BN-K1ModelofCBNtoolsformachininghighhardnessrolls
Withthedevelopmentofrollingtechnologyandthefiercecompetitioninthe market,nomatterhotrollingorcoldrolling,thequalityrequirementsofrollsarevery strict,andtheirmainperformancerequirementsarestrength,hardness,heatresistance anddurability,aswellascertainimpacttoughness.Thehardnessoftherollworking layeritselfisveryhigh,sowhenturningtherollbody,therequirementsforcutting toolsaremorestringent,withthedevelopmentofcuttingtechnologytoolsmaterials havedevelopedfromhigh-speedsteelandcementedcarbideatthebeginningofthe 20thcenturytoceramictoolsandsuperhardtoolsmaterials,andtheheatresistance temperaturehasincreasedfrom500C~600Ctomorethan1200℃.Thecutting productivityhasbeenincreasedbymorethan100timesinlessthan100years,soit canbesaidthatthedevelopmentoftoolsmaterialsactuallyreflectsthedevelopment historyofcuttingrolltechnology.
Cementedcarbidetoolsmaterials:
Withtheincreaseofdomesticsteeloutputyearbyyear,theproduction proportionofrollsincreasescontinuouslythehardnessofsomekindsofrollsisabove HSD75Atthebeginning,thecommonlyusedtoolsformachiningcastironrollsis cementedcarbide,andthecommonlyusedtoolbrandisYG6,YG6X,butduetothe characteristicsofthematerial,thehardnessofitscementedcarbidecutterbodyis aboutHSD100.Becausethereisacertaingapbetweenthemachinedworkpieceand theknifeblock,itcanbeprocessedTherefore,itssuitableprocessingrangeisnodular castironwithlowhardness(belowHSD70)Forexample,iftheordinarycemented carbidetoolisusedtoprocesstherollssurfacewithhighhardness,duetothelarge hardnessdropbetweentherollsandthetools,theproblemreflectedisthatthetoolis soft,notwear-resistant,andcannotkeepaneyeontheedge,whichnotonlydoesnot goup,butalsoneedstobechangedfrequentlyandsharpened;iftherollswhose hardnessreachesHSD85orso,itisalmostimpossibletoprocess
Ceramictoolsmaterials:
Becausethehardnessoftherollbodyishigh,thecementedcarbidetoolis incompetent,andthentheceramictoolisusedtoprocesstherollTheceramicblade hasgoodhardnessandwearresistance,goodthermochemicalstabilityandoxidation resistancebetterthancementedcarbide.Itissuitablefortheprocessingofhigh hardnessmaterials,butceramictoolsaresensitivetoimpactandvibrationloads,so thelathemusthavegoodrigidity,sufficientpowerandspeedThedisadvantageof ceramictoolisbrittleness,lowtransversefracturestrengthandweakabilityto withstandimpactload,soceramictoolisabetterchoicewhenthecuttinghardnessis lowerthanHRC55andsmallfeedisused,butrollblankisgenerallyaccompaniedby castingdefectssuchasstomata,trachoma,sand,etc,whichiseasytocollapsewhen usingceramictools
Cubicboronnitridetoolmaterial:
ThesolidCBNtoolisusedtoprocesstherolltheCBNtoolhasgoodcutting performance,goodhardness,fractureresistanceandwearresistance.thetoolcan greatlyimprovethecuttingefficiencyofhighhardnessrollbodysurface,especially thenon-metallicadhesiveCBNtools,whosehardnessandimpactstrengtharesuitable forroughturningandfinishingofrolls,andarewidelyusedinhighhardnessroll cuttingForexample,CBNinsertBN-K1issuitablefortheprocessingofhigh hardnessandhighalloycastironrolls,whileBN-S20ismoresuitableforthe processingofforgedsteelrollsafterheattreatment.
Accordingtoexperience,thetoolmaterialisselectedaccordingtothehardness oftherollHotrollsorothernon-workrollslowerthanHSD70canbecutwith cementedcarbidetoolYG6,YG6X
Processingofhighhardnesscastironrolls:
FortheprocessingofcastironrollsaboveHSD75,becauseofthehighhardness oftheroll,therollblankisgenerallyaccompaniedbycastingdefectssuchasstomata, trachoma,sand,etc.,whichrequireshighimpactresistance,hightemperature resistanceandwearresistanceoftheblade.Atpresent,CBNinsertBN-K1is commonlyusedtoprocessthiskindofroll.Inadditiontotheexcellenthardnessand wearresistanceofCBNtools,thisbladehasgoodimpacttoughness,noteasyto collapse,canpullroughcarsonrollers,canwithstandlargecuttingdepthandhigh metalcuttingrate.
ExamplesofcastironrollsmachinedbyBN-K1toolsareasfollows:
TakethemachiningofNi-Cralloycastironrollsasanexample(seefigure)
Rollshardness:HSD80.
Machiningtools:BN-K1
Cuttingparameters:Ap=4mm,Fr=1mm/r,Vc=55m/min
Cuttingmethod:drycutting.
ThecomparisonbetweentheeffectofBN-K1andceramictoolisasfollows:
HalnnBN-K1
Otherbrandsofceramicinserts
Processingofcoldrollsofhighhardnessforgedsteel:
Thecuttingcharacteristicofforgedsteelcoldrollisdifferentfromthatofcasting roll,andthehardnessofforgedsteelcoldrollishigherthanthatofhotroll,soitis moredifficulttoturn.Onlyreasonableselectionofcuttingtoolscanensurethequality andmachiningefficiencyoftheworkpiece.Forexample,whenprocessingGCr15 rollingbearingsteelrollafterheattreatment,thecutterisBN-S20CBNtools,which ismadeofnon-metallicadhesiveandCBNpowder,whichfollowsthetoughnessof BN-K1tool,especiallyforthecoldrollofforgedsteelwithlongironfilings.When processingforgedsteelcoldroll,thewearresistanceisabout3timesthatofordinary CBNinserts
ExamplesofforgingsteelrollsmachinedbyBN-S20bladesareasfollows:
Machininghighspeedsteelrolls(asshowninfigure):
Hardness:HSD90
Machiningtool:BN-S20
Cuttingparameters:Fr=0.2mm/r,Vc=50m/min.
Cuttingmethod:drycutting.
ThecomparisonbetweentheeffectofBN-S20andcementedcarbideinsertisas follows:
toolsmaterial Processingbeat toolslife
HalnnBN-S20 2Hours 25Slotted/r
Otherbrandsofcementedcarbideinserts 12Hours 3Slotted/r
CuttingparametersofBN-S20toolformachiningforgedsteelcoldrollingwork roll:
（1）Themainresultsareasfollows:takethecoldrollofforgedsteel(hardness HRC67)asanexample:thecuttingdepthis4-7mm,thelinearspeedis90m/min,and theservicelifeis2.5timesthatoftheCBNinsertofaforeignbrand.
（2）Whenturningandrepairingthe9Cr2Mocoldrollingworkroll,usingBN-S20 canalsoachievegoodresults,thebladelifeismorethan4timesthatofthedomestic CBNinsertandtheknifewillnotcollapsewhenthechappedpartisencounteredin theturningrepairofthecoldroll,whichensuresthesafetyandeconomyoftheCBN insert.
（3）Repaircoldroll:BN-S20doesnotcollapsewhenitmeetschappedparts,which ensuresthesafetyandeconomyofCBNtools
（4）Surfacingrollturning:BN-S20insertcanbeusedtoprocessnickel-basedalloy surfacingandcobalt-basedalloysurfacingrolls.
