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Henry Bessemer's creation of high-grade steel in the late 1850s kicked the Industrial Revolution into high gear, changing the world forever. His quest actually began after he invented a new type of artillery shell, but the cast iron guns of the day weren't strong enough to handle the more powerful ordnance. Fisher Investments believes changing raw iron ore into strong and malleable steel that could be mass-produced also allowed new inventions like steam engines, railroads, skyscrapers, and assembly-line manufacturing.
Previously, raw iron ore was traditionally melted by burning charcoal. This process produced carbon emissions absorbed by the raw ore to become usable iron. However, charcoal-making was soon deemed unsustainable because of massive deforestation in Britain. Coal appeared the obvious replacement, but its high sulfur content resulted in very brittle metals. In the early 1700s, the discovery of coke solved the problem.
Coke is coal burnt in the absence of air the same way charcoal is made by burning wood in the absence of air. Limestone added to the mix removed additional impurities. The result was cast iron. By today's standards, with 4 percent carbon, cast iron is still quite brittle (the higher the percentage of carbon, the more brittle the iron or steel). But Bessemer revolutionized the industry by observing that blowing hot air through molten cast iron caused carbon to burn off, allowing the steelmaker greater control over carbon content. Fisher Investments' research shows that this led to mass production of cheap, high-grade steel in what are now known as Bessemer furnaces. Improvements on the original design yielded modern day blast and basic oxygen furnaces. Almost all steel today contains less than 2 percent carbon — considerably stronger and less brittle than pre-Bessemer cast iron.
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