1. NAME : - Ayush Kumar Saxena
Univ.roll no. : - 131300104009
Academic session : - 2013-2017
DEV BHOOMI INSTITUTE OF TECHNOLOGY
AND ENGINEERING.
DEHRADUN (UTTRAKHAND)
DEPARTMENT OF MECHANICAL ENGINEERING.
2. CONTENT
AKNOWLEDGEMENT………………………………………………….3
HISTORY OF THE COMPANY……………………………………….4-5
Company profile…………………………………………………………..6
VISION OF THE COMPANY……………………………………………7
POLICIES OF THE COMPANY……………………..........................8-9
LIST OF DEPARTMENT VISITED IN TRAINING………………..10
SAFETY DEPARTMENT…………………………………………....11-12
PICKLING DEPARTMENT…………………………………………13-14
ROLLING MILL DEPARTMENT…………………………………15-16
ECL DEPEARTMENT……………………………………………..17-19
ANNEALING DEPARTMENT……………………………………....19-22
SKIN PASS MILL…………………………………………………….23-26
QUALITY SYSYTEM……………………………………………....27-28
3. AKNOWLEDGEMENT
The internship opportunity I had with [BHUSHAN STEEL
LIMITED] was a great chance for learning and professional
development. Therefore, I consider myself as a very lucky
individual as I was provided with an opportunity to be a part of it. I
am also grateful for having a chance to meet so many wonderful
people and professionals who led me though this internship period.
Bearing in mind previous I am using this opportunity to express
my deepest gratitude and special thanks to the MD of [BHUSHAN
STEEL LIMITED] who in spite of being extraordinarily busy
with her/his duties, took time out to hear, guide and keep me on the
correct path and allowing me to carry out my project at their
esteemed organization and extending during the training.
I express my deepest thanks to Mr. S.K.GUPTA, Gernal
Manager (HR&ADMN.) for taking part in useful decision &
giving necessary advices and guidance and arranged all facilities to
make life easier. I choose this moment to acknowledge his/her
contribution gratefully.
I perceive as this opportunity as a big milestone in my career
development. I will strive to use gained skills and knowledge in the
best possible way, and I will continue to work on their
improvement, in order to attain desired career objectives. Hope to
continue cooperation with all of you in the future,
Sincerely,
Ayush Kumar Saxena
4. HISTORY OF THE COMPANY
Year events 1983- The Company was incorporated on
7thJanuary, under the name of Jawahar Metal Industries Private
Limited for the manufacture of cold rolled steel strips and steel
ingots at Sahibabad Industrial Area, District Ghaziabad.
Bhushan Steel (BSL), earlier known as Bhushan Steel & Strips
was incorporated in the year 1983.It is a globally renowned
company and is one of the leading prominent players in Steel
Industry. Backed by more than two decades, of experience in Steel
making, Bhushan Steel is now India 3rd largest Secondary Steel
Producer Company with an existing steel production capacity of 2
million tones per annum.
The company has three manufacturing units in the state of Uttar
Pradesh (Sahibabad Unit), Maharashtra (Khopoli unit), and Orissa
Plant (Meramandali unit) in India and sales network is across many
countries. The company is a source for vivid variety of products
such as Cold Rolled Closed Annealed, Galvanized Coil and Sheet,
High Tensile Steel Strapping, Colour Coated Coils, Galume Sheets
and Coils, Hardened & Tempered Steel Strips, Billets, Sponge
Iron, Precision Tubes and Wire Rod..
BSL clientele includes automobile and home appliances majors
like General Motor, Hyundai Motors, Ford Motors, Mahindra &
Mahindra, Eicher Tractors, Ashok Leyland, LG Electronics,
Whirlpool, Videocon, Daikin, Samsung Electronics, Godrej,
Voltas, IFB, Carrier Refrigeration, Electrolux Group amongst
others.The company is on due course o become a fully Integrated
Steel & Power Company with market leading offerings in value
added Steel in Automotive and White Good Segment with the
quality been approved by ISO 9002 and QS 9000.v
5. Recognition:
BSL has received ISO 14001:2004 certification for Environmental
Management System.
BSL has received ISO/TS 16949:2002 certification for Quality
Systems
Milestone:
Most brilliant milestone in BSl journey of excellence is setting up
of Steel and Power Plant in Orissa. On completion, the Plant will
be one of the largest integrated Hot Rolled Steel and Power
complexes of the nation.
