its fully detailed description about manufacturing bearings in NBC (NEI) and flowchart which makes ease to learn assembly.

1. 1
A REPORT
ON
INDUSTRIAL TRAINING
done by
Name of student – mukesh kumar
College ID - 10ME030
At
Name of company - National Engineering Industries Ltd. (NEI),
Address - Khatipura Road,Jaipur -302 006
Phone : 2223221
Fax : 0141-2221926.2222259
E-mail : neisales@nbcbearings.i
Submitted to :-
Department of Mechanical Engineering
Anand International College of Engineering
Jaipur-303012
(Approved to AICTE, New Delhi and Affilated to Rajasthan Technical University, Kota)
June/July 2014
.

2. 2
CERTIFICATE

3. 3
BONAFIDE CERTIFICATE
Certified that this industrial training is a work of mukesh kumar, Anand International College
of Engineering ID-10EDAME030 who carried out the INDUSTRIAL TRAINING at
National Engineering Industries Ltd. (NEI),. Khatipura Road, Jaipur-302006
Co-ordinator

4. 4
PREFACE
As per the requirement of B. Tech. Course, National Engineering Industries Ltd. (NEI),
Jaipur has been kind enough to permit me to complete my Practical Training under
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 summer 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.

5. 5
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 viable 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. PAWAN NAMA my project head, Mr. RAKESH
OSWAL(HOD), who gave me opportunity to work in his department and guided me through
my project 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 project 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.

6. 6
CONTENTS
Chapter No. Topic PageNo.
1. DEFINITION OF INDUSTRY 7
2. INTRODUCTION OF NEI 8
3. INTRODUCTION OF BEARING 8
4. INTRODUCTION OF BALL BEARING 11
5. MANUFACTURING PROCESS OF BALL BEARING
a. Inner track wheel
b. Outer track wheel
c. Cage
d. Balls
e. Rivets
6. TROUBLE SHOOTING 31
7. CONCLUSION 33

7. 7
DEFINITION OF INDUSTRY
Industry can be defined as:
‘’Any type of Economic Activity producing GOODs or SERVICES‛’
‘‘It is part of a chain – from raw materials to finished product, finished product to
service sector, and service sector to research and development.‛’
‘‘It includes AGRICULTURE, MANUFACTURING and SERVICES‛’
‘‘Industry varies over time and between different countries‛’
Industrial linkage:
‘‘When one Industry depends on the output of another‛’
This can cause problems if one industry has production problems or closes down
The CAR INDUSTRY is a good example – each component (engine parts, lights, body etc.)
may be produced by a different company before it goes to the ASSEMBLY PLANT.
BEARING INDUSTRY GLOBAL SCENERIO :
The world Market of quality Bearing is very vast. The Big players of bearing sector are
present in U.S.A, Russia, Japan, China and Eastern Europe. Some of leading bearing
Manufacturers are: -
- NSK Japan
- NTN Japan
- KOYA Seiko Japan
- FAG Germany
- SKF Sweden
- NRB France
- Timken USA
There are few of leading bearing manufacturer present in India. Most of the big player is
having either technical or financial Collaboration with leading Auto Manufacturer.
International Collaboration gives Access to best technology in the world.

8. 8
BEARING INDUSTRY INDIAN SCENERIO:
The Indian Bearing Industry is estimated at Rs. 30 Billion Approximately. The Industry has
established a highly diversified product range of around 1000 type of Bearing having High
Volume Demand. As much as 70% of the total
Demand for common varieties and size of bearing is met by the domestic Industry, and the
remaining demand to the tune of 30% is imported essentially for Industrial Application and
special purpose.
The Indian bearing Industry can be divided in to the organized sector and un-organized
sector. The organized sector primarily caters to the original equipment Manufacturer (OEM)
Segment, which predominantly comprises automotive industries and other mechanical
Industrial users. The replacement market is dominated by unorganized Sector.
ABOUT NEI:
Bearing in India started with the setting up of manufacturing unit in JAIPUR by the Birla
Group in 1946 under the name of "National Bearing Company Ltd."
The 1st Bearing was manufactured in 1950 with a modest start of 30 thousand bearing in 19
Sizes. The Bearing Races (Soft) was Manufactured by the Tiny Unit in the Small Scale
Sector at Jaipur during 1970 on Job Work basis.
It is a view to utilize the end piece of the Stainless steel tube which could not be fed to the
Multi operation of National Engineering Industries Jaipur.
There after there is a continuous growth of this Industry and now it has grown to a level that
Almost All the Leading Manufacturer of the country are procuring Soft Bearing Races from
JAIPUR. The National Engineering Industries procure lakhs of Ring every month from these
Bearing Race Manufacturing Unit.
The other leading manufacturer like S.K.F., FAG, TATA Bearing, NBC are also procuring
the Bearing races from Jaipur. In addition to above, the Small Scale Units manufacturing
Bearing in the state of Rajasthan, Delhi, Gujarat and Punjab also purchasing Bearing Races
and components from Jaipur.
BEARING:-
A bearing is a device to allow constrained relative motion between two or more parts,
typically rotation or linear movement.

