US3805877A

US3805877A - Continuous casting apparatus employing an oval-ended pouring spout

Info

Publication number: US3805877A
Application number: US00289722A
Authority: US
Inventors: G Ward
Original assignee: Southwire Co LLC
Current assignee: Southwire Co LLC
Priority date: 1972-09-15
Filing date: 1972-09-15
Publication date: 1974-04-23
Anticipated expiration: 1991-04-23

Abstract

An improved pouring spout for use in a continuous casting system including a rotatable casting wheel defining a peripheral groove having a dimension ratio which includes a major width and a minor depth, with a continuous band surrounding a portion of the peripheral groove to form an arcuate mold having a crosssectional area which includes major and minor axes, and wherein a supply of molten metal is transferred from a supply source, through the improved pouring spout for discharge into the arcuate mold. The improved pouring spout is formed to include discharge opening means supported adjacent an entrance of the arcuate mold, with the discharge opening means including major and minor axes aligned with the mold major and minor axes, and wherein the pouring spout includes a molten metal transfer passageway which is slightly smaller in cross-sectional area adjacent the discharge opening means. The improved pouring spout permits the molten metal to be transferred from the supply source to the arcuate mold at a flow rate approaching the flow rate of molten metal moved by the arcuate mold so as to substantially reduce the turbulence developed in the arcuate mold.

Description

United States Patent Ward 3,805,877 [451 Apr. 23, 1974 Attorney, Agent, or Firm-Van C. Wilks; Herbert M. Hanegan CONTINUOUS CASTING APPARATUS EMPLOYING AN OVAL-ENDED POURING SPOUT George C. Ward, Carrollton [57] ABSTRACT An improved pouring spout for use in a continuous Southwire Company, Carrollton, Ga.

[75] Inventor:

Assignee:

casting system including a rotatable casting wheel defining a peripheral groove having a dimension ratio 22 Filed: Sept. is, 1972 Appl. No.: 289,722

which includes a major width-and a minor depth, with a continuous band surrounding a portion of the peripheral groove to form an arcuate mold having a cross-sectional area which includes major and minor axes, and wherein a supply of molten metal is transferred from a supply source, through the improved pouring spout for discharge into the arcuate mold.

The improved pouring spout is formed to include discharge opening means supported adjacent an entrance with the discharge opening means The improved pouring spout permits the molten metal to be transferred from ts w... h m w Wm R mu a .mP m a 6 h s m dr nt am e 6 mm n m .mo mm ma w rd Fm ac m.m

slightly smaller in cross-sectional area adjacent the of the arcuate mold discharge opening means.

88X mm 44 mm m ..M mm m s m m fa W.mP CAUUU W MZ S m R wEwammO A Ph e T- rT f N SGPG MD T E999A n%%m, NHHHN U373G m flwu ,F. l Maw 33 1,575,686 7/1969 France................................ 164/278 1,483,468 4/1967 France................................ 164/278 the supply source to the arcuate mold at a flow rate approaching the flow rate of molten metal moved by Primary Examiner-J. Spencer Overholser' the arcuate mold was to substantially reduce the tur- Assistant Examiner-John E. Roethel bulence developed in the arcuate mold.

12 Claims, 11 Drawing Figures PATENTED APR 2 3 i574 SHEET 1 BF 2 FIG 1 l l FIG 2 30 FIG %ATENTED APR 23 I974 SHEET 2 UF 2 FIG FIG 8 m a 1 w, 9 Q H w FIG IO FIG FIG

CONTINUOUS CASTING APPARATUS EMPLOYING AN OVAL-ENDED POURING SPOUT BACKGROUND OF THE INVENTION This invention relates to a casting system and is more particularly concerned with a casting system having a movable mold operable for forming a continuous length of material.

A typical casting machine for continuously casting metal includes a rotatable casting wheel defining a peripheral groove, a flexible band surrounding a portion of the casting wheel and defining with the peripheral groove an arcuate mold, a molten metal supply source positioned adjacent the arcuate mold, and a pouring spout connected in flow communication between the supply source and the arcuate mold. The molten metal flows from the supply source through the pouring spout into the arcuate mold, and the casting wheel continuously rotates to carry the molten metal from the entrance to the exit of the arcuate mold. Coolant is applied to the external surfaces of the casting wheel and flexible band to extract the heat from the molten metal which results in solidifying the molten metal, and the solidified metal is extracted from the peripheral groove of the casting wheel as the metal reaches the end of the arcuate mold.

