ASTM B243-00a

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Designation: B 243 – 00a
Standard Terminology of
Powder Metallurgy
This standard is issued under the fixed designation B 243; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.5 Procedure to Evaluate Sintered Parts, 3.3.5
3.6 Removal of Binders, 3.3.6
1.1 This terminology includes definitions of terms that are
4. Postsinter Treatments:
specific to the powder metallurgy industry. These definitions
4.1 Processes, 3.4.1
are helpful in the interpretation and application of powder
5. Miscellaneous:
metallurgy terms.
5.1 Definitions, 3.5.1
2. Referenced Documents 5.2 Processes, 3.5.2
5.3 Materials, 3.5.3
2.1 ASTM Standards:
3.1.2 General:
B 331 Test Method for Compressibility of Metal Powders in
1001 agglomerate, n—several particles adhering together.
Uniaxial Compaction
1002 particulate matter, n—see powder.
3. Terminology
1003 P/M, n—the acronym representing powder metallurgy.
Used as P/M Part, P/M Product, P/M Process, and so forth.
3.1 Powder—Terms associated with production, character-
1004 powder metallurgy, n—the production and utilization
ization, use, and testing of metal powders.
of metal powders.
3.1.1 Table of Contents
1005 powder, n—particles that are usually less than 1000
1. Powders:
μm (1 mm) in size.
1.0 General, 3.1.2
1006 metal powder, n—particles of elemental metals or
1.1 Processes to Produce Powder, 3.1.3
alloys, normally less than 1000 μm (1 mm) in size.
1.2 Types of Powder, 3.1.4
3.1.3 Processes to Produce Powder:
1.3 Shapes of Powder Particles, 3.1.5
1101 atomization, n—the dispersion of a molten metal into
1.4 Additives to Powder, 3.1.6
particles by a rapidly moving gas or liquid stream or by
1.5 Treatment of Powder, 3.1.7
mechanical means.
1.6 Properties of Powder, 3.1.8
1102 granulation, n—the production of coarse metal par-
1.7 Procedures to Evaluate Powder, 3.1.9
ticles by pouring the molten metal through a screen into water
1.8 Equipment to Evaluate Powder, 3.1.10
(shotting) or by violent agitation of the molten metal while
2. Forming:
solidifying.
2.0 General, 3.2.1
1103 classification, n—separation of a powder into fractions
2.1 Processes for Compacting, 3.2.2
according to particle size.
2.2 Conditions of Compacting, 3.2.3
1104 air classification, n—the separation of powder into
2.3 Tools Used for Compacting, 3.2.4
particle size fractions by means of an air stream of controlled
2.4 Phenomena Resulting from Compaction, 3.2.5
velocity.
2.5 Properties of Compacts, 3.2.6
1105 gas classification, n—the separation of powder into
2.6 Forging, 3.2.7
particle size fractions by means of a gas stream of controlled
2.7 Metal Injection Molding, 3.2.8
velocity.
3. Sintering:
1106 chemical deposition, n—the precipitation of one metal
3.1 Process for Sintering, 3.3.1
from a solution of its salts by the addition of another metal or
3.2 Conditions During Sintering, 3.3.2
reagent to the solution.
3.3 Phenomena Resulting from Sintering, 3.3.3
1107 chemically precipitated metal powder, n—powder
3.4 Properties of Sintered Parts, 3.3.4
produced by the reduction of a metal from a solution of its salts
either by the addition of another metal higher in the electro-
This terminology is under the jurisdiction of ASTM Committee B-9 on Metal
motive series or by other reducing agent.
Powders and Metal Powder Productsand is the direct responsibility of Subcommit-
tee B09.01 on Nomenclature and Technical Data. 1108 reduced metal powder, n—metal powder produced,
Current edition approved October 10, 2000. Published December 2000. Origi-
without melting, by the chemical reduction of metal oxides or
nally published as B 243 – 49 T. Last previous edition B 243 –00.
other compounds.
Annual Book of ASTM Standards, Vol 02.05.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
B 243
1109 disintegration, n—the reduction of massive material 3.1.5 Shapes of Powder Particles:
to powder. 1301 acicular powder, n—needle-shaped particles.
1110 milling, n—the mechanical treatment of metal powder, 1302 needles, n—elongated rod-like particles.
or metal powder mixtures, as in a ball mill, to alter the size or
1303 granular powder, n—particles having approximately
shape of the individual particles or to coat one component of equidimensional nonspherical shapes.
the mixture with another.
