EFFECT OF MOLD TEMPERATURE ON HEAT TRANSFER COEFFICIENT AT CASTING-MOLD INTERFACE

16665

The heat transfer coefficient on the casting-mold interface is an important factor which determines the structural and mechanical properties of the casting, and controls the solidification rate of the casting. It is affected by many parameters such as surface roughness, mould material, type of alloy, direction of solidification, mould and casting temperatures, expansion of the mold, contraction of the metal, and air gap on the interface. In this study, it is aimed to investigate the change of the interfacial heat transfer coefficient with temperature of the mold, and to identify the metal-mold interfacial heat transfer mechanisms depending on the temperature of the mold. Timetemperatures relationships were measured with copper chill having different preheat temperatures (323 K, 373 K, and 423 K) in upwards solidifying commercial ETIAL-220 aluminum alloy which is poured at 1023 K. The measured temperatures have been used to determine the effect of mould temperature on the interface heat transfer coefficient. The casting-mold interfacial heat transfer coefficient increased with increasing preheat temperature of the chill (mold). Maximum interface heat transfer coefficients for 323 K, 373 K, 423 K chill temperatures was calculated 12 000 W/m^2 K, 20 000 W/m^2 K and 25 000 W/m^2 K, respectively.

275

Casting , mold interface , heat transfer coefficient , mold temperature

Journal Of The Faculty Of Engineering an‎d Architecture Of Gazi University

282

Journal Of The Faculty Of Engineering an‎d Architecture Of Gazi University