how a steam turbine casing is manufactured

2. BHARAT HEAVY
ELECTRICALS
LIMITED
Industrial Training
Presentation By:Omkar manav
10H51A0395
CMRCET COLLEGE

3. Flow of the presentation
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Over view
Vision, Mission & Values
Bhel products
Sector details
Financial Analysis
Bhel ramachandrapuram
Steam turbine classifications
Tc &gt producton activities
Machine shop
Machining of steam turbine casing

4. Overview of BHEL
 BHEL was established in 1964.
 BHEL is one of the only 7 Public Sector Undertakings (PSUs) of
India clubbed under the esteemed 'Maharatna' status. On 1st
February 2013, the Government of India granted Maharatna status
to BHEL.
 BHEL has a share of 59% in India’s total installed generating
capacity contributing 69% (approx.) to the total power generated
from utility sets (excluding non-conventional capacity) as of March
31, 2012.
 BHEL is engaged in the design, engineering, manufacture,
construction, testing, commissioning and servicing of a wide range of
products and services for the core sectors of the economy, viz.
Power, Transmission, Industry, Transportation (Railway), Renewable
Energy, Oil & Gas and defence.
 BHEL has 15 manufacturing divisions, two repair units, four regional
offices, eight service centers and 15 regional centers and currently
operate at more than 150 project sites across India and abroad.

6. Main Manufacturing Units
BHEL Bhopal (Madhya Pradesh )
BHEL Ramachandrapuram, Hyderabad (Andhra Pradesh)
Transformer Plant, BHEL Jhansi(Uttar Pradesh)
High Pressure Boiler Plant and Seamless Steel Tube Plant,
Tiruchirapalli(Tamil Nadu)
5. Boiler Auxiliaries Plant, Ranipet (Tamil Nadu)
6. ElectronicsDivision and Electro Porcelain Division,
Bangalore(Karnataka
7. Jagdishpur (Uttar Pradesh)
8. Rudrapur (Uttrakhand)
9. Industrial ValvesPlant, Goindwal (Punjab)
10. BHEL Ranipur, Haridwar (Uttarakhand)
11. Bharat Heavy Plates and Vessels Limited(Vizag)
1.
2.
3.
4.

7. 
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SERVICE GROUPS OF BHEL
Steam turbines, compressors and gas turbines
Common services
Heat exchangers and pulverizes
Pumps
Electrical machines
Quality services
Switch gears
Finance and accounts
Township administration
Project manager
Material management.

8. Product Range

9. Products
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Boiler(stream generator)
Gas Generator
Hydro Generator
Steam turbine
Gas turbine
Hydro turbine
Transportation Equipments
Traction Machines
Transformer
Switchgear
Oil field equipments OFE
Boiler drum
Water wall panel
Wind mill
Valve
Electro-static Precipitator
sR & D products

10. Generator:
 Operating Principle: The rotor is
mounted on a shaft driven by
mechanical prime mover.
 A field winding (rotating ) carries
a DC current to produce a
constant magnetic field. An AC
voltage is induced in the 3phase stator winding (stationary)
to produce electrical Power.
 The electrical frequency of the
3-phase output depends upon
the mechanical speed and the
number of poles.
 3-phases output is directly
connected to load.

11. Steam Turbine
 A steam turbine is a
device that
extracts thermal
energy from
pressurized steam and
uses it to do mechanical
work on a rotating output
shaft.
 The steam turbine is a
form of heat engine that
derives much of its
improvement in
thermodynamic
efficiency from the use of
multiple stages in the
expansion of the steam,
which results in a closer
approach to the ideal
reversible expansion

12. Pulverizer
 The coal is put in the boiler after pulverization. For
this pulverizer is used.
 A pulverizer is a device for grinding coal for
combustion in a furnace in a power plant.
 Types of Pulverizers:
i)Ball and Tube Mill
ii) Ring and Ball

