ASTM A644-98(2003)
(Terminology)Standard Terminology Relating to Iron Castings
Standard Terminology Relating to Iron Castings
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Designation:A 644–98 (Reapproved 2003)
Standard Terminology Relating to
Iron Castings
This standard is issued under the fixed designation A 644; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
ausferrite, n—a cast iron matrix microstructure, produced by monly known as iron carbide.
a controlled thermal process, which consists of predomi- cementite, primary, n—cementite precipitated in cast iron
nantly acicular ferrite and high carbon austenite. (See during solidification. Also known as primary carbide. (See
austempered ductile iron.) cementite.)
austempered ductile iron, n—aductilecastironthathasbeen chill, n—anobject,usuallymetal,imbeddedinaportionofthe
produced by a controlled thermal process which results in a mold to accelerate the local rate of heat removal from the
matrix microstructure consisting of predominately acicular metal being cast.
ferrite and high carbon austenite. chill, v—to accelerate the freezing rate of cast iron, usually in
austenitize, vt—to convert the matrix of a ferrous alloy to a localized region, to refine the graphite structure or cause
austenite by heating above the transformation temperature. formation of primary carbides.
batch, n—the component raw materials properly weighed, chill, microstructural, n—a localized region of primary car-
proportioned, and mixed for delivery to a processing unit. bidesinacastingmadefromacastironthatwouldnormally
Also, the product output from a processing unit in which solidify free of primary carbides.
there is essentially no product output until all component chilled iron,n—acastironthatwouldnormallysolidifyfreeof
materials are charged and processed. primary carbide which is purposely caused to solidify as
brittle fracture, n—fracture that occurs without appreciable white cast iron, locally or entirely, by accelerated cooling.
plastic deformation of the material. compacted graphite iron, n—a cast iron that has been treated
brittle fracture area, n—The fraction or percent of the in the liquid state so as to cause its graphitic carbon to occur
fracture surface that formed by brittle fracture. (When in the compacted graphite shape in the as-cast condition.
observed with no or low magnification, brittle fracture (See graphite, compacted and graphite, spheroidal.)
appears whiter and shinier than ductile fracture.) confidence level,n—theprobability,orexpectedpercentofthe
capability index (C ), n—for a stable process, the specifica- times, that the selected percent (P%) of the actual popula-
p
tion range divided by six times the standard deviation. tion lies within the tolerance interval calculated from the
data sample.
~USL 2 LSL!
C 5 direct reduced iron, n—iron ores that have been reduced to
p
6 3 s
essentially metallic iron by heat and reducing agents, but
capability index (C ), n—for a stable process, the smaller of
pk
without melting, and processed into suitable shapes (typi-
the upper capability index (CPU) or the lower capability
cally pellets) for use as a charge material in a melting
index (CPL).
operation.
carbide, primary, n—carbide precipitated in cast iron during
dual metal, n—two metals of different composition that are
solidification.
fusion bonded at all interfacial surfaces by casting metal of
cast iron, n—a generic term for a series of alloys primarily of
one composition against metal of a second composition.
iron, carbon, and silicon in which the carbon is in excess of
ductile fracture, n—fracture that occurs with appreciable
the amount which can be retained in solid solution in
plastic deformation of the material.
austenite at the eutectic temperature.
ductile fracture area, n—The fraction or percent of the
cementite, n—a very hard and brittle compound of iron and
fracture surface that formed by ductile fracture. (When
carbon corresponding to the empirical formula Fe C, com-
observed with no or low magnification, ductile fracture
appears grayer and duller than brittle fracture.)
ductile iron, n—a cast iron that has been treated in the liquid
This terminology is under the jurisdiction of ASTM Committee A04 on Iron
Castings and is the direct responsibility of Subcommittee A04.91 on Editorial statesoastocausesubstantiallyallofitsgraphiticcarbonto
Matters and Nomenclature.
occur as spheroids or nodules in the as-cast condition.
