LU84279A1 - IMPROVEMENTS IN CONTINUOUS CASTING PROCESSES FOR METALS - Google Patents

Description

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> C.2201 / 8207 i "

1 METALLURGICAL RESEARCH CENTER

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I CENTRUM VOOR RESEARCH IN DE METALLURGIE

Non-profit association - Vereniging zonder winstoogmerk in Brussels (Belgium)

Improvements in continuous metal casting processes

The present invention relates to improvements to the continuous casting methods for metals. They are especially applicable in the case where it is steel.

The correct development of the continuous casting process for r metals depends, as is known, on a large number of factors or parameters, among which we can cite the speed of extraction of the ingot from the ingot mold, the temperature of metal casting, thermal profile, linked to the mode and intensity of the secondary cooling of the ingot mold and ingot, the synchronization of the driving movement of the extractor rollers, etc.

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It is particularly important that all these factors are properly adjusted and adjusted, this in order to avoid accidents which could be serious, such as for example the ingot of the ingot, i especially in regions where the thickness of its skin and by; both its resistance are very low.

All other things being equal, it is important for the steelmaker to find the best combination of values to assign to these different parameters to obtain the greatest possible productivity from the casting machine, without affecting the quality of the cast metal or entering a risk zone incompatible with imperative safety rules.

Among the phenomena which one can observe during a continuous casting operation, one can notably cite! the swelling of the ingot between consecutive rolls, which, due to the ferrostatic pressure existing inside the ingot, leads to the appearance of various kinds of other defects such as »cracks, cracks, segregations, etc.

To the knowledge of the applicant, to date there is no process which makes it possible to genuinely realize, objectively, the value of this swelling and to remedy it.

1 The solution commonly adopted to limit the swelling of the ingot consists of having numerous rollers, leaving as little space as possible between two successive rollers; this arrangement has, among other disadvantages, that of provoking. faults in the event of the rollers being adjusted. In addition, it is obvious that this way of combating swelling leaves little space between the rollers for installing the ingot cooling devices, which almost inevitably leads to the use of sprinklers; Now we know that the nozzles have a localized cooling effect i on a restricted surface of the product l · 1 3 and it is therefore necessary to limit the intensity of the cooling applied by these devices, if we want to avoid thermal shock detrimental to the quality of the cast product; the direct consequence of this limitation of the local cooling intensity is the lengthening of the casting machine.

The present invention relates to a method for providing an effective and thermally interesting solution to the problem of swelling of the ingot between rollers; this process is based on the principle of balancing to be carried out between the ferrostatic pressure existing at one place of the ingot, and the external pressure at this place.

The continuous metal casting process, object of the present invention, is characterized in that an enclosure is formed around at least two consecutive rollers, in that a fluid such as p. eg water and in that the pressure of the fluid in the enclosure is adjusted to a value equal to or slightly higher than the so-called ferrostatic pressure existing in the ingot at the place where said enclosure is located.

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According to a particular embodiment of the invention, the enclosure is formed around two groups of rollers located opposite one another, on either side of the ingot; the enclosure is thus presented in the form of an envelope surrounding, in one place of the casting machine, a section of ingot and its support rollers. "

In one embodiment of the invention, the walls of the enclosure covering the rollers follow the geometric profile of these rollers, leaving a passage for the fluid / I 4 · ”

According to yet another embodiment of the invention, permanent circulation of the pressurized fluid is ensured in the enclosure; in this interesting modality, the pressurized fluid achieves both balancing the ferrostatic pressure and cooling both the rolls along which it circulates and the ingot at this location.

The method of the invention thus combines the advantages of eliminating the swelling of the ingot between rolls, of intense cooling applied to a large surface of the ingot and applied at will in the necessary places; in addition ! it makes it possible to lighten the rollers which no longer serve as a pressure device, and finally it eliminates the drawbacks due to the use of sprinklers.

Claims (4)

1. Process for the continuous casting of metals, characterized in that an enclosure is formed around at least two consecutive rollers, in that a fluid such as water is introduced into this enclosure , and in that the fluid pressure in the enclosure is adjusted to a value equal to or slightly higher than the so-called ferros-tatic pressure existing in the ingot at the location where said enclosure is located. 2. Method according to claim 1, characterized in that the enclosure is formed around two groups of rollers located opposite one another, on either side of the ingot. 3. Method according to either of claims 1 and 2 characterized in that the walls of the enclosure covering the rollers follow the geometric profile of these rollers, leaving a passage for the pressurized fluid. 4. Method according to either of claims 1 to 3 characterized in that one ensures a permanent circulation of the pressurized fluid in the enclosure.