THE EFFECTS OF FOAM DENSITY AND METAL VELOCITY ON THE HEAT AND MASS TRANSFER IN THE LOST FOAM CASTING PROCESS

摘要

As an innovative technique, the lost foam casting (LFC) process has drawn great attention from both academia and industry in recent years. The key feature of LFC process is that a desired shape pattern made of expandable polystyrene (EPS) foam is buried in unbonded sand and replaced by advancing molten metal. The heat and mass transfer between the molten metal front and the EPS foam pattern plays an important role in the soundness of the product in the LFC process. The present study focuses on determining the characterization of heat and mass transfer during the EPS pattern degradation process. A unique experimental system using a cylindrical quartz window and heated steel block simulating the hot molten metal front has been constructed to make measurements and visualize the process. The foam pattern is 88 mm in diameter and 254 mm long. It is coated twice with DCH Ashland refractory material and the average coating thickness is 1.2 mm. The heat flux and pressure between the moving steel block and the EPS pattern are measured. The process variables studied during this experiment include foam density and steel block speed.