This document is a training report submitted by Nishant Singh after completing a one-month training at Mecon Limited in Ranchi, India. The report focuses on the cold rolling mills section of the company. It provides details on the different types of cold rolling mills, the cold rolling process, annealing and skin passing processes. It also includes a basic overview of hydraulics and hydraulic components used in rolling mills like directional control valves, pumps and accumulators. The conclusion expresses gratitude to the officials at Mecon Limited for their support and for helping the author gain fundamental knowledge on cold rolling and mill operations.

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NATIONAL INSTITUTE OF TECHNOLOGY
JAMSHEDPUR
TRAININGREPORT
ROLLING MILLS
TRAINING ORGANISATION
-MECON LIMITED, RANCHI
(DURATION-MAY 25th TO JUNE 24th 2015)
NISHANT SINGH
2013UGME076
SEMESTER-V
DEPARTMENT OF MECHANICAL ENGINEERING

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ABSTRACT
THIS REPORT IS BASED ON THE LEARNINGS ACHIEVED IN 2 WEEKS OF THE
ONEMONTH TRAINING SESSION IN MECON LTD. UNDER THE ROLLING MILLS
SECTION.
THIS REPORTPARTICULARLY FOCUSES ON THE COLD ROLING MILLS THAT ARE
ESSENTIALLY THE MOST IMPORTANT AND HIGHLY PRECISE MILLS OF THE
PLANT. MINOR DETAILS OF HYDRAULICS HAVE ALSO BEEN DEALT WITH
TOWARDS THE END.
THE INFORMATION PROVIDED IN THIS REPORT IN BASED ON THE
CUMULATIVEACCUMULATION OF ALL THE INFORMATION GAINED FROM THE
RESPECTIVE OFFICIALS AND READING THE PROVIDED DOCUMENTS.

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ACKNOWLEDGEMENTS
I WOULD LIKE TO SINCERELY THANK ALL THE OFFICIALS OF THE ROLLING
MILLS SECTION OF MECON LIMITED (A GOVERNMENT OF INDIA ENTERPRISE)
FOR THEIR GENEROUS AND AVID CONTRIBUTION TOWARDS MY
KNOWLEDGE IN THE SUBJECT WHICH WAS COMPLETELY NEW TO ME.
BECAUSE OF THEIR CONTRIBUTION, AT THE END OF THE TRAINING I HAVE
BEEN ABLE TO GAIN ATLEAST THE BASICS OF COLD ROLLING AND
HYDRAULICS, AND ALSO SOME KNOWLEDGE OF THE NATURE AND TYPE OF
WORK ACCOMPLISHED HERE IN MECON LIMITED.
OVERALL THIS LEARNING EXPERIENCE IN MECON LIMITED PROVIDED ME
WITH AN IDEA OF THE CHALLENGES FACED BY THE ENGINEERS IN
PROFESSIONAL LIFE AND AS A MATTER OF FACT TAUGHT ME THAT EVEN AN
IOTA OF NEGLIGENCE BY THE ENGINEERS CAN CAUSE GREAT HAZARDS
DURING UPCOMING PROCESSES AND SO THE JOB OF AN ENGINEER IS THAT
OF GREAT RESPONSIBILITIES.
REMARKS:

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CONTENTS
TOPIC PAGE NO.
1) THE TRAINING ORGANISATION 5
2) COLD ROLLING MILLS 6
3) TYPESOF COLD ROLLING MILLS
7
4) COLD ROLLING 8
5) PROCESSFLOW 9
6) REVERSING VS TANDM MILLS 10
7) ANNEALING 11-12
8) SKIN PASSING 13
9) HYDRAULICS 14-15
10)CONCLUSION 16

