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 - Ingot iron (Steel)
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wrought iron.
751
The amount of carbon thus absorbed by the iron depends upon the
temperature, the higher it is, the more carbon unites with the iron, while the time of
the heating principally helps only to make the carbon penetrate more easily from
the surface of the iron to its center.
Since in this process no substances leave the iron, it is necessary that it is
from the beginning very low in silicon, phosphorus, and sulphur.
The Swedish hearth-fined iron, made from the most phosphorus free ores of
Sweden, such as those from Dannemora and Persberg, etc., is an excellent material
for making blister steel. During the whole of the past century, blister steel has
been made in Sweden, but only in small quantities, 1,000 to 2,000 tons annually.
The furnaces here used are ordinary English blister steel furnaces with two
chests, each holding 10 tons of bar iron, for the packing of which is required 17
hectoliters of pulverized birch-charcoal, dampened with a little salt water. The
consumption of fuel depends upon how large the percentage of carbon is to be in
the steel, but is on an average 3’ 5 cubic meters of fir and 2 cubic meters of
birch-wood per ton of blister steel. The time required for a charge is three to four
weeks. One week is required for the packing of the bar iron in the chests,
about one week and a half for the burning, and about the same time for the
cooling of the furnace. During the cooling, the amount of carbon is increased
by about 0’3 %. — In 1901, 701 tons of blister steel were produced in six
furnaces which were then in operation.
Crucible Steel. There are only two works in Sweden for making
crucible steel, one at österby, the other at Vikmanshyttan.
At Österby, the Dannemora steel, so renowned for Its excellent quality, is
produced, the raw-material for which is blister steel made by Walloon-forging
of first-class Dannemora pig iron. The steel works, which have regenerative
furnaces for heating the crucibles, were founded in 1871. The crucibles are made
at the works from English fire clay mixed with a few per cent of coke. They
are subjected to a very slow drying process and are brought to a red heat before
being put into the crucible furnace. Each crucible is charged with 20 kilograms
of blister steel together with a few other admixtures, and the melting is done in
about four hours. Thus, three heats are made with the same crucibles in twelve
hours, after which they are discarded. In the producer for the crucible furnace
Table 108. Imports and Exports of part of the Iron and Steel manufacture.
Metric tons à 2,204 lbs.
Average for the years Rails, etc.1 ’ Plates. Average for the years Rails, etc.1 Plates.
Imports. [-Ex-pom.-] {+Ex- pom.+} Imports. Exports. Imports, s ports. Imports, i Exports.
Note. Rails are reported in the Mining Statistics as heavier manufactures but in the
Commercial Statistics are included among Iron and Steel-ware. — Plates reported just above
comprise all sorts, and are entered in full in the Commercial Statistics under the head of
•Ketals, unmanufactured or partly manufactured»; in the Mining Statistics, entry is made
only of »heavy plates».
1 Including Bleepers, fish-plates, etc.
1861/66.....1 14,848 5 684 621
1866 70....., 3,863 161 1,271 644
1871/75.... 38,009 488 3,344 828
1876/80.....1 26,392 270 3,577 1,482
188185.... . 25,357 19 6,901 2,591
1886/90..........25,851 168 4,631 5,076
i i
1891/95.....i 29,537 160 1 3,723 3,489
1896/00.....i 52,706 945 9,331 3,066
In 1898 . J 55,014 1,082 I 9,502 3,019
» 1899... I 87,453 1,899 8,367 2,933
» 1900....! 45,424 604 [ 12,356 2,441
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