alloying elements in steel
TRANSCRIPT
-
7/29/2019 Alloying Elements in Steel
1/3
MACSTEEL - SPECIAL STEELS CATALOGUE
LeaRoad Tel:(011)897-5000
Dunswart Fax:(011)918-1125
POBox6130,Dunswart1508 Email:[email protected]
SouthAfrica Web:www.macsteel.co.za
AdivisionofMacsteelServiceCentreSA(Pty)Ltd:Reg.No2005/016292/07
Page1of3
SomefactsaboutAlloyingandaccompanyingelementsinsteel.
Al.Aluminium
Thisisthemostpowerfulde-oxidiserusedwhichalsocombineswithnitrogen,therebyreducingthesusceptibilitytostrainageing.Smalladditionsassistfine-grainedstructure.Asaluminiumformsveryhardnitrideswithnitrogen,itisusuallyanalloyingelementinnitridingsteels.Aluminiumimprovesthescaleresistanceandisthereforeoftenusedasanalloyingelementinferriticheatresistingsteels.
C.Carbon
Carbonisthemostimportantandinfluentialalloyingelementinsteel.InadditiontoCarboneveryunalloyedsteelcontainsSilicon,ManganesePhosphorusandSulphurwhichoccurunintentionallyduringmanufacture.TheadditionoffurtheralloyingelementstoachievespecialeffectsandintentionalincreaseofManganeseandSiliconcontents,resultsinalloysteel.WithincreasedCarboncontentthestrengthandhardenabilityofsteelincreasebutitsductility,forgeabilityandmachineabilityreduces.Thecarboncontentinsteelhasvirtuallynoeffectonthesteelscorrosionresistanceto
water,acidsandhotgasses.
Cr.Chromium
Chromiumincreasesthehardenabilityofsteelwhiletheductilityiseffectedminimally.HigherChromecontentinsteelincreasesitscorrosionresistance,andbyformingcarbidestheedgeholdingqualityofsteelincreases.Thetensilestrengthofsteelincreasesby8-100N/mm'2forevery1%chromeadded.Theyieldstrengthalsoincreasesbutthenotchimpactvaluereduces.
Mn.Manganese
ManganeseincreasesthestrengthofsteeltoalesserdegreethanCarbonwhileitfavourablyinfluencestheforgeability,weldabilityandmarkedlyincreasesthehardnesspenetrationdepth.
-
7/29/2019 Alloying Elements in Steel
2/3
MACSTEEL - SPECIAL STEELS CATALOGUE
LeaRoad Tel:(011)897-5000
Dunswart Fax:(011)918-1125
POBox6130,Dunswart1508 Email:[email protected]
SouthAfrica Web:www.macsteel.co.za
AdivisionofMacsteelServiceCentreSA(Pty)Ltd:Reg.No2005/016292/07
Page2of3
Mo.Molybdenum
WhileMolybdenumimprovesthetensilestrengthandincreasestheheatresistanceandweldabilityofsteel,theforgeabilityofsteelwithhighmolybdenum,contentdecreases.WhenusedincombinationwithChromiumandNickel,Molybdenummayproducehighyieldpointsandtensilestrengthvalues.
Ni.Nickel
ByaddingNickeltosteelthenotchtoughnessisincreasedsignificantlyandisthereforealloyedforincreasingtoughnessincase-hardening,heat-treatableandsubzerotoughnesssteels.NickelcombinedwithChromiumensuresgoodthroughhardening.Chrome-NickelsteelsareStainless,heatresistantandresistanttoscaling.Nickeldoesnotimpairtheweldingpropertiesofsteel.
P.Phosphorus
PhosphorusisnormallyregardedasbeingdetrimentaltosteelandeveryendeavouristhereforemadetokeepPhosphoruscontentinhighgrade
steelstoamaximumof0.03to0.05%.
Pb.Lead
Leadisaddedinfreecuttingsteelsinamountsof0.20-0.50%.Becauseofitsfinehomogenousdistribution,formationofshorterchipsandcleanfacesofcutisachieved,thusimprovingmachineability.Thestatedleadcontentdoesnoteffectthemechanicalpropertiesofthesteel.
SSulphur
Sulphurproducesthemostpronouncedsegregationofallsteelaccompanyingelements.Itleadstoredshortnessorhotshortness.Sulphurisaddedtosteelsforautomaticmachininginquantitiesofupto0.40%.Thisreducesthefrictiononthetoolcuttingedgesbymeansoflubricatingaction.therebyincreasingtoollife.Italsoproducesshorterchipsduringmachining.Sulphuralsoincreasessusceptibilitytoweldingcracksinsteel.
-
7/29/2019 Alloying Elements in Steel
3/3
MACSTEEL - SPECIAL STEELS CATALOGUE
LeaRoad Tel:(011)897-5000
Dunswart Fax:(011)918-1125
POBox6130,Dunswart1508 Email:[email protected]
SouthAfrica Web:www.macsteel.co.za
AdivisionofMacsteelServiceCentreSA(Pty)Ltd:Reg.No2005/016292/07
Page3of3
Si.Silicon
Silicon,likeManganeseiscontainedinallsteelasironorecontainsSiliconinvariousquantities,dependingonoverallcomposition.Siliconisalsoabsorbedfromthefurnacerefractoryliningsduringthemeltingprocess.However,onlysteelscontainingmorethan0.40%ofSiliconarecalledSiliconSteels.Siliconisadeoxidiserandpromotesgraphiteprecipitation,italsoincreasesthestrengthandwearresistanceofsteelwhilesignificantlyincreasingtheelasticlimit,thusbeingausefulalloyingelementinspringsteels.BecauseofSiliconsabilitytogreatlyreduceelectricalconductivity,extensiveuseismadeofitinelectricalsteels.
V.Vanadium
Vanadiumisusedasaprimarygrainrefinerinthemanufactureofsteel.Itisalsoastrongcarbideformer,thusprovidingincreasedwearresistance,edgeholdingandhightemperaturestrength.Vanadiumisthereforeusedprimarilyasanalloyingelementinhighspeed,hotformingandcreepresistantsteels
Althougheverycarehasbeentakeninthecompilationofthisbrochure,whichisfor
informationonly,noresponsibilitycanbeacceptedforinaccuracies.