GB1562102A

GB1562102A - Anti-splash or float device for ingot moulds

Info

Publication number: GB1562102A
Application number: GB44189/76A
Authority: GB
Original assignee: Agence National de Valorisation de la Recherche ANVAR
Current assignee: Bpifrance Financement SA
Priority date: 1975-10-28
Filing date: 1976-10-25
Publication date: 1980-03-05
Also published as: FR2329382A1; ZA766334B; CA1099886A; IT1104551B; LU76082A1; JPS5260235A; SE7611918L; FR2329382B1; BE847727A; ES452815A1; SE424515B; DE2648462A1; NL7611915A

Description

(54) ANTI-SPLASH OR FLOAT DEVICE FOR INGOT MOULDS (71) We, AGENCE NATIONALE de VALORISATION de la RECHERCHE, a French Company of 13, rue Madeleine Michelis- 92200- Neuilly-sur-Seine, France, do hereby declare the invention, for which we pray that a Patent may be granted to us,.

and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an anti-splash or float device for mitigating splashing of droplets of molten steel when pouring metal into an ingot-mould.

When the steel is cast directly in a stream, a device known as a "splashguard" is usually placed at the bottom of the ingot-mould. When the steel is "bottom-cast", a "cushion" or "float" is used to support the casting material. The function of these devices is to eliminate splashing of droplets of molten steel on the cold walls of the ingot-mould, in contact with which these droplets solidify and ultimately cause the appearance of surface defects in the ingot or finished product.

At the time of direct casting in a stream, these devices also make it possible to reduce the impact of the stream of steel against the base of the ingot-mould and consequently to reduce wear of the latter.

They also contribute to reducing the sudden cooling of steel coming into contact with the mass of the ingot-mould through the intermediary of its base, thus causing "bottle bottom" shrinkage of the ingot.

Various devices of this type are already known, in particular splash-guards produced from a strip of corrugated cardboard wound in a spiral. However, these devices are not completely satisfactory since they have a relatively high cost price, are difficult to use and have a limited efficiency.

The object of the present invention is to remedy these drawbacks.

According to the present invention there is provided an anti-splash or float device for placement in an ingot-mould, comprising a unit of strips all for standing on edges thereof and defining an array of cells forming a rosette, surface portions or the strips being interconnected to provide inner and outer concentric annular areas of polygonal cells wherein each cell is defined by surfaces of the strips and each cell of the inner annular area defining a smaller surface area than all of the outer annular area whereby there are more cells per unit area of the rosette in the inner annular area than in the outer annular area so that, in use, a stream of molten metal tends initially to strike the strips of the cells of the more densely packed inner annular area and splashing of the metal is mitigated.

Preferably, a plate extends over the inner annular area of polygonal cells and has a surface thereof secured to corresponding edges of the strips.

Preferably also, the strips defining the cells are made from steel, aluminium, or asbestos, or a silica alumina complex.

The present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic vertical sectional view of an ingot-mould provided with an anti-splash or float device according to the invention, at the time of casting.

Figure 2 is a plan view of a device in the form of a rosette.

Figure 3 is a partial vertical sectional view of the lower part of an ingot-mould in which device in the form of a rosette, having an upper conical surface is placed.

Figure 4 is an elevational view of a device in the form of a rosette having an upper conical surface.

Figure 5 is a partial vertical sectional view of an ingot-mould in which device in the shape of a rosette, having an upper surface constituted by a conical cup is housed.

Figure 6 is a perspective view of a variation of a device constituted by placing several rosettes one above the other.

Figure 7 is a perspective view of a variation of a device in the form of a rosette, provided with facings.

Figure 8 is a diagrammatic vertical sectional view of an ingot-mould used for bottom-casting and in which a float device according to the invention is located.

Figure 9 is a partial sectional view of the ingot-mould of Figure 8, in which a variation of the float device is located.

