This document is a report on a case study of profiles of electrical steel conducted by two students, G Pranay Raj and K Gautham Reddy, at Rourkela Steel Plant in June-July 2013. It provides an overview of the processes involved in manufacturing electrical steel, including the hot strip mill, silicon steel mill, bust line, annealing and pickling line, cold reversing mill, and slitter line. The report includes graphs of profiles measured from 20 coils of steel and an analysis of observations made during the study. The aim was to understand how the steel's profile affects quality and suggest ways to prevent issues like buckling and scratches during processing.

1. 1
A REPORT ON
CASE STUDY OF PROFILES OF ELECTRICAL STEEL
BY
G PRANAY RAJ (2011B4A4630H)
K GAUTHAM REDDY (2011A8PS364G)
AT
ROURKELA STEEL PLANT
A Practice School-I Station Of
BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE, PILANI
(JUNE-JULY, 2013)

2. 2
A REPORT ON
CASE STUDY OF PROFILES OF ELECTICAL STEEL
BY
G PRANAY RAJ 2011B4A4630H
MSc. Math + B.E.MECH
K GAUTHAM REDDY 2011A8PS364G
B.E. ELECTRONICS & INSTR
Prepared in partial fulfillment of the
Practice School-I Course No
BITS C221/BITS C231/BITS C241/BITS GC221/BITS
GC231
AT
ROURKELA STEEL PLANT
A Practice School-I Station of
BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE,
PILANI
(JUNE-JULY, 2013)

3. 3
BIRLA INSTITUTE OF TECHNOLOGY AND SCIENCE
PILANI(RAJASTHAN)
Practice School Division
Station: ROURKELA STEEL PLANT Centre: ROURKELA
Duration:From 12th
June 2013 to: 7th
July 2013
Date of Submission: 8th
July 2013
Title of the Project:Case study of profiles of electrical steel
ID No. Name(s) of student(s) Discipline
2011B4A4630H G PRANAY RAJ MSc MATH + B.E. MECH
2011A8PS364G K GAUTHAMREDDY B.E. ELECTRONICS & INSTR.
Name(s) of expert Designation
Mr. Muthuswamy DGM, R&C LAB
Mr. CHANDANSAMAL Sr. Manager, Metallography department, R&C
LAB
Name of the PS Faculty: Mr. TUFAN CHANDRA BEHRA & Mrs. MONALISA MISHRA
Key Words: PROFILE, CRNO STEEL, BUCKLING, OVERCURING
Project Area: SILICONSTEEL(ELECTRICAL STEEL)

4. 4
Abstract:
Quality is a major concern for a very big industry like the Rourkela steel plant.
Since RSP is the only steel plant that produces silicon steel in the whole
country it needs to haveproper quality assurancestandards, so as to satisfy
the costumers and also diminish their losses. Oneof the major factors that
contribute to the silicon steel’s quality is its profile (it’s a systematic study of
the variation of the coils thickness along its width). Our projectincludes the
study of profiles of 20 coils, and observethe changes its undergoing through
the silicon steel mill and relating it to the final productand its quality to
understand its importance, and also understand the amounts of steel which is
wasted in the process and suggestmeasures to be taken to prevent events like
buckling, scratches, overcuring, black surfaceand coil breakages over the
surfaceof silicon steel.
Pranay Raj
Gautham Reddy
Signature(s) of Student(s) Signature of PS Faculty
Date 7-07-2013 Date

5. 5
ACKNOWLEDGEMENT
We thank Mr. Tufan Chandra Behera and Mrs. Monalisa Mishra for
guiding us through this practice school. They have been really helpful
in making the stay in Rourkela memorable and our experiences rich.
We are also thankful to Mr. Muthuswamy (DGM, R&C lab) and Mr.
Chandan Samal for spending their valuable time and giving us this
great opportunity to work under their guidance. We would also like
to thank Mr. Saroj Das and Mr. K.K.Biswal for guiding us throughout
the project and the opportunity to learn about the silicon steel mill
and its functioning, and we are also thankful for their patience and
their interest in letting us know things. Finally, we thank the PS
division for giving us this wonderful opportunity of working in
Rourkela Steel Plant.