1304 nodular powder, n—irregular particles having knot-
1111 pulverization, n—the reduction in particle size of
ted, rounded, or similar shapes.
metal powder by mechanical means, a specific type of disin-
1305 irregular powder, n—particles lacking symmetry.
tegration.
1306 spherical powder, n—globular-shaped particles.
3.1.4 Types of Powder:
1307 flake powder, n—flat or scale-like particles whose
1201 atomized metal powder, n—metal powder produced
thickness is small compared with the other dimensions.
by the dispersion of a molten metal by a rapidly moving gas, or
1308 plates, n—flat particles of metal powder having
liquid stream, or by mechanical dispersion.
considerable thickness.
1202 electrolytic powder, n—powder produced by electro-
3.1.6 Additives to Powder:
lytic deposition or by the pulverization of an electrodeposit.
1401 binder, n—a cementing medium; either a material
1203 dendritic powder, n—particles, usually of electrolytic
added to the powder to increase the green strength of the
origin, having the typical pine tree structure.
compact, and which is expelled during sintering; or a material
1204 carbonyl powder, n—a metal powder prepared by the (usually of relatively lower melting point) added to a powder
thermal decomposition of a metal carbonyl.
mixture for the specific purpose of cementing together powder
1205 master-alloy powder, n—a powder with high alloy particles which alone would not sinter into a strong body.
concentration, designed to be diluted when mixed with a base 1402 feedstock, n—in metal injection molding (MIM),a
powder to produce the desired composition.
moldable mixture of metal powder and binder.
1206 pre-alloyed powder, n—powder composed of two or 1403 powder lubricant, n—an agent mixed with or incor-
more elements that are alloyed in the powder manufacturing porated in a powder to facilitate the pressing and ejecting of the
process in which the particles are of the same nominal compact.
composition throughout. Synonymous with completely al- 1404 dispersion-strengthened material, n—a material
loyed powder.
consisting of a metal and finely dispersed, substantially in-
1207 completely alloyed powder, n—see pre-alloyed pow- soluble, metallic or nonmetallic phase.
der. 1405 pore-forming material, n—a substance included in a
1208 partially alloyed powder, n—a powder in which the powder mixture that volatilizes during sintering and thereby
alloy addition or additions are metallurgically bonded to an produces a desired kind and degree of porosity in the finished
elemental or pre-alloyed powder.
compact.
1209 diffusion-alloyed powder, n—a partially alloyed pow- 3.1.7 Treatment of Powder:
der produced by means of a diffusion anneal. 1501 blending, n—the thorough intermingling of powders
1210 mechanically alloyed powder, n—a composite pow- of the same nominal composition (not to be confused with
der produced by mechanically incorporating other constituents mixing).
which are generally insoluble within the deformable particles 1502 equalizing, n—see blending.
of the matrix metal.
1503 mixing, n—the thorough intermingling of powders of
1211 matrix metal, n—the continuous phase of a polyphase two or more materials.
alloy or mechanical mixture; the physically continuous metal- 1504 cross-product contamination, n—the unintentional
lic constituent in which separate particles of another constitu-
mixing of powders with distinct differences in either physical
ent are embedded. characteristics or chemical composition or both.
1212 composite powder, n—a powder in which each 1505 lubricating, n—mixing with, or incorporating in, a
particle consists of two or more distinct constituents.
powder, some agent to facilitate pressing and ejecting the
1213 spongy, n—a porous condition in metal powder compact from the die body; applying a lubricant to the die
particles usually observed in reduced oxides. walls and punch surfaces.
3.1.8 Properties of Powder:
1214 sponge iron, n—a coherent, porous mass of substan-
tially pure iron produced by solid-state reduction of iron oxide 1601 apparent density, n—the mass of a unit volume of
(for example, iron ore or mill scale).
powder, usually expressed as grams per cubic centimetre,
1215 sponge iron powder, n—ground and sized sponge determined by a specified method.
iron, which may have been purified or annealed or both. 1602 bulk density, n—the mass per unit volume of a
1216 mixed powder, n—a powder made by mixing two or powder under nonstandard conditions, for example, in a
more powders as uniformly as possible. The constituent shipping container (not to be confused with apparent density).
powders will differ in chemical composition or in particle size 1603 tap density, n—the apparent density of the powder in
or shape, or a combination thereof. a container that has been tapped under specified conditions.
1217 premix, n—a uniform mixture of ingredients to a 1604 flow rate, n—the time required for a powder sample of
prescribed analysis, prepared by the powder producer, for standard weight to flow through an orifice in a standard
direct use in compacting powder metallurgy products. instrument according to a specified procedure.
