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63 巻, 7 号
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研究論文
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大原 伸昭, 加藤 榮一1991 年 63 巻 7 号 p. 581-588
発行日: 1991/07/25
公開日: 2011/07/08
ジャーナル フリーThe effect of the oxidation of Al on the formation of hydrogen blowholes has been investigated by the technique of solidifying molten Fe-C-Si alloys in quartz tubes. In this study, the melts were treated with a gas mixture of H2, Ar and H2O by bubbling through the melts for purposes of oxidizing only Al in the melts. The equilibrium oxygen partial pressure of this gas mixture was established at about 10-14 Pa, and thermodynamic consideration indicated that only Al was oxidized by this treatment. Furthermore, the effects of the addition of very small amounts of Te and Bi on the blowhole formation were also investigated during this study. Results obtained are as follows;
(1) The oxidation of only Al in the melts increased the blowhole occurrence. The same results were obtained in the presence of Ti in the melts.
(2) On condition that only Al in the melts was oxidized, the additions of Te and Bi in very small amounts of about 0.005 % showed a tendency to decrease the blowhole occurrence. As the time goes after the addition of Te and Bi, the formation of blowholes was observed again.
(3) The pressure required to form a hydrogen micropore has been cosidered to decrease on the interface between Al2O3 and the liquid phase. The addition of Te and Bi decreased the content of acid insoluble Al which meant the content of Al2O3. Therefore, the addition of Te and Bi decreased blowhole occurrence.抄録全体を表示PDF形式でダウンロード (805K) -
平塚 貞人, 中村 満, 堀江 皓1991 年 63 巻 7 号 p. 589-594
発行日: 1991/07/25
公開日: 2011/07/08
ジャーナル フリーUsing hypereutectic gray cast iron welding rods coated with 4 kinds of inoculant (Fe-Si, Ca-Si, Ca-Si-Ba and Ca-Si-Ba-Al), spheroidal graphite cast iron were welded by TIG welding process. After welding, microstructures and mechanical properties of weld metal and bonded zone on heat affected zone were investigated. Graphite nodule counts on weld metal were measured and X-ray microanalysis (EPMA) was carried out to detect Mg, S, Ca and Ba in spheroidal graphite. As a result, the Ca-Si-Ba inoculant had the best effect of inoculation of all. At the center of graphite spheroidal, some heterogeneous phases were observed. These phases were composed MgS, CaS and BaS, Graphite nodule counts of weld metal increased with increasing Si in the inoculant, and that was related to the mechanical properties too. Vickers hardness number of weld metal was valued, less than Hv : 350 and tensile strength was 492∼536 MPa. It was found that the weldment had comparatively good strength which is more than ordinary ductile cast iron, but Charpy impact value (unnotched) was 27∼46 J/cm2, which was much lower than that of the base metal.抄録全体を表示PDF形式でダウンロード (763K) -
安江 和夫, 西尾 敏幸, 山田 康雄, 小畑 良洋1991 年 63 巻 7 号 p. 595-600
発行日: 1991/07/25
公開日: 2011/07/08
ジャーナル フリーAn apparatus by using magnetic change was developed for measuring isothermal transformation (IT) diagram. By using the apparatus, the effects of alloying elements and austenitizing conditions on the IT diagram of ductile cast iron were examined. The incubation period of eutectoid reaction became shorter with the longer holding time or the higher holding temperature at austenitizing. Alloying elements can be classified into two groups, acting on the only eutectoid reaction and both the eutectoid and the bainite reactions. Molybdenum extended incubation period at eutectoid reaction, even addition with small amount. Nickel, copper and manganese were also effective for improvement of hardnability, but aluminium injured hardnability.抄録全体を表示PDF形式でダウンロード (692K) -
塩田 俊雄, 松岡 敬, 小松 眞一郎1991 年 63 巻 7 号 p. 601-606
発行日: 1991/07/25
公開日: 2011/07/08
ジャーナル フリーInfluence of manganese content on Charpy impact fracture characteristics of as-cast and ferritic annealed spheroidal graphite cast irons containing manganese from 0.05 % to 0.90 % were investigated in the condition of U-notched and unnotched specimens. With increasing manganese content the impact value in the ductile region decreases and the impact transition temperature increases considerably in both as-cast and ferritic annealed specimens. And also, as the amount of manganese increase, the fraction of brittle fracture increases in the transition region.抄録全体を表示PDF形式でダウンロード (709K) -
笹栗 信也, 松原 安宏, 大城 桂作, 小平 一丸1991 年 63 巻 7 号 p. 607-612
発行日: 1991/07/25
公開日: 2011/07/08
ジャーナル フリーEutectic high chromium cast iron containing 26 % Cr and mild steel were brazed with pure copper filler, and relationships between bonding strength and bonding conditions were investigated. When the assembly of cast iron and steel having copper filler of 18, 35 and 50 μm in thickness was held at 1383 K to 1453 K for 0.6 to 3.6 ks in vacuum of 1.33×10-2 Pa, bonding strength (τB) increased with an increase in both bonding temperature and holding time, and decreased after reaching to a maximum value. Under the same bonding condition, τB lowered as the thickness of filler metal increased. In most of the samples, fracture occurs at different places in the bonded zone. It is considered that bonding strength depends on the microstructure of the bonded zone. On the other hand, rod-like-crystals grew from cast iron to steel in the bonding region. The ratio of the crystal length to the width of bonded zone(GA)increased with an increase in both bonding temperature and holding time, and increased as filler metal thickness decreased. These phenomena fairly correspond with the above mentioned relationships between τB and bonding conditions and filler metal thickness. Therefore, it is found that τB is closely related to GA. Further, it can be said that the decrease in τB may be due to a formation of voids in the bonded zone.抄録全体を表示PDF形式でダウンロード (713K) -
桑野 正司, 大城 佳作, 沢本 章1991 年 63 巻 7 号 p. 613-619
発行日: 1991/07/25
公開日: 2011/07/08
ジャーナル フリーInfluence of 0, 1 and 3 % Mo addition and Cr/C ratio were investigated on hardenability of high chromium cast iron containing 6.6 to 26 % Cr and 1.6 to 3.6 % C by using a dilatometer. The specimens were destabilized at 1173 to 1323 K for 1.2 to 360 ks and then cooled to room temperature at rates ranging from 20 to 0.008 Ks-1 and the continuous cooling transformation diagrams were determined based on their cooling curves and dilatometric transformation curves. Molybdenum showed a little influense on Ms temperature and the hardness of matrix of cast irons quenched after destabilization heat treatment. Ms temperature of homogenized specimen rose with the increase in Cr/C ratio, however the destabilizing temperature for the highest quenched matrix hardness differed depending on Cr/C ratio and Mo content The critical cooling rate of irons destabilized at 1273 K for 6 ks and 360 ks became smaller with the increase in Cr/C ratio and Mo content of cast irons. EPMA analysis revealed that the destabilizing treatment largely lessened Cr and C contents of matrix, but it increased the Mo content slightly.抄録全体を表示PDF形式でダウンロード (882K)
技術報告
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橋本 隆, 片山 博彰, 森川 長, 中川 義弘1991 年 63 巻 7 号 p. 622-628
発行日: 1991/07/25
公開日: 2015/01/22
ジャーナル フリーPDF形式でダウンロード (3968K)
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