1、Designation: B 330 07Standard Test Method forFisher Number of Metal Powders and Related Compounds1This standard is issued under the fixed designation B 330; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 A number in parentheses indicates the year of last reapproval. Asuperscript 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.1. Scope1.1 This test method uses air permeability to determin
3、e anenvelope-specific surface area and its associated averageequivalent spherical diameter (from 0.5 to 50 m) of metalpowders and related compounds. The powders may be ana-lyzed in their “as-supplied” (shipped, received, or processed)condition or after they have been de-agglomerated or milled bya la
4、boratory procedure (“lab milled”) such as that specified inPractice B 859. The values obtained are not intended to beabsolute but are generally useful on a relative basis for controlpurposes.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
5、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:2B 243 Terminology of Powder MetallurgyB 859 Practice for De-Agglomeration of Refr
6、actory MetalPowders and Their Compounds Prior to Particle SizeAnalysisE 456 Terminology Relating to Quality and StatisticsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO/DIS Document:3ISO/DIS 10070 Metallic Powders: Determinations ofEnvelope-S
7、pecific Surface Area from Measurements ofthe Permeability to Air of a Powder Bed Under Steady-State Flow Conditions3. Terminology3.1 DefinitionsMany terms used in this test method aredefined in Terminology B 243.3.2 Definitions of Terms Specific to This Standard:3.2.1 Fisher sub-sieve sizer, na comm
8、ercially availablepermeability instrument for measuring envelope-specific sur-face area.3.2.2 envelope-specific surface area, nspecific surfacearea of a powder as determined by gas permeametry inaccordance with ISO/DIS 10070.3.2.3 air permeability, nmeasurement of air pressure dropacross a packed be
9、d of powder.3.2.4 de-agglomeration, nprocess used to break up ag-glomerates of particles.3.2.5 Fisher Number, ncalculated value equated to anaverage particle diameter, assuming all the particles are spheri-cal and of uniform size.3.2.6 Fisher calibrator tube, njewel with a precisionorifice mounted i
10、n a tube similar to a sample tube. Thecalibrator tube value is directly traceable to the master tubemaintained by Fisher.3.2.7 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.3.2.8 agglomerate, nseveral particles
11、 adhering together.4. Significance and Use4.1 This test method provides a procedure for determiningthe envelope-specific surface area of powders, from which iscalculated an “average” particle diameter, assuming the par-ticles are monosize, smooth surface, nonporous, sphericalparticles. For this reas
12、on, values obtained by this test methodwill be defined as a Fisher Number. The degree of correlationbetween the results of this test method and the quality ofpowders in use will vary with each particular application andhas not been fully determined.4.2 This test method is generally applicable to all
13、 metalpowders and related compounds, including carbides, nitrides,and oxides, for particles having diameters between 0.5 and 50m. It should not be used for powders composed of particleswhose shape is too far from equiaxed, that is, flakes or fibers.In these cases, it is permissible to use the test m
14、ethod described1This test method is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.03 on Refractory Metal Powders.Current edition approved March 15, 2007. Published April 2007. Originallyapproved in 1958. L
15、ast previous edition approved in 2005 as B 330 05.2For 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 website.3Available
16、from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.only by agreement between the parties concerned. This testmethod shal
17、l not be used for mixtures of different powders norfor powders 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 referenced in 1.1 may be used ifagreed upon between
18、 the parties concerned.4.3 When an “average” particle size of powders is deter-mined using the Fisher sub-sieve sizer, it should be clearly keptin mind that this average size is derived from the determinationof the specific surface area of the powder using a relationshipthat is true only for powders
19、 of uniform size and sphericalshape.5. Apparatus5.1 The Fisher sub-sieve sizer4consists of an air pump, anair-pressure regulating device, a precision-bore sample tube, astandardized double-range air flowmeter, and a calculatorchart. Included is accessory equipment consisting of a plugmanipulator, po
