Visakhapatnam steel plant

STUDY AND ANALYSIS OF REDUCING OIL CONSUMPTION IN FINISHING MILL
STUDY AND ANALYSIS OF REDUCING OIL CONSUMPTION IN
FINISHING MILL
A report submitted in partial fulfillment of the requirements for the Award of
Degree of
BACHELOR OF TECHNOLOGY
In
MECHANICAL ENGINEERING
By
BONDA VENKATA SWAMY
Roll No.:16ME01038
Under supervision of
RAVI SHANKAR . A
AGM(I/C),WRM-1
SATYANARAYANA . D
Sr. Manager, Mechanical
(Duration: 6th
May, 2019 to 29th
June 2019)
SCHOOL OF MECHANICAL SCIENCES
INDIAN INSTITUTE OF TECHNOLOGY BHUBANESWAR

1
ACKNOWLEDGEMENT
Our first and foremost gratitude is to our Guide Sri. A. Ravi Shankar, AGM(I/C), WRM-1. for
giving challenging project and good support to complete this project.
It is with sincere gratitude that we acknowledge the inputs and support we received from our
mentor D. Satyanarayana, Sr.Manager (Mech) during this project. This project would not
have been completed without their constant positive and encouraging attitude.
Special thanks go to the Employees of Department of Wire Rod Mill for their permission to use
the facilities and equipment available at the Department which aided us to complete this
project successfully.
We would also like to extend our sincere appreciation to the Team working in Morgan Block
Repair Shop (MBRS), at the WRM-1, for their support in the tests carried out for the project.

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INDEX
1. INTRODUCTION OF VIZAG STEEL PLANT, RINL, COMPANY PROFILE
2. MAJOR PLANT FACILITIES
3. WIRE ROD MILL OVERVIEW
4. FINISHING MILL
5. ROLL HOUSING 6- AND 8-INCHES ROLL
6. SUB-ASSEMBLIES OF 6 INCH ROLL AND THEIR FUNCTIONS
7. DISMENTALING OF ROLL HOUSING
8. ASSEMBLY OF ROLL HOUSING
9. READINGS AND PLAYS AND THEIR IMPORTANCE
10. IMPORTANCE AND CHARACTERISTICS OF LUBRICATION OIL MV525(MOBIL
VACUOLINE)
11. PROBLEM DESCRIPTION AND ANALYSIS
12. ROOT CAUSES FOR OIL CONSUMPTION
13. HIGHEST EFFECTIVE ROOT CAUSE
14. REASONS OF ROOT CAUSES
15. SOLUTION

SCHOOL OF MECHANICAL SCIENCES | IIT BHUBANESWAR Page 1
VIZAG STEEL PLANT, RASHTRIYA ISPAT NIGAM LIMITED(RINL)
COMPANY PROFILE:
Rashtriya Ispat Nigam Limited, the corporate entity of Visakhapatnam Steel Plant is a
Navaratna PSE under the Ministry of Steel. Visakhapatnam Steel Plant fondly called Vizag steel.
It is the first shore based Integrated Steel Plant in the country and is known for its quality
products delighting the customers. It is a market leader in long products and it caters to the
needs of diverse Industrial sectors.Most of its income comes from the exports of steel products
to Japan, Germany, United States, Singapore, Dubai, Australia, South American countries and
many more. Vizag Steel Plant has been conferred Navaratna status on November 17th, 2010.
Founded in 1971, the company focuses on producing value-added steel. Equipped with modern
technologies, VSP has an installed capacity of 3 million Tons per annuum of liquid steel and
2.656 million Tons of saleable steel. At VSP there is emphasis on total automation, seamless
integration and efficient upgradation which result in wide range of long and structural
products to meet the stringent demands of discerning customers within India and abroad. VSP
Products meet exalting International Quality Standards such as JIS, DIN, BIS, BS etc.
VSP has many major production facilities such as 3 coke oven batteries of 67 oven each having
41.6 cubic meters volume, 2 Sinter machines of 312 square meters area, 3 Blast furnace of
3200 cubic meters of useful volume, Steel Melt Shop with 3 L.D. converters of 150 Tons
capacity each, six 4 strand continuous bloom casters, Light and Medium Merchant Mill of
710,000 Tons per year capacity, Wire rod mill of 850,000 Tons per year capacity, Medium
Merchant & Structural Mill of 850,000 Tons per year capacity.
Extensive facilities have been provided for repair and maintenance as well as manufacture of
spare parts. A Thermal Power Plant and an Air Separation Plant also form part of the plant
facilities.
Modern technology has been adopted in many areas of production, some of them for the first
time in the country. Among these are Selective crushing of coal, Pneumatic Separation of Coal,
7 meter tall coke ovens, Dry quenching of coke, on-ground blending of Sinter base-mix,
conveyor charging and bell less top for blast furnace, cast house slag granulation for blast
furnace, gas expansion turbine for power generation utilizing blast furnace top gas pressure,
hot metal de-sulphurization, extensive treatment facilities of effluents for ensuring proper
environmental protection, computerization for process control and sophistication in high
speed and high production rolling mills.

MAJOR PLANT FACILITIES
Major Departments in VSP and their roles
 Raw Material Handling Plant (RMHP)
 Coke Ovens & Coal Chemical Plant (COCCP)
 Sinter Plant
 Blast Furnace (BF)
 Steel Melt Shop (SMS) & Continuous Casting Department (CCD)
 Rolling Mills
1. Light & Medium Merchant Mill (LMMM)
2. Wire Rod Mill (WRM)
3. Medium Merchant & Structural Mill (MMSM)
4. Special Bar Mill (SBM)
5. Structural Mill (SM)
Raw Material Handling Plant (RMPH):
VSP requires quality raw material like iron ore, fluxes, coal etc. The vital function of receiving
the materials from various sources and feeding them to various departments is served by the
RMPH.
The unit is provided with elaborate unloading, blending, stacking & reclaiming facilities.
Coke Ovens & Coal Chemical Plant (COCCP):
Coal is converted into coke by heating the prepared coal blend charge in the coke ovens in the
absence of air at a temperature of 1000oC-1050oC for a period of 16/19 hours. The volatile
matter of coal liberated during carbonization is collected in gas collecting mains in the form of
raw coke oven gas passing through stand pipes and direct contact cooling with ammonia liquor
spray. The gas cooled from 800oC to 80oC is drawn to Coal Chemical Plant by Exhauster. The
residual coke is pushed out of the oven by pusher car through a guide into coke bucket. The
red-hot coke is taken to coke dry cooling plant for cooling.
The main by-product in the process of coke making is crude coke oven gas and this has a lot of
valuable chemicals. Coal Chemical Plant Recovers Ammonia (NH3), Tar and Benzol from

CO-Gas. The primary by-products from Crude CO Gas are Ammonium Sulphate (NH4)2SO4,
Crude Tar, Crude Benzol and cleaned coke oven gas. The cooled coke from CDCP (Coke Dry
Cooling Plant) is separated into 3 fractions, BF Coke i.e. +25-70 mm, which is sent to Blast
Furnaces, Coke Breeze i.e. +0-15 mm, which is sent to Sinter making and nut coke i.e., +15-25
mm, which is also used in the Blast Furnaces.
Facilities:
There are 4 batteries, each having 67 ovens.
The volumetric capacity of each oven is 41.6 m3.
Dry Coal charge /Oven is 32 tons.
Salient Features:
Largest and technologically unique Coke Oven Batteries in the country at the time of
commissioning.
7-meter-tall coke ovens batteries.
Selective crushing of coal to improve the coke quality.
100% Dry Quenching of coke using Nitrogen gas.
Power generation, from the waste heat recovered, at BPTS (Back Pressure Turbine
Station).
Capacity:
Production capacity (for 4 Batteries) – 2.475 Mt of BF coke per annum.
Sinter Plant:
Sintering is an agglomeration process of fine mineral particles into a porous mass by incipient
fusion caused by heat produced by combustion within the mass itself. Iron ore fines, coke
breeze, limestone and dolomite along with recycled metallurgical wastes are converted into
agglomerated mass at the Sinter Plant, which forms 70-80% of iron bearing charge in the Blast
Furnace. The vertical speed of sintering depends on the suction that is created under the grate.
At VSP, two exhausters are provided for each machine to create a suction of 1500-1600 mm
water column under the grate.
Facilities:

Sinter machine-1 with 378 M2 grate area (after Modernization)
Sinter machine-2 with 312 M2 grate area.
Sinter Machine-3 with 408 M2 grate area.
Salient Features:
Base mix (homogeneous mixture of all raw materials) blending yard with six beds each of 1,
10,000 tons storage capacity.
M/C-1&2
Sinter Machine-1 (after modernization) is provided with Chamber type Ignition Furnace
with roof mounted energy efficient burners. Machine-2 is provided with an ignition
furnace of horizontal burners.
Sinter Bed Height 650 mm for M/C-1 (after Modernization) & 500 mm for M/C-2.
Straight Line Sinter Cooler.
Sinter Heat Recovery Power Plant (SHRPP) with a capacity of 20.6 MW electrical power
generation by utilizing waste heat recovered from Sinter Coolers of Machine 1 & 2
M/C-3
Bed Height 700 mm.
Chamber type Ignition Furnace with roof mounted energy efficient burners.
27 m long extended hood with hot air supply through 4 feed points.
Circular Sinter cooler with waste heat recovery system.
Lime addition at Mixing and Nodulizing Section of Sinter Machine building.
Production Capacity:
Sinter Machine – 1 : 3.640 MT of Gross Sinter per annum (after Modernization)
Sinter Machine – 2 : 2.628 MT of Gross Sinter per annum.
Sinter Machine – 3 : 3.611 MT of Gross Sinter per annum.

Blast Furnace (BF):
Iron is produced in the Blast Furnace by smelting iron bearing materials with the help of coke
and air. The solid charge materials like sinter, sized iron ore, coke etc. are charged in the
vertical shaft of the Blast Furnace from top and hot air blast is blown through tuyeres located
at the bottom. The oxygen present in hot air combines with the carbon of coke and generates
heat and carbon monoxide (reducing agent). The reducing gases, while ascending upwards
comes into contact with the descending charge materials. Eventually the charge gets reduced
and hot metal, slag and BF gas are produced. Hot metal and slag are tapped from tap hole. The
Blast Furnace gas which comes out from top of the furnace is cleaned and used as fuel in the
plant.
Facilities:
Three Blast Furnaces of 3800 m3 useful volume each.
Salient Features:
BF-1 & 2
New generation Paul-Wurth "Bell-Less" Top with conveyor charging.
BF Cooling elements (Cast Iron Staves & Copper Staves).
High heat zone copper staves.
Double compensator tuyeres, with PCI injection facility and extended tuyere platform.
Circular type flat cast house with full castable runner system.
Hydraulic Drilling Machine, Mud Gun, Manipulators.
Silencer to bin pressure relief.
New scrubber with annular gap element for better gas cleaning.
HMI based control room.
Equipped with above burden temperature Probes.
Automation with PLC in BF-1 and PCS in BF-2.
Pulverized Coal Injection system.

BF-3
New Generation Parallel Hopper Bell Less Top.
BF Cooling elements (Cast Iron Staves & Copper Staves).
Flat Cast house Equipment (by TMT).
INBA Slag Granulation system.
Annular Gap Scrubber.
Pulverized Coal Injection system.
Hot Stoves (internal combustion chamber).
Automation with DCS.
Capacity:
Production Capacity - 7.5 MT per Annum for shop.
- 2.5 MT per Annum for BF-1, 2 & 3 each.
Steel Melt Shop (SMS) & Continuous Casting Department (CCD):
Steel is made in steel melting shop in the refractory lined vessels called LD Converters by
blowing oxygen through the hot metal bath. While iron making is a reduction process, steel
making is an oxidation process. The oxygen reacts with impurities like carbon, silicon,
phosphorous, Sulphur etc. present in hot metal to produce steel. No external fuel is required as
the silicon & carbon releases huge amount of heat energy. Also, the carbon reaction releases
large quantities of gas rich in carbon monoxide along with huge amount of dust. The gases
released from the converter are collected, cooled, cleaned and recovered for use as fuel in the
steel plant. The entire molten steel at VSP is continuously cast at the radial type continuous
casting machines resulting in significant energy conservation and better-quality steel. 100%
Continuous casting on such a large scale has been conceived for the first time in India.
Facilities:
SMS-1:
Three LD converters (modernized with increase in volume to 150 cum. each along with
DOG House facility).
6 nos. of 4 - Strand Continuous Bloom Casting machines.

SMS-2:
Three LD Converters of 150 cum. volume each.
1 no. of 6- Strand Continuous Billet- cum- Round caster.
2 nos. of 6- Strand Continuous Billet casters.
1 no. of 5-strand Continuous Billet-cum-Round caster.
Hot Metal Desulphurization Plant (HMDP).
DOG House.
RH Degasser.
Salient Features:
100% Continuous casting of steel.
Converters gas cooling, cleaning and recovery systems.
Computerization of the converter process.
Capacity:
Production Capacity
SMS-1: Original Installed Capacity is 3.0 MT of Liquid Steel per annum & 2.82 MT of CC
Blooms per annum. After Modernization of all the 3 converters, capacity is enhanced to
3.5 MT of Liquid Steel & 3.29 MT of CC Blooms per annum.
SMS-2: 3.8 MT of Liquid Steel per annum & 3.7 MT of CC Blooms/Rounds per annum from
Converters-D, E & F.
Rolling Mills:
The cast blooms from CCD are sent to high speed rolling mills i.e. LMMM, WRM and MMSM.
Light & Medium Merchant Mill (LMMM)
The cast blooms from continuous casting department are heated and rolled in the two high
speed and fully automated rolling mills namely Light & Medium Merchant Mill (LMMM) and
Medium Merchant & Structural Mill (MMSM). The billets produced in LMMM are further rolled
in Bar Mill / Wire Rod Mill (WRM). The finished products include wire rods & long products
like reinforcement bars, rounds, squares, flats, angles, channels, billets etc.

