Cheap steel
Blowing air through molten iron makes steel a bulk material rather than a luxury.
- When
- —
- Duration
- 14 years
- Known to
- ± 2 years
- Era
- Industrial, Holocene
Henry Bessemer patents his converter in 1856: forcing air through molten pig iron burns off carbon and impurities in about twenty minutes, cutting the cost of steel by roughly six-sevenths. Steel replaces iron in rails, ships, bridges, machinery and eventually building frames. The Siemens-Martin open hearth follows and allows scrap recycling. Structural steel is what makes the skyscraper and the modern bridge possible.