M. moradian, SHAHID BAHONAR UNIVERSITY OF KERMAN, TEHRAN, Iran; G. akbari, SHAHID BAHONAR UNIVERSITY OF KERMAN, kerman, Iran
Cooling slope (CS) casting process was employed in the present work to produce A357 thixoforming feedstock. The dendrites primary phase in the conventionally cast A357 alloy has readily transformed into a non-dendrite by cooling slope casting. The cooling slope is a very simple, compact and cheap piece of equipment with low associated running costs. The primary crystals of test pieces generated in the course of this present study were spherical, and the general morphology of the ingot microstructures, when heated up to semisolid condition, was very similar to the microstructures obtained by conventional semisolid casting routes. In this work we studied on effect of holding time heat treated on microstructure and casting parameters. Primary phase in the ingots thus produced has attained a globular morphology in only as much as 5 min during isothermal holding at 580°C.The perfect spherical microstructure had seen at 25 min holding time at 580°C. The minor effect the pouring temperature and the cooling length had on the CS-cast morphologies was not evident after reheating. Tensile strengths of 225 MPa and 8% elongation were obtained after heat treatment.
Summary: Cooling slope (CS) casting process was employed in the present work to produce A357 thixoforming feedstock.
