ASTM B962-23

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
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Designation: B962 − 17 B962 − 23
Standard Test Methods for
Density of Compacted or Sintered Powder Metallurgy (PM)
Products Using Archimedes’ Principle
This standard is issued under the fixed designation B962; 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 (´) 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 This standard describes a method for measuring the density of powder metallurgy products that usually have surface-connected
porosity.
1.2 The density of impermeable PM materials, those materials that do not gain mass when immersed in water, may be determined
using Test Method B311.
1.3 The current method is applicable to green compacts, sintered parts, and green and sintered test specimens.
1.4 With the exception of the values for density and the mass used to determine density, for which the use of the gram per cubic
centimetre (g/cm ) and gram (g) units is the long-standing industry practice, the values in inch-poundSI units are to be regarded
as standard. The values given in parentheses are mathematical conversions to after SI units that are provided for information only
and are not considered standard.
1.5 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 healthsafety, health, and environmental practices and determine
the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
B243 Terminology of Powder Metallurgy
B311 Test Method for Density of Powder Metallurgy (PM) Materials Containing Less Than Two Percent Porosity
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
These test methods are under the jurisdiction of ASTM Committee B09 on Metal Powders and Metal Powder Products and are the direct responsibility of Subcommittee
B09.04 on Bearings.
Current edition approved April 1, 2017Sept. 1, 2023. Published May 2017September 2023. Originally approved in 2008. Last previous edition approved in 20152017 as
B962 – 15. DOI: 10.1520/B0962-17.17. DOI: 10.1520/B0962-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B962 − 23
3. Terminology
3.1 Definitions of powder metallurgy (PM) terms can be found in Terminology B243. Additional descriptive material is available
in the Related Material section of Vol. 02.05 of the under “General Information on PM” on the Annual Book of ASTM
Standards.ASTM B09 web page.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 green density (D )—the mass per unit volume of an unsintered PM part or test specimen.
g
3.2.2 impregnated density (D )—the mass per unit volume of a sintered PM part or test specimen, impregnated with oil.
i
3.2.3 sintered density (D )—the mass per unit volume of a sintered, non oil-impregnated PM part or test specimen.
s
4. Summary of Test Method
4.1 The test specimen is first weighed in air. It is then oil impregnated or some other treatment is used to seal the surface-connected
porosity and the specimen is reweighed. The test specimen is then weighed when immersed in water and its density calculated
based on Archimedes’ principle.
5. Significance and Use
5.1 The volume of a complex shaped PM part cannot be measured accurately using micrometers or calipers. Since density is mass
per unit volume, a precise method for measuring the volume is needed. Archimedes’ principle may be used to calculate the volume
of water displaced by an immersed object. For this to be applicable to PM materials that contain surface connected porosity, the
surface pores are sealed by oil impregnation or some other means.
5.2 The green density of compacted parts or test pieces is normally determined to assist during press set-up, or for quality control
purposes. It is also used for determining the compressibility of base powders, mixed powders, and premixes.
5.3 The sintered density of sintered PM parts and sintered PM test specimens is used as a quality control measure.
5.4 The impregnated density of sintered bearings is normally measured for quality control purposes as bearings are generally
supplied and used oil-impregnated.
6. Interferences
6.1 A gain in mass when a test specimen is immersed in water is an indication that the specimen contains surface-connected
porosity. Unsealed surface porosity will absorb water and cause the calculated density values to be higher than the true value.
6.2 Test specimens that contain surface-connected porosity shall be oil impregnated or have the surface-connected porosity sealed
by some other means prior to their immersion in water.
7. Apparatus
7.1 Analytical Balance—Precision single-pan balance that will permit readings within 0.01% of the test specimen mass. See Table
1. The analytical balance shall be supported in a manner to eliminate mechanical vibrations and be shielded from air drafts.
TABLE 1 Balance Readability
Mass, Balance Readable to,
g g
less than 10 0.0001
10 to less than 100 0.001
100 to less than 1000 0.01
1000 to less than 10 000 0.1
B962 − 23
7.2 Water—Distilled or deionized and preferably degassed water to which 0.05 to 0.1 volume percent of a wetting agent has been
added to reduce the effects of surface tension. The density of distilled water changes as a function of water temperature and
therefore should be accounted for when calculating the density of the specimen. Table 2.
NOTE 1—Degassing the water by evacuation, boiling, or ultrasonic agitation helps to prevent air bubbles from collecting on the test specimen and support
when immersed in water.
