In response to GJuleff:
I agree entirely that the word "bloomery" to define a furnace is now confusing.
It was used originally of course because a solid-state bloom of forgeable,
usually low to moderate carbon , iron was produced. However suitable change in
ore to fuel ratio and in rate of air supply will make iron of higher carbon
content either as a bloom or molten, some times both at once. What was novel in
Gill's Sri Lankan furnace was the demonstration that this had been done long ago
and with natural draft air supply helped by wind. Her field work and paper in
Nature were very well done, and very interesting to me in that it gave good
technical data, which is not done often enough.
Speaking of names of things, "Crucible Damascus Steel" is confusing
because it assumes too much.
[log in to unmask] wrote:
> In response to Ned Rehder's comments about the quality of Sri Lankan steel,
> during the smelting trials carried out in 1994 in the wind-powered
> west-facing furnaces of Samanalawewa we achieved average furnace temperatures
> in excess of 1440C and produced both low-carbon iron and hypereutectoid
> steels that were homogeneous and slag-free (they had been molten) (Nature,
> vol. 379, no.6560, 1996). A substantial percentage of the metal produced in
> our trials was hypereutectoid steels and, given the design and operation of
> the furnace, it was apparent that if we were able to produce such steels then
> experienced practioners in the past would have done the same but with greater
> consistency and efficiency. To not do so would require intentional (and
> pointless) disabling of the smelting process. This technology was the basis
> of a widespread industry supporting many thousands of furnaces at a time when
> Serendib steels are specifically referred to in Islamic text literature.
>
> The important issue here is not neccessarily whether high-quality high-carbon
> steels were made directly during smelting or could only be produced in a
> crucible process but recognising the potential of differing smelting
> processes to produce, intentionally and consistently, a range of ferrous
> products. It is quite possible that high-carbon steels produced in Sri Lankan
> furnaces were further 'refined' in a crucible process. If we could move away
> from labelling all 'pre-industrial' smelting processes as 'bloomery', thereby
> presupposing a 'bloomery' type product, we might begin to appreciate the
> range of ferrous processes and products possible in early technology,
> particularly in Asia.
>
> Gill Juleff
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