Thermophysical Property Measurements on Mold Materials: Thermal Expansion and Density

摘要

In order to optimize casting processes, computational models of solidification have proven to be very valuable to foundrymen. It is experimentally proven that the casting defects are primarily related to mold properties. During the eutectic growth the temperature rises, which is commonly referred to as recalescence. This has a strong effect on the mold walls, and mold wall movement can occur. The huge pressures generated at this time can block voids if mold is rigid. In green sand molds the moisture content will be reduced and mold wall will expand easily. According to previous research results, a distribution of thermophysical properties of the mold in the mold cavity, and the movement (expansion or contraction) of the mold and the metal interface are crucial for formation of many defects. The thermal expansion and bulk density of selected mold materials (olivine sand and zircon sand) and silica sand cores in transient regimes were determined in this study using a computer-controlled dual-pushrod dilatometer.