13. Boiler
 Boiler is an enclosed vessel in
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2.
3.
4.
which water is heated and
circulated until the water is turned
in to steam at the required
pressure.
Coal is burned inside the
combustion chamber of boiler.
The products of combustion are
nothing but gases. These gases
which are at high temperature
vaporize the water inside the
boiler to steam.
Boilers are classified as:
Fire tube boilers
Water tube boilers
Superheater
Reheater

14. Condenser
 Steam after rotating steam turbine comes to condenser.
Condenser refers here to the shell and tube heat
exchanger (or surface condenser) installed at the outlet
of every steam turbine in Thermal power stations of utility
companies.
 The purpose is to condense the outlet (or exhaust) steam
from steam turbine to obtain maximum efficiency and
also to get the condensed steam in the form of pure
water, otherwise known as condensate, back to steam
generator or (boiler) as boiler feed water.
 Condensers are classified as:
i)Jet condensers or contact condensers,
ii)Surface condensers.

15. Cooling Towers
 The condensate (water)
formed in the condenser after
condensation is initially at
high temperature. This hot
water is passed to cooling
towers.
 It is a tower- or building-like
device in which atmospheric
air (the heat receiver)
circulates in direct or indirect
contact with warmer water
(the heat source) and the
water is thereby cooled.
 Types Of Cooling Tower1. Wet cooling tower
2. Dry cooling tower

16. Economizer
 Flue gases coming out of the
boiler carry lot of heat. Function
of economizer is to recover
some of the heat from the heat
carried away in the flue gases
up the chimney and utilize for
heating the feed water to the
boiler.
 It is placed in the passage of
flue gases in between the exit
from the boiler and the entry to
the chimney.
 The use of economizer results
in saving in coal consumption,
increase in steaming rate and
high boiler efficiency but needs
extra investment and increase
in maintenance costs and floor
area required for the plant.

17. Electrostatic Precipitator
 It is a device which removes dust or
other finely divided particles from flue
gases by charging the particles
inductively with an electric field, then
attracting them to highly charged
collector plates.
 Some of the usual applications are:
 (1) Removal of dirt from flue gases in
steam plants
 (2) Cleaning of air to remove fungi and
bacteria in
establishments producing
antibiotics and
other drugs, and in
operating rooms
 (3) Cleaning of air in ventilation and air
conditioning systems
 (4) Removal of oil mists in machine
shops and acid mists in chemical
process plants
 (5) Cleaning of blast furnace gases
 (6) Recovery of valuable materials such

18. Alternator
 An alternator is an electromechanical device that
converts mechanical energy to alternating current
electrical energy. Most alternators use a rotating
magnetic field. Different geometries - such as a
linear alternator for use with sterling engines - are
also occasionally used. In principle, any AC
generator can be called an alternator, but usually the
word refers to small rotating machines driven by
automotive and other internal combustion engines.

19. Transformers
 It is a device that transfers electric
energy from one alternating-current
circuit to one or more other circuits,
either increasing (stepping up) or
reducing (stepping down) the voltage.
 Uses for transformers include reducing
the line voltage to operate low-voltage
devices (doorbells or toy electric
trains) and raising the voltage from
electric generators so that electric
power can be transmitted over long
distances.
 Transformers act through
electromagnetic induction; current in
the primary coil induces current in the
secondary coil. The secondary voltage
is calculated by multiplying the primary
voltage by the ratio of the number of
turns in the secondary coil to that in
the primary.

20. Sector Details
 Power transmission sector, high voltage direct current (HVDC)
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technology. It manufactures a vast range of transformers,
instrument transformers, thyristor valves, and associated control
equipment.
Industrial equipment sector, BHEL supplies a wide variety of
electrical, electronic and mechanical equipment to a host of
industries, viz. fertilizers, petrochemicals, refineries, coal, steel
etc.
Oil and Gas, BHEL has designed, manufactured and serviced
various types of on-shore deep drilling rigs, super-deep drilling
rigs, mobile rigs and desert rigs with matching draw works and
hoisting equipment
Telecommunication area BHEL has manufactured electronic
private automatic branch exchanges (PABXs) and rural
automatic exchanges (RAXs) for India
Non-conventional energy, BHEL has contributed by way of
manufacturing equipment like solar water heating systems, solar
photo-voltaic systems and wind electric generators

