blister steel

An historical type of steel obtained by cementation. The iron bars were annealed with coal powder over a lengthy period of time in airtight conditions.

This process, also known as carburisation, increased the carbon content but was complex and expensive. Moreover, only a relatively small amount of steel could be obtained in each firing process. In the 19th century, the importance of this technique soon decreased owing to the spread of puddling. The product was known in England as blister steel.

The furnace itself was the main technological hurdle in producing blister steel economically. The first cementation furnace in England was built at Coalbrookdale around 1620. The bulk of production moved to the Derwent Valley in the northeast as of 1710. Around this time, some cementation furnaces had started up in Birmingham and surroundings (West Midlands) as well as in Sheffield and Rotherham (South Yorkshire).

Since, with the exception of some haematite deposits, iron ores in England (ironstones) were unsuitable for blister steel production because of their phosphorus content, bar iron was imported from the Basque country and from Sweden (especially high-grade iron from Dannemora). In 1737, about 1000 tons of Swedish iron was converted into blister steel in England.

Cite as: blister steel. In: Travel Reports of a Pioneer: Digital Edition of the Travel Journals of Johann Conrad Fischer 1794–1851. Published by Franziska Eggimann. Edited by Franziska Eggimann, Nicolau Lutz, Valerija Rukavina und Christopher Zoller-Blundell. Schlatt 2023, Version 1.2, https://johannconradfischer.com/en/keywords/gfa-keywords-8516, viewed on 7 June 2025.