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後続誌
58 巻, 11 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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技術報告
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平田 礼次郎1986 年 58 巻 11 号 p. 757-761
発行日: 1986/11/25
公開日: 2015/01/27
ジャーナル フリーOne of the problems to be solved in obtaining press dies or injection dies from zinc alloy precision castings using the ceramic mold process is warping during the casting process. The cause of the warping is supposed mainly to be either one or both of the following two items.
(1) Thermal stress and strain due to unequal temperature distribution and cooling rate in the casting during cooling after solidification.
(2) Localized restraint of casting contraction by the mold during cooling. Two countermeasures to the warping were developed : (1) a controlling system for equalizing temperature in the castings, and (2) introduction of plate-like vacancies into the ceramic molds. The two methods have been successfully applied to the actual production of some large-scaled dies.抄録全体を表示PDF形式でダウンロード (2582K)
研究論文
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岡田 明, 三宅 秀和, 小松 紀仁1986 年 58 巻 11 号 p. 762-767
発行日: 1986/11/25
公開日: 2011/10/25
ジャーナル フリーEutectic and hypoeutectic Al/Si cast alloys were heated to temperature below and above eutectic in either liner or isothermal heating and quenched in ice water and their microstructures were examined. Differential thermal analyses of the alloys during heating were also carried out. By heating the specimen below the eutectic temperature, the lamellar eutectic structure changed to globular one, regardless of silicon content, presumably by dissolution and separation of silicon crystals. This structure change is in close analogy to that of Fe-C alloy. By heating the eutectic alloy to a temperature above the eutectic temperature, the globular Si crystals in eutectic grew into a characteristic angular shape before complete melting. Microstructure of hypoeutectic specimens when heated above the eutectic temperature, changed to a mixture of round primary crystals with random orientation and liquid which appeared as lamellar eutectic when quenched. The crystal often contained a spheroidal liquid at its center.抄録全体を表示PDF形式でダウンロード (939K) -
西崎 泰, 渡辺 久藤, 岡本 常義1986 年 58 巻 11 号 p. 768-774
発行日: 1986/11/25
公開日: 2011/10/25
ジャーナル フリーFluidity of 99.7 percent Al, Al-Cu (up to 10 percent), Al-Mg (up to 10 percent), and Al-Si (up to 20 percent) was measured using a spiral mold. As the mold temperature rises or superheating temperature rises, fluidity as represented by the length of the spiral casting increases, whereas it decreases as the alloying contents are increased in Al-Cu, Al-Mg and Al-Si (up to 9 percent Si) alloys. In the case of Al-9 to 20 percent Si alloy fluidity increases with the increase in Si content.抄録全体を表示PDF形式でダウンロード (735K) -
神戸 洋史, 望月 清範, 阿部 進, 雄谷 重夫1986 年 58 巻 11 号 p. 775-780
発行日: 1986/11/25
公開日: 2011/10/25
ジャーナル フリーFluidity of Cu-8%Sn base ternary alloys containing Si, Al or Fe was measured with spiral shell mold. The alloys showed the minimum fluidity at a dilute concentration of Si, Al or Fe and high fluidity at higher concentration. The metal flows in two different states : complete liquid state and liquid-solid coexisting state. Flow length in the complete liquid state decreases with Si or Al content. It decreases first and then increases with increasing Fe content. When the alloy contains Si or Al, slender dendrites grow and the fraction solid at the flow stop is low at dilute concentration of Si or Al, while it increases at concentration higher than 1 percent, because of rupture of dendrites. When the alloy contains Fe, shorter and rounded dendrites grow and the fraction solid at flow stop increases remarkably. Flow length in the liquid-solid coexisting state depends on the fraction solid at flow stop. Fluidity of the alloys is represented by the sum of the lengths of the above two states.抄録全体を表示PDF形式でダウンロード (596K) -
相馬 詢, 長岡 金吾1986 年 58 巻 11 号 p. 781-786
発行日: 1986/11/25
公開日: 2011/10/25
ジャーナル フリーTo ascertain the growth theory of irreversible graphite migration, two spheroidal graphite irons of coarse and fine graphite nodules from the same melt were heated cyclically in still air and the relation between growth characteristics and change of graphite phase was investigated. Furthermore effect of graphite nodule size on heat resistance of spheroidal graphite iron was discussed from the standpoint of irreversible diffusion occurring during dissolution and separation of graphite. The results obtained were as follows. 1) Growth characteristics of s.g. irons from the same melt depended significantly upon the nodule size. Growth rate of the coarse graphite iron at the maximum was about twice as high as that of the fine graphite iron. 2) By heating the coarse graphite iron number of graphite nodules and ratio of fine nodules in the graphite size distribution increased remarkably. 3) By heating the fine graphite iron ratio of fine nodules decreased and graphite nodules were enlarged. 4) Referring to the growth theory of irreversible graphite migration, the difference of growth characteristics of s.g. irons with different graphite size was attributed mainly to the fact that the distance of carbon diffusion in the austenitic matrix was longer in the coarse graphite iron than that in the fine graphite iron. 5) The effect of graphite size reduction in improving heat resistance of s.g. iron was interpreted by the theory of irreversible graphite migration.抄録全体を表示PDF形式でダウンロード (703K) -
林 清讃, 中田 毅1986 年 58 巻 11 号 p. 787-792
発行日: 1986/11/25
公開日: 2011/10/25
ジャーナル フリーAl-5%Zn-2%Mg alloys with and without an addition of 0.2%Ti, 0.5%Cr or 0.5%Mn were cast in step-shape sand molds, which gave superior mechanical properties to the plate shape castings. Two risering systems were used ; the conventional type (system 1) and insulating type with sleeve and top cover made by ceramic fiber (system 2). With the risering system 1 the Al-5%Zn-2%Mg alloy and the alloy with 0.5%Cr or 0.5%Mn exhibited large shrinkage cavities in the largest thickness part. The average tensile strength of the alloy with 0.5%Cr in the largest thickness part (40mm) was 16.6kgf/mm2 less than that in the thin thickness part (10mm). The average porosity in the former was 3.6% more than that in the latter, suggesting a high section thickness sensitivity. The alloy with 0.2%Ti was little affected by thickness. With the risering system 2 all the alloys showed superior directional solidification. As a result mechanical properties were improved in every section thickness. The improvement was especially remarkable in the alloy with 0.5%Cr. The behavior of the alloy with 0.2%Ti was similar to that with the risering system 1.抄録全体を表示PDF形式でダウンロード (698K) -
二宮 三男, 片島 三朗1986 年 58 巻 11 号 p. 793-797
発行日: 1986/11/25
公開日: 2011/10/25
ジャーナル フリーMold properties of the frozen sand and the green sand at room temperature and elevated temperature were examined. The frozen sand gave higher permability and higher strength than the green sand. Thermal expansion ratio and thermal crack tendency of the frozen sand mold were lower than those of the green sand mold. When cast iron was poured into these molds, thermal expansion of the frozen sand mold was lower than that of the green sand mold and gas pressure in the frozen sand mold rose later than in the green sand mold and the maximum pressure was lower. As a result, scab and gas defects of the test pieces poured in the frozen sand mold were less than those in the green sand mold.抄録全体を表示PDF形式でダウンロード (574K)
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