6. 6
INDEX
ABOUT ROURKELA STEEL PLANT ………………………………………………………………… 7
1) INTRODUCTION ……………………………………………………………………………………… 8
1.1) DESCRIPTION OF PROCESS AT HOT STRIP MILL …………………………………. 8
1.2) DATA FROM HOT STRIP MILL …………………………………………………………….. 10
1.3) Material flow chart that takes place at hot strip mill…………………… 11
2) BRIEF DESCRIPTIONOF PROCESS THATTAKES PLACE
AT SILICONSTEEL MILL……………………………………………………………………. 12
2.1.1) BUST LINE………………………………………………………………………………. 12
2.1.2) ANNEALING AND PICKLING LINE…………………………………………….. 12
2.1.3) COLD REVERSING MILL………………………………………………………….. 13
2.1.3.1) HEATGENERATIONINTHECOLD ROLLING PROCESS………. 14
2.1.3.2) DYNAMICHEATEXCHANGEINTHE MOVING
STRIP AND ROTATING ROLL……………………………………………. 15
2.1.3.3) HeatBalance…………………………………………………………………. 16
2.1.4) TA OR DECARB LINE…………………………………………………………….. 17
2.1.5) SLITTER LINE……………………………………………………………………….. 17
2.2) PROCESS FLOW CHARTTHAT TAKES PLACE AT SILICONSTEEL MILL. 18
3) PROFILE………………………………………………………………………………………….. 19
4) OBSERVATIONS MADEIN THEBUST Line………………………………………. 20
5) OBSERVATION MADEINTHESLITTERLINE………………………………………. 23
6) GRAPHS OF PROFILES OF COILS……………………………………………………….. 25
7) OBSERVATION AND ANALYSIS………………………………………………….......... 31
8) CONCLUSION......................................................................................... 34

7. 7
ABOUT ROURKELA STEEL PLANT
SAIL-RourkelaSteel Plant (RSP), located in Rourkela, Odisha the first
integrated steel plant in the public sector in India, was setup with German
collaboration with an installed capacity of 1 million tonnes in 60s.
Subsequently, its capacity was enhanced to 2 million tonnes. The RSP has
various firsts to its credit. It is the firstplant in Asia to adopt the energy-
efficient LD process of steel making and the firstintegrated steel plant of SAIL
which adopted the costeffective and quality centred continuous casting route
to process 100% of steel produced. The plant has also, for the firsttime in
India, had adopted external desulphurisation of hot metal by calcium carbide
injection process. RSP is one of the unique steel units under the SAIL umbrella
with a wide variety of special purposesteels.
The Republic of Germany provided technical knowhow for the construction of
the steel plant. German metallurgical firms Mannesmann, Krupp,
Demag, Siemens and Voestalpine providemachinery and consultancy to the
plant among others. Rourkela Steel Plant was the firststeel plant in Asia to
utilize the LD (Linz-Donawitz) processof steel-making. Rourkela Steel Plant also
has an associated Fertilizer Plant that produces nitrogenous fertilizers using
ammonia feedstock (fromits coke oven plant).
RSP presently has the capacity to produce2 million tonnes of hot metal, 1.9
million tonnes of crude steel and 1.67 million tonnes of saleable steel. Itis
SAIL’s only plantthat produces silicon steels for the power sector, high quality
pipes for the oil & gas sector and tin plates for the packaging industry. Its wide
and sophisticated productrange includes various flat, tubular and coated
products.

