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Agglomerating Processes
Fine particles of limestone (flux) and iron ore are difficult to
handle and transport because of dusting and decomposition, so the
powdery material usually is processed into larger pieces. The raw
material's properties determine the technique that is used by mills.
SINTER
Baked particles that stick together in roughly one-inch chunks.
Normally used for iron ore dust collected from the blast furnaces.
PELLETS
Iron ore or limestone particles are rolled into little balls in a
balling drum and hardened by heat.
BRIQUETTES
Small lumps are formed by pressing material together. Hot Iron
Briquetting (HBI) is a concentrated iron ore substitute for scrap for
use in electric furnaces.
AISI (American Iron and Steel Institute)
An association of North American companies that mine iron ore and
produce steel products. There are 50 member companies and more than
100 associate members, which include customers that distribute,
process, or consume steel. The AISI has reorganized into a North
American steel trade association, representing the interests of
Canada, Mexico, and the United States.
Alloying Element
Any metallic element added during the making of steel for the purpose
of increasing corrosion resistance, hardness, or strength. The metals
used most commonly as alloying elements in stainless steel include
chromium, nickel, and molybdenum.
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Alloy
Steel
An iron-based mixture is considered to be an alloy steel when
manganese is greater than 1.65%, silicon over 0.5%, copper above 0.6%,
or other minimum quantities of alloying elements such as chromium,
nickel, molybdenum, or tungsten are present. An enormous variety of
distinct properties can be created for the steel by substituting these
elements in the recipe.
Alloy Surcharge
The addition to the producer's selling price included in order to
offset raw material cost increases caused by higher alloy prices.
Annealing
WHAT A heat or thermal treatment process by which a previously
cold-rolled steel coil is made more suitable for forming and bending.
The steel sheet is heated to a designated temperature for a sufficient
amount of time and then cooled.
WHY
The bonds between the grains of the metal are stretched when a coil is
cold rolled, leaving the steel brittle and breakable. Annealing "recrystallizes"
the grain structure of steel by allowing for new bonds to be formed at
the high temperature.
HOW
There are two ways to anneal cold-rolled steel coils batch and
continuous.
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