Abstract: The model experiments on the accumlation of large oxide inclusion in the bottom of ingots during pouring were carried out by using NH4C1-water solution and plastic particles.The mechanism for the accumulation of inclusion were proposed. The quantity of inclusions may be indicated by the following equation:
$Q = \frac{{A{\rm{\cdot}}b}}{{1 - \alpha }}(\int_{{t_1}}^{{t_0}} {(\overline V - {U_S})} {C_0}dt + \int_{{t_0}}^{t + {t_s}} {(\overline V - {U_S})} k{C_0}dt)$
It was found that the result of experiments were in good agreement with plant practises.
Accumulation of the large inclusion on the bottom of ingots is effectively inhibited by the application of the heat-generating agent in the ingot cap but the adding time and method is of very important.
For reducing inclusion, it is necessary to cast steel in a suitable temperature.