Metallurgy for the Non Metallurgist Lesson 1 A History of ... Sept 2013 Long Journey of Smiths.pdf · The Long Journey of Blacksmiths and Steel Making (a tapestry of historical metal

The Long Journey of Blacksmithsand Steel Making

(a tapestry of historical metal development)

Metallurgy for the Non Metallurgist

Lesson 1A History of Metals

September 25, 2013

Richard Boswell, P.E.Mechanical Engineer

Blacksmith

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Our Reference Document for this

class

ASM Course 0135Lesson 1

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About the PresenterRichard Boswell is a pressure vessel stress analyst, a test engineer, and a software developer conducting diverse projects in these areas. He was with Texaco Research for 2 years prior to joining a small consulting company that became Stress Engineering Services where he has been an owner for 30 of his 35+ years with the company.Richard began working Delayed Coke Drum projects in 1992 after years of field and lab testing with strain gages. Before coke drums he worked on FCCU designs and field monitoring of how they operate.Richard is an active blacksmith, a target shooter, and most recently a Harley Davidson enthusiast. He lives on a tree farm near Houston with his wife Ginger for 32+ years where they nurture trees, cattle, horses, and fish. He received Bachelor of Science degree in Mechanical Engineering from University of Alabama, and a Masters of Science degree in Theoretical and Applied Mechanics from West Virginia University. He is a Fellow in ASME and a long term member of the Society of Experimental Mechanics.

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Additional Readings

How the Barbarian Invasions Shaped the Modern World: The Vikings, Vandals, Huns, Mongols, Goths, and Tartars

who Razed the Old World and Formed the New - Thomas J. Craughwell, 2008The Metalsmiths – The Emergence of Man Time Life Books, 1974Out of the Fiery Furnace – The Impact of Metals on the History of Mankind – Robert Raymond, 1984A History of Metals in Colonial America – James Mulholland, 1981DE RE METALLICA – Georgius Agricola, translated by Hoover and Hoover, 1950The Internet – World Wide Web

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Historic Pathways to Steel : Forged and Cast(Out of the Fiery Furnace)

66

TerminologyMetal – a mineral or compound naturally occurring near the Earth surface and is sometimes described as a lattice of positive ions surrounded by a cloud of delocalized electrons. An element that readily loses electrons to form positive ions (cations) and forms metallic bonds between other metal atoms

Ore – a volume of rock containing components or minerals that have economic value

Alloy – combination of metals by melting (naturally or intended)

Refining – selective removal of metal from ore

Smelting – extracting metal from ore by heating

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What is a metal?

Opaque, lustrous element that is a good conductor of electricity and heat and a good reflector of light when polished.

Crystalline in the solid state

Solid at ambient temperatures– Except for Mercury

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Timeline of the Evolution of MaterialsI n d i a n I n s t i t u t e o f S c i e n c e, B a n g a l o r e, I N D I A

1,000,000 BC Man on Earth Stone Age Chalcolithic Age

8000 BC Native Copper, Native Gold, 6500 BC Smelting of copper from malachite, Arsenical bronze-an accidental alloy 4000 BC Silver

Bronze Age3000 BC Tin bronze 2900 BC First man-made iron object in the great pyramid of Giza 2700 BC Meteoritic iron in Egypt 2500 BC Lead in Indus Valley, India/Pakistan 1750 BC Tin 1500 BC Bronze by Shang dynasty in China Chinese princess discovers silk

Iron Age 1200 BC Smelting of iron by Hittites Bronze bells in China 1000-500 BC Wrought and quenched high-tin beta bronze vessels in South Indian megalithic and iron age sites 1000 700 BC Greeks and Indians quench and temper iron to improve the cutting characteristics 750 BC Mercury 500 BC Deepest old gold mine at Maski, India 500 BC Gold, Copper-gold, Gold–platinum alloys: Mayans, Aztecs, Incas in the Americas 500 BC Reference to diamond in Indian Sanskrit texts 300 BC Crucible steel in South India, later known as wootz200 BC Cast iron in China 100 BC Development of the Silk Road AD 400-420 Delhi Iron Pillar AD 1200 Zinc smelting at Zawar, India AD 1400 Blast furnace for iron making AD 1856 Bessemer Steel

http://met.iisc.ernet.in/~rangu/text.pdf

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http://library.thinkquest.org/08aug/01930/metalhistory.html

