CAPCAST's porosity module, PORO is the next step in the evolution of
solidification analysis software. Used in conjunction with CAP, this porosity
module takes data from solidification and makes highly accurate predictions
about the location and amount of porosity formed in your casting.

Porosity and Shrinkage Detection in Iron Casting

* Generally in aluminum castings, the solidification pattern gives a good
indication of where shrinkage porosity will be located. Directional solidification
in aluminum castings reduces (or eliminates) porosity.
* Nodular Iron is different. The carbon present in the iron tends to expand during
solidification. Even if shrinkage is predicted by looking at the solidification
pattern, it tends to be reduced in the real casting because of that expansion.
* Directional solidification in iron castings does not always mean quality castings
as shrinkage can often occur near gates and risers. This renders general
solidification analysis less useful for nodular iron castings.
* PORO goes beyond conventional solidification analysis and analyzes how gas
pressure, metal pressure, thermal expansion, and cooling rate influence the growth
of porosity. It gives a more accurate prediction of porosity in iron castings because
it does not rely exclusively on solidification patterns.

CAPCAST highlights the porosity distribution of a casting

Simulation considerations for Fe castings: inoculation effects, water content in
greeen sand mold, and mold wall movement.

Pictured is a casting with no hot spots, shrinkage occurs despite this, and is
evident with CAPCAST.

Thermophysical properties of the green sand
mold vary according to water content

Casting volume change is dependent on
position, time, temperature, allow composition,
and mold wall movement.

On the top is the casting
solidification pattern. Most
analysis codes would be
incapable of detecting porosity
in this casting because of good
"Directional" solidification. There
are no isolated regions for
shrinkage to occur. The
image to the left of an
aluminum control arm prove
this point:

However, PORO tells a different
story. The image to the left is a
representation of where porosity
was likely to occur.

PORO's predictions were backed
up by a physical investigation of
the actual casting.