ASTM B330-00
(Test Method)Standard Test Method for Fisher Number of Metal Powders and Related Compounds
Standard Test Method for Fisher Number of Metal Powders and Related Compounds
SCOPE
1.1 This test method uses air permeability to determine an envelope-specific surface area and its associated average equivalent spherical diameter of metal powders and related compounds. The powders may be analyzed in their "as-supplied" (shipped, received, or processed) condition or after they have been de-agglomerated or milled by a laboratory procedure ("lab milled") such as that specified in Practice B859. The values obtained are not intended to be absolute but are generally useful on a relative basis for control purposes.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information. Contact ASTM International (www.astm.org) for the latest information.
Designation: B 330 – 00
Standard Test Method for
Fisher Number of Metal Powders and Related Compounds
This standard is issued under the fixed designation B 330; 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. Terminology
1.1 This test method uses air permeability to determine an 3.1 Definitions—Many terms used in this test method are
envelope-specific surface area and its associated average defined in Terminology B 243.
equivalent spherical diameter of metal powders and related 3.2 Definitions of Terms Specific to This Standard:
compounds. The powders may be analyzed in their “as- 3.2.1 Fisher sub-sieve sizer, n—a commercially available
supplied” (shipped, received, or processed) condition or after permeability instrument for measuring envelope-specific sur-
they have been de-agglomerated or milled by a laboratory face area.
procedure (“lab milled”) such as that specified in Practice 3.2.2 envelope-specific surface area, n—the specific surface
B 859. The values obtained are not intended to be absolute but area of a powder as determined by gas permeametry in
are generally useful on a relative basis for control purposes. accordance with ISO/DIS 10070.
1.2 This standard does not purport to address all of the 3.2.3 air permeability, n—the measurement of air pressure
safety concerns, if any, associated with its use. It is the drop across a packed bed of powder.
responsibility of the user of this standard to establish appro- 3.2.4 de-agglomeration, n—process used to break up ag-
priate safety and health practices and determine the applica- glomerates of particles.
bility of regulatory limitations prior to use. 3.2.5 Fisher Number, n—a calculated value equated to an
average particle diameter, assuming all the particles are spheri-
2. Referenced Documents
cal and of uniform size.
2.1 ASTM Standards: 3.2.6 Fisher calibrator tube, n—a jewel with a precision
B 243 Terminology of Powder Metallurgy
orifice mounted in a tube similar to a sample tube. The
B 859 Practice for De-Agglomeration of Refractory Metal calibrator tube value is directly traceable to the master tube
Powders and Their Compounds Prior to Particle Size
maintained by Fisher.
Analysis 3.2.7 porosity of a bed of powder, n—the ratio of the
E 456 Terminology Relating to Quality and Statistics
volume of the void space in the powder bed to the that of the
E 691 Practice for Conducting an Interlaboratory Study to overall volume of the powder bed.
Determine the Precision of a Test Method
3.2.8 agglomerate, n—several particles adhering together.
2.2 ISO/DIS Document:
4. Significance and Use
10070 Metallic Powders Determinations of Envelope-
Specific Surface Area from Measurements of the Perme- 4.1 This test method provides a procedure for determining
ability to Air of a Powder Bed Under Steady-State Flow the envelope-specific surface area of powders which is equated
Conditions to an “average” particle diameter by calculation assuming the
2.3 MPIF Standard: particles are monosize, smooth surface nonporous spherical
32 Method for Determination of Average Particle Size of particles. For this reason, values obtained by this test method
Metal Powders Using the Fisher Subsieve Sizer will be defined as a Fisher Number. The degree of correlation
between the results of this test method and the quality of
powders in use will vary with each particular application and
1 has not been fully determined.
This test method is under the jurisdiction of ASTM Committee B-9 on Metal
Powders and Metal Powder Products and is the direst responsibility of Subcommit- 4.2 This test method is generally applicable to all metal
tee B09.03on Refractory Metal Powders.
powders and related compounds, including carbides, nitrides,
Current edition approved Oct. 10, 2000. Published January 2001. Originally
and oxides, for particles having diameters between 0.2 and 50
e1
published as B 330 - 58T. Last previous edition B 330 - 98 .
μm. It should not be used for powders composed of particles
Annual Book of ASTM Standards, Vol 02.05.
