Impact pad for continuous casting

Abstract: The impact pad for continuous casting is foreseen for being collocated in the floor of a refractory tundish which receives the molten metal coming from a pouring ladle, and is constituted by a boxlike hollow body (1) the floor (5) of which is wavy in shape, and a mouth (2) of less width than its base (1). The impact pad, which is able to have a rectangular, trapezoidal, triangular and even circular outline, avoids all kinds of turbulence on the exterior thanks to the step (4) which is formed by the internal side walls (3) and the mouth (2).

Description: OBJECT OF THE INVENTION The present invention relates to an impact pad for continuous casting, foreseen to be located on the floor of a refractory tundish which receives from a ladle the molten metal which has to pass from the aforementioned tundish to the pertinent mould, such that the impact pad constitutes a species of box with an opening on the top for the entry of the molten metal which is poured from the ladle, all of this in order to achieve an adequate orientation of the flow of molten metal, and also to avoid turbulence and splashing which normally give rise to a series of problems and drawbacks when said turbulence and splashing impact against the flow that is poured into the box that constitutes the pad. The invention solves this problem by an impact pad having the features of claim 1. Optional features of the pad are set out in claims 2-5. The invention thus provides a new type of impact pad for continuous casting which as well as having the form of a box has its floor wavy or grooved in order to achieve results better than those obtained by means of the known impact plates or boxes. BACKGROUND OF THE INVENTION It is well known that the molten metal which is poured into the forming moulds comes from a refractory tundish which is situated between the pertinent ladle supplier of the molten metal and the forming mould itself. Logically if the outflow from the ladle to the tundish is made directly onto the flat floor many problems are thereby originated, such as a rapid displacement of the molten metal over the floor and impact against the side walls of the tundish, producing turbulence which gives rise to many problems and inconveniences that need not be mentioned here. In an endeavour, to overcome the problems and inconveniences arising from direct pouring from ladle to tundish, in European Patents with application number 94931389.4 and 95934731.1, respective damping impact platforms to prevent the turbulence are described for continuous casting, which platforms come in the form of a box, in one case with concave internal walls with the mouth on top strangulated with respect to the actual floor of the box which constitutes the damping impact platform, whilst in the second case said platform has its internal wall with straight steps which minimise the turbulence created. In these two European Patents, the floor of the damping platform is completely flat, which prevents an adequate orientation of the flow of molten metal which is poured thereupon, and also leads to a notable erosion in the floor of the box that constitutes the platform, precisely as a consequence of the flatness of the floor. The North American patent 5,188,796 can also be mentioned, in which is described a tundish with a wavy damping impact platform, although in this case said damping platform is a piece independent of the tundish, with the problems and inconveniences arising therefrom, as well as occupying a zone off-centre from such tundish which originates a lack of orientation in the flow of molten metal, at times requiring supplementary elements such as weirs in order to be able to achieve a certain orientation of the resulting flow, in the desired direction of interest. Hence, whilst in the two abovementioned European Patents the damping impact platform has the form of a box, but with its floor flat, with the aforementioned inconveniences and problems, in the North American Patent, though having a wavy platform, this constitutes a flat piece independent of the tundish, as well as not being duly designed in its placement with the aim of achieving optimum results in the pouring and orientation of the flow. GB-A-754 573 discloses a box insert resting on the bottom of an ingot mould, which insert has concentric upright side walls and a bottom having wave-like projections. The upper ends of the side walls are straight and not stepped and define a mouth of same size as the bottom. DESCRIPTION OF THE INVENTION The impact pad for continuous casting which is proposed, being foreseen for collocating on the floor of a conventional refractory tundish, presents the particularity of combining in a single unit the boxlike configuration and the corresponding wavy floor, that on one hand eliminates the problems and inconveniences found in the damping impact boxes for continuous casting having a flat floor, and on the other hand, those found with wavy plates but which are independent and flat elements that are not boxlike. More specifically the impact pad object of the invention is constituted by a boxlike body with any appropriate configuration, be this rectangular, trapezoidal, triangular and even circular, wherein the width of the floor has to be greater than the width of the mouth, and the latter also to be provided with a step with respect to the internal side surface, for the purpose of determining a means for reorienting the flow toward the exit, avoiding turbulence and other problems. Moreover, the box-shaped body has its floor wavy, wherein the wave can have the length the same as or different to its amplitude, or else the wave can be in form of a "V", or the floor can even be grooved, in such a manner that in whatever case, regardless of the configuration of the pad, and the disposition or form of the undulations, the benefits that are obtained with respect to the traditional systems, including those of the two European patents and the North American patent mentioned in the previous section, can be summarised as follows: The direction of the wave or groove foreseen in the floor of the impact pad, orients the flow of the molten metal inside the actual box which constitutes the pad. The special configuration of the box in combination with the undulation or grooves in the floor, prevents the problems of erosion in said floor. The wavy or grooved configuration of the floor originates a diminution of the impact surface, with the advantage of being able to make use of more economical refractory materials. Depending on the design of the tundish the resulting flow of molten metal can be oriented in the direction of interest, thereby avoiding the use of supplementary directing means such as sidewalls and weirs, required and necessary in other traditional systems. DESCRIPTION OF THE DRAWINGS To complete the description being made and to assist in a better understanding of the characteristics of the invention, according to a preferred example of practical embodiment thereof, as an integral part of said description, a set of drawings is attached in which by way of illustration and not restrictively, the following is shown: Figure 1.- Shows a plan view of an impact pad for continuous casting implemented in accordance with the purpose of the invention. Said pad is quadrangular in outline and its floor is wavy. Figure 2.- Shows a cross-sectional view on the plane corresponding to the line A-A' represented in the previous figure. Figure 3.- Shows a plan view of an impact pad in which the outline is circular and the floor is based on concentric undulations. Figure 4.- Shows a cross-sectional view corresponding to the line B-B' represented in the previous figure. Figure 5.- Shows a plan representation of an impact pad in this case with a triangular configuration and grooved floor. Figure 6.- Shows a cross-sectional view corresponding to the line C-C' represented in the previous figure. PREFERRED EMBODIMENT OF THE INVENTION As may be seen from the referenced figures, and in relation specifically with figures 1 and 2, the impact pad for continuous casting of the invention is made up of a boxlike body (1), the mouth (2) of which is of notably smaller width than the actual base or floor of the body (1) or box which constitutes the impact pad itself. As may be seen in figures 1 and 2, said impact pad (1) is quadrangular in outline, the internal surface of its side wall (3) being upwardly convergent, until a step (4) is reached which determines not only a smaller width of the mouth (2) with respect to the floor (5) of the box or pad (1), but also an obtuse dihedron which shall determine the flow of molten metal which is poured into the box that constitutes this impact pad (1), before reaching the exit and in its displacement over the internal surface of the side wall (3), instead of exiting directly through the mouth (2) it impacts against this step (4) avoiding any type of turbulence in the outward direction. The pad (1) mentioned has its floor (5) wavy, which orients the flow of molten metal poured from the ladle toward the interior of said boxlike impact pad (1). In a variant of embodiment, shown in figures 3 and 4, the pad (1') is circular in shape and the undulations of the floor (5') concentric, having in this case the internal side surface of its side wall (3') straight, in which the step (4') forms a right angle with that internal side surface of the side wall (3') of the boxlike pad (1). The mouth (2') of the pad (1') is in this case circular, as illustrated in figure 3. In the variant of embodiment illustrated in figures 5 and 6, the pad (1'') is triangular in outline, with the pertinent mouth (2'') having the same shape, the internal surface of the side wall (3'') is straight, determining that the step (4'') forms a right angle with that internal surface of the side wall (3''). In this case, grooves have been implemented in the floor (5"), which are also wavy in profile, with the same function and purpose as those provided for the forms of embodiment illustrated in the figures 1-2 and 3-4. The impact pad is formed by a species of closed box with it mouth of less width than the floor, and being able to adopt whatever geometry, be this rectangular, trapezoidal, triangular and even circular, and its floor wavy or grooved.