Figure 1 shows diagrammatically an ingot-mould 1, above which is located a casting ladle 2 comprising a nozzle 3 having a slide valve, from which a stream of molten metal 4 flows along the axis of the mould. The ingot-mould 1 comprises two parts, namely a conical cast iron mould 5, open at the top and bottom and a base 6 constituted by a strong cast iron plate and on which the mould 1 rests. A device 7 constituting a splash-guard for the ingotmould is placed on the base 6 and the stream of molten metal 4 strikes the centre of the splash-guard. This splash-guard device 7 is mainly intended to prevent droplets of molten steel from splashing towards the cold wall of the ingot-mould constituted by the conical mould 5.

The device 7, which may be constructed in one of the shapes illustrated in Figures 2 to 8, is formed from one or several strips of a combustible or non-combustible material, such as cardboard, which are placed edgewise on the base 6 of the ingot-mould 1. The strip or strips constituting the splash-guard device 7 define a substantially polygonal array of cells 8 (Figure 2). Due to this, the stream of steel 4 which falls mainly on the central part of the splashguard device 7 is in practice not able to splash out towards the cold side wall of the ingot-mould 1, owing to the presence of the strips placed edgewise and thus forming screens.

The splash-guard device is in the form of a rosette, as illustrated in Figure 2. In this case, the density of the cells 8 decreases from the centre of the rosette towards its periphery. In other words, the walls of the various cells are very close to each other at the centre of the rosette and are less so on approaching the periphery.

In this case, the cells have a hexagonal shape but they could naturally be of any other polygonal shape.

The splash-guard device 7 may have a curved, circular or oval periphery, as will be seen hereafter, or a polygonal periphery. The upper and lower surfaces of the device 7 may both be flat or its upper surface 7a may be conical, as shown in Figures 3 and 4. This arrangement is particularly advantageous, because in practice the vertical stream of steel diverges from the centre of the base of the ingotmould by only several centimetres. Consequently, the action of the splash-guard device 7 in preventing the splashing of steel droplets mainly occurs at the centre and it is thus advantageous to increase the depth of the latter at this point.

According to one variation, illustrated in Figure 5, the splash-guard device 7 has a hollow upper surface 7b, in the shape of a conical cup. Again the splash-guard device 7 prevents splashing and fulfils the function of a "flaw-guard" preventing molten droplets from solidifying on the wall 5 of the ingot-mould 1.

In the variation illustrated in Figure 6, the splash-guard device 9 is constituted by superimposing several similar splash-guard devices 7 in the form of rosettes (three in number in the examples shown), connected by interposed sheets 10 provided with adhesive. This increases the probability of the stream of molten steel encountering vertical strips. In this embodiment, the splash-guards 7 may also be constituted by an array of cells of equal crosssection.

Ths splash-guard device may be of oval shape. By sawing or cutting the sides of the splash-guard device in the shape of a rosette or oval or of a large panel obtained as above-described, it is possible to obtain square or rectangular splash-guards having straight or truncated corners.

The centre of the splash-guard may be reinforced by inserting in the lower part, either a metal plate, particles of wood or compact cardboard, or a block of the "honeycomb" array wherein the axes of the cells are horizontal, or a block of multi-layer corrugated cardboard.

The splash-guard device may be obtained from a structure of the "honeycomb" type. This "honeycomb" structure may be collapsible and retained in a rosette form by clipping two end strip surface portions together or sticking these together by means of an appropriate adhesive. In this case, the splash-guard device, which is collapsible in the manner of a fan occupies a volume equal to approximately twenty times the non-expanded volume.

In this latter embodiment, in order to reduce transportation costs and the storage space required, the splash-guard device may be delivered in the unexpanded form but, in this case, the outer sides which have to be brought together then stuck after opening out in the fan shape, are provided with contact adhesive protected by a film which can be easily removed.

In the embodiment illustrated in Figure 7 the splash-guard device 14 comprises facings 15, 16 stuck to two sides of the splash-guard device 14, which is thus sandwiched. In practice, to provide good rigidity of the splash-guards or cushions, paper facings of approximately 10cm x 10cm are stuck on each side to the central part. When the splash-guard is conical or concave, the paper square is split from one edge to the centre in order to fit the cone or cup-shape.

