US3176355A

US3176355A - Method and an apparatus for regulating the cooling of continuous casting material inthe secondary cooling zone

Info

Publication number: US3176355A
Application number: US203522A
Authority: US
Inventors: Ljungstromer Lars-Einar
Original assignee: Concast AG
Current assignee: SMS Concast AG
Priority date: 1961-06-19
Filing date: 1962-06-19
Publication date: 1965-04-06
Anticipated expiration: 1982-04-06
Also published as: FR1325482A

Description

April 6, 1965 LARS-EINAR LJUNGSTROMER 3,176,355

METHOD AND AN APPARATUS FOR REGULATING THE COOLING OF CONTINUOUS CASTING MATERIAL- IN THE SECONDARY COOLING ZONE Filed June 19, 1962 5 6. .9 a. 1 m Hm n 3 I. \v H .m. F \v M \2 .1 I I 1 G b C d 9 f 0 .D C d 9 f 2 M B .I. 0 .11, 1 .a I 1 9 1 7 PM T v 1 1111 .1 11 1 1 1 Q a 1% y w a k 1 11 11 1T111h1 .11 7 w B I a 2 1 1 171 influencing the mentioned values.

United States Patent 3 176 355 METHOD AND AN AlPAiRATUS non REGULAT- ING THE COOLING OF CGNTINUQUS CASTHNG MATEL IN THE SECONDARY COOLING ZONE Lars-Einar Ljungstromer, Torshalla, Sweden, assignor to Concast AG., Zurich, witzerland Filed June 19, 1%2, Ser. No. 2%,522 Claims priority, application S/witzerland, June 19, 1961,

61 5 Claims. c1. 22-s7.2

This invention relates to continuous casting and, more particularly, relates to an improved method and apparatus for secondary cooling of the strand issuing from a continuous casting mold.

In this art of continuous casting a supply of molten metal is continuously fed to one end of a mold cavity of suitable cross-section, the walls of which in contact with the poured metal are cooled by a circulating fluid in contact with the outside of the mould wall in a primary cooling zone that will cause rapid solidification of metal in contact with the mould walls.

The cast metal, commonly referred to as a strand, having a uniform cross-section corresponding to that of the mould cavity throughout its length, is withdrawn by an appropriate withdrawal mechanism from the opposite end of the mold in continuous manner during the entire process and is then directly cooled in a secondary cooling zone. The present invention relates more particularly to a method and to an apparatus for regulating this secondary cooling that is eliected by spraying cooling fluid against the ingot through nozzles arranged in a plurality of planes.

Such a secondary cooling zone with the associated guiding for the ingot is described in more detail in the US. Patent No. 2,284,503 Apparatus for continuous casting of Edward R. Williams. Accurate control of the cooling in this secondary cooling zone is of outstanding importance for the quality of the product, i.e. of the produced strand. In order to obtain an optimum cooling effect the strand is cooled by water atomized by means of special nozzles. Therefore the position of the nozzles with respect to the strand surface, the dimension and the spraying angles as Well as also the water pressure are variable values which may have a decisive influence upon the quality of the cast ingot.

There are several methods and apparatus known for For example in a known method, the nozzles are arranged in such manner that the atomized cooling fluid is directed only against the plane surfaces of the ingot while the edges of the latter undergo practically no cooling.

A further publication describes a method in which the cooling varies along the periphery of the ingot. This is obtained by a periodical arrangement of the spraying nozzles at different levels. This publication also indicates the possibility of arranging spraying rings whereby the cooling effect may be modified at the circumference of the ingot by appropriate shielding. Spraying rings have the drawback that with them the distance of the spraying nozzles from the ingot surface cannot be modified. It is also known to vary the borings of the spraying rings with respect to their dimension, distance and positioning.

In a further publication it is suggested to arrange spraying nozzles at rings in groups or separately at increasing distances from the mould.

The spraying rings are generally fed with cooling fluid through feeding conduits, whereby either each spraying ring or a group of spraying rings is provided with a I respective feeding conduit. In the first case limited modifications of the cooling effect may be obtained by closing or adjusting valves, such regulations by means of valves having the drawback that not only the volume of the cooling fluid but simultaneously also the spraying angle, the degree of atomization, the characteristics of the distribution etc., are modified which may lead to the formation of cracks in the ingot. Moreover if billets shall be produced it is generally not possible to provide separate feeding conduits for the spraying rings due to lack of space. Also such separate feeding conduits are mounted on the exchangeable roller bed so that corresponding flexible connections are required. In the second case mentioned above, i.e. when one feeding conduit supplies several spraying rings which of course results in a simpler construction the possibility of regulating the cooling is accordingly very limited.

None of the mentioned known systems renders possible a very general regulation of the cooling without modification of the arrangement of the cooling apparatus. Now if it is desired to use one mould of a particular shape for casting different qualities of steel, which as is well known require diiferent cooling, or if the casting speed must be adjusted to meet particular requirements it should be possible to adapt the cooling in the secondary cooling zone to the quality of steel that is to be casted or to the casting speed that will be used, which in the known systems and more particularly in the system using spraying rings leads to time-wasting disassembling and assembling operations.

