PERSPECTIVES OF COOLING SLOPE METHOD FOR SSF TECHNOLOGY

Abstract

At present, the common techniques existing for large scale creation of semisolid slurry are mechanical stirring, electromagnetic stirring, etc. These suffer from problems like complex design, high cost, structural inhomogeneity and low efficiency. The cooling slope is treated to be a simple but effective method on account of its simple design and easy control of process parameters, low equipment and running costs, high production efficiency and reduced inhomogeneity. With this standpoint, the primary objective of the present research is to describe a cooling slope setup for experimental investigations of slurry and cast billets. In most casting applications, dendritic microstructure morphology is not desired because it leads to poor mechanical properties. Forced convection is one of
the means to suppress these dendrites which flow away to form slurry. This slurry, consisting of rosette or globular particles, provides less resistance to flow even at a high solid fraction and can easily fill the die-cavity. The stated principle is the basis of a new manufacturing technology called “semi-solid forming” (SSF), in which metal alloys are cast in the semi-solid state. This method has several advantages over other prevailing commercial casting methods, such as decrease of macrosegregation, decrease of porosity and little forming dynamisms.