Industrial Training Report

INDUSTRIAL TRAINING REPORT

Prepared byShashank PathakKautilya Institute of Technology and Engineering, JaipurRoll no.-10EKTME058

Submitted to:-Mr. B.K. GargDean Mechanical DepartmentKautilya Institute of Technology & Engineering, Jaipur

Certificate

PREFACE

As per the syllabus of B.Tech Engineering prescribed by Rajasthan Technical University in Mechanical Engineering an industrial training for the duration of one month is must to be conducted by the students.The practical knowledge and classroom discussion are not sufficient for an engineering student. It is also important to have the practical knowledge in order to know various facts of engineering. Such has been the presentations and projects which enhanced our learning by adding on to our world of knowledge. And summer training is one of the ways to enhance our practical knowledge and skills. It was a life time experience for which I thank to all the staff members of National Engineering Industries Limited (N.B.C), my parents, faculty members, administration of the kautilya institute of technology & engineering which is affiliated to Rajasthan Technical University. In our case we underwent training at NATIONAL ENGINEERING INDUSTRIES LIMITED (N.B.C).The following information is a comprehensive analysis of the work-done by us made possible due to the joint efforts of co-operative staff of National Engineering Industries Limited (N.B.C), and respected our professor.

ACKNOWLDGEMENT

The accomplishment of such vast experience and knowledge through this industrial training would not have been possible without the sheer brilliant guidance of experienced personals of the industry who with their support and vast experienced who in one way or another contributed and extended their valuable assistance in the preparation and completion of this project specially the head of department Mr. V.K. Sharma.

Firstly I would like to thanks our director Er. C.K. Bafna for providing students a campus to learn and apply their practical knowledge into the field of technology with such distinction facility with all the and faculties who prepare the students for real world and to make them eligible for industry oriented programs.

I would also like to show my gratitude toward Mr. Onkar Bunkar (head of the mechanical department) for his positive and enthusiastic attitude towards the welfare of the students and encouraging me by answering my questions and giving prompt replies for my uncertainties in all the fields including education, social and engineering work.

I would also like to acknowledge our dean of the department Mr. B.K. Garg sir who provided us with the opportunity so that we could apply our knowledge of what we have theoretically and practically learned in to the industry through the industrial training program.

Most Importantly, I would like to thank the company N.I.E.L, Jaipur, for providing me such a wonderful opportunity to work on such an interesting summer training project. This training really helped me in increasing my knowledge as well as my potential in technical field.

Last but not the least I would like to thank my family and my dear friends for being a constant support in my life and encouraging me whenever I hit the lows in my life that helped me improve my work.

INDEX

CONTENTPAGE NO. Introduction6-10 Background on N.E.I.L6-7 Bearings8-11 Jaipur Plant12-13 Bearing Designation15

Research and Development16

Project at N.I.E.L17 Railway Bearing Heat Treatment Spherical Bearing18 Cylindrical Bearing20 C.T.R.B (Cartridge tapered roller bearing)21 Heat Treatment24 Machines 27 Production of different bearing parts30 Assembly Line33

Conclusion36

INTRODUCTION

1. BACKGROUND ON N.E.I.L

Jaipur is the capital city of the state of Rajasthan, and is also known by the name of pink city. It is the fastest growing city of the India which is not only witnessing the social, educational development but also emerging out to be the industrial hub for the rising market in Asia community. National engineering industries limited was established in 1946 by the industrialist Mr. B.M. Birla in Jaipur. The company was formerly known by the name of National Bearing Company Ltd. which was later changed into the present name in the year 1958, retaining its original trade mark NBC due to increasing activities and grant of industrial licenses for other vital industries and manufacturing. Thecompany commenced manufacturingin 1950 with an annual productionof 30,000 bearings in 19 sizes.

Over the past 60 years, NBC has grown to be the leading and fastest growing bearingsbrand in India and currently produces over100 million bearingsin more than a 1000 sizes every year. It has the capacity to develop bearings from 10 mm bore to 2000 mm outer diameter. The product range includes ball bearings, tapered roller bearings, and double row angular contact (DRAC) bearings, cylindrical and spherical roller bearings. The company has specially equipped facilities to manufacture axle boxes for railway applications; cartridge tapered roller bearings, large-diameter bearings for industrial applications and allied engineering products.