9. 9
Bearings may be classified broadly according to the motions they allow and according to
their principle of operation as well as by the directions of applied loads they can handle.
TYPES:-
There are many different types of bearings.
Type Description Friction
Stiffness
† Speed Life Notes
Plain
bearing
Rubbing
surfaces,
usually with
lubricant; some
bearings use
pumped
lubrication and
behave
similarly to
fluid bearings.
Depends on
materials and
construction,
PTFE has
coefficient of
friction
~0.05-0.35,
depending
upon fillers
added
Good,
provided
wear is
low, but
some
slack is
normally
present
Low to
very
high
Low to very
high - depends
upon application
and lubrication
Widely used,
relatively
high friction,
suffers from
stiction in
some
applications.
Depending
upon the
application,
lifetime can
be higher or
lower than
rolling
element
bearings.
Rolling
element
bearing
Ball or rollers
are used to
prevent or
Rolling
coefficient of
friction with
Good,
but some
slack is
Moderat
e to high
(often
Moderate to
high (depends
on lubrication,
Used for
higher
moment

10. 10
minimize
rubbing
steel can be
~0.005
(adding
resistance
due to seals,
packed
grease,
preload and
misalignmen
t can
increase
friction to as
much as
0.125)
usually
present
requires
cooling)
often requires
maintenance)
loads than
plain
bearings with
lower friction
Jewel
bearing
Off-center
bearing rolls in
seating
Low
Low due
to flexing
Low
Adequate
(requires
maintenance)
Mainly used
in low-load,
high
precision
work such as
clocks. Jewel
bearings may
be very
small.
Fluid
bearing
Fluid is forced
between two
faces and held
in by edge seal
Zero friction
at zero
speed, low
Very
high
Very
high
(usually
limited
to a few
hundred
feet per
second
at/by
seal)
Virtually infinite
in some
applications,
may wear at
startup/shutdow
n in some cases.
Often negligible
maintenance.
Can fail
quickly due
to grit or dust
or other
contaminants
.
Maintenance
free in
continuous
use. Can
handle very
large loads
with low
friction.
Magneti
c
bearings
Faces of
bearing are
kept separate
by magnets
(electromagnet
s or eddy
currents)
Zero friction
at zero
speed, but
constant
power for
levitation,
eddy
currents are
often
induced
when
movement
Low
No
practical
limit
Indefinite.
Maintenance
free. (with
electromagnets)
Active
magnetic
bearings
(AMB) need
considerable
power.
Electro
dynamic
bearings
(EDB) do not
require
external

11. 11
occurs, but
may be
negligible if
magnetic
field is
quasi-static
power.
Flexure
bearing
Material flexes
to give and
constrain
movement
Very low Low
Very
high.
Very high or
low depending
on materials and
strain in
application.
Usually
maintenance
free.
Limited
range of
movement,
no backlash,
extremely
smooth
motion
†Stiffness is the amount that the gap varies when the load on the bearing changes, it is distinct
from the friction of the bearing.
Table 1: Typesof bearing
INTRODUCTION OF BALL BEARING
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation
between the bearing races.
The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
It achieves this by using at least two races to contain the balls and transmit the loads through
the balls. In most applications, one race is stationary and the other is attached to the rotating
assembly (e.g., a hub or shaft). As one of the bearing races rotates it causes the balls to rotate
as well. Because the balls are rolling they have a much lower coefficient of friction than if two
flat surfaces were sliding against each other.
Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element
bearings due to the smaller contact area between the balls and races. However, they can
tolerate some misalignment of the inner and outer races.
COMMON DESIGNS
There are several common designs of ball bearing, each offering various trade-offs. They can
be made from many different materials, including: stainless steel, chrome steel,