BSL has emerged as the countries largest and the only CR Steel
Plant with an independent line for manufacturing Cold Rolled
Coils and Sheets up to a width of 1700mm, as well as Galvanized
Steel Coils and Sheets up to width of 1350mm.
Bhushan Steel has transformed to 3rd largest producer of Cold
Rolled Steel with an installed capacity of one million tons and
sales of more than USD 1 Billion.
Focused on niche high value added segment of automobile and
white goods, the company today is a leader in these segments.
The company is first to set up a high Tech Plant in 1996 to cater to
auto mobile and white good sector, in technical tie up with
Sumitomo Metals, Japan.
Finally, the company is profit making and paying dividend since
its inception.
6. COMPANY PROFILE
Date of Establishment : - 07-01 1983
Revenue : - 1676.87 (USD in Millions)
Market Cap : - 8437.6450845 (Rs. in Millions)
Corporate Address : - Office No. 33, Basement,
Mona Shopping Centre, J.P
Road, Near Navrang Cinema
Andheri (West)Mumbai
400058, Maharashtra.
www.bhushansteel.com
Management Details
Chairperson - Brij Bhushan Singal
MD - Neeraj Singal
Directors - Vipin Anand, Rahul Sengupta, Rajesh
Yaduvanshi, A K Deb, Kapil Vaish, Pankaj Sharma, Sahil
Goyal , Pradeep Patni, Rakesh Singhal, Ashwani Kumar, M
V Surya Narayana, BB Tandon, P K Aggarwal, Nittin Johari.
Business Operation : - Steel & Iron Products
Financials: - Total Income - Rs. 106592.778 Million (year ending
Mar 2015)
Net Profit - Rs. -12538.28 Million (year ending Mar 2015)
Auditors- Mehra Goel & Co, Mehrotra & Mehrotra
VISION OF THE COMPANY
7. The key to Vision is to use rigorous conceptual framework and to
understand how that framework connects to the underlying DNA
of enduring great companies.
A well-conceived vision consists of two major components
—"CORE IDEOLOGY" and an "ENVISIONED FUTURE". A
good vision builds on the interplay between these two
complementary Yin-and-Yang forces; it defines "What we stand
for and Why we exist" that does not change the Core Ideology and
sets forth "What we aspire to become, to achieve.
It is true to say that most of our vision statements express an
element of ambition.BSL's vision of total integration is a lot closer
to realization today. Through seamless backward integration, BSL
is consolidating its position on the entire steel value chain from
iron ore to spedalized is surging ahead.
8. POLICIES OF THE COMPANY
Bhushan Steel is leading the technological revolution in Indian Cold Rolled
Steel Industry today and defining new frontier of customer satisfaction. Be it
through technology and product upgrades, R&D efforts or stringent quality
control measures, company is consistent in its pursuit of value.
Bhushan Steel has earned a Quality Standards by getting many
Certifications.
QUALITY POLICY
BHUSHAN STEEL LIMITED aspires to make the difference in Steel
Industry by becoming the most favoured Supplier, producing the wide range
of premium quality products by adopting the latest technology, processes
and equipments. We are committed to provide value to our customers by
providing the best of products and services through enhanced customer co-
ordination, better team work and continual improvement of products,
technology, and manpower and capability enhancement.
SAFTY AND HEALTH POLICY
BHUSHAN STEEL LIMITED hicanundali Ohrnkanil SAFETY &
HEALTH POLICY Bhushan Steel limited is committed to provide Safe &
Healthy work environment to its workmen through adoption of best
technology and sound operating practices.
9. HR POLICY
Bhushan Steel recognizes that its Human Capital is an important source of
its competitiveness.
It will pursue management practices designed to foster meritocracy.
Bhushan Steel shall strive to attract best available talent ensuring a diverse
workforce.
ENVIRONMENTAL POLICY
Bhushan Steel Limited Is committed to protect environment by-
Ensuring continual improvement in environmental -.7 performance.
Complying with applicable environmental legislations and regulations.
Setting time bound environmental objectives to control various kind of
environmental pollution like air, water, noise and solid waste etc.
Conserving resources like fuels, raw materials, water and energy.
Developing green areas in and around the plant.
