抄録
In casting in cement sand mold sand holes tend to increase with increasing either pouring time or pouring rate. To eliminate sand holes it needs to control the two factors in an adequate way. Sand holes are formed more often in cement sand mold than in sand molds bonded with clay, sodium silicate or oil. There is no relation between the occurence of sand holes and the strength of sand mold measured at room temperature, but a close relation between the formation of sand holes and the value of shock at high temperatures.
