9th ECCC European Continuous Casting Conference – ECCC 2017

IDS is a thermodynamic-kinetic-empirical tool for solidification, microstructure and material properties of steels, which has been developed at Aalto University in Finland since 1984. IDS calculates phase fractions, phase transformations and several solidification, cooling and reheating related phenomena, including inclusions and precipitates from liquid state to room temperature and during reheating. The present solutes available in IDS are C, Si, Mn, P, S, Cr, Ni, Mo, Al, Cu, N, Nb, Ti, V, Ca, B, O, Ce, Mg, H. The heart of the model is the large thermodynamic, diffusion and microstructure data bank made through our own assessment work. Particularly, the thermodynamic database of IDS has been clearly extended during the last years. IDS also includes many special modules, such as quality prediction, scale formation, gas behavior, material properties and austenite decomposition. The material property module was recently extended by adding new sub-modules of creep rate and elastic modulus, and the austenite decomposition module was extended with the effect of boron. The quality of the calculations depends significantly on the underlying thermodynamic data. A cooperation has been carried out with the Montanuniversitaet Leoben to further development and validate the IDS databases. A special research field at the Chair of Ferrous Metallurgy in Leoben is the identification of peritectic steel grades by means of DTA/DSC-measurements in the lab. Beside the investigation of the initial transformation behaviour (pure δ or γ, hypo- or hyper-peritectic) such measurements can be used to determine full phase diagrams. A new finding was, that the quite important silicon and manganese interaction in Fe-C-Si-Mn system was insufficiently described. A full section of a Fe-C-1Si-2Mn (wt.-%) system was investigated by systematic DSC measurements and this new results were implemented into IDS. The transversal cracking during continuous casting depends strongly on the austenitic grain size. the grain growth of selected Fe-C-1%Si-2%Mn alloys was investigate in-situ by high-temperature laser-scanning-confocal-microscopy (HT-LSCM) trials. The combined use of selected alloy variations, DTA/DSC-measurements and HT-LSCM observations are very beneficial tools to further develop and validate software tools like IDS, especially for new demanding steel grads.