nbc training report on railway bearing(spherical bearing)

REPORT ON NBC, JAIPUR 2014-2015

A

REPORT ON SUMMER TRAINING

Taken At

NBC, JAIPUR

(From --------------to-------------)

Submitted in partial fulfillment of the requirements For the award of the

DiplomaIn

Mechanical Engineering

APEX POLYTECHNIC INSTITUTE, JAIPUR

(SESSION: 2014-15)

SUBMITTED TO: SUBMITTED BY:

Mr. Hitesh Mariwala Ashutosh Singh H.O.D. IInd Year 13APIME050

DEPARTMENT OF MECHANICAL ENGG.

APEX POLYTECHNIC INSTITUTE DIPLOMA, MECHANICAL ENGG.


PREFACE

As per the requirement of Diploma Course, National Engineering Industries Ltd.

(NEI), Jaipur has been kind enough to permit me to complete my Practical Training

under railway bearing division.

This report prepared during the practical training which is student’s first and greatest

treasure as it is full of experience, observation and knowledge.

The industrial training was very interesting and gainful as it is close to real what have

been studied is all the years through was seen implemented in a modified and

practical form.

The student wishes that this Gorgeous Private Sector undertaking success so that it

may flourish and serve the nation which has reached significant years of its

independence and has to achieve many goals.

ASHUTOSH SINGH

13APIME050



ACKNOWLEDGEMENT

Words fail me to express my sincerest gratitude to this esteemed organization, which

has conferred on us the privilege to pragmatically convert our theoretical knowledge

into practical experience. During the course of my training at NATIONAL

ENGINEERING INDUSTRIES LIMITED, JAIPUR so many people have guided me

and I will remain indebted to them throughout my life for making my training at

NBC, a wonderful learning experience.

I would like to thank MR. ANKIT AGARWAL (LECTURER) which under

completed this training report file, Mr. HITESH MARIWALA (HOD), who gave

me opportunity to work in this department and guided me through my report from

time to time. His words were a true inspiration for me. The exposure to the working of

the industry that I have got here would not have been possible without his kind

support.

He took keen interest in my report and ensured that my tenure at NBC, JAIPUR is a

learning experience for a lifetime for me.

Thanks to all those operators, Diploma Engineer Trainees and my trainee colleagues

with whom I had developed a special bond. In the end I would like to thank Mr. A.

THOMAS for providing me the opportunity to add a new dimension in my

knowledge by getting trained in this esteemed organization.

DATE: 11/02/2016 ANKIT AGARWAL ASHUTOSH SINGH

(LECTURER) 13APIME050

GUIDED



ABSTRACT

The following report gives a brief explanation of the Industrial Training attended at

NBC, Jaipur. The report gives a detailed explanation of the training program and how

it is an essential part in professional learning. The report also give an insight in the

working of the NBC, the Technologies used and the Quality processes implemented

and habituated. It gives a clear cut idea about how the product is bought into existence

from raw material to the finished good. A transparent idea of working of a

Manufacturing Industry can be understood by the report.

ASHUTOSH SINGH

13APIME050



TABLE OF CONTENTS

Acknowledgement ……………………………………………………………………ii

Abstract …………………………………………………..………………………..iii

List of tables………………………………………………………………………vi

List of figures …………………………..………………………………………..vii

Chapter 1: Introduction …………………..……………………………………….1

1.1 Company profile …………………….………………………………………..11.2 Milestones ……………………...…………………………………...………21.3 Technical Collaboration ……………………..…………………….……….31.4 Main Customers …………………………………………...……………...…31.5 Manufacturing facilities ……………………………………….…………….4

Chapter 2: NBC Jaipur ……….……………………...............................................6

2.1 Introduction………………………………….…………..……………...……62.2 Ball bearing…………………………………………………….....………....72.3 Precision ball bearing………………………………………………..……....82.4 Tapered roller bearing…………………………………………………….....82.5 Railway bearing………………………………………………….…….…....92.6 Large diameter bearing………………………………………………............112.7 Research and development………………………………………………112.8 SAP-ERP………………………………………………………….……..…...12

Chapter 3: Railway bearing division….……….…………………………………..13

3.1 Introduction…………………………………………..…………………….133.2 Spherical roller bearing……………………………………………..………..133.3 Bearing materials……………………………………………………………..143.4 Raw material suppliers……………………………………………………..16

Chapter 4: Material used in bearing………………………………………..……....18

4.1 Bearing material…………………………………………………………….184.2 Flow of material in bearing…………………………………………………19

Chapter 5: Process of manufacturing ……………………………………..………..20

5.1 Manufacturing process of tapered roller bearing …………………………..205.2 Heat treatment and laboratory ………………………………………...…215.3 Carburizing ……………………………………………………………..….225.4 Hardening furnace ……………………………………………………........235.5 Quencing……………………………………………………………...…….235.6 Tampering………………………………………….…………………….24



5.7 Rockwell hardness test……………………………………………………..245.8 Grinding section…………………………………………………….………265.9 Assembly section……………………………………………...……………305.10 Maintenance and inspection section………………………………………..31

Chapter 6: Manufacturing & Assembly ………...………………………………….33

6.1 Inner & outer ring manufacturing ……...…………………………………..336.2 Roller manufacturing ………………………………………………………356.3 Cage manufacturing ……………….……………………………………….366.4 Roller bearing assembly line ……………………………………………….37

Chapter 7: Application …...…………………………………………………...……38

Chapter 8: Conclusion .............................................................................…………...39

