View
106
Download
15
Category
Tags:
Preview:
DESCRIPTION
MANUFACTURING OF BOLTS AND VARIOUS PROCESSES INVOLVED IN SAME.
Citation preview
INDUSTRIAL TRAINING REPORT
STERLING TOOLS LIMITED
DLF-5A
FARIDABAD, HARYANA
SUBMITTED BY:
PRINCE NASWA
BTECH MECHANICAL STUDENT
(ITM UNIVERSITY, GURGAON)
ROLL N0. : 12-MEU-067
1
ACKNOWLEDGEMENT
An undertaking of work life - this is never an outcome of a single person; rather it bears
the imprints of a number of people who directly or indirectly helped me in completing the
present study. I would be failing in my duties if I don't say a word of thanks to all those
who made my training period educative and pleasurable one. I am thankful to
STERLING TOOLS LIMITED, FARIDABAD for giving me an opportunity to do
summer training in the company.
First of all, I am extremely grateful to Mr. GAGAN JAIN (PRODUCTION
MANAGER) AND Mr. GAURAV for their guidance, encouragement and tutelage
during the course of the internship despite their extremely busy schedule. My very special
thanks to them for giving me the opportunity to do this project and for his support
throughout as a mentor .I must also thank my faculty guides Mr. ASHWINI SHARMA,
Mr. MOHIT DESWAL AND Ms. SHIKHA (Faculty, ITM
UNIVERSITY,GURGAON) for their continuous support, mellow criticism and able
directional guidance during the project. I would also like to thank all the respondents for
giving their precious time and relevant information and experience, I required, without
which the Project would have been incomplete. Finally I would like to thank all lecturers,
friends and my family for their kind support and to all who have directly or indirectly
helped me in preparing this project report. And at last I am thankful to all divine light and
my parents, who kept my motivation and zest for knowledge always high through the
tides of time.
2
ABSTRACT
This project dwells upon my project training at an esteemed NCR biggest Gasket
manufacturing organization, STERLING TOOLS LIMITED from 19.05.2014 to
1.07.2014. This training is a part of my course curriculum pursuing at ITM
UNIVERSITY, GURGAON.
In these 6 weeks I learnt the zest of the functioning of a manufacturing industry and how
the theoretical knowledge is applied in the working of the industry. I came to know about
the importance of safety of men, machine and equipment’s and the various steps that
need to be taken in this area to ensure their safety. I got an overview of each and every
department that works for making an industry a success, from R&D department to
packaging to dispatch department. I also learnt about the commitment of the company
towards quality of automobile products it produces and efforts made by all to ensure the
best quality of products.
It gives me immense pleasure to present this project report. The report commences with
company profile in which all the relevant details about sterling factory have been
included avoiding the secrecy norms of the company.
Learning in sterling was not limited to doing project only. I would like to say that my
experience in this factory would be unforgettable one throughout my life.
3
TABLE OF CONTENTS
1. COMPANY PROFILE………………………………………………………………...6
2. INTRODUCTION.………………………………………………………..………......16
2.1 TECHNICAL ASPECT………………………..…………………………………..17
2.2 RAW MATERIAL………………………………………………………………..18
3. FORGING……………………………………………………………………………..20
3.1 WIRE STRAIGHTENING.….…………………………………………………….21
3.2 TYPE OF HEADS…………………………………………………………………22
3.3 HEAD FORMATION……………………………………………………………...27
3.4 DEFECTS………………………………………………………………………….29
3.5 SAFETY EQUIPMENTS………………………………………………………….29
4. THREAD ROLLING………………………………………………………………….30
4.1 PROCESS ………………..………………………………………………………..31
4.2 DEFECTS……………………………………………….………………………....32
5. MACHINING PROCESS……………………………………………………………..34
6. HEAT TREATMENT……………….………………………………………………...41
6.1 PROCESS CONTROL PLAN……………………………………………………..42
6.2 DEFECTS………………………………………………………………………….48
7. SURFACE FINISHING……………………..………………………………………..49
7.1 PROCESS FLOW………………………………………………………………….50
4
7.2 PARAMETERS FOR QUALITY…………………………………………………55
7.3 CHEMICAL TEST’S…………………………………………………………...…56
7.4 DEFECTS………………………………………………………………………….57
8. LAB TEST’S……..…………………………………………………………………...58
5
COMPANY PROFILE
HISTORY:
Sterling tools limited (STL), is a well-established, dynamic and professionally managed
company, is a leading manufacturer of fasteners in India. The company was incorporated
as a private limited company in 1979 and was turned into a public limited company in
1994. In 1979 the company was incorporated as a private limited company on 7th June
and at that time the Company undertook to expand its production range from 16mm
diameter fasteners to 24 mm diameter fasteners. The Capacity was also increased to 230
million pieces from the existing 165 million pieces. In terms of tonnage, installed
capacity was increased to 7000 tons from 3200 tons.
This process of expansion carried on and company spent a huge amount on expansion
and quality aspect in 2005. Now Sterling tools is the third largest fastener manufacturing
company in India.
