ATrainingreportOn

AtBHELHARIDWAR

Submitted in partialfulfillment ofrequirementsfor the degreeofBachelor of TechnologyInMATERIAL SCIENCE WITH SPECILIZATION IN NANOTECHOLOGY

Submitted by: - Guided by:-Akriti Agrawal ACKNOWLEDGEMENTInspiration and motivation havealwaysplayed akeyrolein the successofany venture.A vocational training is a golden opportunity for learning and self development. I consider myself very lucky and honored to have so many wonderful people lead me through in completion of this project.Iamalso gratefulto themanagement of Bharat Heavy Electricallimited (BHEL),Haridwar forpermitting me to havetraining during May21st to June 20th 2015.My thanks and appreciations also go to my co-trainees at BHEL who have willingly helped me out with their abilities and their constructive feedback. For their friendly support that created an environment in which work was very enjoyable.Lastly, I thank almighty, my parents for their constant encouragement without which this assignment would not be possible.The direction,advice, discussion and constant encouragementgiven by themhasbeen so help fullin completing theworksuccessfully

Contents1.INTRODUCTION61.1.Working areas61.1.1.Power generation61.2.2. Powertransmission &distribution (T&D)61.2.3. Industries71.2.4. Transportation71.2.5. Telecommunication81.2.6.Renewable energy81.2.7. Internationaloperations81.3Human resourcedevelopment institute82.STEAMTURBINE102.1INTRODUCTION102.2. Advantages:-132.3 Disadvantages:-132.4Steamturbinesthemainstayof BHEL133.TYPESOF STEAMTURBINE143.1Impulse turbine143.2Theimpulse principle153.3Reaction principle153.4Impulse turbine staging154. TURBINEPARTS164.1Turbine blades164.2Turbine casing164.3Turbine rotors175.BLADING MATERIALS176. MANUFACTURING PROCESS186.1Introduction186.2classification of manufacturing processes186.2.1Primaryshaping processes186.2.2Secondaryor machining processes187.BLOCK3LAY-OUTS197.1 Classification of block 3198. BLADESHOP228.1Types of blades238.2Operationsperformed on blades238.3Machining of blades238.4Newbladeshop2410. CONCLUSION24

Figure 1- Rotating Steam Turbine11Figure 2- Steam turbine rotor12Figure 3- Impulse turbine15Figure 4-Reaction turbine16Figure 5-steam turbine casing and rotors I assembly area22Figure 6-CNC rotor turning lathe22Figure 7- types of blades23Figure 8- Schematic diagram of a CNC machine24

1. INTRODUCTIONBHELis thelargest engineeringand manufacturingenterprisein India in the energy related infrastructuresector today. BHELwasestablished morethan40 years ago when its first plant wassetup in Bhopalushering in theindigenous Heavy Electrical Equipment Industry in Indiaadreamwhich has beenmorethanrealizedwith awell recognized track record ofperformance ithas been earning profits continuously since1971-72. BHELcaters to coresectors of the IndianEconomy viz.,Power Generation's &Transmission,Industry,Transportation,Telecommunication,RenewableEnergy, Defense, etc. Thewidenetwork ofBHEL's 14 manufacturingdivision, four power Sectorregional centers,over 150project sites, eight service centers and 18 regional offices, enablestheCompanyto promptly serve its customers andprovidethemwith suitable products, systems and services efficiently and at competitive prices. BHEL has already attained ISO9000 certification forquality management,and ISO14001certification for environment management. Thecompanys inherent potentialcoupled with its strong performance make this oneoftheNAVRATNAS, which is supportedbythegovernment intheir endeavor to become future globalplayers. TherearetwounitsinBHEL Haridwarasfollowed: Heavy Electrical Equipment Plant (HEEP), Central Foundry Forge Plant (CFFP).1.1.Working areas1.1.1. Power generation