Bibliography………………………………………………………………………..40

References…………………………………………………………………………..41



LIST OF TABLES

S. NO. NAME OF TABLES PAGE NO.

3.1 Contents Of Impurities In a Raw Material 153.2 Materials Of Different Components Of a Bearing 16



LIST OF FIGURES

S. NO. NAME OF FIGURES PAGE NO.

1.1 Milestones 21.2 Manaser Plant 52.1 Jaipur Plant 62.2 NBC Design And Development 62.3 Ball Bearing 72.4 Steel Ball 82.5 Tapered Roller Bearing 92.6 Axel Boxes 102.7 Railway Bearing 103.1 Spherical Roller Bearing 144.1 Flow Of Material In Bearing 195.1 Manufacturing Process Of Spherical Roller Bearing 205.2 Heat Treatment Sequence 215.3 Flow Diagram Of Heating Sequence Of Spherical

Bearing22

5.4 Rotary Hearth Furnace 235.5 Tempering Furnace 245.6 Rockwell Hardness Test Setup 255.7 Process Sequence 265.8 Process Sequences For Outer Race Grinding 285.9 Face Grinding 285.10 Rollers Of Spherical Bearing 295.11 Process Sequence For Grinding Of Rollers 295.12 Face Grinding Of Roller 295.13 Body Grinding Of Rollers 305.14 Roller Super Finishing 305.15 Element After Assembly Of Spherical Bearing 316.1 Flow Chart Of Inner And Outer Ring Manufacturing 336.2 Manufacturing Of Roller 356.3 Cage Manufacturing 366.4 Roller Bearing Assembly Line 37



CHAPTER-1

INTRODUCTION

1.1. Company profileThe renowned industrialist, late Shree B. M. Birla founded National Engineering

Industries Ltd., Jaipur in the year 1946 as a pioneer industry in the field of bearing

manufacture, under the name of "National Bearing Company Ltd."

The first bearing was manufactured in 1950 with a modest start of 30,000 bearings in

19 sizes. The company is now manufacturing nearly 3.8 million bearings per month in

over 500 different sizes ranging from 6 mm bore to 1300 mm outer diameter and has

the capacity to manufacture bearings upto 2000 mm outer diameter. At NEI, the

development of bearings is a never ending job. With ever increasing activities and

grant of industrial licenses for other vital industries and manufacturing of Roller

Bearing Axle Boxes for Railway Rolling Stock, Steel Balls, Tapered Roller Bearings,

Spindle Inserts etc., the name of the company was changed in 1958 to "National

Engineering Industries Ltd." retaining its original trade mark NBC.

The industry is spread over 118 acres of land in Jaipur and 56 acres in Gunsi (Newai).

This is the only unit in the country manufacturing wide variety and range of bearings

such as Ball Bearings, Steel Balls, Tapered Roller Bearings, Cylindrical Roller

Bearings & Axle Boxes for Railway Rolling Stock including Spherical Roller

Bearings, Cartridge Tapered Roller Bearings and Large Diameter special Bearings in

separate fully equipped factories. The development of National Engineering Industries

Ltd., was pioneered with a theme “Indigenization and Self-reliance".

NBC Bearings are widely used by 2 and 3 Wheelers, Cars, Trucks, Tractors, Electric

Motors, Railway wagon, Coach and Locomotive manufacturers as Original

Equipment and Steel Mills, Heavy Engineering Plants, Bulldozers, Shovels, Tillers

and Thermal Power Plants all across the country.



1.2. Milestones

Fig.1.1: Milestones of NEI

i. 1946 -Company established as National Bearing Company (NBC) under

technical collaboration with Hoffman, U.K.

ii. 1950 Ball Bearing Production started.

iii. 1958 Company is renamed National Engineering Industries Limited (NEI);

NBC Trademark retained.

iv. 1967 Tapered Roller Bearing production started

v. 1975 Spherical Roller Bearings production begins

vi. 1981 Second Plant inaugurated in Newai.

vii. 1982 Cartridge Tapered Roller Bearing in Technical Collaboration with

Brenco Incorporated of U.S.A.

viii. 1985 Technical Collaboration with NTN Corporation of Japan for Ball,

Cylindrical & Spherical Roller Bearing.

ix. 1995 ISO - 9001 Quality Management System Certification.

x. 1996 Technical collaboration with Izumi Kinzoku Kogyo Co. Ltd., Japan for

Machine Retrofitting.

xi. 2007 Third Plant inaugurated in Manesar.

xii. 2008 NBC receives TPM Excellence Award.

xiii. 2010 NBC receives Deming Award.



xiv. 2012 NBC receives the ACMA awards for Manufacturing and Technology

Excellence

1.3. Technical collaboration (i) BRENCO Incorporated of U.S.A. Since 1982 - For Cartridge Tapered Roller

Bearings for Railroad applications.

(ii) NTN Corporation of JAPAN Since 1985 - For Ball Bearings, Cylindrical &

Spherical Roller Bearings, JPU Bearings, Double Row Angular Contact Bearings,

Hub Bearings Since 1997 - for Tapered Roller bearings.

(iii) Izumi Kinzoku of JAPAN Since 1996 for remanufacturing, retrofitting and

overhauling of Grinding and Super-finishing machines for bearing races.

1.4. Main CustomersRolling Stock: -

DLW (Diesel Locomotive Work)

CLW (Chittaranjan Locomotive Works)

ICF (Integral Coach Factory, Chennai)

RCF (Rail Coach Factor, Kapurthala)

CIMMCO

BEML (Bharat Earth Movers, Bangalore)

TEXMACO

Hindustan Motors Ltd.