Today, STL is among the leading OEM suppliers in India serving the needs of leading
automotive companies in India, Europe and USA. A large part of this success can be
credited to our competent workforce that has helped us surpass new boundaries at every
step. It is through their contribution that we have been able to achieve our corporate
vision of “sustainable growth through overall excellence”.
The '360 degree' philosophy looks at all aspects of the company, from manufacturing and
quality control to human resource development as a tool to produce total customer
satisfaction. All around excellence for all around perfection…this is the promise of '360
degree' approach.
MANUFACTURING:
With the expertise of over two decades, STL manufacturing facility today includes state-
of-the-art annealing, cold forging, inline rolling, heat treatment, finishing/coating, CNC
turning, centre less grinding, circular thread rolling and other secondary operations.
In addition, company have also introduced a complete range of multi station headers with
automatic motorised adjustment systems that facilitate smooth and fast job changes.
6
Induction hardening of critical fasteners, use of sophisticated in-line hardening and
tempering furnaces with auto-load, pre-wash and post-washers, and the manufacture of
special fasteners with very close tolerance are key features of our manufacturing process.
STL finishing operations with hydrogen embrittlement facilities also include complete
waste treatment processes that bring us a step closer to an eco-friendly environment.
ENGINEERING:
STL's engineering department is led by a team of highly experienced leaders. Equipped
with the latest in CAD and simulation softwares and armed with the knowledge of an
extensive library, our engineering team is extremely competent, especially in the
manufacture of precision parts. Manufacturing feedback for improving the overall
machine effectiveness (O.E.E), APQP (Advanced Product Quality Planning) through
cross functional teams and in-house testing facilities like the SCHATZ torque testing
machine helps us understand and meet client needs consistently.
7
SURFACE TREATMENT AND COATING:
To meet the demands of a dynamic market environment, we offer Cr6+ free multi-colour,
micro-layer corrosion protection systems in accordance with strict environmental
regulations. Leading brands like Geomat™, Delatone™/Deltaseal™ and Dacromat™ are
used as coating finishes for our range of fasteners, as per the needs of leading
automotive/Tier-I players worldwide.
TESTING:
In order to ensure consistent quality of the final product, company have harnessed the
power of several high accuracy specialised instruments. These include the Contour graph,
Metrology-fisher scope, Tri-roll guages for thread checking, Torque wrench, Vicker
hardness tester, Eddy current tester, Spectrometer, Microscope (with image analyser),
Universal tensile machine and the Charpy tester. By identifying potential problems and
flaws early, we ensure that STL fasteners reduce operating and replacement costs and
ensure greater operating safety.
QUALITY:
STL’s focus on quality is evident from our attention to cellular manufacturing, operator
quality assurance and established traceability. In addition, STL’s NABL certified
laboratories equipped with various high accuracy specialised instruments ensure
8
unquestionable quality at every step. Little wonder then, that our manufacturing facilities
are all TS 16949 and ISO 14001 certified.
Quality Certifications:
ISO 14001:2004 Certification
ISO/TS-16949:2002 Certification
Testing Laboratory Certification by NABL
PRODUCTS:
Sterling tool manufacture a wide range of fasteners based on the following standards:
- Indian Standards-IS
- German Standards-DIN
- Japanese Standards-JIS
- American Standards-ASTM
- British Standards-BS
STL's product range encompasses a wide variety of standard, chassis, engine and special
fasteners.
Special Fasteners
Special fasteners are manufactured to suit unique customer specifications. Available in a
variety of surface protection coatings, these fasteners are proof of the fact that we provide
complete customizable solutions.
9
Standard Fasteners
Known for their excellence, our range of standard fasteners include socket head cap
screws, hexagonal head bolts, studs, hexagon nuts and weld nuts. The dual benefits of
better fatigue resistance and superior strength have made these fasteners a popular choice.
Chassis Fasteners
Our range of chassis fasteners include hub/wheel bolts, hub nuts, wheel studs, suspension
bolts, propeller shaft bolts/nuts, centre bolts, track shoe bolts/nuts, rivets and two wheeler
10
spindles/wheel axles. These are widely used in the undercarriage of automobiles and
heavy earth moving equipment’s.
Engine Fasteners
Engine fasteners include cylinder head bolts/screws, fly wheel nuts/bolts, connecting rod
bolts/nuts, balance weight bolts and main bearing cap bolts. These are widely used in
internal combustion engines.
Size Range:
Bolts and Screws
Size: M5 to M24 and equivalent inch series
Lengths: 8 mm to 250 mm
11
COSTUMERS:
The favoured supplier to all major OEMs in India, we at STL have used our experience
and understanding to serve the needs of market better. By providing full traceability from
quote to delivery and providing access to the STL product range in remote corners of the
Indian subcontinent through our well established dealer network, we have brought
ourselves closer to our customers. That's why leading automobile companies in India and
abroad have continued to place their trust in our product range.
DOMESTIC: AFTERMARKET
STL’s aftermarket network comprises more than 60 dealers and the numbers are growing
rapidly with every passing day. With regional offices in both Chennai and Pune and
residential representatives in places like Jamshedpur and Mumbai we have been able to
interact closely with automobile dealers, fleet owners and mechanics.