21.  Transportation sector, over 66% of the Indian Railways, is
equipped with traction equipment by BHEL. Kolkata Metro is
equipped with BHEL drives and controls.
Other products in the sector include traction generators/
alternators, transformers, sub-station equipment, vacuum circuit
breakers, locomotive bogies, smoothing tractors, exciters,
converters, inverters,

22.  Technological Strategy
 Research and Development Strategy
 Work-Culture and Philosophy
 Vendor Development
 Quality Strategy
 Manufacturing Strategy
 Flexible Manufacturing Technology
 Share Point Portal Server
 Other strategies

24. BHEL:
Financials

26. BHEL Ramachandrapuram
Unit
 BHEL Ramachandrapuram Unit has acquired considerable experience in the
design and manufacture of various important types of pumps required for the
thermal power plants
 designed and manufactured for 60 MW, 110 MW and 210 MW under
technical collaboration with M/s. Sigma Lutin of Czechoslovakia.
 In order to meet the requirements of higher efficiency pumps for 210 MW
units and large capacity pumps for 500 MW units, collaboration was entered
in 1980 with M/s. Wier Pumps Limited, U.K., who are acknowledged as one
of the leading manufacturers of pumps in the world.
 In 2007, BHEL Hyderabad has entered into collaboration with M/s. Mitsubishi
Heavy Industries, Japan to manufacture pumps for super-critical thermal
power plants up to 1000 MW

28. 
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PRODUCT AND PROCESSES
Turbine & Compressors shop.
Steam Turbines Compressors.
Gas Turbines Compressors.
Turbo Generators.
Steam Generators.
Gas Generators.
Switch Gears.
Ferrous Foundry.
Non-Ferrous Foundry.
Heat Exchangers.
Tool Room.
Heat Treatment.
Pattern shop.
Spares Manufacturing.
Coal pulverizes.
Pumps.

29. Steam turbines
manufactured
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 STEAM TURBINES MANUFACTURED IN BHEL –HYD
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 Various types of SIEMENS model turbines are manufactured at BHEL – Hyderabad
according to the requirement of any customer to suit his boiler steam parameters.
 They are:
 Type Turbine
 G - Back pressure type
 EG - Extraction back pressure type
 EHG - Extraction back pressure type with high inlet parameters
 HG - Back pressure type with high inlet parameters
 K - Condensing type
 EK - Extraction condensing type
 WK - Double flow condensing type
 EMG - Electrochemically machined rotor of back pressure type
 EHNK - Extraction condensing with inlet parameters and high speed type
 NK - Straight condensing with high speed type
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30. Catogaries in steam turbine
 Industrial steam turbine are categorized into different
series like
 -2 series
 -3 series
 -4 series

31. 2 SERIES
TURBINES
 standard type and have been
designed for the best efficiency
for range parameters.
 Designs being the standard
further based on then steam flow
quantities size of the turbine is
selected
 in these series of turbines the
fixed blade grooves are
machined directly in the outer
casing and guide blades are
inserted

32.  Different sizes of -2 types of turbines are:
 G250-2 EK/K 600-2
 G300-2 EK/K 800-2
 G400-2 EK/K 1000-2
 G500-2 EK/K 1100-2
 G800-2 EK/K 1400-2
 “G” stands for back pressure turbine
 “K” stands for condensing turbines
 “E” stands for controlled extraction

33. -3 SERIES
TURBINE:
 Based on customer‟s requirements
and steps involved in design, the
turbine is divided into different
sections: inlet section, transition,
exhaust or condensing section
 the size of the section is geometrically
graded in the ratio to 1.25 to form
different sizes of section

34. TURBINES
:
 These types of series are called as
centre admission steam turbines with
counter flow
 range of power, between 30MW to 150
MW
 The steam reverses the direction on the
reaching the end of inner casing to flow
around inner casing and expands
towards the rear end of the turbine
 This process of reverse flow of steam
helps in control the axial thrust to a large
extent.
 These turbines are directly coupled to
the generator. The valve blocks in these
turbines are separate

