各種粘結剤におけるCO₂法の常温並びに高温の性質について

抄録

  Various material svere added to molding sand to improve chemical properties, The Study is made on the effect of various material in sodium silicate molding sand, on the finess of molding sand, moisture in sodium silicate molding sand, on the fines of molding sand, moisture in sodium silicate, residual moisture, strength after heating at elevated temperature, and expansion at elevated temperature.
  The results obtained are as follows:
  1. Coal powder is used 1∼2%, and pitch powder is used 1∼3% to increase collapsibility of molding sand.
  2. Molasses seduces strength of molding sand on sodium silicate.
  3. Strength increases with of finess number.
  4. Residual moisture does not change with gassing time and atmospheric temperature.
  5. Strength due to preservation and drying is greater than gassing strength.
  6. Steangth of sodium silicate bending sand increases with increasing humidity and temperature.
  7. Hardening in accelerated by raising temperature and by adding water but the strength is decreased adding water in sodium silicate.
  8. Strength after heating at elevated temperature is maximum at the temperatures 100∼200 °C and at 1100 or at 900 °C also.
  9. Expansion at elevated temperature is maximum at 600∼650°C, and falls rapidly, and this temperature is not affected gassing time and volume of bording, And also this temperature rises with higher purity of molding sand and added materials.