Metallurgical apparatus – Linings
Patent
1988-02-10
1990-02-20
Bell, Janyce
Metallurgical apparatus
Linings
427226, 427228, 427236, 427133, 427135, 427239, 4274191, 4274192, 4274197, 427427, G21B 706, B05D 722
Patent
active
049019848
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method for coating a vessel which is intended to contain liquid metal and the walls of which are free of hydrogen. The invention is also concerned with the coating thus obtained.
It is known to prepare vessels for containing liquid metal by depositing on a permanent refractory lining a wearing coating which is applied in the form of an aqueous slurry containing inorganic particles and a binder. In this case, the mixture which constitutes the wearing coating contains a certain quantity of water which usually varies from 5 to 30%. This water may be necessary in order to permit setting of the binder and/or in order to facilitate the projection proper. Hardening of the wearing coating can take place in free air and at ambient temperature or by drying. Whatever solution may be adopted, this practice has the disadvantage of being conducive to introduction of water into the permanent lining by capillarity. The unfavorable consequences of this wetting of the permanent lining are as follows:
either the water thus absorbed does not succeed in escaping from the permanent lining and consequently has a potentially harmful effect on the steel which is contained within the vessel,
or the water thus absorbed can be eliminated at the time of drying of the wearing coating, thus resulting in excessive and unnecessary energy consumption in order to permit extraction of the water thus accumulated in the permanent lining.
A vessel of this type such as, for example, a continuous-casting tundish which has the intended function of regularizing the ferrostatic pressure between a casting ladle and a continuous-casting ingot-mold is usually constituted by a metallic casing within which is applied a so-called permanent refractory lining on which is deposited by spraying, for example, a refractory coating known as a wearing coating. It is this wearing coating which comes into contact with the liquid metal. Permanent linings all have a certain porosity which facilitates absorption of water as soon as the moist wearing coating is applied on these latter. The quantity of water absorbed is greater as the permanent lining is more porous or cracked and the wearing coating has a higher moisture content at the time of deposition. Thus the time spent in drying all the layers is longer as the water content of the wearing coating is higher.
When the vessel is filled with liquid steel, for example over a fairly long period of time, the temperature of the entire assembly rises to a higher value than during the drying step. In consequence, the moisture trapped within the permanent lining in the vicinity of the metallic casing vaporizes, is put under pressure and diffuses into the liquid steel after having passed back through the different layers of refractory material, thus giving rise to explosions and to pollution of the liquid metal.
The vessel which is intended to contain liquid steel in accordance with the invention makes it possible to overcome these disadvantages.
In accordance with the invention, the method for coating the interior of a metallurgical vessel provided with a permanent refractory lining, in which there is deposited on said permanent lining a refractory wearing layer which is constituted by an aqueous slurry containing inorganic particles and a binder, is characterized in that a layer impenetrable to water is applied on the permanent lining prior to deposition of said wearing layer and that, after application of the wearing layer, all the layers are subjected to sufficient drying to remove the water and the compounds containing hydrogen.
By virtue of said layer impenetrable to water, the water of the wearing layer cannot penetrate into the permanent lining and the drying time is thus considerably reduced. Moreover, at the end of the casting operation, cleaning of the metallurgical vessel is facilitated by said layer impenetrable to water since this layer prevents any adhesion between the wearing layer and the permanent lining.
Those versed in the art were dissuaded from applying a layer impenet
REFERENCES:
patent: 4339115 (1982-07-01), Daussan et al.
patent: 4750717 (1988-06-01), Pheasant et al.
The American Heritage Dictionary of the English Language, New College Edition, Houghton Mifflin Co., Boston, 1976. p. 1448.
Daussan Andre
Daussan Gerard
Daussan Jean C.
Bell Janyce
Daussan et Compagnie
LandOfFree
Method for coating a metallurgical vessel and a coating obtained does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for coating a metallurgical vessel and a coating obtained, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for coating a metallurgical vessel and a coating obtained will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1610928