The production plant at Jaipur boasts of the world class manufacturing and process technology. NBC Bearings are widely used by 2 and 3 Wheelers, Cars, Trucks, Tractors, Electric Motors, Railway wagons, coaches & locomotives, Steel Mills, Heavy Engineering Plants, Bulldozers, Shovels, Tillers and Thermal Power Plants. The automotive and railway industries form the two largest client segments.NBC has emerged as aleading exporterof bearings from India and its current export foot-print comprises of over21 countriesacross5 continents.Leading customers from US, Germany, Brazil, Japan, and Australia etc. have entrusted NBC with their critical product requirements.NBC serves the Indian aftermarket through a countrywide network of500authorized partners.

It is the second-largest Original Equipment Manufacturer (OEM) bearings to all the leading companies of India and abroad. In addition, the company exports bearings to more than 21 countries including OEMs inEuropeandUSA.Being one of the largest exporters of bearings from India, around 50 percent of its exports are for railways.

N.E.I.L has been awarded the coveted 20120 Deming Application Prize by the Union of Japanese Scientist and Engineers (JUSE), Japan, for achieving distinctive performance improvement through the application of Total Quality Management (TQM). The Deming medal confirms that the quality management system is one of the best, globally. For the customers this means enjoying consistently superior products and assurance of highest quality for every NBC bearing they use.

Manufacturing facilityNBC has manufacturing facilities atJaipur(established in 1946),Newai(established in 1980) andManesar(established in 2006). A fourth plant, a green field project, atSavliin Gujarat will ship out its first bearing in November 2013, ramping up production capacity to 150 million bearings per year once it is fully operational.All NBC manufacturing facilities boast of world-class manufacturing and process technology. International technicalcollaborations on critical machines& equipment and complete automation by flex-link conveyor systems contribute to an advanced, precise and highly productive manufacturing environment. Efficient and optimum use of space and best practices in every function and process sharpen the professional setting.There is a stringent focus on accuracy, high productivity and reduced cycle time. Employingpoka-yoke the Japanese approach to mistake proofing entire processes ensures error free operations. NBC practices are based onKaizenand continuous improvement and the outcome is visible across the organization from the shop floor to the boardroom. All NBC plants are automated and systematic, sorted and kept clean, with standardized processes and sustained service. There is a place for everything and everything has its place.The Jaipur Facility has a brand-new state of the art R & D Centre that lies at the heart of the Excellence that NBC delivers. The Centre and its lab, considered among the best in Asia, fulfils a critical function in the innovative and superior quality of products that NBC produces and is aligned to the companys core values and vision.

BEARING

Abearingis amachine elementthat constrains relative motion betweenmoving partsto only the desired motion. The design of the bearing may, for example, provide for freelinearmovement of the moving part or for freerotation around a fixed axis; or, it maypreventa motion by controlling thevectors ofnormal forcesthat bear on the moving parts. Many bearings alsofacilitatethe desired motion as much as possible, such as by minimizing friction. Bearings are classified broadly according to the type of operation, the motions allowed, or to the directions of the loads (forces) applied to the parts.a. The bearing ensures free rotation of the shaft or the axle with minimum friction.b. The bearing supports the shaft or the axle and holds it in the correct position.c. The bearing takes up the forces that act on the shaft or the axle and transmits them to the frame or the foundation. Bearings are generally of two types1. Rolling contact bearing2. Sliding contact bearingThese further can be sub catagerosied into different types.1. Roller contact bearing

Roller contact bearing are also called antifriction bearings or simply ball bearings. Rolling elements such as balls or rollers are introduced between the surfaces that are in relative motion. In this type of bearing sliding friction is replaced by the rolling friction. For starting condition and at moderate speeds, the frictional losses in rolling contact bearing are lower than that most of equivalent hydrodynamic journal bearing. This is because the sliding contact is replaced by rolling contact resulting in low coefficient of friction. Therefore rolling contact bearing is called, antifriction bearing. However this is a misnomer. There is always a friction at the contacting surfaces between the rolling element and inner and outer cages.

