鋳造工学
Online ISSN : 2185-5374
Print ISSN : 1342-0429
ISSN-L : 1342-0429
76 巻, 4 号
選択された号の論文の8件中1~8を表示しています
解説
技術報告
研究論文
  • 駒崎 徹
    2004 年 76 巻 4 号 p. 289-295
    発行日: 2004/04/25
    公開日: 2011/02/01
    ジャーナル フリー
      The high vacuum diecasting method developed is gradually being used for new products requiring heat treatment or arc welding. In this study, MIG welding was performed on diecastings, and welding quality which influences internal gas volume of diecastings, electrode wire types were examined.
      When the gas content of diecastings was 1.6 mL/100 gAl, bead surface was excellent for both A4043 and A5356 . At 3.5 mL/100 gAl, bead surface was excellent for the A4043 electro wire. For A5356, considerable smat was generated and bead line was disturbed at 3.5 mL/100 gAl. In the case of Al-Si diecastings, bonding elongation is considerably lower with A5356 wire than A4043 wire. Reasons for brittle welding areas when A5356 is used are because the concentrated blow hole becomes the starting point of cracks and crack formation changes from inside grain to grain boundary.
  • 中江 秀雄, 顧 紅星, 呉 樹森
    2004 年 76 巻 4 号 p. 296-302
    発行日: 2004/04/25
    公開日: 2011/02/01
    ジャーナル フリー
      To produce partially composed metal matrix composites, namely discontinuous MMCs, a spontaneous infiltration process was examined. The preforms of the interpenetrated composites with SiC particles were infiltrated without pressure using cast iron melt. The preforms were fabricated using furan resin and waterglass as the binder containing CuO, Cu2O and Fe2O3 powder for improving their wettability between the melt and SiC preform. As the infiltration process is controlled by a wetting phenomenon, how to improve this infiltration technique based on reactive wetting was investigated.
      The preforms were sintered in a Tamman tube at 1173 K before infiltration. Cast iron sample weighing 40 g was placed on the preform and then infiltrated in air at 1673 K for two hours. The furan resin combined with CuO and Cu2O resulted in complete infiltration without pressure in air at 1673 K. The waterglass combined one was found to be inferior to that of the furan.
  • 趙 柏榮, 上野 勝司, 阿部 隆之, 中江 秀雄
    2004 年 76 巻 4 号 p. 303-308
    発行日: 2004/04/25
    公開日: 2011/02/01
    ジャーナル フリー
      Flake graphite cast iron is a high damping metal. Cast iron is used for engine block and brake materials in the automobile industry due to its low cost and high abrasive characteristics. High drivability characteristics of automobiles such as silence and effective braking ability are becoming more and more important recently. Since the anti-brake squeal materials are therefore needed for the brake materials, we studied the influence of graphite morphology and matrix on the damping capacity of hypereutectic cast iron.
      The results charified that the damping capacity of the cast iron has good correlation with the graphite shape factor Ko, length of periphery of a graphite divided by the square root of the area, and kind of matrix. The damping capacity increases with the Ko value. This means that longer and thinner graphite promotes high damping capacity. Moreover, if the matrix consists of small amounts of martensite and bainite, up to 10%, with pearlite, the damping capacity increases with the fraction of the martensite and bainite.
  • 柏井 茂雄, 大中 逸雄, 木間塚 明彦, 兼吉 高宏, 大道 徹太郎, 朱 金東
    2004 年 76 巻 4 号 p. 309-315
    発行日: 2004/04/25
    公開日: 2011/02/01
    ジャーナル フリー
      To evaluate the accuracy of simulated results of mold filling behaviors in the vacuum suction casting process, mold filling of aluminum casting alloy - AC4C was directly observed by X-ray radiography. A numerical method, in which evacuation of gas through vent hole is taken into account and backpressure of gas is coupled with the pressure field of melt, was applied to simulate the mold filling behaviors Backpressure of gas in the empty mold cavity was also measured by using a semiconductor pressure sensor. The experiments were carried out at two differnt reduced pressures (10 kPa and 20 kPa) and three different reducing pressure rates (1.2 kPa/s, 4.2 kPa/s and 80 kPa/s), which were controlled by the aperture of the valve (in between the gas pipe of the vacuum suction system). Experimental results showed that the effect of reduced pressures and reducing pressure rates on the mold filling behavior were significant. That is the higher the reduced pressures and the reduced pressure rates, the more turbulent the free surface of molten metal, and this resulted in earlier occurrence of the gas entrapments, larger volume of the entrapped gas regions and higher risks of misrun. By comparing simulated results with experimental ones, it was found that good agreement can be obtained in terms of mold filling patterns, positions of gas entrapments and mold filling time. It was also found that simulated results by the conventional method, in which gas evacuation and the effects of backpressure on mold filling are not taken into account, show poor agreement with the experimental ones.
feedback
Top