Computational Analysis of Precipitation during Continuous Casting of Microalloyed Steel

In this paper, the kinetics of TiN, V(C,N)) and AlN precipitation in microalloyed steel during continuous casting is investigated experimentally and theoretically. The precipitate phase fraction, mean radius, number density and composition are simulated with the thermo-kinetic software MatCalc and compared with experimental results obtained from transmission electron microscopy analysis. A new methodology for modelling precipitation in cast steel is proposed, which consists of two parts: First, a Scheil - Gulliver simulation, which is carried out to obtain information on the amount of microsegregation during solidification. Then, based on this information, two precipitation kinetics simulations are performed: One with the chemical composition representative for the solute-poor core of the secondary dendrite arms, the other with the composition of the residual liquid at a fraction of 5%, corresponding to the segregated solute-rich interdendritic regions. The results of the computer simulations using the new methodology are in good agreement with experimental observation.