HOT STRIP MILLS Mechanical Equipment - SMS · PDF fileSMS DEMAG Hot Strip Mills 2 SMS Demag is the worldwide leading supplier of plant and equipment for the iron and steel industry

HOT STRIP MILLSHOT STRIP MILLSMechanical Equipment

METALLURGICAL PLANT and ROLLING MILL TECHNOLOGY

Hot Rolling Mills

SMS metallurgy

Hot Strip MillsSMS DEMAG

2

SMS Demag is the worldwide leading supplier of plantand equipment for the iron and steel industry. Ourspectrum comprises both the supply of complete newplants and the modernization of existing facilities.

Many years of experience and close cooperation withour customers in all continents are the cornerstonesof our success.

Working teams of experienced engineers from thefields of

designprocess engineeringR&Delectrical and automation systemsmanufacture

continually enhance our products to increase theiroperational dependability and maintenance ease. Inour workshops we manufacture, assemble and testall key components before they are shipped to thesite.

In addition, we offer our customers erection andcommissioning services including practice-orientedtraining of operating staff, qualified After Sales Ser-vice as well as know-how transfer.

Our customers value our integrated solutions andeconomical equipment as the basis for their success.

SOLUTIONSIntegrated, economicalSOLUTIONS

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CONTENTS

2 3 Introduction, Contents

4 5 Slab sizing press

6 7 Hydraulic adjusting systems

8 9 Mandrel-less coilbox

10 11 Drum-type shear

12 13 Crank-type shear

14 15 Descalers

16 17 Concepts for media distribution

18 19 Interstand equipment

20 21 Loopers

22 23 CVC PLUS technology

24 25 Laminar cooling system, edge masking

26 27 Compact cooling systems

28 29 Hot strip coilers

30 31 Polishing equipment


4

A slab sizing press in the roughing mill area offersdecisive advantages for more flexibility in hot strip pro-duction today and in the future. Width reductions of upto 350 mm in one pass enable the number of differentcasting sizes in the spectrum of the continuous casterto be reduced to just a few standard widths. Slabswhose widths considerably exceed the required fin-ished-strip widths boost the throughput of the continu-ous casting facility. A special Short-Stroke operatingmode at the slab head and tail results in less croppinglosses and higher yield. Robust construction and oper-ational reliability are the key characteristics of the con-tinually enhanced design. Compactness and smallmoving masses during the sizing process ensure justminor wear even after many years of operation.

MAIN DATA

Sizing force 22,000 kNWidth reduction up to 350 mmDrive power 4,400 kWFeed rate up to 300 mm/sSlab thickness up to 280 mmSlab width 650 to 2,300 mmSlab length 4 to 12 mSlab temperature 1,250 °C

The essential technological advantage of the slab sizing press over a conventional edger – besides the large width reduction – is the distinctly betterthrough-forming of the slab right to its center. Theslab sizing press produces flatter “dogbones” leadingto reduced respreading and greater sizing efficiency.

The slab sizing press is ideally suited for integrationinto existing facilities. Thanks to our many years ofexperience, the press equipment can be installedduring short shutdowns and precommissioned whileproduction is underway.

FEATURES

Simple design and robust constructionClosed frame to accommodate the forces in thesizing pressPatented kinematicsTailor-made technology package“Stop-and-Go” modeSlab transport by means of position-controlledpinch rollsHydraulic balancing

SLAB SIZING PRESSSLAB SIZING PRESS

Comparison of sizingand edging processes.

Sizing pass

Flat pass

Flat pass

Edging pass

Minimalbulbous edges

Majorbulbous edges

5

No relative movements between slab and toolLong tool service livesOptimized tool contourEasy tool changesProven press driveEfficient tool cooling

ADVANTAGES

Large width reduction in one passFewer casting sizesHigher production of the continuous casterReduced slab storageCorrection of off-size slabsEasier direct rollingGreater production flexibilityBetter through-formingExtremely constant width over the slab lengthImproved width tolerance along the entire stripHigher specific coil weightShort-Stroke operating modeVariable slab width over its length, if demanded

OPTIONS

„Flying” modeTool changing device

RECENT REFERENCES

2005 Handan Iron & Steel, China

2005 Maanshan Iron & Steel, China

2005 Anshan Iron & Steel, China

2004 Shougang Iron & Steel, China

2000 Wuhan Iron & Steel (HSM No. 2), China

2000 Salzgitter Flachstahl, Germany

2000 Ilva (TNA2), Italy

1998 Ilva (TNA1), Italy

1994 Sollac Fos-sur-Mer (Arcelor), France

1989 ThyssenKrupp Steel (Beeckerwerth),

Germany

Slab sizing press(view on the exit side).


