filled with 300 ml of the oil to be tested and
placed in the bath, which Is set to maintain the
sample at 140° F. The thermometer and stirrer
are Inserted through the beaker cover and into
the test oil. The stirrer is started, and when the
temperature of the sample reaches 140° F, the
steel specimen is inserted through another
opening In the beaker cover. Stirring continues
for 30 minutes, until the specimen is thoroughly
wetted by the oil. The thermometer is than
removed, and 30 ml of water (either the sea
water solution or distilled water) is added
through the thermometer opening. Stirring is
continued until the test is terminated.
placed in the bath, which Is set to maintain the
sample at 140° F. The thermometer and stirrer
are Inserted through the beaker cover and into
the test oil. The stirrer is started, and when the
temperature of the sample reaches 140° F, the
steel specimen is inserted through another
opening In the beaker cover. Stirring continues
for 30 minutes, until the specimen is thoroughly
wetted by the oil. The thermometer is than
removed, and 30 ml of water (either the sea
water solution or distilled water) is added
through the thermometer opening. Stirring is
continued until the test is terminated.
Observations of rusting made at the end of 12
hours are usually indicative of whether the oil
will pass or fail, although it is customary to run
the test for 24 hours, or even longer. At the end
of the test, the steel specimen is removed and
observations of rusting are made. A rusted
specimen, according to the test method, is one
on which any rust spot or streak is visible in
"normal" light (about 60 foot-candles).
hours are usually indicative of whether the oil
will pass or fail, although it is customary to run
the test for 24 hours, or even longer. At the end
of the test, the steel specimen is removed and
observations of rusting are made. A rusted
specimen, according to the test method, is one
on which any rust spot or streak is visible in
"normal" light (about 60 foot-candles).
Determination of "Pass" or Fail": In order to
report an oil as passing or failing, the test must
be conducted in duplicate. An oil is reported as
passing if specimens from both tests are rust-
free at the end of the test period. An oil is
reported as failing if both specimens are rusted
at the end of the test periods.
report an oil as passing or failing, the test must
be conducted in duplicate. An oil is reported as
passing if specimens from both tests are rust-
free at the end of the test period. An oil is
reported as failing if both specimens are rusted
at the end of the test periods.
If one of the specimens from the duplicate test
is rusted while the other is free of rust, the tests
are repeated on two additional specimens. If
either of these shows rust, the oil is reported as
failing.
is rusted while the other is free of rust, the tests
are repeated on two additional specimens. If
either of these shows rust, the oil is reported as
failing.
Degrees of Rusting: An indication of the de-
gree of rusting occurring in this test is
sometimes desired. For such cases, the follow-
ing classification is recommended:
gree of rusting occurring in this test is
sometimes desired. For such cases, the follow-
ing classification is recommended:
Light Rusting--Rusting confined to not more than
six spots, each of which is 1 mm or less in
diameter.
six spots, each of which is 1 mm or less in
diameter.
Moderate Rusting--Rusting in excess of the pre-
ceding, but confined to less than 5% of the
surface of the specimen.
ceding, but confined to less than 5% of the
surface of the specimen.
Severe Rusting--Rust covering more than 5% of
the surface of the specimen.
the surface of the specimen.
Reporting Results: Results obtained with a
given oll are reported as "Pass" or "Fall." Since
the test may be conducted with either distilled
water or with synthetic sea water, and for vary-
ing periods of time, reports of results should
always specify these conditions, For example:
"Rust Test, ASTM D 665. Procedure B. 24
Hours--Pass."
given oll are reported as "Pass" or "Fall." Since
the test may be conducted with either distilled
water or with synthetic sea water, and for vary-
ing periods of time, reports of results should
always specify these conditions, For example:
"Rust Test, ASTM D 665. Procedure B. 24
Hours--Pass."
Significance: When the lubricating oil of a
turbine or other system is contaminated with
water, rusting can result. Particles of rust in the
oil can act as catalysts that tend to increase the
rate of oil oxidation. Rust particles are abrasive,
and cause wear and scoring of critical parts. In
addition, rust particles can add to other contam-
inants in a circulating system, increasing the
tendency toward the clogging of low clearance
members, such as servo-valves, and increasing
the probability of filter plugging.
turbine or other system is contaminated with
water, rusting can result. Particles of rust in the
oil can act as catalysts that tend to increase the
rate of oil oxidation. Rust particles are abrasive,
and cause wear and scoring of critical parts. In
addition, rust particles can add to other contam-
inants in a circulating system, increasing the
tendency toward the clogging of low clearance
members, such as servo-valves, and increasing
the probability of filter plugging.
In many cases, the rusting characteristics of the
system in service are better than is indicated by
testing a sample of the used oil. Because the
polar rust inhibitor "plates out" on the metal
surfaces (which are therefore adequately pro-
tected). The sample of oil, being somewhat
depleted of the inhibitor, will then allow greater
rusting in tile test than would occur in service.
system in service are better than is indicated by
testing a sample of the used oil. Because the
polar rust inhibitor "plates out" on the metal
surfaces (which are therefore adequately pro-
tected). The sample of oil, being somewhat
depleted of the inhibitor, will then allow greater
rusting in tile test than would occur in service.
The relative ability of an oil to prevent rusting
can become a critical property in many applica-
tions. As noted, this test method was originally
applied exclusively to steam turbine oils. How-
ever, the test is now frequently applied to other
oils in different types of applications, whenever
undesirable water contamination is a possibility.
can become a critical property in many applica-
tions. As noted, this test method was originally
applied exclusively to steam turbine oils. How-
ever, the test is now frequently applied to other
oils in different types of applications, whenever
undesirable water contamination is a possibility.
(FIST 2-4 11/90)
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