Types of roller contact bearing

Deep groove Cylindrical roller Angular contact Self-aligning Spherical roller Taper roller Thrust ball bearingApplications Machine tool spindles Automobile front and rear axles Gear boxes Small size electric motors Rope sheaves, crane hooks and hoisting drums

2. Sliding contact bearingSliding contact bearings are also called plain bearings, journal bearings or sleeve bearings. In this case the surface of the shaft slides over the surface of the bush resulting in friction and wear.in order to reduce the friction, these two surfaces are separated by a film of lubricating oil. The bush is made of special material like white metal or bronze.Sliding contact bearings are classified in three ways. 1. Based on type of load carried 2. Based on type of lubrication 3. Based on lubrication mechanism

Bearing classification based on type of load carried Radial bearings Thrust bearings or axial bearings Radial thrust bearings

Bearing classification based on type of lubricationThe type of lubrication means the extent to which the contacting surfaces are separated in a shaft bearing combination. This classification includes Thick film lubrication Thin film lubrication Boundary lubrication

Bearing classification based on lubrication mechanism Hydrodynamic lubricated bearings Hydrostatic lubricated bearings Elastohydrodynamic lubricated bearings Boundary lubricated bearings Solid film lubricated bearings

Application Crankshaft bearings in diesel and petrol engine Centrifugal pumps Large size electric motor Steam and gas turbines Concrete mixers, rope conveyors and marine installations

BRIEF TABLE OF DIFFERENT TYPE OF BEARINGS

NameApplication

Single Row Radial Ball Bearing1. In addition to Radial Loads, Axial Loads can be imposed in either direction.2. Highly Suitable for applications where High Speed & LowPowerloss are required.

Single Row AngularContact Ball Bearing1. They are capable of takingRadial Load& alsothe Axial Load in one direction.2. 4 contact angles 15, 25, 30 &40 are available. Higher the contact angle higher is the Axial Loadcarrying capacity.3. For Higher Speed lower contact angles arepreferred.

Double Row AngularContact Ball Bearing1. They are 2 single RowAngular ContactBall Bearing mounted back toback.2. They have only one inner and one outer ring.3. They can take axial load in either direction

Self-Aligning Ball Bearing1. The Inner Ring has 2Raceways &Outer Ringhas a singleSpherical Raceway with its centre of curvature coincident with bearing axis.2. This has an advantage of correcting minor angular misalignment ofShaft and Housing caused byMachining or Mounting Error

Cylindrical RollerBearing1. They have High Radial Load capacity and are suitable for High Speed.2. Double Row bearing have high Radial Rigidity and are used primarily forhigh Precision Instruments.

Tapered Roller Bearing1. They are capable of takinghigh Radial Loads& alsoAxial Load in one Direction.2. Depending upon the contact angle theyare divided into 3 types,Normal,Medium & SteepAngle

Spherical RollerBearing1. Due to coincide of the centre of curvature of the outer ring raceway surface with the bearing axis, they arealso called as Self Aligning Bearing.2. They can take Heavy Radial Load & some Axial Load in eitherdirection.3. They are suitable for theuse where there is Heavy or Impact Load.

Thrust Bearing1. They are capable of takingHigh Axial Load and some amountof Radial Load.2. Outer & Inner Rings are called as Washer because they seem tobe as Washer in Structure.

JAIPUR PLANTThere are generally four main types of bearing manufactured at the Jaipur plant which are mentioned as following:-

1. Ball bearing2. Steel ball3. Tapered roller bearing 4. Railway bearing5. Very large diameter bearing

1. Ball bearing

Precision Ball Bearings from 6 mm bore to 75 mm bore diameter are manufactured on state of the art manufacturing facilities with in-process and post-process gauging in grinding and centrally air conditioned assembly lines with auto gauging and testing equipment. The latest advanced techniques for manufacturing and Quality Assurance are implemented to meet the rapid increase in demand for Quality, diversity of specifications and new types of bearings.This Division is spread over a covered area of 14,694 Sq. Meters.