Blooms from Continuous Casting Division are rolled into billets, some of which are sold and
rest are sent to Bar Mill/WRM. The continuous two-line Bar Mill comprises of 8 Stand Double
Strand roughing train, 2 nos. of 4 Stand Single Strand intermediate train & 2 nos. of 4 Stand
Single Strand finishing train. Loopers are provided in between the finishing stands for tension
free rolling in order to obtain good surface quality and tolerances. Housings are of closed top
type. Roll necks are mounted in anti-friction bearings.
Facilities:
Breakdown Mill
7 Stand Break-Down Mill.
Bar Mill
8 Stand Roughing Mill (2 Strand rolling).
2 Stands 4 Single Strand rolling Intermediate Mill.
2 Stands 4 Single Strand rolling Finishing Mill.
Salient Features:
Evaporating cooling systems in Rolling Mill furnaces.
Computerized Rolling Mill.
Tempcore cooling process facilitating high strength with good bendability and weldability.
Capacity:
A Mill of 0.710 MT per annum.
Wire Rod Mill (WRM)
WRM-1
The Mill is high speed 4 strand No-Twist continuous mill designed to produce 8,50,000 Tons of
wire rod coils per year. Rolled billets of 125 mm x 125 mm square cross section, length ranging
from 9.8 m to 10.4 m and weighing approximately 1250 kgs are used. The mill is designed to
roll steel stock of 0.9% max. carbon content.
WRM-2
The Mill is designed to produce 6,00,000 tons per year of rounds in coil form. The Mill is
designed to roll low, medium and high carbon steel, case hardening steel, cold heading quality

steel, electrode steel, spring steel, bearing steel and free cutting steel. The mill shall use
continuous cast billets of 150 mm X 150 mm square cross section, 12 m length and weighing
2100 kgs approximately, are used as input material.
Facilities:
WRM-1
7 Stand Roughing Mill (4 Strand rolling).
6 Stand Intermediate Mill (4 Strand rolling).
4 singe-strand 2 Stand Pre-finishing Mill (Single Strand rolling).
4 single-strand finishing blocks with 10 stands 16-25 each (MORGAN BLOCK-Single Strand
rolling).
WRM-2
6 - Stand Single strand Fast Roughing Mill.
2 - Strand insulated Roller Table.
6 Stand Intermediate Mill - I.
4 Stand Intermediate Mill - II.
2 Strand 2 - Stand pre-finishing train.
2 Strand 8 - Stand No-Twist blocks.
2 Strand 4 - Stand Reducing and Sizing Mill (RSM).
Salient Features:
Highly automated and computerized Rolling Mill.
Controlled cooling of Wire Rods, by 'Stelmor' process with Opti mesh technology giving
high strength and good ductility.
Closed loop control for Laying temperature with Morgan patented METCS (Morgan
enhanced temperature control system) in WRM-2 to enhance Metallurgical properties.
Capacity:
WRM-1: 0.85 MT per annum.

WRM-2: 0.60 MT per annum.
Product-Mix:
WRM-1
Plain Rod - 5.5 mm to 12.7 mm diameter. However, sizes up to 14 mm are also being rolled
presently.
Rebar - 8mm, 10mm and 12mm diameter in coil form.
WRM-2
Plain Rod - 5.5 to 20.0 mm in step of 0.5, Plain rod Día 20.64 mm can also be rolled in
future.
Medium Merchant & Structural Mill (MMSM)
The Medium Merchant and Structural Mill (MMSM) is one of the modern rolling mills of
Visakhapatnam Steel Plant. This is a single strand continuous mill having production capacity
of 8,50,000 tons per year. The important feature of this mill is that Universal beams (both
parallel and wide flange) have been rolled for the first time in India using Universal stands.
Parallel flange beams have an advantage over conventional beams because, for the same
weight, the section is stronger and stiffer due to greater moment of inertia and higher radius of
gyration.
Facilities:
8 Stand Roughing Mill (4 high horizontal, 2 vertical and 2 combinations).
6 Stand Intermediate Mill (2 high, 2 vertical and 3 universal).
6 Stand Finishing Mill.
Salient Features:
Evaporating cooling systems in Rolling Mill furnaces.
Sophisticated, high speed rolling mills with computerized controls.
Capacity:
A Mill of 0.85 MT per annum.

Special Bar Mill (SBM)
The Mill is designed to produce 7,50,000 tons per year of plain rounds in straight length and in
coil form by using an input of Continuous cast billets of 150 mm x 150 mm x 12 m and
weighing approximately 2050 kgs. The mill is designed to roll medium and high carbon steel,
case hardening steel, cold heading quality steel, electrode steel, spring steel, bearing steel and
free cutting steel.
Facilities:
6 Stand Roughing Train.
6 Stand Intermediate Train.
6 Stand Pre-Finishing Train.
3 Nos. Stand Finishing Train (Sizing train).
Pendulum shear, Flying shear 3 no’s and dividing shear.
Controlled cooling facilities.
Straight Form: Chain transfers, Cold Shear, Bundling Facilities and Strapping machines.
Coil Form: Garret coilers, Cooling conveyors, Hook conveyors, Compacting and Strapping
Machines.
Salient Features:
Continuous Mill consisting of 21 stands of housing-less design.
20 - 45 mm size in straight & coil form (Reduced wastage for end user).
Free size rolling (Customized sizes with closed tolerances).
Low temperature rolling for finer grain structure.
Online automatic measuring gauge for better quality control.
Automatic bar Bundling & Strapping machines for packaging of finished products.
Capacity:
0.75 MT per annum. The enhanced production capacity is 0.90 MT per annum.

Product Mix:
Round Form Outputs:
Rounds - 20 mm to 45 mm diameter (with a special provision to roll 16 mm to 18 mm).
Coils - 2.0 tons (as per billet weight).
Straight Form Outputs:
Straights - 12.0 m bundle with 6 straps.
Structural Mill (SM)
The Mill is designed to produce 7,00,000 tons per year of structural section in straight length in
approximately 3733 rolling hours and 8,50,000 tons per year of structural sections in straight
length in approximately within 4533 rolling hours.an input of Continuous cast cold bloom of
200 mm x 200 mm x 12 m and weighing approximately 3760 kgs.
Facilities
Walking beam re-heating furnace, 200 tph capacity with cold storage charge, and relevant
charging and discharging services.
Furnace exit area with pinch roll and high-pressure water static descale.
Exit furnace table for the feeding of continuous rolling mill.
Continuous rolling mill composed of 17 rolling stand "housing less type" namely
1. Roughing mill composed of 7 stands arrange in H-V disposition.
2. Intermediate mill composed of 5 stands arranged either in H or
H/V/U or H/U disposition.
3. Finishing mill composed of 5 stands arranged either in H or H/V/U or H/U
or H/V disposition.
A crop type start/stop crank shear arranged after stand no. 7.
A crop type start/stop rotary shear arranged after stand no. 12.
Dividing shear for multiple length cut after stand 17.
Double sided 90 m long cooling bed.

Straightening machine.
84 m long batching area.
Three saws for cutting to length in each line.
Stacking, strapping, weighting and collection stations.
Salient Features:
Continuous Mill consisting of 17 stands of housing-less design.
Mode Optimization for cut length of bars.
On line automatic measuring gauge for better quality control.
Automatic bar bundling & strapping machines for packaging of finished products.
Basalt Rock Liner in the scale Flume tunnel to prevent wear out of the base of the tunnel.
Minimum tension control and tension free (loop) control.
Optimized roll pass design for all product.
Start/Stop type flying shears along the mill for emergency chopping of rolled stock.
Capacity:
Mills: 0.70 MT per annum. The enhanced production capacity is 0.85 MT per annum.
Starting Material:
Continuous cast cold bloom: 200 x 200 x 12,000mm - weight 3,760 kg.
Product Mix:
Beams: ISMB 100,125,150 mm; ISJB 150, 175 mm; ISLB 100, 125, 150 mm.
Channels: ISMC 75, 100, 125, 150, 175 mm; ISJC 100, 125, 150, 175 mm.
Angles: 55, 60, 65, 75, 80, 90, 100 mm.
Flat: 70 to 180 mm (thickness: 8 to 30 mm).
Special sections like
Round : 45 to 95 mm

