De-agglomeration rate of silicate bonded sand cores during core removal

The here presented criterion describes the disintegration kinetics of cast in sand cores, which is influenced by transient thermal and mechanical casting process loads. A semi-permanent mould setup allowing for various thermal exposure intensities was developed and used with wedge shaped, hot hardened silicate bonded sand cores. During defined mechanical agitation of such produced castings the minimum core removal mass rate was identified and combined with the de-agglomeration degree of the collected core sand. The de-agglomeration degree was evaluated from particle size analysis with specifically adapted sieving parameters and a modelling approach for the size distribution. The retained mass on the top mesh constituted the lump mass. Cast-in cores generally exhibited higher de-agglomeration rates compared to non-cast-in reference cores, which confirmed a deteriorating influence of a casting process on the sand core. Increased de-agglomeration rates and more disintegrated core lumps were observed for the samples with longer thermal exposure. Avoiding ambient humidity resulted in a significantly increased de-agglomeration rate compared to openly stored samples.