 3 and the driven withdrawing rollers are denoted with 4; the withdrawal direction is indicated by the arrow 5. The cooling device arranged to follow the mold I, the so-called secondary cooling zone, comprises three sec tions 6, 7 and 8, formed by the cooling-water pipes 9, l 1, l2 and the spray nozzles 10. The spray nozzles 10 are arranged between the rollers 3 in all three cooling sections. According to the invention the spray nozzles are, groupwise together with the pertaining coolingwater-supply pipes 9, II, 12, horizontally displaceable, transversely to the strand surface, as can be seen in detail from FIG. 2.

Each section 6, 7, 8 of the cooling system is provided with two spray nozzle rows per strand side, which spray nozzles are parallel in relation to the strand center 20 and are fixedly connected with the pipes 9, I], 12. Perpendicularly to the pipes 9, I I, 12, further pipes I3, l4, 15 are connected, which are horizontally displaceable in sliding bearings I6, so that the pipes 9, II, 12 oscillate between the limit lines 17, [8 about the range a. As drive means for the pipes various installations known to the man skilled in the art may be used, as e.g. hydraulically or pneumatically operable, doubly actuated pistons, spindles with an electromotoric drive motor, capable of altering the direction of rotation, crank rods, etc, wherein the movement backward and forward in the direction of the double arrows in uniform, e.g, sinusoidal or irregular in such a way that eg. the rest period of the spray nozzles 10 in the range of the strand center 20 or in the range of the limit lines 17 adjacent thereto, respectively, is bigger than in the range of the strand edges 19 or in the range of the limit lines 18, adjacent thereto, respectively. In FIG. 2 the pipes 9, I2 are arranged staggered in relation to the pipes 11, so that by displacement into the positions 9'. II. I2, a plurality of screwshaped lines results, which represent the geometrical locus of the points of impact of the water jets on the moved strand surface. By balancing the strandwithdrawal-speed and the oscillation of the spray nozzles 10 in connection with the amount of cooling water and the angle of opening of the spray nozzles (the spray characteristic) a uniform cooling of the strand 2 can easily be achieved. When the strand width is changed only the position of the limit lines I8 and the oscillation stroke a have to be newly stipulated, which can, in the case of an electromotoric drive, be carried out by adjusting the limit switch. The distance b of the limit lines 18 from the strand edges 19 is fixed corresponding to the opening angle of the spray nozzles, so that a subcooling of the strand is avoided. The distance between the limit lines 17 also depends on the spray characteristic of the nozzles used, i.e. it is to be chosen in such a way that also the middle zone is completely actuated by the coolant, when the spray nozzles are in one final position 9, ll, 12.

Of course different embodiments and variations of the invention are possible. The number of spray nozzles forming a group 6, 7, 8 may fluctuate between i and n, preferably between 2 and n; with narrow slabs one can do with one single spray nozzle oscillating forward and backward between the lines 18 in a plane between the rollers 3 and with wide slabs two spray nozzles 10 in a plane are sufficient, which are then arranged, as illustrated in FIG. 2, and are moved in opposite direction relative to each other. Also the number of spray nozzles 10 of a group arranged one following the other in the direction of the movement 5 of the strand 2 may vary between 1 and n. Each group can therefore comprise a different number of nozzles; it is however important that the spray nozzles be arranged mirror-symmetrically in relation to the strand center and that the horizontal movement of the pipes l3, l4, l5 correspond in one and the same plane on both halves of the strand. lf as shown in this embodiment only two nozzles 10 each are used between the rollers 3, the nozzles can have a correspondingly big exit cross section which can hardly be choked by impurities contained in the coolant; the operational reliability of the device is thus decreased and much less maintenance of the secondary cooling zone is necessary, because in the coolant system there is no need for complicated control and regulating devices.

What I claim is:

l. in a cooling device for strands that are to be cast continuously, in particular for flat steel slabs of different widths, said strands having edges and a pair of parallel flat surfaces, said cooling device comprising a plurality of spray nozzles distributed over the width and along a given length of the strand, the spray nozzles being connected to pipe conduits for supplying them with a coolant, the improvement in which the spray nozzles are movable along horizontal straight line paths within a displacement range less than the width of said strand, said paths being transverse to the strand surface.

2. ln a cooling device for strands that are to be cast continuously, in particular for steel slabs of different widths, said strands having edges and a surface. said cooling device including a plurality of spray nozzles distributed over the width and along a given length of the strand, the spray nozzles being connected to pipe conduits for supplying them with a coolant, the improvement in which, said spray nozzles are movable horizontally and transverse to the strand surface in an oscillatory manner between two limit lines, the limit lines being adjustable within a freely selectable distance from the edges of the strand.

3. In a cooling device for strands that are to be cast continuously, in particular for steel slabs of different widths, said strands having edges and a surface, said cooling device including a plurality of spray nozzles distributed over the width and along a given length of the strand, the spray nozzles being connected to pipe conduits for supplying them with a coolant, the improvement in which, there are at least two spray nozzles on each side of the strand arranged side by side and in a plane perpendicular to the surface of the strand, and said nozzles are movable horizontally and transverse to the strand within a displacement range smaller than half the width of the strand.

4. In a cooling device for strands that are to be cast continuously, in particular for steel slabs of different widths, said strands having edges and a surface, said cooling device including a plurality of spray nozzles distributed over the width and along a given length of the strand, the spray nozzles being connected to pipe conduits for supplying them with a coolant, the improvement in which, said spray nozzles are movable towards and away from each other, horizontally and transverse to the strand, in mirror-symmetry with respect to the center of the strand.

5. In a cooling device for strands that are to be cast continuously, in particular for steel slabs of different widths, said strands having edges and a surface, said cooling device including a plurality of spray nozzles distributed over the width and along a given length of the strand, the spray nozzles being connected to pipe conduits for supplying them with a coolant, the improvement in which, said spray nozzles are movable horizontally and transverse to the strand within a certain displacement range and are arranged in groups along the direction of movement of the strand, the nozzles of one group being staggered in position relative to the center of the strand with respect to the nozzles of adjacent groups by a distance substantially equal to said displacement range.

l i 1k UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,897,906

DATED Aug. 5, 1975 INVENTOR(S) Ernst Bachner It is certified that error appears in the above-identified patent and that satd Letters Patent are hereby corrected as shown below:

Col. 1, line 42, "strongly with" should read strongly.

With--; and

Col. 3, line 35, "decreased" should read increased-.

Signed and Scaled this seventh Day of 0cto'b-erI975 [SEAL] Arrest:

RUTH C. MASON Arresting Officer C. MARSHALL DANN ('nmmissirmer of Parents and Trademarks

Claims

1. In a cooling device for strands that are to be cast continuously, in particular for flat steel slabs of different widths, said strands having edges and a pair of parallel flat surfaces, said cooling device comprising a plurality of spray nozzles distributed over the width and along a given length of the strand, the spray nozzles being connected to pipe conduits for supplying them with a coolant, the improvement in which the spray nozzles are movable along horizontal straight line paths within a displacement range less than the width of said strand, said paths being transverse to the strand surface.

2. In a cooling device for strands that are to be cast continuously, in particular for steel slabs of different widths, said strands having edges and a surface, said cooling device including a plurality of spray nozzles distributed over the width and along a given length of the strand, the spray nozzles being connected to pipe conduits for supplying them with a coolant, the improvement in which, said spray nozzles are movable horizontally and transverse to the strand surface in an oscillatory manner between two limit lines, the limit lines being adjustable within a freely selectable distance from the edges of the strand.