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Metal Discovery Rate

http://www.empirestateventures.com/base-history.shtml

1313

History of Metal DiscoveryBefore 1700 there were 12

metals in common use:

Gold Silver Copper Lead Mercury Iron Tin Platinum Antimony Bismuth Zinc Arsenic

12 Metals Discovered in 18th Century:

1735 Cobalt 1751 Nickel 1774 Manganese 1781 Molybdenum 1782 Tellurium 1783 Tungsten 1789 Uranium 1789 Zirconium 1791 Titanium 1794 Yttrium 1797 Berylium 1797 Chromium

Before 1805 all metals were reduced by either carbon or hydrogen

1414

42 METALS DISCOVERED IN 19th

CENTURY 1801 Niobium 1802 Tantalum 1803 Iridium, Palladium, Rhodium 1807 Potassium, Sodium 1808 Boron, Barium, Calcium, Magnesium, Strontium 1814 Cerium 1817 Lithium, Cadmium, Selenium 1823 Silicon 1827 Aluminum 1828 Thorium 1830 Vanadium 1839 Lanthanum

1843 Erbium, Terbium 1844 Ruthenium 1860 Cesium, Rubidium 1861 Thallium 1863 Indium 1875 Gallium 1878-1885 Holmium, Thulium, Scandium, Samarium, Gadalinium,Praseodynium, Neodynium, Dysprosium 1886 Germanium 1898 Polonium, Radium 1899 Actinium

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20 METALS DISCOVERED IN 20th

CENTURY 1901 Europium 1907 Lutetium 1917 Protactinium 1923 Hafnium 1924 Rhenium 1937 Technetium 1939 Francium 1945 Promethium 1940-61Transuranium elementsNeptunium Plutonium Curium Americum Berkelium

Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium

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Civilizations and Eras defined by their Material Technology

Stone AgeCopper AgeBronze AgeIron AgeDark AgesMedieval Ages

Modern Metal Age consists of many over-lapping Technical Ages after 1300

Age of SteelPetroleum Age Industrial AgeAge of FlightSpace Age -SputnikNuclear AgeComputer AgeComposite Material AgeNano Tech AgeGreen Age ?

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Metals of Antiquity

The metals upon which civilization was based. These seven metals were:

(1) Gold – 6000 BC (2) Copper – 4200 BC (3) Silver – 4000 BC (4) Lead – 3500 BC (5) Tin -1750 BC (6) Iron, smelted -1500 BC (7) Mercury – 750 BC

These metals were known to the Mesopotamians, Egyptians, Greeks and the Romans. Of the seven metals, five can be found in their native states, e.g., gold, silver, copper, iron (from meteors) and mercury.

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Ancient MetallurgyMetallurgy is the process of working metal into artifacts (tools and toys). Although small amounts of metals are found in relatively pure form, most must be extracted from more complex ores by removing the "impurities" (non-metal or other metal) from the combination ore. It is possible, of course, to pound on metal ores and chip off pieces, and a few very early "chipped stone" tools were in fact made of chipped ore. It is also possible to reshape raw ores slightly by pounding —depending upon the hardness of the alloy— and the result can sometimes be used as a tool. Metal ores processed in these ways have never been significant in human history, however. (For example, compared with chipped obsidian, chipped iron ore makes a far less usable tool.) Instead, usable metal tools involve heating and/or hammering the metal to work it into something usable.Over the centuries, smiths have used a range of techniques to process metal. This reference noted below begins with a discussion of copper and bronze, then of iron and steel, followed by brief discussions of lead, gold, and silver. The page then discusses metalworking methods.

http://weber.ucsd.edu/~dkjordan/arch/metallurgy.html

1919

History of Metals

Ancient Metals– Most metals naturally occur as minerals or

compounds– Ancient man used Gold, Silver or Copper because

they naturally existed in the form of metals– Copper ore reduction from copper sulfides

(covellite and malachite) began between 4000 and 3000 B.C.

