1、Designation: B 243 08aStandard Terminology ofPowder Metallurgy1This standard is issued under the fixed designation B 243; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates
2、the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This terminology standard includes definitions that arehelpful in the interpretation and application of powder metal-lurgy terms.2. Referenced Documents2.1 ASTM Standa
3、rds:B 331 Test Method for Compressibility of Metal Powders inUniaxial Compaction3. Terminology3.1 PowderTerms associated with production, character-ization, use, and testing of metal powders.3.1.1 Table of Contents1. Powders:1.0 General, 3.1.21.1 Processes to Produce Powder, 3.1.31.2 Types of Powder
4、, 3.1.41.3 Shapes of Powder Particles, 3.1.51.4 Additives to Powder, 3.1.61.5 Treatment of Powder, 3.1.71.6 Properties of Powder, 3.1.81.7 Procedures to Evaluate Powder, 3.1.91.8 Equipment to Evaluate Powder, 3.1.102. Forming:2.0 General, 3.2.12.1 Processes for Compacting, 3.2.22.2 Conditions of Com
5、pacting,2.3 Tools Used for Compacting, 3.2.32.4 Phenomena Resulting from Compaction, 3.2.42.5 Properties of Compacts, 3.2.62.6 Forging, 3.2.72.7 Metal Injection Molding, 3.2.83. Sintering:3.1 Process for Sintering, 3.3.13.2 Conditions During Sintering, 3.3.23.3 Phenomena Resulting from Sintering, 3.
6、3.33.4 Properties of Sintered Parts, 3.3.43.5 Procedure to Evaluate Sintered Parts, 3.3.53.6 Removal of Binders, 3.3.64. Postsinter Treatments:4.1 Processes, 3.4.15. Miscellaneous:5.1 Definitions, 3.5.15.2 Processes, 3.5.25.3 Materials, 3.5.33.1.2 General:agglomerate, nseveral particles adhering tog
7、ether.metal powder, nparticles of elemental metals or alloys,normally less than 1000 m (1 mm) in size.particulate matter, nsee powder.PM, nthe acronym for powder metallurgy.powder, nparticles that are usually less than 1000 m (1mm) in size.powder metallurgy, nthe production and utilization ofmetal p
8、owders.3.1.3 Processes to Produce Powder:air classification, nthe separation of powder into particlesize fractions by means of an air stream of controlled velocity.atomization, nthe dispersion of a molten metal intoparticles by a rapidly moving gas or liquid stream or bymechanical means.chemical dep
9、osition, nthe precipitation of one metal froma solution of its salts by the addition of another metal or reagentto the solution.chemically precipitated metal powder, npowder producedby the reduction of a metal from a solution of its salts either bythe addition of another metal higher in the electrom
10、otive seriesor by other reducing agent.1This terminology is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.01 on Nomenclature and Technical Data.Current edition approved March 15, 2008. Published May 2008.
11、Originallyapproved in 1949. Last previous edition approved in 2008 as B 243 08.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.classification, nseparation of a powder into fractionsaccording to particle size.disintegration, nthe redu
12、ction of massive material topowder.gas classification, nthe separation of powder into particlesize fractions by means of a gas stream of controlled velocity.granulation, nthe production of coarse metal particles bypouring the molten metal through a screen into water (shotting)or by violent agitation
13、 of the molten metal while solidifying.milling, nthe mechanical treatment of metal powder, ormetal powder mixtures, as in a ball mill, to alter the size orshape of the individual particles or to coat one component ofthe mixture with another.pulverization, nthe reduction in particle size of metalpowd
14、er by mechanical means, a specific type of disintegration.reduced metal powder, nmetal powder produced, withoutmelting, by the chemical reduction of metal oxides or othercompounds.3.1.4 Types of Powder:atomized metal powder, nmetal powder produced by thedispersion of a molten metal by a rapidly movi
15、ng gas, or liquidstream, or by mechanical dispersion.carbonyl powder, na metal powder prepared by the ther-mal decomposition of a metal minuted powder, na powder produced by mechanicalattrition of solid metal or pletely alloyed powder, nsee pre-alloyed posite powder, na powder in which each particle
16、consists of two or more distinct constituents.dendritic powder, nparticles, usually of electrolytic origin,having the typical pine tree structure.diffusion-alloyed powder, na partially alloyed powderproduced by means of a diffusion anneal.electrolytic powder, npowder produced by electrolyticdepositi
17、on or by the pulverization of an electrodeposit.hydrogen-reduced powder, npowder produced by the re-duction of a metal oxide in an atmosphere containing hydro-gen.master-alloy powder, na powder with high alloy concen-tration, designed to be diluted when mixed with a base powderto produce the desired