Squares : 45 to 80 mm
HE (columns with parallel flanges) : 100 to 120 mm
IPN (Beams with tapered Flanges) : 100 to 180 mm
IPE (Beams with parallel flanges) : 100 to 180 mm
TEE : 60 x 60 x 7 mm
Unequal angles : 80 x 50, 90 x 60, 125 x 75 mm
WRM OVERVIEW
The mill has 4 zone combination type reheating furnaces (walking beam cum walking hearth)
of 200t/hr. capacity for heating the billets received from the billet mill of LMMM to rolling
temperature of 1800°c.
The mill produces rounds in 5.5 – 12.7 mm range plain coils and re-bar’s in 8, 10&12mm range
coils.
The annual capacity of the WRM is 850,000 tons of finished wire rods by 3 shift operation and
specified product mix.
The four- strand wire rod mill consists of
 Four –strand roughing mill with 7 stands.
 Four-strands intermediate mill with 6 stands.
 Four single-strand intermediate blocks with 2 stands.
 Four single-strand finishing blocks with 10 stands.
Fig. 1

Final Product of WRM
Fig. 2
Billets Coils
Fig. 3

ROLLING OF WIRE RODS IN WRM
FINISHING MILL
The finishing mill usually has five to seven finishing roll stands, which reduce the thickness of
the transfer bar down to the gauge required. The rolling speed is set to allow the last stand to
perform the final reduction at the finishing temperature, between 820 deg C to 900 deg C, so as
to achieve certain mechanical properties in the hot rolled strip. The finishing mills roll the
transfer bar through all the finishing stands at once. The hot steel is quite fragile as it is rolled
and tension between the finishing mill stands must be closely controlled at very low levels in
order to avoid stretching or tearing the strip.
Adjustments are made as necessary to ensure the strip threads properly through each of the
mills without looping up and folding over or stretching and tearing apart. The position of each
roll is fed back to the finishing mill’s sophisticated automation system which, along with
information from the load cells that monitor rolling force and from the X-ray gauge measuring
final strip thickness, work to smoothly adjust the roll gaps and speeds to maintain stable
rolling of strip to the necessary thickness in spite of the temperature variations present in
every bar.
Once the bar is threaded between each successive pair of mills, a looper engages the strip to
monitor the tension between the stands. The loopers arranged between the finishing stands of
the Mill safeguard correct mass flow control and hence contribute to the stable rolling of
finished strip down to the final thickness of the strip.
The inter-stand facilities are vitally important for the production of hot rolled strip with top
surface quality. Important equipment includes (i) entry and exit guides, (ii) work roll cooling
system, (iii) anti peeling device, (iv) roll gap lubrication system, and (v) inter-stand cooling and

descaling systems. Close interplay of all these facilities is a must to achieve an optimal result.
The strip guide areas are designed so that all wearing parts can be replaced quickly. The
cooling efficiency is improved by optimized selection and arrangement of nozzles.
Since each transfer bar spends approximately one minute in the finish mill, from head to tail,
the temperature of the steel going into the finishing stands is significantly lower, perhaps 100
deg C, by the time the tail-end is rolled as compared to the head-end. Consequently, once the
first 150 m of the strip has been rolled at the thread speed and a down coiler has been
threaded.
Finishing Mill mainly consists of
1. Finishing Block
2. Cooling control
3. Pinch Roll
4. Laying head
Finishing block: The finishing Block contains two rolls along with shafts, which reduce the
thickness of the transfer bar down to the gauge required.
Cooling control (Water box): After exiting the finishing mills, the strip is carried down by an
individually-driven rolls through banks of low-pressure, high-volume water sprays that cool
the red-hot strip to a specified coiling temperature between 400 deg C and 900 deg C and into
down coilers. Side guides on either side of the run out table seek to keep the strip’s head-end
pointed at the coilers; the final section of guides in front of each coiler adjusts to match strip
width and features a pneumatic quick-close system that allows the operator to center the strip
head-end as coiling begins.
Pinch Roll: pinch rolls that catch the strip head-end and establish tension across the run-out
table and back to the finishing mills. The head-end is deflected by a gate down to the mandrel
associated with the coiler and is guided around the mandrel (a cylindrical rod around which
metal or other material is forged or shaped) by pneumatically-actuated wrapper rolls linked by
aprons.
Laying head: the coil from the mandrel and places it in position for transport to the automatic
binding machine.

ROLL HOUSING
GENERAL DESIGN CONCEPT:
The roll stand proper comprises two ring-type rolls which are carried by the two overhung roll
shaft extensions. The roll shafts run on plain bearings (cleveite bearings) which, in turn, are
incorporated in eccentric cartridge assemblies. The eccentric cartridge assemblies can be
rotated inside the bores provided in the roll housings. Rotation of the eccentric cartridges
inside the housings bores results in the variation of the roll parting. Actuation of the roll
parting adjustment mechanism is ensured via two roll parting adjustment screws
interconnected with each other.
The 6inch roll shafts are provided with hardened and ground helical tooting gears and features
26 teeth which are meshing with mill pinions featuring 31 teeth. The 8inch roll shafts, on other
hand, feature 29 teeth and are meshing with mill pinions provided with 26 teeth.
The mill pinions are supported in bearings incorporated in the bevel gear unit. Accordingly, the
gear meshing point mill pinion to roll shaft gear unit so called "Interface".
The axial thrust generated by the roll shafts is carried by a set of angular contact ball bearings
which are retained in position via so called labile disk affording virtually end-play-free
mounting of the bearings involved. Due to the extremely small end play in the ball bearings
itself, the roll shafts are axially located with a high amount of accuracy. Such accuracy, however,
is a basic requirement with a view to allowing close-tolerance wire rod to be rolled.

SUB-ASSEMBLIES OF 6 INCH ROLL HOUSING AND THEIR FUNCTIONS
1. Eccentric Cartridge
2. Plain bearings (Cleveite bearings)
3. Thrust bearings (set of angular contact ball bearings)
4. Flingers
5. Twin lip sleeves
6. Lemifex disk
7. Seal plate
8. Front wall
10. Housing rear
11. 'O' Rings
12. Locking bar and Sims
13. Roll sleeve
1. Eccentric cartridge: It holds the pair of plain bearings in position and ensure certain
minimum and maximum position of the shaft.
Fig. 4
Eccentric Cartridge with plain bearing Eccentric Cartridge without plain bearing
2. Plain bearings (Clevite bearings): The plain bearing consists of two semi-circular basic

elements. The inner diameter of the basic element carries a lining of Copper-Lead-based alloy.
This lining is covered by a thin layer of Babbitt metal of a thickness of 0.05mm.
Plain bearings are placed in between the Eccentric cartridge and Roll shaft to avoid friction
between them and to support a load and guide moving parts. When a bearing is supplied with
adequate oil, a pressure is developed in the clearance space when the journal rotates about an
axis that is eccentric with the bearing axis.
Lubrication oil is supplied over the plain bearing through bores and groove provided to the
bearing.
Fig. 5
3. Thrust bearings: Angular contact ball bearings are able to absorb both radial and axial
loads and are also suitable for high speeds. Single-row angular contact ball bearings, however,
can absorb axial loads in just one direction only, with the result that in many circumstances
they are paired with a second bearing. The arrangement of the bearings in relation to each
other influences the load absorption and axial clearance characteristics.
The axial thrust generated by the roll shafts is carried by a set of angular contact ball bearings.