Maruti Udyog Ltd.

Mahindra & Mahindra

Automobiles-LCV: -

Ashok Leyland

Force Motors

Eicher Motors

Tata Motors

Automobiles-Two/ Three Wheelers:-

Bajaj Auto Ltd.

Hero Honda Motors Ltd.

Honda Motorcycle & Scooters India Ltd.



Suzuki Motorcycle India

Majestic Auto

Piaggio India Ltd.

Royal Enfield Ltd.

Yamaha Motors India Pvt. Ltd.

TVS

Tractors: -

Eicher

Escorts

HMT

International tractors

Mahindra & Mahindra

Punjab Tractors

TAFE

VST Tillers

Electric Motors & Pumps:-

Crompton Greaves

G.E. Motors

Kirloskar Electric

NGEF

MICO

Fans: -

Bajaj Electricals

Crompton Greaves

1.5. Manufacturing FacilitiesNBC has manufacturing facilities at Jaipur (established in 1946), Newai(established

in 1980) and Manesar (established in 2006). A fourth plant, a green field project, at

Savli in 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.

Jaipur Plant

Newai (Gunsi) Plant

Manesar Plant



1.5.1. Newai (Gunsi) Plant

Established in the year 1980-81 as an expansion project of NEI Ltd . The factory is

equipped with fully automated grinding lines with electronic in-process & post-

process gauging and centrally air-conditioned assembly lines with auto gauging and

test equipments for quality and reliability of the products,The plant is spread over a

covered area of 7,200 Sq. Meters.

1.5.2 Manesar Plant

NEI has set up its third Ball Bearing manufacturing plant in the fastest growing

industrial town of Manesar in Haryana. The plant is having a covered area of 5200 sq.

meters. with the most advanced and sophisticated machines imported from reputed

manufacturers from Europe and Japan .This plant is equipped with state of the art

fully automated grinding lines, assembly lines and inspection equipments.

Fig1.2: Manesar Plant

CHAPTER-2

NBC JAIPUR



2.1. IntroductionThis plant is located in the heart of Pink City of India, which is also famous for its

Tourists spots. Spread over a total area of 4,78,900 m2 and a covered area of 75,310

m2, Jaipur plant has state of the art manufacturing facilities and capable to

manufacture all types of Ball and Roller Bearings of NEI product range. . It has a

separate division to manufacture all these spread across large area.

Fig. 2.1: Jaipur Plant

Fig.2.2: Nbc Design and Development

The plant at Jaipur includes-

i. Ball Bearing

ii. Precision Ball Making

iii. Tapered Roller Bearing

iv. Railway Bearing



v. Research & Development

vi. Large diameter bearings

vii. SAP-ERP

2.2. Ball Bearing

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.

Type of Ball Bearing:-

a. Radial Ball Bearing

b. Angular Contact Bearing

c. Self-Aligning Two-Row Ball Bearing

Radial ball bearing Angular Contact Bearing Self-Aligning Two-Row Ball Bearing

(a) (b) (c)

Fig. 2.3: Ball Bearings

The initial technology was from Hoffman Manufacturing Company Ltd., U.K. a

collaboration, which continued for 20 years. They offer a wide range of both metric

and inch series deep groove ball bearings, angular contact ball bearings, self-aligning

ball bearings etc. With their tie up with the world's leading bearing manufacturing

company NTN Corporation, JAPAN, They have gained access to the most advanced

ball bearing technology i.e. thermo mechanical bearings (TMB) and tensioner

bearings available today and their wide range of ball bearings is increasing under this



collaboration. Precision ball bearing from 6mm bore to 160mm OD is manufactured

with latest advance techniques. The unit has advanced assembly line with auto

gauging and testing equipment. NEI has 22 automatic Grinding lines from M/s. NTN

& Izumi, Japan. All machines with in process & post process gauges to ensure

grinding accuracy. Use of High Quality coolants for consistent grinding quality and

surface finish. Complete automation by flex-link conveyor system. NEI has automatic

plant for Track Grinding, Bore Grinding and Honing, The latest advanced techniques

for manufacturing and Quality Assurances are implemented to meet the rapid increase

in demand for quality, diversity of specifications and new types of bearings. The plant

is spread over a covered area of 14,694 sq. meters.

2.3. Precision Ball Making Precision Steel balls up to 25 mm diameter for NEI bearings are being manufactured

in a separate well equipped factory. Precision quality balls are manufactured on

precision Grinding & Lapping machines to achieve super finished surface, accuracy

and roundness as per ISO standards. The plant is spread over a covered area of 4,700

sq.mtr.

Fig. 2.4: Steel Ball

2.4. Tapered roller bearing

Type of Tapered Roller Bearing

a. Single Row Tapered Roller Bearing

b. Double Row Tapered Roller Bearing



Single Row Tapered Roller Bearing Double Row Tapered Roller Bearing

(a) (b) Fig. 2.5: Tapered Roller Bearings

This plant with the most modern equipment was set up in the year 1968.

Manufactured at an ultra-modern plant, with technology obtained from our earlier

collaborators, Federal Mogul Corporation, USA and now with NTN Corporation,

JAPAN, these bearings are used by all major automobiles, truck and tractor

manufacturers in the country as original equipment. The above bearings are

manufacture in inch & metric series form 15.857mm bore to 95.25mm bore. For TRB

NEI has Automatic Grinding Lines with in-process & post process gauges. Complete

automation by Flex link conveyor. Crowning provision on Inner (Cone) & Outer

(Cup). Complete Automatic Line for Roll Grinding, Super finishing, Inspection and

Sorting imported from NTN, Japan automatic checking & prevention of inverted

roller & roller missing. Automatic checking of stand height, noise and run outs.