This has helped STL gain a better understanding of their needs and enabled us to serve
them better. By further strengthening our foothold in this segment, we intend to make our
presence felt in every part of the country.
12
Locations
Our Presence (India): Our Presence (Overseas)
Agra Bangladesh
Ahmedabad Detroit (USA)
Allahabad Nepal
Ambala Italy
Banglore
Chandigarh
Chennai
Cuttack
Ernakulam
Gandhinagar
Ghaziabad
Gorakhpur
Guwahati
Hyderabad
Indore
Jalandhar
Jammu
13
Jamshedpur
Kanpur
Kolkata
Lucknow
Ludhiana
Meerut
Mumbai
Nasik
Patna
Puna
Ranchi
Salem
Trivandrum
Varanasi
Vijaywada
Head Office: Faridabad
Registered Office: New Delhi
Plants:
1. Faridabad
2. Ballabhgarh
3. Prithla
4. Uttaranchal
Details of some of major customers and their contribution to revenue are as follows:
Maruti Udyog 14.97%
Tata Motors 14.90%
Mahindra & Mahindra 7.40%
Hero Honda Motors 10.38%
14
Honda Motorcycle & Scooters 7.14%
Ashok Leyland 7.00%
Bajaj auto 5.03%
Escorts 6.11%
Eicher 6.71%
Investor Relations
Sterling Tools Limited, (BSE: 530759, NSE: STERTOOLS), is engaged in the
manufacturing of high-tensile (HT) cold forged fasteners mainly for automobiles. The
Company is one of top 3 fasteners manufacturers in India and caters to leading
automotive companies in India, Europe and USA. STL has 3 plants which are located in
Faridabad and has over 900 employees. The product portfolio includes special fasteners,
standard fasteners, surface treatment and coatings, chassis fasteners and engine fasteners.
The objective of Sterling Tools Investor Relations is to ensure continuous and open
communication with all financial market participants.
15
INTRODUCTION
An industrial fastener comprises a very wide range of items like nuts and bolts, washers,
studs, nails etc. Nuts and bolts consist a major link in the family of industrial fasteners
and are used by every industry. Bolt is a piece of metal rod, whose one end is unsettled
and other end is threaded. Nut is the item, which rolls
on these threads. Nut and bolts are available in various shapes, designs and sizes.
Nuts and bolts are used for fastening purpose in industries where the replacement of
pieces and the parts is necessary. There are many industries producing these nuts and
bolts of various sizes, but the demand too is increasing as well as the raw material for the
product is easily and indigenously available. The main raw material is mild steel wire
coil/rod of required diameter. The composition of materials controls the quality of the
bolts and nuts.
The recommended composition for nuts and bolts raw material is given as under:
Carbon 0.22 to 0.23%
Phosphorus 0.40%
Manganese 0.39 to 0.60%
Sulphur 0.50%
Nuts and bolts are classified by two ways: i) Their uses, ii) Shape of head.
In terms of use, nuts and bolts are of several types:
Larger dia bolts, machine bolts, stand bolts, joint bolts, foundation bolts and nuts etc. in
terms of shape, bolt and nuts are classified by head shape like hexagonal head, square
head, round head, pan head, truss head etc.
MARKET POTENTIAL:
16
The demand of nuts and bolts is influenced by the following factors:
Transportation industries, Railways, aircraft, wagon, bicycles, automobile, body builders, etc.
Electrical industries like manufacturing of transformer, electric motors, fans etc.
Building activities such as construction of bridges, fabrication of various steel structures etc.
Other heavy and light industries, steel and wooden furniture, machine tools, Agricultural machines and agricultural implements etc.
As various types of MS and HT nuts and bolts are used in above sectors, the market
demand is directly proportionate to the development of these industrial segments.
TECHNICAL ASPECTS
Process of Manufacture:
The raw material used for manufacture of bolt is M.S. Rounds. As some of the rounds
available are rusty and not perfectly round and straight, it is necessary to make them
round. The rounds are pickled in the acid tanks, washed and drawn in a drawing machine.
The cleaned rod is fed into the cold heading machine. In the machine, one end of the rod
is cut into the desired length with cutting stroke and simultaneously the head formation
takes at another end. For the HT bolts, forging is done on hot forging press. The pins are
then trimmed in the trimming machine.
In quality bolts, the lower side of the head is also faced. Threading is done in the thread
rolling machines.
General Process Flow Chart
17
Mild steel rod
Bolt cutting
Head making
Head trimming
Thread rolling
Polishing
Store/dispatch
RAW MATERIAL
Quality of bolts depends on the composition of various elements in raw material.
According to the composition required there are total 17 grades of raw material available.
Grade is decided according to the costumer requirement.
Costumer gives the grade of raw material to be used or tells the composition of various
elements required in the product. For eg. Costumer gives the percentage of carbon,
boron , sulphur or other elements according to the requirement and then the most suitable
grade to the specified composition is used in manufacturing.
