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31 巻, 7 号
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研究論文
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岡本 正三, 藤井 資也, 間島 是一1959 年 31 巻 7 号 p. 637-645
発行日: 1959/07/25
公開日: 2012/10/31
ジャーナル フリーSome of the mechanical and corrosion properties of high silicon cast iron bearing small amount of titanium, boron, carbon, copper, nickel or magnesium have been investigated by means of electrical resistance, statical bending test, hardness testing, the estimation of the corrosion loss in various acids as well as the examination of microstructures. The result is as follows.
(1) Existence of α and α’ proposed by professor Ōsawa in 1940 in the iron side of Fe-Si diagram may be supported from the measurement of specific resistance, although the diagram is little noted.
(2) 1%Ti addition in 14∼15%Si-Fe alloys increases the transverse breaking strength, the deflection being not lowered, and improves the corrosion resistance in 5% boiling sulphuric acid. Strengthening, toughening and anti-corrosivility of the alloys due to 0.5%B addition is more significant than those due to 1%Ti. But, addition of 0.5%B causes the inferiority of the corrosion property against hydrochloric acid, and 1%B embrittles the alloy due to the appearance of boron containing compound at the grain boundaries.
(3) Some of the graphite in Fe-Si-C alloys can be spheroidized by Mg-treatment, but the other part of it can not be spheroidized; the appearance of small and flaky graphite at the grain boundaries can not be avoided.
The reason is discussed from its solidification behavior comparing those alloys with common spheroidal graphite iron.
(4) 0.3%Mg-treatment of the molten iron is adequate to improve both the mechanical property and anti-H2SO4 property, 0.5%Mg-treatment being excess.
(5) 1%C, 5∼10%Si alloys treated with 1%Mg in the form of 80Ni-20Mg alloy is shown to have good anti-corrosivility against 10% boiling HCl.抄録全体を表示PDF形式でダウンロード (1075K) -
菊地 政郎1959 年 31 巻 7 号 p. 645-651
発行日: 1959/07/25
公開日: 2012/10/31
ジャーナル フリー(1) Cr content in the cast iron can be greatly increased by melting in a vacuum, without a separation of free cementite or ledebulite, in comparison with melting in a atomosphere.
(2) In both cases of melting in a vacuum and atomosphere, tensile strengths of 8 kinds of cast iron (varied C content from 4.04% to 2.41%) were elevated with decreasing of Sc value; for the same Sc value the tensile strength of vacuum melted cast iron was always about 5kg/mm2 higher than that of atomosphere melted cast iron.
(3) In the cast iron melted in a vacuum, the structure consisted of eutectic graphite and ferrite were in the case of relatively small content of C (e. g. 1.92% 1.60%), while in the steel melted in a vacuum the structure consisted of massive graphite (refined as MG graphite by the author) and pearlite without free cementite.抄録全体を表示PDF形式でダウンロード (1017K) -
―特にその高温の性質について―宮坂 寿雄1959 年 31 巻 7 号 p. 652-659
発行日: 1959/07/25
公開日: 2012/10/31
ジャーナル フリーIn this study, the author announces the results of the experiment which is carried out to investigate the elevated temperature properties of the CO2 sand. Followings are the summary of the results obtained.
1) Above the temperatures of 500°C, the hot strengths of CO2 sand decrease greatly down to less than 1kg/cm2, and the amount of deformation is also great. But, no obvious change in hot strengths can be observed by the change of gassing time.
2) Contrary to the above mentioned result, the retained strengths of the CO2 sand specimens immersed in temperatures higher than 500°C show great increase and this seems to be the main cause of poor collopsibility of CO2 sand.
3) Expansion-contraction curve of the CO2 sand during certain range of soaking time, say, from 30 seconds to 2 minute and a half, shows linear relation irrespective of soaking temperatures (600°C∼1400°C).
4) To increase elevated temperature strength and to decrease retained strength of the CO2 sand, about 2 per cent of additives such as coal-tar-pitch, gilsonite and asphalt emulsion are recommended. Such additives in such additional amount do not seem to give bad influences on expansion contraction characteristics of the CO2 sand.
5) Bentonite or clay addition is not preferable in view of decreasing hot strength, while increasing green and retained strengths of the CO2 sand.
6) The addition of wood flour, cereal or resin binders also seems unpreferable because it gives poor hot strength while increasing deformation of the CO2 sand.抄録全体を表示PDF形式でダウンロード (760K) -
牟田口 元堂1959 年 31 巻 7 号 p. 660-666
発行日: 1959/07/25
公開日: 2012/10/31
ジャーナル フリーThere are many defects in castings which are due to sand mold, and some of them arises from the permeability of sand mold. The permeability of sand mold is different from the permeability which is measured by the testing apparatus, so the relationship between the permeability of sand mold and casting defects can not be inferred by the permeability No. only.
In this report, the author studied the method to measure the permeability of sand mold directly. That is, he determined the pemeability from the equilibrium pressure in mold cavity when a gas was flowed into the mold cavity with a constant rate, Subsequently, the location of gas escape was confirmed by the smoke which is mixed with the gas in the mold cavity.抄録全体を表示PDF形式でダウンロード (745K) -
原田 梅治, 西山 圭三1959 年 31 巻 7 号 p. 667-673
発行日: 1959/07/25
公開日: 2012/10/31
ジャーナル フリーWe investigated the scab and rat tail of gray iron castings with synthetic sand mold. When, where and why do they occur? How do the foundry elements effect them?
The conclusions about these are as follows;
1) The scab and rat tail in synthetic sand mold are occured at the place where the expansion of mold surface was gathered and its deformatiom occured.
Rat tail is the one that its deformation stopped in that condition, and scab is the one that its deformation advanced to breaking up.
2) The more the hot compressive strength increase, the bigger the strain of mold surface is, and scab and rat tail become easy to occur.
3) Other principal factor to break mold surface, is the vapour pressure, and when it is higher than the metal pressure, A-Scab will become B-Scab.
4) Most of scabs in synthetic sand mold occur toward its inside. (from the circumference of the runner of metal)
5) Even in the synthetic sand mold that the scab would occur easily according to the Scab-Factor of AFS Sand Division Committee 8-J, if we have a little moisture and lower pouring temperature, we almost can not find the scab in it.
6) In the result of the expansion test of foundry sand, shock-heated expansion is more similar to the condition of such defect than free expansion.抄録全体を表示PDF形式でダウンロード (958K)
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