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.
Inside diameter (of a coil).
Immersion Etching
Method in which a microstructure is dipped face up into etching solution
and is moved around during etching. This is the most common etching method.
Impact Tests
Tests to determine the energy absorbed in fracturing a test specimen at
high velocity. There are various kinds of impact tests, such as charpy,
izod, drop weight, etc.
Inclusions (Non-metallic Inclusions)
Refers to a defect when particles of nonmetallic impurities, usually
oxides, sulfides, silicates, refractories and such, which are the products
of deoxidation, are insoluble in the matrix and are mechanically held in
steel during solidification.
Inclusion Count
Determination of the number, kind, size, and distribution of non-metallic
Induction Hardening
A surface-hardening process in which only the surface layer of a suitable
ferrous workforce is heated by electrical induction to above the upper
transformation temperature and immediately quenched.
Induction Process
A process in which the heating is done by eddy currents generated in the
charge by the induction coil surrounding the charge. Depending upon the
frequency used, the process is called low frequency, medium frequency and
high frequency melting.
A form of semi-finished steel. Liquid steel is teemed (poured) into
vertical cast iron moulds, where it slowly solidifies. Once the steel is
solid, the mould is stripped, and the 25- to 30-ton ingots are then ready
for subsequent rolling or forging.
Ingot Corner Segregation
A longitudinal plane of relatively impure steel arising from segregation
occurring in the region of a corner of an ingot.
Ingot Iron
Very low carbon steel generally made in the open hearth in which all the
other elements are removed to the maximum extent possible. Some of the
commercial products falling under this group have less than 0.1 percent of
all elements put together.
Ingot Mould (Mould)
The container, usually made of cast iron, into which molten steel is poured
and allowed to solidify.
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 steel making, 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.
A piece of steel permanently fixed in the die, which may be used to fill a
cavity or to replace a portion or the whole of the impression.
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. See Mini Mills.
Integrated Steel Producer
A steel company which manufactures solid steel products; starts with raw
materials such as iron ore, flux, etc, to make molten iron; converts the
molten iron to liquid steel in the steel making furnaces and processes
liquid to solid steel products.
Inter Annealed Wire
Wire drawn to an intermediate stage, annealed and drawn to the size
Inter-Chemical Gauge
Wet film thickness can also be measured using an Inter-chemical Gauge. A
graduated circular cam is rolled against the plate between two parallel
rollers. The wet film thickness is then read directly on cam at demarcation
of coating wetting the cam.
Intermediate Annealing
Annealing wrought metal at one or more stages during manufacture and before
final thermal treatment.
Intermediate Temper
A cold rolled hardness range specified with a 15-point Rockwell B spread.
See Quarter Hard Temper and Half-Hard Temper.
Internal Cleanliness
Measure of number and types of non-metallic inclusions such as oxides,
sulfides or silicates.
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.
Interrupted Aging
Aging at two or more temperatures by steps and cooling to room temperature
after each step. Compare with progressive aging and step aging.
Interrupted Quenching
Quenching in which the metal object being quenched is removed from the
quenching medium while the object is at a temperature substantially higher
than that of the quenching medium.
IPM (In-Process Material)
An identifiable piece of steel; can be a slab, coil, or a bundle of sheets,
or several slit mults banded together.
Iron Carbide
One of several substitutes for high-quality, low-residual scrap for use in
electric furnace steel making. Iron carbide producers use natural gas to
reduce iron ore to iron carbide.
Iron Notch
The opening for removing the liquid iron from the blast furnace. The
opening on the inside of the furnace is larger than that on the outside so
that the tapping hole can be drilled horizontally or at different angles.
Although most of the older furnaces had only one iron notch, modern large
blast furnaces have two or three and a few very larger ones have four.
Iron Ore
Mineral containing enough iron to be a commercially viable source of the
element for use in steel making. 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 form. It is of two types : containing ferric oxide
(Hematite) or ferro-ferric oxide (Magnetite).
Iron-Zinc Alloy Coating
See Galvanized Steel.
ISO Codes
The codes that designate the amount of contamination in the oil.
Isolate (Isolation)
To remove a boiler, or any particular part or system of a boiler, form
service by closing the manual valves.
Isothermal Annealing
It is a type of full annealing in which the steel first is cooled to the
temperature at which it is desired to have transformation occur, at a rate
sufficiently rapid to prevent any structural change above that temperature.
The steel then is held at the selected temperature for the time necessary
to complete such transformation.
A term indicating equal physical or mechanical properties in all directions
within a material.
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