Presently under modernization and expansion plan the new latest state of the art

technology lines are installed. The plant is spread over a cover area of 11,652 sq. mtr.

2.5. Railway bearingRailway Bearings included in three sections

a. Roller Bearing & Axle Boxes

b. Spherical Roller Bearing

c. Cartridge Tapered Roller Bearing

2.5.1 Roller bearing & axle boxesWith 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.

Fig 2.6: Axle Boxes

The most of the production of this type of bearing for Indian Railways, Production of

the bearing started in 1952, on date plant is producing 100 different types of Axle Box

bearing, over a million NEI bearings and boxes are in service with the Indian

railways. New Automatic Grinding and Assembly Line has been purchased for

manufacturing of Axle Unit Bearings (DRAC bearings) from M/s Izumi Kinzoku.

2.5.2. Spherical roller bearingThe manufacture 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.

Fig 2.7: Railway Bearings



2.5.3. Cartridge tapered roller bearingFor fitment to the new BOX-N Uprated Wagons designed by the RDSO, NEI is the

only manufacturer in the country who is the first to indigenize these bearings to a high

percentage under collaboration with the largest manufacturer of these bearings in the

world. Production of these bearings is grease packed and requires no field lubrication

for a period of 7 year. The Railway Bearing Division is spread over a covered area of

1.2 acres.

2.6. 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 up to 2000 mm diameter. The largest bearing produced by NEI for

fitment to plate will 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

weighs 4.39 tones. The large diameter bearings are mainly produced out of case

carburizing steels, heat treated on special equipment andfurnaces developed by NEI.

The 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.

2.7. Research and development

2.7.1. Design and developmentComplete in-house facility for design & development of all types of bearings and

tooling is available. The design is done on CAD. The large diameter bearings and

tooling have been entirely designed and developed by NEI’s R&D at its Computer

center. Complete engineering and research facility is available to solve problem of

design development, manufacturing, installation and maintenance of bearings. With

the signing of the technical collaboration agreement with NTN CORPORATION

JAPAN & BRENCO IN CORPORATED OF USA, the capability to offer the finest

engineering services in the bearing industry has enhanced.



2.7.2. Machine buildingThe NEI has the capability of Machine Building to design, develop and manufacture

special purpose CNC grinding lines, HT lines, material handling equipment’s and

other special 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 M/c Building division. Machine

Building has the capability and supports the Manufacturing divisions by overhauling

and retrofitting of the existing equipment’s so that these are upgraded to help produce

quality and improve productivity. R& D is spread over a covered area of ½ acres.

2.8. SAP-ERPIn order to re-engineer and integrate the Business processes for Sales, Production,

Materials and Finance, NEI has successfully implemented SAP ERP.



CHAPTER 3

RAILWAY BEARING DIVISION

(SPHERICAL ROLLER BEARING)

3.1. IntroductionI did my training at Railway Bearing Division (Spherical Roller Bearing) .This

division is spread over covered area of 4,855 Sq. Meters. 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 .Spherical roller bearing has bore

(minimum) 40 mm and outer diameter (maximum) 420 mm. These bearings are used

by Indian Railway in all zones in the country as original equipment as well as in

other countries such as U.S., China, and Indonesia.

3.2. Spherical Roller BearingA spherical bearing is a bearing that 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.

Spherical Roller bearings for passenger coach applications are especially important

and require extremely high levels of performance, durability and reliability. In order

to achieve these high levels, NEI (NBC) performs strict inspection and quality control

at every stage of design, and production, from selection of material to the processing

technology used for manufacturing the bearings.

Spherical roller bearings have a large capacity for radial loads, axial loads in either direction, and complex loads. They are suited for the applications such as railways rolling stocks where vibrations and shock loads are encountered. All NBC spherical roller bearing are fitted with machined brass cages. Brass is the most preferred cage material for bearing used in railways all over the world. NBC spherical roller bearings for Meter Gauge and Broad gauge passenger coaches have symmetrical roller design. Where as in case of bearing used in Broad Gauge EMU, rollers are of asymmetric design.



Fig3.1: Spherical Roller Bearing

3.3. Bearing materialsThe functional performance and endurance of a dimensionally perfect bearing with

ideal internal geometries and surfaces, correct mountings, and professional operating

conditions are significantly influenced by characteristics of its material.

The major criteria to be considered for the satisfactory performance of bearing

including material selection and processing with resultant physical properties. Let’s

discuss material selection for spherical roller bearing at NBC –

Bearing contains varying amount of carbon, iron, chromium, manganese, phosphorus,

sulphur, silicon etc. Each of these elements plays a role in making final steel suitable

for bearings. Chromium and carbon allows deep hardening. The combination of

chromium, carbon & iron helps to minimize failure. As they increase the surface

resistance to abrasion & wear increase. In short, proper combination of all these

elements make final bearing steel which is tough under shocks, heavy loads & hard

enough to withstand fatigue. Generally bearings are made from bars. But now a day,

many manufacturers are making bearings by forging rings. The latest techniques

adopted recently are the “Vacuum Processing”. The bearing steel is made through

vacuum processing, which assists rod to be clean & free from defects & give

substantially larger bearing life.



Table 3.1 Contents of impurities in a Raw material

ELEMENT AMOUNT

Manganese 0.25 to 0.35

Silicon 0.025 to 0.35

Sulphur 0.025 max.

