William Kelly (inventor)

William Kelly (August 21, 1811 – February 11, 1888), born in Pittsburgh, Pennsylvania, was an American inventor. He is credited with being one of the inventors of modern steel production, through the process of injecting air into molten iron, which he experimented with in the early 1850s. A similar process was discovered independently by Henry Bessemer and patented in 1855. Due to a financial panic in 1857, a company that had already licensed the Bessemer process was able to purchase Kelly's patents, and licensed both under a single scheme using the Bessemer name. Kelly's role in the invention of the process is much less known.

Kelly studied metallurgy at the Western University of Pennsylvania. Instead of getting a job as a scientist, Kelly, his brother, and his brother-in-law started a dry goods and commission business, which they called McShane & Kelly. After a fire destroyed their warehouse, William and his brother John decided to move to Eddyville, Kentucky in 1847 to enter the iron industry.

In 1846, they purchased an iron manufacturing company in Lyon County on the Cumberland River, called Eddyville iron-work. They then renamed the factory Kelly & Company.

Before the technique of injecting air into molten iron was re-discovered by Kelly and by Bessemer, iron was available as cast iron, a strong but brittle metal made in a blast furnace by treating iron ore with coke derived from coal, and wrought iron, a more malleable and flexible metal made by heating iron ore in a low oxygen environment in a bloomery heated by charcoal and producing "blooms", which were 100 to 200 pound lumps of very low carbon iron mixed with slag. The blooms then had to be worked repeatedly by hammering with a helve hammer or later a steam hammer and folding it to work out the slag. This could in turn be converted to steel by heating it for prolonged periods sealed in stone boxes with charcoal, to add back carbon. The resulting steel could then be formed into larger shapes by heating it to welding temperature and hammering it together into a mass. Other laborious and expensive methods made small amounts of steel from special ores.

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