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.
Traditional methods Before the technique of injecting air into molten iron was re-discovered by Kelly and
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. His iron workers may have contributed to his discovery. According to Kelly's biography, in 1854 he hired Chinese iron workers through a New York teahouse. Historian of metallurgy Donald Wagner notes that a similar process was already extant in China, and that Kelly's Chinese iron workers were likely familiar with how molten cast iron behaved under an air blast. The engineer William Phillips, after a trip to Eddyville, wrote in 1899 that "the Chinese had refined iron by blowing air into it a great many years ago, and I have thought that Kelly, in asking for Chinese laborers, would naturally require the services of those who had some knowledge of the iron business." Kelly was college-educated in metallurgy, while Bessemer in his autobiography described no education, other than a practical knowledge of
typecasting and
machining learned at his father's type foundry, stating in 1854, "My knowledge of iron metallurgy was at that time very limited...", but somehow he was able to build, without a long series of progressive improvements, a functioning
converter to blow air into molten iron and convert it to steel. However, Bessemer was a renowned inventor of many industrial processes before he invented the Bessemer process and the potential of blowing air through iron had long been known about before either Bessemer or Kelly applied for a patent, such as in the finery process and in experiments undertaken in the 1840s by
James Nasmyth. In September 1856, Bessemer's patent was reported by
Scientific American. Kelly wrote a letter to the magazine in October 1856 describing his earlier experiments and asserted that the English workmen at his plant had informed Bessemer of Kelly's experiments. Kelly writes, "I have reason to believe my discovery was known in England three or four years ago, as a number of English puddlers visited this place to see my new process. Several of them have since returned to England and may have spoken of my invention there." Kelly's son would later make the unsubstantiated allegation that Bessemer had personally visited Eddyville to secretly learn from Kelly's experiments.
Renewal of patent In 1871, the
U.S. Patent Office granted Kelly a renewal of his patent for 7 years while rejecting applications for renewal by Bessemer and
Robert Forester Mushet, who had also received patents for the process. Bessemer's renewal was rejected for the sole reason that his British patent with which it had been made co-terminal had duly expired at the end of its 14 years of life, and it would have been inequitable to give Bessemer protection in the United States while British iron-masters were not under similar restraint. Had it not been for this consideration, Bessemer probably would have been granted a renewal.
Kelly's bankruptcy The financial
panic of 1857 resulted in Kelly's bankruptcy, and he was forced to sell his patent. With the patents jointly licensed, invention priority disputes became of little interest to the business world. Kelly received only about 5% of the patent
royalties paid to Bessemer, and Bessemer's name was used for the process. Bessemer already had a well known steel making operation in England, and Kelly was little known.
Bessemer Steel The companies owning the Kelly and Bessemer patents began selling the product under the name "Bessemer Steel" in 1866. The Bessemer process greatly reduced the cost of steel and improved the quality, making possible the industrial growth of the United States from 1865 until the early 1900s. The Bessemer process was replaced by the
open-hearth process in the early 20th century. ==Kelly's later life==