18
CHEMICAL COMPOSITION OF RAW MATERIAL
MATERIAL C Mn Si S P Cr B
1008 Min. 0.3
Max. 0.1 0.5 0.05 0.04
1010 0.08 0.3
0.13 0.6 0.05 0.04
1018 0.15 0.6
0.2 0.9 0.05 0.04
10B21 0.18 0.6 0.0008
0.23 0.9 0.3 0.025 0.025 0.003
10B21M 0.18 0.8 0.0008
0.23 1.1 0.3 0.025 0.025 0.003
10B35 0.32 0.7 0.15 0.1 0.0008
0.38 1 0.35 0.025 0.025 0.003
15B25 0.23 0.9
0.28 1.2 0.3 0.025 0.025 0.003
15B41 0.36 1.35 0.15
0.44 1.65 0.3 0.025 0.025 0.003
15B37 0.36 0.35 0.15 0.9 0.0008
0.42 0.50 0.3 0.025 0.025 1.15 0.003
1541 0.36 1.35 0.15
0.44 1.65 0.3 0.025 0.025
4135 0.33 0.7 0.15
0.38 0.9 0.3 0.025 0.025 1.1
4140 0.38 0.75 0.15 0.8
0.43 1 0.3 0.025 0.025 1.1
4137 0.35 0.7 0.15 0.8
0.4 0.9 0.3 0.025 0.025 1.1
19MnB4M
19
SCM 435
SCM 440
FORGING:
Forging is a process in which material is shaped by the application of localized
compressive forces exerted manually or with power hammers, presses or special forging
machines. The process may be carried out on materials in either hot or cold state.
Forging is an effective method of producing many useful shapes. Typical forged parts
include rivets, bolts, crane hooks, connecting rods, gears, turbine shafts, hand tools,
railroads, and a variety of structural components used to manufacture machinery.
The forged parts have good strength and toughness; they can be used reliably for highly
stressed and critical applications.
A variety of forging processes have been developed that can be used for either producing
a single piece or mass – produce hundreds of identical parts.
Hot forging is the plastic deformation of metal at a temperature and strain rate such that
recrystallization occurs simultaneously with deformation, thus avoiding strain hardening.
For this to occur, high work piece temperature (matching the metal's recrystallization
temperature) must be attained throughout the process. A form of hot forging is isothermal
forging, where materials and dies are heated to the same temperature.
Cold forging involves impression die forging or true closed die forging with lubricant
near room temperature. Carbon and standard alloy steel forgings are most commonly
cold-forged. Parts are generally symmetrical. The primary advantage is the material
savings achieved through precision shapes that require little finishing. Completely
contained impressions and extrusion-type metal flow yield draft less, close-tolerance
components. Production rates are very high with exceptional die life. While cold forging
usually improves mechanical properties, the improvement is not useful in many common
20
forging applications and economic advantages remain the primary interest. Tool design
and manufacture are critical.
Now the process of forging is given below:
WIRE STRAIGHTENING:
PROCESS OF STRAIGHTENING:
1. Feed the wire in the rollers.
2. Apply pressure and push wire ahead.
21
3. Check all the vertical rollers are aligned.
4. Check all the horizontal rollers are aligned.
5. After this check all the rollers are rolling properly or not.
After straightening the wire passes through the feed tube. The stopper stops wire at
particular length. A cutter is attached adjacent to stopper which cuts the wire in
desired length. Now, the wire is passed through a series of subsequent die to give it
desired shape.It passes through 4 set of die’s.
The above given is a forging machine and its inside parts are shown below called house.
22
This figure shows a wire stand on which wire is loaded and then straightened for forging
into bolts.
A forging machine consists of three basic parts:
1. CAM
It is the most important component for punching the bolt. It gives pressure and
timing of punch.
2. Transverse slide
It consists of rm, retainer, spring, gear and finger.
3. House
The wire passes through house and it consists of all other components.
TYPES OF HEAD’S
Shape of head is also given by costumer according to the type of product to be
manufactured. Normally, hex head bolts are major requirements of costumers as they
provide a good grip and a strong head.
23
There are 9 types of bolt heads. Given below:
1. Hex head screw
2. Hex head bolt
3. Flange bolt
24
4. Collar hex bolt
5. Stud
6. D Stud
25
7. T Stud
8. 12 point corner
9. Indent head
Bolt Size:
Eg: M12 X 1.75 X L HHS
Here,
M12 represents the diameter of bolt
26
1.75 is the pitch of bolt
L is length
HHS is the type of head
HEAD FORMATION:
Bolt head formation is a 4 station process.
1. Cut off
2. Cone formation
3. Heading
4. Final trimming
27
28
DEFECTS:
1. Burr on head piece.
2. Chip mark on monogram.
3. Chip mark on bearing face.
4. Short feed piece.
5. Burr under head piece.
SAFETY EQUIPMENTS:
1. Gloves
2. Helmet
3. Shoes
4. Mask
5. Glasses
6. Harness(if climbing)
7. Oxygen mask (for harmful gases)
8.
Bolt production rate varies from 60 to 100 bolts per minute for bolts having diameter 5 to
12 mm.
