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30 巻, 2 号
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研究論文
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―割れ破面およびその附近組織の観察結果―沖 進1958 年 30 巻 2 号 p. 83-88
発行日: 1958/02/25
公開日: 2012/11/01
ジャーナル フリーThe author observed many hot-tear fractures and metallographic structures around hot-tears in sand-cast carbon-steel castings containing 0.20∼0.25 % carbon and having wall thickness of 10∼50 mm. The results are summarized as follows :
1. Almost all of the observed hot-tears show indications that they have grown between dendrites of primary crystals including a small amount of liquid metal.
2. The fracture surface of interdendritic hot-tear takes microscopically various characteristic shapes, such as (a) mulberry-like shape, (b) thorny shape, and (c) fin-like shape. The author believes that these shapes all come from dendritic structure of the tear surface and are determined by the relation between the velocity of growth of dendrites and, the velocity of relative motion of tear surfaces moving away from one another.
3. Two or three vein-like segregates described before by K. Singer et al are usually found near each hot-tear. They indicate that the tensile strain of a hot-zone of casting in the later stage of solidification is usually concentrated in a few liquid films.
4. Within the scope of the present observation, hot-tearing is not caused by non-metallic inclusions; it occurs before sulphide inclusions are formed.
5. In a few eases, hot-tearing occurs not between dendrites of primary crystals but on boundaries of primary austenite grains after complete solidification. This kind of hot-tear can easily be distinguished from interdendritic one, and there have been found several sets of conditions for the occurrence of the austenitic hot-tear.抄録全体を表示PDF形式でダウンロード (869K) -
芹田 陽1958 年 30 巻 2 号 p. 88-95
発行日: 1958/02/25
公開日: 2012/11/01
ジャーナル フリーWhen a sulphur refining pot is made of ferro-alloys, it is attacked severely and so the studies were made on the sulphur corrosion of ferro-alloys.
Specimens were made of pure iron, Fe-C alloy and Fe-C-3rd. Elements alloyed specimens, and these were heated with pure sulphur in silica tube. The heating time and temperatures were varied, and the 3rd element is being Cr, Mn, Al or V.
Attacked specimens were cut down and the cut surface was examined by a microscope. The results obtained are as follows :
1. Ferrite was corroded easily but cementite gave a great resistance to corrosive tendency.
2. Specimens added 3rd element showed a great resistance to corrosion but specimens added Mn were relatively liable to corrode.
3. Corroded layers were devided into two layers. Grains in the outer layer were coarsened and arranged vertically to the surface of specimens while grains in the inner layer were put at random and the grain size was finer than that in the outer layer.
4. Cr or Al content differed widely in the outer and inner layers (though fewer in the outer layer) when Cr or Al as the 3rd element was added.抄録全体を表示PDF形式でダウンロード (1223K) -
―炉内の風の流れに関する考察―石野 亨1958 年 30 巻 2 号 p. 95-103
発行日: 1958/02/25
公開日: 2012/11/01
ジャーナル フリーThe purpose of this investigation is to know the fundamental knowledge of cupola operation, through surveying the relation between its construction or something else of cupola and the reactions in furnace, and also through surveying the effects of these factors upon the conditions of melting in furnace.
In order to know the type of air flow blown from the blast pipe and pressure drop in furnace, various surveys were made by using a simple cylinder and a midget cupola. And besides, consideration about air flow in furnace was made with applying fundamental equation which was established by inducing the Bernoulli's theorem into the Sobri Ergun's equation concerning to blast furnace and cupola :
ΔP=√Pe2+5.9×10-6{(1−ε)⁄ε3)}{(t−460)⁄520)}(Q0⁄Aα)H⁄DP −Pe
That proved to agree with the results of author's experiments.抄録全体を表示PDF形式でダウンロード (831K) -
鹿島 次郎, 宮崎 和也1958 年 30 巻 2 号 p. 104-107
発行日: 1958/02/25
公開日: 2012/11/01
ジャーナル フリーThe authors tried to find out the relationship between the packing properties and the grain size distribution of a molding sand, keeping the degree of ramming constant. And found out that a maximum packing property, was obtained when the mixing ratio in weight of two different sands− those are coarse and fine grain size of uniform sands− was 4 : 6.
And also, the more difference in mesh number existed between coarse and fine sands, the more packing property was obtained.
The packing properties of sands are also influenced by the sorts of binders, that is, the packing property of sands bonded with linseed oil is always greater than that of sands bonded with water under the same condition. It is the matter of course that the weights of linseed oil and water to be added to the sands are same.抄録全体を表示PDF形式でダウンロード (556K) -
―砂型中での液体金属の滲透速度―大和田野 利郎, 三ケ島 秀雄1958 年 30 巻 2 号 p. 108-113
発行日: 1958/02/25
公開日: 2012/11/01
ジャーナル フリーThe velocity of metal penetration in sand mould is investigated, by contacting the sand specimen to the surface of molten lead and tin, which are kept at constant temperatures, and applying negative pressure to the specimen for penetration. The sand specimen is prepared by baking sieved silica sand mixed with linseed oil as a binder, The results are as follows :
1. The depth of metal penetration, x, is related to the time of penetration, t2 as
x=α√t+β
where α and β are constants.
2. The coarser the sand and the larger the penetration pressure, the larger the β. The effect of penetration pressure on β is large in coarse sand.
3. α, which determines the velocity of penetration, is independent of the size of sand grains and penetration pressure, but dependent of the temperature of the metal to penetrate, i. e., the higher the metal temperature, the larger the α.
4. αs obtained by experiments are much larger than those expected by previous investigators. This discordance is attributable to the large heat conductivity of the penetrated zone in comparison with that of the sand. The results of calculation of α, in which the thermal constants of penetrated zone and the sand are used, are in better accordance with the αs obtained by the experiments.抄録全体を表示PDF形式でダウンロード (797K)
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