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29 巻, 2 号
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研究論文
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橋本 建次1957 年 29 巻 2 号 p. 72-76
発行日: 1957/02/25
公開日: 2012/11/05
ジャーナル フリーIn molding practice of small castings, a vent wire is used to control the permeability of the sand molds. Its quantitative effect, however, is not known, and moreover, there can be seen no pertinent literatures. The purpose of this report is to obtain fundamental data on the vent wire.
The results obtained were as follows :
1) The permeability ratio k before and after insertion of a vent wire is defined as an improvement modulus of permeability. In case of varying insertion depth, the following equation is the relationship between k and diameter D of the vent wire
k=a1+b1D
and in case of varying number of insertion
k=a2−b2/D
2) The following experimental equation is given for k and insertion depth H1
log k=a3−b3H12
and the theoretical equation from consideration of a combined permeability is
{k=H2+H2/α((H1/k')+H2)}
where α is constant. H2 depth not inserted, k' improvement modulus of the permeability in full insertion of a vent wire into a test piece.
3) The following equation is the relation between k and number of insertion N
k=a4+b4 log N
4) The following equation is given for k and permeability K
k=a5−b5 K
where a and b are constants.抄録全体を表示PDF形式でダウンロード (593K) -
―鋳肌の焼着と煮えについて―大平 五郎, 小泉 真人1957 年 29 巻 2 号 p. 76-87
発行日: 1957/02/25
公開日: 2012/11/05
ジャーナル フリーSome fundamental conditions which were responsible for burning and fusion on the casting surface were investigated. Siliceous and natural sand mould with some binders were applied for iron castings, and considerations were done for re-classification of the surface defects.
It was to be noted that there were two kinds of burning − surface peel burning and jumbly lumpy burning. The former appeared in the castings in fine sand mould and often converted into fusion with less refractory sand, while the latter occurred in rather coarse sand connected with metal penetration.
When sand grains were fine, they adhered on metal surface either by oxide or silicate film, and it proceeded to fusion provided circumstances were fabourable to promote silicate formation.
In case of coarse grains, they coagulated each other by silicate binder fused on their surfaces, furthermore, the binder penetrated into voids followed by metal penetration owing to the statical pressure of it.抄録全体を表示PDF形式でダウンロード (1489K) -
―車類のアームに生ずる鋳造応力について（第1報）―小林 昇作1957 年 29 巻 2 号 p. 87-97
発行日: 1957/02/25
公開日: 2012/11/05
ジャーナル フリーWe often encounters with cracks, breakage and deformation in making of castings. And sometimes, these defects are introduced to the castings by a small amount of shock after they are completed.
It is believed that casting stresses occured in castings are responsible for the defects.
This study was conducted with the purpose of finding out the factors by which the casting stresses occur and of contributing to produce quality castings economically.
The shape of the sample to be tested is a wheel like and the experiment was conducted in a working shope.
The factors responsible for increasing casting stresses can be listed as follows :
1) cooling rate of the casting ; for example, the rate is extremely high. 2) moisture content in molds is great. 3) great difference of 5cm (volume/surface area) at different parts of a casting, say, the great difference of cooling rate at the said parts. 4) high hardness value at mold surface.
Annealing the casting is one of the good ways to reduce casting stress whereas high temperature casting is also recommendable.
No remarkable effect of reducing casting stress could be observed with the castings given seasoning treatment for a year.抄録全体を表示PDF形式でダウンロード (933K) -
安田 和夫, 天野 喜一郎1957 年 29 巻 2 号 p. 97-103
発行日: 1957/02/25
公開日: 2012/11/05
ジャーナル フリーSucceeding to the previous report, the segregation in copper alloy castings was studied this time.
The determination of segregation was made by the similar method to the previous experiment, i. e. the local spectrographic analysis. The determinations were made on the samples of 10% Sn-Cu alloy cast into green sand mold and on the samples made of the same alloy treated with zirconium and cast into water-cooled metal and green sand molds respectively.
The gists of the experiments are as follows :
1) Inverse segregation appeared at the outer layer of the sample which was cooled rapidly, disappeared in the sample cooled slowly and which was made of the alloy without zirconium treatment.
2) The grain size of the sample made of the alloy treated with zirconium and slow cooled, becomes very fine and the shape of segregation curve of this sample shows somewhat different type with that of untreated.
3) Neither the grain structure nor the segregation curve of the sample treated with zirconium and slow cooled, show any remarkable difference with these of the sample non-treated. In this report, detailed and theoretical considerations were given to the results mentioned above.抄録全体を表示PDF形式でダウンロード (979K) -
鹿島 次郎1957 年 29 巻 2 号 p. 104-107
発行日: 1957/02/25
公開日: 2012/11/05
ジャーナル フリーAs a testing method of clay content in foundry sand, the method of determining the degree of adsorption by the use of organic colouring matters such as methyl violet and methylene blue has heretofore been used.
This method, however, changes the tone of colour by the sorts of clays, therefore it seems unsuitable testing method for foundry use.
The authors used 1/10 N sulphuric acid solution containing nickel ions instead of using organic colouring matters and made the adsorption test. Satisfactory results have been taken on the relation between green strength of the sand and the clay content in the said sand.抄録全体を表示PDF形式でダウンロード (545K) -
椙山 正孝, 高橋 守雄, 新山 英輔1957 年 29 巻 2 号 p. 108-116
発行日: 1957/02/25
公開日: 2012/11/05
ジャーナル フリーHeat absorbing characteristics of various chills were quantitatively observed by temperature measuring method and their effects on the soundness of castings were discussed. Results obtained were as follows.
(1) Heat absorbing curves of the direct chills were widely affected by the thickness and heat conductivity of the chills. In general, heat absorbing rate of the direct chills was very high shortly after pouring, but was remarkably decreased as temperature of the chills raised near to the heat saturated state. When the chills of same dimension were used, the heat absorbing rate of copper chill was initially higher than that of steel chill, but this tendency is changed inversely as the time elapse. This fact was attributed to the difference of heat conductivity. Therefore, the higher heat conductive chills would not be recommended in the case of the castings which need long pouring time.
(2) When the direct chills of copper or steel were intended to use, their adequate thickness would be able to determine by referring the solidification time curves (Fig. 8) and the heat absorbing curves (Fig. 5, 6).
(3) The heat absorbing ability of the indirect chills was profoundly affected by the thickness of the heat insulating layer between castings and chill surface. Even if the clay film of only 0.1mm thickness was applied, the solidification time of the castings was remarkably prolonged. Sand layer of over 5mm thickness practically eliminated the chilling ability
(4) Specially typed chills, possessing large contacting surface between chills and molds, were studied, and their excellent properties was recognized. These new chills were considered as very useful ones for getting directional solidification.抄録全体を表示PDF形式でダウンロード (832K)
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