ASTM G137-97(2003)
(Test Method)Standard Test Method for Ranking Resistance of Plastic Materials to Sliding Wear Using a Block-On-Ring Configuration
Standard Test Method for Ranking Resistance of Plastic Materials to Sliding Wear Using a Block-On-Ring Configuration
SIGNIFICANCE AND USE
The specific wear rates determined by this test method can be used as a guide in ranking the wear resistance of plastic materials. The specific wear rate is not a material property and will therefore differ with test conditions and test geometries. The significance of this test will depend on the relative similarity to the actual service conditions.
This test method seeks only to describe the general test procedure and the procedure for calculating and reporting data.
Note 2—This test configuration allows steady state specific wear rates to be achieved very quickly through the use of high loads and speeds. The thrust washer configuration described in Test Method D 3702 does not allow for the use of such high speeds and loads because of possible overheating (which may cause degradation or melting, or both) of the specimen. Despite the differences in testing configurations, a good correlation in the ranking of wear resistance is achieved between the two tests (Table X2.1).
SCOPE
1.1 This test method covers a laboratory procedure to measure the resistance of plastic materials under dry sliding conditions. The test utilizes a block-on-ring geometry to rank materials according to their sliding wear characteristics under various conditions.
1.2 The test specimens are small so that they can be molded or cut from fabricated plastic parts. The test may be run at the load, velocity, and temperature which simulate the service condition.
1.3 Wear test results are reported as specific wear rates calculated from volume loss, sliding distance, and load. Materials with superior wear resistance have lower specific wear rates.
1.4 This test method allows the use of both single- and multi-station apparatus to determine the specific wear rates.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.6 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.
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Standards Content (Sample)
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Designation: G 137 – 97 (Reapproved 2003)
Standard Test Method for
Ranking Resistance of Plastic Materials to Sliding Wear
Using a Block-On-Ring Configuration
This standard is issued under the fixed designation G137; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope ASTM Test Methods
G40 Terminology Relating to Wear and Erosion
1.1 This test method covers a laboratory procedure to
G77 Test Method for Ranking Resistance of Materials to
measure the resistance of plastic materials under dry sliding
Sliding Wear Using Block-on-Ring Wear Test
conditions. The test utilizes a block-on-ring geometry to rank
G117 Guide for Calculating and Reporting Measures of
materials according to their sliding wear characteristics under
Precision Using Data from Interlaboratory Wear or Ero-
various conditions.
sion Tests
1.2 Thetestspecimensaresmallsothattheycanbemolded
or cut from fabricated plastic parts. The test may be run at the
3. Terminology
load, velocity, and temperature which simulate the service
3.1 Definitions:
condition.
3.1.1 wear—damage to a solid surface, generally involving
1.3 Wear test results are reported as specific wear rates
progressive loss of material, due to relative motion between
calculated from volume loss, sliding distance, and load. Mate-
that surface and a contacting substance or substances.
rials with superior wear resistance have lower specific wear
3.1.2 Additional definitions relating to wear are found in
rates.
Terminology G40.
1.4 This test method allows the use of both single- and
3.2 Definitions of Terms Specific to This Standard:
multi-station apparatus to determine the specific wear rates.
3.2.1 specific wear rate—the volume loss per unit sliding
1.5 The values stated in SI units are to be regarded as the
distance,dividedbytheload.Itcanbecalculatedasthevolume
standard. The values given in parentheses are for information
loss per unit time, divided by the load and the sliding velocity.
only.
3.2.2 steady state specific wear rate—the specific wear rate
1.6 This standard does not purport to address all of the
that is established during that part of the test when the specific
safety concerns, if any, associated with its use. It is the
wear rate remains substantially constant (the specific wear rate
responsibility of the user of this standard to establish appro-
versusslidingdistancecurveflattensoutconsiderablywithless
priate safety and health practices and determine the applica-
than 30% difference between the specific wear rates) during a
bility of regulatory limitations prior to use.
minimumofthreetimeintervalsspanningatotaltimeduration
2. Referenced Documents of at least 18 h, with ideally no single interval exceeding 8 h.
However, one time interval during the steady state can be as
2.1 ASTM Standards:
2 long as 16 h.
