ASTM G77-05(2010)

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

SIGNIFICANCE AND USE
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 seeks only to prescribe the general test procedure and method of calculating and reporting data. The choice of test operating parameters is left to the user. A fixed amount of sliding distance must be used because wear is usually non-linear with distance in this 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. However, the interlaboratory testing has been limited to metals. 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 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 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: 31-Mar-2010
• ICS: 77.040.10 - Mechanical testing of metals
• Technical Committee: G02 - Wear and Erosion
• Drafting Committee: G02.40 - Non-Abrasive Wear

Relations

• Replaces: ASTM G77-05e1 - Standard Test Method for Ranking Resistance of Materials to Sliding Wear Using Block-on-Ring Wear Test
• Effective Date: 01-Apr-2010
• 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: 01-Apr-2010
• Referred By: ASTM G115-10(2018) - Standard Guide for Measuring and Reporting Friction Coefficients
• Effective Date: 01-Apr-2010
• 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: 01-Apr-2010

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 − 05 (Reapproved 2010)
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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope E177Practice for Use of the Terms Precision and Bias in
ASTM Test Methods
1.1 This test method covers laboratory procedures for de-
E691Practice for Conducting an Interlaboratory Study to
termining the resistance of materials to sliding wear. The test
Determine the Precision of a Test Method
utilizes a block-on-ring friction and wear testing machine to
G40Terminology Relating to Wear and Erosion
rank pairs of materials according to their sliding wear charac-
teristics under various conditions.
3. Terminology
1.2 An important attribute of this test is that it is very
3.1 Definitions:
flexible.Anymaterialthatcanbefabricatedinto,orappliedto,
3.1.1 wear—damage to a solid surface, generally involving
blocks and rings can be tested. Thus, the potential materials
progressive loss of material, due to relative motion between
combinations are endless. However, the interlaboratory testing
that surface and a contacting substance or substances.
hasbeenlimitedtometals.Inaddition,thetestcanberunwith
3.1.2 Foradditionaldefinitionspertinenttothistestmethod,
various lubricants, liquids, or gaseous atmospheres, as desired,
see Terminology G40.
to simulate service conditions. Rotational speed and load can
also be varied to better correspond to service requirements.
4. Summary of Test Method
1.3 The values stated in SI units are to be regarded as the
4.1 Atest block is loaded against a test ring that rotates at a
standard. The values given in parentheses are for information
given speed for a given number of revolutions. Block scar
only.Wear test results are reported as the volume loss in cubic
volume is calculated from the block scar width, and ring scar
millimetres for both the block and ring. Materials of higher
volume is calculated from ring weight loss. The friction force
wear resistance will have lower volume loss.
required to keep the block in place is continuously measured
1.4 This standard does not purport to address all of the
during the test with a load cell. These data, combined with
safety concerns, if any, associated with its use. It is the
normal force data, are converted to coefficient of friction
responsibility of the user of this standard to establish appro-
values and reported.
priate safety and health practices and determine the applica-
5. Significance and Use
bility of regulatory limitations prior to use.
5.1 The significance of this test method in any overall
2. Referenced Documents
measurement program directed toward a service application
will depend on the relative match of test conditions to the
2.1 ASTM Standards:
conditions of the service application.
D2714Test Method for Calibration and Operation of the
Falex Block-on-Ring Friction and Wear Testing Machine
5.2 This test method seeks only to prescribe the general test
E122PracticeforCalculatingSampleSizetoEstimate,With
procedure and method of calculating and reporting data. The
Specified Precision, the Average for a Characteristic of a
choice of test operating parameters is left to the user. A fixed
Lot or Process
amount of sliding distance must be used because wear is
usually non-linear with distance in this test.
6. Apparatus and Materials
This test method is under the jurisdiction of ASTM Committee G02 on Wear
and Erosion and is the direct responsibility of G02.40 on Non-Abrasive Wear.
6.1 Test Schematic—Aschematic of one possible block-on-
