ASTM_D_968_-_22.pdf

Designation:D96822Standard Test Methods forAbrasion Resistance of Organic Coatings by FallingAbrasive1This standard is issued under the fixed designation D968;the number immediately following the designation indicates the year oforiginal adoption 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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 These test methods cover the determination of theresistance of organic coatings to abrasion produced by abrasivefalling onto coatings applied to a plane rigid surface,such as ametal or glass panel.1.2 Two test methods based on different abrasives arecovered as follows:SectionsMethod AFalling Sand Abrasion Test6 13Method BFalling Silicon Carbide Abrasion Test14 211.3 These methods should be restricted to testing in onlyone laboratory when numerical values are used because of thepoor reproducibility of the methods(see 13.1.2 and 21.1.2).Interlaboratory agreement is improved significantly when rank-ing is used in place of numerical values.1.4 The values stated in SI units are to be regarded as thestandard.The values given in parentheses after SI units are forinformation only and are not considered standard.1.5 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint,Related Coatings,Materials,andApplicationsD823 Practices for Producing Films of Uniform Thicknessof Paint,Coatings and Related Products on Test PanelsD1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD7091 Practice for Nondestructive Measurement of DryFilm Thickness of Nonmagnetic Coatings Applied toFerrous Metals and Nonmagnetic,Nonconductive Coat-ings Applied to Non-Ferrous MetalsE11 Specification for Woven Wire Test Sieve Cloth and TestSieves2.2 Other Standards:ANSI B74.12 Specification for the Size of Abrasive Grain Grinding Wheels,Polishing and General IndustrialUses3FEPA Standard 42-2 Grains of Fused Aluminum Oxide,Silicon Carbide and other Abrasive Materials for BondedAbrasives and for General Applications MicrogritsF230 to F200043.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 Abrasion resistance is expressed as the amount ofabrasive required to wear through a unit film thickness of thecoating.3.2 For definitions of other terms used in this standard,referto Terminology D16.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.23 on Physical Properties of Applied PaintFilms.Current edition approved June 1,2022.Published July 2022.Originally approvedin 1948.Last previous edition approved in 2017 as D968 17.DOI:10.1520/D0968-22.2For 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.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.4Available from Federation of European Producers of Abrasives(FEPA),20 av.,Reille,Paris,F-75014,www.fepa-.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.14.Summary of Test Method4.1 Abrasive particles fall from a specified height through aguide tube onto the surface of a coated panel until the film isworn away,exposing a small area of the substrate or previouscoating layer if two or more coatings are present.The amountof abrasive per unit film thickness is reported as the abrasionresistance of the coating on the panel.Silica sand or siliconcarbide may be used,as specified.5.Significance and Use5.1 Silica sand produces a slower rate of abrasion fororganic coatings than that provided by silicon carbide.Forso