INDUSTRIAL TRAINING REPORT

(JUNE – JULY 2016)

Submitted in partial fulfilment of the requirements

Of the degree of

Bachelor of Technology

In

Mechanical Engineering

By

(SHRAWAN KUMAR)(1303540102)

(Department of Mechanical Engineering)

BABU BANARSI DAS INSTITUTE OF TECHNOLOGY

GHAZIABAD

2013-2017

ACKNOWLEDGEMENT

“An engineer with only theoretical knowledge is not a completeEngineer. Practical knowledge is very important to develop and apply engineering skills”. It gives me a great pleasure to have an opportunity to acknowledge and to express gratitude to those who were associated with me during my training at BHEL.I am very grateful to Mr. ROHIT AZMANI for providing me with an opportunity to undergo training under his able guidance.Furthermore, special thanks to Mr. Raj Singh for his help and support in Haridwar. Last, but not the least, I would also like to acknowledge the support of my college friends, who pursued their training with me. We shared some unforgettable moments together.I express my sincere thanks and gratitude to BHEL authorities for allowing me to undergo the training in this prestigious organization. I will always remain indebted to them for their constant interest and excellent guidance in my training work, moreover for providing me with an opportunity to work and gain experience.

THANK YOU

ABSTRACT

In the era of Mechanical Engineering, Turbine, A Prime Mover ( Which uses the Raw Energy ofa substance and converts it to Mechanical Energy) is a well known Machine most useful in thethe field of Power Generation. This Mechanical energy is used in running an Electric Generatorwhich is directly coupled to the shaft of turbine. From this Electric Generator, we get electricPower which can be transmitted over long distances by means of transmission lines andtransmission towers.In my Industrial Training in B.H.E.L., Haridwar I go through all sections in TurbineManufacturing. First management team told me about the history of industry, Area, Capacity,Machines installed & Facilities in the Industry.After that they told about the Steam Turbine its types , parts like Blades, Casing, Rotor etc. Thenthey told full explanation of constructional features and procedure along with equipement used.Before telling about the machines used in Manufacturing of Blade, they told about the safetyprecautions, Step by Step arrangement of machines in the block with a well defined properformat. They also told the material of blade for a particular desire, types of Blades, Operationsperformed on Blades, their New Blade Shop less with Advance Technology like CNC ShapingMachine.I would like to express my deep sense of Gratitude and thanks to MR. ROHIT AZMANIin charge of training in Turbine Block in B.H.E.L., Haridwar. Without the wise counsel and ableguidance, it would have been impossible to complete the report in this manner. Finally, I amindebted to all who so ever have contributed in this report and friendly stay at Bharat HeavyElectricals Limited (BHEL).

INDEX ACKNOWLEDGEMENT

ABSTRACT

SR NO TOPIC PAGE NO.

1. INTERODUCTION

2. BHEL-AN OVERVEIW

3. STEAM TURBINE

4. TYPES OF STEAM TURBINE

5. BHEL UNITS

6. BHEL HARIDWAR

7. TURBINE PARTS

8. MANUFACTURING PROCESS

9. BLADE SHOP

10. CONCLUSION

INTRODUCTIONBHEL 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 since1971-72.

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 14001certification for environment management. The company’s inherent potential coupled with its strong performance make this one of the “NAVRATNAS”, which is supported by the government in their endeavor to become future global players

B.H.E.L- An OverviewBHEL or the Bharat Heavy Engineering Limited is one of the largest engineering and manufacturing organizations in the country and theBHEL, Haridwar is their gift to Uttaranchal. With two large manufacturing plants, BHEL in Haridwar is among the leading industrial organizations in the state. It has established a Heavy Electrical Equipment Plant or HEEP and a Central Foundry Forge Plant or CFFP in Haridwar.The Heavy Electrical Equipment Plant in Haridwar designs andmanufactures turbo generators, AC and DC motors, gas turbines and huge steams. The Central Foundry Forge Plant in Haridwar deals withsteel castings and manufacturing of steel forgings.The BHEL plants in Haridwar have earned the ISO - 9001 and 9002 certificates for its high quality and maintenance. These two units have also earned the ISO - 14001 certificates. Situate in Ranipur near Haridwar, the Bharat Heavy Engineering Limited employs over 8,000 people.