Claims: Impact pad for continuous casting, which is foreseen for being collocated in the interior of a tundish which receives the molten metal coming from a pouring ladle, and from which tundish said molten metal is channelled to a forming mould, the impact pad being constituted by a hollow boxlike body (1) having whatever geometric configuration, a wavy or grooved floor (5) and side walls (3) having stepped ends (4) which define a mouth (2) spanning less than the grooved bottom formed by the floor (5). Impact pad for continuous casting, in accordance with claim 1, characterised in that the boxlike body (1) with its wavy or grooved floor (5) is able to have an outline which can be rectangular, trapezoidal, triangular and even circular. Impact pad for continuous casting, in accordance with previous claims, characterised in that the length of the waves of the floor (5) is equal to or different from the ampitude of each wave. Impact pad for continuous casting, in accordance with claims 1 and 2, characterised in that the waves or undulations of the floor (5) of the boxlike body (1) are concentric with each other. Impact pad for continuous casting, in accordance with claims 1 and 2, characterised in that the floor (5) of the boxlike body (1) has grooves of wavy profile practiced therein.

Inventors: COTO ALVAREZ JULIO, COTO ALVAREZ, JULIO, Coto Alvarez, Julio, c/o Refractaria, S.A.
Applicants: REFRACTARIA S A, REFRACTARIA, S.A.
Application year: 2001
Main classification: B22D41
IPC codes: B22D11, B22D41