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37 巻, 3 号
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研究論文
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奥本 武臣, 近藤 賢治1965 年 37 巻 3 号 p. 177-185
発行日: 1965/03/25
公開日: 2012/10/11
ジャーナル フリーPrior to malleablizing annealing, the white iron samples were preheated at various temperatures for different hours, and the changes of tensile and impact properties as well as microscopic structures by these treatments were investigated.
The results were summarized as follows; in the case of the samples preheated at 580°C for 10 hours, the size of graphite nodules decreased with their shapes improved, and the ferrite grain sizes decreased. As to the impact transition temperature was lowered by the treatment. Increase of elongation and reduction of area observed in the tensile specimens.抄録全体を表示PDF形式でダウンロード (1010K) -
堤 信久, 野沢 保1965 年 37 巻 3 号 p. 186-193
発行日: 1965/03/25
公開日: 2012/10/11
ジャーナル フリーWith the view of studying the abnormal strucure appearing in the weld bond of black heart malleable iron casting in the case of both electric welding and argon arc welding, argon arc welding with adding tellurium or bismuth to wleding area was performed by using molybdenum electrode at about 500 deg. C. in author's laboratory. The abnormal structure means the micro-structure with messy graphite in ferritic matrix after reheat-treatment of graphitizing.
The results obtained were as followings :
1) The addition of tellurium or bismuth caused to show a pearlitic matrix in welded fusion zone in the annealed specimen. The weld bond, however, shows a ferritic matrix and some groups of structure having messy graphite. Therefore this fact shows that there is no direct relation between fusion zone and weld bond, and then messy graphite was presipitated in the local fusion by affecting of welding heating. These messy graphite structure was precipitated directly from local melts or produced from ledeburitic cementite precipitated in local melt is not clarified in this paper.
2) In a broken tensile spesimen, a fracturing path was occurred along abnormal structure, i.e., the weld bond having messy graphite zone.
3) The abnormal structure showed no effect on tensile strength and Brinell hardness but effected markedly on elongation.
4) The heating rate, cooling rate or holding time in welding would have large influence on this occurence of local fusion in weld bond.抄録全体を表示PDF形式でダウンロード (1015K) -
目黒 博1965 年 37 巻 3 号 p. 193-201
発行日: 1965/03/25
公開日: 2012/10/11
ジャーナル フリーTungsten and tungsten with chrome and copper were added to a molten iron in reducing condition and the iron was cast iron a green sand mould and then the cast structures and mechanical properties were examined. The specimens prepared by this procedure were annealed at 300°, 400° and 500°C for 3 hours and cooled in a furnace. The results obtained were summarized as follows:
1) After adding 0.6∼3.0% of tungsten, 0.2% of chrome with tungsten and 1.0% of copper with tungsten to molten irons, they were poured into sand moulds of different diameters (10, 20, 30, 40 and 50 mm in diameter).
By microscopic observation and hardness measurements, a structural diagram of acicular cast iron was determined.
2) The obstruction of graphitization by tungsten is weak and even in the specimen of 10 mm diameter containig 2.6%C, 1.8%Si and 3.0%W, white iron or mottled iron structure is not appeared.
3) The high quality acicular cast iron has better mechanical properties than plain high grade cast iron. That is, the former has 24∼33 in Rockwell C hardness, 56∼64 kg/mm2 in tensile strength, 910∼1160 kg in bending strength 6.5∼7.5 mm in toughness.
4) The mechanical properties of the acicular cast iron were improved considerably when it was annealed at low temperature such as 300°C for 3 hrs. It showed, 59.5∼74.2 kg/mm2 in tensile strength, 1020∼1450 kg in bending strength 7.0∼9.2 mm in toughness, 26.3∼36.0 in Rockwell C hardness.
5) The tensile and bending strength became lower with the increase of carbon saturation degrees.抄録全体を表示PDF形式でダウンロード (1021K) -
椙山 正孝, 林 清讃1965 年 37 巻 3 号 p. 202-209
発行日: 1965/03/25
公開日: 2012/10/11
ジャーナル フリーVarious properties of the high-aluminum zinc-base alloys are susceptible to the mould conditions or cooling rate as a function of pouring temperature and preheating temperature of the chill mould. This paper describes the effects of cooling rate on various properties of the zinc-22% aluminum eutectoid alloy castings.
When the preheating temperature of the chill mould is elevated from room temperature to 350°C and the metals are poured at 550°C, the tensile strength and hardness fall but the elongation and impact strength rise. The latters contrary fall at the elevated teperature of the chill above 300°C. When the mould temperature is maintained at 100°C and the metals are poured at elevating temperature from 500 to 700°C, little difference is found in the various properties. Pouring at 550°C and preheating of the chill at 100 to 200°C ensure the optimum castings. These castings have relatively excellent properties and stability during aging. They are solidified in the freezing temperature range at the cooling rate 320 to 170°C/min.抄録全体を表示PDF形式でダウンロード (1125K) -
椙山 正孝, 佐藤 純一1965 年 37 巻 3 号 p. 209-216
発行日: 1965/03/25
公開日: 2012/10/11
ジャーナル フリーThe purpose of this work is to clarify the influences of phosphorus and sodium additions upon the cast structures of hypereutectic Al-Si alloys from 15 to 30%Si content. Particular importance is attached to the spheroidizing effect of sodium upon primary silicon crystals and to the correlation between the influence of phosphorus and that of sodium. The experiments involve the microscopic observation of various samples cast in a metallic mould after each treatment, the determination of the relation between the residual contents of sodium and the corresponding cast structures, tensile test and the observation of ruptured samples.
The relation between the residual contents of sodium and the corresponding structures was clearly confirmed. Particulary the spheroidization of primary silicons was kept when the residual content of sodium was more than 200 ppm. In general the tensile strength of this system of alloys was more improved by the simultaneous addition of phosphorus and sodium than by the single addition of phosphorus. And it was also confirmed that the cracking of primary silicon led to the rupture of the whole sample.抄録全体を表示PDF形式でダウンロード (1088K)
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