Hot Rolled Steel Strip

Company ofThyssenKrupp

Steel Hoesch Hohenlimburg

TK

2

Hubbalkenofen Reversier-Vorstraße

Hohenlimburg hot-rolled narrow steel strip

Hohenlimburg narrow steelstrip is produced by hot-rollingfrom slabs and available inwidths up to 700 mm and inthicknesses from 1.5 to 16 mm.

Hohenlimburg narrow steelstrip is available with milledges, with cut edges slit frommultiple widths, or with trim-med edges.It can be supplied in coils weig-hing up to 20 kgs/mm stripwidth or in bars from 1 to 18 min length, pickled, non-pickled,or heat-treated.

Hohenlimburg narrow steelstrip represents the sum of ourmore than 100 years of expe-rience in steel production andprocessing. Our narrow-stripmill has been continuousmodernized over the years andis now completely process-automated. There is noquestion that it offers the bestprerequisites for achievingsuperior tolerances and tech-nological properties ongoing.

Hohenlimburg narrow steelstrip signifies:

• Extremely tight thicknesstolerances

• Optimum symmetric thick-ness in profile

• Superior surface quality• Uniform material properties• Application-specific micro-

structures • Optimum shaping proper-

ties including in higher-strength steels

• Customized batch sizes

Hohenlimburg narrow steelstrip will not only maintain itsqualitative superiority but willenhance it even further. Toachieve this ambitious goal, we are making considerableinvestments. Our plant andmachinery is state-of-the-artand guarantees the impressiveproduct advantages ourHohenlimburg narrow steelstrip is famous for.

Hohenlimburg narrow steelstrip is used in nearly all bran-ches of industry. As a result of our ongoingresearch and development ofour product quality, and basedon our long-standing experien-ce from listening to our custo-mer´s needs and requests, wecan now offer a solution to anyproblem our customers maycome up with.

You will find our technical appli-cation consultants able toassist you in your specificapplication.

Please contact us.

Walking beam furnaceThe walking beam furnaceoffers optimum prerequisitesfor

• Homogenous soaking ofthe rolling stock from allsides.

• High flexibility of the hea-ting process by elevenindependent temperaturecontrol zones.

• A process-controlledtime/temperature profileoptimally adapted to therespective material duringthe heating-up process.

Reversing roughing millThe high-capacity universalreversing mill equipped withhydraulic gauge and width con-trol system consists of a hori-zontal 2-high stand with a flan-ged-on edger in front and fullyautomatically rolls slabs of awide variety of sizes into inter-mediate strips.

This means:• Microstructures with

homogenous density areachieved by high reductionratios.

• Highly effective descalingassures optimum roughstrip surfaces.

• Computer-controlled rollingproduces geometricallyoptimized intermediatestrips.

Walking beam furnace

Reversing roughing mill

Wärmehauben Fertigstraße Kühlstrecke Haspelanlage

Narrow steel strip millTechnical description

Thermal tunnelThe thermal tunnel with itshighly effective heat insulationis configurated to assure that:

• The temperature is re-homogenized throughoutthe cross section profile(avoidance of edge cooling).

• The essential final rollingtemperature is maintainedat a constant level over theentire strip length even incoils with very high specificweights.

Finishing trainThe finishing train consisting of two 2-high and seven 4-highstands is equipped with a high-tech process automationsystem developed by ourselvesand offering the followingadvantages:

• Extremely narrow thicknesstolerances even at the striphead of the first coil follo-wing a size/quality change.

• Selective control of stripcamber and flatness byload distribution strategiesand roll bending.

• Maintaining the specificallyrequired final rolling tempe-ratures within narrow limits.This process is assisted byan integrated ”speed-upsystem“.

The process-automated edgersinstalled in front and behindthe 2-high stands are instru-mental in assuring extremelynarrow tolerances in thefinished strip width.

Cooling sectionThe laminar cooling sectionbased on specific cooling stra-tegies and advanced processautomation using neuronal net-works allows:

• Targeted setting of speci-fied microstructure condi-tions.

• Achievement of mechani-cal-technological propertieswith very tight tolerances.

Coiler groupThe computer-controlled coiler group with its baseconstruction and the possibility,to adapt the coiling parametersettings to the various materi-als, provides:

• Tight, straight-edged coilingand, thereby

• the right conditions for pro-cessing without mechanicaldamage.

An automatic strapping machineties up the coils in the coilingcellar directly behind the down-coiler (in longitudinal direction).

