Full resolution (JPEG) - On this page / på denna sida - Second part - IX. Mining Industry and Metal Production - 2. The Iron and Steel Industry. By the late Prof. J. G. Wiborgh - Wrought iron
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wrought iron.
731
Flattening Hammer.
At the same time as the Lancashire forging was introduced, the blooms were
heated in reverberatory furnaces instead of in hearths, which were called heating
furnaces. Mr. G. Ekman also constructed such a heating furnace, which, with
some alterations, is still used, and is called Ekman’s Heating furnace. As fuel
for this heating furnace, fossil coal, wood, or peat is used; usually, however, a
mixture of these fuels.
One ton of blooms requires 6 cubic meters of charcoal, and one ton of bar
iron, if the heating be done in a »räckhärd», 14 cubic meters; in case the blooms
are heated in a heating furnace, a cheaper fuel can be used, as implied above.
In a Lancashire hearth about 10 tons of blooms can be produced per week.
Franche-Comté forging. After these improved hearths
(Lancashire hearths) had come into use in England for Walloon forging, the
same kind of hearths began to be used in France for the German forging.
This altered German forging was then introduced in this country, in
1853, by the name of Franche-Comté forging. Thus, in a
Franche-Comté hearth the heating of the blooms is done in the hearth, while the
pig iron is melting; the balance of the work is done in the same way as
Lancashire forging. The pig iron ought, however, to have a somewhat
higher percentage of silicon than the Lancashire pig iron. The heating
in the hearth is slow, so that the production is considerably less.
In a Franche-Comté hearth only 3*5 tons of bar iron is produced
per week with a consumption of 13 cubic meters of charcoal and a waste
in heating of about 18 %.
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