چكيده به لاتين
In the present study, gating systems were investigated for different pieces from
the point of view of melt flow into the mold and solidification of pieces, using
ProCAST2016. Firstly, fluid validation of melt was carried out using data gained
from radiography imaging. Then, thermal validation and investigation of boundry
conditions accuracy considered in simulations were examined. Studying of the
effective factors in designing (pouring time, gating system ratio and gating
system location) on pieces with different modulus were performed. Various
gating systems designed were compared with each other from the point of view
of the way of melt entrance into the mold, internal movement of the melt,
temperature distribution of the piece and location of shrinkage porosities.
Consecutive, smooth and uniform pouring can be achieved only in proper
conditions of gating system. Number, location, size, and shape of gating system
determine the rate of melt pouring into the mold. The results indicated a great
melt turbulence of melt in overflow gating systems, which is not suitable for
alloys sensitive to oxidation. Using a bottom pour gating system at which the melt
entrance velocity into the mold is less than the critical velocity could be proper.
To reduce melt velocity, increasing the width of square runner, the melt friction
in gate, and the gate cross section, while uphill movement of the melt, can be
effective. Also, the gating system should have an appropriate temperature
distribution throughout the piece. Ignoring the high velocity of melt in sprue and
runner, entrance velocity of melt into the mold gained less than 0.5 m/s, with
increasing the cross section and numbers of gates and uphill movement of the
melt. Meantime, increasing the gate numbers caused a suitable thermal
distribution in designing. Using insulation in feeder can be impressive to control
solidification of pieces with bottom pour gating systems.