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The Art of
Steel Making
By Sydney S. Slaven
Steel is defined as a hard strong alloy consisting
principally of iron and containing carbon and sometimes other metals.
It is not difficult to make steel, (it has been likened to making
soup where the various ingredients are boiled to the desired brand).
The difficulty lies in making steel of an excellent quality - this
the steelworkers at the Sydney steel plant did for one hundred years.
In 1957 the DOSCO plant was a fully integrated steel operation which
not only produced iron and steel, but a diversified group of products.
At this time the Sydney plant was a progressive, profitable business
employing over 500 steelworkers and was heading for a record breaking
production year. Although rails were the primary product, (the finest
rail produced in the world), the plant also manufactured billets,
bars, rods, wire and nails. In the following years the plant was
never again to reach such a diversity of product. Therefore, this
is the best year to describe the Sydney steel plants operations.
The three basic ingredients in making steel are coal, iron ore and
limestone. Dosco was able to supply the plant from its own resources.
Coal from their coalfields at Glace Bay and New Waterford was sent
by rail to the Coke Ovens. The iron ore was mined at the Dosco mine
at Wabana NFLD., and shipped to Sydney. Also limestone was also
shipped from the Dosco owned mine at Aquatuna, NFLD.
The first step in making iron was converting the coal into coke
at the Coke Ovens. The Coke Ovens consisted of ovens of brick construction
and each held about 16 tons. The ovens were heated by recycling
hot gases from the reduction of coal to coke. There is a space between
the ovens and this is where the gas was burned. It created a red
hot oven. Coal was placed in the oven and then the oven was sealed.
Gasses were sweated out of the coal rather then being burned out,
leaving the coke product. Gases are the volatile constituents of
coal which are driven off by heat, giving a rich coal gas, thus
the Coke Ovens was self sufficient. Coke was not the only by-product
produced from coal gas. Other salable items that resulted were tar,
ammonia salt and benzol. Also excess coke oven gas was piped to
the blooming mill pits were it was used as a combustible. The coke
was transported to the Blast Furnace.
Iron was produced at the Blast Furnace using a combination of iron
ore, coke and limestone. Iron ore was changed to molten iron using
coke, which acted as a fuel and carbon agent, and limestone which
acted as a cleaning agent. These furnaces ran for years on the gas
produced in making iron. This heated gas was gathered in adjoining
stoves where is was kept hot by checker bricks. Reversing valves
returned this hot gas to the furnace when a cast of iron was being
made. Thusly, a Blast Furnace ran off its own heated gases. The
limestone was lighter than the ore and was used to carry impurities
to the top of the heat in the form of slag. The iron was run off
into ladles and was transported to the Open Hearth.
Steel was made in the Open Hearth in six 175 ton tilting furnaces.
These furnaces were heated by bunker c oil which was atomized with
steam and then sprayed through nozzles into the furnace pocket.
Charging a furnace consisted of first a meltdown of scrap steel.
The iron from the Blast Furnace was stored in a metal furnace on
site. When the scrap steel was melted iron was poured out of the
metal furnace into a ladle and this ladle was then poured into the
O.H. furnace itself.
Other alloys were added as needed. Manganese was added to reduce
sulfur and limestone and spar were used to drive out impurities.
The hardness of the steel depended on the amount of carbon. A soft
heat would have a low carbon content of up to .25%, while a hard
steel would require a .45% to 1.5% content. Coke was added to the
molten steel to increase the carbon content as needed. Soft steel,
or low carbon content, was used to produce bars, rods, wire or nails.
Hard steel or high carbon content went into the production of rails.
We have only to examine a simple nail to understand how critical
carbon content was. If the steel was too soft, low carbon content,
the nail would bend when struck. On the other hand, if the carbon
content was too high, the nail would shatter.
Molten steel was tapped from the back of the furnace by pushing
a billet into the tap hole to release the steel into a waiting ladle.
The impurities in the form of slag came last and they were run off
into a slag ladle. The slag from the Open Hearth and Blast furnace
was a viable commodity as it was used as a foundation in roadbuilding,
basements and also as common fill. Many parts of Sydney sit upon
areas that have been reclaimed from the sea by the use of slag as
a fill. The tapped steel went through a teeming process in which
it was poured into ingot moulds which were transported by a locomotive
along a narrow gauge line to a stripper yard where the moulds were
stripped off what was now a solid ingot, although still glowing
hot.
continued...
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