1、Designation: G 137 97 (Reapproved 2003)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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a laboratory procedure tomeasure the resistance of
3、plastic 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 t
4、heload, 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 s
5、ingle- 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:D 618 Practice for Conditioning Plastics for Testing2D 3702 Test Method for W
7、ear Rate and Coefficient ofMaterials in Self-Lubricated Rubbing Contact Using aThrust Washer Testing Machine3E 122 Practice for Calculating Sample Size to Estimate,With a Specified Tolerable Error, the Average for Charac-teristic of a Lot or Process4E 177 Practice for Use of the Terms Precision and
8、Bias inASTM Test Methods4G 40 Terminology Relating to Wear and Erosion5G 77 Test Method for Ranking Resistance of Materials toSliding Wear Using Block-on-Ring Wear Test5G 117 Guide for Calculating and Reporting Measures ofPrecision Using Data from Interlaboratory Wear or Ero-sion Tests53. Terminolog
9、y3.1 Definitions:3.1.1 weardamage 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 G 40.3.2 Definitions of Terms Specific to T
10、his Standard:3.2.1 specific 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 th
11、e test when the specificwear rate remains substantially constant (the specific wear 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
12、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 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 relat
13、ive velocity. Thisis achieved using a block-on-ring configuration as illustrated inFig. 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
14、measurements made after thesteady state is established are used to determine the steady 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
15、is the direct responsibility of Subcommittee G02.40 on Non-Abrasive Wear.Current edition approved June 10, 2003. Published July 2003. Originallyapproved in 1995. Last previous edition appeared in 1997 as G 137 97.2Annual Book of ASTM Standards, Vol 08.01.3Annual Book of ASTM Standards, Vol 05.02.4An
16、nual Book of ASTM Standards, Vol 14.02.5Annual Book of ASTM Standards, Vol 03.02.1Copyright 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 o
17、f friction for the testcombination.NOTE 1Another test method that utilizes a block-on-ring test configu-ration for the evaluation of plastics is Test Method G 77.5. Significance and Use5.1 The specific wear rates determined by this test methodcan be used as a guide in ranking the wear resistance of
18、plasticmaterials. 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 testproce
19、dure and the 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 s
20、peeds and 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 Set
21、upAn example 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 a
22、nd sliding 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 bea
23、rings.6.1.2 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 beari
24、ng are industrial-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
25、 the direction 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 resul
26、ts will be 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 (2003)2width, 6.00 + 0.00, 0.03-mm (0.236 + 0.000, 0.001-in.)
27、depth, and 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, othe
28、r surface 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
29、 Suitable 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
30、Safety Data Sheet (MSDS) before using thesolvents.8. Preparation and Calibration of Apparatus8.1 Perform calibration of torque transducers by applyingNIST traceable dead weight standards and using a referenceload cell.68.2 Perform calibration of tachometer by comparison to ahand-held tachometer whic
31、h has been 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 D 618 for those samples where conditioning is re-quir
32、ed.6The interlaboratory 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 (2003)39.2 Test ConditionsThe recommended conditions are
33、 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. After-wards, clean the counterface ring in an ultrasonic acetone bathfor 2 h (43 kHz
34、 95 W) to remove 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
35、-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 specimen holder andtighten so that the test b
36、lock 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 specimen load shaft slides on and an al
37、ignmentscrew 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 and2 in Fig. 1 are of equal weight and will not figure intocalculations. The weight
38、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 small load cell can bemounted between
39、 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 by the machine itself(should not b
40、e 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.10.10 Bring the lever arm angle adj
41、usting 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 may be obtained. Values forthe fr
42、ictional 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 steady state is established. Theinter
43、vals 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 the speed controlling motor for we
44、ight 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 worn particlesfrom the test block and
45、 from within the 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
46、specimen holder 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
47、,v = velocity, m/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 Bloc
48、kG 137 97 (2003)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 v
49、alue in the steady 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), and1