– Two important ancient discoveries…..o Metal could be obtained from ores by heating

o Strength could be increased by hammering

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History of Metals

Bronze Age– Addition of tin to copper to form bronze

o ~ 88% Cu -12% Sn

– By 3000 B. C. ancient metallurgists had learned to intentionally mix ores of copper and tin to produce bronze, similar to today’s composition.

2121

Old World Metal Centers date to 9500

B.C. and were either sources

or manufacturing

sites.

Time-Life Books Emergence of ManThe Metalsmiths 1974

2222

King Tut funeral mask of beaten gold.

1343 B.C.

2323

Gold,Silver, and Electrum (natural alloy of

gold and silver)

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Multicolored CopperComponents of Bronze (Copper and Tin)

2525

Iron,a metal for the

Masses is second most

common metal.

Early sources were meteoric forms before

smelting mastered in 1200 B.C.

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TIMELINE

2727

Time-Life Books

Emergence of Man

The Metalsmiths

1974

Fifth Century B.C. Smiths forging

sickle at La Tene in Lower Austria

2828

Smiths forge at

La Tene in Lower Austria

was used 2500

years ago

2929

Celtic tools fromLa Tene were used

2500 years ago

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Technology Distribution Outward

Celtic Iron Age technology is commonly considered to begin around 1000 B.C. and lasting through 100 A.D. in Celtic Britain and ended with the arrival of Roman influence. http://www.wesleyjohnston.com/users/ireland/past/pre_norman_history/index.htm

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The Advent of Iron in Celtic Briton

The use of iron had amazing repercussions. First, it changed trade and fostered local independence. Trade was essential during the Bronze Age, for not every area was naturally endowed with the necessary ores to make bronze. Iron, on the other hand, was relatively cheap and available almost everywhere.

3232

And then…..more technology distribution ….and removal

Roman influence shaped the world until the “Barbarian” invasions changed it again, and again…

– Goths– Huns– Vandals– Viking– (Crusades – an out-vasion)– Mongols

In England the Viking Age began dramatically on January 6, 793 when Norsemen destroyed the abbey on Lindisfarne, a center of learning famous across the continent.

The Vikings who invaded western and eastern Europe were chiefly from Denmark, Norway and Sweden. They also settled the Faroe Islands, Iceland, Greenland and (briefly) North America.

http://www.hurstwic.org/history/articles/manufacturing/text/bog_iron.htm

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The Barbarian Invasion in

the Fifth and Sixth Centuries

33http://www.wwnorton.com/college/history/ralph/resource/barbaria.htm

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Mongol Conquests 13th CenturyThe Mongol invasions (also Turco-Mongol[1]) progressed throughout the 13th century, resulting in the vast Mongol Empire covering much of Asiaand Eastern Europe by 1300.

The Mongol Empire emerged in the course of the 13th century by a series of conquests and invasions throughout Central and Western Asia, reaching Eastern Europe by the 1240s. The speed and extent of territorial expansion parallels the Hunnic/Turkic conquests of the Migration period (the 6th century Turkic Khaganate).

The territorial gains of the Mongols persisted into the 15th century in Persia (Timurid dynasty) and in Russia (Tatar and Mongol raids), and into the 19th century in India (the Mughal Empire).

34http://en.wikipedia.org/wiki/Mongol_Conquests

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Mongol Beginnings

1162 or 1167 - Temujin was probably born in 1167, though Mongol tradition has it that he was born in 1162. Because much of his early life is not described, except in myth, reliable knowledge of his early life is very limited.

1185 – Temujin becomes a Khan and begins to unite the Mongols.

35http://www.indiana.edu/~iaunrc/mongol/Mongol%20History%20Timeline.doc

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Mongol Expansion

1237 – Ögödei has Batu Khan, Chinggis’ grandson, invade Russia. Over the next 5 years Batu conquers or destroys every city in Kievan Russia, occupies Georgia and Armenia, and invades Hungary, Poland, Bulgaria, and Croatia.

1241 – Ögödei dies. Mongol conquests are interrupted by a lack of strong central leadership.

