| Through reviewing the development of the full mold process with unbonded sand molds, it is emphasized that this process has great advantages in comparision with the conventional cavity mold process. To find the optimum pouring rate range for gray iron castings in full molds with foamed polystyrene patterns, the relations of sprue area vs. pouring rate and of pouring temperature vs. pouring rate were investigated through foundry experiment. The patterns used in this experiment were designed according to Wallace`s report for bar, cylinder and plate castings which was authorized by AFS in order to compare quantitatively the experimental results with the formula for the conventional cavity mold process. The sprue choke sections were varied in six steps, namely, from 0.75 to 2.5 times of Wallace`s formula. It was cleared by this study that sprue area, shape of casting, and pouring temperature were the dominant factors to determine the pouring rate for a sound casting. |
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