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60 巻, 7 号
選択された号の論文の7件中1～7を表示しています
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研究論文
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東 忠宏, 芦田 経一, 関 保, 横山 久男1988 年 60 巻 7 号 p. 426-429
発行日: 1988/07/25
公開日: 2011/09/08
ジャーナル フリーA furnace 250kg in capacity was developed, in which town gas free from hydrogen is fired. The upper part of the furnace is closed after melt down, the air is preheated by the heat of exhaust gas induced from the upper side, and a temperature sensor for automatic temperature control is immersed in the melt. The surface atmosphere is changed before and after melt down. This furnace ensures the melt to produce sound castings free from gas defects. Working atmosphere is improved, because hot gases are not exhausted from the top of the furnace. The furnace has a heat efficiency for initially charged copper as high as 12% and allows melting time 105min, while the conventional one has only 6% of heat efficiency and allows 170min of melting time.抄録全体を表示PDF形式でダウンロード (644K) -
永井 恭一, 岸武 勝彦, 山下 博史, 大和田野 利郎1988 年 60 巻 7 号 p. 430-435
発行日: 1988/07/25
公開日: 2011/09/08
ジャーナル フリーTensile, three point bending JC and impact tests at different speeds and temperatures were carried out on ferritic-pearlitic and pearlite spheroidal graphite cast irons. The fracture energy per unit volume in tensile test was evaluated as the product of the mean value of tensile and proof stresses multiplied by elongation. It shows the ductile-brittle transition in the same manner as JC and absorbed energies in Charpy test. Acceleration of strain rate shifts transition curves of fracture energy and JC toward the high temperature side, leaving the upper shelf value unchanged. An Increase of pearlite in the matrix also shifts the curves upward, lowering the upper shelf value and moderating the transition curves. Transition temperatures of fracture energy, JC and Charpy absorbed energy are related linearly to the logarithm of strain rate. They rise by about 17°, 19° and 23°C for ferritic, ferritic-pearlitic and pearlitic irons respectively in every tenfold of increase in strain rate.抄録全体を表示PDF形式でダウンロード (667K) -
杉本 繁利, 水野 慎也1988 年 60 巻 7 号 p. 436-441
発行日: 1988/07/25
公開日: 2011/09/08
ジャーナル フリーSpheroidal graphite cast iron was austempered in different conditions for isothermal transformation. The impact characteristics were measured by instrumented Charpy impact test. The impact value of cast iron in the upper bainite transformation region strengthens as the bainite lath spacing decreases and the retained austenite quantity increases. The former is attributed mainly to rise of crack generation load. The latter is attributed to crack generation time and to rise of crack generation load. The impact value of cast iron in the lower bainite transformation region weakens as the iron hardens.抄録全体を表示PDF形式でダウンロード (693K) -
小松 真一郎, 塩田 俊雄, 中村 幸吉1988 年 60 巻 7 号 p. 442-447
発行日: 1988/07/25
公開日: 2011/09/08
ジャーナル フリーFracture toughness tests were carried out on the ferritic spheroidal graphite cast iron containing silicon from 2 to 3.6% in the temperafure range between 20° and −150°C by means of an electric potential method. CT test pieces 15mm in thickness were used. The fracture toughness JIC increases moderately with increase in Si from 2 to 3% , but decreases moderately with increase in Si from 3 to 3.6%. The transition temperature range in which JIC sharply drops by the change of fracture mode from ductile to brittle (clevage) greatly rises with increase in Si. The transition temperature and the lowest temperature of the upper shelf in JIC-temperature curves are lower than those in Charpy impact values. The tendencies mentioned above are also found in macro and micro-fractographies.抄録全体を表示PDF形式でダウンロード (748K) -
桃野 正, 小林 雅之, 及川 和俊, 井川 克也1988 年 60 巻 7 号 p. 448-453
発行日: 1988/07/25
公開日: 2011/09/08
ジャーナル フリーSpheroidal graphite cast iron (FCD) was diffusion bonded to such pure metals as aluminum, oxygen free copper (OFC), tough pitch copper with 390 ppmO (TPC), titanium and nickel with particular reference to the formation of interlayer at the bond interface. The intermetallic compounds of FeAl3 and Fe2Al5 are fromed at the interface in the FCD-to-Al joint. The joint easily ruptures at the Al/FeAl3 interface. The oxides of FeO, Fe3O4 and amorphous SiO2 are formed along the bond interface in the FCD-to-TPC joint, but not formed in the FCD-to-OFC joint. The decomposition of Cu2O into copper and oxygen and the diffusion of oxygen atoms in TPC base metal play an important role in the formation of these oxides. Only TiC is formed along the bond interface in the FCD-to-Ti joint. The FCD-to-Ni joint has an austenitic structure along the bond interface, and a bond strength equivalent to nickel base matal.抄録全体を表示PDF形式でダウンロード (705K) -
桑野 正司, 大城 桂作, 沢本 章, 松田 公扶1988 年 60 巻 7 号 p. 454-460
発行日: 1988/07/25
公開日: 2011/09/08
ジャーナル フリーHigh chromium cast irons containing 15%Cr and 1.8 to 3.4%C were destabilized at 850° to 1,000°C immediately after solidification and were quenched. The precipitation process of secondary carbides and their effects on Ms temperature and the amount of retained austenite were studied. Secondary carbides first precipitate onto eutectic carbides, decreasing Cr and C concentrations in austenite in the vicinity of eutectic carbides and also the segregation ratio of chromium Is defined as a ratio of Cr concentration at the center of primary austenite dendrite to that in the periphery of the dendrite. Is of 1.8%C iron is still larger than 1 and the following precipitation of secondary carbides occurs from the periphery to the center. While the precipitation conversely proceeds from the center to periphery of dendrites in 3.4%C iron having Is less than 1. The nose of TTT curves for precipitation of carbides in austenite lies at temperatures from 850°C to 900°C in all cast irons. Ms temperature rises and retained austenite decreases with the proceed of precipitation.抄録全体を表示PDF形式でダウンロード (823K) -
上田 俶完, 滝田 光晴, 平光 宏行, 安藤 寿明1988 年 60 巻 7 号 p. 461-465
発行日: 1988/07/25
公開日: 2011/09/08
ジャーナル フリーDuctile iron austempered at 400°C for 30min was tensile and compression tested at −196° to 20°C. Changes of retained austenite and Vicker's hardness were measured before and after austempering and tensile and compression testing. The martensite transformation of the retained austenite takes place only slightly under the stress up to the proof stress. But, the retained austenite decreases and hardness increases after failure by tensile stress because of the martensite transformation. The compression stress hinders the martensite transformation, because the transformation accompanies the volume expansion. As the compressive stress and strain are intensified, the transformation of retained austenite is accelerated with a lateral tensile deformation.抄録全体を表示PDF形式でダウンロード (661K)
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