Permeability of coating in the lost foam casting process

Ann Shing Chang, Teng Shih Shih

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

This study measured the pressures developed during a filling experiment using molten grey iron in the lost foam casting (LFC) process. The measured pressures included back pressure and permeable pressure. The back pressure is created in-mould from the metal-foam interface. The permeable pressure was measured on the mould side of the coating, when gases introduced from the decomposing EPS were permeating through the coating. The permeable pressure reflected the permeability of the coating while filling molten iron. Variables, which included particle sizes, types of binders, weight per cent of binder in coatings, influenced the permeability of coating at room temperature and at casting temperature. Coatings made from flaky alumina developed a greater total length of pore channels than those made from angular silica. Increasing the particle size of the refractory increased the permeability of the coating at room temperature. The highest permeable pressure was measured when the particle size was 74 μm and acrylic resin was used as a binder. The optimum binder content was less than 1% for flaky alumina and acrylic resin binder. The optimum coating thickness was less than 0.5 mm to develop a maximum permeable pressure associated with a minimum back pressure in the mould.

Original languageEnglish
Pages (from-to)263-275
Number of pages13
JournalInternational Journal of Cast Metals Research
Volume12
Issue number4
DOIs
StatePublished - 1999

Keywords

  • Back pressure
  • LFC
  • Permeable pressure

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