Full resolution (JPEG) - On this page / på denna sida - VI. Mining and Metallurgical Industry. General Survey. By C. Sahlin - 2. Iron and Steel Industry. By J. A. Leffler
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
-288
vi. mining and metallurgical industry.
practised. The Walloon hearth is, like the German hearth, open, but
considerably smaller.
In this process is employed pig iron made with cold-blast; the pig-iron is
cast in sand in pigs, called "gösar", having a semicircular cross-section, and these
pigs are about 5 meters long, and have a weight of from 800 to 1 000
kilograms. The pigs are pushed from behind into the hearth, up to the tuyere,
and are there covered with charcoal. After the smelting, the metal is broken
up in the usual manner. The small lumps are cut up into blooms, which are
welded and then hammered out under a hammer.
In this process the phosphorus and sulphur contained in the iron is removed
to a remarkable extent.
(f. Ekman.
Walloon iron is used only for the preparation of blister steel, which is then
smelted in crucibles (crucible steel).
The consumption of fuel is about 150 hectoliters of charcoal per ton of bar
iron. About 1*6 tons of bar iron a day is the output per hearth, the waste
(avbränning) being about 25 %. This iron is therefore very expensive to make.
The Lancashire Process. In the twenties of the nineteenth century a very
important improvement was made in the construction of the forging hearths. In
lieu of the open hearth hitherto in use, the actual smelting-chamber was
surrounded with cast-iron slabs, and furnished with a firebrick arch as a roof, so
that the hearth was closed, and provided with only one working opening. The
bottom of the hearth was kept cooled by a tank of water placed under it, and
<< prev. page << föreg. sida << >> nästa sida >> next page >>
