1、Designation: G 137 97 (Reapproved 2009)Standard Test Method forRanking Resistance of Plastic Materials to Sliding WearUsing a Block-On-Ring Configuration1This standard is issued under the fixed designation G 137; the number immediately following the designation indicates the year oforiginal adoption
2、 or, 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 p
3、lastic 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 th
4、eload, 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 si
5、ngle- 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.
6、 It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 3702 Test Method for We
7、ar Rate and Coefficient ofFriction of Materials in Self-Lubricated Rubbing ContactUsing a Thrust Washer Testing MachineE 122 Practice for Calculating Sample Size to Estimate,With Specified Precision, the Average for a Characteristicof a Lot or ProcessG40 Terminology Relating to Wear and ErosionG77 T
8、est 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 Tests3. Terminology3.1 Definitions:3.1.1 weardamage to a solid surface, generally involvingprogres
9、sive 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 wear ratethe volume loss per unit slidingdistance, di
10、vided 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 specificwear rate remains substantially constant (the specific we
11、ar rateversus sliding distance curve flattens out considerably with lessthan 30 % difference between the specific wear rates) during aminimum 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 st
12、eady state can be aslong as 16 h.4. Summary of Test Method4.1 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 i
13、nFig. 1. Periodic weighing of the polymer block results 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 s
14、teady statespecific wear rate, which is the volume loss per unit slidingdistance per unit load. The frictional torque may also be1This test method is under the jurisdiction of ASTM Committee G02 on Wearand Erosion and is the direct responsibility of Subcommittee G02.40 on Non-Abrasive Wear.Current e
15、dition approved May 1, 2009. Published May 2009. Originallyapproved in 1995. Last previous edition appeared in 2003 as G 13797(2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume infor
16、mation, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.measured during the steady state using a load cell. These datacan be used to evaluate the coefficiency of frictio
17、n for the testcombination.NOTE 1Another test method that utilizes a block-on-ring test configu-ration for the evaluation 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 plasticmat
18、erials. The specific wear rate is not a material property andwill therefore differ with test conditions and test geometries.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 t
19、he procedure for calculating and reporting data.NOTE 2This test configuration allows steady state specific wear ratesto be achieved very quickly through the use of high loads and speeds. Thethrust washer configuration described in Test Method D 3702 does notallow for the use of such high speeds and
20、loads because of possibleoverheating (which may cause degradation or melting, or both) of thespecimen. Despite the 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 examp
21、le of the basic test configurationand part names are shown in Fig. 1. The recommendeddimensions of the test apparatus 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
22、 speed, the ability toreposition the specimen after weighing as before, and acounterface ring with acceptable eccentricity. 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.
23、2 Required centerline alignment limits of the counter-face drive shafts are 60.41 mm (60.016 in.) from the center ofa 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 ind
24、ustrial-grade linear bearings.6.2 Counterface RingThe 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 direc
25、tion of slidingis used for the general evaluation of 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
26、 influenced by thechoice of ring material and surface 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.)FIG. 1 Single Station Block-on-Ring ArrangementG 137 97 (2009)2width, 6.00 + 0.00, 0.03-mm (0.236 + 0.000, 0.001-in.)depth, and
27、 12.70 6 0.2-mm height. For materials wheresurface condition is not a parameter under study, a groundsurface with the 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
28、conditions may be evaluated as de-sired.6.4 Test Parameters:6.4.1 The recommended range for the normal load is from20 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
29、cleaning procedures should be used to cleancounterface ring and test block. Reagents proven suitable forsome materials 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 Dat
30、a Sheet (MSDS) before using thesolvents.8. Preparation and Calibration of Apparatus8.1 Perform calibration of torque transducers3by applyingNIST traceable dead weight standards and using a referenceload cell.8.2 Perform calibration of tachometer by comparison to ahandheld tachometer which has been c
31、alibrated 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 D 618 for those samples where conditioning is re-quired.3The inte
32、rlaboratory tests were conducted using the torque transducers manu-factured by Key Transducers, Inc., Sterling Heights, MI.NOTEAll dimensions are given in millimetres.FIG. 2 Recommended Dimensions of Block-on-Ring ApparatusG 137 97 (2009)39.2 Test ConditionsThe recommended conditions are thestandard
33、 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. After-wards, clean the counterface ring in an ultrasonic acetone bathfor 2 h (43 kHz 95 W) to re
34、move the remaining contaminants.Allow the ring to dry completely. Handle the ring from thispoint 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 test block and specimen holder with metha-nol. Handle
35、 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 specimen holder andtighten so that the test block does no
36、t 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 specimen load shaft slides on and an alignmentscrew
37、 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 figure intocalculations. The weight of the weight h
38、anger 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 small load cell can bemounted between the specimen a
39、nd 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 by the machine itself(should not be more than 60.
40、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.10.10 Bring the lever arm angle adjusting rod gentl
41、y 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 may be obtained. Values forthe frictional force c
42、an 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 steady state is established. Theintervals need not be
43、 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 the speed controlling motor for weight mea-suremen
44、ts.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 worn particlesfrom the test block and from within the
45、 specimen holder.10.12.5 Weigh the specimen holder with the test block on abalance to the nearest 0.01 mg.10.12.6 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
46、and the testblock 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):Ws51FNvrDmDt(1)where:Ws= specific wear rate, mm3/Nm, dimensions, (L2/F),FN= applied normal force, N,v = velocity, m
47、/s,r = density, kg/mm3,Dm = mass loss, kg, andDt = 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:NOTEAll dimensions are given in millimetres.FIG. 3 Specimen Holder With a Test BlockG 137 97 (2009)
48、411.2.1 The dynamic coefficient of friction is calculated asfollows: 5 Ff/FN(2)where: = coefficient of friction,Ff= frictional force calculated from measured frictionaltorque, andFN= applied normal force.11.2.2 The dynamic coefficient of friction which may bereported is the average value in the stea
49、dy state region.12. Report12.1 Report the following test parameters:12.1.1 Counterface ring material, hardness, and roughness,12.1.2 Test block material,12.1.3 Counterface ring RPM and surface speed, m/s,12.1.4 Applied normal force, N, and12.1.5 Temperature and humidity.12.2 Report the following results:12.2.1 A table of sliding times and the corresponding masslosses,12.2.2 A table of sliding times and the correspondingspecific wear rates, mm3/Nm,12.2.3 The number of replicates (a minimum of threereplicates is recommended), and12.2.4 The stea