BHEL is an integrated power plant equipment manufacturer and oneof the largest engineering and manufacturing companies in India in terms of turnover. BHEL was established in 1964, ushering in the indigenous Heavy Electrical Equipment industry in India - a dream that has been more than realized with a well-recognized track record of performance. The company has been earning profits continuously since 1971-72 and paying dividends since 1976-77 .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, Renewable Energy, Oil & Gas and Defence. BHEL has 15 manufacturing divisions, two repair units, four regional offices, eight service centres, eight overseas offices and15 regional centres and currently operate at more than 150 projectsites across India and abroad. BHEL places strong emphasis oninnovation and creative development of new technologies. Ourresearch and development (R&D) efforts are aimed not only atimproving the performance and efficiency of our existing products,but also at using state-of-the-art technologies and processes todevelop new products. This enables us to have a strong customerorientation, to be sensitive to their needs and respond quickly to the changes in the market.The high level of quality & reliability of our products is due toadherence to international standards by acquiring and adapting some of the best technologies from leading companies in the world including General Electric Company, Alstom SA, Siemens AG and Mitsubishi Heavy Industries Ltd., together with technologies developed in our own R&D centres. Most of our manufacturing units and other entities have been accredited to Quality Management Systems (ISO 9001:2008), Environmental Management Systems (ISO 14001:2004) and Occupational Health & Safety Management Systems (OHSAS 18001:2007).

BHEL has a share of around 59% in India's total installed generating capacity contributing 69% (approx.) to the total power generated fromutility sets (excluding non-conventional capacity) as of March 31, 2012. We have been exporting our power and industry segment products and services for approximately 40 years. We have exported our products and services to more than 70 countries. We had cumulatively installed capacity of over 8,500 MW outside of India in 21 countries, including Malaysia, Iraq, the UAE, Egypt and New Zealand. Our physical exports range from turnkey projects to after sales services.

BHEL work with a vision of becoming a world-class engineeringenterprise, committed to enhancing stakeholder value.Our greatest strength is our highly skilled and committed workforce of over 49,000 employees. Every employee is given an equal opportunity to develop himself and grow in his career. Continuous training and retraining, career planning, a positive work culture and participative style of management - all these have engendered development of a committed and motivated workforce setting new benchmarks in terms of productivity, quality and responsiveness.

STEAM TURBINE

A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion.Its modern manifestation was invented by Sir Charles Parsons in 1884. It has almost completely replaced the reciprocating piston steam engine primarily because of its greater thermal efficiency and higher power-to-weight ratio. Because the turbine generates rotary motion, it is particularly suited to be used to drive an electrical generator – about80% of all electricity generation in the world is by use of steamturbines. The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency through the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible process.

ADVANTAGES:-

Ability to utilize high pressure and high temperature steam. High efficiency. High rotational speed. High capacity/weight ratio. Smooth, nearly vibration-free operation. No internal lubrication. Oil free exhausts steam.

DISADVANTAGES:-For slow speed application reduction gears are required. The steam turbine cannot be made reversible. The efficiency of small simple steam turbines is poor.

STEAM TURBINES THE MAINSTAY OF BHEL:- BHEL has the capability to design, manufacture and commission steam turbines of up to 1000 MW rating for steam parameters ranging from 30 bars to 300 bars pressure and initial & reheat temperatures up to 600ºC.

Turbines are built on the building block system, consisting of modules suitable for a range of output and steam parameters.

For a desired output and steam parameters appropriate turbine blocks can be selected.

Types

These arrangements include single casing, tandem compound and crosscompound turbines. Single casing units are the most basic style where a single casing and shaft are coupled to a generator. Tandem compound are used where two or more casings are directly coupled together to drive a single generator. A cross compound Steam turbines are made in a variety of sizes ranging from small 1 hp (0.75 kW) units (rare) used as mechanical drives for pumps, compressors and other shaft driven equipment, to 2,000,000 hp (1,500,000 kW) turbines used to generate electricity. There are several classifications for modern steam turbines.

Steam Supply and Exhaust ConditionsThese types include condensing, non-condensing, reheat, extraction andinduction. Non-condensing or backpressure turbines are most widely used for process steam applications. The exhaust pressure is controlled by a regulating valve to suit the needs of the process steam pressure. These are commonly found at refineries, district heating units, pulp and paper plants, and desalination facilities where large amounts of low pressure process steam are available. Condensing turbines are most commonly found in electrical power plants. These turbines exhaust steam in a partially condensed state, typically of a quality near 90%, at a pressure well below atmospheric to a condenser.Reheat turbines are also used almost exclusively in electrical power plants. In a reheat turbine, steam flow exits from a high pressure section of the turbine and is returned to the boiler where additional superheat is added. The steam then goes back into an intermediate pressure section of the turbine and continues its expansion.