Thermal tunnel Finishing train Measuring house

Cooling section Downcoiler

4 Production equipment

View into the walking beam furnace

Thermal tunnel (open) Cooling section

Coiler below floor level

Reversing roughing stand

Finishing train

5

Surface conditions

Total view of the pickling line

Parsytec surface spray-pickling system

Total view of slitting line III

Heat treatments

Additional processing

TolerancesOur production is based on DIN EN 10048/DIN EN 10051for hot-rolled strip (dependingon the rolling width) and onDIN 59200 for wide flat steel.

Upon request, we can alsoproduce to other domestic orforeign standards. Processautomation allows thicknesstolerances similar to thoseapplicable for cold-rolled strip.The cut-to-length lines arecapable of maintaining verynarrow length tolerances forhot-rolled strip in bars andplate steel.

Surface conditions with wellpicklable homogenous surfacepickled (dry)pickled and oiled.

A wide range of microstructu-res can be produced directlyvia the rolling heat.Additional heat treatments:• Stress-relief annealing• Soft annealing• Spheroidizing on globular

cementite

• Chloric-acid pickling linesfor all cross sections andqualities produced (conti-nuous pickling line andpush-pull pickling line).

• Slitting lines (up to cutting-to-length line including 12 mm thickness).

6

Mild unalloyed steels (DINEN 10111:1998)

Designation Designation Special features

(according to (according to

DINEN 10111) DIN 1614, part 2)

DD14 StW 24 W *) Best cold-formability

DD13 StW 24 Very good cold-formability

DD12 StW 23 Good cold-formability

DD11 StW 22 Basic grade

Increased minimum yield point

— StW 24 H **) and special microstructur to achieve

high endurance values

*) Hoesch special quality **) Hoesch special quality (increased carbon content compared to StW 24)

Mild unalloyed steels and general structural steels

By special rolling processesand suitable temperature con-trol we can produce hot-rolledstrip for the production of RPcold strip surfaces.

General structural steels up toS 355 with good cold-formabili-ty (chamfering, roll profiling)can be produced by using avery low sulphur content andother measures during steelproduction.

In view of their good cold-for-mability, we recommend micro-alloyed fine grain structuralsteels for applications deman-ding high yield points and ten-sile strengths.

To replace the no longer produ-ceable rimming steels, we havedeveloped a vacuum-killeddeep-drawing quality for case-hardening. This steel containsonly small traces of aluminumand can (in most cases) becase-hardened like rimmingsteel.

For the deep drawing of shellsand similar structural compo-nents we supply steels withvery low earing characteristics.That applies for direct proces-sing as well as after a cold rol-ling process. The chemicalcomposition and the productionparameters are tailored to spe-cifications.

By suitable temperature controlwe can produce hot-rolled stripwith a carbon content of lessthan 0.20%, with a uniformfine microstructure suitable forfine blanking without prior heattreatment.

Mild unalloyed steels are deli-vered to ENDIN 1614, part 1,for cold rolling and to DINEN10111 for direct cold forming(direct processing of the hot-rolled strip). General structuralsteels are standardized toDIN EN 10025, but are alsoavailable as pre-material forother products, e.g. steel pipesfor long-distance pipelines, forflammable liquids and gases toDIN EN 10208.

Apart from standardized quali-ties, we are offering numerousspecial qualities optimal adap-ted to their intended final use.

In the case of mild unalloyedsteels for direct processing wehave developed special quali-ties in addition to gradesDD11, DD12, DD13 to DINEN10111. For instance, a verysoft quality (now DD14) withyield points otherwise onlyachieved by cold strip, and onequality with a somewhat highertensile strength but still excel-lent cold-formability.

7Examples of application

Control arm, 2.75mm thickSupport with outside fins,

4.0mm thick

Brake support plate,2.25mm thick

Brake piston,6.0mm thick

Gear part, monobloc design,6 .5mm thick

Shock absorber support,2.0mm thick

Trailing arm, 2 .5mm thick

Claw for alternator,10.5mm thick

8 Micro-alloyed low-perlitic fine-grain steels

These fine-grain steels are fullykilled micro-alloyed steels withlow carbon equivalents. Due totheir chemical composition andfine-grain microstructure achie-ved by thermo-mechanical tre-atment, these steels have highyield points and very goodcold-formability. An even hig-her degree of cold-formabilitycan be achieved by a very lowsulphur content or "sulphidecontrol", i.e. fixation of the sul-phur to avoid the formation ofundesirable manganese sulphi-des. The precisely controlledproduction on our hot strip millis realized by precise setting ofthe rolling temperatures andreduction rates as well as bycontrolled cooling rates andreel temperatures after rolling.