Phosphorus 0.025 max.

Nickel 0.025 max.

Copper 0.35 max.

Molybdenum 0.10 max.

3.3.1. Raw material for outer ring, inner ring and cagesAs railway bearing included in three sections-

Roller Bearing & Axle Boxes

Spherical Roller Bearing

Cartridge Tapered Roller Bearing.

A spherical roller bearing contains the following parts-

Main parts of Spherical Roller Bearings are follows-

(i) Races (outer and inner)

(ii) Rollers

(iii) Cage

The demand on the steel industry to provide higher quality alloy steels promoted the

development of the cold charges in the basic material-lined, electric arc furnaces.

These furnaces let higher-and lower grade alloy scarps be mixed with plain carbon

scarp; economical operation and product quality are achieved through proper selection

and weight control of these materials. Knowing the exactly chemistry of scarp charge

reduce the consumption of more costly alloys that are added to the melt and

minimizes the introduction of undesirable tramp alloying elements. A variety of steel

and brasses are used for different components for bearings depending upon the

properties required in the final product.



Table 3.2 Materials of Different components of a Bearing

Balls Ni-Cr Steel wire

Rollers High Carbon chrome steel rods

Races High carbon steel

Cage Brass and mild steel

NBC was the first one in India who made the cartridge tapered roller bearing with the

help of BRENCO Incorporated of USA.

3.4 Raw material suppliers

These are the industries which supply the forged raw material to NBC-

a) Ajanta turnings

b) Balaji engineering

c) Keshav engineering

d) Microtech engineering

e) Microtech rollers

The raw material first come in the inspection room and the following parts inspects-

a) Turned finish inner ring

b) Turned finish outer ring

c) Cage or retainer

d) Semi finish/Finish rollers

Parameters that need to be check:

For outer ring-

a) Width size

b) ID(Track Size)

c) ID roundness

d) OD Size

e) OD roundness



f) Eccentricity (Bore to OD)

g) Surface defects- free from damage, tool mark, black spot, rust, roughness, burr

etc.

h) Oiling

For inner ring-

a) Width size

b) Bore

c) Undercut size

d) Oil groove size

e) Surface defects

f) OD size

For SEMI-FINISH/FINISH ROLLER-

a) OD size

b) OD Ovality

c) OD Taper

d) Length

e) Recess Depth

f) Surface Roughness

g) Radius of large end

h) Radius of small end

i) Hardness

j) Oiling

For RETAINER-

a) Total width

b) Small bore diameter

c) Pocket length

d) OD size at top

e) Sheet thickness at bore

f) Visual inspection

g) No. of pockets

CHAPTER-4



MATERIAL USED IN BEARING

4.1. Bearing material

Bearing reliability begins with the material from which the product is made. The

material selection can have a dramatic impact on a bearing’s ability to meet the

application requirements. Additionally, the heat-treatment process that accompanies

material selection largely dictates durability by its impact on several bearing

characteristics, including hardness profile, bearing microstructure, final raceway

surface finish and residual stress.

Traditionally, Bearings have been produced from low carbon, carburizing grades of

steel. The introduction of carbon during manufacture, and the high alloys in the steel,

assures the proper combination of a hard, fatigue-resistant case and a tough, ductile

core. Benefits of casehardened bearings include:

Residual compressive stresses in the surface that retard propagation of fatigue cracks.

An enhanced ability to endure heavy shock loads as a result of the tough, ductile core.

Improved debris resistance due to the metallurgical characteristics of the surface

Tapered roller bearings have a spherical surface ground on the large ends of the

rollers. The radius of this surface is slightly less than the apex length (distance from

the roller large end to the apex). The roller large end makes point contact with the

cone large rib when under light load. Under heavier load, this contact area becomes

elliptical. The roller rib interface geometry promotes hydrodynamic lubrication in the

contact area. The seating force of the roller against the rib is normally small and

therefore contact stresses are relatively low. This is true whether pure radial load or

pure thrust load is involved.

4.2. Flow of Material in Bearing



Fig.4.1: Flow of Material in Bearing

CHAPTER-5



PROCESS OF MANUFACTURING

5.1. Manufacturing Processes of Spherical Roller Bearing

NBC gets forged and roller bearings from their vendors, as there are no separate dept.

for forging or rolling. Than they do carburizing or other heat treatment to strengthen

the bearing or finally grinding or other finishing operation is performed to make it

able to operate in automotive vehicle, railway etc. The processes through which

bearing has to go are shown in flow diagram below-

Fig.5.1: Manufacturing Processes of Spherical Roller Bearing

5.2. Heat treatment and laboratory



Heat treatment of bearing steel components necessitates heating and cooling under

controlled atmospheric conditions to impact the desired material characteristics and

properties such as hardness, a diffused high carbon surface layer, high fracture

toughness or ductility, high tensile strength, improved machinability, proper grain

size, or reduced stress state. The specific thermal cycles that produce these material

characteristics are:

(i) Annealing

(ii) Normalizing

(iii) Hardening

(iv) Carburizing

(v) Tampering

(vi) Stress Reliving.


Figure: 3.3Heat treatment sequence


Let’s discusses each process with respect to these parts for simplicity of understanding

Fig: 5.3: Flow diagram of heating sequence of spherical bearings

5.3. Carburizing

Carburizing is a is a heat treatment process in which iron or steel absorbs carbon liberated when

the metal is heated in the presence of a carbon bearing material, such as charcoal or carbon

monoxide, with the intent of making the metal harder. Depending on the amount of time and

temperature, the affected area can vary in carbon content. Longer carburizing times and higher

temperatures lead to greater carbon diffusion into the part as well as increased depth of carbon

diffusion. When the iron or steel is cooled rapidly by quenching, the higher carbon content on the

outer surface becomes hard via the transformation from austenite to martensite, while the core

remains soft and tough as a ferritic and/or pearlite microstructure.