1242 – Batu learns of Ögödei’s death and, partly because of his desire to influence who the next Khan would be, retreats from Europe to the Kipchak Steppe just north of the Caspian Sea. Western Europe is saved from a Mongol invasion.

1246 – Ögödei’s son Guyuk is pronounced Great Khan, but dies in 1248 without taking any new initiatives.

1251 – Batu engineers promotion of another Chinggisid descendant, the son of Tolui Mongke, to Great Khan. Some say his mother Sorghaghtani Beki, was the real power behind this.

36http://www.indiana.edu/~iaunrc/mongol/Mongol%20History%20Timeline.doc

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Mongol Endings

1252 – Mongke orders the invasions of Persia under Hulagu, and of southern China under Khubilai, his brothers.

1258 – Hulagu invades the Abbasid Caliphate and captures Bagdad.

1259 – Hulagu invades Syria

1260 – Mongke dies, Hulagu retreats to Iraq and Persia. The Mongol nation fails to decide on a successor as great Khan.

1279 – Kubilai completes the conquest of China. This point marks the greatest extent of the Mongol dominions.

1294 –The Mongol Empire is partitioned between the descendants of its last military leaders.

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http://www.indiana.edu/~iaunrc/mongol/Mongol%20History%20Timeline.doc

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Metals Melt

3939

Smelting is Extraction of Metal from Ore

Smelting is Extraction of Metal from Ore– Gold – already pure in nature and not extracted– Silver and Lead – 4000 B.C.– Tin – 3000 B.C.– Iron – 2700 B.C.

Requires a very hot fire– Technology borrowed from Ceramic/Pottery Crafts?– Charcoal for fuel– Air is blown into the fire

4040

Common IssuesThese seven metals: gold, silver, copper, lead, tin,

mercury and iron, and the alloys bronze and electrum were the starting point of metallurgy and even in this simple, historic account we find some of the basic problems of process metallurgy. The problems are:

The ores must be found, separated and sized before use. The ores must be reacted under a controlled temperature and gas atmosphere. The liquid metal must be collected and cast into a desired shape. The metal must be worked to achieve desired final properties and shape.

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Bronze Age WeaponsCasting Example

4242

Stamped CoinsRomans exported coin technology to Celtic Britton.Currency evolved from two basic innovations: the use of counters to assure that shipments arrived with the same goods that were shipped, and later with the use of silver ingots to represent stored value in the form of grain. Both of these developments had occurred by 2000 BC. Originally money was a form of receipting grain stored in temple granaries in ancient Egypt and Mesopotamia.

A Roman denarius, a standardized silver coin.

KINGS of Lydia Electrum coin. Early 6th century BC.

Gold 20-stater of Eucratides I ( reigned 171–145 BC),the largest gold coin ever minted in Antiquity

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Blacksmithing Coins

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Celtic Metal ArtLa Tène culture developed and flourished during the late Iron Age (from 450 BCE to the Roman conquest in the 1st century BCE) in eastern France, Switzerland, Austria, southwest Germany, the Czech Republic, Slovakia and Hungary.

Celtic art in the Middle Ages was practiced by the Celtic speaking people of Ireland and Britain in the 800 year period from the Roman withdrawal from Britain in the 5th century, to the establishment of Romanesque art in the 12th century

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NailsBronze nails, found in Egypt, have been dated 3400 BC.

In 1959 during excavation of the legionary fortress at Inchtuthil near Dunkeld, archaeologists uncovered a singularly remarkable haul of a single kind of Roman artifact from around 83 - 87 AD.

Located in a twelve foot deep pit below the beaten earth floor of the workshop - the Fabrica- was a remarkable hoard of nails, over eight hundred thousand in number, many in a remarkable state of preservation.

Pig iron was commonly imported into Roman Britain from iron producing areas of the empire- notably lower Germany- in small man hand-able billets.

An original 7" (180mm) long Roman nail found in Scotland

19th Century "Square" Nails

Replica of the hand made nails found on board the 'Mary Rose‘ -Tudor flag ship of Henry VIII built in 1509

Roman nail

found in Wales

4646

Viking Swords and UtensilsViking Age is the term denoting the years from about 700 to 1066 in European history.Viking society was based on agriculture and trade with other peoples.They ‘acquired’ technology from around the world.Metal crafts in Scandinavia were of a very high standard as regards the execution and craft skills.

