ISWP PROJECT INTERNSHIP

MENTOR: Mr. VIJAYANT KUMAR

GUIDE : Mr. VINOD KUMAR

PRESENTED BY : KUNAL BHUSHAN VAIDYA

 PROJECT TOPIC
Complete Study Of Rolling Practices
And Recommend For Yield
Improvement In Process and Scrap
Reduction
 Abstract
In a Industrial process which has huge production
rate and demand therefore requires constant
processing with very less time and opportunity for
the improvisation it is very important for a metal
forming process to be free from any defects that can
lower its efficiency. Therefore for a production sector
it is the biggest challenge to design its process with
maximum yield and to avoid the majority of the
losses which can be achieved by repetitive analysis
and constant improvement of the process.
 Acknowledgement
I would like to express my special thanks of gratitude
to my guide Mr. Vinod Kumar sir for their able
guidance and support in completing my project.
I would also like to extend my gratitude to Mr.
Chandan Kumar Sir and Kabita mam for providing me
all the facilities that was required. At last I would also
like to thank our MD Mr. Neeraj Kant sir for giving me
such wonderful opportunity.
Kunal Vaidya
IIT ISM Dhanbad
 INTRODUCTION
This Project has been made to study the
Rolling Processes. It includes concise
information about the Rolling processes and
Yield loss points some methods that can be
applied to reduce the scrap.
For the Rod Mill section nearly 3% to 4% of
the material is lost while processing. This loss
even if looks smaller can add up to a huge
number of lost material and capital.
Pre-Rolling Processes:
1. Billet Yard: Raw
material is stored here
with help of cranes and
placed on Billet bench.

2. Furnace: With the help

of Cold Pusher billets
are placed into furnace
at temperature of 1250
to 1300 degree Celsius.

3. Hot Pusher : Pushes one

Billet by each towards
Stand no.1
 Rolling Processes
• Definition : Rolling is a metal forming process in
which metal stock is passed through one or more
pairs of rolls to reduce the thickness, to make the
thickness uniform, and/or to impact a desired
mechanical property. If the temperature of the
metal is above its recrystallization temperature,
then the process is known as hot rolling. If the
temperature of the metal is below its
recrystallization temperature, the process is known
as cold rolling.
Types of Rolling Mills:

Rolling mill type in the Rod Mill Department is

Tandem Rolling Mill.
ROLLING PROCESSES IN ROD MILL
Functions
•Roughing :
Roughing area mainly focuses on
Reduction of the cross section area by a
huge margin in order to mold the square
cross section into circular it uses RTD guides.
•Intermediate :
Intermediate area has lesser temperature
of the processing material therefore in order
to avoid the cooler ends in shear 9 it goes
through head and tail cut and then a
gradual decrease of diameter
•NTM (Non Twisted Mill):
At this stage main focus is not on reducing
the cross sectional area but on finishing of
the product. Spiral gauging in Case of TMT
bars.
STAND WISE STUDY OF ROLLING PROCESSES
Important Parameters of Rolling Process
• Stand No
• Number of Passes
• Pass Profile
• Stock Size
• Entry Guide
• Exit Guide
• Roll Size
RTD (Roller Twister Delivery Guide)
RE (Roller Entry Guide)
RF (Round Friction)
Stand No Number of Stock Size Entry Guide Exit Guide
Passes and Pass
Profile
1 4 Box 90.6×146 Friction Friction
2 4 Box 62.5×153.5 Friction RTD
3 4 Box 85×88 Friction Friction
4 4 Oval 58×101 Friction RTD
5 4 Round 69×70 RE RF
6 4 Oval 38×84 Friction RTD
7 4 Round 55×49 RE RF
8 6 Oval 31×69 Friction RTD
9 6 Round 41×41 RE RF
10 8 Oval 20.5×51 Friction RTD
11 8 Round 29.5×30 RE RF
12 12 Oval 16.5×38 Friction RTD
13 12 Round 23×23.5 RE RF
14 16 Oval 15×28 Friction RTD
15 16 Round 18.9×19.7 RE RF
Stand No Number of Stock Size Entry Guide Exit Guide
Passes and Pass
Profile

