ANCIENT IRON and STEEL (Part I)

IRON ANCIENT IRON METEORITES AND STEEL (Part I)

1 CHEMICAL COMPOSITION TYPES OF METEORITES OF METEORIC IRON

¥ Aerolites (stone) Ni 0.07 - 60% ¥ P 0.08 - 1.5% ¥ Siderolites (mixture of stone and metal) Mn Tr. - 4% ¥ Co 0 - 3% ¥ Siderites (metal) S 0.08 - 5% ¥ Si 0.02 - 0.08% a) Hexahedrites (contain about 5.5 % Ni) b) Octahedrites (Widmenstatten structure, Cobalt concentration generally is about about 6-13 % Ni) 10% of that of Nickel. c) Ataxites (contain about 13-20 % Ni)

AS A FUNCTION NUMBER OF METEORS SOURCES OF NICKEL RICH OF Ni CONTENT IRON

¥ Iron meteorites that are classiﬁed as 75 hexahendrites. ¥ Telluric or terrestrial iron found in native iron-

50 bearing basalts (Greenland) Number ¥ Smelting of nickeliferous ores: 25 Pentlandite: (Ni,Fe)9S8

Garnierite: (ni,Mg)3SiO2(OH)4 0 4 8 12 16 20 24 28

2 ESTIMATION OF METEORIC IRON ANATOLIAN EVIDENCE OF ¥ Estimated that 10,000 tons/year of all types of IRON meteorite fall on earth. ¥ 30% land makes available amount to 3,000 ¥ Anatolian iron artifacts predating 1200 BC tons/year are: EBA (10), MBA (4)m Hittite (19) ¥ The ratio of metallic meteorite is 1:9; which ¥ Textual references from Bogazkoy tablets describe actual smelting of iron from its makes 300 tons/year meteoric iron describe actual smelting of iron from its ores. ¥ Maybe 1% of this was available for the people ¥ Maybe 1% of this was available for the people ¥ A clear distinction was made for meteoric of Near East region. Thus only 2 tons/year. iron (AN.BAR GE6) and for smelted iron ¥ However, large proportion of this iron was in (AN.BAR) the form of dust and burn in the atmosphere.

IRON ARTIFACTS FROM ANATOLIA PREDATING 1000 BC

Site Object Date Comment Tilmen Bracelet Early 3rd Mil BC No analysis Alacahöyük Dagger EBA II Low Ni “ Pins EBA II 2.7 % Ni “ Necklace EBA II No analysis Alacahöyük: 2800-2500 BC, Low Ni. Anatolian Civilizations Museum, Ankara “ Knife EBA II No analysis Troia Mace head 2800-2500 BC Ore/bloom ? Tarsus Iron Lump 2400-2100 BC No analysis Alisar Pin fragment 1900-1700 BC No analysis Kusura Metal fragment 1800-1600 BC No analysis Alacahöyük Assorted fragments 1800-1200 BC Two metallographic study Boğazköy Assorted pieces 1450-1200 BC No analysis Korucutepe Iron piece 1400-1200 BC No analysis Hittite Sword: Blade is steel, handle is bronze. Essen Ruhr Museum Tell Atchana Iron piece 1450-1200 BC No analysis

3 IRON DAGGER FROM Karagündüz Necrapole, Van. 11th and 10th Century BC. TUTANKHANUM’S TOMB

EARLY IRON ARTIFACTS FROM TERMS USED FOR IRON IN ANATOLIA MESOPOTAMIA AND ANATOLIA

3rs Mil. BC KU.AN Sumerian Mesopotamia 2000-1500 BC parzillu Akkadian Mosopotamia amatum Akkadian Anatolia AN.BAR Sumerian Mesopotamia KU.AN Sumerian Anatolia 1500-1000 BC amutum, habalkinuAkkadian Anatolia (Mitanni) parzilu Akkadian Anatolia(Boğazköy) AN.BAR Sumerian Mesop. Anatolia habalki Hittite Anatolia 1000-500 BC parzilu Akkadian Mesopotamia AN.BAR Sumerian Mesop. Anatolia Yalçõn Ü., (1999)

4 LOCALE OF THE FIRST IRON TYPES OF IRON IN SMELTING HITTITE TEXTS ¥ North Central Black Sea (Paplogonia and Amisus) regions has been very critical metallurgical center through out history. ¥ AN.BAR Iron (smelted) ¥ During EBA: Jason and the Argonauts were searching for the golden ﬂeece. ¥ AN.BAR GE6 Iron (meteoric?) ¥ During MBA: Halizoni in Homer’s book was ¥ AN.BAR SIG Good iron 5 looking for silver. ¥ AN.BAR BABBAR White iron? ¥ During IA: Strabo’s Geography mentions Chalybs mastering smelting of iron from the ore.

