US2553921A

US2553921A - Continuous casting apparatus

Info

Publication number: US2553921A
Application number: US87048A
Authority: US
Inventors: Jordan James Fernando
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-04-12
Filing date: 1949-04-12
Publication date: 1951-05-22
Anticipated expiration: 1968-05-22

Description

May 22, 1951 J. F. JORDAN CONTINUOUS CASTING APPARA; s

4 Sheets-Sheet 1 Filed April 12, 1949 l/ll/I/Il/I May 22, 1951 JORDAN 2,553,921

CONTINUOUS CASTING APPARATUS Filed April 12, 1949 4 Sheets-Sheet 3 INVENTOR:

J. F. JORDAN CONTINUOUS CASTING APPARATUS May 22, 1951 4 Sheets-Sheet 4 Filed April 12, 1949 INVENTOR- MXML;

Patented May 22, 1951 UNITED STATES PATENT FfFlE f 2,553,92i j V CONTINUOUS GASTING APPARATUS JamesFernando JordangHunting ton-Park, (la iii, M

' Appucatitnaptil 2, is rsgs'enaintzsiicis -1 Claim; (Cl. 22-573) My invention relates to the art er continu the solidified steel- Sli-iaip is drawn. These methods sufier from the disadvantage that it is extremely difiiciilt to -keep-the "surface of a bath of molten steel fi e item slag and/or surface-oxide films; and these methods also s'ufier from difiiculties ai isi-iig froifi the iact that it is necessary to feed the molten steel into the water-cooled mold at a "substantially-constant' rate, else the rate tr solid shape Withdrawal may get out of balance with the rate at which the molten steel is being introduced into the mold.

My invention is an apparatus for'continuous'l-y cast'i-ngsemi-finished steel, or o'thermet'al; Shapes that euminates' the mentioned. objectionable featui'e's of past and present casting methods. h My apparatus consist's of a water-cooled mold that is inserted into the bath of molten metal from a position that lies :abeve the upper face'of said bath, said water-tooled mold bein positioned so' that it extends below said surface of said bath of metal and eiitends partly above said surface (if-said bath. The casting opera= tion proceeds as the molten-metal flows into the mold opening that is submerged; 'solidifies into the desired shape within said mold; and continuously withdrawn,-'a's the final solidified shape,- from the mold opening that is positioned above said surface of said bath. My casting appar'a tus thus permits the continuous withdrawal of v the desired metal shape up from, and out of, the bath of molten metal. Furthermore, my apparatus may be operated so that it will con tinuously cast either solid isha'pes-such as rounds, squares,- sheet, plate, etc, or said ap= paratus may be employed to cast hollow shapes such as pipe.

Figure 1 shows a' form' of my casting appara tus in position in a bath of molten metal.

Figure 2 shows section Z Z, indicated in Fig= ure 1.

Figure 3 shows my casting apparatus arranged to cast pipe. 7 Y.

Figure '4 shows'section 1-4, indicated in Fig ure'3.

12 1 Figure v5 snows a mbd-meatiiin ei my apparatus of Figure -1=.

Figure 6 shows another modification o f any apparatus of Figure l.

Figure =7 shows "still another modification of my apparatus of Figure 1.

Figure 8 shows' my apparatus ofFigure lamedified to east sheet on-plate. Figure 9 shows another modification of apparatus.

in Figures 1 and '2; the mold is :iermd of a 'metal pipe is that open at the top and bot tom; Mold pi e =l5 is eooIed-bymeans 'of a eon: centric arrangement of pipes li and is; which pipes I1 and it are spaced-"around mbld -formmg pipe It, so as" to form water circuiating' spaces ISA and 15B: c'es 45A and lte are separately closed at' their ps' by means of water: jacket top end lfiApad aid spaoe'sdliA and [5B are "confined t6 join each other by Water jacket bottom end A that connects pipe 16 with mold pipe I E and saidspaceS are permitted to join each other by connecting space l8 that is' formed as pipe 1 reaches not quite down to water -jacket bottom end *I 8Aa j'At, =or near, the top of the water 'jacketed mold, pipe connection l3A penetrates the airangement to connect'siaace ISA with a source. of cooling"- watei' I31; and at; or near, said top" of the water jacketedmold, pipe connection 12A penetrates the arrangement to v connect with space IS'BysO as' to pefinitxth'eheated water I2 to leaversaidispace I513. That .1301 mm of pipe 16' which is tobeexposd .to direct contact with liquids-20 and 22, and that portion of pipe It which is't'o' lie immediately above-slag layer 20, is shown c'oyered with refractory cover ing l4, said covering-f4" beingoaused to entirely cover the" submerged portion of pipe It; except for "opening 19' that connects thecasting zone withinpip l5 withinolteii ine'tal bath22l. V Y