Casing or Shaft ArrangementsTurbine arrangement features two or more shafts not in line driving two or more generators that often operate at different speeds. A cross compound turbine is typically used for many large applications.

Principle of Operation and DesignAn ideal steam turbine is considered to be an isentropic process, or constant entropy process, in which the entropy of the steam entering the turbine is equal to the entropy of the steam leaving the turbine. No steam turbine is truly “isentropic”, however, with typical isentropic efficiencies ranging from 20%- 90% based on the application of the turbine. The interior of a turbine comprises several sets of blades, or “buckets” as they are more commonly referred to. One set of stationary blades is connected to the casing and one set of rotating blades is connected to the shaft. The sets intermesh with certain minimum clearances, with the size and configuration of sets varying to efficiently exploit the expansion of steam at each stage.

Turbine Efficiency

To maximize turbine efficiency, the steam is expanded, generating work, in a number of stages. These stages are characterized by how the energy is extracted from them and are known as impulse or reaction turbines. Most modern steam turbines are a combination of the reaction and impulse design. Typically, higher pressure sections are impulse type and lower pressure stages are reaction type.

Impulse Turbines

An impulse turbine has fixed nozzles that orient the steam flow into high speed jets. These jets contain significant kinetic energy, which the rotor blades, shaped like buckets, convert into shaft rotation as the steam jet changes direction. A pressure drop occurs across only the stationary blades, with a net increase in steam velocity across the stage.Reaction TurbinesIn the reaction turbine, the rotor blades themselves are arranged to formconvergent nozzles. This type of turbine makes use of the reaction force

produced as the steam accelerates through the nozzles formed by the rotor. Steam is directed onto the rotor by the fixed vanes of the stator. It leaves the stator as a jet that fills the entire circumference of the rotor. The steam then changes direction and increases its speed relative to the speed of the blades. A pressure drop occurs across both the stator and the rotor, with steam accelerating through the stator and decelerating through the rotor, with no net change in steam velocity across the stage but with a decrease in both pressure and temperature.

DIFFERENCES BETWEEN IMPULSE AND REACTION TURBINE

BHEL HARIDWAR

1. LOCATION

It is situated in the foot hills of Shivalik range in Haridwar. The main administrative building is

at a distance of about 8 km from Haridwar.

2. ADDRESS

Bharat Heavy Electrical Limited (BHEL)

Ranipur, Haridwar PIN- 249403

3. AREA

BHEL Haridwar consists of two manufacturing units, namely Heavy Electrical Equipment Plant( HEEP) and Central Foundry Forge Plant (CFFP), having area

HEEP area:- 8.45 sq km

CFFP area:- 1.0 sq km

The Heavy Electricals Equipment Plant (HEEP) located in Haridwar, is one of the major

manufacturing plants of BHEL. The core business of HEEP includes design and manufacture of

large steam and gas turbines, turbo generators, hydro turbines and generators, large AC/DC

motors and so on.

Central Foundry Forge Plant (CFFP) is engaged in manufacture of Steel Castings:Up to 50 Tons

per Piece Wt & Steel Forgings: Up to 55 Tons per Piece Wt.

4. UNITS

There are two units in BHEL Haridwar as followed:

1) Heavy Electrical Equipment Plant (HEEP)2) Central Foundry Forge Plant (CFFP) 

TURBINE PARTS

1 TURBINE BLADES Cylindrical reaction blades for HP, IP and LP Turbines 3-DS blades, in initial stages of HP and IP Turbine, to reduce secondary losses. Twisted blade with integral shroud, in last stages of HP, IP and initial stages of LP turbines, to reduce profile and Tip leakage losses

o Free standing LP moving blades Tip sections with supersonic design.o Fir-tree rooto Flame hardening of the leading edgeo Banana type hollow guide bladeo Tapered and forward leaning for optimized mass flow distributiono Suction slits for moisture removal

2 TURBINE CASINGCasings or cylinders are of the horizontal split type. This is not ideal, as the heavy flanges of thejoints are slow to follow the temperature changes of the cylinder walls. However, for assemblingand inspection purposes there is no other solution. The casing is heavy in order to withstand thehigh pressures and temperatures. It is general practice to let the thickness of walls and flangesdecrease from inlet- to exhaust-end. The casing joints are made steam tight, without the use ofgaskets, by matching the flange faces very exactly and very smoothly. The bolt holes in theflanges are drilled for smoothly fitting bolts, but dowel pins are often added to secure exactalignment of the flange joint. Double casings are used for very high steam pressures. The highpressure is applied to the inner casing, which is open at the exhaust end, letting the turbineexhaust to the outer casings.

