Casting method
 A consumable pattern of an expanded polyolefin resin and a bulk density of 0.025-0.012 g/cm.sup.3 is embedded in a mold body, a gating system leading to the pattern is formed in the mold body, and molten metal is poured into the gating system to volatilize and replace the pattern. The polyolefin resin is selected from noncrosslinked polypropylene resins, crosslinked polypropylene resins, crosslinked high-density polyethylene and mixtures thereof. 
Japan Styrene Paper Corporation Mitsubishi Jukogyo Kabushiki Kaisha
B
B22C
inventional
Masato Hideki Tadatsugu Teishiro
Naito Kuwabara Hamada Watanabe