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No.2 (1969/04) >

 
Title :金型鋳造鋳鉄の二, 三の性質
Title alternative :Some Properties of Permanent Mold Cast Iron.
Authors :糸村, 昌祐
Authors alternative :Itomura, Shosuke
Issue Date :Apr-1969
Abstract :The object of this study was to investigate tensile strength, hardness, density and wear resistance of the permanent mold cast iron. To carry out this experiment, suitable casting conditions, with which grey iron should be taken in the as-cast condition, were picked out, and the test pieces, JIS 8C type tensile strength test pieces, were casted using two kinds of cast iron mold which has respectively mold ratio 6.5 and 9.0. The mold were coated with two layers of coating material, diatomaceous earth and soot. Irons, about 3kg, were melted in a high frequency induction furnace at about 1450℃ with alumina crucible and were poured into the mold at 1300℃, after being inoculated at 1450℃ with 0.3% Ca-Si. Chemical composition of irons was adjusted to have required the degree of eutectic saturatio (Sc), 0.85 to 1.05, by the addition of low carbon steel to the base iron containing 3.79%C, 2.20%Si, 0.44%Mn, 0.12%P, 0.05%S. For purpose of reference, test pieces with same type were casted into green sand mold. The results obtained are as follows: (1) The microstructure of the permanent mold cast iron with a grey fracture in the as-cast condition is composed of ferritic and pearlitic matrix containing eutectic and fine flaky graphite, and higher Sc is, more the ferrite among the matrix becomes. (2) Strength of the permanent mold cast iron is better than that of the sand mold casting with same Sc:the tensile strength and the hardness of the permanent mold cast iron is respectively 24 to 32kg/mm^2)and 220 to 260 Hv(20).Density of the permanent mold cast iron is higher than that of green sand mold cast iron. (3)In case of grey iron permanent molding,it is necessary to select the chemical composition and the cooling conditions to keep away from tending to be white or mottled cast iron, and hence it tends to have similar structure and mechanical properties. Therefore,it will be recommended,in case of permanent mold casting,to controll strictly the casting conditions using the iron with higher Sc which has less chilling tendency. (4)Owing to the ferritic structure included in the matrix,wear resistance of the permanent mold cast iron is inferior to that of green sand mold cast iron, and higher Sc is, lower the wear resistance becomes.
Type Local :紀要論文
ISSN :0387-429X
Publisher :琉球大学理工学部
URI :http://hdl.handle.net/20.500.12000/23809
Citation :琉球大学理工学部紀要. 工学篇 = Bulletin of Science & Engineering Division, University of the Ryukyus. Engineering no.2 p.13 -25
Appears in Collections:No.2 (1969/04)

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