The cooling water I3 enters space 15A thi' u connection 13A; flows down thru' saidspac'e' 15A; cooling mold pipe -|"5" as so flows; -and then carries the absorbed heat ewe-y from spacel iBA by entering spacel5B' via space. 18'; said space I5B conducting the heated water 'out of the, process via connection l-2n=cooling pipe l6 and covering 1'4 as the water flows upthru space [:53 The casting apparatus of-Figures 1 and' 2 may be placed in-op'era-tion byifirst inserting a length; of the metal thatis to :be, east 11 inthemold cavity within moldpipe 3P5, said insert met being large enough in diameter; to substanti; I, 1y fill" said cavity, yet not so large that said inserted metal [1 cannot be readily moved up and down withinsaid cavity; Inserted metal H shouldextend almost to the bottom of mold pipe I5, and should rise above said mold pipe I far enough to connect with lifting means If] (not shown).

With inserted metal II in place, and with cooling water I3 circulating thru spaces IEA and H53, the casting apparatus may be prepared for immersion by strongly preheating refractory covering I4 that forms the bottom of the mold, particularly should opening I9 be strongly preheated. -One of the simplest methods of pre heating opening I9 is to lower the casting apparatus until the bottom of said opening I9 is an inch, or so, above the molten slag layer 20, so as to permit said layer 20 to preheat opening I9 by radiation. Covering Hand opening I9 may be preheated also by simply playing flame thereupon.

With refractory covering I4 and opening I9- preheated to a temperature that lies above the melting point ofthe metal that is being cast, the casting apparatus may be lowered into casting position by slowly lowering opening I9 into metal bath 22 far enough to prevent slag layer from entering opening l9 during the casting operation that is to follow. This lowering operation should be performed so that slag 29 does not enter opening I9 as the apparatus is immersed in metal bath 22. One way to avoid trapping slag 29 in opening I9 is to thicken up slag layer 20 in the vicinity of the proposed point of immersion, and, then, by pushing back the thickened slag, expose an area of bare molten metal into which the casting device may be introduced.

At the moment when preheated opening I9 is immersed far enough below the surface of metal bath 22 to cause said metal to flow into contact with the bottom end of inserted shape I I to form zone of metal solidification 9, means Ii] should be caused to slowly start to lift metal shape i I up from, away from, and out of, the mold formed by pipe mold I5, and, as said shape I I is slowly lifted out of the mold, the molten metal that forms bath 22 will enter pipe I5 via opening I9, and will thereupon fiow towards, and will contact, said zone of solidification 9. Thus, metal shape II that is being continuously withdrawn out of the top of pipe mold I5 is being formed, and built up, at the zone of contact between said shape I I and the molten metal that flows into said mold via opening I9. This zone of contact 9, being at the same time the zone of solidification 9, is definable as that point where the cooling metal has cooled enough to possess sumcient strength to support its own weight, in view of the lift exerted within said mold by atmospheric pressure acting downward upon surface 20A.

The general shape and location of zone of metal solidification 9 will depend upon the rate at which shape I l is being lifted out of pipe mold I5. Thus, at a comparatively slow rate of shape I I withdrawal, the general contour of zone 9 may be similar to zone 9 in Figure 1. As the rate of shape II withdrawal is increased, however, zone 9 will elongate out as the last point of metal solidification-the peak at the center of zone 9- moves up away from the bottom of the mold. The rate of withdrawal of shape II may be increased until the peak that represents the last point of solidification has risen to a point that lies so far above bath surface 20A that atmospheric pressure on said surface 20A can no longer support the molten and/or pasty metal that lies at the center of shape II. When this happens, a hole will begin to appear in shape I I.

When the rate of withdrawal has been in- 4 creased until a hole begins to appear at the ceriter of cast shape II, my casting apparatus is producing cast pipe.

Figures 3 and 4 show my apparatus producing cast pipe. Here, the concentrically-arranged mold is formed as pipes 3| and 30 are spaced around mold pipe 31. Cooling-water 29 is shown flowing down thru space 31A, into space 31B via passage 39, up thru space 3113, and out of the mold via stream 28. The outside of the casting device is shown protected against heat by refractory covering 32, said covering 32 being penetrated at the bottom by opening 96, up thru which the molten metal in metal bath 35 fiows to form a pool of molten metal within mold pipe 31. Surface 38 is the surface of said metal pool withing mold pipe 31.

When the rate of withdrawal of shape II in Figure 1 is increased until a hole is being formed at the center of said shape II, said hole will contain a partial vacuum if metal bath 22 consists of metal that does not evolve gas during the casting operation, and said vacuum Will tend to lift, or suck, the molten metal up into mold pipe I5. When this partial Vacuum is destroyed, either as the result of the evolution of gas during the solidification of the metal or as the result of the cutting off of shape II after said shape II has passed by lifting means Ill-thus permitting at: mospheric pressure to gain entry into said evacuated hole within shape II, then the level of the molten metal within mold pipe I5 will fall below that level maintained with the help of said vacuum.

