1

ANCIENT IRONANCIENT IRONAND STEELAND STEEL

(Part(Part I)I)

IRONMETEORITES

2

TYPES OF METEORITESTYPES OF METEORITES

•• Aerolites (stone)Aerolites (stone)

•• Siderolites (mixture of stone and metal)Siderolites (mixture of stone and metal)

•• Siderites (metal)Siderites (metal)

a) Hexahedrites (contain about 5.5 % Ni)a) Hexahedrites (contain about 5.5 % Ni)

b) Octahedrites (Widmenstatten structure,b) Octahedrites (Widmenstatten structure,

about 6-13 % Ni) about 6-13 % Ni)

c) Ataxites (contain about 13-20 % Ni)c) Ataxites (contain about 13-20 % Ni)

CHEMICAL COMPOSITIONCHEMICAL COMPOSITIONOF METEORIC IRONOF METEORIC IRON

NiNi 0.07 - 60%0.07 - 60%

MnMn TrTr. - 4%. - 4%

SS 0.08 - 5% 0.08 - 5%

•• PP 0.08 - 1.5% 0.08 - 1.5%

•• Co 0 - 3%Co 0 - 3%

•• SiSi 0.02 - 0.08% 0.02 - 0.08%

Cobalt concentration generally is aboutCobalt concentration generally is about10% of that of Nickel.10% of that of Nickel.

AS A FUNCTION NUMBER OF METEORSAS A FUNCTION NUMBER OF METEORSOF Ni CONTENTOF Ni CONTENT

0 4 8 12 16 20 24 28

Num

ber

25

50

75

SOURCES OF NICKEL RICHSOURCES OF NICKEL RICHIRONIRON

•• Iron meteorites that are classified asIron meteorites that are classified ashexahendriteshexahendrites..

•• Telluric or terrestrial iron found in native iron-Telluric or terrestrial iron found in native iron-bearing basalts (Greenland)bearing basalts (Greenland)

•• Smelting of Smelting of nickeliferous nickeliferous ores:ores:

PentlanditePentlandite: (Ni,Fe): (Ni,Fe)99SS88

Garnierite: (Garnierite: (nini,Mg),Mg)33SiOSiO22(OH)(OH)44

3

ESTIMATION OF METEORIC IRONESTIMATION OF METEORIC IRON

•• Estimated that 10,000 tons/year of all types ofEstimated that 10,000 tons/year of all types ofmeteorite fall on earth.meteorite fall on earth.

•• 30% land makes available amount to 3,00030% land makes available amount to 3,000tons/yeartons/year

•• The ratio of metallic meteorite is 1:9; whichThe ratio of metallic meteorite is 1:9; whichmakes 300 tons/year meteoric ironmakes 300 tons/year meteoric iron

•• Maybe 1% of this was available for the peopleMaybe 1% of this was available for the peopleof Near East region. Thus only 2 tons/year.of Near East region. Thus only 2 tons/year.

•• However, large proportion of this iron was inHowever, large proportion of this iron was inthe form of dust and burn in the atmosphere.the form of dust and burn in the atmosphere.

ANATOLIAN EVIDENCE OFANATOLIAN EVIDENCE OFIRONIRON

•• Anatolian iron artifacts predating 1200 BCAnatolian iron artifacts predating 1200 BCare: EBA (10), MBA (4)m Hittite (19)are: EBA (10), MBA (4)m Hittite (19)

•• Textual references from Bogazkoy tabletsTextual references from Bogazkoy tabletsdescribe actual smelting of iron from itsdescribe actual smelting of iron from itsores.ores.