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THE TRAINING ORGANISATION
MECON LIMITED, FORMERLY KNOWN AS (METALLURGICAL & ENGINEERING
CONSULTANTS (INDIA) LIMITED) IS A PUBLIC SECTOR UNDERTAKING UNDER
THE MINISTRYOF STEEL OF THE GOVERNMENT OF INDIA.ITBEGANIN 1959 AS
THE CENTRAL ENGINEERING AND DESIGNING BUREAU (CEDB) OF THE
HINDUSTANSTEEL LIMITED (HSL), THE FIRST PUBLIC SECTOR STEEL COMPANY.
SUBSEQUENTLY, CEDB GREW AS METALLURGICAL AND ENGINEERING
CONSULTANT (MECON), A SUBSIDIARY OF THE STEEL AUTHORITY OF INDIA
LIMITED (SAIL) IN 1973. IT LATER BECAME AN AUTONOMOUS COMPANY
REPORTING TO THE MINISTRY OF STEEL IN 1978. 1 APRIL IS OBSERVED AS
FOUNDATION DAY IN MECON.
MECON LTD. IS A GOVERNMENTOF INDIA ENTERPRISEWHICH BASICALLYACTS
AS A HOUSEOF ENGINEERS WHO ASSIST VARIOUS STEEL MAKING COMPANIES
IN SETTING UP THEIR RESPECTIVE PLANTS AT PARTICULAR LOCATIONS FOR A
GIVEN REQUIRED PRODUCTION OF STEEL.
IT IS THE RESPONSIBILITY OF THE ENGINEERS OF MECON LTD. TO ENSURE
THAT ALL THE EQUIPMENTS, LAYOUTS AND OTHER DESIGN RELATED
INFORMATION SENT BY THE CONTRACTOR WHO HAS TAKEN UP THE WORK,
ARE COMPLETELY UP TO THE MARK AND ARE LIABLE ENOUGH TO BE
INSTALLED IN THE STEEL PLANT.
THE WORK ENVIRONMENTIS EXTREMELY SUITABLEWITH STATE-OF-THE-ART
FACILITIES FORALL THEEMPLOYEES AND THROUGHOUTTHE TRAINING
PERIOD ALL THEASSIGNED ENGINEERS WEREVERY CO-OPERATIVEAND
PROVIDED ALL THEREQUIRED INFORMATIONINAPPROPRIATEMANNER.

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COLD ROLLING MILLS
PROCESS BY WHICH HOTROLLED STRIP ORSTOCK IS
INTRODUCED BETWEENROLLERS AND THEN SQUEEZED OR COMPRESSED TO
THE DESIRED THICKNESS.
AMOUNTOF STRAININTRODUCED DETERMINES THEPROPERTIES OF THE
FINISHED PRODUCT
WHY IS COLD ROLLING DONE?
 GOOD FORMABILITY
 SUPERIORSURFACEFINISH
 REASONABLESTRENGTH
 CLOSEDIMENSIONAL TOLERANCE.
INTHIS TYPEOF ROLLING MILL THEROLLING PROCEDUREIS CARRIEDOUTAT
NORMAL TEMPERATURES AND NOT AT ELEVATED TEMPERATURES. ALSO
UNLIKEHOTROLLING, THECHANGEINTHE WIDTH IS ZERO.

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COLD ROLLING MILLS AREBASICALLYOF TWO TYPES
INCOLD ROLLING WEATTAINA REDUCTIONOF ABOUT30%-35% PERSTAND
AND AN OVERALL REDUCTIONOF ABOUT88%-90% IS ATTAINED INTHE
PROCESS.WHENTHEPRODUCTPASSES THROUGH THEPHASEOF HOT ROLLING
ITS TEMPERATURE IS VERY HIGH. SO AS ITGETS INCONTACT WITH THE
ATMOSPHERICAIR, THEOXYGEN REACTS WITH Fe AND FORMS SCALES (Fe2O3).
INORDERTO TREAT THE PRODUCTTHEREAFTER AN INTERMEDIATESTEP
KNOWNAS PICKLING IS NECESSARY.
PICKLING:
PICKLING BASICALLYIS A SCALEREMOVAL PROCESS INWHICH THEPRODUCTIS
PASSED THROUGHTHREE TANKS CONTAINING ACID (5 to 8 % acid) WHICH
DISSOLVES THESCALES AND THEN PASSED THROUGH A RINSING TANK WHICH
CONTAINS HOTWATERAND RINSES ACID STAINS(IFANY) ARE LEFTON THE
PRODUCT. THEN BRUSHING OF THEPRODUCTIS DONEINORDERTO FURTHER
CLEANITAND FINALLYA COATING OF anti rustOIL IS DONEONIT.
ARE SINGLE STAND 6 HI
COLD ROLLING MILLS
GENERALLY INSTALLED
WHEN BUDGET IS LESSAND
MATERIAL LOSS CAN BE
TOLERATED BY THE
MANUFACTURER.
REVERSIBLE
ARE 4 OR 5 STAND 6 HI
COLD ROLLING MILLS.
IF MATERIAL FINISH AND
EFFICIENCY OF THE MILL BE
CONSIDERED PRIMARILY
THEN TANDEMMILLS ARE
PREFERRED OVER
REVERSIBLE MILLS.
TANDEM

