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32 巻, 7 号
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研究論文
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堀内 薫, 宮坂 知夫, 松井 昭男1960 年 32 巻 7 号 p. 469-475
発行日: 1960/07/25
公開日: 2012/10/30
ジャーナル フリーOn veining tendencies of air setting sands, we have investigated the factors which produced or eliminated veining. Field experiments were carried out on several binders which seemed to be effective in preventing from veining, and its mechanism was studied by measuring the properties of air setting core sand at elevated temperatures. Followings are the summary of the results obtained.
1) Veining is apt to appear at hot spots of cores and the conditions such as the fineness of sands, oil contents, degree of ramming, baking time, pouring temperature, kinds and amounts of binders are considered to be the factors that influence the production of veining.
2) To eliminate of veining practically iron oxide compound is the best binder in the region of our tests, and the amount between, 0.5% and 1.0% is desirable, depending on the thickness of the castings. In this case, however two or three times of ‘accelerator’ content is needed to compensate the decrease of hardening speed. Moreover, 3% of dextrines may be added as secondary binder to gain desirable collapsibility of cores in large castings.
3) It is found that the effective binders promote the deformability of core sand at elevated temperatures, but in this respect it seems that more reliable test methods are needed.抄録全体を表示PDF形式でダウンロード (786K) -
音谷 登平, 徳永 洋一1960 年 32 巻 7 号 p. 476-482
発行日: 1960/07/25
公開日: 2012/10/30
ジャーナル フリーThe S-curve of cast iron is affected by graphite structure and also by special elements such as Ca, Mg, O etc. in it. In order to study the latter factor, the authors investigated the effects of Mg-treatment, vacunm-melting and an addition of Fe3O4 on the S-curve for 0.5%Mo-1.4%Ni cast iron. The behavior of isothermal austenite transformation was studied by the same methods as described in the 1st report. The experiment results obtained were summarized as follows. :
1) The second stage graphitization through direct reaction was remarkably accelerated by Mg-treatment, but restrained by Fe3O4 addition. The indirect graphitization was slightly accelerated by vacunm-melting.
2) The begining point of the upper pearlite transformation was almost unaffected by these various treatments of melt. The ending point was considerbly shortend by Mg-treatment, and prolonged by vacuum-melting as the result of restraining the transformation in matrix of fine eutectic graphite.
3) In the lower pearlite transformation range, the time for begining the transformation was prolonged by Mg-treatment and the time required for its completion was equal for all samples in this work.
4) It was confirmed that Fe3O4 addition showed a strongest tendency to shorten the incubation period and to promote the formation of isothermal bainite in all samples. In the case of vacuum-melting iron, bainite transformation started earlier, but it was found from the dilatation curve that amount of transformation was reduced. By Mg-treatment, the begining line of the S-curve for bainite tranrformation above 300°C was moved remarkably to the right, and also, the Ms-temperature was lowered relatively.抄録全体を表示PDF形式でダウンロード (965K) -
茨木 正雄, 岡本 平1960 年 32 巻 7 号 p. 482-490
発行日: 1960/07/25
公開日: 2012/10/30
ジャーナル フリーThe investigation was performed for purpose of determination of the effect of silicon and manganese on the casting structure of white iron.
The results obtained are listed as follows:
1) The carbide in iron-carbon-silicon alloy containing silicon more than a critical value consists of cementite and a constituent containing silico-carbide. This critical value of silicon content in order to produce the latter constituent decreases with decreasing size of castings. The latter constituent becomes yellow and cementite becomes brown when the polished surface of specimens are heat-tinted.
2) The yellow colored constituent of carbide is located around cementite.
3) The silicon content in the central part of pearite (or matrix) becomes lower than that in the circumference. The heterogeneity of silicon distribution seems to be promoted by rapid solidification of castings.
4) The inoculating treatment caused no appreciable change on the silicon distribution.
5) The number of etching nodules which appear by means of electrolytic etching in the Uhlig electrolyte increases with increasing silicon content or with decreasing size of castings.
6) The number of etching nodules increases with increasing manganese content and becomes maximum at 0.3-0.4% manganese and then decreases.
7) Manganese in white iron has an inclination to produce finer ledeburite and to lower the silicon content required to produce the yellow colored constituent.