12. 12
and ceramic(silicon nitride (Si3N4)). A hybrid ball bearing is a bearing with ceramic balls and
races of metal.
ANGULAR CONTACT
An angular contact ball bearing uses axially asymmetric races. An axial load passes in a
straight line through the bearing, whereas a radial load takes an oblique path that tends to
want to separate the races axially. So the angle of contact on the inner race is the same as that
on the outer race. Angular contact bearings better support "combined loads" (loading in both
the radial and axial directions) and the contact angle of the bearing should be matched to the
relative proportions of each. The larger the contact angle (typically in the range 10 to 45
degrees), the higher the axial load supported, but the lower the radial load. In high speed
applications, such as turbines, jet engines, and dentistry equipment, the centrifugal forces
generated by the balls changes the contact angle at the inner and outer race. Ceramics such
as silicon nitride are now regularly used in such applications due to their low density (40% of
steel). These materials significantly reduce centrifugal force and function well in high
temperature environments. They also tend to wear in a similar way to bearing steel—rather
than cracking or shattering like glass or porcelain.
Most bicycles use angular-contact bearings in the headsets because the forces on these
bearings are in both the radial and axial direction.
AXIAL

13. 13
An axial ball bearing uses side-by-side races. An axial load is transmitted directly through the
bearing, while a radial load is poorly supported and tends to separate the races,so that a larger
radial load is likely to damage the bearing.
DEEP-GROOVE
In a deep-groove radial bearing, the race dimensions are close to the dimensions of the balls
that run in it. Deep-groove bearings can support higher loads.
CONSTRUCTION TYPES
CONARD
The Conrad-style ball bearing is named after its inventor, Robert Conrad, who was awarded
British patent 12,206 in 1903 and U.S. patent 822,723 in 1906. These bearings are assembled
by placing the inner race into an eccentric position relative to the outer race, with the two
races in contact at one point, resulting in a large gap opposite the point of contact. The balls
are inserted through the gap and then evenly distributed around the bearing assembly, causing
the races to become concentric. Assembly is completed by fitting a cage to the balls to
maintain their positions relative to each other. Without the cage, the balls would eventually
drift out of position during operation, causing the bearing to fail. The cage carries no load and
serves only to maintain ball position.
Conrad bearings have the advantage that they are able to withstand both radial and axial
loads, but have the disadvantage of lower load capacity due to the limited number of balls
that can be loaded into the bearing assembly. Probably the most familiar industrial ball
bearing is the deep-groove Conrad style. The bearing is used in most of the mechanical
industries.
SLOT-FILL
In a slot-fill radial bearing, also referred to as a full complement design, the inner and outer
races are notched on one face so that when the notches are aligned, balls can be slipped in the
resulting slot to assemble the bearing. A slot-fill bearing has the advantage that the entire
groove is filled with balls, called a full complement, resulting in a higher radial load capacity
than a Conrad bearing of the same dimensions and material type. However, a slot-fill bearing
cannot carry a significant axial load on the loading slot side. Also, the slots cause a
discontinuity in the races that has a small but adverse effect on strength.
ROWS

