Abstract:
The study investigates the application of centrifugal casting process in the production of
a complex shape component, Pelton turbine bucket. The bucket materials examined were
functionally graded aluminium A356 alloy and A356-10%SiCp composite. A permanent mould for
the casting of the bucket was designed with a Solidworks software and fabricated by the
combination of CNC machining and welding. Oil hardening non-shrinking die steel (OHNS) was
chosen for the mould material. The OHNS was heat treated and a hardness of 432 BHN was
obtained. The mould was put into use, the buckets of A356 Alloy and A356-10%SiCp composite
were cast, cut and machined into specimens. Some of the specimens were given T6 heat treatment
and the specimens were prepared according to the designed investigations. The micrographs of
A356-10%SiCp composite shows more concentration of SiCp particles at the inner periphery of the
bucket. The maximum hardness of As-Cast A356 and A356-10%SiCp composite were 60 BRN and
95BRN respectively, recorded at the inner periphery of the bucket. And these values appreciated to
98BRN and 122BRN for A356 alloy and A356-10%SiCp composite respectively after heat
treatment. The prediction curves of the ultimate tensile stress and yield tensile stress show the same
trend as the hardness curves.
