US3439730A

US3439730A - Method and apparatus for continuous casting of metal in horizontal direction,especially for continuous casting of thin metal bands,plates or the like

Info

Publication number: US3439730A
Application number: US566588A
Authority: US
Inventors: Gunther Moritz
Original assignee: Vereinigte Aluminium Werke AG
Current assignee: Vereinigte Aluminium Werke AG
Priority date: 1965-07-24
Filing date: 1966-07-20
Publication date: 1969-04-22
Anticipated expiration: 1986-04-22
Also published as: FR1486340A; AT264026B; NO115920B; GB1090518A; BE683754A; CH445727A; LU51610A1; NL6609857A; SE302829B

Description

0 3 7 9, NG 31N I 4am OTA mC NSE www Gmb NIE ITH www. R mco SmnUSOJ zwpwl U A WNMLO RILP2 TA ONT. ,y MOCSl CEDu .RPMJ F .MH S UWTF TIE mmm AEN PRI PIH ADT DLF NAO Am DO OZ wm EO MH April 22, 1969 NVENTOR gaf/fitr Manuf@ ATTORNEY :United States Patent O1 ice 3,439,730 Patented Apr. 22, 1969 ,968 Int. Cl. B22d 11/02, 15/00 U.S. Cl. 164-82 15 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for casting metal strands in which a stream of molten metal is passed in substantially horizontal direction through a chill and the thus formed metal strand, after complete solidification, is guided likewise in substantially horizontal direction over rigid guide means spaced downstream from the chill, whereas the strand portion intermediate the chill and the rigid guide means is supported on a plurality of rollers which are spaced in direction of movement of the strand and mounted movable in substantially vertical direction.

The present invention relates to a method for continuous casting of metal in horizontal direction, especially for continuous casting of thin metal bands, plates or the like and an apparatus for carrying out the method.

For economic reasons, it is necessary to cast thin metal bands with a high casting speed. During continuous casting of metal the metal is passed in liquid form through a chill, and when high casting speeds are used, the metal emanating from the outlet end of the chill has still a liquid core. The band thus cast is not absolutely straight and has a certain roughness, for instance exudations, so that when the band after leaving the outlet end of the chill is passed onto rigid guide means spaced only a short distance from the outlet end of the chill, the mentioned deviations from the exact desired form of the band will produce in the latter in the reg-ion of the outlet end of the chill transverse forces which may lead to a fracture of the band in this region.

'It is an object of the present invention to provide for a method and apparatus in which the aforementioned diiiiculties in continuous casting of metal in horizontal direction are avoided.

It is an additional object of the present invention to provi-de for a method and apparatus in which the cast metal band or plate is supported between the outlet end of the chill and subsequent rigid guide means in such a manner to avoid creation of transverse forces in the band which could lead to a breakage of the same.

With these objects in view, the method of the present invention for continuous casting of thin metal strands such as bands, plates and the like in substantially horizontal direction mainly comprises the steps of guiding a thin stream of molten metal in substantially horizontal direction through a chill to solidify the molten metal at outer portions thereof so as to form a metal strand, guiding the metal strand thus formed after complete solidification in substantially horizontal direction over rigid guide means spaced in direction of movement of the strand away from the chill, and supporting the strand intermediate the chill and the rigid guide means at a plurality of points arranged spaced from each other in the direction of movement of the strand and movably in substantially vertical direction.

The method includes preferably further the step vof exerting at each of the aforementioned points an upwardly directed force on the strand of such a magnitude that the total weight of the strand between the chill and the rigid guide means is counterbalanced by the upwardly directed forces.

The apparatus according to the present invention for continuous casting of a thin metal strand such as a band, plate and the like in substantially horizontal direction mainly comprises chill means formed with a substantially horizontal passage therethrough of a cross section substantially equal to the cross section of the strand to be produced and having an inlet end and an opposite outlet end, means for continuously feeding molten metal into the inlet end of the passage so that the molten metal passes through the passage and leaves the outlet end of the chill means as a strand of metal solidified at outer portions thereof while still containing a core of molten metal, a plurality of support means arranged spaced from each other in direction of movement of the strand and respectively engaging the latter at spaced portions of its bottom face, mounting means mounting the support means movably in vertical direction, and biasing means cooperating with said support means for exerting on the strand upwardly directe-d forces so as to counterbalance the weight of the strand between the chill and the rigid guide means.

