Kelly, William(1811–88) iron manufacturer, inventor; born in Pittsburgh, Pa. In Kentucky in the 1840s and early 1850s, he built and operated iron furnaces and was making wrought-iron articles. By 1850 he had discovered that a blast of air blown through molten iron removes many of the impurities found in cast iron of the day, leaving a stronger and more ductile metal. Using what he called this "air-boiling" process, he built seven "converters" between 1851–56 and was effectively making steel. But in 1856 the Englishman, Henry Bessemer, who had independently discovered much the same process, was given a U.S. patent, so Kelly was forced to convince the U.S. Patent Office of the priority of his claim; Kelly's claims were recognized in a patent of 1857. Although subsequent refinements of Kelly's process would contribute greatly to the new "age of steel," Kelly himself went bankrupt in the panic of 1857 and it was the Bessemer converter that achieved commercial success.