DECLARATION

I, …………….., B Tech (3rd year) of ……….. college here by declare that the

training Report entitled “Heavy Fabrication Block”, is an original work and the

same has not been submitted to any other Institute.

Presentation In-charge Signature of the candidate

(Faculty)

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ACKNOWLEDGEMENT

It gives me immense pleasure to present my Project Report before you. I

thankfully acknowledge the staff of BHEL, Haridwar for giving me so much

co-operation and taught lots of new things to me, which I am sure will help me

in my war future.

A special thanks to Mr. ……… for his support during my Industrial

Training. I pay my sincere regards to him. Without his support I was not able to

accomplish my training. I also thanks to all the working staff of fabrication

block for their helpful guidance and support during the period.

I extend my thanks to my college for giving me such an opportunity

under the supervision of ……………….. (Training and Placement Officer)

who is also an experienced person.

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ABC

MECHANICAL (3rd YEAR)

UNIV. ROLL NO. -……….

COMPANY PROFILE

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BHARAT HEAVY ELECTRICALS LIMITED

BHEL – AN OVERVIEW

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 ushering in the indigenous

Heavy Electrical Equipment Industry in India a dream which has been more

than realized with a well recognized track record of performance it has been

earning profits continuously since 1971-72.

BHEL caters to core sectors of the Indian Economy viz., Power Generation's &

Transmission, Industry, Transportation, Telecommunication, Renewable Energy,

Defense, etc. The wide network of BHEL's 14 manufacturing division, four power

Sector regional centers, over 150 project sites, eight service centers and 18 regional

offices, enables the Company to promptly serve its customers and provide them

with suitable products, systems and services – efficiently and at competitive prices.

BHEL has already attained ISO 9000 certification for quality management, and ISO

14001 certification for environment managemen POWER GENERATION

Power generation sector comprises thermal, gas, hydro and nuclear

power plant business as of 31.03.2001, BHEL supplied sets account for nearly

64737 MW or 73% of the total installed capacity of 99,146 MW in the country,

as against nil till 1969-70.

BHEL has proven turnkey capabilities for executing power

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projects from concept to commissioning, it possesses the technology and

capability to produce thermal sets with super critical parameters up to 1000 MW

unit rating and gas turbine generator sets of up to 240 MW unit rating. Co-

generation and combined-cycle plants have been introduced to achieve higher

plant efficiencies to make efficient use of the high-ash-content coal available in

India, BHEL supplies circulating fluidized bed combustion boilers to both

thermal and combined cycle power plants.

The company manufactures 235 MW nuclear turbine generator sets and

has commenced production of 500 MW nuclear turbine generator sets. Custom

made hydro sets of Francis; Pelton and Kaplan types for different head

discharge combination are also engineering and manufactured by BHEL.

In all, orders for more than 700 utility sets of thermal, hydro, gas and

nuclear have been placed on the Company as on date. The power plant

equipment manufactured by BHEL is based on contemporary technology

comparable to the best in the world and is also internationally competitive.

The Company has proven expertise in Plant Performance Improvement

through renovation modernization and up rating of a variety of power plant

equipment besides specialized know how of residual life assessment, health

diagnostics and life extension of plants.

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POWER TRANSMISSION & DISTRIBUTION (T & D)

BHEL offer wide ranging products and systems for T & D applications.

Products manufactured include power transformers, instrument transformers,

dry type transformers, series – and stunt reactor, capacitor tanks, vacuum – and

SF circuit breakers gas insulated switch gears and insulators.

A strong engineering base enables the Company to undertake turnkey

delivery of electric substances up to 400 kV level series compensation systems

(for increasing power transfer capacity of transmission lines and improving

system stability and voltage regulation), shunt compensation systems (for power

factor and voltage improvement) and HVDC systems (for economic transfer of

bulk power). BHEL has indigenously developed the state-of-the-art controlled

shunt reactor (for reactive power management on long transmission lines).

Presently a 400 kV Facts (Flexible AC Transmission System) project under

execution.

INDUSTRIES

BHEL is a major contributor of equipment and systems to industries,

cement, sugar, fertilizer, refinances, petrochemicals, paper, oil and gas,

metallurgical and other process industries. The range of system & equipment

supplied includes: captive power plants, co-generation plants DG power plants,

industrial steam turbines, industrial boilers and auxiliaries. Water heat recovery

boilers, gas turbines, heat exchangers and pressure vessels, centrifugal

compressors, electrical machines, pumps, valves, seamless steel tubes,

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electrostatic precipitators, fabric filters, reactors, fluidized bed combustion

boilers, chemical recovery boilers and process controls.