I Once atmospheric pressure has gained entry into the evacuated hole within said shape I I, my apparatus will continuously cast metal pipe in the manner shown in Figures 3 and 4. Here, pipe 21 is being withdrawn from mold pipe 31 so fast that the chilling effect of cold mold pipe 31 is not sufficient to cause the zone of solidification 49 to bridge entirely across the mold cavity formed within mold pipe 31, with the result that when pipe 21 has been lifted above molten metal surface 38, the casting operation ceases, and the resulting pipe 21 will possess an inside diameter that is substantially equal to the diameter of said surface 38.

The inside diameter of pipe 21 may be increased by increasing the rate of withdrawal of said pipe 21, and, conversely, the inside diameter may be decreased by decreasing the rate of withdrawal. In fact, said inside diameter may be decreased to that point where zone of solidification 49 will bridge entirely across the mold cavity, resulting in the conversion of the operation into the production of a solid shape, as in Figure 1. And so, my apparatus may be shifted from solid shapes to pipe, and from pipe to solid shapes, with only a slight change in the method of operating said apparatus.

Surface 38 may be expected to be slightly below surface MA, due to the viscosity of the metal that lies adjacent to zones 40; however, the pressure of gas 26 upon said surface 38 will effect the relative levels of said surfaces.

Gas 26 may be the atmosphere, or said gas 26 may be a gas selected to protect surface 38 from oxidation. Thus, when casting steel, copper, aluminum, magnesium, brass, bronze, etc., gas 26 may be nitrogen or carbon monoxide.

The pipe casting operation of Figure 3 may be started in the described manner, or said oper-' ation may be started by first inserting in mold pipe 31 a pipe whose outside diameter is only slightly" less than the-inside diameter pipe and then preheating opening 33" in thedescribed ma'nner'prior w inserting-the casting 'device iiitd are I Thesolid shap'e" shown-in Figures 1 and 2 need riotne'ce'ss'arily be'round, but may" b any other desired shape for example; shape H may be are oval, square, rectangle; a hexagorrwith fiat facesi a hexagon with concave faces, etc;

Means Hi and/or may be any convenient means for lifting. the cast shape out of the continuous mold. Means" H2 ans br- 25 may be the human hand, rolls; ac cranegahoistg. wri'ia'ignetZ-Ja hydraulic jack, etc. The main-1 requisite isithat said means lzll-andgor 25becapable-of-.lifting said cast shape in a uniform and controllable man ner.

Mold pipe l5 and/or mold pipe 31 maybe constructed of any metal whosethermal conductiv ityis high. Thus; for example; the mold? pipe may be madeofcopper, brass; bronze, steel; etc. Theinside diameter of the mold pipe" may ordinarily be uniform from top to bottom; for the'normal shrinkage of most meta-ls will provide the'clearance required between the cast shape and the mold pipein order to prevent binding therebetween; If the device is being emplb'yed to cast a metal that tends to bind, then the inside diameter of the mold pipe may be tapered slightly, big end up.

The function of the refractory coverings [4 and/or 32 on the sides and bottoms of pipes 16 and/or is to prevent the cooling action of said pipes from cooling the contacting metal bath to the point of solidification; for, if the metal starts to solidify on the outside of the casting device, it may not be long before the cast shape will be welded to metal that has solidified on said outside of the device. This would quickly bring the casting operation to a halt. The constriction of the bottom openings of said molds by means of refractory coverings is in keeping with this effort to deliver the molten metal to the zones of solidification. It is my intention that the refractory openings I9 and 36 be heated so high that no metal will solidify in the immediate vicinity of said openings.

