Special considerations for the specific casting processes can be summarized as follows:

 

Sand Casting

 

  • Turn off Internal Heat Transfer Coefficients
  • Use a low External Heat Transfer Coefficient: Around 1.5 BTU/Hr-sqft-F
  • Only use as much sand as is necessary to absorb the heat (1” for small castings, 4-5” for large castings)
  • Generally make a rectangular mold when meshing

Investment Casting

 

  • Turn off Internal Heat Transfer Coefficients
  • Use an External Heat Transfer Coefficient: Around 10-20 BTU/Hr-sqft-F
  • Use “Shell” option when creating the mold
  • Use Void Material is necessary to remove material from shapes
  • Use View Factor Calculations to take radiation into account

Permanent Mold Casting

 

  • Turn on Internal Heat Transfer Coefficients
  • Use an External Heat Transfer Coefficient: Around 5-7 BTU/Hr-sqft-F
  • Use Internal Heat Transfer Coefficient recommendations as given in Unit 8
  • Use “None” option when meshing if the mold is part of the model
  • Use View Factor Calculations to take radiation into account
  • Use Permanent Mold Cycling when running simulations
  • Use the “Coarse”/”Fine” mesh option for warm-up cycles.