ASTM G77-17 Standard Test Method for Ranking Resistance of Materials to Sliding Wear Using Block-on-Ring Wear Test.pdf

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1、Designation: G77 17Standard Test Method forRanking Resistance of Materials to Sliding Wear UsingBlock-on-Ring Wear Test1This standard is issued under the fixed designation G77; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the ye

2、ar of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers laboratory procedures for de-termining the resistance of materials to sliding wear. The test

3、utilizes a block-on-ring friction and wear testing machine torank pairs of materials according to their sliding wear charac-teristics under various conditions.1.2 An important attribute of this test is that it is veryflexible.Any material that can be fabricated into, or applied to,blocks and rings c

4、an be tested. Thus, the potential materialscombinations are endless. However, the interlaboratory testinghas been limited to metals. In addition, the test can be run withvarious lubricants, liquids, or gaseous atmospheres, as desired,to simulate service conditions. Rotational speed and load canalso

5、be varied to better correspond to service requirements.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly. Wear test results are reported as the volume loss in cubicmillimetres for both the block and ring. Materials of higherw

6、ear resistance will have lower volume loss.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulato

7、ry limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organ

8、ization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D2714 Test Method for Calibration and Operation of theFalex Block-on-Ring Friction and Wear Testing MachineE122 Practice for Calculating Sample Size to Estimate, WithSpecified Precision, the Average for a C

9、haracteristic of aLot or ProcessE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodG40 Terminology Relating to Wear and Erosion3. Terminology3.1 Definitions:3.1.1 sliding wear, nwear

10、 due to the relative motion in thetangential plane of contact between two solid bodies.3.1.2 weardamage to a solid surface, generally involvingprogressive loss of material, due to relative motion betweenthat surface and a contacting substance or substances.3.1.3 For additional definitions pertinent

11、to this test method,see Terminology G40.4. Summary of Test Method4.1 A test block is loaded against a test ring that rotates at agiven speed for a given number of revolutions. Block scarvolume is calculated from the block scar width, and ring scarvolume is calculated from ring weight loss. The frict

12、ion forcerequired to keep the block in place is continuously measuredduring the test with a load cell. These data, combined withnormal force data, are converted to coefficient of frictionvalues and reported.5. Significance and Use5.1 The significance of this test method in any overallmeasurement pro

13、gram directed toward a service application1This test method is under the jurisdiction of ASTM Committee G02 on Wearand Erosion and is the direct responsibility of G02.40 on Non-Abrasive Wear.Current edition approved June 1, 2017. Published June 2017. Originallyapproved in 1983. Last previous edition

14、 approved in 2010 as G77 05 (2010). DOI:10.1520/G0077-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copy

15、right ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of Internati

16、onal Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1will depend on the relative match of test conditions to theconditions of the service application.5.2 This test method seeks only to prescribe the general testprocedure and m

17、ethod of calculating and reporting data. Thechoice of test operating parameters is left to the user. A fixedamount of sliding distance must be used because wear isusually non-linear with distance in this test.6. Apparatus and Materials6.1 Test SchematicA schematic of one possible block-on-ring wear

18、test geometry is shown in Fig. 1.36.2 Test RingAtypical test ring is shown in Fig. 2.The testring must have an outer diameter of 34.99 6 0.025 mm (1.3776 0.001 in.) with an eccentricity between the inner and outersurface of no greater than 0.00125 mm (0.0005 in.). Forcouples where surface condition

19、is not under study, it isrecommended that the outer diameter be a ground surface witha roughness of 0.152 to 0.305 m (6 to 12 in.) rms or centerline average (CLA), in the direction of motion. However,alternate surface conditions may be evaluated in the test, asdesired. It should be kept in mind that

20、 surface condition canhave an effect on sliding wear results.6.3 Test BlockAtest block is shown in Fig. 3. Block widthis 6.35 + 0.000, 0.025 mm (0.250 + 0.000, 0.001 in.). Forcouples where surface condition is not a parameter under study,a ground surface with the grinding marks running parallel toth

21、e long axis of the block and a roughness of 0.102 to 0.203 m(4 to 8 in.) CLA in the direction of motion is recommended.However, other surface conditions may be evaluated as de-sired.6.4 Analytical Balance, capable of measuring to the nearest0.1 mg.6.5 Optical Device (or equivalent), with metric or i

22、nch-pound unit calibration, is also necessary so that scar width canbe measured with a precision of 0.005 mm (0.0002 in.) orequivalent.7. Reagents7.1 Methanol.8. Preparation and Calibration of Apparatus8.1 Run the calibration procedure that is in Test MethodD2714 to ensure good mechanical operation

23、of the testequipment.9. Procedure9.1 Clean the block and ring using a procedure that willremove any scale, oil film, or residue without damaging thesurface.9.1.1 For metals, the following procedure is recommended:clean the block and ring in a non-chlorine containing solvent,ultrasonically, if possib

24、le; a methanol rinse may be used toremove any traces of solvent residue. Allow the blocks andrings 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 rin

25、g, as necessary.Note that a surface profile does not completely describe asurface 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 Demagnetize the metal specimens and ferrous assemb

26、ly.Weigh the block and ring to the nearest 0.1 mg.9.4 Measure the block width and ring diameter to thenearest 0.025 mm (0.001 in.).9.5 Clean the self-aligning block holder, ring shaft, andlubricant reservoir with solvent.9.6 Put the self-aligning block holder on the block.9.7 Place the block in posi

27、tion on the machine and, whileholding the block in position, place the ring on the shaft andlock the ring in place, using a test method in accordance withthe requirements of the specific machine design.9.8 Center the block on the ring while placing a lightmanual pressure on the lever arm to bring th