D618 Practice for Conditioning Plastics for Testing
D3702 Test Method for Wear Rate and Coefficient of
4. Summary of Test Method
Materials in Self-Lubricated Rubbing Contact Using a
3 4.1 A plastic block of known dimensions is brought into
Thrust Washer Testing Machine
contact with a counterface ring (usually metal) under con-
E122 Practice for Calculating Sample Size to Estimate,
trolledconditionsofcontactpressureandrelativevelocity.This
With a Specified Tolerable Error, the Average for Charac-
isachievedusingablock-on-ringconfigurationasillustratedin
teristic of a Lot or Process
Fig. 1. Periodic weighing of the polymer block results in a
E177 Practice for Use of the Terms Precision and Bias in
number of mass-time data points where the time relates to the
timeofsliding.Thetestiscontinueduntilthesteadystatewear
rate is established. Mass loss measurements made after the
This test method is under the jurisdiction of ASTM Committee G02 on Wear
and Erosion and is the direct responsibility of Subcommittee G02.40 on Non- steadystateisestablishedareusedtodeterminethesteadystate
Abrasive Wear.
specific wear rate, which is the volume loss per unit sliding
Current edition approved June 10, 2003. Published July 2003. Originally
distance per unit load. The frictional torque may also be
approved in 1995. Last previous edition appeared in 1997 as G137–97.
Annual Book of ASTM Standards, Vol 08.01.
Annual Book of ASTM Standards, Vol 05.02.
4 5
Annual Book of ASTM Standards, Vol 14.02. Annual Book of ASTM Standards, Vol 03.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
G 137 – 97 (2003)
FIG. 1 Single Station Block-on-Ring Arrangement
measured during the steady state using a load cell. These data figures shown in this test method represent one example of a
can be used to evaluate the coefficiency of friction for the test block-on-ring test apparatus. The mandatory elements are: the
combination. capability to change load and sliding speed, the ability to
reposition the specimen after weighing as before, and a
NOTE 1—Anothertestmethodthatutilizesablock-on-ringtestconfigu-
counterface ring with acceptable eccentricity.All other design
ration for the evaluation of plastics is Test Method G77.
elements can be varied according to the user preference.
5. Significance and Use
6.1.1 Bearings recommended for counterface drive shafts
are industrial-grade tapered roller bearings.
5.1 The specific wear rates determined by this test method
can be used as a guide in ranking the wear resistance of plastic 6.1.2 Required centerline alignment limits of the counter-
materials.The specific wear rate is not a material property and
facedriveshaftsare 60.41mm(60.016in.)fromthecenterof
will therefore differ with test conditions and test geometries. a counterface ring. Allowable eccentricity of the counterface
The significance of this test will depend on the relative ring is no greater than 60.06 mm (60.002 in.).
similarity to the actual service conditions.
6.1.3 Bearings recommended for the linear ball grooved
5.2 This test method seeks only to describe the general test
bushing bearing are industrial-grade linear bearings.
procedureandtheprocedureforcalculatingandreportingdata.
6.2 Counterface Ring—The recommended dimensions for
the counterface ring are 100+0.05,−0.00-mm diameter and
NOTE 2—This test configuration allows steady state specific wear rates
tobeachievedveryquicklythroughtheuseofhighloadsandspeeds.The 15.88+0.30,−0.13-mm width. Often a hardened tool steel
thrust washer configuration described in Test Method D3702 does not
ring with a hardness of 50 to 60 HRC and a surface roughness
allow for the use of such high speeds and loads because of possible
of 0.102 to 0.203 µm (4 to 8 µin.) R in the direction of sliding
a
overheating (which may cause degradation or melting, or both) of the
is used for the general evaluation of plastics. The requirement
specimen. Despite the differences in testing configurations, a good
for the ring material is that it should not wear appreciably or
correlation in the ranking of wear resistance is achieved between the two
change dimensions during the course of the test. Therefore,
tests (Table X2.1).
other materials and surface conditions may also be used. It
6. Apparatus and Materials
should be noted that test results will be influenced by the
choice of ring material and surface roughness.
