Optimization of squeeze casting process parameters using Taguchi analysis

Squeeze casting is a hybrid metal forming process combining features of both casting and forging in one operation. This paper reports a research in which an attempt was made to prepare solid cylindrical components of LM24 aluminum alloy through squeeze casting. The primary objective was to investigate the effect of process parameters on the mechanical properties exhibited by the castings produced though squeeze casting process. A set of trials were conducted based on parameters settings suggested in Taguchi’s offline quality control concept. The experimental results indicate that the squeeze pressure and the die-preheating temperature were the parameters making significant contribution toward improvement in mechanical properties of squeeze cast LM24 aluminum alloy.

The automotive and aerospace industries have been driving research communities to search for materials with improved mechanical properties and new casting processes [Vijian P, Arunachalam VP (2005) Experimental study of squeeze casting of gunmetal. J Mater Process Technol 170:32–36]. Conventional casting process cannot produce parts as strong as forged parts. The major drawback of casting processes is the formation of casting defects such as porosity, segregation, hot tears etc. [Yue TM, Chadwick GA (1996) Squeeze casting of the light alloys and their composites. J Mater Process Technol 58: 302–307 |  Ghomashchi MR, Vikhrov A (2000) Squeeze casting:an overview. J Mater Process Technol 101:1–9 |  Kleiner K et al (2002) Microstructure and mechanical properties of squeeze cast and semi-solid cast Mg-Al alloys. J Lht Met 2:277–280]. A distinctly different approach to component making is possible with squeeze casting, an emerging metal forming process. The major advantage of this process is its ability to eliminate microporosity to provide isotropic properties and minimize component machining [Brown JR, Barlow J et al (1994) Second report of Institute working group T20 casting process. Foundryman 87:386–390 | Morton JR, Barlow J (1994) Squeeze casting from a theory to profit and a future. Foundryman 87:23–28]. This process has been applied on a wide range of metals, ranging from low melting alloys of lead and zinc to high melting alloys of iron and nickel. Most of the studies concentrated on aluminum and magnesium alloys for light weight components to enhance fuel efficiency. Squeeze casting accounts for 15 to 40% improvement of the mechanical properties than gravity die casting [Yong MS, Clegg AJ (1999) Evaluation of squeeze cast magnesium alloy and composite. Foundryman, pp 71–75]. 

Lynch et al. have carried out investigations with squeeze casting of aluminum and presented various aspects of the process [Lynch RF, Olley R et al (1975) Squeeze casting of aluminum. AFS Trans 122:569–576]. Yue studied the process parameter of squeeze casting and reported that too high pouring temperature and pressures were undesirable as these will lead to poor tensile properties [Yue TM (1997) Squeeze casting of high strength aluminum wrought alloy AA7010. J Mater Process Technol 66:179–185]. Iwata et al. performed research to investigate the relationship between shrinkage and pressure transfer time in the squeeze casting of Al-Si alloys [Iwata Y, Sugiyama Y, Iwahori H, Awano Y (2000) Transferred pressure and shrinkage cavity of aluminum alloys on squeeze castings. J Japan Foundry Eng Soc 72:263–267]. Basu et al. reported the mechanical properties of squeeze cast components revealing that the strength and ductility combination observed is better than that obtained in the case of permanent die casting [Basu K, Solonki RS, Muneshwar VS (1989) Squeeze casting of aluminum and its alloys. Indian Foundry October 25–34]. Wu et. al investigated the optimal set of parameters using Taguchi method for pressure die casting of Mg alloys components [Wu DH, Chang MS (2004) Use of Taguchi method to develop a robust design for the magnesium alloy die casting process. Mater Sci Eng A 379:366–371]. It is reported that squeeze cast LM25 component exhibits desirable structural properties and is superior to those produced in permanent moulds [13]. 

Though several research works applying Taguchi methods on die cast components have been reported in literature, it appears that very limited works have been carried out for squeeze cast components. On considering the importance of aluminum alloys, the main objective of the research was to apply Taguchi method to find the optimal set of control parameters for squeeze casting of LM24 aluminum alloy (Al 88%, Si 8%, Cu 3%, Fe 1%).

Source :

P. Vijian . V. P. Arunachalam : Optimization of squeeze casting process parameters using Taguchi analysis
Received: 7 March 2005 / Accepted: 10 January 2006 / Published online: 19 April 2006 from Springer-Verlag London Limited 2006