Journal of Japan Foundry Engineering Society
Online ISSN : 2185-5374
Print ISSN : 1342-0429
ISSN-L : 1342-0429
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Volume 69, Issue 8
Displaying 1-9 of 9 articles from this issue
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Research Article
  • Effect of Dissolved Gases on Porosity Formation of Cast Zinc Alloy
    Jiro Yamashita, Makoto Ueda, Norihiko Fukatsu, Teruo Ohashi
    1997 Volume 69 Issue 8 Pages 635-642
    Published: August 25, 1997
    Released on J-STAGE: February 01, 2011
    DOIhttps://doi.org/10.11279/jfes.69.635
    JOURNAL FREE ACCESS
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      Zn-4Al-3Cu-0.05Mg cast alloy is used in mold manufacturing for prototyping, but seldom in mass production due to surface defects. One of its main causes, the effects of dissolved gasses were investigated. The volumetric fraction of porosity in the castings obtained in different gas atmospheres decreased in the following order : oxygen, hydrogen, air, argon. Analysis using galvanic cells based on solid electrolyte and a direct measurement of oxygen potential on solidification indicated that the gas liberated at solidification was not oxygen but hydrogen. The hydrogen content in the molten alloy was also measured by the Telegas measurements and Sievert’s parameter, and it showed a good agreement with that from the volumetric fraction of porosity. It is demonstrated that concentrated hydrogen in front of the fluid-solid interface is one cause of micro-porosity formation.
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  • Effects of Titanium, Zirconium and Sulfur-Manganese on Inter-Graphite Spacing in Unidirectionally Solidified Fe-C Alloy
    Takao Fujikawa, Koukichi Nakamura, Haruyoshi Sumimoto, Shoji Kiguchi
    1997 Volume 69 Issue 8 Pages 643-648
    Published: August 25, 1997
    Released on J-STAGE: February 01, 2011
    DOIhttps://doi.org/10.11279/jfes.69.643
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      The effects of titanium, zirconium and sulfur-manganese on inter-graphite spacing in gray cast iron were investigated by unidirectional solidification Bridgman method. The specimens contain 0.047-0.177mass%Ti, 0.035-0.078mass%Zr, 0.018-0.042mass%S and 0.009-0.14mass%Mn respectively. The specimens are about 80g in weight, 24mm in diameter and 60mm in length. The temperature gradient at the solid-liquid interface is 18-21K/cm. When titanium or zirconium are added to the specimen, the transition rate of the flake-undercooled graphite are shifted to a slower solidification rate. Within the range of this experiment, manganese has no effects on inter-graphite spacing.
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  • Experimental Study of Semi-Solid Die Casting Using Mixture of Elemental Alminum and Nickel Powders
    Toshimasa Morooka, Eiji Yuasa, Chuji Kawamura, Kenji Yoshihiro
    1997 Volume 69 Issue 8 Pages 649-655
    Published: August 25, 1997
    Released on J-STAGE: February 01, 2011
    DOIhttps://doi.org/10.11279/jfes.69.649
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      The effects of mechanical stirring on the semi-solid state of Al-20mass%Ni alloy prepared from elemental powders were examined to obtain information on the semi-solid die casting method using the powder. The structure of the specimen made from unstirred slurry with 15% solid fraction consists of Al3Ni particles, primary Al3Ni phase and eutectic, but a large amount of cored structures containing nickel particles as nucleus was observed for slurry with 38% solid fraction. Stirring the slurry was found to be effective for bringing it to an equilibrium condition of slurry. The Al3Ni particle in the products was found to disperse uniformly when the slurry was stirred. The particle size also increased when the solid fraction of slurry was high.
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  • Relationship Between Load and Deflection in Bending Test of Ferritic Spheroidal Graphite Cast Iron
    Kyoichi Nagai, Toshiro Owadano
    1997 Volume 69 Issue 8 Pages 656-662
    Published: August 25, 1997
    Released on J-STAGE: February 01, 2011
    DOIhttps://doi.org/10.11279/jfes.69.656
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      Tension tests and bending tests using bar test pieces with a square cross section of ferritic spheroidal graphite cast iron were carried out. True stress σt at strain e in tension test can be expressed well by σt = Ken, where K and n denote constants. Bending load P is related well to the deflection at loading point δ as P = Dδn, where D is a constant, the value of which is in good accord with the calculated value. Interrupted bending tests in varied stages reveal that the strain at the bent outer surface is fairly concentrated near the loading point throughout the test, and the deflection δ is proportional to the strain at loading point e0. The slope of test piece at support θ is also proportional to e0. The observed distribution of strain at the bent outer surface along the length of test piece, δ-e0, and θ-e0 relationships in bending deformation are explained pretty well when the shift of neutral plane from the center of thickness is considered.
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  • Three Dimensional Mold Filling Simulation Method Using Non-Orthogonal Element
    Ryougo Kanatani, Itsuo Ohnaka, Jin Dong Zhu
    1997 Volume 69 Issue 8 Pages 663-669
    Published: August 25, 1997
    Released on J-STAGE: February 01, 2011
    DOIhttps://doi.org/10.11279/jfes.69.663
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      The two dimensional mold filling simulation technique proposed in the previous paper has been extended to a three dimensional one. In this technique, which is based on the Direct Finite Difference Method, since the hexahedral elements can be employed, the original shape of a casting can be preserved in its simulation model. The momentum equation is applied in each outer nodal region while the mass conservation equation in the inner nodal element which is the same as the element. Although two dimensionless parameters, βv and βs, are defined to predict the movement of free surface more accurately, a more simple technique for the estimation of βs was used in the three dimensional case. Some numerical mold filling examples showed efficiency and promising results of the proposed technique.
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  • Properties of Surface Coated Iron Castings by Ni and SUS Series Powder Mixed with Low Melting Point Ni Alloy Powders
    Shigenori Tanabe, Kimitugu Yoshikawa, Nobuhiro Nii, Kimio Nakamura, Yo ...
    1997 Volume 69 Issue 8 Pages 670-674
    Published: August 25, 1997
    Released on J-STAGE: February 01, 2011
    DOIhttps://doi.org/10.11279/jfes.69.670
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      The coating on iron castings of thin section (10mm in thickness) was prepared using mixture of Ni and SUS series alloy powders mixed with low melting point powder (Ni-P or Ni-Cr-P alloy powder) as the coating powder on the mold. Several properties of the coated iron castings obtained were tested. The main conclusions drawn were : (1) The best coating layer was obtained by mixed Ni / (Ni-P) = 50/50 powder. (2) The coated iron castings obtained had soft surface layer (100∼200 HV1) containing 10∼20%Ni and therefore good corrosion resistance to spraying of 5%NaCl solution, in comparison with uncoated cast iron. (3) Formation of hard martensitic phase were resulted in the interface of the coating layer and the matrix because of melting of Ni in coating powder to the matrix, which had no influence on spheroidizing of the graphite.
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