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46 巻, 3 号
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研究論文
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宮沢 信夫, 伊藤 亨1974 年 46 巻 3 号 p. 185-193
発行日: 1974/03/25
公開日: 2012/09/20
ジャーナル フリーThe authors have treated bentonites with several kinds of organic compounds under different treating conditions and investigated the changes in their properties in water. In the present paper, further experiments were carried out on the possibility of applying those organic bentonites which have shown high viscosities in water as a bonding agent of foundry molding sands.
It was found as a result that the bentonites which was treated with certain ionic organic compounds regarded as highly capable of substituting water undergo practically no swelling, whereas the organic bentonites which underwent incomplete adsorption with part of the interlayer water left behind generally lose some of the swelling property but are still hydrophillic. Incomplete adsorption of an ionic organic compound on a bentonite under specified conditions yielded a suspension more stable than that of the bentonite itself. Moreover, some organic bentonites increased viscosity depending upon the adsorption conditions, and it was made clear that there was no distinct relationship between the viscosity and other properties.
Organic bentonites showing high viscosity, particularly those showing high yield values, tend to make the compression strength of foundry molding sands high, and this suggests a possibility of their use as a bonding agent for foundry molding sands.抄録全体を表示PDF形式でダウンロード (806K) -
堤 信久, 作田 庸一, 宮島 定美1974 年 46 巻 3 号 p. 194-202
発行日: 1974/03/25
公開日: 2012/09/20
ジャーナル フリーThe development of automation in foundries at present is outstanding especially in the casting lines including molding and pouring. On the other hand, while the suppression of casting defects is the most important concern in a foundry, the analysis of these defects is dependent upon the experience of the metallurgical engineers and technical consultants in casting. Therefore, if there is a large quantity of defective castings, large man-hours of work must be expended to investigate the cause of the defects.
With a view to speeding up and getting accuracies in the analysis of casting defects, a computer analysis was applied in a foundry. At first, more than two hundred factors which were thought to be the cause of casting defects were extracted from typical characteristic diagrams on various casting defects. After coding these factors, all data were stored in magnetic tapes. When a whole data on casting defects in one foundry were summarized and analyzed, the main cause was analyzed and extracted from the factors' file, utilizing probability number value showing the probability of the cause of each casting defect.
A practical application of the analysis in a commercial foundry for a period of eleven months has certified the practicability of the author's method usiug probability number and detect point. Also the results obtained showed good coincidence with the opinion of technical consultants on the principal causes of casting defects in the foundry.抄録全体を表示PDF形式でダウンロード (847K) -
国安 義明, 上田 勝則1974 年 46 巻 3 号 p. 204-211
発行日: 1974/03/25
公開日: 2012/09/20
ジャーナル フリーThe efficiency percentage of metal in the melting process was about 92% to 97% and the amount of the dross formed was about 2% of melt in industrial zinc die casting plant. The composition of dross formed during melting is closely related to the classification of scraps charged and the quantity of flux. The existence of Fe, Si, O, Cr, Mn and Ca in the dross which was obtained from melt without flux treatment was recognized by the X-ray analysis.
The mechanical properties of alloy ingots reproduced out of the dross which formed in the holding furnace of the hot chamber die casting machine deteriorated due to the decrease in Al and Mg content of the alloy. The mechanical properties of both alloy castings made from the ordinary melt and the melt of plated scraps, which contained 5% of the alloy ingot reproduced from the dross, well satisfied the standard mechanical properties of the material.
It is confirmed that the qualities of zinc die castings were not affected very much under a reliable melt control even when the dross in holding furnace of the hot chamber die casting machine was mixed with the ordinary raw materials within the range of about 5% of the total melt.抄録全体を表示PDF形式でダウンロード (787K) -
上田 俶完, 和出 昇, 川田 昇司1974 年 46 巻 3 号 p. 212-217
発行日: 1974/03/25
公開日: 2012/09/20
ジャーナル フリーThe three dimentional configuration of the incompletely spheroidized graphite cast iron with the ferritic matrix was studied to elucidate the relation between graphite shape and mechanical property. The specimen deeply etched with aqua regia and hydrofluoric acid was observed by scanning electron microscope, and was, also, polished repeatedly and then photographed.
The graphite already branches gradually when the degree of graphite spheroidization is about 40%. The independent spheroidal graphite observed under the normal microscope at this degree of spheroidization was found to be actually a part of a branched graphite. Under graphite spheroidization degree of 40%, the graphite develop continuously into complex shape and the number of cell decreases. The decrease of mechanical properties such as tensile strength, yield strength and, especially, fatigue strength, is assumed to be due to the stress concentrated and the crack propagated through the branched graphites.抄録全体を表示PDF形式でダウンロード (785K) -
田口 一男, 工藤 靖, 増田 喜久男1974 年 46 巻 3 号 p. 218-224
発行日: 1974/03/25
公開日: 2012/09/20
ジャーナル フリーThe purpose of this investigation is to develop a low cost steel casting to be welded to 60kg/mm2-class high tensile steel plates in the cast weld construction of earthmoving machinery.
Manganese, chromium and boron added together were most effective elements for increasing strength economically. The mechanical properties were determined only by the total amount of manganese and chromium. Chromium increased tempering resistance in welding, but 0.90 percent chromium addition markedly decreased toughness at low temperature. The optimum tempering temperature for good ductility and toughness was from 550°C to 650°C. The chemical composition of the newly developed weldable 60kg/mm2-class steel casting is as follows; C : 0.12-0.18%, Si : 0.30-0.60%, Mn+Cr : 1.40-1.70% (provided Cr : 0.30-0.60%), B : 0.001-0.005%.抄録全体を表示PDF形式でダウンロード (1014K) -
宮手 敏男1974 年 46 巻 3 号 p. 225-231
発行日: 1974/03/25
公開日: 2012/09/20
ジャーナル フリーThe effects produced by the addition of various phosphorus and sodium salts on the cast structures of hypereutectic aluminum-silicon alloys were studied. Phosphorus and sodium salts used in this experiment were as follows:
Phosphorus salts; P2O5, H4O2P7, (HPO3)x, AlPO4, (C6H5)3PO4.
Sodium salts; Na2O2, NaOH, Na2CO3, NaHCO3, NaCl.
Sodium phosphates; NaH2PO4·2H2O, Na2HPO4, Na2HPO3·5H2O.
With the addition of any of the phosphorus salts used in this experiment, primary silicon crystals in Al-25%Si alloys were refined. Phosphorus itself occupied about 0.1%, when the amount of phosphorus additives was determined to be sufficient to the hrefinement of primary silicon crystals. With the addition of sodium salts reduced or decomposed by molten aluminum, eutectic structures in Al-Si alloys were modified, but soddium salts such as sodium chloride do not decompose were ineffective for modification.
With the addition of sodium phosphates the primary silicon crystals were refined and at the same time eutectic structures were also modified. The primary silicon crystals and the eutectic structures were improved at the same time with the addition of phosphorus salts and sodium salts. Adequate amounts of salts for the improvement of structures were 0.1% phosphorus and 0.1 to 0.3% sodium.抄録全体を表示PDF形式でダウンロード (1015K)
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