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51 巻, 4 号
選択された号の論文の6件中1～6を表示しています
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研究論文
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津田 昌利, 小林 武, 笠 一也1979 年 51 巻 4 号 p. 189-193
発行日: 1979/04/25
公開日: 2012/06/02
ジャーナル フリーWhen spheroidal graphite cast iron melts were poured into the furan resin mold with para-toluen sulfonic acid as the hardening catalyzer, abnormal structures appeared in the neighborhood of the mold/casting interface. The thermal behavior of the furan mold was studied to see its effect on the appearance of the abnormal structures. Para-toluen sulfonic acid is scarcely contained in the neighborhood of the interface of the furan mold and casting and is released out of the mold system as pyrolytic gas. The pyrolytic gas on the furan mold was analyzed by gas chromatography. As a result, CO, CO2, hydrocarbon system gases and SO2, H2S, (CH3)2S gases were detected. Thus it was surmised that the sulfide gases form the abnormal structures on the surface of castings.抄録全体を表示PDF形式でダウンロード (705K) -
阿部 勝利, 田原 進, 刈米 和夫, 松村 英一, 堤 信久1979 年 51 巻 4 号 p. 194-199
発行日: 1979/04/25
公開日: 2012/06/02
ジャーナル フリーSelf-hardening molding process using polyol compounds and cement was improved. An aqueous solution of polyol compounds (3.5 parts) exhibited excellent adhesiveness when it was admixed with silica sand (100 parts) and small amount of cement (4.0 parts). The mold of this process showed sufficient strength for pouring tests and could be easily broken down by immersing into water, since the polyol compounds markedly inhibited hydration of cement. The mold is not hygroscopic and has good surface stability and collapsibility. The gray iron castings with this mold were sound and the surface looked normal. In addition, this process was free from offensive odor in the mixing and pouring stages.抄録全体を表示PDF形式でダウンロード (729K) -
松田 政夫1979 年 51 巻 4 号 p. 200-205
発行日: 1979/04/25
公開日: 2012/06/02
ジャーナル フリーThe molten metal in the mold flows in different two ways. The molten metal flows inside the metal layers particularly at the tip and flows in contact with the bare surface of the mold remelting solid layers once formed. This report deals with the latter case. If the molten metal flows with a constant velocity in the mold cavity with equal thickness T, the average temperature θm of the molten metal that flows flows t1 seconds behind the tip of molten metal is expressed approximately as follows ;
θm=θp−Mt2/cγT√t1
where θp is the initial molten metal temperature, M is a mold constant, t2 is the running time from the entrance, c is the specific heat and γ is the specific weight of the molten metal. The temperature distribution of the molten metal in the normal direction of metal flow is given by a similar expression. The temperature θ at a distance x from the center is expressed as follows ;
θ=θm+(MT/8λ√t1)(1/3−ξ2)
where λ is the thermal conductivity of the molten metal and ξ is the relative length denoted by ξ=x/(T/2).
Solutions obtained from those approximate expressions were compared with strict Fourier solution under the condition of the constant heat flux. The approximation results and the strict solutions of θm agree precisely, and those of θ agree closely within the range that the dimensionless time (λ/cγ)t2/(T/2)2 is greater than 0.3.抄録全体を表示PDF形式でダウンロード (704K) -
大井 利継, 藤岡 稔1979 年 51 巻 4 号 p. 206-211
発行日: 1979/04/25
公開日: 2012/06/02
ジャーナル フリーIn the case of ordinary gas welding, high temperature preheating to about 500—600°C is generally said to be indispensable in preventing chill formation on freezing. Weld cracking was remarkably affected by the preheating temperature of casting, and is likely to occur by the thermal stress caused by the unevenness of the temperature of casting in preheating or postheating. On the other hand, in the case of modified forehand method which was devised by the authors to prevent chill formation, preheating at such high temperature is not necessary. Therefore, in this case, it is assumed that low temperature preheating to about 300°C is suitable to prevent weld cracking because the localized thermal stress due to temperature gradient in the weld zone can be decreased effectively. Furthermore, in welding tests of actual gray and spheroidal graphite cast irons, it was confirmed that weld cracking seldom occurs by use of the modified forehand method, even when welded without preheating.抄録全体を表示PDF形式でダウンロード (776K) -
片島 三朗, 松浦 正史, 山本 茂昭1979 年 51 巻 4 号 p. 212-216
発行日: 1979/04/25
公開日: 2012/06/02
ジャーナル フリーThe degree of steam flow in the moisture condensed layer of the green sand mold is an important factor, as it controls the latent heat transfer and the steam pressure in the mold. Then, ‘steam permeability’ in the moisture condensed layer was measured by the following method. Steam at 100°C was forced into moisture saturated standard specimen. The difference between the steam pressure in the front and back of the specimen, and the volume of steam passing through the specimen were measured. From these two values, steam permeability was calculated according to Darcy's law. Steam permeability was lower than permeability under constant initial moisture content, and there was little difference between them under the same absolute moisture content. This steam permeability can he used as a fundamental data in obtaining the steam pressure distribution and the migration of moisture condensed layer.抄録全体を表示PDF形式でダウンロード (590K) -
上田 俶完, 新家 光雄, 中尾 吉康1979 年 51 巻 4 号 p. 217-222
発行日: 1979/04/25
公開日: 2012/06/02
ジャーナル フリーWith the aim of forming a molten aluminum corrosion resistant oxide film on the surface of ferrous alloys, commercial pure iron, JIS S45C, JIS SK4, white cast iron, aluminum cast iron and gray iron were dipped in molten pure aluminum and oxidized at high temperature. By this treatment, highly corrosion resistant film against molten aluminum was formed on SK4, white cast iron, aluminum cast iron and gray cast iron. The film was grayish white and was mainly composed of α-Al2O3. In order to obtain a good oxide film, the ferrous alloys must contain adequate quantity of carbon. Dipping at 800°C for 3 min and oxidizing at 800 to 900°C for 4 to 6 hrs are suitable for obtaining the desired result.抄録全体を表示PDF形式でダウンロード (798K)
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