US3447590A - Roll type continuous casting apparatus - Google Patents

Description

June 3, 1969 E. A. OLSSON 3,447,590

ROLL TYPE CONTINUOUS CASTING APPARATUS Original Filed July 23, 1955 Sheet of 2 I5 [6 b E INVEIBTOR.

Erlk Allan lsscm. F 1g. 5 BY 6 F'ig.E.

Attorneys.

June 3, 1969 o sso 3,447,590

ROLL TYPE CONTINUOUS CASTING APPARATUS Original Filed July 25, 1965 Sheet 2 or 2 INVENTOR.

Erik Allan Olsso 72.

BY yvwwa, a., 1 ya,

Attorneys.

United States Patent Int. c1. B2211 11/06 US. Cl. 164277 7 Claims ABSTRACT OF THE DISCLOSURE This application relates to apparatus for continuous casting of metal by flowing the molten metal into a reservoir formed between the surfaces of two or more revolving rolls that turn toward each other. The molten metal, congealing on the surface of the rolls, is carried into a space between two rolls and emerges as a formed slab or strip. When the rolls are horizontal, there are end members at opposite ends of the rolls and cooperating with the roll surfaces to confine the molten metal, and when the rolls are vertical there is an end member only at the bottom. This application discloses tapering or sloping the surface of each end wall member that is contacted by the molten metal away from the path of flow of the metal so that the metal congealing on the surface of the rolls is continuously carried away and cannot become wedged under the end wall members.

This is a division of application Ser. No. 474,407, filed July 23, 1965, now abandoned, for Method of Manufacturing Products Directly From a Melt.

This invention relates to the continuous casting of metal by the use of at least two oppositely-rotating rolls in sideby-side relation, usually with their axes horizontal, and with a space between the rolls through which-formed metal emerges while molten metal is retained in a sump formed above and between the rolls, with fixed end walls to retain the molten metal from escape at the ends of the rolls.

Apparatus of the type to which this invention relates is well known, but a difliculty with such apparatus has arisen from the construction of the metal-retaining end walls. In the operation of the rolls, the metal congeals against the surface of the rolls and is carried by the rotation of the rolls toward a space between the rolls from which the formed slab or strip emerges. The metal layers so congealed form the opposite surfaces of the slab or strip emerging below the rolls. Since the end Walls forming the ends of the sump must have a working clearance with the rolls, congealed metal forms or works into the clearance between the roll and the end walls in the form of a thin fin or flash that becomes wedged between the end wall and roll to cause binding and galling that impedes the operation, disrupts formation of the edges of the emerging casting, and even destruction of the roll surface.

The present invention is for an improvement in apparatus of this type wherein the end wall or walls are so arranged in relation to the molten metal that metal is constantly carried away from the surface of the end wall and thereby prevents packing or jamming of the metal between the roll surface and the end wall. This is accomplished by so forming the surface of the end walls that they diverge away from the straight line direction in which the congealed metal is carried by the rotation of the rolls, so that as the molten metal flows against the face of the side wall where it confronts the roll surface and congeals, it is constantly pulled away from the clearance space between the end wall and the roll surface, and

the thin fin which has heretofore caused the trouble has no opportunity to form and become lodged under the end wall.

The invention is applicable not merely to an arrangement where there are only two horizontal rolls between which the formed metal passes, but to arrangements where there is a cluster of rolls arranged to form two slabs or strips moving in opposite directions, or where the rolls are vertical, in which case only one end wall at the bottom is needed.

In the drawings, which are largely schematic,

FIG. 1 is an end view of a casting apparatus embodying the invention;

FIG. 2 is a plan view of the apparatus shown in FIG. 1;

FIG. 3 is a fragmentary view of a larger scale showing a top plan view of the two rolls of FIG. 1 and the end wall structure;

FIG. 4 is a schematic section through a casting apparatus having a cluster of four rolls with two outlet passes for the simultaneous casting of two strips or slabs;

FIG. 5 is a fragmentary top plan view of one end of the cluster of rolls shown in FIG. 4;

FIG. 6 is a perspective view showing the end wall construction of FIGS. 4 and 5, apart from the rolls;

FIG. 7 is a top plan view, with the bearings removed, of a casting apparatus in which the axes of the rolls are vertical, and in which there is a cluster of four rolls also arranged to form two castings simultaneously; and

FIG. 8 is a fragmentary view in vertical section in the plane of line VIII-VIII of FIG. 7 showing the lower end of the apparatus of FIG. 7.

