NBC Jaipur Summer training report

1. Chapter 1
Introduction
1.1. Company profile
The 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
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2. 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.
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3. 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 Customers
Rolling 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.
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4. 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
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5. 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) PlantEstablished 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 & postprocess 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.
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6. Fig1.2: Newai (Gunsi) plant
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.
Fig1.3: Manesar Plant
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7. Chapter 2
NBC Jaipur
2.1. Introduction
This 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. The plant at
Jaipur includesi.
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 BearingThe 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
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8. Radial ball bearing
Angular Contact Bearing
Self-Aligning Two-Row
Ball Bearing
(a)
(b)
(c)
Fig. 2.1 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, selfaligning 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
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9. 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. 2.2 Steel Balls
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10. 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
(a)
Double Row Tapered
Roller Bearing
(b)
Fig 2.3 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
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11. 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 modernisation 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 bearing
Railway 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 boxes
Fig 2.4 Axle Boxes
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.
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12. 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 Railway The development of completely indigenise axle boxes and
bearings for the high speed Rajdhani Locomotive and the Yogoslavia and Egyptian
Railway Wagons are the highlights of the design capabilities at NEI.
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 bearing
The 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
Cartridge Tapered Roller Bearing
Spherical Roller Bearing
(a)
Fig 2.5 Railway Bearings
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(b)

13. 2.5.3. Cartridge tapered roller bearing
For 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 indigenise 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 1.2acres.
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 and
furnaces 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 development
Complete 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
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14. centre. 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 building
The 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-ERP
In order to re-engineer and integrate the Business processes for Sales, Production,
Materials and Finance, NEI has success- fully implemented SAP ERP. By use of
this Package, our processes now conform to World Class best practices.
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15. Chapter 3
Railway Bearing Department
(Spherical Roller Bearing)
3.1. Introduction
I did my training at Railway Baring Department (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 Bearing
A 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
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16. 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 materials.
The 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
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17. 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 cages
As railway bearing is included in three sections
Roller Bearing & Axle Boxes
Spherical Roller Bearing
Cartridge Tapered Roller Bearing.
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18. A spherical roller bearing contains the following partsMain 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.
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19. 3.4 Raw material suppliers
These are the industries which supply the forged raw material to NBCa) 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
inspectsa) 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 ringa) 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 ring19 | P a g e

20. a) Width size
b) Bore
c) Undercut size
d) Oil groove size
e) Surface defects
f) OD size
g) For SEMI-FINISH/FINISH ROLLERa) 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 RETAINERa) 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
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21. 3.5. 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: 3.2 Flow diagram of material flow in industry
Before going to discuss various dept. in railway division we will go through the
bearing material, which we are using in NBC.
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22. 3.6. 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 and
(vi) Stress reliving.
Figure: 3.3 Heat treatment sequence
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23. Let’s discusses each process with respect to these parts for simplicity of
understanding
Fig: 3.4 Flow diagram of heating sequence of spherical bearings
3.7. 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.
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24. 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 3.5 Rotary hearth furnace
3.8. 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.
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25. 3.9. QuenchingQuenching 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
250C. 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.
3.10 TamperingMartensite 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.
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26. Fig :3.6 Tempering furnace
3.11. 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 causes26 | P a g e

27. a) Manufacturing Fault
b) Furnace temperature fault
c) Tampering fault
Fig: 3.7 Rockwell hardness test setup
3.12. 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
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28. in N.E.I. Ltd. HOCUT B-60 oil is used.
The objectives of cooling is arei.
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.
3.12.1 Operational step to grind Inner race:
Fig3.8: process sequence
(a) O.D. grindingOD 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 grinding28 | P a g e

