鋳造工学
Online ISSN : 2185-5374
Print ISSN : 1342-0429
ISSN-L : 1342-0429
75 巻, 2 号
選択された号の論文の8件中1~8を表示しています
研究論文
  • 堀川 紀孝, 加野 潤二, 野口 徹, 中村 孝
    2003 年 75 巻 2 号 p. 95-101
    発行日: 2003/02/25
    公開日: 2011/02/01
    ジャーナル フリー
      This paper discusses calculation methods with a two-dimensional model and calculating factors as interfacial heat transfer coefficient and initial temperature in end surface cast-in insertion. In this process, the temperature and solidification progress at the interface in about 100s after pouring are important for the bonding. In calculating these conditions at the interface, it is necessary that the values and boundary conditions used in the calculations are reasonable. In a previous paper, the measured temperatures were used in the calculation as the boundary condltion. To perform realistic calculations with only the initial temperature, interfacial heat transfer coefficients (IHTC) between cast iron melt, sand mold, and steel insert were obtained by temperature measurement and simple inverse method. The calculated IHTC value between melt and mold was 290 W/m2K on the average, and 116 W/m2K at the interface of the insert and mold. There was hardly any difference in the calculated results with the IHTC at the melt-insert interface from 5000 to 12000 W/m2K. These results agreed with the values used in the previous papers. The effects of the initial temperature and IHTC values on the calculated results were also examined.
  • 前田 安郭, 牧野 泰育, 野村 宏之
    2003 年 75 巻 2 号 p. 102-107
    発行日: 2003/02/25
    公開日: 2011/02/01
    ジャーナル フリー
      A three-dimensional simulation model for green sand molding was developed using Distinct Element Method (DEM) in the present study. The characteristics of bonded sand such as sand shape and particle distribution were expressed by the Hard-Core/Soft-Shell model. Contact force and gravitational force moved individual particles. The present model was applied to squeeze molding. Laboratory experiments were carried out to test the validity of the model. Furthermore, two- and three-dimensional simulation using uniformed elements were carried out to compare the compaction behavior. Results of the experiment and simulation clarified the relationship between the void fraction and squeeze pressure during molding. The effects of particle size distribution on sand compaction behavior were also clarified. Mold properties obtained by simulation using non-uniform elements more or less agreed with those by experiments.
  • 前田 安郭, 丸岡 洋介, 牧野 泰育, 野村 宏之
    2003 年 75 巻 2 号 p. 108-114
    発行日: 2003/02/25
    公開日: 2011/02/01
    ジャーナル フリー
      To produce high quality green sand mold, it is necessary to know how green sand particles move during the molding process. A three-dimensional simulation model for green sand molding analysis was developed using a typical discontinuous model, Distinct Element Method. This model is combined with a new algorithm taking the characteristics of bonded sand and particle size distribution into consideration in the simulation. The model was applied to squeeze process simulation using several kinds of green sand. Laboratory experiments were carried out to test the validity of the model. The effect of particle size distribution on sand compaction behavior was clarified from both the experiment and simulation. The mold properties obtained by the simulation more or less agreed with those by experiments. The present study provides new and useful information on the compaction behavior in green sand molding processes.
  • 松浦 清隆, 小柳 貴幸, 工藤 昌行, 呉 長桓, 桐原 聡秀, 宮本 欽生
    2003 年 75 巻 2 号 p. 115-122
    発行日: 2003/02/25
    公開日: 2011/02/01
    ジャーナル フリー
      Two new different methods for coating aluminide intermetallic compounds on metals have been proposed : one is based on exothermic reaction between droplets of aluminum liquid and metal powder, while the other is based on arc surface alloying with aluminide forming metals. The feasibility of the former method was experimentally investigated using NiAl and SUS 316L stainless steel as demonstration coating material and base material, respectively. As soon as an aluminum droplet was dropped onto the nickel powder that had been placed on steel surface, the droplet and powder exothermically reacted and produced a superheated NiAl liquid bead on the steel surface, and the heat of the liquid bead melted the contact surface of the steel. The superheated NiAl liquid bead solidified on the steel surface, leading to NiAl coating on the steel. On the other hand, the feasibility of the latter method was experimentally confirmed by NbAl3 coating on niobium. When tungsten arc was used to melt an aluminum sheet placed on a niobium plate, the niobium surface was also melted and a melt pool of Al-Nb alloy was formed on the niobium plate. The melt pool solidified into layers of niobium aluminides on the surface of the niobium plate, forming a thick NbAl3 layer on the top surface of the niobium aluminides layers.
  • 仲山 公規, 堤 一之
    2003 年 75 巻 2 号 p. 123-129
    発行日: 2003/02/25
    公開日: 2011/02/01
    ジャーナル フリー
      Critical strains during solidification in the continuous casting process for steel were investigated for predicting internal crack formation. The method developed in this investigation is a tensile test on small cylindrical specimens which have been partially remelted using an induction heater. To simulate crack formation in a cast slab, the temperature gradient was applied in the radial direction and the strains were applied perpendicular to the growth direction of the dendrites. The amount of strain applied to the solid-liquid interface was controlled by strain rate and time, and the maximum strain applied to the specimen was up to 2%. From the results of Electron Probe Micro Analysis (EPMA), we found that the segregation of Si, P and Mn which occurred was the same as that found in the cracks in the actual continuous casting process. As a result, the critical strains were found to be 0.2 % for middle carbon (0.16%C) steel.
  • 小林 武, 丸山 徹
    2003 年 75 巻 2 号 p. 130-136
    発行日: 2003/02/25
    公開日: 2011/02/01
    ジャーナル フリー
      The carbon pickup phenomenon in the evaporative pattern casting process was investigated using hypoeutectic cast iron, spheroidal graphite cast iron, cast steel, and high chromium cast iron as Fe-C system alloys. The carbon pickup phenomenon occurred due to thermal decomposition products in front of the melt flow. When the distance of the melt flow was 100 mm, the carbon pickup ratio of hypoeutectic cast iron and high chromium cast iron was more or less maximum. The carbon pickup ratio rose as the carbon equivalent of molten cast iron decreased. In particular, the carbon pickup ratio in cast steel was remarkably high. Conversely, carbon pickup phenomenon did not occur in molten spheroidal graphite cast iron with hypereutectic composition. The carbon pickup ratio increased with an increase in the blended ratio of EPS in the foamed pattern on the hypoeutectic cast iron.
技術報告
  • 津村 治, 吉本 一夫, 山畔 茂
    2003 年 75 巻 2 号 p. 141-147
    発行日: 2003/02/25
    公開日: 2015/01/07
    ジャーナル フリー
      Foundry techniques for large steel casting depends on the skills of foundrymen considerably. Especially, the problem of reducing casting surface defects is difficult to clear numerically. Statistical analysis by using quantification theory for hot tear and sand inclusion, and multiple regression analysis for dimensional defects have been shown to be examples of solving this difficulty.
      Many causes of surface defects can be evaluated by these analyses.
      These evaluations serve as the base data of defect reduction and contribute to the constant improvement of casting quality and quality enhancement activity.
      The system to perform quality enhancement activity was developed and it proved very useful for transfering foundry techniques and skills from the old to young generations.
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