•• A clear distinction was made for meteoricA clear distinction was made for meteoriciron (AN.BAR GEiron (AN.BAR GE66) and for smelted iron) and for smelted iron(AN.BAR)(AN.BAR)

IRON ARTIFACTS FROM ANATOLIAIRON ARTIFACTS FROM ANATOLIAPREDATING 1000 BCPREDATING 1000 BC

No analysisNo analysis1450-1200 BC1450-1200 BCIron pieceIron pieceTell AtchanaTell Atchana

No analysisNo analysis1400-1200 BC1400-1200 BCIron pieceIron pieceKorucutepeKorucutepe

No analysisNo analysis1450-1200 BC1450-1200 BCAssorted piecesAssorted piecesBoBoğğazköyazköy

Two metallographic studyTwo metallographic study1800-1200 BC1800-1200 BCAssorted fragmentsAssorted fragmentsAlacahöyükAlacahöyük

No analysisNo analysis2400-2100 BC2400-2100 BCIron LumpIron LumpTarsusTarsus

No analysisNo analysis1900-1700 BC1900-1700 BCPin fragmentPin fragmentAlisarAlisar

No analysisNo analysis1800-1600 BC1800-1600 BCMetal fragmentMetal fragmentKusuraKusura

CommentCommentDateDateObjectObjectSiteSite

No analysisNo analysisEBA IIEBA IINecklaceNecklace““

No analysisNo analysisEBA IIEBA IIKnifeKnife““

Ore/bloom ?Ore/bloom ?2800-2500 BC2800-2500 BCMace headMace headTroiaTroia

Low NiLow NiEBA IIEBA IIDaggerDaggerAlacahöyükAlacahöyük

2.7 % Ni2.7 % NiEBA IIEBA IIPinsPins““

No analysisNo analysis Early 3rd Mil BC Early 3rd Mil BCBraceletBraceletTilmenTilmen

Alacahöyük: 2800-2500 BC, Low Ni. Anatolian Civilizations Museum, AnkaraAlacahöyük: 2800-2500 BC, Low Ni. Anatolian Civilizations Museum, Ankara

Hittite Sword: Blade is steel, handle is bronze. Essen Ruhr MuseumHittite Sword: Blade is steel, handle is bronze. Essen Ruhr Museum

4

Karagündüz Karagündüz NecrapoleNecrapole, Van., Van.11th and 10th Century BC.11th and 10th Century BC.

IRON DAGGER FROMIRON DAGGER FROMTUTANKHANUMTUTANKHANUM’’S TOMBS TOMB

TERMS USED FOR IRON INTERMS USED FOR IRON INMESOPOTAMIA AND ANATOLIAMESOPOTAMIA AND ANATOLIA

3rs Mil. BC3rs Mil. BC KU.ANKU.AN SumerianSumerian MesopotamiaMesopotamia

2000-1500 BC2000-1500 BC parzilluparzillu AkkadianAkkadian MosopotamiaMosopotamia

amatumamatum AkkadianAkkadian AnatoliaAnatolia

AN.BARAN.BAR SumerianSumerian MesopotamiaMesopotamia

KU.ANKU.AN SumerianSumerian AnatoliaAnatolia

1500-1000 BC1500-1000 BC amutum, habalkinuamutum, habalkinuAkkadianAkkadian Anatolia (Mitanni)Anatolia (Mitanni)

parziluparzilu AkkadianAkkadian Anatolia(BoAnatolia(Boğğazköy)azköy)

AN.BARAN.BAR SumerianSumerian Mesop. AnatoliaMesop. Anatolia

habalkihabalki HittiteHittite AnatoliaAnatolia

1000-500 BC1000-500 BC parziluparzilu AkkadianAkkadian MesopotamiaMesopotamia

AN.BARAN.BAR SumerianSumerian Mesop. AnatoliaMesop. Anatolia

EARLY IRON ARTIFACTS FROMEARLY IRON ARTIFACTS FROMANATOLIAANATOLIA

YalçYalçıın Ü., (1999)n Ü., (1999)

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TYPES OF IRON INTYPES OF IRON INHITTITE TEXTSHITTITE TEXTS

•• AN.BARAN.BAR Iron (smelted)Iron (smelted)

•• AN.BAR GEAN.BAR GE66 Iron (meteoric?)Iron (meteoric?)

