METHOD OF MOLTEN METAL CASTING UTILIZING AN IMPACT PAD IN THE TUNDISH

Abstract

A method of molten metal continuous casting utilizing an impact pad having a non-wavy spherical top in the tundish that is impacted by the stream of molten metal entering into the tundish wherein the flow of molten metal within the tundish is optimized to improve flow patterns, reduce dead zone areas, prevent splashing while filling the empty tundish, and eliminating the open “red” eye forming in the molten metal surface layer.

Claims

1. A method of molten metal continuous casting of metals utilizing in a tundish an impact pad having a non-wavy spherical top, comprising the steps of: pouring a stream of molten metal downwardly into the tundish, at the bottom of which is located the impact pad with the non-wavy spherical top, and onto which initial impact of the stream is outwardly deflected; accelerating and optimizing in terms of total volume the stream of molten metal; and opening tundish nozzles after reaching the desired height of molten metal in the tundish, wherein thereafter the molten metal level is maintained constant and the amount of molten metal inflow into the tundish is equal to amount of molten metal that leaves the tundish through the tundish nozzles to the next continuous casting equipment.

2. A method of molten metal continuous casting of metals having different metallurgical properties utilizing an impact pad having a non-wavy spherical top in a tundish, comprising the steps of: providing a tundish at the bottom of which is located an impact pad having a non-wavy spherical top; emptying the tundish of molten metal having a first metal property; pouring a stream of molten metal having a second and different metal property downwardly into the tundish such that the stream impacts the non-wavy spherical top of the impact pad; upon impacting the spherical top the flow of molten metal is accelerated and optimized in terms of total volume; opening one or more tundish nozzles after the desired height of molten metal in the tundish is reached; and thereafter maintaining the molten metal level in the tundish constant wherein the amount of molten metal inflow is equal to the amount of metal leaving from the tundish through the tundish nozzles to the next continuous casting equipment.

3. The method of claim 2 wherein the method is performed in casting steel metal alloys.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a schematic diagram depiction of the tundish and impact pad with spherical top of the present invention.

DESCRIPTION OF THE SELECTED EMBODIMENTS

[0015] For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates. One embodiment of the invention is shown in great detail, although it will be apparent to those skilled in the relevant art that some features that are not relevant to the present invention may not be shown for the sake of clarity.

[0016] Referring now to drawing FIG. 1, a method of continuous molten metal casting utilizing an impact pad 11 with an upper surface having a non-wavy spherical top 12 in the tundish 10 is diagrammatically depicted which eliminates or significantly limits the disadvantages noted above. The casting method is characterized in that a stream 13 of molten metal flows downwardly from a ladle into the tundish 10. At the bottom 15 of tundish 10, located directly below the stream 13 is the impact pad 11 with the spherically shaped top surface 12. It is this surface which receives and outwardly deflects the initial impact flow of molten metal stream 13, and therefore the surface area of the spherical shape needs to be sufficiently large to encompass the entire flow diameter of the stream 13. Thereafter, the flow of molten metal from the stream 13 is accelerated and optimized in terms of total volume. One or more tundish nozzles 16 are opened after reaching the desired height of molten metal in the tundish, after which the molten metal level is maintained constant and the amount of inflow in molten metal into the tundish 10 is equal to amount of molten metal which leaves from the tundish 10 through tundish nozzles 16 to the next continuous casting equipment.

[0017] A further method of molten metal casting utilizing impact pad 11 is particularly suitable for the situation of molten metal casting with changed characteristics, in other words when there is molten metal with another quality in next ladle from what was in the previous ladle. In such situations, the tundish 10 must be emptied as much as possible, because the casting created by the mixture of the first and next ladle is unsaleable. The casting speed varies when the ladle is changing etc. and therefore the subject casting method extends the average retention time at lower and higher casting speeds. In this method, tundish 10 at the bottom 15 of which is located an impact pad 11 having a non-wavy spherical top 12 is emptied of molten metal having a first metal property before molten metal having a second and different metal property is poured into the tundish 10 from the ladle. After the tundish 10 has been emptied, a stream of molten metal having a second and different metal property is poured downwardly into the tundish 10 and impacts the non-wavy spherical top 12 which, due to its convex curvature, outwardly deflects the initial impact of the stream 13 of molten metal discharged from the ladle, and upon impacting the spherical top 12 the flow of molten metal is accelerated and optimized in terms of total volume. One or more tundish nozzles 16 are opened after the desired height of molten metal in the tundish 10 is reached, thereafter the molten metal level in the tundish 10 is maintained constant and the amount of molten metal inflow is equal to the amount of metal leaving from the tundish 10 through the tundish nozzles 16 to the next continuous casting equipment.

[0018] An advantage of this method of molten metal casting utilizing impact pad 11 with spherical top 12 is that there is eliminated the short circuit flow also at low casting speed, in the tundish 10 there is avoided the formation of dead zones, red eye effect on the surface of molten metal, and the entrainment of tundish slag into the molten metal volume is minimized. The result is signified by a positive impact on the metal purity from the point of view of a lack of inclusions. An economic loss arising out of failure to sell steel of undetermined quality arising from a not emptied tundish is eliminated by this method of casting.

[0019] The subject invention is industrially applicable in the field of metallurgy, particularly for the production of steel alloys, allowing big steel mills to meet the requirements of small amounts of alloy steel and economically efficient use of existing facilities.

[0020] While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes, equivalents, and modifications that come within the spirit of the inventions defined by following claims are desired to be protected. All publications, patents, and patent applications cited in this specification are herein incorporated by reference as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated by reference and set forth in its entirety herein.