Resonance mould system in continuous casting

Mannesmann Demag has designed a new continuous casting mould, a special feature of which is the suspension of the water jackets in leaf springs. By using leaf springs, play free and wear free articulation can take place. Thus, there is a tenfold improvement in guiding accuracy, the result of which is a significant reduction in strand friction and better surface quality. At the same time, the stress on the drive is reduced as a result of 100% inertia load compensation. The dynamics are further improved by reducing the oscillating masses, with the result that the servohydraulic drive can be used to its full potential. With this option, non-sinusoidal oscillation and high frequencies with small stroke length can be reliably controlled. The new concept offers different aspects of quality improvement and, most important, creates the conditions required for increasing casting output. Besides basic system concepts, this paper presents latest developments including the integration of electromagnetic stirrers into the mould, using a stirrer which can be adjusted but which does not oscillate. Latest mould types are designed as a cassette type mould, enabling water jackets and foot rollers to be lifted out while the leaf springs and the drives fixed on an auxiliary frame stay in the plant. This design for new plants even allows the first segment to be lifted out through the frame, or the cassette and first segment to be removed together in one step. A new computer aided system is also described, introducing the concept of utilising features of the servohydraulic drive to measure and calculate the friction force of the strand. The purpose of this is to optimise parameters on line while casting. (C) 1997 The Institute of Materials.