Power generation sectorcomprises thermal, gas, hydroand nuclear power plant business as of 31.03.2001, BHELsupplied sets account for nearly 64737 MW or65%ofthetotalinstalled capacity of99,146 MWin the country, as against niltill1969-70.BHELhas proventurnkeycapabilities for executingpower projects fromconcept to commissioning, it possesses thetechnology and capability to produce thermalsets with supercriticalparametersup to 1000 MWunitrating and gas turbinegeneratorsets ofup to 240 MWunitrating.Co-generation and combined-cycle plants have been introduced to achievehigher plant efficiencies. to makeefficient useofthehigh-ash-content coal availableinIndia, BHELsupplies circulatingfluidizedbedcombustion boilers toboth thermal and combined cycle power plants.The companymanufactures235MWnuclearturbine generatorsetsandhas commenced production of500MW nuclear turbinegenerator sets. Custom made hydro setsofFrancis,Pelton and Kaplan types for different head discharge combination arealso engineering and manufactured by BHEL .In all,orders formore than 700 utility sets of thermal,hydro,gas and nuclear have beenplacedonthe Companyas ondate.The powerplantequipmentmanufacturedby BHELis based on contemporary technology comparable to the best in theworld and is alsointernationally competitive.TheCompany hasprovenexpertiseinPlant PerformanceImprovement through renovation modernization and upgrading ofa variety ofpower plant equipment besides specializedknow how ofresidual life assessment, health diagnostics and life extension ofplants.1.2.2. Powertransmission &distribution (T&D)

BHELoffer widerangingproducts and systems forT&D applications. Products manufacturedincludepower transformers, instrument transformers, dry type transformers,series and stunt reactor,capacitor tanks, vacuumand SFcircuit breakers gasinsulated switch gears andinsulators. Astrong engineering baseenablestheCompany to undertaketurnkey delivery ofelectric substancesup to 400 kVlevelseries compensation systems (forincreasing power transfer capacity oftransmission lines and improvingsystemstability and voltage regulation), shunt compensation systems (for power factor andvoltageimprovement) and HVDCsystems (for economic transfer ofbulkpower).BHELhas indigenously developed thestate-of-the-art controlledshunt reactor (for reactivepower management on long transmission lines).Presently a400 kVFacts (Flexible AC Transmission System) projectunder execution.1.2.3. Industries

BHELis a majorcontributor ofequipment and systems to industries. Cement, sugar, fertilizer, refineries, petrochemicals, paper, oil and gas, metallurgical and other process industries lines and improving systemstability and voltageregulation, shunt compensationsystems(forpowerfactorand voltageimprovement)and HVDCsystems(foreconomic transfer ofbulkpower)BHELhas indigenouslydeveloped thestate-of-the-art controlledshuntreactor (for reactivepower managementon longtransmission lines).Presently a400 kV FACTS (FlexibleAC Transmission System) projects is under execution. Therange ofsystem&equipment supplied includes: captive power plants,co-generation plantsDG power plants, industrialsteamturbines, industrial boilers and auxiliaries. Water heat recovery boilers, gasturbines, heat exchangers andpressure vessels, centrifugal compressors, electrical machines, pumps, valves, seamless steel tubes, electrostatic precipitators, fabric filters,reactors, fluidized bed combustion boilers, chemicalrecovery boilers and process controls.TheCompanyisamajor producerof large-sizethruster devices. Italsosupplies digitaldistributed controlsystems forprocess industries,and control&instrumentation systems forpower plant and industrialapplications. 1.2.4. Transportation

BHELis involved inthedevelopment design, engineering, marketing, production, installation,and maintenanceand after-sales service ofRolling Stock and traction propulsion systems. Intheareaof rollingstock,BHELmanufactures electric locomotivesupto 5000HP, diesel-electric locomotives from 350 HP to 3100 HP, both for mainline and shunting duly applications. BHELis also producing rollingstock for special applications viz.,overhead equipment cars, Special wellwagons, Rail-cum-roadvehicleetc.,Besides traction propulsion systems forin-houseuse,BHELmanufactures traction propulsion systems for other rollingstock producersof electric locomotives, electrical multipleunits and metro cars. Theelectric and dieseltraction equipment on India Railways are largely powered by electrical propulsion systems produced by BHEL.Thecompany also undertakes retooling and overhauling of rolling stock in thearea ofurban transportation systems. BHELis geared up to turnkey execution of electric trolley bus systems, light railsystems etc. 1.2.5. Telecommunication

BHELalso caters to Telecommunication sector by way ofsmall,mediumand large switching systems.1.2.6.Renewable energy