2. Steel ball

Precision Steel Balls up to 25 mm diameters for NBC Bearings are manufactured on precision grinding and lapping machines to achieve super finished surface, accuracy and roundness as per ISO standards.This Division is spread over a covered area of 4,700 Sq. Meters

3. Tapered roller bearing

Precision Tapered Roller Bearings are manufactured in Inch and Metric series from 15.875mm bore to 95.25mm bore with technology obtained from our earlier collaborator, Federal Mogul Corporation, USA and now with NTN Corporation, Japan. These bearings are used by all major Automobile manufacturers in the country as Original Equipment.This Division is spread over a covered area of 11,652 Sq. Meters.

4. Railway bearing

Roller Bearing in Axle Box:

With the production of Roller Bearings and Axle Boxes since 1952, the company has fully met the requirements of the Indian Railways (one of the largest systems of the world) by designing and developing Axle Boxes and bearings for fitment to Locomotives manufactured by Diesel Locomotive Works , Chittaranjan Locomotive Works, various wagon builders, the ICF broad and meter gauge coaches. Over a million NBC bearings and boxes are in service with the Indian Railways. The development of completely indigenized Axle Boxes and bearings for the high speed Rajdhani Locomotive,the Yugoslavian and Egyptian Railway wagons are the highlights of the design capabilities at NEI.On date more than 100 types of Axle Boxes & Bearings have been manufactured.

Spherical Roller Bearing:

The manufacturing of Spherical Roller Bearings was started in the year 1975-76 for fitment to broad gauge and meter gauge passenger coaches with designs, technology, machines and equipment procured from the collaborators.

Cartridge Tapered Roller Bearing:

For fitment to the new BOX-IN Up rated Wagons designed by the RDSO, NEI is the only manufacturer in the country to indigenize these bearings to a high percentage under collaboration with the largest manufacturer ofthese bearings in the world. Production of these bearings commenced in the year1984. These bearings are grease packed and require no field lubrication for a period of 7 years.This Division is spread over a covered area of 4,855 Sq. Meters.

Very large diameter bearing

Self-sufficiency in steel is the call of the day, so is the importance of bearings in Steel Mills Equipment. NEI has the distinction of being one of the ten manufacturers of these bearings in the world, who can manufacture large diameter bearings up to 2000 mm diameter.The largest bearing manufactured by NEI for fitment to the Plate Mill of Rourkela Steel Plant was released by Mr. G.P. Birla in September 1985. This 4-Row Tapered Roller Bearing measures 1300 mm diameter and weigh 4.39 tons.

The large diameter bearings are mainly manufactured out of case carburizing steel, heat treated on special equipment and furnaces developed by NEI. Precision grinding is done to close tolerances on CNC Twin Spindle Programmable Berthiez Machine for bearings ranging from 500 to 2000 mm diameter with electronic sizing and numerical display.Production of these bearings started in 1975 and to date over 100 different types of special large diameter bearings have been manufactured and successfully used, saving considerable foreign exchange for the country.The Large Diameter Bearings Division is spread over a covered area of 2,508 Sq. Meters.

BEARING DESIGNATION

Rolling bearing part numbers indicate bearing type, dimension, tolerances, internal construction and other related specifications. The first letter (digit) indicates the bearing type. The second digit indicates width (or height) series and the the third indicates the diameter series. The last two digits indicate the bore diameter by multiplying the last two digits by five for bearing having bore diameter original 40 mm and above. This method is applicable for metric series bearing only.Example.

RESEARCH & DEVELOPMENT

Design & DevelopmentThe design of all types of bearings is done on Pro-Engineer 3D Modelling & AnalysisSoftware.Completeengineering andresearchwith in-house facility fordesign development ofall types of bearings and tooling with expert advice on design, development, manufacturing, installation and maintenance of bearings facility is available. With the signing of the technical collaboration agreement with NTN Corporation, Japan & BRENCO Inc. ofUSA, the capability to offer finest engineering services in the bearing industry has enhanced. Services of team of experienced engineers are available for selection ofbearing as per application.