Fig. 6
4. Flingers: It is used to hold the position of the Twin-lip seal.
Fig. 7
5. Twin-lip Seal: The Twin-lip Sleeves consists of two lip on both sides which resist the ingress
of cooling water in the lube oil. This is one of the reasons causing contamination of the lube oil.
Fig. 8
6. Lamiflex disk: The Lamiflex disk consists of two relatively thin steel washers holding a

bounded layer of elastic material between them.
When using Lamiflex disks on bevel gear and roll shafts, the outer race of the thrust bearing is
clamped in axial direction with a specified amount of torque. In axial direction, the thrust
bearing is installed without any end play when using Lamiflex disks (Rigid mounting).
Fig. 9
7. Seal Plate: It ensure the proper position of the Twin-lip sleeve in roll housing.
Fig. 9.Seal plate with Twin-lip seal
Fig. 10

8. Front wall and Rare housing: It holds and cover all the parts and sub-assemblies in a
position.
Fig. 11
Fig. 12
9. O-Rings: are one of the simplest types of seals where they have a circular cross-section, and
they are typically used for preventing leakage between components. The O-rings are placed
inside the groove.
Fig. 13

10. Locking bar and Sims: This is used to lock the rolling shafts.
Fig. 14
13. Roll Sleeve: It is with cylindrical shape outer surface and slightly cone shape inside surface.
Which is used to fix the Roll (Ring) to the Roll shaft by means of tight
Fig. 15
DISMENTALING OF ROLL HOUSING
INSTALLATION AND REMOVAL OF ROLL HOUSINGS FROM THE MILL
The roll housings of the No-Twist Finishing Mill are designed as interchangeable units ensuring
fast and easy removal from the mill as well as fast and easy reinstallation.
Roll housings are removed for reconditioning for three main reasons
1. within the scope of regular and periodic maintenance schedules.
2. Because of a wearing problem on the roll shaft taper.
3. Because of failure of the roll shaft main bearing (failure due to contaminating oil, bearing

running hot)
All roll housings are given a serial number by SMS. In this connection, it would be an advantage
to work out a Check List for allowing the in-process performance of the roll housings to be
followed up and supervised. Keeping an eye on the in-process performance of the various roll
housings installed in the mill on the basis of the data entered in these Check Lists will then
allow the maintenance personnel in charge to establish reasonable and appropriate roll
housing changing intervals.
Each roll housing is fastened to the corresponding mounting face of the bevel gear housing
means of 12 hexagon head cap screws with specification M20 and, moreover, positively located
and held in position by two dowel pins each. The two dowel pins provide perfect positioning of
the system with a view to ensuring accurate meshing between mill pinion and roll shaft
toothing, follow the below figure. Indicated with two arrows.
Fig. 16
REMOVAL OF ROLL HOUSING FROM THE MILL
The mill drive must have been shut down and lube oil supply to the mill must have been
blocked off.
a. Run power-operated cobble guard door to raised position (It is not necessary in this case
to dismantle the cobble guard door).
b. Disconnect hose line connection to roller entry guide.

c. Remove 10 of the 12 hexagon head cap screws with specification M20 on roll housings
being inclined in downward direction and all 12 hexagon head cap screws on roll housings
being inclined in upward direction.
d. Attach hook-type roll housing lifting rig with the help of four hexagon head cap screws
with specification M20. Attach to top edge of housing front wall, in the event of upper
housings (housings inclined in downward direction) as per Figure given below.
Fig. 17
e. Attach roll housing lifting rig to bottom edge of roll housing , in the event of lower housings
(housings inclined in upward direction) follow the figure given below.
Fig. 18
f. Use a rope sling for attaching lifting rig to crane hook. Take in to account that due to left-
and right-hand design concept of No-Twist Finishing Mills involved center of gravity of roll

housing is either on left or on right side as referred to roll housing. Possibility of offset
connection of lifting slings is provided for this purpose on lifting trunnions of lifting hook
assembly.
g. The weight of roll housing is approx. 550kgs. Normally, the crane is not an appropriate tool
for the removal and installation of roll housings. A manually operated chain hoist
connected to the crane hook allows the roll housing to be better handled with the require
amount of "sensitiveness".
h. Remove the two remaining hexagon head cap screws of upper roll housings (housings
inclined in downward direction) at this stage.Move chain hoist or crane, respectively, step
by step in order to obtain the required 45-degree angle movement when housing slides
down from the two dowel pins. Removing of roll shafts from meshing with mill pinions has
to be done utmost care.
i. The lifting hook assembly was designed so as to maintain the roll housing in the specified
45-degree angle position. Look at the below figure for better understanding of housing
lifting rig. In the Fig. 20.
j. protecting cap arranged on the tilting bracket is provided in close proximity of the
No-Twist Finishing Mill so as to hold the roll housing upon removal thereof from the mill.
The protecting cap is to be positioned in accordance with the position of the roll housing
being removed from the mill. Please refer below fig. 19.
Fig.19

Fig. 20
lifting hook

REINSTALLATION OF A ROLL HOUSING TO THE MILL:
1. Clean the roll housing and bevel gear housing properly and apply a thin coat of oil. The four
'O' rings 28x2.5mm arranged at the point of transition for oil feed from bevel gear housing
to roll housing should be lock-bonded in position on the bevel gear housing in order to
prevent them from dislodging taking into account that such dislodging might result in the
'O-ring’s being crushed between the contact faces involved when installing the roll
housing.
2. Attach hook-type lifting rig to roll housing and connect to chain hoist or crane, respectively.
When re-installing roll housing, take care that roll housing is installed in a way that, first of
all the pilot-type fitting keys slide into the corresponding key-ways and that, thereupon,
the two fitting dowels are inserted in the corresponding bores of the bevel gear housing.
3. Move roll housing slowly into position maintaining housing at an angle of 45 degrees.
when roll shafts are about to get into mesh with mill pinion toothing, it may be necessary
to rotate roll shafts slightly for causing the toothings to get into mesh.
4. Insert and tighten hexagon head cap screws. Proceed according to sequence adopted for
removal.
5. Disconnect hook-type lifting rig. Insert remaining two hexagon cap screws (bores are
available after removal of lifting rig) and tighten.
6. Roll housing installation is then completed and, accordingly, the No-Twist Finishing Mill
can be prepared for the following rolling program by the installation of the various mill
guides, rolls etc.
DIS-ASSEMBLY OF ROLL HOUSINGS
Dis-assembly of roll housings for maintenance or reconditioning must be carried out in a
properly clean workshop off the mill proper.
Position housing rear side on housing dis-assembly table. Follow the below fig. 21.
Fig. 21

Remove the following components from roll housing front side:
a. Front seal plate inclusive of seals, Flingers and Water-cooling pipes (cooling
headers).
b. Lift the roll housing with the help of crane by means of eye screw fork inserted to the front
plate and placed the roll housing on the lifting screw jacks provided in the roll house
dis-assembly table. Look at the arrow in the following figure.
Fig. 22
c. Remove plug screws and both cylindrical dowels. Thereupon, remove the five hexagon
head cap screws arranged between front plate and rear part of the housing and lift front
part with due care vertically off rear part of housing.
d. Remove locking bars on housing rear part.
e. Rotate roll parting adjustment screws so as to run fork-type elements associated with
eccentric cartridges to outermost position.
f. Remove fastening screws of both bearing housings of roll parting adjustment screw and
dismantle bearing housings together with adjustment screw and bronze nut.
g. Lift eccentric cartridge sub-assembly vertically out of the housing using a lifting eye screw
as per below figure.
h. Thereupon, remove second eccentric cartridge from roll housing.

Fig. 23
DISASSEMBLY OF ECCENTRIC CARTRIDGE SUB-ASSEMBLIES
Place the complete eccentric cartridge sub-assembly onto dis-assembly table and proceed as
follows:
1. Remove self-locking socket head cap screws on retaining ring and remove retainer
together with outer Lamiflex disk. Thereupon, slacken self-locking slotted nut using
dis-assembly tool and remove accordingly. Remove equally ring with lock bonded fitting
keys.
2. screw extracting device to rear side eccentric bushing and force roll shaft with due care out
of thrust bearing using thrust screw provided for this purpose. Operation involved must be
carried out with utmost care in order not to damage Lamiflex disk and ball bearing
assembly. Thereupon, remove retainers on the two cylindrical dowel pins 16mm dia, pull
dowels out and remove the socket-head cap screws securing the two eccentric cartridge
halves against each other. Lift rear side cartridge half with due care and, thereupon, lift roll
shaft out of front side cartridge half using the lifting eye nut.