The Company is a major producer of large-size thruster devices. It also

supplies digital distributed control systems for process industries, and control &

instrumentation systems for power plant and industrial applications. BHEL is

the only company in India with the capability to make simulators for power

plants, defense and other applications.

The Company has commenced manufacture of large desalination plants to

help augment the supply of drinking water to people.

TRANSPORTATION

BHEL is involved in the development design, engineering, marketing,

production, installation, and maintenance and after-sales service of Rolling

Stock and traction propulsion systems. In the area of rolling stock, BHEL

manufactures electric locomotives up to 5000 HP, diesel-electric locomotives

from 350 HP to 3100 HP, both for mainline and shunting duly applications.

BHEL is also producing rolling stock for special applications viz., overhead

equipment cars, Special well wagons, Rail-cum-road vehicle etc., Besides

traction propulsion systems for in-house use, BHEL manufactures traction

propulsion systems for other rolling stock producers of electric locomotives,

diesel-electric locomotives, electrical multiple units and metro cars. The electric

and diesel traction equipment on India Railways are largely powered by

electrical propulsion systems produced by BHEL. The company also undertakes

retooling and overhauling of rolling stock in the area of urban transportation

systems. BHEL is geared up to turnkey execution of electric trolley bus systems,

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light rail systems etc. BHEL is also diversifying in the area of port handing

equipment and pipelines transportation system.

TELECOMMUNICATION

BHEL also caters to Telecommunication sector by way of small, medium

and large switching systems.

RENEWABLE ENERGY

Technologies that can be offered by BHEL for exploiting non-

conventional and renewable sources of energy include: wind electric generators,

solar photovoltaic systems, solar lanterns and battery-powered road vehicles.

The Company has taken up R&D efforts for development of multi-junction

amorphous silicon solar cells and fuel based systems.

INTERNATIONAL OPERATIONS

BHEL has, over the years, established its references in around 60

countries of the world, ranging for the United States in the West to New Zealand

in the Far East. These references encompass almost the entire product range of

BHEL, covering turnkey power projects of thermal, hydro and gas-based types,

substation projects, rehabilitation projects, besides a wide variety of products,

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like transformers, insulators, switchgears, heat exchangers, castings and

forgings, valves, well-head equipment, centrifugal compressors, photo-voltaic

equipment etc. Apart from over 1110MW of boiler capacity contributed in

Malaysia, and execution of four prestigious power projects in Oman, Some of

the other major successes achieved by the Company have been in Australia,

Saudi Arabia, Libya, Greece, Cyprus, Malta, Egypt, Bangladesh, Azerbaijan, Sri

Lanka, Iraq etc.

The Company has been successful in meeting demanding customer's

requirements in terms of complexity of the works as well as technological,

quality and other requirements viz extended warrantees, associated O&M,

financing packages etc. BHEL has proved its capability to undertake projects on

fast-track basis. The company has been successful in meeting varying needs of

the industry, be it captive power plants, utility power generation or for the oil

sector requirements. Executing of Overseas projects has also provided BHEL

the experience of working with world renowned Consulting Organisations and

inspection Agencies.

In addition to demonstrated capability to undertake turnkey projects on

its own, BHEL possesses the requisite flexibility to interface and complement

with International companies for large projects by supplying complementary

equipment and meeting their production needs for intermediate as well as

finished products.

The success in the area of rehabilitation and life extension of power

projects has established BHEL as a comparable alternative to the original

equipment manufactures (OEMs) for such plants.

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TECHNOLOGY UPGRADATION AND RESEARCH &

DEVELOPMENT

To remain competitive and meet customers' expectations, BHEL lays

great emphasis on the continuous upgradation of products and related

technologies, and development of new products. The Company has upgraded its

products to contemporary levels through continuous in house efforts as well as

through acquisition of new technologies from leading engineering organizations

of the world.

The Corporate R&D Division at Hyderabad, spread over a 140 acre

complex, leads BHEL's research efforts in a number of areas of importance to

BHEL's product range. Research and product development centers at each of the

manufacturing divisions play a complementary role.

BHEL's Investment in R&D is amongst the largest in the corporate sector

in India. Products developed in-house during the last five years contributed

about 8.6% to the revenues in 2000-2001.

BHEL has introduced, in the recent past, several state-of-the-art products

developed in-house: low-NQx oil / gas burners, circulating fluidized bed

combustion boilers, high-efficiency Pelton hydro turbines, petroleum depot

automation systems, 36 kV gas-insulated sub-stations, etc. The Company has

also transferred a few technologies developed in-house to other Indian

companies for commercialization.