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Revolutionary Furnace -1200 B.C. for Egyptian

copper smelting in Timna in the Negev

Desert

4848

Making Charcoal – recent technology method

Air flow in and out of the mud encased pile was controlled and limited for a slow oxygen starved burn to refine the wood into high

carbon charcoal.

4949

Laminating Iron without melting it – 1000 B.C.

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Laminating Iron without melting it – 1000 B.C.

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Wootz Steel as the Acme of Mankind’s Metallurgical Heritage

“Wootz was the first high-quality steel made anywhere in the world. According to reports of travelers to the East,

the Damascus swords were made by forging small cakes of steel that were manufactured in Southern India.

This steel was called wootz steel. It was more than a thousand years before steel as good

was made in the West.” -J. D. Verhoeven and A. Pendray, Muse, 1998

http://materials.iisc.ernet.in/~rangu/text.pdf

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Old and New Wootz Blades

http://www.buffaloriverforge.com/wootz/wootz.htmhttp://www.tms.org/pubs/journals/jom/9809/verhoeven-9809.html

5353

Afgan Silversmith using historic

technology today

5454

Iranian Coppersmith using historic technology

today

5555

Afgan Iron Making using

historic technology today for

plowshares

5656

Goldworking in ancient America

2000 years before Columbus

5757

Peru was a center of

metal working for Copper and Gold using hammered

sheets before the Aztecs

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From Copper to Iron

Tool and weapon makers learned to smelt copper long before iron became the dominant metal. Archeological evidence suggests that blacksmiths in the Middle East were smelting iron as early as 2500 B.C., though it would be more than a thousand years before iron became the dominant metal in the region.

To create higher qualities of iron, blacksmiths would require better furnaces. The technology gradually developed over the centuries. By the mid-1300s, taller furnaces and manually operated bellows allowed European furnaces to burn hot enough to not just soften iron, but actually melt it.

58http://science.howstuffworks.com/iron2.htm

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Medieval Smithing in Europe

6060

Georgius Agricola (1494-1555) Georg Bauer, better known by the Latin version of his name Georgius Agricola, is considered the founder of geology as a discipline.

He died in 1555, one year before the posthumous publication of De Re Metallica, his greatest work.

De Re Metallica (Latin for On the Nature of Metals (Minerals)) is a book cataloging the state of the art of mining, refining, and smelting metals, published in 1556.

The publication was delayed until the completion of the extensive and detailed woodcuts.

He describes the method of breaking hard rocks using fire-setting, which involved making a fire against a rock-face, and then quenching the rock with water to induce cracking by thermal shock.

In 1912, the first English translation of De Re Metallica was privately published in London by subscription. The translators were Herbert Hoover, a mining engineer (and later President of the United States), and his wife, Lou Henry Hoover, a geologist and Latinist.

http://archimedes.mpiwg-berlin.mpg.de/docuserver/images/archimedes/agric_remet_002_en/downloads/agric_remet_002_en.text.pdf

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German Smithing shown in 1500 A.D. woodcuts

from "De Re

Metallicus" by Agricola

6262

Smithing in 1500's, from a Flemish woodcut

6363

From "the Boy's Book of Trades", 1888

6464

Colonial Firearms and Artillery

6565

Colonial Kitchen Tools

and all Hardware for

the Home, Barn, and Equipment

6666

Colonial Smithing at Sturbridge Village

6767

Colonial Smithing at Williamsburg

6868

Colonial Smelting Furnace West VirginiaSmall, workable iron veins were discovered in many areas of West Virginia, and small furnaces were set up at these spots for smelting the ore and manufacturing bar iron for the pioneer blacksmiths.

Start of Operation: 1836 Blowout: 1847 Daily Tonnage: 4 tons Built By: Leonard Lamb

for Tassey & Bissel Stack: ? Blast: Cold Type: Charcoal

Located in Cooper's Rock State Forest just east of Morgantown, West Virginia

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Henry Clay Furnace Today

69

70

Henry Clay Furnace at

Coopers Rock WVA

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7171

Blast Furnace OperationFrom 1760 to the 1880s, charcoal fires heated to temperatures of up to 3,000 degrees with the aid of water- or steam-powered fans converted locally mined ore into iron in at least 25 locations. Most of the state's iron furnaces were found in the northeastern counties, where veins containing iron nodules are relatively common.

