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NOTE 2—Degassing the water by evacuation, boiling, or ultrasonic
agitation helps to prevent air bubbles from collecting on the test specimen
and specimen support when immersed in water.

6.3 Water Container—A glass beaker or other suitable
transparent container should be used to contain the water.

NOTE 3—A transparent container makes it easier to see air bubbles
adhering to the test specimen and specimen support when immersed in

NOTE 4—For the most precise density determination, the water con-
tainer should be of a size that the level of the water does not rise more than
2.5 mm when the test specimen is lowered into the water.

6.4 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,
nichrome—shall be used for the basket and suspension wire.
For the maximum recommended diameter of suspension wire
to be used for various mass ranges see Table 2.

NOTE 5—For the most precise density determinations, it is important
that the mass and volume of all supporting wires immersed in water be

6.5 Thermometer—A thermometer with an accuracy of
0.2 °C to measure the temperature of the water.

7. Preparation of Test Specimens

7.1 A complete part or a section of a part may be used for
the test specimen. For the highest precision, the test specimen
shall have a minimum mass of 5.0 g. If less precision can be
tolerated, several test specimens may be used to reach the
minimum mass, provided each test specimen has a mass of not
less than 1.0 g.

7.2 All test specimen surfaces shall be thoroughly cleaned
of all adhering foreign materials, such as, dirt, grease, oil,
oxide scale, metal powders or assembly materials. For cut

TABLE 1 Balance Sensitivity

Mass, g Balance Sensitivity, 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

TABLE 2 Maximum Recommended Wire Diameter

Mass, g Wire Diameter, mm

less than 50 0.12
50 to less than 200 0.25
200 to less than 600 0.40
600 and greater 0.50

FIG. 1 Methods for Holding the Test Specimen When Weighing in Water

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specimens, care must be used to avoid rough surfaces to which
an air bubble can adhere. A 100-grit sanding or abrasive
grinding is recommended to remove all rough surfaces.

8. Procedure

8.1 Weigh the test specimen in air using an analytical
balance. This is mass A. This and all subsequent weighings
shall be to 0.01% of the test specimen mass.

It is important that the test specimen, analytical balance and
surrounding air be at a uniform temperature when the weighing
is performed.

NOTE 6—For improved reproducibility, the analytical balance should be
periodically calibrated with a standard mass that is approximately equal to
the test specimen mass.

8.2 Support the container of water over the pan of the
balance using a suitable bridge as shown in Fig. 2. 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 suspension wire between the
container of water and the bottom of the balance from air

8.3 Suspend the test specimen support with the test speci-
men from the beam hook of the balance. The water should
cover any wire twists and the specimen support basket by at
least 6 mm to minimize the effect of surface tension forces on
the weighing. Care should be taken to ensure that the test
specimen and specimen support hang freely from the balance
beam hook, are free of air bubbles where immersed in the
water and are at the same temperature as the water and balance.
Care should also be taken to ensure the surface of the water is
free of dust particles.

8.4 Weigh the test specimen and specimen support im-
mersed in water. This is mass B.

8.5 Remove the test specimen. Weigh the test specimen
support immersed in water at the same depth as before. This is
mass C. Care should be taken to ensure that the suspension
support is free of air bubbles and that the suspension wire is not
immersed below its normal hanging depth as a change in depth
will change the measured mass.

NOTE 7—Some balances are capable of being tared. This automatically
removes the necessity of reweighing the specimen support every time. In
this case, tare the specimen support alone, immersed in water to the same
depth as with the specimen, before weighing the specimen support and

FIG. 2 Methods for Weighing in Water

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specimen immersed in water. The mass of the specimen support and
specimen immersed in water is mass F, which replaces mass B minus
mass C.

8.6 Measure the temperature of the water to the nearest
0.5 °C and record its density E, at that temperature, from
Table 3.

9. Calculation

9.1 Calculate the density as follows:

Density 5 D 5 Mass/Volume (1)

D 5 A/
@A 2 ~B 2 C!#


D 5 ~A 3 E!/~A 2 B1C! 5 ~A 3 E!/~A 2 F! (3)

D = density of test specimen, g/cm3,
A = mass of test specimen in air, g,
B = apparent mass of test specimen and specimen support in

water, g,
C = mass of specimen support immersed in water, g,
F = mass of test specimen in water with mass of specimen

support tared, g, and
E = density of water in g/cm3.

10. Report

10.1 Report the density rounded to the nearest 0.01 g/cm3.

11. Precision and Bias

11.1 Interlaboratory Test Program—An interlaboratory
study of the Density Test Method was run in 1990. Eleven test
laboratories tested eighteen different materials. The design of
the study followed Practice E691 and a within-between analy-
sis of the data are given in Research Report RR:B09-10143.

11.2 Test Results—The precision information presented
herein has been calculated for the results from eleven labora-
tories and for duplicate results for each of eighteen materials

11.3 Precision:
11.3.1 95% Repeatability Limit (within a laboratory)—The

within-laboratory repeatability limit, r, as defined by Termi-
nology E456, is estimated to be 0.025 g/cm3. At the 95%
confidence level, duplicate density test results from the same
laboratory should not be considered different unless they differ
by more than r.

11.3.2 95% Reproducibility Limit (between laboratories)—
The between laboratories reproducibility limit, R, as defined by
Terminology E456, is estimated to be 0.03 g/cm3 for test
specimens with a mass of greater than 5 g. For test specimens
with a mass of from 1 to 5 g it is estimated to be 0.05 g/cm3.
At the 95% confidence level, duplicate density test results from
different laboratories should not be considered different unless
they differ by more than R.

11.4 Bias—No information can be presented on the bias of
the procedure in Test Method B311 for measuring Density
because no material having an accepted reference value is

11.5 Measurement Uncertainty—The precision of Test
Method B311 shall be considered by those performing the test
when reporting Density test results.

12. Keywords

12.1 cemented carbides; density; hard metals; metal injec-
tion molded (MIM) parts; powder metallurgy (PM); powder
forged (PF) parts; powder metallurgy

3 Supporting data have been filed at ASTM International Headquarters and may
be obtained by requesting Research Report RR:B09-1014. Contact ASTM Customer
Service at [email protected]

TABLE 3 Density of Air-Free WaterA

Temperature (°C) Density (g/cm3)

18.0 0.9986
18.5 0.9985
19.0 0.9984
19.5 0.9983
20.0 0.9982
20.5 0.9981
21.0 0.9980
21.5 0.9979
22.0 0.9978
22.5 0.9976
23.0 0.9975
23.5 0.9974
24.0 0.9973
24.5 0.9972
25.0 0.9970
25.5 0.9969
26.0 0.9968
26.5 0.9966
27.0 0.9965
27.5 0.9964
28.0 0.9962
28.5 0.9961
29.0 0.9959
29.5 0.9958
30.0 0.9956

AMetrological Handbook 145, “Quality Assurance for Measurements,” National
Institute of Standards and Technology, 1990, p. 9.10.

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