35. TC&GT PRODUCTION
ACTIVITIES

36. Machine shops
 Bay 0
 Maintenance and service dept /
Heavy duty CNC machines / Steam
turbine 150 MW Assembly shop
 Bay 1
 Heavy duty CNC machines / Gas
turbine rotor Assembly
 Bay 2
 Heavy machine shop withHeavy
duty CNC and conventional
machines
 Bay 3
 Blade shop
 Bay 4
 Heavy duty CNC Lathe machines
and steam turbine rotor assembly
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Bay 5
 Impeller shop / Light machine shop / Gas
turbine wheel Assembly
Bay 6
Medium machine shop
 Bay 7
 Gas turbine machine shop / Steam turbine
Regulation Assembly

37. QiQihar CNC horizontal boring machines 2 nos
Tacchi CNC lathes 2 nos

38. QiQihar CNC horizontal boring
machines 2 nos

39. Tacchi CNC lathes 2 nos

40. INNSE Horizontal CNC machine :
Mario Carnaghi Gantry type machine :
Gas turbine Rotor Balancing machine
Tacchi heavy duty CNC lathe:

41. machine :
Short cut t o inse23.lnk

42.  This machine is provided with Sinumerik
840C CNC system

43. Mario Carnaghi Gantry type
machine :
 Rough machining of heavy
 Rough machining of heavy
casings of 120 MW design is
carried out on this machine.
Both top and bottom casings
 can be placed side by side on
the table with the parting plane
up for machining.
casings of 120 MW design is
carried out on this machine.
Both top and bottom casings
 can be placed side by side on
the table with the parting plane
up for machining.


44. Gas turbine Rotor Balancing machine
:
 The rotors are balanced
individually and as a unit rotor
also for its unbalance before
lowering into the gas Gas
turbine Rotor Balancing
machine :
 Machining of heavy rotors,
drilling, reaming of Coupling
holes on turbine rotor and load
coupling of gas turbine also
carried out in this shop

46. Tacchi heavy duty CNC lathe:

47. Tacchi heavy duty CNC lathe:
 Machining of heavy duty rotors
are carried out on this machine.
The max weight carrying
capacity of the machine is 80 T.
This machine is provided with
Sinumerik 840 D CNC system.
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 Gas turbines of Fr5, Fr6 and
Fr9 flange to flange assembly
is carried out here.

48. Bay 2
Heavy machine shop withHeavy duty CNC
and conventional machines
 withHeavy duty CNC and
conventional machinesHeavy
machine shop
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 Machining of peripheral
details and grinding of
parting planes of
casings are carried put
in this shop. The
important machines in
this bay are Plano
grinding machine etc
Radial drilling machines
etc
 Heavy duty CNC machines:
 Mitsubishi Horizontal boring
machine :
 DorriesVeritical CNC lathe:
 Skoda Horizontal boring machine:
 Skoda Vertical CNC lathe:

49. Mitsubishi Horizontal boring machine
:
 Fir tree blade root machining
on steam turbine rotor is
carried out on this machine
 Fanuc 9 CNC system.

50. Skoda Horizontal boring
machine
 Machining of combustion bores
on gas turbine casings,
peripheral details on steam
turbine casings are carried out
on this machine

51. Skoda Vertical CNC lathe:
 Finishing machining casings
including guide blade grooves
are carried out in vertical
position on this lathe. The
machine is provided with 840-C
CNC system.