•• AN.BAR SIGAN.BAR SIG55 Good ironGood iron

•• AN.BAR BABBARAN.BAR BABBAR White iron?White iron?

LOCALE OF THE FIRST IRONLOCALE OF THE FIRST IRONSMELTINGSMELTING

•• North Central Black Sea (North Central Black Sea (Paplogonia Paplogonia andandAmisus) regions has been very criticalAmisus) regions has been very criticalmetallurgical center through out history.metallurgical center through out history.

•• During EBA: Jason and the Argonauts wereDuring EBA: Jason and the Argonauts weresearching for the golden fleece.searching for the golden fleece.

•• During MBA: Halizoni in HomerDuring MBA: Halizoni in Homer’’s book wass book waslooking for silver.looking for silver.

•• During IA: StraboDuring IA: Strabo’’s Geography mentionss Geography mentionsChalybs mastering smelting of iron from the ore.Chalybs mastering smelting of iron from the ore.

STRABOSTRABO’’S MAP OFS MAP OFPAPHLAGONISPAPHLAGONIS

POSSIBLE ORIGINS FORPOSSIBLE ORIGINS FORSMELTED IRONSMELTED IRON

•• Iron ore hematite (FeIron ore hematite (Fe22OO33) is added as a fluxing) is added as a fluxingagent during the smelting of siliceous iron leadagent during the smelting of siliceous iron leadand copper ores.and copper ores.

•• In such operations small fragments of ductileIn such operations small fragments of ductileiron iron ““bearsbears”” are formed in the furnace and may are formed in the furnace and mayalso contain some lead or copper.also contain some lead or copper.

•• Many such examples are recovered sine 12thMany such examples are recovered sine 12thcentury BC.century BC.

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HATTUSHILI IIIHATTUSHILI III’’S (1282-1250 BC)S (1282-1250 BC)LETTER TO AN ASSYRIAN KINGLETTER TO AN ASSYRIAN KING

…….concerning the good iron which you.concerning the good iron which youmentioned in your letter, the store inmentioned in your letter, the store inKizzuwatna has run out of good iron. I wroteKizzuwatna has run out of good iron. I wroteyou that it is not a suitable time to produceyou that it is not a suitable time to produceiron. They will produce iron but they haveiron. They will produce iron but they havenot finished yet. When they have finished, Inot finished yet. When they have finished, Iwill send it to you. Now I am sending youwill send it to you. Now I am sending you(sword/dagger) point(sword/dagger) point……......

HITTITE RITUAL FORHITTITE RITUAL FORBUILDING A HOUSEBUILDING A HOUSE

““The diorite they brought from the earth. TheThe diorite they brought from the earth. Theblack iron of the heaven they brought fromblack iron of the heaven they brought fromheaven. Copper and bronze they brought fromheaven. Copper and bronze they brought frommount mount Taggata Taggata in in Alasia Alasia (Cyprus)(Cyprus)……”……”

In Akkadian, Sumerian, Egyptian and Hittite,In Akkadian, Sumerian, Egyptian and Hittite,iron derives from the original phrase iron derives from the original phrase ““metalmetalfrom heavenfrom heaven””

EXPANSION OF IRON WORKINGEXPANSION OF IRON WORKING

•• Believed to have been started somewhere inBelieved to have been started somewhere inAnatolian-Iranian highlands during the periodAnatolian-Iranian highlands during the period1500 - 1000 BC.1500 - 1000 BC.