Technologiesthat canbeofferedbyBHELfor exploitingnon-conventional and renewable sources of energy include: wind electric generators, solar photo voltaic systems, solar lanterns and battery-powered road vehicles. TheCompany has takenup R&Defforts for development ofmulti-junction amorphous silicon solar cells and fuel based systems.1.2.7. Internationaloperations

BHELhas, over theyears, established its references in around 60countries ofthe world, ranging for theUnited States in thewest to New Zealand in theFar East. these references encompass almost the entire product range ofBHEL,covering turnkey power projectsof thermal, hydroandgas-basedtypes, substationprojects, rehabilitation projects, besides awidevariety ofproducts, like transformers, insulators, switchgears, heatexchangers, castingsand forgings, valves, well-headequipment, centrifugal compressors, photo-voltaic equipment etc. apart fromover 1110mw ofboiler capacity contributedin Malaysia, and execution of four prestigious power projects in Oman, some oftheother major successes achieved by the company have been in Australia, Saudi Arabia, Libya,Greece, Cyprus,Malta, Egypt, Bangladesh, Azerbaijan, SriLanka, Iraq etc.1.2 Technologyup gradation and research&development

Toremaincompetitiveandmeetcustomers'expectations,BHELlaysgreat emphasis on thecontinuous upgradation ofproducts andrelated technologies, and development ofnew products. TheCompany has upgraded its products to contemporary levels through continuous in house efforts as wellas through acquisition ofnew technologies from leading engineering organizations of the world.The Corporate R&DDivision at Hyderabad, spread over a 140 acre complex, leadsBHEL'sresearcheffortsinanumberofareasofimportance toBHEL'sproduct range.Research and product development centers at each ofthe manufacturing divisions play a complementary role. BHEL's Investment in R&Dis amongst thelargest in thecorporatesector in India.1.3Human resourcedevelopment institute

ThemostprizedassetofBHELisitsemployees.TheHumanResourceDevelopment Institute and other HRDcenters ofthe Company help in not only keeping their skills updatedand finely honedbut also in addingnew skills, whenever required. Continuous training and retraining, positive, a positive work culture and participative style ofmanagement have engendered development ofa committed and motivated workforce leading to enhanced productivity and higher levels ofquality.1.4. Health, safetyand environmentmanagement

BHEL,as an integral part ofbusiness performanceand in its endeavor ofbecoming aworld-classorganization and sharing thegrowing globalconcern on issues relatedto 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 Policieshavebeenformulated as:1.4.1. Environmentalpolicy

Compliancewith applicableEnvironmental Legislation/Regulation; ContinualImprovement in Environment Management Systems to protectour natural environment and ControlPollution; Promotion ofactivities forconservation ofresources by Environmental Management; EnhancementofEnvironmentalawareness amongstemployees,customers and suppliers. 1.4.2. Occupationalhealthand safetypolicy

Compliancewith applicable Legislation andRegulations; Settingobjectives andtargets to eliminate/control/minimizerisks dueto Occupationaland Safety Hazards; Appropriatestructuredtraining ofemployees on Occupational Health and Safety (OH&S) aspects; Formulation and maintenance of OH&SManagement programs forcontinual improvement; PeriodicreviewofOH&SManagementSystemtoensureitscontinuing suitability, adequacy and effectiveness; Communication of OH&S Policy to allemployees and interested parties. 1.4.3. Principles of the "globalcompact"HUMAN RIGHTS1. Business should support and respect the protection ofinternationally proclaimed human rights; 2. Make surethey are not complicitin human rightsabuses.LABOUR STANDARDS3. Business should uphold thefreedomofassociation andtheeffectiverecognition oftheright to collectivebargaining4. The elimination ofallformofforces and compulsory labor.5. .Theeffectiveabolitionof child labor, and6.Eliminatediscrimination.ENVIRONMENT7. Businesses shouldsupport a precautionaryapproach toenvironmentalchallenges.8. Undertakeinitiatives to promote greater environmentalresponsibility. 9. Encouragethedevelopment anddiffusion of environmentally friendly technologies.