6

MAIN DATA

Slab thickness 125 to 280 mmStrip width 650 to 2,200 mmStrip thickness 1 to 25 mm

Vertical adjusting systems

Adjusting speed up to 60 mm/s per sideAdjusting force up to 8,000 kN

Horizontal adjusting systems

Adjusting speed up to 12 mm/sAdjusting force approx. 50,000 kN

FEATURES

Robust designReliable and proven cylinder sealingDigital position measurementRedundant position and force measurement(in case of horizontal adjustments)

Four-high reversing roughing stand with edger.

ADJUSTING SYSTEMSHydraulic ADJUSTING SYSTEMS for horizontal and vertical stands

VERTICAL STANDS

The width of the strip from its head to its tail is con-trolled by means of hydraulic edger adjusting sys-tems. The quick dynamic response of these systemsenables the fast corrective movements at the materi-al head and tail as required to minimize croppinglosses and to control the width over the length of therolled stock.

Latest-generation edgers are fully hydraulic facilitieswithout any additional electro-mechanical adjustingsystems – a feature that reduces the amount ofmaintenance work considerably.

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Finishing stand.

RECENT REFERENCES

2005 Handan Iron & Steel, China E, R, F

2005 Bhushan Steel & Strips, India E, R, F

2005 Maanshan Iron & Steel, China E, R, F

2005 Handan Iron & Steel, China E, R, F

2005 Shougang Iron & Steel, China E, R, F

2004 Shanghai Meishan Corp., China E, R

2004 Taiyuan Iron & Steel, China E, R, F

2004 ThyssenKrupp Steel (Bruckhausen),

Germany R

2004 Sahaviriya Steel Industries, Thailand R

2002 Outokumpu Stainless, Finland R

2001 Wuhan Iron & Steel (HSM No. 1),

China R


China E, R, F

2000 Shanghai Meishan Corp., China F

1999 CST (Arcelor Group), Brazil F

1999 SSAB (Borlänge), Sweden E, R

1998 Benxi Iron & Steel, China E, R, F

1997 PT Krakatau Steel, Indonesia E

1996 Hadeed, Saudi Arabia F

1996 China Steel Corporation, Taiwan E, R, F

1996 EKO Stahl (Arcelor Group), Germany E, R, F

E = edger, R = roughing mill, F = finishing mill

HORIZONTAL STANDS

Strip thickness and strip travel control is accom-plished through hydraulic adjusting cylinders provid-ed in the roughing and finishing stands. In coactionwith hydraulic sideguides and the associatedautomation system, horizontal adjusting systems inthe roughing stand minimize camber and wedge,and thus ensure the rolling of a straight transfer bar.

The forward stands of a finishing mill are equippedwith hydraulic adjusting systems to safeguard stablestrip travel, while the close thickness tolerances ofthe finished strip are achieved mainly by means ofthe hydraulic adjusting cylinders of the rear finishingstands and suitable gage control.


8

The coilbox arranged between the roughing standand the finishing mill of a hot rolling mill forms coilsof transfer bars, thus serving as both material andheat accumulator. During uncoiling, the former trans-fer bar tail runs into the finishing mill as transfer barhead.

The coilbox is employed in new facilities and mod-ernized plants. Based on the experience gained frommore than half of all the coilboxes built worldwide –and in fact the very first mandrel-less coilboxes –SMS Demag has developed strategies allowing acoilbox to be installed into an existing facility within aminimum period of standstill.

MAIN DATA

Transfer bar width 650 to 2,200 mmTransfer bar thickness 20 to 40 mmTransfer bar temperature 900 to 1,100 °CCoil weight 4.5 to 40 tSpecific coil weight up to 25 kg/mmEntry speed up to 4.0 m/sCoiling speed up to 5.5 m/sUncoiling speed up to 2.5 m/s

FEATURES

Mandrel-less coil transferMaximum coiling speedsPosition-controlled bending rollsPosition- and pressure-controlled pinch roll leveler

OPTIONS

Adjustable heat insulating hoodCoil furnace

Economic and qualitative

ADVANTAGES

Higher specific coil weightsSmaller finished strip thicknessesBetter profile and thickness tolerancesFreely selectable distance between roughing milland finishing millReduced temperature loss due to shorter dwelltimes of the material on the roller tableTemperature equalization over the transfer barlengthLower rolling forces and less energy consumptiondue to higher temperature levelLess cropping losses due to longer transfer barsCoil storage in case of disturbances in the finishing millPossibility to use reheated coilsExtension of the product range

MANDREL-LESS COILBOXMANDREL-LESS COILBOX

Design of the mandrel-less coilbox.

