Method for varying the width of a slab cast in a continuous-casting mould

摘要

A method for varying the width whereby the width of a slab which is being cast is varied by means of a movement of the narrow faces of a continuous-casting mould by activation of a horizontal actuation device and of a rotary actuation device which can be actuated independently of the horizontal actuation device. The period of the variation operation for varying the width is divided into a period for varying the forward narrowing in which each narrow face is inclined towards the centre of the mould, and a period for varying the rearward narrowing in which each wall of the mould is inclined in a direction so as to separate it from the centre of the mould. The acceleration of the horizontal movement of each narrow face is determined by means of the permitted resistance to deformation of the skin as a parameter for each period. The angular speed of the rotary device or the difference in speeds between the upper and lower ends of the narrow face are also determined. The operation for varying the width is carried out while maintaining the acceleration and the angular velocity or the difference in velocities at constant levels in the respective periods.