And for diameter 12 to 25mm production rate is 50 to 70 bolts per minute.
29
THREAD ROLLING:
Thread rolling is a metal rolling process used extensively in manufacturing industry to
produce screws, bolts and other fasteners. A common thread rolling process, used in
industry to manufacture threaded parts, involves forming the threads into the metal of a
blank by a pressing and rolling action between two die. The die surface hold the shape
and the force of action forms the threads into the material.
Thread rolling has an extremely high productivity rate, significantly higher than
producing threaded parts by machining. Machining is the alternative method to industrial
manufacturing of threaded parts. Producing threads by this method has several other
benefits over machining.
Benefits of thread rolling over machining:
1. Forming will harden the metal through cold working.
2. Does not waste material by cutting.
3. Produces a favorable grain structure.
For thread rolling a forged bolt is kept between a stationary and a moving die is allowed
to roll in between them. So, the threads are formed on bolt. And the bolt is ready for
further processes.
30
PROCESS:
31
DEFECTS:
1. DENT
2. THREAD DAMAGE
3. INCLINED THREAD
4. THREAD DIE MARK
5. BODY ROLLED
6. CHIPS
7. MATCHING CUT
8. THREAD GAP
9. FLAT THREAD
10. WITHOUT ROLLING
11. SETTING PIECE
12. DIE MARK ON FLANGE
32
Forging and thread rolling department is divided into two modules according to the size
of bolts.
In module 1 bolts of size 5mm to 12mm are forged and threaded. It consists of 11 forging
and 8 rolling machines. Whereas in module 2 bolts of size 12mm to 25mm are forged and
threaded. It consists of 7 forging, 6 rolling, 2 stud rolling and 1open die header machine.
33
MACHINING PROCESS:
Machining is a metal removal process in which excess material is removed to obtain
desired shape, size. Machining is done by using CNC machines which are highly efficient
as they are more accurate, less time consuming. So, more productivity and are cost
effective also.
Different operations performed on CNC for bolt machining are listed below:
1. Grooving
34
2. Parting
3. Turning
4. Facing
5. Boring
35
6. Threading
7. Bore in nut
External operations : 1. Parting off, 2. Grooving, 3. Turning, 4. Profiling,
5. Undercutting, 6. Face-grooving, 7. Threading
36
In parting operations, the objective is to separate, as efficiently and reliably as possible.
One part of the work piece from the other. A straight cut is made to a depth equalling the
work piece radius of a bar. In grooving operations, the principle is the same but with the
difference that the cut is shallower and not taken to the center.
Grooving operations are less sensitive in some respects because the grooves are usually
not as deep, instead shape, accuracy and surface finish are often demands that need more
attention.
The machining process can be compared to a facing operation in turning, where the tool
is fed radially into the center.
The difference being that in the parting operation, the tool is a thin blade making a
narrow groove. There is material on both sides of the tool and thus the material to be cut
through should be as little as possible and the width of the cutting edge should be small.
This makes considerable demands on the performance, chip forming and stability of the
parting tool.
As the tool moves to the center, and if the spindle speed is kept the same, the cutting
speed will gradually decrease until it reaches zero at the center. In CNC-lathes, the
spindle speed is increased as the tool moves towards the center. Any decrease in cutting
speed is disadvantageous for the tool and one that can make severe demands on the
cutting edge. As the edge approaches the center, pressure increases as the tool is fed in at
the decreasing cutting speed.
Cycle time varies for different product according to the operations performed.
Discontinuous chips are formed.
Tool life also varies with the type of product.
TOOLS USED ARE:
1. KVTL2525 Single point tool
2. SVJBL2525 M16 Single point tool
3. MTJNL 2525M16 Single point tool
37
4. SVHBL2525M16 Single point tool
5. SCLCL 06
6. BORING BAR To balance run out
INSERTS:
1. TNMG 160402MS
0.2mm insert, 6 point used for small diameter.
2. TNMG 160404
0.4mm insert 6 point
3. CCMT 060204FG
0.4 insert, used for boring tool.
38
4. VBMT160404MT
0.4 insert, 2point insert.
LUBRICANT:
Lubricant is essential part to run a machine to avoid friction between tool and work piece
which indeed increases tool life.
Cutting oil used in lubricant is Mobyl cut- 100.
Lubricant composition is 3 to 5% of cutting oil.
So, for 100lt CNC tank:
95lt. water + 5 lt. cutting oil.
DM water or RO water is used in lubricant.
Lubricant is changed after every 6 months. Concentration of lubricant is checked daily
using refractometer. Composition is also verified daily and accordingly oil or water is
added.
Lubricant tank is cleaned twice a week and all chips, trump oil is removed.
39
Ph is also checked daily using ph paper. Required ph for oil and water mixed is 8 to9 and
for DM water is 6 to7.
Instruments used for error measurement in machining:
1. Height gauge
2. Pappi dial
3. Dial gauge
4. Block
5. Gear gauge
Total 7 CNC manufactured by ACE designer and 19 threading machines are installed in
machining department.
After machining the bolt is sent for heat treatment.
