非鉄純金属の平板鋳物の板厚精度に及ぼす鋳型熱変形の影響

抄録

  The thickness accuracy of plate-shaped pure metal castings was experimentally evaluated, in which the effects of the rmal deformation of molds were also numerically investigated. The plate thickness of the castings made by sand mold casting decreased with the distance from the edge face despite the casting materials and/or casting conditions. The thickness accuracy of these castings could be evaluated using the accuracy index A/T (A : high thickness accuracy range, T : edge thickness), which enabled the quantitative comparison between different casting materials and/or different casting conditions. As a result, the lower the melting temperature, and the higher the superheat and/or mold temperature, the greater was A/T. The thermal stress analysis of the sand mold indicated that the thermal deformation of the mold was the main factor influencing those A/T values. On the other hand, the A/T values of pure tin castings might be greatly affected by thermal and/or solidification shrinkage. The numerical comparison with metal and graphite molds also indicated that the temperature difference caused inside the mold is the main factor influencing the thermal deformation of the mold cavity, and that the deformation is reduced by smaller thermal expansion coefficient and/or greater thermal conductivity (temperature diffusivity) of the mold.