Henry Bessemer Patents the Steel-Making Process

English inventor Henry Bessemer received a patent for blowing air through molten pig iron to remove carbon and impurities, producing steel in minutes rather than days. The Bessemer converter, a pear-shaped vessel with bottom-mounted tuyeres, reduced the cost of steel production dramatically. Robert Mushet's subsequent addition of spiegeleisen solved early quality problems. Commercial production began in Sheffield in 1858, and by the 1870s Bessemer steel underpinned railway expansion across Europe and North America.