40
HEAT TREATMENT
Heat Treatment is the controlled heating and cooling of metals to alter their physical and
mechanical properties without changing the product shape. Heat treatment is sometimes
done inadvertently due to manufacturing processes that either heat or cool the metal such
as welding or forming.
Heat Treatment is often associated with increasing the strength of material, but it can also
be used to alter certain manufacturability objectives such as improve machining, improve
formability, restore ductility after a cold working operation. Thus it is a very enabling
manufacturing process that can not only help other manufacturing process, but can also
improve product performance by increasing strength or other desirable characteristics.
41
PROCESS CONROL PLAN:
Loading: Free from size mix-up.
Free from thread damage.
Pre Washing: Free from oil.
Free from mix up.
Hardening, Quenching: Free from scaling.
Process:
1. Hardening temperature.
2. Conveyor speed.
3. Carbon potential.
4. Methanol flow rate.
5. LPG flow rate.
6. Mix fan running.
7. Uniform loading.
8. No products mix up.
9. Burnt time.
10. Quench oil temperature.
Post washing: Free from oil.
Tempering: Travelling time.
Zone temperature.
Unloading: Free from mix up.
Free from thread damage.
42
LOADER
OIL SKIMMER
(SPERATES OIL FROM MATERIAL)
WATER SUPPLY
(TO REMOVE LEFT OVER OIL)
HARDING CONVEYOR
(SPEED ACCORDING TO THE TIME SET)
QUENCH IN OIL
(TO PREVENT DECARB.)
CONVEYOR
OIL SKIMMER
TEMPERING FURNACE
(TO AVOID BRITTLENESS)
43
DYEING TANK
(WATER+CUTTING OIL, TO COOL DOWN)
UNLOADING
Gas flow meter is used to set LPG and Methanol concentration. There are 3 fully
automatic furnaces, temperature and other parameters are controlled by using computer.
HARDENING TEMPERATURE TABLE:
RAW MATERIAL HARDENING
TEMPERATURE ±10°C
CARBON POTENTIAL
±0.05
10B21/ 15B21
1541/15B41/ 4140
880 0.23
EN8/ 1045/ SCM440/ 4135/
10B35
860 0.36
1541 / 15B41 Carburizing temperature
900°c oil temperature 50 to
85°
0.8
MATERIAL GRADE TEMPERING TEMP. ±10°C
10B21 20/22 HRC
27/29HRC
515
460
44
15B25 / 19MnB4 30/33 HRC
7T,R
8.8, S
450
515
15B25 20/22 HRC 570
1541/15B41 21/23 HRC
8.8, 24/30 HRC
34/36 HRC
39/41 HRC
615
570
470
425
10B35 8.8, S
10.9
39/42
530
445
420
En8D 28/32 HRC 565
1045 28/35 HRC 545
4140, SCM 440 7T,R
8.8, 24/30 HRC
29/31 HRC
34/36 HRC
42/44 HRC
45/52 HRC
645
615
585
535
380
350
S70C 40/48 HRC 400
SIZE SPEED/SOAKING MIN.
(HARDENING)
SPPED/SOAKING
MIN.(TEMPERING)
M5,M6 & ¼” 70 75
M8, M7 & 5/6” 70 75
M9, M10 & 3/8” 75 80
M11, M12, 7/16”, ½” 75 80
M14 80 85
45
M16 & 5/8” 85 90
M18 85 90
M20, M22 , 7/8”, ¾” 90 95
M24& 1” 95 100
QUENCHED HARDNESS:
MATERIAL HARDNESS(HRC) AS QUENCHED
MINIMUM MAXIMUM
10B21/ 10B21M 38 HRC 44 HRC
15B25 40 HRC 46 HRC
15B41/1541 50 HRC 56 HRC
4140/ 4135 50 HRC 56 HRC
1045/EN8D 47 HRC 54 HRC
10B35 47 HRC 54 HRC
GRADE HARDNESS(HRC)
7T,R 20 TO28
8T/8.8 , S 22 TO 32
9T/9.8 , T 28 TO 34
10T/10.9, V 32 TO 39
11T, W 34 TO 39
12.9, X 38 TO 44
PROCEDURE OF WARMING UP:
1. Turn ON all cooling water switches and supply the cooling water.
2. Start up the main power and control panel power.
3. Set the temperature controller.
4. Start up the mixed fan.
46
5. Start up the heater switch and start heating.
6. Start up the transmission motor and start conveyor.
TEMPERATURE MAINTAINING:
1. The procedure of the first time warming up after long term off.
200 °c = 18 HRC ® 400°C=6 HR
2. Turning off the furnace for short term (2-5 days) need not require maintaining
procedure.
SHUTTING DOWN THE FURNACE:
1. Switch off the front washing tank heater after complete of the washing operator.
2. Confirm all the material has come out of the hardening furnace.
3. Stop heating, decrease the temperature and off the heating power.
4. Switch off the rear washing tank heater after complete of washing operation.
5. Turn off mixed fan when temperature reduces below 200°C.
6. As the furnace temperature lowers to 100°C or less, stop the cooling water supply.
7. Shut down the main power.
LPG AND METHANOL COMPOSITION:
Ensure minimum 100KGs stock of methanol and LPG. This prevents the entrance of
oxygen and maintains appropriate carbon content.
