ASTM_G_77_-_05_2010.pdf

Designation:G7705(Reapproved 2010)Standard 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 year 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 testutilizes 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 can 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 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 higherwear 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 regulatory limitations prior to use.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 Characteristic 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 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 For additional definitions pertinent 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 friction 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 program directed toward a service applicationwill 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 method 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 test geometry is shown in Fig.1.31This 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 April 1,2010.Published May 2010.Originallyapproved in 1983.Last previous edition approved in 2005 as G77051.DOI:10.1520/G0077-05R10.2For 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.3Several machines have been found satisfactory for the purposes of this test.These models may differ in lever arm ratio,load range,speed control(variable orfixed),speed range,and type of friction measuring device.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.2 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 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.How