2.STEAMTURBINE2.1INTRODUCTION

Aturbineis adevicethat converts chemicalenergy into mechanical energy, specifically when a rotor ofmultipleblades orvanes is driven by the movement ofa fluid orgas. In thecaseofa steamturbine, thepressureand flow ofnewly condensed steam rapidly turns the rotor.Thismovementis possible because thewater tosteamconversion results in a rapidly expanding gas. As theturbines rotorturns,therotating shaftcanwork to accomplish numerous applications, oftenelectricity generation.In a steamturbine,the steams energy is extracted through the turbineand the steam leaves theturbineat alower energy state. High pressure and temperature fluid at the in let oftheturbineexitaslowerpressure andtemperaturefluid.Thedifferenceisenergy converted bythe turbineto mechanicalrotationalenergy,lessanyaerodynamic and mechanicalinefficienciesincurred in theprocess. Sincethefluid is at alower pressureat the exit ofthe turbine than at the inlet, itis common tosay the fluid has been expanded acrosstheturbine. Becauseoftheexpanding flow,higher volumetric flow occurs at theturbineexit(at least for compressible fluids) leading to theneedfor larger turbineexit areas thanattheinlet.The generic symbolfor a turbine used in aflow diagramis shown in Figure below.Thesymboldivergeswith alarger areaat theexit thanattheinlet. This is how onecantella turbinesymbolfroma compressor symbol. In Figure, the graphic is colored to indicate the generaltrend of temperature drop through aturbine.In a turbine with ahigh inlet pressure, theturbinebladesconvert this pressure energy into velocity or kinetic energy,which causes the blades torotate.Many green cycles use a turbine in this fashion, althoughtheinlet conditions may not bethesameasfor a conventional high-pressure and temperature steamturbine.Bottoming cycles,for instance, extract fluid energy that is at alower pressure and temperature than aturbinein aconventional power plant.Abottoming cyclemightbe usedtoextractenergyfrom the exhaustgasesofa largediesel engine, but thefluid in abottomingcyclestill has sufficient energy to be extracted across a turbine,with the energy converted into rotationalenergy.

Figure 1- Rotating Steam Turbine Turbines also extract energy in fluid flow where the pressure is not high but where thefluid has sufficient fluid kinetic energy.Theclassic example is a windturbine, which converts thewinds kinetic energy to rotational energy.This typeofkinetic energy conversion is common ingreen energy cyclesfor applications ranging fromlarger wind turbines to smaller hydrokinetic turbines.Turbinescanbedesignedtoworkwellinvarietyfluids,including gasesand liquids, where they are used not only to drivegenerators, but also to drivecompressors orpumps .One common (and somewhat misleading) use of theword turbine is gas turbine,as in a gas turbineengine.Agas turbineengine is more than just a turbineand typically includes a compressor,combustor and turbinecombined to be a self-contained unitused to provide shaft or thrust power. Theturbine component inside the gas turbinestillprovidespower,butacompressorandcombustorarerequiredtomakeaself-contained systemthat needs only the fueltoburn in thecombustor. Anadditional usefor turbines in industrial applicationsthat mayalso be applicable in some green energy systems is to coola fluid.As previously mentioned, whena turbineextracts energy froma fluid, the fluid temperature is reduced.Some industries, such as the gas processing industry, use turbines as sources of refrigeration, dropping thetemperature of the gas going through theturbine. In other words, the primary purposeoftheturbineis to reducethetemperature of theworking fluid as opposed to providing power.Generally speaking, the higher thepressureratio across a turbine,the greater the expansion and the greater the temperature drop.Even where turbines are usedto coolfluids, theturbines stillproduce power and must be connected to a power absorbing device that is part of an overallsystem. Also notethat turbines in high inlet-pressureapplications are sometimes called expanders.Theterms turbine and expandercan beused interchangeably formost applications, but expander is not used when referring to kinetic energy applications,as thefluid does not gothrough significant expansion.

