ASTM_G_40_-_15.pdf

Designation:G4015Standard Terminology Relating toWear and Erosion1This standard is issued under the fixed designation G40;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 The terms and their definitions given herein representterminology relating to wear and erosion of solid bodies due tomechanical interactions such as occur with cavitation,im-pingement by liquid jets or drops or by solid particles,orrelative motion against contacting solid surfaces or fluids.Thisscope interfaces with but generally excludes those processeswhere material loss is wholly or principally due to chemicalaction and other related technical fields as,for instance,lubrication.1.2 This terminology is not exhaustive;the absence of anyparticular term from this collection does not necessarily implythat its use within this scope is discouraged.However,theterms given herein are the recommended terms for the conceptsthey represent unless otherwise noted.1.3 Certain general terms and definitions may be restrictedand interpreted,if necessary,to make them particularly appli-cable to the scope as defined herein.1.4 The purpose of this terminology is to encourage unifor-mity and accuracy in the description of test methods anddevices and in the reporting of test results in relation to wearand erosion.NOTE1All terms are listed alphabetically.When a subsidiary term isdefined in conjunction with the definition of a more generic term,analphabetically-listed cross-reference is provided.2.Referenced Documents2.1 ASTM Standards:2C242 Terminology of Ceramic Whitewares and RelatedProducts3.Terminologyabradant,na material that is producing,or has produced,abrasive wear.abrasion,nin tribology,the process by which relativemotion between a surface and hard particles or protuber-ances on an opposing surface produces abrasive wear of thatsurface.(See also abrasive wear.)abrasive wear,nwear due to hard particles or hard protu-berances forced against and moving along a solid surface.abrasion-corrosion,na synergistic process involving bothabrasive wear and corrosion in which each of these processesis affected by the simultaneous action of the other and,inmany cases,is thereby accelerated.abrasivity,nthe ability of a material or substance to causeabrasive wear.absolute impact velocitySee impact velocity.acceleration period,nin cavitation and liquid impingementerosion,the stage following the incubation period duringwhich the erosion rate increases from near zero to amaximum value.(See also erosion rate-time pattern.)accumulation period,nin cavitation and liquid impinge-ment erosion,a less-preferred term for acceleration period.adhesive wear,nwear due to localized bonding betweencontacting solid surfaces leading to material transfer be-tween the two surfaces or loss from either surface.angle of attack,nin impingement erosion,the angle betweenthe direction of motion of an impinging liquid or solidparticle and the tangent to the surface at the point of impact.angle of incidence,nin impingement erosion,the anglebetween the direction of motion of an impinging liquid orsolid particle and the normal to the surface at the point ofimpact.apparent area of contact,nin tribology,the area of contactbetween two solid surfaces defined by the boundaries of theirmacroscopic interface.(Contrast with real area of contact.)asperity,nin tribology,a protuberance in the small-scaletopographical irregularities of a solid surface.attenuation period,nin cavitation and liquid impingementerosion,a less-preferred term for deceleration period.average erosion rate,na less preferred term for cumulativeerosion rate.(See also interval erosion rate.)1This terminology is under the jurisdiction of ASTM Committee G02 on Wearand Erosion and is the direct responsibility of Subcommittee G02.91 on Terminol-ogy.Current edition approved Nov.1,2015.Published November 2015.Originallyapproved in 1973.Last previous edition approved in 2013 as G40 13.DOI:10.1520/G0040-15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 Beilby layer,nan altered surface layer of supposedly amor-phous material formed on a crystalline solid during mechani-cal polishing,whose existence was proposed in Sir GeorgeBeilbys writings.The existence of such a layer is notsupported by recent research,and the use of this term istherefore considered archaic and is strongly discouraged.bio-tribocorrosion,nin the field of medical devices anddental restoratives,a form of tribocorrosion in which bio-logical substa