Abstract
The author has studied the impulsive heating of molding sand, the temperature in the molding sand, and has found out the following matters to dicrease the molding sand defects at elevated temperatures.
1. Molding sand defect at the elevated temperature is caused originates by the partial heating of the molding sand and the steam pressure originated in the molding sand.
2. By mixing silica flour over 20 persents into 40 mesh molding sand, heat conductivity decreases, and partial heating increases.
3. Graphite, oil or wood flour additions decrease the defect of sand at the elevated temperatures.
4. The more the moist percent, the more the heating rate of molding sand, and the more the permeability at the dried molding sand, the more heating rate of molding sand. The rate of heating of the graphite mix melding sand is fast.