3 TURBINE ROTORSThe design of a turbine rotor depends on the operating principle of the turbine. The impulseturbine with pressure drop across the stationary blades must have seals between stationary bladesand the rotor. The smaller the sealing area, the smaller the leakage; therefore the stationaryblades are mounted in diaphragms with labyrinth seals around thes haft. This constructionrequires a disc rotor. Basically there are two types of rotor: DISC ROTORSAll larger disc rotors are now machined out of a solid forging of nickel steel; this should give thestrongest rotor and a fully balanced rotor. It is rather expensive, as the weight of the final rotor isapproximately 50% of the initial forging. Older or smaller disc rotors have shaft and discs madein separate pieces with the discs shrunk on the shaft. The bore of the discs is made 0.1% smallerin diameter than the shaft. The discs are then heated until they easily are slid along the shaft andlocated in the correct position on the shaft and shaft key. A small clearance between the discsprevents thermal stress in the shaft. DRUM ROTORSThe first reaction turbines had solid forged drum rotors. They were strong, generally wellbalanced as they were machined over the total surface. With the increasing size of turbines the

solid rotors got too heavy pieces. For good balance the drum must be machined both outside andinside and the drum must be open at one end. The second part of the rotor is the drum end coverwith shaft.

1. CONSTRUCTIONAL FEATURES OF A BLADEThe blade can be divided into 3 parts: The profile, which converts the thermal energy of steam into kinetic energy, with acertain efficiency depending upon the profile shape. The root, which fixes the blade to the turbine rotor, giving a proper anchor to the blade,and transmitting the kinetic energy of the blade to the rotor. The damping element, which reduces the vibrations which necessarily occur in the bladesdue to the steam flowing through the blades. These damping elements may be integralwith blades, or they may be separate elements mounted between the blades. Each of theseelements will be separately dealt with in the following sections.

1.1 H.P. BLADE PROFILESIn order to understand the further explanation, a familiarity of the terminology used is required.The following terminology is used in the subsequent sections.If circles are drawn tangential to the suction side and pressure side profiles of a blade, and theircenters are joined by a curve, this curve is called the camber line. This camber line intersects theprofile at two points A and B. The line joining these points is called chord, and the length of thisline is called the chord length. A line which is tangential to the inlet and outlet edges is called thebitangent line. The angle which this line makes with the circumferential direction is called thesetting angle. Pitch of a blade is the circumferential distance between any point on the profile

and an identical point on the next blade.

HIGH PRESSURE BLADE AIRFOIL PROFILE

1.2 CLASSIFICATION OF PROFILESThere are two basic types of profiles - Impulse and Reaction. In the impulse type of profiles, theentire heat drop of the stage occurs only in the stationary blades. In the reaction type of blades,the heat drop of the stage is distributed almost equally between the guide and moving blades.Though the theoretical impulse blades have zero pressure drop in the moving blades, practically,for the flow to take place across the moving blades, there must be a small pressure drop acrossthe moving blades also. Therefore, the impulse stages in practice have a small degree of reaction.These stages are therefore more accurately, though less widely, described as low-reaction stages.The presently used reaction profiles are more efficient than the impulse profiles at part loads.This is because of the more rounded inlet edge for reaction profiles. Due to this, even if the inletangle of the steam is not tangential to the pressure-side profile of the blade, the losses are low.However, the impulse profiles have one advantage. The impulse profiles can take a large heatdrop across a single stage, and the same heat drop would require a greater number of stages ifreaction profiles are used, thereby increasing the turbine length. The Steam turbines use theimpulse profiles for the control stage (1st stage), and the reaction profiles for subsequent stages.There are four reasons for using impulse profile for the first stage:

a) Most of the turbines are partial arc admission turbines. If the first stage is are action stage, thelower half of the moving blades do not have any inlet steam, and would ventilate. Therefore,most of the stage heat drop should occur in the guide blades.

b) The heat drop across the first stage should be high, so that the wheel chamber of the outercasing is not exposed to the high inlet parameters. In case of -4turbines, the inner casing partingplane strength becomes the limitation, and therefore requires a large heat drop across the 1st

stage.

c) Nozzle control gives better efficiency at part loads than throttle control.

d) The number of stages in the turbine should not be too high, as this will increase the length ofthe turbine.There are exceptions to the rule. Turbines used for CCPs, and BFP drive turbines do not have acontrol stage. They are throttle-governed machines. Such designs are used when the inletpressure slides. Such machines only have reaction stages. However, the inlet passages of suchturbines must be so designed that the inlet steam to the first reaction stage is properly mixed, andoccupies the entire 360 degrees. There are also cases of controlled extraction turbines where theL.P. control stage is an impulse stage. This is either to reduce the number of stages to make theturbine short, or to increase the part load efficiency by using nozzle control, which minimizesthrottle losses.