Turbines are of 3 types- 1. High pressure2. Low pressure3. Intermediate pressure

Figure 2- Steam turbine rotor

High pressure the high pressure turbine is a multi-layer, multi block structure that only converts water steam into shaft power. It is more efficient than the turbine and can support higher steam pressure input. High pressure turbine requires a high amount of water steam to operate efficiently and requires ramp up time for the lower end fins. Single flow Small size Double shell casing Inner casing vertically Outer casing bored type and axially divided Mono block rotor 1st stage diagonal blading Casing mounted valves Main steam pressure 247 ATA Main steam temperature 565 c Outlet steam pressure 54 ATA Number of stages -19 Power generated in HPT 197 MWIntermediate Pressure Double flow Double casing design with horizontal split Inlet from lower half Single exhaust from upper half Extractions connections from lower half Admission blade ring with cooling Reheat steam pressure 54ATA Reheat steam temperature 593 c Steam outlet pressure : 6.0ATA Power generation in IPT 262 MWLow turbine Double flow Big size Double shell casing Single admission from top half Outer casing and condenser rigidly connected Push rod arrangement to minimize axial clearness Mono block rotor Inner outer casing fabricated Inlet steam pressure 5.97 ATA Inlet steam pressure 282. 12 c Outlet steam pressure 0.1047ATA Power generated in LPT 210 MW After the steam has passed through the HP stage, it is returned to the boiler to be re- heated to its original temperature .Although the pressure remains greatly reduced. The reheated steam then passes through the IP stage and finally to the IP stage of the turbine. A single shaft or several shafts coupled together may be used.2.2. Advantages:-

Ability toutilize high pressure and high temperature steam. High efficiency. High rotational speed. High capacity/weight ratio. Smooth, nearly vibration-free operation. No internal lubrication. Oilfree exhausts steam.2.3 Disadvantages:-

For slow speed application reduction gears are required. Thesteamturbinecannot bemadereversible. Theefficiency ofsmallsimple steamturbines is poor.

2.4Steamturbinesthemainstayof BHEL

BHELhas thecapability todesign,manufacture and commission steamturbines ofup to 1000 MW rating forsteamparameters ranging from30 bars to 300 bars pressure and initial&reheat temperatures up to 600C.Turbinesarebuiltonthebuildingblock system, consistingof modulessuitable fora rangeofoutputand steamparameters.

3.TYPESOF STEAMTURBINE3.1Impulse turbineThe principle oftheimpulse steam turbine consistsofa casingcontaining stationarysteamnozzles and a rotor with moving orrotating buckets.Thesteampassesthroughthestationarynozzlesandisdirectedathighvelocityagainst rotor buckets causing therotor to rotateat high speed.Thefollowingeventstakeplaceinthenozzles:1. Thesteampressuredecreases.2. Theenthalpyofthesteamdecreases.3Thesteamvelocityincreases.4.Thevolumeofthesteamincreases.5.Thereisaconversionofheatenergytokineticenergyastheheatenergyfromthe decrease in steamenthalpy is converted into kinetic energyby theincreased steam velocity.

Figure 3- Impulse turbine3.2Theimpulse principle

Ifsteamat high pressure is allowed to expand through stationarynozzles, the resultwillbe a drop in the steampressure and an increase in steam velocity.In fact, the steam willissue from the nozzleinthe form ofa high-speedjet.Ifthishigh steam is applied to a properly shaped turbineblade, it willchangein direction dueto theshapeoftheblade. Theeffect ofthis changein direction of thesteamflow willbeto producean impulseforce, on theblade causing itto move. Iftheblade is attached to the rotor ofa turbine, then therotorwillrevolve. Force applied to thebladeis developed by causingthe steamto changedirection offlow (Newtons 2ndLaw changeofmomentum). The change ofmomentum producesthe impulse force. The fact that the pressure does not drop across the moving blades is thedistinguishing feature oftheimpulseturbine. The pressure at the inlet to themoving blades is the same as the pressure at the outlet from the moving blades.3.3Reaction principle

Areaction turbinehas rows offixed blades alternating with rows ofmoving blades.Thesteamexpands firstin the stationaryorfixed blades where it gains some velocityas itdrops inpressure.Itthenentersthe moving bladeswhereitsdirectionofflow is changedthusproducing an impulseforce on themoving blades. In addition, however,the steamupon passingthrough the moving blades again expands and further drops in pressuregiving areaction force totheblades. This sequenceis repeatedasthe steampasses through additionalrows offixed and moving blades.3.4Impulse turbine staging

In order for the steamto giveup allits kinetic energy to themoving blades in an impulse turbine,itshouldleave the blades at zero absolute velocity. This condition will exist ifthebladevelocity is equalto onehalfofthesteamvelocity.Therefore,for good efficiency theblade velocity should beabout onehalfofsteamvelocity. In order to reducesteamvelocity and bladevelocity, thefollowing methodsmay beused:1. Pressure compounding.2. Velocity compounding.3. Pressure-velocity compounding.

