Centrifugal casting machine must have the
provision for the given dimensions of the turbine
bearing.
(1) length of bearing= 700mm
(2) diameter of bearing=1200mm
(3) Weight of the bearing = 3tonne
(4) Required output speed during pouring of
molten metal = 10 rpm
(5) Required output speed after pouring =300 rpm
(6) Thickness of the job = 100mm
III. HOW THIS PROJECT BENEFICIAL TO
INDUSTRY?
Manufacturing point of view, the equipment
cost is economical and its design is similar as center
lathe machine. By this point, this project will
beneficial to industry.
IV. SCOPE OF THE WORK
The scope of work concerns to the development of
a centrifugal casting equipment to produce steam
turbine bearing with gradient of properties. Steam
turbine bearing which is a thrust bearing require
different properties in different areas of their body,
such as high thermal fatigue resistance in the top,
high wear resistance in the vane and low weight in
the body. Reliable processing techniques for that
purpose have not been established yet, and results
obtained so far reveal sharp and undesirable
interfaces. A possible solution might be a well
controlled sequential pouring technique of different
materials that lead to a smooth gradient of
composition/properties between different turbine
bearing's functional areas, using centrifugal casting.
For this special purpose, a design of a horizontal axis
centrifugal casting machine will be developed. A
sketch of the equipment is developed and established
the main components. Finally, the design and
selection of the system‘s components will be done
accordingly to the main goals of this work.
IV. MACHINE COMPONENTS
The general idea of designing this special
purpose machine came from the headstock and
tailstock assembly of the centre lathe machine. The
job is supported between the faceplate of the
machine during pouring and rotating of the mould.
The job is not long in length so roller support is not
required as required to conventional horizontal
centrifugal casting for long cylindrical job. The
machine is same as lathe with separate tailstock and
headstock assembly. The list of various component
that will be used in this special purpose machine as
follows:
(1) Headstock assembly
1) A 3-phase induction motor
(30 hp with input speed=1440 rpm)
2) Helical gearbox
3) Hollow Shaft
4) Taper Roller Bearing
5) Faceplate
(2) Tailstock assembly
1) Faceplate
2) Taper Roller Bearing
3) Hollow Shaft
4) Molding Flask and its attachment
(3) Rotating Mould
(4) Guideways
(5) Leadscrew
(4) Variable Freqency Drive
V. PROCESS CYCLE FOR MANUFACTRING
OF TURBINE BEARING
The casting process is usually performed on a
horizontal centrifugal casting machine (vertical
machines are also available) and includes the
following cycle as shown in figure 2