14. 14
There are two row designs: single-row bearings and double-row bearings. Most ball bearings
are a single-row design, which means there is one row of bearing balls. This design works
with radial and thrust loads. A double-row design has two rows of bearing balls. Their
disadvantage is they need better alignment than single-row bearings.
FLANGED
Bearings with a flange on the outer ring simplify axial location. The housing for such
bearings can consist of a through-hole of uniform diameter, but the entry face of the housing
(which may be either the outer or inner face) must be machined truly normal to the hole axis.
However such flanges are very expensive to manufacture. A more cost effective arrangement
of the bearing outer ring, with similar benefits, is a snap ring groove at either or both ends of
the outside diameter. The snap ring assumes the function of a flange.
CAGED
Cages are typically used to secure the balls in a Conrad-style ball bearing. In other
construction types they may decrease the number of balls depending on the specific cage
shape, and thus reduce the load capacity. Without cages the tangential position is stabilized
by sliding of two convex surfaces on each other. With a cage the tangential position is
stabilized by a sliding of a convex surface in a matched concave surface, which avoids dents
in the balls and has lower friction. Caged roller bearings were invented by John Harrison in
the mid-18th century as part of his work on chronographs. Caged bearings were used more
frequently during wartime steel shortages for bicycle wheel bearings married to replaceable
cups.
CERAMIC HYBRID BALL BEARINGS USING CERAMIC BALLS
Ceramic bearing balls can weigh up to 40% less than steel ones, depending on size and
material. This reduces centrifugal loading and skidding, so hybrid ceramic bearings can
operate 20% to 40% faster than conventional bearings. This means that the outer race groove
exerts less force inward against the ball as the bearing spins. This reduction in force reduces
the friction and rolling resistance. The lighter balls allows the bearing to spin faster, and uses
less energy to maintain its speed. While ceramic hybrid bearings use ceramic balls in place of
steel ones, they are constructed with steel inner and outer rings; hence the hybrid designation.

15. 15
SELF-ALIGNING
Self-aligning ball bearings, such as the Wingquist bearing, are constructed with the inner ring
and ball assembly contained within an outer ring that has a spherical raceway. This
construction allows the bearing to tolerate a small angular misalignment resulting from
deflection or improper mounting.
OPERATING CONDITION
LIFESPAN
The calculated life for a bearing is based on the load it carries and its operating speed. The
industry standard usable bearing lifespan is inversely proportional to the bearing load cubed.
Nominal maximum load of a bearing (as specified for example in SKF datasheets), is for a
lifespan of 1 million rotations, which at 50 Hz (i.e., 3000 RPM) is a lifespan of 5.5 working
hours. 90% of bearings of that type have at least that lifespan, and 50% of bearings have a
lifespan at least 5 times as long.
The industry standard life calculation is based upon the work of Lundberg and Palmgren
performed in 1947. The formula assumes the life to be limited by metal fatigue and that the
life distribution can be described by a Weibull distribution. Many variations of the formula
exist that include factors for material properties, lubrication, and loading. Factoring for
loading may be viewed as a tacit admission that modern materials demonstrate a different
relationship between load and life than Lundberg and Palmgren determined.
FAILURE MODES
If a bearing is not rotating, maximum load is determined by force that causes plastic
deformation of elements or raceways. The identations caused by the elements can concentrate
stresses and generate cracks at the components. Maximum load for not or very slowly
rotating bearings is called "static" maximum load. For a rotating bearing, the dynamic load
capacity indicates the load to which the bearing endures 1.000.000 cycles.
If a bearing is rotating, but experiences heavy load that lasts shorter than one revolution,
static max load must be used in computations, since the bearing does not rotate during the
maximum load.