It is a primary object of the present invention to provide for means permitting the production of continuous casting products of different qualities and more particularly the production of strands with the same cooling apparatus.

In accordance with the present invention this aim is attained by a method for regulating the cooling of continuous casting material in the secondary cooling zone, by spraying cooling fluid onto it through spraying nozzles arranged in several planes, in which cooling fluid is supplied through feeding conduits to one or several groups of nozzles in accordance with the cooling requirements, whereby each of said groups of nozzles comprising at least one nozzle from at least two planes of a device comprising a plurality of nozzles in each of several planes, the sequence of the nozzles of one group being cyclically interrupted by nozzles of at least one other group.

A further object of the present invention is to provide apparatus for carrying out the above method in which apparatus at least one nozzle arranged in one of said planes is combined with at least one nozzle in another of said planes to form one of said groups, the nozzles of each group being connected with a common feeding conduit for cooling fluid, the sequence of the nozzles being cyclically interrupted by nozzles of at least another group and the passage of cooling fluid through each of such feeding conduits being controllable separately.

Other features and advantages of the present invention will appear from the description, now to follow, of preferred embodiments thereof, given by way of example only, and in which reference will be made to the accompanying drawings, in which:

FIGURE 1 is a cross-section through a billet and through a square nozzle block along the line I-l of FIGURE 2.

FIGURE 2 is a view of the nozzle block of FIG- URE 1.

FIGURE 3 is a cross-section through a nozzle block having concentrically arranged feeding pipes.

FIGURE 4 is a cross-section through a slab with a nozzle block associated thereto, and

FIGURES 5 and 6 illustrate examples of different cooling fluidfwhich preferably is water.

ings that'may' be obtained in accordance with the present invention. I

Referring nowto the drawings and more particularly to FIGURES l and 2 thereof, reference numeral-'1 designates a strand passing the secondary cooling vzone of a continuous casting plant. "Nozzles 2 to 10, of'the type shown'for example in 'the1U;.S. Patent 2,621,078,

arranged parallel to the axis of this strand, spray cool-I ing fluid against each longitudinal side;of the strand For the sake of simplicity the spraying isjshown for one side only 'of the strand and also the guiding ofthe strand is not shown.- Thenozzles'2 to 10 are-screwed into a square nozzle block 11 into the side thereof facing theslab. To

. a t a a to f'perpendicular to the axis of the slabinto the following cyclic sequence of the nozzle action:

[I v n 1111 IV v v1 VII Both nozzle blocks Ifand VII arranged on thenarrow "side of the slab together, comprise 12 and the nozzle the other side of the nozzle block 11

feeding conduits

12, 13 andt14 having the shapeof semicircular pipes 115 are welded and these feeding conduits are fed with cool- The nozzles 2 to, 14 are'connected to the feeding conduits through cor-l ings and this connection is ettected'in cycled circuits, In

other words and referring ;tothe** shown example, the nozzles 2 and 5 and 8,, respectively, are' connected by

borings

15 and 18 and 21, respectively, with the feecling conduit 12, the nozzles 3 and '6 and 9, respectively,

are connected by the

borings

16 and 19 and 22,"respec-,.

tively, with the feeding'conduit 13 and the

nozzles

4 and 7 and 10, respectively, are connected by

borings

17 and 20 and Y23 respectively, with the'feeding conduit 14. Thus'the

nozzles

2, 5, 8 and 3, 6, 9 and 4, 7, 10,

"respectively, each form a group ofnozzlesj- Ofcourseit would be" possible to obtainv difierent groupings by' different arrangements of the boringsp For blocks II to VIassociated to the'broad' side each of the slab (FIGURE 4) include together 60 nozzles so that the represented embodiment-has, nozzles. Of these 4 nozzles are in action on'each narrow side and 26 nozzles are in action on'each broad side of the slab so that 'of the 72 provided nozzles 60 are effective. H

In the example shown in FIGURE 6 other'valves of the nozzle blocks have'been closed so that Without any constructive modification ofthe apparatus with which the'action shown above has been obtained only 44 nozzles are active.- I t v Inthe represented embodiments, only the state ,open

' or closed has been assumed for each valve.f Of'course,

example it would be possible to connect-the nozzles 2, 3, V

and 4, 5 and-6,7, respectively, to the

feeding conduits

12 and 13 and 14, respectively,Whereby'cycled groupings 13/8, -9 etc. .would result. I r

A different construction of a nozzle block isillustrated by FIGURE 3." This nozzle rblock 32 againillustrated 3 I for one side of the slab Sal-"only, consists of

feedingv conduits

33 and 34 arranged concentrically with respect to' each other. The .inner pipefie is connected with the .outer pipe 33 by webs (not shown), The outer pipe 337,:

carries nozzles 35fthe 1 borings of, which communicate either'withthe annular surface lor fwith the inner-surface of the nozzle block 32 so that again groups of nozzles V areformed. V V

FIGURE 4shows the embodiment of FIGURES land 2 in 'us e with the casting ofaslabf I and ',VII designate the nozzle blocks spraying, onathe narrow sides of the slab, and II to VI designate parallelnozzle blocks spraying on the broadside of theslab.