Referring first to FIGS. 1 to 3 of the drawings, it shows the general arrangement heretofore proposed of two horizontally-disposed rolls 1 side-by-side and spaced from each other as indicated at 5 to form a pass through which the formed slab or strip emerges. The space above and between the upper surfaces of the rolls provides a sump or reservoir for molten metal 2, and the metal is retained from escaping at the ends of the rolls by upright end walls 3 near opposite ends of the rolls 1 and contoured in the usual manner to conform to the surface of the rolls. A tundish arrangement for supplying molten metal to the reservoir in indicated at 2*. Various ways of supporting and holding the end walls in position are known in the art and have not been shown, but one arrangement adaptable to this invention is disclosed in US. Patent 2,128,941, granted Sept. 6-, 1938.

In the arrangement shown, the roll shafts 8 are supported in bearings 6 which are pressure-sensitive electrical transducers. The shafts 8 are geared together, as indicated by the gear box 7, for rotating the rolls in opposite directions so that their upper surfaces are moving toward the gap 5, as indicated by the arrows in FIG. 1. There is a variable speed drive or transmission 9 through which rotation of the motor 10 is imparted to the rolls, and the speed is controlled by an electrical control 11 responsive to the pressure of the roll shafts in the hearing 6, the schematic wiring 12 indicating such control arrangement.

As is usual in apparatus of this type, the rolls are watercooled, either by circulating water through them, or applying a water spray to the surface. For simplicity of illustration, this has been indicated by water sprays 13 in FIG. 2.

So much of the apparatus as has heretofore been described is generally known, except for the construction of the end walls 3. As most clearly seen in FIG. 3, those surfaces 3 of the end walls which are contacted by the molten metal, diverge from a plane transverse to the axes of rotation of the rolls toward the central area 2 of the end 'Walls. To state it differently, the surfaces 2 slope away from the straight line direction in which congealed metal on the surface of the rolls is carried around the surface of the rolls toward the gap 5. These surfaces are smooth and free of any projection to which the metal will congeal or otherwise be restrained from being freely pulled away from them as the metal congeals and moves toward the pass between the rolls.

Looking at FIG. 3, if the rolls were stationary, the hydrostatic pressure of the molten metal would tend to force a thin film of metal into the crevice between the roll confronting edges of the end walls and the rolls, and if the end wall faces were in a plane parallel with the straight line travel of the metal on the roll surface, such thin film would immediately congeal and form a wedge. The same would be true if the rolls were turning and the end walls were in such a parallel plane. However, with the end walls diverging from the straight line travel of the metal, or diverging in the direction of rotation of the rolls from a transverse plane through the rolls, the congealing metal is continuously carried away from the crevice. The curved portions of the flow arrows in FIG. 3 represent the molten metal flowing down and laterally against the end walls, and the straight portions of the arrows indicate the flow of congealed or congealing metal away from the crevice.

The remaining figures of the drawings indicate variations in the roll arrangement with a confining or end wall similarly angled away from a direction parallel with the straight line flow of the metal.

In FIGS. 4, 5 and 6, there is disclosed the adaptation of the invention to a casting apparatus comprising a cluster of four rolls; the upper two designated 14 are spaced from each other and spaced to a lesser extent from the lower two, designated 15, and the two rolls 15 are in contact with each other. Driving means, not shown, but which may be generally similar to that shown in FIG. 2, rotates each of the two diagonally-opposed rolls in the same direction and opposite the other two, as indicated by the arrows. There are opposed end walls 16. The arrangement provides oppositely-extending forming passes or gaps 17 for the simultaneous formation of opposite laterallymoving strips or slabs 18. To this end the confronting surfaces of the upper two rolls revolve toward each other, and the confronting contacting surfaces of the lower two rolls turn opposite each other.

