2. MANUFACTURING OF STEAM
TURBINE
Presented by: Sushil kumar
Roll no.-110106281
Sharda University
3. INTRODUCTION:
BHEL is the largest engineering and manufacturing enterprise in
India in the energy related infrastructure sector today.
BHEL was established more than 40 years ago when its first plant
was setup in Bhopal.
BHEL is one of India’s nine larger Public Sector Undertakings or
PSUs ,known as the NAVRATNAS or the nine jewels .
The wide network of BHEL's 14 manufacturing division, four
power Sector regional centre, over 150 project sites, eight service
centre and 18 regional offices.
BHEL has already attained ISO 9000 certification for quality
management, and ISO 14001 certification for environment
management
4. The power plant equipment manufactured by BHEL is based on
contemporary technology comparable to the best in the world and is
also internationally competitive.
BHEL is the only company in India with the capability to make
simultaneous for power plants, defense and other applications.
Supplied traction electrics and AC/DC locos to power over
12000kms railway network.
Supplied over one million valves to power plants and other
industries.
7. STEAM TURBINE:
Turbine is an engine that converts energy of fluid into mechanical
energy .
Steam turbine depends completely upon the dynamic action of the
steam.
Steam turbine is steam driven rotary engine.
8. TYPE OF STEAM TURBINE
Impulse turbine
Reaction turbine
9. IMPULSE TURBINE
The basic idea of an impulse turbine is that a jet of
steam from a fixed nozzle pushes against the rotor
blades and impels them forward.
The velocity of steam is twice as fast as the velocity
of blade.
Pressure drops take place in the fixed blade
(nozzle).
10. SINGLE STAGE IMPULSE TURBINE
The turbine consists of a single rotor to which
impulse blades are attached.
The steam is fed through one or several
convergent nozzles.If high velocity of steam is
allowed to flow through one row of moving
blades.
It produces a rotor speed of about 30000 rpm
which is too high for practical use.
11. REACTION TURBINE
A reaction turbine utilizes a jet of steam that
flows from a nozzle on the rotor.
Actually, the steam is directed into the moving
blades by fixed blades designed to expand the
steam.
The result is a small increase in velocity over
that of the moving blades.
13. PROBLEM IN STEAM TURBINE
Stress corrosion
Corrosion fatigue
Pitting
Oil lubrication
imbalance of the rotor can lead to vibration
misalignment
Thermal fatigue
15. WORKING OF STEAM TURBINE:
Impulse Turbine:-
• steam is expanded only in nozzles.
• Blade passage of constant cross-section
area.
Reaction Turbine:-
• Pressure drop in fixed & moving blade.
• Blade passage of varying cross-section
area.
16. ROTOR AND CASING OF STEAM
TURBINE:
HP (High Pressure)
IP (Intermediate Pressure)
LP (Low Pressure)
17.
18. Manufactured blade according to specifications with the
help of CNC 3AXIS MACHINE.
In order to meet the increasing demand to manufacture complicated
components of high accuracy in large quantities, sophisticated technological
equipment and machinery have been developed.
•The design and construction of Computer Numerically Controlled (CNC)
machines differs greatly from that of conventional machine tools. This
difference arises from the requirements of higher performance levels.
•The control of a machine tool by means of stored information through the
computer is known as Computer Numerically Controlled. The information
stored in the computer can be read by automatic means and converted into
electrical signals, which operate the electrically controlled servo systems.
•Computer Numerically Control can be applied to milling machines ,Lathe
machines, Grinding machines, Boring machines, Flame cutters, Drilling
machines
19. BLADE MANUFACTURING
Operations Performed On Blades:
Inspection
Cutting
Milling
Grinding on both the surface
Machining Of Blades:
Horizontal milling machine
Central lathe machine
CNC machine
Vertical boring machine
20. MANUFACTURING OF BLADE
PROCESS
The different processes followed in the
manufacture of steam turbine blade on cnc 3axis
machine as follows
1. RAW MATERIAL PROCUREMENT:
The steam turbine blade material is procured as
per the design specification. The material is
inspected dimensionally
21. CONT.
2.LENGTH CUTTING:
The material is cut to length by keeping
machining allowance at both ends either by Band
Saw or by Power Hack Saw.
