Production of rapidly cooled sheet by novel continuous-casting process

Abstract

A novel twin-belt casting device, designed to produce rapidly solidified metallic sheet, is described. A simple computer program was used to predict the effects of the various casting parameters on the cooling rate. Microstructural studies of rapidly solidified lead and lead alloys showed that the effective cooling rate in the sheet was in the range 50–360 Ks⁻¹, in good agreement with that derived from the computer model. Two examples are given of mechanical properties that are altered by virtue of the rapid cooling rate obtained during the casting process. First, plumbers’ solder is shown to be 20% harder after rapid quenching than the same material solidified at 3×10 Ks⁻¹. This is attributed to the enhanced degree of solid solution, and the refined microstructure. Secondly, the room-temperature steady-state creep rate of lead-tin eutectic alloy is compared after both fast and slow cooling from the liquid state. It is shown that rapid cooling leads to an increase in creep rate of over two orders of magnitude; this is attributed to the formation of a fine, random two-phase microstructure rather than the lamellar structure usual after slow cooling.