West Virginia's handful of furnace operators decided the effort of building furnaces and producing the charcoal and ore needed to make iron was a better bargain than paying the high cost of freighting bar iron or pig iron from existing furnaces east of the Blue Ridge.

West Virginia iron was used to make everything from stoves to nails and any number of tools, cooking utensils and household items that could be produced by pioneer blacksmiths.

West Virginia furnaces were also credited with producing the cannonballs used by Commodore Oliver H. Perry to defeat a squadron of six British vessels in the Battle of Lake Erie during the War of 1812.

7272

Tannehill Ironworks near Birminghambefore Civil War

Trees on the hillsides were felled to be made into charcoal that fed the huge blast furnaces. Roupes Creek and a mighty steam engine powered the blowing machines to heat the fires that melted ore to be formed into "pigs" of iron which, in turn, formed the tools of war for the Confederacy. At the height of production Tannehill could turn out 22 tons of iron a day. The iron was cast into ordnance, skillets, pots and ovens for the Southern army.

On March 31, 1865, it all ended in fire and destruction. Three companies of the Eighth Iowa Cavalry swept through the area as a part of Union General James H. Wilson's raid on Alabama war industry sites. Smoke rose from the charred remains of the ironworks and cabins that housed 500 workers. At day's end the furnaces were no longer operational, and the foundry, tannery, gristmill, and tax-in-kind warehouse were in ruins.

7373

Tannehill Museum

7474

Design Technology Change form Compression to Tension

With the Industrial Revolution in the 19th century, truss systems of wrought iron were developed for larger bridges, but cast iron did not have the tensile strength to support large loads. With the advent of steel, which has a high tensile strength, much larger bridges were built, many using the ideas of Gustave Eiffel.

The Eiffel Tower was built for the International Exhibition of Paris of 1889

The structure was built between 1887 and 1889 as the entrance arch for the Exposition Universelle, a World's Fair marking the centennial celebration of the French Revolution. Three hundred workers joined together 18,038 pieces of puddled iron (wrought iron is very pure form of structural iron which was the precursor to construction steel ), using two and a half million rivets, in a structural design by Maurice Koechlin.

Riveted lattice wind resistant design

The Forth Bridge is a cantilever railway bridge over the Firth of Forth in the east of Scotland opened in 1890

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Iron and Steel

Iron– Iron is a chemical element

Steel– Steel is formed by treating molten (melted) iron

with intense heat and mixing it (alloying) with carbon.

Wrought Iron– Wrought iron was made by first heating a mass of

iron ore and charcoal in a forge or furnace using a forced draft of air.

75http://42explore.com/ironsteel.htm

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Cast Iron and Steel MakingThe most commonly used iron ores are haematite (US: hematite), Fe2O3, and magnetite, Fe3O4.The common ores of iron are both iron oxides, and these can be reduced to iron by heating them with carbon in the form of coke. Coke is produced by heating coal in the absence of air.The molten iron from the bottom of the furnace can be used as cast iron.

76http://www.chemguide.co.uk/inorganic/extraction/iron.html

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Types of iron and steel

Cast Iron– Cast iron is very runny when it is molten and

doesn't shrink much when it solidifies. It is therefore ideal for making castings - hence its name. However, it is very impure, containing about 4% of carbon. This carbon makes it very hard, but also very brittle. If you hit it hard, it tends to shatter rather than bend or dent.


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Wrought iron– If all the carbon is removed from the iron to give

high purity iron, it is known as wrought iron. Wrought iron is quite soft and easily worked and has little structural strength. It was once used to make decorative gates and railings, but these days mild steel is normally used instead.


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Mild steel– Mild steel is iron containing up to about 0.25% of

carbon. The presence of the carbon makes the steel stronger and harder than pure iron. The higher the percentage of carbon, the harder the steel becomes.