The support means are preferably in the form of rolls each turnably supported at one end of a 'double-armed lever and the biasing means are preferably in the form of weights connected to the other end of each lever. The apparatus may also include means for passing a cooling liquid, such as water, along the surfaces of the strand leaving the outlet end of the chill means and means arranged between a pair of successive support rolls for preventing passage of cooling water along the surface of the strand beyond the last-mentioned means so as to maintain the strand of metal at a predetermined temperature.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specic embodiments when read in connection with the accompanying drawing, in which:

FIG. 1 is a schematic partly sectioned side view of the apparatus according to the present invention;

FIG. 2 is a partial cross section illustrating the left portion of the apparatus, as viewed in FIG. 1, at an enlarged scale;

FIG. 3 is a front view of one of the supporting rolls;

FIG. 4 is a partial cross-sectional view of the apparatus and illustrating means for preventing passage of cooling water along the surfaces of the cast metal strand; and

FIG, 5 is a partial cross-sectional view similar to FIG. 4 and illustrating another embodiment of the means for preventing passage of cooling water along the strand of cast metal.

Referring now to the drawings, and more specilically to FIGS. l and 2 of the same, it will be seen that the casting apparatus according to the present invention includes a water-cooled me-tal mold or chill 1 formed with a passage 2 therethrough having an inlet end 2 and an outlet end 2" and a cross section substantially corresponding to the cross section of the metal band or the like to be produced by the casting apparatus. A container 3 having walls of hea-t-resistant material is arranged at one side, that is the left side as viewed in FIGS. l and 2 of the chill -1 and molten metal is continuously fed into the container by means of known construction not shown in the drawing so as to maintain in the container 3 a bath 3a of liquid metal having a level above the inlet opening 2 of the chill 1, and the container 3 is formed in the side wall thereof abutting against the chill 1 with an opening communicating with the inlet end 2 of the passage 2 through the chill so that molten metal from the bath 3a in the container 3 will continuously flow through the inlet end 2 into the passage 2, wherein the metal is at least at outer surface portions thereof solidified so as to leave the outlet end 2" of the passage as a strand or layer of metal 4 having an inner core 4' of liquid metal.

The chill 1 is formed in the region of the outlet end 2" of the passage 2 therethrough with a plurality of openings 7 directed with their outer ends toward the strand of metal 4 so that cooling water fed into the interior of the chill through a conduit 1a may flow through openings 7 in streams of cooling Water 8 along the outer surfaces of the metal strand 4 to expedite further cooling of the latter. As shown in FIG. 2 the cooling water will not flow only along the upper face of the strand 4 but also along the bottom face thereof to which it will adhere due to surface tension. The more or less solidified strand 4 is guided over a plurality of support means which are preferably in the form of movably mounted rolls onto rigid guide means 6 spaced in direction of movement of the band a considerable distance from the chill 1. As shown in FIG. 2 each of the rolls 5 is turnably supported at one end of a doublearmed lever 5a which in turn is tiltably mounted intermediate its ends on mounting means 5b. Biasing means lwhich are preferably in the form of weights 9 are respectively connected to the other ends of the levers 5a so as to press the rolls carried by the levers against the bottom face of the strand 4. The weight 9 and the two arms of each lever 5a are dimensioned in such a manner that the force with which each roll 5 is pressed in upward direction against the bottom face of the band 4 is substantially equal to the weight of the portion of the band supported by the respective roll, that is to the weight of the band portion between successive dotted vertical lines 10 indicated in FIGS. 1 and 2. The rolls 5 are preferably constructed in such a manner as to permit fiow of cooling water along the bottom face of the band beyond the respective roll and for this purpose each of the rolls 5 may `be provided with a plurality of circumferential grooves 11 as shown in the front view of FIG. 3 so that the cooling water which flows at high speed along the bottom face of the band may pass through the grooves 11.

