© Science Museum/Science and Society Picture Library
The Steel Age began in the 1850s, when Henry Bessemer, a prolific inventor, undertook crucial experiments aimed at finding a malleable form of iron, strong enough to make gun barrels. Previously, both machine building and civil engineering had mainly relied on wrought iron, which is malleable but relatively soft and weak, or cast iron, which is hard but brittle.
Bessemer produced steel, a form of iron with a much lower percentage of carbon than the 3 percent that is usual in cast iron, by blowing air into molten pig iron, causing some of the carbon to oxidise and burn out. The violence of the chemical reaction sustained the process without the need for the addition of any further fuel.
The example shown here is a converter from a pilot plant used at the works of the Barrow Haematite Steel Company Ltd., Barrow-in-Furness, to produce the first cast of steel in May 1865. The low-phosphorous ore necessary to replicate Bessemer's experimental results was readily available in this area.