1、Designation: G137 97 (Reapproved 2017)Standard Test Method forRanking Resistance of Plastic Materials to Sliding WearUsing a Block-On-Ring Configuration1This standard is issued under the fixed designation G137; the number immediately following the designation indicates the year oforiginal adoption o
2、r, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a laboratory procedure tomeasure the resistance of pla
3、stic materials under dry slidingconditions. The test utilizes a block-on-ring geometry to rankmaterials according to their sliding wear characteristics undervarious conditions.1.2 The test specimens are small so that they can be moldedor cut from fabricated plastic parts. The test may be run at thel
4、oad, velocity, and temperature which simulate the servicecondition.1.3 Wear test results are reported as specific wear ratescalculated from volume loss, sliding distance, and load. Mate-rials with superior wear resistance have lower specific wearrates.1.4 This test method allows the use of both sing
5、le- andmulti-station apparatus to determine the specific wear rates.1.5 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. I
6、t is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on
7、 standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics
8、for TestingD3702 Test Method for Wear Rate and Coefficient of Fric-tion of Materials in Self-Lubricated Rubbing ContactUsing a Thrust Washer Testing MachineE122 Practice for Calculating Sample Size to Estimate, WithSpecified Precision, the Average for a Characteristic of aLot or ProcessG40 Terminolo
9、gy Relating to Wear and ErosionG77 Test Method for Ranking Resistance of Materials toSliding Wear Using Block-on-Ring Wear TestG117 Guide for Calculating and Reporting Measures ofPrecision Using Data from Interlaboratory Wear or Ero-sion Tests (Withdrawn 2016)33. Terminology3.1 Definitions:3.1.1 wea
10、rdamage to a solid surface, generally involvingprogressive loss of material, due to relative motion betweenthat surface and a contacting substance or substances.3.1.2 Additional definitions relating to wear are found inTerminology G40.3.2 Definitions of Terms Specific to This Standard:3.2.1 specific
11、 wear ratethe volume loss per unit slidingdistance, divided by the load. It can be calculated as the volumeloss per unit time, divided by the load and the sliding velocity.3.2.2 steady state specific wear ratethe specific wear ratethat is established during that part of the test when the specificwea
12、r rate remains substantially constant (the specific wear rateversus sliding distance curve flattens out considerably with lessthan 30 % difference between the specific wear rates) during a1This test method is under the jurisdiction of ASTM Committee G02 on Wearand Erosion and is the direct responsib
13、ility of Subcommittee G02.40 on Non-Abrasive Wear.Current edition approved Nov. 1, 2017. Published December 2017. Originallyapproved in 1995. Last previous edition appeared in 2009 as G137 97 (2009).DOI: 10.1520/G0137-97R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcont
14、act ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive,
15、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 International Standards, Guides and Recommendations issued
16、 by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1minimum of three time intervals spanning a total time durationof at least 18 h, with ideally no single interval exceeding 8 h.However, one time interval during the steady state can be aslong as 16 h.4. Summary of Test Meth
17、od4.1 A plastic block of known dimensions is brought intocontact with a counterface ring (usually metal) under con-trolled conditions of contact pressure and relative velocity.Thisis achieved using a block-on-ring configuration as illustrated inFig. 1. Periodic weighing of the polymer block results
18、in anumber of mass-time data points where the time relates to thetime of sliding. The test is continued until the steady state wearrate is established. Mass loss measurements made after thesteady state is established are used to determine the steady statespecific wear rate, which is the volume loss
19、per unit slidingdistance per unit load. The frictional torque may also bemeasured during the steady state using a load cell. These datacan be used to evaluate the coefficiency of friction for the testcombination.NOTE 1Another test method that utilizes a block-on-ring test configu-ration for the eval
20、uation of plastics is Test Method G77.5. Significance and Use5.1 The specific wear rates determined by this test methodcan be used as a guide in ranking the wear resistance of plasticmaterials. The specific wear rate is not a material property andwill therefore differ with test conditions and test g
