The Effect of Silicon on the Formation of CO Blowholes during Solidification of Iron
Hiroyuki NOMURA, Kazumi MORI, Toshihiro NAKASHIMA
pp. 583-590
Abstract
In order to clarify the effect of silicon addition on the formation of CO blowholes, an experimental study has been made of uni-directional solidification of iron at a solidification rate of about 5mm/min. The composition range explored was: C 0.1%, O 0.006-0.011% and Si 0.01-0.04%. The critical concentration of silicon for the formation of macroblowholes has been determined to be 0.022 to 0.025%. The influence of oxygen on the critical concentration of silicon was small. The effect of silicon on the formation of macroblowholes could be explained by postulating chemical equilibrium in Fe-C-Si-O melt in the interdendritic region. It is presumed that macroblowholes are formed with the similar mechanism as that in the case of no addition of silicon.