STRABO’S MAP OF POSSIBLE ORIGINS FOR PAPHLAGONIS SMELTED IRON

¥ Iron ore hematite (Fe2O3) is added as a ﬂuxing agent during the smelting of siliceous iron lead and copper ores. ¥ In such operations small fragments of ductile iron “bears” are formed in the furnace and may also contain some lead or copper. ¥ Many such examples are recovered sine 12th century BC.

5 HATTUSHILI III’S (1282-1250 BC) HITTITE RITUAL FOR BUILDING A HOUSE LETTER TO AN ASSYRIAN KING “The diorite they brought from the earth. The ….concerning the good iron which you black iron of the heaven they brought from mentioned in your letter, the store in heaven. Copper and bronze they brought from Kizzuwatna has run out of good iron. I wrote mount Taggata in Alasia (Cyprus)……” you that it is not a suitable time to produce iron. They will produce iron but they have In Akkadian, Sumerian, Egyptian and Hittite, not ﬁnished yet. When they have ﬁnished, I iron derives from the original phrase “metal from heaven” will send it to you. Now I am sending you (sword/dagger) point…...

EXPANSION OF IRON WORKING IRON ORES ¥ Believed to have been started somewhere in Anatolian-Iranian highlands during the period Name Formula % Iron 1500 - 1000 BC. ¥ By 1000 BC, penetrated to the coast of Palestine. Hematite Fe2O3 70 ¥ Phoenicians contributed in the expansion of this Magnetite Fe O 72 technology to western Mediterranean. 3 4

Greece 900 BC Limonite Fe2O3.H2O 65 Britain 500 BC Pyrite FeS 47 Nigeria 350 BC 2 Central Africa 500 AD Pyrrhotite Fe7S8 60 South Africa 1000 AD

6 REDUCTION PROCESS OF SMELTING OF IRON ORES HEMATITE ORE ¥ To smelt Cu and Pb, all that is needed is a mixture of sulphide and oxide ores and heat. 3Fe2O3 + CO 2Fe3O4 + CO2 ¥ To produce usable iron, metallurgist must employ only iron oxides, heat and carbon. Fe3O4 + CO 2FeO + CO2 2C + O2 2CO Fe O + 3CO 2Fe + 3CO 2 3 3 FeO + CO Fe + CO ¥ Charcoal provides both heat and the essential 2 CO gas. Workable “BLOOM IRON” can be obtained at 1100 - 1150 oC

ΔG 2Ag2O

Ag 2HgO DIRECT PROCESS AND THE 2Cu O SnO2 2 Hg PRODUCTION OF BLOOM IRON C 2PbO 2FeO Cu Pb ¥ CO as it ascents in the furnace, reduce the C CO 2 ore to a spongy iron mass with considerable Fe iron oxide and slag inclusions. Sn ¥ The silicates in the ore combines with some 2CO of the iron oxide and form the fusible slag

called “Fayalite” (FeO.SiO2)

T 710o C 1200o C

7 IRON SMELTING IRON SMELTING

AFRICAN IRON SMELTING IRON SMELTING FURNACE

8 EFFICIENCY OF EARLY IRON EFFICIENCY OF DIRECT METHOD FURNACES ¥ The iron ore used contained about 65-70 % iron. ¥ Only 10-15% of this iron extracted. 150 Kg Ore 25 Kg ¥ The rest of the iron in the ore is used to make liquid Bloom slag. 100 Kg ¥ Slag must contain over 60% iron in order to exist in Charcoal Forging liquid state at about 1100oC. ¥ Since early furnaces cannot go over 1200oC, and ste 12.5 Kg slag had to be liquid inorder to drain from the bloom, Usable Iron very small amount (about 15-20%) of the iron in the ore can be reduced.

TYPES OF SLAGS

¥ FAYALITHIC SLAG (Formed in bloomery furnace where wrought iron is produced) ¥ GLASSY SLAG (Formed in blast furnaces where cast iron is produced) ¥ FINARY SLAG (Formed in ﬁneries where cast iron is converted into wrought iron)

9 FAYALITHIC SLAG (Dolapdere) ANALYSIS OF SLAG ¥ Elemental composition is determined by Gen. Comp. AAS, ICPE, Neutron activation FeO: 60.5 SiO2: 22.0 ¥ Mineralogical analysis is determined by CaO: 3.75 Al2O3: 5.86 XRD, petrological microscope ¥ Microstructure is determined by optical microscopy, SEM

SPONGY BLOOM IRON BLOOM IRON

10 FORGING FORGING BLOOM IRON

Forging is shaping metal by ¥ “Fayalite” (FeOSiO2) and “wustite” (FeO) hammering. Most metals can be forged that remain in the bloom have to be hammered out at or above 1177 oC. At this even when cold. Iron, however, must temperature, iron grains coated with these be brought to a good red hot and substances can be forced out and the grains forged while still hot. Therefore, iron can be welded together. forging requires very different types of ¥ Addition of “apatite” (CaO-P2O5) in the tools. form of calcined bone lowers forging temperature as much as 100 oC.