•• By 1000 BC, penetrated to the coast of Palestine.By 1000 BC, penetrated to the coast of Palestine.•• Phoenicians contributed in the expansion of thisPhoenicians contributed in the expansion of this

technology to western Mediterranean.technology to western Mediterranean.GreeceGreece 900 BC900 BCBritainBritain 500 BC500 BCNigeriaNigeria 350 BC350 BCCentral AfricaCentral Africa 500 AD500 ADSouth AfricaSouth Africa 1000 AD 1000 AD

IRON ORESIRON ORES

6060FeFe77SS88PyrrhotitePyrrhotite

4747FeSFeS22PyritePyrite

6565FeFe22OO33.H.H22OOLimoniteLimonite

7272FeFe33OO44MagnetiteMagnetite

7070FeFe22OO33 Hematite Hematite

% Iron% IronFormulaFormulaNameName

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SMELTING OF IRON ORESSMELTING OF IRON ORES•• To smelt Cu and Pb, all that is needed is aTo smelt Cu and Pb, all that is needed is a

mixture of sulphide and oxide ores and heat.mixture of sulphide and oxide ores and heat.

•• To produce usable iron, metallurgist mustTo produce usable iron, metallurgist mustemploy only iron oxides, heat and carbon.employ only iron oxides, heat and carbon.

2C + O2C + O22 2CO 2CO

Fe Fe22OO3 3 + 3CO 2Fe + 3CO+ 3CO 2Fe + 3CO33

•• Charcoal provides both heat and the essentialCharcoal provides both heat and the essentialCO gas. Workable CO gas. Workable ““BLOOM IRONBLOOM IRON”” can be can beobtained at 1100 - 1150 obtained at 1100 - 1150 ooCC

REDUCTION PROCESS OFREDUCTION PROCESS OFHEMATITE OREHEMATITE ORE

3Fe3Fe22OO33 + + COCO 2Fe2Fe33OO44 + CO + CO22

FeFe33OO44 + CO + CO 2FeO + CO2FeO + CO22

FeO + CO FeO + CO Fe + CO Fe + CO22

710710oo C C 12001200oo C C

2Ag2Ag22OO

2HgO2HgO2Cu2Cu22OOSnOSnO22

2PbO2PbO

2FeO2FeO

COCO22

2CO2CO

AgAg

HgHg

CC

CuCuPbPb

CC

FeFeSn

TT

ΔΔGG

DIRECT PROCESS AND THEDIRECT PROCESS AND THEPRODUCTION OF BLOOM IRONPRODUCTION OF BLOOM IRON

•• CO as it ascents in the furnace, reduce theCO as it ascents in the furnace, reduce theore to a spongy iron mass with considerableore to a spongy iron mass with considerableiron oxide and slag inclusions.iron oxide and slag inclusions.

•• The silicates in the ore combines with someThe silicates in the ore combines with someof the iron oxide and form the fusible slagof the iron oxide and form the fusible slagcalled called ““FayaliteFayalite”” (FeO.SiO (FeO.SiO22))

8

IRON SMELTINGIRON SMELTING IRON SMELTINGIRON SMELTING

IRON SMELTINGIRON SMELTINGAFRICAN IRON SMELTINGAFRICAN IRON SMELTING

FURNACEFURNACE

9

EFFICIENCY OF EARLY IRONEFFICIENCY OF EARLY IRONFURNACESFURNACES

150 Kg Ore

100 KgCharcoal

25 KgBloom

12.5 KgUsable Iron

ForgingForging

EFFICIENCY OF DIRECT METHODEFFICIENCY OF DIRECT METHOD

•• The iron ore used contained about 65-70 % iron.The iron ore used contained about 65-70 % iron.

•• Only 10-15% of this ironOnly 10-15% of this iron extracted.extracted.

•• The rest of the iron in the ore is used to make liquidThe rest of the iron in the ore is used to make liquidslag.slag.

•• Slag must contain over 60% iron in order toSlag must contain over 60% iron in order to exist inexist inliquid state at about 1100liquid state at about 1100ooC.C.

•• Since early furnaces cannot go overSince early furnaces cannot go over 12001200ooC, and C, and stesteslag had to be liquid slag had to be liquid inorder inorder to drain from the bloom,to drain from the bloom,very small amount (about 15-20%) of the iron in thevery small amount (about 15-20%) of the iron in theore can be reduced.ore can be reduced.

