1、Designation: B330 15Standard Test Methods forEstimating Average Particle Size of Metal Powders andRelated Compounds Using Air Permeability1This standard is issued under the fixed designation B330; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、 of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 These
3、 test methods use air permeability to determine anenvelope-specific surface area and its associated averageequivalent spherical diameter (from 0.2 to 75m) of metalpowders and related compounds. The powders may be ana-lyzed in their “as-supplied” (shipped, received, or processed)condition or after th
4、ey have been de-agglomerated or milled bya laboratory procedure (“lab milled”) such as that specified inPractice B859. The values obtained are not intended to beabsolute but are generally useful on a relative basis for controlpurposes.1.2 UnitsWith the exception of the values for density andthe mass
5、 used to determine density, for which the use of thegram per cubic centimetre (g/cm3) and gram (g) units is thelongstanding industry practice; and the units for pressure, cmH2O - also long-standing practice; the values in SI units are tobe regarded as standard.1.3 This standard does not purport to a
6、ddress all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B243 Termin
7、ology of Powder MetallurgyB859 Practice for De-Agglomeration of Refractory MetalPowders and Their Compounds Prior to Particle SizeAnalysisE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE456 Terminology Relating to Quality and StatisticsE691 Practice
8、 for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO/DIS Document:3ISO/DIS 10070 Metallic Powders: Determinations ofEnvelope-Specific Surface Area from Measurements ofthe Permeability to Air of a Powder Bed Under Steady-State Flow Conditions3. Terminology3.1 Def
9、initions Many terms used in this test method aredefined in Terminology B243.3.2 Definitions of Terms Specific to This Standard:3.2.1 MIC Sub-sieve AutoSizer (MIC SAS), na commer-cially available permeability instrument for measuring enve-lopespecific surface area and estimating average particle size
10、from 0.2 to 75m.3.2.2 Fisher Sub-Sieve Sizer (FSSS), na commerciallyavailable permeability instrument for measuring envelope-specific surface area and estimating average particle size(Fisher Number) from 0.5 to 50 m.3.2.3 envelope-specific surface area, n specific surfacearea of a powder as determin
11、ed by gas permeametry inaccordance with ISO/DIS 10070.3.2.4 air permeability, nmeasurement of air pressure dropacross a packed bed of powder.3.2.5 de-agglomeration, nprocess used to break up ag-glomerates of particles.3.2.6 Fisher Number, ncalculated value equated to anaverage particle diameter, ass
12、uming all the particles are spheri-cal and of uniform size.3.2.7 Fisher calibrator tube, njewel with a precisionorifice mounted in a tube similar to a sample tube. Thecalibrator tube value is directly traceable to the master tubemaintained by ASTM International Subcommittee B09.03 onRefractory Metal
13、 Powders1These test methods are under the jurisdiction of ASTM Committee B09 onMetal Powders and Metal Powder Products and are the direct responsibility ofSubcommittee B09.03 on Refractory Metal Powders.Current edition approved Oct. 1, 2015. Published October 2015. Originallyapproved in 1958. Last p
14、revious edition approved in 2012 as B330 -12. DOI:10.1520/B0330-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM we
15、bsite.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Un
16、ited States13.2.8 porosity of a bed of powder, nratio of the volume ofthe void space in the powder bed to the that of the overallvolume of the powder bed.3.2.9 agglomerate, nseveral particles adhering together.3.2.10 average particle size, n(for the purposes of thesetest methods only) an estimate of
17、 the equivalent averagespherical particle diameter, calculated from the measuredenvelope-specific surface area, assuming that all the powderparticles are spherical and that all are exactly the same size.4. Significance and Use4.1 These test methods provide procedures for determiningthe envelope-spec
18、ific surface area of powders, from which iscalculated an “average” particle diameter, assuming the par-ticles are monosize, smooth surface, nonporous, sphericalparticles. For this reason, values obtained by these test methodswill be reported as an average particle size or Fisher Number.The degree of
19、 correlation between the results of these testmethods and the quality of powders in use will vary with eachparticular application and has not been fully determined.4.2 These test methods are generally applicable to all metalpowders and related compounds, including carbides, nitrides,and oxides, for