I In FIGURESJS and 6 there are shown diagrammatically examples of the cooling effect for this-slab. The ver- ,the cooling action could be modified also by throttling the valves into a, position betweenppen and closed; This 1 would'o'f course, involve the drawbacks mentioned in the 30' the'feedingconduitsto theblocks should be increased.

The number of faces-required for the nozzle block will always hie-n+1; where n'isjthe number of groups of I nozzles on that particular; nozzle block;

iThe nozzles' corresponding infvertical direction with each, other 'must not necessarily be arranged in parallel planesperpendicularlvto theax'is of the ingot. Ap-

: plic ations 'may be found where-,thenozzles associated in 7 vertical direction tdeachotherare arranged in planes tical lines represent the nozzle blocks and areagain des-j' a ignated by' references I-VIL 'All nozzles of the nozzle;

block I-'-VII are arranged in a plane perpendicular to the axis of the slab. iThis'plane is designated by a and I othersoas'to be controlled by a common, valve. 1 'it corresponds to the level a infthe" secondary cooling f i zonetof'thef plant. All'jthese nozzlestform fgroupro ffi nozzles in this particular plane; Analogously fal-l' nozzles 3 to' 10ii1lu-stratefurther groups b to fin the. COT-j respondingplanes which all are parallel to each other. 7 In .accordance'with FIGUREjS the. valve of one fed 1 'ing' conduit for the nozzle. blocks I and VIIis closed.

so that the cyclic sequence of the action ofj'the nozzles parallel to the axis of the slab is,1,:1, 0, 1,11, 0; etc.

wherein 1 designates an open nozzle and 0 designate a closed nozzle- State P F Valve is indlca'tfid h I 1 ofv the no zles Spraying gwatr' 'on said' strand without permitting ternperature diflerencesin the solidified skin points of intersection of the nozzle blocks I to VII with 'the planeszq to fwith a ring; 'In each ofthe nozzle blocks II'and 'VI the valve of one other feeding conduit is closed.

so that the sequence obtained is: 0,1, 1, 0; 1-, lgetc;

positi'onresultingin the ms-1, 1,11, etc; "illhedescribed arrangement of the apparatus results, in the planes and means for closing sa dcondu ts selectively to effect ,which form an angle withthe axis of theingot,

I "In-order to reduceitherequired number of adjusting v'alveswhich may benecessary when particularly large slabs arecast which require a great number of I nozzle blocks the feeding conduit-s for nozzle blocks required to have the same cooling action mayib'e connected with each I clairnz j s I 1.: Apparatus for cooling/the strand-issuing from a continuous casting molda which comprises. a plurality of "nozzle blocks positioned in approximately. parallel col- 7 urnns" adjacent said strand, aplu'r'ality oflnoz'zles carried by each of said nozzleblocks and arranged'ito form apj proximately parallel'rows of nozzles,'each of said nozzle blocksincluding a plurality ofconduits, means coupling each conduit to a selected number of spaced apart nozzles,

1 changes of {the cooling ofisaid strand by selective control of the casting whichwouldinduce cracks therein. I

2. Anapparatus'as claimed'in claim l'which includes I l ,multi edgednozzle"blocks, thenumbertof faces of which In the nozzle blocks-III, IY andV all valves jar'ein open exceeds aboutone the number of nozzle groups, on the 1 particulargbloclgwhereby theinozzles are, arranged jalong one-face and on each other facethere is arranged one feeding conduit feeding one particular selected number of spaced apart nozzles.

3. An apparatus as claimed in claim 1 in which said nozzle blocks are formed of concentrically arranged feeding tubes the number of which corresponding to the number of nozzle groups on that particular block.

4. Apparatus in accordance with claim 1 in which said columns are positioned parallel to each other and to the axis of the strand.

rows are positioned parallel to each other and perpendicular to the axis of said strand.

References Cited by the Examiner UNITED STATES PATENTS 1,173,771 2/16 Cook 239450 2,789,328 4/57 Ackerrnan et a1 2257.2 2,871,529 2/59 Kilpatrick 22-57.2

MARCUS U. LYONS, Primary Examiner.

5. Apparatus in accordance with claim 1 in which said 10 MICHAEL V. BRINDISI, Examiner.

Claims

1. APPARATUS FOR COOLING THE STRAND ISSUING FROM A CONTINUOUS CASTING MOLD WHICH COMPRISES A PLURALITY OF NOZZLE BLCKS POSITIONED IN APPROXIMATELY PARALLEL COLUMNS ADJACENT SAID STRAND, A PLURALITY OF NOZZLES CARRIED BY EACH OF SAID NOZZLE BLOCKS AND ARRANGED TO FORM APPROXIMATELY PARALLEL ROWS OF NOZZLES, EACH OF SAID NOZZLE BLOCKS INCLUDING A PLURALITY OF CONDUITS, MEANS COUPLING EACH CONDUIT TO A SELECTED NUMBER OF SPACED APART NOZZLES,