| It is proposed in the present paper to develop a domestic resin coated sand, and to study the effects of curing temperature and time on mechanical properties of shell molds such as tensile strength, scratch hardness and permeability. The important results obtained are as follows 1. Tensile strength of resin coated sand which have been cured on 90 sec. at 225℃ was maximum, and as curing temperature and time increased above it, the tensile strength decreased. 2. Scratch hardness of resin coated sand which have been cured on 30 sec. at 200℃ was maximum 92S. With increase of curing temperature and time, scratch hardness decreased. 3. With increase of curing temperature and time permeability of resin coated sand increased, and maximum was 220㏄/min. which have been cured on 180 sec. at 300℃. |
|