Our production program inclu-des N grades which are alsorolled under controlled condi-tions. Analysis and temperatu-re are selected to permit sub-sequent normalizing underspecified conditions. For further details, see ourspecial brochure.

Hot-rolled fine-grain structuralsteels are particularly suitablefor direct processing with highrequirements on cold-formabili-ty. This is much more advanta-geous than with conventionalstructural steels because of thechemical composition andmicrostructure. HSM steels(Hoesch special structuralsteels, micro-alloyed) can bebent with small radii and rolledinto profiles. They can also bedeep-drawn and stretch-for-med, with certain restrictions in the case of the harder quali-ties.

These fine-grain steels offerthe engineer good cold-forma-bility and high yield strengthsat the same time. With othersteels, similar properties canonly be achieved by heat treat-ment of the component. Thelow-carbon, manganese, andmicro-alloy contents create alow carbon equivalent and the-refore ensure good weldability.Only qualities with minimumyield points of 600 N/mm2 andabove, and the N grades canreach a carbon equivalentcomparable to structural steelof S 355 (DIN EN 10025).

Further details, in particularwith regard to chemical compo-sition and mechanical proper-ties, including several potentialapplications, are described inour special brochure.

Nomenclature

*) Acc. to the Stahl-Eisen-Liste, 1990 Edition

Hoesch designation Material No. Designation in Designation toStahl-Eisen-Werkstoff- DIN EN 10 149/2, blatt 092-90 1995

HSM 260 1.0970* (Q St E 260 TM*) –HSM 300 1.0972* (Q St E 300 TM*) S 315 MCHSM 340 1.0974 Q St E 340 TM –

– 1.0976 – S 355 MCHSM 380 1.0978 Q St E 380 TM –HSM 420 1.0980 Q St E 420 TM S 420 MCHSM 460 1.0982 Q St E 460 TM S 460 MCHSM 500 1.0984 Q St E 500 TM S 500 MCHSM 550 1.0986 Q St E 550 TM S 550 MCHSM 600 1.8969 (Q St E 600 TM*) S 600 MCHSM 650 1.8976 (Q St E 650 TM*) S 650 MCHSM 700 1.8974 (Q St E 690 TM*) S 700 MCHSM 760 Special Hoesch quality

9

Cold-rolled profile for railway wagons,HSM 700, 2.0mm thick

Car seat slide rails, 2.0mm thick

Ball pressure reservoir,3.5 – 6.5mm thick

Seat belt retractor cage,1.75 – 3.5mm thick

Steering column, various thickesses

Truck side members,4.0 – 12.0mm thick

Hot-rolles components for car jacks,2.0 – 4.0mm thick

Rear axle carrier, 6.0mm thick

Carrier plate, 8.2 mm thick

Car lock, various partsfrom hot strip

Gear component, 1st stage

Gear component, 2nd stage

Gear component, 3rd stage

Gear component, 4sth stage

Gear component, 5th stage 4.85mm thick

Examples of application

10 Case-hardening and heat-treatable steels

These are primarily steels accto DIN EN 10083 and DIN10084 but also nitriding steels(DIN EN 10085), steels forflame and induction hardening(DIN EN 10086), numerous toolsteels to DIN EN ISO 4957, andhot-rolled strip for heat-treata-

ble springs (DIN EN 10089) aswell as for cold-rolled strip steelfor springs (DIN EN 10 132-4).Furthermore, we supply variousspecial qualities, e.g. hot-rolledstrip for welded gas bottles(DIN EN 10 120) and for deepdrawn and/or stretch-reducedgas bottles, hot-rolled strip forcold-rolled tape rules, hot-rolledstrip for razorblade steel, etc.

The production of these steelsis optimally tailored to thecustomer´s intended use. Thisis valid for the chemical analy-sis, the hot-strip productionparameters, and any subse-quent heat treatment.

A fine, predominantly sorbiticmicrostructure has proven itsworth in the cold-rolling ofcase-hardening and heat-treatable steels. This permits

to cold-roll without prior heattreatment. For instance, qualityC75 steel can be cold-rolledwith a reduction of up to 60%,depending on the capabilitiesof the cold rolling mill. Steelswith a predominantly sorbiticmicrostructure offer advan-tages in hardening or heattreatment: shorter austeniza-tion times, lower hardeningtemperatures, more consistentproperties.

Cold strip (-LG) with lower yieldpoints and strength values mayrequire a less fine sorbiticmicrostructure in the hot strip.In-depth discussions swith thecustomer are recommended tooptimize the product for itsintended use, taking intoaccount the available produc-tion equipment.