1.3 H.P. BLADE ROOTSThe root is a part of the blade that fixes the blade to the rotor or stator. Its design depends uponthe centrifugal and steam bending forces of the blade. It should be designed such that thematerial in the blade root as well as the rotor / stator claw and any fixing element are in the safelimits to avoid failure. The roots are T-root and Fork-root. The fork root has a higher loadcarryingcapacity than the T-root. It was found that machining this T-root with side grip is more

of a problem. It has to be machined by broaching, and the broaching machine available could nothandle the sizes of the root. The typical roots used for the HP moving blades for various steamturbine applications are

1) T-ROOT

2) T-ROOT WITH SIDE GRIP

2 L.P. BLADE PROFILESThe LP blade profiles of moving blades are twisted and tapered. These blades are used whenblade height-to-mean stage diameter ratio (h/Dm) exceeds 0.2.

2.1 LP BLADE ROOTSThe roots of LP blades are as follows:1) 2 Blading : a. The roots of both the LP stages in –2 type of LP Blading are T-roots.2) 3 Blading:a. The last stage LP blade of HK, SK and LK blades have a fork-root. SK bladeshave4-fork roots for all sizes. HK blades have 4-fork roots up to 56 size, wheremodified profiles are used. Beyond this size, HK blades have 3 fork roots. LKblades have 3-forkroots for all sizes. The roots of the LP blades of precedingstages are of T-roots.

2.2 DYNAMICS IN BLADEThe excitation of any blade comes from different sources. They are Nozzle-passing excitation: As the blades pass the nozzles of the stage, they encounterflow disturbances due to the pressure variations across the guide blade passage. Theyalso encounter disturbances due to the wakes and eddies in the flow path. These aresufficient to cause excitation in the moving blades. The excitation gets repeated atevery pitch of the blade. This is called nozzle-passing frequency excitation. The orderof this frequency =no. of guide blades x speed of the machine. Multiples of thisfrequency are considered for checking for resonance. Excitation due to non-uniformities in guide-blades around the periphery. These canoccur due to manufacturing inaccuracies, like pitch errors, setting angle variations,inlet and outlet edge variations, etc.For HP blades, due to the thick and cylindrical cross-sections and short blade heights, the naturalfrequencies are very high. Nozzle-passing frequencies are therefore necessarily considered, sinceresonance with the lower natural frequencies occurs only with these orders of excitation.In LP blades, since the blades are thin and long, the natural frequencies are low. The excitationfrequencies to be considered are therefore the first few multiples of speed, since the nozzlepassingfrequencies only give resonance with very high modes, where the vibration stresses arelow.The HP moving blades experience relatively low vibration amplitudes due to their thickersections and shorter heights. They also have integral shrouds. These shrouds of adjacent blades

butt against each other forming a continuous ring. This ring serves two purposes – it acts as asteam seal, and it acts as a damper for the vibrations. When vibrations occur, the vibration energyis dissipated as friction between shrouds of adjacent blades.For HP guide blades of Wesel design, the shroud is not integral, but a shroud band is riveted to anumber of guide blades together. The function of this shroud band is mainly to seat the steam. Insome designs HP guide blades may have integral shrouds like moving blades. The primaryfunction remains steam sealing.In industrial turbines, in LP blades, the resonant vibrations have high amplitudes due to the thinsections of the blades, and the large lengths. It may also not always be possible to avoidresonance at all operating conditions. This is because of two reasons. Firstly, the LP blades arestandardized for certain ranges of speeds, and turbines may be selected to operate anywhere inthe speed range. The entire design range of operating speed of the LP blades cannot be outsidethe resonance range. It is, of course, possible to design a new LP blade for each application, butthis involves a lot of design efforts and manufacturing cycle time. However, with the present-daycomputer packages and manufacturing methods, it has become feasible to do so. Secondly, thedriven machine may be a variable speed machine like a compressor or a boiler-feed-pump. Inthis case also, it is not possible to avoid resonance. In such cases, where it is not possible toavoid resonance, a damping element is to be used in the LP blades to reduce the dynamicstresses, so that the blades can operate continuously under resonance also. There may be bladeswhich are not adequately damped due to manufacturing inaccuracies. The need fora dampingelement is therefore eliminated. In case the frequencies of the blades tend towards resonance dueto manufacturing inaccuracies, tuning is to be done on the blades to correct the frequency. Thistuning is done by grinding off material at the tip (which reduces the inertia more than thestiffness) to increase the frequency, and by grinding off material at the base of the profile (whichreduces the stiffness more than the inertia) to reduce the natural frequency.