Fig. 24
REMOVAL OF A PLAIN (CLEVITE BEARINGS) FROM ECCENTRIC CARTRIDGE
a. Removal of a roll-side plain bearing is relatively easy since the bearing is not retained by a
contact shoulder. For forcing the bearing out of the bore, a punch of adequate size is to be
used.
b. Removal of the drive-side bearing, on the other hand, is carried out using a specially
designed clevite extractor.
c. Check eccentric cartridge bores for burrs and other damage after removal of the plain
bearings.
INSTALLATION OF A PLAIN (CLEVITE ) BEARING
The bearing bush wall thickness is no more than approx. 3.2 mm. Pushing the split bearing
bushes into the bores of the eccentric cartridges involves the risk that the walls of the bush are
susceptible to bulging under pressure or that pick-up occurs on the bush due to the shearing
effect existing between bearing bush and eccentric cartridge bore. In order to counteract this,
we have two methods.
Method1: the eccentric cartridge is preheated whereas the bearing bush is chilled prior to
installation.
Method2: Freezing the bushes together with guide sleeves, in a special deep-freezing cabinet to
-90 degree Celsius.

INSTALLATION OF ROLL-SIDE PLAIN (CLEVITE) BEARING
1. Install bearing bushes in guide sleeve.
2. Put guide sleeve together with bearing bushes into deep-freezing cabinet and deep-freeze
to -90 degree Celsius.
Start installing bearing bushes in front-side eccentric cartridge after bushes and guide sleeve
have been frozen down to specified temperature and proceed as follows.
Slide eccentric cartridge over stop bar. Position frozen guide sleeve with pilot bore in sleeve on
top of eccentric cartridge.
a. Force bearing through guide sleeve into eccentric cartridge until bearing is seated on stop
bar. Check to make sure that faces of bearing halves are flush with face of eccentric
cartridge.
b. Check bearing bushes for correct location of parting lines.
c. Check oil bores in bearing bush and eccentric cartridge for unobstructed flow of oil.
d. Check plain bearing bore, bore must be free from any kind of damage.
Fig. 25

INSTALLATION OF DRIVE-SIDE PLAIN (CLEVITE) BEARING
1. Install bearing bushes in guide sleeve.
2. Put guide sleeve together with bearing bushes into deep-freezing cabinet and deep-freeze
to -90 degree Celsius.
3. Force bearing bushes through guide sleeve into eccentric cartridge to a position where
bearing bushings are seated on contact shoulder within eccentric cartridge.
4. Check oil bores for free and unobstructed flow.
5. Check plain bearing bore for perfect surface condition prior to proceeding with assembly.
Fig. 26

ASSEMBLY OF THE ROLL HOUSING
a. Clean roll shaft and check accordingly. Check toothing for finding out nature of wear, if any.
Checking the bearing seats as to scoring and burrs is of special importance.
b. If light scoring exists, same has to be rubbed off on a lathe by means of fine-grit crocus
cloth. Bearing trunnions exhibiting a large number of scoring or deep scores, on the other
hand, have to be reconditioned by chrome-plating. The bearing seats must retain the
appearance they had at the time when they were supplied. At speeds exceeding 10000RPM
you cannot afford to tolerate shaft or bearing problems.
c. Proceed as follows after parts involved have been cleaned in a rinsing tank as follow the
figure below.
Fig. 27
d. Insert roll-side eccentric cartridge half with parting line on top in assembly table bore.
Inadvertent rotation of eccentric cartridge half is blocked with the help of locking pin in
assembly table.

Fig. 28
e. Attach lifting nut to roll shaft and position guide sleeve on taper side of roll shaft This
guiding element prevents the shaft from damaging the plain bearings while being lowered.
Thereupon, apply a thin layer of oil to guiding element and lower roll shaft with due care
into eccentric cartridge.
Fig. 29
f. Insert cross-bar in assembly table and pass cross-bar through cross-hole provided in roll
shaft extension. On the other hand, the cross-bar keeps the roll shaft somewhat below the
final mounting position so as to allow the drive-side eccentric cartridge to be easily
assembled and, on the other hand, it blocks any rotation of the shaft when tightening the
slotted nut.

Fig. 30
g. Take care of correct combination between eccentric cartridge and roll shaft.
h. Lower drive-side eccentric cartridge half over roll shaft. Apply a layer of clean oil to
bearing bushes before. Insert both cylindrical dowel pins, secure by means of retainer and
insert socket head cap screws.
Fig. 31
i. Insert inner Lamiflex disk in eccentric cartridge prior to starting with installation of thrust
bearing on corresponding roll shaft neck.
j. As you can see the Figure, the roll shaft is raised above the mounting position proper by
means of a spacer (arranged between toothing and eccentric cartridge).
Fig. 32

k. Preheat thrust bearing to 60-degree Celsius and force into position by means of bearing
punch. Follow the figure.
Fig. 33
l. Thereupon, position ring as well as self-locking nut and tighten by means of tightening
device provide for this purpose.
Fig. 34
m. Lift roll shaft through a short distance and remove spacer. The self-locking slotted nut can
be reused five times without the blocking effect heating lost.
n. Thereupon, check radial clearance of drive-side plain bearing according to below figure
and write down on Record Sheet. Repeat same check in a plane offset through 90-degree
angle. Thereafter, insert retaining ring with outer Lamiflex disk in centering recess of
eccentric cartridge. Attach Lamiflex disk on retaining ring by means of a coat of consistent
grease.

Fig. 35
o. Insert self-locking screws and tighten as follows with the help of torque wrench.
Fig. 36
p. Tighten all self-locking screws M10x35 uniformly to a torque ranging from 23 to 25.3 Nm.
q. Thereupon, increase tightening torque of each self-locking screw to a torque ranging from
46 through 50.6 Nm.
r. After the afore mentioned operations are completed, the thrust bearing is seated both on
the roll shaft and in the eccentric cartridge in a virtually end-play-free manner. Due to this
end-play-free installation and taking into account the small end play in the bearing itself,
the wire rod tolerance obtained meet with every exciting demand. Apart from this, there is

no wear between the eccentric cartridge contact shoulder and the Lamiflex disks.
READING OF ALL PLAYS AND THEIR IMPORTANCE
Measuring operations to be performed for checking Assembled Roll Housing's.
Position of roll housing for measuring purpose:
Fig. 37
a. Radial play: Radial play is a summation of allowed clearance between Shaft, Clevite
bearings and Eccentric cartridge, Front wall.
Fig. 38
b. Axial play: It is summation of play in the thrust bearing and locking bar clearance.

Fig. 39
c. Pass Line setting: To achieve the maximum and minimum position of the roll shaft for
smooth rolling.
Fig. 40
d. High Level setting: It is very important for ensuring the shafts in a single plane.
STANDARD DIMENSIONS FOR 6- & 8-INCHES SHAFTS
Table. 1

MEASURING INSTRUMENTS USED FOR READINGS AND PLAYS CHECKING
1. Micro-meter
Fig. 42
2. Inside Micrometer
Fig. 43
3. Dial Gauges
Fig. 44

4. Starret dial Indicator
Fig. 45
IMPORTANCE OF PLAYS AND READINGS
1. If all the rolls are not following the pass line the bar coming from the mill deviates.
2. Shear out of the bar takes place.
3. Two shafts high level should be same, otherwise groove of two rings are not matched
correctly. Due to this the coil formed as semi-circular shape.
IMPORTANCE AND CHARACTERISTICS OF LUBRICATING OIL
a. Lubricant is a substance that reduces friction, heat, and wear when introduced as a film
between solid surfaces.
b. The viscosity of oil should not change with rise in temperature.
c. It ensures the adherence to the bearings and spread over the surface.
d. The lubricant must have high strength to avoid metal contact and seizure under heavy
loads. i.e. High viscosity index.
e. The lubricant should not react with surfaces.
f. It should be environmentally friendly.
g. The oil should be act as cleaning agent.
h. Demulsibility.
i. Corrosion prevention.

