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swords they produced were good, mediocre and a few really bad. These last they threw back into the pot to be re-melted and re-forged. What they did know was that if they used ore from a specific place, and did certain things by rote, taking a specified time to do it, and in a certain manner, they frequently came up with a good sword blade. And rarely, a truly superb sword blade appeared. But they did not know why.
    The real secret to this was simply carbon content in the iron. But since the science of chemistry and metallurgy had not yet been developed, no one knew it. The average person is quite surprised to learn how late it actually was before the impurity, carbon, was proved to be what turned iron into steel. Some recent discoveries in England have shown that very high quality steel was produced in England in the "Dark Ages" (circa 476–1000 AD). Hamwic was a Saxon port that is under modern Southampton. Much of it has now been excavated, and a very interesting discovery was made. Several blooms of very high quality steel were found, plus several knives with high quality steel edges. These blooms are homogenous steel, with about two percent carbon. Properly forged, this could produce exceptional quality blades.
    Shortly before this discovery, another one equally fascinating was announced. It seems that a monastery, abandoned when Henry VIII split from the Catholic Church, was also a metal producing factory. This is not unusual in itself. But what is unusual, is that the process they used was identical to the Bessemer process that was invented by Sir Henry Bessemer in the 19th century, and was in use in manufacturing until quite recently.
    In 1740, Benjamin Huntsman, a maker of watch springs, found that he could produce much superior steel by melting the steel, allowing the slag to rise to the surface, and then skimming it off. This is much the same technique as was used in producing Wootz steel of India. But carbon wasn't discovered until 1774 by Swedish metallurgist Sven Rinman. In 1786 French chemist Guyton de Morveau showed that the substance isolated by Rinman was carbon, introduced into the iron, that turned the iron into steel.
    As early as 1540 AD an Italian had suggested that steel was the "pure" form of iron, and to achieve this purity the iron was heated up and charcoal, leather, and other such substances added to help burn out the impurities. Since charcoal and leather both contain carbon, he was on the right track, but going in the wrong direction. It was the impurities—sulfur, phosphorus, nitrogen, hydrogen, total oxygen, and sometimes carbon—that frustrated steel production. Modern steelmakers grapple with these impurities today, but with a clear understanding of what they are fighting. The ancient blacksmith could only fall back on empirical knowledge gained from trial and error.
FROM IRON TO STEEL
    Let us take a look at iron and what it can and cannot do. Hollywood, popular fiction, and our own wishful thinking have given to swords properties and abilities that simply do not exist in the real world. Martial arts movies have the hero jumping straight up for twelve feet, and sword films depict blades cutting down large trees, shearing through metal and stone with ease, hitting other blades edge to edge, and never showing a scratch.
     
    Samples of Peter Fuller's modern reproduction plate armor and helmets
Photos by Peter Fuller.
     
    Iron is malleable and not too heavy. It can be worked cold, and in thin sheets can be made to take on all sorts of shapes (witness plate armor). Iron is chemically quite active, and will combine readily with many substances. When heated to a cherry red it becomes plastic and can be shaped easily. Work hardening will add a small amount of toughness to iron. But if it is hammered cold too much, it will begin to crack, and even when work hardened it will not have a great deal of toughness. If you add carbon to the iron, the crystalline structure changes. And so do the properties