ASTM G77-98

Standard Test Method for Ranking Resistance of Materials to Sliding Wear Using Block-on-Ring Wear Test

SCOPE
1.1 This test method covers laboratory procedures for determining the resistance of materials to sliding wear. The test utilizes a block-on-ring friction and wear testing machine to rank pairs of materials according to their sliding wear characteristics under various conditions.  
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 various lubricants, liquids, or gaseous atmospheres, as desired, to simulate service conditions. Rotational speed and load can also be varied to better correspond to service requirements.
1.3 Wear test results are reported as the volume loss in cubic millimetres for both the block and ring. Materials of higher wear resistance will have lower volume loss.
1.4 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.

General Information

• Status: Historical
• Publication Date: 09-Oct-1998
• ICS: 77.040.10 - Mechanical testing of metals
• Technical Committee: G02 - Wear and Erosion
• Drafting Committee: G02.40 - Non-Abrasive Wear

Relations

• Replaced By: ASTM G77-05 - Standard Test Method for Ranking Resistance of Materials to Sliding Wear Using Block-on-Ring Wear Test
• Effective Date: 01-May-2005
• Referred By: ASTM G115-10(2018) - Standard Guide for Measuring and Reporting Friction Coefficients
• Effective Date: 10-Oct-1998
• Referred By: ASTM G137-97(2017) - Standard Test Method for Ranking Resistance of Plastic Materials to Sliding Wear Using a Block-On-Ring Configuration
• Effective Date: 10-Oct-1998
• Referred By: ASTM G176-03(2017) - Standard Test Method for Ranking Resistance of Plastics to Sliding Wear Using Block-on-Ring Wear Test—Cumulative Wear Method
• Effective Date: 10-Oct-1998

