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33 巻, 2 号
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研究論文
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藤田 修, 久保 陽1961 年 33 巻 2 号 p. 91-99
発行日: 1961/02/25
公開日: 2012/10/29
ジャーナル フリーThe effect of sulphur and manganese on the solidification process was investigated by the quenching method using pure Fe-C-Si alloy. The results obtained are as follows.
(i) On pure Fe-C-Si alloy, the dominating mode of growth of eutectic cell is willow-leaf type austenite which contain flaky graphite in its central rib.
Addition of sulphur to this alloy suppresses the occurrence of willow-leaf austenite and change the graphite to undercooled type.
Addition of manganese to the alloy containnig sulphur promote the willow-leaf austenite with flaky graphite.
(ii) Degree of undercooling and rate of recalescence in the cooling curves of these alloys indicate that addition of sulphur suppresses the occurrence and development of eutectic cell and further addition of manganese diminishes the harm of sulphur.
(iii) The microscopic examination of sulphur prints of samples cooled in furnace or quenched from the stage of eutectic reaction clearly revealed that sulphide inclusion was segregated to the boundary of eutectic cell in the absence of manganese, and addition of manganese decreased the segregation of sulphide. This fact was quite reasonable from the change of type of inclusion from ferrous sulphide to manganese sulphide which was confirmed by the microscopic examinatio under polariged light.
(iv) Contact of graphite with ledeburite in several photographs of samples quenched during eutectic reaction indicates the direct mechanism of graphite formation.抄録全体を表示PDF形式でダウンロード (1393K) -
（アルミニウム合金鋳物の実体試験第2報）森永 卓一, 財満 鎮雄, 高橋 恒夫, 青野 幸雄1961 年 33 巻 2 号 p. 100-106
発行日: 1961/02/25
公開日: 2012/10/29
ジャーナル フリーThe mechanical properties of the various parts of radar hausing made from AC7A are investigated as one of the examination on the aluminium alloy casting in JIS standard, for the purpose of obtaining the data for machine design and production. And, these properties are compared with standard specimens by metal moulding (JIS) and by sand moulding (Federal, USA) both of which cast at the same time. The radar hausing has the more similar feature to that of the sand moulding specimen than that of the metal moulding specimen, yet some differences in properties were found in various parts, caused by the ununiformity of the casting pressure, the difference cooling condition and so on, resulted from the complexity of the shape of the casting.
In this paper, the microscopic structures of the various parts of radar hausing, etched with 0.5% hydrofluoride solution, are examined, comparing the structure of the metal moulding with that of the sand moulding specimen, and above-mentioned facts are ascertined.
The Authors wish to add that this reasearch was subsidized by the Institute of Light Metal Foundation.抄録全体を表示PDF形式でダウンロード (742K) -
河野 良治郎, 奥山 歳生, 福本 桂太郎1961 年 33 巻 2 号 p. 107-112
発行日: 1961/02/25
公開日: 2012/10/29
ジャーナル フリーIn order to design the effective sieves for molding sand preparation, several fundamental factors were obtained by the preceeding experiments reported in 1958.
The purpose of this experiments is to find some factors to design vibrating sieves for practical use.
The sieve in this experiment is the same one shown in the preceeding report, and receiving box is fixed under screen plate having no relation to screen vibration.
Main results obtained are as follow:
1. The sieving volume of sand should be decided by the capacity of vibrator, and the efficiency will decrease when the sand is supied too much or too little.
2. The sand volume and grain distribution sieved by the inclined screen, is not so uniform in all parts of screen area.
The amount of the sand sieved in upper part of screen is far more than that sieved in lower part.
3. The grain size of sand sieved in upper part is much smaller than that sieved in lower part.
4.When, we design vibrating sieves, having no choked grain and to raise the sieving efficiency, it is important to make opening of screen to be larger than required size of molding sand, and to increase the angle of sieve inclination properly.抄録全体を表示PDF形式でダウンロード (581K) -
中井 実, 斎藤 省三, 岡林 邦夫1961 年 33 巻 2 号 p. 113-119
発行日: 1961/02/25
公開日: 2012/10/29
ジャーナル フリーThis report clearify the following facts, concerning the changes -caused by braking- of microscopic structure of brake shoes and tyres. These results were obtained by the observation of the structure just beneath the friction surface of shoes and tyres which had been used for actual servlce.
(1) Changes of the structure were observed within some 100μ beneath the friction surface, and also flowing out of pearlite in matrix and graphite was recognized it. Friction surface was supposed to had been heated up to the high temperature over 800°C by actual braking, for outer layer of some 20∼50μ beneath the surface was seemed to be transformed into martensite.
(2) Wear of brake shoes is promoted by the striping of flowed flaky graphites off the surface.
(3) As to the tyres used for light weight cars, some 50∼100μ thick layers beneath the friction surface were transformed, and thin layers of fine granular peareite had formed on that surface. It means that the tyre surface temperature was raised up to the A1 transformation point.
On the other hand, as to the tyres used for heavy weight cars there have been some 250∼300μ thick transformed layers, and accicular martensite had been found on the tyre surface.
It is because the tyre surface had been heated higher than 800°C and had been tempered by air blast in the case of the braking.抄録全体を表示PDF形式でダウンロード (1151K) -
喜多 新男, 岡倉 常之1961 年 33 巻 2 号 p. 120-131
発行日: 1961/02/25
公開日: 2012/10/29
ジャーナル フリーIt has been empirically known that the tendency of friability of Mold surface at normal temperature does not coincide with the compressive and bending strength of molding sand. The authors have developed a new divice to measure (briefly) the surface stability index (SSI) of molding sand and measured the SSI for several kinds of synthetic molding sand. the results obtained are as follow;
1. The standard sand specimen is shaken for 60 seconds on the 6 Mesh sieve which is agitated by the Ro-tap shaker, then the weight of sand specimen on the sieve is measured.
SSI=W2⁄W1×100% where;
W2 ···········shaken specimen weight (left over)
W1 ···········specimen weight (total)
2. When sand specimens are left in the atomosphere, molding sand more less tendency that the SSI decreares.
3. Dextrin has a greater effect to decrease the drop of SSI than α-starch. α-starch has a little influence upon the SSI of molding sand.
4. Addition of bentonite is more effecitive than addition of fire clay to increase the SSI. Yet fire clay is also considerably effective if good amount is added.
5. SSI becomes higher with finer grain size and higher moisture content.抄録全体を表示PDF形式でダウンロード (1122K) -
大和田野 利郎1961 年 33 巻 2 号 p. 131-136
発行日: 1961/02/25
公開日: 2012/10/29
ジャーナル フリーThe effects of self-chilling fins on the cooling time and the formation of residual stress in silumin and iron framework castings were examined in the same methods as reported previously.
The results obtained are summarized as follows;
1. The solidification periods of silumin castings are effectively shortened by self-chilling fines, and are about 64% in average of those which are expected from the squares of volume to surface area rations.
2. In iron castings the shortening of the transformation periods by fins is very small, and is, −20∼+20% of the expected shortning.
3. In silumin castings the residual stresses of the centre and outer bars are decreased by self-chilling fins, as the sines effectively decrease the temperature differences during the cooling.
4. In iron castings, fines have almost no effect on the residual stresses of the outer bars, though the residual stresses of the centre bars partly decrease.
5. The difference of the effciencies of the self-chilling fines in silumin and iron castings may be attributed, to the large extent, to the difference of thermal conductivities of the castings.抄録全体を表示PDF形式でダウンロード (679K)
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