When using a splash-guard in the form of a rosette 7 or having a nonhomogeneous rectangular mesh, i.e. a mesh with a varying cell area from the centre towards the periphery, the lower central part may also be reinforced, as above-mentioned for homogeneous arrays by the adhesion of a metal sheet or wood particles to form a lower facing.

In order to decrease the inflammability of the splash-guard device, or even make the latter fireproof, various materials may be used in place of cardboard, such as steel, a cardboard/steel complex, asbestos, an asbestos/steel complex, a steel/glass cloth complex. These materials are made into a splash-guard according to the same methods as for the cardboard strips of a cellular structure of the "honeycomb" type.

An effective thermal screen retarding the transmission of heat between the molten steel and the base 6 of the ingot-mould is obtained by using inserted sheets or facings, such as the sheets 10 in the embodiment of Figure 6 and the sheets 15 and 16 in the case of Figure 7. These inserted sheets or facings are made from slightly inflammable, non-combustible or refractory material, such as steel, aluminium, asbestos or a silica/alumina complex. A single sheet, such as the sheet 16 may be used as the lower facing of the splashguard device. In fact, since this sheet is in direct contact with the base of the ingot mould, it withstands the impact of the stream of molten steel better and for a longer period of time.

Figure 8 illustrates the use of the device in the case of bottom-casting. In this case, the metal enters the ingot-mould 1 from the centre of the base plate constituting the base of the ingot-mould and where a nozzle of refractory material has been located. Pouring takes place in an adjacent column 17 whose inner volume is con nected to the orifice provided in the centre of the base plate 6. In this case, a splashguard device 18 is placed on the base of the ingot-mould 1, which device is intended to fulfil the further function of a cushion or float rising on the surface of the steel, as the level of the latter rises in the ingot-mould 1, during casting. Located above this float 18 are bags of insulating powdered products. In this case, the device 18 advantageously comprises a conical or concave lower surface, i.e. of lesser depth at the centre at the point where the stream of molten steel escapes.

In the case illustrated in Figure 9, the base plate comprises a central conical recess. The splash-guard device 19 is in the shape of an inverted truncated cone in order to fit this conical recess.

The splash-guard device may be used in all ingot-moulds, for direct casting using gravity pouring of the molten steel, or bottom-casting. It is clearly more efficient than the splash-guard devices currently on the market. It may be made in various shapes to fit a variety of ingot-mould and may be assembled before use in order to reduce transportation and storage costs.

WHAT WE CLAIM IS: 1. An anti-splash or float device for placement in an ingot-mould, comprising; a unit of strips all for standing on edges thereof and defining an array of cells forming a rosette, surface portions of the strips being interconnected to provide inner and outer concentric annular areas of polygonal cells wherein each cell is defined by surfaces of the strips, and each cell of the inner area defining a smaller surface area than each cell of the outer annular area whereby there are more cells per unit area of the rosette in the inner annular area than in the outer annular area so that, in use, a stream of molten metal tends initially to strike the strips of the cells of the more densely packed inner annular area and splashing of the metal is mitigated.

2. A device as claimed in claim 1, in which a plate extends over the inner annular area of polygonal cells and has a surface thereof secured to corresponding edges of the strips.

3. A device as claimed in claim 2, in which the plate has said surface thereof secured to corresponding edges of the strip on a side intended to be the lower side, in use, of the inner area of polygonal cells.

4. A device as claimed in any one of claims 1 to 3, in which the surface portions of the strips are provided with layers of adhesive whereby said surface portions are interconnected to provide an array of the cells.