16. 16
Maximum load
In general, maximum load on a ball bearing is proportional to outer diameter of the bearing
times width of bearing (where width is measured in direction of axle).
Lubrication
For a bearing to operate properly, it needs to be lubricated. In most cases the lubricant is
based on elastohydrodynamic effect (by oil or grease) but working at extreme temperatures dry
lubricated bearings are also available.
For a bearing to have its nominal lifespan at its nominal maximum load, it must be lubricated
with a lubricant (oil or grease) that has at least the minimum dynamic viscosity (usually
denoted with the Greek letter ) recommended for that bearing. The recommended dynamic
viscosity is inversely proportional to diameter of bearing. The recommended dynamic
viscosity decreases with rotating frequency. As a rough indication: for less than 3000 RPM,
recommended viscosity increases with factor 6 for a factor 10 decrease in speed, and for more
than 3000 RPM, recommended viscosity decreases with factor 3 for a factor 10 increase in
speed.
For a bearing where average of outer diameter of bearing and diameter of axle hole is 50 mm,
and that is rotating at 3000 RPM, recommended dynamic viscosity is 12 mm²/s. Note that
dynamic viscosity of oil varies strongly with temperature: a temperature increase of 50–70
°C causes the viscosity to decrease by factor 10.
If the viscosity of lubricant is higher than recommended, lifespan of bearing increases,
roughly proportional to square root of viscosity. If the viscosity of the lubricant is lower than
recommended, the lifespan of the bearing decreases , and by how much depends on which
type of oil being used. For oils with EP ('extreme pressure') additives, the lifespan is
proportional to the square root of dynamic viscosity, just as it was for too high viscosity,
while for ordinary oil's lifespan is proportional to the square of the viscosity if a lower-than-
recommended viscosity is used.
Lubrication can be done with a grease, which has advantages that grease is normally held
within the bearing releasing the lubricant oil as it is compressed by the balls. It provides a
protective barrier for the bearing metal from the environment, but has disadvantages that this
grease must be replaced periodically, and maximum load of bearing decreases (because if
bearing gets too warm, grease melts and runs out of bearing). Time between grease
replacements decreases very strongly with diameter of bearing: for a 40 mm bearing, grease
should be replaced every 5000 working hours, while for a 100 mm bearing it should be
replaced every 500 working hours. Lubrication can also be done with an oil, which has
advantage of higher maximum load, but needs some way to keep oil in bearing, as it normally
tends to run out of it. oil quality; therefore, the oil is usually changed less frequently than the
oil in bearings.

17. 17
DIRECTION OF LOAD
Most bearings are meant for supporting loads perpendicular to axle ("radial loads").
Whether they can also bear axial loads, and if so, how much, depends on the type of
bearing. Thrust bearings (commonly found on lazy susans) are specifically designed for axial
loads.
For single-row deep-groove ball bearings, SKF's documentation says that maximum axial
load is circa 50% of maximum radial load, but it also says that "light" and/or "small" bearings
can take axial loads that are 25% of maximum radial load.
For single-row edge-contact ball bearings, axial load can be circa 2 times max radial load,
and for cone-bearings maximum axial load is between 1 and 2 times maximum radial load.
If both axial and radial loads are present, they can be added vectorially, to result in total load
on bearing, which in combination with nominal maximum load can be used to predict
lifespan. However, in order to correctly predict the rating life of ball bearings the ISO/TS
16281 should be used with the help of a calculation software.
AVOIDING UNDESIRABLE AXIAL LOAD
The part of a bearing that rotates (either axle hole or outer circumference) must be fixed,
while for a part that does not rotate this is not necessary (so it can be allowed to slide). If a
bearing is loaded axially, both sides must be fixed.
If an axle has two bearings, and temperature varies, axle shrinks or expands, therefore it is
not admissible for both bearings to be fixed on both their sides, since expansion of axle
would exert axial forces that would destroy these bearings. Therefore, at least one of bearings
must be able to slide.
A 'freely sliding fit' is one where there is at least a 4 µm clearance, presumably because
surface-roughness of a surface made on a lathe is normally between 1.6 and 3.2 µm.
FIT
Bearings can withstand their maximum load only if the mating parts are properly sized.
Bearing manufacturers supply tolerances for the fit of the shaft and the housing so that this
can be achieved. The material and hardness may also be specified.
Fittings that are not allowed to slip are made to diameters that prevent slipping and
consequently the mating surfaces cannot be brought into position without force. For a bearing
to have its nominal lifespan at its nominal maximum load, it must be lubricated with a
lubricant (oil or grease) that has at least the minimum dynamic viscosity (usually denoted
with the Greek letter ) recommended for that bearing.

