OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
researchers have used compound casting to join different similar and dissimilar metallic couples such as
steel/cast iron, steel/Cu, steel/Al, Cu/Al, Al/Al, and Mg/Mg, joining dissimilar light metals such as aluminum
and magnesium by the compound casting process is still a relatively unexplored area. In this study, compound
casting as an economic straightforward in situ technique was used to join dissimilar aluminum and magnesium
light metals.
Through the combination of various materials, this compound casting process can help components meet the
most 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 of
production 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 casting
solution makes it possible to produce this component as a single piece. The intelligently designed casting made
from aluminium or magnesium alloy ensures the high functional integrity of flanges and bearing carriers, for
instance.
In difficult areas, a carefully positioned insert such as a semi-finished product made of steel or an aluminum
alloy provides the necessary strength. In comparison with conventional die casting, the manufacture of a
compound casting piece requires additional handling, for example manipulation of inserts or perhaps
pretreatment of the surfaces.
3.1. Applications of Compound Casting
Compound casting parts are already used in vehicle construction for parts of the chassis, such as the engine
block, shock strut supports and gearbox casing, as well as bodywork components, for example door frames and
connection supports and as dashboard mounts in the interior. And according to information from the automotive
industry, 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 undergoing
development but have not yet been announced. The aircraft industry, too, is relying more and more on compound
cast materials.
3.2. Compound Casting Process
The compound casting process to prepare the Al/Mg couples from commercially pure aluminum and
commercially pure magnesium are as under.
In this process cylindrical inserts with 20 mm diameter and 100 mm height were machined from aluminum and
magnesium ingots. Their surfaces were ground with silicon carbide papers up to 1200 grit, then rinsed with
acetone and placed within a cylindrical cavity of a CO2 sand mold with 30 mm diameter and 80 mm height. Two
series of samples were prepared. In the first series, aluminum ingots were melted in a clay-graphite crucible
placed in an electrical resistance furnace. The molten aluminum was cast around the magnesium inserts at 700 0 C
under normal atmospheric conditions.
In the second series, magnesium ingots were melted in a steel crucible placed in the same furnace under the
covering flux, to protect magnesium melt form oxidation. The molten magnesium was cast around the aluminum
inserts at 700
0 C under normal atmospheric conditions. Schematic sketches of the mold used in the casting
process 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