18、 composition.matrix metal, nthe continuous phase of a polyphase alloyor mechanical mixture; the physically continuous metallicconstituent in which separate particles of another constituentare embedded.mechanically alloyed powder, na composite powder pro-duced by mechanically incorporating other cons
19、tituents whichare generally insoluble within the deformable particles of thematrix metal.mixed powder, na powder made by mixing two or morepowders as uniformly as possible. The constituent powderswill differ in chemical composition or in particle size or shape,or a combination thereof.nanopowder, na
20、 powder consisting of particles typicallyless than 100 nm in size.partially alloyed powder, na powder in which the alloyaddition or additions are metallurgically bonded to an elemen-tal or pre-alloyed powder.pre-alloyed powder, npowder composed of two or moreelements that are alloyed in the powder m
21、anufacturing processin which the particles are of the same nominal compositionthroughout. Synonymous with completely alloyed powder.premix, na uniform mixture of ingredients to a prescribedanalysis, prepared by the powder producer, for direct use incompacting powder metallurgy products.sponge iron,
22、na coherent, porous mass of substantiallypure iron produced by solid-state reduction of iron oxide (forexample, iron ore or mill scale).sponge iron powder, nground and sized sponge iron,which may have been purified or annealed or both.spongy, na porous condition in metal powder particlesusually obse
23、rved in reduced oxides.3.1.5 Shapes of Powder Particles:acicular powder, nneedle-shaped particles.flake powder, nflat or scale-like particles whose thicknessis small compared with the other dimensions.granular powder, nparticles having approximately equidi-mensional nonspherical shapes.irregular pow
24、der, nparticles lacking symmetry.needles, nelongated rod-like particles.nodular powder, nirregular particles having knotted,rounded, or similar shapes.platelet powder, na powder composed of flat particleshaving considerable thickness (as compared with flake pow-der).plates, nflat particles of metal
25、powder having considerablethickness.spherical powder, nglobular-shaped particles.3.1.6 Additives to Powder:binder, na cementing medium; either a material added tothe powder to increase the green strength of the compact, andwhich is expelled during sintering; or a material (usually ofrelatively lower
26、 melting point) added to a powder mixture forthe specific purpose of cementing together powder particleswhich alone would not sinter into a strong body.dispersion-strengthened material, na material consistingof a metal and finely dispersed, substantially insoluble, metallicor nonmetallic phase.feeds
27、tock, nin metal injection molding (MIM), a moldablemixture of metal powder and binder.lubricantmaterial used to reduce inter-particle friction andthe friction between the powder mass and the tooling.lubricant (admixed), na lubricant incorporated into apowder mixture.lubricant (die-wall), na lubrican
28、t applied to the toolingsurfaces to facilitate ease of movement of the tooling and theremoval of the compact or part from the tooling.pore-forming material, na substance included in a powdermixture that volatilizes during sintering and thereby producesa desired kind and degree of porosity in the fin
29、ished compact.3.1.7 Treatment of Powder:blending, nthe thorough intermingling of powders of thesame nominal composition (not to be confused with mixing).B 243 08a2cross-product contamination, nthe unintentional mixingof powders with distinct differences in either physical charac-teristics or chemica
30、l composition or both.equalizing, nsee blending.mixing, nthe thorough intermingling of powders of two ormore materials.3.1.8 Properties of Powder:angle of repose, nthe basal angle of a pile formed bypowder when freely poured under specified conditions onto ahorizontal surface.apparent density, nthe
31、mass of a unit volume of powder,usually expressed as grams per cubic centimetre, determinedby a specified method.bulk density, nthe mass per unit volume of a powder undernonstandard conditions, for example, in a shipping container(not to be confused with apparent density).compactibility, na conceptu
32、al term, encompassing thepowder characteristics of compressibility, green strength, edgeretention, and lamination tendency, that relates to the ability ofa powder to be consolidated into a usable green pressibility, nthe capacity of a metal powder to bedensified under a uniaxially applied pressure i
33、n a closed die.DISCUSSIONCompressibility is measured in accordance with TestMethod B 331 and may be expressed numerically as the pressure toreach a specified density, or alternatively the density at a givenpressure.2compression ratio, nthe ratio of the volume of the loosepowder to the volume of the