The carburizing is performed 940º to 980ºc in rotary hearth furnace with time of 10hrs. But carburizing is done for only cup and cone with Air: LPG =10:1 (Endo Gas).

Fig.5.4: Rotary hearth furnace

5.4. Hardening Furnace

To control the mechanical properties, it is essential to start a structure with a structure of

austenite since it is state where the carbon atoms are distributed into the iron matrix uniformly.

The austenitic structure in steel is achieved by heating it and soaking at a temperature above

7230C, depending on the carbon percentage.

In hardening furnace “case hardening” of the job is carried out in the presence of R-Gas. R-Gas

is a mixture of CO+H2+N2+CO2+H2O. R-Gas is formed by the reaction of LPG with air. This

reaction is taken place in retort at a temperature of 950 0C in the presence of catalyst.

Hardening furnace has four chambers. First chamber is at 840 0C and rest three chambers are at

850 0C. After the hardening furnace bearing material (steel) is converted into austenite form.

5.5. Quenching

Quenching is a process of cooling a metal at a rapid rate. This is most often done to produce a

martensite transformation. In ferrous alloys, this will often produce a harder metal, while non-

ferrous alloys will usually become softer than normal. To harden by quenching, a metal (usually

steel or cast iron) must be heated above the upper critical temperature and then quickly cooled.



In NBC Oil is used in the quenching process and the oil is kept at a temperature of 25 0C.

Agitator is used to stir the oil in the oil quenching tank.

From the figure 4.3, we can find that when we rapidly cool austenite form then martensite will

form and it will have more hardness in comparison to austenite form. Then through the conveyor

job is sent to the washing tank which is held at a temperature near about 220C. The conveyor

speed is 400 mm/Min. Then drying is done with the help of air.

5.6. Tampering

Martensite formed during the quenching process is extremely hard and brittle, and lack

toughness. Thus these steels are not suitable for some baring applications requiring impact

resistance; hence a secondary heat treatment process called tempering is carried out on quenched

steel to achieve the necessary toughness and ductility by marginally sacrificing hardness. This

process also relives the internal stresses thus improving the ductility. The tempering temperature

is about 200 C for 2.5 hrs. The above mentioned time and temperatures during heat treatment

explanations are for cup, cone, and wear rings.

Fig.5.5: Tempering furnace

5.7. Rockwell hardness test



To see the effect of tampering on bearing races Rockwell hardness test is being used to check the

hardness of races before and after the tampering. Before the tampering hardness range lies

between is 62 to 64 HRC and after tampering hardness range is 60-62HRC. The overall effect of

tampering also affects the hardness and this reduced by 2HRC.

Principal of the Rockwell Test

The indenter moves down into position on the part surface

A minor load is applied and a zero reference position is established

The major load is applied for a specified time period (dwell time) beyond zero

The major load is released leaving the minor load applied

The resulting Rockwell number represents the difference in depth from the zero reference

position as a result of the application of the major load. If HRC doesn’t meet our requirements

then we reject the tampered lot. Behind this there may be following causes-

a) Manufacturing Fault

b) Furnace temperature fault

c) Tampering fault



Fig.5.6: Rockwell hardness test setup

5.8. Grinding Section

Grinding is a finishing process used to improve surface finish, abrade hard materials, and tighten

the tolerance on flat and cylindrical surfaces by removing a small amount of material. In

grinding, an abrasive material rubs against the metal part and removes tiny pieces of material.

The abrasive material is typically on the surface of a wheel or belt and abrades material in a way

similar to sanding. On a microscopic scale, the chip formation in grinding is the same as that

found in other machining processes. The abrasive action of grinding generates excessive heat so

that flooding of the cutting area with fluid is necessary.

During the grinding operations coolant is used regularly. Coolant is mixture of water and oil. In

coolant percentage of oil 3.5% and rest is water. For O.D grinding in N.E.I. Ltd. HOCUT B-60

oil is used.

The objectives of cooling is are-

i. In grinding operations, due to contact of grinding wheel and job they become hot so

cooling is necessary.

ii. The chip, which is produced by grinding also, flows away.

5.8.1. Operational step to grind Inner race:

Fig5.7: Process sequence

(a) O.D. grinding-



OD is the circumferential surface of the outer race of the bearing. The OD should be surface

finished since the bearing has to be assembled in machine. It is obtain in an OD grinding

machine. In this machine the outer race is rotated between two grinding wheel. The outer race is

passed in machine three times to get highly finished as follows:

1. Rough1

2. Rough2

3. Fine finish

(b) Face grinding-After hardening process the first of grinding is face grinding and this process is done on facing

wheel grinding machine by manual feeding of cup and cone. Facing wheel grinding machine

grind the face of races at an average speed of 225 races per hour with maximum capacity of 550

races per hour. After facing inspection of dimension also checked to ensure to quality of grinded

face.

(c)Flange grinding-

The flange should be surface finished since the bearing has to be assembled in machine. It is

obtain in the flange grinding machine. In this machine one grinding stone is used to cut and grind

the flange portion of cone.

NC Mode - AUTO

Feed Mode - AUTO

Override - 120% (used to change machine speed.)

Tool movement during grinding is in all three dimensional axes i.e. X, Y, Z axis.

