EP0499563B1 - Ingot mould for continuous casting of metallic products - Google Patents

Abstract

The invention relates to an ingot mould (10) for continuous casting of metallic products, for example billets, blooms or slabs, comprising lubricant flow orifices (22) made in its inner face (14) forming a mould. These orifices (22) are uniformly spaced with respect to each other, along the perimeter of this inner face, and open out in concave recesses (24) made in this inner face and whose surface area is substantially greater than the cross-section of the said orifices. Preferably, vertical grooves (26) extend between each concave recess (24) and the lower end (20) of the ingot mould (10) in order to ensure the discharge of the excess lubricant and of the gases caused by the cracking of the lubricant. <IMAGE>

Description

The present invention relates to an ingot mold for continuous casting of metallic products according to the preamble of claim 1.

Document JP-A-60-221 156 shows an ingot mold for continuous casting comprising lubricant flow orifices, for example of mineral oil, opening on its internal face forming a mold.

These orifices are distributed around the periphery and at different heights of the internal face of the mold.

A first series of orifices is arranged above the meniscus formed by the liquid metal which flows in the mold. A second series of orifices is placed under this meniscus.

In this case, the lubrication of the surface of the metal products which are molded in the ingot mold, for example billets or blooms, takes place substantially in the upper part thereof.

The internal face of the lower part of the mold is subjected to friction on the part of the metal product which leaves by the lower end of the mold, this friction being all the more intense as the mold has, in general, a section lower transverse in the lower part than in the upper part.

Furthermore, the edges delimiting the edges of the lubrication orifices on the internal face of the ingot mold risk catching the surface of the metal which solidifies along this internal face and of affecting the quality thereof.

Known lubrication devices generally do not ensure sufficient diffusion of the lubricant to allow the metal to slide in the mold at the speed usually required in a continuous casting process.

This is why it is known to improve the sliding of the metal in the ingot mold by subjecting it to oscillations directed along its height.

In addition to its complexity and cost, this process has the drawback of causing wrinkles to appear on the surface of the metal products shaped by the ingot mold.

The object of the invention is in particular to remedy these various drawbacks and to improve the efficiency of lubrication in an ingot mold.

It relates to a mold for continuous casting comprising lubrication means comprising lubricant flow holes, in particular of mineral oil, opening into its internal face forming a mold and regularly spaced apart between them around the periphery of this internal face, characterized in that the lubricant flow orifices open into concave recesses formed in this internal face and whose surface is substantially greater than the section of said orifices.

• la lingotière comporte dans sa face interne des rainures dont chacune s'étend sensiblement verticalement entre un évidement concave et l'extrémité inférieure de la lingotière ;
• les orifices sont situés à une hauteur comprise entre un tiers et deux tiers de la hauteur de la lingotière ;
• les évidements concaves ont une forme tronconique;
• le lubrifiant est alimenté, à partir de l'extrémité inférieure de la lingotière, par au moins un conduit principal reliant cette extrémité inférieure à une chambre annulaire de répartition du lubrifiant, ménagée dans l'épaisseur de la paroi de la lingotière, sensiblement à la hauteur des orifices, et reliée par des conduits secondaires à chacun des orifices d'écoulement;
• Les conduits secondaires sont orientés sensiblement perpendiculairement à la face interne de la lingotière.

According to other characteristics of the invention:

• the ingot mold has in its internal face grooves, each of which extends substantially vertically between a concave recess and the lower end of the ingot mold;
• the orifices are located at a height between one third and two thirds of the height of the mold;
• the concave recesses have a frustoconical shape;
• the lubricant is supplied, from the lower end of the mold, by at least one main duct connecting this lower end to an annular distribution chamber of the lubricant, formed in the thickness of the wall of the mold, substantially at the height of the orifices, and connected by secondary conduits to each of the flow orifices;
• The secondary conduits are oriented substantially perpendicular to the internal face of the mold.

• la figure 1 est une vue partielle en coupe d'une lingotière selon l'invention ;
• la figure 2 est une vue suivant la ligne 2-2 de la figure 1, la face interne de la lingotière étant représentée en vue développée.

The invention will be described in more detail below with reference to the accompanying drawings, in which:

• Figure 1 is a partial sectional view of an ingot mold according to the invention;
• Figure 2 is a view along line 2-2 of Figure 1, the inner face of the mold being shown in developed view.

FIG. 1 shows an ingot mold 10 for forming metal products, such as blooms, slabs or billets, of which a wall portion 12 has been shown.