The damping in any blade can be of any of the following types:

a) Material damping: This type of damping is because of the inherent damping properties of thematerial which makes up the component.

b) Aerodynamic damping: This is due to the damping of the fluid which surrounds thecomponent in operation.

c) Friction damping: This is due to the rubbing friction between the component underconsideration with any other object.Out of these damping mechanisms, the material and aerodynamic types of damping are verysmall in magnitude. Friction damping is enormous as compared to the other two types ofdamping. Because of this reason, the damping elements in blades generally incorporate a featureby which the vibrational energy is dissipated as frictional heat. The frictional damping has aparticular characteristic. When the frictional force between the rubbing surfaces is very small ascompared to the excitation force, the surfaces slip, resulting in friction damping. However, whenthe excitation force is small when compared to the frictional force, the surfaces do not slip,resulting in locking of the surfaces. This condition gives zero friction damping, and only thematerial and aerodynamic damping exists. In a periodically varying excitation force, it may

frequently happen that the force is less than the friction force.During this phase, the damping is very less. At the same time, due to the locking of the rubbingsurfaces, the overall stiffness increases and the natural frequency shifts drastically away from theindividual value. The response therefore also changes in the locked condition. The resonantresponse of a system therefore depends upon the amount of damping in the system (which isdetermined by the relative duration of slip and stick in the system, i.e., the relative magnitude ofexcitation and friction forces) and the natural frequency of the system (which alters between theindividual values and the locked condition value, depending upon the slip or stick condition).

2.3 BLADING MATERIALSAmong the different materials typically used for blading are 403 stainless steel, 422 stainlesssteel, A-286, and Haynes Satellites Alloy Number 31 and titanium alloy. The403 stainless steel isessentially the industry’s standard blade material and, on impulse steam turbines, it is probablyfound on over 90 percent of all the stages. It is used because of its high yield strength, endurancelimit, ductility, toughness, erosion and corrosion resistance, and damping. It is used within aBrinell hardness range of 207 to 248 to maximize its damping and corrosion resistance. The 422stainless steel material is applied only on high temperature stages (between 700 and 900°F or371 and 482°C), where its higher yield, endurance, creep and rupture strengths are needed.The A-286 material is a nickel-based super alloy that is generally used in hot gas expanders withstage temperatures between 900 and 1150°F (482 and 621°C). The Haynes Satellites AlloyNumber 31 is a cobalt-based super alloy and is used on jet expanders when precision cast bladesare needed. The Haynes Satellite Number 31 is used at stage temperatures between 900 and1200°F (482 and 649°C). Another blade material is titanium. Its high strength, low density, andgood erosion resistance make it a good candidate for high speed or long-last stage blading.

3. MANUFACTURING PROCESS

3.1 INTRODUCTION

Manufacturing process is that part of the production process which is directly concerned with thechange of form or dimensions of the part being produced. It does not include the transportation,handling or storage of parts, as they are not directly concerned with the changes into the form ordimensions of the part produced. Manufacturing is the backbone of any industrialized nation.Manufacturing and technical staff in industry must know the various manufacturing processes,materials being processed, tools and equipments for manufacturing different components orproducts with optimal process plan using proper precautions and specified safety rules to avoidaccidents. Beside above, all kinds of the future engineers must know the basic requirements ofworkshop activities in term of man, machine, material, methods, money and other infrastructurefacilities needed to be positioned properly for optimal shop layouts or plant layout and othersupport services effectively adjusted or located in the industry or plant within a well plannedmanufacturing organization. Today’s competitive manufacturing era of high industrialdevelopment and research, is being called the age of mechanization, automation and computerintegrated manufacturing. Due to new researches in the manufacturing field, the advancementhas come to this extent that every different aspect of this technology has become a full-fledged

fundamental and advanced study in itself. This has led to introduction of optimized design andmanufacturing of new products. New developments in manufacturing areas are deciding totransfer more skill to the machines for considerably reduction of manual labor.