– Mild steel is used for lots of things - nails, wire, car bodies, ship building, girders and bridges amongst others.


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High carbon steel– High carbon steel contains up to about 1.5% of

carbon. The presence of the extra carbon makes it very hard, but it also makes it more brittle. High carbon steel is used for cutting tools and masonry nails (nails designed to be driven into concrete blocks or brickwork without bending). You have to be careful with high carbon steel because it tends to fracture rather than bend if you mistreat it.


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How Iron and Steel Work

This lump of iron ore is the starting point of everything from precision surgical equipment to reinforced skyscrapers. Before many ancient civilizations began to transition from their bronze age to an iron age, some toolmakers were already creating iron implements from a cosmic source: meteorites. Called 'black copper" by the Egyptians, meteoric iron isn't the sort of substance one finds in huge, consolidated locations. Rather, craftsmen found bits and pieces of it spread across great distances.

81

http://science.howstuffworks.com/iron2.htm

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As such, this heavenly metal was mostly used in jewelry and ornamentation. While blacksmiths occasionally used meteoric iron to craft swords, these prized weapons were usually relegated to men of great power, such as the seventh century Caliphs, whose blades were said to have been forged from the same material as the Holy Black Stone of Mecca [source: Rickard].

The majority of Earth's iron, however, exists in iron ore. Mined right out of the ground, raw ore is mix of ore proper and loose earth called gangue. The ore proper can usually be separated by crushing the raw ore and simply washing away the lighter soil. Breaking down the ore proper is more difficult, however, as it is a chemical compound of carbonates, hydrates, oxides, silicates, sulfides and various impurities.


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To get to the bits of iron in the ore, you have to smelt it out. Smelting involves heating up ore until the metal becomes spongy and the chemical compounds in the ore begin to break down. Most important, it releases oxygen from the iron ore, which makes up a high percentage of common iron ores.

The most primitive facility used to smelt iron is a bloomery. There, a blacksmith burns charcoal with iron ore and a good supply of oxygen (provided by a bellows or blower). Charcoal is essentially pure carbon. The carbon combines with oxygen to create carbon dioxide and carbon monoxide (releasing lots of heat in the process). Carbon and carbon monoxide combine with the oxygen in the iron ore and carry it away, leaving iron metal.


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How Iron and Steel WorkIn a bloomery, the fire doesn't get hot enough to melt the iron completely. Instead, the iron heats up into a spongy mass containing iron and silicates from the ore. Heating and hammering this mass (called the bloom) forces impurities out and mixes the glassy silicates into the iron metal to create wrought iron.

Wrought iron is hardy and easy to work, making it perfect for creating tools.

Tool and weapon makers learned to smelt copper long before iron became the dominant metal. Archeological evidence suggests that blacksmiths in the Middle East were smelting iron as early as 2500 B.C., though it would be more than a thousand years before iron became the dominant metal in the region.

To create higher qualities of iron, blacksmiths would require better furnaces. The technology gradually developed over the centuries. By the mid-1300s, taller furnaces and manually operated bellows allowed European furnaces to burn hot enough to not just soften iron, but actually melt it.


85

Creating Steel

Steel is iron that has most of the impurities removed. Steel also has a consistent concentration of carbon throughout (0.5 to 1.5 percent). Impurities like silica, phosphorous and sulfur weaken steel tremendously, so they must be eliminated. The advantage of steel over iron is greatly improved strength.

The open-hearth furnace is one way to create steel from pig iron. The pig iron, limestone and iron ore go into an open-hearth furnace. It is heated to about 1,600 degrees F (871 degrees C). The limestone and ore form a slag that floats on the surface. Impurities, including carbon, are oxidized and float out of the iron into the slag. When the carbon content is right, you have carbon steel.

85


86

Creating Steel

Another way to create steel from pig iron is the Bessemer process, which involves the oxidation of the impurities in the pig iron by blowing air through the molten iron in a Bessemer converter. The heat of oxidation raises the temperature and keeps the iron molten. As the air passes through the molten pig iron, impurities unite with the oxygen to form oxides. Carbon monoxide burns off and the other impurities form slag.