TABLE 2 Maximum Recommended Wire Diameters
Mass, Wire Diameter,
g in. (mm)
less than 50 0.005 (0.12)
50 to less than 200 0.010 (0.25)
200 to less than 600 0.015 (0.40)
600 and greater 0.020 (0.50)
A
TABLE 3 Effect of Temperature on the Density of Air-Free Water
Temperature Density
°F (°C) g/cm
59.0 (15) 0.9991
60.8 (16) 0.9989
62.6 (17) 0.9988
64.4 (18) 0.9986
66.2 (19) 0.9984
68.0 (20) 0.9982
69.8 (21) 0.9980
71.6 (22) 0.9978
73.4 (23) 0.9975
75.2 (24) 0.9973
77.0 (25) 0.9970
78.8 (26) 0.9968
80.6 (27) 0.9965
82.4 (28) 0.9962
84.2 (29)
0.9959
86.0 (30) 0.9956
A
TABLE 2 Effect of Temperature on the Density of Air-Free Water
Temperature ρ Temperature ρ
w w
3 3
°C g/cm °F g/cm *
15.0 0.9991 60 0.9990
15.5 0.9990 61 0.9989
16.0 0.9989 62 0.9988
16.5 0.9988 63 0.9987
17.0 0.9988 64 0.9986
17.5 0.9987 65 0.9985
18.0 0.9986 66 0.9984
18.5 0.9985 67 0.9983
19.0 0.9984 68 0.9982
19.5 0.9983 69 0.9981
20.0 0.9982 70 0.9980
20.5 0.9981 71 0.9978
21.0 0.9980 72 0.9977
21.5 0.9979 73 0.9975
22.0 0.9978 74 0.9974
22.5 0.9976 75 0.9973
23.0 0.9975 76 0.9972
23.5 0.9974 77 0.9970
24.0 0.9973 78 0.9969
24.5 0.9972 79 0.9967
25.0 0.9970 80 0.9966
25.5 0.9969 81 0.9964
26.0 0.9968 82 0.9963
26.5 0.9966 83 0.9961
27.0 0.9965 84 0.9959
27.5 0.9964 85 0.9958
28.0 0.9962 86 0.9956
28.5 0.9961
29.0 0.9959 *Interpolated from
29.5 0.9958 °C data
30.0 0.9956
A
Metrological Handbook 145, “Quality Assurance for Measurements,” National Institute of Standards and Technology, 1990, pp. 9-10.
B962 − 23
7.3 Water Container—A glass beaker or other suitable transparent container should be used to contain the water.
NOTE 2—A transparent container makes it easier to see air bubbles adhering to the test specimen and specimen support when immersed in water.
NOTE 3—For the most precise density determination, the water container should be of a size that the level of the water does not rise more than 0.10 in.
(2.5 mm) 2.5 mm (0.10 in.) when the test specimen is lowered into the water.
7.3 Water—Distilled or deionized water to which 0.05 to 0.1 volume percent of a wetting agent has been added to reduce the
effects of surface tension.
NOTE 3—Degassing the water by evacuation, boiling, or ultrasonic agitation helps to prevent air bubbles from collecting on the test specimen and support
when immersed in water.
7.4 Test Specimen Support for Weighing in Water—Two typical arrangements are shown in Fig. 1. The suspension wire may be
twisted around the test specimen or the test specimen may be supported in a wire basket that is attached to the suspension wire.
For either arrangement, a single corrosion-resistant wire—for example, austenitic stainless steel, copper, or nichrome—shall be
used for the basket and suspension wire. The For the maximum recommended diameter of suspension wire to be used for various
mass ranges is summarized in see Table 23.
NOTE 4—For the most precise density determinations, it is important that the mass and volume of all supporting wires immersed in water be minimized.
-6 2 -6 2
7.5 Oil for Oil-Impregnation—Oil with a viscosity of 20 to 65 cSt or 100 to 300 SSU (20 × 1020 × 10 m /s to 65 × 10 m /s)
at/s (20 to
100 °F (38 °C) 65 cSt (centistokes) or 100 to 300 Saybolt Universal Seconds (SUS)) at 38 °C (100 °F) has been found to be
suitable.
7.5.1 In the case of oil-impregnated bearings, make an effort to match the oil that was originally used to impregnate them.