52. Bay 4
Heavy duty CNC Lathe machines and steam
turbine rotor assembly
 Heavy duty CNC Lathe machines and
steam turbine rotor assembly
 Functions of bay
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Steam Turbine rotor Assembly :
Sealing fins drawing machine
LP drilling Machine :
A-Wheel drilling Machine (Impulse blade
drilling machine

53. CASING SHELL OR
CYLINDER

54. Casing Materials
 ASTM A 356 Grade 1
for cast carbon steel
 Nodular Cast Iron
GGG40
 The reason is that cast
carbon steel is weld
repairable(LP turbine
inner casing rings,)

55.  Properties
 1-2 cr mo steels –low
 applications as they
temperature steam
 Cast 9 Cr 1 –Mo- V –Nb
alloys
 9-12-cr martensite
/ferrite steel
offer useful
 combination of high
temperature mechanical
 properties and
corrosion/oxidation
resistance

56. Casing bolts
Bolting material
properties
Nimonic 80A
Inconel 740
Allvac 718 plus (super alloy )
 High resistance to stress
relaxation
 Creep relaxation behaviour
 offering excellent
mechanical properties,
 increased temperature
capability, good fabricability
and moderate cost

57.  Unstable states arising during
start-ups, shutdowns and load
changes give rise to unsteady
temperature distribution with time
in steam turbine innercasing
(HP/IP), which results in nonuniform strain and stress
distribution
The rapid increase of temperature
during starts-ups, especially,
causes susceptible to failure and
reduction of expected life for steam
turbine components. Thus accurate
knowledge of thermal stresses is
required for the integrity and
lifetime assessment for the turbine

58.  MACHINING
SEQUENCE
UNDERGONE BY STEAM
TURBINE
-3 CASING:

59. Casing

60.  Lower half
 Upper half

61.  1)Marking on both lower half and upper half
of casing with machine allowance
 Or
 Punching on cnc machine during machining
with allowances
 2)Skin cut on connecting flang face of lower
half by positioning the parting plane
downwards this process is repeated for
upper half also
 (INNSE MACHINE )
 3)Now the loading the lower half in vertical
position by the help of bearing and clamps
 4)Repeat the process for upper half as well
 5)Parting plane present in both upper half and
lower half are rough milled and then are
followed by finish milling by positioning the
job in vertically with inner part facing the
milling cutter (INNSE)

62.  Parting plane in lower and upper half are
drilled and threaded as per the drawing
provided
 While providing reses the job is still in
vertical position
 Eccentric pin holes packets machining
followed by pin holes drilling and finish
boring is operation is done only in lower half
 10)Drain holes drilling and slots milling done
only in lower half
 11)Guide blade carriers shoulders
machining only in lower half
 12)Guide blade carriers guides are done
rough milling
 13)Steam chest area machining is done
only in upper half
 14)Job position is changed and clamped in
vertical positonie the casing is placed
backside towards the spindle of machine

63.  Now the casing is moved to next machine for
further operation
 ( TOS KURIM)
 Parting plane holes done backcounter boring in
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both lower and upper half
Eccentric pin holes are back counter bored and
holes are positioned this is done only in lower
half
18)Steam valve spindle boring drilling and finish
boring is done only in upper half
19)Resting paws are milled in upper half
20)Job position is changed and loaded as
combined part on an hydraulic box and
tightened with studs and capnut for stiffness

64.  21)combined position is loaded on machine
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table
22)Job in combined position is performed with
finish boring of guide blade carriers and
connecting flange
23)Connecting flange holes are drilled and
provided with threading
24)Now the combined part is rotated by 180
25)Front gland is rough milled
26)The combined job is sent for inspection
27)After inspecting the job is dismantled
28)Now the job is loaded in vertical position
with parting plane facing the spindle of machine
29)Rough and finish machining of balance
piston gland is done by vertical attachment
30)Job is inspected
31)Stop valve body finish boaring in upper half
32)Diffuser bore finishing bores finish boring
and inspection

65. Machining for peripheral holes
 a)Peripherial holes radial drilling
both inside and outside of casing
 h)Focing off screw holes
 b)Flange fixing holes
 34)Blue matching both the halves
 c)Wall temperature measurement
holes
to ensure parting plane contact
area by 90% to 100%
 35)If not performing a) scraping
b)deburing
 36)Hydraulic pressure testing
 37) sent for assembly
 d)Thermoelement holes
 e)Pressure test holes (hydraulic
pressure tasting holes)
 f)Tapper pin holes
 g)Guide pinning holes
 i)Main steam inlet flange holes