Machine BuildingNEIhasthecapabilityofmachinebuildingtodesign,developandmanufacturespecialpurposeCNCGrindingLines,HTLines,MaterialHandlingEquipmentsandotherspecial purpose machines which have been made for its captive use to keep pace with latest technology. A well-equipped electronic design, development laboratory with all testing facilities supports the Machine Building Division.MachineBuildinghasthecapabilityandsupportstheManufacturingDivisionsbyoverhauling and retrofitting of the existing equipments, resulting in upgraded quality and improved productivity.R&D Division is spread over a covered area of 2,007 Sq. Meters.

SAP ERPInordertoreengineerandintegratetheBusinessprocessesforsales,production, materials and finance, NEI has successfully implemented SAP- ERP. By use of this Package, their processes now conform to international standard

PROJECT AT NEILRAILWAY BEARING AND HEAT TREATMENT DEPARTMENTThe project assigned to mechanical students was in the department of railway bearing and heat treatment, where the bearing for the railways were manufactured through heat treatment process. As mentioned above there are four types of bearing manufactured and processed in this department. Spherical Cylindrical CTRB (cartridge tapered roller bearing)The department dealt with bearings required for the railway and the heat treatment of the bearings and their rings. This Division is spread over a covered area of 4,855 Sq. Meters.ROLLER BEARING IN AXLE BOXWith the production of Roller Bearings and Axle Boxes since 1952, the company has fully met the requirements of the Indian Railways (one of the largest systems of the world) by designing and developing Axle Boxes and bearings for fitment to Locomotives manufactured by Diesel Locomotive Works , Chittaranjan Locomotive Works, various wagon builders, the ICF broad and meter gauge coaches.Over a million NBC bearings and boxes are in service with the Indian Railways. The development of completely indigenised Axle Boxes and bearings for the high speed Rajdhani Locomotive, the Yugoslavian and Egyptian Railway wagons are the highlights of the design capabilities at NEI. On date more than 100 types of Axle Boxes & Bearings have been manufactured.SPHERICAL ROLLER BEARINGSThe manufacturing of Spherical Roller Bearings was started in the year 1975-76 for fitment to broad gauge and meter gauge passenger coaches with designs, technology, machines and equipment procured from the collaborators.CARTRIDGE TAPERED ROLLER BEARINGSFor fitment to the new BOX-IN Uprated Wagons designed by the RDSO, NEI is the only manufacturer in the country to indigenise these bearings to a high percentage under collaboration with the largest manufacturer of these bearings in the world. Production of these bearings commenced in the year 1984. These bearings are grease packed and require no field lubrication for a period of 7 years.

LARGE DIAMETER BEARINGSThe Large Diameter Bearings Division is spread over a covered area of 2,508 Sq. Meters.Self-sufficiency in steel is the call of the day, so is the importance of bearings in Steel Mills Equipment. NEI has the distinction of being one of the ten manufacturers of these bearings in the world, who can manufacture large diameter bearings up to 2000 mm diameter. The largest bearing manufactured by NEI for fitment to the Plate Mill of Rourkela Steel Plant was released in September 1985. This 4-Row Tapered Roller Bearing measures 1300mm dia and weigh 4.39 tons.The large diameter bearings are mainly manufactured out of case carburising steel, heat treated on special equipment and furnaces developed by NEI. Precision grinding is done to close tolerances on CNC Twin Spindle Programmable Berthiez Machine for bearings ranging from 500 to 2000 mm diameter with electronic sizing and numerical display.

1. SPHERICAL BEARINGS

Aspherical bearingis abearingthat permits angular rotation about a central point in two orthogonal directions (usually within a specified angular limit based on the bearing geometry). Typically these bearings support a rotating shaft in the [bore] of the inner ring that must move not only rotationally, but also at an angle.