9

RECENT REFERENCES

2005 Stelco Inc., Canada (revamp)

2005 Bhushan Steel & Strips, India


2004 Shanghai Meishan Corp., China

2004 Taiyuan Iron & Steel, China

1999 CST (Arcelor Group), Brazil

1998 Rautaruukki Oj, Finland

1997 Saldanha (Mittal Steel), South Africa

1997 Nucor (Trico), USA

1996 EKO Stahl (Arcelor Group), Germany

The patented mandrel-less transfer of the coil fromthe coiling to the uncoiling station prevents the innerwindings from cooling down, and our latest-genera-tion coilbox minimizes the temperature losses of thetransfer bar even further. Adjustable heat insulatinghoods for which a patent application has been filedreduce the heat radiation and hence the temperatureloss of the wound coil.

The optimized coilbox geometry enables higher coil-ing speeds, thereby shortening the dwell times ofthe transfer bar on the roller table.

Coilboxes with transfer mandrel can be revamped soas to incorporate all the benefits of a mandrel-lesscoilbox.

Mandrel-less coilbox in operation.


10

The drum-type shear installed between the roughingand finishing mills of a hot strip mill crops the trans-fer bar at its head and tail. In special applications, thedrum-type shear also serves to divide transfer barsand finished plates. Based on the experience gainedfrom more than 60 drum-type shears built so far,SMS Demag has set standards, and we offer ourcustomers a choice of various options to meet theirspecific requirements. An intelligent automation sys-tem featuring crop-length optimization reducesexpensive cropping losses.

In modernized facilities, the compact design of theSMS Demag drum-type shear permits the cuttingcapacity to be increased many times over whilemaintaining the given mounting space. Our long-standing experience and customized installationstrategies enable conversion jobs to be implementedwith but minor foundation modifications, short shut-downs and substantial precommissioning, also whileproduction continues.

MAIN DATA

Transfer bar width 650 to 2,200 mmTransfer bar thickness up to 60 (80) mmTransfer bar temperature 800 to 1,100 °CShear force 6,000 to 35,000 kNMotor power 500 to 3,000 kWSpeed 0.4 to 3.5 m/s

FEATURES

Compact, robust construction with closed frame,ideally suited also for modernizationsLow motor power required due to optimizeddesign and ratingPatented, high-speed knife change in the millPatented knife gap adjustmentPatented shear coupling

OPTIONS

Patented knife clamping device with hydraulicunclampingDifferent cutting contours possible for transfer bar head and tail cuts by using two knife pairs, arranged at angles of 90° or 180°Motor-operated knife-gap adjusting systemSwingable entry and exit rollersPractice-tried tools and auxiliaries for knife changingElectric drive, automation system and crop lengthoptimizationCustomized scrap removal systemQuick-changing shearCassette design for changing the drum set

DRUM-TYPE SHEARDRUM-TYPE SHEARin special applications

Design and componentsof the drum-type shear.

11

Drum-type shear with hydraulic knife clamping device in a hot strip mill.

RECENT REFERENCES

2005 Corus IJmuiden, Netherlands

2004 Outokumpu Avesta, Sweden


2003 Outokumpu Tornio, Finland

2003 Ternium, formerly Sidor (Techint Group), Venezuela

2002 PT Krakatau Steel, Indonesia



1998 SSAB, Sweden

1998 Salzgitter Flachstahl, Germany

1996 Hadeed, Saudi Arabia


1996 Carinox, Charleroi (Arcelor), Belgium

1994 Ipsco, USA

1994 Anshan Iron & Steel, China

Robust construction and operational dependability arethe key characteristics of the continually enhanceddesign. The use of two pairs of knives allows the cutting contours for the transfer bar head and tail tobe freely selected, thereby reducing the biting forcesand the number of rolling troubles in the finishingmill. The knife shape has been optimized so as toensure a perfect cut and long service lives.

Our patented hydraulic knife clamping system allowsinline knife changes and knife gap readjustmentswithin minimum time. There is no time-consumingslackening of nuts and screws, and the shear neednot be dismounted.

Both the change shear and the cassette-design shearfor changing the drum set come with optional equip-ment outfits allowing the shear or the drum set to bechanged within minimum time.


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CRANK-TYPE SHEARCRANK-TYPE SHEAR

The crank-type shear arranged between the roughingmill and the finishing mill serves to crop the transferbar at its head and tail. Higher material strengths andlarger transfer bar dimensions require ever-highercutting capacities. The SMS Demag crank-type shearis specifically designed for this field of application.

Great dependability in service, a robust design andeasy maintenance permit cost-efficient operation. Onaccount of the favorable cutting geometry, the crank-type shear particularly features great cutting reliabilityand long knife service lives.

Optimally rated drive motors with connectable fly-wheel masses guarantee a reliable cutting perfor-mance also when handling ultra-thick transfer bars at low speeds.