18. 18
MANUFACTURING OF BALLBEARING
Ball bearings are at the heart of almost every product with a rotating shaft .Most bearing
specifications and manufacturing tolerances are quantified in one-ten thousandths of an
inch (1/10,000) by ABMA; every manufacturing process is 100% checked and feedback
provided to ensure the integrity of the process and product.
Note: A micron (an abbreviation for micrometers) is one-millionth of a meter, or,
25,400 microns equals one (1) inch.
REPEATABILITY IN THE MANUFACTURING PROCESS
Predictable uniformity, or repeatability, in the manufacturing process is crucial to ensuring
consistent bearing performance. If variations occur in the manufacturing process from part
to part, the production line may make bearings that fall within the complete spectrum of
the allowable tolerance standards. That inconsistency-- producing parts that go from one
end of the range to the other--can lead in turn to variations in the performance of each
bearing, either individually or from lot to lot. The narrower the variation in each step of
the manufacturing process, the greater the consistency of each

19. 19
Manufacturing Flow Chart
Forged Rings (De-scaled) as Raw Material.
(SAE 52100 steel)
Turning Operation
Center Less Grinding
Heat Treatment
Hardness testing
Rough Grinding
Finish Grinding
Honing & Super Finishing
Washing
Application of rust preventive
Ready for dispatch to assembly

20. 20
Ball Bearing Materials
Ball bearings are generally made of high carbon steels, such as AISI 52100(fifty-two,
one hundred). One of the factors that determine the life of the bearing steel (thus the
bearing itself) is the purity or cleanliness of the steel. The 52100 steel are subjected to a
rigorous purification process with stringent controls in order to meet the ever-increasing
standards for cleanliness–eliminating nonmetallic inclusions or impurities. These
impurities are removed through various processes such as vacuum degassing and
consumable-electrode vacuum melting (CEVM), to name just two of the processes referred
to when discussing the merits and cleanliness of bearing steel.
The hardening of the steel is achieved by a heat treating process in which the steel
microstructure is manipulated by cycles of heating and quick cooling to obtain the
optimum hardness range for the steel–usually on the order of 60to 64 on the
Rockwell C Hardness scale. Penetration hardness tests (such as Rockwell or Brinell )
provide the means to estimate the actual hardness of metals.
Raw Material for bearings Races:
For Outer and inners the suggested raw material is SAE 52100 conforming to following
chemical
compositions Element C Si Mn S P Cr.
Minimum .98 .15 .25 -- -- 1.30
Maximum 1.10 .35 .45 0.025 0.025 1.60
Oxygen content; Not More than 15 ppm
Micro Inclusions
Inclusion type Series
Thin Thick
(A) Sulphides 2.5 1.5
(B) Alumina 2.0 1.0
(C) Silicate 0.5 0.5
(D) Globular Oxide 1.0 1.0

21. 21
TURNING SECTION
Both the inner and outer rings are usually machined from the outer and Inner races are
manufactured from SAE 52100 steel, the raw material used in the section has been
considered as forged rings.
The turning operations are divided into various lathe operations, viz. O.D., face, track
and Bore. All these operations are done on production lathe machines. These lathe
machines offered in the project are production machines wherein individual job/
process sequence has to be set before every new batch is taken up.
HEAT TREATMENT
Hardness is a function of and brittle structure. When slowly quenched it would form
Austenite and Pearlite which is a partly hard and partly soft structure. When the
cooling rate is the Carbon content of the steel. Hardening of steel requires a change
in structure from the body-centered cubic structure found at room temperature to the
face-centered cubic structure found in the Austenitic region. The steel is heated to
Austenitic region. When suddenly quenched, the Martensite is formed. This is a
verystrong extremely slow then it would be mostly Pearlite, which is extremely soft.
The soft machined material is feed in the furnace and washed at 600 C, then send to a
chamber where the material heated in four chambers the first chamber has the temperature
8400 C and further chamber contains the 8500 C temperature.
Then it dipped into an oil tank at temperature 250C where the material get quenched then it
washed and then it tempered in water about 90 min. at temperature 1050 C .

