Experimental investigation and numerical simulation in investment casting

Abstract

An experimental programme to establish shell thermal conductivity and cooling transients in an investment cast part is presented. This showed that shell thermal conductivity is mildly temperature dependent and has a low value, nominally 0.8 Wm⁻¹ K⁻¹. The cooling transients in the cast part were measured with good repeatability and were found to be affected significantly by the addition of forced convection, shell temperature on pour and radiation coupling. Good agreement with an adaptive thermal analysis was achieved using a simple far field radiation model as a basis for establishing heat loss. However, this suggested that the translucent nature of the shell also contributed to heat loss directly from the casting surface.