Patent ID: 6490903
Filing Date: 2002-12-10
Classification: B21B

Abstract:
A method for thermal control of the profile of a roll in a mill comprising running control means, between at least two rolls with parallel axes, of a product to be rolled consisting of a band with two edges spaced apart by a certain width and in which at least one roll is associated with at least one ramp for spraying a heat exchanging fluid comprising a plurality of spraying members spaced apart from one another along a direction parallel to the axis of the roll and each provided with a nozzle for spraying a jet of fluid centred on an injection axis passing substantially through the axis of the roll and each jet of fluid forming, on the roll an oblong impact surface with a greater, middle axis placed on a middle plane transversally cutting the axis of the roll, each spraying member being provided with a valve operated by a flow rate adjustment system for the spraying of the roll, said flow rate adjustment system opening the valves over a portion of the ramp thereby determining the spraying of the fluid over a cooled zone of the roll and closing of the valves over the remaining portions of the ramp, the cooled zone being defined by a series of said impact surfaces having said middle axes spaced apart by a distance, the adjustment system governing the average flow rate individually, by time unit, of each of the spraying units thereby adjusting the fluid jet sprayed onto each impact surface,the method comprising: varying the distance between the middle axes of the impact surfaces in relation to the position of the impact surfaces over the length of the cooled zone so that the cooled zone comprises a central zone in which the impact surfaces are spaced by a substantially constant pitch and two transition zones extending on either side of the central zone at least up to the two edges of the band, wherein the spacing between the middle axes of the impact surfaces in each of the transition zones is reduced with respect to the constant pitch of the central zone.