16 2 Oval 10.7x20 Fixed Guide Nozzle

17 2 Round 13.7 820 A/1 Nozzle

18 2 Oval 8.7x16 Fixed Guide Nozzle

19 2 Round 11.1 820 A Nozzle

20 2 Oval 6.7x14 Fixed Guide Nozzle

21 2 Round 8.9 820 A Nozzle

22 2 Oval 5.5x11 Fixed Guide Nozzle

23 2 Round 7.2 820 A Nozzle

24 2 Oval 4.4x8.2 Fixed Guide Nozzle

25 4 Round 5x57 820 A Nozzle

YIELD IMPROVEMENT AND SCRAP
REDUCTION
METHODOLOGY
•Identifying Yield Losses in Total
-Sources of Yield Loss
-Reasons of yield Loss
-Material and capital lost due to it
-Suggestions for Yield Improvement

•Identifying Sources of Scrap

-To know the reasons for Scrap production
-To find and suggest methods for Scrap
reduction
Yield Loss Source

1) Scales Furnace, Stands

2) Cobble Roughing, Intermediate, NTM ,

Roller table
3) Head and Tail end Crop Shear 9 , Shear 15

4) Uncooled Losses (TMT) Water box

5) Billet Bending Billet Yard

6) Rust Losses in Storage Storage Yards

7) Wrong Product NTM , Roller table, Decoiling unit

8) Finished Goods Losses Decoiling Mill

Reasons for the Yield Losses
1. Scales :
Oxidation of the hot billets due air
contact of metal at high
temperature.
2. Cobble :
*Roughing and Intermediate :
- Breakdown due to not proper
selfing
- Guides not aligned properly
(manual mistake)
- Roll Bearings , Roll selfing , Roll
Gauging ( Not proper equipment)
- Equipment damage due to Cold
metal

*Roller Table (Jamming) :

- Roller Table Hooking
- Motor Tripping 0 to 17 no motor
- Bad Quality of Metal
- Laying of Coil in Oval Shape
3. Shear 9 , Shear 15 :
To Avoid the cooled and non
uniform ends which can bring
complications for
further rolling.

4. Uncooled Losses in TMT:

There is time lag inside the
waterbox between water flow and
material passing therefore a
length of material remains
uncooled and hence not having
the quality required for TMT rods.

5. Billet Bending:
While shifting Billets from loaded
trucks to Ground or to the Billet
Bench due to power tripping and
failure in the electromagnet.
Billets are straightened by use of
hydraulic press , which delays the
process and eventually the
process.
6. Rust Losses in Storage:
When Coils are shifted by the
Cranes and kept for storage.
Due to not proper protection
from atmosphere and storage
facilities many coils are
scrapped due to rust.

7. Wrong Product:
If the produced product
doesn’t match the quality
demanded then it is due to
raw material problems or due
to defect in processing

8. Finished Goods Losses:

During Decoiling of the Coils
there is scrap left behind in
some quantities as all TMT
bars are cut in length of 12 m
and also some length of coil is
lost to testing.
 Yield Loss Calculation per Billet
• Weight of one Billet = 1.170 tonnes
• Weight of the Finished Products per Billet/Per
Coil
8 mm Coil Weight per metre = 380-390 gm/m
6 mm Coil Weight per metre = 210-220 gm/m
5.5 mm Coil Weight = 1.140 tonnes
 Losses For 8mm TMT bars

 Total Yield = 96 %
 Losses for 6mm TMT bars

 Total Yield = 95%

 Losses for 5.5 mm Wires

 Total Yield = 97 %
 Production Rate
For May 2022
• Total production 22730 tonnes
• Total Coils = 20480 (cobble not included)

Monthly Production(tonnes)
25000

20000

15000
Monthly Produc-
10000 tion(tonnes)

5000

0
287 317 348 378 409 440 470 501 531 562 593 621
44 44 44 44 44 44 44 44 44 44 44 44
Suggested Remedies for the Yield Losses and Scrap Reduction