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:G77–98
Standard Test Method for
Ranking Resistance of Materials to Sliding Wear Using
Block-on-Ring Wear Test
ThisstandardisissuedunderthefixeddesignationG77;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This test method covers laboratory procedures for de- 3.1 Definition:
termining the resistance of materials to sliding wear. The test 3.1.1 wear—damage to a solid surface, generally involving
utilizes a block-on-ring friction and wear testing machine to progressive loss of material, due to relative motion between
rank pairs of materials according to their sliding wear charac- that surface and a contacting substance or substances.
teristics under various conditions. 3.1.2 Foradditionaldefinitionspertinenttothistestmethod,
1.2 An important attribute of this test is that it is very see TerminologyG40.
flexible.Anymaterialthatcanbefabricatedinto,orappliedto,
4. Summary of Test Method
blocks and rings can be tested. However, the interlaboratory
testinghasbeenlimitedtometals.Thus,thepotentialmaterials 4.1 Atest block is loaded against a test ring that rotates at a
given speed for a given number of revolutions. Block scar
combinations are endless. In addition, the test can be run with
various lubricants, liquids, or gaseous atmospheres, as desired, volume is calculated from the block scar width, and ring scar
volume is calculated from ring weight loss. The friction force
to simulate service conditions. Rotational speed and load can
also be varied to better correspond to service requirements. required to keep the block in place is continuously measured
during the test with a load cell. These data, combined with
1.3 Weartestresultsarereportedasthevolumelossincubic
millimetres for both the block and ring. Materials of higher normal force data, are converted to coefficient of friction
values and reported.
wear resistance will have lower volume loss.
1.4 This standard does not purport to address the safety
5. Significance and Use
concerns, if any, associated with its use. It is the responsibility
5.1 The significance of this test method in any overall
of the user of this standard to establish appropriate safety and
measurement program directed toward a service application
health practices and determine the applicability of regulatory
will depend on the relative match of test conditions to the
limitations prior to use.
conditions of the service application.
2. Referenced Documents
5.2 This test method seeks only to prescribe the general test
procedure and method of calculating and reporting data. The
2.1 ASTM Standards:
D2714 Test Method for Calibration and Operation of the choice of test operating parameters is left to the user. A fixed
amount of sliding distance must be used because wear is
Falex Block-on-Ring Friction and Wear Testing Machine
E122 Practice for Choice of Sample Size to Estimate a usually non-linear with distance in this test.
Measure of Quality for a Lot or Process
6. Apparatus and Materials
E177 Practice for Use of the Terms Precision and Bias in
6.1 Test Schematic—Aschematic of the block-on-ring wear
ASTM Test Methods
test geometry is shown in Fig. 1. Acceptable testing machines
E691 Practice for Conducting an Interlaboratory Study to
are shown in Appendix X1.
Determine the Precision of a Test Method
6.2 Test Ring—A typical test ring is shown in Fig. 2. The
G40 Terminology Relating to Wear and Erosion
test ring must have an outer diameter of 34.996 0.025 mm
(1.377 6 0.001 in.) with an eccentricity between the inner and
This test method is under the jurisdiction of ASTM Committee G-2 on Wear
andErosionandisthedirectresponsibilityofSubcomitteeG02.40onNon-Abrasive
Wear.
Current edition approved Oct. 10, 1998. Published January 1999. Originally Several machines, including the current Falex Model I and the older Dow
published as G77–83. Last previous edition G77–97. CorningLFW-1machines,havebeenfoundsatisfactoryforthepurposesofthistest.
Annual Book of ASTM Standards, Vol 05.02. These models may differ in lever arm ratio, load range, speed control (variable or
Annual Book of ASTM Standards, Vol 14.02. fixed), speed range, and type of friction measuring device. Suitable machines may
Annual Book of ASTM Standards, Vol 03.02. be purchased from Falex Corporation, 1020 Airpark Dr., Sugar Grove, IL 60554.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
G77–98
as desired, to augment the description of the wear surfaces.
Clean the block and the ring if necessary as in 9.1.
9.3 Demagnetizethemetalspecimensandferrousassembly.