8) The more numerous number of etching nodules results, the beter annealability of white iron.抄録全体を表示PDF形式でダウンロード (1093K) -
小川 喜代一1960 年 32 巻 7 号 p. 490-496
発行日: 1960/07/25
公開日: 2012/10/30
ジャーナル フリーIn order to obtain the data on the execllent wear-resistance, I took the study of the sliding wear when the pearlite cast iron is isothermally heat-treated. In other words, the purpose of this study is to make a comparison between the various iron such as heat-treated cast iron, manufactured by General Motors, U.S.A., Meehanite cast iron, acicular cast iron, Ti-eutectic graphite cast iron, Ca-nodular graphite cast iron, engine cast iron of I.L.O. Germany, and the cast iron which was isothermally heat-treated in the structure of abrasion and the amount of wear.
Experiments were made on the lubricating abrasion and the paraffin-60 spindle oil was used as the lubricante under the constant conditions.
The results of the experiments are as follows:
1. The wear resistance of the cast iron isothermally heat-treated decreases remarkably and its mechanical properties are, generally speaking, better than as-cast.
2. The abrasion mechanism of the cast iron which was isothermally heat-treated is, unlike that of the as-cast, similar to the abrasion mechanism of steel, and is greatly relative to toughness and strength. In order to obtain the good results of the abrasion, it is absolutely important to have the cast iron of the great strength by fining the matrix.
3. According to the results gained by the various isothermal heat treatments, the cast iron is good when it is heat-treated at 850°C, and marquenched to 250°C-260°C and tempered to 260°C. Its hardness is about Rockwell “C” 46.
4. According to the isothermal heat treatments, the cast iron expands up to 0.16%-0.25% at the maximum, but this was due to the too big influence of the casting stress, therefore, it is necessaty to anneal the material at low temperature of around 500°C after as-casting, and to eliminate the casting stress.抄録全体を表示PDF形式でダウンロード (964K) -
―キャリヤーガスクロマトグラフ法による―鹿島 次郎, 山崎 卓雄1960 年 32 巻 7 号 p. 497-501
発行日: 1960/07/25
公開日: 2012/10/30
ジャーナル フリーA cast iron sample was set in a quartz tube which was heated to a certain temperature. Argon gas was passed through this tube with c aonstant flow rate and then conducted to the gas chromatographic analyzer where the hydrogen content of the gas was measured each elapsed time. These results were integrated by the planimeter and the total hydrogen content was obtained.
Conditions of measurement were as follows:
1. Cast iron samples were of 10 mm dia. and about 50 mm length.
2. Samples were made by casting into a polished metal mold (cast iron).
3. Samples were polished well by dry emery paper.
4. Samples were put into a desiccator aftar casting and analyzed in 24 hrs.
5. Heating temperature of samples was 650-700°C.
6. Time of extracting hydrogen was about 3 hrs.
7. Flow rate of argon gas was 20 cc/mn when the dia. of the heating tube was 30 mm.
Under the above conditions, the results of the hydrogen determination had a good reappearance.抄録全体を表示PDF形式でダウンロード (629K) -
落合 三雄, 表野 明1960 年 32 巻 7 号 p. 502-514
発行日: 1960/07/25
公開日: 2012/10/30
ジャーナル フリーVarious phenomana has observed by investigating the quatity of centrifugal casting steel as follows.
Segvegation of chemical elements has usually complicated states, but in centrifugal-casting; ① Carbon, silicon and manganese segregates from the centre in the castings to the inside. ② Segregation of phosphor and copper is practically the same in the inside and outside but sulphur segregates in the outside.
Non-metallic inclusions concentrate easily at the part with the form changes suddenly and the part of complicated design, degree of purifying goes down in the part of thin thickness.
Results of investigation, for the causes of crack in the centrifugal casting steel with complicated design are as follows:
① Crack causes easily at low atmorpheric temperature and range of its temperature is below 18°C and 21°C, its range becomes towards high temperature on the castings with complicated design.
② Crack is one which causes at high temperature, Mn% and S% in the molten metal looks to concern with the cracks. Manganese requires mose than 0.75%, Sulphur requires less than 0.012% by considering segregation.
③ As we stated in the item of segregation, undulation of Mn% and S% in the outside looks to concern with th cracks.
④ More or less of non-metallic inclusions has concerned with the cracks and it's cracks resemble closely to the crack by slag.
⑤ Rapid solidifying and cooling rate, accent of revolution per minute and no refuge of thermal stress becomes a cause of the cracks.抄録全体を表示PDF形式でダウンロード (1315K)
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