28、e block and ringinto contact. Be sure the edge of the block is parallel to theedge of the ring and that the mating surfaces are perfectlyaligned. This is accomplished by making sure the specimenholder is free during mounting so that the self-aligning blockholder can properly seat itself. Release the

29、 pressure on thelever arm.9.9 One may choose either a preloading or a step-loadingprocedure. Generally, preloading is chosen for variable speed3Several machines have been found satisfactory for the purposes of this test.These models may differ in lever arm ratio, load range, speed control (variable

30、orfixed), speed range, and type of friction measuring device.FIG. 1 Test SchematicG77172machines, while step-loading is chosen for fixed speed ma-chines in order to avoid an initial high wear transient. Thedifferences in the two procedures are indicated in 9.10 9.22.9.10 Place the required weights o

31、n the load bale and adjustthe lever arm in accordance with the requirements of thespecific machine design. Then remove the load by raising theweights, if using the preloading procedure, or by removing theweights if using the step-loading procedure.9.11 If running a lubricated test, clean all compone

32、nts thatwill come in contact with lubricant; fill the lubricant reservoirwith lubricant to 6.4 mm (0.25 in.) above the lower surface ofthe ring; rotate the ring several times.9.12 Set the revolution counter to zero.9.13 Gently lower the weights, applying the required load, ifusing the preloading pro

33、cedure.9.14 If using a variable speed machine, turn on the machineand slowly increase the power to the drive motor until the ringstarts to rotate, recording the “static” friction force. Continue toincrease the rate of rotation to the desired rate. If using a fixedspeed machine, simply turn on the ma

34、chine.9.15 If using step-loading, start the machine with noweights, then gently add a 133-N (30-lbf) load every 200 revuntil the required test load is reached. Adjust the rate ofrotation as needed. If the required load is less than 133 N, applythe load in one step.NOTE 1The outer diameter and concen

35、tricity with the inner diameter are the only critical parameters. The inner diameter is optional depending onmachine design. The inside diameter taper shown fits a number of standard machines.FIG. 2 Test RingFIG. 3 Test BlockG771739.16 During the test, record the friction force, lubricant orblock te

36、mperature, as required, and, if desired, the verticaldisplacement of the block.9.17 Stop the test manually or automatically after thedesired number of revolutions.49.18 A final “static” friction force may be measured with avariable speed machine. Leaving on the full load, wait 3 min 610 s, then turn

37、 on the machine and slowly increase the powerto the drive motor until the ring starts to rotate, recording the“static” final friction force. Then turn off the motor.9.19 Remove the block and ring, clean, and reweigh to thenearest 0.1 mg.9.20 Make surface roughness measurements and profilome-ter trac

38、es across the width of the block and the ring as desired.Atrace along the long axis of the block, through the wear scar,is also useful to verify the scar depth and shape.59.21 Measure the scar width on the test block in the centerand ;1 mm (0.04 in.) away from each edge. These measure-ments shall be

39、 to the nearest 0.025 mm (0.001 in.). Record theaverage of the three readings. Sometimes oxidation debris or alip of plastically deformed material will extend over the edgeof the wear scar (Fig. 4). When measuring scar width, try tovisually ignore this material or measure the scar width in anarea wh

40、ere this is not a problem.9.22 Tapered scars indicate improper block alignment dur-ing testing. If the three width measurements on a given scarhave a coefficient of variation of greater than 10 %, the testshall be declared invalid.45400 and 10 800 revolutions have been used for metals in interlabora

41、tory testprograms.5On some of the old test machines, it is possible for the block to move back andforth slightly, increasing the apparent size of the wear scar. If this problem issuspected, a profilometer trace through the wear scar will verify whether or not thescar shape corresponds to the curvatu

42、re of the ring.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 visuallyignored, but in this case scar curvature makes this too difficult. The test

43、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 fromthe scar measurement. The cross hair should be run to a visual average of the jagged edge, not to the point of a zig

44、zag.D. Tapered scar with jagged edges. This scar is too tapered (coefficient of variation 10 %); therefore, the test should be rerun.FIG. 4 Block ScarsG7717410. Calculation10.1 Calculation of Block Scar Volume:10.1.1 Block scar volume may be derived from block scarwidth by using Table 1 (applicable

45、only when ring diameter is34.99 6 0.025 mm (1.377 6 0.001 in.) and scar length (blockwidth) is 6.35 + 0.000, 0.025 mm (0.250 + 0.000, 0.001in.).10.1.2 The preferred method of calculating block scarvolume is by using the formula shown in Fig. 5. This formulamay be programmed on a calculator or comput

46、er.10.1.3 Block scar volume is not calculated generally fromblock mass loss because block mass is subject to effects ofmaterials transfer, generation of oxide films, or penetration ofthe material by the lubricant. Keeping in mind the abovefactors, block mass loss may be interpreted semiquantitativel

47、yin a comparative evaluation of various material couples. If theblock scar cannot be accurately measured following 9.21 andthe guidance in Fig. 4, a scar volume should not be calculated,but a notation made of the problem; for example, materialtransfer, plastic deformation, and so forth.10.2 Calculat

48、e coefficient of friction values from frictionforce values as follows:f 5 F/W (1)where:f = coefficient of frictionF = measured friction force, N (lbf), andW = normal force, N (lbf).10.3 Calculate ring volume loss as follows:volume loss 5ring mass lossring density(2)NOTE 1If the ring gains mass durin

49、g the test, the volume loss isreported as zero with a notation that weight gain occurred. Mass loss iseffected by material transfer from one component to another, by genera-tion of oxide films, or by infiltration into porous material by the lubricant,or combinations thereof. If material transfer to the ring is obvious, then aring scar volume should not be calculated from the weight lossmeasurement, but a notation should be made that material transferoccurred.11. Report11.1 Report any unusual event or an overload shutoff of themachine (on some