MAIN DATA

Transfer bar width 650 to 2,200 mmTransfer bar thickness up to 80 mmTransfer bar temperature 800 to 1,100 °CShear force 6,000 to 15,000 kNMotor power 500 to 3,000 kWSpeed 0.4 to 2.5 m/s

FEATURES

Compact, robust construction with closed frameLow motor power required due to optimizeddesign and ratingGreat cutting reliabilityNo shearing chipsLong knife service livesQuick knife change in the millClosed housing, low foundation loadsShear and drive gear from one sourcePatented knife clamping

OPTIONS

Knife clamping device with hydraulic unclampingKnife changing device for short changing timesMotor-operated knife-gap adjusting systemSwingable entry and exit roller tablesElectric drive, automation system and crop lengthoptimizationCustomized scrap removal systemChange shearDifferent cutting contours possible for the transfer bar head and tail by using two knife pairs

Entry of transfer bar head Head-end crop cut Exit of transfer bar tail Tail-end crop cut

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In the cutting area, the knives of the crank-typeshear move parallel to each other, thereby creating alarge overlap and ensuring very reliable cutting.Roof-shaped top knives reduce the required shearingforces markedly. When equipped with two differentknife pairs, different cutting contours can be select-ed for the transfer bar head and tail. The resultantbenefits include a reduction of the biting forces inthe finishing mill as well as fewer strip tail-endcrashes.

The knives are changed inline, optionally by using aknife changing device which will be placed on top ofthe scrap pit. Knife clamping can be implemented bymeans of spring clamping elements; there is notime-consuming slackening of screws and nuts.Thanks to the crop length optimization system, cost-ly cropping losses are minimized. Small total fly-wheel masses enable the speeds of transfer bar andshear to be adequately synchronized which in turnhelps to keep the length of crop pieces down to aminimum.

RECENT REFERENCES






Germany


1998 China Steel Corporation, Taiwan

1990 ThyssenKrupp Steel (Bochum),

Germany

1990 Sidmar (Arcelor Group), Belgium

Cutting principle of the crank-type shear with two knife pairs.

Crank-type shear in a hot strip mill.


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DESCALERSDESCALERS

Descalers are a must in hot strip mills for attaininggood surface quality. We have optimized ourdescalers so as to ensure maximal scale removal andhence perfect cleaning at minimum material cooling.

SMS Demag offers practice-tried solutions for anykind of application. Extra optional facilities allow thedescaler as well as the powerful high-pressure waterstation to be tailored to the specific requirements ofour customers.

Quick-changing devices and few moving componentsmean reduced maintenance times and costs.

MAIN DATA

Material width 650 to 2,200 mmMaterial thickness 15 to 280 mmSpeed 0.15 to 2.0 m/sWater pressure up to 400 barWater consumption 200 to 700 m3/h

Principle design of the descaler upstream of the finishing mill.

FEATURES

State-of-the-art nozzle technologyHighly effective application of HP waterClosed design to prevent water from escapingOptimized water flow inside the descaler for ser-vice water, side water and scaleSpraying headers of simple, maintenance-friendlydesign

OPTIONS

Several pairs of spraying headersConnectable and disconnectable spraying headersSeveral spraying widthsSpraying headers of quick-changing typeAutomatic level adjustment of spraying headersand water collecting troughsPinch roll unit also usable for strip retractionRemovable or hydraulically opening hood

Descaler upstream of the roughing mill.

15

Level adjustment of the top spraying headers andwater collecting troughs enables optimal adaptationto the thickness of the material just being handled.Due to the special nozzle arrangement, differentdegrees of cooling on the material upper side andunderside are minimized.

Undesired cooling of the material is reduced throughadequate design solutions. The time the water is lefton the material on completion of the cleaningprocess is minimized by the use of water collectingtroughs and squeegee rolls. Amply dimensionedwater ducts to the scale flume prevent water andscale turbulences. A more powerful entry pinch rollunit can also be employed to pull the strip back fromthe finishing mill.

A water connecting coupler of quick-changing typeenables the spraying headers to be replaced in mini-mum time without having to slacken any screwedconnections.

In modernized plants, state-of-the-art descalers allowto achieve a markedly better cleaning effect andhigher material temperatures. Advantages worthmentioning are the compact design and short con-version times.

RECENT REFERENCES






2004 PT Krakatau Steel, Indonesia

2003 Baoshan Iron & Steel, China




1999 SSAB (Borlänge), Sweden

1999 ThyssenKrupp Steel (Beeckerwerth),

Germany

1999 Ilva (TNA 1), Italy

1998 Benxi Iron & Steel, China

Descaler upstream of the finishing mill.