Weigh the block and ring to the nearest 0.1 mg.
9.4 Measure the block width and ring diameter to the
nearest 0.05 mm (0.002 in.).
9.5 Clean the hemispherical block holder, ring shaft, and
lubricant reservoir with trichloroethane.
9.6 Put the hemispherical block holder on the block.
9.7 Place the block in position on the machine and, while
FIG. 1 Test Schematic
holding the block in position, place the ring on the shaft and
lock the ring in place, using a torque wrench in accordance
with the requirements of the specific machine design.
outer surface of no greater than 0.00125 mm (0.0005 in.). For
9.8 Center the block on the ring while placing a light
couples where surface condition is not under study, it is
manual pressure on the lever arm to bring the block and ring
recommended that the outer diameter be a ground surface with
into contact. Be sure the edge of the block is parallel to the
a roughness of 0.152 to 0.305 µm (6 to 12 µin.) rms or center
edge of the ring and that the mating surfaces are perfectly
line average (CLA), in the direction of motion. However,
aligned. This is accomplished by making sure the specimen
alternate surface conditions may be evaluated in the test, as
holder is free during mounting so that the quarter segment can
desired. It should be kept in mind that surface condition can
properly seat itself. Release the pressure on the lever arm.
have an effect on sliding wear results.
9.9 One may choose either a preloading or a step-loading
6.3 Test Block—AtestblockisshowninFig.3.Blockwidth
procedure. Generally, preloading is chosen for variable speed
is 6.35+0.000,−0.025 mm (0.250+0.000,−0.001 in.). For
machines, while step-loading is chosen for fixed speed ma-
coupleswheresurfaceconditionisnotaparameterunderstudy,
chines in order to avoid an initial high wear transient. The
a ground surface with the grinding marks running parallel to
differences in the two procedures are indicated in 9.10-9.22.
thelongaxisoftheblockandaroughnessof0.102to0.203µm
9.10 Place the required weights on the load bale and adjust
(4 to 8 µin.) CLA in the direction of motion is recommended.
the lever arm in accordance with the requirements of the
However, other surface conditions may be evaluated as de-
specific machine design. Then remove the load by raising the
sired.
weights, if using the preloading procedure, or by removing the
6.4 Analytical Balance, capable of measuring to the nearest
weights if using the step-loading procedure.
0.1 mg.
9.11 If running a lubricated test, clean all components that
6.5 Optical device (or equivalent), with metric or inch-
will come in contact with lubricant; fill the lubricant reservoir
pound unit calibration, is also necessary so that scar width can
with lubricant to 6.4 mm (0.25 in.) above the lower surface of
be measured with a precision of 0.005 mm (0.0002 in.) or
the ring; rotate the ring several times.
equivalent.
9.12 Set the revolution counter to zero.
9.13 Gentlylowertheweights,applyingtherequiredload,if
7. Reagents
using the preloading procedure.
7.1 Trichloroethane.
9.14 If using a variable speed machine, turn on the machine
7.2 Methanol.
and slowly increase the power to the drive motor until the ring
startstorotate,recordingthe“static”frictionforce.Continueto
8. Preparation and Calibration of Apparatus
increase the rate of rotation to the desired rate. If using a fixed
8.1 Run the calibration procedure that is in Test Method
speed machine, simply turn on the machine.
D2714 to ensure good mechanical operation of the test
9.15 If using step-loading, start the machine with no
equipment.
weights, then gently add a 133-N (30-lbf) load every 200 rev
until the required test load is reached. Adjust the rate of
9. Procedure
rotationasneeded.Iftherequiredloadislessthan133N,apply
9.1 Clean the block and ring using a procedure that will
the load in one step.
remove any scale, oil film, or residue without damaging the
9.16 During the test, record the friction force, lubricant or
surface.
block temperature, as required, and, if desired, the vertical
9.1.1 For metals, the following procedure is recommended:
displacement of the block.
clean the block and ring in trichloroethane, ultrasonically, if
9.17 Stop the test manually or automatically after the
possible;amethanolrinsemaybeusedtoremoveanytracesof
desired number of revolutions.
trichloroethane residue. Allow the blocks and rings to dry
completely. Handle the block and ring with clean, lint-free
cotton gloves from this point on.
TheseinstructionsareappropriateforthemachinesshowninAppendixX1.The
9.2 Make surface texture and surface roughness measure-
