Rolls - strojpoldi.eu · Besides steel, special Rolls are also made of grey, nodular or special...
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ROLLS
Transcript of Rolls - strojpoldi.eu · Besides steel, special Rolls are also made of grey, nodular or special...
Rolls
15 minutes from Václav Havel Airport Prague.
POLDI Steel Works was established in 1889. Themechanical engineering part of production dates backtothe1890’s.
Theproductionofforgedrollscommencedin1910.since then the technology of roll production has beendevelopedandperfectedwithintheplant.
Today’s product is based on generations ofexperienceaswellasmodernadvancedproductiontechnology.
in stRoJÍRny PolDi, a.s., rolls for cold rolling are madefromforgingssuppliedbycompanieswhichmeet stringent quality requirements. For themanufacturing of rolls, either steel from electric arc furnaces,vacuumdegassedorpossiblysteelmadein ladle furnace by secondary refining can be used. For special applications, electro-slag re-melted steel orvacuumre-meltedsteelcanbeused.
Inordertoachievethebestpropertiesfortherolls,ourownknow-howisusedbecauseheattreatmenthas a decisive influence on roll properties. Theroll barrel is hardened in a medium-frequencyinduction hardening machine. a machine for induction hardening of roll bearing seats is also available.
Inordertofullymeetrequirements,ourforgedrollsaremachinefinishedandgroundtotheCustomer’sdimensionsandsurfacequalityspecifications.
“Great history. Excellent future”since 1889
ManuFaCtuRing PRogRaM Rolls:
• Forgedworkrollsforcoldrollingofsheetsteel• Forgedworkrollsforcoldrollingofplates of non-ferrous metals• Back-uprollsforrollingstands• Straighteningrolls• Castimmersionrollsforgalvanizinglines• Rollsforspecialapplications
at stRoJÍRny PolDi, a.s., exaCting attention IS PAID TO quALITy. ALL ROLLS ARe SuBjeCTto sPeCiFiC tests thRoughout the entiRe PRoDuCtion CyCle. these tests inCluDe:
• ultrasonicinspectionforinherentdefects• Inspectionofthepurityandstructureof the steel• Inspectionofhardnessofthehardenedlayer withportablehardnesstestersbyequotip, Vickers,ShoreandRockwell• Measuringofinternalstresslevelsbyacoustic emission method• Dimensionalchecksandsurfacequality inspection•Othertestsaccordingtotherequestofour customers
teChnology FoR Roll MaChining
exactrequirementsandcomplexsetsofconditionsduring cold rolling of sheet metal results in rolls meeting the specifications for their usage. the requiredutilityvaluesareassuredby thedistinctchemicalcompositionofthesteel,selectiveuseofsteelmaking technology, heat treatment and the construction of the rolls.
steel gRaDes FoR the ManuFaCtuRing oF Rolls aRe DiViDeD into FouR Main gRouPs:
• Low-alloyedsteel–lessthan4%Cr• Medium-alloyedsteel–about5%Cr• High-alloyedsteel–about12%Cr• High-speedsteel–about4%Crandmorethan 7%ofotheralloyingelements(V,W,Mo,Co)
Besidessteel, specialRollsarealsomadeofgrey,nodular or special cast iron
heat tReatMent
the induction hardening process of forged rolls isperformedinthemediumfrequencyinductionhardening plant, using frequencies of 160Hz to1100hz, automatic performance control and hard-ening temperature controls. in this plant, rolls up to a diameter of 630 mm and a length of 4200 mm can be hardened.
the depth of the hardened layer depends on thefrequencyselectedandthepropertiesofthesteel-grade that is used. This is usually between 6 – 20 mm.
after the induction hardening of the roll, it is tempered at low temperatures in temperingfurnaceswithforcedaircirculation.Thisoperationensures that the surface hardness is uniform, induced stress is released and the structures are stabilized.
rolling, pressing,moving...
www.strojpoldi.com
Member of
ManageMent
STROJÍRNY POLDI, a.s.Dubská 243, 272 03 Kladno – Dubí, Czech RepublicPhone: +420 313 115 110, Fax: +420 312 247 [email protected]
Maximum dimensions
Dia Length Mass
Work rolls for cold rolling of ferrous and non-ferrous metals
630 mm 4 200 mm 5 000 kg
Back-up rolls 630 mm 4 200 mm 5 000 kg
Straightening rolls 350 mm 4 200 mm 5 000 kg
Rolls for galvanizing lines 700 mm 4 200 mm 5 000 kg
Maximum dimensions
Dia Length Mass
Re-hardening of rolls in induction hardening machine
630 mm 4 200 mm 5 000 kg
Repair of damaged roll necks 630 mm 4 200 mm 5 000 kg
Quality CRiteRia FoR FoRgings
• Adherencetothechemicalcomposition of steel, including contents of elements• Steelcleanliness• Forgingreduction• Requiredgrain• Suitablestructureandmechanical properties• Removalofinducedstressafterthe forging operation
Rollsareusuallypreserved,packedandshippedinwoodencasesoronwoodenpallets
15 minutes from Václav Havel Airport Prague.
Manufacturing potential of rolls
Servicesprovided