20、particles having diameters between 0.2 and 75m (MIC SAS) or between 0.5 and 50 m (FSSS). They shouldnot be used for powders composed of particles whose shape istoo far from equiaxed - that is, flakes or fibers. In these cases,it is permissible to use the test methods described only byagreement betwe
21、en the parties concerned. These test methodsshall not be used for mixtures of different powders, nor forpowders containing binders or lubricants. When the powdercontains agglomerates, the measured surface area may beaffected by the degree of agglomeration. Methods of de-agglomeration such as that sp
22、ecified in Practice B859 may beused if agreed upon between the parties concerned.4.3 When an “average” particle size of powders is deter-mined either the MIC SAS or the FSSS, it should be clearlykept in mind that this average size is derived from thedetermination of the specific surface area of the
23、powder usinga relationship that is true only for powders of uniform size andspherical shape. Thus, the results of these methods are onlyestimates of average particle size.5. Apparatus5.1 MIC Sub-sieve AutoSizer (MIC SAS)4Method 1consisting of an air pump, a calibrated gas mass flowcontroller, a prec
24、ision-bore sample tube, a sample tube retain-ing collar, a spacer tool, a gas flow metering valve, twoprecision pressure transducers (inlet and outlet), a steppermotor controlled ballscrew-mounted piston, and computerhardware and software for instrument control and calculationand reporting of result
25、s. Included is accessory equipmentconsisting of a plug manipulator (extraction rod), two porousplugs, and a supply of paper disks.NOTE 1When homing the piston, adjust the sample packing assembly(1) as described in the manufacturers directions, with the plugs and paperdisks stacked together and place
26、d on the fixed anvil spigot, or (2) using aspecially designed baseline (homing) gauge instead of the plugs and paperdisks. This baseline gauge shall have a height of 20.30 6 0.10 mm. Checkall plug heights when new plugs are purchased and periodically thereafterto make sure all are equal in height.5.
27、1.1 Powder funnelstainless steel, with spout outsidediameter slightly smaller than the sample tube inside diameter.5.1.2 The manufacturer provides instructions which shouldbe followed, using the “Inorganics Test” procedure whentesting metal powders and related compounds. Particular atten-tion should
28、 be given to proper maintenance of the instrumentwith special reference to the instructions on (1) “homing” thepiston when turning on from an unpowered state, (2) setting thepressure and periodic checking of the pressure, (3) condition ofO-rings on the piston and sample spigot, and (4) the samplepac
29、king assembly (plugs and paper disks).5.2 Fisher Sub-Sieve Sizer (FSSS)5 Method 2consistingof an air pump, an air-pressure regulating device, a precision-bore sample tube, a standardized double-range air flowmeter,and a calculator chart. Included is accessory equipment con-sisting of a plug manipula
30、tor, powder funnel, two porous plugs,a supply of paper disks, and a rubber tube support stand.NOTE 2Necessary replacement parts should be obtained from themanufacturer, especially in the case of the precision manometer which isa part of the air flowmeter.5.2.1 The manufacturer has also furnished ins
31、tructionswhich should be followed except as amended as follows.Particular attention should be given to proper maintenance ofthe instrument with special reference to the instructions on (1)periodic checking of the water level in the pressure regulatorstandpipe, (2) manometer level before the sample t
32、ube isinserted, and (3) the sample packing assembly.5.2.2 Jewel Calibrator Tube6a tube to be used as astandard for average particle size measurement. It allowsoperators to relate their data to that of other analysts. Eachcalibrator has been factory tested three times with the resultingreadings and a
33、ssociated porosity recorded on the tube.NOTE 3Adjust the sample packing assembly (1) as described in themanufacturers instructions with the exception that the plugs and paperdisks are not inserted in the sample tube, but are merely stacked togetherand placed between the brass support and the “flat”
34、of the bottom of therack, and (2) as previously described except that a specially made baselinegauge is used instead of the plugs and paper disks. This baseline gaugeshall have a height of 19.30 6 0.10 mm. Check all plug heights when newplugs are purchased and periodically thereafter to make sure al
