So, in keeping with the original intention of this thread.
Hearth:
A brick, stone or concrete structure used to house a fire.
Furnace:
A vessel used to smelt ore or refine smelted ore (pig iron) that traditionally uses forced air to increase the heat.
Forge:
A structure that provides a heat source to bring metal to a working temperature for fabrication.
These are a bit generic, but do they make sense?
Pete
Pete,
Those terms are quite percise enough, even in translation. Those are essential functions. The only change I would suggest is that
forging was sometimes used to "squeeze" slag out of iron, to close up voids/porosity, and to improve crystal structure.
Furnace is easily most complex one in practice and can overlap sometimes with
hearth. They were used to "freshen" iron, that is remelt it to reduce/remove impurities, usually slag (a feature of Vallon hearth/forges and done in first of two hearths/forges), to homogenize composition, as well as in a wide variety of methods to make steel(s), eg., blister steel, crucible steel, bessemer steel, etc., etc.
In another aspect, even long, long ago irons and steels of different physical properties were used for different purposes, in civilian as well as military production.
On a side note, at least in Sweden, again long, long ago, there were ores said to be "steel ores". These were rather difficult to characterize then because of lack of knowledge and means of detection. Hindsight would note that these "steel ores" had accessory minerals that contributed Mn, etc., resulting in "natural" alloys and/or unappreciated aspects of smelting and forging resulted in suitable C contents.
Niklas