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COLD ROLLING:
AS DESCRIBED EARLIERITCANBE OF TWO TYPES, EITHERREVRSIBLEOR
TANDEM, DEPENDING UPONTHEREQUIREMENT. THE PAY OFF REEL AND THE
DELIVERYTENSIONREEL ARE COMMONINBOTH THE SETUPS.INREVERSIBLE
REEL THERE IS ONLYONE STAND AND SO THE MATERIAL IS PASSED THROUGH
THE SAME STAND AGAINAND AGAINUNTIL THEREQUIRED DIMENSIONS HAVE
BEEN ATTAINED AND FORTHIS PURPOSEENTRY TENSIONREELS ARE
PROVIDED.INTHISPROCESS THEREIS SIGNIFICANTLOSS OF MATERIALS ATTHE
ENDS.
WHEREAS INTANDEM MILLS 4 OR 5 STANDS ARE PROVIDED AND THE
MATERIAL PASSES THROUGH THESTANDS ONLY ONCEANDE FINISHED
PRODUCTIS RECEIVED ATTHE OTHER END. LOSSES INTHIS MILL ARE
NEGLIGIBLEAND ALSO BETTER FINISHED PRODUCTIS OBTAINED. TANDEM
MILLS REQUIREMOREAREA AND INSTALLATIONCHARGES AS COMPARED TO
THE REVERSIBLEMILLS.

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HYDRAULICFORCEIS APPLIED ONTHEBACK UP ROLL WHICH PROVIDES
NECESSARY PRESSURETO ROLL THE WORK PIECE. THE FORCEGETS
TRANSFERRED THROUGH THE INTERMEDIATEROLLS TO THE WORK ROLLS.
PROCESS FLOW
Pickling (to removeoxides and
scales)
Cold Rolling in reversing or tandem
mill to desired thickness
Annealing (batch or continuous)for
stress relieving
Skin passingto removeLuder lines,
develop mech prop,impartdesired
surface finish improveflatness
INSPECTION,FINISHING,DESPATCH.

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THE VARIOUS ROLL TYPES ARE PICTORIALLYDEPICTED AS FOLLOWS:
SIX HI MILL FOUR HI MILL PAIR CROSS MILL
COMPARISON OF REVERSING AND TANDEM MILLS
Criteria Reversing Mills Tandem Mills
Productivity Lower Higher
Efficiency Threading and tailling
off are required for
every coil.
Threading and tailling off
not required for every coil.
Increase in efficiency by 50
to 60%
Yield Lower yield - Off
gauge portion from
head and tail end
needs to be removed.
Higher yield - Off gauge
removal not required end
to end rolling achieved.
Use as combination mill
(reduction & temper
rolling)
Can be used. Can be used only for
reduction rolling

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ANNEALING
WHY ANNEALING IS DONE?
o STEEL COILS ARE HARD AND BRITTLE AFTER COLD
ROLLING.
o HAS ELONGATED GRAIN STRUCTURE.
o NOT SUITABLE FOR END USE.
STAGES OF ANNEALING
PROCESS OF RELIEVING INTERNAL STRESSES INDUCED DURING
COLD ROLLING TAKES PLACE IN THREE STAGES:
1. RECOVERY
PHYSICAL AND MECHANICAL PROPERTIES (HARDNESS, DUCTILITY,
ELECT PROP.)WHICH SUFFERED CHANGES AS A RESULT OF COLD
WORKING TEND TO RECOVER TO THEIR ORIGINAL VALUES.OCCURS
AT THE INITIAL PHASE OF ANNEALING AT LOWER TEMPERATURES.
2. RECRYSTALLIZATION
PROCESS OF NUCLEATION OF NEW STRAINFREE CRYSTALS
(GRAINS) WHICH REPLACES ALL DEFORMED CRYSTALS OF THE COLD
WORKED MATERIAL.TAKES PLACE AT A TEMPERATURE KNOWN AS
RECRYSTALLIZATION TEMPERATURE.

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3. Grain Growth
Increase in average size of crystals/grains on further annealing
subsequent to the completion of recrystallisation.
Grain size has direct effect on the mechanical properties. Hence it is
controlled to achieve optimum properties.
ANNEALING REQUIRES
Heating the cold rolled steel to the recrystallization temperature
in an inert atmosphere. Soaking at this temperature for sufficient
time for homogenization and necessary changes to occur. Cooling at
a predetermined rate
Process Variables:
Temperature, soaking, cooling rate depending on the desired
mechanical properties.

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SKIN PASSING
WHY IS SKIN PASSING DONE?
 TO ACHIEVE THE OPTIMUM MECHANICAL PROPERTIES
o TO PREVENT OCCURRENCE OF STRETCHER STRAINS IN
ANNEALED STEEL
o TO IMPART DESIRED SURFACE FINISH - “MATTE” ON THE
STRIP SURFACE
o TO IMPROVE STRIP SHAPE
WHAT ARE STRETCHER STRAINS?
Generated due to the yield point phenomenon exhibited by cold
rolled and annealed low carbon steel sheet/strip. Appear as discrete
bands on the strip surface.