8. 8
1) INTRODUCTION
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 aboveits 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 moretonnage than any
other manufacturing process, and cold rolling processes the mosttonnage out
of all cold working processes.
Rourkela Steel Plant, a unit of Steel Authority of IndiaLimited(SAIL) took the
lead & achieved the distinction of being the firstin the country to start
commercial production of CRNO. Equipped with the state of the art
technology, SiliconSteel Mill with installed capacity to produce73,500 tpa of
CRNO was set up with technical collaboration of M/s A.K.STEELS (Formerly
ARMCO), USA, a pioneer in the field of electrical steel. Silicon Steel Mill is ISO –
9001 & ISO –14001 Unit. The CRNO stream has been awarded ISO - 9001, the
InternationalQuality AssuranceSystem, certified by M/s RWTUV, Germany in
September 1996. And ISO –14001EnvironmentalManagementSystem,
certified by M/s BIS, India in October 2000.
Meeting international standards with respect to magnetic properties,
insulation coating properties, insulation resistivity, dimensionaltolerance &
lamination factor is the credo at Silicon Steel Mill. Various facilities havebeen
added with a view to keep pace with the latest technology. The notable
features are external desulphurisation of hot metal, high purity steel making,
vacuumdegassing, continuous casting, and highly accurate hot rolling mill &
Cold Rolling Mill complex incorporating the mostadvanced technology for
manufacturing CRNO steel strips. The unit has a modern Magnetic Testing
Laboratory, which is one of its kinds in the country.
For the production of CRNO steel, slabs produced in SMS is firstly processed in
hot strip mill to produceHR coils of desired thickness and width which are the
sent to silicon steel mill for further processing.

9. 9
1 .1) Brief descriptionof process that takes place at hot stripmill:
1) Walking BeamFurnaces:
• Each Furnacehas 6 zones
• Slabs are put on charging side roller table with the help of depiler crane
• slab is extracted fromfurnaceby extractor and is placed on the
dischargeroller table and sent to Ro/Vo
2) Primary Descaler:
• To remove the scale formed on the surfaceof slabs during its heating
inside furnaces
• Water jet at high pressureof 145-160 Bar is applied on top and bottom
surfaceof slabs.
3) Roughing Stand:
• R0/V0: Heated slabs reduced to desired thickness and sent to R1. Slabs
after rolling at R0/V0 are called Intermediate Transfer Bars
• ROUGHING STAND-I (R1) :Bars fromRo given 3 to 5 passes and reduced
to desired thickness
• ROUGHING STAND-II (R2):Thethickness of thebar fromR1 reduced
further
4) Coil Box:
• The Intermediate Transfer Bar is coiled and subsequently uncoiled to
feed tail end of transfer bar into the Finishing Mills.
5) Finishing Mill:
• Reduction is given to the bar in each of the 6 stands.
• The strip temperature is controlled on Run Out Table (ROT) having 4
cooling banks
6) Coilers:

10. 10
• The strip gets coiled in one of the two hydraulic down coilers
• The hot coils are circumferentially strapped on the body by Automatic
Strapping Machine and marked for identification.
• Necessary samples arecut fromthe coils for its testing.
• Coils are then transferred to coil yard and are allowed to cool before
they are sent for further processing in different units of RSP
7) Dividing Line:
• Hot Rolled Coils meant for converting into HR plates are uncoiled in
Uncoiler and levelled in Leveler-I
• Sheared at Dividing Shear to the required lengths
• Then plates are levelled once again in Leveler-II and piled in Pilers
1.2) Data from hot stripmill:
Coiling temperature: 660-770C
Rolling temperature: 1040-1050C
Finishing temperature: 860-880 C

11. 11
1.3) Material flow chart that takes place at hot stripmill:

12. 12
2) BRIEF DESCRIPTION OF PROCESS THATTAKES PLACE AT SILICON STEEL
MILL:
Cold Rolled Non-oriented (CRNO) steel produced here is the energy efficient
steel, is an essential raw material recognized the world over for manufacturing
electrical equipment like generators, motors, relays, smalltransformers etc.
Used primarily in special rotating and static electrical equipment, the CRNO
steel is characterized by low watt loss (coreloss) and high permeability
Silicon steel mill receives inputs fromhot strip mill as HR coils with initial width
of 1055mmand initial thickness between 2.2 to 2.5mm.
2.1.1) BUSTLINE:
Firstly it is processed in the BUST line (build up and side trim line) where side
trimming of the coil takes place wherethe width of the coil is reduced from
1055 mmto 1025/975/925mm.
Line Features:
1. Coil Wt. 15 Mt (max)
2. Coil I.D. 510 & 710 mm, Width: 600 To 1150 mm
3. Electronic Weigh Bridge
4. Line speed 15 to 125 mpm.
5. Jog speed 15 mpm
6. Line tension 1.75 Kg / mm2
2.1.2) ANNEALING AND PICKLING LINE:
This line is used for pickling of HR coils after BUST line.
Line Features:
1. Hydrochloric acid pickling (HCL) 5 tanks for pickling.
2. Acid conc. 8 To 12 %. Salt conc. 12 % max.

