Experimental investigation on ductility and hardness of squeeze cast Al–Si–Cu alloy using response surface methodology and excel-solver

Abstract

Al–Si–Cu alloy oil pump casings used in heavy automotive were produced through gravity die casting process. The customer requirement of 80–125 BHN with a ductility of 3% was not attainable with gravity die casting process. To acquire required level of ductility and hardness, heat treatment process was applied as post-processing, which increases the production cost and time. The squeeze casting technique is a process suitable to enhance the mechanical properties. A set of experiments was designed based on Box-Behnken method of Response Surface Methodology (RSM) to find the optimal parameter settings for squeeze casting process. Squeezing pressure, pouring temperature and dwelling time were considered as process parameters and a model for the process was created. Analysis of variance (ANOVA) results revealed that the model created is acceptable. Excel Solver was used to determine the optimal parameter settings to obtain maximum ductility and hardness. Confirmation tests were carried out to validate settings. The squeeze casting process, with the recommended settings, enhanced the mechanical properties and the heat treatment operation was eliminated.

Keywords

• Al–Si–Cu
• squeeze casting
• ductility
• hardness
• Box-Behnken
• RSM