鋳物
Online ISSN : 2186-0335
Print ISSN : 0021-4396
ISSN-L : 0021-4396
28 巻, 2 号
選択された号の論文の4件中1~4を表示しています
研究論文
  • —Fe-Si,Ca-Siについて—
    牛山 五介, 喜多 新男, 下島 昭二
    1956 年 28 巻 2 号 p. 63-70
    発行日: 1956/02/25
    公開日: 2012/11/09
    ジャーナル フリー
      Many papers have been published on inoculation, but few of them refer the subject of the relation between metals and inoculants.
        The authors made the investigation on this point using commonly used inoculants like Ca-Si and Fe-Si and have made the experiment on the temperature at inoculation, the grain size of the inoculants and its amounts. The results of the experiments concerning this relation shall be announced hereafter.
      1) When the well refined metal containing 1.5%C was used, the inoculating efficieney of Ca-Si was very well at the temperature of more than 1500°C, but below this temperature it was great when Fe-Si inoculant was used.
      2) When the metal of 2.5%C melted by ordinary method was used, the efficiency of inoculation of Ca-Si was much greater than that of Fe-Si even the temperature of the melt was around 1450°C.
      3) The grain size of the both inoculants is preferable as 6∼12 mesh.
      4) The favorable amount of the inoculant is 0.3∼0.5%.
      5) Ca-Si inoculant gives particular effect on the growth of graphite to say nothing of dioxidation.
  • 佐久間 安正, 池田 哲郎
    1956 年 28 巻 2 号 p. 70-78
    発行日: 1956/02/25
    公開日: 2012/11/09
    ジャーナル フリー
      The induction surface hardening of cast iron has been adopted to the industrial use recently, but yet the number of investigations on this subject is very few.
      The authors studied the induction surface hardening of several cast irons such as flaky graphite, finest graphite cast iron inoculated by Ca-Si and two kinds of nodular graphite cast irons ; the one was treated by pure Mg, the other by Ni-Mg alloy.
      The results obtained are as follows : (1) Hardenability and quenched strain of inoculated cast iron are equal to those of nodular graphite cast iron, and the treatment is no difficult. By these reasons, this type of cast iron is very favorable as a heat treatable cast iron in future. (2) The minimum heating time needed for surface hardening of these irons at 15 kw input are respectively 8.5, 5 and 7 sec., inoculated cast iron is most hardenable. (3) As the heating time becomes longer, the surface hardness becomes lower increasing the amount of residual austenite and finally, melting begins at austenite grain boundaries, and cracks are apt to grow tn the melted zone. These phenomena are also occured equally to the case of nodular graphite cast iron. (4) In case of suitable quenching, the matrix of the surface structure is fine martensite and at the inner portion, it becomes finer and it is nearly called hardenite. At the transition layer, incomplete diffused quenching structure or troostite appears mainly around graphite. (5) On heating the nodular graphite cast irons consisted of Bull's eye structure, the diffusion to austenite begins to occur around ferrite structure, and as the temperature reaches higher, it develops inner to inner to the part where ferrite contacts with graphite and the diffusion continues along the boundaries of ferrite grain. (6) It is not the expansion of graphite itself which seems such as the expansion of graphite in the hardening part of flaky graphite cast iron but this seems due to the expansion of shrinkage cavities on heating, and very scarecely, it dues to the expanded shrinkage cavities by quenched stress or micro-crack along graphite.
  • ―竪型乾燥機の試作とその性能―
    河野 良治郎, 奥山 歳生, 鈴木 宗男
    1956 年 28 巻 2 号 p. 79-87
    発行日: 1956/02/25
    公開日: 2012/11/09
    ジャーナル フリー
      Rotary single shaft type, German type of vertical and disc type drying ovens and the like have been used in Japan as drying ovens for sands. But because of the inferior of contact between combustion gas and sands, the efficiency of these types of ovens is very low. Based on the results announced in Repts. 1 and 2, the authors made a new type of drying oven as a trial and shall explain the mechanism and the efficiency of this oven hereafter. This oven is designed applying the air stream drying method and this time the reverse stream system is adopted on drying.
      The structual design of the oven is illustrated in Figs. 1 and 2. The sands slip down onto conical type blades and they are scattered off by rotation. By this rotating action, the sands fall down from all circumferences of the blades and they form the shower of sand grains. Combustion gas forced into the sand shower by means of an exhaust blast machine and this makes the contact between sand grains and hot air stream effectively.
      The sand dried by means of drying ovens heretofore used has a temperature around 100°C.
      If the treated sands have a higher temperature, it seems unfavorable in the point of heat or time lose. To prevent this defect, the cooling air is introduced into the machine from its bottom to cool the heated sands. This is also helpful to lessen the humidity stuffed in the oven. By the effectiveness of the cooling air, the temperature of the sand dried by this oven was about 25°C. The drying efficiency of already existing oven is said about 15∼40% and in the most preferably designed one, it is about 67%.
      But this newly designed oven gives very good result and its efficiency reaches about 69%.
  • —鋳造における湯の流れについて(第5報)—
    千々岩 健児
    1956 年 28 巻 2 号 p. 88-99
    発行日: 1956/02/25
    公開日: 2012/11/09
    ジャーナル フリー
        Cuts and washes which occurred in the vicinity of ingate of a mold and which caused by a high temperature and high speed running of molten metal were studied in this report. In Section 1, the influence of the number of ingates and its shape on cuts and washes was studied and the rate and time of pouring were also studied coating washes on mold surface.
        The relations between the strength of mold and the defects or the relations between the parting easiness and the defects were mentioned in Section 2. The experiment mentioned in Section 2 were carried out without coating any washes on the mold.
        Summarized results taken in Section 1 are as follows.
      1) Cuts and washes occur in front of ingates where the melt runs.
      2) The total volume of cuts and washes is almost equal in every case if the total section area of ingates is equal. When a number of ingates of small size is used and its total section area is constant, the depth of cuts and washes is shallow and the area becomes wider.
      3) The shape of ingate does give little influence.
      4) The relation among three factors such as metal weight to be poured in a unit time M, pouring time T and the total volume of cuts and washes V can be expressed as
                VM1.2T0.
      5) The degree of the occurrence of cuts and washes becomes greater when the pouring temperature is higher or lower.
      6) Factors like moisture and grain size which govern the adhesivility of wash materials, have great influence on the formation of defects and the prefarable moisture content must be choosen and the smaller grain size gives a good result.
      7) Combustibility of washing material gives great effects.
        The results taken from Section 2 are as following.
      8) The degree of cuts and washes has a proportional relation to the easiness of peel-off the facing sand.
      9) Cuts and washes occur in succession of drying the sands in green state after the pouring is made. But in dry molds, they occur immediately after the pouring.
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