13. 13
3. Acid bath temp. 70 +/- 3oC
4. Annealing of M-36 / M-27 & higher grades.
5. Gas fired & electric heating zones 3 each.
6. Annealing temp. 950 +/- 10oC
7. Anti-rustoil coating after pickling.
8. Taylor - Winfield shifting head seamwelding m/c
9. Line speed 10-35 mpm (Entry-90 /Process 60 /Exit 90 mpm )
10. Tension - Entry - 0.35 to 1.05 Kg/mm2
Furnace- 0.35 to 1.05 Kg/mm2
Pickling - 1.05 Kg/mm2
Exit - 2.5 Kg/ mm 2
11. Pickling Tanks - 5 (L - 25. 7 m, W - 2.13 m, Depth - 1.207 m)
Capacity - 36,000 Lts each (1 to 3) 4A – 16800, 4B-19600 lts.
12. Cascaderinse unit 3 compartments.
2.1.3) COLD REVERSING MILL:
Cold rolling occurs with the metal below its recrystallization temperature
(usually at room temperature), which increases the strength via strain
hardening up to 20%. Italso improves the surfacefinish and holds tighter
tolerances. Commonly cold-rolled products include sheets, strips, bars, and
rods; these products areusually smaller than the same products thatare hot
rolled. Because of the smaller sizeof the work pieces and their greater
strength, as compared to hot rolled stock, four-high or cluster mills are used.
Cold rolling cannot reduce the thickness of a work piece as much as hot rolling
in a single pass.
After annealing and pickling the coil goes to cold reversing mill where the
thickness of the coil is reduced from2.2 to 2.5 mm to 0.5 mm in 5 to 6 passes

14. 14
by applying pressure. Herein each pass the thickness is reduced not morethan
33%.
2.1.3.1) HEATGENERATION IN THECOLD ROLLING PROCESS
The Area of Contact (roll and Strip) between the hard work roll surfaceand the
softer steel strip surfaceis wherefriction is created, deformation occurs and
heat is generated. The “Area of contact” is defined by the strip width in the
transverseplaneand the circumferential “Arc of Contact” (AoC) between the
roll and strip.
The area of contact varies with the changing AoC and the strip width thus a
small reduction gives a shortarc of contact and combined with a narrow strip
with gives a smaller area of contact and vice versa.
The heat generated at the frictional interface (Area of Contact) and through
the energy used in deformation is transferred into both the strip and the roll in
the roll bite. In this mill as pressureis applied, heat is generated so hot water is
used as a coolant.
(i) 4 Hi Mill Roll Stack (iii) Area of Contact

15. 15
2.1.3.2) DYNAMIC HEATEXCHANGEIN THE MOVING STRIP AND ROTATING
ROLL
In the rolling process wherethe area mass ratio is higher becausethe gauge is
“thin” a large proportion of the “strip heat” is lost to air with further losses to
such things as coolant wash-over, however, heatabsorbed by the rotating roll
is subjectto a more complex thermal mechanism.
Heat will continuously migrate to cooler zones in and out of the roll body due
to the localized elevated temperature in the area of contact (bite) and localized
“chill zones” created in the impingement areas of coolant sprays on the
surface.
This localized heat input / output process results in a non-uniformdistribution
of heat, circumferentially around the roll and transversely across theroll body.
Additionally the roll is subjected to Thermal and Mechanical Fatigue during
rolling:
i) Thermal fatigue as the roll cycles through the elevated temperatures in the
roll bite and the lower temperature zones cooled under the coolant spray
footprints.
ii) Mechanical Fatigue by mechanical compression (flattening) and physical
distortion (deflection) caused by the rolling forceand the necessary torque
applied by the motor.
High reduction schedules combined with the requirement to producea
widening rangeof material cross-sectionsand a more varied rangeof softer
and harder materials, results in increasingly greater challenges in the control of
roll temperature and the effective transfer / extraction of heat.

