The validation of each simulation code used in foundry domain requires individual approach due to its specificity. This validation can by

elaborated on the basis of experimental results or in particular cases by comparison the simulation results from different codes. The article

concerns the influence of grey cast iron density curve and different forms of solid fraction curve Fs=f(T) on the formation of shrinkage

discontinuities. Solid fraction curves applying Newtonian Thermal Analysis (NTA) were estimated. The experimental and numerical

simulation tests were performed on the castings, which were made with Derivative Thermal Analysis (DerTA) standard cups. The

numerical tests were realized using NovaFlow&Solid (NF&S), ProCast and Vulcan codes. In this work, the coupled influence of both

curves on the dynamics of the shrinkage-expansion phenomena and on shrinkage defects prognosis in grey cast iron castings has been

revealed. The final evaluation of the simulation systems usefulness should be based on validation experiment, preceded by comparing the

simulation results of available systems which are proposed in given technology.