Avaliação experimental e teórica do torque no laminador de chapas grossas da Usiminas

Abstract

Controlled rolling, CR, is an effective means of producing steels with high mechanical resistance and high toughness. CR is a thermomechanical process commoly employed in plate mills throughout the world in the production of heavy plates of high resistance to shipbuilding, grade API steels destined to the welding of tubes as well as to other structural applications. The main objective of CR is to cause grain refinement in the plate resulting in a simultaneous increase in the mechanical resistance and in the toughness of the steel. Presently, the steels of grade API-X70 have been used in the majority production of tubes of large diameter since they present high tensile stress, high toughness and good weldability. The demand of high strength steels (API-X70) or higher degrees is growing in the world. The production of these steels, using the conventional process of controlled rolling, demands high torques of lamination, in function of the severe processing conditions. As a result of these high rolling loads of Plate Mill, the transmission trees (spindles) of the main motors for the work cylinders receive torques that can reach the strength limit of spindles. The present work aims measure this torque during the lamination, through instruments of experimental measurement (strain gage), comparing the results with calculations based on available equations in the literature, adjusting equation for torque calculation with benefits, defining parameters for great rolling conditions on Usiminas Plate Mill.