16. 16
Given the more diverserange of thermal conditions it is important to install
efficient and robustrollcooling systems that can establish both heat balance
and controllable thermal conditions around the work roll as well as across its
width by controlled selective cooling and efficient heat transfer.
2.1.3.3) Heat Balance:
To establish heat balance it is imperative that heat transferred into the roll is
transferred out, however as the heat input and output is not distributed
uniformly the fundamental requirement to achieve effective heat extraction is
to ensure
i)The roll surfacetemperaturerange around the circumference is minimized
which reduces thermal fatigue and roll surfacedegradation as well as lowering
the potential for surfacedefects, impaired lubricant performanceand roll
wear.
ii)The transversetemperaturedistribution is controlled to assurestrip flatness
is not affected by excessivethermal crowning or excessive localized expansion
across the rolling width and in particular at the edges (edge waves).
The average roll temperature is difficult to establish during the rolling process
but the difference in the temperature at the exit of the roll bite will represent
the highestvalue in the range and the temperature after the final cooling zone,

17. 17
in the area ahead of the entry bite should representthe lowestin the range
around the circumference: it is necessary to apply coolant and configuresprays
such that the difference in those two values is minimized.
Itis also imperative to establish the same “temperature profile” on both top
and bottom rolls as a pair to avoid differential thermal crowns and transverse
profiles
2.1.4) TA OR DECARB LINE:
Then it goes to TA or decarb line wherecarbon content is reduced firstly and
then coating takes place which can either be organic, inorganic or semi
organic.
2.1.5) SLITTER LINE:
Then it finally goes into the slitter line wherethe final inspection of the coil
takes place for any defects like buckling, coil breakage, over curing, black
surface, scratch etc. and side trimming is done as per the requirement of the
customer.
Then it is packed and finally dispatched to the customer.

18. 18
2.2) PROCESS FLOWCHARTTHAT TAKES PLACEAT SILICON STEEL MILL:

19. 19
3)Profile
Profile is made up of the measurements of crown and wedge. Crown is the
thickness in the center as compared to the averagethickness at the edges of
the work piece. Wedge is a measureof the thickness at one edge as opposed
to the other edge. Both may be expressed as absolutemeasurements or as
relative measurements. For instance, one could have 2 mil of crown (the
center of the work piece is 2 mil thicker than the edges), or one could have 2%
crown (the center of the work piece is 2% thicker than the edges). Itis typically
desirable to have somecrown in the work piece as this will causethe work
piece to tend to pull to the center of the mill, and thus will run with higher
stability.
We have examined a sampleof 20 coils of different grades like 60A,70B,53C
near the BUST line(build up and side trim line )and took the data of defects in
them such as buckling, coil breakage, scratch, black surfaceetc. in the slitter
line and observed which profile of the coil causes defects like buckling and
others.

20. 20
4) Observations made in the BUST line (profile measuredfromoperator side
to other side inmm at 5 points in mm at beginning, middle and endof
the coil):
Fromoperatorsidetootherside
SNO HSMNO SSMNO TAandDECARBno PROFILE
head1 mid1 centre mid2 head2
1 91790 70B-3425 TA-4160 2.41 2.41 2.41 2.43 2.42
2.4 2.41 2.41 2.41 2.39
2.39 2.41 2.41 2.42 2.41
2 91785 70B-3426 TA-4124 2.65 2.63 2.61 2.66 2.65
2.39 2.39 2.4 2.41 2.4
2.33 2.34 2.34 2.36 2.35
3 91791 70B-3427 TA-4148 2.58 2.59 2.59 2.59 2.57
2.36 2.37 2.37 2.38 2.38
2.45 2.46 2.45 2.46 2.45
4 91770 60A-4496 DE-4424 2.71 2.71 2.71 2.71 2.71
2.45 2.45 2.44 2.45 2.45
2.4 2.4 2.4 2.42 2.42
5 91772 60A-4497 TA-4140 2.32 2.32 2.32 2.32 2.32
2.32 2.33 2.31 2.32 2.32
2.4 2.42 2.42 2.41 2.41
6 92266 60A-4508 TA-4150 2.38 2.36 2.41 2.4 2.4
2.45 2.45 2.42 2.42 2.42
2.47 2.47 2.46 2.46 2.45
7 92267 60A-4509 TA-4151 2.34 2.33 2.33 2.34 2.33
2.33 2.32 2.32 2.31 2.3
2.41 2.39 2.39 2.38 2.38

