Method to shear a strip during the casting step
AssigneeDanieli & C. Officine Meccaniche SpA
InventorsAlfredo Poloni, Nuredin Kapaj
Life of this patent
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Abstract
Method to shear a strip (15) during the casting step, wherein the casting speed is increased, with respect to a speed of a stationary regime, maintaining the thickness of said cast strip (15) constant to the value corresponding to the speed of a stationary regime, in order to determine the formation of a liquid core (16) which determines the re-melting of the adjacent skin and the breakage of the strip (15) due to the weight of the part of the strip (15a) located under the liquid core (16).
Claims11
Method to shear a strip (15) during the casting step as it emerges from a machine (10) for the continuous casting of liquid metal comprising at least a pair of casting rollers (11), said machine (10) comprising at least cooling means able to achieve the solidification of said strip (15), characterized in that it provides to increase the casting speed with respect to a speed of a substantially stationary regime, maintaining the value of speed increased for an interval (t2−t1), said increase in speed being performed keeping the thickness of said cast strip (15) substantially constant to the value corresponding to the speed of a stationary regime, in order to determine a consequent formation of a liquid core (16) inside said strip (15) at least in its segment passing at increased speed through said cooling means, said liquid core (16) causing the at least partial re-melting of the skin adjacent thereto and the breakage of the strip (15) due to the weight of the part of the strip (15a) located under said liquid core (16).
Method as in any claim hereinbefore, characterized in that, before said increase in speed, the casting speed is temporarily reduced and that, in correlation with said reduction in speed, the thickness of said strip (15) is increased in order to obtain conditions of heat exchange and solidification of the strip (15) substantially corresponding to those of a stationary regime, the function of said reduction in speed being to limit the power required from the motors associated with said casting rollers (11).
Method as in any claim hereinbefore, characterized in that the duration of said interval (t2−t1) is at least a function of the thickness of the strip (15) and of the type of metal cast.
Method as in any claim hereinbefore, characterized in that the duration of said interval (t2−t1), in the case of steel, is comprised between about 0 and 200 milliseconds.
Method as in any claim hereinbefore, characterized in that the time required to take the casting speed to an increased value, in the case of steel, is comprised between about 50 and about 600 milliseconds.
Method as in any claim hereinbefore, characterized in that it is used to remove a leading end segment (15a) of a strip (15) during the casting step.
Method as in any claim from 1 to 8 inclusive, characterized in that it is used to remove a trailing end segment of the strip (15).
Method as in any claim from 1 to 8 inclusive, characterized in that it is used to crop the strip (15) at an intermediate section thereof, in emergency situations or to separate two strips (15) of different thickness or to divide two segments of strip (15) for production reasons.
Dependencies are inferred from the claim text.