フルモールド鋳造における鋳鉄溶湯の湯面の変動と上昇速度の関係

抄録

  X-ray observations of the flow of molten metal in full mold castings have indicated that gas explosions may occur continuously in the area near the gate immediately after pouring and in the foam pattern area, causing the surface of the molten metal to be blown away and the flow of molten metal to stop temporarily.

  Given that gas explosions can potentially affect the flow rate of molten metal, in this study X-ray observations were conducted to investigate the behavior of molten metal filling into the runner, near the gate, and the foam pattern area when molten cast iron was cast into the PMMA foam model using the side-bottom gating method. Moreover, the height of the surface of the molten metal (flowing into the model) was measured to determine the effect of gas explosions on the rising rate of the molten metal surface.

  Right after pouring, the molten metal was seen to flow and stop flowing repeatedly. Then when it started to flow continuously, continuous spouting of the molten metal (10Hz cycle) occurred. Despite the occurrence of dynamic phenomenon that is thought to have been caused by the gas explosion, the surface of the molten metal continued to rise at a constant speed of 8mm/s until the end of pouring.

  The duration for which the molten metal flow stopped during the initial filling process differed for each experiment. This was because the scale of the gas explosion varied depending on the behavior of the molten metal that first came into contact with the foam pattern. In other words, when the molten metal came into contact with the foam pattern in a continuous flow, the gas explosion was small-scale and the filling of the foam pattern was gradual. Discontinuous molten metal flow resulted in a large-scale explosion, causing turbulent mold filling and a longer duration in which the molten metal flow stopped.