TYPES OF SLAGSTYPES OF SLAGS

•• FAYALITHIC SLAG (Formed in bloomeryFAYALITHIC SLAG (Formed in bloomeryfurnace where wrought iron is produced)furnace where wrought iron is produced)

•• GLASSY SLAG (Formed in blast furnacesGLASSY SLAG (Formed in blast furnaceswhere cast iron is produced)where cast iron is produced)

•• FINARY SLAG (Formed in fineries whereFINARY SLAG (Formed in fineries wherecast iron is converted into wrought iron)cast iron is converted into wrought iron)

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ANALYSIS OF SLAGANALYSIS OF SLAG

•• Elemental composition is determined byElemental composition is determined byAAS, ICPE, Neutron activationAAS, ICPE, Neutron activation

•• Mineralogical analysis is determined byMineralogical analysis is determined byXRD, XRD, petrological petrological microscopemicroscope

•• Microstructure is determined by opticalMicrostructure is determined by opticalmicroscopy, SEMmicroscopy, SEM

FAYALITHIC SLAGFAYALITHIC SLAG ( (DolapdereDolapdere))

Gen. Comp.FeO: 60.5SiO2: 22.0CaO: 3.75

Al2O3: 5.86

SPONGY BLOOM IRONSPONGY BLOOM IRON BLOOM IRONBLOOM IRON

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FORGINGFORGING

Forging is shaping metal byForging is shaping metal byhammering. Most metals can be forgedhammering. Most metals can be forgedeven when cold. Iron, however, musteven when cold. Iron, however, mustbe brought to a good red hot andbe brought to a good red hot andforged while still hot. Therefore, ironforged while still hot. Therefore, ironforging requires very different types offorging requires very different types oftools.tools.

FORGING BLOOM IRONFORGING BLOOM IRON

•• ““FayaliteFayalite”” (FeOSiO (FeOSiO22) and ) and ““wustitewustite”” (FeO) (FeO)that remain in the bloom have to bethat remain in the bloom have to behammered out at or above 1177 hammered out at or above 1177 ooC. At thisC. At thistemperature, iron grains coated with thesetemperature, iron grains coated with thesesubstances can be forced out and the grainssubstances can be forced out and the grainscan be welded together.can be welded together.

•• Addition of Addition of ““apatiteapatite”” (CaO-P (CaO-P22OO55) in the) in theform of calcined bone lowers forgingform of calcined bone lowers forgingtemperature as much as 100 temperature as much as 100 ooC.C.

BLACKBLACKSMITHSMITH

FORGINGFORGINGIRONIRON

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BLACK SMITHBLACK SMITH FORGING HAMMERFORGING HAMMER

WHY DID IRON REPLACEDWHY DID IRON REPLACEDBRONZE EVEN THOUGH:BRONZE EVEN THOUGH:

•• Bronze artifacts can be made quicklyBronze artifacts can be made quicklyand easily by castingand easily by casting

•• Bronze is remarkably more durableBronze is remarkably more durableagainst corrosionagainst corrosion

•• Bronze can be scrapped and recastedBronze can be scrapped and recastedrepeatedlyrepeatedly

TENSILE STRENGTH OF SOMETENSILE STRENGTH OF SOMEMETALSMETALS

Bloomery ironBloomery iron 40,000 psi40,000 psiPure copperPure copper 32,000 32,000 ““Work hardened ironWork hardened iron 100,000 100,000 ““Cold worked 11 % Sn in Cu 120,000 Cold worked 11 % Sn in Cu 120,000 ““0.2-0.3 % carbon steel0.2-0.3 % carbon steel 60,000 60,000 ““1,2 % carbon steel 1,2 % carbon steel 140,000 140,000 ““Cold worked 1.2% C SteelCold worked 1.2% C Steel 245,000 245,000 ““