Annual Book of ASTM Standards, Vol 14.02.
whose shape is too far from equiaxed, that is, flakes or fibers.
Available from American National Standards Institute, 11 W. 42nd St., 13th
In these cases, it is permissible to use the test method described
Floor, New York, NY 10036.
5 only by agreement between the parties concerned. This test
Available from Metal Powder Industries Federation, 105 College Rd. East,
method shall not be used for mixtures of different powders nor
Princeton, NJ 08540–6692.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information. Contact ASTM International (www.astm.org) for the latest information.
B 330
for powders containing binders or lubricants. When the powder 6.1.3 The sample tube or plugs shall not be worn.
contains agglomerates, the measured surface area may be
6.1.4 The manometer and air resistors shall be free of visible
affected by the degree of agglomeration. Methods of de-
contamination.
agglomeration such as that referenced in 1.1 may be used if
6.1.5 The rubber sample tube seals shall not be worn to the
agreed upon between the parties concerned.
point where leakage occurs.
4.3 When an “average” particle size of powders is deter-
6.1.6 The sample packing post shall be properly adjusted.
mined using the Fisher sub-sieve sizer, it should be clearly kept
6.1.7 The drying agent shall be in proper condition.
in mind that this average size is derived from the determination
6.1.8 The manometer and standpipe levels shall be checked.
of the specific surface area of the powder using a relationship
6.1.8.1 Adjust the manometer only when the machine is not
that is true only for powders of uniform size and spherical
operating and with the pressure released for minimum of 5 min
shape.
to allow the manometer tube to drain completely.
6.2 The standardization of the Fisher sub-sieve sizer shall be
5. Apparatus
made using the Fisher jewel calibrator tube (jewel orifice tube)
5.1 The Fisher sub-sieve sizer consists of an air pump, an
as the primary standard. Specification shall be made at both
air-pressure regulating device, a precision-bore sample tube, a
ranges of the machine.
standardized double-range air flowmeter, and a calculator
The Fisher jewel calibrator tube used for standardization
chart. Included is accessory equipment consisting of a plug
shall be checked under a microscope at least once a month to
manipulator, powder funnel, two porous plugs, a supply of
determine the condition and cleanliness of the orifice.
paper disks, and a rubber tube support stand.
If the orifice is not clean, clean as described in the Fisher
sub-sieve sizer instruction manual.
NOTE 1—Necessary replacement parts should be obtained from the
manufacturer, especially in the case of the precision manometer which is
6.3 With the sub-sieve sizer properly adjusted and set to the
a part of the air flowmeter.
proper range, proceed as follows:
5.2 The manufacturer also furnishes directions which 6.3.1 Mount the Fisher jewel calibrator tube between the
should be followed except as amended as follows. Particular rubber seal supports just to the right of the brass post. Clamp
attention should be given to proper maintenance of the instru- the upper cap down onto the tube so that an airtight seal is
ment with special reference to the instructions on (1) periodic obtained at both ends.
checking of the water level in the pressure regulator standpipe,
6.3.2 Adjust the calculator chart so that the porosity reading
(2) manometer level before the sample tube is inserted, and (3) corresponds to the value indicated on the jewel calibrator tube.
the sample packing assembly.
6.3.3 Switch on the machine and allow it to warm up for a
5.3 Jewel Calibrator Tube—a standard for average particle
minimum of 20 min. Adjust the pressure-control knob, located
size measurement. It allows operators to relate their data to that
near the bubble observation window at the lower left of the
of other analysts. Each calibrator is factory tested three times
panel, until the bubbles rise in the standpipe at the rate of two
with the resulting readings and associated porosity recorded on
to three bubbles per second. This will cause the water line to
the tube.
rise above the calibration mark on the upper end of the
standpipe. This is normal and does not mean the calibration is
NOTE 2—Adjust the sample packing assembly (1) as described in the
in error.
manufacturer’s directions with the exception that the plugs and paper
disks are not inserted in the sample tube but are merely stacked together 6.3.4 The liquid level in the manometer tube will rise slowly
and placed between the brass support and the “flat” of the bottom of the
until it reaches a maximum. Allow at least 5 min for this to
rack of (2) as previously described except that a specially made baseline
happen. At the end of this period, using care not to disturb the
gage is used instead of the plugs and paper disks. This baseline gage shall
chart, turn the rack up until the upper edge of the crossbar
have a height of 19.30 6 0.10 mm. Check all plug heights when new plugs
coincides with the bottom of the liquid meniscus in the
are purchased and periodically thereafter to make sure all are equal in
manometer. The Fisher Number is indicated by the location of
height.
the pointer tip in relation to the curves on the calculator chart.
