ASTM G176-03(2017)
(Test Method)Standard Test Method for Ranking Resistance of Plastics to Sliding Wear Using Block-on-Ring Wear Test—Cumulative Wear Method
Standard Test Method for Ranking Resistance of Plastics to Sliding Wear Using Block-on-Ring Wear Test—Cumulative Wear Method
SIGNIFICANCE AND USE
5.1 The significance of this test method in any overall measurement program directed toward a service application will depend on the relative match of test conditions to the conditions of the service application.
5.2 This test method prescribes the test procedure and method of calculating and reporting data for determining the sliding wear resistance of plastics, using cumulative volume loss.
5.3 The intended use of this test is for coarse screening of plastics in terms of their resistance to sliding wear.
SCOPE
1.1 This test method covers laboratory procedures for determining the resistance of plastics to sliding wear. The test utilizes a block-on-ring friction and wear testing machine to rank plastics according to their sliding wear characteristics against metals or other solids.
1.2 An important attribute of this test is that it is very flexible. Any material that can be fabricated into, or applied to, blocks and rings can be tested. Thus, the potential materials combinations are endless. In addition, the test can be run with different gaseous atmospheres and elevated temperatures, as desired, to simulate service conditions.
1.3 Wear test results are reported as the volume loss in cubic millimetres for the block and ring. Materials of higher wear resistance will have lower volume loss.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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, 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.
General Information
Relations
Standards Content (Sample)
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.
Designation: G176 − 03 (Reapproved 2017)
Standard Test Method for
Ranking Resistance of Plastics to Sliding Wear Using
Block-on-Ring Wear Test—Cumulative Wear Method
This standard is issued under the fixed designation G176; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers laboratory procedures for de-
D618Practice for Conditioning Plastics for Testing
termining the resistance of plastics to sliding wear. The test
D2714Test Method for Calibration and Operation of the
utilizes a block-on-ring friction and wear testing machine to
Falex Block-on-Ring Friction and Wear Testing Machine
rank plastics according to their sliding wear characteristics
E122PracticeforCalculatingSampleSizetoEstimate,With
against metals or other solids.
Specified Precision, the Average for a Characteristic of a
1.2 An important attribute of this test is that it is very
Lot or Process
flexible.Anymaterialthatcanbefabricatedinto,orappliedto,
E177Practice for Use of the Terms Precision and Bias in
blocks and rings can be tested. Thus, the potential materials ASTM Test Methods
combinations are endless. In addition, the test can be run with E691Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
different gaseous atmospheres and elevated temperatures, as
desired, to simulate service conditions. G40Terminology Relating to Wear and Erosion
G77Test Method for Ranking Resistance of Materials to
1.3 Weartestresultsarereportedasthevolumelossincubic
Sliding Wear Using Block-on-Ring Wear Test
millimetres for the block and ring. Materials of higher wear
resistance will have lower volume loss.
3. Terminology
1.4 The values stated in SI units are to be regarded as the 3.1 Definitions:
3.1.1 wear—damage to a solid surface, generally involving
standard. The values given in parentheses are for information
progressive loss of material, due to relative motion between
only.
that surface and a contacting substance or substances. G40
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
4.1 A test plastic block is loaded against a metal test ring
priate safety, health, and environmental practices and deter-
that rotates at a given speed for a given number of revolutions.
mine the applicability of regulatory limitations prior to use.
Blockscarvolumeiscalculatedfromtheblockscarwidth.The
1.6 This international standard was developed in accor-
friction force required to keep the block in place may be
dance with internationally recognized principles on standard-
continuously measured during the test with a load cell. When
ization established in the Decision on Principles for the
this is done, the friction force data are combined with normal
Development of International Standards, Guides and Recom-
force data to obtain values for the coefficient of friction and
mendations issued by the World Trade Organization Technical
reported.
Barriers to Trade (TBT) Committee.
5. Significance and Use
5.1 The significance of this test method in any overall
measurement program directed toward a service application
will depend on the relative match of test conditions to the
conditions of the service application.
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-
Abrasive Wear. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2017. Published December 2017. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2003. Last previous edition approved in 2009 as G176–03 (2009). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/G0176-03R17. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G176 − 03 (2017)
5.2 This test method prescribes the test procedure and prior to testing in accordance with Procedure A of Practice
method of calculating and reporting data for determining the D618 for those samples where conditioning is required.
sliding wear resistance of plastics, using cumulative volume
9.2 The recommended test conditions are the standard
loss.
laboratory atmosphere of 23 6 2°C (73.4 6 3.6°F) and 50 6
5.3 The intended use of this test is for coarse screening of
5% relative humidity.
plastics in terms of their resistance to sliding wear.