Figure 4-Reaction turbine4. TURBINEPARTS4.1Turbine blades Cylindrical reaction blades for HP, IP and LP Turbines 3-DS blades,in initial stages ofHPandIPTurbine,to reduce secondary losses. Twistedbladewithintegral shroud, inlaststagesof HP, IP andinitial stagesofLPturbines, to reduce profile and Tipleakage losses Freestanding LPmoving blades Tip sections with supersonic design Fir-tree root Flame hardening ofthe leading edge Banana type hollow guide blade Taperedandforwardleaningforoptimizedmassflowdistribution Suction slits for moistureremoval4.2Turbine casing

Casingsor cylinders areofthehorizontal split type. This is not ideal,astheheavyflangesofthejointsareslowtofollowthetemperaturechangesofthecylinderwalls.However,for assembling and inspection purposes there is no other solution. Thecasing is heavy in order to withstand thehigh pressures and temperatures. It is generalpractice to let the thickness ofwalls and flanges decrease frominlet-to exhaust-end.Thecasingjointsaremadesteamtight, withouttheuseof gaskets, bymatching theflange faces very exactly and very smoothly. Thebolt holes in theflanges are drilled forsmoothly fitting bolts,but dowel pins are oftenadded to secure exact alignment ofthe flangejoint. Double casings are used for very high steampressures. Thehigh pressureis appliedto the inner casing, which is open at the exhaustend,letting theturbineexhaust to the outer casings.4.3Turbine rotors

Thedesignof aturbinerotor dependsontheoperatingprincipleof theturbine. The impulseturbinewith pressure drop across the stationaryblades must have seals between stationaryblades and therotor. Thesmaller thesealing area, thesmaller theleakage; therefore the stationary blades aremounted in diaphragms with labyrinth seals around the shaft.This construction requires adisc rotor. Basically there are two types ofrotor: DISC ROTORSAlllarger disc rotors are now machinedout of a solid forging ofnickelsteel; this should give the strongest rotor and a fully balanced rotor.It is rather expensive, as theweight of the final rotor is approximately 50% oftheinitial forging. Olderorsmaller disc rotors have shaftand discs made in separate pieces with the discs shrunkon the shaft.Thebore ofthe discs is made 0.1%smaller in diameter than the shaft.The discs are then heated untilthem easily areslid along theshaft and located in thecorrect position on theshaft and shaftkey. DRUM ROTORSThefirstreactionturbineshadsolidforgeddrumrotors.Theywerestrong, generally wellbalanced as they were machined over the totalsurface.With the increasing size of turbines the solid rotors got too heavy pieces. For good balance thedrum must be machined both outside and insideand thedrum must be open at one end. Thesecond part ofthe rotor is the drumend cover with shaft.5.BLADING MATERIALSAmong thedifferent materials typically used for blading are 403 stainless steel, 422 stainlesssteel,A-286, and Haynes Stellite Alloy Number 31 and titaniumalloy. The403 stainless steelis essentially the industrys standard blade materialand, on impulse steamturbines, it is probablyfound on over 90 percent of allthestages. It is used because of its high yield strength, endurance limit, ductility, toughness, erosion and corrosion resistance,and damping. It is used within a Brinellhardness range of 207 to 248 to maximize its damping and corrosion resistance. The422 stainlesssteelmaterialsis applied only on high temperature stages (between 700 and 900For371 and 482C),where its higheryield,endurance, creep and rupture strengths are needed.TheA-286material isanickel basedsuperalloythatisgenerallyusedinhotgas expanders with stagetemperatures between900and 1150F(482 and 621C). The HaynesStelliteAlloy Number 31 is a cobalt-based super alloy and is used on jet expanderswhen precision castblades are needed.The Haynes Stellite Number31 is used at stagetemperaturesbetween 900 and 1200F(482 and 649C).Another bladematerial is titanium. Its high strength, low density, and good erosion resistancemakeit a good candidate for high speed orlong-last stage blading.6. MANUFACTURING PROCESS6.1Introduction

Manufacturingprocessis that partoftheproduction processwhich is directly concerned with the changeofform or dimensions ofthe part being produced.It does not includethe transportation,handling orstorageofparts,as they are not directly concerned with thechangesinto the formor dimensions ofthe part produced.