Subsequent to the rigid guide means 6 or in the region of the latter, the continuously cast band 4 is divided into sections, coiled up, rolled, or further acted upon by means not Vshown in the drawing and not forming part of the present invention.

The rigid guide 6 is spaced from the chill 1 at such a distance that no transverse forces can be transmitted to the region of the band at the outlet end of the passage 2 which are great enough to cause breakage of the band which in this region is only partly solidified.

The distance between the rigid guide means and the outlet end from the chill can be held the shorter, the thinner the band and the more plastic the metal from which the band is formed. The distance between successive rolls should be the smaller, the more flexible the band.

The method according to the present invention can be improved by reducing the action of the cooling water flowing along the cast Iband by deflecting the cooling water from the outer surface of the band before the latter is completely solidified. The band remains in this case in plastic condition over a longer part of the distance between the chill and therigid guide means so that reactions from the rigid guide means 6 onto the portion of the band leaving the chill are suppressed in a better manner. In this way, a cooling of the band 4 to the temperature of the ambient air will be prevented.

Two modifications of means for detiecting the cooling water from the outer surface of the band 4 are shown in FIGS. 4 and 5.

The means for deflecting the cooling water 8 from the outer surfaces of the band 4 shown in FIG. 4 include a frame 12 fixedly mounted about the band 4 and carrying a pair of wiper blades 13 of heat-resistant elastic material, for instance Teflon, which elastically engage with end edges thereof the upper and lower faces of the band 4 so as to deflect the streams of cooling water 8 from the surfaces.

A different arrangement for the same purpose is shown in FIG. 5 in which a plurality of nozzles v14 are provided through which compressed air from a nonillustrate'd source of compressed air is blown in form of air streams against the top and bottom faces of the band 4, which air streams are guided by xedly mounted deflector blades 15 in such a manner that the streams of cooling water 8 passing along the top and bottom faces of band 4 are deflected therefrom as shown in FIG. 5.

The wiper blades 13 as shown in FIG. 4, respectively, the nozzles and

deiiector blades

14 and 15 are shown in FIG. 5, are arranged either in the space between the outlet end of the passage 2 through the chill 1 and the first of the rolls 5, between the first and the second of the rolls 5 or between any of the pair of rolls depending on the metal to be cast in the apparatus, the casting speed and the thickness of the strand produced.

The following data are given in a nonlimiting sense by way of an example.

In an apparatus as above described in which the distance between the outlet end of the chill 1 from the entrance end of the rigid guide means 6 was 1,200 mm. and in which seven rolls of a diameter of 40 mm. were arranged equally spaced from each other between the chill and the rigid guide means, a band from Al 99.5 with a cross section of l0 x 150 mm. has been cast with a speed of 1,300 mm. per minute. The means for defiecting the cooling water from the faces of the cast strand were arranged in this case between the first and the second roll, counted in the direction of movement of the band from the chill, and in this case the end temperature of theI band was 200 C.

With the same arrangement a band of a cross section of 15 X 400 mm. has been cast from an alloy of zinc with 4% of aluminum with a casting speed of 900 mm. per minute. The end temperature' of the band was about C.

Electrolytic copper has been cast with the same arrangement whereby the means for deflecting the cooling water have been arranged between the second and the third roll. The end temperature of the band was, in this case, 300 C.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of methods and apparatus for continuous castings of thin metall bands or the like in substantially horizontal direction differing from the types described above.

While the invention has been illustrated and described as embodied in a method and apparatus for continuously casting a thin metal band or the like in substantially horizontal direction, it is not intended to be limited to the details shown, since' various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore', such adaptations should and are intended to be comprehended Within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A method for continuous casting of thin metal strands such as bands, plates, and the like in substantially horizontal direction comprising the steps of guiding a thin Stream of molten metal in substantially horizontal direction through a chill to solidify the metal at outer portions thereof so as to form a metal strand; guiding the thus obtained strand of metal after complete solidiication in substantially horizontal direction over rigid guide means spaced in direction of movement of the strand away from the chill; and yieldingly supporting said strand intermediate said chill and said rigid guide means at a plurality of points arranged spaced from each other in said direction and movably in substantially vertical direction in such a manner as to avoid creations of transverse forces which could lead to breakage of the strand.