20、wder funnel, two porous plugs, a supply ofpaper disks, and a rubber tube support stand.NOTE 1Necessary replacement parts should be obtained from themanufacturer, especially in the case of the precision manometer which isa part of the air flowmeter.5.2 The manufacturer also furnishes directions which
21、should be followed except as amended as follows. Particularattention should be given to proper maintenance of the instru-ment with special reference to the instructions on (1) periodicchecking of the water level in the pressure regulator standpipe,(2) manometer level before the sample tube is insert
22、ed, and (3)the sample packing assembly.5.3 Jewel Calibrator Tubea standard for average particlesize measurement. It allows operators to relate their data to thatof other analysts. Each calibrator is factory tested three timeswith the resulting readings and associated porosity recorded onthe tube.NOT
23、E 2Adjust the sample packing assembly (1) as described in themanufacturers directions 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” of the bottom of therack, and (2) as previous
24、ly 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 all are equalin height.5.4 Balancehaving a capa
25、city of at least 50 g and asensitivity of 0.001 g.6. Standardization of Apparatus6.1 Before proceeding with standardization of the Fishersub-sieve sizer, the following items shall be checked:6.1.1 The chart shall be properly aligned horizontally withthe indicator pointer.6.1.2 The rack and pinion sh
26、all be properly aligned verti-cally with the chart.6.1.3 The sample tube or plugs shall not be worn.6.1.4 The manometer and air resistors shall be free of visiblecontamination.6.1.5 The rubber sample tube seals shall not be worn to thepoint where leakage occurs.6.1.6 The sample packing post shall be
27、 properly adjusted.6.1.7 The drying agent shall be in proper condition.6.1.8 The manometer and standpipe levels shall be checked.6.1.8.1 Adjust the manometer only when the machine is notoperating and with the pressure released for minimum of 5 minto allow the manometer tube to drain completely.6.2 T
28、he standardization of the Fisher sub-sieve sizer shall bemade using the Fisher jewel calibrator tube (jewel orifice tube)as the primary standard. Specification shall be made at bothranges of the machine.The Fisher jewel calibrator tube used for standardizationshall be checked under a microscope at l
29、east once a month todetermine the condition and cleanliness of the orifice.If the orifice is not clean, clean as described in the Fishersub-sieve sizer instruction manual.6.3 With the sub-sieve sizer properly adjusted and set to theproper range, proceed as follows:6.3.1 Mount the Fisher jewel calibr
30、ator 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.6.3.2 Adjust the calculator chart so that the porosity readingcorresponds to the value indicated on the jewel calibrator tube.6.3.3 Sw
31、itch on the machine and allow it to warm up for aminimum of 20 min. Adjust the pressure-control knob, locatednear the bubble observation window at the lower left of thepanel, until the bubbles rise in the standpipe at the rate of twoto three bubbles per second. This will cause the water line torise
32、above the calibration mark on the upper end of thestandpipe. This is normal and does not mean the calibration isin error.6.3.4 The liquid level in the manometer tube will rise slowlyuntil it reaches a maximum. Allow at least 5 min for this tohappen. At the end of this period, using care not to distu
33、rb thechart, turn the rack up until the upper edge of the crossbarcoincides with the bottom of the liquid meniscus in themanometer. The Fisher Number is indicated by the location ofthe pointer tip in relation to the curves on the calculator chart.Record the ambient temperature to the nearest 1C. Rel
34、ease theclamp on the upper end of the tube slowly so the manometerreturns to its zero position slowly with very little overshoot.This limits the formation of liquid droplets on the inside of themanometer tube.6.3.5 The value obtained in this manner must correspond tothe Fisher Number indicated on th
35、e jewel calibrator tube within61%.6.3.6 If the Fisher Number value as indicated on the chartdoes not correspond to 61% of the value indicated on the jewelcalibrator tube, calibrate the sub-sieve as follows:Adjust either4The sole source of supply of the Fisher sub-sieve sizer #14-311A known to thecom
