Henry Bessemer - Bessemer Process

Bessemer Process

Henry Bessemer worked on the problem of manufacturing cheap steel for the purposes of ordnance production from 1850 to 1855 when he patented his method. On 24 August 1856 Bessemer first described the process to a meeting of the British Association in Cheltenham which he titled "The Manufacture of Iron Without Fuel." It was published in full in The Times. The Bessemer process involved using oxygen in air blown through molten pig iron to burn off the impurities and thus create steel. James Nasmyth had been working on a similar idea for some time prior to this. A reluctant patentor, and in this instance still working through some problems in his method, Nasmyth abandoned the project after hearing Bessemer at the meeting. Bessemer, however, acknowledged the efforts of Nasmyth by offering him a one-third share of the value of his patent. Nasmyth turned it down as he was then about to retire.

Many industries were constrained by the lack of steel, being reliant on cast iron and wrought iron alone. Examples include railway structures such as bridges and tracks, where the treacherous nature of cast iron was keenly felt by many engineers and designers. There had been many accidents when cast iron beams collapsed suddenly, such as the Dee bridge disaster of May 1847 and later failures such as the Wooton bridge collapse and the Bull bridge accident of 1860. The problem recurred at the Tay Bridge disaster of 1879, and failures continued until all cast iron under-bridges were replaced by steel structures. Wrought iron structures were much more reliable with very few failures.

Though this process is no longer commercially used, at the time of its invention it was of enormous industrial importance because it lowered the cost of production steel, leading to steel being widely substituted for cast iron. Bessemer's attention was drawn to the problem of steel manufacture in the course of an attempt to improve the construction of guns.