3.2 CLASSIFICATION OF MANUFACTURING PROCESSES

For producing of products materials are needed. It is therefore important to know thecharacteristics of the available engineering materials. Raw materials used manufacturing ofproducts, tools, machines and equipments in factories or industries are for providing commercialcastings, called ingots. Such ingots are then processed in rolling mills to obtain market form ofmaterial supply in form of bloom, billets, slabs and rods. These forms of material supply arefurther subjected to various manufacturing processes for getting usable metal products ofdifferent shapes and sizes in various manufacturing shops. All these processes used inmanufacturing concern for changing the ingots into usable products may be classified into sixmajor groups as Primary shaping processes Secondary machining processes Metal forming processes Joining processes Surface finishing processes and Processes effecting change in properties

3.2.1 PRIMARY SHAPING PROCESSES

Primary shaping processes are manufacturing of a product from an amorphous material. Someprocesses produces finish products or articles into its usual form whereas others do not, andrequire further working to finish component to the desired shape and size. The parts producedthrough these processes may or may not require to undergo further operations. Some of theimportant primary shaping processes are: Casting Powder metallurgy Plastic technology Gas cutting Bending and Forging

3.2.2 SECONDARY OR MACHINING PROCESSESAs large number of components require further processing after the primary processes. Thesecomponents are subjected to one or more number of machining operations in machine shops, toobtain the desired shape and dimensional accuracy on flat and cylindrical jobs. Thus, the jobsundergoing these operations are the roughly finished products received through primary shapingprocesses. The process of removing the undesired or unwanted material from the work-piece orjob or component to produce a required shape using a cutting tool is known as machining. Thiscan be done by a manual process or by using a machine called machine tool (traditionalmachines namely lathe, milling machine, drilling, shaper, planner, slotter).

In many cases these operations are performed on rods, bars and flat surfaces in machine shops.These secondary processes are mainly required for achieving dimensional accuracy and a veryhigh degree of surface finish. The secondary processes require the use of one or more machinetools, various single or multi-point cutting tools (cutters), jobholding devices, marking andmeasuring instruments, testing devices and gauges etc. forgetting desired dimensional controland required degree of surface finish on the work-pieces. The example of parts produced bymachining processes includes hand tools machine tools instruments, automobile parts, nuts, boltsand gears etc. Lot of material is wasted as scrap in the secondary or machining process. Some ofthe common secondary or machining processes are: Turning Threading Knurling Milling Drilling Boring Planning Shaping Slotting Sawing Broaching Hobbing Grinding Gear Cutting Thread cutting and Unconventional machining processes namely machining with Numerical control (NC)machines tools or Computer Numerical Control (CNC) machine tool using ECM,LBM, AJM, USM setups.

4. BLOCK 3 LAY-OUTTable 5: Lay-out of Block 35. CLASSIFICATION OF BLOCK 3

BAY-1 IS FURTHER DIVIDED INTO THREE PARTS

1. HMSIn this shop heavy machine work is done with the help of different NC &CNC machinessuch as center lathes, vertical and horizontal boring & milling machines. Asia’s largest verticalboring machine is installed here and CNC horizontal boring milling machines from Skoda ofCzechoslovakia.

2. Assembly Section (of hydro turbines)In this section assembly of hydro turbines are done. Blades of turbine are1st assemble onthe rotor & after it this rotor is transported to balancing tunnel where the balancing is done. Afterbalancing the rotor, rotor &casings both internal & external are transported to the customer. Total

assembly of turbine is done in the company which purchased it by B.H.E.L.

3. OSBT (Over Speed Balancing Tunnel)In this section, rotors of all type of turbines like LP(low pressure), HP(high pressure) &IP(Intermediate pressure) rotors of Steam turbine ,rotors of Gas & Hydro turbine are balanced .Ina large tunnel, Vacuum of 2 torr is created with the help of pumps & after that rotor is placed onpedestal and rotted with speed of 2500-4500 rpm. After it in a computer control room the axis ofrotation of rotor is seen with help of computer & then balance the rotor by inserting the smallbalancing weight in the grooves cut on rotor.

Fig 4: Over speed & Vacuum Balancing TunnelFor balancing and over speed testing of rotors up to 320 tons in weight, 1800 mm in length and6900 mm diameter under vacuum conditions of 1 Torr.

