Fluidity determination was conducted using silica tube as the fluidity channel and a regulated vacuum system. Fluidity tests were made in which Fe-Si, Ca-Si, Ca-Si-Ba and Ca-Si-Ba-Al were added to hypoeutectic cast iron melt. A linear relation between fluidity length and tube diameter is obtained. Fluidity length increases with increasing suction pressure and with increasing temperature of melt. Fluidity length is propotional to the square root of effective suction pressure. Structure zone of fluidity specimens is classified into three regions from tip backward : ledeburite, mottle and flake graphite structure. The Length of each structure zone increases with increasing suction pressure. Ledeburite structure zone decreases with increasing tube diameter, but the total length of ledeburite zone and mottle zone is constant for increasing tube diameter. Thus, the flake graphite zone increases linearly with tube diameter. With increasing holding time, fluidity length increases up to 10 minutes and then decreases.

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  The fluidity of AC4CH alloy in thin sections was measured using a vacuum fluidity test equipment. Molten metal was drawn into test tubes (of quartz, stainless and copper tube) under carefully controlled conditions. The influence of test variables, such as suction pressures, test tube properties, shielding gases in the test tube and coating of paraffin wax on copper tubes, on the fluidity was examined. The fluidity length increases linearly with increasing tube diameter and with increasing superheat. The fluidity length is proportional to the square root of the effective suction pressure. The fluidity decreases with increasing thermal conductivity of tube material. The fluidity is improved by using paraffin wax coating and by using Argon atmosphere.

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