The Effect of the Metallic Mold Cooling System on the Solidification Structures and the Mechanical Properties for Al-10%Si Alloy Castings

금형주조한 Al-10%Si합금의 응고조직과 기계적 성질에 미치는 금형의 냉각효과에 관한 연구

This study has been focused on the influence of the metallic mold cooling effects on the solidification structures and the mechanical properties for Al-10%Si alloy castings by the variation of pouring temperatures, metallic mold temperatures and Cooling part of metallic mold. The dendrite arm spacing of Al-10%Si alloy was decreased with increasing cooling rate. In case of bottom cooling of metallic mold, DAS was appeared to be $20-22{\mu}m$ and in the middle cooling, it was increased to $36-40{\mu}m$. The DAS decreased proportionally $with(cooling\;rate)^{-3/2}$ at pouring temperatures $680^{\circ}C$ and $(cooling\;rate)^{-1/2}$ at pouring temperature $760^{\circ}C$, but it was proportionally increased to $(local\;solidification\;time)^{1/2-1/3}$ at pouring temperature $680^{\circ}C$ and $760^{\circ}C$. The maximum tensile strength of Al-10%Si alloy casting was obtained in case of bottom cooling of mold at pouring temperature $680^{\circ}C$ and metallic mold temperature $320^{\circ}C$.