During the operation of the casting machine the rotationalspeed of the casting wheel and the flow of metal from the supply source to the arcuate mold are controlled'by the machine operator or by an automatic control system to maintain a level or pool of molten metal in the arcuate. mold. When the casting machine is first placed in operation, the casting wheel is usually rotated at a slow speed and the metal is poured at a relatively high rate of.flow from the supply source until the pool of metal is established in the arcuate mold and the lead end of the cast-bar has been'extracted from the casting wheel and led to the rolling mill or other subsequent processing equipment. When the pool of molten metal has been properly established and the equipment isready for higher capacity operation, the operator increases the rotational speed of the casting wheel and adjusts theflow of molten metal to continuously maintain the pool of molten metal in the arcuate mold. After the higher capacity casting has been established, the main control function'of the operator is achieved by adjusting the flow of molten metal from the supply source into the arcuate mold. This is usually accomplished with a metering pin which varies the opening between the supply source and the pouring spout, and

results in more or less molten metal flowing through the pouring spout.

In the earlier continuous casting system utilizing an arcuate mold formed-by a peripheral groove in a rotatable casting wheel, the mold normally included a crosssectional dimension ratio of approximately equal widthv and depth, which dimension ratio would permit a circular pouringspout to transfer the molten metal from thesupply source to the mold at a flow rate which would not create excessive turbulence in the mold.

In an advance development of the continuous casting system, the cross-sectional dimension ratio of the mold has changed such that the mold includes a major width and a" minor depth,- and in order to satisfy the molten metal requirement to "the wider mold, the flow rate through the circular pouring spout was increased. The

increased flow rate through the circular pouring spout also increased the turbulences developed in the molten metal at a point (such as point 34) adjacent an entrance 35 to the mold causing air bubbles to form in the molten metal which air bubbles frequently are carried with the molten metal as it is cooled and solidified into a cast bar, thereby detracting from the quality of the cast bar. Also, the same circular-spout-necessitated increased velocity flow rate has a tendency to cause bubble-generating undercurrents and voids in the metal in and aroundpoint 34 because increased turbulence results from the deeper solidification zone generated by said higher velocity flow rate-see, for example, the prior art solidification zone line 39 in FIG. 2 of U.S. Pat. No. 3,687,190 (Class 164-87).

When the molten metal is subsequently cooled and solidified, the bubbles appear as internal voids or surface blisters in the castbar. These voids and blisters weaken the bar so that when the bar is extracted from the casting wheel it is more likely to split or crack. When the cast bar passes to arolling mill, the blisters and voids may not be worked out of the metal as the metal is worked in the rolling mill and may pass with the metal as it is formed into a rod. Of course, these imperfections in the rod cause poor grain structure and form a weaker rod. As the rod is further processed into wire by drawing, the rod or wire is likely to break during the drawing process. 7 I

Eventually, the flow capacity of the pouring spout is reduced to a level that will not develop excessive turbulence, which levelis not sufficient'for proper operation of the casting machine; that is, the capacity of the pouring spout is not sufficient to maintain the pool of molten metal in the castingwheel. The operator then must reduce the rotational speed of the casting wheel to maintain the pool of molten metal, and this results in lower capacity casting.

SUMMARY OF THE INVENTION The above indicated disadvantages of the major width/minor depth .mold continuous casting system.

through the spout which substantially approaches the' flow rate of the molten metal moved by the mold; thus,

decreasing the turbulence developed in the mold and eliminating the air bubbles solidified in a cast bar formed by such a mold. a

One important feature of the present invention is the construction of a pouring spout which includes a discharge opening means having major and minor dimensions aligned with major and minor dimensions respectively, of the cross-sectional area of the'mold.

It is therefore a primary object of the present invention to proved a continuous casting system that eliminates voids and blisters from forming in the cast'jbar.

Another object of the present invention is to provide an improved pouring spout for use in a continuous casting system which permits the flow rate through the spout to substantially approach the rate of flow of molten metal moved .by a movable major width/minor providean improved pouring spout-for use in a continuous casting system which is simple in construction,

following description of the illustrative embodiments,

with reference to the accompanying drawings wherein like reference numerals have been used to refer to like parts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary side elevational view of a continuous casting system, with certain parts broken away and shown in section for purpose of clarity;

FIG. 2 is an enlarged sectional view taken along lines 2-2 of FIG. 1;

FIG. 3 is an enlarged sectional view taken along lines 33 of FIG. 1;

FIG. 4 is a fragmentary sectional view showing a second embodiment of an improved pouring spout;

FIG. 5 is a sectional view taken along lines 5-5 of FIG. 4;

FIG. 6 is an end elevational view as seen from the right of FIG. 4, showing the relationship of the spout discharge end within a major width/minor depth mold;

