The Bessemer process was an important steel-making process developed in the mid-19th century. It was the first inexpensive industrial process for the mass production of steel from molten pig iron. The process is named after its inventor, Henry Bessemer, who took out a patent on the process in 1855. The process allowed the production of steel in large quantities, which was previously only possible using more expensive methods such as the crucible process. The Bessemer process involved blowing air through molten pig iron to burn off carbon and other impurities, resulting in a stronger and more durable form of steel.