Significantly Reducing Common Casting Issues in Permeable Molds By Casting Under Pressure

Sunday, April 17, 2016: 8:00 AM
Room: 207 AB (Minneapolis Convention Center)
Randy Oehrlein , Carley Foundry Inc., Blaine, MN
Presently, solidifying under gas pressure is a little used yet powerful way to address fundamental quality issues in metal casting.  When that technique is coupled with conductive inert gasses, its effectiveness is increased due to faster solidification times and partial suppression of burning elements in the mold.  This technique works in porous media molds, which includes, but is not limited to sand casting, investment, and lost foam (aka EPC) methods.  In particular, the combined method technique will increase mass feeding, deliver increased mechanical properties, and suppress such problems as metal mold reaction defects.  Properties were shown to increase in the mechanical testing of C355, A356, and A201 alloys in separate cast tensile specimens and those excised from the casting.  Step cone molds were employed to note the effect of pressure and inert gasses on metal mold reaction surface defects and general part quality.  Although solidification under pressure is successfully used in a patented process for EPC, this patent pending process incorporates helium and other gasses along with a novel device for the use in sand casting and investment casting.