Metallurgical Heritage of India & Monte Carlo simulation of grain growth

Metallurgical Heritage of IndiaOverview of the presentationMetallurgical Heritage of India1. Wootz steel2. Chola bronzes3. Emperor of the plains4. The rustless wonder5. Black and silver magicWootz steel/Damascus sword

Wootz steelWootz is the anglicized version of ukku in the languages of the states of Karnataka, and Andhra Pradesh, a term denoting steel. Literary accounts suggest that the steel from the southern part of the Indian subcontinent was exported to Europe, China, the Arab world and the Middle East. Wootz steelThough an ancient material, wootz steel also fulfills the description of an advanced material, since it is an ultra-high carbon steel exhibiting properties such as superplasticity and high impact hardness and held sway over a millennium in three continents- a feat unlikely to be surpassed by advanced materials of the current era.

Wootz steelWootz deserves a place in the annals of western science due to the stimulus provided by the study of this material in the 18th and 19th centuries to modern metallurgical advances, not only in the metallurgy of iron and steel, but also to the development of physical metallurgy in general and metallography in particular. Indian wootz ingots are believed to have been used to forge Oriental Damascus swords which were reputed to cut even gauze kerchiefs and were found to be of a very high carbon content of 1.5-2.0%.

Wootz steelIn India till the 19th century swords and daggers of wootz steel were made at centres including Lahore, Amritsar, Agra, Jaipur, Gwalior, Tanjore, Mysore, Golconda etc. although none of these centres survive today. The art of making Wootz steel was lost in India due to advent of fire arms, and due to depletion of iron ore deposits which had trace elements of vanadium which was primarily responsible for the fine carbides present in the wootz steel.

Wootz steel

Wootz steel

Wootz steelWestern interest in Wootz steel is very high since the medieval times.In the last 20 years Sherby and Verhoeven have worked on Wootz steel, and the latter has recreated the steel with modern equipment.Chola bronzes

Chola bronzesChola bronze icons from Tamil Nadu (c. 9th-13th century) in southern India, such as the Nataraja often described as cosmic dance of the Hindu god Siva, rank amongst the finest of religious expressions with often revelationary implications for our present day understanding of art, music, dance, poetry, science, history, society, psychology and philosophy.

Lost Wax technique

Chola period bronzes were created using the lost wax processWax made from beehives and kungilum (a type of camphor) are mixed with a little oil and kneaded well. The figure is sculpted from this mixture fashioning all the minute details. This is the wax model original.The entire figure is then coated with clay made from special clay available on the banks of river Kaveri until the mould is of a necessary thickness. Then the whole assembly is dried and fired in an oven with cow-dung cakes. The wax model melts and flows out, leaving behind the mould of the shape of the wax sculpted.

Chola bronzesThe metal alloy of bronze is melted and poured into the empty clay-mould. This particular bronze alloy is known as Pancha Loham. When the metal has filled all crevices and has settled and hardened and cooled, the mould is broken off. The bronze figure thus obtained is then cleaned, finer details are added, blemishes are removed, smoothened, and polished well. Hence each bronze icon is unique and the mould cannot be used to create copies.

Chola bronzes

Chola bronzes

Chola bronzes

Identify

Malik-e-maidan

'Malik-E-Maidan' (lord of the battlefield) is the largest medieval cannon in the world, fourteen feet long and weighing about 55 tons. It was cast at Ahmednagar from bell metal (70% Cu and 30% Tin) and shifted to Bijapur in 1632, after wreaking havoc in 1565 at the Battle of Talikota.Muhammad-bin-Hasan Rumi, a Turkish officer in the service of the king of Ahmednagar, cast this gun in 1549, as can be seen from an inscription on the gun.

Malik-e-maidan

Malik-e-maidanIn 1686 Aurangzeb has also recorded an inscription on the gun saying that he subdued the Malik-e-Maidan. When the fort of Parnadah where this gun was installed, fell in to hands of Bijapur, General Murari Pandit brought the gun to Bijapur as a trophy of war and set it up on the present bastion. It was set up here with the help of 10 elephants, 400 oxen and hundreds of soldiers. It weighs 55 tons, is 4.5 metres long and 1.5 metres in diameter. To avoid going deaf, the gunner had to submerge his head in water before firing. Legend has it that if you touch the gun and make a wish, it will come true!