• Scales Reduction:
• Cobble:
• Shear 9 , 15
• Water Box Losses reduction
• Billet Bending
• Rust losses
• Wrong Product
• Finished Good Losses
 Scales Reduction
Protective Coatings Increase Material Yield and Reduce Costs
Burning Loss Due to Oxidation

O2 + 2 Fe ↔ 2 FeO

O2 + 4 FeO ↔ 2 Fe2O3
CO2 + Fe ↔ CO + FeO
 CO2 + 3 FeO ↔ Fe3O4 + CO

Characteristics of Protective Coating and its Use

•An anti-scale coating is applied on billets/ingots to be heated before charging them into the furnace.
•Acts as a barrier between the metal and oxygen. Before heating, care is taken to apply a uniform,
impervious coating on the billet to be heated.
•Heat transfer from the heating medium to the metal unaffected by the coating, which also reduces
decarburization on billets during hot-rolling operations.
•No reaction with the steel surface; no release of toxic fumes during use, hot forging or storage; and it
is otherwise nonhazardous.
Protective Coating Increases Yield
   
•   Total reduction in scale = 0.95 mm
•   Percentage reduction in material loss
due to mill scale by using anti-scale
coating = 56.98%
•   Approximately a 70% reduction in
mill scale is achieved by anti-scale
coating in hot rolling of stainless steel.
 
 •   Scale loss of 2.14 kg was observed
on billets without coating.
•   Scale loss of 1.140 kg was observed
on billets with a double layer of
protective anti-scale coating.
•   Percentage reduction in mill scale
loss due to use of protective anti-scale
coating = 47.00%

Add source
 Cobble
• Design of Modified Side Guide System
• Add description

• Signal Analysis of Finishing Mill Parameters

• Study of Process Parameters

 Shear 9 , 15
• Only fractured part of Head and Tail must be removed by the Operator
• Currently Shear15 cuts length of 1.5 m instead of 0.75 m
• Regular maintenance of the Operating systems and sensors.
• Implementation of Machine learning programmes for accurate results

Shear-9 Shear-15
 Water Box Losses eduction

• Separate water supply systems for each water boxes, as shown in line
diagram below
Replacement of Coiling System with Straight Bar System
•It will avoid the extra efforts for the Decoiling Mill
•It will minimize the losses due to uncooled rings as it will become easy for
segregation of uncooled material.
•Once segregated, initial uncooled part can be cooled manually.

 
 Billet Bending
• Avoiding Power Trip in the Billet yard area
 Rust losses
• Development of the Warehouses
• Develop ways to for Rust resistance of FG
 Finished Good Losses
• Shear 9 and 15 cutting length
In order to Avoid FG losses for TMT bars length of Coil can be
adjusted to obtain just at multiple of 12 metres
Billet size = 130 x 130 x 9 m
Stock size at S9 = 41 x 41 weight removed=8 kg(61.86cm)
Stock size at S15 = 18.9 x 19.7 weight removed=2.5 kg(87.3cm)
 Results
• Yield obtained per Billet
22730 x 100/ (20480 x 1.170)= 94.86%
• Yield loss per Billet = 100- 94.86= 5.14%
• Capital loss behind a Billet and Finished Good
5.14/100 x 23,229.35 Rs = 1193.96 Rs
• Monthly Losses Due to Cobble
= 38 x 23,229.35 = 8,82,715.3 Rs
 Conclusion
• The production of the Company is pretty much impressive and demanded by
market for its quality and brand but with the new tools and technologies at
hand it is necessary for such firm to introduce new automation methods in
the operating sector rather than dependence on the manual operating. Eg,
machine learning
• For the machining part flexibility of the process needs to be much more than
its present condition in order for the company to be sustainable according to
the future.
• At present there is much less scope for the testing part of any process at the
company for any new changes. This issue needs to be resolved by developing
some simulation methods Eg, Ansys . Or else with the help of some model
based testing.
• Data collection at various departments regarding Raw material , Production ,
Failures should be widely increased for the purpose of proper analysis.
• Only three types of products are manufactured in Rod mill department when
it has potential to increase a lot making process flexible and decreasing the
time for section change.