The most frequently used terms and definitions,
related to iron castings, according to ASTM A 644 - 85 are
Austenitize - to convert the matrix of a ferrous alloy to
austenite by heating above the transformation temperature.
Batch - the component raw materials properly weighed,
proportioned, and mixed for delivery to a processing unit. Also,
the product output from a processing unit in which there is
essentially no product output until all component materials are
charged and processed.
Carbide, primary - carbide precipitated in cast iron
Cast iron - a generic term for a series of alloys
primarily of iron, carbon, and silicon in which the carbon I in
excess of the amount which can be retained in solid solution in
austenite at the eutectic temperature.
Cementite - a very hard and brittle compound of iron and
carbon corresponding to the empirical formula Fe3C, commonly
known as iron carbide.
Cementite, primary - cementite precipitated in cast iron
during solidification. Also known as primary carbide.
Chilled iron - a cast iron that would normally solidify
as a gray cast iron which is purposely caused to solidify as
white cast iron locally or entirely by accelerated cooling
caused by contact with a metal surface, that is, a chill.
Direct reduced iron - iron ores that have been reduced to
essentially metallic iron by heat and reducing agents, but
without melting, and processed into suitable shapes for use as a
charge material in a melting operation.
Dual metal - two metals of different composition that are
fusion bonded at all interfacial surfaces by casting metal of
one composition against metal of a second composition.
Ductile iron - a cast iron that has been treated in the
liquid state so as to cause substantially all of its graphitic
carbon to occur as spheroids or nodules in the as-cast
Ferritize - to increase the quantity of ferrite in the
matrix of a ferrous casting through an appropriate heat
Ferritizing anneal - the process of producing a
predominantly ferritic matrix in cast iron through an
appropriate heat treatment.
Graphite, compacted - a graphite shape that is
intermediate between flake graphite and nodular graphite that
typically appears in a polished section as thick flakes with
Graphite, flake - an irregularly shaped particle of
graphite, usually appearing in a polished section as curved
plates, such as found in gray cast irons.
Graphite, nodular - spheroidal shaped graphite typically
found in ductile irons and compact clusters of graphite
typically found in malleable irons.
Graphite, primary - graphite precipitated in cast iron
Graphite rosette - arrangement of graphite flakes in
which the flakes extend radially from centers of crystallization
in gray cast iron.
Graphite, spheroidal - spheroidal shaped graphite having
a polycrystalline radial structure, usually found in ductile
iron and to a controlled, limited extent in compacted graphite
Graphitize - to precipitate graphite in an iron-carbon
Gray iron - cast iron that has a relatively large
proportion of the graphitic carbon present in the form of flake
graphite. The metal has a gray fracture.
Heat - the total molten metal output from a single
heating in a batch melting process or the total metal output
from essentially a single heating in a continuous melting
operation using basically constant charge and processing
conditions and targeted at a fixed metal chemistry at the
furnace spout. A heat can also be defined as a fixed time period
for a continuous melting operation provided that it is shorter
than the time period covered by the above definition.
Inoculating alloy - an alloy added to molten iron for the
principle purpose of nucleating a primary phase such as
graphite. Inoculating alloys are frequently used to avoid the
formation of primary carbide by enhancing the nucleation of
Malleable, ferritic - a ferrous alloy that is cast as
white is converted by an appropriate heat treatment to a
microstructure of temper carbon embedded in a ferritic matrix
essentially free of pearlite and carbide.
Malleable iron - a cast iron of such composition that it
solidifies as white iron, which upon proper heat treatment is
converted to a metallic matrix with nodules of temper carbon.
Malleable, pearlitic - a ferrous alloy that is cast as
white iron but which is converted by an appropriate heat
treatment to a microstructure of temper carbon embedded in a
matrix containing a controlled quantity, form, and distribution
of pearlite or tempered martensite.
Malleableize - to convert white iron into malleable iron
through an appropriate graphitizing heat treatment.
Melt - the total molten metal produced in a single heat.
Merchant pig iron - pig iron produced for commercial sale
Mottled iron - a cast iron containing a mixed structure
of gray iron and white iron of variable proportions. The
fracture has a mottled appearance.
Nodular graphite - graphite in the form of nodules or
spheroids in iron castings.
Nodularity - the volumetric proportion of spheroidal or
nodular graphite to total graphite in a ductile iron or a
compacted graphite iron matrix.
Nodularity, degree of - the volumetric proportion of
spheroidal or nodular graphite to total graphite in a ductile
Nodulizing alloy - an alloy added to molten iron for the
primary purpose of causing the formation of spheroidal graphite
Pig iron - the high carbon iron product obtained by the
reduction of iron ores, typically in a blast furnace or an
electric furnace, and cast into uniform shapes having physical
and chemical characteristics suitable for end as foundry melting
Sample - one or more portions of a liquid or solid
material taken in an unbiased manner from a batch, heat, lot or
process stream to be representative of the whole, for subsequent
testing to determine the chemical, physical, mechanical, or
other quality characteristics of the material, or combination
Temper carbon - compact aggregates or nodules of graphite
found in malleable iron as a result of heat treatment.
Test bar - a bar-shaped coupon that is tested with or
without subsequent preparation for the determination of physical
or mechanical properties.
Test coupon - specially designed casting, or portion
thereof, that is used to provide a representative sample of the
iron from which it was cast.
Test lug - a sample produced as an appendage on a
casting, that may be removed and tested to qualify the casting
or the iron which it was produced.
Test specimen - a test object, suitably prepared from a
sample, for evaluation of the chemical, physical, mechanical, or
metallurgical quality of the sample.
Treated iron - molten cast iron to which all basic alloys
and nodulizing alloys have been added but not necessarily all
inoculating alloy additions.
White iron - cast iron in which substantially all of the
carbon is in solution and in the combined form. The metal has a
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