B 243
1605 specific surface, n—the surface area of one gram of series of standard sieves of decreasing size and the percentage
powder, usually expressed in square centimetres. passed by the sieve of finest size. Synonymous with screen
1606 compactibility, n—a conceptual term, encompassing analysis.
the powder characteristics of compressibility, green strength, 1702 screen analysis, n—see sieve analysis.
edge retention, and lamination tendency, that relates to the
1703 sieve classification, n—the separation of powder into
ability of a powder to be consolidated into a usable green particle size ranges by the use of a series of graded sieves.
compact.
3.1.10 Equipment to Evaluate Powder:
1607 compressibility, n—the capacity of a metal powder to 1801 powder flow meter, n—an instrument for measuring
be densified under a uniaxially applied pressure in a closed die.
the rate of flow of a powder according to a specified procedure.
3.2 Forming—Terms associated with consolidation of metal
DISCUSSION—Compressibility is measured in accordance with Test
powders and mixes, including tooling, equipment, and charac-
Method B 331 and may be expressed numerically as the pressure to
terization of sintered compacts.
reach a specified density, or alternatively the density at a given
pressure. 3.2.1 General:
2001 green—unsintered (not sintered); for example, green
1608 compression ratio, n—the ratio of the volume of the
compact, green density, green strength.
loose powder to the volume of the compact made from it.
2002 preforming—the initial pressing of a metal powder to
Synonymous with fill ratio.
form a compact that is subjected to a subsequent pressing
1609 fill ratio, n—see compression ratio.
operation other than coining or sizing. Also, the preliminary
1610 oversize powder, n—particles coarser than the maxi-
shaping of a refractory metal compact after presintering and
mum permitted by a given particle size specification.
before the final sintering.
1611 plus sieve, n—the portion of a powder sample retained
2003 blank, n—a pressed, presintered, or fully sintered
on a standard sieve of specified number. (See minus sieve.)
compact, usually in the unfinished condition, requiring cutting,
1612 minus sieve, n—the portion of a powder sample which
machining, or some other operation to give it its final shape.
passes through a standard sieve of specified number. (See plus
2004 briquet, n—see compact.
sieve.)
2005 compact, n—an object produced by the compression
1613 fines, n—the portion of a powder composed of
of metal powder, generally while confined in a die, with or
particles which are smaller than a specified size, currently less
without the inclusion of nonmetallic constituents. Synonymous
than 44 μm. See also superfines.
with briquet.
1614 superfines, n—the portion of a powder composed of
2006 pressed bar, n—a compact in the form of a bar; a
particles that are smaller than a specified size, currently less
green compact.
than 10 μm.
2007 rolled compact, n—a compact made by passing metal
1615 fraction, n—that portion of a powder sample that lies
powder continuously through a rolling mill so as to form
between two stated particle sizes. Synonymous with cut.
relatively long sheets of pressed material.
1616 cut, n—see fraction.
2008 composite compact, n—a metal powder compact
1617 subsieve fraction, n—particles all of which will pass
consisting of two or more adhering layers, rings, or other
through a 44-μm (No. 325) standard sieve.
shapes of different metals or alloys with each material retaining
1618 sieve fraction, n—that portion of a powder sample that
its original identity.
passes through a standard sieve of specified number and is
2009 compound compact, n—a metal powder compact
retained by some finer sieve of specified number.
consisting of mixed metals, the particles of which are joined by
1619 particle size, n—the controlling lineal dimension of an
pressing or sintering or both, with each metal particle retaining
individual particle as determined by analysis with sieves or
substantially its original composition.
other suitable means.
3.2.2 Processes for Compacting:
1620 particle size distribution, n—the percentage by
2101 molding, v—the pressing of powder to form a com-
weight, or by number, of each fraction into which a powder
pact.
sample has been classified with respect to sieve number or
2102 press, v—to apply force to a mass of powder, generally
microns. (Preferred usage: “particle size distribution by fre-
while confined in a die or container, to form a compact.
quency.”)
2103 double press-double sinter, n—to repress and sinter a
1621 hydrogen loss, n—the loss in weight of metal powder
previously presintered or sintered compact.
or of a compact caused by heating a representative sample for
a specified time and temperature in a purified hydrogen
DISCUSSION—Used to describe a four-step manufacturing process.
atmosphere—broadly, a measure of the oxygen content of the
2104 single-action pressing, n—a method by which a
sample when applied to materials containing only s
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