The paper presents the results of experimental-simulation tests of expansion-shrinkage phenomena occurring in cast iron castings. The

tests were based on the standard test for inspecting the tendency of steel-carbon alloys to create compacted discontinuities of the pipe

shrinkage type. The cast alloy was a high-silicone ductile iron of GJS - 600 - 10 grade. The validation regarding correctness of prognoses

of the shrinkage defects was applied mostly to the simulation code (system) NovaFlow & Solid CV (NFS CV). The obtained results were

referred to the results obtained using the Procast system (macro- and micromodel). The analysis of sensitivity of the modules responsible

for predicting the shrinkage discontinuities on selected pre-processing parameters was performed, focusing mostly on critical fractions

concerning the feeding flows (mass and capillary) and variation of initial temperature of the alloy in the mould and heat transfer

coefficient (HTC) on the casting - chill interface.