34、compact made from it. Synony-mous with fill ratio.cut, nsee fraction.fill ratio, nsee compression ratio.fines, nthe portion of a powder composed of particleswhich are smaller than a specified size, currently less than 44m. See also superfines.flow rate, nthe time required for a powder sample ofstand
35、ard weight to flow through an orifice in a standardinstrument according to a specified procedure.fraction, nthe portion of a powder sample that liesbetween two stated particle sizes. Synonymous with cut.hydrogen loss, nthe loss in weight of metal powder or ofa compact caused by heating a representat
36、ive sample for aspecified time and temperature in a purified hydrogenatmospherebroadly, a measure of the oxygen content of thesample when applied to materials containing only such oxidesas are reducible with hydrogen and no hydride-forming ele-ment.minus sieve, nthe portion of a powder sample whichp
37、asses through a standard sieve of specified number. (See plussieve.)oversize powder, nparticles coarser than the maximumpermitted by a given particle size specification.particle size, nthe controlling lineal dimension of anindividual particle as determined by analysis with sieves orother suitable me
38、ans.particle size distribution, nthe percentage by weight, or bynumber, of each fraction into which a powder sample has beenclassified with respect to sieve number or microns. (Preferredusage: “particle size distribution by frequency.”)plus sieve, nthe portion of a powder sample retained on astandar
39、d sieve of specified number. (See minus sieve.)segregation, nthe separation of one or more constituentsof a powder, for example, by particle size or chemicalcomposition.sieve fraction, nthat portion of a powder sample thatpasses through a standard sieve of specified number and isretained by some fin
40、er sieve of specified number.specific surface, nthe surface area of one gram of powder,usually expressed in square centimetres.subsieve fraction, nthe portion of powder passing througha 45-m (no. 325) sieve.superfines, nthe portion of a powder composed of particlesthat are smaller than a specified s
41、ize, currently less than 10 m.tap density, nthe apparent density of the powder in acontainer that has been tapped under specified conditions.3.1.9 Procedures to Evaluate Powder:screen analysis, nsee sieve analysis.sieve analysis, nparticle size distribution; usually ex-pressed as the weight percenta
42、ge retained upon each of a seriesof standard sieves of decreasing size and the percentage passedby the sieve of finest size. Synonymous with screen analysis.sieve classification, nthe separation of powder into par-ticle size ranges by the use of a series of graded sieves.3.1.10 Equipment to Evaluate
43、 Powder:powder flow meter, nan instrument for measuring the rateof flow of a powder according to a specified procedure.3.2 FormingTerms associated with consolidation of metalpowders and mixes, including tooling, equipment, and charac-terization of sintered compacts.3.2.1 General:blank, na pressed, p
44、resintered, or fully sintered compact,usually in the unfinished condition, requiring cutting, machin-ing, or some other operation to give it its final shape.briquet, nsee pact, nan object produced by the compression ofmetal powder, generally while confined in a die, with orwithout the inclusion of n
45、onmetallic constituents. Synonymouswith posite compact, na metal powder compact consistingof two or more adhering layers, rings, or other shapes ofdifferent metals or alloys with each material retaining itsoriginal pound compact, na metal powder compact consistingof mixed metals, the particles of wh
46、ich are joined by pressingor sintering or both, with each metal particle retaining substan-tially its original composition.greenunsintered (not sintered); for example, green com-pact, green density, green strength.preformingthe initial pressing of a metal powder to form acompact that is subjected to
47、 a subsequent pressing operationother than coining or sizing.Also, the preliminary shaping of arefractory metal compact after presintering and before the finalsintering.2See Test Method B 331.B 243 08a3pressed bar, na compact in the form of a bar; a greencompact.rolled compact, na compact made by pa
48、ssing metalpowder continuously through a rolling mill so as to formrelatively long sheets of pressed material.3.2.2 Processes for Compacting:cold pressing, nthe forming of a compact at room tem-pacting, na process in which a powder held in a die orother container is subjected to an external force in
49、 order todensify the powder and produce a compact of prescribed shapeand pacting pressure (uniaxial), napplied force divided bythe projected area of contact with the punch(es).double-action pressing, na method by which a powder ispressed in a die between opposing moving punches.double press-double sinter, nto repress and sinter a previ-ously presintered or sintered compact.DIS
