DECLARATION I, …………….., B Tech (3 rd 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 1
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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)
1
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.
2
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 &
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.
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.
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.
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.
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.