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IRON REPLACED BRONZEIRON REPLACED BRONZEBECAUSE OF:BECAUSE OF:

•• Carburization (case hardening)Carburization (case hardening)

•• Heat treatment of steel (quenching)Heat treatment of steel (quenching)

•• Tempering of quenched steelTempering of quenched steel

HardnessHardnessof someof somemetalsmetals

STRUCTURE OF IRONSTRUCTURE OF IRON•• Crystal structure of iron (Crystal structure of iron (αα iron) at room iron) at room

temperature is BCC. BCC structure van accepttemperature is BCC. BCC structure van acceptonly 1.4 carbon atoms per 1000 Fe atoms.only 1.4 carbon atoms per 1000 Fe atoms.

•• At 910 At 910 ooC, BCC arrangement changes to FCCC, BCC arrangement changes to FCCstructure. The FCC structure can accept 96structure. The FCC structure can accept 96carbon atoms per 1000 iron atoms.carbon atoms per 1000 iron atoms.

•• If more carbon atoms than allowed is present,If more carbon atoms than allowed is present,extra carbon will react with iron to formextra carbon will react with iron to form““cementitecementite”” (iron carbide: Fe (iron carbide: Fe33C). Greater theC). Greater theamount of cementite, greater will be theamount of cementite, greater will be thehardness, strength and brittleness.hardness, strength and brittleness.

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UNIT CELLS OF IRON FORMSUNIT CELLS OF IRON FORMS

FORMATION OF CEMENTITEFORMATION OF CEMENTITE(IRON CARBIDE)(IRON CARBIDE)

When more carbon atom thenWhen more carbon atom thenallowed is present in iron, the extraallowed is present in iron, the extracarbon will react with some Fe atomscarbon will react with some Fe atomsand form cementite (iron carbide)and form cementite (iron carbide)(Fe(Fe33C). Cementite introduces greaterC). Cementite introduces greaterhardness, strength and brittleness tohardness, strength and brittleness toiron.iron.

CARBURIZATION OF IRONCARBURIZATION OF IRON

•• Known also as cementation or caseKnown also as cementation or casehardening is a process that is carried outhardening is a process that is carried outabove 900above 900 o oC where iron object is heatedC where iron object is heatedfor a long time covered with carbon.for a long time covered with carbon.

•• At 950 At 950 ooC, carbon can in nine hours diffuseC, carbon can in nine hours diffuseas much as 1.5 mm into the iron reachingas much as 1.5 mm into the iron reachingabout 0.5 % carbon concentration. The rateabout 0.5 % carbon concentration. The rateof diffusion increases with increasingof diffusion increases with increasingtemperaturetemperature..

15

MODERN CARBURIZATION OF IRONMODERN CARBURIZATION OF IRON

•• At temperatures above 910 At temperatures above 910 ooC, the micro-C, the micro-structure of steel is known as structure of steel is known as ““austeniteaustenite””..

•• When temperature falls below 727 When temperature falls below 727 ooC,C,austenite breaks down intoaustenite breaks down into

a) a) ““FerriteFerrite”” (pure Fe) (pure Fe)

b) b) ““CementiteCementite”” (Iron carbide, Fe (Iron carbide, Fe33C)C)

•• Alternating layers of ferrite and cementite isAlternating layers of ferrite and cementite isknown as the known as the ““perliteperlite”” structure. structure.

PERLITEPERLITE

•• Perlite is not a phase but an alternating layersPerlite is not a phase but an alternating layersof ferrite (88 % by mass) and cementite (12of ferrite (88 % by mass) and cementite (12% by weight).% by weight).

•• Ferrite is a comparatively soft and ductileFerrite is a comparatively soft and ductilematerial. Perlite is a hard and much lessmaterial. Perlite is a hard and much lessductile material. Cementite (Feductile material. Cementite (Fe33C), however,C), however,is extremely hard and brittle material.is extremely hard and brittle material.

