  We present a study on the origin of the metallicity evolution of the
intra-cluster medium (ICM) by applying a semi-analytic model of galaxy
formation to N-body/SPH (smoothed particle hydrodynamic) non-radiative
numerical simulations of clusters of galaxies. The semi-analytic model includes
gas cooling, star formation, supernovae feedback and metal enrichment, and is
linked to the diffuse gas of the underlying simulations so that the chemical
properties of gas particles are dynamically and consistently generated from
stars in the galaxies. This hybrid model let us have information on the spatial
distribution of metals in the ICM. The results obtained for a set of clusters
with virial masses of ~1.5*10^15 h^{-1} M_sun contribute to the theoretical
interpretation of recent observational X-ray data, which indicate a decrease of
the average iron content of the intra-cluster gas with increasing redshift. We
find that this evolution arises mainly as a result of a progressive increase of
the iron abundance within ~0.15 R_vir. The clusters have been considerably
enriched by z~1 with very low contribution from recent star formation. Low
entropy gas that has been enriched at high redshift sinks to the cluster centre
contributing to the evolution of the metallicity profiles.