Current edition approved Dec. 10, 1998. Published January 1999. Originally
approved in 1971. Last previous edition approved in 1998 as A644–98.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A 644–98 (2003)
ferritize, vt—toincreasethequantityofferriteinthematrixof lower specification limit (LSL), n—the lowest specified
a ferrous casting through an appropriate heat treatment. value.
ferritizing anneal, n—the process of producing a predomi- M, n—the number of standard deviations, mutually concurred
nantlyferriticmatrixincastironthroughanappropriateheat by the supplier and purchaser, to be used for calculations of
treatment. statistical conformance to such items as minimums, maxi-
graphite, compacted, n—a graphite shape that is intermediate mums, specification ranges, and process capability indices.
between flake graphite and nodular graphite that typically
DISCUSSION—M values of three or less were used in establishing
appears in a polished section as thick flakes with blunt
initialASTM specification limits; higher values of M result in reduced
(compacted) ends.
allowable variability for actual values when the property of interest is
graphite flake, n—an irregularly shaped particle of graphite, bounded on both sides; in the case of a minimum or maximum, a high
value of M can result in the need for excessively high or low mean
usuallyappearinginapolishedsectionascurvedplates,such
property values ( x¯).
as found in gray cast irons.
graphite, nodular, n—spheroidal shaped graphite typically
malleable, ferritic, n—aferrousalloythatiscastaswhiteiron
found in ductile irons and compact clusters of graphite
but which is converted by an appropriate heat treatment to a
typically found in malleable irons. (See graphite, spheroi-
microstructure of temper carbon embedded in a ferritic
dal, and temper carbon.)
matrix essentially free of pearlite and carbide.
graphite, primary,n—graphiteprecipitatedincastironduring
malleable iron, n—a cast iron of such composition that it
solidification.
solidifies as white iron, which upon proper heat treatment is
graphite rosette, n—arrangement of graphite flakes in which
converted to a metallic matrix with nodules of temper
the flakes extend radially from centers of crystallization in
carbon.
gray cast iron.
malleable, pearlitic, n—a ferrous alloy that is cast as white
graphite, spheroidal, n—spheroidal shaped graphite having a
iron but which is converted by an appropriate heat treatment
polycrystalline radial structure, usually found in ductile iron
to a microstructure of temper carbon embedded in a matrix
and to a controlled, limited extent in compacted graphite
containing a controlled quantity, form, and distribution of
iron.
pearlite or tempered martensite.
graphitize, vt—to precipitate graphite in an iron-carbon alloy.
malleableize, vt—to convert white iron into malleable iron
gray iron, n—castironthathasarelativelylargeproportionof
through an appropriate graphitizing heat treatment.
the graphitic carbon present in the form of flake graphite.
maximum (non-statistical), n—the highest acceptable actual
The metal has a gray fracture.
test result; any valid individual test result above the maxi-
heat, n—thetotalmoltenmetaloutputfromasingleheatingin
mum is cause for rejection of the component or material lot
abatchmeltingprocessorthetotalmoltenmetaloutputfrom
being tested.
essentiallyasingleheatinginacontinuousmeltingoperation
All x #Maximum 5 USL
i
using basically constant charge and processing conditions
and targeted at a fixed metal chemistry at the furnace spout.
maximum (statistical), n—the highest acceptable statistical
A heat can also be defined as a fixed time period for a
test result; for compliance, the sample mean ( x¯) plus M
continuous melting operation provided that it is shorter than
standard deviations(s), where M is a matter of agreement
the time period covered by the above definition.
between the supplier and purchaser, must be less than, or
inoculated iron, n—cast iron, either liquid or solid, to which
equal to, the upper specification limit.
one or more inoculating alloys have been added while the
x¯ 1 M 3 s #Maximum 5 USL
iron was in the molten state.
inoculated iron, fully, n—cast iron, either liquid or solid, to DISCUSSION—1—A normal data distribution is assumed for the
population from which the data sample was drawn.
which all molten metal additions, including all inoculating
DISCUSSION—2— M values of three or less were used in establis
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