Nbc spherical roller bearingApplication in Indian railwaysAxle load

22320 C/C3M.G. Passenger Coach10.25t

22326 C/C3B.G. Pasaanager Coach16.25t

22328 BL1C3B.G, E.M.U20.0t

Meanings of suffix/prefixC = Type C Roller (Symmetrical) C3 = Radial internal clearance C3 B = Type B Roller (Asymmetrical)L1= High Strength machined brass cageOuter ringOuter ring for NBC spherical roller bearings are manufactured from forged and rolled rings from bearing quality steel. It is through hardened and precision ground all over. The track or roller surface of bearing outer ring is spherical in shape for self-aligning.Inner RingInner ring for NBC spherical roller bearing are also made from bearing quality steel which is forged and rolled. Inner rings are also precision machined heat-treated and precision ground. Inner ring have two rolling surface which are ground together with high accuracy.

RollerRoller are either forged or machined from bearing quality steel bars & then through hardened and ground to high degree of accuracies. In bearing 22320 and 22326, symmetrical design rollers are used and for bearing 22328, asymmetrical design rollers are used.

CageNBC spherical roller bearings are fitted with machined brass cages. These cages are made from brass centrifugal castings and then precision machined. Brass cages have advantage of assuring positive lubrication and cooler running of the bearing therefore are best recommended for railway applications.

CYLINDRICAL BEARING

The cylindrical roller bearings have greater radial load capacity than ball bearings of same external dimensions and are particularly suitable for arduous duties.The bearing features a modified line contact between rollers and raceways to eliminate edge stressing.These bearings have a high radial load capacity and are suitable for high speeds. Due to detachable design character they have advantage of mounting inner ring and outer ring separately.The direction of axial load which a bearing can take depending upon the geometry of the bearing. Many variations available are shown below :

CTRB (CARTRIDGE TAPERED ROLLER BEARING)

Tapered roller bearing are designed in such a way that vertices of the cone for each roller and those for the inner and outer raceways coincides on the bearing axis or extensions of the raceways and rollers converge at a common point on the axis of rotation. This results in true rolling motion of the rollers on the raceways at every point along the rollers.The tapered roller bearing supports radial loads and axial loads from one direction only. The line contact between rollers and raceway provide the bearings with a high load carrying capacity. Steep angle tapered roller bearing with exceptionally steep cone angle enables the bearings to take heavier load.The bearings are of separable type, enabling separate mounting of cups and cones. Since the tapered roller bearings can absorb thrusts loads in one direction only, these bearings should generally be installed as opposed mountings. The correct amount of radial and axial clearance is obtained by adjusting the two bearings against each other.Besides, double row and four row tapered roller bearings are also widely used for heavy loads such as rolling mills.The inner and outer raceways are segments of cones and the rollers are also made with a taper so that the conical surfaces of the raceways and the roller axes if projected, would all meet a common point on the main axis of the bearing. This conical geometry is used as it gives a larger contact patch, which permits greater loads to be carried than with the spherical bearings, while the geometry means that the tangential speeds of the surfaces of each of the rollers are the same as their raceways along the whole length of the contact patch and no differential scrubbing occurs. When a roller slides rather than rolls, it can generate wear at the roller to race degenerate the close tolerances normally held in the bearing and can lead to other problems. Much closer to pure rolling can be achieved in a tapered roller bearing and this avoids rapid wear.The rollers are guided by a flange on the inner ring. This stops the rollers from sliding out at the high speed due to their momentum.The larger the half angles of those cones the larger the axial force that the bearing can sustain.Tapered roller bearings are separable and have the following components: outer ring, inner ring, and roller assembly (containing the rollers and a cage). The non-separable inner ring and roller assembly is called the cone, and the outer ring is called the cup. Internal clearance is established during mounting by the axial position of the cone relative to the cup.RAW MATERIAL:The Races & Rolling elements of Bearing are subjected to stress on a very small contact surface must be of such material also as to with stand wear and have high elastic Limit & fatigue Limit. The raw material being used by the Industry forManufacturing of various Bearing components are as under:CUP AND CONE:The raw material used in the Manufacturing of bearing Races is SAE 52100 high Carbon Chrome bearing steel, which has composition similar to EN-31 (100 CR 6 Asper BIS specification). The raw material for Bearing Races is in the form of Rods &Seamless Hollow Tubes. This is a Spheroids Annealed Steel. Approx. 80% of the Seamless Hollow tubes are purchased by the Industry from M/s. Indian Seamless Metal tube PUNE, while the rest of the tube used in the cluster is imported material. The Steel bar are purchased from M/s. Indian Seamless Steel & Alloy Pune & M/s.Mahindra Ugine Steel Company KHAPOLI (Maharashtra).Some of the units are buying the steel scrap rod for manufacturing bearing races. Bearing Races material and their heat treatment are required to be selected carefully, taking account the mechanical strength and required life of the Bearing,Approximate required composition forbearing races are Constitute % CompositionCarbon0.95to1.1Chromium1.4to1.6Manganese0.50max.Silicon0.15to0.35Sulphur0.025(Max.)Phosphorous 0.05CAGE'S:Cage is used to return balls at proper distance to prevent them from containing each other and to prevent a temperature rise and resultant damage due to friction. The Material for manufacturing cages is CRCA Strips of C2015 Bearing grade steel having carbon percentage at0.08% max. And Magnesium ranging from 0.25% to 0.45%