Communicating the policy to all employees and making them
environmental aware workforce.
Displaying the policy and making it available to the public on demand.
Reviewing the policy once in a year or whenever there Is any change in
operations to verify its suitability.
10. LIST OF DEPARTMENT VISITED IN
TRAINING
S.NO Department HOD
1 Safety Mr. Sudhir Kumar
2 Pickling Mr. LR Singh
3 Rolling Mill Mr.Neeraj Sharma
4 ECL Mr. Manish sirsikar
5 Annealing Mr.Neeraj Gupta
6 Skin pass mill Mr.Satyaveer
7 Finishing Mr. AK Kansal
8 Quality System Mr. Deepak Agarwal
9 GP-1 Mr. R C Singh
10 Utility Mr. AK gupta
11 Mechanical maintenance Mr.Amit Sharma
12 Narrow Plant Mr.Sarvesh
13 Electrical maintenance Mr. Rajesh Gupta
11. SAFETY DEPARTMENT
Bhushan Steel is committed towards a safer and healthier work
environment. For safety measures training we have a dedicated
audio-video centre at all our plants. Every worker is provided with
proper first-in-class safety equipment making it safe for them to
undertake different tasks throughout the day. Mock drills and
seminars that are conducted on a monthly basis also help in cross-
checking the safety knowledge and awareness amongst the
workers, and bridge any communication gap that might exist
between the workers and our safety department. Regular health
check-ups are done at the plant, with compulsory participation for
all workers to make certain that their health is not being
compromised in anyway.
Everyone entering the plant has to go through a safety training
program, in which we teach them all the basic measures that one
needs to follow in case of emergencies and in general. The task
here is to inform, educate and train employees and visitors in the
vicinity of the plant about the hazards and preventive measures. A
specifically shot safety video gives a proper demonstration of how
different safety measures are being undertaken at Bhushan Steel.
Mock drills are conducted every month with four mock drills
witnessed by the respective district authorities every year.
12. With an extensive safety and health policy in place, a
comprehensive system is built around the framework of the plants
to manage safety measures of the highest order. It involves daily
rounds by HODs of every department, appointment of safety
captains, officers and internal as well as external safety audits to
look into preventive and safety measures for the plant. A unique
safety rewards and penalty program has been introduced with
regular inspections and checks.
At our Odisha plant we also have a 6-bedded Occupational Health
Center that stands in service with two 24-hours in-house doctors,
adequate medical staff and ambulance.
………
PICKLING DEPARTMENT
13. Pickling (metal)
Pickling is a metal surface treatment used to remove impurities,
such as stains, inorganic contaminants, rust or scale from ferrous
metals, copper, and aluminum alloy. A solution called pickle
liquor, which contains strong acids is used to remove the surface
impurities. It is commonly used to descale or clean steel in various
steelmaking processes.
Process
Many hot working processes and other processes that occur at high
temperatures leave a discoloring oxide layer or scale on the
surface. In order to remove the scale the work piece is dipped into
a vat of pickle liquor.
The primary acid used is hydrochloric acid, although sulfuric acid
was previously more common. Hydrochloric acid is more
expensive than sulfuric acid, but it pickles much faster while
minimizing base metal loss. The speed is a requirement for
integration in automatic steel mills that run production at high
speed; speeds as high as 800 ft/min (-243 meters/min) have been
reported.
Carbon steels, with an alloy content less than or equal to 6%, are
often pickled in hydrochloric or sulfuric acid. Steels with alloy
content greater than 6% must be pickled in two steps and other
acids are used, such as phosphoric, nitric and hydrofluoric acid.
Rust- and acid-resistant chromium-nickel steels are pickled in a
bath of hydrochloric and nitric acid. Most copper alloys are pickled
in dilute sulfuric acid, but brass is pickled in concentrated sulfuric
and nitric acid mixed with sodium chloride and soot.
14. In jewelry making, pickling is used to remove the oxidation layer
from copper surfaces, which occurs after heating. A diluted
sulfuric acid pickling bath is used. Sheet steel that undergoes acid
picking will oxidize (rust) when exposed to atmospheric conditions
of moderately high humidity. For this reason, a thin film of oil or
similar waterproof coating is applied to create a barrier to moisture
in the air. This oil film must later be removed for much fabrication,
Plating or painting processes.