FIG. 7 is a sectional view taken along lines 7-7 of FIG. 8, showing a third embodiment of an improved pouring spout;

FIG. 8 is an end elevational view as seen from the right of FIG. 7, showing the relationship of the spout discharge end within a majorwidth/minor depth mold;

FIG. 9 is a sectional view taken along lines 9-9 of FIG. 10 showing a fourth embodiment of the improved pouring spout;

FIG. 10 is an endelevational view similar to FIGS. 6 and 8 showing the right end of the spout of FIG. 9; and,

FIG. 11 is a sectional view taken along lines 11-11 of FIG. 9.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS Referring now to the drawings, an improved pouring spout embodying the principles of the present invention will be described with reference to a continuous casting system 10, a portion of which is shown in FIG. 1, and includes a rotary casting wheel 11, flexible band 12, and molten metal supply source 14. Casting wheel 11, defines a peripheral groove 16, which is adapted to move into contact with flexible band 12, to form an open arcuate mold 18. Flexible band 12 is guided into contact with casting wheel 11, by a guide wheel 20, to form an entrance to the arcuate mold and is guided away from the peripheral groove 16 at a point (not shown) circumferentially. spaced along casting wheel 11.

As shown in FIG. 2, the arcuate mold, 18 is detailed in cross-sectional dimensions to include a major axis represented by line A and a minor axis represented by line B.

Molten metal is transferred from the supply source end 31, adapted to be connected in flow communication by conventional means (shown in FIG. 1) to the molten metal supply source 14. The pouring spout discharge end 32 is supported adjacent the entrance to arcuate mold 18, as shown in FIG. I. Pouring spout 30 includes a flow passageway 33, extending between the pouring spout entrance end 31, and the discharge end 32. The wall surface which defines the passageway extends substantially smoothly along the length of the passageway. The pouring spout entrance end 31, is substantially circular in cross-section and the discharge end 32, is substantially elliptical in cross-section to define a major axis C and a minor axis D. The pouring spout discharge end major and minor axes C and D are supported in substantial alignment with the arcuate mold major and minor axes A and B respectively, as shown in FIG. 2. The elliptical shape of the pouring spout discharge end will permit a maximum flow of molten metal through the discharge spout at a rate which approximately approaches the flow rate of molten metal moved by the arcuate mold. As the flow rate through the spout approaches the flowrate of the mold, said flow rate being controlled by a metering pin (not shown) associated with metal supply source 14, the turbulence developed in the mold adjacent the pouring spout discharge end will be substantially reduced thereby eliminating air bubbles in the mold.

As shown in FIG. 3, the passageway walls taper slightly inwardly as they approach the discharge end so as to present a cross-sectional area at the discharge end slightly smaller than the cross-sectional area along the remainder of the passageway. The slight reduction in the cross-sectional area of the passageway adjacent the discharge end of the pouring spout will ensure that the pouring spout passageway remains filled with molten metal during a transfer operation. Thus, the presence of voids and air pockets in the pouring spout which might otherwise be transferred to the mold are eliminated.

FIGS. 4-6 show a second embodiment of an'improved pouring spout embodying the principles of the present invention, with the second embodiment being generally represented by number 40. Pouring spout 40 includes a circular entrance end 41,. a rectangular shaped discharge end 42, and a-connecting flow. passageway 43. I

A third embodiment of the pouring spout is shown in FIGS. 7 and 8, and is generally represented by number 50. Pouring spout 50 'includes a circular entrance end (not shown, but similar to entrance ends 31 and 41 ll lustrated above) and a discharge end'52, which is constructed to include two individual

circular discharge passageways

53 and 54.

Passageways

53 and 54 aligned in an oval shell 59'having major and minor axes and therefore comprising a discharge opening means having major and minor axes which can be supported in alignment with the major A and minor B axes 'of the mold. The discharge passageways 53 and 54 are connected in flow communication with the spout circular entrance passageway 55, with thecombined crosssectional area of the two

passageways

53 and 54 being slightly less than the entrance passageway 55,-so as to eliminate voids and air pockets in the spout in a molten metal transfer operation. I

FIGS. 9-11 show a fourth embodiment of an improved pouring spout which is generally represented by number 60. Spout 60, includes a circular entrance end (not shown) and an entrance passageway 61, which is connected in flow communication with four

individual discharge passageways

62, 63, 64, and 65. The four discharge passageways are formed into an oval or wedgeshaped end 69 and are aligned to present major and minor axes of a cross-sectional discharge opening means, which major and minor axes are adapted to be supported in alignment with the major and minor axes of the mold.

