Bronze was the hardest material known to man until iron was found around 1500 BC. At that time, nobody knew that iron would change almost every aspect of human life. This “magical” metal was first discovered by the residents of the Hittities, an area now known as modern Turkey. The iron ore found there is believed to have come from meteorites.
One big problem in using iron was its high melting point. Primitive furnaces could not raise the temperature to the melting point of iron. People heated the iron ore as far as they could and then pounded it with hammers to squeeze out carbon and other impurities. Even though iron was more abundant than copper and tin, it was more difficult to work with. Widespread use of iron had to wait for the invention of the charcoal furnace in 1500 B.C.
In its pure form, iron is actually less hard than bronze. When iron is heated in a charcoal furnace, the carbon in charcoal bonds with iron to form the alloy we call steel. Steel is one of the strongest materials on earth. By 1000 BC, man had learnt to make even stronger steel by adding in small amounts of other metals such as manganese, chromium, vanadium and tungsten. The art of steelmaking developed rapidly. As an example, an iron pillar in Delhi, India, dating back to 400 AD, still stands today free from rust and other damage.
The Iron Age started just 3,500 years ago!
Iron and steel made old weapons stronger. During the late Iron Age, people started smelting chain armor. New weapons such as long swords now became possible. Over time, steel swords and bows gave way to steel rifles and cannons. The use of artillery in war created the need for stronger armor.
The ready supply of iron and steel helped prevent an economic crisis from the shortage of copper and tin to make bronze. Iron and steel replace bronze as the building blocks for human civilization. In particular, transportation vehicles such as ships and railroads changed our lives forever.
Aitcheson, Leslie. A History of Metals. Volumes 1 & 2. 1960. Interscience, New York, USA.
Cramb, Alan W. A Short History of Metals. Published online, <http://neon.mems.cmu.edu/cramb/Processing/history.html> accessed on 11-March-2009.
Habashi, Fathi. Principles of Extractive Metallurgy. Volume 1, Chapter 1. 1969. Gordon and Breach, Science Publishers, Inc., New York, USA.
Hartmen, Paul V. Stone Age, Bronze Age and Iron Age. An online history essay, <http://www.naciente.com/essay88.htm> accessed on 11-March-2009.
Cramer, Clayton, E. What caused the Iron Age. 1995 published at <http://www.claytoncramer.com/unpublished/Iron2.pdf> accessed on 28-Mar-2009.
Hynes, Margaret. The Best Book of Early People,2003, Kingfisher Publications, USA.
Wertime, Theodore A. and Mulhy, James D. (eds). The Coming of the Age of Iron, 1980, Yale University Press, USA.