Seldom has Dofasco not been an early
adopter of new technology. However, by
the mid 1980s when most other mills
were making slabs via continuous casting,
Dofasco was still pouring ingots and
driving them on specialized trucks to hot
mills to be rolled into coils.
While most conventional ingot operations
would see the ingots poured, go to
soaking pits, onto a slabbing mill, then sit
in a reheat furnace queue before being
sent to the rolling mill, Dofasco had a
different take. The company’s process
skipped the extra time and energy
demand of the reheat furnace by sending
the ingots by truck straight to the
soaking pits, inline slabbing mill then hot
rolling mill. The process had become so
efficient that for a long time there was no
incentive to change.
In typical Dofasco fashion, the approach
was born out of a challenge – not enough
capital to build a reheat furnace during
the previous expansion. While the process
was a matter of necessity, it also came
with two major benefits: lower energy
costs and higher yields. Lower energy as
there was no reheat furnace to run and
higher yield because there was no loss
of the scale jacket (the iron oxide that
formed on the outside of the slab as it
went through the reheat furnace).
When continuous casting technology
pushed on the scene in the 1960s,
energy savings and higher yield were
touted as its major benefits. Energy
savings came from not needing soaking
pits, while higher yields were the result of
avoiding double scale loss in the reheat
furnace and slabbing mill.
But Dofasco was already charging hot,
didn’t have a reheat furnace and didn’t
have as high scale loss. To help, the
company also partly utilized the ability
to pour liquid steel into the ingot molds
from the bottom instead of the top which
helped with the quality. There was simply
no economic incentive to change.
Only when the No. 1 Steelmaking and
No. 1 Hot Mill approached end of life
and continuous casting began to offer
increasingly better surface quality for
slabs did the process look attractive.
A strategy was set to put a slab caster
at the new No. 2 Steelmaking, which
was originally built making ingots until
the caster was completed. When the
state of the art slab caster was started in
the company’s 75th anniversary
year, ingots from No. 2 Steelmaking
were retired.
The new process allowed for the
continuous pour of liquid steel into the
slab mold that methodically makes its
way down the two storey high caster,
forming one continuous slab along the
way before it is torch cut into smaller
slab lengths.
With the advent of the new continuous
caster and the return of a difficult
market, No. 1 Steelmaking and No. 1 Hot
Mill were shuttered.
Casting: a come-from-behind
move on the company’s
th anniversary
Dofasco’s No. 1 Continuous Casting facility was
commissioned in 1987, while No. 2 Castor,
pictured here, was commissioned in 1996.