21、eometries.The significance of this test will depend on the relativesimilarity to the actual service conditions.5.2 This test method seeks only to describe the general testprocedure and the procedure for calculating and reporting data.NOTE 2This test configuration allows steady state specific wear ra
22、testo be achieved very quickly through the use of high loads and speeds. Thethrust washer configuration described in Test Method D3702 does notallow for the use of such high speeds and loads because of possibleoverheating (which may cause degradation or melting, or both) of thespecimen. Despite the
23、differences in testing configurations, a goodcorrelation in the ranking of wear resistance is achieved between the twotests (Table X2.1).6. Apparatus and Materials6.1 Test SetupAn example of the basic test configurationand part names are shown in Fig. 1. The recommendeddimensions of the test apparat
24、us are shown in Fig. 2. Thefigures shown in this test method represent one example of ablock-on-ring test apparatus. The mandatory elements are: thecapability to change load and sliding speed, the ability toreposition the specimen after weighing as before, and acounterface ring with acceptable eccen
25、tricity. All other designelements can be varied according to the user preference.6.1.1 Bearings recommended for counterface drive shaftsare industrial-grade tapered roller bearings.6.1.2 Required centerline alignment limits of the counter-face drive shafts are 60.41 mm (60.016 in.) from the center o
26、fFIG. 1 Single Station Block-on-Ring ArrangementG137 97 (2017)2a counterface ring. Allowable eccentricity of the counterfacering is no greater than 60.06 mm (60.002 in.).6.1.3 Bearings recommended for the linear ball groovedbushing bearing are industrial-grade linear bearings.6.2 Counterface RingThe
27、 recommended dimensions forthe counterface ring are 100 + 0.05, 0.00-mm diameter and15.88 + 0.30, 0.13-mm width. Often a hardened tool steelring with a hardness of 50 to 60 HRC and a surface roughnessof 0.102 to 0.203 m (4 to 8 in.) Rain the direction of slidingis used for the general evaluation of
28、plastics. The requirementfor the ring material is that it should not wear appreciably orchange dimensions during the course of the test. Therefore,other materials and surface conditions may also be used. Itshould be noted that test results will be influenced by thechoice of ring material and surface
29、 roughness.6.3 Test BlockThe recommended dimensions of the testblock are 6.35 + 0.00, 0.03-mm (0.250 + 0.000, 0.001-in.)width, 6.00 + 0.00, 0.03-mm (0.236 + 0.000, 0.001-in.)depth, and 12.70 6 0.2-mm height. For materials wheresurface condition is not a parameter under study, a groundsurface with th
30、e grinding marks running parallel to the depthdirection of the block and a roughness of 0.102 to 0.203 m (4to 8 in.) Rain the direction of motion is recommended.However, other surface conditions may be evaluated as de-sired.6.4 Test Parameters:6.4.1 The recommended range for the normal load is from2
31、0 to 40 N.6.4.2 The recommended range for the velocity is from 0.5 to1 m/s.6.5 Apparatus:6.5.1 Analytical Balance, capable of measuring to the near-est 0.01 mg.7. Reagents7.1 Suitable cleaning procedures should be used to cleancounterface ring and test block. Reagents proven suitable forsome materia
32、ls are:7.1.1 Acetone, for steel rings, and7.1.2 Methanol, for test block surface and specimen holder.7.2 Both solvents are flammable and toxic. Refer to therelevant Material Safety Data Sheet (MSDS) before using thesolvents.NOTE 1All dimensions are given in millimetres.FIG. 2 Recommended Dimensions
33、of Block-on-Ring ApparatusG137 97 (2017)38. Preparation and Calibration of Apparatus8.1 Perform calibration of torque transducers4by applyingNIST traceable dead weight standards and using a referenceload cell.8.2 Perform calibration of tachometer by comparison to ahandheld tachometer which has been
34、calibrated with NISTtraceable standards.9. Conditioning9.1 ConditioningCondition the test specimens at 23 62C (73.4 6 3.6F) and 50 6 5 % relative humidity for not lessthan 40 h prior to testing in accordance with Procedure A ofPractice D618 for those samples where conditioning is re-quired.9.2 Test
35、ConditionsThe recommended conditions are thestandard laboratory atmosphere of 23 6 2C (73.4 6 3.6F)and 50 6 5 % relative humidity.10. Procedure10.1 Clean the counterface ring using mild soap and waterso as to remove bulk dirt and corrosion-inhibiting oil.Afterwards, clean the counterface ring in an
