US3370642A

US3370642A - Strand guide for a continuous casting plant

Info

Publication number: US3370642A
Application number: US476865A
Authority: US
Inventors: Meier Walter; Thalmann Armin
Original assignee: Concast AG
Current assignee: SMS Concast AG
Priority date: 1964-08-04
Filing date: 1965-08-03
Publication date: 1968-02-27
Anticipated expiration: 1985-02-27
Also published as: GB1112832A; US3496990A; CH414957A; FR1443678A

Description

Feb. 27, 1968 w, EI ETAL 3,370,642

STRAND GUIDE FOR A CONTINUOUS CASTING PLANT Filed Aug. 5, 1965 2 Sheets-Sheet l a N u) N I N VEN TORS A BY ATTORNEYS Feb. 27, 1968 w. MEIER ETAL 3,370,642

7 STRAND GUIDE FOR A CONTINUOUS CASTING PLANT 2 Sheets-Sheet 2 Filed Aug. 5, 1965 ATTORNEYS United States Patent 0 f STRAND GUIDE FOR A CONTINUOUS CASTING PLANT Walter Meier, Winterthur, and Armin Thalmann, Zurich, Switzerland, assignors to Concast AG., Zurich, Switzerland Fiied Aug. 3, 1965, Ser. No. 476,865 Claims priority, application Switzerland, Aug. 4, 1964, 10,173/ 64 1 Claim. (Cl. 164282) ABSTRACT OF THE DISCLOSURE The strand guide system comprises a roller guide positioned below a continuous casting mold. The roller guide consists of a roller guide mounting means positioned adjacent the desired course of the strand and includes a plurality of guide roll pairs. Each of the roll pairs consists of a first and second roller spaced apart by a predetermined fixed distance and so mounted as to permit a limited deflection of each of the roller pairs in a direction transverse to the longitudinal axis of the strand. By this means, proper guidance is achieved in a guide arrangement requiring less set-up time.

The present invention relates to an apparatus for continuous casting of metal and particularly refers to an apparatus for guiding the cast strand immediately below the mold.

In most cases a strand guide system of this kind comprises guiding elements in the form of rollers. These strand guide systems are known as roller guide systems and consist of a number of successive pairs of rollers, the rollers of each individual pair being disposed one opposite the other with fixed spacing between them. The sum of the distances between the individual pairs of rollers gives the guide path for the strand withdrawn from the mold, such strand being preceded by a dummy bar.

Of course, this dummy bar and the following cast strand can be satisfactorily introduced, guided and delivered only if casting is preceded by accurate setting up of the various pairs of rolls in relation to one another allowed by setting up of the entire roller guide system with respect to the mold aperture and the rolls situated downstream thereof (for example the withdrawing rolls, bending or straightening rolls).

This setting up operation is very time-consuming particularly when curved strands are being cast from a curved mold. Any mistakes made during setting up may have a disastrous effect on casting, since rolers which have not been set up accurately may cause the strand to break because of their forces exerted on the strand or may at least result in non-uniform strand quality.

The strand guide system according to the invention obviates these disadvantages, to which end it comprises curved strand guiding means consisting of pairs of rollers where each pair is movable to a limited degree perpendicular to the surface of the strand S and centers of rollers are firmly interconnected by maintaining a fixed distance between each other.

In this way, for example, on introduction of the dummy bar self-alignment of the movable roller pairs is obtained so that exact setting up of the roller guide system is dispensed with. During casting, the strand and the guide system adjust to one another flexibly so that any extreme or abrupt stresses on eitheri.e. either the strand surface or the rollersare obviated and the strand is guided gently but firmly along and to the end of the guide system.

3,379,642 Patented Feb. 27, 1968 Further characteristics of the invention can be seen below.

Two exemplified embodiments of strand guide systems according to the invention are illustrated in the accompanying drawings, wherein:

FIG. 1 is an elevation view of a continuous casting plant using the strand guide in accordance with the present invention.

FIG. 2 is an elevation view of a portion of the strand guide of FIG. 1 to enlarged scale.

FIG. 3 is a section on the line IIIIII in FIG. 1.

FIG. 4 is a section on the line IV-IV in FIG. 1.

FIG. 5 is a section of the movable pair of rollers on the line V-V in FIG. 6, as a detail of a roller guide according to a second embodiment, and

FIG. 6 is an axial section on the line VIVI through the movable pair of rollers of the second embodiment shown in FIG. 5.

As shown in FIG. 1, liquid metal is poured from a container not shown in accompanying drawings, into a cooled mold K. This mold K is closed by a dummy bar at its withdrawal end, reaching down to a withdrawing and straightening aggregate A. The resulting strand S is drawn from the mold K, when the solidified skin is of sufficient strength, guided by curved strand guiding means positioned between mold K and aggregate A and cooled fur ther as already known.

The roller gmide system illustrated consists of three parts 2, 3, 4 (alternatively they could be just two or more than three), each consisting of interconnected top and bottom angle-section pairs 5 and 6 respectively. The detachable connection between the adjacent roller guide system elements is by way of stays 7 and 8 which are affixed to the top and to the bottom angle sections 5 and 6 of two adjacent parts. Another two such stays 9 and 10 are also provided at the free ends of the roller guide system parts 2 and 4. The same arrangement is provided on the other side of the rollers (see FIG. 4) at a distance corresponding to the width of the roller guide system.