The direct processing of hot-rolled strip requires a specialheat-treated condition. Thisapplies especially to fine blan-king. While a fine as-rolledmicrostructure is usually opti-mal for case hardening steelswith a low carbon content, anannealed microstructure ofspheroidal cementite is suitablefor fine blanking of hot-rolledstrip with higher carbon con-tents.

It is important to choose thecorrect chemical compositionfor deep drawing carbon steels.A very low sulphur content isespecially important, often alsoa low silicium content. Furtherprocessing by cold-rollingshould start with a fine sorbitichot-strip microstructure. If hotstrip is directly processed, theoptimal delivery condition willdepend on the production pro-cesses available at the custo-mer´s works. We would be ple-ased to advise you in thisrespect as well.

As a precaution against the riskof graphite precipitation and tooptimize heat treatment proper-ties, we recommend the lowestpossible aluminum content anda chromium content of approx.0.20%. Experience has shownthat this chromium content isnot detrimental to further pro-cessing. However, if an alumi-num-killed fine-grain steel isrequired, or if - in rare cases -the chromium content is notdesired, the processing para-meters may have to be setaccordingly.

Annealing shop

Soft annealed microstructure consistingof spheroidal cementite in ferrite,quality C60 (magnification x 500).

Sorbitic microstructure of a hot-rolledstrip, quality C60 (magnification x 500).

11Examples of application

Steel bottle, 5.5mm thick

Safety belt adjuster, 2.2mm thick

Cutter knife,8.0mm thick

Clutch discs, 5.0 – 8.5mm thick

Gear shift forks, 6.0mm thick

Clutch diaphragm spring, 3.5mm thick

Hole plate as turntable for expanding reel, 8.0mm thick

Clamping sleeve,5.0mm thick

12 Hot-rolled boron-alloyed Case-hardening and heat-treatable steels

We are continuously workingon the development of specialsteel grades some of whichhave already been described inthe previous chapters. Anotherexample are our boron-alloyedsteels (DIN EN 10083-3 andspecial steel grades, see tablebelow).

Hot-rolled boron-alloyed steelswith medium carbon contentsare particularly suited for appli-cations where moderately highstrengths and, therefore, stillquite good cold-formability inthe as-rolled condition arerequired, although high hard-ness values are neverthelessexpected after hardening.

These steels can be quenchedeither in water or in oil. Tempe-ring after hardening can gene-rally be omitted because of thevery high tenacity of the mate-rial. In special cases, tempe-ring at very low temperatures(180°C max) may be advisable.

Boron steels have proven theirworth especially in agriculturalmachinery, where they haveprimarily replaced silicium-

alloyed steels (38 Si 7m 55 Si7). One of their advantagesover Si steels is low sensitivityto decarburization during heattreatment.

A wide variety of other applica-tions rely on boron steelsbecause of the above advanta-ges for rational production pro-cesses.

Apart from boron-alloyed steelswhich are used instead of heat-treating steels, we can supply aboron-alloyed case-hardeningsteel (Hoesch brand HLB 8)which stands out by the highstrength and ductility values inits uncarborized core area.

For further information, pleasesee our brochure "Hot-rolledboron-alloyed case hardeningand heat-treatable steels".

Hoesch designation Steel grade Designation to Standard of qualityDIN EN 10027-1 *) DIN EN 10027-1 *) DIN EN 10083-3

HLB 8 8MnCrB3 1.7135 –HLB 17 17MnB3 1.5506 –HLB 22 22MnB5 1.5528 20MnB5 **)HLB 27 27MnCrB5-2 1.7182 27MnCrB5-2HLB 30 30MnB5 1.5531 30MnB5HLB 37 37MnB4 1.5524 38MnB5 **)HLB 42 40MnB4 1.5527 39MnCrB6-2 **)HLB 44 – – –

Fixing angle, 3.0mm thick

Fastening angle, 4.0mm thick

Chain link, 2.5mm thick

*) acc. to Stahl-Eisen-Liste**) Minor deviations for single elements. All grades according to DIN EN 10083-3

are available upon request.

Passenger car rear axle carrierthickness 2.75mm

13

Temperature control and documentation

14

Available sizes:

14

12

10

8

6

4

2

16

14

12

10

8

6

4

2

16

14

12

10

8

6

4

2

16

14

12

10

8

6

4

2

16

200 300 400 500 600 685

The tensile strength values refer to the (cold) as-rolled condition. For some grades, e.g. micro-alloyedfine-grain steels or high-carbonized and alloyed steels, the limit values will vary slightly.Please contact our Technical Customer Consulting Dept.

