History of Metals 2011 - HABA Houston Area Blacksmith`s Association

Transcription

September 29, 2010
The Long Journey of Blacksmiths
and Steel Making
(a tapestry of historical metal development)
Metallurgy for the
Non Metallurgist
Lesson 1
A History of Metals
September 28, 2011
Richard Boswell, P.E.
Mechanical Engineer
Blacksmith
1
Our Reference
Document for this
class
ASM Course 0135
Lesson 1
2
ASM Metals: A History
1
September 29, 2010
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, 2008
The Metalsmiths – The Emergence of Man Time Life Books, 1974
Out of the Fiery Furnace – The Impact of Metals on the History of
Mankind – Robert Raymond, 1984
A History of Metals in Colonial America – James Mulholland, 1981
DE RE METALLICA – Georgius Agricola, translated by Hoover and
Hoover, 1950
The Internet – World Wide Web : see footnote links
3
Historic Pathways to Steel : Forged and Cast
(Out of the Fiery Furnace)
4
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September 29, 2010
Terminology

Metal – 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
5
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 Materials
Indian
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 Age

3000 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 wootz

200 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/frontpage.pdf and http://met.iisc.ernet.in/~rangu/text.pdf
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The Big Picture
http://library.thinkquest.org/08aug/01930/metalhistory.html
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10
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Metal Discovery Rate
http://www.empirestateventures.com/base-history.shtml
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History of Metal Discovery
Before 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:

Before 1805 all metals were reduced by either carbon or hydrogen
1735 Cobalt
1751 Nickel
1774 Manganese
1781 Molybdenum
1782 Tellurium
1783 Tungsten
1789 Uranium
1789 Zirconium
1791 Titanium
1794 Yttrium
1797 Berylium
1797 Chromium
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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
elements
Neptunium
Plutonium
Curium
Americum
Berkelium

Californium
Einsteinium
Fermium
Mendelevium
Nobelium
Lawrencium
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September 29, 2010
Civilizations and Eras defined by their
Material Technology

Stone Age
Copper Age
Bronze Age
Iron Age
Dark Ages
Medieval Ages
Modern Metal
Age consists of
many overlapping
Technical Ages
after 1300

Age of Steel
Petroleum Age
Industrial Age
Age of Flight
Space Age -Sputnik
Nuclear Age
Computer Age
Composite Material Age
Nano Tech Age
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Green Age ?
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 Metallurgy

Metallurgy 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
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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.
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Old World
Metal Centers
date to 9500
B.C. and were
either sources
or
manufacturing
sites.
Time-Life Books Emergence of Man
The Metalsmiths 1974
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King Tut
funeral
mask of
beaten
gold.
1343 B.C.
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Gold,
Silver, and
Electrum
(natural
alloy of
gold and
silver)
22
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Multicolored Copper
Components of Bronze (Copper and Tin)
23
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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T
I
M
E
L
I
N
E
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Time-Life
Books
Emergence of
Man
The
Metalsmiths
1974
Fifth Century B.C.
Smiths forging
sickle at La Tene
in Lower Austria
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Smiths
forge at
La Tene in
Lower
Austria
was used
2500
years ago
27
Celtic tools from
La 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
http://www.wesleyjohnston.com/users/ireland/past/pre_norman_history/index.htm
influence.
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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.
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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
http://www.wwnorton.com/college/history/ralph/resource/barbaria.htm
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Mongol Conquests 13th Century

The Mongol invasions (also Turco-Mongol[1])
progressed throughout the 13th century, resulting
in the vast Mongol Empire covering much of Asia
and 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).
http://en.wikipedia.org/wiki/Mongol_Conquests
33
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.
http://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.
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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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Metals Melt
37
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
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Common Issues
These 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 Weapons
Casting Example
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Stamped Coins

Romans 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 Art

La 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
43

Bronze 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.
Nails
Roman nail

Pig iron was commonly
imported into Roman Britain
from iron producing areas
of the empire- notably lower
Germany- in small man
hand-able billets.
found in Wales
19th Century "Square" Nails
An original 7" (180mm) long Roman nail found in Scotland
Replica of the hand made nails found on board the 'Mary Rose‘ Tudor flag ship of Henry VIII built in 1509
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Viking Swords and Utensils

Viking 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.
45
Revolutionary Furnace
-1200 B.C. for Egyptian
copper smelting in
Timna in the Negev
Desert
46
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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.
47
Laminating Iron without melting it
– 1000 B.C.
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Laminating Iron without melting it
– 1000 B.C.
49
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://met.iisc.ernet.in/~rangu/frontpage.pdf and http://met.iisc.ernet.in/~rangu/text.pdf
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September 29, 2010
Old and New Wootz Blades
http://www.tms.org/pubs/journals/jom/9809/verhoeven-9809.html
http://www.buffaloriverforge.com/wootz/wootz.htm
51
Afgan Silversmith
using historic
technology today
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Iranian
Coppersmith
using historic
technology
today
53
Afgan Iron
Making
using
historic
technology
today for
plowshares
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September 29, 2010
Goldworking in
ancient America
2000 years
before Columbus
55
Peru was a
center of
metal
working for
Copper and
Gold using
hammered
sheets before
the Aztecs
56
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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.
http://science.howstuffworks.com/iron2.htm
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Medieval Smithing in Europe
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September 29, 2010
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
59
German
Smithing
shown in
1500 A.D.
woodcuts
from
"De Re
Metallicus"
by Agricola
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Smithing in 1500's, from a Flemish woodcut
61
From "the Boy's Book
of Trades", 1888
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Colonial Firearms and Artillery
63
Colonial
Kitchen Tools
and all
Hardware for
the Home,
Barn, and
Equipment
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Colonial Smithing at Sturbridge Village
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Colonial Smithing at Williamsburg
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September 29, 2010
Colonial Smelting Furnace West Virginia
Small, 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
67
Henry Clay Furnace
Today
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September 29, 2010
Henry Clay
Furnace at
Coopers Rock
WVA
69
Blast Furnace Operation

From 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.
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September 29, 2010
Tannehill Ironworks near Birmingham
before 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.
71
Tannehill Museum
72
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September 29, 2010
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
73
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.
http://42explore.com/ironsteel.htm
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September 29, 2010
Cast Iron and Steel Making

The 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.
http://www.chemguide.co.uk/inorganic/extraction/iron.html
75
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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September 29, 2010

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.
77

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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September 29, 2010

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.
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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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In 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.
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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.
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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 fluxes
help to reduce the sulfur and phosphorous levels.
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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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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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Steel Making begins in Birmingham 1897
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Sloss Furnaces
fueled by Coal
in Birmingham,
Alabama
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Sloss Furnaces
once fueled by
Coal are silent
today
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Vulcan
on Red Mountain in
Birmingham
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Technologies Fade Away

Blacksmith
– 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 Thrives
www.habairon.org
http://www.habairon.org/
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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
o
Carbon serves two purposes
• Reduction agent
• Fuel
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?
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