9.3 Clean the ring using a procedure that will remove any
scale, oil film, or residue without damaging the surface. The
6. Apparatus and Test Specimens
following procedure is recommended: clean the ring in a
6.1 Test Schematic—Aschematic of the block-on-ring wear
suitable solvent, ultrasonically, if possible; a methanol rinse
testgeometryisshowninFig.1.Inthefigure,thefrictionload
maybeusedtoremoveanytracesofsolventresidue.Allowthe
cell is enlarged.
rings to dry completely. Handle the ring with clean, lint-free
6.2 Test Ring—AtypicaltestringisshowninFig.2.Thetest
cotton gloves from this point on.
ring must have an outer diameter of 34.99 6 0.025 mm (1.377
9.4 For the plastic block, the following cleaning procedure
6 0.001 in.) with an eccentricity between the inner and outer
isrecommended:Cleantheplasticblockwithmethanol.Allow
surfaces of no greater than 0.00125 mm (0.0005 in.). For
the blocks to dry completely.After cleaning, handle the block
couples where surface condition is not under study, it is
with clean, lint-free cotton gloves. Other procedures may be
recommended that the outer diameter be a ground surface with
used provided they do not affect the plastic. If an application
a roughness of 0.152 to 0.305 µm (6 to 12 µin.) rms or center
understudyusesaplasticinthemoldedcondition,itisadvised
line average (CLA), in the direction of motion. However,
to test a block with the test surface in the molded condition.
alternate surface conditions may be evaluated in the test, as
The wear of a molded surface may be different from the wear
desired. It should be kept in mind that surface condition can
of a machined surface.
have an effect on sliding wear results.
NOTE 1—Acommonly used test ring is a carburized 4620 steel having
9.5 Make surface texture and surface roughness measure-
a hardness of 60 HRC or higher.
ments across the width of the ring, as necessary. Note that a
6.3 Test Block—AtestblockisshowninFig.3.Blockwidth
surface profile does not completely describe a surface topol-
is 6.35 + 0.000, −0.025 mm (0.250 + 0.000, −0.001 in.).
ogy.Scanningelectronmicrographsmaybeused,asdesired,to
augment the description of the wear surfaces. Clean the ring
6.4 Optical Device (or equivalent), with metric or English
again, if necessary, as in 9.3.
unit calibration, is also necessary so that scar width can be
measured with a precision of 0.01 mm (0.0004 in.) or equiva-
9.6 Demagnetize the ring and ferrous assembly.
lent.
9.7 Measure the block width and ring diameter to the
7. Reagents nearest 0.025 mm (0.001 in.).
7.1 Reagents may include the following:
9.8 Clean the self-aligning block holder, ring shaft, and
surrounding fixtures with solvent.
NOTE 2—Organic cleaners should be used with caution as they may
react with the plastic being tested.
9.9 Put the self-aligning block holder on the block.Apply a
7.1.1 Methanol. thin layer of lubricant to the self-aligning holder. Use of a
7.1.2 Eye Glass Cleaner.
non-migrating product is suggested.
9.10 Place the block in position on the machine and, while
8. Preparation and Calibration of Apparatus
holding the block in position, place the ring on the shaft and
8.1 Run the calibration procedure that is in Test Method
lock the ring in place, using a method in accordance with the
D2714 to ensure good mechanical operation of the test
requirements of the specific machine design.
equipment.
9.11 Center the block on the ring while placing a light
9. Procedure
manual pressure on the lever arm to bring the block and ring
into contact. Be sure the edge of the block is parallel to the
9.1 Condition the test specimens at 23 6 2°C (73.4 6
3.6°F) and 50 6 5% relative humidity for not less than 40 h edge of the ring and that the mating surfaces are perfectly
aligned. This is accomplished by making sure the specimen
holder is free during mounting so that the quarter segment can
properly seat itself. Release the pressure on the lever arm.
9.12 Place the required weights on the load bale and adjust
the lever arm in accordance with the requirements of the
specific machine design to provide a load of 44.3 N (10 lbf) at
the block/ring interface. Then remove the load by raising the
weights.
9.13 Set the revolution counter to zero.
FIG. 1 Test Schematic 9.14 Gently lower the weights to apply the required load.
G176 − 03 (2017)
NOTE 1—The outer diameter and concentricity with the inner diameter are the only critical parameters. The inner diameter is optional depending on
machine design. The inside diameter taper shown fits a number of standard machines.
FIG. 2 Test Ring
9.15 If using a variable speed machine, turn on the machine 9.19 Remove the block and ring and clean. For metals, use
and slowly increase the power to the drive motor until the ring a suitable solvent. For plastics, remove loose debris with a dry
starts to rotate, and record the “static” friction force. Continue
soft brush.
to increase the rate of rotation to 200 rpm. If using a fixed
9.20 Make surface roughness measurements and profilome-
speed machine, simply turn on the machine.
ter traces across the width of the block and the ring as desired.
