1. During holding at temperatures of 950–1050°C vanadium carbonitrides, which are present in steel 16GFL in the cast condition, partially or completely dissolve and their size distribution changes. 2. An analysis of thermodynamic calculations allows one to predict the changes in the sizes of the austenitic and ferritic grains after alloying with vanadium. 3. The effect of the dispersed particles on the austenitic and ferritic grain sizes can be determined by using the parameter\([\mathop \sum \limits_i (f_i /d_i )]^{ - 1}\). This parameter represents the volume fraction (fi) and the size distribution of the particles (di) at the normalization temperature. The carbonitrides will have an effect on the grain size if\([\mathop \sum \limits_i (f_i /d_i )]^{ - 1}\)< 100 μm. 4. Through the use of thermodynamic calculations, the proposed model allows one to predict the particle size distribution and the parameter\([\mathop \sum \limits_i (f_i /d_i )]^{ - 1}\) at the austenization temperature from data on the particle size distribution in the initial condition.