3. THICKNESS MILLING
The material is clamped in a vice or fixture and
thickness is milled on both sides by keeping n
allowance of 0.5mm on both sides for grinding.
This operation is done either by horizontal
milling machining or by vertical milling machine.
22. CONT.
4.THICKNESS GRINDING:
The milled bars are debarred and kept on a
magnetic chuck of the segmental surface
grinding machine. 5 to 10 blades are kept each
time depending on the size and ground each side
to maintain the dimension.
5. RHOMBOID MILLING:
The ground blade bars are milled to rhomboid
shape with an angle given in the process by
clamping in a fixture on both sides with an
allowance of 0.5mm on both side. This is done on
the horizontal milling machines.
23. CONT.
6. RHOMBOID GRINDING:
The milled bars are debarred and kept on
magnetic chuck of the surface grinder and
grinding is done on both sides.
7. FACING AND SIZE MILLING:
The ground blades are faced on the root side to
maintain perpendicularity. This is very
important as the blade is held on this face while
in assembly.
24. CONT.
ROOT MILLING:
Clamp the blade in a vice or fixture and machine
the root on both sides as per drawing keeping an
allowance for root radius. Do not machine 2 blade
as these are used for locking purpose. This
operation is done on horizontal milling machine.
9. ROOT RADIUS MILLING:
Clamp the blade in a vice or fixture and machine
the root radius as per drawing by CNC M aching
centre. This operation is done on CNC Vertical
machining centre by CNC Program.
25. CONT.
10. WIDTH MILLING:
The profile width is done on both sides on
horizontal milling machine as per the drawing.
11. CONVEX MILLING:
The milling is done on convex side by aCNC
machining center. The CNC Program is
developed based on the profile coordinates and
then loaded into the CNC system of the machine.
26. CONT.
12. CONCAVE MILLING:
The profile milling is done on concave side by a
CNC machining center. The CNC Program is
developed based on the profile coordinate and
then loaded in to the CNC system of the
machine.
13. TAPER MILLING:
The taper milling is done on a horizontal milling
machine by putting in a fixture specially made.
The taper is calculated from sine values and
machined accordingly.
27. CONT.
14. TAPER GRINDING:
The taper grinding is done on a surface grinding
machine and ensure the angle with in the given
tolerance in the diagram. Also surface finish
must be with in 8 microns.
15. FITTING AND POLISHING:
The blades are debarred and rounded off on the
inlet side and then polished on blade polishing
machine.
28. CONCLUSION ON BLADE
MANUFACTURING
As we understood that the efficiency and
reliability of a steam turbine depends on the
proper design of blades.
•The reliability of moving blades is to be ensured
upon proper design selection of material.
•In blade profile where as in impulse the entire
heats drop occurs in stationary blades.
•The fork root has higher load carrying capacity
than T‐root.
•Different milling cutters are used to finish the
operation on the blade.
•The growth for the steam turbines are very high
and demand for blades is growing.
29. Mostly 500MW turbine blades are manufactured in this shop.
Basically the design of blades is classified according to the stages of
turbine.
The size of LP Turbine blades is generally greater than of HP
Turbine blades.
30. OVER SPEED BALANCING
TUNNEL:
Features:
max. thickness of tunnel : 2500mm
tunnel diameter : 9000mm
min. vibration limit : 1micron
over speed limit : 2500 to 4500 rpm
rotor balancing of max. : 600Mw
rating
type of pedestal : DH 90/ DH 12
31. CONCLUSION:-
BHEL is the largest engineering and manufacturing enterprise in
India .
The company manufactures 235 MW nuclear turbine generator sets
and in future it will 500 MW.
BHEL is a major contributor of equipment and systems to
industries.
At the all, till now BHEL is best in supply and manufacturing
products.
