compound casting - a literature review - YMCA University of Science ...

Proceedings of the National Conference onTrends and Advances in Mechanical Engineering,YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012researchers have used compound casting to join different similar and dissimilar metallic couples such assteel/cast iron, steel/Cu, steel/Al, Cu/Al, Al/Al, and Mg/Mg, joining dissimilar light metals such as aluminumand magnesium by the compound casting process is still a relatively unexplored area. In this study, compoundcasting as an economic straightforward in situ technique was used to join dissimilar aluminum and magnesiumlight metals.Through the combination of various materials, this compound casting process can help components meet themost diverse of requirements. And with the hybrid construction process, the material bond is created by recasting– separate hot or cold bonding/jointing processes are not necessary. This in turn reduces the number ofproduction steps needed in the manufacturing process.A good example of applications in this field is the manufacturing of engine blocks. As a pure sheet steel solution,it consists of numerous individual parts which are joined to one another. In contrast, the compound castingsolution makes it possible to produce this component as a single piece. The intelligently designed casting madefrom aluminium or magnesium alloy ensures the high functional integrity of flanges and bearing carriers, forinstance.In difficult areas, a carefully positioned insert such as a semi-finished product made of steel or an aluminumalloy provides the necessary strength. In comparison with conventional die casting, the manufacture of acompound casting piece requires additional handling, for example manipulation of inserts or perhapspretreatment of the surfaces.3.1. Applications of Compound CastingCompound casting parts are already used in vehicle construction for parts of the chassis, such as the engineblock, shock strut supports and gearbox casing, as well as bodywork components, for example door frames andconnection supports and as dashboard mounts in the interior. And according to information from the automotiveindustry, multi-material components are on the increase. This is proven by compound cast parts such as the 6-cylinder magnesium engine with aluminum insert from BMW and other components which are undergoingdevelopment but have not yet been announced. The aircraft industry, too, is relying more and more on compoundcast materials.3.2. Compound Casting ProcessThe compound casting process to prepare the Al/Mg couples from commercially pure aluminum andcommercially pure magnesium are as under.In this process cylindrical inserts with 20 mm diameter and 100 mm height were machined from aluminum andmagnesium ingots. Their surfaces were ground with silicon carbide papers up to 1200 grit, then rinsed withacetone and placed within a cylindrical cavity of a CO2 sand mold with 30 mm diameter and 80 mm height. Twoseries of samples were prepared. In the first series, aluminum ingots were melted in a clay-graphite crucibleplaced in an electrical resistance furnace. The molten aluminum was cast around the magnesium inserts at 700 0 Cunder normal atmospheric conditions.In the second series, magnesium ingots were melted in a steel crucible placed in the same furnace under thecovering flux, to protect magnesium melt form oxidation. The molten magnesium was cast around the aluminuminserts at 7000 C under normal atmospheric conditions. Schematic sketches of the mold used in the castingprocess and the prepared Al/Mg couple are illustrated in Fig. 1.Figure 1 Schematic sketches of (a) the mold used for the casting process and (b) the prepared Al/Mg couple.502