Lubricating oil used in Finishing block is MV525 (MOBIL VACUOLINE)
The Mobil Vacuoline 525 Series of lubricants are high performance heavy duty circulating oils
designed for the demands of No-Twist Rod Mills, excellent choice for circulation systems
lubricating gears and bearings. Mobil Vacuoline 525 Series are designed to meet the critical
requirements of the Morgan Construction Company's high-speed No-Twist Rod Mills.
Mobil Vacuoline 525 Series gives excellent resistance to oxidation and thermal degradation, a
high level of protection against wear. They possess excellent demulsibility that permits water
and other contaminants to separate readily from the oil in the system reservoir.
Features:
1. Good protection against rust and corrosion through a balanced high-performance lubricant
formulation.
2. Outstanding anti-wear performance.
3. Excellent water separation characteristics.
4. High resistance to oxidation and thermal degradation.
Applications:
a. No-Twist Rod Mills.
b. Moderate duty spur, bevel, helical and herringbone gear units.
c. Hydraulic systems.
OIL LEVEL MONITORING TABLE
Y
/
M
JAN FE MA APR MAY JUN JUL AUG SEP OCT NOV DE TOTAL
2
0
1
7
158
mm
115
mm
165
mm
165
mm
189
mm
188
mm
150
mm
190
mm
181
mm
135
mm
175
mm
125
mm
1936
mm
26
bl
19
bl
27
bl
27
bl
31
bl
31
bl
25
bl
31
bl
30
bl
22
bl
29
bl
20
bl
318
bl

2
0
1
8
129
mm
150
mm
150
mm
180
mm
247
mm
200
mm
125
mm
140
mm
115
mm
176
mm
140
mm
130
mm
1882
mm
21
bl
25
bl
25
bl
30
bl
41
bl
33
bl
20
bl
23
bl
19
bl
29
bl
23
bl
21
bl
310
bl
2
0
1
9
110
mm
130
mm
126
mm
100
mm
100
mm
18
bl
21
bl
21
bl
16
bl
16
bl
*bl=barrel, mm= millimeter
Table. 2
PROBLEM DESCRIPTION
From the above data Oil level Monitoring table, we have observed that there was more oil
consumption in Finishing Mill. Prevention of oil leaks is great importance because that may
lead to major oil consumption. As we observed from the above data in the year 2017 oil
consumption was about 322 barrels and 310 barrels in 2018.
Consumption of Lubrication oil is the major task because that need constant monitoring and
top-ups to maintain the ideal level of lubricant to operate properly. We investigate further
leakages, and we realize that leakage can be a significant problem on many levels. Oil
consumption is a major motivator for reducing external oil leakage.
So, what can be done about leakage that is costing all of this capital? The key is to repair
whatever is leaking and replace old mechanical connectors with new, more efficient fittings.
The problem is often locating the source of the leaks. At any given moment, leakage could be
developing from seals, fittings and covers.
Therefore, it should be assumed that there will always be some amount of leakage at any given
point in time, and that steps need to be followed to identify and correct the problem.
IDENTIFY THE SOURCE:

The first priority is to identify the leaks. This involves discovering which systems are leaking
and precisely where the leaks are coming from. A formal investigation and interview of the
maintenance teams in each area is the best way to identify the obvious and most serious leaks.
A system for identifying and recording the location of each leak must be made available to
maintenance and operations personnel. Leak detection tags should be provided so that leaks
can be marked and cataloged as they are identified in the plant. This strategy will cover a large
portion of the obvious or noticeable leaks.
INSPECT AND QUANTIFY:
As leaks are identified and recorded in a database, those responsible for managing leak
detection are required to inspect the leak to gain further information as to why the leak exists.
The leak should be evaluated for causes and possible redesign for prevention.
It is important to use the information gathered about leakage in the plant as a bench-marking
metric. The easiest way to understand the surface cost of leaks is to quantify the amount of oil
at each leak. For both small and large leaks, use a flask, jar or bottle and capture the leak for a
timed interval and record the amount. Use this information to extrapolate the volume of
leakage over the course of a day, week, month and year. Compare this to the cost of the
lubricant per gallon and determine a dollar value for each system. Compare this data to the
fluid consumption costs on a daily, weekly, monthly and annualized basis.
AVAILABLE INFORMATION:
A copy of each tag that is placed on plant equipment must be returned to the planning group.
The tag's information should include the volume of the leak on a per-minute basis, machine
name, the component and the location. The perceived cause of the leak is also essential for
continuous improvement. This information must get entered into a database for planning,
tracking, bench-marking and metrics.
PLAN:
Based on selected criteria, each recorded leak should be prioritized for repair based on the
volume of the leak, ease or difficulty of repair, system criticality and environmental
considerations. At this stage it is also important to consider alternative designs that can be
incorporated into the repair of the leak to prevent it from recurring.
REPAIR:
A planned and consistent approach to leakage repair is necessary to ensure leaks are identified,
quantified, recorded, planned and ultimately repaired. Repairs should include appropriate

advancements to help reduce the possibility of a recurring leak.
OIL TANK MONITERING AND INSPECTION OF ALL LEAKAGE POINTS
INTERMEDIATE BLOCK (IB):
1. stand 14 and 15 seals
2. module O-rings
3. oil pipe lines.
FINISHING BLOCK (FB):
4. Stand 16-25 Twin-lip seal
5. Module O-rings
6. line shaft
7. profile rings
8. Drain pipe
9. split covers
10. 3 High speed increasers
11. BGH Inspection doors
12. Pinch Roll seals
13. Pipe lines
14. water traps
15. laying head
After thorough inspection maintenance practices, the above-mentioned leakage points were
controlled and leakages from stand 14-25 modules are invisible.
PROBABLE SOURCES OF OIL LEAKAGE AT ROLL HOUSING
1) Twin-lip seal leakage
2) Module O-ring leakage

3) Flinger O-ring leakage
Afore mentioned all due to
a. Twin-lip seal leakage:
Lip damage
Seal cut
Seal ring broken
Improper mounting of seal
Teflon coating of flinger damage
Lip seizure
b. Module O-ring leakage:
O-ring cut
O-ring not properly fixed
Under size O-ring
c. Flinger O-ring leakage:
Flinger O-ring damage
Shaft worn out
This is due to relative motion between shaft and flinger.
Flinger worn out
This is due to under size of flinger and Contaminated lube oil.
Improper mounting
Under
 size flinger mounting

OIL LEAKAGE AT OUTER FLINGER IN MODULE: When we remove the outer Flinger, we can
able to see the oil leakage in module.
Fig. 46
Shaft worn out:
Fig. 47