2. A method as set forth in claim 1 and including the step of exerting at each of said points an upwardly directed force on the strand of such as magnitude so that the total weight of the strand between said chill and said rigid guide means is counterbalanced by the upwardly directed forces.

3. A method as set forth in claim 1 and including the step of guiding cooling water over the outer surface of the strand during part of the passage of the latter from the chill to the rigid guide means.

4. A method as set forth in claim 3, and including the step of deecting the cooling water away from the strand at a pre'determined distance from said chill so as to maintain the temperature of the strand higher than the temperature of ambient air.

5. A method as set forth in claim 1, wherein said metal strand is cast with a thickness of less than 30mm.

6. Apparatus for continuous casting of thin metal strands such as bands, plates, and the like in substantially horizontal direction comprising, in combination, chill means formed with a substantially horizontal pas,- sage therethrough having a cross section substantially equal to the cross section of the strand to =be produced, said passage having an inlet end and an opposite outlet end; means for continuously feeding molten metal into said inlet end of said passage so that the molten metal passes through said passage and leaves said outlet end as a metal strand solidified at outer portitons thereof while still containing a core of molten metal; rigid guide means spaced from said outlet end of said passage for guiding the strand of metal after the same has completely solidified; a plurality of support means arranged spaced from each other in direction of movement of said strand between said outlet end and said rigid guide means and respectively engaging the strand at spaced portions of its bottom face; mounting means mounting said support means movably in vertical direction; and biasing means cooperating with said support means for exerting on said strand upwardly directed forces so as to counterbalance the weight of the portion of the strand between said chill and said rigid guide means.

7. An apparatus as set forth in claim 6 and including means for passing a cooling liquid along the surfaces of said strand leaving the outlet end of said chill means.

8. An apparatus as set forth in claim 7, wherein said chill means is in the form of a hollow water cooled mold formed about said outlet end of said passage therethrough with a plurality of openings for discharge of cooling water from the interior of the mold onto the surfaces of the metal strand leaving the outlet end of the passage. 1

9. An apparatus as set forth in claim 7, wherein said support means are formed at portions thereof engaging said bottom face of said strand with grooves permitting the cooling water to pass therethrough.

10. An apparatus as set forth in claim 7, and including means arranged upstream of one of said support means for preventing passage of cooling water along said surfaces of said strand beyond said last mentioned means.

11. An apparatus as set forth in claim 6, wherein said support means are respectively constituted by rolls, wherein said mounting means are in the form of double-arm levers tiltably supported intermediate the ends thereof and each turna'bly supporting a respective one of said rolls at one end thereof, and wherein said biasing means are constituted by weights respectively connected to the other ends of said levers.

12. An apparatus as set forth in claim 11, and including means for passing cooling water along the surface of said layer, said rolls being formed with peripheral grooves permitting the cooling Water to pass therethrough.

13. An apparatus as set forth in claim 12, and including means arranged upstream of one of said rolls for preventing passage of cooling water along the surface of said strand lbeyond said last mentioned means.

14. An apparatus as set forth in claim 13, wherein said last mentioned means includes a pair of lwiper blades from flexible material arranged to respectively engage the upper and lower face of said strand so as to deflect cooling water owing along said faces therefrom.

15. An apparatus as set forth in claim 13, wherein said last mentioned means includes nozzle means directed toward the upper and lower face of said strand for blowing streams of compressed air against said faces and dellector blades cooperating with said nozzle means for deflecting said air streams in such a manner so as to decct cooling water away from said faces.

References Cited UNITED STATES PATENTS 2,284,503 5/ 1942 Williams 164-283 X 2,895,190 7/1959 Bungeroth et al 164-282 3,107,404 10/1963 Armand et al 164-282 X 3,286,309 11/1966 Brondyke et al. 164-82 X FOREIGN PATENTS 626,982 1/ 1963 Belgium. 762,513 ll/ 1956 Great Britain.

J. SPENCER OVERHOLSER, Primary Examiner. R. SPENCER ANNEAR, Assistant Examiner.

U.S. Cl. X.R. 164-282