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33 巻, 3 号
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研究論文
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喜多 新男, 岡倉 常之1961 年 33 巻 3 号 p. 171-178
発行日: 1961/03/25
公開日: 2012/10/29
ジャーナル フリーIn this report, we discussed the influences of the temperature and humidity upon the surface stability index of molding sand (SSI) and then several testing conditions. The gists of the results obtained are as follows.
1. As to the results of measurement of practical molding sands, there is distinct relationship between the SSI and the atmospheric humidity. Ths lower the humidity is, the lower the SSI of a test piece becomes along with time.
2. In the case of above mentioned sands, there is no constant relationship between the SSI and the atmospheric temperature, 16 to 22°C.
3. Two kinds of synthetic molding sand were tested and it was found the SSI of the dried test pieces (100∼600°C) lowers with a drying temperature. The SSI of American bentonite (Volclay) is lowered less than that of domestic bentonites.
4. By a synthetic molding sand (Base sand; Tokitsu silica sand, Binder; Tokitsu fire clay, Moisture; 4%), the measuring conditions of the SSI were discussed and;
i As to the aperture of sieve, 6 Mesh sieve is suitable.
ii As to the shaking time, one minute is advisable.
iii As to the number of rams, 3 rams (a standard sand specimen's) can be applied.
5. There no constant relationship between the SSI and the surface hardness by a green mold hardness tester.抄録全体を表示PDF形式でダウンロード (766K) -
鈴木 和郎, 山岡 弘1961 年 33 巻 3 号 p. 179-182
発行日: 1961/03/25
公開日: 2012/10/29
ジャーナル フリーWhen the molten metal is poured into mould cavity, the gas is mostly ganerated very suddenly when the molten metal just poured comes into contact with the surface of the mould. As to the interior portion of the mould, however, because of the ill condition for heat conduction of the material mostly used for the mould, it takes some time till a great deal of gas grows from internal portion. Therefore, it is difficult to clarify the mechanism of the growth of blowholes by measuring only the internal pressure of the mould. So, thinking much of the back pressure on the cavity surface of the mould at which molten alloy metal contacts when it is poured, we endevoured to make it easy to meassure this back pressure. This results are as follows :
1) As to the gas generated at the surface of the mould, its back pressure was measured by the inclined tube-type manometer at the points 3 and 5mm apart from the mould surface.
2) The error of the manometer based on the inertia does not appear in the measurement of the velosity under 60mm/s. In this measurement, all of the starting velocity is under 40mm/s.
3) As to the reliability of the measured data, it is recognized that the error of the back pressure is within 10%, by checking the results obtained when the molten metal in 1570°C, was poured into the shell mould with 4% resin several times.抄録全体を表示PDF形式でダウンロード (613K) -
森永 卓ー, 財満 鎮雄1961 年 33 巻 3 号 p. 182-189
発行日: 1961/03/25
公開日: 2012/10/29
ジャーナル フリーThe experiments on the damping campacity of the cast Al-Cu alloys which contain 3.2∼18.6%Cu were cased out in order to find the relationship between the damping capacity and fatigue. The relationship between the damping capacity and Cu content, especially, concerning the influence of Cu in solution upon the properties of the alloy and so on.
The anthors had assumed a close connection between the damping capacity and the fatigue strength mainly on iron and steel, and in this paper, we can see the similar connection in the case of the aluminium cast alloy when the subjected to the torsional fatigue test. That is, the more the damping capacity in torsional oscillation the alloy shows, the greater the fatigue strength becomes, and damping capacity is a lever-relation with fatigue strengh. And as for the influence on Cu content, which is contained near the solubility, the shearing strength and the Knoop ratio achieve maximum value when the Cu is 5.72% and these show the peculiar tendency in the change of property, tensile strength, elongation, hardness (Vickers hardness and Knoop hardness) and the decrement of Harbert's pendulum increase or decrease together with the increase of the Cu content and do not show the maximum or the minimum in the case of 5.72%Cu as long as the torsional angle is small, but, if the torsional angle is large, the damping capacity gradually becomes dercreascent and the peculiar changes in properties are not recognized owing to the appearance of the eutectic phase.抄録全体を表示PDF形式でダウンロード (906K) -
徳永 洋一1961 年 33 巻 3 号 p. 190-201
発行日: 1961/03/25
公開日: 2012/10/29
ジャーナル フリーThe S-curves of Mo-Ni cast irons treated with various alloys or fluxes as graphite spherodizers, were studied. The behavioures of isothermal austenite transformation after austenization at 900°C for 30 minutes were investigated by microscopic examination in pearlite range and by dilatmetric measurement in bainite range. The results obtained were summarized as follows :
1) The S-curve of the magnesium-treated cast iron was not so different from that of the iron treated with the mixture of 4%CaSi, 2%CaF2 and 0.5%MgF2. Thence, it was presumed that the behaviour of austenite transformation was unaffected essentially by residual magnesium.
