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1856Disputed

Bulk Steel (Bessemer Process)

The Bessemer process blows air through molten pig iron to burn off carbon and impurities, producing steel quickly and cheaply. It turned steel from a costly specialty metal into an everyday structural material.

Materials & MetallurgyUnited KingdomUnited States

Attribution — Credit is genuinely contested; reputable sources disagree.

Henry Bessemer patented the process in 1856, but William Kelly developed a very similar pneumatic method independently in the United States, and Robert Mushet's addition of spiegeleisen was essential to making the steel usable. Priority was contested.

What counts as the invention: The patent (Bessemer) and the independent invention (Kelly) diverge from the metallurgical fix (Mushet) that made the output practical.

Contributors

Historical impact

Cheap steel built railways, bridges, skyscrapers, and machines at unprecedented scale.

Modern relevance

Later oxygen steelmaking descends from the same air-blown principle Bessemer and Kelly pioneered.

Led to

Related Knowledge Center resources

Sources & further reading

Each citation names the publisher and the exact reference title.

  • Encyclopædia Britannica — technology & biography topic articlesEncyclopædia Britannica · Encyclopedia
  • Science Museum Group Collection & topic articlesScience Museum Group (UK) · Museum
  • Engineering and Technology History Wiki (ETHW)IEEE / United Engineering Foundation · Professional body

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