5. A device as claimed in any one of Claims 1 to 4, in which the unit is collapsible and is retained in rosette form by the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. but, in this case, the outer sides which have to be brought together then stuck after opening out in the fan shape, are provided with contact adhesive protected by a film which can be easily removed. In the embodiment illustrated in Figure 7 the splash-guard device 14 comprises facings 15, 16 stuck to two sides of the splash-guard device 14, which is thus sandwiched. In practice, to provide good rigidity of the splash-guards or cushions, paper facings of approximately 10cm x 10cm are stuck on each side to the central part. When the splash-guard is conical or concave, the paper square is split from one edge to the centre in order to fit the cone or cup-shape. When using a splash-guard in the form of a rosette 7 or having a nonhomogeneous rectangular mesh, i.e. a mesh with a varying cell area from the centre towards the periphery, the lower central part may also be reinforced, as above-mentioned for homogeneous arrays by the adhesion of a metal sheet or wood particles to form a lower facing. In order to decrease the inflammability of the splash-guard device, or even make the latter fireproof, various materials may be used in place of cardboard, such as steel, a cardboard/steel complex, asbestos, an asbestos/steel complex, a steel/glass cloth complex. These materials are made into a splash-guard according to the same methods as for the cardboard strips of a cellular structure of the "honeycomb" type. An effective thermal screen retarding the transmission of heat between the molten steel and the base 6 of the ingot-mould is obtained by using inserted sheets or facings, such as the sheets 10 in the embodiment of Figure 6 and the sheets 15 and 16 in the case of Figure 7. These inserted sheets or facings are made from slightly inflammable, non-combustible or refractory material, such as steel, aluminium, asbestos or a silica/alumina complex. A single sheet, such as the sheet 16 may be used as the lower facing of the splashguard device. In fact, since this sheet is in direct contact with the base of the ingot mould, it withstands the impact of the stream of molten steel better and for a longer period of time. Figure 8 illustrates the use of the device in the case of bottom-casting. In this case, the metal enters the ingot-mould 1 from the centre of the base plate constituting the base of the ingot-mould and where a nozzle of refractory material has been located. Pouring takes place in an adjacent column 17 whose inner volume is con nected to the orifice provided in the centre of the base plate 6. In this case, a splashguard device 18 is placed on the base of the ingot-mould 1, which device is intended to fulfil the further function of a cushion or float rising on the surface of the steel, as the level of the latter rises in the ingot-mould 1, during casting. Located above this float 18 are bags of insulating powdered products. In this case, the device 18 advantageously comprises a conical or concave lower surface, i.e. of lesser depth at the centre at the point where the stream of molten steel escapes. In the case illustrated in Figure 9, the base plate comprises a central conical recess. The splash-guard device 19 is in the shape of an inverted truncated cone in order to fit this conical recess. The splash-guard device may be used in all ingot-moulds, for direct casting using gravity pouring of the molten steel, or bottom-casting. It is clearly more efficient than the splash-guard devices currently on the market. It may be made in various shapes to fit a variety of ingot-mould and may be assembled before use in order to reduce transportation and storage costs. WHAT WE CLAIM IS:

1. An anti-splash or float device for placement in an ingot-mould, comprising; a unit of strips all for standing on edges thereof and defining an array of cells forming a rosette, surface portions of the strips being interconnected to provide inner and outer concentric annular areas of polygonal cells wherein each cell is defined by surfaces of the strips, and each cell of the inner area defining a smaller surface area than each cell of the outer annular area whereby there are more cells per unit area of the rosette in the inner annular area than in the outer annular area so that, in use, a stream of molten metal tends initially to strike the strips of the cells of the more densely packed inner annular area and splashing of the metal is mitigated.

bonding of two adjacent end strip surface portions together.

6. A device as claimed in any of Claims 1 to 5, in which the polygonal cells are all hexagonal.

7. A device as claimed in any one of Claims 1 to 6, including a further, generally similar, second unit which has a connecting plate substantially coextensive therewith and, in use, overlies the aforesaid unit, the connecting plate having one surface secured to lower edges of the strips of the second unit and having another surface secured to upper edges of the strips of the first unit.

8. A device as claimed in any of Claims 1 to 6, in which the inner annular area of the unit projects transversely of the device with respect of the outer annular area.

9. A device as claimed in any of Claims 1 to 6, in which the inner annular area of the unit is recessed with respect to the outer annular area.

10. A device as claimed in Claim 1, in which facing sheets or plates are bonded onto either the upper or the lower surface of the device, or onto both upper and lower surfaces.

11. A device as claimed in any of Claims 1 to 10, in which the strips defining the cells are made from steel, aluminium, or asbestos or a silica/alumina complex.

12. An anti-splash or float for an ingot-mould substantially as hereinbefore described with reference to any one of the Figures of the accompanying drawings.

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