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Low
Expansive Olivine Sands |
SURFACE
FINISH AND DIMENSIONAL CONTROL
INCAST olivine sub-angular 50 mesh/300 µm |
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 INCAST
olivine sands deliver improved dimensional stability and superior
surface finish in both ferrous and non-ferrous applications.
With a low, uniform thermal expansion, olivine will produce
castings with close dimensional control and smooth surface
finish. Olivine’s low rate of thermal expansion greatly
reduces the incidence of grain movement to produce stable
cores and molds which virtually eliminate wall movement or
centerline shrinkage.
 Olivine’s
linear thermal expansion is lower than silica and relatively
uniform over its entire use temperature range. Low thermal
expansion greatly reduces mold wall movement for more stable
molds capable of producing castings with closer dimensional
control and consistency. This effect is most pronounced in
the casting of aluminum alloys where olivine’s greatest
differential in thermal expansion compared to silica sand
occurs in the 600 - 800°C pouring temperature range of
most aluminum alloys.
Olivine will stay in the system longer to promote higher
green strengths, and maintain those improved properties through
the repeated recycling of the sand and clay mixture. Olivine’s
low thermal expansion also eliminates the need for cushioning
additives such as cellulose or cereal for a more easily controlled
green sand system of sand, clay and water.
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