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Low-maintenance CONCEPTS for MEDIA DISTRIBUTIONLow-maintenance CONCEPTS for MEDIA DISTRIBUTION

We developed our novel, modular-design media pip-ing systems to ensure easier installation, greatermaintenance ease and maximal protection againstdamage during rolling.

Other than the previous technology which employedtwo hydraulic systems (280 bar for servo systemsand 180 bar for auxiliary functions), the novel pipingconcept features just one hydraulic system (280 bar).All controls (per stand) are accommodated in theform of compact control columns in the media plat-form.

FEATURES

Feeding of all hydraulic consumers on the standService pressure: approx. 280 barAll media consumers are connected to onehydraulic systemAll controls are located in the media platformEasy access and maintenance

The figure on the right is a look into the media plat-form showing the control columns and the commonterminal box. This compact design guarantees opti-mal maintenance of the hydraulic and mechanicalequipment. Also, the number of pipe connectionscould be reduced significantly, thereby minimizingthe risk of leaks.

The modules are interconnected by means of high-pressure hoses.

A look into the mainte-nance platform.

17

RECENT REFERENCES







2002 Outokumpu Stainless, Finland



Modular-design media piping onthe finishing stands.

Operator side of thefinishing stands.


18

INTERSTANDINTERSTAND equipment

EFFECTIVE and EASY TO SERVICE

Practice has shown that the interstand facilities arevitally important for the production of hot-rolled stripwith top surface quality.

Interstand equipment includes:Entry and exit guidesWork roll cooling systemAnti-peeling deviceRoll-gap lubrication systemInterstand cooling / descaling systems

Close interplay of all these facilities is a must toachieve an optimal result. Sideguides featuringhydraulic width adjustment ensure exact positioningwithin minimum time. The strip guide areas aredesigned so that all wearing parts can be replacedquickly. The cooling efficiency was improved thanks tooptimized selection and arrangement of the nozzles.

MAIN DATA

Strip width 650 to 2,200 mmStrip thickness 1 to 25 mmStrip temperature 800 to 1,100 °CCooling waterconsumption 300 to 1,000 m3/hPressure 10 bar at the nozzle

FEATURES

Optimal strip guidingOptimal roll coolingLower rolling forcesOptimized rolling-force distributionNo vibrationsAchievement of thinner finished strip gagesLonger rolling campaigns

The combination of our patented roll gap cooling, rollgap lubrication and improved exit-side cooling sys-tems reduces the roll temperature and the strip sur-face temperature. This results in a thinner oxidelayer on the roll surface with less work roll peelingfor consequence. Lubrication inside the roll gap mini-mizes friction, thereby enabling rolling force reduc-tions of 20 to 30%. In this way it is possible to re-distribute the rolling forces for optimizing the passschedule and achieving thinner final strip gages.Added to this is that chattering or vibrations in thestand are prevented which leads to longer roll ser-vice lives.

The kind of roll gap lubrication adopted depends onthe individual stands. Roll gap lubrication can beimplemented in three different operating modes asdepicted by the sketch above.

Operating modes of roll gap lubrication.

Lubrication over the full

strip length

Ro

llin

g f

orc

e F

3 {

kN

}R

ollin

g f

orc

e F

3 {

kN

}R

ollin

g f

orc

e F

3 {

kN

}

Lubrication of the strip body

(no lubrication on strip head and tail)

RGL active

RGL active

RGL active

Lubrication of strip body and tail

(no lubrication of strip head)

Strip without roll gap lubrication (reference level)

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RECENT REFERENCES









1999 Duferco La Louvière, Belgium

1 Work roll cooling, entry side · 2 Work roll cooling, exit side · 3 Work roll lubrication · 4 Strip surface cooling / Anti-peeling device · 5 Fume suppression · 6 Interstand cooling / Scale suppression · 7 Cooling of strip underside · 8 Strip sprayoff

The loopers arranged between the finishing stands ofa hot strip mill safeguard correct mass flow controland hence contribute to the stable rolling of finishedstrip down to a final thickness of <1 mm. The loop-ers are driven via hydraulic cylinders.

For the rolling of ultrathin strip, loopers featuring differential tension measurement (DTL) have been developed to detect strip tension differencesbetween the drive and operator sides which can be eliminated by swiveling the top roll set. Minor tension differences contribute to reliable unthreadingand help prevent tail-end crashes.

The function of the tensiometer looper (TML) is tomeasure the distribution of tensile stresses acrossthe width of the strip which represents an essentialprerequisite for automatic online flatness control. A tensiometer looper is preferably arranged betweenthe last two stands. We supply tensiometer and dif-ferential tension loopers complete with electronicevaluation unit for integration into the automationsystem.