BAY –2 IS DIVIDED IN TO 2 PARTS:

1. HMSIn this shop several components of steam turbine like LP, HP & IP rotors, Internal & externalcasing are manufactured with the help of different operations carried out through different NC &CNC machines like grinding, drilling, vertical & horizontal milling and boring machines, centerlathes, planer, Kopp milling machine.

2. Assembly SectionIn this section assembly of steam turbines up to 1000 MWIs assembled. 1st moving blades areinserted in the grooves cut on circumferences of rotor, then rotor is balanced in balancing tunnelin bay-1.After is done in which guide blades are assembled inside the internal casing & thenrotor is fitted inside this casing. After it this internal casing with rotor is inserted into theexternal.

BAY 3 IS DIVIDED INTO 3 PARTS:

1. Bearing SectionIn this section Journal bearings are manufactured which are used in turbines to overcomethe vibration & rolling friction by providing the proper lubrication.

2. Turning SectionIn this section small lathe machines, milling & boring machines, grinding machines &drilling machines are installed. In this section small jobs are manufactured like rings, studs, disksetc.

3. Governing SectionIn this section governors are manufactured. These governors are used in turbines forcontrolling the speed of rotor within the certain limits. 1st all components of governor are madeby different operations then these all parts are treated in heat treatment shop for providing thehardness. Then these all components are assembled into casing. There are more than 1000components of Governor.

BAY-4 IS DIVIDED INTO 3 PARTS:

1. TBM (Turbine Blade Manufacturing) ShopIn this shop solid blade of both steam & gas turbine are manufactured. SeveralCNC & NC machines are installed here such as Copying machine, Grinding machine, Rhomboidmilling machine, Duplex milling machine, T- root machine center, Horizontal tooling center,Vertical & horizontal boring machine etc.

Fig 5. Steam Turbine Casing & Rotors in Assembly Area

2. Turning SectionSame as the turning section in Bay-3, there are several small Machine like lathesmachines, milling, boring, grinding machines etc.

Fig 6. CNC Rotor Turning Lathe

3. Heat Treatment ShopIn this shop there are several tests performed for checking the Hardness of differentcomponents. Tests performed are Sereliting, Nitriding, DP Test.

5. BLADE SHOP

Blade shop is an important shop of Block 3. Blades of all the stages of turbine are made in thisshop only. They have a variety of centre lathe and CNC machines to perform the completeoperation of blades. The designs of the blades are sent to the shop and the Respective job isdistributed to the operators. Operators perform their job in a fixed interval of time.

5.1 TYPES OF BLADES

Basically the design of blades is classified according to the stages of turbine. The size of LPTURBINE BLADES is generally greater than that of HP TURBINE BLADES. At the first T1,T2, T3 & T4 kinds of blades were used, these were 2nd generation blades. Then it was replacedby TX, BDS (for HP TURBINE) & F shaped blades. The most modern blades are F & Z shapedblades.Cylindrical ProfileTX BladeHP/IP Intermediate stages& LP Initial3 Dimesional3DS BladeHP/IP Initial StagesTwisted ProfileF BladeHP/IP Rear Stages

Fig. 7 Types Of Blades

5.2 OPERATIONS PERFORMED ON BLADESSome of the important operations performed on blade manufacturing are:- Milling Blank Cutting Grinding of both the surfaces Cutting Root milling

5.3 MACHINING OF BLADESMachining of blades is done with the help of Lathe & CNC machines. Some of the machinesare:- Centre lathe machine Vertical Boring machine Vertical Milling machine CNC lathe machineFig 8. Schmetic Diagram of a CNC Machine

5.4 NEW BLADE SHOPA new blade shop is being in operation, mostly 500mw turbine blades are manufactured in thisshop. This is a highly hi tech shop where complete manufacturing of blades is done using singleadvanced CNC machines. Complete blades are finished using modernized CNC machines. Someof the machines are:- Pama CNC ram boring machine. Wotum horizontal machine with 6 axis CNC control. CNC shaping machine.

Fig 9. CNC Shaping Machine

6. CONCLUSIONGone through 1 month training under the guidance of capable engineers and workers ofBHEL Haridwar in Block-3 “TURBINE MANUFACTURING” headed by Senior Engineer ofdepartment Mr. ROHIT AZMANI situated in Ranipur, Haridwar,(Uttarakhand).The training was specified under the Turbine Manufacturing Department. Working under thedepartment I came to know about the basic grinding, scaling and machining processes which wasshown on heavy to medium machines. Duty lathes were planted in the same line where thespecified work was undertaken.The training brought to my knowledge the various machining and fabrication processes went notonly in the manufacturing of blades but other parts of the turbine.