How did the Bessemer converter change steelmaking?

The Bessemer converter revolutionized steelmaking by enabling the first method for the mass production of steel. Before this innovation, steel was difficult and expensive to produce in large quantities.1

The process functions by blowing air through molten pig iron within a pear-shaped vessel. This oxidation process removes impurities like silicon and carbon, while the heat generated by these chemical reactions keeps the metal molten without requiring additional fuel. This allowed for the rapid production of steel ingots in as little as 15 minutes.12

While the original design struggled with phosphorus-rich ores, the later development of the Thomas-Gilchrist converter—which utilized a basic lining of limestone or dolomite—allowed for the processing of a wider variety of iron ores. The resulting availability of low-cost steel transformed building construction and replaced iron in critical infrastructure, such as railroad rails, fueling significant industrial growth by the turn of the 20th century.12