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I-Beams
Structural sections on which the flanges are tapered and are
typically not as long as the flanges on wide-flange beams.
The flanges are thicker at the cross sections and thinner
at the toes of the flanges. They are produced with depths
of 3-24 inches.
Ingot
A form of semi-finished steel. Liquid steel is teemed (poured)
into molds, where it slowly solidifies. Once the steel is
solid, the mold is stripped, and the 25- to 30-ton ingots
are then ready for subsequent rolling or forging.
Inmetco
WHAT Inmetco is a coal-based process
similar to FASTMET that uses iron oxide fines and pulverized
coal to produce a scrap substitute. Mill scale and flue dust,
inexpensive byproducts of steelmaking, can be mixed with the
iron oxide fines. Inmetco, unlike other direct reduction products,
is intended to be hot charged into an EAF, with attendant
energy savings.
HOW The process includes three
steps. First, iron oxide fines, pulverized coal and a binder
are formed into pellets. Second, the pellets, two to three
layers deep, are heated in a gas-fired rotary hearth furnace
for 15-20 minutes to produce sponge iron. Subsequently, the
iron must be desulfurized. The coal in the pellets provides
much of the energy required in the second phase.
Integrated Mills
These facilities make steel by processing iron ore and other
raw materials in blast furnaces. Technically, only the hot
end differentiates integrated mills from mini-mills. However,
the differing technological approaches to molten steel imply
different scale efficiencies and, therefore, separate management
styles, labor relations and product markets. Nearly all domestic
integrated mills specialize in flat-rolled steel or plate.
Interstitial Free Steel
A recently developed sheet steel product with very low carbon
levels that is used primarily in automotive deep-drawing applications.
Interstitial Free Steel's improved ductility (drawing ability)
is made possible by vacuum degassing.
Iron Carbide
One of several substitutes for high-quality, low-residual
scrap for use in electric furnace steelmaking. Iron carbide
producers use natural gas to reduce iron ore to iron carbide.
Iron Ore
Mineral containing enough iron to be a commercially viable
source of the element for use in steelmaking. Except for fragments
of meteorites found on Earth, iron is not a free element;
instead, it is trapped in the earth's crust in its oxidized
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