21. 21
8 92289 70B-3434 DE-4324 2.53 2.53 2.51 2.52 2.5
2.6 2.56 2.54 2.56 2.54
2.52 2.53 2.51 2.52 2.53
9 92284 60A-4510 DE-4326 2.57 2.56 2.55 2.55 2.54
2.53 2.54 2.54 2.55 2.54
2.65 2.66 2.66 2.66 2.64
10 92269 60A-4511 TA-4161 2.55 2.52 2.52 2.53 2.51
2.54 2.53 2.52 2.52 2.51
2.65 2.64 2.63 2.6 2.61
11 93099 53A-4656 TA-4196 2.68 2.65 2.61 2.59 2.56
2.46 2.44 2.43 2.42 2.41
2.3 2.3 2.3 2.3 2.3
12 93133 60A-4544 DE-4348 2.39 2.42 2.42 2.45 2.46
2.26 2.28 2.29 2.29 2.29
2.53 2.55 2.57 2.57 2.56
13 93098 53A-4657 TA-4261 2.61 2.6 2.6 2.59 2.56
2.29 2.28 2.29 2.3 2.29
2.56 2.55 2.56 2.57 2.57
14 93142 60A-4545 TA-4175 2.42 2.42 2.44 2.43 2.41
2.22 2.23 2.24 2.24 2.23
2.53 2.52 2.5 2.52 2.49
15 93100 53A-4658 TA-4191 2.46 2.46 2.45 2.45 2.44
2.28 2.27 2.27 2.27 2.21
2.53 2.52 2.52 2.51 2.49
16 93097 53A-4659 2.57 2.55 2.57 2.58 2.58
2.29 2.29 2.29 2.29 2.28
2.35 2.34 2.34 2.33 2.31

22. 22
17 93103 60A-4546 DE-4366 2.66 2.67 2.66 2.64 2.59
2.32 2.32 2.33 2.33 2.32
2.35 2.35 2.35 2.36 2.37
18 93146 60A-4547 TA-4234 2.19 2.2 2.21 2.21 2.2
2.42 2.43 2.44 2.44 2.42
2.51 2.53 2.54 2.56 2.55
19 93141 60A-4548 2.28 2.3 2.3 2.3 2.3
2.45 2.44 2.43 2.43 2.43
2.46 2.48 2.48 2.48 2.48
20 93114 60A-4549 2.56 2.57 2.57 2.57 2.56
2.42 2.43 2.42 2.43 2.43
2.72 2.72 2.7 2.72 2.7

23. 23
5) Data collectedfromthe slitter line (defects likebuckling, coil breakage
etc.):
S NO TA and DECARBno parts prime(mt) seconds(mt) REASONS
1 TA-4160 1 5.6 COILBREAKAGE
2 4.9
2 TA-4124 1 5.6 NO DEFECTS
2 5.2
3 TA-4148 1 5.9 NO DEFECTS
2 5.4
4 DE-4424 1 5.6 NODEFECTS
2 5.2
5 TA-4140 1 5.6 NODEFECTS
2 4.8
6 TA-4150 1 5.7 NODEFECTS
2 5.2
7 TA-4151 1 5.6 NODEFECTS
2 4.7
8 DE-4324 1 4.1 BUCKLING
2 6.1 BLACK SURFACE
9 DE-4326 1 5.3 SCRATCH
2 4.3 BLACK SURFACE
3 1.8
10 TA-4161 1 2 BUCKLING
2 2.3 OVERCURING
3 5.3