100

Strip thickness (mm)

Str

ip t

hic

knes

s (m

m)

Strips with a tensile strength ≤ 450 N/mm2

Strips with a tensile strength > 450 ≤ 650 N/mm2

Strips with a tensile strength > 650 ≤ 800 N/mm2

Strips with a tensile strength > 800 N/mm2 (≤ 1200 N/mm2)

200 300 400 500 600 685100

Strip thickness (mm)

Str

ip t

hic

knes

s (m

m)

200 300 400 500 600 685100

Strip thickness (mm)

Str

ip t

hic

knes

s (m

m)

200 300 400 500 600 685100

Strip thickness (mm)

Str

ip t

hic

knes

s (m

m)

Rolling and pickling program

Widths: 25 – 685mmMax. thicknesses: 16 mm(strip thicknesses < 1.5 mm byagreement)

Edge condition: As rolled edges (ME) Trimmed edges

Steel strip in cut lengths:Widths: 25 – 660 mmLengths: 1,000 – 18,000 mm

Inner coil diamter: approx. 500mm(optionally up to 610 mm)

Coil weight: by agreement

15Materials

Mild unalloyed steels

Material

General structural steels

Quality and stainless structural steels

Special structure steels

Tool steels

Special materials*

Heat-resistant materials*

Other steels

Corrosion-resistantsteels*

Mild unalloyed steel for cold-rolling 1614, Part 1

Mild unalloyed steel for direct cold forming (direct processing of hot strip) 1614, Part 2 EN 10111 111-77

17100 EN 10025 025-72

Quenched and tempered steels 17200 EN 10083 083-70Case-hardenable steels 17210 EN 10084 084-70Nitriding steels 17211 EN 10085 085-70Steels for flame and induction hardening 17212 EN 10086 086-70Hot-rolled strip for hardenable springs 17221 EN 10089 089-71Hot-rolled strip for cold-rolled steel strips for springs 17222 EN 10132-4 132-79Free cutting steels 1651 EN 10087 087-70Hot-rolled strip for welded gasbottles EN 10120 120-83Cold-upsetting and cold-extruding steels 1654 EN 10263 119-74Temperature-resistant steel plate and strip 17155 EN 10028-2 028-85Hot-rolled strip for steel pipes for pipelines for flammable liquids, gases 17172 EN 10208Hot-rolled strip for heat-resistant steel pipes 17177 EN 10217-2Compresses-hydrogen-resistant steels 590-61Cold ductile steels 17280 EN 10028-4 129-76Ship building steels To the guidelines of the

classification companyHardenable steels with special analyses To special specificationsSulphide-controlled molten steels To special specificationsCarbon steels for deep-drawable cold strip To special specificationsHot-rolled strip for deep-drawable cold-rolled spring steels To special specifications

Micro-alloyed fine-grain steels for cold-forming (HSM-qualities) EN 10149 092-90 149-80Weather-resistant structural steels (Resista steels) EN 10155 087-81 155-80Boron-alloyed case-hardened and quenched and tempered steels (HLB Qualities) 10083-3

unalloyed tool steels 17350 EN ISO 4957 096-79alloyed cold-working steels 17350 EN ISO 4957 096-79alloyed hot-working steels 17350 EN ISO 4957 096-79

Antifriction bearing steels 17230 EN ISO 683-17 094-73Soft magnetic steels for direct current relays 17405

Heat-resistant alloys and variousnon-ferrous metals and their alloys To various specificationsIron alloys with special thermal elongation 385-57Non-magnetizeable steels 390-61High-strength martensitic hardening steels To various specifications

Heat transfer alloys 17470Heat-resistant rolling and forging steels EN 10095 470-76

Stainless steels 17440 EN 10088 400-88 088-86Hot-rolled strip for stainless steel springs 17224 EN 10151

DIN- EN- Mat. EuroStandard Standard list Standard

*These special alloys are rolled by Hoesch Hohenlimburg under subcontract

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2Hoesch Hohenlimburg GmbHNarrow Steel Strip DivisionOeger Strasse 120D-58119 HagenTel.: +49 (2334) 9123 91 or 91-0Fax: +49 (2334) 9133 69Technical Customer Consulting Department:Tel.: +49 (2334) 913253/2271/2295Fax: +49 (2334) 9133 58E-Mail: mittelband@hho.thyssenkrupp.comInternet: www.hoesch-hohenlimburg.de