FR2505691A1 - Curving continuously cast metal bar - from a vertical mould to the horizontal - Google Patents

Abstract

A continuously cast metal bar, from a vertical mould, is turned towards the horizontal, through a circular arc, by a guide roller assembly. It is then progressively straightened, and passed through a set of extractor rollers at right angles to its original direction. These are offset below the standard position of a parallel tangent produced from the continuation of the circular arc. In the straightening zone there are no guide rollers, but pairs of support rollers, separated by the thickness of the bar. These float radially on slides, and each pair may be mounted between two hydraulic jacks. By allowing the rollers in the straightening zone to float, the bar follows a natural path, and loading on the rollers and their supports, and hence wear and maintainance, is reduced compared with known practice where the rollers guide as well as support.

Description

 The present invention relates to the continuous casting of metals, and more particularly the straightening of a continuous casting bar, between the outlet of a guiding corset in an arc of a circle and a horizontal corset, for example a corset of extractor rollers.

 According to a conventional solution, a continuous casting bar is guided along a path in an arc of a circle extended by a rectilinear path, generally horizontal, tangent to said arc of circle.

Other known straightening devices provide a path comprising several sections, each having a constant radius of curvature, said radius of curvature having an increasing value from one section to the next. I1 therefore exists along the straightening path a plurality of radii of curvature materialized by straightening points at which guide rollers are provided.
The position of each of these rollers is fixed.

 Experience shows that the wear of the rollers causes displacement of the straightening points and if one wants to maintain these points in their theoretical positions the maintenance of the rollers becomes very expensive.

 The object of the present invention is to avoid such a drawback.

 It consists in providing an arrangement according to which there are no longer any straightening geometric points, the bar passing naturally, that is to say with minimal constraints, from the curved shape to the straight shape. This amounts to letting the bar follow a path of least resistance, the radius of curvature of which increases continuously.

 A more specific subject of the invention is a curved continuous casting installation comprising an ingot mold, a roller guide corset of a casting bar following an arcuate path, and a rectilinear roller corset, characterized in that said corsets are separated by a progressive straightening zone of the bar, said zone being devoid of guide rollers, and in that the rectilinear corset is offset downward relative to the conventional position defined by the tangent to the extension of the arcuate path of circle parallel to the direction of the rectilinear corset.

 The straightening zone may comprise a plurality of pairs of holding rollers, the rollers of each pair being spaced apart by a distance corresponding to the thickness of the bar, and each pair of rollers being mounted floating in a substantially radial direction, so to follow the position of the bar during its deformation.

 Each pair of holding rollers is movably mounted on slides.

 Each pair of holding rollers can be mounted between two cylinders.

 The invention will be better understood by referring to the description which follows, given with reference to the appended drawings, relating to two embodiments given by way of nonlimiting examples.

 Figure 1 is an overview of a continuous casting installation according to the invention.

 Figure 2 is an enlarged detail view of Figure 1 showing a pair of rollers with its slides.

 Figure 3 is also a detail view on a larger scale of a pair of rollers mounted between two cylinders.

 In FIG. 1, the reference numeral 1 designates an ingot mold at the outlet of which is fitted a guide corset 2 of a casting bar 3. The corset 2 comprises three sections, each section consisting of a plurality of pairs of rollers 4. These rollers guide the bar along a path in an arc of a radius R. At the exit from the corset 2, there is a straightening zone for the bar which will be discussed more explicitly below. Following the straightening zone, a horizontal corset 5 is provided, for example, a corset of extractor rollers 6.

 Within the straightening zone defined by the interval between the corsets 2 and 5, pairs of holding rollers such as 7 are mounted.

The spacing of the rollers 7 of each pair is equal to the thickness of the bar. Each pair of rollers 7 is mounted independently of one another between uprights 8 resting on a support structure 9. The rollers 7 are provided to take up the ferrostatic pressure of the bar 3 which is not fully solidified. The pairs of rollers 7 are mounted floating in the radial direction in order to follow the position of the bar 3 during its deformation. The rollers 7 are not guide rollers because they do not require the bar 3 to follow a determined path.

 The theoretical profile 10 of the bar 3 is shown in hatched lines in the case where, in the absence of continuous straightening, said bar would follow an entire path in an arc of a circle, practically in a quarter circle extended at its lower end. by a horizontal straight line tangent to the said quarter circle. Mark A illustrates the downward shift between the path with continuous straightening and the conventional path.

 According to a first exemplary embodiment, the angular extent o (of the straightening zone is 15. The length of the bar 3 in said zone is 800. And the offset A is 4 mm.

 According to a second embodiment, for the same angular extent of the straightening zone, the length of the bar 3 in said zone is 2500, and the offset A of 15 mm.

 As shown in FIG. 2, a pair of holding rollers 7 is mounted movable in the radial direction along slides 11 integral with the uprights 8.

Each roller 7 is mounted on a chock, such as 13, and the chocks are separated by shims 14 which regulate the spacing of said rolls so that this spacing corresponds to the thickness of the bar 3. The chocks 13 are made integral with one another by conventional means. The lateral faces of the chocks 13 can move along the runners ll to allow the holding rollers 7 to follow the position of the bar 3.

 According to the variant illustrated in Figure 3, the radial mobility of each pair of rollers 7 is provided by two cylinders, such as 12, mounted in opposition.

The cylinders 12 hold the rollers 7 in position, but allow a radial displacement of the pair of rollers 7 when the force exerted on a roller 7 is greater than the pressure exerted by one or the other of the cylinders 12. Each cylinder is mounted between the adjacent uprights 8. The rod of each jack is coupled to the chock 13 of a roller 7. The reperde 14 designates the spacers of the chocks 13.

 The cylinders 12 are kept permanently under pressure, from an oleo-pneumatic accwiulator for example.

 Although the invention has been described with reference to two strong particular embodiments, it goes without saying that it is in no way limited thereto and that modifications may be made to it without departing from its field.

 We can, at the limit, remove the pairs of holding rollers 7 and leave the bar 2 completely free between the output of the corset 2 and the input of the corset 5.

 We can of course replace any of the means described by a technically equivalent means.

The invention therefore covers, in addition to the examples shown, their different variant embodiments.

Claims (4)

1. Curved continuous casting installation including  an ingot mold (1), a guiding corset (2) to  rollers (4) of a bar (3) poured along a path  in an arc, and a straight corset (5) with  rollers (6), characterized in that said corsets  are separated by a phase-out zone of  the bar (3), said zone being devoid of rollers  guide, and in that the rectilinear corset (5) is  shifted down from the classic position  defined by the tangent to the extension of the path in  arc of a circle parallel to the direction of the corset  straight (5). 2. Installation according to claim 1, characterized  in that the righting area includes a plurali  t of pairs of holding rollers (7), the rollers  of each pair being separated by a corresponding distance  depending on the thickness of the bar (3), and each pair  of rollers being mounted floating in a direction  substantially radial, in order to follow the position of  the bar (3) during its deformation. 3. Installation according to claim 2, characterized  in that each pair of holding rollers (7) is  movable mounted on slides (11). 4. Installation according to claim 2, characterized  in that each pair of holding rollers (7) is  mounted between two cylinders (12).