The Society has a lease on the site of the remains of a cementation furnace at Bower Spring, Sheffield. Those who know the site will appreciate the need for work to be done to tidy it up and preserve the remains. A few words about the furnace itself may be appropriate and I reproduce below the summary, compiled by the late Dr Ken Barraclough, sent with the appeal letter :
Sheffield's steelmaking reputation was based on production of blister steel in the Cementation furnace and its subsequent refining by the Huntsman crucible process. The Huntsman furnace is preserved for posterity at the Abbeydale Hamlet. Of the 250 Cementation furnaces whose cones rose into the Sheffield skyline in the 1860s, however, only one stands - the sole surviving Doncaster furnace at Hoyle Street. The only other evidence on the ground is the partial survival at Bower Spring.
There were two Cementation furnaces and a Huntsman melting shop at Bower Spring, built around 1828 by Turton Brothers; used by them until 1860, the furnaces were operated by Moss and Gamble until 1911. The Cementation furnaces could together produce up to 700 tons of blister steel per annum.
A Cementation furnace had two sandstone chests, separated by central firebars with flues around the sides of the chests. The arched dome above the chests reflected the heat and the tall conical chimney provided the draught. Into the chests went flat bars of Swedish iron - the purest available - packed between layers of charcoal; the packed chests were sealed and a coal fire kept their contents at bright red heat for several days. This caused diffusion of carbon into the iron, producing bars of blister steel which, after cooling down the furnace, could be withdrawn and either forged into shear steel or melted into crucible steel.
The remains at Bower spring may appear fragmentary, but they provide an excellent opportunity of observing the internal furnace structure. A certain amount of excavation and consolidation is now urgent; given this, an interpretation centre on the site, which would obviously refer to the nearby Hoyle Street furnace, would permit an appreciation of this obsolete method of steelmaking; a vital part Sheffield's history not otherwise available.
(The Cutting Edge - No.7 - 1991)
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