HEAT TREATMENT

The heat treatment process for all the four bearings is almost same. With only few differences here and there. The general process of heat treatment is shown in the following diagram. Heat treatment process is the process of hardening the soft material. The row materials soft material and it has to be hardened before grinding, and hardening increase the life of bearing. Hardening is done in a special furnace named CHUGAIROfurnace. The soft machined material is feed in the furnace and washed at 600C, then send to a chamber where the material heated in four chambers the first chamber has the temperature 840c and further chamber contains the 850c temperature. Then it is dipped into an oil tank at temperature 25c where the material get quenched then it is washed and then it is tempered in water for about 90 min. at temperature 105c after that dried and cooled in air, the hardened material is obtained.

Some salient features of heat treatment in R.B.H.T There are three different manually operated heat treatment process units are available for the three bearing i.e. spherical, cylindrical and cartridge. And one specially automated robotic hate treatment unit is installed in the Railway Bearing Heat Treatment department for the Cartridge Tapered Railway Bearing. A plant for the production of heating agent which is gas there is also installed in the facility. the gas used is the endo gas and L.P.G gas. Other than heat treatment of various bearings, C.T.R.B cups and wear rings are also made to go through the heat treatment process and the plant. The oil used in the quenching process of CTRB rings and cups is generally Betaquinine U3. The general purpose of using oil is for the protection and heating maintenance of the material. The salt is used in the heating process of the spherical and cylindrical bearings, the general purpose of the salt is to prevent scaling and a bit of carbonising. V-belt is used in the tempering process machine in the heat treatment process of CTRB cups in chugairo furnace.

A simple diagram showing the heat treatment plant.Expected tangible benefits- heat treatment

Production/hourRejection-%

Hardness-HRC

MACHINESThe various machines used in the heat treatment of these bearings and wear rings and cups are mentioned as follows:-1. R.H.F2. U.B.H3. Salt bath furnace4. Automatic cup machine

1. R.H.F (Rotary Hearth Furnace)

This robust furnace type is extremely versatile in its use. It is designed for both carburizing shallow case depths and for reheating pre-treated work pieces. Its high throughput makes it particularly suitable for heat treating large quantities of the same parts.The rotary hearth furnace can be operated as a stand-alone unit with either manual or automatic loading/unloading, and also be interlinked with other plant components.The benefits of this furnace type include: High throughput with even temperature distribution Robotic loading for automated press quenching systems Hardening applications for a wide range of products Special tray and door design for maximum performance

2. U.B.H (Universal Batch Hardening)

Intensive quenching is a very rapid and uniform cooling of steel parts that causes the simultaneous formation of martensite throughout the whole part surface, creating a firm shell. The strong martensite case or shell minimizes part distortion.Metallurgical processes includeneutral hardening, carburizing, carbonitriding, normalizing, and annealing. The UBIQ furnace is suitable for drive and axle components, transmission components, shafts, fasteners, bearing components, and precision machined components. Capacity ranges from 1100 to 6000 lb., in sizes up to 6 ft. Normal operating temperature is 1450 to 1750F, with a maximum of 2000F, and excellent temperature uniformity.