The internal face 14 of the wall 12 forms a mold for liquid metal 16 which is introduced from above the ingot mold 10.

The upper surface of the liquid metal in the mold 10 forms a meniscus 18.

A skin of solidified metal 19, for example of a billet in formation, is in contact with the internal face 14 of the wall 12. This skin 19 will thicken, from the surface of the meniscus 18, adjacent to the internal face 14 towards the lower end 20 of the mold 10.

The wall 12 of the mold 10 is of greater thickness at its lower end 20 than at its upper end 21. Thus, the internal face 14 of the wall 12 delimits a volume whose section is decreasing.

As can be seen in FIGS. 1 and 2, lubrication orifices 22 regularly spaced apart along the periphery of the internal face 14, are arranged at the same height between the first third and the second third of the height of the mold. .

Each orifice opens into a concave recess 24 on the internal face 14.

Each concave recess 24 is centered on the orifice 22 which opens into it and has, for example, a frustoconical shape so that its edges form a slight angle with the internal face 14.

Grooves 26, hollowed out in the internal face 14, extend substantially vertically, from each concave recess 24 to the lower end 20 of the mold 10.

A main duct 28 for supplying lubricant, for example mineral oil, formed in the thickness of the wall 12, connects the lower end of the mold 10 to an annular distribution chamber 30, formed in the thickness of the wall 12, substantially at the height of the orifices 22.

Secondary conduits 32 connect each orifice 22 to the distribution chamber 30.

For manufacturing convenience, the chamber 30 was produced by digging a groove 34 all around the mold 10 and closing this groove at the level of the external face 36 of the wall 12, for example using elements 38 welded to the face 36 of the wall 12.

In the figures, the proportions of the lubrication members such as the orifices 22, the concave recesses 24, the grooves 26, have been exaggerated with respect to the dimension of the ingot mold, to better show their arrangement.

For an ingot mold used for the production of billets with a cross section of 170 mm on a side, the orifices 22 have, for example, a diameter of between 0.5 and 1 mm, and are spaced apart by 5 mm. The grooves are, for example, 1 mm wide.

The lubrication means described above are used to lubricate the lower part of the mold 10. This usually includes lubrication means at the level of its meniscus, which are known and which have therefore not been described, which are used in a complementary manner with the lubrication means according to the invention.

The supply of lubricant to the lubrication means according to the invention takes place through the lower end 20 of the mold, thanks to the main conduit 28. The lubricant flows at the level of the internal surface 14 through the orifices 22. The recesses concaves 24 ensure good distribution of the lubricant.

The grooves 26 make it possible to evacuate the excess of lubricant emerging from the orifices 22 as well as the gases produced by the cracking of the oil on contact with the hot metal.

The lubrication of the lower part of the mold 10 is much more effective than in known arrangements. The sliding of the cast metal is improved in such a way that it is possible to envisage eliminating the means for oscillating the ingot mold. Wrinkles on the surface of the cast metal, due to these oscillations, are therefore avoided or at least attenuated and the ingot mold has an extended service life.

It will also be appreciated that these results are obtained by simple and relatively inexpensive means, the implementation of which is particularly easy.

Claims (6)

1. Mould for continuous casting of metal products, including lubrication means comprising orifices (22) for the outflow of lubricant, especially mineral oil, which are made in its wall (12) and emerge into its mould-forming internal face (14), these orifices being uniformly spaced apart along the perimeter of this internal face, characterized in that the orifices (22) emerge into concave cavities (24) which are made in this internal face and which have a surface area substantially greater than the cross-section of the said orifices.
2. Mould according to Claim 1, characterized in that it includes grooves (26) in its internal face (14), each groove extending substantially vertically between a concave cavity (24) and the lower end (20) of the mould.
3. Mould according to Claim 2, characterized in that the orifices (22) are located at a height lying between one third and two thirds of the height of the mould.
4. Mould according to any one of the preceding claims, characterized in that the concave cavities (24) have a frustoconical shape.
5. Mould according to Claim 2, characterized in that the lubricant is fed, from its lower end (20), via at least one main conduit (28) connecting this lower end (20) to an annular chamber (30) for distributing the lubricant, this chamber being made in the thickness of the wall (12) of the mould, substantially at the height of the orifices (22) and connected via secondary conduits (32) to each of the outflow orifices (22).
6. Mould according to Claim 5, characterized in that the secondary conduits (32) are oriented so as to be substantially perpendicular to the internal face (14) of the mould.

Images