24. 24
11 TA-4196 1 5.3 NODEFECTS
2 3
12 DE-4348 1 5.6
2 5.1 SCRATCH
13 TA-4261 1 4.5 BUCKLING
2 4
14 TA-4175 1 5.6 NODEFECTS
2 5
15 TA-4191 1 1.3 BUCKLING
2 5 OVERCURING
3 4.1
16 BUSTLINECOILNOTPROCESSEDYETPROCESSED
17 DE-4366 1 2.1 BUCKLING
2 COILBREAKAGE
18 TA-4234 1 1.3 BUCKLING
2 5
3 4.1
19 BUSTLINECOILNOTYETPROCESSED
20 BUSTLINECOILNOTYETPROCESSED

25. 25
6) GRAPHS OF THE PROFILES OF THE COILS WE EXAMINED (middle part):
X AXIS: 5 EQUIDISTANTPOINTS ALONG THEWIDTH OF THE COIL
Y AXIS: THICKNESS OF THE COIL AT THAT POINTS (in mm)
2.38
2.385
2.39
2.395
2.4
2.405
2.41
2.415
head1 mid1 centre mid2 head2
TA-4160
TA-4160
2.38
2.385
2.39
2.395
2.4
2.405
2.41
2.415
head1 mid1 centre mid2 head2
TA-4124
TA-4124

26. 26
2.35
2.355
2.36
2.365
2.37
2.375
2.38
2.385
head1 mid1 centre mid2 head2
TA-4148
TA-4148
2.434
2.436
2.438
2.44
2.442
2.444
2.446
2.448
2.45
2.452
head1 mid1 centre mid2 head2
DE-4424
DE-4424
2.3
2.305
2.31
2.315
2.32
2.325
2.33
2.335
head1 mid1 centre mid2 head2
TA-4140
TA-4140

27. 27
2.405
2.41
2.415
2.42
2.425
2.43
2.435
2.44
2.445
2.45
2.455
head1 mid1 centre mid2 head2
TA-4150
TA-4150
2.285
2.29
2.295
2.3
2.305
2.31
2.315
2.32
2.325
2.33
2.335
head1 mid1 centre mid2 head2
TA-4151
TA-4151
2.51
2.52
2.53
2.54
2.55
2.56
2.57
2.58
2.59
2.6
2.61
head1 mid1 centre mid2 head2
DE-4324
DE-4324

28. 28
2.52
2.525
2.53
2.535
2.54
2.545
2.55
2.555
head1 mid1 centre mid2 head2
DE-4326
DE-4326
2.495
2.5
2.505
2.51
2.515
2.52
2.525
2.53
2.535
2.54
2.545
head1 mid1 centre mid2 head2
TA-4161
TA-4161
2.38
2.39
2.4
2.41
2.42
2.43
2.44
2.45
2.46
2.47
head1 mid1 centre mid2 head2
TA4196
TA4196

29. 29
2.245
2.25
2.255
2.26
2.265
2.27
2.275
2.28
2.285
2.29
2.295
head1 mid1 centre mid2 head2
DE-4348
DE-4348
2.27
2.275
2.28
2.285
2.29
2.295
2.3
2.305
head1 mid1 centre mid2 head2
TA-4261
TA-4261
2.21
2.215
2.22
2.225
2.23
2.235
2.24
2.245
head1 mid1 centre mid2 head2
TA-4175
TA-4175

30. 30
2.16
2.18
2.2
2.22
2.24
2.26
2.28
2.3
head1 mid1 centre mid2 head2
TA-4191
TA-4191
2.314
2.316
2.318
2.32
2.322
2.324
2.326
2.328
2.33
2.332
head1 mid1 centre mid2 head2
DE-4366
DE-4366
2.41
2.415
2.42
2.425
2.43
2.435
2.44
2.445
head1 mid1 centre mid2 head2
TA-4234
TA-4234

31. 31
7) Observationandanalysis:
So in the abovetable part of the coils which have no defects came under
prime which means it has a good surfaceand the coil which has defects like
buckling, BS etc. and doesn’thave a good surfacefinish will come under
seconds(non-prime).
Non-prime(Second & Defective) steel products may be defined as:-
i) Products of non-standard dimensions: provided they do not show the
defects or the physio-chemicalfaults of downgraded products, and that they
are sold and delivered in different or heterogeneous formats with no
guarantee or indication of quality.
ii) Downgraded products
Downgraded products means iron and steel products having:
(a) Surfacedefects
Some of the surfacedefects are:
Waviness / Buckling
Lack of flatness consisting of undulation (including waves and buckles) in the
surfaceof a sheet or plate. Troughs and crests on rolled products which may
occur along with waviness of edges.
Cracks
Discontinuity, usually of the hairline type:
- Longitudinal - parallel to rolling direction,
- Transverse-perpendicularto rolling direction,
- With scale or Y-shaped (forked).
Scratches
Scratches (singleor multiple) of mechanical origin on the surfaces of products
that can be felt by hand/ nail.

