鋳物
Online ISSN : 2186-0335
Print ISSN : 0021-4396
ISSN-L : 0021-4396
61 巻, 3 号
選択された号の論文の5件中1~5を表示しています
研究論文
  • 高柳 猛, 片島 三朗
    1989 年 61 巻 3 号 p. 163-170
    発行日: 1989/03/25
    公開日: 2011/08/20
    ジャーナル フリー
      Dissolution of the fused silica. α-cristobalite and α-quartz flour into the alkaline aqueous solution was studied. From the results, the fused silica flour is easy to dissolve into the alkaline solution comparing with the others. Caustic soda is better for the dissolvent of the silica than potassium hydroxide.
      The dissolution rate is lowered by proceeding the crystallization of the fused silica to cristobalite. However, many microcracks generates in the cristobalite layer transformed from the fused silica. The contact area of the silica particle with the dissolvent becomes to spread due to the permeation of the alkaline solution into the cracks. Therefore. the phenomenon of the crack formation is useful for promoting the removability of the ceramic core from the casting.
  • 金 基永, 岡根 利光, 大平 貴規, 鈴木 俊夫, 梅田 高照
    1989 年 61 巻 3 号 p. 171-176
    発行日: 1989/03/25
    公開日: 2011/08/20
    ジャーナル フリー
      Displacement of the solidified shell of AC4C alloy castings and metal mold was measured simultaneously at the early stage of solidification in a rectangular cast iron mold using linear variable differential transformer. As molten metal was poured into the mold, bending of the mold occurred toward the liquid side immediately because of the temperature gradient along the mold thickness. This temperature gradient in the mold, however, decreased with time. Therefore it appeared that distance between two measuring points at mold surface contracted first, and dilatated thereafter. And it was possible to predict this behavior with simply supported elastic beam theory.
      It could be identified that mold and casting moved together after pouring until airgap formed by measuring displacement of casting and mold simultaneously.
      Airgap formation time increased and airgap until final solidification time of casting became smaller with mold preheat temperature.
  • 山本 明彦, 山田 俊宏, 長縄 尚, 名取 達雄
    1989 年 61 巻 3 号 p. 177-182
    発行日: 1989/03/25
    公開日: 2011/08/20
    ジャーナル フリー
      The effect of graphite shape, surface roughness and heat treatment on strength of Ni-P alloy films on cast iron has been studied. The Ni-P alloy films plated were deposited on gray cast iron, nodular cast iron and compared with carbon steel by electroless plating. The plated specimens were evaluated by bending test, hardness measurement and X-ray diffraction. The results obtained here are as fallows ;
      (1) Cracks induced by the bending test initiate near the interface between the plating film and the base metal and propagate into the film in the case of cast irons. In the carbon steel, the origins were observed at the surface of the plating film.
      (2) Strength of plating films were not found to be influenced by the surface roughness under R max 200μm and the thickness of the plating film less than 40μm.
      (3) Heat treatment changed the crystal structure of the plating film. Ni3P, NiP2 and Ni2P were identified as precipitation products in the plating film heated at temperatures higher than 300°C although only (111) plane of Nikel was found in the X-ray diffraction patters of the films heated at temperatures lower than 300°C.
      (4) The precipitation of Ni3P, NiP2 and Ni2P decrease the fracture toughness measured by the identation method and the bending strength of the plating film. However, decreasing the precipitation amount of NiP2 may improve the toughness of the film.
  • 片岡 義博, 樋口 正司, 村井 香一
    1989 年 61 巻 3 号 p. 183-187
    発行日: 1989/03/25
    公開日: 2011/08/20
    ジャーナル フリー
      High manganese cast steel was prepared in a high frequency induction furnace, using steel acrap, ferromanganese and ferrochromium as raw materials. Effects of mischmetal addition on the mechanical properties and cast structure were investigated by measuring the wear resistance and the tensile strength, and the grain size of austenitic structure.
      Results are summarized as follows :
      (1) The addition of 0.01% mischmetal results the highest wear resistance and tensile strength.
      (2) But mechanical properties are gradually lowered with 0.02% mischmetal addition and lowered rapidly with more than 0.05% addition.
      (3) The grain size of austenitic structure becomes finer with increasing mischmetal addition.
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