22. 22
QUENCHING MEDIA
Quenching is the act of rapidly cooling the hot steel to harden the steel.
Oil:
Oil is used when a slower cooling rate is desired. Since oil has a very high boiling
point, the transition from start of Martensite formation to the finish is slow and this
reduces the likelihood of cracking. Oil quenching results in fumes, spills and sometimes
a fire hazard Austenite at room temperature.
Different alloys. The reason to alloy steels is not to
increase their strength, but increase their harden ability – the ease with which full
hardness can be achieved throughout the material. Usually when hot steel is quenched, most
of the cooling happens at the surface, as does the hardening. The propagates into the depth of
the material. Alloying helps in the hardening and by determining the right alloys one can
achieve the desired properties for the particular application. Such alloying also helps in
reducing the need for a rapid quench cooling – thereby eliminate distortions and potential
cracking. In addition, thick sections can be hardened fully.
Quenches are usually done to room temperature. Most medium carbon steels and low alloy
steels undergo transformation to 100% Martensite at room temperature. However, high
carbon and high alloy steels have retained To eliminate retained Austenite, the quench
temperature has to be lowered. This is the reason to use cryogenic quenching.
NITROGEN METHANOL SYSTEM
The above system comprise of Methanol Tank 200 liters SS 2.5 mm corrugated, Methanol
Flow Meter 0.50 to 5.2 per hour, Solenoid Valve, Needle Valves, all interconnected by
copper piping duly mounted on a stand with Nitrogen Pressure Regulator and Flow meter to
read 2 to 5 m3/hr.
GRINDING SECTION
The next stage is grinding, in order to give the rings the right form and dimensions.
The first operation on inner and outer rings is face grinding. Both faces are ground
simultaneously to give the final width.

23. 23
Face is the surface at side of the inner and outer race , face should be finished indeed to get
the desire width of the bearing and since the bearing is a mating part and it has to be
assembled somewhere in the machine where it should be fit precisely.
Manufacturing Process ofball bearing
Input Wire Rod as Raw Material.
(SAE 52100 Steel)
Shearing & Heading operation
On Ball Header Machine
Deburring on Vibro Benz Machine
Flushing of excess material after the
Ball forged in cold header
Heat treatment of ball
Lapping in Ball Lapping machine
Inspection for checking
Hairline cracks
Lapping of balls in
Tumbling barrel
Magnetic Crack Testing and
Washing
Application of rust preventive and
Packing

24. 24
The raw material used in the manufacture of balls is a specially formulated grade of
steel ringaroundthe to remove this ring. wire. The raw material is supplied from either
wire or rod. It is then cut to length and the width is a small percentage larger than the
width of the finished ball. The wire or rod is then fed through a header. This cold
forged processproduces"slugs"at an incredibly high speed. Wire is fed from decoilers
into cold heading machines where it is cut into blanks then pressed into between
hemispherical dies, The flash around the balls produced during pressing is removed
by filing plates in deburring machines.
Heat Treating Balls
BallFlashing Operation
.
The balls are then machined in rill-filing machines, equipped with one fixedand one
rotating cast iron rill-plate. Concentric grooves in the plates ensure that the whole
ball surface is machined to the same extent and thus a spherical form is achieved.

25. 25
Final inspection for size, form and surface finish is carried out on a samplebasis by
means of microscopes and other precision equipment. The balls are then cleaned and
packed ready for bearing assembly operations. The tiniest deviation in the roundness
of bearing elements can have an impact on bearing quality. Periodic form deviations
in the range of 1angstrom 10-10 m may influence bearing quality.
CAGE MANUFACTURING
Flow chart
Raw material
(narrow width CR sheet)
Blanking and punching
Forming (pocketing)
Inspection and batch checking
Shot blasting virbro
Assembly in assy. shop
The cages for various bearings sizes are manufactured from Cold Rolled narrow width
sheets IS 4397 cold rolled, cold annealed sheets, and The CRsheet is converted in the
cage in Press machines in successive press operations:
Blanking, Punching, forming (pocketing) rivet holes and visual inspection is carried for any
deformity. Cages are manufactured from cold rolled steel strip. Presses with progressiveor,
alternatively, transfer tools are used to produce cages halves from the strip. After surface
treatment and cleaning, the cage halves are coated with preservative and packed for
transport to the assembly plant.