10B21 / 15B25 : 1500cc/hr. methanol
0.3 LPG in mm³/hr.
1541/4140 and all other grades : 2000cc/hr. methanol
0.3 mm³/hr. LPG.
DEFECTS:
47
1. High hardness after tempering.
2. Low hardness after tempering.
3. Low as quench hardness.
4. Tempered microstructure.
EVALUATION:
Check grain growth and decarb in material.
SURFACE FINISHING
48
ELCTROPLATING PROCESS FLOW:
Electroplating is the application of a metal coating to a metallic or other conducting
surface by an electrochemical process. The article to be plated (the work) is made the
cathode (negative electrode) of an electrolysis cell through which a direct electric current
is passesd. The article is immersed in an aqueous solution (the bath) containing the
required metal in an oxidised form, either as an aquated cation or as a complex ion. The
anode is usually a bar of the metal being plated. During electrolysis metal is deposited on
to the work and metal from the bar dissolves:
at cathode Mz+(aq) + ze-→ M(s)
at anode M(s) → Mz+(aq) + ze-
Faraday's laws of electrolysis govern the amount of metal deposited.
Articles are electroplated to
(i) Alter their appearance
(ii) To provide a protective coating
(iii) To give the article special surface properties
(iv) To give the article engineering or mechanical properties.
Most electroplating coatings fall into one of the following six categories:
1. Sacrificial coatings, used primarily for protection of the basis metal, usually iron and
steel (sometimes call anodic coatings, meaning that electrochemically they are anodic to
the substrate). Sacrificial denotes that the coatings "sacrifice" themselves in the act of
protecting the basis metal.
2. Decorative protective coatings, used primarily for adding attractive appearance to
some protective qualities.
49
3 Engineering coatings - a rather miscellaneous group whose members are used for
specific properties imparted to the surface, such as solderability, wear resistance,
reflectivity, conductivity, and many others. They are sometimes called functional
coatings, though it would seem that protection is also a "function".
4. Minor metals - a small group of metals that are easily plated but have rather limited
application.
5. "Unusual" metals - rarely electroplated, and when they are, they require special
conditions, such as non-aqueous solutions.
6 Alloys - an almost unlimited number of alloys has been plated experimentally, since the
possible combinations of the plateable metals, in various proportions, are in numerable.
Only a few have attained commercial importance.
PROCESS FLOW:
PRE- TREATMENT
LOADING
SOAK DEGREASING
(TO REMOVE OIL, GREASE)
ANODIC CLEANING 1
(CLEANING USING CURRENT)
CASCADE RINSE
50
(TO REMOVE CHEMICAL)
PICKILING
(REMOVE OXIDES)
CASCADE RINSE
ANODIC CLEANING 2
(TO REMOVE HARD SCALE)
CASCADE RINSE
ALKALI DIP
(TO MAKE SURFACE ALKALINE BASE)
PLATING
ALKALINE ZINC
CASCADE RINSE
UNLOAD TO BASKET
51
POST PLATING/ PASSIVATION LINE
PICK BASKET USING TRANSPORTER
BRIGHT DIP
(FOR SHINE)
RINSE
PASSIVATION
(TRIVALENT BLUE/ YELLOW OR HEXAVALENT YELLOW)
CASCADE RINSE
FINAL RINSE
DEHYDRATION
HOT AIR DRYER
(TO REMOVE WATER & CHEMICALS)
52
FINAL UNLOAD
DETAILED PARAMETERS
1. Loading
2. Hot degreasing 1
(Super soak - 50±5 G/lt.)
Temperature- 60 ± 5°C
Density- 6 ± 3 Be
Time- 8 ± 2 min
3. Electro degreasing 1
(Sterioclean-s-55 - 50 ± 5 g/lt. )
Temperature- 60 ± 5 °C
Density – 6 ± 3 Be
Time – 4 ± 2 min
C.D – 0.3-0.6 amp. /DM²
4. Acid pickling
(Commercial HCl – 200 ± 25 g/lt.)
Temperature – 35 ± 15 °C
Density – 18 ± 7 Be
Time – 7 ± 2 min
5. Electro degreasing
(sterioclean s-55 – 60 ±5 g/lt.)
Temperature – 60 ± 5 °C
Time – 4 ± 2 min
Density – 6 ± 3°Be
C.D – 0.3 to 0.6 amp./ DM²
53
6. Alkaline zinc plating
(caustic soda – 130 ± 10 g/lt.)
(zinc metal – 10 ± 2 g/lt.)