HUMAN RESOURCE DEVELOPMENT INSTITUTE

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The most prized asset of BHEL is its employees. The Human Resource

Development Institute and other HRD centers of the Company help in not only

keeping their skills updated and finely honed but also in adding new skills,

whenever required. Continuous training and retraining, positive, a positive work

culture and participative style of management have engendered development of

a committed and motivated work force leading to enhanced productivity and

higher levels of quality.

HEALTH, SAFETY AND ENVIRONMENT MANAGEMENT

BHEL, as an integral part of business performance and in its endeavour of

becoming a world-class organization and sharing the growing global concern on

issues related to Environment. Occupational Health and Safety, is committed to

protecting Environment in and around its own establishment, and to providing

safe and healthy working environment to all its employees.

For fulfilling these obligations, Corporate Policies have been formulated as:

ENVIRONMENTAL POLICY

Compliance with applicable Environmental Legislation/Regulation;

Continual Improvement in Environment Management Systems to protect our

natural environment and Control Pollution;

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Promotion of activities for conservation of resources by Environmental

Management;

Enhancement of Environmental awareness amongst employees, customers and

suppliers.

OCCUPATIONAL HEALTH AND SAFETY POLICY

Compliance with applicable Legislation and Regulations;

Setting objectives and targets to eliminate/control/minimize risks due to

Occupational and Safety Hazards;

Appropriate structured training of employees on Occupational Health and

Safety (OH&S) aspects;

Formulation and maintenance of OH&S Management programmes for continual

improvement;

Periodic review of OH&S Management System to ensure its continuing

suitability, adequacy and effectiveness;

HEEP: AN OVER VIEW

Over the years, Bharat Heavy Electricals Limited has emerged as world

class Engineering and Industrial giant, the best of its kind in entire South East

Asia. Its business profile cuts across various sectors of Engineering/Power

utilities and Industry. The Company today enjoys national and international

presence featuring in the "Fortune International-500" and is ranked among the

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top 12 companies in the world, manufacturing power generation equipment.

BHEL has now 14 Manufacturing Divisions, 8 Service Centres and 4 Power

Sectors Regional Centres besides a large number of project sites spread over

India and abroad.

The Company is embarking upon an ambitions growth path through clear

vision, mission and committed values to sustain and augment its image as a

world class enterprise.

VISION

World-class, innovative, competitive and profitable engineering

enterprise providing total business solutions.

MISSION

The leading Indian engineering enterprise providing quality products

systems and services in the fields of energy, transportation, infrastructure and

other potential areas.

VALUES

Meeting commitments made to external and internal customers.

Foster learning creativity and speed of response.

Respect for dignity and potential of individuals.

Loyality and pride in the company.

Team playing.

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Zeal to excel.

Integrity and fairness in all matters.

HEAVY ELECTRICAL EQUIPMENT PLANT (HEEP)

At Hardwar, against the picturesque background of Shivalik Hills, 2

important manufacturing units of BHEL are located viz. Heavy Electrical

Equipment Plant (HEEP) & Central Foundry Forge Plant (CFFP). The hum of

the construction machinery woke up Shivalik Hills during early 60s and sowed

the seeds of one of the greatest symbol of Indo Soviet Collaboration – Heavy

Electrical Equipment Plant of BHEL. Following is the brief profile of Heavy

Electrical Equipment Plant:-

1. ESTABLISHMENT AND DEVELOPMENT STAGES:

* Established in 1960s under the Indo-Soviet Agreements of 1959 and 1960 in the

area of Scientific, Technical and Industrial Cooperation.

* DPR – prepared in 1963-64, construction started from October '63.

* Initial production of Electric started from January, 1967.

* Major construction / erection / commissioning completed by 1971-72 as per

original DPR scope.

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* Stamping Unit added later during 1968 to 1972.

* Annual Manufacturing capacity for Thermal sets was expanded from 1500 MW

to 3500 MW under LSTG. Project during 1979-85 (Sets upto 500 MW,

extensible to 1000/1300 MW unit sizes with marginal addition in facilities with

the collaboration of M/s KWU-Siemens, Germany.

* Motor manufacturing technology updated with Siemens collaboration during

1984-87.

* Facilities being modernized continually through Replacements /

Reconditioning-Retrofitting, Technological / operational balancing.

2. INVESTMENTS:

* Gross Block as on 31.3.95 is Rs. 355.63 Crores (Plant and Machinery – Rs.

285.32 Crores).

* Net Block as on 31.3.95 is Rs. 113.81 Crores (Plant & Machinery – Rs. 76.21

Crores).

3. CLIMATIC AND GEOGRAPHICAL:

* Hardwar is in extreme weather zone of the Uttarakhand of India and

temperature varies from 2oC in winter (December to January) to 45oC in

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summer (April-June); Relative humidity 20% during dry season to 95-96%

during rainy season.