29. 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 grindingThe 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)
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30. 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.
3.12.2. Operation steps to outer race grinding
Fig: 13.9 Process sequences for outer race grinding
(a) Face grindingFacing 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 grindingTrack is the path on which rollers will move so track of the cup should be
grinded properly. So that rollers will move smoothly.
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31. Fig: 3.10 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.
3.12.3 Operational step in grinding of roller
Fig: 3.11 Rollers of spherical bearing
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32. Face Grinding
Body Grinding
Fig: 3.12 Process sequence for grinding of rollers
(a) Face GrindingThe face grinding is done after centerless grinding of rollers. Specially
made machines used for face grinding.
Fig: 3.13 Face grinding of roller
(b) Body GrindingBody grinding of spherical rollers is done by specific grinding wheels made for ths
operation.
Fig: 3.14 Body grinding of rollers
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33. (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: 3.15 Roller super finishing
3.13. 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.
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34. Fig 3.16 Elements after assembly of spherical bearings
3.14. Maintenance and inspection section
3.14.1 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,
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35. vi.
MILLING m/c,
vii.
Universal type,
viii.
Vertical and Common type, Plain Milling m/c
3.14.2. 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
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36. Chapter 4
Learning and Suggestions
4.1. LearningThis training is very fruitful to me. I got immense knowledge of the industry
environment as I worked in the Taper Roller Bearing department. Besides that
outcomes of the training are pointed out beneath-
4.1.1. Effect of quenching mediumWe are using oil in quenching process but we can also use water, Brine solution or
air for quenching purpose. As we know that water has high thermal conductivity
and air has the least. So if we use water then cooling of the austenite steel will be
very fast and due to this crack will be formed on the surface of the steel or
material. If we use air that it will not remove the heat fast because it has low
thermal conductivity and it will not serve the purpose.
4.1.2. Rockwell hardness test processBefore and after tampering to check the difference in hardness of bearing races that
comes in tampering process Rockwell Hardness Test is being used. The following
steps are to check the hardnessTable:4.1 According to material/job, we select the load indenter and scaleMaterial
Load
Indenter
Scale
Hard job
150 kg
Diamond
C (Blake)
Soft job
100 kg
Ball (HCS)
B (Red)
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37. 1. Set the polished job (by Mb paper) and apply the load by hand lever
2. Hold the load for 10 seconds
3. Release the lever and note the scale reading
Note: The range of hardening of standard piece should lies between +1.5 to 1.5
4.1.3 Why material is demagnetized in Assembly section?
As we have noticed that material is demagnetized in the assembly section because
bearings will be set at a place where they will rotate and we know if a magnet will
rotate then it will produce electric field. So it may hamper the other activities of the
system. In machines it will tend to attract the machine parts.
4.1.4 How wastage reduced?
To reduce the wastage NBC come on a solution with the help of NTN Corporation.
They recognized six type of waste(a) Over ProductionThey produce according to demand of customers.
It helps to reduce the waste & scrape.
(b)WaitingProcess which takes maximum time, identify that process (bottle neck process) and
try to reduce the process time to reduce the idle time of other processes which
depends on that.
(c)Transportation-
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38. Try to minimize the distance between raw material and distance. This will save the
worker’s time and money and productivity will be increased. To do this a new
process can be stabilized or we can change the layout.
(d)InventoryRaw material should not be more than the demand. This stops the money in terms
of inventory.
(e)MotionCause of this- not placing tools at their proper place, it effects the motion of
worker. So there is loss of worker time and loss of machine production. For this we
should apply the work standard and design the work table according to need.
(f)Re-workCause- if product is not in proper size than there is need to again work on that. This
effects the loss of money, loss of worker and loss in production. For this we need
to understand the root of problem and try to make product correct in first time.
4.2 Flaking of rollers
Fig:4.1 Flaking of rollers
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39. Table:4.2 Causes and corrective of flaking
Causes
Corrective
Excessive loads, fatigue life, improper
handling
Improper mounting
Insufficient precision of journal or
housing
Insufficient clearance
Contamination, Rusting
Find the cause of heavy, load
Softening due to abnormal temperature
rise
Check internal clearance, regularly
Improve precision of journal and
housing
Improve operating conditions
Improve method of assembly and
handling
Check grease and greasing method
4.3 Comparisons between NBC Bearing and Bajaj BearingTable:4.3 Comparison between NBC Bearing and Bajaj Bearing
Type
Stake
NBC Bearing
11%
Bajaj Bearing
3.7%
Turnover(2012-13)
Rs. 1326 crores
Rs. 204 crores
Quantity
Range
45.6 Million Bearings per
annum
6mm bore to 1300 mmOD
7.592 Million Bearings per
annum
11mm bore to 95mm OD
Quality(Rejection)
1 PPM
6PPM
Customers
More than 34 big industries 12 industries in India and 21
and 21 countries
other countries
The comparison between NBC Bearing and Bajaj Bearing show that NBC bearings
is better than Bajaj Bearings in quantity wise and quality wise.
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40. Chapter 5
Conclusion and Discussion
5.1. Training experience
My training period of 45 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.
5.2. About report
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.
5.3 Conclusion
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 bearings mfg. co.
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41. How an Industry works.
Learning of practical aspects of various dept. (Heat treatment, Grinding) in
railway bearings.
Got a brief idea about various heat treatment processes along-with their
industrial use.
Working of conventional machining process (grinding).
Industrial applications of all types of grinding and finishing processes.
Use of various gauges along-with applications of dial indicators in gauges.
How all the maintenance and inspections is done on in line processing or
after processing.
Various techniques of inspection methods.
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42. REFERENCES
BHANDARI V.B., Rolling Contact Bearing, Tata McGraw Hill
Education Private Limited, Fifth Reprint 2011.
RAO P.N, volume 2, Abrasive Processes, Tata McGraw Hill Education
Private Limited, Tenth Reprint 2011.
RAO P.N, volume 1, Engineering Materials, Tata McGraw Hill
Education Private Limited, Second Reprint 2009.
RAJVANSHI A.K., Manufacturing Processes, Genius Publications.
http://www.nbcbearings.in/nbcpdf/Spherical_Roller_Bearings_catalatue_Fi
na.pdf, on 15/06/2013
http://www.nbcbearings.in/nbcpdf/TechnicalCatalogue2012.pdf, on
15/06/2013
http://www.nbcbearings.in/nbcpdf/CTRBM.PDF, on 15/06/2013
http://www.nbcbearings.in/nbcpdf/SRBMM.PDF, on 15/06/2013
http://smartinvestor.business
standard.com/BSCMS/PDF/SKF_20080703.pdf
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