pa1778data.pdf

U.S. STEEL DUQUESNE WORKS
HAER NO. PA-115
(Page 161)
converter on rails by a dinky. The converter was then turned
down to a horizontal position, so as to bring the tuyeres well
above the bath, and the molten iron was poured into its mouth by
the slowly tipping ladle. When the molten charge was completed,
the air blast, under sufficient pressure to prevent the metal
from flowing into the tuyeres and also to force the air through
the liquid, was turned on. The vessel was then brought to a
vertical position and the scrap was added from the scrapping
floor by means of a chute.
The blow occurred in three distinct stages. During the
first stage, when silicon and manganese were eliminated from the
charge, dense brown fumes which were shortly succeeded by a dull
red, short flame protruded from the mouth of the vessel. This
action lasted about six minutes. The second stage of the blow or
"boil" produced the elimination of carbon from the bath which
lasted for about eight minutes. During this period, the flame
increased, both in length and luminosity, until it reached a
length of thirty feet or more. The final stage or end point
witnessed a sudden drop in the flame's length and luminosity.
After the end point had been reached, the converter was
turned down into the pouring position and the blast air was
turned off. While the molten steel was carefully poured into a
teeming ladle, so as to prevent as much slag as possible from
escaping with the steel, the metal was deoxidized and
recarburized. By adding materials such as ferromanganese,
Spiegel, anthracite coal, ferrosilicon, and pig iron to the
teeming ladle as the metal was being poured, the blower was able
to control the carbon content of the steel, deoxidize it, and
improve its quality. The mix of materials added during this
operation was determined by the product which was about to be
rolled. For example, if it was required to produce a soft steel,
such as skelp for rolling pipe, hot ferromanganese was added to
raise the percent of this element to .40. If the final product
was to be steel rails, a molten spiegel mixture composed of
spiegel, ferrosilicon, and pig iron was used as the
recarburization agent.
When the pouring and its concomitant recarburization
operations were completed, the converter was inverted and the
slag which did not flow out with the steel was dumped onto a
small flat car beneath the vessel. A jib crane then transferred
the ladle to the front of the steel-framed platform at the
teeming aisle where the steel was "teemed" into ingot moulds
which were set on flat cars running on narrow gauge tracks
alongside the platform. Teeming consisted of spotting the
teeming hole in the bottom of the ladle directly over an ingot
mould and raising the ladle's stopper assembly so that the molten