The newsLINK Group - A Primer on Iron and Iron Alloys

Editorial Library Category: Mining Topics: Primer, Iron, Iron Alloys Title: A Primer on Iron and Iron Alloys Author: newsLINK Staff Synopsis: Iron has been a useful metal for five or six thousand years, which is when the Egyptians began working with it. Historians believe they got their iron from meteorites. Production was a closely guarded secret because it was the best metal available at the time for making weapons and tools, but historians have also found what they think are sites where iron mining and smelting took place in what is now Turkey. Editorial: A Primer on Iron and Iron Alloys 4064 South Highland Drive, Millcreek, Utah 84124 │ thenewslinkgroup.com │ (v) 801.676.9722 │ (tf) 855.747.4003 │ (f) 801.742.5803 Editorial Library | © The newsLINK Group LLC 1 Iron has been a useful metal for five or six thousand years, which is when the Egyptians began working with it. Historians believe they got their iron from meteorites. Production was a closely guarded secret because it was the best metal available at the time for making weapons and tools, but historians have also found what they think are sites where iron mining and smelting took place in what is now Turkey. The people who did the iron mining and smelting in Turkey were enemies of Egypt named Hittites. (The Hittites also lived in northern Syria.) The Hittites were known for their long hair and their use of strategy and tactical skill in battle. Ramses II initially despised them, thinking they were effeminate, but he learned to respect them in battle, eventually made peace with them, and chose to marry a Hittite woman. The existence of those ancient mining and smelting sites are revealing. The secret of working with iron could not be kept from Egypt’s enemies for long, if only because the basic techniques were simple ones. However, there was still a great deal to learn about iron. One disadvantage of iron was that its quality varied. Where it was mined and how the iron was extracted both made a difference when making tools or weapons from it. Historians have found additional early evidence of cultures that discovered and used iron in places such as China, India, Japan, and the Middle East. In particular, the Japanese were able to create centuries-old heirloom steel swords. European methods lagged. The Europeans did not know how to heat iron to the melting point. What they did instead was to build clay-lined ovens and use the ovens to burn wood and iron ore. The process was slow, but it caused the iron to separate from the rock, creating a slag. Those who were working with the iron would keep on heating and hammering the iron, a process that mixed the iron with oxygen and took out the carbon. The result was almost pure iron … easy to work with, but it couldn’t take, or keep, a good edge, and so was useless for weapons. It came to be known as wrought iron instead. In the East, iron was being melted and then cast. Cast iron has more carbon in it than wrought iron, which makes it better for weapons. However, it is also brittle. What was needed was a way to make steel. A man named Benjamin Huntsman took out a patent in 1740; he had a process that he used to make steel springs for clocks. His process began with wrought iron. He used a blast furnace to melt it in a crucible made of clay, then added pure charcoal to the metal he had melted. This created an alloy that could be used to cast strong, flexible springs. Because of the process he developed, Benjamin Huntsman is credited with the invention of modern metallurgy. As an interesting side note, his work led to the creation of nautical chronometers. Mariners had been unable to navigate in any kind of a precise way until then because they could not figure out exactly where they were from east to west. Having nautical chronometers made it possible for them to navigate globally for the first time with real confidence. Iron became most useful after scientists began to understand the chemistry involved in the process of making it, and especially the role of carbon in making iron hard. Acquiring the necessary knowledge took thousands of years. Development of the periodic table helped. In the center of the periodic table, there are actually three metals that are considered to belong to the iron family, or triad, because of their similarity to each other: iron, cobalt, and nickel. Clean cobalt has a pink tinge; clean nickel has a yellow tinge and can be given a high polish. Manufacturers use nickel as the chromium undercoat for chromium plating because the results are better than they would be with iron. Cobalt and nickel do not rust as easily as iron. At 4.6 percent, iron is the fourth most common element in the crust of the earth, but it is usually not concentrated except in meteorites. Iron is most often found in the form of

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