1、Designation:G20611Standard Guide forMeasuring the Wear Volumes of Piston Ring Segments Runagainst Flat Coupons in Reciprocating Wear Tests1This standard is issued under the fixed designation G206;the number immediately following the designation indicates the year oforiginal adoption or,in the case o
2、f 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 guide covers and describes a profiling method foruse accurately measuring the wear loss of comp
3、ound-curved(crowned)piston ring specimens that run against flat counter-faces.It does not assume that the wear scars are ideally flat,asdo some alternative measurement methods.Laboratory-scalewear tests have been used to evaluate the wear of materials,coatings,and surface treatments that are candida
4、tes for pistonrings and cylinder liners in diesel engines or spark ignitionengines.Various loads,temperatures,speeds,lubricants,anddurations are used for such tests,but some of them use a curvedpiston ring segment as one sliding partner and a flat or curvedspecimen(simulating the cylinder liner)as i
5、ts counterface.Thegoal of this guide is to provide more accurate wear measure-ments than alternative approaches involving weight loss orsimply measuring the length and width of the wear marks.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is
6、 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:2G40 Terminology Relating to Wear and ErosionG181 Test Method for Conducting Friction
7、 Tests of PistonRing and Cylinder Liner Materials Under LubricatedConditions3.Terminology3.1 DefinitionsSee Terminology G40.3.2 Definitions of Terms Specific to This Standard:3.2.1 conformal contact,nin friction and wear testing,any macro-geometric specimen configuration in which thecurvature of one
8、 contact surface matches that of the counter-face.3.2.1.1 DiscussionExamples of conformal contact includea flat surface sliding on a flat surface and a ball rotating in asocket that conforms to the shape of the ball.Apair of surfacesmay begin a wear or friction test in a non-conforming contactconfig
9、uration,but develop a conformal contact as a result ofwear.3.2.2 cylinder bore/cylinder liner,nin an internal combus-tion engine,the cylindrical cavity in which the piston moves.3.2.2.1 DiscussionThe terms cylinder bore and cylinderliner are used interchangeably in the description of thismethod.Cyli
10、nder liners are most commonly used in heavy-duty engines which are intended to be rebuilt.They are sleeves,generally of a cast iron,which are surrounded on their outersurface by coolant for better heat transfer,and meant to bereplaced when excessively worn.A cylinder bore is machineddirectly into an
11、 engine block and is more commonly used inlight-duty engines which are not meant for rebuilding.Thematerial of the cylinder bore is,therefore,the same material asthe engine block,however the inside surface of the bore may ormay not have additional surface treatment.4.Summary of Guide4.1 A reciprocat
12、ing wear testing apparatus is used to simu-late the back-and-forth motion of a piston ring within acylinder bore in the presence of a heated lubricant.Dependingon the duration and severity of the imposed test conditions,some degree of wear is generally produced on one or bothmembers of the sliding p
13、air.Mathematical models of the wearscar geometry on both the piston ring and cylinder linersurfaces allow the degree of wear to be quantified in terms ofvolume lost.The contact geometry for such tests,in the contextof ring-on-liner frictional behavior,is exemplified in PracticeG181.That method uses
14、pre-worn-in surfaces,and therefore itdiffers from the present case in which wear loss is based onmeasurements of initial and final profiles of the test specimens.5.Significance and Use5.1 The practical life of an internal combustion engine ismost often determined by monitoring its oil consumption.1T
15、his guide is under the jurisdiction of ASTM Committee G02 on Wear andErosion and is the direct responsibility of Subcommittee G02.40 on Non-AbrasiveWear.Current edition approved May 1,2011.Published May 2011.DOI:10.1520/G020611.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcon
16、tact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 Excessive oil consumption is cause for engine repair orreplacement and can be symptomatic of excessive wear of thepiston ring or the cylinder bore or both.More wear-resistantmaterials of construction can extend engine life and r