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LOOPERSLOOPERS for hot-strip finishing millsand Steckel mills

MAIN DATA and FEATURES

Strip width 650 to 2,200 mmStrip thickness 1 to 25 mmStrip temperature 800 to 1,100 °CSpeed up to 20 m/s

Minimum moment of inertia due to optimized design by means of FEMPatented design for differential tension measurementPatented design for strip flatness measurement under tensionImproved flatness control

Tensiometer looper (TML).

Differential tension looper(DTL).

Standard looper.

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In Steckel mills, the so-called Steckel looper is locat-ed between the pinch roll unit and the coiling fur-nace to eliminate tension fluctuations produced bythe furnace drum. This enables higher rolling speedsso that the production of hot strip can be boosted byup to 20%.

RECENT REFERENCES


(standard looper, DTL)


(standard looper)




(standard looper)





2001 Shanghai Meishan Corporation, China

(standard looper)

2000 Outokumpu Avesta, Sweden

(Steckel looper)

2000 Wuhan Iron & Steel, (HSM No. 2), China


2000 ThyssenKrupp Steel (Bochum), Germany



(standard looper, TML)


(standard looper)

1996 SSAB (Borlänge), Sweden

(standard looper)

DTL = differential tension looperTML = tensiometer looper

Arrangement of Steckel looper roll.

Steckel looper roll.


22

CVC PLUSCVC PLUS -technology

CVC (classical, 3rd order) CVC (higher order)

Conventional CVC system CVC -system

Set

tin

g r

ang

e [μ

m]

1,200

800

400

0

Set

tin

g r

ang

e [μ

m]

1,200

800

400

0

183%

160%

127%

1,250 1,600 2,000

Strip width [mm]

1,250 1,600 2,000

100%

100%

100%

Strip width [mm]

During recent years, the production of hot strip hasseen considerably increasing demands made on theprofile, thickness, flatness and surface of the material.To meet this challenge, SMS Demag has enhanced theCVC technology which has already proved its worth inmore than 600 stands, the improvements relating toboth the mechanical equipment and the process mod-els. The new CVC PLUS technology comprises:

Work-roll shifting systemsCVC PLUS work-roll contour enabling a markedlywider setting rangeWork-roll bending systems, integrated in the shifting blocksCVC PLUS backup-roll contour to reduce roll loads(line loads)Process model for optimal utilization of theCVC PLUS technologyShape-optimized shifting strategies to prevent profile anomalies and extend the rolling campaigns

In new plants, all finishing stands come with our CVC PLUS shifting systems, and existing facilities can be retrofitted with CVC PLUS systems without anymajor modifications to their mechanical equipment.

CVC PLUS shifting and bending system ina finishing mill stand.

23

CVC PLUS shifting and bending system; shiftingstroke: ±150 mm.

RECENT REFERENCES








China

2000 SZFG (Salzgitter), Germany


More than 600 finishing stands were successfully equippedwith CVC technology.

MAIN DATA

Strip width 650 to 2,200 mmStrip thickness 1 to 25 mmSpeed up to 20 m/sBending force 0 to 1,500 kN per sideShifting stroke ±100... 150 (200) mm

FEATURES

Robust constructionSmall number of wearing parts due to fixed-blockdesign (up to 150 mm stroke)Reliable sealing against scaleLong service livesLow maintenanceConstantly small clearance between WR chocksand stand housings


24

LAMINAR COOLING SYSTEM, EDGE MASKING

Exit-end equipmentLAMINAR COOLING SYSTEM, EDGE MASKINGThe exit area located between the finishing mill andthe coiler of a hot strip mill is needed for materialtransport and material temperature setting, andhence for attaining the mechanical properties. Selec-tion of the roller spacings as a function of the stripthickness range safeguards reliable transport espe-cially of the strip head.

In coaction with a highly efficient cooling model, thelaminar cooling system arranged in this area ensuresthe desired coiling temperature as well as coolingaccording to preselected cooling strategies toachieve the desired mechanical properties of therolled stock.

The combination of laminar cooling system and edgemasking system prevents excessive cooling of thestrip edges, thereby minimizing stress differencesacross the strip width. As a result, cold strip flatnessis improved.

MAIN DATA

Strip width 650 to 2,200 mmStrip thickness 1 to 25 mmCoiling temperature 200 to 900 °CSpeed up to 20 m/sTotal water volume 4,000 to 14,000 m3/hCooling rate up to 80 K/sPressure 0.7 bar

Without edgemasking

With edgemasking

Strip width [mm]Te

mpe

ratu

re [°

C]Te

mpe

ratu

re [°

C]

Temperature profiles across the width upstreamof the coiler without and with edge masking.

Laminar cooling groupwith edge masking.