Bearings to receive the journals of rotatably mounted rollers 11, 12 are provided in the stay 9; for rollers 13, 14 in stay 8; for

rollers

15, 16 in stay 7; and for rollers 17, 18 in stay 10. Thus, the stay mounted rollers are fixedly positioned in a predetermined distance apart.

Other pairs of rollers, for example the

rollers

19 and 20, are provided between these fixed pairs of rollers, but are movable to a limited extent in a direction at rightangles to the strand axis while firm interconnection is maintained between them. In the exemplified embodiment shown in FIGS. 1 to 3 this is achieved by the fact that the journals of the rollers 1? on the surface forming the inner radius of the strand, and of the rollers 20 on the surface forming the outer radius of the strand are the pivot axes of

link chains

21 and 22, the

rollers

11, 13, 15, 17, 19 of the pairs all being situated between the inner two chains 21 and the

rollers

12, 14, 16, 18, 2%) all being situated between the two outer chains 22. The

chains

21, 22 respectively hang freely between the

fixed rollers

11, 13, 15, 17; 12, 14, 16, 18 respectively, the outer chain 22 in each case extending in parallel relationship to the inner chain 21 on the same side of the strand S. The firm distance between the two

link chains

21, 22 at each end of the rollers and hence the firm distance between the

rollers

19, 20 of each movable pair is achieved by shackles 23 connecting the pivots of the rollers -19, 20 forming a pair. Of course, this distance is equal to the distance between the rollers of the fixed, i.e. non-slidable, pairs of rollers. While this fixed distance between the

rollers

19, 20, which depends on the strand cross-section, is maintained, the pairs of rollers are movable independently to a limited extent in a direction at right-angles to the strand axis between the immovable pairs of rollers mounted on the stays 7 to 10.

The same effect is obtained with the embodiment shown in FIGS. 5 and 6 but without the use of chains. The roller guide system in this embodiment comprises rails 32 to support the consecutive pairs of

rollers

30, 31, such rails being disposed on each side of the rollers and the longitudinal axis of the rails corresponding to the imaginary strand axis. As in the first exemplified embodiment, the two

rollers

30, 31 of each movable pair are kept at a fixed distance according to the strand size by means of shackles 33 at the ends. Between the

rollers

30, 31 each of these two-part shackles 33 extends through a boss 34 secured to the rail 32, so that they and the associated

rollers

30, 31 are slidable at right-angles to the axis of the strand S at this place between a top and bottom end position. Springs 35, 36 disposed on each side of the boss 34 in the direction of displacement between the latterand a shoulder of the shackle 33 ensure that the

rollers

30, 31 are always kept in a middle position between the two end positions, but being displaceable independent of neighbouring pairs of rollers vertical to the strand surface between two end positions against springs with respect to a fixed rail.

Advantageously, in the two embodiments described, the slidability of the movable pairs of rollers from the middleposition in each direction is about 1 to 2".

All the fixed pairs of rollers could be driven in the manner already known, so that they could completely or partly act as withdrawing rollers.

Instead of rollers, the guide elements used may be in the form of sliding elements movable vertically in relation to the strand surface.

The continuous casting machine in FIG. 1 shows a curved mold to be used to a cast curved strand. By having a mold which is straight relative to the axis of the strand casting a straight strand, several consecutively and firmly mounted pairs of rollers 11, 12 have to be disposed to take up the forces arising from bending of the strand at the beginning of the curved strand guiding means -1.

To simplify accompanying drawings, the guiding means were confined to two faces (the upper and lower in FIG. 1) of the strand, whereas in certain cases it would be essential to have several consecutively mounted guiding rollers arranged on the other faces as well.

What is claimed is: V

1. An improved strand guide for a continuous casting plant in which liquid metal is poured into a cooled mold to solidify the periphery of said metal into a skin enclosing a molten core and defining a strand which is withdrawn continuously from said mold and is further cooled after it is withdrawn from the mold, which comprises roller guide mounting means positioned below the mold to receive the strand as it is withdrawn from the mold, at least three roller pairs fixedly mounted on said roller guide mounting means, the first of said fixedly mounte roller pairs being positioned at the entrance to said mounting means, the second being positioned at the exit end of said mounting means, and the third being positioned intermediate the entrance and exit of said mounting means, a plurality of deflectable guide roller pairs, each of said roller pairs comprising a first and second roller spaced apart by a predetermined fixed distance, a link coupling together said first and second spaced apart roller of each pair, a plurality of links coupling together a roller in each of said roller pairs with the corresponding roller of each adjacent roller pair, said links being pivotally connected to each of said rollers to form a chain link interconnecting said defiectable roller pairs, and links coupling the last of said chain of defiectable roller pairs to the respective rollers of the adjacent fixed roller pair, thereby to support said deflectable roller pairs and to provide a guide for guidance of said strand in which the respective defiectable roller pairs can deflect to a limited degree transversely to the longitudinal axis of said strand.

References Cited J. SPENCER OVERHOLSER, Primaly Examiner.

o R. S. ANNEAR, Assistant Examiner.