CONSUMABLE PATTERN MATERIAL FOR CASTING

摘要

PURPOSE:To prevent occurrence of casting defects, to eliminate aftertreatment, and to obtain high quality castings by employing an internal die foamed body of non-bridged polypropylene base resin having a specific density as a consumable pattern material. CONSTITUTION:The internal die foamed body of non-bridged polypropylene base resin having a density of 0.025-0.012 g/cm<3> is employed as a consumable pattern material for casting. The diameter of foamed particles is desirable to be in the range of 0.1-1 mm. An ethylene-propylene random copolymer containing about 0.5-10% ethylene in wt. and other resins are used as the non-bridged polypropylene base resin. That consumable pattern changes into a gas easily when the pattern comes in contact with a poured molten metal because the foamed body has a high decomposition speed. The obtained casting is free from casting defects and internal defects caused by a decomposition gas and has an excellent dimensional accuracy.