instructions may be modified, as necessary, by the user to fit the requirements of
ments across the width of the block and the ring, as necessary.
alternate machine designs.
Note that a surface profile does not completely describe a
5,400 and 10 800 revolutions have been used for metals in interlaboratory test
surface topology. Scanning electron micrographs may be used, programs.
G77–98
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
9.18 A final “static” friction force may be measured with a 9.21 Measure the scar width on the test block in the center
variablespeedmachine.Leavingonthefullload,wait3min 6 and ;1 mm (0.04 in.) away from each edge. These measure-
10 s, then turn on the machine and slowly increase the power
ments shall be to the nearest 0.1 mm (0.004 in.). Record the
to the drive motor until the ring starts to rotate, recording the
average of the three readings. Sometimes oxidation debris or a
“static” final friction force. Then turn off the motor.
lip of plastically deformed material will extend over the edge
9.19 Remove the block and ring, clean, and reweigh to the
of the wear scar (Fig. 4). When measuring scar width, try to
nearest 0.1 mg. For metals use trichloroethane.
visually ignore this material or measure the scar width in an
9.20 Make surface roughness measurements and profilome-
area where this is not a problem.
ter traces across the width of the block and the ring as desired.
9.22 Tapered scars indicate improper block alignment dur-
Atrace along the long axis of the block, through the wear scar,
ing testing. If the three width measurements on a given scar
is also useful to verify the scar depth and shape.
have a coefficient of variation of greater than 10%, the test
shall be declared invalid.
On some of the old test machines, it is possible for the block to move back and
forth slightly, increasing the apparent size of the wear scar. This is generally not a
10. Calculation
problem on the more rigid Falex machines. If this problem is suspected, a
profilometer trace through the wear scar will verify whether or not the scar shape
10.1 Calculation of Block Scar Volume:
corresponds to the curvature of the ring.
G77–98
FIG. 3 Test Block
A. A good rectangular scar with straight edges.
B. The center of the scar is curved because the block was crowned. Also, debris covers the center left edge of the scar. Ordinarily, the debris should be visually ig-
nored, but in this case scar curvature makes this too difficult. The test should be rerun.
C. Severe galling resulted in jagged scar edges and a lip of plastically deformed material along the right side of the scar. The raised lip of material is excluded from
the scar measurement. The cross hair should be run to a visual average of the jagged edge, not to the point of a zigzag.
D. Tapered scar with jagged edges. This scar is too tapered (coefficient of variation > 10 %); therefore, the test should be rerun.
FIG. 4 Block Scars
G77–98
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 0.9301 3.84 1.7196
0.32 0.0010 1.03 0.0331 1.74 0.1595 2.44 0.4402 3.14 0.9391 3.85 1.7331
0.33 0.0011 1.04 0.0340 1.75 0.1623 2.45 0.4456 3.15 0.9481 3.86 1.7467
0.34 0.0012 1.05 0.0350 1.76 0.1651 2.46 0.4511 3.16 0.9572 3.87 1.7603
0.35 0.0013 1.06 0.0360 1.77 0.1679 2.47 0.4567 3.17 0.9663 3.88 1.7740
0.36 0.0014 1.07 0.0371 1.78 0.1708 2.48 0.4622 3.18 0.9755 3.89 1.7878
0.37 0.0015 1.08 0.0381 1.79 0.1737 2.49 0.4679 3.19 0.9847 3.90 1.8017
0.38 0.0017 1.09 0.0392 1.80 0.1766 2.50 0.4735 3.20 0.9940 3.91 1.8156
0.39 0.0018 1.10 0.0403 1.81 0.1796 2.51 0.4792 3.21 1.0034 3.92 18296
0.40 0.0019 1.11 0.0414 1.82 0.1826 2.52 0.4850 3.22 1.0128 3.93 1.9437
0.41 0.0021 1.12 0.0425 1.83 0.1856 2.53 0.4908 3.23 1.0223 3.94 1.8578
0.42 0.0022 1.13 0.0437 1.84 0.1887 2.54 0.4966 3.24 1.0318 3.95 1.8720
0.43 0.0024 1.13 0.0448 1.85 0.1917 2.55 0.5025 3.25 1.0414 3.96 1.8863
0.44 0.0026 1.15 0.0460 1.86 0.1949 2.56 0.5085 3.26 1.0511 3.97 1.9007
0.45 0.0028 1.16 0.0472 1.87 0.1980 2.57 0.5145 3.27 10608 3.98 1.9151
0.46 0.0029 1.17 0.0485 1.88 0.2012 2.58 0.5205 3.28 1.0706 3.99 1.9296
0.47 0.0031 1.18 0.0497 1.89 0.2045 2.59 0.5266 3.29 1.0804
0.48 0.0033 1.19 0.0510 1.90 0.2077 2.60 0.5327 3.30 1.0903 4.00 1.9442
0.49 0.0036 1.20 0.0523 1.91 0.2110 2.61 0.5389 3.31 1.1003 4.01 1.9589
0.50 0.0038 1.21 0.0536 1.92 0.2144 2.62 0.5451 3.32 1.1103 4.02 1.9736
0.51 0.0040 1.22 0.0550 1.93 0.2177 2.63 0.5514 3.33 1.1204 4.03 1.9884
0.52 0.0043 1.23 0.0563 1.94 0.2211 2.64 0.5577 3.34 1.1305 4.04 2.0033
0.53 0.0045 1.24 0.0577 1.95 0.2246 2.65 0.5641 3.35 1.1407
...