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NATIONAL INSTITUTE OF TECHNOLOGY
JAMSHEDPUR
TRAININGREPORT
ROLLING MILLS
TRAINING ORGANISATION
-MECON LIMITED, RANCHI
(D...
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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 ...
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ACKNOWLEDGEMENTS
I WOULD LIKE TO SINCERELY THANK ALL THE OFFICIALS OF THE ROLLING
MILLS SECTION OF MECON LIMITED (A GOVE...
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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 R...
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THE TRAINING ORGANISATION
MECON LIMITED, FORMERLY KNOWN AS (METALLURGICAL & ENGINEERING
CONSULTANTS (INDIA) LIMITED) IS ...
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COLD ROLLING MILLS
PROCESS BY WHICH HOTROLLED STRIP ORSTOCK IS
INTRODUCED BETWEENROLLERS AND THEN SQUEEZED OR COMPRESSED...
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COLD ROLLING MILLS AREBASICALLYOF TWO TYPES
INCOLD ROLLING WEATTAINA REDUCTIONOF ABOUT30%-35% PERSTAND
AND AN OVERALL RE...
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COLD ROLLING:
AS DESCRIBED EARLIERITCANBE OF TWO TYPES, EITHERREVRSIBLEOR
TANDEM, DEPENDING UPONTHEREQUIREMENT. THE PAY ...
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HYDRAULICFORCEIS APPLIED ONTHEBACK UP ROLL WHICH PROVIDES
NECESSARY PRESSURETO ROLL THE WORK PIECE. THE FORCEGETS
TRANSF...
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THE VARIOUS ROLL TYPES ARE PICTORIALLYDEPICTED AS FOLLOWS:
SIX HI MILL FOUR HI MILL PAIR CROSS MILL
COMPARISON OF REVER...
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ANNEALING
WHY ANNEALING IS DONE?
o STEEL COILS ARE HARD AND BRITTLE AFTER COLD
ROLLING.
o HAS ELONGATED GRAIN STRUCTURE...
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3. Grain Growth
Increase in average size of crystals/grains on further annealing
subsequent to the completion of recrys...
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SKIN PASSING
WHY IS SKIN PASSING DONE?
 TO ACHIEVE THE OPTIMUM MECHANICAL PROPERTIES
o TO PREVENT OCCURRENCE OF STRETC...
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HYDRAULICS
THE ROLLING MILLS SECTION IN THE STEEL PLANT IS BY FAR THE
MOST TECHNOLOGICALLY ADVANCED SECTION BECAUSE AS ...
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PUMPS:
PUMPS ARE PRACTICALLY OF MANY TYPES BUT AS EXPLAINED TO ME;
HERE THEY ARE BROADLY CLASSIFIED AS POSITIVE DISPLAC...
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CONCLUSION
THE PROJECT REPORT CONSTITUTES ALL THE BASIC KNOWLEDGE AS
RECEIVED DURING THE 2 WEEKS IN ROLLING MILLS SECTI...
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NATIONAL INSTITUTE OF TECHNOLOGY1

Published on: Mar 3, 2016
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Transcripts - NATIONAL INSTITUTE OF TECHNOLOGY1

  • 1. 1 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
  • 2. 2 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.
  • 3. 3 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:
  • 4. 4 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
  • 5. 5 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.
  • 6. 6 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.
  • 7. 7 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
  • 8. 8 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.
  • 9. 9 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.
  • 10. 10 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
  • 11. 11 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.
  • 12. 12 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.
  • 13. 13 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.
  • 14. 14 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.
  • 15. 15 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.
  • 16. 16 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.

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