6.2classification of manufacturing processes

For producing of products materials are needed. It is therefore important to know the characteristics ofthe available engineering materials. Raw materials used manufacturing ofproducts, tools,machines and equipments in factoriesorindustries are for providing commercial castings, called ingots. Such ingots arethen processed in rollingmillsto obtainmarketformofmaterial supply in formof bloom, billets, slabsand rods. All theseprocesses used in manufacturing concern for changing theingots into usableproducts may beclassified into six majorgroups as Primaryshaping processes Secondarymachining processes Metalforming processes Joiningprocesses Surface finishing processes and Processes effecting changein properties6.2.1Primaryshaping processes

Primary shaping processes are manufacturing of a product froman amorphous material.Some processes produces finish products or articles into its usualform whereas others do not, and require further working to finish component to the desiredshapeand size. The parts produced through these processes may ormay not require undergoing further operations. Someofthe important primaries shaping processes are:(1)Casting(2)Powder metallurgy(3)Plastictechnology(4)Gas cutting(5)Bending and(6)Forging.6.2.2Secondaryor machining processes

As large number ofcomponents require further processing after theprimary processes.These components are subjected to one ormore numberofmachining operations in machineshops, to obtain thedesired shapeand dimensionalaccuracy on flat and cylindrical jobs. Thus, the jobs undergoing these operations are the roughly finished productsreceivedthroughprimary shaping processes.Some ofthe common secondary ormachining processes are: Turning Threading Knurling Milling Drilling Boring Planning Shaping Slotting Sawing Broaching Hobbing Grinding Gear Cutting ThreadcuttingUnconventional machining processesnamelymachining with Numerical control (NC) machines tools orComputer Numerical Control (CNC) machinetool using ECM, LBM, AJM, USMsetups.7.BLOCK3LAY-OUTS 7.1 Classification of block 3Bay 1- Size- 36*378 metersBay 2- Size 36*400 meters Bay 3- Size - 24*402 metersBay 4- Size- 24*381 meters respectively BAY-1ISFURTHER DIVIDEDINTO THREE PARTS1. HMS - In this shop heavy machine work is done with the helpofdifferentNC&CNCmachines such as center lathes, vertical and horizontalboring &millingmachines. Asias largest vertical boringmachineis installed here and CNC horizontal boring milling machines from Skoda ofCzechoslovakia.2. Assembly Section (of hydro turbines) In this section assembly ofhydro turbines are done. Blades ofturbineare1stassemble onthe rotor&afteritthisrotoristransported tobalancing tunnel where thebalancing is done. After balancing the rotor,rotor &casings both internal&externalaretransportedto thecustomer. Total assembly ofturbineis done in the company which purchased it by B.H.E.L.3. OSBT(overspeed balancing tunnel)-In this section, rotors of alltype of turbines like LP(lowpressure),HP(high pressure)&IP(Intermediatepressure) rotors ofSteamturbine,rotors of Gas&Hydro turbinearebalanced .In alargetunnel, Vacuumof2torriscreatedwiththehelpofpumps &afterthatrotorisplacedon pedestaland rottedwith speed of2500-4500 rpm. After it in acomputer controlroomthe axisofrotationofrotorisseen with help ofcomputer&then balance therotorby inserting thesmallbalancing weight in the grooves cuton rotor.