BLACK SMITH FORGING IRON

11 BLACK SMITH FORGING HAMMER

WHY DID IRON REPLACED TENSILE STRENGTH OF SOME BRONZE EVEN THOUGH: METALS Bloomery iron 40,000 psi ¥ Bronze artifacts can be made quickly Pure copper 32,000 “ and easily by casting Work hardened iron 100,000 “ ¥ Bronze is remarkably more durable Cold worked 11 % Sn in Cu 120,000 “ 0.2-0.3 % carbon steel 60,000 “ against corrosion 1,2 % carbon steel 140,000 “ ¥ Bronze can be scrapped and recasted Cold worked 1.2% C Steel 245,000 “ repeatedly

12 IRON REPLACED BRONZE BECAUSE OF: Hardness of some ¥ Carburization (case hardening) metals ¥ Heat treatment of steel (quenching) ¥ Tempering of quenched steel

STRUCTURE OF IRON ¥ Crystal structure of iron (α iron) at room temperature is BCC. BCC structure van accept only 1.4 carbon atoms per 1000 Fe atoms. ¥ At 910 oC, BCC arrangement changes to FCC structure. The FCC structure can accept 96 carbon atoms per 1000 iron atoms. ¥ If more carbon atoms than allowed is present, extra carbon will react with iron to form “cementite” (iron carbide: Fe3C). Greater the amount of cementite, greater will be the hardness, strength and brittleness.

13 UNIT CELLS OF IRON FORMS

FORMATION OF CEMENTITE (IRON CARBIDE) CARBURIZATION OF IRON ¥ Known also as cementation or case When more carbon atom then hardening is a process that is carried out allowed is present in iron, the extra above 900 oC where iron object is heated carbon will react with some Fe atoms for a long time covered with carbon. and form cementite (iron carbide) ¥ At 950 oC, carbon can in nine hours diffuse (Fe3C). Cementite introduces greater as much as 1.5 mm into the iron reaching hardness, strength and brittleness to about 0.5 % carbon concentration. The rate iron. of diffusion increases with increasing temperature.

14 MODERN CARBURIZATION OF IRON PERLITE ¥ Perlite is not a phase but an alternating layers o ¥ At temperatures above 910 oC, the micro- of ferrite (88 % by mass) and cementite (12 structure of steel is known as “austenite”. % by weight). o ¥ When temperature falls below 727 oC, ¥ Ferrite is a comparatively soft and ductile austenite breaks down into material. Perlite is a hard and much less

a) “Ferrite” (pure Fe) ductile material. Cementite (Fe3C), however, is extremely hard and brittle material. b) “Cementite” (Iron carbide, Fe3C) ¥ Alternating layers of ferrite and cementite is known as the “perlite” structure.

PERLITE STRUCTURE

15 CARBON CONTENT OF IRON When iron contains ¥ When the austenite (g iron) containing 0.8 0.80% % carbon is cooled below 723 oC, 100 % laminated structure of perlite forms which is carbon ferrite (a iron) and cementite (Fe3C) upon ¥ Steels that contain less than 0.8% carbon are cooling, called “Hypoeutoctoid” steels. 100% ¥ Steels that contain between 0.8-2.0 % 100% carbon are called “Hypereutoctoid” steels perlite will form

Iron that Iron that contains contains less than more than 0.8 % 0.8 % carbon. carbon. Hypoeu- Hypereu- toctoid toctoid steel steel

16 CARBON CONTENT OF STEEL EFFECT OF CARBON CONTENT ON THE STRUCTURE OF STEEL As the carbon content of steel increases up to 0.8 %, the amount of ferrite decreases where as Hypoeutectoid Steel Hypereutectoid steel pearlite increases causing signiﬁcant increase in 100 hardness and tensile strength but decrease in Cementite ductility (elongation). In hypereutoctoid steels Ferrite (carbon content > 0.08 %), increasing carbon 50 content decreases pearlite but increases the Percentage amount of cementite. The result is further increase in hardness but little effect on ductility 0 0.4 0.8 and tensile strength. % Carbon Content

BESSEMER PROCESS BESSEMER PROCESS

17 FORMS OF IRON DIFFERENCES BETWEEN BLOOMERY AND BLAST FURNACE o CAST IRON Decarburization ¥ Increase in temperature (1300 - 1400 C) From Blast Furnace ¥ Higher fuel to ore ratio yields CO/CO2 ratio M.P. 1130oC 1,5-4.5 % C over 90%. Bessemer STEEL ¥ Constituents of slag fayalite (Fe2SiO4) and Process o M.P. 1400 C wustite (FeO) reduce to metallic iron. 0.1-0.9 % C wustite (FeO) reduce to metallic iron.

WROUGHT IRON ¥ Lime and/or clay added as ﬂux to create slag From Bloomery Cementation M.P 1535o C 0.06 % C Carburization