35、l are equalin height.4The sole source of supply of the MIC Sub-sieve AutoSizer (MIC SAS) knownto the committee is Micromeritics Instrument Corporation, Particulate Systems,4356 Communications Drive, Norcross, GA 30093-2901, USA. If you are aware ofalternative suppliers, please provide this informati
36、on to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.5The Fisher Sub-Sieve Sizer (FSSS) is no longer commercially available, nor isit supported with parts and service. It is included here as ap
37、paratus for Method 2because of several instruments still operating in the field. In-house repair or partsreplacement is discouraged, as these are likely to detrimentally affect results andprecision.6The Jewel Calibrator Tube is no longer commercially available. A “Master”Jewel Calibrator Tube is mai
38、ntained by ASTM International Subcommittee B09.03for calibration and traceability of currently existing in-house calibrator tubes.B330 1525.3 Balancehaving a capacity of at least 50 g and asensitivity of 0.001 g.6. Standardization of Apparatus6.1 Method 1 MIC Sub-sieve AutoSizer (MIC SAS):6.1.1 Befo
39、re proceeding with standardization of the MICSAS, the following items shall be checked:6.1.1.1 The sample tube and plugs shall not be worn to thepoint where results are affected.6.1.1.2 Inspect the O-ring seals for tears and abrasionmarks. The O-ring seals shall not be worn to the point wherethe sam
40、ple tube moves easily by hand or the pressure readingvaries as the sample tube is moved.6.1.1.3 The drying agent shall be in proper condition.6.1.2 Whenever the instrument is turned on from an unpow-ered state, the piston shall be “homed” according to themanufacturers instructions. See Note 1 above.
41、6.1.3 Before running the initial sample, the pressure shall beset to 50.0 (+0.1, -0.5) cm H2O, using the metering valve; thenchecked and reset if necessary every few hours, or if theambient temperature changes more than 62C.NOTE 4The metering valve position should not be adjusted for repeatruns of t
42、he same sample as this will likely lead to a loss of precision evenif the inlet pressure reading has drifted a little outside the 50.0 (+0.1, -0.5)cm H2O range. Further adjustment is not necessary as the pressure iscontrolled precisely during the particle size measurement.6.1.4 Standardization is re
43、commended before and after anyseries of determinations or at least every 4 hours of continuedoperation. Warm-up of the instrument is required if it has beenoff for more than 30 minutes.6.1.5 Calibration of the pressure transducers is recom-mended every 3-6 months, using a traceable external pressure
44、gauge per the manufacturers instructions.6.2 Method 2 Fisher Sub-Sieve Sizer (FSSS):6.2.1 Before proceeding with standardization of the FSSS,the following items shall be checked:6.2.1.1 The chart shall be properly aligned horizontally withthe indicator pointer.6.2.1.2 The rack and pinion shall be pr
45、operly alignedvertically with the chart.6.2.1.3 The sample tube or plugs shall not be worn to thepoint where results are affected.6.2.1.4 The manometer and air resistors shall be free ofvisible contamination.6.2.1.5 The rubber sample tube seals shall not be worn tothe point where leakage occurs.6.2.
46、1.6 The sample packing post shall be properly adjusted.6.2.1.7 The drying agent shall be in proper condition.6.2.1.8 The manometer and standpipe levels shall bechecked.6.2.1.9 Adjust the manometer only when the machine is notoperating and with the pressure released for minimum of 5 minto allow the m
47、anometer tube to drain completely.6.2.2 The standardization of the Fisher Sub-Sieve Sizershall be made using the Fisher jewel calibrator tube (jewelorifice tube) as the primary standard. Specification shall bemade at both ranges of the machine. The Fisher jewel calibratortube used for standardizatio
48、n shall be checked under a micro-scope at least once a month to determine the condition andcleanliness of the orifice. If the orifice is not clean, clean asdescribed in the Fisher sub-sieve sizer instruction manual.6.2.3 With the sub-sieve sizer properly adjusted and set tothe proper range, proceed
49、as follows:6.2.3.1 Mount the Fisher jewel calibrator tube between therubber seal supports just to the right of the brass post. Clampthe upper cap down onto the tube so that an airtight seal isobtained at both ends.6.2.3.2 Adjust the calculator chart so that the porosityreading corresponds to the value indicated on the jewelcalibrator tube.6.2.3.3 Switch on the instrument and allow it to warm up fora minimum of 20 minutes. Adjust the pressure-control knob,located near the bubble observation window at the lower left ofthe panel, until the bubbles