* Longitude 78o3' East, Latitude 29 o55'5" North.

* Height above Mean Sea Level = 275 metres.

* Situated within 60 to 100 KMs of Foot-hills of the Central Himalayan Ranges;

Ganges flows down within 7 KMs from the Factory area.

* HEEP is located around 7 KMs on the Western side of Hardwar city.

4. COMMUNICATION & TRANSPORTATION:

* Telegraphic Code – "BHARAT TELEC, HARDWAR"

* TLX Lines: 05909-206 / 207

* Telephones: P&T / STD – (01334) 427350-59, 423050-423954

FAX: (0091) (1334) 426462 / 425069 / 426082 / 426254

* Direct Board gauge train lines to Calcutta (Howrah), Delhi, Bombay, Lucknow,

Dehradun and other major cities; Railway Siding for goods traffic connected to

Hardwar Railway Station.

5. POWER & WATER SUPPLY SYSTEM:

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- 40 MVA sanctioned Electric Power connection from UP Grid (132 KV / 11KV /

6.6 KV) (Connected load – around 185 MVA)

- 26 deep submersible Tube Wells with O.H. Tanks for water supply.

- A 12 MW captive thermal power station is located in the factory premises.

6. FIRE PROTECTION:

- Managed by CISF with around 40 personnel and a host of latest fire fighting

equipment and fire tenders.

7. MANPOWER:

Total strength is 9904 as on 31.3.96 which includes around 3000 qualified

Engineers and Technicians (including substantial number of Post graduates),

5200 skilled artisans and the rest in other categories.

8. HEEP PRODUCT PROFILE:

* THERMAL AND NUCLEAR SETS

(Turbines, Generators, Condensers and Auxiliaries of unit capacity upto

1000 MW)

* HYDRO SETS INCLUDING SPHERICAL AND DISC

VALVES

(Kaplan, Francis, Pelton and reversible Turbines of all sizes and matching

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generators and auxiliaries’ maximum runner dia – 6600 mm)

* ELECTRICAL MACHINES:

(For various industrial applications, pump drives & power station auxiliaries,

Unit capacity upto 20000 KW AC / DC)

* CONTROL PANELS

For Thermal / Hydro sets and Industrial Drives

* LARGE SIZE GAS TURBINES

(Unit Rating: 60-200 MW)

9. HEEP: FACILITIES AND INFRASTRUCTURE

Modernisation and regular upgradation / up gradation of facilities and

other infrastructure is a continuous endeavour at HEEP, BHEL. After initial

setting up of the plant during the year 1964-72, in collaboration with the Soviet

Union, the plant facilities and infrastructures have since been continuously

upgraded under various investment projects viz, Stamping Unit Project, LSTG

Project, Motor Project, Governing Components Project, TG Facilities

Modernisation, TG Facilities Augmentation, Quality Facilities Augmentation,

EDP projects, Gas Turbine Project, Facilities have also been added and

establishments have been created for new projects in Defense and Aviation

Project. Additionally, R &D facilities have also been created under Generators

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Research Institute, Pollution Control Research Institute, HTL modernization and

other such schemes.

Today the Plant has unique manufacturing and testing facilities,

computerized numerically controlled machine-tools, Blade shop, heavy duty

lathes, milling machines, boring machines, machining centers and many more.

The Over Speed Vacuum Balancing Tunnel created for rotors upto 1300 MW

(32T, 6.9 M – dia bladed rotor, 6 rpm upto 4500 rpm) is one of the 8 of its kind

in the entire world.

The total spectrum of sophisticated, unique and other facilities at HEEP,

Hardwar are the state-of-the-art in manufacturing processes and can be utilized

for a variety of products' manufacture.

Heavy Fabrication Block

Details of facilities:

The fabrication block in block-2 which is the domain of our study is the feeder block for various products, steam turbine, hydro turbines, turbo generators, hydro generators, electrical machine, apparatus and control gears, gas turbine, and navel

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guns.

Block-2 consists of 4 bays, namely Bay no. I, II, III, IV of sizes 24*192, 36*192, 24*192 and 24*192 meters respectively and is provided with over head crane facility for movement of plates, gas cut blanks and finished products. This block has facilities for compressed air, oxygen, acetylene and carbon-di-oxide gas pipe lines.

Here, the brief description of manufacturing processes and facilities is given below:

Manufacturing facilities:

Preparation, Bay-I

It has following sections-

a) Marking, cutting and straightening section.

b) Gas cutting section including CNC flame cutting section and CNC Plasma section.

c) Press section (400T and 800t, brake press).

d) Shearing machine section.