Current edition approved April 1, 2010. Published May 2010. Originally
ε1
ring wear test geometry is shown in Fig. 1.
approved in 1983. Last previous edition approved in 2005 as G77–05 . DOI:
10.1520/G0077-05R10.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Several machines have been found satisfactory for the purposes of this test.
Standards volume information, refer to the standard’s Document Summary page on These models may differ in lever arm ratio, load range, speed control (variable or
the ASTM website. fixed), speed range, and type of friction measuring device.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G77 − 05 (2010)
9. Procedure
9.1 Clean the block and ring using a procedure that will
remove any scale, oil film, or residue without damaging the
surface.
9.1.1 For metals, the following procedure is recommended:
clean the block and ring in a non-chlorine containing solvent,
ultrasonically, if possible; a methanol rinse may be used to
remove any traces of solvent residue. Allow the blocks and
rings to dry completely. Handle the block and ring with clean,
lint-free cotton gloves from this point on.
9.2 Make surface texture and surface roughness measure-
ments across the width of the block and the ring, as necessary.
Note that a surface profile does not completely describe a
surface topology. Scanning electron micrographs may be used,
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 0.025 mm (0.001 in.).
FIG. 1 Test Schematic
9.5 Clean the self-aligning block holder, ring shaft, and
lubricant reservoir with solvent.
6.2 Test Ring—AtypicaltestringisshowninFig.2.Thetest
9.6 Put the self-aligning block holder on the block.
ring must have an outer diameter of 34.99 6 0.025 mm (1.377
6 0.001 in.) with an eccentricity between the inner and outer 9.7 Place the block in position on the machine and, while
surface of no greater than 0.00125 mm (0.0005 in.). For
holding the block in position, place the ring on the shaft and
couples where surface condition is not under study, it is lock the ring in place, using a test method in accordance with
recommended that the outer diameter be a ground surface with
the requirements of the specific machine design.
a roughness of 0.152 to 0.305 µm (6 to 12 µin.) rms or center
9.8 Center the block on the ring while placing a light
line average (CLA), in the direction of motion. However,
manual pressure on the lever arm to bring the block and ring
alternate surface conditions may be evaluated in the test, as
into contact. Be sure the edge of the block is parallel to the
desired. It should be kept in mind that surface condition can
edge of the ring and that the mating surfaces are perfectly
have an effect on sliding wear results.
aligned. This is accomplished by making sure the specimen
6.3 Test Block—AtestblockisshowninFig.3.Blockwidth
holder is free during mounting so that the self-aligning block
is 6.35+0.000,−0.025 mm (0.250+0.000,−0.001 in.). For
holder can properly seat itself. Release the pressure on the
coupleswheresurfaceconditionisnotaparameterunderstudy,
lever arm.
a ground surface with the grinding marks running parallel to
9.9 One may choose either a preloading or a step-loading
thelongaxisoftheblockandaroughnessof0.102to0.203µm
procedure. Generally, preloading is chosen for variable speed
(4 to 8 µin.) CLA in the direction of motion is recommended.
machines, while step-loading is chosen for fixed speed ma-
However, other surface conditions may be evaluated as de-
chines in order to avoid an initial high wear transient. The
sired.
differences in the two procedures are indicated in 9.10 – 9.22.
6.4 Analytical Balance, capable of measuring to the nearest
9.10 Place the required weights on the load bale and adjust
0.1 mg.
the lever arm in accordance with the requirements of the
6.5 Optical Device (or equivalent), with metric or inch-
specific machine design. Then remove the load by raising the
pound unit calibration, is also necessary so that scar width can
weights, if using the preloading procedure, or by removing the
be measured with a precision of 0.005 mm (0.0002 in.) or
weights if using the step-loading procedure.
equivalent.
9.11 If running a lubricated test, clean all components that
7. Reagents
will come in contact with lubricant; fill the lubricant reservoir
7.1 Methanol. with lubricant to 6.4 mm (0.25 in.) above the lower surface of
the ring; rotate the ring several times.
8. Preparation and Calibration of Apparatus
9.12 Set the revolution counter to zero.
8.1 Run the calibration procedure that is in Test Method
D2714 to ensure good mechanical operation of the test 9.13 Gentlylowertheweights,applyingtherequiredload,if
equipment. using the preloading procedure.
G77 − 05 (2010)
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