PERLITE STRUCTUREPERLITE STRUCTURE

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CARBON CONTENT OF IRONCARBON CONTENT OF IRON

•• When the austenite (When the austenite (gg iron) containing 0.8 iron) containing 0.8% carbon is cooled below 723 % carbon is cooled below 723 ooC, 100 %C, 100 %laminated structure of perlite forms which islaminated structure of perlite forms which isferrite (ferrite (aa iron) and cementite (Fe iron) and cementite (Fe33C)C)

•• Steels that contain less than 0.8% carbon areSteels that contain less than 0.8% carbon arecalled called ““HypoeutoctoidHypoeutoctoid”” steels. steels.

•• Steels that contain between 0.8-2.0 %Steels that contain between 0.8-2.0 %carbon are called carbon are called ““HypereutoctoidHypereutoctoid”” steels steels

When ironWhen ironcontainscontains0.80%0.80%carboncarbonuponupon

cooling,cooling,100%100%

perlite willperlite willformform

Iron thatIron thatcontainscontainsless thanless than

0.8 %0.8 %carbon.carbon.

Hypoeu-Hypoeu-toctoidtoctoidsteelsteel

Iron thatIron thatcontainscontains

more thanmore than0.8 %0.8 %

carbon.carbon.HypereuHypereu--toctoidtoctoidsteelsteel

17

CARBON CONTENT OF STEELCARBON CONTENT OF STEEL

As the carbon content of steel increases up toAs the carbon content of steel increases up to0.8 %, the amount of ferrite decreases where as0.8 %, the amount of ferrite decreases where aspearlite increases causing significant increase inpearlite increases causing significant increase inhardness and tensile strength but decrease inhardness and tensile strength but decrease inductility (elongation). In hypereutoctoid steelsductility (elongation). In hypereutoctoid steels(carbon content > 0.08 %), increasing carbon(carbon content > 0.08 %), increasing carboncontent decreases pearlite but increases thecontent decreases pearlite but increases theamount of cementite. The result is furtheramount of cementite. The result is furtherincrease in hardness but little effect on ductilityincrease in hardness but little effect on ductilityand tensile strength.and tensile strength.

EFFECT OF CARBON CONTENT ONEFFECT OF CARBON CONTENT ONTHE STRUCTURE OF STEELTHE STRUCTURE OF STEEL

0 0.4 0.8

50

100

Ferrite

Cementite

Hypoeutectoid Steel Hypereutectoid steel

% Carbon Content

Perc

enta

ge

BESSEMER PROCESSBESSEMER PROCESS BESSEMER PROCESSBESSEMER PROCESS

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FORMS OF IRONFORMS OF IRON

CAST IRONCAST IRON

WROUGHTWROUGHT IRON IRON

STEELSTEEL

From Blast Furnace From Blast Furnace

From BloomeryFrom Bloomery

Decarburization

Cementation

Carburization

BessemerProcess

M.P. 1130M.P. 1130ooCC1,5-4.5 % C1,5-4.5 % C

M.P 1535M.P 1535oo C C 0.06 % C 0.06 % C

M.P. 1400M.P. 1400oo C C0.1-0.9 % C0.1-0.9 % C

DIFFERENCES BETWEEN BLOOMERYDIFFERENCES BETWEEN BLOOMERYAND BLAST FURNACEAND BLAST FURNACE

•• Increase in temperature (1300 - 1400Increase in temperature (1300 - 1400ooC)C)

•• Higher fuel to ore ratio yields CO/COHigher fuel to ore ratio yields CO/CO22 ratio ratioover 90%.over 90%.

•• Constituents of slag fayalite (FeConstituents of slag fayalite (Fe22SiOSiO44) and) andwustite (FeO) reduce to metallic iron.wustite (FeO) reduce to metallic iron.

•• Lime and/or clay added as flux to create slagLime and/or clay added as flux to create slag