Abstract
In order to elucidate how the molten metal flow behaves in a runner to affect sand and slag mark defects in castings, the metal flow pressure against the runner wall and its velocity were measured by using an open channel runner. Remarkable pressure variation of molten metal flow causes in the neighborhood of the sprue bottom, but this is considerably reduced as the distance from the sprue bottom increases. In the agitation flow region which involves sand and slag, a violent pressure variation is exerted on the mold wall, and the flow velocity is very fast and varies greatly. In contrast, in the stationary flow region which does not include sand and slag, the flow velocity is constant and is proportional to the cubic root of the pouring rate.
