鋳物
Online ISSN : 2186-0335
Print ISSN : 0021-4396
ISSN-L : 0021-4396
57 巻, 11 号
選択された号の論文の7件中1~7を表示しています
技術報告
  • 徳井 雅昭, 森田 章義, 正岡 利鹿, 太田 厚, 鈴木 育夫, 川野 文生
    1985 年 57 巻 11 号 p. 691-696
    発行日: 1985/11/25
    公開日: 2015/01/27
    ジャーナル フリー
      A vertical type pressure die casting process which is expected to have high accuracy, high reliability and high productivity was developed by the authors on the basis of the squeeze casting process. Aluminum castings made by this process have fine appearance, no internal defect and excellent strength. Heat treatment is possible. The high quality of the products is realized by the monitoring equipment installed in the system. Productivity and cost of this process are comparable to the conventional high pressure die casting process. By using this process, it is possible to manufacture aluminum die castings for pressure-tight parts and high strength components with sufficient reliability which was impossible with the conventional die casting process.
研究論文
  • 三宅 秀和, 岡田 明, 新宮 秀夫, 尾崎 良平
    1985 年 57 巻 11 号 p. 697-703
    発行日: 1985/11/25
    公開日: 2011/11/17
    ジャーナル フリー
      Ribbon samples of Fe-C, Fe-C-Si and Fe-C-P system alloys were prepared by a single roller apparatus for rapidly quenching a metal from the liquid state (splat cooling). Characterization of the ribbon samples was performed by observation of the structure, X-ray diffraction and state analysis of surface. (1) When silicon or phsphorus is added into Fe-C system alloy, the ribon samples have metallic gloss, toughness and continuity. (2) When splat cooling is done in this method, the ribbon samples of Fe-C system is crystalline. Some Nonequilibrium phase (ε phase) appears when Si is contained and amorphous phase is formed when P is contained. (3) A region of high carbon concentration partially exists on the surface of the splat cooled cast iron ribbons and the region contains carbon of different degree of graphitization. This phenomenon is considered to result from exuding of the carbonmicrogroups, assumed to exists in the melts because of the liquid structure of Fe-C system alloy, on the surface of the ribbon.
  • 阿部 利彦, 王 上均, 井川 克也
    1985 年 57 巻 11 号 p. 704-709
    発行日: 1985/11/25
    公開日: 2011/11/17
    ジャーナル フリー
      The effect of heat treatment on the ultrasonic sound velocity in flaky, CV and spheroidal graphite cast iron was investigated and the following results were obtained. (1) Sound velocity in cast iron decreases by heat treatment. The decrease becomes apparent either when heating temperature is higher than the upper eutectoid temperature, heating time is prolonged or cooling is rapid. These effects are more apparent in flaky graphite cast iron than in CV or spheroidal graphite cast iron. (2) The decrease of the velocity is caused by the decrease of the effective area fraction of matrix Aef, as a result of formation of voids and gaps on or in graphite through diffusion of carbon atoms from graphite to austenite. However, the decrease of the Aef below eutectoid temperature is considered to be related to formation of cracks induced by thermal stress and to increase of the amount of graphite during heat treatment. (3) Young's modulus E (kgf/mm2) of a heat treated cast iron is approximated by equation (1) and (2)
          E=21500A'ef+1000(1−Aef) ………… (1)
          A'ef=Aef−x …………………………… (2)
    where A'ef is the effective area fraction of matrix in the heat treated cast iron, Aef is the effective area fraction of matrix in the as–cast state and x is the area fraction of void and crack formed during the heat treatment. These equations are the same as the ones applied to cast iron under stress.
  • 荒瀬 良知, 大浜 信一
    1985 年 57 巻 11 号 p. 711-716
    発行日: 1985/11/25
    公開日: 2011/11/17
    ジャーナル フリー
      Transient thermal change in directional solidification (DS) castings with cylindrical geometries was numerically calculated by finite difference method considering radiation heat transfer. The temperature distribution along the DS ingot center line and outer mold surfaces was experimentally measured to be compared with the calculated values, and the validity of the analysis was confirmed. Together with macrostructural observations at vertical cross sections of the DS ingots, the analysis suggests that liquidus or solidus lines must be maintained horizontal or convex during the entire DS process in order to suppress new grain nucleation at the cooled mold wall, and thus to promote continuous growth of the columnar grains from the chill surfaces.
  • 渕上 正朗, 松尾 勇一, 千々岩 健児, 畑村 洋太郎
    1985 年 57 巻 11 号 p. 717-721
    発行日: 1985/11/25
    公開日: 2011/11/17
    ジャーナル フリー
      Squeezing from the upper side of a sand mold is not an efficient method of compacting the sand in the bottom part of the mold, which is critical to the quality of the casting. On the other hand, bottom squeezing, though efficient for compacting the bottom sand, causes other problems such as necessity of changing pattern plates or difficulty of controlling the squeezing pressure. The authors invented a new molding process named “pattern squeeze molding”, in which the molding sand is squeezed from the both sides, eliminating the problems encountered in the conventional processes. An experiment was made to compare the efficiency of the method with the conventional methods such as jolt-high pressure squeeze or air flow squeeze. It was concluded that the pattern squeeze is more efficient in compacting the mold than the other methods. Results of measurement showed that the distribution of pressure on the pattern faces in the pattern squeeze method is more uniform than that by the head squeezing method.
  • 大塚 芳臣, 前園 敏郎, 高橋 良治, 矢野 満
    1985 年 57 巻 11 号 p. 722-727
    発行日: 1985/11/25
    公開日: 2011/11/17
    ジャーナル フリー
      The prevalent processes to produce pearlitic malleable cast iron are as follows : 1) reheating of black-heart malleable cast iron, oil quenching and drawing. 2) direct oil quenching after the first stage graphitization and drawing. 3) air-cooling after the first stage graphitization and drawing. The authors investigated the influence of these different manufacturing processes on the relationship between several pairs of mechanical properties by “Streufeldanalysis”. It was confirmed that the relationship between Brinell hardness and tensile strength was almost independent on the manufacturing processes. It was, however, not the case with the relation between elongation and tensile strength or Brinell hardness. Elongation of pearlitic malleable cast iron produced by the process 1) was the lowest at each level of tensile strength or hardness, while that by the process 2) was the highest. It was also found that the 99.5%Wu-curve of elongation over tensile strength or Brinell hardness in pearlitic malleable cast iron was lower than the 50%Wu-curve of as cast spheroidal graphite cast iron which the authors obtained earlier.
  • 上田 俶完, 滝田 光晴, 生田 浩之
    1985 年 57 巻 11 号 p. 728-732
    発行日: 1985/11/25
    公開日: 2011/11/17
    ジャーナル フリー
      Austempered bainitic ductile iron exhibits a favorable combination of strength and toughness, and has been successfully applied to parts like chain sprockets, gears and pinions. However, since there have been only few studies on the mechanism of bainitic transformation in cast iron, the desired structure can not be reliably obtained. In this study ductile irons with various silicon content were austempered and the relationship among impact properties, isothermal transformation diagram and quantity of retained austenite was investigated. It was found that the isothermal holding time giving the maximum impact values can be predicted from the Bf point detected by dilatometer at each temperature, and there is a positive correlation between the impact value and the amount of retained austenite. As the silicon content increases, the precipitation of carbide during bainite transformation is suppressed, and the maximum impact value and amount of retained austenite increase. Silicon also reduces the rates of their decrease from the maxima after an excessively long holding time. The retained austenite partially transforms to martensite by holding below −75 degree C, decreasing impact value and increasing hardness.
feedback
Top