Simulation des Erstarrungsprozesses und des Inline-Walzens von im Strang gegossenen Stahlknüppeln mit flüssigem Kern

摘要

In order to investigate the influence of mechanical soft reduction of steel billets with liquid core on the internal quality of billets, casting and soft reduction experiments were carried out. Moreover, the temperature, stress and strain fields in billets were calculated with the finite Element Software ABAQUS to determine the shell thickness, the solid fraction, the reduction efficiency and the reasons for crack formation during the soft reduction. The Finite Element Models were verified with the measured mould and billet surface temperatures. The results show that the centre segregation and shrink holes in the core area have been improved and the core density has increased by applying the soft reduction, especially with a solid fraction of ca. 0.9. With a smaller solid fraction the internal cracks will be caused in the area near the zero ductility temperature. On the contrary, the reduction efficiency will be very small if the solid fraction is larger. In this case, the volume contraction in the core area due to the solidification will not be compensated any more.