25

RECENT REFERENCES


2005 Bhushan Power & Steel, India









1998 Hoesch Hohenlimburg, Germany

1996 Hadeed, Saudi Arabia

1996 China Steel Corporation, Taiwan


1995 Aceralia Aviles (Arcelor Group), Spain

Laminar cooling system.

MAINTENANCE

The swingable arrangement (approx. 90°) of the topheaders of the laminar cooling system ensures readyaccess to the roller table so that roller changing bymeans of crane during maintenance jobs poses noproblem. Coming in the form of a complete quick-changing unit including motor, the rollers can bechanged within minimum time.

FEATURES

Compact designEasy maintenance thanks to swingable cooling headersQuick-changing device for roller changesSetting of the mechanical properties throughcomputer-model-aided cooling strategiesProduction of dual-phase and multi-phase steels


26

First and secondcooling steps

TF ~ 840 °C

Ferrite

T1 ~ 640 °C

Pearlite

Acceleratedcooling

Bainite

T2 ~ 200 °CMartensite

Length

Tem

pera

ture

COMPACT COOLING SYSTEMSCOMPACT COOLING SYSTEMS

The demands made on the cooling lines of hot stripmills on the one hand are determined significantly bythe dimensions of the rolled products and the coilingspeed. On the other hand, the development of innov-ative materials nowadays included in the productspectrum of hot strip mills has created furtherdemands.

In the case of high-strength, micro-alloyed steels, for instance, expensive alloying elements can besaved if the strip is cooled over a steep ramp rightdownstream of the finishing mill. Dual-phase andmulti-phase steels featuring high strength along withexcellent deformation behavior require the strip to be cooled in the cooling line, partly in several steps,from finish-rolling temperature (>850 °C) to less than200 to 300 °C.

Cooling strategy.

Elo

ngat

ion

afte

r fr

actu

re (%

)

Tensile strength (MPa)

Dual-phase steels

Complex-phase steels

Martensitic steels

TRIP steelsSingle-phase steels

Multi-phase steels

MAIN DATA

Strip width 650 to 2,200 mmStrip thickness 1 to 25 mmSpeed up to 20 m/s

Compact cooling systemWater volume 5,000 to 12,000 m3/hCooling rate up to 400 K/sPressure 3.5 bar

FEATURES

Compact designMaximal cooling ratesProduction of dual-phase and multi-phase steelsSaving of alloying elementsEasy maintenance due to swingable top side

New materials featuring high strengthand good deformation behavior.

27

RECENT REFERENCES


2001 Lianyuan Iron & Steel, China*

2001 Maanshan Iron & Steel, China*


Germany *

* CSP plants

To implement the high cooling rates, we have devel-oped compact cooling systems which apply largeamounts of water at higher pressure over a very shortdistance. Depending on the application in each case,these units are installed ahead of the conventionallaminar cooling line or just before the coiler. If required,the top side of the compact cooling system can beswung open to afford ready access to the roller table.

High-grade steels for carrying carbody parts areproduced with the aid of modern cooling lines.

Compact cooling system(open)


28

HOT STRIP COILERSHOT STRIP COILERS

A hydraulically adjustable entry guide provided at the terminal end of the runout roller table serves to center the strip before it enters the coiler station.The strip, running in at finish-rolling speed, is reliablyseized by the pinch roll unit and directed onto thecoiler mandrel. A holddown roll on the entry side of the pinch roll unit prevents the strip (especiallyheavy-gage strip) from bulging ahead of the pinchrolls.

With a view to the wide size range of hot-rolled strip(thicknesses from 1 to 25 mm; widths between 650and 2,200 mm) as well as the conditions and costsfor maintenance of the coiler station, the three-rollcoiler offers the largest number of practical benefits.Upon our customers’ requests, we have also suc-cessfully implemented four-roll coilers.

Our product spectrum also includes special thick-stripcoilers for coiling strip with large cross-section (e.g.2,100 mm x 25.4 mm) of high-strength steel grades(X70; X80) at low coiling temperatures (�470 °C).

MAIN DATA

Strip width 650 to 2,200 mmStrip thickness 1 to 25 mmCoiling temperature 200 to 900 °CSpeed up to 20 m/sCoil diameter 1,000 to 2,600 mm

FEATURES of PINCH ROLL UNIT

and SIDEGUIDE

Hydraulically operated sideguideExact adjustment of positions and forces as afunction of the strip width Exact hydraulic adjustment of the pinch roll gapAutomatic calibration of the pinch-roll-unit gapTakeover of the strip tension at the strip tail

FEATURES of COILER

Hydraulically operated wrapper rollsControlled spreading of the mandrel (hydraulic)Automatic calibration and exact hydraulic adjustmentof the gap between mandrel and wrapper rollsControlled limitation of the wrapper-roll forces as afunction of strip dimensions and materialStrip tension at the strip head built up after two tothree windings