Temperature – 25 ± 5 °C
Density – 20 ± 2 ° Be
Time – 80 ± 25 min
C.D – 0.4-0.9 amp./dm²
Voltage - 8±4 volt
7. Drag out tank.
8. Triple rinse tank
9. Unload.
PASSIVATION LINE:
1. Bright dip:
(Nitric acid – 20 ± 5 pointage)
Time – 11 ± 2 sec
Dosing – 22 ± 8 ml/lot
2. Trivalent silver white:
(Tridurmax BL-Cr³⁺ 3.0±0.5 g/lt)
Temperature – 42 ± 2°C
Ph – 2.8 ± 0.2
Time – 45 ± 15 sec
Dosing – 160 ± 20 ml/lot
3. Trivalent yellow:
(Tridurmax - Cr³⁺ 2.8 ± 0.3 g/lt)
(Yellow additive – 0.1 ml/lt)
54
Temperature – 40 ± 2 °C
Ph – 1.6 ± 0.2
Time – 45 ± 15 sec
Dosing – 150 ± 20 ml/lot
4. Centrifugal dryer:
Temperature – 75 ± 25 ° C
Time – 6 ± 2 min
PARAMETER FOR QUALITY:
PROCESS PARAMETER
Hot degreasing 1. Temperature
2. Density
Electro degreasing 1. Temperature
2. Density
Alkaline zinc 1. Temperature
2. Zinc metal
3. Current
Passivation 1. Temperature
2. Ph
3. Cr³⁺
Top coat 1. Ph
Drying 1. Temperature
CHEMICAL TESTS:
a) Trivalent and hexavalent passivation confirmation.
b) Analysis of stiroclean s 55 in stiroclean s55 bath solution.
55
c) Analysis of HCl (36%) concentration.
d) Analysis of super soak concentration in super soak bath solution.
e) Analysis of nitric acid (69%) concentration.
f) Analysis of Zn, NaOH and Na₂CO₃.
SST PARAMETERS (SALT SRAY TREATMENT):
Chamber temperature: 33.3-36.1 °C
Fog collection: 1-2 ml/Hr.
Air pressure: 10-25 psi
Solution Ph: 6.5-7.2
Solution specific gravity: 1.0255-1.04
DEFECTS:
1. Colour variation.
56
2. Plating peels off.
3. Dull in thread.
4. Thread melting.
5. Excess/ low plating thickness.
6. Pitting.
7. No plating.
8. White rust formation.
9. Red rust observation.
10. Overall dull
After electroplating the samples are taken from each lot for lab tests.
LAB TESTS:
Samples are taken after each department for lab tests.
57
Lab test instruments:
Rockwell hardness tester (digital)
For hard material C scale is used. Load 150kgf. Unit HRC.
For soft material B scale is used. Load 100kgF. Unit HRB.
For even soft materials A scale is used. Load 60 kgf. Unit HRA.
Optical emission spectrometer:
To check chemical composition of raw material.
Fischer scope:
58
It is a measuring instrument for manual or automated coating thickness
measurements on functional coatings, corrosion protection coatings and mass-
produced parts.
Typical fields of application
Measurements of mass-produced electroplated parts
Corrosion protection and decorative coatings such as chrome on nickel/copper
Bath analysis in the electroplating industry
Gold, jewellery and watch industries
It is used to check plating thickness.
Error ±5%
Micro Vickers hardness tester:
Unit H.V. This is used for more accuracy. Can be used for weight material even
200gm.
Stereo microscope:
59
The stereo or stereoscopic or dissecting microscope is an optical microscope
variant designed for low magnification observation of a sample, typically using
light reflected from the surface of an object rather than transmitted through it.
The stereo microscope is often used to study the surfaces of solid specimens i.e. to
check surface discontinuity of product.
Carl zeiss microscope:
Microstructure decarbonization thread lock.
Brinnel hardness tester:
60
For checking more area, more load.
Load 300 kg.
Torque wrench bench:
For torque testing.
After lab tests are passed the product is sent for packaging and then dispatch.
61
CONCLUSION
It was really a wonderful experience to work as an intern in STERLING TOOLS
LIMITED, FARIDABAD. I gained a lot of insight regarding almost every aspect of the
industry. I was given exposure in almost all the departments at the industry. The friendly
welcome from all the employees is appreciating, sharing their experience and giving their
peace of wisdom which they gained in long journey of work. I came to know about how
the theoretical knowledge is to be converted into practical knowledge at various stages of
production of a particular product, in my case it was the production of bolts.
I learnt about the different processes used in making a bolt, from designing of a bolt to
the inspection of quality of bolt. I observed different machines and suggested ways on
how to improve it to accelerate the production. I also learnt about the technical
specifications of the different machines. Also, I learnt about the usage and importance of
various calibrating instruments at the CALIBRATION DEPTT.
My work in forging shop was really a fantastic one. Here apart from gaining technical
knowledge I came to know about various problems faced by the workers in the working
area. I even gave them suggestions on how to remove such a problem. Hope it will
contribute towards easing the life of a worker in the working area.
All in all this experience gave me the zest of how a manufacturing industry works. I hope
this experience will surely help me in the future and also in shaping my career.
62
BIBLIOGRAPHY
1. STERLING WEBSITE (www.stlfastenerscom)
2. WIKIPEDIA
3. WWW.TOOLINGU.COM
4. MAGAZINES (AUTOMOTIVE PARTS)
5. GOOGLE IMAGES
63
Recommended