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HYDRAULICS
THE ROLLING MILLS SECTION IN THE STEEL PLANT IS BY FAR THE
MOST TECHNOLOGICALLY ADVANCED SECTION BECAUSE AS FINISHED
PRODUCT IS DIRECTLY PROVIDED BY THE ROLLING MILLS, THE
TOLERANCE OF VARIOUS EQUIPMENTS INSTALLED IS VERY LESS AND
NEGLIGIBLE AS COMPARED TO EQUIPMENTS IN THE OTHER SECTIONS.
THEREFORE MECHANICALLY CONTROLLED SYSTEM WOULD NOT BE
AN IDEAL OPTION FOR OPERATING THE EQUIPMENTS AS
MECHANICALLY CONTROLLED EQUIPMENTS WOULD PROVIDE LESS
EFFICIENCY, WOULD REQUIRE FREQUENT AND EXPENSIVE
MAINTENANCE. THOUGH THE HYDRAULICALLY CONTROLLED SYSTEM
REQUIRES MAINTENANCE BUT THERE IS NO EFFECT ON THE
PRODUCTION DUE TO THAT DURING THE MAINTENANCE PERIOD.
HENCE NOWADAYS THE HYDRAULICALLY CONTROLLED SYSTEM IS
BECOMING MORE AND MORE POPULAR IN ALL THE SECTORS.
HERE, I LEARNED ONLY THE BASICS OF A HYDRAULIC CIRCUIT THAT IS
USED TO EQUIP A CYLINDER PISTON SYSTEM.
THE FEW COMPONENTS THAT I CAME ACROSS WERE AS FOLLOWS:
DIRECTION CONTROL VALVE:
THIS VALVE CAN BE DESIGNED IN VARIOUS TYPES DEPENDING UPON
THE REQUIREMENT. ITS BASIC NEED IS TO CHANGE THE FLOW
DIRECTION OF THE WORKING FLUID IN ORDER TO MAINTAIN
CONTINUITY IN THE WORKING OF THE SYSTEM AND TO ENSURE THAT
THE FLOW DIRECTION OF THE FLUID IS IN THE PATH AS REQUIRED BY
THE CIRCUIT.
CHECK VALVE:
ITS BASIC NEED IS TO PREVEN THE WORKING FLUID FROM FLOWING
BACKWARDSIN THE CIRCUIT TOWARDS THE PUMP.

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PUMPS:
PUMPS ARE PRACTICALLY OF MANY TYPES BUT AS EXPLAINED TO ME;
HERE THEY ARE BROADLY CLASSIFIED AS POSITIVE DISPLACEMENT
PUMP AND NON POSITIVE DISPLACEMENT PUMP.
IN A POSITIVE DISPLACEMENT PUMP THE SEALING BETWEEN THE
INNER VEIN, PLUNGER OR PISTON AND THE OUTER SHELL IS VERY
FIRM SO THAT THE INPUT FLUID IS EQUAL TO THE OUTPUT FLUID OF
THE PUMP AND IT SUFFERS NO LOSSES.
WHEREAS IN A NON POSITIVE DISPLACEMENT PUMP SUCH AS IN A
CENTRIFUGAL PUMP, THE PUMP SUFFERS FLUID LOSES BECAUSE OF
POOR SEALING. THIS TYPE OF PUMP IS CHEAPER AS COMPARED TO A
POSITIVE DISPLACEMENT PUMP.
BUT IN A HYDRAULIC CIRCUIT ONLY POSITIVE DISPLACEMENT PUMPS
ARE PREFERRED.
SUCTION COMPENSATOR:
A SUCTION COMPENSATOR BASICALLY ABSORBS THE VIBRATIONS
GENERATED BY THE PUMP OR WHICH EVER PORTION IT DEALS WITH
SO AS TO PREVENT ANY DAMAGE TO THE CIRCUIT.
ACCUMULATOR:
ITS USE IS TO ENSURE THAT THE CIRCUIT IS ALWAYSWORKING EVEN
IF THERE IS NO POWER SUPPLY FOR SOME TIME IN THE MOTORS.

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CONCLUSION
THE PROJECT REPORT CONSTITUTES ALL THE BASIC KNOWLEDGE AS
RECEIVED DURING THE 2 WEEKS IN ROLLING MILLS SECTION OF
MECON LIMITED, RANCHI. ALL POSSIBLE EFFORS HAVE BEEN MADE
TO PROVIDE LEGITIMATE INFORMATION IN THE REPORT BUT A
KIND CONSIDERATION IS EXPECTED FROM THE READERS IN CASE
ANY INEVITABLE ERROR MIGHT HAVE CREPT IN.
THE SUPPORT AND GUIDANCE OF ALL THE OFFICIALS DESPITE THEIR
OWN WORKLOAD THROUGHOUT THE COMPLETION OF THE
REPORT IS HIGHLY COMMENDABLE AND APPRECIATED FROM THE
STUDENT'S END.
THANK YOU.