Flinger worn out:
Fig. 48
Twin-lip Seal shear out:
Fig. 49

MOST PROBABLE ROOT CAUSE:
Twin-lip damage and Flinger worn out.
REASONS FOR ROOT CAUSE:
1. Chromium oxide coating of Flinger damage.
2. Relative motion of shaft and flinger.
3. Relative motion of flingers.
4. Contamination of Lube oil.
5. Improper ring mounting.
6. Taper wear out of shaft.
7. Taper wear out of Sleeve.
8. Mounting device problem.
9. Worn out Flinger seating area on shaft.
10. Worn out Seal plate at seal sitting area.
SOLUTION:
Solution to be given for EACH ROOT CAUSE:
ROOT CAUSE 1: Damage of Chromium oxide coating of Flinger damage
What is chromium oxide coating?
Chromium oxide coatings, or black oxide coatings, are a type of industrial coating that are applied using
lame spray or plasma electric arc coating processes. These types of coatings are highly effective as seal
surfaces, as well as improving abrasion and wear resistance. Chrome oxide coatings also have excellent
self-mating and anti-galling properties. This material is recommended for resistance to wear by
abrasive grains, hard surfaces, particle erosion and cavitation, all at temperatures below 540 C (1,000
F).
Chromium Oxide Coating Features:
Chrome oxide (Cr2O3) is an inorganic compound of chromium and oxygen. It is one of the principal
oxides of chromium and occurs naturally as the rare mineral eskolaite. Chromium oxide coatings
(Cr203 coatings) impart many of the material’s favourable characteristics to coated substrates,
including:
 Excellent Wear

 Excellent Abrasion Resistance
 High Chemical Resistance
 Anti-Reflective
 Chromium Oxide Coating Processes
If you are looking for plasma spray coatings that provide excellent self-mating, anti-galling and
corrosion resistant properties, plasma sprayed chromium oxide coatings are the perfect choice. Parts
that are affected by wear problems caused by cavitation, particle erosion, hard surfaces and abrasive
grains are excellent candidates for this material. Our chrome oxide coatings are custom-tailored to your
application’s specific requirements using our custom coating processes, which include:
Plasma Electric Arc
 Powder Feedstock
 Powder Combustion Thermal Spray
 Ceramic-Based Feedstock
ASB provides pre-machining and post finishing to OE dimensions for our chrome oxide coatings,
using diamond grinding wheels and diamond belts. Diamond grinding achieves smooth, polished
surfaces on Cr2O3, with a low coefficient of friction.
In addition, specialty chemistries, including fused and crushed mixtures or cladded oxide with titanium
dioxide additives, are also available to meet unique needs.
Chromium Oxide Cr203 Coating Applications:
Due to its colour chrome oxide is often referred to as a green or black oxide coating. Chrome oxide
coatings are useful in a wide range of additional industrial applications, including:
 Sealing surfaces on food processing equipment
 Enhancing different types of seals
 Improving abrasion and wear resistance
 Bearing protection from long wearing surfaces
Additionally, chrome oxide coatings are commonly applied to pump components, rotating equipment,
and other parts and components to improve wear resistance and chemical resistance.
What is the purpose?
 It provides fine surface finishing
 It reduces the friction between flingers surface and lip of twin lip seal so temperature on
the flinger surface reduces.
 Because of coating the lip of the twin lip seal will not worn out/shear out easily.
Why it is getting damage?

 Coating damage due to Ingress of cooling water into flinger, this leads to contamination
of Lube oil.
 Flinger worn out, this causes to irregular, non-concentric rotation of the flinger.
 Improper mounting of flinger.
How to avoid it?
 Proper mounting of flinger and seal plate along with twin lip seal.
ROOT CAUSE 2: Relative motion of shaft and flinger
Relative motion: Is the calculation of the motion of an object with regard to some other moving
object.
How it happens?
 Flinger worn out and shaft worn out due to O-ring damage.
 Improper mounting of flinger.
 Flinger sitting area damaged.
 Improper mounting of ring that leads to relative displacement between two flingers.
How it effects the seal and flinger?
 Seal lip seizure, and shear out.
 Flinger worn out.
 Flinger coating damage.
 Flinger O-ring damage.
How to avoid it?
 Proper mounting of O-ring and flingers.
ROOT CAUSE 3: Relative motion between two flingers
How it happens?
 Improper mounting of outside flinger or ring.
 Improper mounting of seal plate.
How it affects seal or flinger?
 Flinger inside edge damage, this leads to edge of outside flinger worn out and lip of seal
damaged.

How to avoid it?
 Proper mounting of Seal plate.
 Proper mounting of two flingers, Flingers should be mounted in concentrically.
 Improper mounting of Ring.
 Two inside edges of Flinger should be in contact.
ROOT CAUSE 4: Contamination of Lube Oil
What is the purpose of lube oil?
 To maintain oil film between plain bearing and shaft.
 Reduction of friction.
 To increase load capacity.
How it is getting contaminated?
 Ingress of cooling water into lube oil.
 Outside Flinger and Twin-lip seal damage.
How to avoid it?
 Seal plate should be fixed tight and properly.
 Apply sealant properly to the seal plat which acts as gaskets or washers.
 Proper mounting of Seal plate, Twin-lip seal, Flingers, Ring.
 Lip of Twin-lip seal should be contact on the surface of outside flinger.
ROOT CAUSE 5: Improper Ring Mounting
How it affects the Seal and Flinger?
 Out Flinger damage, it leads to relative motion between flinger.
How to avoid it?
 Use proper Ring mounting device.
ROOT CAUSE 6: Taper worn out of Shaft and Taper wear out of Sleeve
How it happens?
 Mounting device problem.
 Improper Sleeve mounting.

 Load applied shaft on the sleeve.
How to avoid it?
 While mounting and removing the sleeve handle carefully and properly.
 Locking key of ring insert properly.
ROOT CAUSE 7: Mounting device problem
It Causes: Sleeve wear out
Shaft wear out
ROOT CAUSE 8: Worn out Flinger sitting area on Shaft
Why it happens?
 Relative motion between shaft and Flinger.
 Improper mounting of Flinger.
 O-Ring damage.
How to avoid it?
 Mount Flingers, Seal plate, O-ring properly.
ROOT CAUSE 9: Worn out Seal plate at Seal Sitting area
Why it happens?
 Relative motion between Twin-lip seal and Flingers.
 Improper mounting of Twin-lip seal ring.
How to avoid it?
 Proper mounting of Seal plate, Seal ring.
PRECAUTIONS:
 During assembly of roll housing, clean the sub-assemblies properly.
 Ensure that lubricant oil should not be contaminated that leads to Flinger, Shaft worn
out and Twin-lip seal seizure.
 Mounting the Flinger and Twin-lip Seal Properly, Concentrically and Parallel.
 Apply Sealant (HYLOMAR) Which contains dichloromethane, it acts as Washer and

Gasket with very thin film.
 Ensure surfaces are clean and dry before applying the sealant. Apply a thin film
uniformly to all surfaces. Allow solvent to evaporate, assemble the joint, bolt down,
re-tighten after a few minutes.
 Cross check the readings and plays of the Roll housing before installing into the
Finishing Mill.
 O-Ring should be mount properly and use as per required size.
 Ensure that bolts should be fixed tight to the seal plate.
 Visit and check the Twin-lip seal and Flingers frequently, whether Lip of the Twin-lip
seal worn out or seizure and Flinger worn out.
 If lip of the Twin-lip seal worn out or seizure or Flinger worn out, recommend for the
New Flingers and Twin-lip Seal.
 Check the sleeve of ring at Ring grinding shop (RGS) with the help of trail shafts of
6-inch and 8-inch before mounting sleeve along with ring to the Shaft in finishing mill.
CONCLUSION:
This paper presents the project on Study and Analysis for reduction of oil consumption in
Finishing Mill, the rationale behind it, and its main activities which aim to reflect the
operational changes with the result of analysis of the leaks.
Our Thorough study and analysis were carried out to control leakages from this stand 14-25
modules in Finishing Mill.

SCHOOL OF MECHANICAL SCIENCES | IIT BHUBANESWAR 57

Visakhapatnam steel plant

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