巻号一覧
後続誌
58 巻, 5 号
選択された号の論文の7件中1～7を表示しています
- |<
- <
- 1
- >
- >|
技術報告
-
岩渕 義孝, 畔越 喜代治, 工藤 博昭1986 年 58 巻 5 号 p. 330-336
発行日: 1986/05/25
公開日: 2015/01/27
ジャーナル フリーWhile 13Cr-4Ni cast steels are widely used for hydraulic turbine runner castings, it had been difficult to reduce phosphorus and sulfur content of these steels because of their high chromium content. Recent advanced ladle refining process and Duplex process have enabled one to obtain heats with P and S less than 0.01 percent. Effects of the two elements on mechanical properties were investigated using specimens taken from a hydraulic runner casting with the following results. (1) Ductility and shelf energy are improved with a decrease of S content, whereas mechanical strength and FATT depend on tempering conditions regardless of S and P content. (2) Lowering P content retards the precipitation of M23C6 carbide in austenite range and consequently suppresses the carbide-induced grain boundary brittleness. (3) Superior toughness and fatigue properties of the 13Cr-Ni steel resulting from low P and S content greatly contribute to safety and reliability of hydraulic runner castings.抄録全体を表示PDF形式でダウンロード (3343K)
研究論文
-
大出 卓, 井川 克也1986 年 58 巻 5 号 p. 337-343
発行日: 1986/05/25
公開日: 2011/10/25
ジャーナル フリーStripe pattern observed in the rapidly cooled cast iron treated with CV graphitizer was investigated. Castings were obtained using several metallic molds or metal-dry sand composite molds. The change of graphite form in the cast iron structure was related to thermal analysis and observation of the top surface of the castings. Namely the resulting CV graphite structure or spheroidized graphite strucutre was related to undercooling of eutectic temperature and the occurrence of shrinkage cavity. Characteristic periodic macrostructure, i.e. stripe pattern, was observed on the longitudinal section of the casting 30mm in thickness treated with CV graphitizer. A layer of CV or spheroidal graphite in pearlite or cementite and that with fine interdendritic graphite in ferrite appeared alternately. The periodic structure was suspected to form by an interaction between cooling effect of the mold and spheroidizing effect of the additive.抄録全体を表示PDF形式でダウンロード (900K) -
山本 志郎, 草野 和宏, 竹林 一成, 田代 康統, 渡辺 司郎1986 年 58 巻 5 号 p. 344-349
発行日: 1986/05/25
公開日: 2011/10/25
ジャーナル フリーNonmetallic inclusions strongly affect the quality of large steel castings. Formation of oxide inclusions is related to the condition of the pouring stream and gating system. Behavior of pouring stream and secondary stream caused by pouring was studied by using water models. It was concluded that the bottom-gating is the best as the basic pouring system for large steel castings.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, 大和田野 利郎1986 年 58 巻 5 号 p. 350-355
発行日: 1986/05/25
公開日: 2011/10/25
ジャーナル フリーThe effects of silicon content and testing temperature on the impact fracture characteristics of ferritic spheroidal graphite cast irons were investigated. V-notched specimens of spheroidal graphite cast irons containing silicon of 2.17 to 7.50 percent were tested by using an instrumented Charpy impact testing machine. The proof stress and tensile strength increase linearly with increasing silicon content in the range of 5 percent or less. Both elongation and reduction of area decrease slightly with increasing silicon content up to 3.5 percent and decline sharply between 4 and 5 percent silicon. The absorbed energy vs. temperature curve shifts to the higher temperature with increasing silicon content. The absorbed energy plotted against silicon content at a given temperature decreases rapidly at a certain critical silicon content, which shifts to the higher silicon side when testing temperature is increased. The fraction of cleavage fracture vs. temperature curve corresponds well to the absorbed energy vs. temperature curve and the energy transition temperature is reasonably consistent with the fracture appearance transition temperature. The ductile-brittle transition temperature rises by about 90 degree C per 1 percent of silicon. The maximum load increases with decreasing testing temperature in the range of ductile fracture and begins to decrease at the fracture transition plastic (FTP) point.抄録全体を表示PDF形式でダウンロード (642K) -
佐野 吉明, 森山 茂樹, 柏井 茂雄1986 年 58 巻 5 号 p. 356-361
発行日: 1986/05/25
公開日: 2011/10/25
ジャーナル フリーMoisture control of molding sand is very important for the quality of castings. Therefore, method of measuring moisture content of molding sand using ultrasonic velosity was examined. Moisture content was adjusted to 3 to 12 percent. Measurement was made on cylindrically shaped remolded sand specimens. Velocity was calculated from the length of the specimen and the time of traveling of ultrasonic wave through it. Effects of remolding pressure, temperature and quantity of bentonite in sand on ultrasonic velocity were studied. Ultrasonic velocity decreased linearly with increasing moisture content in the moisture range studied. It was concluded that application of the method to practice is feasible.抄録全体を表示PDF形式でダウンロード (609K) -
高橋 道夫, 中村 元志, 本間 恭聖, 清水 誠二1986 年 58 巻 5 号 p. 362-368
発行日: 1986/05/25
公開日: 2011/10/25
ジャーナル フリーThis paper presents methods for predicting shrinkage cavity, secondary pipe and porosities in steel ingots with top insulator. Since data on insulator properties, boundary conditions and latent heat, all of which are necessary for calculating solidification process of steel ingots, are lacking, steel ingots were experimentally cast in two different conditions and solidification analysis was made and compared with the first experiment to determine the necessary data. Analysis was then made on the second condition using the data thus obtained. The prediction proved to agree well with measurement on the second experiment. A numerical method of estimating heat transfer coefficient between steel ingot and metal mold using the measured mold temperature change is also proposed.抄録全体を表示PDF形式でダウンロード (665K) -
蘇 國璋, 大中 逸雄, 山内 勇, 岡田 聡, 福迫 達一1986 年 58 巻 5 号 p. 369-375
発行日: 1986/05/25
公開日: 2011/10/25
ジャーナル フリーEutectic nodular cast iron was quenched at various stages during solidification process. Three-dimensional size distribution of nodular graphite in those samples was measured by Lord and Will's method. Solidification of nodular graphite cast iron was numerically simulated using various nucleation models and diffusion controlled growth model. Calculated nodule size and graphite volume fraction by carefully adjusting nucleation frequency constant resultd in the same order of magnitude as those obtained by measurements. However, it was not possible at this stage to obtain agreement on the total distribution curve between experiment and calculation with any of the nucleation model adopted.抄録全体を表示PDF形式でダウンロード (807K)
- |<
- <
- 1
- >
- >|