FIG. 3 Test Block
9.14 If using a variable speed machine, turn on the machine 9.17 Stop the test manually or automatically after the
and slowly increase the power to the drive motor until the ring desired number of revolutions.
startstorotate,recordingthe“static”frictionforce.Continueto
9.18 Afinal “static” friction force may be measured with a
increase the rate of rotation to the desired rate. If using a fixed
variablespeedmachine.Leavingonthefullload,wait3min 6
speed machine, simply turn on the machine.
10 s, then turn on the machine and slowly increase the power
9.15 If using step-loading, start the machine with no to the drive motor until the ring starts to rotate, recording the
weights, then gently add a 133-N (30-lbf) load every 200 rev “static” final friction force. Then turn off the motor.
until the required test load is reached. Adjust the rate of
9.19 Remove the block and ring, clean, and reweigh to the
rotationasneeded.Iftherequiredloadislessthan133N,apply
nearest 0.1 mg.
the load in one step.
9.16 During the test, record the friction force, lubricant or
block temperature, as required, and, if desired, the vertical
5400 and 10 800 revolutions have been used for metals in interlaboratory test
displacement of the block. programs.
G77 − 05 (2010)
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
ignored, 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
9.20 Make surface roughness measurements and profilome- 9.22 Tapered scars indicate improper block alignment dur-
ter traces across the width of the block and the ring as desired. ing testing. If the three width measurements on a given scar
Atrace along the long axis of the block, through the wear scar, have a coefficient of variation of greater than 10%, the test
is also useful to verify the scar depth and shape. shall be declared invalid.
9.21 Measure the scar width on the test block in the center
10. Calculation
and ;1 mm (0.04 in.) away from each edge. These measure-
10.1 Calculation of Block Scar Volume:
ments shall be to the nearest 0.025 mm (0.001 in.). Record the
10.1.1 Block scar volume may be derived from block scar
average of the three readings. Sometimes oxidation debris or a
width by using Table 1 (applicable only when ring diameter is
lip of plastically deformed material will extend over the edge
34.99 6 0.025 mm (1.377 6 0.001 in.) and scar length (block
of the wear scar (Fig. 4). When measuring scar width, try to
width) is 6.35 + 0.000, −0.025 mm (0.250 + 0.000, −0.001
visually ignore this material or measure the scar width in an
in.)).
area where this is not a problem.
10.1.2 The preferred method of calculating block scar
volume is by using the formula shown in Fig. 5. This formula
may be programmed on a calculator or computer.
On some of the old test machines, it is possible for the block to move back and
10.1.3 Block scar volume is not calculated generally from
forth slightly, increasing the apparent size of the wear scar. If this problem is
block mass loss because block mass is subject to effects of
suspected, a profilometer trace through the wear scar will verify whether or not the
scar shape corresponds to the curvature of the ring. materials transfer, generation of oxide films, or penetration of
G77 − 05 (2010)
θ
t = block width, mm Scar Width
= b5D sin
D t
r = radius of ring, mm Scar volume
5 sθ 2 sin θd
D =2r = diameter of ring, mm
b
b = average scar width, mm where θ
= 2sin.
D
θ = sector angle in radians
D t b b
d = scar depth, mm [ Scar Volume
21 21
5 2sin 2sin 2sin
F S DG
8 D D
FIG. 5 Block Scar Volume Based on the Width of the Scar
or combinations thereof. If material transfer to the ring is obvious, then a
the material by the lubricant. Keeping in mind the above
ring scar volume should not be calculated from the weight loss
factors, block mass loss may be interpreted semiquantitatively
measurement, but a notation should be made that material transfer
in a comparative evaluation of various material couples. If the
occurred.
block scar cannot be accurately measured following 9.21 and
the guidance in Fig. 4, a scar volume should not be calculated,
11. Report
but a notation made of the problem; for example, material
11.1 Report any unusual event or an overload shutoff of the
transfer, plastic deformation, and so forth.
machine(onsomemachinesitispossibletohaveanautomatic
10.2 Calculate coefficient of friction values from friction
shutoff at a preset frictional load). If the machine malfunctions
force values as follows:
oratestblockhasataperedscar,thedatashallnotbeused,and
f 5 F/W (1)
the test shall be rerun.
11.2 Report the following:
where:
11.2.1 Test Parameters:
f = coefficient of friction
11.2.1.1 Block material and hardness (whenever
F = measured friction force, N (lbf), and
applicable),
W
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