This function of the bottom opening of my mold is the more important, the closer the temperature of the metal bath is to the melting point of the metal. If a metal is being cast out of a bath whose temperature lies so far above the melting point of said metal that said bath shows little tendency to solidify in the immediate vicinity of, or within, said opening, even though said opening is not constricted in the manner shown in Figures 1, 3, 6 and 9, then a mold bottom similar to Figures 5 and 7 may be employed. Figure 5 serves to emphasize the fact that the function of a refractory covering, such as 5|, is to prevent the molten metal from solidifying in the vicinity of the outside of the bottom opening of the mold, such as 52; that is, the extension of said covering 5| up along the sides of mold 46 is not necessarily required for the successful operation of my mold, such extension-as shown in Figures 1 and 3-merely aids in preventing the metal from solidifying against the side of the mold. Such solidification of metal on the side of the mold will not interfere with the operation of said mold unless the solidification process extends to the bottom of said mold. In Figure 5, shape is shown being drawn out of mold 46, said shape 45 being formed at zone of solidificati0n.50 as molten metal 49 flows into said mold via o ening-52 Opening 52 in bottom covering" 5| conforms in size and" shapeto the bottom-- openingof mold pipe 46A. Slag layer 4-1 confacts metal bath- 49 at slag-metal interface 48 In Figure 7, shape B lis shown being drawn-out" of mold 62, said shape 6| being built up at zone of solidification [it as molten metal- 9'5flowsinto tli'e'- mold" via opening 61. In Figure '7, the solidification'of'molten metal 65* on the-bottom'of' mold 62' isprevented by'forming' said mold bottom of ametal' Whose thermal conductivity is lowhea-t resisting steel containing 25%- chromium and 12% nickel, for'example-Jn comparison with the thermalconduc'tivity" of the mold pipe that forms the casting cavitya mold pipe of copper, for" will offer a hotter'surface to-bath 55; the thicker said 25-|2 bottom, the'hotter'will be the-surface exposed to ba'tli 65: The arrangement of Figure I"willbe"eii ective only if" the temperature gradient tliru 'said bottom is so stcep'that the outsi'de'sur-- face-the' surface in contact with bath" 6'=-ofsaid bottomis above the melting point of' thei metal that being cast asituation that mayonly be achieved when the melting point of the metal that is being cast is well below the melting point of said 25|2 bottom.

The arrangements of Figures 5 and 7 may be made more effective by extending the mold bottom or the mold bottom covering so that they constrict the opening thru which the molten metal must fiow in order to reach the zone of solidification, as is shown in Figures 1, 3 and 6. In Figures 1 and 3, this constriction of the size of openings l9 and 36 by coverings over the mold bottoms will improve the operation of the molds by decreasing the likelihood of the solidification of metal within, or immediately outside of, said openings; for, not only does such constriction remove said openings to a position more remote from the effect of the cooling water, but the resulting smaller openings offer less exposed refractory surface to the molten metal passing thereby, resulting in the more easy maintenance of said openings in the hot condition required if said metal is to be prevented from solidifying therein.

Figure 6 shows how a casting device of the type shown in Figure 7 may be improved in a manner that is analogous to the improvement shown in Figures 1, 3 and 9. In Figure 6, shape 53 is being drawn out of mold 54, said shape 53 being built up at zone of solidification 58 as metal 51 enters the mold via opening 59. Opening 59 is formed by metal bottom 60, said bottom 60' being extended to constrict said opening 59 in the manner indicated. Said extension removes opening 59 to a position more remote from the cooling water within the mold, resulting in the more easy maintenance of said opening in the highlyheated condition that is required if metal is to be prevented from solidifying in, or immediately outside of, said opening 59.

The improved design of Figures 1 and 3 may be still further improved by a design similar to the one shown in Figure 9. Here, shape 10 is being drawn out of mold 12, said shape 10 being built up at the zone of solidification shown within said mold 12. Water 13 is the cooling-water that is being circulated within mold 12. Metal bath 15 is shown flowing into said mold 12 thru an openamsspa ing H formed by refractory covering 14. said covering I4 being caused to extend into the bottom opening of said mold Z2, so as to assure the,

delivery of metal 15 to within mold 12 before the solidification process begins.

While Figure 2 is section 2-2 in Figure 1, and shows the cast shape to be round in cross section, Figure 1 may be employed also to portray a section thru my apparatus when said apparatus is being employed to cast sheet or plate, in which case section 22 must be portrayed substantially as shown in Figure 8.

In addition to steel, my casting apparatus may be employed to cast copper, brass, bronze, aluminum, cast iron, magnesium, etc.

Having now described several forms of my invention, I wish it to be understood that my invention is not to be limited to the specific form or arrangement of parts herein described and shown, except insofar as such limitations are specified in the appended claim.

I claim as my invention:

In a continuous casting apparatus having a container for holding a bath of molten metal, an open-ended, water-cooled mold suspended in the container with its upper end above the molten metal level in the container and its lower end below said molten metal level, and means for withat the lower opening in the mold an opening smaller than that of the mold, said covering pre venting molten metal from solidifying on any part of the mold except the mold cavity, which is filled through the opening in said covering. JAMES FERNANDO JORDAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 750,253 Byrnes Jan. 26, 1904 1,088,171 Pehrson Feb. 24, 1914 1,444,953 Crane Feb. 13, 1923 1,727,191 Bailey Q. Sept. 3, 1929 2,136,394 Poland et al Nov. 15, 1938 2,195,809 Betterton et a1 Apr; 2, 1940 2,203,679 Edwards June 11, 1940 2,225,415 Junghans Dec. 17, 1940 2,405,355 Harrison Aug. 6, 1946 2,496,235

Rossi Jan. 31, 1950