(d) Bore grinding-Bore is the inner circumferential surface of the bearing. The bore should be surface finished

since the bearing has to be assembled in machine. It is obtain in the bore grinding machine. In

this machine the grinding stone is moved in X and Y axis.

Size Limit : +4 µm to -4 µm.



TOOL movement during grinding is in only two dimensional axes i.e. X, Z axis.

(e) Honing machine (super finishing)Honing is an abrasive machining process that produces a precision surface on a metal work piece

by scrubbing an abrasive stone against it along a controlled path. Honing is primarily used to

improve the geometric form of a surface, but may also improve the surface texture.

5.8.2. Operation steps to outer race grinding

Fig: 5.8: Process sequences for outer race grinding

(a) Face grinding-

Facing of outer ring(cup) also takes place between two facing wheel, out of which one wheel is hard and one wheel is soft. Soft wheel used to take into account wear resistance of hard wheel. After facing inspection takes place with the tolerance of 40 micrometers. Flange width also checked with the tolerance of 15 micrometers.

(b) Rail grinding-

Track is the path on which rollers will move so track of the cup should be grinded properly. So that rollers will move smoothly.



Fig: 5.9: Face grinding

(c) Honing machine (cup super finishing)As rollers will move on the track so the track surface should be super finished so the rollers will

move smoothly. For this purpose honing is done.

Now Cup & Cone are ready to send assembly section. They reached assembly section via

conveyor.

5.8.3. Operational step in grinding of roller

Fig: 5.10: Rollers of spherical bearing



Fig: 5.11: Process sequence for grinding of rollers

(a) Face Grinding-The face grinding is done after centerless grinding of rollers. Specially made machines used for face grinding.

Fig: 5.12: Face grinding of roller

(b) Body Grinding-Body grinding of spherical rollers is done by specific grinding wheels made for ths operation.

Fig: 5.13: Body grinding of rollers

(c) Roller super finishing (honing)- Mostly one or two stage super finishing machines are used for rollers. The rollers are supported

and driven by control wheels. The stone oscillates across the O.D.



Fig: 5.14: Roller super finishing

5.9. Assembly section

The assembly part in NEI is done manually. The parts after going through various in line

inspection or a separate inspection for all bearing components sent to assembly line. In assembly

line each parts width, bore, track is checked again through various gauges.

Assembly of Spherical Roller Bearings Components: -It includes

a) Inner race.

b) Outer race.

c) Roller section (Retainer Section).

d) Roller Cage.

Fig.5.15: Elements after assembly of spherical bearings



5.10. Maintenance and inspection section

5.10.1 For machines

Maintenance and inspection is that section where various types of machines, tools and machine

parts are inspected for life requirement and better working features. Various types of pressure

gauges, vibration inspection machines and the noise inspection machines are the special features

of this section.

Maintenance and inspection is that section where various types of machines, tools and machine

parts are inspected for life requirement and better working features. Various types of pressure

gauges, vibration inspection machines and the noise inspection machines are the special features

of this section.

The machines used in this section are as follows -

i. LATHE m/c,

ii. SHAPER m/c,

iii. BORING m/c,

iv. PLANNER m/c,

v. DRILLING m/c,

vi. MILLING m/c,

vii. Universal type,

viii. Vertical and Common type, Plain Milling m/c

5.10.2. For bearing components

All these inspections are done manually



Inline Inspection-after every specific operation there is checking of bearing components (1 out of

20) through gauging processes like width, track or bore gauge after width, bore or track grinding

Resp.

Final Inspection-when the complete grinding of a particular product is completed like for cone

all processes width, bore or track grinding is completed than it sent to final inspection.

In Final Inspection we detect crack check by two methods:

a. Crack check Machine - kerosene or magnetic flux is used;

b. Demagnetize Washing.

CHAPTER-6

MANUFACTURING & ASSEMBLY

6.1. Inner & Outer Ring Manufacturing



Fig.6.1: Flow Chart of Inner & Outer Ring Manufacturing

The contact surfaces of the bearing rings and rolling elements are subjected to repeated heavy

stresses, so they must maintain high precision and rotational accuracy. To accomplish this, the

rings and rolling elements must be made of a material that has high hardness, resistant to rolling

fatigue, wear resistant and has good dimensional stability.

High carbon chromium bearing steel (SUJ 2) deep hardened by the hardening method &case

hardening steel (SC/SCM/SNCM) with a hardened carburized outer layer are used for the rings

and rolling elements of standard bearings.

The most widely used and most suitable materials for rolling bearings are high carbon steels. The

most commonly used of these steels is SUJ2. For bearings with large cross section dimensions



SUJ3 or SUJ5 having good hardening properties are used. NBC uses high carbon steel for almost

all of spherical roller & cylindrical roller bearings.

For case hardening steel; Chrome Steel (SCr), Chrome Molybdenum Steel (SCM) and Nickel

Chrome Molybdenum Steel (SNCM) are used because of its combination of a hard surface layer

which has been carburized and hardened to an appropriate depth, and a relatively pliable inner

core, case hardening steel has excellent efficiency against shock load. NBC uses case hardening

steel for almost all of tapered roller bearings.

Since the life of the bearing steel is determined by the purity of cleanliness of steel the above

grade steels are low in non-metallic impurities & low in oxygen content because they are refined

by avacuum degassing process & outside hearth smelting process.

The Turning operations are divided into various lathe Operations viz. O.D., face, track &Bore.