Steel pickling is part of the finishing process in the production of
certain steel products in which oxide and scale are removed from
the surface of strip steel, steel wire, and some other forms of steel,
by dissolution in acid. A solution of either hydrogen chloride (Hcl)
or sulfuric acid is generally used to treat carbon steel products,
while a combination of hydrofluoric and nitric acids is often used
for stainless steel. Steel pickling and the associated process of acid
regeneration result in the emission of hazardous air pollutants
(HAPs).
Pickling Process.
ROLLING MILL DEPARTMENT
15. In metalworking, rolling is a metal forming process in which metal
stock is passed through a pair of rolls. Rolling is classified
according to the temperature of the metal rolled. If the temperature
of the metal is above its recrystallization temperature, then the
process is termed as hot rolling. If the temperature of the metal is
below its recrystallization temperature, the process is termed as
cold rolling. In terms of usage, hot rolling processes more tonnage
than any other manufacturing process and cold rolling processes
the most tonnage out of all cold working processes.
There are many types of rolling processes, including fiat rolling,
foil rolling, ring rolling, roll bending, roll forming, profile rolling,
and controlled rolling.
Hot rolling is a metalworking process that occurs above the
recrystallization temperature of the material. After the grains
deform during processing, they recrystallize, which maintains an
equiaxertrnicrostnictiire and prevents the metal from wo.
Hardening. The starting material is usually large pieces of metal,
like semi-finished casting products, such as slabs, blooms, and
billets. If these products came from a continuous casting operation
the products are usually fed directly into the rolling mills at the
proper temperature. In smaller operations the material starts at
room temperature and must be heated. This is done in a gas- or oil-
fired soaking pit for larger work pieces and for smaller work pieces
induction heating is used. As the material is worked the
temperature must be monitored to make sure it remains above the
recrystallization temperature. To maintain a safety factor a
finishing temperature is defined above the recrystallization
temperature; this is usually 50 to 100 °C (122 to 212 °F) above the
recrystallization temperature. If the temperature does drop below
this temperature the material must be re-heated before more hot
rolling.
16. Hot rolled metals generally have little directionality in their
mechanical properties and deformation induced residual stresses.
However, in certain instances non-metallic inclusions will impart
some directionality and work pieces less than 20 mm (0.79 in)
thick often have some directional properties. Also, non-uniformed
cooling will induce a lot of residual stresses, which usually occurs
in shapes that have a non-uniform cross-section, such as I-beams
and H-beams. While the finished product is of good quality, the
surface is covered in mill scale, which is an oxide that forms at
high-temperatures. It is usually removed via pickling or the smooth
clean surface process, which reveals a smooth surface.
Dimensional tolerances are usually 2 to 5% of the overall
dimension.
Hot rolling is used mainly to produce sheet metal or simple cross
sections, such as rail tracks.
Material Specification:-
Pickled HR coil/ annealed CR Coil of various Grades
Dimensional Specification:-
Min. Max.
Width 700MM 1700MM
Material I/P Thickness 1.8MM (HR) 7.0MM
Wt. of coil 3.0MT 30MT
CR Thickness 0.11MM 6.95MM
Line Specification:-
Maximum Speed 1200MPM
Tension 16 T max.
17. ECL DEPEARTMENT
Electrochemical Cleaning (ECL). Is a very effective process using
the same physic. Equipment and chemicals we use in our
proprietary "spot" electro polishing technique. Discovered when a
customer had a product residue issue that looked like classic
"rouge" yet when industry accepted de-rouging chemical
applications were tried they proved completely ineffective. In an
experiment we used the spot electro polish procedure whereby
electrolyte was applied to the stained surface and the DC current
was activated and the "hand tool" was applied to and moved over
the surface the stain was removed immediately. Because of this
discovery we were able to completely clean 5, 10,15K GALLON
& larger vessels in hours instead of days.
Once discovered this method has found several v, cost effective
applications where ECC can be used in place A more expensive
and less effective chemical or manual processes while delivering a
micro surface improvement to the area being cleaned where
optional processes at best do nothing to improve and at worst can
etch the micro surface.
Application
De-rouging: ECC has been found to be very effective for
removing rouge for both electro polished and non-electro polish.