The end walls 16 in this arrangement are in metalconfining relation with the top two rolls through an arc of nearly 180 and the walls adjacent the rolls diverge in the manner heretofore described with reference to the fiow of metal. The end wall structure so formed continuously decreases in thickness in the roll-conforming areas from the top through the extensions 16 that extend into and terminate in the metal-forming passes at each side, and then increases in thickness downwardly in the area 16 that fits into the space between the two lower rolls. This change of thickness occurs because of the formation of the metal-retaining surface of the end wall. The shape of the outer face is unimportant, but for simplicity of description, is here shown as being planar, in contrast to the compound slope of the inner face.

Referring now to FIGS. 7 and 8, there is also shown a cluster of rolls arranged in two pairs, those of one pair being designated 20, and those of the other pair 21. These rolls, however, have vertical axes, and the two pairs are spaced from each other to form two gaps or outlets 22 for the formed castings, these being opposite each other. The rolls of each pair contact each other, and as in previous arrangements, all rolls rotate at the same speed with the rolls of each pair being driven in a direction opposite the direction of the other roll of each pair, as indicated by the arrows. Also rolls between which the forming opening is provided rotate, as in FIG. 4, in 0pposite directions. Thus the surfaces of left-hand rolls 20 and 21 have their confronting surfaces moving in a direction to force metal out between them, and similarly the confronting surfaces of the right two rolls move in a direction to move metal out the gap at the right.

This arrangement requires an end plate 23 only at the lower end of the roll cluster, since the metal is poured into the central cavity 24 at the top, and the formed strips or slabs emerge in a vertical plane. The top face of this end plate slopes in opposite directions from the center outwardly and downwardly in opposite directions, so that here, as in the preceding apparatus, the end plate has surfaces which diverge from the direction of straight-line flow of the metal, or which diverge from the central area outwardly relative to a plane passing transversely through the rolls. This is best seen in FIG. 8 where the surfaces 23 contoured to fit about the rolls slope in the abovedescribed direction and terminate in the metal-forming passes 22 In all embodiments here described, the end wall or end walls which contact the metal are smooth and free of any obstruction or irregularity that would impede the flow of metal away from said surfaces, and diverge from the straight line travel of the metal into the forming opening or openings from which the casting emerges. In FIGS. 1 to 4 where there are only two rolls defining a single pass, the slope is from the distal edges of the end wall toward the central area, this being divergent to the straight line flow of metal into the pass, and in FIG. 5 the angularity reverses from the top to the two discharge passes near the bottom, although the slope with reference to the straight line flow is continuous, and in FIGS. 7 and 8 the slope is away from the center toward the distal edges, which is opposite FIG. 4, but functionally the same. In each case the end wall has a central area with at least two oppositelydirected portions, each contoured to fit about one of two rolls that provide between them a casting forming pass, and each such portion extends into the pass through which the formed casting emerges. The faces of the end wall against which the molten metal is confined to retain a pool or sump of the molten metal between the two or more rolls, as the case may be, angle outwardly toward the roll ends toward the pass, that is, angle away from a straight-line flow of the congealed metal on the roll surface into the pass, the width of the pool in the direction of the length of the rolls increasing toward the forming pass. In this manner congealing metal is always carried away from the end wall where the edges of the end 'wall confront the roll surfaces.

I claim:

1. Casting apparatus comprising at least two confronting rolls in spaced relation defining a molten metal holding space between them and with a forming pass through which the formed casting emerges, and an end wall adjacent an end of the rolls arranged to retain molten metal in said space with edges contoured to conform to the surfaces of the two rolls and with a working clearance with the rolls, said end wall having that face which contacts the molten metal being smooth and free of irregularities and angled throughout its length with respect to the axes of the rolls in such manner that said metal-forming space increases in width in the direction of the length of the rolls toward the forming pass between the rolls, and means for rotating the rolls oppositely to each other in a direction to carry metal that congeals on the surfaces thereof into the forming pass.

