鑄鋼生型砂の硏究

— 粒形狀の影響について —

抄録

  Succeeding to the last report, the authors have studied the effect of the sand grain shape on the characteristics of moulding sands carrying experiments on its high temperature properties chiefly and have tried to derive the answer that what shape of sand grain is most suitable for moulding sands.
  The results obtained are as follows ; -
 1. The difference of sand grain shape is hardly distinguished by the test on green properties.
 2. Rounded sands have good flowability and permeability but have considerably bad porosity.
 3. Rounded sands show less high temperature expansion and less high temperature crack.
 4. The reason why rounded sands show less high temperature expansion in spite of its good flowability is that the less contact resistance of sand grains.
 5. The contact resistance of sand grains is a function of size and shape of porosity as permeability like.
 6. By measuring permeability of sands, the authors can assume the volume of expansion at high temperatures fairly well.