2) In case of the hypo-eutectic cast iron the pearlite reaction was accelerated slightly, and also the bainite reaction remarkably restrained.
3) It was confirmed that in the nodular graphite cast iron containing high Mo with low Ni the pearlite reaction was retarded, while in iron containing high Ni and low Mo the bainite reaction was restrained remarkably.
4) In the mishmetal-treated iron having quasinodular graphite, the isothermal pearlite reaction was retarded slightly, while the rate of bainite transformation was in the same oder as that of the magnesium-treated iron.
5) By the addition of 6%CaSi together with 2%CaF2, the rates of the second stage graphitization and pearlite reaction were remarkably promoted.
6) When white cast iron treated with magnesium was annealed through the first stage white iron with was through the first stage graphitization, its S-curve moved to the right in pearlite range, but to the left in bainite range as a result of the first bainitic nucleation by very fine graphite.
7) For the Mo-Ni cast iron containing a very small amount of silicon, the transformation product in bainite range was not aciculer ferrite, but similar to that in lower pearlite range.抄録全体を表示PDF形式でダウンロード (1359K) -
堤 信久1961 年 33 巻 3 号 p. 202-209
発行日: 1961/03/25
公開日: 2012/10/29
ジャーナル フリーMany publications have been issued on the mechanical properties of various metals at low temperatures. On the properties of black heart malleable iron, however, no test result was reported except of the works on its impact strength1)2)3)4)5)6)7)8)9)10).
Recently, as the application of this material to various machine and vehicles used in the antarctic area increases, it has become necessary to have the information on the strength of malleable iron at low temperatures. With the view of investigating various mechanical properties of this metal at low temperature, tentile test, bending test, hardness and impact test at temperature from 0 to -196°C were performed. The use of the cooling bath specially designed and made in the author’s laboratory has made it possible to obtain the tensile and bending properties from the specimen immersed in the proper cooling solvent at given temperature.
The results obtained were as follows :
a) Both on the machined and unmachined specimen, tensile and yield strength show no significant change in the range between room temperature to -75°C, and are gradually increased as the temperature below -100°C. The elongation, however, decreases with the temperature decrease.
b) It has been clarified that maximum bending load and the load at yield point show their increase after having their minimum values at -15°C as the temperature decreases.
c) Brinell hardness number increases with the decrease of temperature. Impact strength, however, decreases gradually with the decrease of temperature, and abruptly decreases under the temperature -75°C.
From the results obtained in this work, it can be concluded that when the machine and vehicle having parts consisted of black heart malleable iron are to operate in the extreme low temperature district it is necessary to notice and check at least their impact strength.抄録全体を表示PDF形式でダウンロード (843K) -
中井 実, 岡林 邦夫, 岡見 正一1961 年 33 巻 3 号 p. 209-216
発行日: 1961/03/25
公開日: 2012/10/29
ジャーナル フリーThough the nodular cast iron brake shoes is superior in its charactor of the wear resistance, yet it is inferior because of its low friction coefficient in the braking effect.
In order to improve that defect on the braking effect, we had made the phosphorus-added nodular cost iron brake shoes, and made the experiments on the friction coefficient and the wear resistance of that brake shoes combined with tyre-steel, in both the laboratory and the actual car.
Through these experiments we come to the result that by adding 0.8%P to the nodular cast iron brake shoes, its braking effect is mush improved for practical use.抄録全体を表示PDF形式でダウンロード (1102K)
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