36、ultrasonic acetonebath for 2 h (43 kHz 95 W) to remove the remainingcontaminants. Allow the ring to dry completely. Handle thering from this point on with lint-free cotton gloves.10.2 Mount the counterface ring on the drive shaft andsecure with a counterface retaining nut (Fig. 1).10.3 Clean the tes
37、t block and specimen holder with metha-nol. Handle the test block and the specimen holder withlint-free cotton gloves from this point.10.4 Measure the width and the depth of the test block toensure that the surface dimensions fall within the specifica-tions.10.5 Mount the test block into the specime
38、n holder andtighten so that the test block does not move within thespecimen holder (Fig. 3).10.6 Weigh the test block and specimen holder to thenearest 0.01 mg.10.7 Position the specimen holder with the test block underthe counterface ring. Repositioning is possible with the use ofa guide that the s
39、pecimen load shaft slides on and an alignmentscrew which secures the specimen holder to the specimen loadshaft. The linear ball grooved bushing bearing prevents thespecimen load shaft from rotating.10.8 Apply the required load.Yokes 1 and 2, and Nuts 1 and2inFig. 1 are of equal weight and will not f
40、igure intocalculations. The weight of the weight hanger will be includedin the total weight needed. The weight of specimen, specimenholder, specimen load shaft, and lever arm angle adjusting rodwill have to be countered to equal the desired force. To ensurethat the proper load has been applied, a sm
41、all load cell can bemounted between the specimen and the counterface ring withthe load being applied. The lever arm should be maintainedhorizontally by adjusting the height of the lever arm angleadjusting rod. The required load can be applied by othermechanisms.10.9 Frictional torque values produced
42、 by the machine itself(should not be more than 60.05 Nm) should be zeroed asfollows:10.9.1 The block-on-ring tester is turned on without anyload being applied to the specimen. This gives a stable torquereading which should be zeroed.After zero marker is obtained,load may be applied to run the test.1
43、0.10 Bring the lever arm angle adjusting rod gently intocontact with the specimen load shaft to apply the load.10.11 Start the motor and adjust to a desired speed. Thespeed should preferably not exceed 1 m/s.10.11.1 Frictional torque values may be recorded so that anaverage value for the test period
44、 may be obtained. Values forthe frictional force can be obtained from these measurementsby dividing the frictional torque by an appropriate momentarm.10.12 The test should be interrupted a minimum of six timesto determine mass loss as a function of time, though more maybe required to ensure that ste
45、ady state is established. Theintervals need not be uniform. Shorter intervals should be usedduring the initial portion of the test and longer intervals duringthe latter portion of the test. The test should be continued untilthree or more of the intervals occur in the steady state range.10.12.1 Halt
46、the speed controlling motor for weight mea-surements.10.12.2 Remove the load from the test block by removingthe lever arm angle adjusting rod from the specimen load shaft.10.12.3 Remove the specimen holder with the test blockfrom the specimen load shaft.10.12.4 Use compressed air to blow off the wor
47、n particlesfrom the test block and from within the specimen holder.10.12.5 Weigh the specimen holder with the test block on abalance to the nearest 0.01 mg.4The interlaboratory tests were conducted using the torque transducers manu-factured by Key Transducers, Inc., Sterling Heights, MI.NOTE 1All di
48、mensions are given in millimetres.FIG. 3 Specimen Holder With a Test BlockG137 97 (2017)410.12.6 Reload the specimen holder with the test blockfollowing the procedure in 10.7 10.11.11. Calculation11.1 Calculation of Specific Wear Rate:11.1.1 Periodic weighing of the specimen holder and the testblock
49、 results in a number of mass-time data points where thetime relates to the time of sliding.11.1.2 The specific wear rate for each interval can becalculated from (Eq 1):Ws51FNvmt(1)where:Ws= specific wear rate, mm3/Nm, dimensions, (L2/F),FN= applied normal force, N,v = velocity, m/s, = density, kg/mm3,m = mass loss, kg, andt = time interval, s.11.1.3 The specific wear rate reported is the average valuewithin the steady state region.11.2 Calculation of Coeffcient of Friction:11.2.1 The dynamic coefficient of friction is calculated asfollo
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