The various machines that are used in different section in this Bay are followed:

Marking section:

First of all marking is done on the work piece according to the drawing given and then it is send to next section or machine for operation.

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Press section:

In this section mainly bending operation is done. The machine used and their introduction is given below:

1. CNC brake press machine (340 EHP)

This is a CNC machine. In which data is given to machine by the operator according to the drawing and after then the bending operation is done automatically by the machine through hydraulic pressure.

Description:

Material handled: usually all metal

Job handled: bending of 2mm to 25mm thick plate at any angle

EHP (estimated horse power): 340

2. 800EHP hydraulic press machine

This is a manual control machine. In this machine hydraulic pressure is used for bending operation.

Description:

Material handled: usually S.S. and M.S.

Job handled: bending and straightening of plate up to 130mm thick at angle according to the job requirement.

EHP (estimated horse power): 800

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3. 400EHP hydraulic press machine

This is a manual control machine. In this machine hydraulic pressure is used for

bending operation.

Description:

Material handled: usually S.S. and M.S.

Job handled: bending and straightening of plate up to 130mm thick at angle according to the job requirement.

EHP (estimated horse power): 400

Cutting section:

In this section, cutting operation is performed on various machines according to the job requirement. The machine used and their introduction is given below:

1. CNC flame cutting machine

As the name given, this is a computer numerical control machine. A program is feed in the machine and then according to the job requirement, data is given by the operator. And when machine is start, it cuts work piece automatically.

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Description:

Gas used: Oxy-acetylene

Material handled: mild steel

Cutting thickness: up to 220mm

Cutting speed: vary according to work piece thickness

2. CNC Air-plasma cutting machine

This is also a CNC cutting machine. Consumable electrode is used to produce arc and air is used to provide pressure for cutting. In this machine consumable electrode works as positive electrode and work piece as negative.

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Description:

Operating voltage: 240-260V

Operating current: 55-60A

Material handled: mild steel (M.S.), stainless steel (S.S.)

Cutting thickness: up to 150mm for M.S. and 50mm for S.S.

Cutting speed: vary according to work piece thickness

Gas used: oxygen

3. Manual plasma gas cutting machine

This is a manual control machine. Non-consumable electrode is used to produce arc and gas is used to provide pressure for cutting.In this machine non-consumable electrode works as positive electrode and work piece as negative. Mainly various cross-sections are cut by this machine.

Description:24

Material handled: stainless steel (S.S.)

Cutting thickness: up to 50mm

Cutting speed: vary according to work piece thickness

Gas used: Argon with pressure up to 8Kg

4. Universal gas cutting machine (UGC machine)

This is a manual control machine.

Description:

Material handled: mild steel (M.S.)

Cutting thickness: up to 150mm

Cutting speed: vary according to work piece thickness

Gas used: Oxy-acetylene

5. CNC shearing machine

This is a semi-automatic machine. Cutting is done through a blade. Thickness and length of cutting is provided by the operator through manual programming according to the job requirement.

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Description:

Material handled: mild steel (M.S.), stainless steel (S.S.)

Cutting thickness: 5-16mm for M.S. and 3-8mm for S.S.

Cutting speed: vary according to work piece thickness

Tool material: High carbon steel (HCS)

Other machines:

1. Straightening machine:

Various materials’ plate can be straightened through rolling pressure produced by 50hp motors. And the pressure is varied by a gear box.

Description:

Material handled: usually M.S., S.S., Cu and other

Straightening Thickness: 3-50mm plate are handled

Number of motor used: 2

2. Edge planer machine:

In this machine edge planning operation (V-shape, chamfering) can be done up to 10 meter length with 6-80mm thick or deep shape at any angle. For these operations hydraulic and manual jack pressure is used to hold the job and one tool is used for cutting as in lathe machine.

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3. Furnace:

The jobs are heated into the furnace for easy working and to give desired shape usually rolled section.

Fettling section:

In this section the various operations are performed on the job. This section includes of operations like grinding, fitting, cleaning etc.

Assembly and welding section, Bay-II

It has following sections-

a) Assembly and welding section for large size units up to 75 tons.

b) Heat treatment section.

c) Shot blasting and cleaning section.

The various machines that are used in different section in this Bay are followed:

Rolling section:

1. 3-roll bending machine:

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This is a manual control machine. The machine rollers are run through a gear mechanism powered by a heavy motor.

Description:

Maximum working length: 8000mm

Minimum working length: 1300mm

Maximum thickness of plate that can be roll: 32mm

Upper roll diameter: 750mm

Lower roll diameter: 680mm

Speed of forming: 5meter per minute

2. 4-roll bending machine:

This is a manual control hydraulic pressure based machine. The machine rollers are run through a gear mechanism powered by a heavy motor.