OPERATION In operation, one of the improved pouring spouts embodying the principles of the present invention is connected to the molten metal supply source with the discharge end supported adjacent the entrance of the arcuate mold 18. Each of the above described embodiments includes discharge opening means having major and minor axes which are supported in substantial alignment with the molds major and minor axes, respectively.

In the operation of the continuous casting system, the casting wheel 11, and flexible band 12 are rotated in the direction of the arrows (FIG. 1) to form a moving arcuate mold, with the flow rate of the molten metal transferred through the spout adjusted to cause the mold to be filled until the pouring spout tip is submerged-this condition being referred to in the art as under-pouring. The speed of the casting wheel or the flow rate of molten metal moved by the mold is adjusted relative to the flow rate of the molten metal throughthe pouring spout so that the pouring spout tip remains submerged. Since the dimensions of the discharge opening means of the improved pouring spouts can, unlike prior art pouring spouts; be designed to permit a flow rate through the spout which approaches the flow rate required by the major width/minor depth mold, the turbulencein the mold adjacent the discharge end of the spout is substantially reduced, thereby eliminating voids and air bubbles from the molten metal and cast bar.

It now becomes apparent that each of the above described illustrated embodiments of an improved pouring spout embodying the principles of the present invention are capable of obtaining the above indicated objects and advantages. It is obvious that those skilled in the art may make modifications in the details of construction without departing from the spirit of the invention,

What is claimed is:

1. In an improved pouring spout for use in a continuous casting system having a movable casting mold defining a cross-sectional area which includes a major and a minor axis and includes a molten metal supply source, said improved pouring spout including an entrance end and a discharge end which are connected by a molten metal flow passageway, the entrance end being adapted to be connected in flow communication with said molten metal supply source and the discharge end being adapted to be supported adjacent an entrance of saidmovable mold, and wherein the discharge end of said pouring spout defines molten metal discharge opening means having major and minor axes of cross-sectional area aligned with said major and minor axes of said movable mold, said molten metal being transferrable from'said supply source through said pouring spout passageway to said movable mold at a flow rate approaching the flow rate of molten metal movedby said movable mold so as to substantially reduce the turbulence developed in said movable mold, each of said major axes being greater in length than its respective minor axis, and wherein said discharge end opening means includes an elliptical discharge opening defining said major and minor axes.

2. In an improved pouring spout for use in a continuous casting system having a movable casting mold defining a cross-sectional area which includes a major and a minor axis and includes a molten metal supply source, said improved pouring spout including an entrance end and a discharge end which are connected by a molten metal flow passageway, the entrance end being adapted to be connected in flow communication with said molten metal supply source and the discharge end being adapted to be supported adjacent an entrance of said movable mold, and wherein the discharge end of said pouring spout defines molten metal discharge opening means having major and minor axes of cross-sectional area aligned with said major and minor axes of said movable mold, said molten metal being transferrable from said supply source through said pouring spout passageway to said movable mold at a flow rate approaching the flow rate of molten metal moved by said movable mold so as to substantially reduce the turbulence developed in said movable mold, each of said major axes being greater in length than its respective minor axis, and wherein said discharge opening means includes a plurality of discharge openings aligned in oval shape to define said major and minor axes.

3. In an improved pouring spout as defined in claim 1, further characterized in that said pouring spout passageway is substantially circular in cross-sectional area adjacent said entrance end.

4. In an improved pouring spout as defined in claim 3, further characterized in that said passageway inmined cross-sectional area comprising, in combination:

a rotatable casting wheel defining a peripheral groove having a dinension ratio including a major. width and a minor depth;

an endless band covering a portion of said peripheral groove to form an arcuate mold having a crosssectional area which includes a major and a minor axis; I

molten metal supply means; and

a pouring spout operatively connected in flow communication between said supply means and said arcuate mold, said pouring. spout including a dis charge opening supported adjacent an entrance to said arcuate mold, said discharge opening including major and minor axes aligned with said mold major and minor axes,- molten metal being transferrable from said supply means to said arcuate mold at a flow rate which will substantially reduce the turbulence of molten metal in said mold, each of i said major axes being greater in length than its respective .minor axis, and wherein said discharge opening is formed to include at least two individual openings aligned into an oval configuration along said mold major axis.

6. In an improved'pouring spout as defined in claim 1, further characterized in that said pouring spout flow passageway is of slightly smaller cross-sectional area adjacent said discharge end than adjacent said entrance end.

7. In an improved pouring spout as defined in claim 2, further characterized in that said pouring spout passageway is divided into a plurality of passageways adjacent said discharge end, with the passageways being aligned in an oval combination corresponding to the oval shape of said discharge openings.