Malik-e-maidan

Which cannon ??

Jaivana cannon: World's biggest ever wheeled cannonThe Jaivana cannon is the world's biggest wheeled cannon ever made. It is located at the Jaigarh Fort, Jaipur.It was cast in 1720, during the reign of Maharaja Sawai Jai Singh II of Jaipur.Jaivan rests on a high 4 wheeled carriage. The front wheels are 2.74 m in diameter and the rear wheels are 1.37 m in diameter. The barrel is 6.147 m long and weighs 50 tons. It rests on a 7.3 m long shaft. The tip of the barrel is 711 mm in dia., while the rear of the barrel is 906 mm dia. An 776 mm long elevating screw was used for raising and lowering the barrel.Reportedly, it took four elephants to swivel it around on its axis!

Jaivana cannon Never used in battle, the Maharaja Jai Singh reportedly test-fired it once in 1720.The cannon ball is said to have landed at Chaksu about 40 km to the south. The impact formed a pond at the spot.Cannons always had a water tank beside them, for the gunner to jump into to avoid the massive shock wave. Jaivana's gunner is said to have died on the spot on firing the cannon, before he could jump into water. Eight people and one elephant were also reportedly killed by the shock wave and many houses collapsed in Jaipur.Wasn't it a feat to transport this cannon to the top of the hill where it is placed?

Jaivana cannon

The Rustless wonderThe Iron Pillar from Delhi7.3 m tall, with one meter below the ground; the diameter is 48 centimeters at the foot, tapering to 29 cm at the top, just below the base of the wonderfully crafted capital; it weighs approximately 6.5 tones, and was manufactured by forged welding.The Iron Pillar dates from Gupta King, who ruled from 375 - 413 ADInscription on the rust resilient Iron Pillar from Delhi

The Delhi Iron PillarMetallurgists at Kanpur IIT have discovered that a thin layer of "misawite", a compound of iron, oxygen and hydrogen, has protected the cast iron pillar from rust. The protective film took form within three years after erection of the pillar and has been growing ever so slowly since then. After 1,600 years, the film has grown just one-twentieth of a millimeter thick, according to R. Balasubramaniam of the IIT.

The Delhi Iron PillarIn a report published in the journal Current Science Balasubramanian says, the protective film was formed catalytically by the presence of high amounts of phosphorous in the ironas much as one per cent against less than 0.05 per cent in today's iron. The high phosphorous content is a result of the unique iron-making process practiced by ancient Indians, who reduced iron ore into steel in one step by mixing it with charcoal. Modern blast furnaces, on the other hand, use limestone in place of charcoal yielding molten slag and pig iron that is later converted into steel. In the modern process most phosphorous is carried away by the slag.

The Delhi Iron Pillar

Which art work is this? Which fort?

Bidri Ware - A Magic in Black and Silver

Bidriware

Bidriware

Bidriware

Bidriware

Bidriware

Bidriware derives its name from Bidar. The 500 year old art is Persian in origin, but bidriware is purely Indian innovation. This art of engraving and inlaying is handed down by generations and is exclusive to Bidar .Bidriware is manufactured from an alloy of copper and zinc (in the ratio 1:16) by casting. The zinc content gives the alloy a deep black color. First, a mould is formed from soil made malleable by the addition of castor oil and resin. The molten metal is then poured into it to obtain a cast piece which is later smoothened by filing. BidriwareThe casting is now coated with a strong solution of copper sulphate to obtain a temporary black coating over which designs are etched freehand with the help of a metal stylus.This is then secured in a vise and the craftsman uses small chisels to engrave the design over the freehand etching. Fine wire or flattened strips of pure silver are then carefully hemmered into these grooves.The article then is filed, buffed and smoothed to get rid of the temporary black coating. This results in rendering the silver inlay hardly distinguishable from the gleaming metallic surface which is now all silvery white.BidriwareThe bidriware is now ready for the final blackening (or oxidizing) process. Here, a special variety of soil which is available only in the unlit portions of the Bidar fort is used. It is mixed with ammonium chloride and water to produce a paste which is then rubbed onto a heated bidri surface. The paste selectively darkens the body while it has no effect on the silver inlay.The paste is then rinsed off to reveal a shiny silver design resplendent against the black surface. As a finishing touch, oil is applied to the finished product to deepen the matt coating. The finished product appears black with brilliant silver inlay.

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