All these operations are done on production lathe machines. The Hardening of steel is achieved

by heat treatment process in which the steel microstructure is manipulated by cycles of heating &

quick cooling to obtain the optimum hardness range for steel – usually on the order of 60 to 64

on Rockwell C Hardness Scale. When slowly quenched it would form Austenite & Pearlite

which is a partly hard and partly soft structure respectively. Hardening of steel requires a change

in structure from Body Centered Cubic Structure found at room temperature to Face Centered

Cubic Structure found in Austenite Region. When Steel is suddenly Quenched Marten site is

formed which is extremely strong and if steel is Quenched slowly then Pearlite is formed which

is extremely Soft.

6.2. Roller Manufacturing



Fig.6.2: Manufacturing of Roller

The Raw Material used (SUJ 2 Steel) for manufacturing of rollers is a speciallyformulated grade

of Steel. The Material is Supplies by rod. It is then cut to length &width on Production Lathe.

For Spherical Rollers or Tapered Rollers, The rod is then fed through a header. This coldforged

process produce “slugs” at an incredibly high speed. Rod is fed from decoilers into cold heading



machines where it is cut into blanks and then pressed between hemispherical dies or conical dies.

For Cylindrical Rollers the above procedure is not done.

The flash around the rollers produced during pressing is removed by filing plates indeburring

machines.These rough shaped spherical rollers have a ring around the middle. The next process

isto remove this ring by machining in rill-filing machine, equipped with one fixed and one

rotating cast iron rill-plate. Concentric grooves in the plate ensure that the whole roller surface is

machined to same extent and thus a spherical form is achieved

The next process for Rollers is grinding in which rollers are grind in the order: Face, O.D. and

I.D. The grinding process is done in two phases; one prior to Heat Treatment (RoughGrinding) &

one after the heat treatment process (Finish Grinding).Final inspection for size, form and surface

finish is carried out on a sample basis bymeans of high resolution microscopes and other

precision equipment because a tiniestdeviation even of the order of 1 Å (10-10m) in the

roundness of bearing element can havean impact on bearing quality. The rollers are then cleaned

and dispatched for bearingassembly operation.

6.3. Cage Manufacturing

Fig.6.3:Cage Manufacturing



The cages for various bearing sizes are manufacture from Cold Rolled (C.R.) & Cold Annealed

narrow width sheets IS 4397. The C.R. sheet is converted in the cage in Press Machine in

Successive Operations: Blanking, Punching, Forming (Pocketing) rivet holes and visual

inspection is carried for any deformity.

6.4. Roller Bearing Assembly Line

The assembly part in NEI is done manually. The parts after going through various in line

inspection or a separate inspection for all bearing components sent to assembly line. In assembly

line each parts width, bore, track is checked again through various gauges.

Flow Chart

Fig.6.4: Roller Bearing Assembly Line



CHAPTER-7

APPLICATIONS

While Engineered Surfaces have been successfully applied to a variety of components, our first

and most extensive experience is using these processes with anti-friction bearings. Timken

research revealed that modifying the topography of a bearing’s contact surfaces resulted in

significant improvement in overall performance.

Inadequate lubrication, poor maintenance, extreme operating environments and vibration can be

detrimental to bearing performance. Engineered Surfaces enable bearings to better resist these

potentially damaging environmental factors.

Real-world benefits have been demonstrated in rugged applications that include bearings used in

aircraft landing gear, heavy equipment drive trains and industrial rolling mills.

In many applications tapered roller bearings are used in back-to-back pairs so that axial forces

can be supported equally in either direction.

Pairs of tapered roller bearings are used in car and vehicle wheel bearings where they must cope

simultaneously with large vertical (radial) and horizontal (axial) forces. Applications for tapered

roller bearings are commonly used for moderate speed, heavy duty applications where durability

is required. Common real world applications are in agriculture, construction and mining

equipment, axle systems, gear box, engine motors and reducers.


http://www.timken.com/en-us/products/coatings/engineered/Pages/ESaircraft.aspx


CHAPTER-8

CONCLUSION

8.1. Training experience

My training period of 30 days turned out to be a wonderful experience both industrially and

learning wise; experiencing the functionalities of Heavy Fabrication Block, flow of knowledge

as well as decision making processes within the block. Working with the employees and learning

from them was such a life changing experience.

8.2. About reportThis report describes the NBC bearing industry and its technology. My Through this report, I

have tried to present a comprehensive study of the various functionalities and responsibilities of

NBC Bearings. Starting from the overview of the company till the explanation of various type of

process i.e. heat treatment, grinding, facing and the different type of machines used in that

processes like for grinder, machines for honing & super finishing machines are available, for

heat treatment rotary hearth furnace and tampering furnace and CNC machines. This report tries

to throw light on each and every aspect of the NBC Bearings.

Maximum of their work was done manually. While in railway bearing division, the whole

processing is automatic. But now days they are trying to set up new NOVA CNC machines. It

will reduce the human effort or will increase productivity up to a large extent. This setting up of

new nova machines will place the NBC at a position to compete with other worldwide bearing

manufacturing companies.



BIBLIOGRAPHY “Internet Guidelines”, http://www.google.com

Bearing Design in Machinery: Engineering Tribology and Lubrication by Avraham

Harnoy CRC Press, 25-Sep-2002

Ball and Roller Bearing: Theory,Design and Application Third Edition by Johannes

Brandlein, Paul Eichmann, Ludwig Hasbargen, Karl Weigand


http://www.google.com/


REFERENCES Wikipedia

www.slideshare.net

www.nbcbearing.com


http://www.nbcbearing.com/

http://www.slideshare.net/