Description:

Maximum working length: 3800mm

Bending is done through side roller

No end bending required

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Welding section:

1. MIG welding:

Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. A constant voltage, direct current power source is most commonly used with GMAW, but constant current systems, as well as alternating current, can be used.

2. TIG welding:

Gas tungsten arc welding (GTAW), or tungsten inert gas (TIG) welding is a manual welding process that uses a non-consumable tungsten electrode, an inert or semi-inert gas mixture, and a separate filler material. Especially useful for welding thin materials, this method is characterized by a stable arc and high quality welds, but it requires significant operator skill and can only be accomplished at relatively low speeds. GTAW can be used on nearly all weldable metals, though it is most often applied to stainless steel and light metals. It is often used when quality welds are extremely important, such as in bicycle, aircraft and naval applications.

3. Electric arc welding:

These processes use a welding power supply to create and maintain an electric arc between an electrode and the base material to melt metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding region is sometimes protected by some type of inert or semi-inert gas, known as a shielding gas, and filler material is sometimes used as well.

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4. Electro slag welding:

Electro slag welding (ESW) is a highly productive, single pass welding process for thick (greater than 25mm up to about 300mm) materials in a vertical or close to vertical position. (ESW) is similar to electro gas welding, but the main difference is the arc starts in a different location. An electric arc is initially struck by wire that is fed into the desired weld location and then flux is added. Additional flux is added until the molten slag, reaching the tip of the electrode, extinguishes the arc. The wire is then continually fed through a consumable guide tube (can oscillate if desired) into the surfaces of the metal work pieces and the filler metal are then melted using the electrical resistance of the molten slag to cause coalescence. The wire and tube then move up along the work piece while a copper retaining shoe that was put into place before starting (can be water cooled if desired) is used to keep the weld between the plates that are being welded. Electro slag welding is used mainly to join low carbon steel plates and/or sections that are very thick. It can also be used on structural steel if certain precautions are observed. This process uses a direct current (DC) voltage usually ranging from about 600A and 40-50V; higher currents are needed for thicker materials. Because the arc is extinguished, this is not an arc process.

5. Submersed arc welding:

Submerged arc welding (SAW) is a high-productivity welding method in which the arc is struck beneath a covering layer of flux. This increases arc quality, since contaminants in the atmosphere are blocked by the flux. The slag that forms on the weld generally comes off by itself, and combined with the use of a continuous wire feed, the weld deposition rate is high. Working conditions are much improved over other arc welding processes, since the flux hides the arc and almost no smoke is produced. The process is commonly used in industry, especially for large products and in the manufacture of welded pressure vessels.

6. Oxy-acetylene welding:

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The most common gas welding process is oxyacetylene welding, also known as oxy fuel welding. The equipment is relatively inexpensive and simple, generally employing the combustion of acetylene in oxygen to produce a welding flame temperature of about 3100 °C. The flame, since it is less concentrated than an electric arc, causes slower weld cooling, which can lead to greater residual stresses and weld distortion, though it eases the welding of high alloy steels.

Other machines:

1. Shot blasting machine:

Basically this is a cleaning machine where scale formation is removed from the work pieces through the manual shot of steel spherical ball of 1mm diameter. These balls are pressurized by a motor blades running with 200rps; these blades forces the shots towards the work piece.

2. 2MW Furnace:

This is an electric coil furnace with 12 zones. In this furnace the jobs are heated up to 1200 ͦ C so that all the impurities present over the surface of the job removed.

Description:

Length of furnace: 10meters

Width of furnace: 4/5meters

Height of furnace: 4meters

Furnace zone: 12

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Power: 1960KW

Sections in Bay-III

It has following sections-

a) Assembly and welding section of small size units up to 1 tons.

b) Pipe sections.

The various machines that are used in different section in this Bay are followed:

Welding section:

In this section the various types of welding is done on the jobs. These welding are same as used in Bay-II but the difference is that here it is done one the small size jobs.

Fettling section:

In this section mainly fitting operation is done. Also some other types of operation like grinding, cleaning, finishing are also done on the jobs.

Cleaning and painting section:

In this section mainly the cleaning operation is done on the finished jobs. This

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includes the operation like grinding etc. and some finishing operations. After the cleaning the painting is done on the jobs. The painting provides resistance to corrosion and improves visual properties.

Other machines:

1. 3-roll bending machine

This is a manual control machine. The machine rollers are run through a gear mechanism powered by a heavy motor. But this machine is small as used in Bay-II.