9.16 During the test, record the friction force.
Atracealongthelongaxisoftheblock,throughthewearscar,
9.17 Stop the test manually or automatically after 240000
is also useful to verify the scar depth and shape.
revolutions (20 h).
9.21 Measure the scar width on the test block in the center
9.18 Afinal “static” friction force may be measured with a
and ~1 mm (0.04 in.) away from each edge. These measure-
variablespeedmachine.Leavingonthefullload,wait3min 6
ments shall be to the nearest 0.01 mm (0.0004 in.). Record the
10 s, then turn on the machine and slowly increase the power
average of the three readings. Sometimes a lip of plastically
to the drive motor until the ring starts to rotate, recording the
deformed material will extend over the edge of the wear scar.
final “static” friction force. Then turn off the motor.
G176 − 03 (2017)
FIG. 3 Test Block
Whenmeasuringscarwidth,trytovisuallyignorethismaterial ringmassloss
volumeloss 5 (2)
or measure the scar width in an area where this is not a ringdensity
problem.
10.3.1 Iftheringgainsmassduringthetest,thevolumeloss
9.22 Tapered scars indicate improper block alignment dur-
is reported as zero with a notation that weight gain occurred.
ing testing. If the three width measurements on a given scar
Ring mass loss can be affected by transfer of the plastic to the
have a coefficient of variation of greater than 10%, the test
metal surface. If plastic transfer to the ring is obvious, then a
shall be declared invalid. For further discussion of measure-
ringscarvolumeshouldnotbecalculatedfromtheweightloss
ment problems see 9.21, 9.22, and Fig. 4 in Test Method G77.
measurement, but a notation should be made that plastic
transfer occurred. If there are obvious signs of abrasion of the
10. Calculation
ring surface, such as scratches or grooving, this should also be
noted. In this case profilometry may be used to measure
10.1 Calculation of Block Scar Volume:
material loss.
10.1.1 Block scar volume may be derived from block scar
width by using Table 1 (applicable only when ring diameter is
11. Report
34.99 6 0.025 mm (1.377 6 0.001 in.) and scar length (block
width) is 6.35 + 0.000, −0.025 mm (0.250 + 0.000, −0.001
11.1 Report any unusual event or an overload shutoff of the
in.)).
machine(onsomemachinesitispossibletohaveanautomatic
10.1.2 The preferred method of calculating block scar
shutoff at a preset frictional load). If the machine malfunctions
volume is by using the formula shown in Fig. 4. This formula
oratestblockhasataperedscar,thedatashallnotbeused,and
may be programmed on a calculator or computer.
the test shall be rerun.
10.1.3 Block scar volume is not calculated generally from
11.2 Report the following:
block mass loss because block mass is subject to effects of
11.2.1 Test Parameters:
materialtransfer.Keepingthisinmind,blockmasslossmaybe
11.2.1.1 Block material,
interpreted semi-quantitatively in a comparative evaluation of
11.2.1.2 Ring material and hardness (whenever applicable),
variousmaterialcouples.Iftheblockscarcannotbeaccurately
11.2.1.3 Ring and block initial surface roughness, and
measured following 9.21, a scar volume should not be
11.2.1.4 Number of replicates.
calculated, but a notation made of the problem, for example,
11.2.2 Results—Report the average and the coefficient of
material transfer, plastic deformation, and so forth.
variation of the following (the coefficient of variation is the
10.2 Calculate coefficient of friction values from friction
standard deviation divided by the average; it is expressed as a
force values as follows:
percent).
11.2.2.1 Block scar width, mm,
F
ƒ 5 (1) 3
11.2.2.2 Block scar volume, mm , calculated from scar
W
width, and
where:
11.2.2.3 Ambient conditions, if other than normal labora-
ƒ = coefficient of friction,
tory conditions.
F = measured friction force, N (lbf), and
11.2.3 Reporting Optional:
W = applied load, 44.3 N (10 lbf).
11.2.3.1 Final surface roughness of block and ring,
10.3 Calculate ring volume loss as follows: 11.2.3.2 Ring heat treatment, and
G176 − 03 (2017)
TABLE 1 Block Scar Widths and Volumes for Blocks 6.35-mm Wide Mated Against Rings 34.99 mm in Diameter
Block Scar Block Scar
Volume Width Volume Width Volume Volume Width Volume Width Volume
Width Width
3 3 3 3 3 3
(mm ) (mm) (mm ) (mm) (mm ) (mm ) (mm) (mm ) (mm) (mm )
(mm) (mm)
0.30 0.0008 1.01 0.0312 1.72 0.1541 2.42 0.4295 3.12 0.9212 3.83 1.7062
0.31 0.0009 1.02 0.0321 1.73 0.1568 2.43 0.4348 3.13
...
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