In addition to their robust design and operationaldependability, our coilers particularly safeguard animpactfree coiling process and hence a good coilingresult. Reliable entry of the strip head is guaranteedthrough exact setting of the sideguides, the pinch-roll-unit gap, the wrapper roll gaps and the associat-ed drive speeds. By means of ìAutomatic Step Con-trolî, the wrapper rolls are operated so that in thecourse of coiling the strip head does not produce anymarks on the strip and the mechanical loads actingon the system, especially on the mandrel, are mini-mized. Full strip tension has built up already aftertwo to three windings and is kept constant over theentire length of the strip. This ensures tightly woundand straight-edged coils.

At the strip tail, the pinch roll unit takes over the striptension before the strip leaves the last finishingstand. Tension fluctuations are minimized in thisphase to avoid any offset windings at the strip tail.Prior to coil removal, the outer windings are prevent-

29

RECENT REFERENCES


2005 Bhushan Power & Steel, India


2005 Rautaruukki Steel, Finland

2005 NLMK Lipezk, Russia







2000 Stelco Lake Erie, Canada



1999 Sollac (Arcelor Group), France

1999 Ilva TNA 1, Italy

Over the last 15 years, SMS Demag has successfully commissioned more than 100 hydraulic hot-strip coilers.

ed from springing open by re-adjusting the wrapperrolls to the strip while the last one to two windingsare being coiled.

COILER MANDRELS

Also representative of the high technical standard ofthis mill area are the coiler mandrels: capable of with-standing extremely high mechanical and thermalloads, dependable in service, easy to maintain, longservice life. The position-controlled device for pre-expanding and further expanding of the mandrel con-tributes to rapid buildup of strip tension. Coiling com-pleted, the finished coils are removed from the coilerby means of a coil car.

Three-roll coiler with StepControl.

Schematic representation of“Automatic Step Control”.


30

In addition, the share of coils that have to be down-graded on account of surface defects is reduced. Forspecial applications, the polishing device can be sup-plied inclusive of an exhaust system.

MAIN DATA

Strip width 650 to 2,200 mmTemperature 200 to 900 °COscillation stroke variable

FEATURES

Patented procedure for roll polishingExtended service life between two regrindingoperationsLess downtimes for manual cleaning of the pinchrolls (50 to 60 h/y)

To cope with the increasingly stringent demandsmade in recent years on the surface quality of hotstrip, optical surface inspection systems have beeninstalled in a number of hot-strip finishing mills. How-ever, these systems can only detect defects, ratherthan eliminate or remove them. Our roll polisher is anefficient tool which helps prevent surface defects.

The production of stainless-steel hot strip in particu-lar involves the major risk of microparticles comingloose from the strip edges due to contact with theentry guides and getting stuck to the surfaces of the pinch rolls. These pickups cause surface defects.Therefore, the pinch rolls are cleaned at regular inter-vals. So far, this is mostly done by hand and inter-rupts the production process.

The polishing device installed in the entry section ofthe pinch roll unit upstream of the coiler ensures per-manent cleaning and hence prevents the formationof pickups. Thereby, the customers saves valuabletime otherwise needed to clean the pinch rolls, andthis time can be used for production.

POLISHING EQUIPMENTPOLISHING EQUIPMENTfor pinch rolls

2,5

2,0

1,5

1,0

0,5

025 33 41 49 5 13 21 28 37 45 1 9

Week

Do

wn

tim

e [%

]

Installationof polishingsystem

Polishing device on thepinch roll.

Times needed for coiler maintenance due tobottom pinch roll. Source: Arcelor Chertal.

31

RECENT REFERENCES



2005 Rautaruukki, Finland

2005 NLMK Lipezk, Russia


2003 Tata Iron & Steel, India




1995 Ipsco, USA0,8

0,6

0,4

0,2

044 52 8 16 24 32 40 48

Week

Ton

s [%

]

Installationof polishingsystem

Polishing device withexhaust system.

Downgraded coils due to pinch roll damage.Source: Corus, IJmuiden.

Polishing device.

MEETING your EXPECTATIONS

W4/

305

E15

00/0

7/06

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d in

Ger

man

ySMS DEMAG AG

Hot Flat Rolling Mills Division

Wiesenstrasse 3057271 Hilchenbach, Germany

Phone: +49 (0) 2733 29-1616Telefax: +49 (0) 2733 29-2832

E-mail: [email protected]: www.sms-demag.com

Documents

HOT STRIP MILLS Mechanical Equipment - SMS · PDF fileSMS DEMAG Hot Strip Mills 2 SMS Demag is the worldwide leading supplier of plant and equipment for the iron and steel industry