Significance of the Tests: Under standardized
conditions, the 4-Ball .Wear Test provides a
means for comparing the relative anti-wear
properties of lubricants. It Is not possible to
directly compare the results of two tests run
under different conditions, so operating condi-
tions should always be reported with the test
results. No correlation has yet been established
between the 4-Ball Wear Test and field service,
so Individual results should not be used to pre-
dict field performance.
conditions, the 4-Ball .Wear Test provides a
means for comparing the relative anti-wear
properties of lubricants. It Is not possible to
directly compare the results of two tests run
under different conditions, so operating condi-
tions should always be reported with the test
results. No correlation has yet been established
between the 4-Ball Wear Test and field service,
so Individual results should not be used to pre-
dict field performance.
The 4-Ball EP Test is used in lubricant quality
control, and to differentiate between lubricants
having Iow, medium, and high extreme pressure
qualities. Judgment of the relative EP properties
of two oils or two greases should not be made
control, and to differentiate between lubricants
having Iow, medium, and high extreme pressure
qualities. Judgment of the relative EP properties
of two oils or two greases should not be made
on the basis of results differing by less than the
repeatability or reproducibility of the test. The
results of the EP Test do not necessarily
correlate with actual service results. Test results
should not be used to predict field performance
unless other lubricant properties are also taken
into consideration.
repeatability or reproducibility of the test. The
results of the EP Test do not necessarily
correlate with actual service results. Test results
should not be used to predict field performance
unless other lubricant properties are also taken
into consideration.
Using Wear and EP Tests Together: In com-
paring the capabilities of various lubricants, the
results of both the EP and Wear Test should be
considered; this is particularly true if additives or
grease thickeners are unknown or are widely
dissimilar. Lubricants that have good extreme
pressure properties may not be equally effective
in reducing wear rates at less severe loads, and
conversely.
paring the capabilities of various lubricants, the
results of both the EP and Wear Test should be
considered; this is particularly true if additives or
grease thickeners are unknown or are widely
dissimilar. Lubricants that have good extreme
pressure properties may not be equally effective
in reducing wear rates at less severe loads, and
conversely.
GREASE CONSISTENCY
ASTM D 217 and D 1403
The consistency of a lubricating grease is de-
fined as its resistance to deformation under an
applied force--in other words, its relative stiff-
ness or hardness. The consistency of a grease
is often important in determining its suitability for
a given application.
fined as its resistance to deformation under an
applied force--in other words, its relative stiff-
ness or hardness. The consistency of a grease
is often important in determining its suitability for
a given application.
Grease consistency is given a quantitative basis
through measurement with the ASTM Cone
Penetrometer. The method consists of allowing
a weighted metal cone to sink into the surface of
the grease, and measuring the depth to which
the point falls below the surface. This depth, in
tenths of millimeters, is recorded as the pene-
tration, or penetration number, of the grease.
The softer the grease, the higher its penetration.
through measurement with the ASTM Cone
Penetrometer. The method consists of allowing
a weighted metal cone to sink into the surface of
the grease, and measuring the depth to which
the point falls below the surface. This depth, in
tenths of millimeters, is recorded as the pene-
tration, or penetration number, of the grease.
The softer the grease, the higher its penetration.
The ASTM D 217 method recognizes five differ-
ent categories of penetration, depending on the
condition of the grease when the measurement
is made. Undisturbed penetration is determined
with the grease in its original container.
Unworked penetration is the penetration of a
sample which has received only minimum dis-
ent categories of penetration, depending on the
condition of the grease when the measurement
is made. Undisturbed penetration is determined
with the grease in its original container.
Unworked penetration is the penetration of a
sample which has received only minimum dis-
turbance in being transferred from the sample
can to the test cup. Worked penetration is the
penetration of a grease sample that has been
subjected to 60 double strokes in a standard
grease worker (to be described). Prolonged
worked penetration is measured on a sample
that has been worked the specified number of
strokes (more than 60), brought back to 77° F,
then worked an additional 60 double strokes in
the grease worker. Block penetration is the
penetration of a block grease--a grease hard
enough to hold its shape without a container.
All the above penetrations are determined on
samples that have been brought to 77° F.
can to the test cup. Worked penetration is the
penetration of a grease sample that has been
subjected to 60 double strokes in a standard
grease worker (to be described). Prolonged
worked penetration is measured on a sample
that has been worked the specified number of
strokes (more than 60), brought back to 77° F,
then worked an additional 60 double strokes in
the grease worker. Block penetration is the
penetration of a block grease--a grease hard
enough to hold its shape without a container.
All the above penetrations are determined on
samples that have been brought to 77° F.
Apparatus and Materials: The ASTM Cone
Penetrometer consists of a metal cone of spec-
ified weight and dimensions, an adjustable
assembly, and a depth indicator.
Penetrometer consists of a metal cone of spec-
ified weight and dimensions, an adjustable
assembly, and a depth indicator.
The standard grease worker is a motor-driven
device consisting of a container fitted with a
perforated plunger, which moves up and down
device consisting of a container fitted with a
perforated plunger, which moves up and down
(FIST 2-4 11/90)
A-8