3. Salt Bath Furnace

In metal quenching, a part is cooled from the austenitizing temperature fast enough to avoid the pearlite nose of the materials time-temperature-transformation (TTT) diagram and to transform the austenite into martensite to the maximum extent possible. When the quenching medium is water, brine, a polymer solution, or fast oil, it is generally referred to as conventional quenching. Steels with low hardenability can be quenched this way. However, this method can cause distortion and in some cases, nonuniform hardness or even cracking. The tendency to distort increases with increasing steel hardenability.Causes of distortion usually can be traced to uneven or nonuniform quenching, thermal stresses, and transformational stresses. These factors often can be mitigated by adopting an interrupted quenching technique.In interrupted quenching, parts are cooled rapidly from the austeitizing temperature to a point above the martensite start temperature (Ms), where they are held for a specified time and then cooled to room temperature. Thermal stresses and the potential for distortion are considerably reduced during the hold above Ms. Processes that make use of an interrupted quench include martempering, austempering and variations of them.For most steel and alloys, the temperature at which the quench is interrupted is usually in the 175 to 370C (350 to 700F) range. Water, brine, polymer solutions and most quench oils cannot be used at these temperatures. Attempts at using molten lead and fluidized beds do not appear to have met with much success. Some oils can be used at temperatures up to 230C (450F), but for higher temperatures, molten salt is the natural, practical choice.

PRODUCTION OF BEARING PARTS

1. Production of inner/outer race

Inner and outer tracks are produced in the same way except for the contours being different and the surfaces being ground. Raw material taken as forged rings of the starting material are turned and sent for heat treatment. After heat treatment tooling cannot be done because of the hardness attained by the material. Further machining done is in the form of grinding. Rough grinding is done on the races. Rough grinding consists of face grinding and Outside Diameter Grinding for the races. Finish grinding is done on the production line where the raceways are ground. These are the grooves in which the balls move, therefore require greater accuracy. After finish grinding honing and super finishing is done using honing stones to obtain a mirror smooth finish on the tracks.

2. Production of balls

Production of balls is much difficult as compared to the races. This is due to the fact that the balls can be out of round only to an allowable value of 25 microns even for the most inexpensive bearings. Balls are made out of wire rods. Required length of wire is sheared off and pressed between the dies of the ball header which gives us balls with a ring of flash around them, similar in appearance to the planet Saturn. This flash is removed by making the balls rotate in concentric channels of two roughing wheels. After this process the balls are sent for hardening and ground to a size little larger than the required size. Rest of the process of lapping is done in a similar way as roughing and grinding except for the fact that the wheel used is of cast iron and abrasive slurry is also used.

3. Cage production

Cages are made out of thin strips of cold rolled steel. Annular rings are blanked out of the steel strip and formed in between dies to form the pockets for accommodating the balls. Rivet holes are pierced which hold the rivets which are used to fasten the two halves of the cages together in case of metallic cages. Finally the surfaces are smoothened out for reduction in friction and cleaning is done before the cages are sent for assembly. In case of plastic cages, the material used varies according to the requirements of the bearings. These cages are made by injection moulding processes and do not require riveting to hold the cages together. The cages need not be made in two halves. Only one moulding of the cage can be snapped onto the balls to help faster assembly.

ASSEMBLY OF BEARINGS1. BALL BEARING ASSMBLE LINE

2. Roller bearing assembly line

CONCLUSION

I hereby conclude my report on industrial training where I had the pleasure of acquainting myself with the knowledge and practical aspects of theory of bearings that I learned in my engineering. The training provided me with the skills and aspects of how work is done in industries and helped me with my experience in industrial skills. I am thankful to the National Engineering Industries Ltd. (N.B.C) management to permit for the training in their Jaipur based industry and have helped me to enhance my knowledge of Mechanical Engineering in an industry.

SHASHANK PATHAK10EKTME058MECHANICAL Page | 1