However, most modern steel plants use what's called a basic oxygen furnace to create steel. The advantage is speed, as the process is roughly 10 times faster than the open-hearth furnace. In these furnaces, high-purity oxygen blows through the molten pig iron, lowering carbon, silicon, manganese and phosphorous levels. The addition of chemical cleaning agents called fluxeshelp to reduce the sulfur and phosphorous levels.


87

Creating Steel Alloy

A variety of metals might be alloyed with the steel at this point to create different properties. For example, the addition of 10 to 30 percent chromium creates stainless steel, which is very resistant to rust. The addition of chromium and molybdenum creates chrome-moly steel, which is strong and light.

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88

Creating Steel

When you think about it, there are two accidents of nature that have made it much easier for human technology to advance and flourish.

– One is the huge availability of iron ore.

– The second is the accessibility of vast quantities of oil and coal to power the production of iron.

Without iron and energy, we probably would not have gotten nearly as far as we have today.

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8989

Steel Making begins in Birmingham 1897

9090

Sloss Furnaces fueled by Coalin Birmingham,

Alabama

www.Sloss Furnaces.com

9191

Sloss Furnaces once fueled by Coal are silent

today

9292

Vulcan on Red Mountain in

Birmingham

http://en.wikipedia.org/wiki/Vulcan_statue

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Technologies Fade AwayBlacksmith– Essential skills for 12,000 years– Industrial Age made the skill ‘obsolete’ around 1930– Smiths migrated into towns and were absorbed by other

industries such as large industrial forge shops and auto repair garages

Metallurgy and Materials– Essential skills for 500 years– Tomorrow? Will Green Age and composite materials render

metallurgy obsolete?

Will natural and/or man-made disaster erase today’s centers of learning and manufacture?

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Blacksmithing Survives and Thriveswww.habairon.org

http://www.habairon.org/

Thanks!

Richard Boswell

[email protected]

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History of Metals

Iron Smelting– Iron production began in Anatolia in 2000 B.C.– Iron production well established by 1000 B.C.– Widely available sources of charcoal (from wood)

and iron ore caused iron production to spread widely (in China) by 500 B.C.

– Intentional reduction of iron oxide ore using charcoal (from wood) was widespread in Egypt by 1500 B. C.

– Egyptians were tempering iron by 900 B.C.

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History of Metals

Iron Smelting– Requires higher temperatures than for lead.– Involves oxide reduction using carbon in the form

of charcoal or coke to reduce iron oxide to iron, forming carbon monoxide and carbon dioxide.

o Carbon serves two purposes• Reduction agent• Fuel

o Early furnaces used either natural draft air or forced air.

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History of Metals

Iron smelting (hearth processes)– Early iron process were variations of “closed-pit”

or “hearth” furnaces:– Used charcoal embedded in iron ore to reduce ore

to iron.– Incorporated various air blowing techniques to

make a “hot” fire.o Natural draft and forced draft.

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Smelting of Metals

Iron Smelting (hearth processes)– Early product of smelting was “wrought” iron.

o Soft, spongy, ductile, low carbon, malleable.

– If carbon absorbed, the iron was somewhat harder than low carbon wrought iron.

– Quenching to form a hard iron discovered early.

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Smelting of Metals

Iron smelting (hearth processes)– In all furnaces iron oxide was reduced to iron.– Carbon monoxide and carbon dioxide formed.– Product was “sponge” iron.

o High in carbon, silicon, phosphorous, manganese.

– If sponge iron kept in contact with the charcoal, it would absorb carbon

o Good or bad?

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Smelting of Metals

Iron Smelting– Modern basic reduced iron is termed “pig” iron.

o Contains significant quantities of carbon, sulfur and phosphorus.

• Carbon = 3.5% - 4.25%• Silicon = 1.25% - 1.25%• Manganese = 0.90% - 2.50%• Sulfur = 0.04% - 0.04%• Iron = Balance

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Iron

Pig iron vs. wrought iron– Wrought iron is ductile– Pig iron is brittle

o What element causes the difference?

Metallurgy for the Non Metallurgist Lesson 1 A History of ... Sept 2013 Long Journey of Smiths.pdf · The Long Journey of Blacksmiths and Steel Making (a tapestry of historical metal

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