2. Casting apparatus comprising at least two confronting rolls in spaced relation defining a molten metal holding space between them and with a forming pass through which the formed casting emerges, and an end wall adjacent an end of the rolls arranged to retain molten metal in said space having portions which extend from said pass in opposite directions, one over the surface of one roll and one over the surface of the other, each with edges that conform to the curvature of the roll surface over which it extends and with which it has a working clearance, each such portion throughout its entire length being angled from the pass toward the mid transverse plane of the rollers so that they diverge with respect to a straight line flow of metal from said space into the forming pass in such manner that metal that congeals on the roll surfaces immediately adjacent said end wall portions is carried by rotation of the rolls away from the end walls and so prevented from becoming wedged under the end walls.

3. Casting apparatus as defined in claim 2 in which there are two horizontal rolls in side-by-side relation, and the casting forming pass is between them with the metal holding space being between the upper portions of the rolls above the forming pass, one of said end walls being located adjacent each end of the two rolls, each end wall having a face portion thereof that contacts the molten metal and which is above that one of the two rolls about which said portion is contoured, and so diverge from a plane passing transversely through the rolls.

4. Casting apparatus as defined in claim 2 in which there is a cluster of four rolls with their axes horizontal and with two rolls spaced above the other two rolls to provide a single metal holding space and two opposite laterallyopening forming passes, there being two end plates, one adjacent each end of the rolls, each having the edges thereof contoured to fit about and have working clearance with each of the four rolls, the confronting faces of the two end members being smooth and are so angled with respect to the roll axes that the distance between them increases toward said laterally-opening roll passes.

5. Casting apparatus as defined in claim 2 in which there is a cluster of four rolls arranged with their axes vertical and providing at the center of the cluster a molten metal holding space, the rolls of the cluster being arranged in two pairs, one pair being spaced from the other to form two opposed forming passes leading from said central space, the rolls of each pair being in contact with each other and being driven in opposite directions, there being a single end wall adjacent the lower end of the roll cluster having the edges thereof contoured to extend around a portion of the periphery of each of the rolls with the contoured edges of the end wall member having a working clearance with the roll surfaces, the top face of the end wall being smooth and being so angled with respect to a plane passing transversely through the rolls that they diverge away from said plane in the direction of said two forming passes in such a manner that metal congealing on the surfaces of the rolls forming each of the two forming passes is carried by rotation of the rolls away from said edges of the end walls toward the forming pass provided in part by that roll on which it congeals.

6. Apparatus for producing solidified metal products directly from molten metal wherein the molten metal is introduced between rotating rolls and solidified metal is fed out from between the rolls, the combination comprising:

(a) a plurality of rotatable rolls mounted in adjacent and cooperating positions to form a metal holding sump with a casting forming pass leading therefrom between the rolls,

(b) at least one confining wall for confining molten metal between it and the rolls to thereby form a sump for molten metal, the confining wall having its edges shaped to conform to the curvation of the rolls with the edges providing a working clearance with the surface of each roll and having the face which is toward the sump smooth and angled away from a transverse plane through the rolls toward the forming pass in such a manner that molten metal congealing on the rolls adjacent the conforming edges of the end walls is carried by rotation of the rolls away from said edges, and

(c) means for rotating the rolls in opposite directions with the surfaces thereof moving in a direction toward said forming pass.

7. Apparatus according to claim 6 wherein there are two rotatable rolls in side-by-side relation with their axes horizontal and a confining wall is positioned adajcent each end of the two rolls for confining molten metal at each end of the rolls, the distance between the end walls increasing in the direction of the forming pass in such a manner that metal congealing on the rolls is carried by rotating the rolls from the sump into the roll pass.

References Cited UNITED STATES PATENTS 2,790,216 4/1957 Hunter 164-88 49,053 7/1865 Bessemer 16487 1,704,580 3/1929 Showers -253 X 1,756,196 4/ 1930 Hopkins et a1. 164-87 1,903,897 4/ 1933 Harris 164-277 2,108,753 2/1938 Low 164-87 2,183,010 12/1939 Coxe 164-87 3,038,219 6/1962 Hudson 164-88 I. SPENCER OVERHOLZER, Primary Examiner. R. SPENCER ANNEAR, Assistant Examiner.

US. Cl. X.R. 65-253

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