Surfaces. An added benefit observed on items de-rouged using
ECC is the rouge is very slow to return. Though conventional de-
rouging and passivation methods would yield a clean product
contact surface the rouge would begin to reform in a matter of
hours. Equipment de-rouged using ECC has shown the rouge
resisted returning for months and in some cases years.
18. Grey Residue: On equipment with a sanded or mechanically
polished stainless steel surface only it is common to find a grey
residue present when the surface is wiped with an alcohol soaked
cloth. In many instances the entire surface of a vessel, as an
example, will be hand wiped for hours using "clean wipes" until all
of the grey residue has appear. To have been removed. The vessel
may then be passivated or cleaned in place and allowed to dry only
to have the grey residue return at visibly the same concentration as
observed before the cleaning operation.
It is believed this grey residue is made up of stainless stool powder
created by the sanding process and electro statically adhered to the
mechanically polish. Surface (PIC). No amount of wiping or
chemical cleaning has proven to completely remove this residue.
Understandably Quality Control personnel find this condition
unacceptable concerned if the grey residue can be wiped off, it
stands to reason it can come loose during product processing and
become an undesirable additive.
ECC can completely remove this grey residue in one application
by electrolytic action as metal is removed ion by ion with the very
outermost surface and any residue being removed. In dozens of
applications this condition has successfully been treated in one
application eliminating grey residue from the equation.
Weld Scale and Discoloration: Prior to successful use as a de-
rouging of surface contaminant removal process, ECC was
developed specifically for removing weld discoloration directly on
a weld of in the heat affected zone. Adjacent to the weld. The
process utilizes a mild acid electrolyte solution and DC current that
when applied to a weld or heat affected zone (H.) very rapidly
removes discoloration. On large construction projects utilizing
austenitic, super- autarkic or nickel alloys, weld discoloration has
19. historically been removed by mechanical polishing, blasting or a
harsh chemical application, all of which alter the appearing when
compared to untreated surround', surfaces. The proce. Has also
been shown to improve corrosion resistance in the. Areas
comparable to that of the surrounding base metal.
ANNEALING DEPARTMENT
Annealing, in metallurgy and materials science, is a heat treatment
wherein a material is altered, causing changes in its properties such
as strength and hardness. It is a process that produces conditions by
heating to above the recrystallization temperature, maintaining a
suitable temperature, and then cooling. Annealing is used to induce
ductility, soften material, relieve internal stresses, refine the
structure by making it homogeneous, and improve cold wowing
properties.
In the cases of copper, steel, silver, and brass, this process is
performed by substantially heating the material (generally until
glowing) for a while and allowing it to cool. Unlike ferrous metals
—which must be cooled slowly to anneal—copper, silver and brass
can be cooled slowly in air or quickly by quenching in water. In
this fashion the metal is softened and prepared for further wo. Such
as shaping, stamping, or forming.
Thermodynamics
Annealing occurs by the diffusion of atoms within a solid material,
so that the material progresses towards its equilibrium state. Heat
is needed to increase the rate of diffusion by providing the energy
needed to break bonds. The movement of atoms has the effect of
redistributing and destroying the dislocations in metals and (to a
20. lesser extent) in ceramics. This alteration in dislocations allows
metals to deform more easily, so increases their ductility.
The amount of process-initiating Gibbs free energy in a deformed
metal is also reduced by the annealing process. In practice and
industry, this reduction of Gibbs free energy is tenned "stress
relief". •
The relief of internal stresses is a thermodynamically spontaneous
process; however, at room temperatures, it is a very slow process.
The high temperatures at which the annealing process occurs serve
to accelerate this process.
The reaction facilitating the return of the cold-worked metal to its
stress-free state has many reaction pathways, mostly involving the
elimination of lattice vacancy gradients within the body of the
metal. The creation of lattice vacancies is governed by the
Arrhenius equation, and the migration/diffusion of lattice
vacancies are governed by Fick's laws of diffusion. Mechanical
properties, such as hardness and ductility, change as dislocations
are eliminated and the metal's crystal lattice is altered. On heating
at specific temperature and cooling it is possible to bring the atom
at the right lattice site and new grain growth can improve the
mechanical properties.