26. 26
RIVET MANUFACTURING
Flow chart
Raw material
(wire EN 8)
Heading in ball header
Deburring in vibrobenz machine
Rust preventive oiling
Ready for assembly
The rivets are manufactured from wire rods, the wires is cut in required size in rivet
header machines, then in the vibro machines it is super finished. There is no grinding
operation involved.
PROCESS OF MAKING A BEARING

27. 27
FLOW CHART
Cage Rivet Outer Inner Balls
Put inner in outer
Insert balls
put under riveting machine
riveting
Washing of bearing
Demegnetizing
Clearance testing
Packaging of bearing in pillow wrapping machine
Ready to dispatch

28. 28
Finally the rings, balls and cage - which have been manufactured in different locations -
come together for automatic assembly. Raceway diameters of inner and outer rings are
measured separately. By selecting suitable combinations of ring and ball sizes, the
required internal clearance is obtained. Balls are fed between the rings and spaced
equally before the two cage halves are fitted and then riveted together.
Prior to automatic assembly the rings are optically inspected. After washing, the final
inspection sequence starts. This consists of a number of automated stations, which check
running accuracy, vibration level, and outside and bore diameters, as well as radial
clearance of the bearings. The bearings are then automatically washed, coated with
preservative, greased and fitted with seals or shields, before being packed according to
customer requirements.

29. 29
Materials
Material comparison for common bearing balls]
Material
UNS
52100
Stainle
ss
steel
440C
M50 BG-42
REX-
20
440ND
UR
Hayne
s 25
Si3N4 BECU 455 C276
Hardness
[HRC]
60 58 62 62 66 60 50 70 40 50 40
Temperat
ure limit
[°F]
300 300 400 400 600 300 1200 1500 400 500 1000
Corrosion
resistanc
e
1 3 1 2 1 4 5 5 1 4 5
Cost 1 1 1 2 3 1 5 5 3 2 4
Availabili
ty
1 1 2 2 2 4 5 3 3 2 4
Magnetic
Magne
tic
Magne
tic
Magne
tic
Magne
tic
Magne
tic
Magne
tic
Non-
magne
tic
Non-
magne
tic
Non-
magne
tic
Magne
tic
Magne
tic
Size limit None None None None None None
1.5 in
(38 m
m)
No
Torqu
e Tube
None None
5 in
(130 m
m)
Relative
load
3 2 4 4 5 3 1 5 1 1 1

30. 30
Bearing Visual Defects:
Appearance Cause Action Photo
Small indentations
around the
raceways and
rolling elements.
Dull, worn
surfaces.
Lack of
cleanliness
before and
during mounting
operation.
Do not unpack
bearing until just
before it is to be
mounted. Keep
workshop clean
and use clean
tools.
Outer ring of a spherical
roller bearing with
raceways that have been
worn by abrasive
particles. It is easy to
feel where the dividing
line goes between worn
and unworn sections.
Grease discoloured
green.
Ineffective seals Check and
possibly improve
the sealing.
Lubricant
contaminated by
worn particles
from brass cage
Always use fresh,
clean lubricant.
Wipe the grease
nipples. Filter the
oil.
Appearance Cause Action Photo
Worn, frequently
mirror-like, surfaces;
at a later stage blue
to brown
discoloration.
Lubrication has
gradually been
used up or has
lost its lubricating
properties.
Check that the
lubricant reaches
the bearing.
More frequent
relubrication.
Outer ring of a
spherical roller bearing
that has not been
adequately lubricated.
The raceways have a
mirror finish.

31. 31
Appearance Cause Action Photo
Depressions in raceways.
These depressions are
rectangular in roller bearings
and circular in ball bearings.
The bottom of these
depressions may be bright or
dull and oxidized.
The bearing
has been
exposed to
vibration while
stationary.
Secure the
bearing during
transport by
radial
preloading.
Provide a
vibration-
damping base.
Where possible,
use ball
bearings
instead of roller
bearings.
Employ oil bath
lubrication,
where possible.
Outer ring of taper
roller bearing
damaged by
vibration during
operation.
Vibration damage to
the ring of a
cylindrical roller
bearing. The damage
has arisen while the
bearing was not
running.
Inner and outer ring
of a cylindrical roller
bearing exposed to
vibration. The inner
ring has changed
position.

32. 32
CONCLUSION
My training at NATIONAL ENGINEERING INDUSTRIES, JAIPUR was very fruitful and I
gained a lot of practical knowledge about various manufacturing processes and techniques. I
also got the opportunity to realize the challenges faced and expertise required in
manufacturing processes for mass production.
It was indeed a great experience undergoing training at the plant.

33. 33