32. 32
Straightness andprofile:
Defects whereby the section or its cross- section depart fromthe required
dimensions and straightness by morethan the tolerances specified in
international technical standards.
(b) Internal faults
Physio-chemicalfaults concern the analytical and structuralcomposition of the
steel and/or presenceof presence of radioactive elements in the steel.
These faults are internal defect and make the productunusablein the
corresponding commercialquality. In general, these defects- such as
inclusions, split ends, piping, off chemistry etc. Cannotbe seen with the naked
eye. These defects are detected by ultrasonic methods, by mechanical and/ or
chemical tests. Presenceof radioactive elements, if any, may be detected by
radiation meter.
As in the case of products with the surfacedefects, the importer must declare
products with physio- chemical faults and supply documental evidence.
Customs checks on these faults may be carried out with the assistanceof a
competent verification agency including accredited chemical laboratory.
(c) Characteristics not conforming tothe values specifiedinthe National /
International standards specificationwithregard to:
 chemical analysis i.e. off chemistry,
 mechanical properties i.e. off mechanical properties,
 Dimensional tolerances i.e. off size.
 Magnetic properties, stacking factor, insulation resistivity etc. in caseof
electrical steel grades.

33. 33
The latter relates to one or more of the following aspects: length, width,
thickness, flatness, straightness, section.
The deviation fromcomplete flatness is the direct result of the work piece
relaxation after hot or cold rolling, due to the internal stress pattern caused by
the non-uniformtransversalcompressiveaction of the rolls and the uneven
geometrical properties of the entry material.
So out of 17 coils weexamined who’s total weight turns out to be 172.2T,
36.7 T has defects which accounts for 21 %.
So it is observed that coils that has defects has showed either or both of the
below profile trend
i) Coils with the thickness between adjacentpoints is greater than or equal to
0.02mm.ex: TA-4348
ii) coils with profile increasing or equal fromhead1 to mid2 and then there is a
sudden decrease of thickness at head2(lastpartof the coil).ex:DE-4234
2.245
2.25
2.255
2.26
2.265
2.27
2.275
2.28
2.285
2.29
2.295
head1 mid1 centre mid2 head2
DE-4348
DE-4348

34. 34
So in order to avoid defects it is recommended to take measures to avoid the
above two kinds of profiles in HR coils
8) CONCLUSION:
• Proper rolls are to be selectedinthe rolling mill.
So as to reduce the expansion of the rolls and to avoid any kind of
changes in the diameter which in turn affects the profile of the coils
• Proper surface finishand temperaturesare tobe maintained.
Maintenance of temperature with efficient cooling systems prevents
uneven expansion of the rolls.
• Proper lubricationand coolants are to be used.
Lubrication avoids unnecessary bonding between the surfaceof the rolls
and the coils and prevents and diminishes frictional impact. Making the
coil-making process under control. And coolants maintain the proper
temperature and help the rolls and coils avoid any kind of fatigues.
2.41
2.415
2.42
2.425
2.43
2.435
2.44
2.445
head1 mid1 centre mid2 head2
TA-4234
TA-4234

35. 35
• Effective header geometry tobe maintained.
Headers should be properly placed such that the coolant absorbs the
heat generated fromthe rolling process. Itshould beplaced at an ideal
distance.
• Geometrical symmetry tobe practiced.
Geometrical symmetry ensures thatboth sides of the coil are exposed to
similar conditions and prevents any kind of mechanical defects which
can be caused to the coils.
• Equal flows
Equal flows of coolants and lubricants ensurethermal symmetry in the
rolls. Subjecting both sides of the coil to similar thermal conditions.