Cementation process



The cementation process is an obsolete technique for making carbon in the iron. It was apparently developed before the 17th century.

Origins

The process probably originated in Bohemia in the 16th century and was in use in Bavaria in 1601. The process was patented in England by William Ellyot and Mathias Meysey in 1614. At that date, the 'invention' could consist merely of the introduction of a new industry or product, or even a mere monopoly. They evidently soon transferred the patent to Sir steel was found to be undesirable because he could not supply as much good steel as was needed.

Brooke's oregrounds iron. It was so called from the Swedish port of Öregrund, north of Stockholm, in whose hinterland most of the ironworks lay. The ore used came ultimately from the Dannemora mine.

Process

The process begins with salts, called cement powder - which gave the process its name. In larger works up to 16 tons of iron was treated in each cycle.

Depending on the thickness of the iron bars the pots were then heated from below for a week or more. Bars were regularly examined and when the correct condition was reached the heat was withdrawn and the pots were left until cool - usually around fourteen days. The iron had 'gained' a little over 1% in mass from the carbon in the charcoal, and had become heterogeneous bars of blister steel.

The bars were then shortened, bound, heated and hammered, pressed or rolled to become shear steel. Alternatively they could be broken up and melted in a crucible using a crucible steel or cast steel, a process devised by Benjamin Huntsman in the 1740s.

Cementation process for brass

In the early modern period, calamine brass.

References

  • K. C. Barraclough, Steel before Bessemer I: blister steel: the birth of an industry (1985).
  • K. C. Barraclough, 'Swedish Iron and Sheffield Steel' History of Technology 12 (1990), 1-39.
  • P. W. King, 'The Cartel in Oregrounds Iron' Journal of Industrial History 6 (2003), 25-48.
  • R. J. MacKenzie and J. A Whiteman, 'Why pay more? An archaeometallurgical examination of 19th century Swedish Wrought iron and Sheffield blister steel' Historical Metallurgy 40(2) (2006), 138-49.
 
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