IRON SMITHY - craft -1
Post 107 ⇒ by Gautam Shah ➔
.
Since prehistoric times, nearly every region of the world and every
culture had some knowledge about iron. It was perhaps not sufficient
enough to explore the very abundant resource material. Bronze was
easier to extract and work, but Iron was tougher than bronze. It was less
toxic for food and water storage, except for rusting. Pure iron as meteorite
nodule is soft but unavailable in sufficient quantity. First lesson of iron-smithy was the realization that smelted Iron (with its impurities, chiefly of
Carbon -automatically included during smelting) is a very hard and
durable material. First Iron utilities were of Cast Iron varieties.
 |
| Iron Bloom |
Lack of copper, and the abundance of iron everywhere encouraged
developments in iron working. Large furnaces produced vast quantity of
iron that was not processed further, but was shaped into various forms
(vessels and solids) through casting and moulding. The next Iron smithy
craft was forming sharp edged tools for home, agriculture, hunting and
warfare. This was done by forging a shape and annealing-hardening
treatments. The treatments and reheating showed how to adjust carbon
content as well as other impurities. It is believed that by 5th C. BC, bronze
was replaced by iron as the material for utensils forming and weapons
making.
Iron making must have started in India, earlier then 1800 BC, as Rig-Veda
mentions Ayas (metal) or Shyam or Krsna Ayas (black metal). A
description like ‘for as a ploughshare that has got hot during the day when
thrown into the water splashes, hisses and smokes in volumes’ shows use
of quenching processes.
First crucible-based steels were developed in India, around 300 BC. In
this process iron was mixed with glass, as the mixture cooled glass would
bond with impurities, and float to the surface as scum. The porous walls of
the crucibles added the carbon. This steel was exported throughout the
Middle East, where it was known as Faulad (Persian). Faulad or wootz
steel (in Europe) has a Kannada term(Language of Indian region of
Karnataka) for it, ukku.
 |
| Water pattern on Damascus steel swords These images are of 1800 AD production |
Faulad was processed further to produce Damascus steel. Swords and
other sharp cutting edge tools made from Damascus steel had distinctive
patterns of banding and mottling reminiscent of flowing water. In India
though for a long time after 600 BC, cast-iron was used for making spikes,
knives, daggers, arrowheads, bowls, spoons, saucepans, axes, chisels,
tongs, door fittings etc. India had mastered the craft of casting very large
sized pillars.
 |
| Iron Pillar Delhi India |
Chinese were able to melt the Iron and cast it into desired forms. This
method was less labourious than individually forging each piece of iron
from a bloom. But most remarkable point was that China’s iron smelters
achieved a temperature of 1130 °C, hot enough to be considered a blast
furnace. The devised very efficient bellows of leather to deliver a
continuous stream of air into a furnace. Chinese smiths had also mastered
the technique of melting wrought iron and cast iron together to produce
a material of intermediate carbon content that is steel. The process was
called ‘harmonizing the hard and the soft’. This was to be the basis of
casting of Iron statuettes.
 |
| Chinese poodle and Blast furnaces |
The furnaces and bellows as used in Roman time Europe worked at
1100° -1200° C, so Pure Iron’s melting point temperature of 1540°C was
difficult. Iron at this temperature did become soft but not liquid. It was a
solid state conversion requiring chemical reduction of the ore. Ore was
placed in a pit and mixed with hot charcoal fire. After a sustained
temperature of 1100°-1200°C, the slag fell to the bottom leaving the
spongy mass of iron called Bloom. The bloom while hot, was pounded,
into a denser mass called wrought iron.
In later periods, both the processes, the cementation and the crucible
process, were practised. ‘In a cementation process wrought iron was
heated with charcoal (to add carbon) without exposure to air, whereas In
a crucible process wrought iron bars were melted in crucibles with
charcoal.’ For wootz steel was made by a different type of blast furnace.
Here a charge of Iron ore and a charcoal material was added in the
crucible. It was held at high temperature for long time, for the bloom to
absorb enough carbon and reduce the melting point of the iron. Cast
buttons or disks were reheated in the direct flame to a temperature just
below their melting point. The buttons were then forged together by
pounding.
Roman steels provided Hooks, harness rings, tires, chisels, adzes, saws
and shovels, but not the damask swords. Roman artefacts include few
items of case-hardened sharp edges, but architectural craft uses were
rare.
Roman-Greek attitude to Metal making is exemplified by Aristotle.
He noticed there were large amount of unattractive metals in the
ground such as lead, iron, and Tin. He thought every thing grows
(develops) to perfection, and so these metals in stages can grow
into Gold. Ancient miners blocked the mines to let Earth grow the
metals in her womb. The ancient Greeks believed that Iron rusted
because elements like water, fire, air left Iron leaving the Earth-rust
behind.
Greek metal smiths worshipped Hephaestus. Greeks placed small
dwarf-like statues of Hephaestus near their hearths. He used the fire of the
forge as a creative force, and had twenty bellows that worked at his
bidding. He designed Hermes' winged helmet and sandals, the Aegis
breastplate, Aphrodite's famed girdle, Agamemnon's staff of office,
Achilles' armour, Heracles' bronze clappers, Helios' chariot, the shoulder
of Pelops, and Eros' bow and arrows. He was a crippled god of fire,
metalworking, and craft, with the tools of a smithy hammer, tongs and
anvil. His crippled, lamed and ugly appearance is believed due to effect
of arsenic poisoning, a common problem with all metal smiths. His sacred
animals were donkey, dog and crane. He was husband of adulterous
Aphrodite (Greek goddess of love, beauty, pleasure, and procreation and
Roman equivalent of Venus).
Hephaestus was Roman equivalent of Vulcanus. Vulcanus (Vulcan) was
feared for his destructive potential and associated with the volcanic power
of the earth, but Hephaestus was gentle. Another mythical figure of
Scandinavia was metal working Thor. His hammer was unbreakable,
struck its target without fail, and no matter how hard and how far he threw
it, always came back to him.
 |
| Forge of the Vulcan |
 |
| hephaestus-aphrodite-forge |
 |
| Roman God of Fire Forge and Anvil |
.
No comments:
Post a Comment