6.1 Test Setup—An example of the basic test configuration
and part names are shown in Fig. 1. The recommended 6.3 Test Block—The recommended dimensions of the test
dimensions of the test apparatus are shown in Fig. 2. The block are 6.35+0.00,−0.03-mm (0.250+0.000,−0.001-in.)
G 137 – 97 (2003)
NOTE—All dimensions are given in millimetres.
FIG. 2 Recommended Dimensions of Block-on-Ring Apparatus
width, 6.00 + 0.00, − 0.03-mm (0.236 + 0.000, − 0.001-in.) 7.2 Both solvents are flammable and toxic. Refer to the
depth, and 12.70 6 0.2-mm height. For materials where relevant Material Safety Data Sheet (MSDS) before using the
surface condition is not a parameter under study, a ground solvents.
surface with the grinding marks running parallel to the depth
direction of the block and a roughness of 0.102 to 0.203 µm (4 8. Preparation and Calibration of Apparatus
to 8 µin.) R in the direction of motion is recommended.
a
8.1 Perform calibration of torque transducers by applying
However, other surface conditions may be evaluated as de-
NIST traceable dead weight standards and using a reference
sired. 6
load cell.
6.4 Test Parameters:
8.2 Perform calibration of tachometer by comparison to a
6.4.1 The recommended range for the normal load is from
hand-held tachometer which has been calibrated with NIST
20 to 40 N.
traceable standards.
6.4.2 Therecommendedrangeforthevelocityisfrom0.5to
1 m/s.
9. Conditioning
6.5 Apparatus:
9.1 Conditioning—Condition the test specimens at 23 6
6.5.1 Analytical Balance, capable of measuring to the near-
2°C(73.4 63.6°F)and50 65%relativehumidityfornotless
est 0.01 mg.
than 40 h prior to testing in accordance with Procedure A of
Practice D618 for those samples where conditioning is re-
7. Reagents
quired.
7.1 Suitable cleaning procedures should be used to clean
counterface ring and test block. Reagents proven suitable for
some materials are:
7.1.1 Acetone, for steel rings, and
The interlaboratory tests were conducted using the torque transducers manu-
7.1.2 Methanol, for test block surface and specimen holder. factured by Key Transducers, Inc., Sterling Heights, MI.
G 137 – 97 (2003)
9.2 Test Conditions—The recommended conditions are the horizontally by adjusting the height of the lever arm angle
standard laboratory atmosphere of 23 6 2°C (73.4 6 3.6°F) adjusting rod. The required load can be applied by other
and 50 6 5% relative humidity. mechanisms.
10.9 Frictionaltorquevaluesproducedbythemachineitself
10. Procedure
(should not be more than 60.05 Nm) should be zeroed as
follows:
10.1 Clean the counterface ring using mild soap and water
10.9.1 The block-on-ring tester is turned on without any
so as to remove bulk dirt and corrosion-inhibiting oil. After-
load being applied to the specimen. This gives a stable torque
wards, clean the counterface ring in an ultrasonic acetone bath
readingwhichshouldbezeroed.Afterzeromarkerisobtained,
for 2 h (43 kHz 95 W) to remove the remaining contaminants.
load may be applied to run the test.
Allow the ring to dry completely. Handle the ring from this
10.10 Bring the lever arm angle adjusting rod gently into
point on with lint-free cotton gloves.
contact with the
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