Description:

Maximum working length: 2100mm

Maximum thickness of plate that can be roll: 16mm

Upper roll diameter: 250mm

Lower roll diameter: 225mm

Minimum bending radius: 220mm

Speed of forming: 6 to 8 minute

2. Saw:

This is a power saw which uses the mechanical power for cutting. Here, mainly

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pipes are cut.

3. Single axis CNC pipe bending machine:

It is an automatic machine which uses the hydraulic pressure for bending operation. This machine can bend the pipes at various angles.

Description:

Max bending radius: 500mm

Length over mandrel: 2meters

Max capacity: 114mm outer diameter and 7mm thick pipes.

HP: 15

4. Manual pipe bending machine:

This is a manual control machine. This machine is used for the bending of pipes of large radius and of large thickness.

5. Furnace:

There are two furnaces both the furnace are electric coil furnace with maximum temperature of 1300 ͦ C. These furnaces are used to heat the pipes which are going to be bent.

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6. CNC 6-spindle drilling machine:

It is an automatic machine. This machine is also known as CNC multi spindle drilling machine. As the name suggest, this machine consist of 6 drilling spindle which have computerized control. These drill can work independent of each other by means of different rpm, different pressure etc. Here, condenser main to plate and support to plate are worked. In this machine mainly drilling and reaming operation are performed.

7. Horizontal ram boring machine:

It is a numerical control machine. This machine uses the single point tool for operation. Both boring and counter boring operation are performed on this machine.

Description:

Tool material: HSS

Spindle diameter: 250mm

Max boring depth with spindle: 2000mm

Max extension of ram: 1500mm

Vertical feed: 4150mm

Spindle centre from bed: 670mm

RPM: 1 to 800

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Total power I/P: 150KW

Floor area: 6400mm * 14300 mm

Sections in Bay-IV

It has following sections-

a) Machine section: It is designed for machining parts and units during fabrication stage. This section supplies small parts and units of steam turbine, generators, hydro-turbines etc.

The unique machines viz. CNC multi spindle drilling machines and horizontal ram border are installed to help in machining of various components like drilling of tube plates of different types apart from machining of assemblies such as front wall, casings, water boxes etc.

b) Diaphragm section: Welded diaphragms of steam turbines are assembled, welded and stress relieved in this section.

c) Coolers section: In this section tubes of coolers are cut to the required size, then turned and thereafter winding and soldering of spirals on tubes is carried out by automatic machine. These are then assembled to form coolers which are then assembled and hydraulically tested.

The various machines that are used in different section in this Bay are followed:

Drilling section: 36

1. Radial drilling machines :

Here, these machines are five in numbers. All the machines differ from each other due to their power. Mainly taping and drilling operations are performed on these machines. These machines can do the hole from 5mm diameter to approx 150 mm diameter holes.

Coiling and cooler section:

1. Tinning machine:

This machine is also called as polishing machine. Here tinning is done on the

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copper pipes which are going for coiling. In this machine, firstly pipe cleaned with Zn-acid by washing then pipe is heated and send to tinning bath where the temperature is about 400 ͦ C, after then it is send to buffer where extra tinning is removed, and then pipe is cooled by water.

2. Coiling machine:

This is a manual machine which performs the coiling operation. The main purpose of coiling is that when water flow through these pipes at very high pressure and high speed, thus this process improves the strength of pipe. Also this process increases the surface area for cooling of gas as it is used in coolers.

Description:

Pipe material: copper

Wire material: copper

Pipe diameter: 19mm

Coil diameter: 33mm, 39mm, 44mm

Wire diameter: 0.9mm for 33mm diameter coiling, 0.69mm for 39mm and 44 mm diameter coiling

Marking section:

In this section, very accurate marking is done on the work pieces that are going to

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be worked. Choke is painted on the work pieces to improve the visual condition of work pieces. The tools used in this section are following:

1. Calipers

2. Vernier height gauge

3. Punches

4. Dividers

5. Hammer

6. Template plate

Etc.

Other machines:

1. Milling machines:

There are two type of milling machines are used first horizontal milling machine and second vertical milling machine. Here mainly the surface cutting operation is done on the small size work pieces.

Description:

Tool material: carbide

Metal worked: mainly mild steel and stainless steel

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Max rpm: 518 to 635 for vertical and 1075 to 1270 for horizontal

Min rpm: 35 to 40 for vertical and 68 to 80 for horizontal

2. Horizontal boring machines:

These machines are two in numbers. Mainly boring operation is performed in this machine. During operation the job is fixed and tool is moved in this machine. This machine uses the single head tool.