Stages
There are three stages in the annealing process, with the first being
the recovery phase, which results in softening of the metal through
removal of crystal defects (the primary type of which is the linear
defect called a dislocation) and the internal stresses which they
cause. Recovery phase covers all annealing phenomena that occur
before the appearance of new strain-free grains. The second phase
is recrystallization, where new strain-free grains nucleate and grow
to replace those deformed by internal stresses. If annealing is
allowed to continue once recrystallization has been completed,
grain growth will occur, in which the microstructure starts to
21. coarsen and may cause the metal to have less than satisfactory
mechanical properties.
Controlled atmospheres
The high temperature of annealing may result in oxidation of the
metal's surface, resulting in scale. If scale is to be avoided,
annealing is carried out in a special atmosphere, such as with
endothermic gas (a mixture of carbon monoxide, hydrogen gas,
and nitrogen gas).
The magnetic properties of mu-metal (Espey cores) are introduced
by annealing the alloy in a hydrogen atmosphere.
Setup and equipment
Typically, large ovens are used for the annealing process. The
inside of the oven is large enough to place the wo.piece in a
position to receive maximum exposure to the circulating heated air.
For high volume process annealing, gas fired conveyor furnaces
are often used. For large workpieces or high quantity parts Car-
bottom furnaces will be used in order to move the parts in and out
with ease. Once theannealing process has been successfully
completed, the workpieces are sometimes left in the oven in order
for the parts to have a controlled cooling process. While some
workpieces are left in the oven to cool in a controlled fashion,
other materials and alloys are removed from the oven. After being
removed from the oven, the workpieces are often quickly cooled
off in a process known as quench hardening. Some typical methods
of quench hardening materials involve the use of media such as air,
water, oil, or salt.
Diffusion annealing of semiconductors In the semiconductor
industry, silicon wafers are annealed, so that dopant atoms, usually
boron, phosphorus or arsenic, can diffuse into substitutional
positions in the crystal lattice, resulting in drastic changes in the
electrical properties of the semi conducting material.
Normalization
22. Normalization is an annealing process in which a metal is cooled
in air after heating in order to relieve stress.
It can also be referred to as: Heating a ferrous alloy to a suitable
temperature above the transformation temperature range and
cooling in air to a temperature substantially below the
transformation range. This process is typically confined to
hardenable steel. It is used to refine grains which have been
defamed through cold work, and can improve ductility and
toughness of the steel. It involves heating the steel to just above its
upper critical point. It is soaked for a short period then allowed to
cool in air. Small grains are formed which give a much harder and
tougher metal with normal tensile strength and not the maximum
ductility achieved by annealing. It eliminates columnar grains and
dendritic segregation that sometimes occurs during casting.
Nornializing improves machinability of a component and provides
dimensional stability if subjected to further heat treatment
processes. Process annealing Process annealing, also called
"intermediate annealing", "subcritical annealing", or "in-process
annealing", is ahttreatment cycle that restores some of the ductility
to a WO. Piece allowing it be worked further without breaking.
Ductility is important in shaping and creating a more refined piece
of WO. Through processes such as rolling, drawing, forging,
spinning, extruding and heading. The piece is heated to a
temperature typically below the austenizing temperature, a. held
there long enough to relieve stresses in the metal. The piece is
finally cooled slowly to room temperature. It is then ready again
for additional cold working. This can also be used to ensure there
is reduced risk of distortion of the work piece during machining,
welding, or further heat treatment cycles.
23. SKIN PASS MILL
After annealing, coils may require a final rolling called a temper
pass, skin pass or planish pass. This involves a controlled light
reduction to establish the final thickness, impart the desired surface
finish, flatten the strip to improve shape and create the required
hardness or temper of the material.
24. COLD ROLL SLITTING / CUT TO LENGTH
Some customers require a steel to be of a particular thickness other
than the general increment sizes rolled in the hot mill or thinner
than the minimum thickness rolled in the mills. These steels are
processed in the cold roll reduction mill. These mills are capable of
rolling steel to the precise thickness that the customer orders and
are a major part of the steel strip production process. The reduction
mill in the plant I worked had four rolls in the mill that were
stacked upon each other. This arrangement is known as a two high
mill. There are two working rolls between which the strip is passed
and two large back-up rolls, one on top of the working rolls and
one on the bottom. The back-up rolls apply the tremendous
25. pressures required to cold roll (reduce) the strip between the
working rolls. The working rolls are usually about two to three feet
in diameter while the back-up rolls are about seven to eight feet in
diameter. The rolls are made of high alloy steel so they can
withstand the tremendous pressure they are under while rolling
without deforming.
