鋳物
Online ISSN : 2186-0335
Print ISSN : 0021-4396
ISSN-L : 0021-4396
52 巻, 1 号
選択された号の論文の6件中1~6を表示しています
研究論文
  • 生井 亨, 菊地 政郎, 大沢 嘉昭
    1980 年 52 巻 1 号 p. 3-9
    発行日: 1980/01/25
    公開日: 2012/03/28
    ジャーナル フリー
      A laboratory study has been conducted to find out how surface condition affects thermal deformation of permanent mold using test pieces having different properties between the surface and the back. The authors hypothesized that the thermal deformation of such test pieces corresponds to the bending of a composite beam and derived a formula to estimate the magnitude of the thermal deformation of the test piece. The propriety of the formula was examined with the test pieces varying either the elastic modulus or the thermal expansion in the surface. The following relationship existed between the magnitude of thermal deformation calculated from the basic properties of test piece (DC) and the magnitude obtained by the actual test (DA) : DA=0.995DC+0.284 ; (r=0.88). Consequently, it is considered that the characteristics of thermal deformation can be estimated from the basic properties even in permanent mold materials having different surface conditions.
  • 大中 逸雄, 八島 幸雄, 福迫 達一
    1980 年 52 巻 1 号 p. 10-16
    発行日: 1980/01/25
    公開日: 2012/03/28
    ジャーナル フリー
      Influences of radius and effect on solidification of steel plate casting with “L”junction in sand mold were analyzed by the “Matrix Method” (outer nodal point method), which have already been reported by the authors. It was found that the end effect can not be neglected when the length of the casting is less than about four times the thickness of the plate. In castings longer than about five times the plate thickness, which can be regarded as infinite castings, the minimum inside radius at the junction for the hot spot to be located near the geometric center was estimated to be not one time (conventional standard) but from 1.5 to 2.0 times as large as the plate thickness. Furthermore, the section thickness necessary at the junction to make a shrinkage-free junction was calculated and hot tear at the junction was also discussed. It is also estimated that the maximum mold temperature at the junction can be reduced by 20 to 30°C by increasing the inside radius. For these analysis, conventional inscribed circle method and modulus method are not valid and the error in solidification time calculated by these methods reaches upward of 30% in some cases.
  • 大出 卓, 大平 五郎
    1980 年 52 巻 1 号 p. 17-21
    発行日: 1980/01/25
    公開日: 2012/03/28
    ジャーナル フリー
      The solidification behavior on casting iron in metal mold is characterized by fast solidification rate, large supercooling and steep temperature gradient. Metal mold casting structure, which is susceptible to solidification according to the metastable iron-iron carbide system, is ordinarily improved by heat treatment. It is reasonable to make an attempt to minimize or eliminate this treatment process by taking advantage of the self-annealing effect which is obtained by recalescense after supercooling of molten iron in metal mold. A very interesting as-cast structure resulted by obtaining a prominent self-annealing effect during solidification and cooling of molten iron in metal mold selecting carbon and silicon contents as well as the cooling rate. Most effective composition of iron was about 2.9%C and 5.2%Si and cast into water-cooled copper mold 15mm in diameter. The spheroidal graphite structure of this iron without spheroidization treatment was such that the graphite was smaller in size and the nodule number was higher than those of normal ductile cast iron. And moreover, the transition structure of graphite form was observed proceeding from the edge to the center of the specimens.
  • 雄谷 重夫, 戸田 善久
    1980 年 52 巻 1 号 p. 22-27
    発行日: 1980/01/25
    公開日: 2012/03/28
    ジャーナル フリー
      Hot tearing tests were carried out on α- and β-brasses containing elements to form low melting point inclusions such as Pb, Bi and P using a bar-shaped test mold. Si, Sn, Al, Ni and Fe were also added to alter the shape of lead particles and the solidifying structure in leaded β-brasses. Brasses containing Pb and Bi have granular low melting point inclusions and tear before completion of solidification of the primary phase. Brasses containing P have continuous low melting point inclusions along the grain boundary and tear during solidification. The brasses containing Pb and Bi have better resistance to hot tearing than those containing P. Secondary dendrite arms are slenderized and tear resistance is weakened in the β-brasses containing Si, Al and Sn. Fe grain refining successfully intensifies resistance of the leaded β-brasses to hot tearing.
  • 喜多 清, 日野 春樹, 富永 昌武
    1980 年 52 巻 1 号 p. 28-33
    発行日: 1980/01/25
    公開日: 2012/03/28
    ジャーナル フリー
      A study on the characteristics of the frozen mold was introduced to clarify the characteristics of sand bond and to obtain more information concerning the strength of the frozen mold. Scanning electron microscope observation and compressed destructive test were carried out on 50mmφ×50mm sand test pieces which were soaked in liquid nitrogen. In the frozen mold, sand bonds to the frozen moisture coated on the sand surface. The sand bond is firm just like the CO2 process mold. This was indicated by scanning electron microscopy of the bond fracture using Wood's metal replica. The compressed strength of frozen mold is very high, but the strength changes according to the moisture content in the mold and the time soaked in liquid nitrogen. It is possible to make a sound coating by the frozen molding process. Moreover, it is believed that the frozen molding process excels in molding operation, preventing environmental pollution and cutting cost in the foundry shop.
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