Experimental Studies of Interfacial Heat Transfer and Initial Solidification Pertinent to Strip Casting

Abstract

Melt/substrate contacting experiments have been carried out under controlled laboratory conditions designed to approximate the conditions encountered during the initial solidification period in strip casting. Immersion experiments were performed with various substrates embedded in a moving paddle; the substrates had both smooth and textured surfaces. The melt was 304 austenitic stainless steel, and the substrates were made from copper blocks. The apparatus and instrumentation were designed for 'millisecond' resolution of heat transfer behaviour. The experimental variables chosen for study were substrate texture, gas atmosphere, immersion velocity and melt superheat. The conclusions drawn were based on an analysis of transient interface heat fluxes during the first 50 milliseconds of contact, the observed nucleation behaviour and the resultant surface and internal solidification structures. The aim of the work was to add to the fundamental understanding of melt/substrate contacting in the meniscus region, since this will inevitably be critical to strip surface quality.