FIG. 1 Methods for Holding the Test Specimen When Weighing in Water
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TABLE 3 Maximum Recommended Wire Diameters
Mass, Wire Diameter,
g in. (mm)
less than 50 0.12 (0.005)
50 to less than 200 0.25 (0.010)
200 to less than 600 0.38 (0.015)
600 and greater 0.50 (0.020)
7.6 Vacuum Impregnation Apparatus—Equipment to impregnate the part or test specimen with oil.
7.7 Thermometer—A thermometer with an accuracy of
1.0 °F (0.5 °C) to measure the temperature of the water.water to the nearest 0.5 ºC (1 ºF).
8. Preparation of Test Specimens
8.1 The mass of the test specimen shall be a minimum of
1.0 g. 1.0 g. For small parts, several parts may be combined to reach the minimum mass.
8.2 Thoroughly clean all surfaces of the test specimen to remove any adhering foreign materials such as dirt or oxide scale. Take
care with cut specimens to avoid rough surfaces to which an air bubble may adhere. A 100-grit sanding or abrasive grinding is
recommended to remove all rough surfaces.
9. Procedure
9.1 The part or test specimen, the analytical balance and surrounding air shall be at a uniform temperature when weighing is
performed.
9.2 For the most precise density determinations, duplicate weighings should be made for all mass measurements. Adjust the
analytical balance to zero prior to each weighing. Average the mass determinations before calculating the density.
9.3 For improved repeatability and reproducibility, verify the analytical balance periodically with a standard mass that is
approximately equal to the part or test specimen mass.
9.4 This standard contains three separate test methods; determination of green density, determination of sintered density, and
determination of impregnated density. Each is detailed in the following sections.
Determination of Green Density
9.5 This procedure is used to determine the green density of as-compacted PM parts and test specimens. In order to determine
accurately the volume of the test specimens by water displacement, the specimens shall be oil impregnated, or the pores filled with
a suitable alternative material of known density. The density determined is an average of the metal additives, and any solid
lubricant originally present that was used to aid compaction.
9.5.1 Determine the mass of the green part or test specimen. This is mass A. This and all subsequent weighings shall be to the
precision stated in Table 1.
9.5.2 Oil impregnate the green part or test specimen as follows:
Preferred Vacuum Oil Impregnate—Preferred Procedure
9.5.3 Immerse the part or test specimen in oil at room temperature.
9.5.4 Reduce the pressure over the sample to 1 psi (7 kPa)7 kPa (1 psi) or less for 30 minutes,min, then increase the pressure back
to atmospheric pressure and keep the sample immersed for at least 30 minutes.min.
B962 − 23
9.5.5 Remove excess oil by wipingblotting gently with an absorbent, lint-free material. Take care not to extract oil absorbed within
the part or test specimen.
9.5.6 Do not place or store parts on porous surfaces such as paper, cloth, or cardboard as these will absorb oil.
9.5.7 Proceed to 9.5.13.
Alternative Immersion Oil Impregnate—Alternative Procedure
9.5.8 Immerse the part or test specimen in oil at a temperature of 180 6 10 °F (82 6 5 °C) 82 °C 6 5 °C (180 °F 6 10 °F) for
at least 4 hours.h.
9.5.9 Cool by immersing in a bath of the same oil held at room temperature and keep in this oil for at least 30 minutes.min.
9.5.10 Remove excess oil by wipingblotting gently with an absorbent, lint-free material. Take care not to extract oil absorbed
within the part or test specimen.
9.5.11 Do not place or store parts on porous surfaces such as paper, cloth, or cardboard as these will absorb oil.
9.5.12 Proceed to 9.5.13.
NOTE 5—It may not be necessary to oil impregnate the green part with oil. There may be enough admixed lubricant present in the surface-connected pores
to prevent the absorption of water. If the test specimen gains mass when immersed in water it is an indication that the specimen contains surface-connected
porosity and that it needs to be sealed by oil impregnation or some other means.
9.5.13 Determine the mass of the oil-impregnated green part or test specimen to the precision stated in Table 1. This is mass B.
9.5.14 Support the container of water over the pan of the balance using a suitable bridge as shown in Fig. 2a. Take care to ensure
that the bridge does not restrict the free movement of the balance pan. The container of water may also be supported below the
balance for weighing larger specimens if the balance has a lower beam hook for this purpose. See Fig. 2b. If this arrangement is
used, it is important to shield the weighing system, includin
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