36、mittee at this time is Fisher Scientific, Instrument Division, 2000 Park Lane,Pittsburgh, PA 15275. Besides supplying the basic instrument, they also supplyaccessories of: calibrator tube #14-313-7 and sample calibrator, #14-311-2. If youare aware of alternative suppliers, please provide this inform
37、ation to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.B330072the high needle valve or the low needle valve as required tobring the Fisher number indicated on the chart to the valueindicated o
38、n the jewel calibrator tube. After adjustment ismade, repeat 6.3.4.6.3.7 Because only one flowmeter is used for the low (0.5-to 15.0-m) Fisher Number range while both flowmeters areused for the high (15.0- to 50.0-m) Fisher Number range, thelow range should be standardized first. After the low range
39、 isstandardized, the high range is then standardized, makingadjustments only to the one flowmeter opened up by therange-control knob.6.3.8 Standardization with the jewel calibrator tube is rec-ommended before and after any series of determinations or atleast every4hofcontinued operation. Warm-up of
40、themachine is required if it has been off for more than 30 min.7. Procedure7.1 Temperature of TestMake Fisher Number determina-tions with 62C of the temperature at which standardization ofthe Fisher sub-sieve sizer was made. Restandardize if thetemperature of the test varies more than 62C.7.2 Size o
41、f Test SampleThe mass of sample used for testsshould be equal in grams (within 60.01 g) to the theoreticaldensity of the powder (tungsten, 19.3 g; molybdenum, 10.22 g;tantalum, 16.6 g; and so forth).7.3 Fisher Number DeterminationThe Fisher Numberdetermination shall be made by the same operator who
42、makesthe standardizations and is started after standardization or thedetermination of another sample. Proceed as follows:7.3.1 With the sub-sieve sizer properly adjusted, set therange control to the range desired.7.3.2 Lay a paper disk over one end of the sample tube usingone of the porous plugs wit
43、h the perforated surface of the plugagainst the surface of the paper disk. This crimps the paperaround the edges and the paper precedes the plug into thesample tube. Push the plug into the tube until it is even with theend of the sample tube. Place the sample tube in a verticalposition in a support
44、with the paper side of the plug up.7.3.3 Determine the mass of the sample.7.3.4 With the aid of the powder funnel, completely transferthe sample into the sample tube, tapping the side of the tubeand funnel two or three times each to settle the powder. Lay asecond paper disk over the top of the sampl
45、e tube and, usinganother porous brass plug, force the plug and paper disk downinto the sample tube until it is just inside the sample tube. Placethe sample tube on the brass post beneath the rack and pinionwith the lower plug in contact with the upper end of the brasspost.7.3.5 Lower the rack, guidi
46、ng it until the flat-bottom endcomes in contact with the upper plug. Pack the sample firmlyby turning down the pinion knob with the torque wrench ortorque screwdriver until a compressive force of 222 N (50 lbf)is applied to the sample. After this force is applied, the sampletube should not be touchi
47、ng the block in which the brass postis mounted. In cases in which the tube tends to move down andrest on the block during compression, the tube can be heldtemporarily by hand or a spacer can be used until most of thecompressive force has been applied. The spacer is thenremoved when the maximum force
48、 is actually applied. Applyand release maximum force a total of three times. After thefinal maximum compression force has been applied, check therack to make sure it has not been removed upward with thefinal release of pressure. Check torque wrench or torquescrewdriver for standardization at least o
49、nce every month usingsample pressure calibrator or an equivalent device.7.3.6 Shift the calculator chart laterally until the extreme tipof the pointer just coincides with the sample-height curve onthe chart. The pointer should be midway between the top andbottom of the line. The chart must not be moved after thissetting until the determination is finished. Record the porosityvalue indicated at the bottom of the chart.7.3.7 Without disturbing the sample in any way, mount thesample tube between the rubber-cushioned supports just to theright of the brass post. Cl