FIG.4OVERSPEED AND VACCUMBALANCING TUNNELBAY2ISDIVIDED IN TO 2PARTS:1. HMS- Inthisshopseveralcomponentsofsteam turbine likeLP,HP&IP rotors,Internal &external casing are manufactured with thehelp of different operations carried out through different NC & CNC machines like grinding, drilling, vertical & horizontal milling and boring machines, center lathes, planer, Kopp milling machine.2. Assembly section- In this section assembly ofsteamturbines up to 1000 MWIs assembled. 1st moving blades are inserted in the grooves cut on circumferences of rotor, then rotor is balanced in balancing tunnel in bay-1.After is donein which guide blades are assembled insidetheinternal casing & thenrotor is fitted insidethis casing. After it this internal casing with rotor is insertedinto theexternal.BAY3ISDIVIDED INTO 3PARTS:1. Bearing sectionIn this section Journal bearings are manufacturedwhich are used in turbinesto overcome the vibration &rolling friction byproviding the proper lubrication.2.Turning sectionIn this section smalllathemachines, milling & boring machines, grinding machines & drilling machines areinstalled. Inthis section smalljobs are manufactured like rings, studs, disks etc.3. Governing sectionIn these section governors are manufactured. These governors areused in turbines for controlling thespeed of rotor withinthe certain limits. 1st allcomponents ofgovernoraremade by different operations then these allparts are treated in heat treatment shop forproviding the hardness. Then theseallcomponents are assembled into casing. There are more than1000components ofGovernor.BAY-4ISDIVIDEDINTO 3PARTS:1.TBM(turbineblademanufacturing) shop-In this shop solidblade ofboth steam&gas turbineare manufactured.SeveralCNC&NCmachines are installed heresuchasCopyingmachine, Grinding machine, Rhomboid milling machine, Duplex milling machine, T- root machine center, Horizontal tooling center,Vertical&horizontalboring machineetc. 2. Heat treatment shop-In these sections thereareseveral tests performed forchecking thehardness ofdifferent components. Tests performed are Sterilizing, Nit riding, DP test. Stress relieving- consists of heating the steel to a temperature below the critical range to relive the stresses resulting from cold working, shearing, or gas cutting. It is not intended to alter the microstructure or mechanical properties as does annealing and normalizing. Flame hardening is a surface hardening method that involves heating a metal with a high temperature flame, followed by quenching. It is used on medium carbon, mild or alloy steel or cast iron to produce a wear resistant surface. The result of the hardening is controlled by four factors- Design of the flame head Duration of the heating Target temperature of the head Composition of the metal being treatedGas nitriding It is a surface hardening process, where nitrogen is added to the surface of steel parts using dissociated NH3 as the source. Gas nitriding develops a very hard case in a component at relatively low temperature, without the need for quenching. It can be performed in a pit furnace. It is also called ammonia nitriding .When ammonia comes into contact with heated work piece it disassociates into nitrogen and hydrogen. The nitrogen then diffuses onto the surface of the material creating a nitride layer. Salt bath Nitriding Nitriding is a salt bath heat treatment process that diffuses nitrogen into the surface of a metal at the ferritic stage to create a case hardened surface. Cyanide salt is used in salt bath nitriding . Temperature- (550-570 c) Advantages- quick processing time (4-6 hrs.) Simple operation heats the salt and work pieces to temperature until the duration has transpired. Disadvantages- salts used are highly toxic.

Figure 5-steam turbine casing and rotors I assembly area

Figure 6-CNC rotor turning lathe8. BLADESHOP

Blade shop is an important shop of Block 3.Blades ofallthestages ofturbineare made in this shop only.They havea variety of center latheand CNCmachines to perform the completeoperation ofblades. Thedesigns ofthe blades are sent to theshop and the Respectivejob is distributed to the operators. Operators performtheir job in afixed interval of time.8.1Types of blades

Basically the design ofblades is classified according to the stages ofturbine.The size of LP TURBINE BLADES is generally greater than that of HP TURBINE BLADES .At thefirst T1, T2, T3 & T4 kindsofbladeswereused, thesewere2nd generation blades.Then it was replaced by TX,BDS (for HP TURBINE) &F shaped blades. Themost modern blades are F&Zshaped blades.

Figure 7- types of blades8.2Operationsperformed on blades Some of theimportant operations performedon blademanufacturing are:- Milling Blank Cutting Grinding of both the surfaces Cutting Root milling8.3Machining of bladesMachining ofbladesisdone with the helpofLathe &CNCmachines.Some ofthe machinesare:- Centre lathe machine Vertical Boringmachine Vertical Milling machine CNC lathe machine

Figure 8- Schematic diagram of a CNC machine8.4Newbladeshop

Anew blade shop is being in operation,mostly 500mw turbineblades are manufactured in this shop.This is ahighly hitechshop wherecomplete manufacturing ofblades is done using single advanced CNC machines. Complete blades are finished using modernized CNCmachines. Someofthemachines are:- Pama CNCramboring machine Wotumhorizontalmachinewith6 axis CNCcontrol CNC shaping machine10. CONCLUSIONThetraining was specified under theTurbineManufacturing Department. Working under the department, Icameto know about the basic grinding, scaling and machining processes which was shown on heavy to medium machines.Duty lathes were planted in the Same linewherethe specifiedwork was undertaken.