5.4 Balance—having a capacity of at least 50 g and a
Record the ambient temperature to the nearest 1°C. Release the
sensitivity of 0.001 g.
clamp on the upper end of the tube slowly so the manometer
returns to its zero position slowly with very little overshoot.
6. Standardization of Apparatus
This limits the formation of liquid droplets on the inside of the
6.1 Before proceeding with standardization of the Fisher
manometer tube.
sub-sieve sizer, the following items shall be checked:
6.3.5 The value obtained in this manner must correspond to
6.1.1 The chart shall be properly aligned horizontally with
the Fisher Number indicated on the jewel calibrator tube within
the indicator pointer.
61%.
6.1.2 The rack and pinion shall be properly aligned verti-
6.3.6 If the Fisher Number value as indicated on the chart
cally with the chart.
does not correspond to 61 % of the value indicated on the
jewel calibrator tube, calibrate the sub-sieve as follows: Adjust
either the high needle valve or the low needle valve as required
The manufacturer of the Fisher sub-sieve sizer #14-311A, is Fisher Scientific,
to bring the Fisher number indicated on the chart to the value
Instrument Division, 2000 Park Lane, Pittsburgh, PA 15275. Besides supplying the
indicated on the jewel calibrator tube. After adjustment is
basic instrument, they also supply accessories of: calibrator tube #14-313-7 and
sample calibrator, #14-311-2. made, repeat 6.3.4.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information. Contact ASTM International (www.astm.org) for the latest information.
B 330
NOTE 3—Because only one flowmeter is used for the low (0.2- to
sample pressure calibrator or an equivalent device.
20.0-μm) Fisher Number range while both flowmeters are used for the
7.3.6 Shift the calculator chart laterally until the extreme tip
high (20.0- to 50.0-μm) Fisher Number range, the low range should be
of the pointer just coincides with the sample-height curve on
standardized first. After the low range is standardized, the high range is
the chart. The pointer should be midway between the top and
then standardized, making adjustments only to the one flowmeter opened
bottom of the line. The chart must not be moved after this
up by the range-control knob.
setting until the determination is finished. Record the porosity
6.3.7 Standardization with the jewel calibrator tube is rec-
value indicated at the bottom of the chart.
ommended before and after any series of determinations or at
7.3.7 Without disturbing the sample in any way, mount the
least very4hof continued operation. Warm-up of the machine
sample tube between the rubber-cushioned supports just to the
is required if it has been off for more than 30 min.
right of the brass post. Clamp the upper cap down onto the
sample tube so that an airtight seal is obtained at both ends.
7. Procedure
7.1 Temperature of Test—Make Fisher Number determina- NOTE 4—The sample tube may eventually wear and cause faulty
values. When this condition is suspected, replace the tube. Sample tubes
tions with 62°C of the temperature at which standardization of
with obvious wear or scratches, or both, should be discarded.
the Fisher sub-sieve sizer was made. Restandardize if the
temperature of the test varies more than 62°C.
7.3.8 Determine the Fisher Number, switching on the ma-
7.2 Size of Test Sample—The mass of sample used for tests
chine and allowing the liquid level in the manometer tube to
should be equal in grams (within 60.01 g) to the theoretical
rise until it reaches a maximum. Allow a minimum of 5 min for
density of the powder (tungsten, 19.3 g; molybdenum, 10.22 g;
this to happen. The Fisher Number is indicated by the location
tantalum, 16.6 g; and so forth).
of the tip of the pointer in relation to the curves on the
7.3 Fisher Number Determination—The Fisher Number
calculator chart. Record this value along with the porosity for
determination shall be made by the same operator who makes
the sample and the ambient temperature at which the measure-
the standardizations and is started after standardization or the
ment was made.
determination of another sample. Proceed as follows:
NOTE 5—Formulas for calculating the Fisher Number or the equivalent
7.3.1 With the sub-sieve sizer properly adjusted, set the
spherical diameter and porosity values from sample and manometer
range control to the range desired.
heights are as follows:
7.3.2 Lay a paper disk over one end of the
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.