Description:

Tool material: carbide

Table movement: horizontally, vertically and circular

Cutting speed: according to working material and machine tool, rpm, feed

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3. Vertical boring machines:

These machines are three in numbers. This machine can do all the operations that can be done on a lathe machine. In this machine tool is fixed and job is moving. The tool is double head and the cutting can be done at any angle.

4. Planer machines:

Mainly the planning operation is done on these machine but some other operations like taper planning or chamfering, surface finishing, taper cut, slot cut, groove cut etc. are also done. These machines use the one direction cut with quick return mechanism. During operation the tool is fixed and the job is move in this machine. These machines use both the single point tool and multi point tool.

5. Lathe machines:

All the lathe machine that are used here are central axis lathes. Here these machines use the carbide tool for cutting and other operations. These machines are of different size, different power and also their table is different.

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Manufacturing processes:

Manufacturing starts with preparation of individual parts before assembly, in Bay-I.

a) The metal is first marked and cut by the following machines:

Guillotine shearing machine for cutting and trimming steel sheets and plates up to 25mm thick with straight contours.

Stationary and portable oxy-acetylene cutting machines for cutting parts out of steel plates.

A unique flame cutting machine is used for cutting steel plates by CNC programming.

CNC plasma cutting M/c for cutting stainless steel & higher alloys.

Combination punch, shear and bar cutters, circular saws and bar shears are used for cutting angles, shapes, flats and rods.

b) Straightening rollers are used for straightening plates and large sized blanks and a160 ton friction press for straightening small sized blanks. A roll bending machine is used for straightening and bending rolled beams and angles.

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c) An 800 ton hydraulic bending and 400 ton press and a 250 ton friction press are used for cold and hot bending from rolled sheets and shapes. Parts to bend are pre heated in a 700 KW electric furnace, when ever needed.

d) Finished parts are inspected at the working place.

After preparation is complete the next step is:

Assembly and welding: Processes used in Bay-II and III is as follows:

a) Components of units are assembled and tack welded for subsequent welding as per drawing and instructions on process cards.

b) Manual arc welding is employed in restricted and inaccessible places or where semi-automatic or automatic welding is not possible or has not been established.

c) Semi-automatic submerged arc welding, GTAW and Argon Carbon-di-oxide shielded arc welding are also used for increased productivity and better quality.

All assembly work is carried put on bed plates. Small size structures are welded with the help of manipulators.

Welding of high pressure cylinders of steam turbine is carried out after preliminary heating up to 250 ºc.

Heat treatment is carried out in electric furnaces of bogie hearth, bell and pit types after welding is completed.

In multi layer welding the roots of seams are gouged and then cleaned by mechanical means.

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All assembly and welding sections have connections for compressed air, oxygen& acetylene as well as Argon carbon-di-oxide mixture and water for semi automatic welding.

Weld quality inspection is adopted in accordance with the relevant specifications.

Inspection of weld quality and flow detection is carried out by means of X-ray machines, Gammagraphy machines of Cobalt and Iridium isotopes and ultrasonic flaw detectors.

Pressure vessel i.e. boilers, condensers, heaters and coolers undergo hydraulic test on special test beds meant for hydraulic testing. Kerosene leakage test is also done in case of thin walled vessels.

Process being followed in pipe section is mentioned below:

a) Pipes with diameter of 10-60mm and 38-108mm are cut on pipe cutting machine and oxy-acetylene cutters.

b) Cold bending of pipe is carried out on a pipe bending machine. Bending of carbon and alloy steel pipes of 114mm diameter and above is performed by heating them in electric furnaces and then by hot bending.

c) Facing of pipe and beveling for welding is carried out on a horizontal boring machine with portable type pipe chamfering machine.

d) For assembly and welding of pipes bed plates and manipulators are used.

e) Heat treatment of pipes is done in electric furnaces mentioned earlier.

f) Surface finishing is done manually or by shot blasting.

Pipe assemblies are dimensionally checked and quality of welds is tested by X-ray

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and Gammagraphy.

Process being followed in machining section is as follows:

a) Casting, forging, rolled section and welded structures are delivered to sections where assembly and welding are done in accordance with specifications set forth in drawings.

b) Pre-weld machining for large sized parts for steam turbine and hydro turbines are carried out in block-III.

c) Provision is made for the application of highly productive cemented carbide-tipped cutting tools, high speed cutting with maximum utilization of machine tool capacity and rapid section locating and clamping fixtures.

Painting section:

Process involved in painting section is as follows.

a) Painting materials used and painting processes adopted, conform to the standards for tropical climates.

b) Owing to different operating conditions and decoration requirements of units and parts of turbine sand electrical machines, different processes for painting are adopted.

BIBLIOGRAPHY

www.google.com

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BHEL Manuals(for company profile)

Wikipedia search engine

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