Deffects caused by warpage or moisture in sand mold were investigated especially in castings for loom and spinning machine parts. These investigation led us to find some suitable remedies as follows for prevention of deffects.
  a) So many conditions affect on the warpage in castings, it is too difficult removing the warpage perfectly. From the results obtained, it was clarified that using pattern design considering this kind of warpage or taking a foundry method in this paper are considerably useful to remove the warpage in casting.
  b) A bad condition of surface and growth of gas holes in casting will depend a great deal upon the moisture in sand mold. It has been shown that the less the moisture content, the more easily the sound casting is gotten. To the castings in our case, however, the moisture content 11 percent is seems to be the best one. (N. T.)

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  With a review preventing the deffects caused by gas holes in iron castings cast in green sand mold, experiments as follows have been carried out in our foundry. As the causes producing these gas holes at all events are too complex and not clarified, it is difficult to remove the deffects perfectly and make sound castings satisfactorily. Investigating some causes effect on production of gas holes in castings, pouring temperature, moisture in the sand, containning clay and permeability of the sand, gives us the results as following :
  It is rather difficult to produce gas holes in cast iron castings in the case of next conditions were satisfied, a) moisture in the sand is under 9 percent, b) permeability of the sand shows its value 100 (A. F. A. unit) and c) pouring temperature is more than 1300°C. The better results of our trial operations concerning above mentioned conditions are reported in this paper. (N. T.)

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