Because of this the rolls are ground in a large lathe using a very
large grinding wheel on a movable carriage. Depending on the
surface finish required of the strip the working rolls will either
have a highly polished (mirror like) finish or a dull finish on them.
All working rolls are ground on the lathe in the mill to a highly
polished surface periodically. The rolls that have a dull finish on
them are shot blasted after grinding to produce the desired surface.
After grinding to a polished surface the rolls that need a dull finish
are placed on a large carriage which has a set of rubber rolls on it.
The carriage then travels on a small rail track into a large enclosure
and the door is closed down. On top of this enclosure is a large
hopper filled with fine steel balls called shot. This shot is very
small in diameter (about half the size of a BB or smaller) and is
very hard. It is fed down a chute and using either compressed air or
a impeller type system it is accelerated to high speed (in excess of
a hundred miles per hour) and blasted against the surface of the
roll. The rubber rolls on the carriage rotate causing the steel roll to
rotate so all its surface is exposed to the shot blast. The shot comes
in a variety of sizes and hardness grades and different types are
used depending on the type of surface finish required on the rolls.
After a predetermined cycle time the roll is removed from the
Wheelabrator, as it is called and is ready to be used in the mill.
26. A saddle type conveyor runs along the side of the reduction mill.
Steel coils are place on this conveyor by overhead cranes using the
same .C. hook as at the entry and exit ends of the pickle lines. This
saddle conveyor moves the coils along to the reduction mill where
they are lowered onto a frame at the entry side of the mill. A
transfer saddle operated by the mill operator moves out to the
frame and picks up the coil and moves it back into the feed
mandrel on the entry side. The operator cuts the strap, freeing up
the loose end of the coil. He opens a space between the work rolls
and feeds the end of the exit side. On the exit side is another
expandable mandrel the same as the catcher mandrels of the hot
mills and pickle line. The entry operator feed the strip until the exit
operator can catch the end in the open segment of his mandrel,
expanding it and trapping the end of the strip. The entry operator
then closes the gap in the working rolls down on the strip. Pressure
(thousands of tons) is applied by the back-up rolls by means of
hydraulically operated screws, to the wowing rolls and the
reduction rolling process begins. If the thickness of the steel needs
to be greatly reduced, the strip will be passed back and forth
between the rolls a number of times with the rolls adjusted for each
pass. Due to the great amount of pressure exerted in the reduction
process the steel strip becomes very hot. In order to prevent the
steel from becoming hot and sticking to the work rolls, the rolls are
flooded with a coolant consisting of 95% water and the other 5%
water soluble oil. The end of the strip that is in the exit mandrel is
not released in the multiple pass process nor is it completely
unwound from the entry mandrel. In the final pass through the
reduction mill, the portion that was not reduced from the entry end
is trimmed off in a set shears just before they enter the work rolls
to the exit side. A transfer saddle on the exit side then moves the
coil back onto the conveyor that runs beside the mill.
27. QUALITY SYSYTEM
Quality control is a process by which entities review the quality of
all factors involved in production. This approach places an
emphasis on three aspects
1. Elements such as controls, job management, defined and well
managed processes, performance and integrity criteria, and
identification of records
2. Competence, such as knowledge, skills, experience, a.
Qualifications
3. Soft elements, such as personnel integrity, confidence
organizational
The quality of the outputs frisk if any of these three aspects is
deficient in any way.
Quality control emphasizes testing of products to uncover defects,
and reporting to management who make the decision to allow or
deny the release, whereas quality assurance attempts to improve
and stabilize production, and associated processes, to avoid, or at
least minimize, issues that led to the defects in the first pun For
contract work, particularly work awarded by government agencies,
quality control issues are among the top reasons for not renewing a
contract.
"Total quality control", also called total quality management, is an
approach that extends beyond ordinary statistical quality control
techniques and quality improvement methods. It implies a
complete overview and re-evaluation of the specification of a
product, rather than just considering a more limited set of
changeable features within an existing product. If the original
specification does not reflect the correct quality requirements,
28. quality cannot be inspected or manufactured into the product. For
instance, the design of a pressure vessel should include not only
the material and dimensions, but also operating, environmental,
safety, reliability and maintainability requirements, and
documentation of findings about these requirements.
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