8. In an improved pouring spout as defined in claim 7, further characterized in that said number of divided passageways is two.

9. In an improved pouring spout as defined in claim 7, further characterized in that said number of passageways is four.

10. In a casting system for use in forming molten metal into a continuous length of material having a predetermined cross-sectional area comprising, in combination:

a rotatable casting wheel defining a peripheral groove having a dimension ratio including a major width and a minor depth;

an endless band covering a portion of said peripheral groove-to form an arcuate mold having a cross sectional area which includes a major and a minor axis;

molten metal supply means; and

a pouring spout operatively connected in flow communication between said supply means and said arcuate mold, said pouring spout including a discharge opening supported adjacent an entrance to said arcuate mold, said discharge opening including major and minor axes aligned with said mold major and minor axes, molten metal being transferrable from said supply means to said arcuate mold at a flow rate which will substantially reduce the turbulence of molten metal in said mold, each of said major axes being greater in length than its respective minor axis, and wherein said discharge opening includes an elliptical cross-sectional area defining said pouring spout major and minor axes.

said discharge openings.

Claims

1. In an improved pouring spout for use in a continuous casting system having a movable casting mold defining a cross-sectional area which includes a major and a minor axis and includes a molten metal supply source, said improved pouring spout including an entrance end and a discharge end which are connected by a molten metal flow passageway, the entrance end being adapted to be connected in flow communication with said molten metal supply source and the discharge end being adapted to be supported adjacent an entrance of said movable mold, and wherein the discharge end of said pouring spout defines molten metal discharge opening means having major and minor axes of crosssectional area aligned with said major and minor axes of said movable mold, said molten metal being transferrable from said supply source through said pouring spout passageway to said movable mold at a flow rate approaching the flow rate of molten metal moved by said movable mold so as to substantially reduce the turbulence developed in said movable mold, each of said major axes being greater in length than its respective minor axis, and wherein said discharge end opening means includes an elliptical discharge opening defining said major and minor axes.

4. In an improved pouring spout as defined in claim 3, further characterized in that said passageway includes a substantially smooth wall surface extending from said circular entrance opening to said elliptical discharge opening, with the cross-sectional area of said elliptical discharge opening being slightly smaller than said circular entranCe opening.

5. In a casting system for use in forming molten metal into a continuous length of material having a predetermined cross-sectional area comprising, in combination: a rotatable casting wheel defining a peripheral groove having a dinension ratio including a major width and a minor depth; an endless band covering a portion of said peripheral groove to form an arcuate mold having a cross-sectional area which includes a major and a minor axis; molten metal supply means; and a pouring spout operatively connected in flow communication between said supply means and said arcuate mold, said pouring spout including a discharge opening supported adjacent an entrance to said arcuate mold, said discharge opening including major and minor axes aligned with said mold major and minor axes, molten metal being transferrable from said supply means to said arcuate mold at a flow rate which will substantially reduce the turbulence of molten metal in said mold, each of said major axes being greater in length than its respective minor axis, and wherein said discharge opening is formed to include at least two individual openings aligned into an oval configuration along said mold major axis.

6. In an improved pouring spout as defined in claim 1, further characterized in that said pouring spout flow passageway is of slightly smaller cross-sectional area adjacent said discharge end than adjacent said entrance end.

10. In a casting system for use in forming molten metal into a continuous length of material having a predetermined cross-sectional area comprising, in combination: a rotatable casting wheel defining a peripheral groove having a dimension ratio including a major width and a minor depth; an endless band covering a portion of said peripheral groove to form an arcuate mold having a cross-sectional area which includes a major and a minor axis; molten metal supply means; and a pouring spout operatively connected in flow communication between said supply means and said arcuate mold, said pouring spout including a discharge opening supported adjacent an entrance to said arcuate mold, said discharge opening including major and minor axes aligned with said mold major and minor axes, molten metal being transferrable from said supply means to said arcuate mold at a flow rate which will substantially reduce the turbulence of molten metal in said mold, each of said major axes being greater in length than its respective minor axis, and wherein said discharge opening includes an elliptical cross-sectional area defining said pouring spout major and minor axes.

11. In a casting system as defined in claim 10, further characterized in that said pouring spout includes a substantially circular entrance opening, with said passageway having a substantially smooth wall surface extending from said circular entrance opening to said elliptical discharge opening.

12. In a casting system as defined in claim 5, further characterized in that said pouring spout passageway is divided into at least two individual passageways adjacent said discharge opening, with said passageways being aligned along said mold major axis in an oval configuration corresponding to the oval configuration of said discharge openings.