Abstract
The semi-permanent mold that far used in our country is a loam sand type, but the molding practice is quite complicated and much experience is needed to make sound mold. Addition to this the heat conductivity, resistance at high temperature is very poor.
To improve the properties of semi-permanent mold, the molding materials must be studied which have not only better beat conductivity, resistance at high temperature but also longer durability and easer to mold.
Graphite powder is one of the molding materials which satisfy above properties. And so in this first report we studied the nature of graphite base mold, using sodium silicate and bentonite as the binder.
From the standpoint of the green and dried strength, dried shrinkage, heat conductivity and durability of the mold, the best result is obtained with the following composition :
Bentonite・・・・・・・・・10%
Na2SiO3・・・・・・・・・18% (30 Báume aq. soln.)
Graphite Powder・・・・・Rem.
